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	diff --git a/etc/mtree/BSD.include.dist b/etc/mtree/BSD.include.dist
	--- a/etc/mtree/BSD.include.dist
	+++ b/etc/mtree/BSD.include.dist
	@@ -269,6 +269,10 @@
	..
	netinet6
	..
	+ netlink
	+ route
	+ ..
	+ ..
	netipsec
	..
	netnatm
	diff --git a/share/man/man4/netlink.4 b/share/man/man4/netlink.4
	new file mode 100644
	--- /dev/null
	+++ b/share/man/man4/netlink.4
	@@ -0,0 +1,343 @@
	+.\"
	+.\" Copyright (C) 2022 Alexander Chernikov <melifaro@FreeBSD.org>.
	+.\"
	+.\" Redistribution and use in source and binary forms, with or without
	+.\" modification, are permitted provided that the following conditions
	+.\" are met:
	+.\" 1. Redistributions of source code must retain the above copyright
	+.\" notice, this list of conditions and the following disclaimer.
	+.\" 2. Redistributions in binary form must reproduce the above copyright
	+.\" notice, this list of conditions and the following disclaimer in the
	+.\" documentation and/or other materials provided with the distribution.
	+.\"
	+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+.\" SUCH DAMAGE.
	+.\"
	+.\" $FreeBSD$
	+.\"
	+.Dd September 30, 2022
	+.Dt NETLINK 4
	+.Os
	+.Sh NAME
	+.Nm Netlink
	+.Nd Kernel network configuration protocol
	+.Sh SYNOPSIS
	+.In netlink/netlink.h
	+.In netlink/netlink_route.h
	+.Ft int
	+.Fn socket AF_NETLINK SOCK_DGRAM int family
	+.Sh DESCRIPTION
	+Netlink is a user-kernel message-based communication protocol primarily used
	+for network stack configuration.
	+Netlink is easily extendable and supports large dumps and event
	+notifications, all via a single socket.
	+The protocol is fully asynchronous, allowing one to issue and track multiple
	+requests at once.
	+Netlink consists of multiple families, which commonly group the commands
	+belonging to the particular kernel subsystem.
	+Currently, the supported families are:
	+.Pp
	+.Bd -literal -offset indent -compact
	+NETLINK_ROUTE network configuration,
	+NETLINK_GENERIC "container" family
	+.Ed
	+.Pp
	+The
	+.Dv NETLINK_ROUTE
	+family handles all interfaces, addresses, neighbors, routes, and VNETs
	+configuration.
	+More details can be found in
	+.Xr rtnetlink 4 .
	+The
	+.Dv NETLINK_GENERIC
	+family serves as a
	+.Do container Dc ,
	+allowing registering other families under the
	+.Dv NETLINK_GENERIC
	+umbrella.
	+This approach allows using single netlink socket to interact with
	+multiple netlink families at once.
	+More details can be found in
	+.Xr genetlink 4 .
	+.Pp
	+Netlink has its own sockaddr structure:
	+.Bd -literal
	+struct sockaddr_nl {
	+ uint8_t nl_len; /* sizeof(sockaddr_nl) */
	+ sa_family_t nl_family; /* netlink family */
	+ uint16_t nl_pad; /* reserved, set to 0 */
	+ uint32_t nl_pid; /* automatically selected, set to 0 */
	+ uint32_t nl_groups; /* multicast groups mask to bind to */
	+};
	+.Ed
	+.Pp
	+Typically, filling of this structure is not required for socket operations.
	+It is presented here for completeness.
	+.Sh PROTOCOL DESCRIPTION
	+The protocol is message-based.
	+Each message starts with the mandatory
	+.Va nlmsghdr
	+header, followed by the family-specific header and the list of
	+type-length-value pairs (TLVs).
	+TLVs can be nested.
	+All headers and TLVS are padded to 32-bit boundaries.
	+Each
	+.Xr send 2 or
	+.Xr recv 2
	+system call may contain multiple messages.
	+.Ss BASE HEADER
	+.Bd -literal
	+struct nlmsghdr {
	+ uint32_t nlmsg_len; /* Length of message including header */
	+ uint16_t nlmsg_type; /* Message type identifier */
	+ uint16_t nlmsg_flags; /* Flags (NLM_F_) */
	+ uint32_t nlmsg_seq; /* Sequence number */
	+ uint32_t nlmsg_pid; /* Sending process port ID */
	+};
	+.Ed
	+.Pp
	+The
	+.Va nlmsg_len
	+field stores the whole message length, in bytes, incuding the header.
	+This length has to be rounded up to the nearest 32-bit boundary when
	+iterating over messages.
	+.Va nlmsg_type
	+represents the command/request type.
	+This value is family-specific.
	+The list of supported commands can be found in the relevant family
	+header file.
	+.Va nlmsg_seq
	+is a user-provided request identifier.
	+An application can track the operation result using the
	+.Dv NLMSG_ERROR
	+messages and matching the
	+.Va nlmsg_seq
	+.
	+The
	+.Va nlmsg_pid
	+field is the message sender id.
	+This field is optional for userland.
	+The kernel sender ID is zero.
	+The
	+.Va nlmsg_flags
	+field contains the message-specific flags.
	+The following generic flags are defined:
	+.Pp
	+.Bd -literal -offset indent -compact
	+NLM_F_REQUEST Indicates that the message is an actual request to the kernel
	+NLM_F_ACK Request an explicit ACK message with an operation result
	+.Ed
	+.Pp
	+The following generic flags are defined for the "GET" request types:
	+.Pp
	+.Bd -literal -offset indent -compact
	+NLM_F_ROOT Return the whole dataset
	+NLM_F_MATCH Return all entries matching the criteria
	+.Ed
	+These two flags are typically used together, aliased to
	+.Dv NLM_F_DUMP
	+.Pp
	+The following generic flags are defined for the "NEW" request types:
	+.Pp
	+.Bd -literal -offset indent -compact
	+NLM_F_CREATE Create an object if none exists
	+NLM_F_EXCL Don't replace an object if it exists
	+NLM_F_REPLACE Replace an existing matching object
	+NLM_F_APPEND Append to an existing object
	+.Ed
	+.Pp
	+The following generic flags are defined for the replies:
	+.Pp
	+.Bd -literal -offset indent -compact
	+NLM_F_MULTI Indicates that the message is part of the message group
	+NLM_F_DUMP_INTR Indicates that the state dump was not completed
	+NLM_F_DUMP_FILTERED Indicates that the dump was filtered per request
	+NLM_F_CAPPED Indicates the original message was capped to its header
	+NLM_F_ACK_TLVS Indicates that extended ACK TLVs were included
	+.Ed
	+.Ss TLVs
	+Most attributes in the messages are encoded as type-length-value pairs
	+(TLVs).
	+The base TLV header:
	+.Bd -literal
	+struct nlattr {
	+ uint16_t nla_len; /* Total attribute length */
	+ uint16_t nla_type; /* Attribute type */
	+};
	+.Ed
	+The TLV type
	+.Pq Va nla_type
	+scope is typically the message type or group within a family.
	+For example, the
	+.Dv RTN_MULTICAST
	+type value is only valid for
	+.Dv RTM_NEWROUTE
	+,
	+.Dv RTM_DELROUTE
	+and
	+.Dv RTM_GETROUTE
	+messages.
	+TLVs can be nested; in that case internal TLVs may have their own sub-types.
	+All TLVs are packed with 32-bit padding.
	+.Ss CONTROL MESSAGES
	+A number of generic control messages are reserved in each family.
	+.Pp
	+.Dv NLMSG_ERROR
	+reports the operation result if requested, optionally followed by
	+the metadata TLVs.
	+The value of
	+.Va nlmsg_seq
	+is set to its value in the original messages, while
	+.Va nlmsg_pid
	+is set to the socket pid of the original socket.
	+The operation result is reported via
	+.Vt "struct nlmsgerr":
	+.Bd -literal
	+struct nlmsgerr {
	+ int error; /* Standard errno */
	+ struct nlmsghdr msg; /* Original message header */
	+};
	+.Ed
	+If the
	+.Dv NETLINK_CAP_ACK
	+socket option is not set, the remainder of the original message will follow.
	+If the
	+.Dv NETLINK_EXT_ACK
	+socket option is set, kernel may add a
	+.Dv NLMSGERR_ATTR_MSG
	+string TLV with the textual error description, optionally followed by the
	+.Dv NLMSGERR_ATTR_OFFS
	+TLV, indicating the offset from the message start that triggered an error.
	+.Pp
	+.Dv NLMSG_DONE
	+indicates the end of the message group: typically, the end of the dump.
	+It contains a single
	+.Vt int
	+field, describing the dump result as a standard errno value.
	+.Sh SOCKET OPTIONS
	+Netlink supports a number of custom socket options, which can be set with
	+.Xr setsockopt 2
	+with the
	+.Dv SOL_NETLINK
	+.Fa level :
	+.Bl -tag -width indent
	+.It Dv NETLINK_ADD_MEMBERSHIP
	+Subscribes to the notifications for the specific group (int).
	+.It Dv NETLINK_ADD_MEMBERSHIP
	+Unsubscribes from the notifications for the specific group (int).
	+.It Dv NETLINK_LIST_MEMBERSHIPS
	+Lists the memberships as a bitmask.
	+.It Dv NETLINK_CAP_ACK
	+Instructs the kernel to send the original message header in the reply
	+without the message body.
	+.It Dv NETLINK_EXT_ACK
	+Acknowledges capability to receive additional TLVs in the ACK message.
	+.El
	+.Pp
	+Additionally, netlink overrides the following socket options from the
	+.Dv SOL_SOCKET
	+.Fa level :
	+.Bl -tag -width indent
	+.It Dv SO_RCVBUF
	+Sets the maximum size of the socket receive buffer.
	+If the caller has
	+.Dv PRIV_NET_ROUTE
	+permission, the value can exceed the currently-set
	+.Va kern.ipc.maxsockbuf
	+value.
	+.El
	+.Sh SYSCTL VARIABLES
	+A set of
	+.Xr sysctl 8
	+variables is available to tweak run-time parameters:
	+.Bl -tag -width indent
	+.It Va net.netlink.sendspace
	+Default send buffer for the netlink socket.
	+Note that the socket sendspace has to be at least as long as the longest
	+message that can be transmitted via this socket.
	+.El
	+.Bl -tag -width indent
	+.It Va net.netlink.recvspace
	+Default receive buffer for the netlink socket.
	+Note that the socket recvspace has to be least as long as the longest
	+message that can be received from this socket.
	+.El
	+.Sh DEBUGGING
	+Netlink implements per-file debugging with different severities controllable via
	+.Va net.netlink.debug
	+branch.
	+These messages are logged in the kernel message buffer and can be seen in
	+.Xr dmesg 8
	+.
	+The following severity levels are defined:
	+.Bl -tag -width indent
	+.It Dv LOG_DEBUG(7)
	+Rare events or per-socket errors are reported here.
	+This is the default level, not impacting production performance.
	+.It Dv LOG_DEBUG2(8)
	+Socket events such as groups memberships, privilege checks, commands and dumps
	+are logged.
	+This level does not incur significant performance overhead.
	+.It Dv LOG_DEBUG9(9)
	+All socket events, each dumped or modified entities are logged.
	+Turning it on may result in significant performance overhead.
	+.El
	+.Sh ERRORS
	+Netlink reports operation results, including errors and error metadata, by
	+sending a
	+.Dv NLMSG_ERROR
	+message for each request message.
	+The following errors can be returned:
	+.Bl -tag -width Er
	+.It Bq Er EPERM
	+when the current privileges are insufficient to perform the required operation;
	+.It Bo Er ENOBUFS Bc or Bo Er ENOMEM Bc
	+when the system runs out of memory for
	+an internal data structure;
	+.It Bq Er ENOTSUP
	+when the requested command is not supported by the family or
	+the family is not supported;
	+.It Bq Er EINVAL
	+when some necessary TLVs are missing or invalid, detailed info
	+may be provided in NLMSGERR_ATTR_MSG and NLMSGERR_ATTR_OFFS TLVs;
	+.It Bq Er ENOENT
	+when trying to delete a non-existent object.
	+.Pp
	+Additionally, a socket operation itself may fail with one of the errors
	+specified in
	+.Xr socket 2
	+,
	+.Xr recv 2
	+or
	+.Xr send 2
	+.
	+.El
	+.Sh SEE ALSO
	+.Xr genetrlink 4 ,
	+.Xr rtnetlink 4
	+.Rs
	+.%A "J. Salim"
	+.%A "H. Khosravi"
	+.%A "A. Kleen"
	+.%A "A. Kuznetsov"
	+.%T "Linux Netlink as an IP Services Protocol"
	+.%O "RFC 3549"
	+.Re
	+.Sh HISTORY
	+The netlink protocol appeared in
	+.Fx 14.0 .
	+.Sh AUTHORS
	+The netlink implementation was written by
	+.An -nosplit
	+.An Alexander Chernikov Aq Mt melifaro@FreeBSD.org .
	+It was derived from the Summer of Code 2021 project by
	+.An Ng Peng Nam Sean .
	diff --git a/share/man/man4/rtnetlink.4 b/share/man/man4/rtnetlink.4
	new file mode 100644
	--- /dev/null
	+++ b/share/man/man4/rtnetlink.4
	@@ -0,0 +1,177 @@
	+.\"
	+.\" Copyright (C) 2022 Alexander Chernikov <melifaro@FreeBSD.org>.
	+.\"
	+.\" Redistribution and use in source and binary forms, with or without
	+.\" modification, are permitted provided that the following conditions
	+.\" are met:
	+.\" 1. Redistributions of source code must retain the above copyright
	+.\" notice, this list of conditions and the following disclaimer.
	+.\" 2. Redistributions in binary form must reproduce the above copyright
	+.\" notice, this list of conditions and the following disclaimer in the
	+.\" documentation and/or other materials provided with the distribution.
	+.\"
	+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+.\" SUCH DAMAGE.
	+.\"
	+.\" $FreeBSD$
	+.\"
	+.Dd September 30, 2022
	+.Dt RTNETLINK 4
	+.Os
	+.Sh NAME
	+.Nm RTNetlink
	+.Nd Network configuration-specific Netlink family
	+.Sh SYNOPSIS
	+.In netlink/netlink.h
	+.In netlink/netlink_route.h
	+.Ft int
	+.Fn socket AF_NETLINK SOCK_DGRAM NETLINK_ROUTE
	+.Sh DESCRIPTION
	+The
	+.Dv NETLINK_ROUTE
	+family is intended to be the primary configuration mechanism for all
	+network-related tasks.
	+Currently it supports configuring interfaces, interface addresses, routes,
	+nexthops and arp/ndp neighbors.
	+.Sh ROUTES
	+All route configuration messages share the common header:
	+.Bd -literal
	+struct rtmsg {
	+ unsigned char rtm_family; /* address family */
	+ unsigned char rtm_dst_len; /* Prefix length */
	+ unsigned char rtm_src_len; /* Deprecated, set to 0 */
	+ unsigned char rtm_tos; /* Type of service (not used) */
	+ unsigned char rtm_table; /* deprecated, set to 0 */
	+ unsigned char rtm_protocol; /* Routing protocol id (RTPROT_) */
	+ unsigned char rtm_scope; /* Route distance (RT_SCOPE_) */
	+ unsigned char rtm_type; /* Route type (RTN_) */
	+ unsigned rtm_flags; /* Route flags (not supported) */
	+};
	+.Ed
	+.Pp
	+The
	+.Fa rtm_family
	+specifies the route family to be operated on.
	+Currently,
	+.Dv AF_INET6
	+and
	+.Dv AF_INET6
	+are the only supported families.
	+Route prefix length is stored in
	+.Fa rtm_dst_len
	+.
	+The caller should set the originator identity (any of
	+.Dv RTPROT_
	+values) in
	+.Fa rtm_protocol
	+.
	+It is useful for user and for the application itself, allowing for easy
	+identification of self-originated routes.
	+Route scope has to be set via
	+.Fa rtm_scope
	+field.
	+The supported values are:
	+.Bd -literal -offset indent -compact
	+RT_SCOPE_UNIVERSE Global scope
	+RT_SCOPE_LINK Link scope
	+.Ed
	+.Pp
	+Route type needs to be set.
	+The defined values are:
	+.Bd -literal -offset indent -compact
	+RTN_UNICAST Unicast route
	+RTN_MULTICAST Multicast route
	+RTN_BLACKHOLE Drops traffic towards destination
	+RTN_PROHIBIT Drops traffic and sends reject
	+.Ed
	+.Pp
	+The following messages are supported:
	+.Ss RTM_NEWROUTE
	+Adds a new route.
	+All NL flags are supported.
	+Extending multipath route requires NLM_F_APPEND flag.
	+.Ss RTM_DELROUTE
	+Tries to delete the route.
	+Route is specified using combination of
	+.Dv RTA_DST
	+TLV and
	+.Fa rtm_dst_len
	+.
	+.Ss RTM_GETROUTE
	+Fetches a single route or all routes in the table, depending on
	+.Dv NLM_F_DUMP flag
	+.
	+Each route is reported as
	+.Dv RTM_NEWROUTE
	+message.
	+.Ss TLVs
	+.Ss Groups
	+The following groups are defined:
	+.Bd -literal -offset indent -compact
	+RTNLGRP_IPV4_ROUTE Notifies on IPv4 route arrival/removal/change
	+RTNLGRP_IPV6_ROUTE Notifies on IPv6 route arrival/removal/change
	+.Ed
	+.Sh NEXTHOPS
	+.Ss RTM_NEWNEXTHOP
	+.Ss RTM_DELNEXTHOP
	+.Ss RTM_GETNEXTHOP
	+.Ss TLVs
	+.Ss Groups
	+The following groups are defined:
	+.Bd -literal -offset indent -compact
	+RTNLGRP_NEXTHOP Notifies on nexthop/groups arrival/removal/change
	+.Ed
	+.Sh INTERFACES
	+.Ss RTM_NEWLINK
	+.Ss RTM_DELLINK
	+.Ss RTM_GETLINK
	+.Ss TLVs
	+.Ss Groups
	+The following groups are defined:
	+.Bd -literal -offset indent -compact
	+RTNLGRP_LINK Notifies on interface arrival/removal/change
	+.Ed
	+.Sh INTERFACE ADDRESSES
	+.Ss RTM_NEWADDR
	+.Ss RTM_DELADDR
	+.Ss RTM_GETADDR
	+.Ss TLVs
	+.Ss Groups
	+The following groups are defined:
	+.Bd -literal -offset indent -compact
	+RTNLGRP_IPV4_IFADDR Notifies on IPv4 ifaddr arrival/removal/change
	+RTNLGRP_IPV6_IFADDR Notifies on IPv6 ifaddr arrival/removal/change
	+.Ed
	+.Sh NEIGHBORS
	+.Ss RTM_NEWNEIGH
	+.Ss RTM_DELNEIGH
	+.Ss RTM_GETNEIGH
	+.Ss TLVs
	+.Ss Groups
	+The following groups are defined:
	+.Bd -literal -offset indent -compact
	+RTNLGRP_NEIGH Notifies on ARP/NDP neighbour arrival/removal/change
	+.Ed
	+.Sh SEE ALSO
	+.Xr netlink 4 ,
	+.Xr route 4
	+.Sh HISTORY
	+The
	+.Dv NETLINK_ROUTE
	+protocol family appeared in
	+.Fx 14.0 .
	+.Sh AUTHORS
	+The netlink implementation was written by
	+.An -nosplit
	+.An Alexander Chernikov Aq Mt melifaro@FreeBSD.org .
	+It was derived from the Summer of Code 2021 project by
	+.An Ng Peng Nam Sean .
	diff --git a/sys/modules/Makefile b/sys/modules/Makefile
	--- a/sys/modules/Makefile
	+++ b/sys/modules/Makefile
	@@ -266,6 +266,7 @@
	my \
	${_nctgpio} \
	${_neta} \
	+ netlink \
	${_netgraph} \
	${_nfe} \
	nfscl \
	diff --git a/sys/modules/netlink/Makefile b/sys/modules/netlink/Makefile
	new file mode 100644
	--- /dev/null
	+++ b/sys/modules/netlink/Makefile
	@@ -0,0 +1,17 @@
	+.PATH: ${SRCTOP}/sys/netlink
	+KMOD= netlink
	+
	+SRCS = netlink_module.c netlink_domain.c netlink_io.c \
	+ netlink_message_parser.c netlink_message_writer.c netlink_generic.c \
	+ netlink_route.c route/iface.c route/iface_drivers.c route/neigh.c \
	+ route/nexthop.c route/route.c
	+
	+EXPORT_SYMS=
	+EXPORT_SYMS+= nlmsg_get_chain_writer
	+EXPORT_SYMS+= nlmsg_refill_buffer
	+EXPORT_SYMS+= nlmsg_end
	+EXPORT_SYMS+= nlmsg_flush
	+
	+EXPORT_SYMS= YES
	+
	+.include <bsd.kmod.mk>
	diff --git a/sys/net/route.c b/sys/net/route.c
	--- a/sys/net/route.c
	+++ b/sys/net/route.c
	@@ -694,3 +694,14 @@

	return (rtsock_routemsg_info(cmd, info, fibnum));
	}
	+
	+/* Netlink-related callbacks needed to glue rtsock, netlink and linuxolator */
	+static void
	+ignore_route_event(uint32_t fibnum, const struct rib_cmd_info *rc)
	+{
	+}
	+static struct rtbridge ignore_cb = { .route_f = ignore_route_event };
	+
	+void linux_netlink_p = NULL; / Callback pointer for Linux translator functions */
	+struct rtbridge *rtsock_callback_p = &ignore_cb;
	+struct rtbridge *netlink_callback_p = &ignore_cb;
	diff --git a/sys/net/route/route_ctl.h b/sys/net/route/route_ctl.h
	--- a/sys/net/route/route_ctl.h
	+++ b/sys/net/route/route_ctl.h
	@@ -189,4 +189,11 @@
	void rib_notify(struct rib_head *rnh, enum rib_subscription_type type,
	struct rib_cmd_info *rc);

	+/* Event bridge */
	+typedef void route_event_f(uint32_t fibnum, const struct rib_cmd_info *rc);
	+struct rtbridge{
	+ route_event_f *route_f;
	+};
	+extern struct rtbridge *rtsock_callback_p;
	+extern struct rtbridge *netlink_callback_p;
	#endif
	diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c
	--- a/sys/net/rtsock.c
	+++ b/sys/net/rtsock.c
	@@ -219,6 +219,7 @@
	int rtm_errno);
	static bool can_export_rte(struct ucred *td_ucred, bool rt_is_host,
	const struct sockaddr *rt_dst);
	+static void rtsock_notify_event(uint32_t fibnum, const struct rib_cmd_info *rc);

	static struct netisr_handler rtsock_nh = {
	.nh_name = "rtsock",
	@@ -274,6 +275,45 @@
	vnet_rts_uninit, 0);
	#endif

	+static void
	+report_route_event(const struct rib_cmd_info rc, void _cbdata)
	+{
	+ uint32_t fibnum = (uint32_t)(uintptr_t)_cbdata;
	+ struct nhop_object *nh;
	+
	+ nh = rc->rc_cmd == RTM_DELETE ? rc->rc_nh_old : rc->rc_nh_new;
	+ rt_routemsg(rc->rc_cmd, rc->rc_rt, nh, fibnum);
	+}
	+
	+static void
	+rts_handle_route_event(uint32_t fibnum, const struct rib_cmd_info *rc)
	+{
	+#ifdef ROUTE_MPATH
	+ if ((rc->rc_nh_new && NH_IS_NHGRP(rc->rc_nh_new)) \|\|
	+ (rc->rc_nh_old && NH_IS_NHGRP(rc->rc_nh_old))) {
	+ rib_decompose_notification(rc, report_route_event,
	+ (void *)(uintptr_t)fibnum);
	+ } else
	+#endif
	+ report_route_event(rc, (void *)(uintptr_t)fibnum);
	+}
	+static struct rtbridge rtsbridge = { .route_f = rts_handle_route_event };
	+static struct rtbridge *rtsbridge_orig_p;
	+
	+static void
	+rtsock_notify_event(uint32_t fibnum, const struct rib_cmd_info *rc)
	+{
	+ netlink_callback_p->route_f(fibnum, rc);
	+}
	+
	+static void
	+rtsock_init(void)
	+{
	+ rtsbridge_orig_p = rtsock_callback_p;
	+ rtsock_callback_p = &rtsbridge;
	+}
	+SYSINIT(rtsock_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, rtsock_init, NULL);
	+
	static void
	rts_handle_ifnet_arrival(void arg __unused, struct ifnet ifp)
	{
	@@ -1074,6 +1114,7 @@
	}
	error = rib_action(fibnum, rtm->rtm_type, &info, &rc);
	if (error == 0) {
	+ rtsock_notify_event(fibnum, &rc);
	#ifdef ROUTE_MPATH
	if (NH_IS_NHGRP(rc.rc_nh_new) \|\|
	(rc.rc_nh_old && NH_IS_NHGRP(rc.rc_nh_old))) {
	@@ -1095,6 +1136,7 @@
	case RTM_DELETE:
	error = rib_action(fibnum, RTM_DELETE, &info, &rc);
	if (error == 0) {
	+ rtsock_notify_event(fibnum, &rc);
	#ifdef ROUTE_MPATH
	if (NH_IS_NHGRP(rc.rc_nh_old) \|\|
	(rc.rc_nh_new && NH_IS_NHGRP(rc.rc_nh_new))) {
	diff --git a/sys/netlink/netlink.h b/sys/netlink/netlink.h
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/netlink.h
	@@ -0,0 +1,257 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2021 Ng Peng Nam Sean
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ *
	+ * Copyright (C) The Internet Society (2003). All Rights Reserved.
	+ *
	+ * This document and translations of it may be copied and furnished to
	+ * others, and derivative works that comment on or otherwise explain it
	+ * or assist in its implementation may be prepared, copied, published
	+ * and distributed, in whole or in part, without restriction of any
	+ * kind, provided that the above copyright notice and this paragraph are
	+ * included on all such copies and derivative works. However, this
	+ * document itself may not be modified in any way, such as by removing
	+ * the copyright notice or references to the Internet Society or other
	+ * Internet organizations, except as needed for the purpose of
	+ * developing Internet standards in which case the procedures for
	+ * copyrights defined in the Internet Standards process must be
	+ * followed, or as required to translate it into languages other than
	+ * English.
	+ *
	+ * The limited permissions granted above are perpetual and will not be
	+ * revoked by the Internet Society or its successors or assignees.
	+ *
	+ * This document and the information contained herein is provided on an
	+ * "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
	+ * TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
	+ * BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
	+ * HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
	+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
	+
	+ */
	+
	+/*
	+ * This file contains structures and constants for RFC 3549 (Netlink)
	+ * protocol. Some values have been taken from Linux implementation.
	+ */
	+
	+#ifndef _NETLINK_NETLINK_H_
	+#define _NETLINK_NETLINK_H_
	+
	+#include <sys/types.h>
	+#include <sys/socket.h>
	+
	+struct sockaddr_nl {
	+ uint8_t nl_len; /* sizeof(sockaddr_nl) */
	+ sa_family_t nl_family; /* netlink family */
	+ uint16_t nl_pad; /* reserved, set to 0 */
	+ uint32_t nl_pid; /* desired port ID, 0 for auto-select */
	+ uint32_t nl_groups; /* multicast groups mask to bind to */
	+};
	+
	+#define SOL_NETLINK 270
	+
	+/* Netlink socket options */
	+#define NETLINK_ADD_MEMBERSHIP 1 /* Subscribe for the specified group notifications */
	+#define NETLINK_DROP_MEMBERSHIP 2 /* Unsubscribe from the specified group */
	+#define NETLINK_PKTINFO 3 /* XXX: not supported */
	+#define NETLINK_BROADCAST_ERROR 4 /* XXX: not supported */
	+#define NETLINK_NO_ENOBUFS 5 /* XXX: not supported */
	+#define NETLINK_RX_RING 6 /* XXX: not supported */
	+#define NETLINK_TX_RING 7 /* XXX: not supported */
	+#define NETLINK_LISTEN_ALL_NSID 8 /* XXX: not supported */
	+
	+#define NETLINK_LIST_MEMBERSHIPS 9
	+#define NETLINK_CAP_ACK 10 /* Send only original message header in the reply */
	+#define NETLINK_EXT_ACK 11 /* Ack support for receiving additional TLVs in ack */
	+#define NETLINK_GET_STRICT_CHK 12 /* Strict header checking */
	+
	+
	+/*
	+ * RFC 3549, 2.3.2 Netlink Message Header
	+ */
	+struct nlmsghdr {
	+ uint32_t nlmsg_len; /* Length of message including header */
	+ uint16_t nlmsg_type; /* Message type identifier */
	+ uint16_t nlmsg_flags; /* Flags (NLM_F_) */
	+ uint32_t nlmsg_seq; /* Sequence number */
	+ uint32_t nlmsg_pid; /* Sending process port ID */
	+};
	+
	+/*
	+ * RFC 3549, 2.3.2 standard flag bits (nlmsg_flags)
	+ */
	+#define NLM_F_REQUEST 0x01 /* Indicateds request to kernel */
	+#define NLM_F_MULTI 0x02 /* Message is part of a group terminated by NLMSG_DONE msg */
	+#define NLM_F_ACK 0x04 /* Reply with ack message containing resulting error code */
	+#define NLM_F_ECHO 0x08 /* (not supported) Echo this request back */
	+#define NLM_F_DUMP_INTR 0x10 /* Dump was inconsistent due to sequence change */
	+#define NLM_F_DUMP_FILTERED 0x20 /* Dump was filtered as requested */
	+
	+/*
	+ * RFC 3549, 2.3.2 Additional flag bits for GET requests
	+ */
	+#define NLM_F_ROOT 0x100 /* Return the complete table */
	+#define NLM_F_MATCH 0x200 /* Return all entries matching criteria */
	+#define NLM_F_ATOMIC 0x400 /* Return an atomic snapshot (ignored) */
	+#define NLM_F_DUMP (NLM_F_ROOT \| NLM_F_MATCH)
	+
	+/*
	+ * RFC 3549, 2.3.2 Additional flag bits for NEW requests
	+ */
	+#define NLM_F_REPLACE 0x100 /* Replace existing matching config object */
	+#define NLM_F_EXCL 0x200 /* Don't replace the object if exists */
	+#define NLM_F_CREATE 0x400 /* Create if it does not exist */
	+#define NLM_F_APPEND 0x800 /* Add to end of list */
	+
	+/* Modifiers to DELETE requests */
	+#define NLM_F_NONREC 0x100 /* Do not delete recursively */
	+
	+/* Flags for ACK message */
	+#define NLM_F_CAPPED 0x100 /* request was capped */
	+#define NLM_F_ACK_TLVS 0x200 /* extended ACK TVLs were included */
	+
	+/*
	+ * RFC 3549, 2.3.2 standard message types (nlmsg_type).
	+ */
	+#define NLMSG_NOOP 0x1 /* Message is ignored. */
	+#define NLMSG_ERROR 0x2 /* reply error code reporting */
	+#define NLMSG_DONE 0x3 /* Message terminates a multipart message. */
	+#define NLMSG_OVERRUN 0x4 /* overrun detected, data is lost */
	+
	+#define NLMSG_MIN_TYPE 0x10 /* < 0x10: reserved control messages */
	+
	+/*
	+ * Defition of numbers assigned to the netlink subsystems.
	+ */
	+#define NETLINK_ROUTE 0 /* Routing/device hook */
	+#define NETLINK_UNUSED 1 /* not supported */
	+#define NETLINK_USERSOCK 2 /* not supported */
	+#define NETLINK_FIREWALL 3 /* not supported */
	+#define NETLINK_SOCK_DIAG 4 /* not supported */
	+#define NETLINK_NFLOG 5 /* not supported */
	+#define NETLINK_XFRM 6 /* (not supported) PF_SETKEY */
	+#define NETLINK_SELINUX 7 /* not supported */
	+#define NETLINK_ISCSI 8 /* not supported */
	+#define NETLINK_AUDIT 9 /* not supported */
	+#define NETLINK_FIB_LOOKUP 10 /* not supported */
	+#define NETLINK_CONNECTOR 11 /* not supported */
	+#define NETLINK_NETFILTER 12 /* not supported */
	+#define NETLINK_IP6_FW 13 /* not supported */
	+#define NETLINK_DNRTMSG 14 /* not supported */
	+#define NETLINK_KOBJECT_UEVENT 15 /* not supported */
	+#define NETLINK_GENERIC 16 /* Generic netlink (dynamic families) */
	+
	+/*
	+ * RFC 3549, 2.3.2.2 The ACK Netlink Message
	+ */
	+struct nlmsgerr {
	+ int error;
	+ struct nlmsghdr msg;
	+};
	+
	+enum nlmsgerr_attrs {
	+ NLMSGERR_ATTR_UNUSED,
	+ NLMSGERR_ATTR_MSG = 1, /* string, error message */
	+ NLMSGERR_ATTR_OFFS = 2, /* u32, offset of the invalid attr from nl header */
	+ NLMSGERR_ATTR_COOKIE = 3, /* binary, data to pass to userland */
	+ NLMSGERR_ATTR_POLICY = 4, /* not supported */
	+ __NLMSGERR_ATTR_MAX,
	+ NLMSGERR_ATTR_MAX = __NLMSGERR_ATTR_MAX - 1
	+};
	+
	+
	+#ifndef roundup2
	+#define roundup2(x, y) (((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */
	+#endif
	+#define NL_ITEM_ALIGN_SIZE sizeof(uint32_t)
	+#define NL_ITEM_ALIGN(_len) roundup2(_len, NL_ITEM_ALIGN_SIZE)
	+#define NL_ITEM_DATA(_ptr, _off) ((void )((char )(_ptr) + _off))
	+#define NL_ITEM_DATA_CONST(_ptr, _off) ((const void )((const char )(_ptr) + _off))
	+
	+#define NL_ITEM_OK(_ptr, _len, _hlen, _LEN_M) \
	+ ((_len) >= _hlen && _LEN_M(_ptr) >= _hlen && _LEN_M(_ptr) <= (_len))
	+#define NL_ITEM_NEXT(_ptr, _LEN_M) ((typeof(_ptr))((char *)(_ptr) + _LEN_M(_ptr)))
	+#define NL_ITEM_ITER(_ptr, _len, _LEN_MACRO) \
	+ ((_len) -= _LEN_MACRO(_ptr), NL_ITEM_NEXT(_ptr, _LEN_MACRO))
	+
	+
	+#ifndef _KERNEL
	+/* part of netlink(3) API */
	+#define NLMSG_ALIGNTO NL_ITEM_ALIGN_SIZE
	+#define NLMSG_ALIGN(_len) NL_ITEM_ALIGN(_len)
	+#define NLMSG_HDRLEN ((int)sizeof(struct nlmsghdr))
	+#define NLMSG_LENGTH(_len) ((_len) + NLMSG_HDRLEN)
	+#define NLMSG_SPACE(len) NLMSG_ALIGN(NLMSG_LENGTH(_len))
	+#define NLMSG_DATA(_hdr) NL_ITEM_DATA(_hdr, NLMSG_HDRLEN)
	+#define _NLMSG_LEN(_hdr) ((int)(_hdr)->nlmsg_len)
	+#define _NLMSG_ALIGNED_LEN(_hdr) NLMSG_ALIGN(_NLMSG_LEN(_hdr))
	+#define NLMSG_OK(_hdr, _len) NL_ITEM_OK(_hdr, _len, NLMSG_HDRLEN, _NLMSG_LEN)
	+#define NLMSG_PAYLOAD(_hdr,_len) (_NLMSG_LEN(_hdr) - NLMSG_SPACE((_len)))
	+#define NLMSG_NEXT(_hdr, _len) NL_ITEM_ITER(_hdr, _len, _NLMSG_ALIGNED_LEN)
	+
	+#else
	+#define NLMSG_ALIGNTO 4U
	+#define NLMSG_ALIGN(len) (((len) + NLMSG_ALIGNTO - 1) & ~(NLMSG_ALIGNTO - 1))
	+#define NLMSG_HDRLEN ((int)NLMSG_ALIGN(sizeof(struct nlmsghdr)))
	+#endif
	+
	+/*
	+ * Base netlink attribute TLV header.
	+ */
	+struct nlattr {
	+ uint16_t nla_len; /* Total attribute length */
	+ uint16_t nla_type; /* Attribute type */
	+};
	+
	+/*
	+ *
	+ * nl_type field enconding:
	+ *
	+ * 0 1
	+ * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6
	+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	+ * \|N\|O\| Attribute type \|
	+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	+ * N - attribute contains other attributes (mostly unused)
	+ * O - encoded in network byte order (mostly unused)
	+ * Note: N & O are mutually exclusive
	+ *
	+ * Note: attribute type value scope normally is either parent attribute
	+ * or the message/message group.
	+ */
	+
	+#define NLA_F_NESTED (1 << 15)
	+#define NLA_F_NET_BYTEORDER (1 << 14)
	+#define NLA_TYPE_MASK ~(NLA_F_NESTED \| NLA_F_NET_BYTEORDER)
	+
	+#ifndef _KERNEL
	+#define NLA_ALIGNTO NL_ITEM_ALIGN_SIZE
	+#define NLA_ALIGN(_len) NL_ITEM_ALIGN(_len)
	+#define NLA_HDRLEN ((int)sizeof(struct nlattr))
	+#endif
	+
	+#endif
	diff --git a/sys/netlink/netlink_ctl.h b/sys/netlink/netlink_ctl.h
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/netlink_ctl.h
	@@ -0,0 +1,102 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+#ifndef _NETLINK_NETLINK_CTL_H_
	+#define _NETLINK_NETLINK_CTL_H_
	+
	+/*
	+ * This file provides headers for the public KPI of the netlink
	+ * subsystem
	+ */
	+
	+MALLOC_DECLARE(M_NETLINK);
	+
	+/*
	+ * Macro for handling attribute TLVs
	+ */
	+#define _roundup2(x, y) (((x)+((y)-1))&(~((y)-1)))
	+
	+#define NETLINK_ALIGN_SIZE sizeof(uint32_t)
	+#define NETLINK_ALIGN(_len) _roundup2(_len, NETLINK_ALIGN_SIZE)
	+
	+#define NLA_ALIGN_SIZE sizeof(uint32_t)
	+#define NLA_ALIGN(_len) _roundup2(_len, NLA_ALIGN_SIZE)
	+#define NLA_HDRLEN ((int)sizeof(struct nlattr))
	+#define NLA_DATA_LEN(_nla) ((int)((_nla)->nla_len - NLA_HDRLEN))
	+#define NLA_DATA(_nla) NL_ITEM_DATA(_nla, NLA_HDRLEN)
	+#define NLA_DATA_CONST(_nla) NL_ITEM_DATA_CONST(_nla, NLA_HDRLEN)
	+#define NLA_TYPE(_nla) ((_nla)->nla_type & 0x3FFF)
	+
	+#ifndef typeof
	+#define typeof __typeof
	+#endif
	+
	+#define NLA_NEXT(_attr) (struct nlattr )((char )_attr + NLA_ALIGN(_attr->nla_len))
	+#define _NLA_END(_start, _len) ((char *)(_start) + (_len))
	+#define NLA_FOREACH(_attr, _start, _len) \
	+ for (typeof(_attr) _end = (typeof(_attr))_NLA_END(_start, _len), _attr = (_start); \
	+ ((char )_attr < (char )_end) && \
	+ ((char )NLA_NEXT(_attr) <= (char )_end); \
	+ _attr = (_len -= NLA_ALIGN(_attr->nla_len), NLA_NEXT(_attr)))
	+
	+#define NL_ARRAY_LEN(_a) (sizeof(_a) / sizeof((_a)[0]))
	+
	+#include <netlink/netlink_message_writer.h>
	+#include <netlink/netlink_message_parser.h>
	+
	+
	+/* Protocol handlers */
	+struct nl_pstate;
	+typedef int (nl_handler_f)(struct nlmsghdr hdr, struct nl_pstate *npt);
	+
	+bool netlink_register_proto(int proto, const char *proto_name, nl_handler_f handler);
	+bool netlink_unregister_proto(int proto);
	+
	+/* Common helpers */
	+bool nl_has_listeners(int netlink_family, uint32_t groups_mask);
	+bool nlp_has_priv(struct nlpcb *nlp, int priv);
	+
	+/* netlink_generic.c */
	+struct genl_cmd {
	+ const char *cmd_name;
	+ nl_handler_f cmd_cb;
	+ uint32_t cmd_flags;
	+ uint32_t cmd_priv;
	+ uint32_t cmd_num;
	+};
	+
	+uint32_t genl_register_family(const char *family_name, size_t hdrsize,
	+ int family_version, int max_attr_idx);
	+bool genl_unregister_family(const char *family_name);
	+bool genl_register_cmds(const char family_name, const struct genl_cmd cmds,
	+ int count);
	+uint32_t genl_register_group(const char family_name, const char group_name);
	+
	+/* Debug */
	+uint32_t nlp_get_pid(const struct nlpcb *nlp);
	+
	+#endif
	diff --git a/sys/netlink/netlink_debug.h b/sys/netlink/netlink_debug.h
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/netlink_debug.h
	@@ -0,0 +1,82 @@
	+/*-
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ * 3. Neither the name of the University nor the names of its contributors
	+ * may be used to endorse or promote products derived from this software
	+ * without specific prior written permission.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ *
	+ * $FreeBSD$
	+ */
	+
	+#ifndef _NETLINK_NETLINK_DEBUG_H_
	+#define _NETLINK_NETLINK_DEBUG_H_
	+
	+#define _DEBUG_SYSCTL_OID _net_netlink_debug
	+#include <net/route/route_debug.h>
	+
	+SYSCTL_DECL(_net_netlink_debug);
	+
	+/*
	+ * Generic debug
	+ * [nl_domain] func_name: debug text
	+ */
	+#define NL_LOG RT_LOG
	+
	+/*
	+ * Logging for events specific for particular process
	+ * Example: [nl_domain] PID 4834 fdump_sa: unsupported family: 45
	+ */
	+#define NL_RAW_PID_LOG(_l, _pid, _fmt, ...) NL_RAW_PID_LOG_##_l(_l, _pid, _fmt, ## __VA_ARGS__)
	+#define _NL_RAW_PID_LOG(_l, _pid, _fmt, ...) if (_DEBUG_PASS_MSG(_l)) { \
	+ _output("[" DEBUG_PREFIX_NAME "] PID %u %s: " _fmt "\n", _pid, __func__, ##__VA_ARGS__); \
	+}
	+
	+#define NLP_LOG(_l, _nlp, _fmt, ...) NL_RAW_PID_LOG_##_l(_l, nlp_get_pid(_nlp), _fmt, ## __VA_ARGS__)
	+
	+#if DEBUG_MAX_LEVEL>=LOG_DEBUG3
	+#define NL_RAW_PID_LOG_LOG_DEBUG3 _NL_RAW_PID_LOG
	+#else
	+#define NL_RAW_PID_LOG_LOG_DEBUG3(_l, _pid, _fmt, ...)
	+#endif
	+#if DEBUG_MAX_LEVEL>=LOG_DEBUG2
	+#define NL_RAW_PID_LOG_LOG_DEBUG2 _NL_RAW_PID_LOG
	+#else
	+#define NL_RAW_PID_LOG_LOG_DEBUG2(_l, _pid, _fmt, ...)
	+#endif
	+#if DEBUG_MAX_LEVEL>=LOG_DEBUG
	+#define NL_RAW_PID_LOG_LOG_DEBUG _NL_RAW_PID_LOG
	+#else
	+#define NL_RAW_PID_LOG_LOG_DEBUG(_l, _pid, _fmt, ...)
	+#endif
	+#if DEBUG_MAX_LEVEL>=LOG_INFO
	+#define NL_RAW_PID_LOG_LOG_INFO _NL_RAW_PID_LOG
	+#else
	+#define NL_RAW_PID_LOG_LOG_INFO(_l, _pid, _fmt, ...)
	+#endif
	+#define NL_RAW_PID_LOG_LOG_NOTICE _NL_RAW_PID_LOG
	+#define NL_RAW_PID_LOG_LOG_ERR _NL_RAW_PID_LOG
	+#define NL_RAW_PID_LOG_LOG_WARNING _NL_RAW_PID_LOG
	+
	+
	+
	+#endif
	diff --git a/sys/netlink/netlink_domain.c b/sys/netlink/netlink_domain.c
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/netlink_domain.c
	@@ -0,0 +1,689 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2021 Ng Peng Nam Sean
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+/*
	+ * This file contains socket and protocol bindings for netlink.
	+ */
	+
	+#include <sys/param.h>
	+#include <sys/malloc.h>
	+#include <sys/lock.h>
	+#include <sys/rmlock.h>
	+#include <sys/domain.h>
	+#include <sys/mbuf.h>
	+#include <sys/protosw.h>
	+#include <sys/ck.h>
	+#include <sys/socket.h>
	+#include <sys/socketvar.h>
	+#include <sys/sysent.h>
	+#include <sys/syslog.h>
	+#include <sys/priv.h> /* priv_check */
	+
	+#include <netlink/netlink.h>
	+#include <netlink/netlink_ctl.h>
	+#include <netlink/netlink_var.h>
	+
	+#define DEBUG_MOD_NAME nl_domain
	+#define DEBUG_MAX_LEVEL LOG_DEBUG3
	+#include <netlink/netlink_debug.h>
	+_DECLARE_DEBUG(LOG_DEBUG);
	+
	+
	+#define NLCTL_TRACKER struct rm_priotracker nl_tracker
	+#define NLCTL_RLOCK(_ctl) rm_rlock(&((_ctl)->ctl_lock), &nl_tracker)
	+#define NLCTL_RUNLOCK(_ctl) rm_runlock(&((_ctl)->ctl_lock), &nl_tracker)
	+
	+#define NLCTL_WLOCK(_ctl) rm_wlock(&((_ctl)->ctl_lock))
	+#define NLCTL_WUNLOCK(_ctl) rm_wunlock(&((_ctl)->ctl_lock))
	+
	+static u_long nl_sendspace = NLSNDQ;
	+SYSCTL_ULONG(_net_netlink, OID_AUTO, sendspace, CTLFLAG_RW, &nl_sendspace, 0,
	+ "Default netlink socket send space");
	+
	+static u_long nl_recvspace = NLSNDQ;
	+SYSCTL_ULONG(_net_netlink, OID_AUTO, recvspace, CTLFLAG_RW, &nl_recvspace, 0,
	+ "Default netlink socket receive space");
	+
	+extern u_long sb_max_adj;
	+static u_long nl_maxsockbuf = 512 * 1024 * 1024; /* 512M, XXX: init based on physmem */
	+
	+uint32_t
	+nlp_get_pid(const struct nlpcb *nlp)
	+{
	+ return (nlp->nl_process_id);
	+}
	+
	+/*
	+ * Looks up a nlpcb struct based on the @portid. Need to claim nlsock_mtx.
	+ * Returns nlpcb pointer if present else NULL
	+ */
	+static struct nlpcb *
	+nl_port_lookup(uint32_t port_id)
	+{
	+ struct nlpcb *nlp;
	+
	+ CK_LIST_FOREACH(nlp, &V_nl_ctl->ctl_port_head, nl_port_next) {
	+ if (nlp->nl_port == port_id)
	+ return (nlp);
	+ }
	+ return (NULL);
	+}
	+
	+static void
	+nl_update_groups_locked(struct nlpcb *nlp, uint64_t nl_groups)
	+{
	+ /* Update group mask */
	+ NL_LOG(LOG_DEBUG2, "socket %p, groups 0x%lX -> 0x%lX",
	+ nlp->nl_socket, nlp->nl_groups, nl_groups);
	+ nlp->nl_groups = nl_groups;
	+}
	+
	+/*
	+ * Broadcasts message @m to the protocol @proto group specified by @group_id
	+ */
	+void
	+nl_send_group(struct mbuf *m, int num_messages, int proto, int group_id)
	+{
	+ struct nlpcb *nlp_last = NULL;
	+ struct nlpcb *nlp;
	+ NLCTL_TRACKER;
	+
	+ IF_DEBUG_LEVEL(LOG_DEBUG2) {
	+ struct nlmsghdr hdr = mtod(m, struct nlmsghdr );
	+ NL_LOG(LOG_DEBUG2, "MCAST mbuf len %u msg type %d len %u to group %d/%d",
	+ m->m_len, hdr->nlmsg_type, hdr->nlmsg_len, proto, group_id);
	+ }
	+
	+ struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
	+ if (__predict_false(ctl == NULL)) {
	+ /*
	+ * Can be the case when notification is sent within VNET
	+ * which doesn't have any netlink sockets.
	+ */
	+ m_freem(m);
	+ return;
	+ }
	+
	+ NLCTL_RLOCK(ctl);
	+
	+ int io_flags = NL_IOF_UNTRANSLATED;
	+ uint64_t groups_mask = 1 << ((uint64_t)group_id - 1);
	+
	+ CK_LIST_FOREACH(nlp, &ctl->ctl_pcb_head, nl_next) {
	+ if (nlp->nl_groups & groups_mask && nlp->nl_proto == proto) {
	+ if (nlp_last != NULL) {
	+ struct mbuf *m_copy;
	+ m_copy = m_copym(m, 0, M_COPYALL, M_NOWAIT);
	+ if (m_copy != NULL)
	+ nl_send_one(m_copy, nlp_last, num_messages, io_flags);
	+ else {
	+ NLP_LOCK(nlp_last);
	+ if (nlp_last->nl_socket != NULL)
	+ sorwakeup(nlp_last->nl_socket);
	+ NLP_UNLOCK(nlp_last);
	+ }
	+ }
	+ nlp_last = nlp;
	+ }
	+ }
	+ if (nlp_last != NULL)
	+ nl_send_one(m, nlp_last, num_messages, io_flags);
	+ else
	+ m_freem(m);
	+
	+ NLCTL_RUNLOCK(ctl);
	+}
	+
	+bool
	+nl_has_listeners(int netlink_family, uint32_t groups_mask)
	+{
	+ return (V_nl_ctl != NULL);
	+}
	+
	+bool
	+nlp_has_priv(struct nlpcb *nlp, int priv)
	+{
	+ return (priv_check_cred(nlp->nl_cred, priv) == 0);
	+}
	+
	+static uint32_t
	+nl_find_port() {
	+ /*
	+ * app can open multiple netlink sockets.
	+ * Start with current pid, if already taken,
	+ * try random numbers in 65k..256k+65k space,
	+ * avoiding clash with pids.
	+ */
	+ if (nl_port_lookup(curproc->p_pid) == NULL)
	+ return (curproc->p_pid);
	+ for (int i = 0; i < 16; i++) {
	+ uint32_t nl_port = (arc4random() % 65536) + 65536 * 4;
	+ if (nl_port_lookup(nl_port) == 0)
	+ return (nl_port);
	+ NL_LOG(LOG_DEBUG3, "tried %u\n", nl_port);
	+ }
	+ return (curproc->p_pid);
	+}
	+
	+static int
	+nl_bind_locked(struct nlpcb nlp, struct sockaddr_nl snl)
	+{
	+ if (nlp->nl_bound) {
	+ if (nlp->nl_port != snl->nl_pid) {
	+ NL_LOG(LOG_DEBUG,
	+ "bind() failed: program pid %d "
	+ "is different from provided pid %d",
	+ nlp->nl_port, snl->nl_pid);
	+ return (EINVAL); // XXX: better error
	+ }
	+ } else {
	+ if (snl->nl_pid == 0)
	+ snl->nl_pid = nl_find_port();
	+ if (nl_port_lookup(snl->nl_pid) != NULL)
	+ return (EADDRINUSE);
	+ nlp->nl_port = snl->nl_pid;
	+ nlp->nl_bound = true;
	+ CK_LIST_INSERT_HEAD(&V_nl_ctl->ctl_port_head, nlp, nl_port_next);
	+ }
	+ nl_update_groups_locked(nlp, snl->nl_groups);
	+
	+ return (0);
	+}
	+
	+static int
	+nl_pru_attach(struct socket so, int proto, struct thread td)
	+{
	+ struct nlpcb *nlp;
	+ int error;
	+
	+ if (__predict_false(netlink_unloading != 0))
	+ return (EAFNOSUPPORT);
	+
	+ error = nl_verify_proto(proto);
	+ if (error != 0)
	+ return (error);
	+
	+ bool is_linux = SV_PROC_ABI(td->td_proc) == SV_ABI_LINUX;
	+ NL_LOG(LOG_DEBUG2, "socket %p, %sPID %d: attaching socket to %s",
	+ so, is_linux ? "(linux) " : "", curproc->p_pid,
	+ nl_get_proto_name(proto));
	+
	+ /* Create per-VNET state on first socket init */
	+ struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
	+ if (ctl == NULL)
	+ ctl = vnet_nl_ctl_init();
	+ KASSERT(V_nl_ctl != NULL, ("nl_attach: vnet_sock_init() failed"));
	+
	+ MPASS(sotonlpcb(so) == NULL);
	+
	+ nlp = malloc(sizeof(struct nlpcb), M_PCB, M_WAITOK \| M_ZERO);
	+ error = soreserve(so, nl_sendspace, nl_recvspace);
	+ if (error != 0) {
	+ free(nlp, M_PCB);
	+ return (error);
	+ }
	+ so->so_pcb = nlp;
	+ nlp->nl_socket = so;
	+ /* Copy so_cred to avoid having socket_var.h in every header */
	+ nlp->nl_cred = so->so_cred;
	+ nlp->nl_proto = proto;
	+ nlp->nl_process_id = curproc->p_pid;
	+ nlp->nl_linux = is_linux;
	+ nlp->nl_active = true;
	+ NLP_LOCK_INIT(nlp);
	+ refcount_init(&nlp->nl_refcount, 1);
	+ nl_init_io(nlp);
	+
	+ nlp->nl_taskqueue = taskqueue_create("netlink_socket", M_WAITOK,
	+ taskqueue_thread_enqueue, &nlp->nl_taskqueue);
	+ TASK_INIT(&nlp->nl_task, 0, nl_taskqueue_handler, nlp);
	+ taskqueue_start_threads(&nlp->nl_taskqueue, 1, PWAIT,
	+ "netlink_socket (PID %u)", nlp->nl_process_id);
	+
	+ NLCTL_WLOCK(ctl);
	+ /* XXX: check ctl is still alive */
	+ CK_LIST_INSERT_HEAD(&ctl->ctl_pcb_head, nlp, nl_next);
	+ NLCTL_WUNLOCK(ctl);
	+
	+ soisconnected(so);
	+
	+ return (0);
	+}
	+
	+static void
	+nl_pru_abort(struct socket *so)
	+{
	+ NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
	+ MPASS(sotonlpcb(so) != NULL);
	+ soisdisconnected(so);
	+}
	+
	+static int
	+nl_pru_bind(struct socket so, struct sockaddr sa, struct thread *td)
	+{
	+ struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
	+ struct nlpcb *nlp = sotonlpcb(so);
	+ struct sockaddr_nl snl = (struct sockaddr_nl )sa;
	+ int error;
	+
	+ NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
	+ if (snl->nl_len != sizeof(*snl)) {
	+ NL_LOG(LOG_DEBUG, "socket %p, wrong sizeof(), ignoring bind()", so);
	+ return (EINVAL);
	+ }
	+
	+
	+ NLCTL_WLOCK(ctl);
	+ NLP_LOCK(nlp);
	+ error = nl_bind_locked(nlp, snl);
	+ NLP_UNLOCK(nlp);
	+ NLCTL_WUNLOCK(ctl);
	+ NL_LOG(LOG_DEBUG2, "socket %p, bind() to %u, groups %u, error %d", so,
	+ snl->nl_pid, snl->nl_groups, error);
	+
	+ return (error);
	+}
	+
	+
	+static int
	+nl_assign_port(struct nlpcb *nlp, uint32_t port_id)
	+{
	+ struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
	+ struct sockaddr_nl snl = {
	+ .nl_pid = port_id,
	+ };
	+ int error;
	+
	+ NLCTL_WLOCK(ctl);
	+ NLP_LOCK(nlp);
	+ snl.nl_groups = nlp->nl_groups;
	+ error = nl_bind_locked(nlp, &snl);
	+ NLP_UNLOCK(nlp);
	+ NLCTL_WUNLOCK(ctl);
	+
	+ NL_LOG(LOG_DEBUG3, "socket %p, port assign: %d, error: %d", nlp->nl_socket, port_id, error);
	+ return (error);
	+}
	+
	+/*
	+ * nl_autobind_port binds a unused portid to @nlp
	+ * @nlp: pcb data for the netlink socket
	+ * @candidate_id: first id to consider
	+ */
	+static int
	+nl_autobind_port(struct nlpcb *nlp, uint32_t candidate_id)
	+{
	+ struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
	+ uint32_t port_id = candidate_id;
	+ NLCTL_TRACKER;
	+ bool exist;
	+ int error;
	+
	+ for (int i = 0; i < 10; i++) {
	+ NL_LOG(LOG_DEBUG3, "socket %p, trying to assign port %d", nlp->nl_socket, port_id);
	+ NLCTL_RLOCK(ctl);
	+ exist = nl_port_lookup(port_id) != 0;
	+ NLCTL_RUNLOCK(ctl);
	+ if (!exist) {
	+ error = nl_assign_port(nlp, port_id);
	+ if (error != EADDRINUSE)
	+ break;
	+ }
	+ port_id++;
	+ }
	+ NL_LOG(LOG_DEBUG3, "socket %p, autobind to %d, error: %d", nlp->nl_socket, port_id, error);
	+ return (error);
	+}
	+
	+static int
	+nl_pru_connect(struct socket so, struct sockaddr sa, struct thread *td)
	+{
	+ struct sockaddr_nl snl = (struct sockaddr_nl )sa;
	+ struct nlpcb *nlp;
	+
	+ NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
	+ if (snl->nl_len != sizeof(*snl)) {
	+ NL_LOG(LOG_DEBUG, "socket %p, wrong sizeof(), ignoring bind()", so);
	+ return (EINVAL);
	+ }
	+
	+ nlp = sotonlpcb(so);
	+ if (!nlp->nl_bound) {
	+ int error = nl_autobind_port(nlp, td->td_proc->p_pid);
	+ if (error != 0) {
	+ NL_LOG(LOG_DEBUG, "socket %p, nl_autobind() failed: %d", so, error);
	+ return (error);
	+ }
	+ }
	+ /* XXX: Handle socket flags & multicast */
	+ soisconnected(so);
	+
	+ NL_LOG(LOG_DEBUG2, "socket %p, connect to %u", so, snl->nl_pid);
	+
	+ return (0);
	+}
	+
	+static void
	+destroy_nlpcb(struct nlpcb *nlp)
	+{
	+ NLP_LOCK(nlp);
	+ nl_free_io(nlp);
	+ NLP_LOCK_DESTROY(nlp);
	+ free(nlp, M_PCB);
	+}
	+
	+static void
	+destroy_nlpcb_epoch(epoch_context_t ctx)
	+{
	+ struct nlpcb *nlp;
	+
	+ nlp = __containerof(ctx, struct nlpcb, nl_epoch_ctx);
	+
	+ destroy_nlpcb(nlp);
	+}
	+
	+
	+static void
	+nl_pru_detach(struct socket *so)
	+{
	+ struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
	+ MPASS(sotonlpcb(so) != NULL);
	+ struct nlpcb *nlp;
	+
	+ NL_LOG(LOG_DEBUG2, "detaching socket %p, PID %d", so, curproc->p_pid);
	+ nlp = sotonlpcb(so);
	+
	+ /* Mark as inactive so no new work can be enqueued */
	+ NLP_LOCK(nlp);
	+ bool was_bound = nlp->nl_bound;
	+ nlp->nl_active = false;
	+ NLP_UNLOCK(nlp);
	+
	+ /* Wait till all scheduled work has been completed */
	+ taskqueue_drain_all(nlp->nl_taskqueue);
	+ taskqueue_free(nlp->nl_taskqueue);
	+
	+ NLCTL_WLOCK(ctl);
	+ NLP_LOCK(nlp);
	+ if (was_bound) {
	+ CK_LIST_REMOVE(nlp, nl_port_next);
	+ NL_LOG(LOG_DEBUG3, "socket %p, unlinking bound pid %u", so, nlp->nl_port);
	+ }
	+ CK_LIST_REMOVE(nlp, nl_next);
	+ nlp->nl_socket = NULL;
	+ NLP_UNLOCK(nlp);
	+ NLCTL_WUNLOCK(ctl);
	+
	+ so->so_pcb = NULL;
	+
	+ NL_LOG(LOG_DEBUG3, "socket %p, detached", so);
	+
	+ /* XXX: is delayed free needed? */
	+ epoch_call(net_epoch_preempt, destroy_nlpcb_epoch, &nlp->nl_epoch_ctx);
	+}
	+
	+static int
	+nl_pru_disconnect(struct socket *so)
	+{
	+ NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
	+ MPASS(sotonlpcb(so) != NULL);
	+ return (ENOTCONN);
	+}
	+
	+static int
	+nl_pru_peeraddr(struct socket so, struct sockaddr *sa)
	+{
	+ NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
	+ MPASS(sotonlpcb(so) != NULL);
	+ return (ENOTCONN);
	+}
	+
	+static int
	+nl_pru_shutdown(struct socket *so)
	+{
	+ NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
	+ MPASS(sotonlpcb(so) != NULL);
	+ socantsendmore(so);
	+ return (0);
	+}
	+
	+static int
	+nl_pru_sockaddr(struct socket so, struct sockaddr *sa)
	+{
	+ struct sockaddr_nl *snl;
	+
	+ snl = malloc(sizeof(struct sockaddr_nl), M_SONAME, M_WAITOK \| M_ZERO);
	+ /* TODO: set other fields */
	+ snl->nl_len = sizeof(struct sockaddr_nl);
	+ snl->nl_family = AF_NETLINK;
	+ snl->nl_pid = sotonlpcb(so)->nl_port;
	+ sa = (struct sockaddr )snl;
	+ return (0);
	+}
	+
	+static void
	+nl_pru_close(struct socket *so)
	+{
	+ NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
	+ MPASS(sotonlpcb(so) != NULL);
	+ soisdisconnected(so);
	+}
	+
	+static int
	+nl_pru_output(struct mbuf m, struct socket so, ...)
	+{
	+
	+ if (__predict_false(m == NULL \|\|
	+ ((m->m_len < sizeof(struct nlmsghdr)) &&
	+ (m = m_pullup(m, sizeof(struct nlmsghdr))) == NULL)))
	+ return (ENOBUFS);
	+ MPASS((m->m_flags & M_PKTHDR) != 0);
	+
	+ NL_LOG(LOG_DEBUG3, "sending message to kernel async processing");
	+ nl_receive_async(m, so);
	+ return (0);
	+}
	+
	+
	+static int
	+nl_pru_send(struct socket so, int flags, struct mbuf m, struct sockaddr *sa,
	+ struct mbuf control, struct thread td)
	+{
	+ NL_LOG(LOG_DEBUG2, "sending message to kernel");
	+
	+ if (__predict_false(control != NULL)) {
	+ if (control->m_len) {
	+ m_freem(control);
	+ return (EINVAL);
	+ }
	+ m_freem(control);
	+ }
	+
	+ return (nl_pru_output(m, so));
	+}
	+
	+static int
	+nl_pru_rcvd(struct socket *so, int flags)
	+{
	+ NL_LOG(LOG_DEBUG3, "socket %p, PID %d", so, curproc->p_pid);
	+ MPASS(sotonlpcb(so) != NULL);
	+
	+ nl_on_transmit(sotonlpcb(so));
	+
	+ return (0);
	+}
	+
	+static int
	+nl_getoptflag(int sopt_name)
	+{
	+ switch (sopt_name) {
	+ case NETLINK_CAP_ACK:
	+ return (NLF_CAP_ACK);
	+ case NETLINK_EXT_ACK:
	+ return (NLF_EXT_ACK);
	+ case NETLINK_GET_STRICT_CHK:
	+ return (NLF_STRICT);
	+ }
	+
	+ return (0);
	+}
	+
	+static int
	+nl_ctloutput(struct socket so, struct sockopt sopt)
	+{
	+ struct nl_control *ctl = atomic_load_ptr(&V_nl_ctl);
	+ struct nlpcb *nlp = sotonlpcb(so);
	+ uint32_t flag;
	+ uint64_t groups, group_mask;
	+ int optval, error = 0;
	+ NLCTL_TRACKER;
	+
	+ NL_LOG(LOG_DEBUG2, "%ssockopt(%p, %d)", (sopt->sopt_dir) ? "set" : "get",
	+ so, sopt->sopt_name);
	+
	+ switch (sopt->sopt_dir) {
	+ case SOPT_SET:
	+ switch (sopt->sopt_name) {
	+ case NETLINK_ADD_MEMBERSHIP:
	+ case NETLINK_DROP_MEMBERSHIP:
	+ sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval));
	+ if (optval <= 0 \|\| optval >= 64) {
	+ error = ERANGE;
	+ break;
	+ }
	+ group_mask = (uint64_t)1 << (optval - 1);
	+ NL_LOG(LOG_DEBUG2, "ADD/DEL group %d mask (%lX)", optval, group_mask);
	+
	+ NLCTL_WLOCK(ctl);
	+ if (sopt->sopt_name == NETLINK_ADD_MEMBERSHIP)
	+ groups = nlp->nl_groups \| group_mask;
	+ else
	+ groups = nlp->nl_groups & ~group_mask;
	+ nl_update_groups_locked(nlp, groups);
	+ NLCTL_WUNLOCK(ctl);
	+ break;
	+ case NETLINK_CAP_ACK:
	+ case NETLINK_EXT_ACK:
	+ case NETLINK_GET_STRICT_CHK:
	+ sooptcopyin(sopt, &optval, sizeof(optval), sizeof(optval));
	+
	+ flag = nl_getoptflag(sopt->sopt_name);
	+
	+ NLCTL_WLOCK(ctl);
	+ if (optval != 0)
	+ nlp->nl_flags \|= flag;
	+ else
	+ nlp->nl_flags &= ~flag;
	+ NLCTL_WUNLOCK(ctl);
	+ break;
	+ default:
	+ error = ENOPROTOOPT;
	+ }
	+ break;
	+ case SOPT_GET:
	+ switch (sopt->sopt_name) {
	+ case NETLINK_LIST_MEMBERSHIPS:
	+ NLCTL_RLOCK(ctl);
	+ optval = nlp->nl_groups;
	+ NLCTL_RUNLOCK(ctl);
	+ error = sooptcopyout(sopt, &optval, sizeof(optval));
	+ break;
	+ case NETLINK_CAP_ACK:
	+ case NETLINK_EXT_ACK:
	+ case NETLINK_GET_STRICT_CHK:
	+ NLCTL_RLOCK(ctl);
	+ optval = (nlp->nl_flags & nl_getoptflag(sopt->sopt_name)) != 0;
	+ NLCTL_RUNLOCK(ctl);
	+ error = sooptcopyout(sopt, &optval, sizeof(optval));
	+ break;
	+ default:
	+ error = ENOPROTOOPT;
	+ }
	+ break;
	+ default:
	+ error = ENOPROTOOPT;
	+ }
	+
	+ return (error);
	+}
	+
	+static int
	+nl_setsbopt(struct socket so, struct sockopt sopt)
	+{
	+ int error, optval;
	+ bool result;
	+
	+ if (sopt->sopt_name != SO_RCVBUF)
	+ return (sbsetopt(so, sopt));
	+
	+ /* Allow to override max buffer size in certain conditions */
	+
	+ error = sooptcopyin(sopt, &optval, sizeof optval, sizeof optval);
	+ if (error != 0)
	+ return (error);
	+ NL_LOG(LOG_DEBUG2, "socket %p, PID %d, SO_RCVBUF=%d", so, curproc->p_pid, optval);
	+ if (optval > sb_max_adj) {
	+ if (priv_check(curthread, PRIV_NET_ROUTE) != 0)
	+ return (EPERM);
	+ }
	+
	+ SOCK_RECVBUF_LOCK(so);
	+ result = sbreserve_locked_limit(so, SO_RCV, optval, nl_maxsockbuf, curthread);
	+ SOCK_RECVBUF_UNLOCK(so);
	+
	+ return (result ? 0 : ENOBUFS);
	+}
	+
	+static struct protosw netlinksw = {
	+ .pr_type = SOCK_RAW,
	+ .pr_flags = PR_ATOMIC \| PR_ADDR \| PR_WANTRCVD,
	+ .pr_ctloutput = nl_ctloutput,
	+ .pr_setsbopt = nl_setsbopt,
	+ .pr_abort = nl_pru_abort,
	+ .pr_attach = nl_pru_attach,
	+ .pr_bind = nl_pru_bind,
	+ .pr_connect = nl_pru_connect,
	+ .pr_detach = nl_pru_detach,
	+ .pr_disconnect = nl_pru_disconnect,
	+ .pr_peeraddr = nl_pru_peeraddr,
	+ .pr_send = nl_pru_send,
	+ .pr_rcvd = nl_pru_rcvd,
	+ .pr_shutdown = nl_pru_shutdown,
	+ .pr_sockaddr = nl_pru_sockaddr,
	+ .pr_close = nl_pru_close
	+};
	+
	+static struct domain netlinkdomain = {
	+ .dom_family = PF_NETLINK,
	+ .dom_name = "netlink",
	+ .dom_flags = DOMF_UNLOADABLE,
	+ .dom_nprotosw = 1,
	+ .dom_protosw = { &netlinksw },
	+};
	+
	+DOMAIN_SET(netlink);
	diff --git a/sys/netlink/netlink_generic.h b/sys/netlink/netlink_generic.h
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/netlink_generic.h
	@@ -0,0 +1,112 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+/*
	+ * Generic netlink message header and attributes
	+ */
	+#ifndef _NETLINK_NETLINK_GENERIC_H_
	+#define _NETLINK_NETLINK_GENERIC_H_
	+
	+/* Base header for all of the relevant messages */
	+struct genlmsghdr {
	+ uint8_t cmd; /* CTRL_CMD_ */
	+ uint8_t version; /* ABI version for the cmd */
	+ uint16_t reserved; /* reserved: set to 0 */
	+};
	+#define GENL_HDRLEN NL_ITEM_ALIGN(sizeof(struct genlmsghdr))
	+
	+/* Dynamic family number range, inclusive */
	+#define GENL_MIN_ID NLMSG_MIN_TYPE
	+#define GENL_MAX_ID 1023
	+
	+/* Pre-defined family numbers */
	+#define GENL_ID_CTRL GENL_MIN_ID
	+
	+/* Available commands */
	+enum {
	+ CTRL_CMD_UNSPEC = 0,
	+ CTRL_CMD_NEWFAMILY = 1,
	+ CTRL_CMD_DELFAMILY = 2,
	+ CTRL_CMD_GETFAMILY = 3, /* lists all (or matching) genetlink families */
	+ CTRL_CMD_NEWOPS = 4,
	+ CTRL_CMD_DELOPS = 5,
	+ CTRL_CMD_GETOPS = 6,
	+ CTRL_CMD_NEWMCAST_GRP = 7,
	+ CTRL_CMD_DELMCAST_GRP = 8,
	+ CTRL_CMD_GETMCAST_GRP = 9,
	+ CTRL_CMD_GETPOLICY = 10,
	+ __CTRL_CMD_MAX,
	+};
	+#define CTRL_CMD_MAX (__CTRL_CMD_MAX - 1)
	+
	+/* Generic attributes */
	+enum {
	+ CTRL_ATTR_UNSPEC,
	+ CTRL_ATTR_FAMILY_ID = 1, /* u16, dynamically-assigned ID */
	+ CTRL_ATTR_FAMILY_NAME = 2, /* string, family name */
	+ CTRL_ATTR_VERSION = 3, /* u32, command version */
	+ CTRL_ATTR_HDRSIZE = 4, /* u32, family header size */
	+ CTRL_ATTR_MAXATTR = 5, /* u32, maximum family attr # */
	+ CTRL_ATTR_OPS = 6, /* nested, available operations */
	+ CTRL_ATTR_MCAST_GROUPS = 7,
	+ CTRL_ATTR_POLICY = 8,
	+ CTRL_ATTR_OP_POLICY = 9,
	+ CTRL_ATTR_OP = 10,
	+ __CTRL_ATTR_MAX,
	+};
	+#define CTRL_ATTR_MAX (__CTRL_ATTR_MAX - 1)
	+
	+#define GENL_NAMSIZ 16 /* max family name length including \0 */
	+
	+/* CTRL_ATTR_OPS attributes */
	+enum {
	+ CTRL_ATTR_OP_UNSPEC,
	+ CTRL_ATTR_OP_ID = 1, /* u32, operation # */
	+ CTRL_ATTR_OP_FLAGS = 2, /* u32, flags-based op description */
	+ __CTRL_ATTR_OP_MAX,
	+};
	+#define CTRL_ATTR_OP_MAX (__CTRL_ATTR_OP_MAX - 1)
	+
	+/* CTRL_ATTR_OP_FLAGS values */
	+#define GENL_ADMIN_PERM 0x0001 /* Requires elevated permissions */
	+#define GENL_CMD_CAP_DO 0x0002 /* Operation is a modification request */
	+#define GENL_CMD_CAP_DUMP 0x0004 /* Operation is a get/dump request */
	+#define GENL_CMD_CAP_HASPOL 0x0008 /* Operation has a validation policy */
	+#define GENL_UNS_ADMIN_PERM 0x0010
	+
	+/* CTRL_ATTR_MCAST_GROUPS attributes */
	+enum {
	+ CTRL_ATTR_MCAST_GRP_UNSPEC,
	+ CTRL_ATTR_MCAST_GRP_NAME, /* string, group name */
	+ CTRL_ATTR_MCAST_GRP_ID, /* u32, dynamically-assigned group id */
	+ __CTRL_ATTR_MCAST_GRP_MAX,
	+};
	+#define CTRL_ATTR_MCAST_GRP_MAX (CTRL_ATTR_MCAST_GRP_MAX - 1)
	+
	+
	+#endif
	+
	diff --git a/sys/netlink/netlink_generic.c b/sys/netlink/netlink_generic.c
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/netlink_generic.c
	@@ -0,0 +1,472 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+#include <sys/cdefs.h>
	+__FBSDID("$FreeBSD$");
	+#include <sys/types.h>
	+#include <sys/malloc.h>
	+#include <sys/priv.h>
	+#include <sys/socket.h>
	+#include <sys/ck.h>
	+
	+#include <netlink/netlink.h>
	+#include <netlink/netlink_ctl.h>
	+#include <netlink/netlink_var.h>
	+#include <netlink/netlink_generic.h>
	+
	+#define DEBUG_MOD_NAME nl_generic
	+#define DEBUG_MAX_LEVEL LOG_DEBUG3
	+#include <netlink/netlink_debug.h>
	+_DECLARE_DEBUG(LOG_DEBUG3);
	+
	+#define MAX_FAMILIES 20
	+#define MAX_GROUPS 20
	+
	+#define MIN_GROUP_NUM 48
	+
	+static struct sx sx_lock;
	+
	+#define GENL_LOCK_INIT() sx_init(&sx_lock, "genetlink lock")
	+#define GENL_LOCK_DESTROY() sx_destroy(&sx_lock)
	+#define GENL_LOCK() sx_xlock(&sx_lock)
	+#define GENL_UNLOCK() sx_xunlock(&sx_lock)
	+
	+struct genl_family {
	+ const char *family_name;
	+ uint16_t family_hdrsize;
	+ uint16_t family_id;
	+ uint16_t family_version;
	+ uint16_t family_attr_max;
	+ uint16_t family_cmd_size;
	+ uint16_t family_num_groups;
	+ struct genl_cmd *family_cmds;
	+};
	+
	+static struct genl_family families[MAX_FAMILIES];
	+
	+
	+struct genl_group {
	+ struct genl_family *group_family;
	+ const char *group_name;
	+};
	+static struct genl_group groups[MAX_GROUPS];
	+
	+
	+static int dump_family(struct nlmsghdr hdr, struct genlmsghdr ghdr,
	+ const struct genl_family gf, struct nl_writer nw);
	+static void nlctrl_notify(const struct genl_family *gf, int action);
	+
	+static struct genl_family *
	+find_family(const char *family_name)
	+{
	+ for (int i = 0; i < MAX_FAMILIES; i++) {
	+ struct genl_family *gf = &families[i];
	+ if (gf->family_name != NULL && !strcmp(gf->family_name, family_name))
	+ return (gf);
	+ }
	+
	+ return (NULL);
	+}
	+
	+uint32_t
	+genl_register_family(const char *family_name, size_t hdrsize, int family_version,
	+ int max_attr_idx)
	+{
	+ uint32_t family_id = 0;
	+
	+ MPASS(family_name != NULL);
	+ if (find_family(family_name) != NULL)
	+ return (0);
	+
	+ GENL_LOCK();
	+ for (int i = 0; i < MAX_FAMILIES; i++) {
	+ struct genl_family *gf = &families[i];
	+ if (gf->family_name == NULL) {
	+ gf->family_name = family_name;
	+ gf->family_version = family_version;
	+ gf->family_hdrsize = hdrsize;
	+ gf->family_attr_max = max_attr_idx;
	+ gf->family_id = i + GENL_MIN_ID;
	+ NL_LOG(LOG_DEBUG2, "Registered family %s id %d",
	+ gf->family_name, gf->family_id);
	+ family_id = gf->family_id;
	+ nlctrl_notify(gf, CTRL_CMD_NEWFAMILY);
	+ break;
	+ }
	+ }
	+ GENL_UNLOCK();
	+
	+ return (family_id);
	+}
	+
	+static void
	+free_family(struct genl_family *gf)
	+{
	+ if (gf->family_cmds != NULL)
	+ free(gf->family_cmds, M_NETLINK);
	+}
	+
	+/*
	+ * Can sleep, I guess
	+ */
	+bool
	+genl_unregister_family(const char *family_name)
	+{
	+ bool found = false;
	+
	+ GENL_LOCK();
	+ struct genl_family *gf = find_family(family_name);
	+
	+ nlctrl_notify(gf, CTRL_CMD_DELFAMILY);
	+
	+ if (gf != NULL) {
	+ found = true;
	+ /* TODO: zero pointer first */
	+ free_family(gf);
	+ bzero(gf, sizeof(*gf));
	+ }
	+ GENL_UNLOCK();
	+
	+ return (found);
	+}
	+
	+bool
	+genl_register_cmds(const char family_name, const struct genl_cmd cmds, int count)
	+{
	+ GENL_LOCK();
	+ struct genl_family *gf = find_family(family_name);
	+ if (gf == NULL) {
	+ GENL_UNLOCK();
	+ return (false);
	+ }
	+
	+ int cmd_size = gf->family_cmd_size;
	+
	+ for (int i = 0; i < count; i++) {
	+ MPASS(cmds[i].cmd_cb != NULL);
	+ if (cmds[i].cmd_num >= cmd_size)
	+ cmd_size = cmds[i].cmd_num + 1;
	+ }
	+
	+ if (cmd_size > gf->family_cmd_size) {
	+ /* need to realloc */
	+ size_t sz = cmd_size * sizeof(struct genl_cmd);
	+ void *data = malloc(sz, M_NETLINK, M_WAITOK \| M_ZERO);
	+
	+ memcpy(data, gf->family_cmds, gf->family_cmd_size * sizeof(struct genl_cmd));
	+ void *old_data = gf->family_cmds;
	+ gf->family_cmds = data;
	+ gf->family_cmd_size = cmd_size;
	+ free(old_data, M_NETLINK);
	+ }
	+
	+ for (int i = 0; i < count; i++) {
	+ const struct genl_cmd *cmd = &cmds[i];
	+ MPASS(gf->family_cmds[cmd->cmd_num].cmd_cb == NULL);
	+ gf->family_cmds[cmd->cmd_num] = cmds[i];
	+ NL_LOG(LOG_DEBUG2, "Adding cmd %s(%d) to family %s",
	+ cmd->cmd_name, cmd->cmd_num, gf->family_name);
	+ }
	+ GENL_UNLOCK();
	+ return (true);
	+}
	+
	+static struct genl_group *
	+find_group(const struct genl_family gf, const char group_name)
	+{
	+ for (int i = 0; i < MAX_GROUPS; i++) {
	+ struct genl_group *gg = &groups[i];
	+ if (gg->group_family == gf && !strcmp(gg->group_name, group_name))
	+ return (gg);
	+ }
	+ return (NULL);
	+}
	+
	+uint32_t
	+genl_register_group(const char family_name, const char group_name)
	+{
	+ uint32_t group_id = 0;
	+
	+ MPASS(family_name != NULL);
	+ MPASS(group_name != NULL);
	+
	+ GENL_LOCK();
	+ struct genl_family *gf = find_family(family_name);
	+
	+ if (gf == NULL \|\| find_group(gf, group_name) != NULL) {
	+ GENL_UNLOCK();
	+ return (0);
	+ }
	+
	+ for (int i = 0; i < MAX_GROUPS; i++) {
	+ struct genl_group *gg = &groups[i];
	+ if (gg->group_family == NULL) {
	+ gf->family_num_groups++;
	+ gg->group_family = gf;
	+ gg->group_name = group_name;
	+ group_id = i + MIN_GROUP_NUM;
	+ break;
	+ }
	+ }
	+ GENL_UNLOCK();
	+
	+ return (group_id);
	+}
	+
	+/*
	+ * Handler called by netlink subsystem when matching netlink message is received
	+ */
	+static int
	+genl_handle_message(struct nlmsghdr hdr, struct nl_pstate npt)
	+{
	+ struct nlpcb *nlp = npt->nlp;
	+ int error = 0;
	+
	+ int family_id = (int)hdr->nlmsg_type - GENL_MIN_ID;
	+
	+ if (__predict_false(family_id < 0 \|\| family_id > MAX_FAMILIES)) {
	+ NLP_LOG(LOG_DEBUG, nlp, "invalid message type: %d", hdr->nlmsg_type);
	+ return (ENOTSUP);
	+ }
	+
	+ if (__predict_false(hdr->nlmsg_len < sizeof(hdr) + GENL_HDRLEN)) {
	+ NLP_LOG(LOG_DEBUG, nlp, "invalid message size: %d", hdr->nlmsg_len);
	+ return (EINVAL);
	+ }
	+
	+ struct genl_family *gf = &families[family_id];
	+
	+ struct genlmsghdr ghdr = (struct genlmsghdr )(hdr + 1);
	+
	+ if (ghdr->cmd >= gf->family_cmd_size \|\| gf->family_cmds[ghdr->cmd].cmd_cb == NULL) {
	+ NLP_LOG(LOG_DEBUG, nlp, "family %s: invalid cmd %d",
	+ gf->family_name, ghdr->cmd);
	+ return (ENOTSUP);
	+ }
	+
	+ struct genl_cmd *cmd = &gf->family_cmds[ghdr->cmd];
	+
	+ if (cmd->cmd_priv != 0 && !nlp_has_priv(nlp, cmd->cmd_priv)) {
	+ NLP_LOG(LOG_DEBUG, nlp, "family %s: cmd %d priv_check() failed",
	+ gf->family_name, ghdr->cmd);
	+ return (EPERM);
	+ }
	+
	+ NLP_LOG(LOG_DEBUG2, nlp, "received family %s cmd %s(%d) len %d",
	+ gf->family_name, cmd->cmd_name, ghdr->cmd, hdr->nlmsg_len);
	+
	+ error = cmd->cmd_cb(hdr, npt);
	+
	+ return (error);
	+}
	+
	+static uint32_t
	+get_cmd_flags(const struct genl_cmd *cmd)
	+{
	+ uint32_t flags = cmd->cmd_flags;
	+ if (cmd->cmd_priv != 0)
	+ flags \|= GENL_ADMIN_PERM;
	+ return (flags);
	+}
	+
	+static int
	+dump_family(struct nlmsghdr hdr, struct genlmsghdr ghdr,
	+ const struct genl_family gf, struct nl_writer nw)
	+{
	+ if (!nlmsg_reply(nw, hdr, sizeof(struct genlmsghdr)))
	+ goto enomem;
	+
	+ struct genlmsghdr *ghdr_new = nlmsg_reserve_object(nw, struct genlmsghdr);
	+ ghdr_new->cmd = ghdr->cmd;
	+ ghdr_new->version = gf->family_version;
	+ ghdr_new->reserved = 0;
	+
	+ nlattr_add_string(nw, CTRL_ATTR_FAMILY_NAME, gf->family_name);
	+ nlattr_add_u16(nw, CTRL_ATTR_FAMILY_ID, gf->family_id);
	+ nlattr_add_u32(nw, CTRL_ATTR_VERSION, gf->family_version);
	+ nlattr_add_u32(nw, CTRL_ATTR_HDRSIZE, gf->family_hdrsize);
	+ nlattr_add_u32(nw, CTRL_ATTR_MAXATTR, gf->family_attr_max);
	+
	+ if (gf->family_cmd_size > 0) {
	+ int off = nlattr_add_nested(nw, CTRL_ATTR_OPS);
	+ if (off == 0)
	+ goto enomem;
	+ for (int i = 0, cnt=0; i < gf->family_cmd_size; i++) {
	+ struct genl_cmd *cmd = &gf->family_cmds[i];
	+ if (cmd->cmd_cb == NULL)
	+ continue;
	+ int cmd_off = nlattr_add_nested(nw, ++cnt);
	+ if (cmd_off == 0)
	+ goto enomem;
	+
	+ nlattr_add_u32(nw, CTRL_ATTR_OP_ID, cmd->cmd_num);
	+ nlattr_add_u32(nw, CTRL_ATTR_OP_FLAGS, get_cmd_flags(cmd));
	+ nlattr_set_len(nw, cmd_off);
	+ }
	+ nlattr_set_len(nw, off);
	+ }
	+ if (gf->family_num_groups > 0) {
	+ int off = nlattr_add_nested(nw, CTRL_ATTR_MCAST_GROUPS);
	+ if (off == 0)
	+ goto enomem;
	+ for (int i = 0, cnt = 0; i < MAX_GROUPS; i++) {
	+ struct genl_group *gg = &groups[i];
	+ if (gg->group_family != gf)
	+ continue;
	+
	+ int cmd_off = nlattr_add_nested(nw, ++cnt);
	+ if (cmd_off == 0)
	+ goto enomem;
	+ nlattr_add_u32(nw, CTRL_ATTR_MCAST_GRP_ID, i + MIN_GROUP_NUM);
	+ nlattr_add_string(nw, CTRL_ATTR_MCAST_GRP_NAME, gg->group_name);
	+ nlattr_set_len(nw, cmd_off);
	+ }
	+ nlattr_set_len(nw, off);
	+ }
	+ if (nlmsg_end(nw))
	+ return (0);
	+enomem:
	+ NL_LOG(LOG_DEBUG, "unable to dump family %s state (ENOMEM)", gf->family_name);
	+ nlmsg_abort(nw);
	+ return (ENOMEM);
	+}
	+
	+
	+/* Declare ourself as a user */
	+#define CTRL_FAMILY_NAME "nlctrl"
	+
	+static uint32_t ctrl_family_id;
	+static uint32_t ctrl_group_id;
	+
	+struct nl_parsed_family {
	+ uint32_t family_id;
	+ char *family_name;
	+ uint8_t version;
	+};
	+
	+#define _IN(_field) offsetof(struct genlmsghdr, _field)
	+#define _OUT(_field) offsetof(struct nl_parsed_family, _field)
	+static const struct nlfield_parser nlf_p_generic[] = {
	+ { .off_in = _IN(version), .off_out = _OUT(version), .cb = nlf_get_u8 },
	+};
	+
	+static struct nlattr_parser nla_p_generic[] = {
	+ { .type = CTRL_ATTR_FAMILY_ID , .off = _OUT(family_id), .cb = nlattr_get_uint32 },
	+ { .type = CTRL_ATTR_FAMILY_NAME , .off = _OUT(family_id), .cb = nlattr_get_string },
	+};
	+#undef _IN
	+#undef _OUT
	+NL_DECLARE_PARSER(genl_parser, struct genlmsghdr, nlf_p_generic, nla_p_generic);
	+
	+static int
	+nlctrl_handle_getfamily(struct nlmsghdr hdr, struct nl_pstate npt)
	+{
	+ int error = 0;
	+
	+ struct nl_parsed_family attrs = {};
	+ error = nl_parse_nlmsg(hdr, &genl_parser, npt, &attrs);
	+ if (error != 0)
	+ return (error);
	+
	+ struct genlmsghdr ghdr = {
	+ .cmd = CTRL_CMD_NEWFAMILY,
	+ };
	+
	+ for (int i = 0; i < MAX_FAMILIES; i++) {
	+ struct genl_family *gf = &families[i];
	+ if (gf->family_name == NULL)
	+ continue;
	+ if (attrs.family_id != 0 && attrs.family_id != gf->family_id)
	+ continue;
	+ if (attrs.family_name != NULL && strcmp(attrs.family_name, gf->family_name))
	+ continue;
	+ error = dump_family(hdr, &ghdr, &families[i], npt->nw);
	+ if (error != 0)
	+ break;
	+ }
	+
	+ return (error);
	+}
	+
	+static void
	+nlctrl_notify(const struct genl_family *gf, int cmd)
	+{
	+ struct nlmsghdr hdr = {.nlmsg_type = NETLINK_GENERIC };
	+ struct genlmsghdr ghdr = { .cmd = cmd };
	+ struct nl_writer nw = {};
	+
	+ if (nlmsg_get_group_writer(&nw, NLMSG_SMALL, NETLINK_GENERIC, ctrl_group_id)) {
	+ dump_family(&hdr, &ghdr, gf, &nw);
	+ nlmsg_flush(&nw);
	+ return;
	+ }
	+ NL_LOG(LOG_DEBUG, "error allocating group writer");
	+}
	+
	+static const struct genl_cmd nlctrl_cmds[] = {
	+ {
	+ .cmd_num = CTRL_CMD_GETFAMILY,
	+ .cmd_name = "GETFAMILY",
	+ .cmd_cb = nlctrl_handle_getfamily,
	+ .cmd_flags = GENL_CMD_CAP_DO \| GENL_CMD_CAP_DUMP, GENL_CMD_CAP_HASPOL,
	+ },
	+};
	+
	+static void
	+genl_nlctrl_init()
	+{
	+ ctrl_family_id = genl_register_family(CTRL_FAMILY_NAME, 0, 2, CTRL_ATTR_MAX);
	+ genl_register_cmds(CTRL_FAMILY_NAME, nlctrl_cmds, NL_ARRAY_LEN(nlctrl_cmds));
	+ ctrl_group_id = genl_register_group(CTRL_FAMILY_NAME, "notify");
	+}
	+
	+static void
	+genl_nlctrl_destroy()
	+{
	+ genl_unregister_family(CTRL_FAMILY_NAME);
	+}
	+
	+static const struct nlhdr_parser *all_parsers[] = { &genl_parser };
	+
	+static void
	+genl_load(void *u __unused)
	+{
	+ GENL_LOCK_INIT();
	+ NL_VERIFY_PARSERS(all_parsers);
	+ netlink_register_proto(NETLINK_GENERIC, "NETLINK_GENERIC", genl_handle_message);
	+ genl_nlctrl_init();
	+}
	+SYSINIT(genl_load, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, genl_load, NULL);
	+
	+static void
	+genl_unload(void *u __unused)
	+{
	+ genl_nlctrl_destroy();
	+ GENL_LOCK_DESTROY();
	+ epoch_wait_preempt(net_epoch_preempt);
	+}
	+SYSUNINIT(genl_unload, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, genl_unload, NULL);
	diff --git a/sys/netlink/netlink_io.c b/sys/netlink/netlink_io.c
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/netlink_io.c
	@@ -0,0 +1,528 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2021 Ng Peng Nam Sean
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+#include <sys/cdefs.h>
	+__FBSDID("$FreeBSD$");
	+#include <sys/param.h>
	+#include <sys/malloc.h>
	+#include <sys/lock.h>
	+#include <sys/mbuf.h>
	+#include <sys/ck.h>
	+#include <sys/socket.h>
	+#include <sys/socketvar.h>
	+#include <sys/syslog.h>
	+
	+#include <netlink/netlink.h>
	+#include <netlink/netlink_ctl.h>
	+#include <netlink/netlink_linux.h>
	+#include <netlink/netlink_var.h>
	+
	+#define DEBUG_MOD_NAME nl_io
	+#define DEBUG_MAX_LEVEL LOG_DEBUG3
	+#include <netlink/netlink_debug.h>
	+_DECLARE_DEBUG(LOG_DEBUG);
	+
	+/*
	+ * The logic below provide a p2p interface for receiving and
	+ * sending netlink data between the kernel and userland.
	+ */
	+
	+static const struct sockaddr_nl _nl_empty_src = {
	+ .nl_len = sizeof(struct sockaddr_nl),
	+ .nl_family = PF_NETLINK,
	+ .nl_pid = 0 /* comes from the kernel */
	+};
	+static const struct sockaddr nl_empty_src = (const struct sockaddr )&_nl_empty_src;
	+
	+static struct mbuf nl_process_mbuf(struct mbuf m, struct nlpcb *nlp);
	+
	+
	+static void
	+queue_push(struct nl_io_queue q, struct mbuf mq)
	+{
	+ while (mq != NULL) {
	+ struct mbuf *m = mq;
	+ mq = mq->m_nextpkt;
	+ m->m_nextpkt = NULL;
	+
	+ q->length += m_length(m, NULL);
	+ STAILQ_INSERT_TAIL(&q->head, m, m_stailqpkt);
	+ }
	+}
	+
	+static void
	+queue_push_head(struct nl_io_queue q, struct mbuf m)
	+{
	+ MPASS(m->m_nextpkt == NULL);
	+
	+ q->length += m_length(m, NULL);
	+ STAILQ_INSERT_HEAD(&q->head, m, m_stailqpkt);
	+}
	+
	+static struct mbuf *
	+queue_pop(struct nl_io_queue *q)
	+{
	+ if (!STAILQ_EMPTY(&q->head)) {
	+ struct mbuf *m = STAILQ_FIRST(&q->head);
	+ STAILQ_REMOVE_HEAD(&q->head, m_stailqpkt);
	+ m->m_nextpkt = NULL;
	+ q->length -= m_length(m, NULL);
	+
	+ return (m);
	+ }
	+ return (NULL);
	+}
	+
	+static struct mbuf *
	+queue_head(const struct nl_io_queue *q)
	+{
	+ return (STAILQ_FIRST(&q->head));
	+}
	+
	+static inline bool
	+queue_empty(const struct nl_io_queue *q)
	+{
	+ return (q->length == 0);
	+}
	+
	+static void
	+queue_free(struct nl_io_queue *q)
	+{
	+ while (!STAILQ_EMPTY(&q->head)) {
	+ struct mbuf *m = STAILQ_FIRST(&q->head);
	+ STAILQ_REMOVE_HEAD(&q->head, m_stailqpkt);
	+ m->m_nextpkt = NULL;
	+ m_freem(m);
	+ }
	+ q->length = 0;
	+}
	+
	+
	+static void
	+nl_schedule_taskqueue(struct nlpcb *nlp)
	+{
	+ if (!nlp->nl_task_pending) {
	+ nlp->nl_task_pending = true;
	+ taskqueue_enqueue(nlp->nl_taskqueue, &nlp->nl_task);
	+ NL_LOG(LOG_DEBUG3, "taskqueue scheduled");
	+ } else {
	+ NL_LOG(LOG_DEBUG3, "taskqueue schedule skipped");
	+ }
	+}
	+
	+int
	+nl_receive_async(struct mbuf m, struct socket so)
	+{
	+ struct nlpcb *nlp = sotonlpcb(so);
	+ int error = 0;
	+
	+ m->m_nextpkt = NULL;
	+
	+ NLP_LOCK(nlp);
	+
	+ if ((__predict_true(nlp->nl_active))) {
	+ sbappend(&so->so_snd, m, 0);
	+ NL_LOG(LOG_DEBUG3, "enqueue %u bytes", m_length(m, NULL));
	+ nl_schedule_taskqueue(nlp);
	+ } else {
	+ NL_LOG(LOG_DEBUG, "ignoring %u bytes on non-active socket",
	+ m_length(m, NULL));
	+ m_free(m);
	+ error = EINVAL;
	+ }
	+
	+ NLP_UNLOCK(nlp);
	+
	+ return (error);
	+}
	+
	+static bool
	+tx_check_locked(struct nlpcb *nlp)
	+{
	+ if (queue_empty(&nlp->tx_queue))
	+ return (true);
	+
	+ /*
	+ * Check if something can be moved from the internal TX queue
	+ * to the socket queue.
	+ */
	+
	+ bool appended = false;
	+ struct sockbuf *sb = &nlp->nl_socket->so_rcv;
	+ SOCKBUF_LOCK(sb);
	+
	+ while (true) {
	+ struct mbuf *m = queue_head(&nlp->tx_queue);
	+ if (m && sbappendaddr_locked(sb, nl_empty_src, m, NULL) != 0) {
	+ /* appended successfully */
	+ queue_pop(&nlp->tx_queue);
	+ appended = true;
	+ } else
	+ break;
	+ }
	+
	+ SOCKBUF_UNLOCK(sb);
	+
	+ if (appended)
	+ sorwakeup(nlp->nl_socket);
	+
	+ return (queue_empty(&nlp->tx_queue));
	+}
	+
	+static bool
	+nl_process_received_one(struct nlpcb *nlp)
	+{
	+ bool reschedule = false;
	+
	+ NLP_LOCK(nlp);
	+ nlp->nl_task_pending = false;
	+
	+ if (!tx_check_locked(nlp)) {
	+ /* TX overflow queue still not empty, ignore RX */
	+ NLP_UNLOCK(nlp);
	+ return (false);
	+ }
	+
	+ if (queue_empty(&nlp->rx_queue)) {
	+ /*
	+ * Grab all data we have from the socket TX queue
	+ * and store it the internal queue, so it can be worked on
	+ * w/o holding socket lock.
	+ */
	+ struct sockbuf *sb = &nlp->nl_socket->so_snd;
	+
	+ SOCKBUF_LOCK(sb);
	+ unsigned int avail = sbavail(sb);
	+ if (avail > 0) {
	+ NL_LOG(LOG_DEBUG3, "grabbed %u bytes", avail);
	+ queue_push(&nlp->rx_queue, sbcut_locked(sb, avail));
	+ }
	+ SOCKBUF_UNLOCK(sb);
	+ } else {
	+ /* Schedule another pass to read from the socket queue */
	+ reschedule = true;
	+ }
	+
	+ int prev_hiwat = nlp->tx_queue.hiwat;
	+ NLP_UNLOCK(nlp);
	+
	+ while (!queue_empty(&nlp->rx_queue)) {
	+ struct mbuf *m = queue_pop(&nlp->rx_queue);
	+
	+ m = nl_process_mbuf(m, nlp);
	+ if (m != NULL) {
	+ queue_push_head(&nlp->rx_queue, m);
	+ reschedule = false;
	+ break;
	+ }
	+ }
	+ if (nlp->tx_queue.hiwat > prev_hiwat) {
	+ NLP_LOG(LOG_DEBUG, nlp, "TX override peaked to %d", nlp->tx_queue.hiwat);
	+
	+ }
	+
	+ return (reschedule);
	+}
	+
	+static void
	+nl_process_received(struct nlpcb *nlp)
	+{
	+ NL_LOG(LOG_DEBUG3, "taskqueue called");
	+
	+ while (nl_process_received_one(nlp))
	+ ;
	+}
	+
	+void
	+nl_init_io(struct nlpcb *nlp)
	+{
	+ STAILQ_INIT(&nlp->rx_queue.head);
	+ STAILQ_INIT(&nlp->tx_queue.head);
	+}
	+
	+void
	+nl_free_io(struct nlpcb *nlp)
	+{
	+ queue_free(&nlp->rx_queue);
	+ queue_free(&nlp->tx_queue);
	+}
	+
	+/*
	+ * Called after some data have been read from the socket.
	+ */
	+void
	+nl_on_transmit(struct nlpcb *nlp)
	+{
	+ NLP_LOCK(nlp);
	+
	+ struct socket *so = nlp->nl_socket;
	+ if (__predict_false(nlp->nl_dropped_bytes > 0 && so != NULL)) {
	+ uint64_t dropped_bytes = nlp->nl_dropped_bytes;
	+ uint64_t dropped_messages = nlp->nl_dropped_messages;
	+ nlp->nl_dropped_bytes = 0;
	+ nlp->nl_dropped_messages = 0;
	+
	+ struct sockbuf *sb = &so->so_rcv;
	+ NLP_LOG(LOG_DEBUG, nlp,
	+ "socket RX overflowed, %lu messages (%lu bytes) dropped. "
	+ "bytes: [%u/%u] mbufs: [%u/%u]", dropped_messages, dropped_bytes,
	+ sb->sb_ccc, sb->sb_hiwat, sb->sb_mbcnt, sb->sb_mbmax);
	+ /* TODO: send netlink message */
	+ }
	+
	+ nl_schedule_taskqueue(nlp);
	+ NLP_UNLOCK(nlp);
	+}
	+
	+void
	+nl_taskqueue_handler(void *_arg, int pending)
	+{
	+ struct nlpcb nlp = (struct nlpcb )_arg;
	+
	+ CURVNET_SET(nlp->nl_socket->so_vnet);
	+ nl_process_received(nlp);
	+ CURVNET_RESTORE();
	+}
	+
	+static __noinline void
	+queue_push_tx(struct nlpcb nlp, struct mbuf m)
	+{
	+ queue_push(&nlp->tx_queue, m);
	+ nlp->nl_tx_blocked = true;
	+
	+ if (nlp->tx_queue.length > nlp->tx_queue.hiwat)
	+ nlp->tx_queue.hiwat = nlp->tx_queue.length;
	+}
	+
	+/*
	+ * Tries to send @m to the socket @nlp.
	+ *
	+ * @m: mbuf(s) to send to. Consumed in any case.
	+ * @nlp: socket to send to
	+ * @cnt: number of messages in @m
	+ * @io_flags: combination of NL_IOF_* flags
	+ *
	+ * Returns true on success.
	+ * If no queue overrunes happened, wakes up socket owner.
	+ */
	+bool
	+nl_send_one(struct mbuf m, struct nlpcb nlp, int num_messages, int io_flags)
	+{
	+ bool untranslated = io_flags & NL_IOF_UNTRANSLATED;
	+ bool ignore_limits = io_flags & NL_IOF_IGNORE_LIMIT;
	+ bool result = true;
	+
	+ IF_DEBUG_LEVEL(LOG_DEBUG2) {
	+ struct nlmsghdr hdr = mtod(m, struct nlmsghdr );
	+ NLP_LOG(LOG_DEBUG2, nlp,
	+ "TX mbuf len %u msgs %u msg type %d first hdrlen %u io_flags %X",
	+ m_length(m, NULL), num_messages, hdr->nlmsg_type, hdr->nlmsg_len,
	+ io_flags);
	+ }
	+
	+ if (__predict_false(nlp->nl_linux && linux_netlink_p != NULL && untranslated)) {
	+ m = linux_netlink_p->mbufs_to_linux(nlp->nl_proto, m, nlp);
	+ if (m == NULL)
	+ return (false);
	+ }
	+
	+ NLP_LOCK(nlp);
	+
	+ if (__predict_false(nlp->nl_socket == NULL)) {
	+ NLP_UNLOCK(nlp);
	+ m_freem(m);
	+ return (false);
	+ }
	+
	+ if (!queue_empty(&nlp->tx_queue)) {
	+ if (ignore_limits) {
	+ queue_push_tx(nlp, m);
	+ } else {
	+ m_free(m);
	+ result = false;
	+ }
	+ NLP_UNLOCK(nlp);
	+ return (result);
	+ }
	+
	+ struct socket *so = nlp->nl_socket;
	+ if (sbappendaddr(&so->so_rcv, nl_empty_src, m, NULL) != 0) {
	+ sorwakeup(so);
	+ NLP_LOG(LOG_DEBUG3, nlp, "appended data & woken up");
	+ } else {
	+ if (ignore_limits) {
	+ queue_push_tx(nlp, m);
	+ } else {
	+ /*
	+ * Store dropped data so it can be reported
	+ * on the next read
	+ */
	+ nlp->nl_dropped_bytes += m_length(m, NULL);
	+ nlp->nl_dropped_messages += num_messages;
	+ NLP_LOG(LOG_DEBUG2, nlp, "RX oveflow: %lu m (+%d), %lu b (+%d)",
	+ nlp->nl_dropped_messages, num_messages,
	+ nlp->nl_dropped_bytes, m_length(m, NULL));
	+ soroverflow(so);
	+ m_freem(m);
	+ result = false;
	+ }
	+ }
	+ NLP_UNLOCK(nlp);
	+
	+ return (result);
	+}
	+
	+static int
	+nl_receive_message(struct nlmsghdr *hdr, int remaining_length,
	+ struct nlpcb nlp, struct nl_pstate npt)
	+{
	+ nl_handler_f handler = nl_handlers[nlp->nl_proto].cb;
	+ int error = 0;
	+
	+ NL_LOG(LOG_DEBUG2, "msg len: %d type: %d", hdr->nlmsg_len,
	+ hdr->nlmsg_type);
	+
	+ if (__predict_false(hdr->nlmsg_len > remaining_length)) {
	+ NLP_LOG(LOG_DEBUG, nlp, "message is not entirely present: want %d got %d",
	+ hdr->nlmsg_len, remaining_length);
	+ return (EINVAL);
	+ } else if (__predict_false(hdr->nlmsg_len < sizeof(*hdr))) {
	+ NL_LOG(LOG_DEBUG, "message too short: %d", hdr->nlmsg_len);
	+ return (EINVAL);
	+ }
	+ /* Stamp each message with sender pid */
	+ hdr->nlmsg_pid = nlp->nl_port;
	+
	+ npt->hdr = hdr;
	+
	+ if (hdr->nlmsg_flags & NLM_F_REQUEST && hdr->nlmsg_type >= NLMSG_MIN_TYPE) {
	+ NL_LOG(LOG_DEBUG2, "handling message with msg type: %d",
	+ hdr->nlmsg_type);
	+
	+ if (nlp->nl_linux && linux_netlink_p != NULL) {
	+ struct nlmsghdr *hdr_orig = hdr;
	+ hdr = linux_netlink_p->msg_from_linux(nlp->nl_proto, hdr, npt);
	+ if (hdr == NULL) {
	+ npt->hdr = hdr_orig;
	+ if (hdr->nlmsg_flags & NLM_F_ACK)
	+ nlmsg_ack(nlp, EAGAIN, hdr, npt);
	+ return (0);
	+ }
	+ }
	+ error = handler(hdr, npt);
	+ NL_LOG(LOG_DEBUG2, "retcode: %d", error);
	+ }
	+ if ((hdr->nlmsg_flags & NLM_F_ACK) \|\| (error != 0 && error != EINTR)) {
	+ NL_LOG(LOG_DEBUG3, "ack");
	+ nlmsg_ack(nlp, error, hdr, npt);
	+ NL_LOG(LOG_DEBUG3, "done");
	+ }
	+
	+ return (0);
	+}
	+
	+static void
	+npt_clear(struct nl_pstate *npt)
	+{
	+ lb_clear(&npt->lb);
	+ npt->error = 0;
	+ npt->err_msg = NULL;
	+ npt->err_off = 0;
	+ npt->hdr = NULL;
	+}
	+
	+/*
	+ * Processes an incoming packet, which can contain multiple netlink messages
	+ */
	+static struct mbuf *
	+nl_process_mbuf(struct mbuf m, struct nlpcb nlp)
	+{
	+ int offset, buffer_length;
	+ struct nlmsghdr *hdr;
	+ char *buffer;
	+ int error;
	+
	+ NL_LOG(LOG_DEBUG3, "RX netlink mbuf %p on %p", m, nlp->nl_socket);
	+
	+ struct nl_writer nw = {};
	+ if (!nlmsg_get_unicast_writer(&nw, NLMSG_SMALL, nlp)) {
	+ m_freem(m);
	+ NL_LOG(LOG_DEBUG, "error allocating socket writer");
	+ return (NULL);
	+ }
	+
	+ nlmsg_ignore_limit(&nw);
	+ /* TODO: alloc this buf once for nlp */
	+ int data_length = m_length(m, NULL);
	+ buffer_length = roundup2(data_length, 8) + SCRATCH_BUFFER_SIZE;
	+ if (nlp->nl_linux)
	+ buffer_length += roundup2(data_length, 8);
	+ buffer = malloc(buffer_length, M_NETLINK, M_NOWAIT \| M_ZERO);
	+ if (buffer == NULL) {
	+ m_freem(m);
	+ nlmsg_flush(&nw);
	+ NL_LOG(LOG_DEBUG, "Unable to allocate %d bytes of memory",
	+ buffer_length);
	+ return (NULL);
	+ }
	+ m_copydata(m, 0, data_length, buffer);
	+
	+ struct nl_pstate npt = {
	+ .nlp = nlp,
	+ .lb.base = &buffer[roundup2(data_length, 8)],
	+ .lb.size = buffer_length - roundup2(data_length, 8),
	+ .nw = &nw,
	+ .strict = nlp->nl_flags & NLF_STRICT,
	+ };
	+
	+ for (offset = 0; offset + sizeof(struct nlmsghdr) <= data_length;) {
	+ hdr = (struct nlmsghdr *)&buffer[offset];
	+ /* Save length prior to calling handler */
	+ int msglen = NLMSG_ALIGN(hdr->nlmsg_len);
	+ NL_LOG(LOG_DEBUG3, "parsing offset %d/%d", offset, data_length);
	+ npt_clear(&npt);
	+ error = nl_receive_message(hdr, data_length - offset, nlp, &npt);
	+ offset += msglen;
	+ if (__predict_false(error != 0 \|\| nlp->nl_tx_blocked))
	+ break;
	+ }
	+ NL_LOG(LOG_DEBUG3, "packet parsing done");
	+ free(buffer, M_NETLINK);
	+ nlmsg_flush(&nw);
	+
	+ if (nlp->nl_tx_blocked) {
	+ NLP_LOCK(nlp);
	+ nlp->nl_tx_blocked = false;
	+ NLP_UNLOCK(nlp);
	+ m_adj(m, offset);
	+ return (m);
	+ } else {
	+ m_freem(m);
	+ return (NULL);
	+ }
	+}
	diff --git a/sys/netlink/netlink_linux.h b/sys/netlink/netlink_linux.h
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/netlink_linux.h
	@@ -0,0 +1,54 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+#ifndef _NETLINK_LINUX_VAR_H_
	+#define _NETLINK_LINUX_VAR_H_
	+
	+/*
	+ * The file contains headers for the bridge interface between
	+ * linux[_common] module and the netlink module
	+ */
	+struct nlpcb;
	+struct nl_pstate;
	+
	+typedef struct mbuf mbufs_to_linux_cb_t(int netlink_family, struct mbuf m,
	+ struct nlpcb *nlp);
	+typedef struct mbuf msgs_to_linux_cb_t(int netlink_family, char buf, int data_length,
	+ struct nlpcb *nlp);
	+typedef struct nlmsghdr msg_from_linux_cb_t(int netlink_family, struct nlmsghdr hdr,
	+ struct nl_pstate *npt);
	+
	+struct linux_netlink_provider {
	+ mbufs_to_linux_cb_t *mbufs_to_linux;
	+ msgs_to_linux_cb_t *msgs_to_linux;
	+ msg_from_linux_cb_t *msg_from_linux;
	+
	+};
	+
	+extern struct linux_netlink_provider *linux_netlink_p;
	+
	+#endif
	diff --git a/sys/netlink/netlink_message_parser.h b/sys/netlink/netlink_message_parser.h
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/netlink_message_parser.h
	@@ -0,0 +1,270 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+#ifndef _NETLINK_NETLINK_MESSAGE_PARSER_H_
	+#define _NETLINK_NETLINK_MESSAGE_PARSER_H_
	+
	+/*
	+ * It is not meant to be included directly
	+ */
	+
	+/* Parsing state */
	+struct linear_buffer {
	+ char base; / Base allocated memory pointer */
	+ uint32_t offset; /* Currently used offset */
	+ uint32_t size; /* Total buffer size */
	+};
	+
	+static inline void *
	+lb_alloc(struct linear_buffer *lb, int len)
	+{
	+ len = roundup2(len, sizeof(uint64_t));
	+ if (lb->offset + len > lb->size)
	+ return (NULL);
	+ void data = (void )(lb->base + lb->offset);
	+ lb->offset += len;
	+ return (data);
	+}
	+
	+static inline void
	+lb_clear(struct linear_buffer *lb)
	+{
	+ memset(lb->base, 0, lb->size);
	+ lb->offset = 0;
	+}
	+
	+#define NL_MAX_ERROR_BUF 128
	+#define SCRATCH_BUFFER_SIZE (1024 + NL_MAX_ERROR_BUF)
	+struct nl_pstate {
	+ struct linear_buffer lb; /* Per-message scratch buffer */
	+ struct nlpcb nlp; / Originator socket */
	+ struct nl_writer nw; / Message writer to use */
	+ struct nlmsghdr hdr; / Current parsed message header */
	+ uint32_t err_off; /* error offset from hdr start */
	+ int error; /* last operation error */
	+ char err_msg; / Description of last error */
	+ bool strict; /* Strict parsing required */
	+};
	+
	+static inline void *
	+npt_alloc(struct nl_pstate *npt, int len)
	+{
	+ return (lb_alloc(&npt->lb, len));
	+}
	+#define npt_alloc_sockaddr(_npt, _len) ((struct sockaddr *)(npt_alloc(_npt, _len)))
	+
	+typedef int parse_field_f(void hdr, struct nl_pstate npt,
	+ void *target);
	+struct nlfield_parser {
	+ uint16_t off_in;
	+ uint16_t off_out;
	+ parse_field_f *cb;
	+};
	+static const struct nlfield_parser nlf_p_empty[] = {};
	+
	+int nlf_get_ifp(void src, struct nl_pstate npt, void *target);
	+int nlf_get_ifpz(void src, struct nl_pstate npt, void *target);
	+int nlf_get_u8(void src, struct nl_pstate npt, void *target);
	+int nlf_get_u16(void src, struct nl_pstate npt, void *target);
	+int nlf_get_u32(void src, struct nl_pstate npt, void *target);
	+int nlf_get_u8_u32(void src, struct nl_pstate npt, void *target);
	+
	+
	+struct nlattr_parser;
	+typedef int parse_attr_f(struct nlattr attr, struct nl_pstate npt,
	+ const void arg, void target);
	+struct nlattr_parser {
	+ uint16_t type; /* Attribute type */
	+ uint16_t off; /* field offset in the target structure */
	+ parse_attr_f cb; / parser function to call */
	+ const void *arg;
	+};
	+
	+typedef bool strict_parser_f(void hdr, struct nl_pstate npt);
	+
	+struct nlhdr_parser {
	+ int nl_hdr_off; /* aligned netlink header size */
	+ int out_hdr_off; /* target header size */
	+ int fp_size;
	+ int np_size;
	+ const struct nlfield_parser fp; / array of header field parsers */
	+ const struct nlattr_parser np; / array of attribute parsers */
	+ strict_parser_f sp; / Parser function */
	+};
	+
	+#define NL_DECLARE_PARSER(_name, _t, _fp, _np) \
	+static const struct nlhdr_parser _name = { \
	+ .nl_hdr_off = sizeof(_t), \
	+ .fp = &((_fp)[0]), \
	+ .np = &((_np)[0]), \
	+ .fp_size = NL_ARRAY_LEN(_fp), \
	+ .np_size = NL_ARRAY_LEN(_np), \
	+}
	+
	+#define NL_DECLARE_STRICT_PARSER(_name, _t, _sp, _fp, _np)\
	+static const struct nlhdr_parser _name = { \
	+ .nl_hdr_off = sizeof(_t), \
	+ .fp = &((_fp)[0]), \
	+ .np = &((_np)[0]), \
	+ .fp_size = NL_ARRAY_LEN(_fp), \
	+ .np_size = NL_ARRAY_LEN(_np), \
	+ .sp = _sp, \
	+}
	+
	+#define NL_DECLARE_ARR_PARSER(_name, _t, _o, _fp, _np) \
	+static const struct nlhdr_parser _name = { \
	+ .nl_hdr_off = sizeof(_t), \
	+ .out_hdr_off = sizeof(_o), \
	+ .fp = &((_fp)[0]), \
	+ .np = &((_np)[0]), \
	+ .fp_size = NL_ARRAY_LEN(_fp), \
	+ .np_size = NL_ARRAY_LEN(_np), \
	+}
	+
	+#define NL_DECLARE_ATTR_PARSER(_name, _np) \
	+static const struct nlhdr_parser _name = { \
	+ .np = &((_np)[0]), \
	+ .np_size = NL_ARRAY_LEN(_np), \
	+}
	+
	+struct nlarr_hdr {
	+ int num_items;
	+ int max_items;
	+};
	+
	+int nl_parse_attrs_raw(struct nlattr nla_head, int len, const struct nlattr_parser ps,
	+ int pslen, struct nl_pstate npt, void target);
	+int nl_parse_attrs(struct nlmsghdr hdr, int hdrlen, struct nlattr_parser ps,
	+ int pslen, struct nl_pstate npt, void target);
	+
	+int nlattr_get_flag(struct nlattr nla, struct nl_pstate npt,
	+ const void arg, void target);
	+int nlattr_get_ip(struct nlattr nla, struct nl_pstate npt,
	+ const void arg, void target);
	+int nlattr_get_uint16(struct nlattr nla, struct nl_pstate npt,
	+ const void arg, void target);
	+int nlattr_get_uint32(struct nlattr nla, struct nl_pstate npt,
	+ const void arg, void target);
	+int nlattr_get_uint64(struct nlattr nla, struct nl_pstate npt,
	+ const void arg, void target);
	+int nlattr_get_ifp(struct nlattr nla, struct nl_pstate npt,
	+ const void arg, void target);
	+int nlattr_get_ifpz(struct nlattr nla, struct nl_pstate npt,
	+ const void arg, void target);
	+int nlattr_get_ipvia(struct nlattr nla, struct nl_pstate npt,
	+ const void arg, void target);
	+int nlattr_get_string(struct nlattr nla, struct nl_pstate npt,
	+ const void arg, void target);
	+int nlattr_get_stringn(struct nlattr nla, struct nl_pstate npt,
	+ const void arg, void target);
	+int nlattr_get_nla(struct nlattr nla, struct nl_pstate npt,
	+ const void arg, void target);
	+int nlattr_get_nested(struct nlattr nla, struct nl_pstate npt,
	+ const void arg, void target);
	+
	+bool nlmsg_report_err_msg(struct nl_pstate npt, const char fmt, ...);
	+
	+#define NLMSG_REPORT_ERR_MSG(_npt, _fmt, ...) { \
	+ nlmsg_report_err_msg(_npt, _fmt, ## __VA_ARGS__); \
	+ NLP_LOG(LOG_DEBUG, (_npt)->nlp, _fmt, ## __VA_ARGS__); \
	+}
	+
	+bool nlmsg_report_err_offset(struct nl_pstate *npt, uint32_t off);
	+
	+/*
	+ * Have it inline so compiler can optimize field accesses into
	+ * the list of direct function calls without iteration.
	+ */
	+static inline int
	+nl_parse_header(void hdr, int len, const struct nlhdr_parser parser,
	+ struct nl_pstate npt, void target)
	+{
	+ int error;
	+
	+ if (__predict_false(len < parser->nl_hdr_off)) {
	+ nlmsg_report_err_msg(npt, "header too short: expected %d, got %d",
	+ parser->nl_hdr_off, len);
	+ return (EINVAL);
	+ }
	+
	+ if (npt->strict && parser->sp != NULL && !parser->sp(hdr, npt))
	+ return (EINVAL);
	+
	+ /* Extract fields first */
	+ for (int i = 0; i < parser->fp_size; i++) {
	+ const struct nlfield_parser *fp = &parser->fp[i];
	+ void src = (char )hdr + fp->off_in;
	+ void dst = (char )target + fp->off_out;
	+
	+ error = fp->cb(src, npt, dst);
	+ if (error != 0)
	+ return (error);
	+ }
	+
	+ struct nlattr nla_head = (struct nlattr )((char *)hdr + parser->nl_hdr_off);
	+ error = nl_parse_attrs_raw(nla_head, len - parser->nl_hdr_off, parser->np,
	+ parser->np_size, npt, target);
	+
	+ return (error);
	+}
	+
	+static inline int
	+nl_parse_nested(struct nlattr nla, const struct nlhdr_parser parser,
	+ struct nl_pstate npt, void target)
	+{
	+ struct nlattr nla_head = (struct nlattr )NLA_DATA(nla);
	+
	+ return (nl_parse_attrs_raw(nla_head, NLA_DATA_LEN(nla), parser->np,
	+ parser->np_size, npt, target));
	+}
	+
	+/*
	+ * Checks that attributes are sorted by attribute type.
	+ */
	+static inline void
	+nl_verify_parsers(const struct nlhdr_parser **parser, int count)
	+{
	+ for (int i = 0; i < count; i++) {
	+ const struct nlhdr_parser *p = parser[i];
	+ int attr_type = 0;
	+ for (int j = 0; j < p->np_size; j++) {
	+ MPASS(p->np[j].type > attr_type);
	+ attr_type = p->np[j].type;
	+ }
	+ }
	+}
	+void nl_verify_parsers(const struct nlhdr_parser **parser, int count);
	+#define NL_VERIFY_PARSERS(_p) nl_verify_parsers((_p), NL_ARRAY_LEN(_p))
	+
	+static inline int
	+nl_parse_nlmsg(struct nlmsghdr hdr, const struct nlhdr_parser parser,
	+ struct nl_pstate npt, void target)
	+{
	+ return (nl_parse_header(hdr + 1, hdr->nlmsg_len - sizeof(*hdr), parser, npt, target));
	+}
	+
	+#endif
	diff --git a/sys/netlink/netlink_message_parser.c b/sys/netlink/netlink_message_parser.c
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/netlink_message_parser.c
	@@ -0,0 +1,472 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+#include <sys/cdefs.h>
	+__FBSDID("$FreeBSD$");
	+#include "opt_inet.h"
	+#include "opt_inet6.h"
	+#include <sys/types.h>
	+#include <sys/malloc.h>
	+#include <sys/rmlock.h>
	+#include <sys/socket.h>
	+
	+#include <machine/stdarg.h>
	+
	+#include <net/if.h>
	+#include <net/route.h>
	+#include <net/route/nhop.h>
	+
	+#include <net/route/route_ctl.h>
	+#include <netlink/netlink.h>
	+#include <netlink/netlink_ctl.h>
	+#include <netlink/netlink_var.h>
	+#include <netlink/netlink_route.h>
	+
	+#define DEBUG_MOD_NAME nl_parser
	+#define DEBUG_MAX_LEVEL LOG_DEBUG3
	+#include <netlink/netlink_debug.h>
	+_DECLARE_DEBUG(LOG_DEBUG);
	+
	+bool
	+nlmsg_report_err_msg(struct nl_pstate npt, const char fmt, ...)
	+{
	+ va_list ap;
	+
	+ if (npt->err_msg != NULL)
	+ return (false);
	+ char *buf = npt_alloc(npt, NL_MAX_ERROR_BUF);
	+ if (buf == NULL)
	+ return (false);
	+ va_start(ap, fmt);
	+ vsnprintf(buf, NL_MAX_ERROR_BUF, fmt, ap);
	+ va_end(ap);
	+
	+ npt->err_msg = buf;
	+ return (true);
	+}
	+
	+bool
	+nlmsg_report_err_offset(struct nl_pstate *npt, uint32_t off)
	+{
	+ if (npt->err_off != 0)
	+ return (false);
	+ npt->err_off = off;
	+ return (true);
	+}
	+
	+static const struct nlattr_parser *
	+search_states(const struct nlattr_parser *ps, int pslen, int key)
	+{
	+ int left_i = 0, right_i = pslen - 1;
	+
	+ if (key < ps[0].type \|\| key > ps[pslen - 1].type)
	+ return (NULL);
	+
	+ while (left_i + 1 < right_i) {
	+ int mid_i = (left_i + right_i) / 2;
	+ if (key < ps[mid_i].type)
	+ right_i = mid_i;
	+ else if (key > ps[mid_i].type)
	+ left_i = mid_i + 1;
	+ else
	+ return (&ps[mid_i]);
	+ }
	+ if (ps[left_i].type == key)
	+ return (&ps[left_i]);
	+ else if (ps[right_i].type == key)
	+ return (&ps[right_i]);
	+ return (NULL);
	+}
	+
	+int
	+nl_parse_attrs_raw(struct nlattr nla_head, int len, const struct nlattr_parser ps, int pslen,
	+ struct nl_pstate npt, void target)
	+{
	+ struct nlattr *nla = NULL;
	+ int error = 0;
	+
	+ NL_LOG(LOG_DEBUG3, "parse %p remaining_len %d", nla_head, len);
	+ int orig_len = len;
	+ NLA_FOREACH(nla, nla_head, len) {
	+ NL_LOG(LOG_DEBUG3, ">> parsing %p attr_type %d len %d (rem %d)", nla, nla->nla_type, nla->nla_len, len);
	+ if (nla->nla_len < sizeof(struct nlattr)) {
	+ NLMSG_REPORT_ERR_MSG(npt, "Invalid attr %p type %d len: %d",
	+ nla, nla->nla_type, nla->nla_len);
	+ uint32_t off = (char )nla - (char )npt->hdr;
	+ nlmsg_report_err_offset(npt, off);
	+ return (EINVAL);
	+ }
	+
	+ int nla_type = nla->nla_type & NLA_TYPE_MASK;
	+ const struct nlattr_parser *s = search_states(ps, pslen, nla_type);
	+ if (s != NULL) {
	+ void ptr = (void )((char *)target + s->off);
	+ error = s->cb(nla, npt, s->arg, ptr);
	+ if (error != 0) {
	+ uint32_t off = (char )nla - (char )npt->hdr;
	+ nlmsg_report_err_offset(npt, off);
	+ NL_LOG(LOG_DEBUG3, "parse failed att offset %u", off);
	+ return (error);
	+ }
	+ } else {
	+ /* Ignore non-specified attributes */
	+ NL_LOG(LOG_DEBUG3, "ignoring attr %d", nla->nla_type);
	+ }
	+ }
	+ if (len >= sizeof(struct nlattr)) {
	+ nla = (struct nlattr )((char )nla_head + (orig_len - len));
	+ NL_LOG(LOG_DEBUG3, " >>> end %p attr_type %d len %d", nla,
	+ nla->nla_type, nla->nla_len);
	+ }
	+ NL_LOG(LOG_DEBUG3, "end parse: %p remaining_len %d", nla, len);
	+
	+ return (0);
	+}
	+
	+int
	+nl_parse_attrs(struct nlmsghdr hdr, int hdrlen, struct nlattr_parser ps, int pslen,
	+ struct nl_pstate npt, void target)
	+{
	+ int off = NLMSG_HDRLEN + NETLINK_ALIGN(hdrlen);
	+ int len = hdr->nlmsg_len - off;
	+ struct nlattr nla_head = (struct nlattr )((char *)hdr + off);
	+
	+ return (nl_parse_attrs_raw(nla_head, len, ps, pslen, npt, target));
	+}
	+
	+int
	+nlattr_get_flag(struct nlattr nla, struct nl_pstate npt, const void arg, void target)
	+{
	+ if (__predict_false(NLA_DATA_LEN(nla) != 0)) {
	+ NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not a flag",
	+ nla->nla_type, NLA_DATA_LEN(nla));
	+ return (EINVAL);
	+ }
	+
	+ ((uint8_t )target) = 1;
	+ return (0);
	+}
	+
	+static struct sockaddr *
	+parse_rta_ip4(void rta_data, struct nl_pstate npt, int *perror)
	+{
	+ struct sockaddr_in *sin;
	+
	+ sin = (struct sockaddr_in *)npt_alloc_sockaddr(npt, sizeof(struct sockaddr_in));
	+ if (__predict_false(sin == NULL)) {
	+ *perror = ENOBUFS;
	+ return (NULL);
	+ }
	+ sin->sin_len = sizeof(struct sockaddr_in);
	+ sin->sin_family = AF_INET;
	+ memcpy(&sin->sin_addr, rta_data, sizeof(struct in_addr));
	+ return ((struct sockaddr *)sin);
	+}
	+
	+static struct sockaddr *
	+parse_rta_ip6(void rta_data, struct nl_pstate npt, int *perror)
	+{
	+ struct sockaddr_in6 *sin6;
	+
	+ sin6 = (struct sockaddr_in6 *)npt_alloc_sockaddr(npt, sizeof(struct sockaddr_in6));
	+ if (__predict_false(sin6 == NULL)) {
	+ *perror = ENOBUFS;
	+ return (NULL);
	+ }
	+ sin6->sin6_len = sizeof(struct sockaddr_in6);
	+ sin6->sin6_family = AF_INET6;
	+ memcpy(&sin6->sin6_addr, rta_data, sizeof(struct in6_addr));
	+ return ((struct sockaddr *)sin6);
	+}
	+
	+static struct sockaddr *
	+parse_rta_ip(struct rtattr rta, struct nl_pstate npt, int *perror)
	+{
	+ void *rta_data = NL_RTA_DATA(rta);
	+ int rta_len = NL_RTA_DATA_LEN(rta);
	+
	+ if (rta_len == sizeof(struct in_addr)) {
	+ return (parse_rta_ip4(rta_data, npt, perror));
	+ } else if (rta_len == sizeof(struct in6_addr)) {
	+ return (parse_rta_ip6(rta_data, npt, perror));
	+ } else {
	+ NLMSG_REPORT_ERR_MSG(npt, "unknown IP len: %d for rta type %d",
	+ rta_len, rta->rta_type);
	+ *perror = ENOTSUP;
	+ return (NULL);
	+ }
	+ return (NULL);
	+}
	+
	+int
	+nlattr_get_ip(struct nlattr nla, struct nl_pstate npt, const void arg, void target)
	+{
	+ int error = 0;
	+
	+ struct sockaddr sa = parse_rta_ip((struct rtattr )nla, npt, &error);
	+
	+ ((struct sockaddr *)target) = sa;
	+ return (error);
	+}
	+
	+static struct sockaddr *
	+parse_rta_via(struct rtattr rta, struct nl_pstate npt, int *perror)
	+{
	+ struct rtvia *via = NL_RTA_DATA(rta);
	+ int data_len = NL_RTA_DATA_LEN(rta);
	+
	+ if (__predict_false(data_len) < sizeof(struct rtvia)) {
	+ NLMSG_REPORT_ERR_MSG(npt, "undersized RTA_VIA(%d) attr: len %d",
	+ rta->rta_type, data_len);
	+ *perror = EINVAL;
	+ return (NULL);
	+ }
	+ data_len -= offsetof(struct rtvia, rtvia_addr);
	+
	+ switch (via->rtvia_family) {
	+ case AF_INET:
	+ if (__predict_false(data_len < sizeof(struct in_addr))) {
	+ *perror = EINVAL;
	+ return (NULL);
	+ }
	+ return (parse_rta_ip4(via->rtvia_addr, npt, perror));
	+ case AF_INET6:
	+ if (__predict_false(data_len < sizeof(struct in6_addr))) {
	+ *perror = EINVAL;
	+ return (NULL);
	+ }
	+ return (parse_rta_ip6(via->rtvia_addr, npt, perror));
	+ default:
	+ *perror = ENOTSUP;
	+ return (NULL);
	+ }
	+}
	+
	+int
	+nlattr_get_ipvia(struct nlattr nla, struct nl_pstate npt, const void arg, void target)
	+{
	+ int error = 0;
	+
	+ struct sockaddr sa = parse_rta_via((struct rtattr )nla, npt, &error);
	+
	+ ((struct sockaddr *)target) = sa;
	+ return (error);
	+}
	+
	+
	+int
	+nlattr_get_uint16(struct nlattr nla, struct nl_pstate npt, const void arg, void target)
	+{
	+ if (__predict_false(NLA_DATA_LEN(nla) != sizeof(uint16_t))) {
	+ NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not uint32",
	+ nla->nla_type, NLA_DATA_LEN(nla));
	+ return (EINVAL);
	+ }
	+ ((uint16_t )target) = ((const uint16_t )NL_RTA_DATA_CONST(nla));
	+ return (0);
	+}
	+
	+int
	+nlattr_get_uint32(struct nlattr nla, struct nl_pstate npt, const void arg, void target)
	+{
	+ if (__predict_false(NLA_DATA_LEN(nla) != sizeof(uint32_t))) {
	+ NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not uint32",
	+ nla->nla_type, NLA_DATA_LEN(nla));
	+ return (EINVAL);
	+ }
	+ ((uint32_t )target) = ((const uint32_t )NL_RTA_DATA_CONST(nla));
	+ return (0);
	+}
	+
	+int
	+nlattr_get_uint64(struct nlattr nla, struct nl_pstate npt, const void arg, void target)
	+{
	+ if (__predict_false(NLA_DATA_LEN(nla) != sizeof(uint64_t))) {
	+ NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not uint64",
	+ nla->nla_type, NLA_DATA_LEN(nla));
	+ return (EINVAL);
	+ }
	+ memcpy(target, NL_RTA_DATA_CONST(nla), sizeof(uint64_t));
	+ return (0);
	+}
	+
	+static int
	+nlattr_get_ifp_internal(struct nlattr nla, struct nl_pstate npt,
	+ void *target, bool zero_ok)
	+{
	+ if (__predict_false(NLA_DATA_LEN(nla) != sizeof(uint32_t))) {
	+ NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not uint32",
	+ nla->nla_type, NLA_DATA_LEN(nla));
	+ return (EINVAL);
	+ }
	+ uint32_t ifindex = ((const uint32_t )NLA_DATA_CONST(nla));
	+
	+ if (ifindex == 0 && zero_ok) {
	+ ((struct ifnet *)target) = NULL;
	+ return (0);
	+ }
	+
	+ NET_EPOCH_ASSERT();
	+
	+ struct ifnet *ifp = ifnet_byindex(ifindex);
	+ if (__predict_false(ifp == NULL)) {
	+ NLMSG_REPORT_ERR_MSG(npt, "nla type %d: ifindex %u invalid",
	+ nla->nla_type, ifindex);
	+ return (ENOENT);
	+ }
	+ ((struct ifnet *)target) = ifp;
	+ NL_LOG(LOG_DEBUG3, "nla type %d: ifindex %u -> %s", nla->nla_type,
	+ ifindex, if_name(ifp));
	+
	+ return (0);
	+}
	+
	+int
	+nlattr_get_ifp(struct nlattr nla, struct nl_pstate npt, const void arg, void target)
	+{
	+ return (nlattr_get_ifp_internal(nla, npt, target, false));
	+}
	+
	+int
	+nlattr_get_ifpz(struct nlattr nla, struct nl_pstate npt, const void arg, void target)
	+{
	+ return (nlattr_get_ifp_internal(nla, npt, target, true));
	+}
	+
	+int
	+nlattr_get_string(struct nlattr nla, struct nl_pstate npt, const void arg, void target)
	+{
	+ int maxlen = NLA_DATA_LEN(nla);
	+
	+ if (__predict_false(strnlen((char *)NLA_DATA(nla), maxlen) >= maxlen)) {
	+ NLMSG_REPORT_ERR_MSG(npt, "nla type %d size(%u) is not NULL-terminated",
	+ nla->nla_type, maxlen);
	+ return (EINVAL);
	+ }
	+
	+ ((char )target) = (char )NLA_DATA(nla);
	+ return (0);
	+}
	+
	+int
	+nlattr_get_stringn(struct nlattr nla, struct nl_pstate npt, const void arg, void target)
	+{
	+ int maxlen = NLA_DATA_LEN(nla);
	+
	+ char *buf = npt_alloc(npt, maxlen + 1);
	+ if (buf == NULL)
	+ return (ENOMEM);
	+ buf[maxlen] = '\0';
	+ memcpy(buf, NLA_DATA(nla), maxlen);
	+
	+ ((char *)target) = buf;
	+ return (0);
	+}
	+int
	+nlattr_get_nla(struct nlattr nla, struct nl_pstate npt, const void arg, void target)
	+{
	+ NL_LOG(LOG_DEBUG3, "STORING %p len %d", nla, nla->nla_len);
	+ ((struct nlattr *)target) = nla;
	+ return (0);
	+}
	+
	+int
	+nlattr_get_nested(struct nlattr nla, struct nl_pstate npt, const void arg, void target)
	+{
	+ const struct nlhdr_parser p = (const struct nlhdr_parser )arg;
	+ int error;
	+
	+ /* Assumes target points to the beginning of the structure */
	+ error = nl_parse_header(NLA_DATA(nla), NLA_DATA_LEN(nla), p, npt, target);
	+ return (error);
	+}
	+
	+int
	+nlf_get_ifp(void src, struct nl_pstate npt, void *target)
	+{
	+ int ifindex = ((const int )src);
	+
	+ NET_EPOCH_ASSERT();
	+
	+ struct ifnet *ifp = ifnet_byindex(ifindex);
	+ if (ifp == NULL) {
	+ NL_LOG(LOG_DEBUG, "ifindex %u invalid", ifindex);
	+ return (ENOENT);
	+ }
	+ ((struct ifnet *)target) = ifp;
	+
	+ return (0);
	+}
	+
	+int
	+nlf_get_ifpz(void src, struct nl_pstate npt, void *target)
	+{
	+ int ifindex = ((const int )src);
	+
	+ NET_EPOCH_ASSERT();
	+
	+ struct ifnet *ifp = ifnet_byindex(ifindex);
	+ if (ifindex != 0 && ifp == NULL) {
	+ NL_LOG(LOG_DEBUG, "ifindex %u invalid", ifindex);
	+ return (ENOENT);
	+ }
	+ ((struct ifnet *)target) = ifp;
	+
	+ return (0);
	+}
	+
	+int
	+nlf_get_u8(void src, struct nl_pstate npt, void *target)
	+{
	+ uint8_t val = ((const uint8_t )src);
	+
	+ ((uint8_t )target) = val;
	+
	+ return (0);
	+}
	+
	+int
	+nlf_get_u8_u32(void src, struct nl_pstate npt, void *target)
	+{
	+ ((uint32_t )target) = ((const uint8_t )src);
	+ return (0);
	+}
	+
	+int
	+nlf_get_u16(void src, struct nl_pstate npt, void *target)
	+{
	+ ((uint16_t )target) = ((const uint16_t )src);
	+ return (0);
	+}
	+
	+int
	+nlf_get_u32(void src, struct nl_pstate npt, void *target)
	+{
	+ ((uint32_t )target) = ((const uint32_t )src);
	+ return (0);
	+}
	+
	diff --git a/sys/netlink/netlink_message_writer.h b/sys/netlink/netlink_message_writer.h
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/netlink_message_writer.h
	@@ -0,0 +1,250 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2021 Ng Peng Nam Sean
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+#ifndef _NETLINK_NETLINK_MESSAGE_WRITER_H_
	+#define _NETLINK_NETLINK_MESSAGE_WRITER_H_
	+
	+/*
	+ * It is not meant to be included directly
	+ */
	+
	+struct mbuf;
	+struct nl_writer;
	+typedef bool nl_writer_cb(struct nl_writer nw, void buf, int buflen, int cnt);
	+
	+struct nl_writer {
	+ int alloc_len; /* allocated buffer length */
	+ int offset; /* offset from the start of the buffer */
	+ struct nlmsghdr hdr; / Pointer to the currently-filled msg */
	+ char data; / pointer to the contiguous storage */
	+ void _storage; / Underlying storage pointer */
	+ nl_writer_cb cb; / Callback to flush data */
	+ union {
	+ void arg_ptr; / Callback argument as pointer */
	+ uint64_t arg_uint; /* Callback argument as int */
	+ };
	+ int num_messages; /* Number of messages in the buffer */
	+ int malloc_flag; /* M_WAITOK or M_NOWAIT */
	+ uint8_t writer_type; /* NS_WRITER_TYPE_* */
	+ uint8_t writer_target; /* NS_WRITER_TARGET_* */
	+ bool ignore_limit; /* If true, ignores RCVBUF limit */
	+ bool enomem; /* True if ENOMEM occured */
	+};
	+#define NS_WRITER_TARGET_SOCKET 0
	+#define NS_WRITER_TARGET_GROUP 1
	+#define NS_WRITER_TARGET_CHAIN 2
	+
	+#define NS_WRITER_TYPE_MBUF 0
	+#define NS_WRITER_TYPE_BUF 1
	+#define NS_WRITER_TYPE_LBUF 2
	+#define NS_WRITER_TYPE_MBUFC 3
	+
	+
	+#define NLMSG_SMALL 128
	+#define NLMSG_LARGE 2048
	+
	+/* Message and attribute writing */
	+
	+struct nlpcb;
	+bool nlmsg_get_unicast_writer(struct nl_writer nw, int expected_size, struct nlpcb nlp);
	+bool nlmsg_get_group_writer(struct nl_writer *nw, int expected_size, int proto, int group_id);
	+bool nlmsg_get_chain_writer(struct nl_writer nw, int expected_size, struct mbuf *pm);
	+bool nlmsg_flush(struct nl_writer *nw);
	+void nlmsg_ignore_limit(struct nl_writer *nw);
	+
	+bool nlmsg_refill_buffer(struct nl_writer *nw, int required_size);
	+bool nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type,
	+ uint16_t flags, uint32_t len);
	+bool nlmsg_end(struct nl_writer *nw);
	+void nlmsg_abort(struct nl_writer *nw);
	+
	+bool nlmsg_end_dump(struct nl_writer nw, int error, struct nlmsghdr hdr);
	+
	+static inline bool
	+nlmsg_reply(struct nl_writer nw, const struct nlmsghdr hdr, int payload_len)
	+{
	+ return (nlmsg_add(nw, hdr->nlmsg_pid, hdr->nlmsg_seq, hdr->nlmsg_type,
	+ hdr->nlmsg_flags, payload_len));
	+}
	+
	+#define nlmsg_data(_hdr) ((void *)((_hdr) + 1))
	+
	+/*
	+ * KPI similar to mtodo():
	+ * current (uncompleted) header is guaranteed to be contiguous,
	+ * but can be reallocated, thus pointers may need to be readjusted.
	+ */
	+static inline int
	+nlattr_save_offset(const struct nl_writer *nw)
	+{
	+ return (nw->offset - ((char *)nw->hdr - nw->data));
	+}
	+
	+static inline void *
	+_nlattr_restore_offset(const struct nl_writer *nw, int off)
	+{
	+ return ((void )((char )nw->hdr + off));
	+}
	+#define nlattr_restore_offset(_ns, _off, _t) ((_t *)_nlattr_restore_offset(_ns, _off))
	+
	+static inline void
	+nlattr_set_len(const struct nl_writer *nw, int off)
	+{
	+ struct nlattr *nla = nlattr_restore_offset(nw, off, struct nlattr);
	+ nla->nla_len = nlattr_save_offset(nw) - off;
	+}
	+
	+static inline void *
	+nlmsg_reserve_data_raw(struct nl_writer *nw, size_t sz)
	+{
	+ if (__predict_false(nw->offset + NETLINK_ALIGN(sz) > nw->alloc_len)) {
	+ if (!nlmsg_refill_buffer(nw, NETLINK_ALIGN(sz)))
	+ return (NULL);
	+ }
	+
	+ void *data_ptr = &nw->data[nw->offset];
	+ nw->offset += NLMSG_ALIGN(sz);
	+
	+ return (data_ptr);
	+}
	+#define nlmsg_reserve_object(_ns, _t) ((_t *)nlmsg_reserve_data_raw(_ns, NLA_ALIGN(sizeof(_t))))
	+#define nlmsg_reserve_data(_ns, _sz, _t) ((_t *)nlmsg_reserve_data_raw(_ns, _sz))
	+
	+static inline int
	+nlattr_add_nested(struct nl_writer *nw, uint16_t nla_type)
	+{
	+ int off = nlattr_save_offset(nw);
	+ struct nlattr *nla = nlmsg_reserve_data(nw, sizeof(struct nlattr), struct nlattr);
	+ if (__predict_false(nla == NULL))
	+ return (0);
	+ nla->nla_type = nla_type;
	+ return (off);
	+}
	+
	+static inline void *
	+_nlmsg_reserve_attr(struct nl_writer *nw, uint16_t nla_type, uint16_t sz)
	+{
	+ sz += sizeof(struct nlattr);
	+
	+ struct nlattr *nla = nlmsg_reserve_data(nw, sz, struct nlattr);
	+ if (__predict_false(nla == NULL))
	+ return (NULL);
	+ nla->nla_type = nla_type;
	+ nla->nla_len = sz;
	+
	+ return ((void *)(nla + 1));
	+}
	+#define nlmsg_reserve_attr(_ns, _at, _t) ((_t *)_nlmsg_reserve_attr(_ns, _at, NLA_ALIGN(sizeof(_t))))
	+
	+static inline bool
	+nlattr_add(struct nl_writer nw, int attr_type, int attr_len, const void data)
	+{
	+ int required_len = NLA_ALIGN(attr_len + sizeof(struct nlattr));
	+
	+ if (__predict_false(nw->offset + required_len > nw->alloc_len)) {
	+ if (!nlmsg_refill_buffer(nw, required_len))
	+ return (false);
	+ }
	+
	+ struct nlattr nla = (struct nlattr )(&nw->data[nw->offset]);
	+
	+ nla->nla_len = attr_len + sizeof(struct nlattr);
	+ nla->nla_type = attr_type;
	+ if (attr_len > 0) {
	+ if ((attr_len % 4) != 0) {
	+ /* clear padding bytes */
	+ bzero((char *)nla + required_len - 4, 4);
	+ }
	+ memcpy((nla + 1), data, attr_len);
	+ }
	+ nw->offset += required_len;
	+ return (true);
	+}
	+
	+static inline bool
	+nlattr_add_u8(struct nl_writer *nw, int attrtype, uint8_t value)
	+{
	+ return (nlattr_add(nw, attrtype, sizeof(uint8_t), &value));
	+}
	+
	+static inline bool
	+nlattr_add_u16(struct nl_writer *nw, int attrtype, uint16_t value)
	+{
	+ return (nlattr_add(nw, attrtype, sizeof(uint16_t), &value));
	+}
	+
	+static inline bool
	+nlattr_add_u32(struct nl_writer *nw, int attrtype, uint32_t value)
	+{
	+ return (nlattr_add(nw, attrtype, sizeof(uint32_t), &value));
	+}
	+
	+static inline bool
	+nlattr_add_u64(struct nl_writer *nw, int attrtype, uint64_t value)
	+{
	+ return (nlattr_add(nw, attrtype, sizeof(uint64_t), &value));
	+}
	+
	+static inline bool
	+nlattr_add_s8(struct nl_writer *nw, int attrtype, int8_t value)
	+{
	+ return (nlattr_add(nw, attrtype, sizeof(int8_t), &value));
	+}
	+
	+static inline bool
	+nlattr_add_s16(struct nl_writer *nw, int attrtype, int16_t value)
	+{
	+ return (nlattr_add(nw, attrtype, sizeof(int16_t), &value));
	+}
	+
	+static inline bool
	+nlattr_add_s32(struct nl_writer *nw, int attrtype, int32_t value)
	+{
	+ return (nlattr_add(nw, attrtype, sizeof(int32_t), &value));
	+}
	+
	+static inline bool
	+nlattr_add_s64(struct nl_writer *nw, int attrtype, int64_t value)
	+{
	+ return (nlattr_add(nw, attrtype, sizeof(int64_t), &value));
	+}
	+
	+static inline bool
	+nlattr_add_flag(struct nl_writer *nw, int attrtype)
	+{
	+ return (nlattr_add(nw, attrtype, 0, NULL));
	+}
	+
	+static inline bool
	+nlattr_add_string(struct nl_writer nw, int attrtype, const char str)
	+{
	+ return (nlattr_add(nw, attrtype, strlen(str) + 1, str));
	+}
	+
	+
	+#endif
	diff --git a/sys/netlink/netlink_message_writer.c b/sys/netlink/netlink_message_writer.c
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/netlink_message_writer.c
	@@ -0,0 +1,686 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+#include <sys/cdefs.h>
	+__FBSDID("$FreeBSD$");
	+#include <sys/param.h>
	+#include <sys/malloc.h>
	+#include <sys/lock.h>
	+#include <sys/rmlock.h>
	+#include <sys/mbuf.h>
	+#include <sys/ck.h>
	+#include <sys/socket.h>
	+#include <sys/socketvar.h>
	+#include <sys/syslog.h>
	+
	+#include <netlink/netlink.h>
	+#include <netlink/netlink_ctl.h>
	+#include <netlink/netlink_linux.h>
	+#include <netlink/netlink_var.h>
	+
	+#define DEBUG_MOD_NAME nl_writer
	+#define DEBUG_MAX_LEVEL LOG_DEBUG3
	+#include <netlink/netlink_debug.h>
	+_DECLARE_DEBUG(LOG_DEBUG);
	+
	+/*
	+ * The goal of this file is to provide convenient message writing KPI on top of
	+ * different storage methods (mbufs, uio, temporary memory chunks).
	+ *
	+ * The main KPI guarantee is the the (last) message always resides in the contiguous
	+ * memory buffer, so one is able to update the header after writing the entire message.
	+ *
	+ * This guarantee comes with a side effect of potentially reallocating underlying
	+ * buffer, so one needs to update the desired pointers after something is added
	+ * to the header.
	+ *
	+ * Messaging layer contains hooks performing transparent Linux translation for the messages.
	+ *
	+ * There are 3 types of supported targets:
	+ * * socket (adds mbufs to the socket buffer, used for message replies)
	+ * * group (sends mbuf/chain to the specified groups, used for the notifications)
	+ * * chain (returns mbuf chain, used in Linux message translation code)
	+ *
	+ * There are 3 types of storage:
	+ * * NS_WRITER_TYPE_MBUF (mbuf-based, most efficient, used when a single message
	+ * fits in MCLBYTES)
	+ * * NS_WRITER_TYPE_BUF (fallback, malloc-based, used when a single message needs
	+ * to be larger than one supported by NS_WRITER_TYPE_MBUF)
	+ * * NS_WRITER_TYPE_LBUF (malloc-based, similar to NS_WRITER_TYPE_BUF, used for
	+ * Linux sockets, calls translation hook prior to sending messages to the socket).
	+ *
	+ * Internally, KPI switches between different types of storage when memory requirements
	+ * change. It happens transparently to the caller.
	+ */
	+
	+
	+typedef bool nlwriter_op_init(struct nl_writer *nw, int size, bool waitok);
	+typedef bool nlwriter_op_write(struct nl_writer nw, void buf, int buflen, int cnt);
	+
	+struct nlwriter_ops {
	+ nlwriter_op_init *init;
	+ nlwriter_op_write *write_socket;
	+ nlwriter_op_write *write_group;
	+ nlwriter_op_write *write_chain;
	+};
	+
	+/*
	+ * NS_WRITER_TYPE_BUF
	+ * Writes message to a temporary memory buffer,
	+ * flushing to the socket/group when buffer size limit is reached
	+ */
	+static bool
	+nlmsg_get_ns_buf(struct nl_writer *nw, int size, bool waitok)
	+{
	+ int mflag = waitok ? M_WAITOK : M_NOWAIT;
	+ nw->_storage = malloc(size, M_NETLINK, mflag \| M_ZERO);
	+ if (__predict_false(nw->_storage == NULL))
	+ return (false);
	+ nw->alloc_len = size;
	+ nw->offset = 0;
	+ nw->hdr = NULL;
	+ nw->data = nw->_storage;
	+ nw->writer_type = NS_WRITER_TYPE_BUF;
	+ nw->malloc_flag = mflag;
	+ nw->num_messages = 0;
	+ nw->enomem = false;
	+ return (true);
	+}
	+
	+static bool
	+nlmsg_write_socket_buf(struct nl_writer nw, void buf, int datalen, int cnt)
	+{
	+ NL_LOG(LOG_DEBUG2, "IN: ptr: %p len: %d arg: %p", buf, datalen, nw);
	+ if (__predict_false(datalen == 0)) {
	+ free(buf, M_NETLINK);
	+ return (true);
	+ }
	+
	+ struct mbuf *m = m_getm2(NULL, datalen, nw->malloc_flag, MT_DATA, M_PKTHDR);
	+ if (__predict_false(m == NULL)) {
	+ /* XXX: should we set sorcverr? */
	+ free(buf, M_NETLINK);
	+ return (false);
	+ }
	+ m_append(m, datalen, buf);
	+ free(buf, M_NETLINK);
	+
	+ int io_flags = (nw->ignore_limit) ? NL_IOF_IGNORE_LIMIT : 0;
	+ return (nl_send_one(m, (struct nlpcb *)(nw->arg_ptr), cnt, io_flags));
	+}
	+
	+static bool
	+nlmsg_write_group_buf(struct nl_writer nw, void buf, int datalen, int cnt)
	+{
	+ NL_LOG(LOG_DEBUG2, "IN: ptr: %p len: %d arg: %p", buf, datalen, nw->arg_ptr);
	+ if (__predict_false(datalen == 0)) {
	+ free(buf, M_NETLINK);
	+ return (true);
	+ }
	+
	+ struct mbuf *m = m_getm2(NULL, datalen, nw->malloc_flag, MT_DATA, M_PKTHDR);
	+ if (__predict_false(m == NULL)) {
	+ free(buf, M_NETLINK);
	+ return (false);
	+ }
	+ bool success = m_append(m, datalen, buf) != 0;
	+ free(buf, M_NETLINK);
	+
	+ if (!success)
	+ return (false);
	+
	+ nl_send_group(m, cnt, nw->arg_uint >> 16, nw->arg_uint & 0xFFFF);
	+ return (true);
	+}
	+
	+static bool
	+nlmsg_write_chain_buf(struct nl_writer nw, void buf, int datalen, int cnt)
	+{
	+ struct mbuf m0 = (struct mbuf )(nw->arg_ptr);
	+ NL_LOG(LOG_DEBUG2, "IN: ptr: %p len: %d arg: %p", buf, datalen, nw->arg_ptr);
	+
	+ if (__predict_false(datalen == 0)) {
	+ free(buf, M_NETLINK);
	+ return (true);
	+ }
	+
	+ if (*m0 == NULL) {
	+ struct mbuf *m;
	+
	+ m = m_getm2(NULL, datalen, nw->malloc_flag, MT_DATA, M_PKTHDR);
	+ if (__predict_false(m == NULL)) {
	+ free(buf, M_NETLINK);
	+ return (false);
	+ }
	+ *m0 = m;
	+ }
	+ if (__predict_false(m_append(*m0, datalen, buf) == 0)) {
	+ free(buf, M_NETLINK);
	+ return (false);
	+ }
	+ return (true);
	+}
	+
	+
	+/*
	+ * NS_WRITER_TYPE_MBUF
	+ * Writes message to the allocated mbuf,
	+ * flushing to socket/group when mbuf size limit is reached.
	+ * This is the most efficient mechanism as it avoids double-copying.
	+ *
	+ * Allocates a single mbuf suitable to store up to @size bytes of data.
	+ * If size < MHLEN (around 160 bytes), allocates mbuf with pkghdr
	+ * If size <= MCLBYTES (2k), allocate a single mbuf cluster
	+ * Otherwise, return NULL.
	+ */
	+static bool
	+nlmsg_get_ns_mbuf(struct nl_writer *nw, int size, bool waitok)
	+{
	+ struct mbuf *m;
	+
	+ int mflag = waitok ? M_WAITOK : M_NOWAIT;
	+ m = m_get2(size, mflag, MT_DATA, M_PKTHDR);
	+ if (__predict_false(m == NULL))
	+ return (false);
	+ nw->alloc_len = M_TRAILINGSPACE(m);
	+ nw->offset = 0;
	+ nw->hdr = NULL;
	+ nw->_storage = (void *)m;
	+ nw->data = mtod(m, void *);
	+ nw->writer_type = NS_WRITER_TYPE_MBUF;
	+ nw->malloc_flag = mflag;
	+ nw->num_messages = 0;
	+ nw->enomem = false;
	+ NL_LOG(LOG_DEBUG2, "alloc mbuf %p req_len %d alloc_len %d data_ptr %p",
	+ m, size, nw->alloc_len, nw->data);
	+ return (true);
	+}
	+
	+static bool
	+nlmsg_write_socket_mbuf(struct nl_writer nw, void buf, int datalen, int cnt)
	+{
	+ struct mbuf m = (struct mbuf )buf;
	+ NL_LOG(LOG_DEBUG2, "IN: ptr: %p len: %d arg: %p", buf, datalen, nw->arg_ptr);
	+
	+ if (__predict_false(datalen == 0)) {
	+ m_freem(m);
	+ return (true);
	+ }
	+
	+ m->m_pkthdr.len = datalen;
	+ m->m_len = datalen;
	+ int io_flags = (nw->ignore_limit) ? NL_IOF_IGNORE_LIMIT : 0;
	+ return (nl_send_one(m, (struct nlpcb *)(nw->arg_ptr), cnt, io_flags));
	+}
	+
	+static bool
	+nlmsg_write_group_mbuf(struct nl_writer nw, void buf, int datalen, int cnt)
	+{
	+ struct mbuf m = (struct mbuf )buf;
	+ NL_LOG(LOG_DEBUG2, "IN: ptr: %p len: %d arg: %p", buf, datalen, nw->arg_ptr);
	+
	+ if (__predict_false(datalen == 0)) {
	+ m_freem(m);
	+ return (true);
	+ }
	+
	+ m->m_pkthdr.len = datalen;
	+ m->m_len = datalen;
	+ nl_send_group(m, cnt, nw->arg_uint >> 16, nw->arg_uint & 0xFFFF);
	+ return (true);
	+}
	+
	+static bool
	+nlmsg_write_chain_mbuf(struct nl_writer nw, void buf, int datalen, int cnt)
	+{
	+ struct mbuf m_new = (struct mbuf )buf;
	+ struct mbuf m0 = (struct mbuf )(nw->arg_ptr);
	+
	+ NL_LOG(LOG_DEBUG2, "IN: ptr: %p len: %d arg: %p", buf, datalen, nw->arg_ptr);
	+
	+ if (__predict_false(datalen == 0)) {
	+ m_freem(m_new);
	+ return (true);
	+ }
	+
	+ m_new->m_pkthdr.len = datalen;
	+ m_new->m_len = datalen;
	+
	+ if (*m0 == NULL) {
	+ *m0 = m_new;
	+ } else {
	+ struct mbuf *m_last;
	+ for (m_last = *m0; m_last->m_next != NULL; m_last = m_last->m_next)
	+ ;
	+ m_last->m_next = m_new;
	+ (*m0)->m_pkthdr.len += datalen;
	+ }
	+
	+ return (true);
	+}
	+
	+/*
	+ * NS_WRITER_TYPE_LBUF
	+ * Writes message to the allocated memory buffer,
	+ * flushing to socket/group when mbuf size limit is reached.
	+ * Calls linux handler to rewrite messages before sending to the socket.
	+ */
	+static bool
	+nlmsg_get_ns_lbuf(struct nl_writer *nw, int size, bool waitok)
	+{
	+ int mflag = waitok ? M_WAITOK : M_NOWAIT;
	+ size = roundup2(size, sizeof(void *));
	+ int add_size = sizeof(struct linear_buffer) + SCRATCH_BUFFER_SIZE;
	+ char buf = malloc(add_size + size 2, M_NETLINK, mflag \| M_ZERO);
	+ if (__predict_false(buf == NULL))
	+ return (false);
	+
	+ /* Fill buffer header first */
	+ struct linear_buffer lb = (struct linear_buffer )buf;
	+ lb->base = &buf[sizeof(struct linear_buffer) + size];
	+ lb->size = size + SCRATCH_BUFFER_SIZE;
	+
	+ nw->alloc_len = size;
	+ nw->offset = 0;
	+ nw->hdr = NULL;
	+ nw->_storage = buf;
	+ nw->data = (char *)(lb + 1);
	+ nw->malloc_flag = mflag;
	+ nw->writer_type = NS_WRITER_TYPE_LBUF;
	+ nw->num_messages = 0;
	+ nw->enomem = false;
	+ return (true);
	+}
	+
	+
	+static bool
	+nlmsg_write_socket_lbuf(struct nl_writer nw, void buf, int datalen, int cnt)
	+{
	+ struct linear_buffer lb = (struct linear_buffer )buf;
	+ char data = (char )(lb + 1);
	+ struct nlpcb nlp = (struct nlpcb )(nw->arg_ptr);
	+
	+ if (__predict_false(datalen == 0)) {
	+ free(buf, M_NETLINK);
	+ return (true);
	+ }
	+
	+ struct mbuf *m = NULL;
	+ if (linux_netlink_p != NULL)
	+ m = linux_netlink_p->msgs_to_linux(nlp->nl_proto, data, datalen, nlp);
	+ free(buf, M_NETLINK);
	+
	+ if (__predict_false(m == NULL)) {
	+ /* XXX: should we set sorcverr? */
	+ return (false);
	+ }
	+
	+ int io_flags = (nw->ignore_limit) ? NL_IOF_IGNORE_LIMIT : 0;
	+ return (nl_send_one(m, nlp, cnt, io_flags));
	+}
	+
	+/* Shouldn't be called (maybe except Linux code originating message) */
	+static bool
	+nlmsg_write_group_lbuf(struct nl_writer nw, void buf, int datalen, int cnt)
	+{
	+ struct linear_buffer lb = (struct linear_buffer )buf;
	+ char data = (char )(lb + 1);
	+
	+ if (__predict_false(datalen == 0)) {
	+ free(buf, M_NETLINK);
	+ return (true);
	+ }
	+
	+ struct mbuf *m = m_getm2(NULL, datalen, nw->malloc_flag, MT_DATA, M_PKTHDR);
	+ if (__predict_false(m == NULL)) {
	+ free(buf, M_NETLINK);
	+ return (false);
	+ }
	+ m_append(m, datalen, data);
	+ free(buf, M_NETLINK);
	+
	+ nl_send_group(m, cnt, nw->arg_uint >> 16, nw->arg_uint & 0xFFFF);
	+ return (true);
	+}
	+
	+struct nlwriter_ops nlmsg_writers[] = {
	+ /* NS_WRITER_TYPE_MBUF */
	+ {
	+ .init = nlmsg_get_ns_mbuf,
	+ .write_socket = nlmsg_write_socket_mbuf,
	+ .write_group = nlmsg_write_group_mbuf,
	+ .write_chain = nlmsg_write_chain_mbuf,
	+ },
	+ /* NS_WRITER_TYPE_BUF */
	+ {
	+ .init = nlmsg_get_ns_buf,
	+ .write_socket = nlmsg_write_socket_buf,
	+ .write_group = nlmsg_write_group_buf,
	+ .write_chain = nlmsg_write_chain_buf,
	+ },
	+ /* NS_WRITER_TYPE_LBUF */
	+ {
	+ .init = nlmsg_get_ns_lbuf,
	+ .write_socket = nlmsg_write_socket_lbuf,
	+ .write_group = nlmsg_write_group_lbuf,
	+ },
	+};
	+
	+static void
	+nlmsg_set_callback(struct nl_writer *nw)
	+{
	+ struct nlwriter_ops *pops = &nlmsg_writers[nw->writer_type];
	+
	+ switch (nw->writer_target) {
	+ case NS_WRITER_TARGET_SOCKET:
	+ nw->cb = pops->write_socket;
	+ break;
	+ case NS_WRITER_TARGET_GROUP:
	+ nw->cb = pops->write_group;
	+ break;
	+ case NS_WRITER_TARGET_CHAIN:
	+ nw->cb = pops->write_chain;
	+ break;
	+ default:
	+ panic("not implemented");
	+ }
	+}
	+
	+static bool
	+nlmsg_get_buf_type(struct nl_writer *nw, int size, int type, bool waitok)
	+{
	+ MPASS(type + 1 <= sizeof(nlmsg_writers) / sizeof(nlmsg_writers[0]));
	+ NL_LOG(LOG_DEBUG3, "Setting up nw %p size %d type %d", nw, size, type);
	+ return (nlmsg_writers[type].init(nw, size, waitok));
	+}
	+
	+static bool
	+nlmsg_get_buf(struct nl_writer *nw, int size, bool waitok, bool is_linux)
	+{
	+ int type;
	+
	+ if (!is_linux) {
	+ if (__predict_true(size <= MCLBYTES))
	+ type = NS_WRITER_TYPE_MBUF;
	+ else
	+ type = NS_WRITER_TYPE_BUF;
	+ } else
	+ type = NS_WRITER_TYPE_LBUF;
	+ return (nlmsg_get_buf_type(nw, size, type, waitok));
	+}
	+
	+bool
	+nlmsg_get_unicast_writer(struct nl_writer nw, int size, struct nlpcb nlp)
	+{
	+ if (!nlmsg_get_buf(nw, size, false, nlp->nl_linux))
	+ return (false);
	+ nw->arg_ptr = (void *)nlp;
	+ nw->writer_target = NS_WRITER_TARGET_SOCKET;
	+ nlmsg_set_callback(nw);
	+ return (true);
	+}
	+
	+bool
	+nlmsg_get_group_writer(struct nl_writer *nw, int size, int protocol, int group_id)
	+{
	+ if (!nlmsg_get_buf(nw, size, false, false))
	+ return (false);
	+ nw->arg_uint = (uint64_t)protocol << 16 \| (uint64_t)group_id;
	+ nw->writer_target = NS_WRITER_TARGET_GROUP;
	+ nlmsg_set_callback(nw);
	+ return (true);
	+}
	+
	+bool
	+nlmsg_get_chain_writer(struct nl_writer nw, int size, struct mbuf *pm)
	+{
	+ if (!nlmsg_get_buf(nw, size, false, false))
	+ return (false);
	+ *pm = NULL;
	+ nw->arg_ptr = (void *)pm;
	+ nw->writer_target = NS_WRITER_TARGET_CHAIN;
	+ nlmsg_set_callback(nw);
	+ NL_LOG(LOG_DEBUG3, "setup cb %p (need %p)", nw->cb, &nlmsg_write_chain_mbuf);
	+ return (true);
	+}
	+
	+void
	+nlmsg_ignore_limit(struct nl_writer *nw)
	+{
	+ nw->ignore_limit = true;
	+}
	+
	+bool
	+nlmsg_flush(struct nl_writer *nw)
	+{
	+
	+ if (__predict_false(nw->hdr != NULL)) {
	+ /* Last message has not been completed, skip it. */
	+ int completed_len = (char *)nw->hdr - nw->data;
	+ /* Send completed messages */
	+ nw->offset -= nw->offset - completed_len;
	+ nw->hdr = NULL;
	+ }
	+
	+ NL_LOG(LOG_DEBUG2, "OUT");
	+ bool result = nw->cb(nw, nw->_storage, nw->offset, nw->num_messages);
	+ nw->_storage = NULL;
	+
	+ if (!result) {
	+ NL_LOG(LOG_DEBUG, "nw %p offset %d: flush with %p() failed", nw, nw->offset, nw->cb);
	+ }
	+
	+ return (result);
	+}
	+
	+/*
	+ * Flushes previous data and allocates new underlying storage
	+ * sufficient for holding at least @required_len bytes.
	+ * Return true on success.
	+ */
	+bool
	+nlmsg_refill_buffer(struct nl_writer *nw, int required_len)
	+{
	+ struct nl_writer ns_new = {};
	+ int completed_len, new_len;
	+
	+ if (nw->enomem)
	+ return (false);
	+
	+ NL_LOG(LOG_DEBUG3, "no space at offset %d/%d (want %d), trying to reclaim",
	+ nw->offset, nw->alloc_len, required_len);
	+
	+ /* Calculated new buffer size and allocate it s*/
	+ completed_len = (nw->hdr != NULL) ? (char *)nw->hdr - nw->data : nw->offset;
	+ if (completed_len > 0 && required_len < MCLBYTES) {
	+ /* We already ran out of space, use the largest effective size */
	+ new_len = max(nw->alloc_len, MCLBYTES);
	+ } else {
	+ if (nw->alloc_len < MCLBYTES)
	+ new_len = MCLBYTES;
	+ else
	+ new_len = nw->alloc_len * 2;
	+ while (new_len < required_len)
	+ new_len *= 2;
	+ }
	+ bool waitok = (nw->malloc_flag == M_WAITOK);
	+ bool is_linux = (nw->writer_type == NS_WRITER_TYPE_LBUF);
	+ if (!nlmsg_get_buf(&ns_new, new_len, waitok, is_linux)) {
	+ nw->enomem = true;
	+ NL_LOG(LOG_DEBUG, "getting new buf failed, setting ENOMEM");
	+ return (false);
	+ }
	+ if (nw->ignore_limit)
	+ nlmsg_ignore_limit(&ns_new);
	+
	+ /* Update callback data */
	+ ns_new.writer_target = nw->writer_target;
	+ nlmsg_set_callback(&ns_new);
	+ ns_new.arg_uint = nw->arg_uint;
	+
	+ /* Copy last (unfinished) header to the new storage */
	+ int last_len = nw->offset - completed_len;
	+ if (last_len > 0) {
	+ memcpy(ns_new.data, nw->hdr, last_len);
	+ ns_new.hdr = (struct nlmsghdr *)ns_new.data;
	+ ns_new.offset = last_len;
	+ }
	+
	+ NL_LOG(LOG_DEBUG2, "completed: %d bytes, copied: %d bytes", completed_len, last_len);
	+
	+ /* Flush completed headers & switch to the new nw */
	+ nlmsg_flush(nw);
	+ memcpy(nw, &ns_new, sizeof(struct nl_writer));
	+ NL_LOG(LOG_DEBUG2, "switched buffer: used %d/%d bytes", nw->offset, nw->alloc_len);
	+
	+ return (true);
	+}
	+
	+bool
	+nlmsg_add(struct nl_writer *nw, uint32_t portid, uint32_t seq, uint16_t type,
	+ uint16_t flags, uint32_t len)
	+{
	+ struct nlmsghdr *hdr;
	+
	+ MPASS(nw->hdr == NULL);
	+
	+ int required_len = NETLINK_ALIGN(len + sizeof(struct nlmsghdr));
	+ if (__predict_false(nw->offset + required_len > nw->alloc_len)) {
	+ if (!nlmsg_refill_buffer(nw, required_len))
	+ return (false);
	+ }
	+
	+ hdr = (struct nlmsghdr *)(&nw->data[nw->offset]);
	+
	+ hdr->nlmsg_len = len;
	+ hdr->nlmsg_type = type;
	+ hdr->nlmsg_flags = flags;
	+ hdr->nlmsg_seq = seq;
	+ hdr->nlmsg_pid = portid;
	+
	+ nw->hdr = hdr;
	+ nw->offset += sizeof(struct nlmsghdr);
	+
	+ return (true);
	+}
	+
	+bool
	+nlmsg_end(struct nl_writer *nw)
	+{
	+ MPASS(nw->hdr != NULL);
	+
	+ if (nw->enomem) {
	+ NL_LOG(LOG_DEBUG, "ENOMEM when dumping message");
	+ nlmsg_abort(nw);
	+ return (false);
	+ }
	+
	+ nw->hdr->nlmsg_len = (uint32_t)(nw->data + nw->offset - (char *)nw->hdr);
	+ nw->hdr = NULL;
	+ nw->num_messages++;
	+ return (true);
	+}
	+
	+void
	+nlmsg_abort(struct nl_writer *nw)
	+{
	+ if (nw->hdr != NULL) {
	+ nw->offset = (uint32_t)((char *)nw->hdr - nw->data);
	+ nw->hdr = NULL;
	+ }
	+}
	+
	+void
	+nlmsg_ack(struct nlpcb nlp, int error, struct nlmsghdr hdr,
	+ struct nl_pstate *npt)
	+{
	+ struct nlmsgerr *errmsg;
	+ int payload_len;
	+ uint32_t flags = nlp->nl_flags;
	+ struct nl_writer *nw = npt->nw;
	+ bool cap_ack;
	+
	+ payload_len = sizeof(struct nlmsgerr);
	+
	+ /*
	+ * The only case when we send the full message in the
	+ * reply is when there is an error and NETLINK_CAP_ACK
	+ * is not set.
	+ */
	+ cap_ack = (error == 0) \|\| (flags & NLF_CAP_ACK);
	+ if (!cap_ack)
	+ payload_len += hdr->nlmsg_len - sizeof(struct nlmsghdr);
	+ payload_len = NETLINK_ALIGN(payload_len);
	+
	+ uint16_t nl_flags = cap_ack ? NLM_F_CAPPED : 0;
	+ if ((npt->err_msg \|\| npt->err_off) && nlp->nl_flags & NLF_EXT_ACK)
	+ nl_flags \|= NLM_F_ACK_TLVS;
	+
	+ /*
	+ * TODO: handle cookies
	+ */
	+
	+ NL_LOG(LOG_DEBUG3, "acknowledging message type %d seq %d",
	+ hdr->nlmsg_type, hdr->nlmsg_seq);
	+
	+ if (!nlmsg_add(nw, nlp->nl_port, hdr->nlmsg_seq, NLMSG_ERROR, nl_flags, payload_len))
	+ goto enomem;
	+
	+ errmsg = nlmsg_reserve_data(nw, payload_len, struct nlmsgerr);
	+ errmsg->error = error;
	+ /* In case of error copy the whole message, else just the header */
	+ memcpy(&errmsg->msg, hdr, cap_ack ? sizeof(*hdr) : hdr->nlmsg_len);
	+
	+ if (npt->err_msg != NULL && nlp->nl_flags & NLF_EXT_ACK)
	+ nlattr_add_string(nw, NLMSGERR_ATTR_MSG, npt->err_msg);
	+ if (npt->err_off != 0 && nlp->nl_flags & NLF_EXT_ACK)
	+ nlattr_add_u32(nw, NLMSGERR_ATTR_OFFS, npt->err_off);
	+
	+ if (nlmsg_end(nw))
	+ return;
	+enomem:
	+ NLP_LOG(LOG_DEBUG, nlp, "error allocating ack data for message %d seq %u",
	+ hdr->nlmsg_type, hdr->nlmsg_seq);
	+ nlmsg_abort(nw);
	+}
	+
	+bool
	+nlmsg_end_dump(struct nl_writer nw, int error, struct nlmsghdr hdr)
	+{
	+ if (!nlmsg_add(nw, hdr->nlmsg_pid, hdr->nlmsg_seq, NLMSG_DONE, 0, sizeof(int))) {
	+ NL_LOG(LOG_DEBUG, "Error finalizing table dump");
	+ return (false);
	+ }
	+ /* Save operation result */
	+ int *perror = nlmsg_reserve_object(nw, int);
	+ NL_LOG(LOG_DEBUG2, "record error=%d at off %d (%p)", error,
	+ nw->offset, perror);
	+ *perror = error;
	+ nlmsg_end(nw);
	+
	+ return (true);
	+}
	diff --git a/sys/netlink/netlink_module.c b/sys/netlink/netlink_module.c
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/netlink_module.c
	@@ -0,0 +1,228 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2021 Ng Peng Nam Sean
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+#include <sys/cdefs.h>
	+__FBSDID("$FreeBSD$");
	+#include <sys/param.h>
	+#include <sys/malloc.h>
	+#include <sys/module.h>
	+
	+#include <sys/lock.h>
	+#include <sys/rmlock.h>
	+#include <sys/ck.h>
	+#include <sys/syslog.h>
	+
	+#include <netlink/netlink.h>
	+#include <netlink/netlink_ctl.h>
	+#include <netlink/netlink_var.h>
	+
	+#include <machine/atomic.h>
	+
	+MALLOC_DEFINE(M_NETLINK, "netlink", "Memory used for netlink packets");
	+
	+#define DEBUG_MOD_NAME nl_mod
	+#define DEBUG_MAX_LEVEL LOG_DEBUG3
	+#include <netlink/netlink_debug.h>
	+_DECLARE_DEBUG(LOG_DEBUG);
	+
	+SYSCTL_NODE(_net, OID_AUTO, netlink, CTLFLAG_RD, 0, "");
	+SYSCTL_NODE(_net_netlink, OID_AUTO, debug, CTLFLAG_RD \| CTLFLAG_MPSAFE, 0, "");
	+
	+#define NL_MAX_HANDLERS 20
	+struct nl_proto_handler _nl_handlers[NL_MAX_HANDLERS];
	+struct nl_proto_handler *nl_handlers = _nl_handlers;
	+
	+CK_LIST_HEAD(nl_control_head, nl_control);
	+static struct nl_control_head vnets_head = CK_LIST_HEAD_INITIALIZER();
	+
	+VNET_DEFINE(struct nl_control *, nl_ctl) = NULL;
	+
	+struct mtx nl_global_mtx;
	+MTX_SYSINIT(nl_global_mtx, &nl_global_mtx, "global netlink lock", MTX_DEF);
	+
	+#define NL_GLOBAL_LOCK() mtx_lock(&nl_global_mtx)
	+#define NL_GLOBAL_UNLOCK() mtx_unlock(&nl_global_mtx)
	+
	+int netlink_unloading = 0;
	+
	+static void
	+free_nl_ctl(struct nl_control *ctl)
	+{
	+ rm_destroy(&ctl->ctl_lock);
	+ free(ctl, M_NETLINK);
	+}
	+
	+struct nl_control *
	+vnet_nl_ctl_init(void)
	+{
	+ struct nl_control *ctl;
	+
	+ ctl = malloc(sizeof(struct nl_control), M_NETLINK, M_WAITOK \| M_ZERO);
	+ rm_init(&ctl->ctl_lock, "netlink lock");
	+ CK_LIST_INIT(&ctl->ctl_port_head);
	+ CK_LIST_INIT(&ctl->ctl_pcb_head);
	+
	+ NL_GLOBAL_LOCK();
	+
	+ struct nl_control *tmp = atomic_load_ptr(&V_nl_ctl);
	+
	+ if (tmp == NULL) {
	+ atomic_store_ptr(&V_nl_ctl, ctl);
	+ CK_LIST_INSERT_HEAD(&vnets_head, ctl, ctl_next);
	+ NL_LOG(LOG_DEBUG2, "VNET %p init done, inserted %p into global list",
	+ curvnet, ctl);
	+ } else {
	+ NL_LOG(LOG_DEBUG, "per-VNET init clash, dropping this instance");
	+ free_nl_ctl(ctl);
	+ ctl = tmp;
	+ }
	+
	+ NL_GLOBAL_UNLOCK();
	+
	+ return (ctl);
	+}
	+
	+static void
	+vnet_nl_ctl_destroy(const void *unused __unused)
	+{
	+ struct nl_control *ctl;
	+
	+ /* Assume at the time all of the processes / sockets are dead */
	+
	+ NL_GLOBAL_LOCK();
	+ ctl = atomic_load_ptr(&V_nl_ctl);
	+ atomic_store_ptr(&V_nl_ctl, NULL);
	+ if (ctl != NULL) {
	+ NL_LOG(LOG_DEBUG2, "Removing %p from global list", ctl);
	+ CK_LIST_REMOVE(ctl, ctl_next);
	+ }
	+ NL_GLOBAL_UNLOCK();
	+
	+ if (ctl != NULL)
	+ free_nl_ctl(ctl);
	+}
	+VNET_SYSUNINIT(vnet_nl_ctl_destroy, SI_SUB_PROTO_IF, SI_ORDER_ANY,
	+ vnet_nl_ctl_destroy, NULL);
	+
	+int
	+nl_verify_proto(int proto)
	+{
	+ if (proto < 0 \|\| proto >= NL_MAX_HANDLERS) {
	+ return (EINVAL);
	+ }
	+ int handler_defined = nl_handlers[proto].cb != NULL;
	+ return (handler_defined ? 0 : EPROTONOSUPPORT);
	+}
	+
	+const char *
	+nl_get_proto_name(int proto)
	+{
	+ return (nl_handlers[proto].proto_name);
	+}
	+
	+bool
	+netlink_register_proto(int proto, const char *proto_name, nl_handler_f handler)
	+{
	+ if ((proto < 0) \|\| (proto >= NL_MAX_HANDLERS))
	+ return (false);
	+ NL_GLOBAL_LOCK();
	+ KASSERT((nl_handlers[proto].cb == NULL), ("netlink handler %d is already set", proto));
	+ nl_handlers[proto].cb = handler;
	+ nl_handlers[proto].proto_name = proto_name;
	+ NL_GLOBAL_UNLOCK();
	+ NL_LOG(LOG_DEBUG, "Registered netlink %s(%d) handler", proto_name, proto);
	+ return (true);
	+}
	+
	+bool
	+netlink_unregister_proto(int proto)
	+{
	+ if ((proto < 0) \|\| (proto >= NL_MAX_HANDLERS))
	+ return (false);
	+ NL_GLOBAL_LOCK();
	+ KASSERT((nl_handlers[proto].cb != NULL), ("netlink handler %d is not set", proto));
	+ nl_handlers[proto].cb = NULL;
	+ nl_handlers[proto].proto_name = NULL;
	+ NL_GLOBAL_UNLOCK();
	+ NL_LOG(LOG_DEBUG, "Unregistered netlink proto %d handler", proto);
	+ return (true);
	+}
	+
	+static bool
	+can_unload(void)
	+{
	+ struct nl_control *ctl;
	+ bool result = true;
	+
	+ NL_GLOBAL_LOCK();
	+
	+ CK_LIST_FOREACH(ctl, &vnets_head, ctl_next) {
	+ NL_LOG(LOG_DEBUG2, "Iterating VNET head %p", ctl);
	+ if (!CK_LIST_EMPTY(&ctl->ctl_pcb_head)) {
	+ NL_LOG(LOG_NOTICE, "non-empty socket list in ctl %p", ctl);
	+ result = false;
	+ break;
	+ }
	+ }
	+
	+ NL_GLOBAL_UNLOCK();
	+
	+ return (result);
	+}
	+
	+static int
	+netlink_modevent(module_t mod __unused, int what, void *priv __unused)
	+{
	+ int ret = 0;
	+
	+ switch (what) {
	+ case MOD_LOAD:
	+ NL_LOG(LOG_DEBUG, "Loading");
	+ NL_LOG(LOG_NOTICE, "netlink support is in BETA stage");
	+ break;
	+
	+ case MOD_UNLOAD:
	+ NL_LOG(LOG_DEBUG, "Unload called");
	+ if (can_unload()) {
	+ NL_LOG(LOG_WARNING, "unloading");
	+ netlink_unloading = 1;
	+ } else
	+ ret = EBUSY;
	+ break;
	+
	+ default:
	+ ret = EOPNOTSUPP;
	+ break;
	+ }
	+
	+ return (ret);
	+}
	+static moduledata_t netlink_mod = { "netlink", netlink_modevent, NULL };
	+
	+DECLARE_MODULE(netlink, netlink_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
	+MODULE_VERSION(netlink, 1);
	diff --git a/sys/netlink/netlink_route.h b/sys/netlink/netlink_route.h
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/netlink_route.h
	@@ -0,0 +1,43 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+#ifndef _NETLINK_NETLINK_ROUTE_H_
	+#define _NETLINK_NETLINK_ROUTE_H_
	+
	+#include <sys/types.h>
	+
	+#include <net/if.h>
	+#include <net/if_types.h>
	+#include <net/if_var.h>
	+
	+#include <netlink/route/common.h>
	+#include <netlink/route/ifaddrs.h>
	+#include <netlink/route/interface.h>
	+#include <netlink/route/neigh.h>
	+#include <netlink/route/route.h>
	+#include <netlink/route/nexthop.h>
	+
	+#endif
	diff --git a/sys/netlink/netlink_route.c b/sys/netlink/netlink_route.c
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/netlink_route.c
	@@ -0,0 +1,135 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+#include <sys/cdefs.h>
	+__FBSDID("$FreeBSD$");
	+#include <sys/types.h>
	+#include <sys/malloc.h>
	+#include <sys/socket.h>
	+#include <sys/ck.h>
	+
	+#include <net/route.h>
	+#include <net/route/route_ctl.h>
	+#include <netlink/netlink.h>
	+#include <netlink/netlink_ctl.h>
	+#include <netlink/netlink_var.h>
	+#include <netlink/netlink_route.h>
	+#include <netlink/route/route_var.h>
	+
	+#define DEBUG_MOD_NAME nl_route_core
	+#define DEBUG_MAX_LEVEL LOG_DEBUG3
	+#include <netlink/netlink_debug.h>
	+_DECLARE_DEBUG(LOG_DEBUG);
	+
	+#define HANDLER_MAX_NUM (NL_RTM_MAX + 10)
	+static const struct rtnl_cmd_handler *rtnl_handler[HANDLER_MAX_NUM] = {};
	+
	+bool
	+rtnl_register_messages(const struct rtnl_cmd_handler *handlers, int count)
	+{
	+ for (int i = 0; i < count; i++) {
	+ if (handlers[i].cmd >= HANDLER_MAX_NUM)
	+ return (false);
	+ MPASS(rtnl_handler[handlers[i].cmd] == NULL);
	+ }
	+ for (int i = 0; i < count; i++)
	+ rtnl_handler[handlers[i].cmd] = &handlers[i];
	+ return (true);
	+}
	+
	+/*
	+ * Handler called by netlink subsystem when matching netlink message is received
	+ */
	+static int
	+rtnl_handle_message(struct nlmsghdr hdr, struct nl_pstate npt)
	+{
	+ const struct rtnl_cmd_handler *cmd;
	+ struct epoch_tracker et;
	+ struct nlpcb *nlp = npt->nlp;
	+ int error = 0;
	+
	+ if (__predict_false(hdr->nlmsg_type >= HANDLER_MAX_NUM)) {
	+ NLMSG_REPORT_ERR_MSG(npt, "unknown message type: %d", hdr->nlmsg_type);
	+ return (ENOTSUP);
	+ }
	+
	+ cmd = rtnl_handler[hdr->nlmsg_type];
	+ if (__predict_false(cmd == NULL)) {
	+ NLMSG_REPORT_ERR_MSG(npt, "unknown message type: %d", hdr->nlmsg_type);
	+ return (ENOTSUP);
	+ }
	+
	+ NLP_LOG(LOG_DEBUG2, nlp, "received msg %s(%d) len %d", cmd->name,
	+ hdr->nlmsg_type, hdr->nlmsg_len);
	+
	+ if (cmd->priv != 0 && !nlp_has_priv(nlp, cmd->priv)) {
	+ NLP_LOG(LOG_DEBUG2, nlp, "priv %d check failed for msg %s", cmd->priv, cmd->name);
	+ return (EPERM);
	+ } else if (cmd->priv != 0)
	+ NLP_LOG(LOG_DEBUG3, nlp, "priv %d check passed for msg %s", cmd->priv, cmd->name);
	+
	+ bool need_epoch = !(cmd->flags & RTNL_F_NOEPOCH);
	+
	+ if (need_epoch)
	+ NET_EPOCH_ENTER(et);
	+ error = cmd->cb(hdr, nlp, npt);
	+ if (need_epoch)
	+ NET_EPOCH_EXIT(et);
	+
	+ NLP_LOG(LOG_DEBUG3, nlp, "message %s -> error %d", cmd->name, error);
	+
	+ return (error);
	+}
	+
	+static struct rtbridge nlbridge = { .route_f = rtnl_handle_route_event };
	+static struct rtbridge *nlbridge_orig_p;
	+
	+static void
	+rtnl_load(void *u __unused)
	+{
	+ NL_LOG(LOG_NOTICE, "rtnl loading");
	+ nlbridge_orig_p = netlink_callback_p;
	+ netlink_callback_p = &nlbridge;
	+ rtnl_neighs_init();
	+ rtnl_ifaces_init();
	+ rtnl_nexthops_init();
	+ rtnl_routes_init();
	+ netlink_register_proto(NETLINK_ROUTE, "NETLINK_ROUTE", rtnl_handle_message);
	+}
	+SYSINIT(rtnl_load, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, rtnl_load, NULL);
	+
	+static void
	+rtnl_unload(void *u __unused)
	+{
	+ netlink_callback_p = nlbridge_orig_p;
	+ rtnl_ifaces_destroy();
	+ rtnl_neighs_destroy();
	+
	+ /* Wait till all consumers read nlbridge data */
	+ epoch_wait_preempt(net_epoch_preempt);
	+}
	+SYSUNINIT(rtnl_unload, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, rtnl_unload, NULL);
	diff --git a/sys/netlink/netlink_var.h b/sys/netlink/netlink_var.h
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/netlink_var.h
	@@ -0,0 +1,142 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2021 Ng Peng Nam Sean
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+#ifndef _NETLINK_NETLINK_VAR_H_
	+#define _NETLINK_NETLINK_VAR_H_
	+
	+#include <sys/ck.h>
	+#include <sys/epoch.h>
	+#include <sys/sysctl.h>
	+#include <sys/taskqueue.h>
	+#include <net/vnet.h>
	+
	+#define NLSNDQ 65536 /* Default socket sendspace */
	+#define NLRCVQ 65536 /* Default socket recvspace */
	+
	+struct ucred;
	+
	+struct nl_io_queue {
	+ STAILQ_HEAD(, mbuf) head;
	+ int length;
	+ int hiwat;
	+};
	+
	+struct nlpcb {
	+ struct socket *nl_socket;
	+ uint64_t nl_groups;
	+ uint32_t nl_port;
	+ uint32_t nl_flags;
	+ uint32_t nl_process_id;
	+ int nl_proto;
	+ bool nl_active;
	+ bool nl_bound;
	+ bool nl_task_pending;
	+ bool nl_tx_blocked; /* No new requests accepted */
	+ bool nl_linux; /* true if running under compat */
	+ struct nl_io_queue rx_queue;
	+ struct nl_io_queue tx_queue;
	+ struct taskqueue *nl_taskqueue;
	+ struct task nl_task;
	+ struct ucred nl_cred; / Copy of nl_socket->so_cred */
	+ uint64_t nl_dropped_bytes;
	+ uint64_t nl_dropped_messages;
	+ CK_LIST_ENTRY(nlpcb) nl_next;
	+ CK_LIST_ENTRY(nlpcb) nl_port_next;
	+ volatile u_int nl_refcount;
	+ struct mtx nl_lock;
	+ struct epoch_context nl_epoch_ctx;
	+};
	+#define sotonlpcb(so) ((struct nlpcb *)(so)->so_pcb)
	+
	+#define NLP_LOCK_INIT(_nlp) mtx_init(&((_nlp)->nl_lock), "nlp mtx", NULL, MTX_DEF)
	+#define NLP_LOCK_DESTROY(_nlp) mtx_destroy(&((_nlp)->nl_lock))
	+#define NLP_LOCK(_nlp) mtx_lock(&((_nlp)->nl_lock))
	+#define NLP_UNLOCK(_nlp) mtx_unlock(&((_nlp)->nl_lock))
	+
	+#define ALIGNED_NL_SZ(_data) roundup2((((struct nlmsghdr *)(_data))->nlmsg_len), 16)
	+
	+/* nl_flags */
	+#define NLF_CAP_ACK 0x01 /* Do not send message body with errmsg */
	+#define NLF_EXT_ACK 0x02 /* Allow including extended TLVs in ack */
	+#define NLF_STRICT 0x04 /* Perform strict header checks */
	+
	+SYSCTL_DECL(_net_netlink);
	+
	+struct nl_io {
	+ struct callout callout;
	+ struct mbuf *head;
	+ struct mbuf *last;
	+ int64_t length;
	+};
	+
	+struct nl_control {
	+ CK_LIST_HEAD(nl_pid_head, nlpcb) ctl_port_head;
	+ CK_LIST_HEAD(nlpcb_head, nlpcb) ctl_pcb_head;
	+ CK_LIST_ENTRY(nl_control) ctl_next;
	+ struct nl_io ctl_io;
	+ struct rmlock ctl_lock;
	+};
	+VNET_DECLARE(struct nl_control *, nl_ctl);
	+#define V_nl_ctl VNET(nl_ctl)
	+
	+
	+struct sockaddr_nl;
	+struct sockaddr;
	+struct nlmsghdr;
	+
	+/* netlink_module.c */
	+struct nl_control *vnet_nl_ctl_init(void);
	+
	+int nl_verify_proto(int proto);
	+const char *nl_get_proto_name(int proto);
	+
	+extern int netlink_unloading;
	+
	+struct nl_proto_handler {
	+ nl_handler_f cb;
	+ const char *proto_name;
	+};
	+extern struct nl_proto_handler *nl_handlers;
	+
	+/* netlink_domain.c */
	+void nl_send_group(struct mbuf *m, int cnt, int proto, int group_id);
	+
	+/* netlink_io.c */
	+#define NL_IOF_UNTRANSLATED 0x01
	+#define NL_IOF_IGNORE_LIMIT 0x02
	+bool nl_send_one(struct mbuf m, struct nlpcb nlp, int cnt, int io_flags);
	+void nlmsg_ack(struct nlpcb nlp, int error, struct nlmsghdr nlmsg,
	+ struct nl_pstate *npt);
	+void nl_on_transmit(struct nlpcb *nlp);
	+void nl_init_io(struct nlpcb *nlp);
	+void nl_free_io(struct nlpcb *nlp);
	+
	+void nl_taskqueue_handler(void *_arg, int pending);
	+int nl_receive_async(struct mbuf m, struct socket so);
	+void nl_process_receive_locked(struct nlpcb *nlp);
	+
	+#endif
	diff --git a/sys/netlink/route/common.h b/sys/netlink/route/common.h
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/route/common.h
	@@ -0,0 +1,213 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+/*
	+ * Common defines for all parts of the NETLINK_ROUTE family
	+ */
	+#ifndef _NETLINK_ROUTE_COMMON_H_
	+#define _NETLINK_ROUTE_COMMON_H_
	+
	+/* Defined NETLINK_ROUTE messages */
	+enum {
	+ NL_RTM_BASE = 16,
	+ NL_RTM_NEWLINK = 16, /* creates new interface */
	+ NL_RTM_DELLINK = 17, /* deletes matching interface */
	+ NL_RTM_GETLINK = 18, /* lists matching interfaces */
	+ NL_RTM_SETLINK = 19, /* not supported */
	+ NL_RTM_NEWADDR = 20, /* not supported */
	+ NL_RTM_DELADDR = 21, /* not supported */
	+ NL_RTM_GETADDR = 22, /* lists matching ifaddrs */
	+ NL_RTM_NEWROUTE = 24, /* adds or changes a route */
	+ NL_RTM_DELROUTE = 25, /* deletes matching route */
	+ NL_RTM_GETROUTE = 26, /* lists matching routes */
	+ NL_RTM_NEWNEIGH = 28, /* creates new arp/ndp entry */
	+ NL_RTM_DELNEIGH = 29, /* deletes matching arp/ndp entry */
	+ NL_RTM_GETNEIGH = 30, /* lists matching arp/ndp entry */
	+ NL_RTM_NEWRULE = 32, /* not supported */
	+ NL_RTM_DELRULE = 33, /* not supported */
	+ NL_RTM_GETRULE = 34, /* not supported */
	+ NL_RTM_NEWQDISC = 36, /* not supported */
	+ NL_RTM_DELQDISC = 37, /* not supported */
	+ NL_RTM_GETQDISC = 38, /* not supported */
	+ NL_RTM_NEWTCLASS = 40, /* not supported */
	+ NL_RTM_DELTCLASS = 41, /* not supported */
	+ NL_RTM_GETTCLASS = 42, /* not supported */
	+ NL_RTM_NEWTFILTER = 44, /* not supported */
	+ NL_RTM_DELTFILTER = 45, /* not supported */
	+ NL_RTM_GETTFILTER = 46, /* not supported */
	+ NL_RTM_NEWACTION = 48, /* not supported */
	+ NL_RTM_DELACTION = 49, /* not supported */
	+ NL_RTM_GETACTION = 50, /* not supported */
	+ NL_RTM_NEWPREFIX = 52, /* not supported */
	+ NL_RTM_GETMULTICAST = 58, /* not supported */
	+ NL_RTM_GETANYCAST = 62, /* not supported */
	+ NL_RTM_NEWNEIGHTBL = 64, /* not supported */
	+ NL_RTM_GETNEIGHTBL = 66, /* not supported */
	+ NL_RTM_SETNEIGHTBL = 67, /* not supported */
	+ NL_RTM_NEWNDUSEROPT = 68, /* not supported */
	+ NL_RTM_NEWADDRLABEL = 72, /* not supported */
	+ NL_RTM_DELADDRLABEL = 73, /* not supported */
	+ NL_RTM_GETADDRLABEL = 74, /* not supported */
	+ NL_RTM_GETDCB = 78, /* not supported */
	+ NL_RTM_SETDCB = 79, /* not supported */
	+ NL_RTM_NEWNETCONF = 80, /* not supported */
	+ NL_RTM_GETNETCONF = 82, /* not supported */
	+ NL_RTM_NEWMDB = 84, /* not supported */
	+ NL_RTM_DELMDB = 85, /* not supported */
	+ NL_RTM_GETMDB = 86, /* not supported */
	+ NL_RTM_NEWNSID = 88, /* not supported */
	+ NL_RTM_DELNSID = 89, /* not supported */
	+ NL_RTM_GETNSID = 90, /* not supported */
	+ NL_RTM_NEWSTATS = 92, /* not supported */
	+ NL_RTM_GETSTATS = 94, /* not supported */
	+ NL_RTM_NEWNEXTHOP = 104, /* creates new user nexhtop */
	+ NL_RTM_DELNEXTHOP = 105, /* deletes matching nexthop */
	+ NL_RTM_GETNEXTHOP = 106, /* lists created user nexthops */
	+ __NL_RTM_MAX,
	+};
	+#define NL_RTM_MAX (((__NL_RTM_MAX + 3) & ~3) - 1)
	+
	+#ifndef _KERNEL
	+/*
	+ * RTM_* namespace clashes with BSD rtsock namespace.
	+ * Use NL_RTM_ prefix in the kernel and map it to RTM_
	+ * for userland.
	+ */
	+#define RTM_BASE NL_RTM_BASE
	+#define RTM_NEWLINK NL_RTM_NEWLINK
	+#define RTM_DELLINK NL_RTM_DELLINK
	+#define RTM_GETLINK NL_RTM_GETLINK
	+#define RTM_SETLINK NL_RTM_SETLINK
	+#define RTM_NEWADDR NL_RTM_NEWADDR
	+#define RTM_DELADDR NL_RTM_DELADDR
	+#define RTM_GETADDR NL_RTM_GETADDR
	+#define RTM_NEWROUTE NL_RTM_NEWROUTE
	+#define RTM_DELROUTE NL_RTM_DELROUTE
	+#define RTM_GETROUTE NL_RTM_GETROUTE
	+#define RTM_NEWNEXTHOP NL_RTM_NEWNEXTHOP
	+#define RTM_DELNEXTHOP NL_RTM_DELNEXTHOP
	+#define RTM_GETNEXTHOP NL_RTM_GETNEXTHOP
	+#endif
	+
	+#ifndef _KERNEL
	+/* rtnetlink multicast groups - backwards compatibility for userspace */
	+#define RTMGRP_LINK 0x01
	+#define RTMGRP_NOTIFY 0x02
	+#define RTMGRP_NEIGH 0x04
	+#define RTMGRP_TC 0x08
	+
	+#define RTMGRP_IPV4_IFADDR 0x10
	+#define RTMGRP_IPV4_MROUTE 0x20
	+#define RTMGRP_IPV4_ROUTE 0x40
	+#define RTMGRP_IPV4_RULE 0x80
	+
	+#define RTMGRP_IPV6_IFADDR 0x100
	+#define RTMGRP_IPV6_MROUTE 0x200
	+#define RTMGRP_IPV6_ROUTE 0x400
	+#define RTMGRP_IPV6_IFINFO 0x800
	+
	+#define RTMGRP_DECnet_IFADDR 0x1000
	+#define RTMGRP_DECnet_ROUTE 0x4000
	+
	+#define RTMGRP_IPV6_PREFIX 0x20000
	+#endif
	+
	+/* Defined NETLINK_ROUTE multicast groups */
	+enum rtnetlink_groups {
	+ RTNLGRP_NONE,
	+#define RTNLGRP_NONE RTNLGRP_NONE
	+ RTNLGRP_LINK,
	+#define RTNLGRP_LINK RTNLGRP_LINK
	+ RTNLGRP_NOTIFY,
	+#define RTNLGRP_NOTIFY RTNLGRP_NOTIFY
	+ RTNLGRP_NEIGH,
	+#define RTNLGRP_NEIGH RTNLGRP_NEIGH
	+ RTNLGRP_TC,
	+#define RTNLGRP_TC RTNLGRP_TC
	+ RTNLGRP_IPV4_IFADDR,
	+#define RTNLGRP_IPV4_IFADDR RTNLGRP_IPV4_IFADDR
	+ RTNLGRP_IPV4_MROUTE,
	+#define RTNLGRP_IPV4_MROUTE RTNLGRP_IPV4_MROUTE
	+ RTNLGRP_IPV4_ROUTE,
	+#define RTNLGRP_IPV4_ROUTE RTNLGRP_IPV4_ROUTE
	+ RTNLGRP_IPV4_RULE,
	+#define RTNLGRP_IPV4_RULE RTNLGRP_IPV4_RULE
	+ RTNLGRP_IPV6_IFADDR,
	+#define RTNLGRP_IPV6_IFADDR RTNLGRP_IPV6_IFADDR
	+ RTNLGRP_IPV6_MROUTE,
	+#define RTNLGRP_IPV6_MROUTE RTNLGRP_IPV6_MROUTE
	+ RTNLGRP_IPV6_ROUTE,
	+#define RTNLGRP_IPV6_ROUTE RTNLGRP_IPV6_ROUTE
	+ RTNLGRP_IPV6_IFINFO,
	+#define RTNLGRP_IPV6_IFINFO RTNLGRP_IPV6_IFINFO
	+ RTNLGRP_DECnet_IFADDR,
	+#define RTNLGRP_DECnet_IFADDR RTNLGRP_DECnet_IFADDR
	+ RTNLGRP_NOP2,
	+ RTNLGRP_DECnet_ROUTE,
	+#define RTNLGRP_DECnet_ROUTE RTNLGRP_DECnet_ROUTE
	+ RTNLGRP_DECnet_RULE,
	+#define RTNLGRP_DECnet_RULE RTNLGRP_DECnet_RULE
	+ RTNLGRP_NOP4,
	+ RTNLGRP_IPV6_PREFIX,
	+#define RTNLGRP_IPV6_PREFIX RTNLGRP_IPV6_PREFIX
	+ RTNLGRP_IPV6_RULE,
	+#define RTNLGRP_IPV6_RULE RTNLGRP_IPV6_RULE
	+ RTNLGRP_ND_USEROPT,
	+#define RTNLGRP_ND_USEROPT RTNLGRP_ND_USEROPT
	+ RTNLGRP_PHONET_IFADDR,
	+#define RTNLGRP_PHONET_IFADDR RTNLGRP_PHONET_IFADDR
	+ RTNLGRP_PHONET_ROUTE,
	+#define RTNLGRP_PHONET_ROUTE RTNLGRP_PHONET_ROUTE
	+ RTNLGRP_DCB,
	+#define RTNLGRP_DCB RTNLGRP_DCB
	+ RTNLGRP_IPV4_NETCONF,
	+#define RTNLGRP_IPV4_NETCONF RTNLGRP_IPV4_NETCONF
	+ RTNLGRP_IPV6_NETCONF,
	+#define RTNLGRP_IPV6_NETCONF RTNLGRP_IPV6_NETCONF
	+ RTNLGRP_MDB,
	+#define RTNLGRP_MDB RTNLGRP_MDB
	+ RTNLGRP_MPLS_ROUTE,
	+#define RTNLGRP_MPLS_ROUTE RTNLGRP_MPLS_ROUTE
	+ RTNLGRP_NSID,
	+#define RTNLGRP_NSID RTNLGRP_NSID
	+ RTNLGRP_MPLS_NETCONF,
	+#define RTNLGRP_MPLS_NETCONF RTNLGRP_MPLS_NETCONF
	+ RTNLGRP_IPV4_MROUTE_R,
	+#define RTNLGRP_IPV4_MROUTE_R RTNLGRP_IPV4_MROUTE_R
	+ RTNLGRP_IPV6_MROUTE_R,
	+#define RTNLGRP_IPV6_MROUTE_R RTNLGRP_IPV6_MROUTE_R
	+ RTNLGRP_NEXTHOP,
	+#define RTNLGRP_NEXTHOP RTNLGRP_NEXTHOP
	+ RTNLGRP_BRVLAN,
	+#define RTNLGRP_BRVLAN RTNLGRP_BRVLAN
	+ __RTNLGRP_MAX
	+};
	+#define RTNLGRP_MAX (__RTNLGRP_MAX - 1)
	+
	+
	+#endif
	+
	diff --git a/sys/netlink/route/iface.c b/sys/netlink/route/iface.c
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/route/iface.c
	@@ -0,0 +1,857 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+#include <sys/cdefs.h>
	+__FBSDID("$FreeBSD$");
	+#include "opt_inet.h"
	+#include "opt_inet6.h"
	+#include <sys/types.h>
	+#include <sys/malloc.h>
	+#include <sys/socket.h>
	+#include <sys/sockio.h>
	+#include <sys/syslog.h>
	+
	+#include <net/if.h>
	+#include <net/if_dl.h>
	+#include <net/if_media.h>
	+#include <net/if_var.h>
	+#include <net/if_clone.h>
	+#include <net/route.h>
	+#include <net/route/nhop.h>
	+#include <net/route/route_ctl.h>
	+#include <netlink/netlink.h>
	+#include <netlink/netlink_ctl.h>
	+#include <netlink/netlink_route.h>
	+#include <netlink/route/route_var.h>
	+
	+#include <netinet6/scope6_var.h> /* scope deembedding */
	+
	+#define DEBUG_MOD_NAME nl_iface
	+#define DEBUG_MAX_LEVEL LOG_DEBUG3
	+#include <netlink/netlink_debug.h>
	+_DECLARE_DEBUG(LOG_DEBUG);
	+
	+struct netlink_walkargs {
	+ struct nl_writer *nw;
	+ struct nlmsghdr hdr;
	+ struct nlpcb *so;
	+ uint32_t fibnum;
	+ int family;
	+ int error;
	+ int count;
	+ int dumped;
	+};
	+
	+static eventhandler_tag ifdetach_event, ifattach_event, ifaddr_event;
	+
	+static SLIST_HEAD(, nl_cloner) nl_cloners = SLIST_HEAD_INITIALIZER(nl_cloners);
	+
	+static struct sx rtnl_cloner_lock;
	+SX_SYSINIT(rtnl_cloner_lock, &rtnl_cloner_lock, "rtnl cloner lock");
	+
	+/*
	+ * RTM_GETLINK request
	+ * sendto(3, {{len=32, type=RTM_GETLINK, flags=NLM_F_REQUEST\|NLM_F_DUMP, seq=1641940952, pid=0},
	+ * {ifi_family=AF_INET, ifi_type=ARPHRD_NETROM, ifi_index=0, ifi_flags=0, ifi_change=0}}, 32, 0, NULL, 0) = 32
	+ *
	+ * Reply:
	+ * {ifi_family=AF_UNSPEC, ifi_type=ARPHRD_ETHER, ifi_index=if_nametoindex("enp0s31f6"), ifi_flags=IFF_UP\|IFF_BROADCAST\|IFF_RUNNING\|IFF_MULTICAST\|IFF_LOWER_UP, ifi_change=0},
	+{{nla_len=10, nla_type=IFLA_ADDRESS}, "\xfe\x54\x00\x52\x3e\x90"}
	+
	+[
	+{{nla_len=14, nla_type=IFLA_IFNAME}, "enp0s31f6"},
	+{{nla_len=8, nla_type=IFLA_TXQLEN}, 1000},
	+{{nla_len=5, nla_type=IFLA_OPERSTATE}, 6},
	+{{nla_len=5, nla_type=IFLA_LINKMODE}, 0},
	+{{nla_len=8, nla_type=IFLA_MTU}, 1500},
	+{{nla_len=8, nla_type=IFLA_MIN_MTU}, 68},
	+ {{nla_len=8, nla_type=IFLA_MAX_MTU}, 9000},
	+{{nla_len=8, nla_type=IFLA_GROUP}, 0},
	+{{nla_len=8, nla_type=IFLA_PROMISCUITY}, 0},
	+{{nla_len=8, nla_type=IFLA_NUM_TX_QUEUES}, 1},
	+{{nla_len=8, nla_type=IFLA_GSO_MAX_SEGS}, 65535},
	+{{nla_len=8, nla_type=IFLA_GSO_MAX_SIZE}, 65536},
	+{{nla_len=8, nla_type=IFLA_NUM_RX_QUEUES}, 1},
	+{{nla_len=5, nla_type=IFLA_CARRIER}, 1},
	+{{nla_len=13, nla_type=IFLA_QDISC}, "fq_codel"},
	+{{nla_len=8, nla_type=IFLA_CARRIER_CHANGES}, 2},
	+{{nla_len=5, nla_type=IFLA_PROTO_DOWN}, 0},
	+{{nla_len=8, nla_type=IFLA_CARRIER_UP_COUNT}, 1},
	+{{nla_len=8, nla_type=IFLA_CARRIER_DOWN_COUNT}, 1},
	+ */
	+
	+struct if_state {
	+ uint8_t ifla_operstate;
	+ uint8_t ifla_carrier;
	+};
	+
	+static void
	+get_operstate_ether(struct ifnet ifp, struct if_state pstate)
	+{
	+ struct ifmediareq ifmr = {};
	+ int error;
	+ error = (ifp->if_ioctl)(ifp, SIOCGIFMEDIA, (void )&ifmr);
	+
	+ if (error != 0) {
	+ NL_LOG(LOG_DEBUG, "error calling SIOCGIFMEDIA on %s: %d",
	+ if_name(ifp), error);
	+ return;
	+ }
	+
	+ switch (IFM_TYPE(ifmr.ifm_active)) {
	+ case IFM_ETHER:
	+ if (ifmr.ifm_status & IFM_ACTIVE) {
	+ pstate->ifla_carrier = 1;
	+ if (ifp->if_flags & IFF_MONITOR)
	+ pstate->ifla_operstate = IF_OPER_DORMANT;
	+ else
	+ pstate->ifla_operstate = IF_OPER_UP;
	+ } else
	+ pstate->ifla_operstate = IF_OPER_DOWN;
	+ }
	+}
	+
	+static bool
	+get_stats(struct nl_writer nw, struct ifnet ifp)
	+{
	+ struct rtnl_link_stats64 *stats;
	+
	+ int nla_len = sizeof(struct nlattr) + sizeof(*stats);
	+ struct nlattr *nla = nlmsg_reserve_data(nw, nla_len, struct nlattr);
	+ if (nla == NULL)
	+ return (false);
	+ nla->nla_type = IFLA_STATS64;
	+ nla->nla_len = nla_len;
	+ stats = (struct rtnl_link_stats64 *)(nla + 1);
	+
	+ stats->rx_packets = ifp->if_get_counter(ifp, IFCOUNTER_IPACKETS);
	+ stats->tx_packets = ifp->if_get_counter(ifp, IFCOUNTER_OPACKETS);
	+ stats->rx_bytes = ifp->if_get_counter(ifp, IFCOUNTER_IBYTES);
	+ stats->tx_bytes = ifp->if_get_counter(ifp, IFCOUNTER_OBYTES);
	+ stats->rx_errors = ifp->if_get_counter(ifp, IFCOUNTER_IERRORS);
	+ stats->tx_errors = ifp->if_get_counter(ifp, IFCOUNTER_OERRORS);
	+ stats->rx_dropped = ifp->if_get_counter(ifp, IFCOUNTER_IQDROPS);
	+ stats->tx_dropped = ifp->if_get_counter(ifp, IFCOUNTER_OQDROPS);
	+ stats->multicast = ifp->if_get_counter(ifp, IFCOUNTER_IMCASTS);
	+ stats->rx_nohandler = ifp->if_get_counter(ifp, IFCOUNTER_NOPROTO);
	+
	+ return (true);
	+}
	+
	+static void
	+get_operstate(struct ifnet ifp, struct if_state pstate)
	+{
	+ pstate->ifla_operstate = IF_OPER_UNKNOWN;
	+ pstate->ifla_carrier = 0; /* no carrier */
	+
	+ switch (ifp->if_type) {
	+ case IFT_ETHER:
	+ get_operstate_ether(ifp, pstate);
	+ break;
	+ case IFT_LOOP:
	+ if (ifp->if_flags & IFF_UP) {
	+ pstate->ifla_operstate = IF_OPER_UP;
	+ pstate->ifla_carrier = 1;
	+ } else
	+ pstate->ifla_operstate = IF_OPER_DOWN;
	+ break;
	+ }
	+}
	+
	+static unsigned
	+ifp_flags_to_netlink(const struct ifnet *ifp)
	+{
	+ return (ifp->if_flags \| ifp->if_drv_flags);
	+}
	+
	+#define LLADDR_CONST(s) ((const void *)((s)->sdl_data + (s)->sdl_nlen))
	+static bool
	+dump_sa(struct nl_writer nw, int attr, const struct sockaddr sa)
	+{
	+ uint32_t addr_len = 0;
	+ const void *addr_data = NULL;
	+ struct in6_addr addr6;
	+
	+ if (sa == NULL)
	+ return (true);
	+
	+ switch (sa->sa_family) {
	+ case AF_INET:
	+ addr_len = sizeof(struct in_addr);
	+ addr_data = &((const struct sockaddr_in *)sa)->sin_addr;
	+ break;
	+ case AF_INET6:
	+ in6_splitscope(&((const struct sockaddr_in6 *)sa)->sin6_addr, &addr6, &addr_len);
	+ addr_len = sizeof(struct in6_addr);
	+ addr_data = &addr6;
	+ break;
	+ case AF_LINK:
	+ addr_len = ((const struct sockaddr_dl *)sa)->sdl_alen;
	+ addr_data = LLADDR_CONST((const struct sockaddr_dl *)sa);
	+ break;
	+ default:
	+ NL_LOG(LOG_DEBUG, "unsupported family: %d, skipping", sa->sa_family);
	+ return (true);
	+ }
	+
	+ return (nlattr_add(nw, attr, addr_len, addr_data));
	+}
	+
	+/*
	+ * Dumps interface state, properties and metrics.
	+ * @nw: message writer
	+ * @ifp: target interface
	+ * @hdr: template header
	+ *
	+ * This function is called without epoch and MAY sleep.
	+ */
	+static bool
	+dump_iface(struct nl_writer nw, struct ifnet ifp, const struct nlmsghdr *hdr)
	+{
	+ struct ifinfomsg *ifinfo;
	+
	+ NL_LOG(LOG_DEBUG3, "dumping interface %s data", if_name(ifp));
	+
	+ if (!nlmsg_reply(nw, hdr, sizeof(struct ifinfomsg)))
	+ goto enomem;
	+
	+ ifinfo = nlmsg_reserve_object(nw, struct ifinfomsg);
	+ ifinfo->ifi_family = AF_UNSPEC;
	+ ifinfo->__ifi_pad = 0;
	+ ifinfo->ifi_type = ifp->if_type;
	+ ifinfo->ifi_index = ifp->if_index;
	+ ifinfo->ifi_flags = ifp_flags_to_netlink(ifp);
	+ ifinfo->ifi_change = 0;
	+
	+ nlattr_add_string(nw, IFLA_IFNAME, if_name(ifp));
	+
	+ struct if_state ifs = {};
	+ get_operstate(ifp, &ifs);
	+
	+ nlattr_add_u8(nw, IFLA_OPERSTATE, ifs.ifla_operstate);
	+ nlattr_add_u8(nw, IFLA_CARRIER, ifs.ifla_carrier);
	+
	+/*
	+ nlattr_add_u8(nw, IFLA_PROTO_DOWN, val);
	+ nlattr_add_u8(nw, IFLA_LINKMODE, val);
	+*/
	+ if ((ifp->if_addr != NULL)) {
	+ dump_sa(nw, IFLA_ADDRESS, ifp->if_addr->ifa_addr);
	+ }
	+
	+ if ((ifp->if_broadcastaddr != NULL)) {
	+ nlattr_add(nw, IFLA_BROADCAST, ifp->if_addrlen,
	+ ifp->if_broadcastaddr);
	+ }
	+
	+ nlattr_add_u32(nw, IFLA_MTU, ifp->if_mtu);
	+/*
	+ nlattr_add_u32(nw, IFLA_MIN_MTU, 60);
	+ nlattr_add_u32(nw, IFLA_MAX_MTU, 9000);
	+ nlattr_add_u32(nw, IFLA_GROUP, 0);
	+*/
	+ get_stats(nw, ifp);
	+
	+ uint32_t val = (ifp->if_flags & IFF_PROMISC) != 0;
	+ nlattr_add_u32(nw, IFLA_PROMISCUITY, val);
	+
	+ if (nlmsg_end(nw))
	+ return (true);
	+
	+enomem:
	+ NL_LOG(LOG_DEBUG, "unable to dump interface %s state (ENOMEM)", if_name(ifp));
	+ nlmsg_abort(nw);
	+ return (false);
	+}
	+
	+static bool
	+check_ifmsg(void hdr, struct nl_pstate npt)
	+{
	+ struct ifinfomsg *ifm = hdr;
	+
	+ if (ifm->__ifi_pad != 0 \|\| ifm->ifi_type != 0 \|\|
	+ ifm->ifi_flags != 0 \|\| ifm->ifi_change != 0) {
	+ nlmsg_report_err_msg(npt,
	+ "strict checking: non-zero values in ifinfomsg header");
	+ return (false);
	+ }
	+
	+ return (true);
	+}
	+
	+#define _IN(_field) offsetof(struct ifinfomsg, _field)
	+#define _OUT(_field) offsetof(struct nl_parsed_link, _field)
	+static const struct nlfield_parser nlf_p_if[] = {
	+ { .off_in = _IN(ifi_type), .off_out = _OUT(ifi_type), .cb = nlf_get_u16 },
	+ { .off_in = _IN(ifi_index), .off_out = _OUT(ifi_index), .cb = nlf_get_u32 },
	+};
	+
	+static const struct nlattr_parser nla_p_linfo[] = {
	+ { .type = IFLA_INFO_KIND, .off = _OUT(ifla_cloner), .cb = nlattr_get_stringn },
	+ { .type = IFLA_INFO_DATA, .off = _OUT(ifla_idata), .cb = nlattr_get_nla },
	+};
	+NL_DECLARE_ATTR_PARSER(linfo_parser, nla_p_linfo);
	+
	+static const struct nlattr_parser nla_p_if[] = {
	+ { .type = IFLA_IFNAME, .off = _OUT(ifla_ifname), .cb = nlattr_get_string },
	+ { .type = IFLA_MTU, .off = _OUT(ifla_mtu), .cb = nlattr_get_uint32 },
	+ { .type = IFLA_LINK, .off = _OUT(ifi_index), .cb = nlattr_get_uint32 },
	+ { .type = IFLA_LINKINFO, .arg = &linfo_parser, .cb = nlattr_get_nested },
	+ { .type = IFLA_GROUP, .off = _OUT(ifla_group), .cb = nlattr_get_string },
	+ { .type = IFLA_ALT_IFNAME, .off = _OUT(ifla_ifname), .cb = nlattr_get_string },
	+};
	+#undef _IN
	+#undef _OUT
	+NL_DECLARE_STRICT_PARSER(ifmsg_parser, struct ifinfomsg, check_ifmsg, nlf_p_if, nla_p_if);
	+
	+static bool
	+match_iface(struct nl_parsed_link attrs, struct ifnet ifp)
	+{
	+ if (attrs->ifi_index != 0 && attrs->ifi_index != ifp->if_index)
	+ return (false);
	+ if (attrs->ifi_type != 0 && attrs->ifi_index != ifp->if_type)
	+ return (false);
	+ if (attrs->ifla_ifname != NULL && strcmp(attrs->ifla_ifname, if_name(ifp)))
	+ return (false);
	+ /* TODO: add group match */
	+
	+ return (true);
	+}
	+
	+/*
	+ * {nlmsg_len=52, nlmsg_type=RTM_GETLINK, nlmsg_flags=NLM_F_REQUEST, nlmsg_seq=1662842818, nlmsg_pid=0},
	+ * {ifi_family=AF_PACKET, ifi_type=ARPHRD_NETROM, ifi_index=0, ifi_flags=0, ifi_change=0},
	+ * [
	+ * [{nla_len=10, nla_type=IFLA_IFNAME}, "vnet9"],
	+ * [{nla_len=8, nla_type=IFLA_EXT_MASK}, RTEXT_FILTER_VF]
	+ * ]
	+ */
	+static int
	+rtnl_handle_getlink(struct nlmsghdr hdr, struct nlpcb nlp, struct nl_pstate *npt)
	+{
	+ struct epoch_tracker et;
	+ struct ifnet *ifp;
	+ int error = 0;
	+
	+ struct nl_parsed_link attrs = {};
	+ error = nl_parse_nlmsg(hdr, &ifmsg_parser, npt, &attrs);
	+ if (error != 0)
	+ return (error);
	+
	+ struct netlink_walkargs wa = {
	+ .so = nlp,
	+ .nw = npt->nw,
	+ .hdr.nlmsg_pid = hdr->nlmsg_pid,
	+ .hdr.nlmsg_seq = hdr->nlmsg_seq,
	+ .hdr.nlmsg_flags = hdr->nlmsg_flags \| NLM_F_MULTI,
	+ .hdr.nlmsg_type = NL_RTM_NEWLINK,
	+ };
	+
	+ /* Fast track for an interface w/ explicit index match */
	+ if (attrs.ifi_index != 0) {
	+ NET_EPOCH_ENTER(et);
	+ ifp = ifnet_byindex_ref(attrs.ifi_index);
	+ NET_EPOCH_EXIT(et);
	+ NLP_LOG(LOG_DEBUG3, nlp, "fast track -> searching index %u", attrs.ifi_index);
	+ if (ifp != NULL) {
	+ if (match_iface(&attrs, ifp)) {
	+ if (!dump_iface(wa.nw, ifp, &wa.hdr))
	+ error = ENOMEM;
	+ } else
	+ error = ESRCH;
	+ if_rele(ifp);
	+ } else
	+ error = ESRCH;
	+ return (error);
	+ }
	+
	+ /*
	+ * Fetching some link properties require performing ioctl's that may be blocking.
	+ * Address it by saving referenced pointers of the matching links,
	+ * exiting from epoch and going through the list one-by-one.
	+ */
	+
	+ NL_LOG(LOG_DEBUG2, "Start dump");
	+
	+ struct ifnet **match_array;
	+ int offset = 0, base_count = 16; /* start with 128 bytes */
	+ match_array = malloc(base_count * sizeof(void *), M_TEMP, M_NOWAIT);
	+
	+ NLP_LOG(LOG_DEBUG3, nlp, "MATCHING: index=%u type=%d name=%s",
	+ attrs.ifi_index, attrs.ifi_type, attrs.ifla_ifname);
	+ NET_EPOCH_ENTER(et);
	+ CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
	+ wa.count++;
	+ if (match_iface(&attrs, ifp)) {
	+ if (offset < base_count) {
	+ if (!if_try_ref(ifp))
	+ continue;
	+ match_array[offset++] = ifp;
	+ continue;
	+ }
	+ /* Too many matches, need to reallocate */
	+ struct ifnet **new_array;
	+ int sz = base_count * sizeof(void *);
	+ base_count *= 2;
	+ new_array = malloc(sz * 2, M_TEMP, M_NOWAIT);
	+ if (new_array == NULL) {
	+ error = ENOMEM;
	+ break;
	+ }
	+ memcpy(new_array, match_array, sz);
	+ free(match_array, M_TEMP);
	+ match_array = new_array;
	+ }
	+ }
	+ NET_EPOCH_EXIT(et);
	+
	+ NL_LOG(LOG_DEBUG2, "Matched %d interface(s), dumping", offset);
	+ for (int i = 0; error == 0 && i < offset; i++) {
	+ if (!dump_iface(wa.nw, match_array[i], &wa.hdr))
	+ error = ENOMEM;
	+ }
	+ for (int i = 0; i < offset; i++)
	+ if_rele(match_array[i]);
	+ free(match_array, M_TEMP);
	+
	+ NL_LOG(LOG_DEBUG2, "End dump, iterated %d dumped %d", wa.count, wa.dumped);
	+
	+ if (!nlmsg_end_dump(wa.nw, error, &wa.hdr)) {
	+ NL_LOG(LOG_DEBUG, "Unable to finalize the dump");
	+ return (ENOMEM);
	+ }
	+
	+ return (error);
	+}
	+
	+/*
	+ * sendmsg(3, {msg_name={sa_family=AF_NETLINK, nl_pid=0, nl_groups=00000000}, msg_namelen=12, msg_iov=[{iov_base=[
	+ * {nlmsg_len=60, nlmsg_type=RTM_NEWLINK, nlmsg_flags=NLM_F_REQUEST\|NLM_F_ACK\|NLM_F_EXCL\|NLM_F_CREATE, nlmsg_seq=1662715618, nlmsg_pid=0},
	+ * {ifi_family=AF_UNSPEC, ifi_type=ARPHRD_NETROM, ifi_index=0, ifi_flags=0, ifi_change=0},
	+ * {nla_len=11, nla_type=IFLA_IFNAME}, "dummy0"],
	+ * [
	+ * {nla_len=16, nla_type=IFLA_LINKINFO},
	+ * [
	+ * {nla_len=9, nla_type=IFLA_INFO_KIND}, "dummy"...
	+ * ]
	+ * ]
	+ */
	+
	+static int
	+rtnl_handle_dellink(struct nlmsghdr hdr, struct nlpcb nlp, struct nl_pstate *npt)
	+{
	+ struct epoch_tracker et;
	+ struct ifnet *ifp;
	+ int error;
	+
	+ struct nl_parsed_link attrs = {};
	+ error = nl_parse_nlmsg(hdr, &ifmsg_parser, npt, &attrs);
	+ if (error != 0)
	+ return (error);
	+
	+ NET_EPOCH_ENTER(et);
	+ ifp = ifnet_byindex_ref(attrs.ifi_index);
	+ NET_EPOCH_EXIT(et);
	+ if (ifp == NULL) {
	+ NLP_LOG(LOG_DEBUG, nlp, "unable to find interface %u", attrs.ifi_index);
	+ return (ENOENT);
	+ }
	+ NLP_LOG(LOG_DEBUG3, nlp, "mapped ifindex %u to %s", attrs.ifi_index, if_name(ifp));
	+
	+ sx_xlock(&ifnet_detach_sxlock);
	+ error = if_clone_destroy(if_name(ifp));
	+ sx_xunlock(&ifnet_detach_sxlock);
	+
	+ NLP_LOG(LOG_DEBUG2, nlp, "deleting interface %s returned %d", if_name(ifp), error);
	+
	+ if_rele(ifp);
	+ return (error);
	+}
	+
	+static int
	+rtnl_handle_newlink(struct nlmsghdr hdr, struct nlpcb nlp, struct nl_pstate *npt)
	+{
	+ struct nl_cloner *cloner;
	+ int error;
	+
	+ struct nl_parsed_link attrs = {};
	+ error = nl_parse_nlmsg(hdr, &ifmsg_parser, npt, &attrs);
	+ if (error != 0)
	+ return (error);
	+
	+ if (attrs.ifla_ifname == NULL \|\| strlen(attrs.ifla_ifname) == 0) {
	+ /* Applications like ip(8) verify RTM_NEWLINK existance
	+ * by calling it with empty arguments. Always return "innocent"
	+ * error.
	+ */
	+ NLMSG_REPORT_ERR_MSG(npt, "empty IFLA_IFNAME attribute");
	+ return (EPERM);
	+ }
	+
	+ if (attrs.ifla_cloner == NULL \|\| strlen(attrs.ifla_cloner) == 0) {
	+ NLMSG_REPORT_ERR_MSG(npt, "empty IFLA_INFO_KIND attribute");
	+ return (EINVAL);
	+ }
	+
	+ sx_slock(&rtnl_cloner_lock);
	+ SLIST_FOREACH(cloner, &nl_cloners, next) {
	+ if (!strcmp(attrs.ifla_cloner, cloner->name)) {
	+ error = cloner->create_f(&attrs, nlp, npt);
	+ sx_sunlock(&rtnl_cloner_lock);
	+ return (error);
	+ }
	+ }
	+ sx_sunlock(&rtnl_cloner_lock);
	+
	+ /* TODO: load cloner module if not exists & privilege permits */
	+ NLMSG_REPORT_ERR_MSG(npt, "interface type %s not supported", attrs.ifla_cloner);
	+ return (ENOTSUP);
	+
	+ return (error);
	+}
	+
	+/*
	+
	+{ifa_family=AF_INET, ifa_prefixlen=8, ifa_flags=IFA_F_PERMANENT, ifa_scope=RT_SCOPE_HOST, ifa_index=if_nametoindex("lo")},
	+ [
	+ {{nla_len=8, nla_type=IFA_ADDRESS}, inet_addr("127.0.0.1")},
	+ {{nla_len=8, nla_type=IFA_LOCAL}, inet_addr("127.0.0.1")},
	+ {{nla_len=7, nla_type=IFA_LABEL}, "lo"},
	+ {{nla_len=8, nla_type=IFA_FLAGS}, IFA_F_PERMANENT},
	+ {{nla_len=20, nla_type=IFA_CACHEINFO}, {ifa_prefered=4294967295, ifa_valid=4294967295, cstamp=3619, tstamp=3619}}]},
	+---
	+
	+{{len=72, type=RTM_NEWADDR, flags=NLM_F_MULTI, seq=1642191126, pid=566735},
	+ {ifa_family=AF_INET6, ifa_prefixlen=96, ifa_flags=IFA_F_PERMANENT, ifa_scope=RT_SCOPE_UNIVERSE, ifa_index=if_nametoindex("virbr0")},
	+ [
	+ {{nla_len=20, nla_type=IFA_ADDRESS}, inet_pton(AF_INET6, "2a01:4f8:13a:70c:ffff::1")},
	+ {{nla_len=20, nla_type=IFA_CACHEINFO}, {ifa_prefered=4294967295, ifa_valid=4294967295, cstamp=4283, tstamp=4283}},
	+ {{nla_len=8, nla_type=IFA_FLAGS}, IFA_F_PERMANENT}]},
	+*/
	+
	+static uint8_t
	+ifa_get_scope(const struct ifaddr *ifa)
	+{
	+ const struct sockaddr *sa;
	+ uint8_t addr_scope = RT_SCOPE_UNIVERSE;
	+
	+ sa = ifa->ifa_addr;
	+ switch (sa->sa_family) {
	+ case AF_INET:
	+ {
	+ struct in_addr addr;
	+ addr = ((const struct sockaddr_in *)sa)->sin_addr;
	+ if (IN_LOOPBACK(addr.s_addr))
	+ addr_scope = RT_SCOPE_HOST;
	+ else if (IN_LINKLOCAL(addr.s_addr))
	+ addr_scope = RT_SCOPE_LINK;
	+ break;
	+ }
	+ case AF_INET6:
	+ {
	+ const struct in6_addr *addr;
	+ addr = &((const struct sockaddr_in6 *)sa)->sin6_addr;
	+ if (IN6_IS_ADDR_LOOPBACK(addr))
	+ addr_scope = RT_SCOPE_HOST;
	+ else if (IN6_IS_ADDR_LINKLOCAL(addr))
	+ addr_scope = RT_SCOPE_LINK;
	+ break;
	+ }
	+ }
	+
	+ return (addr_scope);
	+}
	+
	+static uint8_t
	+inet6_get_plen(const struct in6_addr *addr)
	+{
	+
	+ return (bitcount32(addr->s6_addr32[0]) + bitcount32(addr->s6_addr32[1]) +
	+ bitcount32(addr->s6_addr32[2]) + bitcount32(addr->s6_addr32[3]));
	+}
	+
	+static uint8_t
	+get_sa_plen(const struct sockaddr *sa)
	+{
	+ const struct in6_addr *paddr6;
	+ const struct in_addr *paddr;
	+
	+ switch (sa->sa_family) {
	+ case AF_INET:
	+ if (sa == NULL)
	+ return (32);
	+ paddr = &(((const struct sockaddr_in *)sa)->sin_addr);
	+ return bitcount32(paddr->s_addr);;
	+ case AF_INET6:
	+ if (sa == NULL)
	+ return (128);
	+ paddr6 = &(((const struct sockaddr_in6 *)sa)->sin6_addr);
	+ return inet6_get_plen(paddr6);
	+ }
	+
	+ return (0);
	+}
	+
	+
	+/*
	+ * {'attrs': [('IFA_ADDRESS', '12.0.0.1'),
	+ ('IFA_LOCAL', '12.0.0.1'),
	+ ('IFA_LABEL', 'eth10'),
	+ ('IFA_FLAGS', 128),
	+ ('IFA_CACHEINFO', {'ifa_preferred': 4294967295, 'ifa_valid': 4294967295, 'cstamp': 63745746, 'tstamp': 63745746})],
	+ */
	+static bool
	+dump_iface_addr(struct nl_writer nw, struct ifnet ifp, struct ifaddr *ifa,
	+ const struct nlmsghdr *hdr)
	+{
	+ struct ifaddrmsg *ifamsg;
	+ struct sockaddr *sa = ifa->ifa_addr;
	+
	+ NL_LOG(LOG_DEBUG3, "dumping ifa %p type %s(%d) for interface %s",
	+ ifa, rib_print_family(sa->sa_family), sa->sa_family, if_name(ifp));
	+
	+ if (!nlmsg_reply(nw, hdr, sizeof(struct ifaddrmsg)))
	+ goto enomem;
	+
	+ ifamsg = nlmsg_reserve_object(nw, struct ifaddrmsg);
	+ ifamsg->ifa_family = sa->sa_family;
	+ ifamsg->ifa_prefixlen = get_sa_plen(ifa->ifa_netmask);
	+ ifamsg->ifa_flags = 0; // ifa_flags is useless
	+ ifamsg->ifa_scope = ifa_get_scope(ifa);
	+ ifamsg->ifa_index = ifp->if_index;
	+
	+ struct sockaddr *dst_sa = ifa->ifa_dstaddr;
	+ if ((dst_sa == NULL) \|\| (dst_sa->sa_family != sa->sa_family))
	+ dst_sa = sa;
	+ dump_sa(nw, IFA_ADDRESS, dst_sa);
	+ dump_sa(nw, IFA_LOCAL, sa);
	+ nlattr_add_string(nw, IFA_LABEL, if_name(ifp));
	+
	+ uint32_t val = 0; // ifa->ifa_flags;
	+ nlattr_add_u32(nw, IFA_FLAGS, val);
	+
	+ if (nlmsg_end(nw))
	+ return (true);
	+enomem:
	+ NL_LOG(LOG_DEBUG, "Failed to dump ifa type %s(%d) for interface %s",
	+ rib_print_family(sa->sa_family), sa->sa_family, if_name(ifp));
	+ nlmsg_abort(nw);
	+ return (false);
	+}
	+
	+static int
	+rtnl_handle_getaddr(struct nlmsghdr hdr, struct nlpcb nlp, struct nl_pstate *npt)
	+{
	+ struct ifaddr *ifa;
	+ struct ifnet *ifp;
	+ int error = 0;
	+
	+ struct netlink_walkargs wa = {
	+ .so = nlp,
	+ .nw = npt->nw,
	+ .hdr.nlmsg_pid = hdr->nlmsg_pid,
	+ .hdr.nlmsg_seq = hdr->nlmsg_seq,
	+ .hdr.nlmsg_flags = hdr->nlmsg_flags \| NLM_F_MULTI,
	+ .hdr.nlmsg_type = NL_RTM_NEWADDR,
	+ };
	+
	+ NL_LOG(LOG_DEBUG2, "Start dump");
	+
	+ CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
	+ CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
	+ if (wa.family != 0 && wa.family != ifa->ifa_addr->sa_family)
	+ continue;
	+ if (ifa->ifa_addr->sa_family == AF_LINK)
	+ continue;
	+ wa.count++;
	+ if (!dump_iface_addr(wa.nw, ifp, ifa, &wa.hdr)) {
	+ error = ENOMEM;
	+ break;
	+ }
	+ wa.dumped++;
	+ }
	+ if (error != 0)
	+ break;
	+ }
	+
	+ NL_LOG(LOG_DEBUG2, "End dump, iterated %d dumped %d", wa.count, wa.dumped);
	+
	+ if (!nlmsg_end_dump(wa.nw, error, &wa.hdr)) {
	+ NL_LOG(LOG_DEBUG, "Unable to finalize the dump");
	+ return (ENOMEM);
	+ }
	+
	+ return (error);
	+}
	+
	+static void
	+rtnl_handle_ifaddr(void arg __unused, struct ifaddr ifa, int cmd)
	+{
	+ struct nlmsghdr hdr = {};
	+ struct nl_writer nw = {};
	+ uint32_t group = 0;
	+
	+ switch (ifa->ifa_addr->sa_family) {
	+ case AF_INET:
	+ group = RTNLGRP_IPV4_IFADDR;
	+ break;
	+ case AF_INET6:
	+ group = RTNLGRP_IPV6_IFADDR;
	+ break;
	+ default:
	+ NL_LOG(LOG_DEBUG2, "ifa notification for unknown AF: %d",
	+ ifa->ifa_addr->sa_family);
	+ return;
	+ }
	+
	+ if (!nl_has_listeners(NETLINK_ROUTE, group))
	+ return;
	+
	+ if (!nlmsg_get_group_writer(&nw, NLMSG_LARGE, NETLINK_ROUTE, group)) {
	+ NL_LOG(LOG_DEBUG, "error allocating group writer");
	+ return;
	+ }
	+
	+ hdr.nlmsg_type = (cmd == RTM_DELETE) ? NL_RTM_DELADDR : NL_RTM_NEWADDR;
	+
	+ dump_iface_addr(&nw, ifa->ifa_ifp, ifa, &hdr);
	+ nlmsg_flush(&nw);
	+}
	+
	+static void
	+rtnl_handle_ifattach(void arg, struct ifnet ifp)
	+{
	+ struct nlmsghdr hdr = { .nlmsg_type = NL_RTM_NEWLINK };
	+ struct nl_writer nw = {};
	+
	+ if (!nl_has_listeners(NETLINK_ROUTE, RTNLGRP_LINK))
	+ return;
	+
	+ if (!nlmsg_get_group_writer(&nw, NLMSG_LARGE, NETLINK_ROUTE, RTNLGRP_LINK)) {
	+ NL_LOG(LOG_DEBUG, "error allocating mbuf");
	+ return;
	+ }
	+ dump_iface(&nw, ifp, &hdr);
	+ nlmsg_flush(&nw);
	+}
	+
	+static void
	+rtnl_handle_ifdetach(void arg, struct ifnet ifp)
	+{
	+ struct nlmsghdr hdr = { .nlmsg_type = NL_RTM_DELLINK };
	+ struct nl_writer nw = {};
	+
	+ if (!nl_has_listeners(NETLINK_ROUTE, RTNLGRP_LINK))
	+ return;
	+
	+ if (!nlmsg_get_group_writer(&nw, NLMSG_LARGE, NETLINK_ROUTE, RTNLGRP_LINK)) {
	+ NL_LOG(LOG_DEBUG, "error allocating mbuf");
	+ return;
	+ }
	+ dump_iface(&nw, ifp, &hdr);
	+ nlmsg_flush(&nw);
	+}
	+
	+static const struct rtnl_cmd_handler cmd_handlers[] = {
	+ {
	+ .cmd = NL_RTM_GETLINK,
	+ .name = "RTM_GETLINK",
	+ .cb = &rtnl_handle_getlink,
	+ .flags = RTNL_F_NOEPOCH,
	+ },
	+ {
	+ .cmd = NL_RTM_DELLINK,
	+ .name = "RTM_DELLINK",
	+ .cb = &rtnl_handle_dellink,
	+ .priv = PRIV_NET_IFDESTROY,
	+ .flags = RTNL_F_NOEPOCH,
	+ },
	+ {
	+ .cmd = NL_RTM_NEWLINK,
	+ .name = "RTM_NEWLINK",
	+ .cb = &rtnl_handle_newlink,
	+ .priv = PRIV_NET_IFCREATE,
	+ .flags = RTNL_F_NOEPOCH,
	+ },
	+ {
	+ .cmd = NL_RTM_GETADDR,
	+ .name = "RTM_GETADDR",
	+ .cb = &rtnl_handle_getaddr,
	+ },
	+ {
	+ .cmd = NL_RTM_NEWADDR,
	+ .name = "RTM_NEWADDR",
	+ .cb = &rtnl_handle_getaddr,
	+ },
	+ {
	+ .cmd = NL_RTM_DELADDR,
	+ .name = "RTM_DELADDR",
	+ .cb = &rtnl_handle_getaddr,
	+ },
	+};
	+
	+static const struct nlhdr_parser *all_parsers[] = { &ifmsg_parser };
	+
	+void
	+rtnl_iface_add_cloner(struct nl_cloner *cloner)
	+{
	+ sx_xlock(&rtnl_cloner_lock);
	+ SLIST_INSERT_HEAD(&nl_cloners, cloner, next);
	+ sx_xunlock(&rtnl_cloner_lock);
	+}
	+
	+void rtnl_iface_del_cloner(struct nl_cloner *cloner)
	+{
	+ sx_xlock(&rtnl_cloner_lock);
	+ SLIST_REMOVE(&nl_cloners, cloner, nl_cloner, next);
	+ sx_xunlock(&rtnl_cloner_lock);
	+}
	+
	+void
	+rtnl_ifaces_init(void)
	+{
	+ ifattach_event = EVENTHANDLER_REGISTER(
	+ ifnet_arrival_event, rtnl_handle_ifattach, NULL,
	+ EVENTHANDLER_PRI_ANY);
	+ ifdetach_event = EVENTHANDLER_REGISTER(
	+ ifnet_departure_event, rtnl_handle_ifdetach, NULL,
	+ EVENTHANDLER_PRI_ANY);
	+ ifaddr_event = EVENTHANDLER_REGISTER(
	+ rt_addrmsg, rtnl_handle_ifaddr, NULL,
	+ EVENTHANDLER_PRI_ANY);
	+ NL_VERIFY_PARSERS(all_parsers);
	+ rtnl_iface_drivers_register();
	+ rtnl_register_messages(cmd_handlers, NL_ARRAY_LEN(cmd_handlers));
	+}
	+
	+void
	+rtnl_ifaces_destroy(void)
	+{
	+ EVENTHANDLER_DEREGISTER(ifnet_arrival_event, ifattach_event);
	+ EVENTHANDLER_DEREGISTER(ifnet_departure_event, ifdetach_event);
	+ EVENTHANDLER_DEREGISTER(rt_addrmsg, ifaddr_event);
	+}
	diff --git a/sys/netlink/route/iface_drivers.c b/sys/netlink/route/iface_drivers.c
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/route/iface_drivers.c
	@@ -0,0 +1,165 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+#include <sys/cdefs.h>
	+__FBSDID("$FreeBSD$");
	+#include "opt_inet.h"
	+#include "opt_inet6.h"
	+#include <sys/types.h>
	+#include <sys/malloc.h>
	+#include <sys/socket.h>
	+#include <sys/sockio.h>
	+#include <sys/syslog.h>
	+#include <sys/socketvar.h>
	+
	+#include <net/ethernet.h>
	+#include <net/if.h>
	+#include <net/if_dl.h>
	+#include <net/if_media.h>
	+#include <net/if_var.h>
	+#include <net/if_clone.h>
	+#include <net/if_vlan_var.h>
	+#include <net/route.h>
	+#include <net/route/nhop.h>
	+#include <net/route/route_ctl.h>
	+#include <netlink/netlink.h>
	+#include <netlink/netlink_ctl.h>
	+#include <netlink/netlink_route.h>
	+#include <netlink/route/route_var.h>
	+
	+#include <netinet6/scope6_var.h> /* scope deembedding */
	+
	+#define DEBUG_MOD_NAME nl_iface_drivers
	+#define DEBUG_MAX_LEVEL LOG_DEBUG3
	+#include <netlink/netlink_debug.h>
	+_DECLARE_DEBUG(LOG_DEBUG);
	+
	+/*
	+ *
	+ * {len=76, type=RTM_NEWLINK, flags=NLM_F_REQUEST\|NLM_F_ACK\|NLM_F_EXCL\|NLM_F_CREATE, seq=1662892737, pid=0},
	+ * {ifi_family=AF_UNSPEC, ifi_type=ARPHRD_NETROM, ifi_index=0, ifi_flags=0, ifi_change=0},
	+ * [
	+ * {{nla_len=8, nla_type=IFLA_LINK}, 2},
	+ * {{nla_len=12, nla_type=IFLA_IFNAME}, "xvlan22"},
	+ * {{nla_len=24, nla_type=IFLA_LINKINFO},
	+ * [
	+ * {{nla_len=8, nla_type=IFLA_INFO_KIND}, "vlan"...},
	+ * {{nla_len=12, nla_type=IFLA_INFO_DATA}, "\x06\x00\x01\x00\x16\x00\x00\x00"}]}]}, iov_len=76}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 76
	+ */
	+
	+struct nl_parsed_vlan {
	+ uint16_t vlan_id;
	+ uint16_t vlan_proto;
	+ struct ifla_vlan_flags vlan_flags;
	+};
	+
	+#define _OUT(_field) offsetof(struct nl_parsed_vlan, _field)
	+static const struct nlattr_parser nla_p_vlan[] = {
	+ { .type = IFLA_VLAN_ID, .off = _OUT(vlan_id), .cb = nlattr_get_uint16 },
	+ { .type = IFLA_VLAN_FLAGS, .off = _OUT(vlan_flags), .cb = nlattr_get_nla },
	+ { .type = IFLA_VLAN_PROTOCOL, .off = _OUT(vlan_proto), .cb = nlattr_get_uint16 },
	+};
	+#undef _OUT
	+NL_DECLARE_ATTR_PARSER(vlan_parser, nla_p_vlan);
	+
	+static int
	+create_vlan(struct nl_parsed_link lattrs, struct nlpcb nlp, struct nl_pstate *npt)
	+{
	+ struct epoch_tracker et;
	+ struct ifnet *ifp;
	+ int error;
	+
	+ /*
	+ * lattrs.ifla_ifname is the new interface name
	+ * lattrs.ifi_index contains parent interface index
	+ * lattrs.ifla_idata contains un-parsed vlan data
	+ */
	+
	+ struct nl_parsed_vlan attrs = {
	+ .vlan_id = 0xFEFE,
	+ .vlan_proto = ETHERTYPE_VLAN
	+ };
	+ NLP_LOG(LOG_DEBUG3, nlp, "nested: %p len %d", lattrs->ifla_idata, lattrs->ifla_idata->nla_len);
	+
	+ if (lattrs->ifla_idata == NULL) {
	+ NLMSG_REPORT_ERR_MSG(npt, "vlan id is required, guessing not supported");
	+ return (ENOTSUP);
	+ }
	+
	+ error = nl_parse_nested(lattrs->ifla_idata, &vlan_parser, npt, &attrs);
	+ if (error != 0)
	+ return (error);
	+ if (attrs.vlan_id > 4095) {
	+ NLMSG_REPORT_ERR_MSG(npt, "Invalid VID: %d", attrs.vlan_id);
	+ return (EINVAL);
	+ }
	+ if (attrs.vlan_proto != ETHERTYPE_VLAN && attrs.vlan_proto != ETHERTYPE_QINQ) {
	+ NLMSG_REPORT_ERR_MSG(npt, "Unsupported ethertype: 0x%04X", attrs.vlan_proto);
	+ return (ENOTSUP);
	+ }
	+
	+ NET_EPOCH_ENTER(et);
	+ ifp = ifnet_byindex_ref(lattrs->ifi_index);
	+ NET_EPOCH_EXIT(et);
	+ if (ifp == NULL) {
	+ NLP_LOG(LOG_DEBUG, nlp, "unable to find parent interface %u",
	+ lattrs->ifi_index);
	+ return (ENOENT);
	+ }
	+
	+ /* Waiting till if_clone changes lands */
	+/*
	+ struct vlanreq params = {
	+ .vlr_tag = attrs.vlan_id,
	+ .vlr_proto = attrs.vlan_proto,
	+ };
	+*/
	+ int ifname_len = strlen(lattrs->ifla_ifname) + 1;
	+ error = if_clone_create(lattrs->ifla_ifname, ifname_len, (char *)NULL);
	+
	+ NLP_LOG(LOG_DEBUG2, nlp, "clone for %s returned %d", lattrs->ifla_ifname, error);
	+
	+ if_rele(ifp);
	+ return (error);
	+}
	+
	+static struct nl_cloner vlan_cloner = {
	+ .name = "vlan",
	+ .create_f = create_vlan,
	+
	+};
	+
	+static const struct nlhdr_parser *all_parsers[] = { &vlan_parser };
	+
	+void
	+rtnl_iface_drivers_register(void)
	+{
	+ rtnl_iface_add_cloner(&vlan_cloner);
	+ NL_VERIFY_PARSERS(all_parsers);
	+}
	+
	+
	diff --git a/sys/netlink/route/ifaddrs.h b/sys/netlink/route/ifaddrs.h
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/route/ifaddrs.h
	@@ -0,0 +1,90 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+/*
	+ * Interface address-related (RTM_<NEW\|DEL\|GET>ADDR) message header and attributes.
	+ */
	+
	+#ifndef _NETLINK_ROUTE_IFADDRS_H_
	+#define _NETLINK_ROUTE_IFADDRS_H_
	+
	+/* Base header for all of the relevant messages */
	+struct ifaddrmsg {
	+ uint8_t ifa_family; /* Address family */
	+ uint8_t ifa_prefixlen; /* Prefix length */
	+ uint8_t ifa_flags; /* Address-specific flags */
	+ uint8_t ifa_scope; /* Address scope */
	+ uint32_t ifa_index; /* Link ifindex */
	+};
	+
	+#ifndef _KERNEL
	+#define _NL_IFA_HDRLEN ((int)sizeof(struct ifaddrmsg))
	+#define IFA_RTA(_ifa) ((struct rtattr *)(NL_ITEM_DATA(_ifa, _NL_IFA_HDRLEN)))
	+#define IFA_PAYLOAD(_hdr) NLMSG_PAYLOAD(_hdr, _NL_IFA_HDRLEN)
	+#endif
	+
	+/* Defined attributes */
	+enum {
	+ IFA_UNSPEC,
	+ IFA_ADDRESS = 1, /* binary, prefix address (destination for p2p) */
	+ IFA_LOCAL = 2, /* binary, interface address */
	+ IFA_LABEL = 3, /* not supported */
	+ IFA_BROADCAST = 4, /* binary, broadcast ifa */
	+ IFA_ANYCAST = 5, /* not supported */
	+ IFA_CACHEINFO = 6, /* not supported */
	+ IFA_MULTICAST = 7, /* not supported */
	+ IFA_FLAGS = 8, /* not supported */
	+ IFA_RT_PRIORITY = 9, /* not supported */
	+ IFA_TARGET_NETNSID = 10, /* not supported */
	+ __IFA_MAX,
	+};
	+#define IFA_MAX (__IFA_MAX - 1)
	+
	+/* IFA_FLAGS attribute flags */
	+#define IFA_F_SECONDARY 0x0001
	+#define IFA_F_TEMPORARY IFA_F_SECONDARY
	+#define IFA_F_NODAD 0x0002
	+#define IFA_F_OPTIMISTIC 0x0004
	+#define IFA_F_DADFAILED 0x0008
	+#define IFA_F_HOMEADDRESS 0x0010
	+#define IFA_F_DEPRECATED 0x0020
	+#define IFA_F_TENTATIVE 0x0040
	+#define IFA_F_PERMANENT 0x0080
	+#define IFA_F_MANAGETEMPADDR 0x0100
	+#define IFA_F_NOPREFIXROUTE 0x0200
	+#define IFA_F_MCAUTOJOIN 0x0400
	+#define IFA_F_STABLE_PRIVACY 0x0800
	+
	+/* IFA_CACHEINFO value */
	+struct ifa_cacheinfo {
	+ uint32_t ifa_prefered;
	+ uint32_t ifa_valid;
	+ uint32_t cstamp;
	+ uint32_t tstamp;
	+};
	+
	+#endif
	diff --git a/sys/netlink/route/interface.h b/sys/netlink/route/interface.h
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/route/interface.h
	@@ -0,0 +1,245 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+/*
	+ * Interface-related (RTM_<NEW\|DEL\|GET\|SET>LINK) message header and attributes.
	+ */
	+
	+#ifndef _NETLINK_ROUTE_INTERFACE_H_
	+#define _NETLINK_ROUTE_INTERFACE_H_
	+
	+/* Base header for all of the relevant messages */
	+struct ifinfomsg {
	+ unsigned char ifi_family; /* not used */
	+ unsigned char __ifi_pad;
	+ unsigned short ifi_type; /* ARPHRD_* */
	+ int ifi_index; /* Inteface index */
	+ unsigned ifi_flags; /* IFF_* flags */
	+ unsigned ifi_change; /* IFF_* change mask */
	+};
	+
	+#ifndef _KERNEL
	+/* Compatilbility helpers */
	+#define _IFINFO_HDRLEN ((int)sizeof(struct ifinfomsg))
	+#define IFLA_RTA(_ifi) ((struct rtattr *)NL_ITEM_DATA(_ifi, _IFINFO_HDRLEN))
	+#define IFLA_PAYLOAD(_ifi) NLMSG_PAYLOAD(_ifi, _IFINFO_HDRLEN)
	+#endif
	+
	+enum {
	+ IFLA_UNSPEC = 0,
	+ IFLA_ADDRESS = 1, /* binary: Link-level address (MAC) */
	+#define IFLA_ADDRESS IFLA_ADDRESS
	+ IFLA_BROADCAST = 2, /* binary: link-level broadcast address */
	+#define IFLA_BROADCAST IFLA_BROADCAST
	+ IFLA_IFNAME = 3, /* string: Interface name */
	+#define IFLA_IFNAME IFLA_IFNAME
	+ IFLA_MTU = 4, /* u32: Current interface L3 mtu */
	+#define IFLA_MTU IFLA_MTU
	+ IFLA_LINK = 5, /* u32: interface index */
	+#define IFLA_LINK IFLA_LINK
	+ IFLA_QDISC = 6, /* string: Queing policy (not supported) */
	+#define IFLA_QDISC IFLA_QDISC
	+ IFLA_STATS = 7, /* Interface counters */
	+#define IFLA_STATS IFLA_STATS
	+ IFLA_COST = 8, /* not supported */
	+#define IFLA_COST IFLA_COST
	+ IFLA_PRIORITY = 9, /* not supported */
	+#define IFLA_PRIORITY IFLA_PRIORITY
	+ IFLA_MASTER = 10, /* u32: parent interface ifindex */
	+#define IFLA_MASTER IFLA_MASTER
	+ IFLA_WIRELESS = 11, /* not supported */
	+#define IFLA_WIRELESS IFLA_WIRELESS
	+ IFLA_PROTINFO = 12, /* protocol-specific data */
	+#define IFLA_PROTINFO IFLA_PROTINFO
	+ IFLA_TXQLEN = 13, /* u32: transmit queue length */
	+#define IFLA_TXQLEN IFLA_TXQLEN
	+ IFLA_MAP = 14, /* not supported */
	+#define IFLA_MAP IFLA_MAP
	+ IFLA_WEIGHT = 15, /* not supported */
	+#define IFLA_WEIGHT IFLA_WEIGHT
	+ IFLA_OPERSTATE = 16, /* u8: ifOperStatus per RFC 2863 */
	+#define IFLA_OPERSTATE IFLA_OPERSTATE
	+ IFLA_LINKMODE = 17, /* u8: ifmedia (not supported) */
	+#define IFLA_LINKMODE IFLA_LINKMODE
	+ IFLA_LINKINFO = 18, /* nested: IFLA_INFO_ */
	+#define IFLA_LINKINFO IFLA_LINKINFO
	+ IFLA_NET_NS_PID = 19, /* u32: vnet id (not supported) */
	+#define IFLA_NET_NS_PID IFLA_NET_NS_PID
	+ IFLA_IFALIAS = 20, /* not supported */
	+#define IFLA_IFALIAS IFLA_IFALIAS
	+ IFLA_NUM_VF = 21, /* not supported */
	+#define IFLA_NUM_VF IFLA_NUM_VF
	+ IFLA_VFINFO_LIST= 22, /* not supported */
	+#define IFLA_VFINFO_LIST IFLA_VFINFO_LIST
	+ IFLA_STATS64 = 23, /* rtnl_link_stats64: iface stats */
	+#define IFLA_STATS64 IFLA_STATS64
	+ IFLA_VF_PORTS,
	+ IFLA_PORT_SELF,
	+ IFLA_AF_SPEC,
	+ IFLA_GROUP, /* Group the device belongs to */
	+ IFLA_NET_NS_FD,
	+ IFLA_EXT_MASK, /* Extended info mask, VFs, etc */
	+ IFLA_PROMISCUITY, /* Promiscuity count: > 0 means acts PROMISC */
	+#define IFLA_PROMISCUITY IFLA_PROMISCUITY
	+ IFLA_NUM_TX_QUEUES,
	+ IFLA_NUM_RX_QUEUES,
	+ IFLA_CARRIER,
	+ IFLA_PHYS_PORT_ID,
	+ IFLA_CARRIER_CHANGES,
	+ IFLA_PHYS_SWITCH_ID,
	+ IFLA_LINK_NETNSID,
	+ IFLA_PHYS_PORT_NAME,
	+ IFLA_PROTO_DOWN,
	+ IFLA_GSO_MAX_SEGS,
	+ IFLA_GSO_MAX_SIZE,
	+ IFLA_PAD,
	+ IFLA_XDP,
	+ IFLA_EVENT,
	+ IFLA_NEW_NETNSID,
	+ IFLA_IF_NETNSID,
	+ IFLA_TARGET_NETNSID = IFLA_IF_NETNSID, /* new alias */
	+ IFLA_CARRIER_UP_COUNT,
	+ IFLA_CARRIER_DOWN_COUNT,
	+ IFLA_NEW_IFINDEX,
	+ IFLA_MIN_MTU,
	+ IFLA_MAX_MTU,
	+ IFLA_PROP_LIST,
	+ IFLA_ALT_IFNAME, /* Alternative ifname */
	+ IFLA_PERM_ADDRESS,
	+ IFLA_PROTO_DOWN_REASON,
	+ __IFLA_MAX
	+};
	+#define IFLA_MAX (__IFLA_MAX - 1)
	+
	+/*
	+ * Attributes that can be used as filters:
	+ * IFLA_IFNAME, IFLA_GROUP, IFLA_ALT_IFNAME
	+ * Headers that can be used as filters:
	+ * ifi_index, ifi_type
	+ */
	+
	+/*
	+ * IFLA_OPERSTATE.
	+ * The values below represent the possible
	+ * states of ifOperStatus defined by RFC 2863
	+ */
	+enum {
	+ IF_OPER_UNKNOWN = 0, /* status can not be determined */
	+ IF_OPER_NOTPRESENT = 1, /* some (hardware) component not present */
	+ IF_OPER_DOWN = 2, /* down */
	+ IF_OPER_LOWERLAYERDOWN = 3, /* some lower-level interface is down */
	+ IF_OPER_TESTING = 4, /* in some test mode */
	+ IF_OPER_DORMANT = 5, /* "up" but waiting for some condition (802.1X) */
	+ IF_OPER_UP = 6, /* ready to pass packets */
	+};
	+
	+/* IFLA_STATS */
	+struct rtnl_link_stats {
	+ uint32_t rx_packets; /* total RX packets (IFCOUNTER_IPACKETS) */
	+ uint32_t tx_packets; /* total TX packets (IFCOUNTER_OPACKETS) */
	+ uint32_t rx_bytes; /* total RX bytes (IFCOUNTER_IBYTES) */
	+ uint32_t tx_bytes; /* total TX bytes (IFCOUNTER_OBYTES) */
	+ uint32_t rx_errors; /* RX errors (IFCOUNTER_IERRORS) */
	+ uint32_t tx_errors; /* RX errors (IFCOUNTER_OERRORS) */
	+ uint32_t rx_dropped; /* RX drop (no space in ring/no bufs) (IFCOUNTER_IQDROPS) */
	+ uint32_t tx_dropped; /* TX drop (IFCOUNTER_OQDROPS) */
	+ uint32_t multicast; /* RX multicast packets (IFCOUNTER_IMCASTS) */
	+ uint32_t collisions; /* not supported */
	+ uint32_t rx_length_errors; /* not supported */
	+ uint32_t rx_over_errors; /* not supported */
	+ uint32_t rx_crc_errors; /* not supported */
	+ uint32_t rx_frame_errors; /* not supported */
	+ uint32_t rx_fifo_errors; /* not supported */
	+ uint32_t rx_missed_errors; /* not supported */
	+ uint32_t tx_aborted_errors; /* not supported */
	+ uint32_t tx_carrier_errors; /* not supported */
	+ uint32_t tx_fifo_errors; /* not supported */
	+ uint32_t tx_heartbeat_errors; /* not supported */
	+ uint32_t tx_window_errors; /* not supported */
	+ uint32_t rx_compressed; /* not supported */
	+ uint32_t tx_compressed; /* not supported */
	+ uint32_t rx_nohandler; /* dropped due to no proto handler (IFCOUNTER_NOPROTO) */
	+};
	+
	+/* IFLA_STATS64 */
	+struct rtnl_link_stats64 {
	+ uint64_t rx_packets; /* total RX packets (IFCOUNTER_IPACKETS) */
	+ uint64_t tx_packets; /* total TX packets (IFCOUNTER_OPACKETS) */
	+ uint64_t rx_bytes; /* total RX bytes (IFCOUNTER_IBYTES) */
	+ uint64_t tx_bytes; /* total TX bytes (IFCOUNTER_OBYTES) */
	+ uint64_t rx_errors; /* RX errors (IFCOUNTER_IERRORS) */
	+ uint64_t tx_errors; /* RX errors (IFCOUNTER_OERRORS) */
	+ uint64_t rx_dropped; /* RX drop (no space in ring/no bufs) (IFCOUNTER_IQDROPS) */
	+ uint64_t tx_dropped; /* TX drop (IFCOUNTER_OQDROPS) */
	+ uint64_t multicast; /* RX multicast packets (IFCOUNTER_IMCASTS) */
	+ uint64_t collisions; /* not supported */
	+ uint64_t rx_length_errors; /* not supported */
	+ uint64_t rx_over_errors; /* not supported */
	+ uint64_t rx_crc_errors; /* not supported */
	+ uint64_t rx_frame_errors; /* not supported */
	+ uint64_t rx_fifo_errors; /* not supported */
	+ uint64_t rx_missed_errors; /* not supported */
	+ uint64_t tx_aborted_errors; /* not supported */
	+ uint64_t tx_carrier_errors; /* not supported */
	+ uint64_t tx_fifo_errors; /* not supported */
	+ uint64_t tx_heartbeat_errors; /* not supported */
	+ uint64_t tx_window_errors; /* not supported */
	+ uint64_t rx_compressed; /* not supported */
	+ uint64_t tx_compressed; /* not supported */
	+ uint64_t rx_nohandler; /* dropped due to no proto handler (IFCOUNTER_NOPROTO) */
	+};
	+
	+/* IFLA_LINKINFO child nlattr types */
	+enum {
	+ IFLA_INFO_UNSPEC,
	+ IFLA_INFO_KIND = 1, /* string, link type ("vlan") */
	+ IFLA_INFO_DATA = 2, /* Per-link-type custom data */
	+ IFLA_INFO_XSTATS = 3,
	+ IFLA_INFO_SLAVE_KIND = 4,
	+ IFLA_INFO_SLAVE_DATA = 5,
	+ __IFLA_INFO_MAX,
	+};
	+#define IFLA_INFO_MAX (__IFLA_INFO_MAX - 1)
	+
	+/* IFLA_INFO_DATA vlan attributes */
	+enum {
	+ IFLA_VLAN_UNSPEC,
	+ IFLA_VLAN_ID,
	+ IFLA_VLAN_FLAGS,
	+ IFLA_VLAN_EGRESS_QOS,
	+ IFLA_VLAN_INGRESS_QOS,
	+ IFLA_VLAN_PROTOCOL,
	+ __IFLA_VLAN_MAX,
	+};
	+
	+#define IFLA_VLAN_MAX (__IFLA_VLAN_MAX - 1)
	+struct ifla_vlan_flags {
	+ uint32_t flags;
	+ uint32_t mask;
	+};
	+
	+#endif
	diff --git a/sys/netlink/route/neigh.h b/sys/netlink/route/neigh.h
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/route/neigh.h
	@@ -0,0 +1,105 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+/*
	+ * Neighbors-related (RTM_<NEW\|DEL\|GET>NEIGH) message header and attributes.
	+ */
	+
	+#ifndef _NETLINK_ROUTE_NEIGH_H_
	+#define _NETLINK_ROUTE_NEIGH_H_
	+
	+/* Base header for all of the relevant messages */
	+struct ndmsg {
	+ uint8_t ndm_family;
	+ uint8_t ndm_pad1;
	+ uint16_t ndm_pad2;
	+ int32_t ndm_ifindex;
	+ uint16_t ndm_state;
	+ uint8_t ndm_flags;
	+ uint8_t ndm_type;
	+};
	+
	+/* Attributes */
	+enum {
	+ NDA_UNSPEC,
	+ NDA_DST, /* binary: neigh l3 address */
	+ NDA_LLADDR, /* binary: neigh link-level address */
	+ NDA_CACHEINFO, /* binary, struct nda_cacheinfo */
	+ NDA_PROBES, /* XXX */
	+ NDA_VLAN, /* upper 802.1Q tag */
	+ NDA_PORT, /* not supported */
	+ NDA_VNI, /* not supported */
	+ NDA_IFINDEX, /* interface index */
	+ NDA_MASTER, /* not supported */
	+ NDA_LINK_NETNSID, /* not supported */
	+ NDA_SRC_VNI, /* not supported */
	+ NDA_PROTOCOL, /* XXX */
	+ NDA_NH_ID, /* not supported */
	+ NDA_FDB_EXT_ATTRS, /* not supported */
	+ NDA_FLAGS_EXT, /* u32: ndm_flags */
	+ NDA_NDM_STATE_MASK, /* XXX */
	+ NDA_NDM_FLAGS_MASK, /* XXX */
	+ __NDA_MAX
	+};
	+
	+#define NDA_MAX (__NDA_MAX - 1)
	+
	+
	+/* ndm_flags / NDA_FLAGS_EXT */
	+#define NTF_USE 0x0001 /* XXX */
	+#define NTF_SELF 0x0002 /* local station */
	+#define NTF_MASTER 0x0004 /* XXX */
	+#define NTF_PROXY 0x0008 /* proxy entry */
	+#define NTF_EXT_LEARNED 0x0010 /* not used */
	+#define NTF_OFFLOADED 0x0020 /* not used */
	+#define NTF_STICKY 0x0040 /* permament entry */
	+#define NTF_ROUTER 0x0080 /* dst indicated itself as a router */
	+/* start of NDA_FLAGS_EXT */
	+#define NTF_EXT_MANAGED 0x0100 /* not used */
	+
	+/* ndm_state */
	+#define NUD_INCOMPLETE 0x01 /* No lladdr, address resolution in progress */
	+#define NUD_REACHABLE 0x02 /* reachable & recently resolved */
	+#define NUD_STALE 0x04 /* has lladdr but it's stale */
	+#define NUD_DELAY 0x08 /* has lladdr, is stale, probes delayed */
	+#define NUD_PROBE 0x10 /* has lladdr, is stale, probes sent */
	+#define NUD_FAILED 0x20 /* unused */
	+
	+/* Dummy states */
	+#define NUD_NOARP 0x40 /* not used */
	+#define NUD_PERMANENT 0x80 /* not flushed */
	+#define NUD_NONE 0x00
	+
	+/* NDA_CACHEINFO */
	+struct nda_cacheinfo {
	+ uint32_t ndm_confirmed; /* seconds since ARP/ND was received from neigh */
	+ uint32_t ndm_used; /* seconds since last used (not provided) */
	+ uint32_t ndm_updated; /* seconds since state was updated last */
	+ uint32_t ndm_refcnt; /* number of references held */
	+};
	+
	+#endif
	diff --git a/sys/netlink/route/neigh.c b/sys/netlink/route/neigh.c
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/route/neigh.c
	@@ -0,0 +1,571 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+#include <sys/cdefs.h>
	+__FBSDID("$FreeBSD$");
	+#include "opt_inet.h"
	+#include "opt_inet6.h"
	+#include <sys/types.h>
	+#include <sys/malloc.h>
	+#include <sys/socket.h>
	+#include <sys/syslog.h>
	+
	+#include <net/if.h>
	+#include <net/if_llatbl.h>
	+#include <netlink/netlink.h>
	+#include <netlink/netlink_ctl.h>
	+#include <netlink/netlink_route.h>
	+#include <netlink/route/route_var.h>
	+
	+#include <netinet6/in6_var.h> /* nd6.h requires this */
	+#include <netinet6/nd6.h> /* nd6 state machine */
	+#include <netinet6/scope6_var.h> /* scope deembedding */
	+
	+#define DEBUG_MOD_NAME nl_neigh
	+#define DEBUG_MAX_LEVEL LOG_DEBUG3
	+#include <netlink/netlink_debug.h>
	+_DECLARE_DEBUG(LOG_DEBUG);
	+
	+static int lle_families[] = { AF_INET, AF_INET6 };
	+
	+static eventhandler_tag lle_event_p;
	+
	+struct netlink_walkargs {
	+ struct nl_writer *nw;
	+ struct nlmsghdr hdr;
	+ struct nlpcb *so;
	+ struct ifnet *ifp;
	+ int family;
	+ int error;
	+ int count;
	+ int dumped;
	+};
	+
	+static int
	+lle_state_to_nl_state(int family, struct llentry *lle)
	+{
	+ int state = lle->ln_state;
	+
	+ switch (family) {
	+ case AF_INET:
	+ if (lle->la_flags & (LLE_STATIC \| LLE_IFADDR))
	+ state = 1;
	+ switch (state) {
	+ case 0: /* ARP_LLINFO_INCOMPLETE */
	+ return (NUD_INCOMPLETE);
	+ case 1: /* ARP_LLINFO_REACHABLE */
	+ return (NUD_REACHABLE);
	+ case 2: /* ARP_LLINFO_VERIFY */
	+ return (NUD_PROBE);
	+ }
	+ break;
	+ case AF_INET6:
	+ switch (state) {
	+ case ND6_LLINFO_INCOMPLETE:
	+ return (NUD_INCOMPLETE);
	+ case ND6_LLINFO_REACHABLE:
	+ return (NUD_REACHABLE);
	+ case ND6_LLINFO_STALE:
	+ return (NUD_STALE);
	+ case ND6_LLINFO_DELAY:
	+ return (NUD_DELAY);
	+ case ND6_LLINFO_PROBE:
	+ return (NUD_PROBE);
	+ }
	+ break;
	+ }
	+
	+ return (NUD_NONE);
	+}
	+
	+static uint32_t
	+lle_flags_to_nl_flags(const struct llentry *lle)
	+{
	+ uint32_t nl_flags = 0;
	+
	+ if (lle->la_flags & LLE_IFADDR)
	+ nl_flags \|= NTF_SELF;
	+ if (lle->la_flags & LLE_PUB)
	+ nl_flags \|= NTF_PROXY;
	+ if (lle->la_flags & LLE_STATIC)
	+ nl_flags \|= NTF_STICKY;
	+ if (lle->ln_router != 0)
	+ nl_flags \|= NTF_ROUTER;
	+
	+ return (nl_flags);
	+}
	+
	+static int
	+dump_lle_locked(struct llentry lle, void arg)
	+{
	+ struct netlink_walkargs wa = (struct netlink_walkargs )arg;
	+ struct nlmsghdr *hdr = &wa->hdr;
	+ struct nl_writer *nw = wa->nw;
	+ struct ndmsg *ndm;
	+ union {
	+ struct in_addr in;
	+ struct in6_addr in6;
	+ } addr;
	+
	+ IF_DEBUG_LEVEL(LOG_DEBUG2) {
	+ char llebuf[NHOP_PRINT_BUFSIZE];
	+ llentry_print_buf_lltable(lle, llebuf, sizeof(llebuf));
	+ NL_LOG(LOG_DEBUG2, "dumping %s", llebuf);
	+ }
	+
	+ if (!nlmsg_reply(nw, hdr, sizeof(struct ndmsg)))
	+ goto enomem;
	+
	+ ndm = nlmsg_reserve_object(nw, struct ndmsg);
	+ ndm->ndm_family = wa->family;
	+ ndm->ndm_ifindex = wa->ifp->if_index;
	+ ndm->ndm_state = lle_state_to_nl_state(wa->family, lle);
	+ ndm->ndm_flags = lle_flags_to_nl_flags(lle);
	+
	+ switch (wa->family) {
	+#ifdef INET
	+ case AF_INET:
	+ addr.in = lle->r_l3addr.addr4;
	+ nlattr_add(nw, NDA_DST, 4, &addr);
	+ break;
	+#endif
	+#ifdef INET6
	+ case AF_INET6:
	+ addr.in6 = lle->r_l3addr.addr6;
	+ in6_clearscope(&addr.in6);
	+ nlattr_add(nw, NDA_DST, 16, &addr);
	+ break;
	+#endif
	+ }
	+
	+ if (lle->r_flags & RLLE_VALID) {
	+ /* Has L2 */
	+ int addrlen = wa->ifp->if_addrlen;
	+ nlattr_add(nw, NDA_LLADDR, addrlen, lle->ll_addr);
	+ }
	+
	+ nlattr_add_u32(nw, NDA_PROBES, lle->la_asked);
	+
	+ struct nda_cacheinfo *cache;
	+ cache = nlmsg_reserve_attr(nw, NDA_CACHEINFO, struct nda_cacheinfo);
	+ if (cache == NULL)
	+ goto enomem;
	+ /* TODO: provide confirmed/updated */
	+ cache->ndm_refcnt = lle->lle_refcnt;
	+
	+ if (nlmsg_end(nw))
	+ return (0);
	+enomem:
	+ NL_LOG(LOG_DEBUG, "unable to dump lle state (ENOMEM)");
	+ nlmsg_abort(nw);
	+ return (ENOMEM);
	+}
	+
	+static int
	+dump_lle(struct lltable llt, struct llentry lle, void *arg)
	+{
	+ int error;
	+
	+ LLE_RLOCK(lle);
	+ error = dump_lle_locked(lle, arg);
	+ LLE_RUNLOCK(lle);
	+ return (error);
	+}
	+
	+static bool
	+dump_llt(struct lltable llt, struct netlink_walkargs wa)
	+{
	+ lltable_foreach_lle(llt, dump_lle, wa);
	+
	+ return (true);
	+}
	+
	+static int
	+dump_llts_iface(struct netlink_walkargs wa, struct ifnet ifp, int family)
	+{
	+ int error = 0;
	+
	+ wa->ifp = ifp;
	+ for (int i = 0; i < sizeof(lle_families) / sizeof(int); i++) {
	+ int fam = lle_families[i];
	+ struct lltable *llt = lltable_get(ifp, fam);
	+ if (llt != NULL && (family == 0 \|\| family == fam)) {
	+ wa->count++;
	+ wa->family = fam;
	+ if (!dump_llt(llt, wa)) {
	+ error = ENOMEM;
	+ break;
	+ }
	+ wa->dumped++;
	+ }
	+ }
	+ return (error);
	+}
	+
	+static int
	+dump_llts(struct netlink_walkargs wa, struct ifnet ifp, int family)
	+{
	+ NL_LOG(LOG_DEBUG, "Start dump ifp=%s family=%d", ifp ? if_name(ifp) : "NULL", family);
	+
	+ wa->hdr.nlmsg_flags \|= NLM_F_MULTI;
	+
	+ if (ifp != NULL) {
	+ dump_llts_iface(wa, ifp, family);
	+ } else {
	+ CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
	+ dump_llts_iface(wa, ifp, family);
	+ }
	+ }
	+
	+ NL_LOG(LOG_DEBUG, "End dump, iterated %d dumped %d", wa->count, wa->dumped);
	+
	+ if (!nlmsg_end_dump(wa->nw, wa->error, &wa->hdr)) {
	+ NL_LOG(LOG_DEBUG, "Unable to add new message");
	+ return (ENOMEM);
	+ }
	+
	+ return (0);
	+}
	+
	+static int
	+get_lle(struct netlink_walkargs wa, struct ifnet ifp, int family, struct sockaddr *dst)
	+{
	+ struct lltable *llt = lltable_get(ifp, family);
	+ if (llt == NULL)
	+ return (ESRCH);
	+
	+#ifdef INET6
	+ if (dst->sa_family == AF_INET6) {
	+ struct sockaddr_in6 dst6 = (struct sockaddr_in6 )dst;
	+
	+ if (IN6_IS_SCOPE_LINKLOCAL(&dst6->sin6_addr))
	+ in6_set_unicast_scopeid(&dst6->sin6_addr, ifp->if_index);
	+ }
	+#endif
	+ struct llentry *lle = lla_lookup(llt, LLE_UNLOCKED, dst);
	+ if (lle == NULL)
	+ return (ESRCH);
	+
	+ wa->ifp = ifp;
	+ wa->family = family;
	+
	+ return (dump_lle(llt, lle, wa));
	+}
	+
	+struct nl_parsed_neigh {
	+ struct sockaddr *nda_dst;
	+ struct ifnet *nda_ifp;
	+ struct nlattr *nda_lladdr;
	+ uint32_t ndm_flags;
	+ uint16_t ndm_state;
	+ uint8_t ndm_family;
	+};
	+
	+#define _IN(_field) offsetof(struct ndmsg, _field)
	+#define _OUT(_field) offsetof(struct nl_parsed_neigh, _field)
	+static struct nlfield_parser nlf_p_neigh[] = {
	+ { .off_in = _IN(ndm_family), .off_out = _OUT(ndm_family), .cb = nlf_get_u8 },
	+ { .off_in = _IN(ndm_flags), .off_out = _OUT(ndm_flags), .cb = nlf_get_u8_u32 },
	+ { .off_in = _IN(ndm_state), .off_out = _OUT(ndm_state), .cb = nlf_get_u16 },
	+ { .off_in = _IN(ndm_ifindex), .off_out = _OUT(nda_ifp), .cb = nlf_get_ifpz },
	+};
	+
	+static struct nlattr_parser nla_p_neigh[] = {
	+ { .type = NDA_DST, .off = _OUT(nda_dst), .cb = nlattr_get_ip },
	+ { .type = NDA_LLADDR, .off = _OUT(nda_lladdr), .cb = nlattr_get_nla },
	+ { .type = NDA_IFINDEX, .off = _OUT(nda_ifp), .cb = nlattr_get_ifp },
	+ { .type = NDA_FLAGS_EXT, .off = _OUT(ndm_flags), .cb = nlattr_get_uint32 },
	+};
	+#undef _IN
	+#undef _OUT
	+NL_DECLARE_PARSER(ndmsg_parser, struct ndmsg, nlf_p_neigh, nla_p_neigh);
	+
	+
	+/*
	+ * type=RTM_NEWNEIGH, flags=NLM_F_REQUEST\|NLM_F_ACK\|NLM_F_EXCL\|NLM_F_CREATE, seq=1661941473, pid=0},
	+ * {ndm_family=AF_INET6, ndm_ifindex=if_nametoindex("enp0s31f6"), ndm_state=NUD_PERMANENT, ndm_flags=0, ndm_type=RTN_UNSPEC},
	+ * [
	+ * {{nla_len=20, nla_type=NDA_DST}, inet_pton(AF_INET6, "2a01:4f8:13a:70c::3")},
	+ * {{nla_len=10, nla_type=NDA_LLADDR}, 20:4e:71:62:ae:f2}]}, iov_len=60}
	+ */
	+
	+static int
	+rtnl_handle_newneigh(struct nlmsghdr hdr, struct nlpcb nlp, struct nl_pstate *npt)
	+{
	+ int error;
	+
	+ struct nl_parsed_neigh attrs = {};
	+ error = nl_parse_nlmsg(hdr, &ndmsg_parser, npt, &attrs);
	+ if (error != 0)
	+ return (error);
	+
	+ if (attrs.nda_ifp == NULL \|\| attrs.nda_dst == NULL \|\| attrs.nda_lladdr == NULL) {
	+ if (attrs.nda_ifp == NULL)
	+ NLMSG_REPORT_ERR_MSG(npt, "NDA_IFINDEX / ndm_ifindex not set");
	+ if (attrs.nda_dst == NULL)
	+ NLMSG_REPORT_ERR_MSG(npt, "NDA_DST not set");
	+ if (attrs.nda_lladdr == NULL)
	+ NLMSG_REPORT_ERR_MSG(npt, "NDA_LLADDR not set");
	+ return (EINVAL);
	+ }
	+
	+ if (attrs.nda_dst->sa_family != attrs.ndm_family) {
	+ NLMSG_REPORT_ERR_MSG(npt,
	+ "NDA_DST family (%d) is different from ndm_family (%d)",
	+ attrs.nda_dst->sa_family, attrs.ndm_family);
	+ return (EINVAL);
	+ }
	+
	+ int addrlen = attrs.nda_ifp->if_addrlen;
	+ if (attrs.nda_lladdr->nla_len != sizeof(struct nlattr) + addrlen) {
	+ NLMSG_REPORT_ERR_MSG(npt,
	+ "NDA_LLADDR address length (%ld) is different from expected (%d)",
	+ attrs.nda_lladdr->nla_len - sizeof(struct nlattr), addrlen);
	+ return (EINVAL);
	+ }
	+
	+ if (attrs.ndm_state != NUD_PERMANENT) {
	+ NLMSG_REPORT_ERR_MSG(npt, "ndm_state %d not supported", attrs.ndm_state);
	+ return (ENOTSUP);
	+ }
	+
	+ const uint16_t supported_flags = NTF_PROXY \| NTF_STICKY;
	+ if ((attrs.ndm_flags & supported_flags) != attrs.ndm_flags) {
	+ NLMSG_REPORT_ERR_MSG(npt, "ndm_flags %X not supported",
	+ attrs.ndm_flags &~ supported_flags);
	+ return (ENOTSUP);
	+ }
	+
	+ /* Replacement requires new entry creation anyway */
	+ if ((hdr->nlmsg_flags & (NLM_F_CREATE \| NLM_F_REPLACE)) == 0)
	+ return (ENOTSUP);
	+
	+ struct lltable *llt = lltable_get(attrs.nda_ifp, attrs.ndm_family);
	+ if (llt == NULL)
	+ return (EAFNOSUPPORT);
	+
	+
	+ uint8_t linkhdr[LLE_MAX_LINKHDR];
	+ size_t linkhdrsize = sizeof(linkhdr);
	+ int lladdr_off = 0;
	+ if (lltable_calc_llheader(attrs.nda_ifp, attrs.ndm_family,
	+ (char *)(attrs.nda_lladdr + 1), linkhdr, &linkhdrsize, &lladdr_off) != 0) {
	+ NLMSG_REPORT_ERR_MSG(npt, "unable to calculate lle prepend data");
	+ return (EINVAL);
	+ }
	+
	+ int lle_flags = LLE_STATIC \| ((attrs.ndm_flags & NTF_PROXY) ? LLE_PUB : 0);
	+ struct llentry *lle = lltable_alloc_entry(llt, lle_flags, attrs.nda_dst);
	+ if (lle == NULL)
	+ return (ENOMEM);
	+ lltable_set_entry_addr(attrs.nda_ifp, lle, linkhdr, linkhdrsize, lladdr_off);
	+
	+ /* llentry created, try to insert or update :*/
	+ IF_AFDATA_WLOCK(attrs.nda_ifp);
	+ LLE_WLOCK(lle);
	+ struct llentry *lle_tmp = lla_lookup(llt, LLE_EXCLUSIVE, attrs.nda_dst);
	+ if (lle_tmp != NULL) {
	+ if (hdr->nlmsg_flags & NLM_F_EXCL) {
	+ LLE_WUNLOCK(lle_tmp);
	+ lle_tmp = NULL;
	+ error = EEXIST;
	+ } else if (hdr->nlmsg_flags & NLM_F_REPLACE) {
	+ lltable_unlink_entry(llt, lle_tmp);
	+ lltable_link_entry(llt, lle);
	+ } else
	+ error = EEXIST;
	+ } else {
	+ if (hdr->nlmsg_flags & NLM_F_CREATE)
	+ lltable_link_entry(llt, lle);
	+ else
	+ error = ENOENT;
	+ }
	+ IF_AFDATA_WUNLOCK(attrs.nda_ifp);
	+
	+ if (error != 0) {
	+ if (lle != NULL)
	+ llentry_free(lle);
	+ return (error);
	+ }
	+
	+ if (lle_tmp != NULL)
	+ llentry_free(lle_tmp);
	+
	+ /* XXX: We're inside epoch */
	+ EVENTHANDLER_INVOKE(lle_event, lle, LLENTRY_RESOLVED);
	+ LLE_WUNLOCK(lle);
	+
	+ return (0);
	+}
	+
	+static int
	+rtnl_handle_delneigh(struct nlmsghdr hdr, struct nlpcb nlp, struct nl_pstate *npt)
	+{
	+ int error;
	+
	+ struct nl_parsed_neigh attrs = {};
	+ error = nl_parse_nlmsg(hdr, &ndmsg_parser, npt, &attrs);
	+ if (error != 0)
	+ return (error);
	+
	+ if (attrs.nda_dst == NULL) {
	+ NLMSG_REPORT_ERR_MSG(npt, "NDA_DST not set");
	+ return (EINVAL);
	+ }
	+
	+ if (attrs.nda_ifp == NULL) {
	+ NLMSG_REPORT_ERR_MSG(npt, "no ifindex provided");
	+ return (EINVAL);
	+ }
	+
	+ struct lltable *llt = lltable_get(attrs.nda_ifp, attrs.ndm_family);
	+ if (llt == NULL)
	+ return (EAFNOSUPPORT);
	+
	+ IF_AFDATA_WLOCK(attrs.nda_ifp);
	+ struct llentry *lle = lla_lookup(llt, LLE_EXCLUSIVE, attrs.nda_dst);
	+ if (lle != NULL) {
	+ if ((lle->la_flags & LLE_IFADDR) != 0) {
	+ LLE_WUNLOCK(lle);
	+ lle = NULL;
	+ error = EPERM;
	+ } else
	+ lltable_unlink_entry(llt, lle);
	+ } else
	+ error = ENOENT;
	+ IF_AFDATA_WUNLOCK(attrs.nda_ifp);
	+
	+ if (error == 0 && lle != NULL)
	+ EVENTHANDLER_INVOKE(lle_event, lle, LLENTRY_DELETED);
	+
	+ if (lle != NULL)
	+ llentry_free(lle);
	+
	+ return (error);
	+}
	+
	+static int
	+rtnl_handle_getneigh(struct nlmsghdr hdr, struct nlpcb nlp, struct nl_pstate *npt)
	+{
	+ int error;
	+
	+ struct nl_parsed_neigh attrs = {};
	+ error = nl_parse_nlmsg(hdr, &ndmsg_parser, npt, &attrs);
	+ if (error != 0)
	+ return (error);
	+
	+ if (attrs.nda_dst != NULL && attrs.nda_ifp == NULL) {
	+ NLMSG_REPORT_ERR_MSG(npt, "has NDA_DST but no ifindex provided");
	+ return (EINVAL);
	+ }
	+
	+ struct netlink_walkargs wa = {
	+ .so = nlp,
	+ .nw = npt->nw,
	+ .hdr.nlmsg_pid = hdr->nlmsg_pid,
	+ .hdr.nlmsg_seq = hdr->nlmsg_seq,
	+ .hdr.nlmsg_flags = hdr->nlmsg_flags,
	+ .hdr.nlmsg_type = NL_RTM_NEWNEIGH,
	+ };
	+
	+ if (attrs.nda_dst == NULL)
	+ error = dump_llts(&wa, attrs.nda_ifp, attrs.ndm_family);
	+ else
	+ error = get_lle(&wa, attrs.nda_ifp, attrs.ndm_family, attrs.nda_dst);
	+
	+ return (error);
	+}
	+
	+static const struct rtnl_cmd_handler cmd_handlers[] = {
	+ {
	+ .cmd = NL_RTM_NEWNEIGH,
	+ .name = "RTM_NEWNEIGH",
	+ .cb = &rtnl_handle_newneigh,
	+ },
	+ {
	+ .cmd = NL_RTM_DELNEIGH,
	+ .name = "RTM_DELNEIGH",
	+ .cb = &rtnl_handle_delneigh,
	+ .priv = PRIV_NET_ROUTE,
	+ },
	+ {
	+ .cmd = NL_RTM_GETNEIGH,
	+ .name = "RTM_GETNEIGH",
	+ .cb = &rtnl_handle_getneigh,
	+ .priv = PRIV_NET_ROUTE,
	+ }
	+};
	+
	+static void
	+rtnl_lle_event(void arg __unused, struct llentry lle, int evt)
	+{
	+ struct ifnet *ifp;
	+ int family;
	+
	+ LLE_WLOCK_ASSERT(lle);
	+
	+ ifp = lltable_get_ifp(lle->lle_tbl);
	+ family = lltable_get_af(lle->lle_tbl);
	+
	+ if (family != AF_INET && family != AF_INET6)
	+ return;
	+
	+ int nlmsgs_type = evt == LLENTRY_RESOLVED ? NL_RTM_NEWNEIGH : NL_RTM_DELNEIGH;
	+
	+ struct nl_writer nw = {};
	+ if (!nlmsg_get_group_writer(&nw, NLMSG_SMALL, NETLINK_ROUTE, RTNLGRP_NEIGH)) {
	+ NL_LOG(LOG_DEBUG, "error allocating group writer");
	+ return;
	+ }
	+
	+ struct netlink_walkargs wa = {
	+ .hdr.nlmsg_type = nlmsgs_type,
	+ .nw = &nw,
	+ .ifp = ifp,
	+ .family = family,
	+ };
	+
	+ dump_lle_locked(lle, &wa);
	+ nlmsg_flush(&nw);
	+}
	+
	+static const struct nlhdr_parser *all_parsers[] = { &ndmsg_parser };
	+
	+void
	+rtnl_neighs_init()
	+{
	+ NL_VERIFY_PARSERS(all_parsers);
	+ rtnl_register_messages(cmd_handlers, NL_ARRAY_LEN(cmd_handlers));
	+ lle_event_p = EVENTHANDLER_REGISTER(lle_event, rtnl_lle_event, NULL,
	+ EVENTHANDLER_PRI_ANY);
	+}
	+
	+void
	+rtnl_neighs_destroy()
	+{
	+ EVENTHANDLER_DEREGISTER(lle_event, lle_event_p);
	+}
	diff --git a/sys/netlink/route/nexthop.h b/sys/netlink/route/nexthop.h
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/route/nexthop.h
	@@ -0,0 +1,102 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+/*
	+ * NEXTHOP-related (RTM_<NEW\|DEL\|GET>NEXTHOP) message header and attributes.
	+ */
	+
	+#ifndef _NETLINK_ROUTE_NEXTHOP_H_
	+#define _NETLINK_ROUTE_NEXTHOP_H_
	+
	+/* Base header for all of the relevant messages */
	+struct nhmsg {
	+ unsigned char nh_family; /* transport family */
	+ unsigned char nh_scope; /* ignored on RX, filled by kernel */
	+ unsigned char nh_protocol; /* Routing protocol that installed nh */
	+ unsigned char resvd;
	+ unsigned int nh_flags; /* RTNH_F_* flags from route.h */
	+};
	+
	+enum {
	+ NHA_UNSPEC,
	+ NHA_ID, /* u32: nexthop userland index, auto-assigned if 0 */
	+ NHA_GROUP, /* binary: array of struct nexthop_grp */
	+ NHA_GROUP_TYPE, /* u16: set to NEXTHOP_GRP_TYPE */
	+ NHA_BLACKHOLE, /* flag: nexthop used to blackhole packets */
	+ NHA_OIF, /* u32: transmit ifindex */
	+ NHA_GATEWAY, /* network: IPv4/IPv6 gateway addr */
	+ NHA_ENCAP_TYPE, /* not supported */
	+ NHA_ENCAP, /* not supported */
	+ NHA_GROUPS, /* flag: match nexthop groups */
	+ NHA_MASTER, /* not supported */
	+ NHA_FDB, /* not supported */
	+ NHA_RES_GROUP, /* not supported */
	+ NHA_RES_BUCKET, /* not supported */
	+ __NHA_MAX,
	+};
	+#define NHA_MAX (__NHA_MAX - 1)
	+
	+/*
	+ * Attributes that can be used as filters:
	+ * NHA_ID (nexhop or group), NHA_OIF, NHA_GROUPS,
	+ */
	+
	+/*
	+ * NHA_GROUP: array of the following structures.
	+ * If attribute is set, the only other valid attributes are
	+ * NHA_ID and NHA_GROUP_TYPE.
	+ * NHA_RES_GROUP and NHA_RES_BUCKET are not supported yet
	+ */
	+struct nexthop_grp {
	+ uint32_t id; /* nexhop userland index */
	+ uint8_t weight; /* weight of this nexthop */
	+ uint8_t resvd1;
	+ uint16_t resvd2;
	+};
	+
	+/* NHA_GROUP_TYPE: u16 */
	+enum {
	+ NEXTHOP_GRP_TYPE_MPATH, /* default nexthop group */
	+ NEXTHOP_GRP_TYPE_RES, /* resilient nexthop group */
	+ __NEXTHOP_GRP_TYPE_MAX,
	+};
	+#define NEXTHOP_GRP_TYPE_MAX (__NEXTHOP_GRP_TYPE_MAX - 1)
	+
	+
	+/* NHA_RES_GROUP */
	+enum {
	+ NHA_RES_GROUP_UNSPEC,
	+ NHA_RES_GROUP_PAD = NHA_RES_GROUP_UNSPEC,
	+ NHA_RES_GROUP_BUCKETS,
	+ NHA_RES_GROUP_IDLE_TIMER,
	+ NHA_RES_GROUP_UNBALANCED_TIMER,
	+ NHA_RES_GROUP_UNBALANCED_TIME,
	+ __NHA_RES_GROUP_MAX,
	+};
	+#define NHA_RES_GROUP_MAX (__NHA_RES_GROUP_MAX - 1)
	+
	+#endif
	diff --git a/sys/netlink/route/nexthop.c b/sys/netlink/route/nexthop.c
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/route/nexthop.c
	@@ -0,0 +1,1000 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+#include <sys/cdefs.h>
	+__FBSDID("$FreeBSD$");
	+#include "opt_inet.h"
	+#include "opt_inet6.h"
	+#include <sys/types.h>
	+#include <sys/malloc.h>
	+#include <sys/rmlock.h>
	+#include <sys/socket.h>
	+#include <sys/ck.h>
	+
	+#include <net/if.h>
	+#include <net/route.h>
	+#include <net/route/nhop.h>
	+#include <net/route/nhop_utils.h>
	+
	+#include <net/route/route_ctl.h>
	+#include <net/route/route_var.h>
	+#include <netinet6/scope6_var.h>
	+#include <netlink/netlink.h>
	+#include <netlink/netlink_ctl.h>
	+#include <netlink/netlink_var.h>
	+#include <netlink/netlink_route.h>
	+#include <netlink/route/route_var.h>
	+
	+#define DEBUG_MOD_NAME nl_nhop
	+#define DEBUG_MAX_LEVEL LOG_DEBUG3
	+#include <netlink/netlink_debug.h>
	+_DECLARE_DEBUG(LOG_DEBUG3);
	+
	+/*
	+ * This file contains the logic to maintain kernel nexthops and
	+ * nexhop groups based om the data provided by the user.
	+ *
	+ * Kernel stores (nearly) all of the routing data in the nexthops,
	+ * including the prefix-specific flags (NHF_HOST and NHF_DEFAULT).
	+ *
	+ * Netlink API provides higher-level abstraction for the user. Each
	+ * user-created nexthop may map to multiple kernel nexthops.
	+ *
	+ * The following variations require separate kernel nexthop to be
	+ * created:
	+ * * prefix flags (NHF_HOST, NHF_DEFAULT)
	+ * * using IPv6 gateway for IPv4 routes
	+ * * different fibnum
	+ *
	+ * These kernel nexthops have the lifetime bound to the lifetime of
	+ * the user_nhop object. They are not collected until user requests
	+ * to delete the created user_nhop.
	+ *
	+ */
	+struct user_nhop {
	+ uint32_t un_idx; /* Userland-provided index */
	+ uint32_t un_fibfam; /* fibnum+af(as highest byte) */
	+ uint8_t un_protocol; /* protocol that install the record */
	+ struct nhop_object un_nhop; / "production" nexthop */
	+ struct nhop_object un_nhop_src; / nexthop to copy from */
	+ struct weightened_nhop un_nhgrp_src; / nexthops for nhg */
	+ uint32_t un_nhgrp_count; /* number of nexthops */
	+ struct user_nhop un_next; / next item in hash chain */
	+ struct user_nhop un_nextchild; / master -> children */
	+ struct epoch_context un_epoch_ctx; /* epoch ctl helper */
	+};
	+
	+/* produce hash value for an object */
	+#define unhop_hash_obj(_obj) (hash_unhop(_obj))
	+/* compare two objects */
	+#define unhop_cmp(_one, _two) (cmp_unhop(_one, _two))
	+/* next object accessor */
	+#define unhop_next(_obj) (_obj)->un_next
	+
	+CHT_SLIST_DEFINE(unhop, struct user_nhop);
	+
	+struct unhop_ctl {
	+ struct unhop_head un_head;
	+ struct rmlock un_lock;
	+};
	+#define UN_LOCK_INIT(_ctl) rm_init(&(_ctl)->un_lock, "unhop_ctl")
	+#define UN_TRACKER struct rm_priotracker un_tracker
	+#define UN_RLOCK(_ctl) rm_rlock(&((_ctl)->un_lock), &un_tracker)
	+#define UN_RUNLOCK(_ctl) rm_runlock(&((_ctl)->un_lock), &un_tracker)
	+
	+#define UN_WLOCK(_ctl) rm_wlock(&(_ctl)->un_lock);
	+#define UN_WUNLOCK(_ctl) rm_wunlock(&(_ctl)->un_lock);
	+
	+VNET_DEFINE_STATIC(struct unhop_ctl *, un_ctl) = NULL;
	+#define V_un_ctl VNET(un_ctl)
	+
	+static void consider_resize(struct unhop_ctl *ctl, uint32_t new_size);
	+static int cmp_unhop(const struct user_nhop a, const struct user_nhop b);
	+static unsigned int hash_unhop(const struct user_nhop *obj);
	+
	+static void destroy_unhop(struct user_nhop *unhop);
	+static struct nhop_object clone_unhop(const struct user_nhop unhop,
	+ uint32_t fibnum, int family, int nh_flags);
	+
	+static int
	+cmp_unhop(const struct user_nhop a, const struct user_nhop b)
	+{
	+ return (a->un_idx == b->un_idx && a->un_fibfam == b->un_fibfam);
	+}
	+
	+/*
	+ * Hash callback: calculate hash of an object
	+ */
	+static unsigned int
	+hash_unhop(const struct user_nhop *obj)
	+{
	+ return (obj->un_idx ^ obj->un_fibfam);
	+}
	+
	+#define UNHOP_IS_MASTER(_unhop) ((_unhop)->un_fibfam == 0)
	+
	+/*
	+ * Factory interface for creating matching kernel nexthops/nexthop groups
	+ *
	+ * @uidx: userland nexhop index used to create the nexthop
	+ * @fibnum: fibnum nexthop will be used in
	+ * @family: upper family nexthop will be used in
	+ * @nh_flags: desired nexthop prefix flags
	+ * @perror: pointer to store error to
	+ *
	+ * Returns referenced nexthop linked to @fibnum/@family rib on success.
	+ */
	+struct nhop_object *
	+nl_find_nhop(uint32_t fibnum, int family, uint32_t uidx,
	+ int nh_flags, int *perror)
	+{
	+ struct unhop_ctl *ctl = atomic_load_ptr(&V_un_ctl);
	+ UN_TRACKER;
	+
	+ if (__predict_false(ctl == NULL))
	+ return (NULL);
	+
	+ struct user_nhop key= {
	+ .un_idx = uidx,
	+ .un_fibfam = fibnum \| ((uint32_t)family) << 24,
	+ };
	+ struct user_nhop *unhop;
	+
	+ nh_flags = nh_flags & (NHF_HOST \| NHF_DEFAULT);
	+
	+ if (__predict_false(family == 0))
	+ return (NULL);
	+
	+ UN_RLOCK(ctl);
	+ CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, &key, unhop);
	+ if (unhop != NULL) {
	+ struct nhop_object *nh = unhop->un_nhop;
	+ UN_RLOCK(ctl);
	+ *perror = 0;
	+ nhop_ref_any(nh);
	+ return (nh);
	+ }
	+
	+ /*
	+ * Exact nexthop not found. Search for template nexthop to clone from.
	+ */
	+ key.un_fibfam = 0;
	+ CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, &key, unhop);
	+ if (unhop == NULL) {
	+ UN_RUNLOCK(ctl);
	+ *perror = ESRCH;
	+ return (NULL);
	+ }
	+
	+ UN_RUNLOCK(ctl);
	+
	+ /* Create entry to insert first */
	+ struct user_nhop un_new, un_tmp;
	+ un_new = malloc(sizeof(struct user_nhop), M_NETLINK, M_NOWAIT \| M_ZERO);
	+ if (un_new == NULL) {
	+ *perror = ENOMEM;
	+ return (NULL);
	+ }
	+ un_new->un_idx = uidx;
	+ un_new->un_fibfam = fibnum \| ((uint32_t)family) << 24;
	+
	+ /* Relying on epoch to protect unhop here */
	+ un_new->un_nhop = clone_unhop(unhop, fibnum, family, nh_flags);
	+ if (un_new->un_nhop == NULL) {
	+ free(un_new, M_NETLINK);
	+ *perror = ENOMEM;
	+ return (NULL);
	+ }
	+
	+ /* Insert back and report */
	+ UN_WLOCK(ctl);
	+
	+ /* First, find template record once again */
	+ CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, &key, unhop);
	+ if (unhop == NULL) {
	+ /* Someone deleted the nexthop during the call */
	+ UN_WUNLOCK(ctl);
	+ *perror = ESRCH;
	+ destroy_unhop(un_new);
	+ return (NULL);
	+ }
	+
	+ /* Second, check the direct match */
	+ CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, un_new, un_tmp);
	+ struct nhop_object *nh;
	+ if (un_tmp != NULL) {
	+ /* Another thread already created the desired nextop, use it */
	+ nh = un_tmp->un_nhop;
	+ } else {
	+ /* Finally, insert the new nexthop and link it to the primary */
	+ nh = un_new->un_nhop;
	+ CHT_SLIST_INSERT_HEAD(&ctl->un_head, unhop, un_new);
	+ un_new->un_nextchild = unhop->un_nextchild;
	+ unhop->un_nextchild = un_new;
	+ un_new = NULL;
	+ NL_LOG(LOG_DEBUG2, "linked cloned nexthop %p", nh);
	+ }
	+
	+ UN_WUNLOCK(ctl);
	+
	+ if (un_new != NULL)
	+ destroy_unhop(un_new);
	+
	+ *perror = 0;
	+ nhop_ref_any(nh);
	+ return (nh);
	+}
	+
	+static struct user_nhop *
	+nl_find_base_unhop(struct unhop_ctl *ctl, uint32_t uidx)
	+{
	+ struct user_nhop key= { .un_idx = uidx };
	+ struct user_nhop *unhop = NULL;
	+ UN_TRACKER;
	+
	+ UN_RLOCK(ctl);
	+ CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, &key, unhop);
	+ UN_RUNLOCK(ctl);
	+
	+ return (unhop);
	+}
	+
	+#define MAX_STACK_NHOPS 4
	+static struct nhop_object *
	+clone_unhop(const struct user_nhop *unhop, uint32_t fibnum, int family, int nh_flags)
	+{
	+ const struct weightened_nhop *wn;
	+ struct weightened_nhop *wn_new, wn_base[MAX_STACK_NHOPS];
	+ struct nhop_object *nh = NULL;
	+ uint32_t num_nhops;
	+ int error;
	+
	+ if (unhop->un_nhop_src != NULL) {
	+ IF_DEBUG_LEVEL(LOG_DEBUG2) {
	+ char nhbuf[NHOP_PRINT_BUFSIZE];
	+ nhop_print_buf_any(unhop->un_nhop_src, nhbuf, sizeof(nhbuf));
	+ FIB_NH_LOG(LOG_DEBUG2, unhop->un_nhop_src,
	+ "cloning nhop %s -> %u.%u flags 0x%X", nhbuf, fibnum,
	+ family, nh_flags);
	+ }
	+ struct nhop_object *nh;
	+ nh = nhop_alloc(fibnum, AF_UNSPEC);
	+ if (nh == NULL)
	+ return (NULL);
	+ nhop_copy(nh, unhop->un_nhop_src);
	+ /* Check that nexthop gateway is compatible with the new family */
	+ if (!nhop_set_upper_family(nh, family)) {
	+ nhop_free(nh);
	+ return (NULL);
	+ }
	+ nhop_set_uidx(nh, unhop->un_idx);
	+ nhop_set_pxtype_flag(nh, nh_flags);
	+ return (nhop_get_nhop(nh, &error));
	+ }
	+
	+ wn = unhop->un_nhgrp_src;
	+ num_nhops = unhop->un_nhgrp_count;
	+
	+ if (num_nhops > MAX_STACK_NHOPS) {
	+ wn_new = malloc(num_nhops * sizeof(struct weightened_nhop), M_TEMP, M_NOWAIT);
	+ if (wn_new == NULL)
	+ return (NULL);
	+ } else
	+ wn_new = wn_base;
	+
	+ for (int i = 0; i < num_nhops; i++) {
	+ uint32_t uidx = nhop_get_uidx(wn[i].nh);
	+ MPASS(uidx != 0);
	+ wn_new[i].nh = nl_find_nhop(fibnum, family, uidx, nh_flags, &error);
	+ if (error != 0)
	+ break;
	+ wn_new[i].weight = wn[i].weight;
	+ }
	+
	+ if (error == 0) {
	+ struct rib_head *rh = nhop_get_rh(wn_new[0].nh);
	+ struct nhgrp_object *nhg;
	+
	+ error = nhgrp_get_group(rh, wn_new, num_nhops, unhop->un_idx, &nhg);
	+ nh = (struct nhop_object *)nhg;
	+ }
	+
	+ if (wn_new != wn_base)
	+ free(wn_new, M_TEMP);
	+ return (nh);
	+}
	+
	+static void
	+destroy_unhop(struct user_nhop *unhop)
	+{
	+ if (unhop->un_nhop != NULL)
	+ nhop_free_any(unhop->un_nhop);
	+ if (unhop->un_nhop_src != NULL)
	+ nhop_free_any(unhop->un_nhop_src);
	+ free(unhop, M_NETLINK);
	+}
	+
	+static void
	+destroy_unhop_epoch(epoch_context_t ctx)
	+{
	+ struct user_nhop *unhop;
	+
	+ unhop = __containerof(ctx, struct user_nhop, un_epoch_ctx);
	+
	+ destroy_unhop(unhop);
	+}
	+
	+static uint32_t
	+find_spare_uidx(struct unhop_ctl *ctl)
	+{
	+ struct user_nhop *unhop, key = {};
	+ uint32_t uidx = 0;
	+ UN_TRACKER;
	+
	+ UN_RLOCK(ctl);
	+ /* This should return spare uid with 75% of 65k used in ~99/100 cases */
	+ for (int i = 0; i < 16; i++) {
	+ key.un_idx = (arc4random() % 65536) + 65536 * 4;
	+ CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, &key, unhop);
	+ if (unhop == NULL) {
	+ uidx = key.un_idx;
	+ break;
	+ }
	+ }
	+ UN_RUNLOCK(ctl);
	+
	+ return (uidx);
	+}
	+
	+
	+/*
	+ * Actual netlink code
	+ */
	+struct netlink_walkargs {
	+ struct nl_writer *nw;
	+ struct nlmsghdr hdr;
	+ struct nlpcb *so;
	+ int family;
	+ int error;
	+ int count;
	+ int dumped;
	+};
	+#define ENOMEM_IF_NULL(_v) if ((_v) == NULL) goto enomem
	+
	+static bool
	+dump_nhgrp(const struct user_nhop unhop, struct nlmsghdr hdr,
	+ struct nl_writer *nw)
	+{
	+
	+ if (!nlmsg_reply(nw, hdr, sizeof(struct nhmsg)))
	+ goto enomem;
	+
	+ struct nhmsg *nhm = nlmsg_reserve_object(nw, struct nhmsg);
	+ nhm->nh_family = AF_UNSPEC;
	+ nhm->nh_scope = 0;
	+ nhm->nh_protocol = unhop->un_protocol;
	+ nhm->nh_flags = 0;
	+
	+ nlattr_add_u32(nw, NHA_ID, unhop->un_idx);
	+ nlattr_add_u16(nw, NHA_GROUP_TYPE, NEXTHOP_GRP_TYPE_MPATH);
	+
	+ struct weightened_nhop *wn = unhop->un_nhgrp_src;
	+ uint32_t num_nhops = unhop->un_nhgrp_count;
	+ /* TODO: a better API? */
	+ int nla_len = sizeof(struct nlattr);
	+ nla_len += NETLINK_ALIGN(num_nhops * sizeof(struct nexthop_grp));
	+ struct nlattr *nla = nlmsg_reserve_data(nw, nla_len, struct nlattr);
	+ if (nla == NULL)
	+ goto enomem;
	+ nla->nla_type = NHA_GROUP;
	+ nla->nla_len = nla_len;
	+ for (int i = 0; i < num_nhops; i++) {
	+ struct nexthop_grp grp = &((struct nexthop_grp )(nla + 1))[i];
	+ grp->id = nhop_get_uidx(wn[i].nh);
	+ grp->weight = wn[i].weight;
	+ grp->resvd1 = 0;
	+ grp->resvd2 = 0;
	+ }
	+
	+ if (nlmsg_end(nw))
	+ return (true);
	+enomem:
	+ NL_LOG(LOG_DEBUG, "error: unable to allocate attribute memory");
	+ nlmsg_abort(nw);
	+ return (false);
	+}
	+
	+static bool
	+dump_nhop(const struct user_nhop unhop, struct nlmsghdr hdr,
	+ struct nl_writer *nw)
	+{
	+ struct nhop_object *nh = unhop->un_nhop_src;
	+
	+ if (!nlmsg_reply(nw, hdr, sizeof(struct nhmsg)))
	+ goto enomem;
	+
	+ struct nhmsg *nhm = nlmsg_reserve_object(nw, struct nhmsg);
	+ ENOMEM_IF_NULL(nhm);
	+ nhm->nh_family = nhop_get_neigh_family(nh);
	+ nhm->nh_scope = 0; // XXX: what's that?
	+ nhm->nh_protocol = unhop->un_protocol;
	+ nhm->nh_flags = 0;
	+
	+ nlattr_add_u32(nw, NHA_ID, unhop->un_idx);
	+ if (nh->nh_flags & NHF_BLACKHOLE) {
	+ nlattr_add_flag(nw, NHA_BLACKHOLE);
	+ goto done;
	+ }
	+ nlattr_add_u32(nw, NHA_OIF, nh->nh_ifp->if_index);
	+
	+ switch (nh->gw_sa.sa_family) {
	+#ifdef INET
	+ case AF_INET:
	+ nlattr_add(nw, NHA_GATEWAY, 4, &nh->gw4_sa.sin_addr);
	+ break;
	+#endif
	+#ifdef INET6
	+ case AF_INET6:
	+ {
	+ struct in6_addr addr = nh->gw6_sa.sin6_addr;
	+ in6_clearscope(&addr);
	+ nlattr_add(nw, NHA_GATEWAY, 16, &addr);
	+ break;
	+ }
	+#endif
	+ }
	+
	+done:
	+ if (nlmsg_end(nw))
	+ return (true);
	+enomem:
	+ nlmsg_abort(nw);
	+ return (false);
	+}
	+
	+static void
	+dump_unhop(const struct user_nhop unhop, struct nlmsghdr hdr,
	+ struct nl_writer *nw)
	+{
	+ if (unhop->un_nhop_src != NULL)
	+ dump_nhop(unhop, hdr, nw);
	+ else
	+ dump_nhgrp(unhop, hdr, nw);
	+}
	+
	+static int
	+delete_unhop(struct unhop_ctl ctl, struct nlmsghdr hdr, uint32_t uidx)
	+{
	+ struct user_nhop unhop_ret, unhop_base, *unhop_chain;
	+
	+ struct user_nhop key = { .un_idx = uidx };
	+
	+ UN_WLOCK(ctl);
	+
	+ CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, &key, unhop_base);
	+
	+ if (unhop_base != NULL) {
	+ CHT_SLIST_REMOVE(&ctl->un_head, unhop, unhop_base, unhop_ret);
	+ IF_DEBUG_LEVEL(LOG_DEBUG2) {
	+ char nhbuf[NHOP_PRINT_BUFSIZE];
	+ nhop_print_buf_any(unhop_base->un_nhop, nhbuf, sizeof(nhbuf));
	+ FIB_NH_LOG(LOG_DEBUG3, unhop_base->un_nhop,
	+ "removed base nhop %u: %s", uidx, nhbuf);
	+ }
	+ /* Unlink all child nexhops as well, keeping the chain intact */
	+ unhop_chain = unhop_base->un_nextchild;
	+ while (unhop_chain != NULL) {
	+ CHT_SLIST_REMOVE(&ctl->un_head, unhop, unhop_chain,
	+ unhop_ret);
	+ MPASS(unhop_chain == unhop_ret);
	+ IF_DEBUG_LEVEL(LOG_DEBUG3) {
	+ char nhbuf[NHOP_PRINT_BUFSIZE];
	+ nhop_print_buf_any(unhop_chain->un_nhop,
	+ nhbuf, sizeof(nhbuf));
	+ FIB_NH_LOG(LOG_DEBUG3, unhop_chain->un_nhop,
	+ "removed child nhop %u: %s", uidx, nhbuf);
	+ }
	+ unhop_chain = unhop_chain->un_nextchild;
	+ }
	+ }
	+
	+ UN_WUNLOCK(ctl);
	+
	+ if (unhop_base == NULL) {
	+ NL_LOG(LOG_DEBUG, "unable to find unhop %u", uidx);
	+ return (ENOENT);
	+ }
	+
	+ /* Report nexthop deletion */
	+ struct netlink_walkargs wa = {
	+ .hdr.nlmsg_pid = hdr->nlmsg_pid,
	+ .hdr.nlmsg_seq = hdr->nlmsg_seq,
	+ .hdr.nlmsg_flags = hdr->nlmsg_flags,
	+ .hdr.nlmsg_type = NL_RTM_DELNEXTHOP,
	+ };
	+
	+ struct nl_writer nw = {};
	+ if (!nlmsg_get_group_writer(&nw, NLMSG_SMALL, NETLINK_ROUTE, RTNLGRP_NEXTHOP)) {
	+ NL_LOG(LOG_DEBUG, "error allocating message writer");
	+ return (ENOMEM);
	+ }
	+
	+ dump_unhop(unhop_base, &wa.hdr, &nw);
	+ nlmsg_flush(&nw);
	+
	+ while (unhop_base != NULL) {
	+ unhop_chain = unhop_base->un_nextchild;
	+ epoch_call(net_epoch_preempt, destroy_unhop_epoch,
	+ &unhop_base->un_epoch_ctx);
	+ unhop_base = unhop_chain;
	+ }
	+
	+ return (0);
	+}
	+
	+static void
	+consider_resize(struct unhop_ctl *ctl, uint32_t new_size)
	+{
	+ void *new_ptr = NULL;
	+ size_t alloc_size;
	+
	+ if (new_size == 0)
	+ return;
	+
	+ if (new_size != 0) {
	+ alloc_size = CHT_SLIST_GET_RESIZE_SIZE(new_size);
	+ new_ptr = malloc(alloc_size, M_NETLINK, M_NOWAIT \| M_ZERO);
	+ if (new_ptr == NULL)
	+ return;
	+ }
	+
	+ NL_LOG(LOG_DEBUG, "resizing hash: %u -> %u", ctl->un_head.hash_size, new_size);
	+ UN_WLOCK(ctl);
	+ if (new_ptr != NULL) {
	+ CHT_SLIST_RESIZE(&ctl->un_head, unhop, new_ptr, new_size);
	+ }
	+ UN_WUNLOCK(ctl);
	+
	+
	+ if (new_ptr != NULL)
	+ free(new_ptr, M_NETLINK);
	+}
	+
	+static bool __noinline
	+vnet_init_unhops()
	+{
	+ uint32_t num_buckets = 16;
	+ size_t alloc_size = CHT_SLIST_GET_RESIZE_SIZE(num_buckets);
	+
	+ struct unhop_ctl *ctl = malloc(sizeof(struct unhop_ctl), M_NETLINK,
	+ M_NOWAIT \| M_ZERO);
	+ if (ctl == NULL)
	+ return (false);
	+
	+ void *ptr = malloc(alloc_size, M_NETLINK, M_NOWAIT \| M_ZERO);
	+ if (ptr == NULL) {
	+ free(ctl, M_NETLINK);
	+ return (false);
	+ }
	+ CHT_SLIST_INIT(&ctl->un_head, ptr, num_buckets);
	+ UN_LOCK_INIT(ctl);
	+
	+ if (!atomic_cmpset_ptr((uintptr_t *)&V_un_ctl, (uintptr_t)NULL, (uintptr_t)ctl)) {
	+ free(ptr, M_NETLINK);
	+ free(ctl, M_NETLINK);
	+ }
	+
	+ if (atomic_load_ptr(&V_un_ctl) == NULL)
	+ return (false);
	+
	+ NL_LOG(LOG_NOTICE, "UNHOPS init done");
	+
	+ return (true);
	+}
	+
	+static void
	+vnet_destroy_unhops(const void *unused __unused)
	+{
	+ struct unhop_ctl *ctl = atomic_load_ptr(&V_un_ctl);
	+ struct user_nhop unhop, tmp;
	+
	+ if (ctl == NULL)
	+ return;
	+ V_un_ctl = NULL;
	+
	+ /* Wait till all unhop users finish their reads */
	+ epoch_wait_preempt(net_epoch_preempt);
	+
	+ UN_WLOCK(ctl);
	+ CHT_SLIST_FOREACH_SAFE(&ctl->un_head, unhop, unhop, tmp) {
	+ destroy_unhop(unhop);
	+ } CHT_SLIST_FOREACH_SAFE_END;
	+ UN_WUNLOCK(ctl);
	+
	+ free(ctl->un_head.ptr, M_NETLINK);
	+ free(ctl, M_NETLINK);
	+}
	+VNET_SYSUNINIT(vnet_destroy_unhops, SI_SUB_PROTO_IF, SI_ORDER_ANY,
	+ vnet_destroy_unhops, NULL);
	+
	+static int
	+nlattr_get_nhg(struct nlattr nla, struct nl_pstate npt, const void arg, void target)
	+{
	+ int error = 0;
	+
	+ /* Verify attribute correctness */
	+ struct nexthop_grp *grp = NLA_DATA(nla);
	+ int data_len = NLA_DATA_LEN(nla);
	+
	+ int count = data_len / sizeof(*grp);
	+ if (count == 0 \|\| (count * sizeof(*grp) != data_len)) {
	+ NL_LOG(LOG_DEBUG, "Invalid length for RTA_GROUP: %d", data_len);
	+ return (EINVAL);
	+ }
	+
	+ ((struct nlattr *)target) = nla;
	+ return (error);
	+}
	+
	+struct nl_parsed_nhop {
	+ uint32_t nha_id;
	+ uint8_t nha_blackhole;
	+ uint8_t nha_groups;
	+ struct ifnet *nha_oif;
	+ struct sockaddr *nha_gw;
	+ struct nlattr *nha_group;
	+ uint8_t nh_family;
	+ uint8_t nh_protocol;
	+};
	+
	+#define _IN(_field) offsetof(struct nhmsg, _field)
	+#define _OUT(_field) offsetof(struct nl_parsed_nhop, _field)
	+static const struct nlfield_parser nlf_p_nh[] = {
	+ { .off_in = _IN(nh_family), .off_out = _OUT(nh_family), .cb = nlf_get_u8 },
	+ { .off_in = _IN(nh_protocol), .off_out = _OUT(nh_protocol), .cb = nlf_get_u8 },
	+};
	+
	+static const struct nlattr_parser nla_p_nh[] = {
	+ { .type = NHA_ID, .off = _OUT(nha_id), .cb = nlattr_get_uint32 },
	+ { .type = NHA_GROUP, .off = _OUT(nha_group), .cb = nlattr_get_nhg },
	+ { .type = NHA_BLACKHOLE, .off = _OUT(nha_blackhole), .cb = nlattr_get_flag },
	+ { .type = NHA_OIF, .off = _OUT(nha_oif), .cb = nlattr_get_ifp },
	+ { .type = NHA_GATEWAY, .off = _OUT(nha_gw), .cb = nlattr_get_ip },
	+ { .type = NHA_GROUPS, .off = _OUT(nha_groups), .cb = nlattr_get_flag },
	+};
	+#undef _IN
	+#undef _OUT
	+NL_DECLARE_PARSER(nhmsg_parser, struct nhmsg, nlf_p_nh, nla_p_nh);
	+
	+static bool
	+eligible_nhg(const struct nhop_object *nh)
	+{
	+ return (nh->nh_flags & NHF_GATEWAY);
	+}
	+
	+static int
	+newnhg(struct unhop_ctl ctl, struct nl_parsed_nhop attrs, struct user_nhop *unhop)
	+{
	+ struct nexthop_grp *grp = NLA_DATA(attrs->nha_group);
	+ int count = NLA_DATA_LEN(attrs->nha_group) / sizeof(*grp);
	+ struct weightened_nhop *wn;
	+
	+ wn = malloc(sizeof(wn) count, M_NETLINK, M_NOWAIT \| M_ZERO);
	+ if (wn == NULL)
	+ return (ENOMEM);
	+
	+ for (int i = 0; i < count; i++) {
	+ struct user_nhop *unhop;
	+ unhop = nl_find_base_unhop(ctl, grp[i].id);
	+ if (unhop == NULL) {
	+ NL_LOG(LOG_DEBUG, "unable to find uidx %u", grp[i].id);
	+ free(wn, M_NETLINK);
	+ return (ESRCH);
	+ } else if (unhop->un_nhop_src == NULL) {
	+ NL_LOG(LOG_DEBUG, "uidx %u is a group, nested group unsupported",
	+ grp[i].id);
	+ free(wn, M_NETLINK);
	+ return (ENOTSUP);
	+ } else if (!eligible_nhg(unhop->un_nhop_src)) {
	+ NL_LOG(LOG_DEBUG, "uidx %u nhop is not mpath-eligible",
	+ grp[i].id);
	+ free(wn, M_NETLINK);
	+ return (ENOTSUP);
	+ }
	+ /*
	+ * TODO: consider more rigid eligibility checks:
	+ * restrict nexthops with the same gateway
	+ */
	+ wn[i].nh = unhop->un_nhop_src;
	+ wn[i].weight = grp[i].weight;
	+ }
	+ unhop->un_nhgrp_src = wn;
	+ unhop->un_nhgrp_count = count;
	+ return (0);
	+}
	+
	+static int
	+newnhop(struct nl_parsed_nhop attrs, struct user_nhop unhop)
	+{
	+ struct ifaddr *ifa = NULL;
	+ struct nhop_object *nh;
	+ int error;
	+
	+ if (!attrs->nha_blackhole) {
	+ if (attrs->nha_gw == NULL) {
	+ NL_LOG(LOG_DEBUG, "missing NHA_GATEWAY");
	+ return (EINVAL);
	+ }
	+ if (attrs->nha_oif == NULL) {
	+ NL_LOG(LOG_DEBUG, "missing NHA_OIF");
	+ return (EINVAL);
	+ }
	+ if (ifa == NULL)
	+ ifa = ifaof_ifpforaddr(attrs->nha_gw, attrs->nha_oif);
	+ if (ifa == NULL) {
	+ NL_LOG(LOG_DEBUG, "Unable to determine default source IP");
	+ return (EINVAL);
	+ }
	+ }
	+
	+ int family = attrs->nha_gw != NULL ? attrs->nha_gw->sa_family : attrs->nh_family;
	+
	+ nh = nhop_alloc(RT_DEFAULT_FIB, family);
	+ if (nh == NULL) {
	+ NL_LOG(LOG_DEBUG, "Unable to allocate nexthop");
	+ return (ENOMEM);
	+ }
	+ nhop_set_uidx(nh, attrs->nha_id);
	+
	+ if (attrs->nha_blackhole)
	+ nhop_set_blackhole(nh, NHF_BLACKHOLE);
	+ else {
	+ nhop_set_gw(nh, attrs->nha_gw, true);
	+ nhop_set_transmit_ifp(nh, attrs->nha_oif);
	+ nhop_set_src(nh, ifa);
	+ }
	+
	+ error = nhop_get_unlinked(nh);
	+ if (error != 0) {
	+ NL_LOG(LOG_DEBUG, "unable to finalize nexthop");
	+ return (error);
	+ }
	+
	+ IF_DEBUG_LEVEL(LOG_DEBUG2) {
	+ char nhbuf[NHOP_PRINT_BUFSIZE];
	+ nhop_print_buf(nh, nhbuf, sizeof(nhbuf));
	+ NL_LOG(LOG_DEBUG2, "Adding unhop %u: %s", attrs->nha_id, nhbuf);
	+ }
	+
	+ unhop->un_nhop_src = nh;
	+ return (0);
	+}
	+
	+static int
	+rtnl_handle_newnhop(struct nlmsghdr hdr, struct nlpcb nlp,
	+ struct nl_pstate *npt)
	+{
	+ struct user_nhop *unhop;
	+ int error;
	+
	+ if ((__predict_false(V_un_ctl == NULL)) && (!vnet_init_unhops()))
	+ return (ENOMEM);
	+ struct unhop_ctl *ctl = V_un_ctl;
	+
	+ struct nl_parsed_nhop attrs = {};
	+ error = nl_parse_nlmsg(hdr, &nhmsg_parser, npt, &attrs);
	+ if (error != 0)
	+ return (error);
	+
	+ /*
	+ * Get valid nha_id. Treat nha_id == 0 (auto-assignment) as a second-class
	+ * citizen.
	+ */
	+ if (attrs.nha_id == 0) {
	+ attrs.nha_id = find_spare_uidx(ctl);
	+ if (attrs.nha_id == 0) {
	+ NL_LOG(LOG_DEBUG, "Unable to get spare uidx");
	+ return (ENOSPC);
	+ }
	+ }
	+
	+ NL_LOG(LOG_DEBUG, "IFINDEX %d", attrs.nha_oif ? attrs.nha_oif->if_index : 0);
	+
	+ unhop = malloc(sizeof(struct user_nhop), M_NETLINK, M_NOWAIT \| M_ZERO);
	+ if (unhop == NULL) {
	+ NL_LOG(LOG_DEBUG, "Unable to allocate user_nhop");
	+ return (ENOMEM);
	+ }
	+ unhop->un_idx = attrs.nha_id;
	+ unhop->un_protocol = attrs.nh_protocol;
	+
	+ if (attrs.nha_group)
	+ error = newnhg(ctl, &attrs, unhop);
	+ else
	+ error = newnhop(&attrs, unhop);
	+
	+ if (error != 0) {
	+ free(unhop, M_NETLINK);
	+ return (error);
	+ }
	+
	+ UN_WLOCK(ctl);
	+ /* Check if uidx already exists */
	+ struct user_nhop *tmp = NULL;
	+ CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, unhop, tmp);
	+ if (tmp != NULL) {
	+ UN_WUNLOCK(ctl);
	+ NL_LOG(LOG_DEBUG, "nhop idx %u already exists", attrs.nha_id);
	+ destroy_unhop(unhop);
	+ return (EEXIST);
	+ }
	+ CHT_SLIST_INSERT_HEAD(&ctl->un_head, unhop, unhop);
	+ uint32_t num_buckets_new = CHT_SLIST_GET_RESIZE_BUCKETS(&ctl->un_head);
	+ UN_WUNLOCK(ctl);
	+
	+ /* Report addition of the next nexhop */
	+ struct netlink_walkargs wa = {
	+ .hdr.nlmsg_pid = hdr->nlmsg_pid,
	+ .hdr.nlmsg_seq = hdr->nlmsg_seq,
	+ .hdr.nlmsg_flags = hdr->nlmsg_flags,
	+ .hdr.nlmsg_type = NL_RTM_NEWNEXTHOP,
	+ };
	+
	+ struct nl_writer nw = {};
	+ if (!nlmsg_get_group_writer(&nw, NLMSG_SMALL, NETLINK_ROUTE, RTNLGRP_NEXTHOP)) {
	+ NL_LOG(LOG_DEBUG, "error allocating message writer");
	+ return (ENOMEM);
	+ }
	+
	+ dump_unhop(unhop, &wa.hdr, &nw);
	+ nlmsg_flush(&nw);
	+
	+ consider_resize(ctl, num_buckets_new);
	+
	+ return (0);
	+}
	+
	+static int
	+rtnl_handle_delnhop(struct nlmsghdr hdr, struct nlpcb nlp,
	+ struct nl_pstate *npt)
	+{
	+ struct unhop_ctl *ctl = atomic_load_ptr(&V_un_ctl);
	+ int error;
	+
	+ if (__predict_false(ctl == NULL))
	+ return (ESRCH);
	+
	+ struct nl_parsed_nhop attrs = {};
	+ error = nl_parse_nlmsg(hdr, &nhmsg_parser, npt, &attrs);
	+ if (error != 0)
	+ return (error);
	+
	+ if (attrs.nha_id == 0) {
	+ NL_LOG(LOG_DEBUG, "NHA_ID not set");
	+ return (EINVAL);
	+ }
	+
	+ error = delete_unhop(ctl, hdr, attrs.nha_id);
	+
	+ return (error);
	+}
	+
	+static bool
	+match_unhop(const struct nl_parsed_nhop attrs, struct user_nhop unhop)
	+{
	+ if (attrs->nha_id != 0 && unhop->un_idx != attrs->nha_id)
	+ return (false);
	+ if (attrs->nha_groups != 0 && unhop->un_nhgrp_src == NULL)
	+ return (false);
	+ if (attrs->nha_oif != NULL &&
	+ (unhop->un_nhop_src == NULL \|\| unhop->un_nhop_src->nh_ifp != attrs->nha_oif))
	+ return (false);
	+
	+ return (true);
	+}
	+
	+static int
	+rtnl_handle_getnhop(struct nlmsghdr hdr, struct nlpcb nlp,
	+ struct nl_pstate *npt)
	+{
	+ struct unhop_ctl *ctl = atomic_load_ptr(&V_un_ctl);
	+ struct user_nhop *unhop;
	+ UN_TRACKER;
	+ int error;
	+
	+ if (__predict_false(ctl == NULL))
	+ return (ESRCH);
	+
	+ struct nl_parsed_nhop attrs = {};
	+ error = nl_parse_nlmsg(hdr, &nhmsg_parser, npt, &attrs);
	+ if (error != 0)
	+ return (error);
	+
	+ struct netlink_walkargs wa = {
	+ .nw = npt->nw,
	+ .hdr.nlmsg_pid = hdr->nlmsg_pid,
	+ .hdr.nlmsg_seq = hdr->nlmsg_seq,
	+ .hdr.nlmsg_flags = hdr->nlmsg_flags,
	+ .hdr.nlmsg_type = NL_RTM_NEWNEXTHOP,
	+ };
	+
	+ if (attrs.nha_id != 0) {
	+ NL_LOG(LOG_DEBUG2, "searching for uidx %u", attrs.nha_id);
	+ struct user_nhop key= { .un_idx = attrs.nha_id };
	+ UN_RLOCK(ctl);
	+ CHT_SLIST_FIND_BYOBJ(&ctl->un_head, unhop, &key, unhop);
	+ UN_RUNLOCK(ctl);
	+
	+ if (unhop == NULL)
	+ return (ESRCH);
	+ dump_unhop(unhop, &wa.hdr, wa.nw);
	+ return (0);
	+ }
	+
	+ UN_RLOCK(ctl);
	+ wa.hdr.nlmsg_flags \|= NLM_F_MULTI;
	+ CHT_SLIST_FOREACH(&ctl->un_head, unhop, unhop) {
	+ if (UNHOP_IS_MASTER(unhop) && match_unhop(&attrs, unhop))
	+ dump_unhop(unhop, &wa.hdr, wa.nw);
	+ } CHT_SLIST_FOREACH_END;
	+ UN_RUNLOCK(ctl);
	+
	+ if (wa.error == 0) {
	+ if (!nlmsg_end_dump(wa.nw, wa.error, &wa.hdr))
	+ return (ENOMEM);
	+ }
	+ return (0);
	+}
	+
	+static const struct rtnl_cmd_handler cmd_handlers[] = {
	+ {
	+ .cmd = NL_RTM_NEWNEXTHOP,
	+ .name = "RTM_NEWNEXTHOP",
	+ .cb = &rtnl_handle_newnhop,
	+ .priv = PRIV_NET_ROUTE,
	+ },
	+ {
	+ .cmd = NL_RTM_DELNEXTHOP,
	+ .name = "RTM_DELNEXTHOP",
	+ .cb = &rtnl_handle_delnhop,
	+ .priv = PRIV_NET_ROUTE,
	+ },
	+ {
	+ .cmd = NL_RTM_GETNEXTHOP,
	+ .name = "RTM_GETNEXTHOP",
	+ .cb = &rtnl_handle_getnhop,
	+ }
	+};
	+
	+static const struct nlhdr_parser *all_parsers[] = { &nhmsg_parser };
	+
	+void
	+rtnl_nexthops_init()
	+{
	+ NL_VERIFY_PARSERS(all_parsers);
	+ rtnl_register_messages(cmd_handlers, NL_ARRAY_LEN(cmd_handlers));
	+}
	diff --git a/sys/netlink/route/route.h b/sys/netlink/route/route.h
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/route/route.h
	@@ -0,0 +1,366 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+/*
	+ * Route-related (RTM_<NEW\|DEL\|GET>ROUTE) message header and attributes.
	+ */
	+
	+#ifndef _NETLINK_ROUTE_ROUTE_H_
	+#define _NETLINK_ROUTE_ROUTE_H_
	+
	+/* Base header for all of the relevant messages */
	+struct rtmsg {
	+ unsigned char rtm_family; /* address family */
	+ unsigned char rtm_dst_len; /* Prefix length */
	+ unsigned char rtm_src_len; /* Source prefix length (not used) */
	+ unsigned char rtm_tos; /* Type of service (not used) */
	+ unsigned char rtm_table; /* rtable id */
	+ unsigned char rtm_protocol; /* Routing protocol id (RTPROT_) */
	+ unsigned char rtm_scope; /* Route distance (RT_SCOPE_) */
	+ unsigned char rtm_type; /* Route type (RTN_) */
	+ unsigned rtm_flags; /* Route flags (RTM_F_) */
	+};
	+
	+/*
	+ * RFC 3549, 3.1.1, route type (rtm_type field).
	+ */
	+enum {
	+ RTN_UNSPEC,
	+ RTN_UNICAST, /* Unicast route */
	+ RTN_LOCAL, /* Accept locally (not supported) */
	+ RTN_BROADCAST, /* Accept locally as broadcast, send as broadcast */
	+ RTN_ANYCAST, /* Accept locally as broadcast, but send as unicast */
	+ RTN_MULTICAST, /* Multicast route */
	+ RTN_BLACKHOLE, /* Drop traffic towards destination */
	+ RTN_UNREACHABLE, /* Destination is unreachable */
	+ RTN_PROHIBIT, /* Administratively prohibited */
	+ RTN_THROW, /* Not in this table (not supported) */
	+ RTN_NAT, /* Translate this address (not supported) */
	+ RTN_XRESOLVE, /* Use external resolver (not supported) */
	+ __RTN_MAX,
	+};
	+#define RTN_MAX (__RTN_MAX - 1)
	+
	+/*
	+ * RFC 3549, 3.1.1, protocol (Identifies what/who added the route).
	+ * Values larger than RTPROT_STATIC(4) are not interpreted by the
	+ * kernel, they are just for user information.
	+ */
	+#define RTPROT_UNSPEC 0
	+#define RTPROT_REDIRECT 1 /* Route installed by ICMP redirect */
	+#define RTPROT_KERNEL 2 /* Route installed by kernel */
	+#define RTPROT_BOOT 3 /* Route installed during boot */
	+#define RTPROT_STATIC 4 /* Route installed by administrator */
	+
	+#define RTPROT_GATED 8
	+#define RTPROT_RA 9
	+#define RTPROT_MRT 1
	+#define RTPROT_ZEBRA 11
	+#define RTPROT_BIRD 12
	+#define RTPROT_DNROUTED 13
	+#define RTPROT_XORP 14
	+#define RTPROT_NTK 15
	+#define RTPROT_DHCP 16
	+#define RTPROT_MROUTED 17
	+#define RTPROT_KEEPALIVED 18
	+#define RTPROT_BABEL 42
	+#define RTPROT_OPENR 99
	+#define RTPROT_BGP 186
	+#define RTPROT_ISIS 187
	+#define RTPROT_OSPF 188
	+#define RTPROT_RIP 189
	+#define RTPROT_EIGRP 192
	+
	+/*
	+ * RFC 3549 3.1.1 Route scope (valid distance to destination).
	+ *
	+ * The values between RT_SCOPE_UNIVERSE(0) and RT_SCOPE_SITE(200)
	+ * are available to the user.
	+ */
	+enum rt_scope_t {
	+ RT_SCOPE_UNIVERSE = 0,
	+ /* User defined values */
	+ RT_SCOPE_SITE = 200,
	+ RT_SCOPE_LINK = 253,
	+ RT_SCOPE_HOST = 254,
	+ RT_SCOPE_NOWHERE = 255
	+};
	+
	+/*
	+ * RFC 3549 3.1.1 Route flags (rtm_flags).
	+ * Is a composition of RTNH_F flags (0x1..0x40 range), RTM_F flags (below)
	+ * and per-protocol (IPv4/IPv6) flags.
	+ */
	+#define RTM_F_NOTIFY 0x00000100 /* not supported */
	+#define RTM_F_CLONED 0x00000200 /* not supported */
	+#define RTM_F_EQUALIZE 0x00000400 /* not supported */
	+#define RTM_F_PREFIX 0x00000800 /* not supported */
	+#define RTM_F_LOOKUP_TABLE 0x00001000 /* not supported */
	+#define RTM_F_FIB_MATCH 0x00002000 /* not supported */
	+#define RTM_F_OFFLOAD 0x00004000 /* not supported */
	+#define RTM_F_TRAP 0x00008000 /* not supported */
	+#define RTM_F_OFFLOAD_FAILED 0x20000000 /* not supported */
	+
	+/* Compatibility handling helpers */
	+#ifndef _KERNEL
	+#define NL_RTM_HDRLEN ((int)sizeof(struct rtmsg))
	+#define RTM_RTA(_rtm) ((struct rtattr )((char )(_rtm) + NL_RTM_HDRLEN))
	+#define RTM_PAYLOAD(_hdr) NLMSG_PAYLOAD((_hdr), NL_RTM_HDRLEN)
	+#endif
	+
	+/*
	+ * Routing table identifiers.
	+ * FreeBSD route table numbering starts from 0, where 0 is a valid default routing table.
	+ * Indicating "all tables" via netlink can be done by not including RTA_TABLE attribute
	+ * and keeping rtm_table=0 (compatibility) or setting RTA_TABLE value to RT_TABLE_UNSPEC.
	+ */
	+#define RT_TABLE_MAIN 0 /* RT_DEFAULT_FIB */
	+#define RT_TABLE_UNSPEC 0xFFFFFFFF /* RT_ALL_FIBS */
	+
	+enum rtattr_type_t {
	+ NL_RTA_UNSPEC,
	+ NL_RTA_DST = 1, /* binary, IPv4/IPv6 destination */
	+ NL_RTA_SRC = 2, /* binary, preferred source address */
	+ NL_RTA_IIF = 3, /* not supported */
	+ NL_RTA_OIF = 4, /* u32, transmit ifindex */
	+ NL_RTA_GATEWAY = 5, /* binary: IPv4/IPv6 gateway */
	+ NL_RTA_PRIORITY = 6, /* not supported */
	+ NL_RTA_PREFSRC = 7, /* not supported */
	+ NL_RTA_METRICS = 8, /* nested, list of NL_RTAX* attrs */
	+ NL_RTA_MULTIPATH = 9, /* binary, array of struct rtnexthop */
	+ NL_RTA_PROTOINFO = 10, /* not supported / deprecated */
	+ NL_RTA_KNH_ID = 10, /* u32, FreeBSD specific, kernel nexthop index */
	+ NL_RTA_FLOW = 11, /* not supported */
	+ NL_RTA_CACHEINFO = 12, /* not supported */
	+ NL_RTA_SESSION = 13, /* not supported / deprecated */
	+ NL_RTA_MP_ALGO = 14, /* not supported / deprecated */
	+ NL_RTA_RTFLAGS = 14, /* u32, FreeBSD specific, */
	+ NL_RTA_TABLE = 15, /* u32, fibnum */
	+ NL_RTA_MARK = 16, /* not supported */
	+ NL_RTA_MFC_STATS = 17, /* not supported */
	+ NL_RTA_VIA = 18, /* binary, struct rtvia */
	+ NL_RTA_NEWDST = 19, /* not supported */
	+ NL_RTA_PREF = 20, /* not supported */
	+ NL_RTA_ENCAP_TYPE = 21, /* not supported */
	+ NL_RTA_ENCAP = 22, /* not supported */
	+ NL_RTA_EXPIRES = 23, /* u32, seconds till expiration */
	+ NL_RTA_PAD = 24, /* not supported */
	+ NL_RTA_UID = 25, /* not supported */
	+ NL_RTA_TTL_PROPAGATE = 26, /* not supported */
	+ NL_RTA_IP_PROTO = 27, /* not supported */
	+ NL_RTA_SPORT = 28, /* not supported */
	+ NL_RTA_DPORT = 29, /* not supported */
	+ NL_RTA_NH_ID = 30, /* u32, nexthop/nexthop group index */
	+ __RTA_MAX
	+};
	+#define NL_RTA_MAX (__RTA_MAX - 1)
	+
	+/*
	+ * Attributes that can be used as filters:
	+ *
	+ */
	+
	+#ifndef _KERNEL
	+/*
	+ * RTA_* space has clashes with rtsock namespace.
	+ * Use NL_RTA_ prefix in the kernel and map to
	+ * RTA_ for userland.
	+ */
	+#define RTA_UNSPEC NL_RTA_UNSPEC
	+#define RTA_DST NL_RTA_DST
	+#define RTA_SRC NL_RTA_SRC
	+#define RTA_IIF NL_RTA_IIF
	+#define RTA_OIF NL_RTA_OIF
	+#define RTA_GATEWAY NL_RTA_GATEWAY
	+#define RTA_PRIORITY NL_RTA_PRIORITY
	+#define RTA_PREFSRC NL_RTA_PREFSRC
	+#define RTA_METRICS NL_RTA_METRICS
	+#define RTA_MULTIPATH NL_RTA_MULTIPATH
	+#define RTA_PROTOINFO NL_RTA_PROTOINFO
	+#define RTA_KNH_ID NL_RTA_KNH_ID
	+#define RTA_FLOW NL_RTA_FLOW
	+#define RTA_CACHEINFO NL_RTA_CACHEINFO
	+#define RTA_SESSION NL_RTA_SESSION
	+#define RTA_MP_ALGO NL_RTA_MP_ALGO
	+#define RTA_TABLE NL_RTA_TABLE
	+#define RTA_MARK NL_RTA_MARK
	+#define RTA_MFC_STATS NL_RTA_MFC_STATS
	+#define RTA_VIA NL_RTA_VIA
	+#define RTA_NEWDST NL_RTA_NEWDST
	+#define RTA_PREF NL_RTA_PREF
	+#define RTA_ENCAP_TYPE NL_RTA_ENCAP_TYPE
	+#define RTA_ENCAP NL_RTA_ENCAP
	+#define RTA_EXPIRES NL_RTA_EXPIRES
	+#define RTA_PAD NL_RTA_PAD
	+#define RTA_UID NL_RTA_UID
	+#define RTA_TTL_PROPAGATE NL_RTA_TTL_PROPAGATE
	+#define RTA_IP_PROTO NL_RTA_IP_PROTO
	+#define RTA_SPORT NL_RTA_SPORT
	+#define RTA_DPORT NL_RTA_DPORT
	+#define RTA_NH_ID NL_RTA_NH_ID
	+#define RTA_MAX NL_RTA_MAX
	+#endif
	+
	+/* route attribute header */
	+struct rtattr {
	+ unsigned short rta_len;
	+ unsigned short rta_type;
	+};
	+
	+#define NL_RTA_ALIGN_SIZE NL_ITEM_ALIGN_SIZE
	+#define NL_RTA_ALIGN NL_ITEM_ALIGN
	+#define NL_RTA_HDRLEN ((int)sizeof(struct rtattr))
	+#define NL_RTA_DATA_LEN(_rta) ((int)((_rta)->rta_len - NL_RTA_HDRLEN))
	+#define NL_RTA_DATA(_rta) NL_ITEM_DATA(_rta, NL_RTA_HDRLEN)
	+#define NL_RTA_DATA_CONST(_rta) NL_ITEM_DATA_CONST(_rta, NL_RTA_HDRLEN)
	+
	+/* Compatibility attribute handling helpers */
	+#ifndef _KERNEL
	+#define RTA_ALIGNTO NL_RTA_ALIGN_SIZE
	+#define RTA_ALIGN(_len) NL_RTA_ALIGN(_len)
	+#define _RTA_LEN(_rta) ((int)(_rta)->rta_len)
	+#define _RTA_ALIGNED_LEN(_rta) RTA_ALIGN(_RTA_LEN(_rta))
	+#define RTA_OK(_rta, _len) NL_ITEM_OK(_rta, _len, NL_RTA_HDRLEN, _RTA_LEN)
	+#define RTA_NEXT(_rta, _len) NL_ITEM_ITER(_rta, _len, _RTA_ALIGNED_LEN)
	+#define RTA_LENGTH(_len) (NL_RTA_HDRLEN + (_len))
	+#define RTA_SPACE(_len) RTA_ALIGN(RTA_LENGTH(_len))
	+#define RTA_DATA(_rta) NL_RTA_DATA(_rta)
	+#define RTA_PAYLOAD(_rta) ((int)(_RTA_LEN(_rta) - NL_RTA_HDRLEN))
	+#endif
	+
	+/* RTA attribute headers */
	+
	+/* RTA_VIA */
	+struct rtvia {
	+ sa_family_t rtvia_family;
	+ uint8_t rtvia_addr[0];
	+};
	+
	+/*
	+ * RTA_METRICS is a nested attribute, consisting of a list of
	+ * TLVs with types defined below.
	+ */
	+ enum {
	+ NL_RTAX_UNSPEC,
	+ NL_RTAX_LOCK = 1, /* not supported */
	+ NL_RTAX_MTU = 2, /* desired path MTU */
	+ NL_RTAX_WINDOW = 3, /* not supported */
	+ NL_RTAX_RTT = 4, /* not supported */
	+ NL_RTAX_RTTVAR = 5, /* not supported */
	+ NL_RTAX_SSTHRESH = 6, /* not supported */
	+ NL_RTAX_CWND = 7, /* not supported */
	+ NL_RTAX_ADVMSS = 8, /* not supported */
	+ NL_RTAX_REORDERING = 9, /* not supported */
	+ NL_RTAX_HOPLIMIT = 10, /* not supported */
	+ NL_RTAX_INITCWND = 11, /* not supporrted */
	+ NL_RTAX_FEATURES = 12, /* not supported */
	+ NL_RTAX_RTO_MIN = 13, /* not supported */
	+ NL_RTAX_INITRWND = 14, /* not supported */
	+ NL_RTAX_QUICKACK = 15, /* not supported */
	+ NL_RTAX_CC_ALGO = 15, /* not supported */
	+ NL_RTAX_FASTOPEN_NO_COOKIE = 16, /* not supported */
	+ __NL_RTAX_MAX
	+};
	+#define NL_RTAX_MAX (__NL_RTAX_MAX - 1)
	+
	+#define RTAX_FEATURE_ECN (1 << 0)
	+#define RTAX_FEATURE_SACK (1 << 1)
	+#define RTAX_FEATURE_TIMESTAMP (1 << 2)
	+#define RTAX_FEATURE_ALLFRAG (1 << 3)
	+
	+#define RTAX_FEATURE_MASK \
	+ (RTAX_FEATURE_ECN \| RTAX_FEATURE_SACK \| RTAX_FEATURE_TIMESTAMP \| \
	+ RTAX_FEATURE_ALLFRAG)
	+
	+#ifndef _KERNEL
	+
	+/*
	+ * RTAX_* space clashes with rtsock namespace.
	+ * Use NL_RTAX_ prefix in the kernel and map to
	+ * RTAX_ for userland.
	+ */
	+#define RTAX_UNSPEC NL_RTAX_UNSPEC
	+#define RTAX_LOCK NL_RTAX_LOCK
	+#define RTAX_MTU NL_RTAX_MTU
	+#define RTAX_WINDOW NL_RTAX_WINDOW
	+#define RTAX_RTT NL_RTAX_RTT
	+#define RTAX_RTTVAR NL_RTAX_RTTVAR
	+#define RTAX_SSTHRESH NL_RTAX_SSTHRESH
	+#define RTAX_CWND NL_RTAX_CWND
	+#define RTAX_ADVMSS NL_RTAX_ADVMSS
	+#define RTAX_REORDERING NL_RTAX_REORDERING
	+#define RTAX_HOPLIMIT NL_RTAX_HOPLIMIT
	+#define RTAX_INITCWND NL_RTAX_INITCWND
	+#define RTAX_FEATURES NL_RTAX_FEATURES
	+#define RTAX_RTO_MIN NL_RTAX_RTO_MIN
	+#define RTAX_INITRWND NL_RTAX_INITRWND
	+#define RTAX_QUICKACK NL_RTAX_QUICKACK
	+#define RTAX_CC_ALGO NL_RTAX_CC_ALGO
	+#define RTAX_FASTOPEN_NO_COOKIE NL_RTAX_FASTOPEN_NO_COOKIE
	+#endif
	+
	+/*
	+ * RTA_MULTIPATH consists of an array of rtnexthop structures.
	+ * Each rtnexthop structure contains RTA_GATEWAY or RTA_VIA
	+ * attribute following the header.
	+ */
	+struct rtnexthop {
	+ unsigned short rtnh_len;
	+ unsigned char rtnh_flags;
	+ unsigned char rtnh_hops; /* nexthop weight */
	+ int rtnh_ifindex;
	+};
	+
	+/* rtnh_flags */
	+#define RTNH_F_DEAD 0x01 /* not supported */
	+#define RTNH_F_PERVASIVE 0x02 /* not supported */
	+#define RTNH_F_ONLINK 0x04 /* not supported */
	+#define RTNH_F_OFFLOAD 0x08 /* not supported */
	+#define RTNH_F_LINKDOWN 0x10 /* not supported */
	+#define RTNH_F_UNRESOLVED 0x20 /* not supported */
	+#define RTNH_F_TRAP 0x40 /* not supported */
	+
	+#define RTNH_COMPARE_MASK (RTNH_F_DEAD \| RTNH_F_LINKDOWN \| \
	+ RTNH_F_OFFLOAD \| RTNH_F_TRAP)
	+
	+/* Macros to handle hexthops */
	+#define RTNH_ALIGNTO NL_ITEM_ALIGN_SIZE
	+#define RTNH_ALIGN(_len) NL_ITEM_ALIGN(_len)
	+#define RTNH_HDRLEN ((int)sizeof(struct rtnexthop))
	+#define _RTNH_LEN(_nh) ((int)(_nh)->rtnh_len)
	+#define _RTNH_ALIGNED_LEN(_nh) RTNH_ALIGN(_RTNH_LEN(_nh))
	+#define RTNH_OK(_nh, _len) NL_ITEM_OK(_nh, _len, RTNH_HDRLEN, _RTNH_LEN)
	+#define RTNH_NEXT(_nh) ((struct rtnexthop )((char )(_nh) + _RTNH_ALIGNED_LEN(_nh)))
	+#define RTNH_LENGTH(_len) (RTNH_HDRLEN + (_len))
	+#define RTNH_SPACE(_len) RTNH_ALIGN(RTNH_LENGTH(_len))
	+#define RTNH_DATA(_nh) ((struct rtattr *)NL_ITEM_DATA(_nh, RTNH_HDRLEN))
	+
	+struct rtgenmsg {
	+ unsigned char rtgen_family;
	+};
	+
	+#endif
	diff --git a/sys/netlink/route/route.c b/sys/netlink/route/route.c
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/route/route.c
	@@ -0,0 +1,972 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2021 Ng Peng Nam Sean
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+#include <sys/cdefs.h>
	+__FBSDID("$FreeBSD$");
	+#include "opt_inet.h"
	+#include "opt_inet6.h"
	+#include "opt_route.h"
	+#include <sys/types.h>
	+#include <sys/malloc.h>
	+#include <sys/rmlock.h>
	+#include <sys/socket.h>
	+
	+#include <net/if.h>
	+#include <net/route.h>
	+#include <net/route/nhop.h>
	+#include <net/route/route_ctl.h>
	+#include <net/route/route_var.h>
	+#include <netlink/netlink.h>
	+#include <netlink/netlink_ctl.h>
	+#include <netlink/netlink_route.h>
	+#include <netlink/route/route_var.h>
	+
	+#define DEBUG_MOD_NAME nl_route
	+#define DEBUG_MAX_LEVEL LOG_DEBUG3
	+#include <netlink/netlink_debug.h>
	+_DECLARE_DEBUG(LOG_DEBUG);
	+
	+static unsigned char
	+get_rtm_type(const struct nhop_object *nh)
	+{
	+ int nh_flags = nh->nh_flags;
	+
	+ /* Use the fact that nhg runtime flags are only NHF_MULTIPATH */
	+ if (nh_flags & NHF_BLACKHOLE)
	+ return (RTN_BLACKHOLE);
	+ else if (nh_flags & NHF_REJECT)
	+ return (RTN_PROHIBIT);
	+ return (RTN_UNICAST);
	+}
	+
	+static uint8_t
	+nl_get_rtm_protocol(const struct nhop_object *nh)
	+{
	+ if (NH_IS_NHGRP(nh)) {
	+ const struct nhgrp_object nhg = (const struct nhgrp_object )nh;
	+ uint8_t origin = nhgrp_get_origin(nhg);
	+ if (origin != RTPROT_UNSPEC)
	+ return (origin);
	+ nh = nhg->nhops[0];
	+ }
	+ uint8_t origin = nhop_get_origin(nh);
	+ if (origin != RTPROT_UNSPEC)
	+ return (origin);
	+ /* TODO: remove guesswork once all kernel users fill in origin */
	+ int rt_flags = nhop_get_rtflags(nh);
	+ if (rt_flags & RTF_PROTO1)
	+ return (RTPROT_ZEBRA);
	+ if (rt_flags & RTF_STATIC)
	+ return (RTPROT_STATIC);
	+ return (RTPROT_KERNEL);
	+}
	+
	+static int
	+get_rtmsg_type_from_rtsock(int cmd)
	+{
	+ switch (cmd) {
	+ case RTM_ADD:
	+ case RTM_CHANGE:
	+ case RTM_GET:
	+ return NL_RTM_NEWROUTE;
	+ case RTM_DELETE:
	+ return NL_RTM_DELROUTE;
	+ }
	+
	+ return (0);
	+}
	+
	+/*
	+ * fibnum heuristics
	+ *
	+ * if (dump && rtm_table == 0 && !rta_table) RT_ALL_FIBS
	+ * msg rtm_table RTA_TABLE result
	+ * RTM_GETROUTE/dump 0 - RT_ALL_FIBS
	+ * RTM_GETROUTE/dump 1 - 1
	+ * RTM_GETROUTE/get 0 - 0
	+ *
	+ */
	+
	+static struct nhop_object *
	+rc_get_nhop(const struct rib_cmd_info *rc)
	+{
	+ return ((rc->rc_cmd == RTM_DELETE) ? rc->rc_nh_old : rc->rc_nh_new);
	+}
	+
	+static void
	+dump_rc_nhop_gw(struct nl_writer nw, const struct nhop_object nh)
	+{
	+ int upper_family;
	+
	+ switch (nhop_get_neigh_family(nh)) {
	+ case AF_LINK:
	+ /* onlink prefix, skip */
	+ break;
	+ case AF_INET:
	+ nlattr_add(nw, NL_RTA_GATEWAY, 4, &nh->gw4_sa.sin_addr);
	+ break;
	+ case AF_INET6:
	+ upper_family = nhop_get_upper_family(nh);
	+ if (upper_family == AF_INET6) {
	+ nlattr_add(nw, NL_RTA_GATEWAY, 16, &nh->gw6_sa.sin6_addr);
	+ } else if (upper_family == AF_INET) {
	+ /* IPv4 over IPv6 */
	+ char buf[20];
	+ struct rtvia via = (struct rtvia )&buf[0];
	+ via->rtvia_family = AF_INET6;
	+ memcpy(via->rtvia_addr, &nh->gw6_sa.sin6_addr, 16);
	+ nlattr_add(nw, NL_RTA_VIA, 17, via);
	+ }
	+ break;
	+ }
	+}
	+
	+static void
	+dump_rc_nhop_mtu(struct nl_writer nw, const struct nhop_object nh)
	+{
	+ int nla_len = sizeof(struct nlattr) * 2 + sizeof(uint32_t);
	+ struct nlattr *nla = nlmsg_reserve_data(nw, nla_len, struct nlattr);
	+
	+ if (nla == NULL)
	+ return;
	+ nla->nla_type = NL_RTA_METRICS;
	+ nla->nla_len = nla_len;
	+ nla++;
	+ nla->nla_type = NL_RTAX_MTU;
	+ nla->nla_len = sizeof(struct nlattr) + sizeof(uint32_t);
	+ ((uint32_t )(nla + 1)) = nh->nh_mtu;
	+}
	+
	+static void
	+dump_rc_nhg(struct nl_writer nw, const struct nhgrp_object nhg, struct rtmsg *rtm)
	+{
	+ uint32_t uidx = nhgrp_get_uidx(nhg);
	+ uint32_t num_nhops;
	+ const struct weightened_nhop *wn = nhgrp_get_nhops(nhg, &num_nhops);
	+ uint32_t base_rtflags = nhop_get_rtflags(wn[0].nh);
	+
	+ if (uidx != 0)
	+ nlattr_add_u32(nw, NL_RTA_NH_ID, uidx);
	+
	+ nlattr_add_u32(nw, NL_RTA_RTFLAGS, base_rtflags);
	+ int off = nlattr_add_nested(nw, NL_RTA_MULTIPATH);
	+ if (off == 0)
	+ return;
	+
	+ for (int i = 0; i < num_nhops; i++) {
	+ int nh_off = nlattr_save_offset(nw);
	+ struct rtnexthop *rtnh = nlmsg_reserve_object(nw, struct rtnexthop);
	+ if (rtnh == NULL)
	+ return;
	+ rtnh->rtnh_flags = 0;
	+ rtnh->rtnh_ifindex = wn[i].nh->nh_ifp->if_index;
	+ rtnh->rtnh_hops = wn[i].weight;
	+ dump_rc_nhop_gw(nw, wn[i].nh);
	+ uint32_t rtflags = nhop_get_rtflags(wn[i].nh);
	+ if (rtflags != base_rtflags)
	+ nlattr_add_u32(nw, NL_RTA_RTFLAGS, rtflags);
	+ if (rtflags & RTF_FIXEDMTU)
	+ dump_rc_nhop_mtu(nw, wn[i].nh);
	+ rtnh = nlattr_restore_offset(nw, nh_off, struct rtnexthop);
	+ /*
	+ * nlattr_add() allocates 4-byte aligned storage, no need to aligh
	+ * length here
	+ * */
	+ rtnh->rtnh_len = nlattr_save_offset(nw) - nh_off;
	+ }
	+ nlattr_set_len(nw, off);
	+}
	+
	+static void
	+dump_rc_nhop(struct nl_writer nw, const struct nhop_object nh, struct rtmsg *rtm)
	+{
	+ if (NH_IS_NHGRP(nh)) {
	+ dump_rc_nhg(nw, (const struct nhgrp_object *)nh, rtm);
	+ return;
	+ }
	+
	+ uint32_t rtflags = nhop_get_rtflags(nh);
	+
	+ /*
	+ * IPv4 over IPv6
	+ * ('RTA_VIA', {'family': 10, 'addr': 'fe80::20c:29ff:fe67:2dd'}), ('RTA_OIF', 2),
	+ * IPv4 w/ gw
	+ * ('RTA_GATEWAY', '172.16.107.131'), ('RTA_OIF', 2)],
	+ * Direct route:
	+ * ('RTA_OIF', 2)
	+ */
	+ if (nh->nh_flags & NHF_GATEWAY)
	+ dump_rc_nhop_gw(nw, nh);
	+
	+ uint32_t uidx = nhop_get_uidx(nh);
	+ if (uidx != 0)
	+ nlattr_add_u32(nw, NL_RTA_NH_ID, uidx);
	+ nlattr_add_u32(nw, NL_RTA_KNH_ID, nhop_get_idx(nh));
	+ nlattr_add_u32(nw, NL_RTA_RTFLAGS, rtflags);
	+
	+ if (rtflags & RTF_FIXEDMTU)
	+ dump_rc_nhop_mtu(nw, nh);
	+ uint32_t nh_expire = nhop_get_expire(nh);
	+ if (nh_expire > 0)
	+ nlattr_add_u32(nw, NL_RTA_EXPIRES, nh_expire - time_uptime);
	+
	+ /* In any case, fill outgoing interface */
	+ nlattr_add_u32(nw, NL_RTA_OIF, nh->nh_ifp->if_index);
	+}
	+
	+/*
	+ * Dumps output from a rib command into an rtmsg
	+ */
	+
	+static int
	+dump_px(uint32_t fibnum, const struct nlmsghdr *hdr,
	+ const struct rtentry rt, struct route_nhop_data rnd,
	+ struct nl_writer *nw)
	+{
	+ struct rtmsg *rtm;
	+ int error = 0;
	+
	+ NET_EPOCH_ASSERT();
	+
	+ if (!nlmsg_reply(nw, hdr, sizeof(struct rtmsg)))
	+ goto enomem;
	+
	+ int family = rt_get_family(rt);
	+ int rtm_off = nlattr_save_offset(nw);
	+ rtm = nlmsg_reserve_object(nw, struct rtmsg);
	+ rtm->rtm_family = family;
	+ rtm->rtm_dst_len = 0;
	+ rtm->rtm_src_len = 0;
	+ rtm->rtm_tos = 0;
	+ if (fibnum < 255)
	+ rtm->rtm_table = (unsigned char)fibnum;
	+ rtm->rtm_scope = RT_SCOPE_UNIVERSE;
	+ if (!NH_IS_NHGRP(rnd->rnd_nhop)) {
	+ rtm->rtm_protocol = nl_get_rtm_protocol(rnd->rnd_nhop);
	+ rtm->rtm_type = get_rtm_type(rnd->rnd_nhop);
	+ } else {
	+ rtm->rtm_protocol = RTPROT_UNSPEC; /* TODO: protocol from nhg? */
	+ rtm->rtm_type = RTN_UNICAST;
	+ }
	+
	+ nlattr_add_u32(nw, NL_RTA_TABLE, fibnum);
	+
	+ int plen = 0;
	+ uint32_t scopeid = 0;
	+ switch (family) {
	+ case AF_INET:
	+ {
	+ struct in_addr addr;
	+ rt_get_inet_prefix_plen(rt, &addr, &plen, &scopeid);
	+ nlattr_add(nw, NL_RTA_DST, 4, &addr);
	+ break;
	+ }
	+ case AF_INET6:
	+ {
	+ struct in6_addr addr;
	+ rt_get_inet6_prefix_plen(rt, &addr, &plen, &scopeid);
	+ nlattr_add(nw, NL_RTA_DST, 16, &addr);
	+ break;
	+ }
	+ default:
	+ FIB_LOG(LOG_NOTICE, fibnum, family, "unsupported rt family: %d", family);
	+ error = EAFNOSUPPORT;
	+ goto flush;
	+ }
	+
	+ rtm = nlattr_restore_offset(nw, rtm_off, struct rtmsg);
	+ if (plen > 0)
	+ rtm->rtm_dst_len = plen;
	+ dump_rc_nhop(nw, rnd->rnd_nhop, rtm);
	+
	+ if (nlmsg_end(nw))
	+ return (0);
	+enomem:
	+ error = ENOMEM;
	+flush:
	+ nlmsg_abort(nw);
	+ return (error);
	+}
	+
	+static int
	+family_to_group(int family)
	+{
	+ switch (family) {
	+ case AF_INET:
	+ return (RTNLGRP_IPV4_ROUTE);
	+ case AF_INET6:
	+ return (RTNLGRP_IPV6_ROUTE);
	+ }
	+ return (0);
	+}
	+
	+
	+static void
	+report_operation(uint32_t fibnum, struct rib_cmd_info *rc,
	+ struct nlpcb nlp, struct nlmsghdr hdr)
	+{
	+ struct nl_writer nw;
	+
	+ uint32_t group_id = family_to_group(rt_get_family(rc->rc_rt));
	+ if (nlmsg_get_group_writer(&nw, NLMSG_SMALL, NETLINK_ROUTE, group_id)) {
	+ struct route_nhop_data rnd = {
	+ .rnd_nhop = rc_get_nhop(rc),
	+ .rnd_weight = rc->rc_nh_weight,
	+ };
	+ hdr->nlmsg_flags &= ~(NLM_F_REPLACE \| NLM_F_CREATE);
	+ hdr->nlmsg_flags &= ~(NLM_F_EXCL \| NLM_F_APPEND);
	+ switch (rc->rc_cmd) {
	+ case RTM_ADD:
	+ hdr->nlmsg_type = NL_RTM_NEWROUTE;
	+ hdr->nlmsg_flags \|= NLM_F_CREATE \| NLM_F_EXCL;
	+ break;
	+ case RTM_CHANGE:
	+ hdr->nlmsg_type = NL_RTM_NEWROUTE;
	+ hdr->nlmsg_flags \|= NLM_F_REPLACE;
	+ break;
	+ case RTM_DELETE:
	+ hdr->nlmsg_type = NL_RTM_DELROUTE;
	+ break;
	+ }
	+ dump_px(fibnum, hdr, rc->rc_rt, &rnd, &nw);
	+ nlmsg_flush(&nw);
	+ }
	+
	+ rtsock_callback_p->route_f(fibnum, rc);
	+}
	+
	+struct rta_mpath_nh {
	+ struct sockaddr *gw;
	+ struct ifnet *ifp;
	+ uint8_t rtnh_flags;
	+ uint8_t rtnh_weight;
	+};
	+
	+#define _IN(_field) offsetof(struct rtnexthop, _field)
	+#define _OUT(_field) offsetof(struct rta_mpath_nh, _field)
	+const static struct nlattr_parser nla_p_rtnh[] = {
	+ { .type = NL_RTA_GATEWAY, .off = _OUT(gw), .cb = nlattr_get_ip },
	+ { .type = NL_RTA_VIA, .off = _OUT(gw), .cb = nlattr_get_ipvia },
	+};
	+const static struct nlfield_parser nlf_p_rtnh[] = {
	+ { .off_in = _IN(rtnh_flags), .off_out = _OUT(rtnh_flags), .cb = nlf_get_u8 },
	+ { .off_in = _IN(rtnh_hops), .off_out = _OUT(rtnh_weight), .cb = nlf_get_u8 },
	+ { .off_in = _IN(rtnh_ifindex), .off_out = _OUT(ifp), .cb = nlf_get_ifpz },
	+};
	+#undef _IN
	+#undef _OUT
	+NL_DECLARE_PARSER(mpath_parser, struct rtnexthop, nlf_p_rtnh, nla_p_rtnh);
	+
	+struct rta_mpath {
	+ int num_nhops;
	+ struct rta_mpath_nh nhops[0];
	+};
	+
	+static int
	+nlattr_get_multipath(struct nlattr nla, struct nl_pstate npt, const void arg, void target)
	+{
	+ int data_len = nla->nla_len - sizeof(struct nlattr);
	+ struct rtnexthop *rtnh;
	+
	+ int max_nhops = data_len / sizeof(struct rtnexthop);
	+
	+ struct rta_mpath mp = npt_alloc(npt, (max_nhops + 2) sizeof(struct rta_mpath_nh));
	+ mp->num_nhops = 0;
	+
	+ for (rtnh = (struct rtnexthop *)(nla + 1); data_len > 0; ) {
	+ struct rta_mpath_nh *mpnh = &mp->nhops[mp->num_nhops++];
	+
	+ int error = nl_parse_header(rtnh, rtnh->rtnh_len, &mpath_parser,
	+ npt, mpnh);
	+ if (error != 0) {
	+ NLMSG_REPORT_ERR_MSG(npt, "RTA_MULTIPATH: nexhop %d: parse failed",
	+ mp->num_nhops - 1);
	+ return (error);
	+ }
	+
	+ int len = NL_ITEM_ALIGN(rtnh->rtnh_len);
	+ data_len -= len;
	+ rtnh = (struct rtnexthop )((char )rtnh + len);
	+ }
	+ if (data_len != 0 \|\| mp->num_nhops == 0) {
	+ NLMSG_REPORT_ERR_MSG(npt, "invalid RTA_MULTIPATH attr");
	+ return (EINVAL);
	+ }
	+
	+ ((struct rta_mpath *)target) = mp;
	+ return (0);
	+}
	+
	+
	+struct nl_parsed_route {
	+ struct sockaddr *rta_dst;
	+ struct sockaddr *rta_gw;
	+ struct ifnet *rta_oif;
	+ struct rta_mpath *rta_multipath;
	+ uint32_t rta_table;
	+ uint32_t rta_rtflags;
	+ uint32_t rta_nh_id;
	+ uint32_t rtax_mtu;
	+ uint8_t rtm_family;
	+ uint8_t rtm_dst_len;
	+};
	+
	+#define _IN(_field) offsetof(struct rtmsg, _field)
	+#define _OUT(_field) offsetof(struct nl_parsed_route, _field)
	+static struct nlattr_parser nla_p_rtmetrics[] = {
	+ { .type = NL_RTAX_MTU, .off = _OUT(rtax_mtu), .cb = nlattr_get_uint32 },
	+};
	+NL_DECLARE_ATTR_PARSER(metrics_parser, nla_p_rtmetrics);
	+
	+static const struct nlattr_parser nla_p_rtmsg[] = {
	+ { .type = NL_RTA_DST, .off = _OUT(rta_dst), .cb = nlattr_get_ip },
	+ { .type = NL_RTA_OIF, .off = _OUT(rta_oif), .cb = nlattr_get_ifp },
	+ { .type = NL_RTA_GATEWAY, .off = _OUT(rta_gw), .cb = nlattr_get_ip },
	+ { .type = NL_RTA_METRICS, .arg = &metrics_parser, .cb = nlattr_get_nested },
	+ { .type = NL_RTA_MULTIPATH, .off = _OUT(rta_multipath), .cb = nlattr_get_multipath },
	+ { .type = NL_RTA_RTFLAGS, .off = _OUT(rta_rtflags), .cb = nlattr_get_uint32 },
	+ { .type = NL_RTA_TABLE, .off = _OUT(rta_table), .cb = nlattr_get_uint32 },
	+ { .type = NL_RTA_VIA, .off = _OUT(rta_gw), .cb = nlattr_get_ipvia },
	+ { .type = NL_RTA_NH_ID, .off = _OUT(rta_nh_id), .cb = nlattr_get_uint32 },
	+};
	+
	+static const struct nlfield_parser nlf_p_rtmsg[] = {
	+ {.off_in = _IN(rtm_family), .off_out = _OUT(rtm_family), .cb = nlf_get_u8 },
	+ {.off_in = _IN(rtm_dst_len), .off_out = _OUT(rtm_dst_len), .cb = nlf_get_u8 },
	+};
	+#undef _IN
	+#undef _OUT
	+NL_DECLARE_PARSER(rtm_parser, struct rtmsg, nlf_p_rtmsg, nla_p_rtmsg);
	+
	+struct netlink_walkargs {
	+ struct nl_writer *nw;
	+ struct route_nhop_data rnd;
	+ struct nlmsghdr hdr;
	+ struct nlpcb *nlp;
	+ uint32_t fibnum;
	+ int family;
	+ int error;
	+ int count;
	+ int dumped;
	+ int dumped_tables;
	+};
	+
	+static int
	+dump_rtentry(struct rtentry rt, void _arg)
	+{
	+ struct netlink_walkargs wa = (struct netlink_walkargs )_arg;
	+ int error;
	+
	+ wa->count++;
	+ if (wa->error != 0)
	+ return (0);
	+ wa->dumped++;
	+
	+ rt_get_rnd(rt, &wa->rnd);
	+
	+ error = dump_px(wa->fibnum, &wa->hdr, rt, &wa->rnd, wa->nw);
	+
	+ IF_DEBUG_LEVEL(LOG_DEBUG3) {
	+ char rtbuf[INET6_ADDRSTRLEN + 5];
	+ FIB_LOG(LOG_DEBUG3, wa->fibnum, wa->family,
	+ "Dump %s, offset %u, error %d",
	+ rt_print_buf(rt, rtbuf, sizeof(rtbuf)),
	+ wa->nw->offset, error);
	+ }
	+ wa->error = error;
	+
	+ return (0);
	+}
	+
	+static void
	+dump_rtable_one(struct netlink_walkargs *wa, uint32_t fibnum, int family)
	+{
	+ FIB_LOG(LOG_DEBUG2, fibnum, family, "Start dump");
	+ wa->count = 0;
	+ wa->dumped = 0;
	+
	+ rib_walk(fibnum, family, false, dump_rtentry, wa);
	+
	+ wa->dumped_tables++;
	+
	+ FIB_LOG(LOG_DEBUG2, fibnum, family, "End dump, iterated %d dumped %d",
	+ wa->count, wa->dumped);
	+ NL_LOG(LOG_DEBUG2, "Current offset: %d", wa->nw->offset);
	+}
	+
	+static int
	+dump_rtable_fib(struct netlink_walkargs *wa, uint32_t fibnum, int family)
	+{
	+ wa->fibnum = fibnum;
	+
	+ if (family == AF_UNSPEC) {
	+ for (int i = 0; i < AF_MAX; i++) {
	+ if (rt_tables_get_rnh(fibnum, i) != 0) {
	+ wa->family = i;
	+ dump_rtable_one(wa, fibnum, i);
	+ if (wa->error != 0)
	+ break;
	+ }
	+ }
	+ } else {
	+ if (rt_tables_get_rnh(fibnum, family) != 0) {
	+ wa->family = family;
	+ dump_rtable_one(wa, fibnum, family);
	+ }
	+ }
	+
	+ return (wa->error);
	+}
	+
	+static int
	+handle_rtm_getroute(struct nlpcb nlp, struct nl_parsed_route attrs,
	+ struct nlmsghdr hdr, struct nl_pstate npt)
	+{
	+ RIB_RLOCK_TRACKER;
	+ struct rib_head *rnh;
	+ struct rtentry *rt;
	+ uint32_t fibnum = attrs->rta_table;
	+ sa_family_t family = attrs->rtm_family;
	+
	+ if (attrs->rta_dst == NULL) {
	+ NLMSG_REPORT_ERR_MSG(npt, "No RTA_DST supplied");
	+ return (EINVAL);
	+ }
	+
	+ FIB_LOG(LOG_DEBUG, fibnum, family, "getroute called");
	+
	+ rnh = rt_tables_get_rnh(fibnum, family);
	+ if (rnh == NULL)
	+ return (EAFNOSUPPORT);
	+
	+ RIB_RLOCK(rnh);
	+
	+ rt = (struct rtentry *)rnh->rnh_matchaddr(attrs->rta_dst, &rnh->head);
	+ if (rt == NULL) {
	+ RIB_RUNLOCK(rnh);
	+ return (ESRCH);
	+ }
	+
	+ struct route_nhop_data rnd;
	+ rt_get_rnd(rt, &rnd);
	+ rnd.rnd_nhop = nhop_select_func(rnd.rnd_nhop, 0);
	+
	+ RIB_RUNLOCK(rnh);
	+
	+ IF_DEBUG_LEVEL(LOG_DEBUG2) {
	+ char rtbuf[NHOP_PRINT_BUFSIZE] __unused, nhbuf[NHOP_PRINT_BUFSIZE] __unused;
	+ FIB_LOG(LOG_DEBUG2, fibnum, family, "getroute completed: got %s for %s",
	+ nhop_print_buf_any(rnd.rnd_nhop, nhbuf, sizeof(nhbuf)),
	+ rt_print_buf(rt, rtbuf, sizeof(rtbuf)));
	+ }
	+
	+ hdr->nlmsg_type = NL_RTM_NEWROUTE;
	+ dump_px(fibnum, hdr, rt, &rnd, npt->nw);
	+
	+ return (0);
	+}
	+
	+static int
	+handle_rtm_dump(struct nlpcb *nlp, uint32_t fibnum, int family,
	+ struct nlmsghdr hdr, struct nl_writer nw)
	+{
	+ struct netlink_walkargs wa = {
	+ .nlp = nlp,
	+ .nw = nw,
	+ .hdr.nlmsg_pid = hdr->nlmsg_pid,
	+ .hdr.nlmsg_seq = hdr->nlmsg_seq,
	+ .hdr.nlmsg_type = NL_RTM_NEWROUTE,
	+ .hdr.nlmsg_flags = hdr->nlmsg_flags \| NLM_F_MULTI,
	+ };
	+
	+ if (fibnum == RT_TABLE_UNSPEC) {
	+ for (int i = 0; i < V_rt_numfibs; i++) {
	+ dump_rtable_fib(&wa, fibnum, family);
	+ if (wa.error != 0)
	+ break;
	+ }
	+ } else
	+ dump_rtable_fib(&wa, fibnum, family);
	+
	+ if (wa.error == 0 && wa.dumped_tables == 0) {
	+ FIB_LOG(LOG_DEBUG, fibnum, family, "incorrect fibnum/family");
	+ wa.error = ESRCH;
	+ // How do we propagate it?
	+ }
	+
	+ if (!nlmsg_end_dump(wa.nw, wa.error, &wa.hdr)) {
	+ NL_LOG(LOG_DEBUG, "Unable to finalize the dump");
	+ return (ENOMEM);
	+ }
	+
	+ return (wa.error);
	+}
	+
	+static struct nhop_object *
	+finalize_nhop(struct nhop_object nh, int perror)
	+{
	+ /*
	+ * The following MUST be filled:
	+ * nh_ifp, nh_ifa, nh_gw
	+ */
	+ if (nh->gw_sa.sa_family == 0) {
	+ /*
	+ * Empty gateway. Can be direct route with RTA_OIF set.
	+ */
	+ if (nh->nh_ifp != NULL)
	+ nhop_set_direct_gw(nh, nh->nh_ifp);
	+ else {
	+ NL_LOG(LOG_DEBUG, "empty gateway and interface, skipping");
	+ *perror = EINVAL;
	+ return (NULL);
	+ }
	+ /* Both nh_ifp and gateway are set */
	+ } else {
	+ /* Gateway is set up, we can derive ifp if not set */
	+ if (nh->nh_ifp == NULL) {
	+ struct ifaddr *ifa = ifa_ifwithnet(&nh->gw_sa, 1, nhop_get_fibnum(nh));
	+ if (ifa == NULL) {
	+ NL_LOG(LOG_DEBUG, "Unable to determine ifp, skipping");
	+ *perror = EINVAL;
	+ return (NULL);
	+ }
	+ nhop_set_transmit_ifp(nh, ifa->ifa_ifp);
	+ }
	+ }
	+ /* Both nh_ifp and gateway are set */
	+ if (nh->nh_ifa == NULL) {
	+ struct ifaddr *ifa = ifaof_ifpforaddr(&nh->gw_sa, nh->nh_ifp);
	+ if (ifa == NULL) {
	+ NL_LOG(LOG_DEBUG, "Unable to determine ifa, skipping");
	+ *perror = EINVAL;
	+ return (NULL);
	+ }
	+ nhop_set_src(nh, ifa);
	+ }
	+
	+ return (nhop_get_nhop(nh, perror));
	+}
	+
	+static int
	+get_pxflag(const struct nl_parsed_route *attrs)
	+{
	+ int pxflag = 0;
	+ switch (attrs->rtm_family) {
	+ case AF_INET:
	+ if (attrs->rtm_dst_len == 32)
	+ pxflag = NHF_HOST;
	+ else if (attrs->rtm_dst_len == 0)
	+ pxflag = NHF_DEFAULT;
	+ break;
	+ case AF_INET6:
	+ if (attrs->rtm_dst_len == 32)
	+ pxflag = NHF_HOST;
	+ else if (attrs->rtm_dst_len == 0)
	+ pxflag = NHF_DEFAULT;
	+ break;
	+ }
	+
	+ return (pxflag);
	+}
	+
	+static int
	+get_op_flags(int nlm_flags)
	+{
	+ int op_flags = 0;
	+
	+ op_flags \|= (nlm_flags & NLM_F_REPLACE) ? RTM_F_REPLACE : 0;
	+ op_flags \|= (nlm_flags & NLM_F_EXCL) ? RTM_F_EXCL : 0;
	+ op_flags \|= (nlm_flags & NLM_F_CREATE) ? RTM_F_CREATE : 0;
	+ op_flags \|= (nlm_flags & NLM_F_APPEND) ? RTM_F_APPEND : 0;
	+
	+ return (op_flags);
	+}
	+
	+static int
	+create_nexthop_one(struct nl_parsed_route attrs, struct rta_mpath_nh mpnh,
	+ struct nl_pstate npt, struct nhop_object *pnh)
	+{
	+ int error;
	+
	+ if (mpnh->gw == NULL)
	+ return (EINVAL);
	+
	+ struct nhop_object *nh = nhop_alloc(attrs->rta_table, attrs->rtm_family);
	+ if (nh == NULL)
	+ return (ENOMEM);
	+
	+ nhop_set_gw(nh, mpnh->gw, true);
	+ if (mpnh->ifp != NULL)
	+ nhop_set_transmit_ifp(nh, mpnh->ifp);
	+ nhop_set_rtflags(nh, attrs->rta_rtflags);
	+
	+ *pnh = finalize_nhop(nh, &error);
	+
	+ return (error);
	+}
	+
	+static struct nhop_object *
	+create_nexthop_from_attrs(struct nl_parsed_route *attrs,
	+ struct nl_pstate npt, int perror)
	+{
	+ struct nhop_object *nh;
	+ int error = 0;
	+
	+ if (attrs->rta_multipath != NULL) {
	+ /* Multipath w/o explicit nexthops */
	+ int num_nhops = attrs->rta_multipath->num_nhops;
	+ struct weightened_nhop wn = npt_alloc(npt, sizeof(wn) * num_nhops);
	+ nh = NULL;
	+
	+ for (int i = 0; i < num_nhops; i++) {
	+ struct rta_mpath_nh *mpnh = &attrs->rta_multipath->nhops[i];
	+
	+ error = create_nexthop_one(attrs, mpnh, npt, &wn[i].nh);
	+ if (error != 0) {
	+ for (int j = 0; j < i; j++)
	+ nhop_free(wn[j].nh);
	+ break;
	+ }
	+ wn[i].weight = mpnh->rtnh_weight > 0 ? mpnh->rtnh_weight : 1;
	+ }
	+ if (error == 0) {
	+ struct rib_head *rh = nhop_get_rh(wn[0].nh);
	+
	+ error = nhgrp_get_group(rh, wn, num_nhops, 0,
	+ (struct nhgrp_object **)&nh);
	+
	+ for (int i = 0; i < num_nhops; i++)
	+ nhop_free(wn[i].nh);
	+ }
	+ *perror = error;
	+ } else {
	+ nh = nhop_alloc(attrs->rta_table, attrs->rtm_family);
	+ if (nh == NULL) {
	+ *perror = ENOMEM;
	+ return (NULL);
	+ }
	+ if (attrs->rta_gw != NULL)
	+ nhop_set_gw(nh, attrs->rta_gw, true);
	+ if (attrs->rta_oif != NULL)
	+ nhop_set_transmit_ifp(nh, attrs->rta_oif);
	+ if (attrs->rtax_mtu != 0)
	+ nhop_set_mtu(nh, attrs->rtax_mtu, true);
	+ if (attrs->rta_rtflags & RTF_BROADCAST)
	+ nhop_set_broadcast(nh, true);
	+ if (attrs->rta_rtflags & RTF_BLACKHOLE)
	+ nhop_set_blackhole(nh, NHF_BLACKHOLE);
	+ if (attrs->rta_rtflags & RTF_REJECT)
	+ nhop_set_blackhole(nh, NHF_REJECT);
	+ nhop_set_rtflags(nh, attrs->rta_rtflags);
	+ nh = finalize_nhop(nh, perror);
	+ }
	+
	+ return (nh);
	+}
	+
	+static int
	+rtnl_handle_newroute(struct nlmsghdr hdr, struct nlpcb nlp,
	+ struct nl_pstate *npt)
	+{
	+ struct rib_cmd_info rc = {};
	+ struct nhop_object *nh = NULL;
	+ int error;
	+
	+ struct nl_parsed_route attrs = {};
	+ error = nl_parse_nlmsg(hdr, &rtm_parser, npt, &attrs);
	+ if (error != 0)
	+ return (error);
	+
	+ /* Check if we have enough data */
	+ if (attrs.rta_dst == NULL) {
	+ NL_LOG(LOG_DEBUG, "missing RTA_DST");
	+ return (EINVAL);
	+ }
	+
	+ if (attrs.rta_nh_id != 0) {
	+ /* Referenced uindex */
	+ int pxflag = get_pxflag(&attrs);
	+ nh = nl_find_nhop(attrs.rta_table, attrs.rtm_family, attrs.rta_nh_id,
	+ pxflag, &error);
	+ if (error != 0)
	+ return (error);
	+ } else {
	+ nh = create_nexthop_from_attrs(&attrs, npt, &error);
	+ if (error != 0) {
	+ NL_LOG(LOG_DEBUG, "Error creating nexthop");
	+ return (error);
	+ }
	+ }
	+
	+ int weight = NH_IS_NHGRP(nh) ? 0 : RT_DEFAULT_WEIGHT;
	+ struct route_nhop_data rnd = { .rnd_nhop = nh, .rnd_weight = weight };
	+ int op_flags = get_op_flags(hdr->nlmsg_flags);
	+
	+ error = rib_add_route_px(attrs.rta_table, attrs.rta_dst, attrs.rtm_dst_len,
	+ &rnd, op_flags, &rc);
	+ if (error == 0)
	+ report_operation(attrs.rta_table, &rc, nlp, hdr);
	+ return (error);
	+}
	+
	+static int
	+path_match_func(const struct rtentry rt, const struct nhop_object nh, void *_data)
	+{
	+ struct nl_parsed_route attrs = (struct nl_parsed_route )_data;
	+
	+ if ((attrs->rta_gw != NULL) && !rib_match_gw(rt, nh, attrs->rta_gw))
	+ return (0);
	+
	+ if ((attrs->rta_oif != NULL) && (attrs->rta_oif != nh->nh_ifp))
	+ return (0);
	+
	+ return (1);
	+}
	+
	+static int
	+rtnl_handle_delroute(struct nlmsghdr hdr, struct nlpcb nlp,
	+ struct nl_pstate *npt)
	+{
	+ struct rib_cmd_info rc;
	+ int error;
	+
	+ struct nl_parsed_route attrs = {};
	+ error = nl_parse_nlmsg(hdr, &rtm_parser, npt, &attrs);
	+ if (error != 0)
	+ return (error);
	+
	+ if (attrs.rta_dst == NULL) {
	+ NLMSG_REPORT_ERR_MSG(npt, "RTA_DST is not set");
	+ return (ESRCH);
	+ }
	+
	+ error = rib_del_route_px(attrs.rta_table, attrs.rta_dst,
	+ attrs.rtm_dst_len, path_match_func, &attrs, 0, &rc);
	+ if (error == 0)
	+ report_operation(attrs.rta_table, &rc, nlp, hdr);
	+ return (error);
	+}
	+
	+static int
	+rtnl_handle_getroute(struct nlmsghdr hdr, struct nlpcb nlp, struct nl_pstate *npt)
	+{
	+ int error;
	+
	+ struct nl_parsed_route attrs = {};
	+ error = nl_parse_nlmsg(hdr, &rtm_parser, npt, &attrs);
	+ if (error != 0)
	+ return (error);
	+
	+ if (hdr->nlmsg_flags & NLM_F_DUMP)
	+ error = handle_rtm_dump(nlp, attrs.rta_table, attrs.rtm_family, hdr, npt->nw);
	+ else
	+ error = handle_rtm_getroute(nlp, &attrs, hdr, npt);
	+
	+ return (error);
	+}
	+
	+void
	+rtnl_handle_route_event(uint32_t fibnum, const struct rib_cmd_info *rc)
	+{
	+ int family, nlm_flags = 0;
	+
	+ struct nl_writer nw;
	+
	+ family = rt_get_family(rc->rc_rt);
	+
	+ /* XXX: check if there are active listeners first */
	+
	+ /* TODO: consider passing PID/type/seq */
	+ switch (rc->rc_cmd) {
	+ case RTM_ADD:
	+ nlm_flags = NLM_F_EXCL \| NLM_F_CREATE;
	+ break;
	+ case RTM_CHANGE:
	+ nlm_flags = NLM_F_REPLACE;
	+ break;
	+ case RTM_DELETE:
	+ nlm_flags = 0;
	+ break;
	+ }
	+ IF_DEBUG_LEVEL(LOG_DEBUG2) {
	+ char rtbuf[NHOP_PRINT_BUFSIZE] __unused;
	+ FIB_LOG(LOG_DEBUG2, fibnum, family,
	+ "received event %s for %s / nlm_flags=%X",
	+ rib_print_cmd(rc->rc_cmd),
	+ rt_print_buf(rc->rc_rt, rtbuf, sizeof(rtbuf)),
	+ nlm_flags);
	+ }
	+
	+ struct nlmsghdr hdr = {
	+ .nlmsg_flags = nlm_flags,
	+ .nlmsg_type = get_rtmsg_type_from_rtsock(rc->rc_cmd),
	+ };
	+
	+ struct route_nhop_data rnd = {
	+ .rnd_nhop = rc_get_nhop(rc),
	+ .rnd_weight = rc->rc_nh_weight,
	+ };
	+
	+ uint32_t group_id = family_to_group(family);
	+ if (!nlmsg_get_group_writer(&nw, NLMSG_SMALL, NETLINK_ROUTE, group_id)) {
	+ NL_LOG(LOG_DEBUG, "error allocating event buffer");
	+ return;
	+ }
	+
	+ dump_px(fibnum, &hdr, rc->rc_rt, &rnd, &nw);
	+ nlmsg_flush(&nw);
	+}
	+
	+static const struct rtnl_cmd_handler cmd_handlers[] = {
	+ {
	+ .cmd = NL_RTM_GETROUTE,
	+ .name = "RTM_GETROUTE",
	+ .cb = &rtnl_handle_getroute,
	+ },
	+ {
	+ .cmd = NL_RTM_DELROUTE,
	+ .name = "RTM_DELROUTE",
	+ .cb = &rtnl_handle_delroute,
	+ .priv = PRIV_NET_ROUTE,
	+ },
	+ {
	+ .cmd = NL_RTM_NEWROUTE,
	+ .name = "RTM_NEWROUTE",
	+ .cb = &rtnl_handle_newroute,
	+ .priv = PRIV_NET_ROUTE,
	+ }
	+};
	+
	+static const struct nlhdr_parser *all_parsers[] = {&mpath_parser, &metrics_parser, &rtm_parser};
	+
	+void
	+rtnl_routes_init()
	+{
	+ NL_VERIFY_PARSERS(all_parsers);
	+ rtnl_register_messages(cmd_handlers, NL_ARRAY_LEN(cmd_handlers));
	+}
	diff --git a/sys/netlink/route/route_var.h b/sys/netlink/route/route_var.h
	new file mode 100644
	--- /dev/null
	+++ b/sys/netlink/route/route_var.h
	@@ -0,0 +1,101 @@
	+/*-
	+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
	+ *
	+ * Copyright (c) 2022 Alexander V. Chernikov <melifaro@FreeBSD.org>
	+ *
	+ * Redistribution and use in source and binary forms, with or without
	+ * modification, are permitted provided that the following conditions
	+ * are met:
	+ * 1. Redistributions of source code must retain the above copyright
	+ * notice, this list of conditions and the following disclaimer.
	+ * 2. Redistributions in binary form must reproduce the above copyright
	+ * notice, this list of conditions and the following disclaimer in the
	+ * documentation and/or other materials provided with the distribution.
	+ *
	+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	+ * SUCH DAMAGE.
	+ */
	+
	+/*
	+ * This file contains definitions shared among NETLINK_ROUTE family
	+ */
	+#ifndef _NETLINK_ROUTE_ROUTE_VAR_H_
	+#define _NETLINK_ROUTE_ROUTE_VAR_H_
	+
	+#include <sys/priv.h> /* values for priv_check */
	+
	+struct nlmsghdr;
	+struct nlpcb;
	+struct nl_pstate;
	+
	+typedef int rtnl_msg_cb_f(struct nlmsghdr hdr, struct nlpcb nlp,
	+ struct nl_pstate *npt);
	+
	+struct rtnl_cmd_handler {
	+ int cmd;
	+ const char *name;
	+ rtnl_msg_cb_f *cb;
	+ int priv;
	+ int flags;
	+};
	+
	+#define RTNL_F_NOEPOCH 0x01
	+
	+bool rtnl_register_messages(const struct rtnl_cmd_handler *handlers, int count);
	+
	+/* route.c */
	+struct rib_cmd_info;
	+void rtnl_handle_route_event(uint32_t fibnum, const struct rib_cmd_info *rc);
	+void rtnl_routes_init(void);
	+
	+/* neigh.c */
	+void rtnl_neighs_init(void);
	+void rtnl_neighs_destroy(void);
	+
	+/* iface.c */
	+struct nl_parsed_link {
	+ char *ifla_group;
	+ char *ifla_ifname;
	+ char *ifla_cloner;
	+ struct nlattr *ifla_idata;
	+ unsigned short ifi_type;
	+ int ifi_index;
	+ uint32_t ifla_mtu;
	+};
	+
	+typedef int rtnl_iface_create_f(struct nl_parsed_link lattrs, struct nlpcb nlp,
	+ struct nl_pstate *npt);
	+typedef int rtnl_iface_modify_f(struct nl_parsed_link lattrs, struct nlpcb nlp,
	+ struct nl_pstate *npt);
	+
	+struct nl_cloner {
	+ const char *name;
	+ rtnl_iface_create_f *create_f;
	+ rtnl_iface_modify_f *modify_f;
	+ SLIST_ENTRY(nl_cloner) next;
	+};
	+
	+void rtnl_ifaces_init(void);
	+void rtnl_ifaces_destroy(void);
	+void rtnl_iface_add_cloner(struct nl_cloner *cloner);
	+void rtnl_iface_del_cloner(struct nl_cloner *cloner);
	+
	+/* iface_drivers.c */
	+void rtnl_iface_drivers_register(void);
	+
	+/* nexthop.c */
	+void rtnl_nexthops_init(void);
	+struct nhop_object *nl_find_nhop(uint32_t fibnum, int family,
	+ uint32_t uidx, int nh_flags, int *perror);
	+
	+
	+#endif
	diff --git a/tests/sys/net/routing/netlink.py b/tests/sys/net/routing/netlink.py
	new file mode 100644
	--- /dev/null
	+++ b/tests/sys/net/routing/netlink.py
	@@ -0,0 +1,1167 @@
	+#!/usr/local/bin/python3
	+
	+from ctypes import *
	+import socket
	+import os
	+import sys
	+import unittest
	+import struct
	+
	+from enum import Enum, auto
	+
	+from typing import List, Callable, Dict, NamedTuple, Optional
	+
	+
	+def roundup2(val: int, num: int) -> int:
	+ if val % num:
	+ return (val \| (num - 1)) + 1
	+ else:
	+ return val
	+
	+
	+def align4(val: int) -> int:
	+ return roundup2(val, 4)
	+
	+
	+class SockaddrNl(Structure):
	+ _fields_ = [
	+ ("nl_len", c_ubyte),
	+ ("nl_family", c_ubyte),
	+ ("nl_pad", c_ushort),
	+ ("nl_pid", c_uint),
	+ ("nl_groups", c_uint),
	+ ]
	+
	+
	+class Nlmsghdr(Structure):
	+ _fields_ = [
	+ ("nlmsg_len", c_uint),
	+ ("nlmsg_type", c_ushort),
	+ ("nlmsg_flags", c_ushort),
	+ ("nlmsg_seq", c_uint),
	+ ("nlmsg_pid", c_uint),
	+ ]
	+
	+
	+class Nlmsgerr(Structure):
	+ _fields_ = [
	+ ("error", c_int),
	+ ("msg", Nlmsghdr),
	+ ]
	+
	+
	+class NlErrattrType(Enum):
	+ NLMSGERR_ATTR_UNUSED = 0
	+ NLMSGERR_ATTR_MSG = auto()
	+ NLMSGERR_ATTR_OFFS = auto()
	+ NLMSGERR_ATTR_COOKIE = auto()
	+ NLMSGERR_ATTR_POLICY = auto()
	+
	+class RtattrType(Enum):
	+ RTA_UNSPEC = 0
	+ RTA_DST = auto()
	+ RTA_SRC = auto()
	+ RTA_IIF = auto()
	+ RTA_OIF = auto()
	+ RTA_GATEWAY = auto()
	+ RTA_PRIORITY = auto()
	+ RTA_PREFSRC = auto()
	+ RTA_METRICS = auto()
	+ RTA_MULTIPATH = auto()
	+ RTA_PROTOINFO = auto()
	+ RTA_FLOW = auto()
	+ RTA_CACHEINFO = auto()
	+ RTA_SESSION = auto()
	+ RTA_MP_ALGO = auto()
	+ RTA_TABLE = auto()
	+ RTA_MARK = auto()
	+ RTA_MFC_STATS = auto()
	+ RTA_VIA = auto()
	+ RTA_NEWDST = auto()
	+ RTA_PREF = auto()
	+ RTA_ENCAP_TYPE = auto()
	+ RTA_ENCAP = auto()
	+ RTA_EXPIRES = auto()
	+ RTA_PAD = auto()
	+ RTA_UID = auto()
	+ RTA_TTL_PROPAGATE = auto()
	+ RTA_IP_PROTO = auto()
	+ RTA_SPORT = auto()
	+ RTA_DPORT = auto()
	+ RTA_NH_ID = auto()
	+
	+
	+class NlMsgType(Enum):
	+ NLMSG_NOOP = 1
	+ NLMSG_ERROR = 2
	+ NLMSG_DONE = 3
	+ NLMSG_OVERRUN = 4
	+
	+
	+class NlRtMsgType(Enum):
	+ RTM_NEWLINK = 16
	+ RTM_DELLINK = 17
	+ RTM_GETLINK = 18
	+ RTM_SETLINK = 19
	+ RTM_NEWADDR = 20
	+ RTM_DELADDR = 21
	+ RTM_GETADDR = 22
	+ RTM_NEWROUTE = 24
	+ RTM_DELROUTE = 25
	+ RTM_GETROUTE = 26
	+ RTM_NEWNEIGH = 28
	+ RTM_DELNEIGH = 27
	+ RTM_GETNEIGH = 28
	+ RTM_NEWRULE = 32
	+ RTM_DELRULE = 33
	+ RTM_GETRULE = 34
	+ RTM_NEWQDISC = 36
	+ RTM_DELQDISC = 37
	+ RTM_GETQDISC = 38
	+ RTM_NEWTCLASS = 40
	+ RTM_DELTCLASS = 41
	+ RTM_GETTCLASS = 42
	+ RTM_NEWTFILTER = 44
	+ RTM_DELTFILTER = 45
	+ RTM_GETTFILTER = 46
	+ RTM_NEWACTION = 48
	+ RTM_DELACTION = 49
	+ RTM_GETACTION = 50
	+ RTM_NEWPREFIX = 52
	+ RTM_GETMULTICAST = 58
	+ RTM_GETANYCAST = 62
	+ RTM_NEWNEIGHTBL = 64
	+ RTM_GETNEIGHTBL = 66
	+ RTM_SETNEIGHTBL = 67
	+ RTM_NEWNDUSEROPT = 68
	+ RTM_NEWADDRLABEL = 72
	+ RTM_DELADDRLABEL = 73
	+ RTM_GETADDRLABEL = 74
	+ RTM_GETDCB = 78
	+ RTM_SETDCB = 79
	+ RTM_NEWNETCONF = 80
	+ RTM_GETNETCONF = 82
	+ RTM_NEWMDB = 84
	+ RTM_DELMDB = 85
	+ RTM_GETMDB = 86
	+ RTM_NEWNSID = 88
	+ RTM_DELNSID = 89
	+ RTM_GETNSID = 90
	+ RTM_NEWSTATS = 92
	+ RTM_GETSTATS = 94
	+
	+
	+class RtAttr(Structure):
	+ _fields_ = [
	+ ("rta_len", c_ushort),
	+ ("rta_type", c_ushort),
	+ ]
	+
	+
	+class RtMsgHdr(Structure):
	+ _fields_ = [
	+ ("rtm_family", c_ubyte),
	+ ("rtm_dst_len", c_ubyte),
	+ ("rtm_src_len", c_ubyte),
	+ ("rtm_tos", c_ubyte),
	+ ("rtm_table", c_ubyte),
	+ ("rtm_protocol", c_ubyte),
	+ ("rtm_scope", c_ubyte),
	+ ("rtm_type", c_ubyte),
	+ ("rtm_flags", c_uint),
	+ ]
	+
	+
	+class RtMsgFlags(Enum):
	+ RTM_F_NOTIFY = 0x100
	+ RTM_F_CLONED = 0x200
	+ RTM_F_EQUALIZE = 0x400
	+ RTM_F_PREFIX = 0x800
	+ RTM_F_LOOKUP_TABLE = 0x1000
	+ RTM_F_FIB_MATCH = 0x2000
	+ RTM_F_OFFLOAD = 0x4000
	+ RTM_F_TRAP = 0x8000
	+ RTM_F_OFFLOAD_FAILED = 0x20000000
	+
	+
	+class AddressFamilyLinux(Enum):
	+ AF_INET = socket.AF_INET
	+ AF_INET6 = socket.AF_INET6
	+ AF_NETLINK = 16
	+
	+
	+class AddressFamilyBsd(Enum):
	+ AF_INET = socket.AF_INET
	+ AF_INET6 = socket.AF_INET6
	+ AF_NETLINK = 38
	+
	+
	+class NlmBaseFlags(Enum):
	+ NLM_F_REQUEST = 0x01
	+ NLM_F_MULTI = 0x02
	+ NLM_F_ACK = 0x04
	+ NLM_F_ECHO = 0x08
	+ NLM_F_DUMP_INTR = 0x10
	+ NLM_F_DUMP_FILTERED = 0x20
	+
	+# XXX: in python3.8 it is possible to
	+# class NlmGetFlags(Enum, NlmBaseFlags):
	+
	+
	+class NlmGetFlags(Enum):
	+ NLM_F_ROOT = 0x100
	+ NLM_F_MATCH = 0x200
	+ NLM_F_ATOMIC = 0x400
	+
	+
	+class NlmNewFlags(Enum):
	+ NLM_F_REPLACE = 0x100
	+ NLM_F_EXCL = 0x200
	+ NLM_F_CREATE = 0x400
	+ NLM_F_APPEND = 0x800
	+
	+
	+class NlmDeleteFlags(Enum):
	+ NLM_F_NONREC = 0x100
	+
	+
	+class NlmAckFlags(Enum):
	+ NLM_F_CAPPED = 0x100
	+ NLM_F_ACK_TLVS = 0x200
	+
	+
	+class RtScope(Enum):
	+ RT_SCOPE_UNIVERSE = 0
	+ RT_SCOPE_SITE = 200
	+ RT_SCOPE_LINK = 253
	+ RT_SCOPE_HOST = 254
	+ RT_SCOPE_NOWHERE = 255
	+
	+
	+class RtType(Enum):
	+ RTN_UNSPEC = 0
	+ RTN_UNICAST = auto()
	+ RTN_LOCAL = auto()
	+ RTN_BROADCAST = auto()
	+ RTN_ANYCAST = auto()
	+ RTN_MULTICAST = auto()
	+ RTN_BLACKHOLE = auto()
	+ RTN_UNREACHABLE = auto()
	+ RTN_PROHIBIT = auto()
	+ RTN_THROW = auto()
	+ RTN_NAT = auto()
	+ RTN_XRESOLVE = auto()
	+
	+
	+class RtProto(Enum):
	+ RTPROT_UNSPEC = 0
	+ RTPROT_REDIRECT = 1
	+ RTPROT_KERNEL = 2
	+ RTPROT_BOOT = 3
	+ RTPROT_STATIC = 4
	+ RTPROT_GATED = 8
	+ RTPROT_RA = 9
	+ RTPROT_MRT = 10
	+ RTPROT_ZEBRA = 11
	+ RTPROT_BIRD = 12
	+ RTPROT_DNROUTED = 13
	+ RTPROT_XORP = 14
	+ RTPROT_NTK = 15
	+ RTPROT_DHCP = 16
	+ RTPROT_MROUTED = 17
	+ RTPROT_KEEPALIVED = 18
	+ RTPROT_BABEL = 42
	+ RTPROT_OPENR = 99
	+ RTPROT_BGP = 186
	+ RTPROT_ISIS = 187
	+ RTPROT_OSPF = 188
	+ RTPROT_RIP = 189
	+ RTPROT_EIGRP = 192
	+
	+
	+class NlRtaxType(Enum):
	+ RTAX_UNSPEC = 0
	+ RTAX_LOCK = auto()
	+ RTAX_MTU = auto()
	+ RTAX_WINDOW = auto()
	+ RTAX_RTT = auto()
	+ RTAX_RTTVAR = auto()
	+ RTAX_SSTHRESH = auto()
	+ RTAX_CWND = auto()
	+ RTAX_ADVMSS = auto()
	+ RTAX_REORDERING = auto()
	+ RTAX_HOPLIMIT = auto()
	+ RTAX_INITCWND = auto()
	+ RTAX_FEATURES = auto()
	+ RTAX_RTO_MIN = auto()
	+ RTAX_INITRWND = auto()
	+ RTAX_QUICKACK = auto()
	+ RTAX_CC_ALGO = auto()
	+ RTAX_FASTOPEN_NO_COOKIE = auto()
	+
	+
	+class NlRtGroup(Enum):
	+ RTNLGRP_NONE = 0
	+ RTNLGRP_LINK = auto()
	+ RTNLGRP_NOTIFY = auto()
	+ RTNLGRP_NEIGH = auto()
	+ RTNLGRP_TC = auto()
	+ RTNLGRP_IPV4_IFADDR = auto()
	+ RTNLGRP_IPV4_MROUTE = auto()
	+ RTNLGRP_IPV4_ROUTE = auto()
	+ RTNLGRP_IPV4_RULE = auto()
	+ RTNLGRP_IPV6_IFADDR = auto()
	+ RTNLGRP_IPV6_MROUTE = auto()
	+ RTNLGRP_IPV6_ROUTE = auto()
	+ RTNLGRP_IPV6_IFINFO = auto()
	+ RTNLGRP_DECnet_IFADDR = auto()
	+ RTNLGRP_NOP2 = auto()
	+ RTNLGRP_DECnet_ROUTE = auto()
	+ RTNLGRP_DECnet_RULE = auto()
	+ RTNLGRP_NOP4 = auto()
	+ RTNLGRP_IPV6_PREFIX = auto()
	+ RTNLGRP_IPV6_RULE = auto()
	+ RTNLGRP_ND_USEROPT = auto()
	+ RTNLGRP_PHONET_IFADDR = auto()
	+ RTNLGRP_PHONET_ROUTE = auto()
	+ RTNLGRP_DCB = auto()
	+ RTNLGRP_IPV4_NETCONF = auto()
	+ RTNLGRP_IPV6_NETCONF = auto()
	+ RTNLGRP_MDB = auto()
	+ RTNLGRP_MPLS_ROUTE = auto()
	+ RTNLGRP_NSID = auto()
	+ RTNLGRP_MPLS_NETCONF = auto()
	+ RTNLGRP_IPV4_MROUTE_R = auto()
	+ RTNLGRP_IPV6_MROUTE_R = auto()
	+ RTNLGRP_NEXTHOP = auto()
	+ RTNLGRP_BRVLAN = auto()
	+
	+
	+class IfinfoMsg(Structure):
	+ _fields_ = [
	+ ("ifi_family", c_ubyte),
	+ ("__ifi_pad", c_ubyte),
	+ ("ifi_type", c_ushort),
	+ ("ifi_index", c_int),
	+ ("ifi_flags", c_uint),
	+ ("ifi_change", c_uint),
	+ ]
	+
	+
	+class IflattrType(Enum):
	+ IFLA_UNSPEC = 0
	+ IFLA_ADDRESS = auto()
	+ IFLA_BROADCAST = auto()
	+ IFLA_IFNAME = auto()
	+ IFLA_MTU = auto()
	+ IFLA_LINK = auto()
	+ IFLA_QDISC = auto()
	+ IFLA_STATS = auto()
	+ IFLA_COST = auto()
	+ IFLA_PRIORITY = auto()
	+ IFLA_MASTER = auto()
	+ IFLA_WIRELESS = auto()
	+ IFLA_PROTINFO = auto()
	+ IFLA_TXQLEN = auto()
	+ IFLA_MAP = auto()
	+ IFLA_WEIGHT = auto()
	+ IFLA_OPERSTATE = auto()
	+ IFLA_LINKMODE = auto()
	+ IFLA_LINKINFO = auto()
	+ IFLA_NET_NS_PID = auto()
	+ IFLA_IFALIAS = auto()
	+ IFLA_NUM_VF = auto()
	+ IFLA_VFINFO_LIST = auto()
	+ IFLA_STATS64 = auto()
	+ IFLA_VF_PORTS = auto()
	+ IFLA_PORT_SELF = auto()
	+ IFLA_AF_SPEC = auto()
	+ IFLA_GROUP = auto()
	+ IFLA_NET_NS_FD = auto()
	+ IFLA_EXT_MASK = auto()
	+ IFLA_PROMISCUITY = auto()
	+ IFLA_NUM_TX_QUEUES = auto()
	+ IFLA_NUM_RX_QUEUES = auto()
	+ IFLA_CARRIER = auto()
	+ IFLA_PHYS_PORT_ID = auto()
	+ IFLA_CARRIER_CHANGES = auto()
	+ IFLA_PHYS_SWITCH_ID = auto()
	+ IFLA_LINK_NETNSID = auto()
	+ IFLA_PHYS_PORT_NAME = auto()
	+ IFLA_PROTO_DOWN = auto()
	+ IFLA_GSO_MAX_SEGS = auto()
	+ IFLA_GSO_MAX_SIZE = auto()
	+ IFLA_PAD = auto()
	+ IFLA_XDP = auto()
	+ IFLA_EVENT = auto()
	+ IFLA_NEW_NETNSID = auto()
	+ IFLA_IF_NETNSID = auto()
	+ IFLA_CARRIER_UP_COUNT = auto()
	+ IFLA_CARRIER_DOWN_COUNT = auto()
	+ IFLA_NEW_IFINDEX = auto()
	+ IFLA_MIN_MTU = auto()
	+ IFLA_MAX_MTU = auto()
	+ IFLA_PROP_LIST = auto()
	+ IFLA_ALT_IFNAME = auto()
	+ IFLA_PERM_ADDRESS = auto()
	+ IFLA_PROTO_DOWN_REASON = auto()
	+
	+
	+class IfaddrMsg(Structure):
	+ _fields_ = [
	+ ("ifa_family", c_ubyte),
	+ ("ifa_prefixlen", c_ubyte),
	+ ("ifa_flags", c_ubyte),
	+ ("ifa_scope", c_ubyte),
	+ ("ifa_index", c_uint),
	+ ]
	+
	+
	+class IfattrType(Enum):
	+ IFA_UNSPEC = 0
	+ IFA_ADDRESS = auto()
	+ IFA_LOCAL = auto()
	+ IFA_LABEL = auto()
	+ IFA_BROADCAST = auto()
	+ IFA_ANYCAST = auto()
	+ IFA_CACHEINFO = auto()
	+ IFA_MULTICAST = auto()
	+ IFA_FLAGS = auto()
	+ IFA_RT_PRIORITY = auto()
	+ IFA_TARGET_NETNSID = auto()
	+
	+
	+class GenlMsgHdr(Structure):
	+ _fields_ = [
	+ ("cmd", c_ubyte),
	+ ("version", c_ubyte),
	+ ("reserved", c_ushort),
	+ ]
	+
	+
	+class NlConst():
	+ AF_NETLINK = 38
	+ NETLINK_ROUTE = 0
	+ NETLINK_GENERIC = 16
	+
	+
	+class NlHelper():
	+ def __init__(self):
	+ self._pmap = {}
	+ self._af_cls = self.get_af_cls()
	+
	+ def get_af_cls(self):
	+ if sys.platform.startswith("freebsd"):
	+ cls = AddressFamilyBsd
	+ else:
	+ cls = AddressFamilyLinux
	+ return cls
	+
	+ def get_propmap(self, cls):
	+ if cls not in self._pmap:
	+ ret = {}
	+ for prop in dir(cls):
	+ if not prop.startswith("_"):
	+ ret[getattr(cls, prop).value] = prop
	+ self._pmap[cls] = ret
	+ return self._pmap[cls]
	+
	+ def get_name_propmap(self, cls):
	+ ret = {}
	+ for prop in dir(cls):
	+ if not prop.startswith("_"):
	+ ret[prop] = getattr(cls, prop).value
	+ return ret
	+
	+ def get_attr_byval(self, cls, attr_val):
	+ propmap = self.get_propmap(cls)
	+ return propmap.get(attr_val)
	+
	+ def get_nlmsg_name(self, val):
	+ for cls in [NlRtMsgType, NlMsgType]:
	+ v = self.get_attr_byval(cls, val)
	+ if v is not None:
	+ return v
	+ return "msg#{}".format(val)
	+
	+ def get_af_name(self, family):
	+ v = self.get_attr_byval(self._af_cls, family)
	+ if v is not None:
	+ return v
	+ return "af#{}".format(family)
	+
	+ def get_af_value(self, family_str: str) -> int:
	+ propmap = self.get_name_propmap(self._af_cls)
	+ return propmap.get(family_str)
	+
	+ def get_rta_name(self, val):
	+ return self.get_attr_byval(RtattrType, val)
	+
	+ def get_bitmask_map(self, cls, val):
	+ propmap = self.get_propmap(cls)
	+ v = 1
	+ ret = {}
	+ while val:
	+ if v & val:
	+ if v in propmap:
	+ ret[v] = propmap[v]
	+ else:
	+ ret[v] = hex(v)
	+ val -= v
	+ v *= 2
	+ return ret
	+
	+ def get_bitmask_str(self, cls, val):
	+ bmap = self.get_bitmask_map(cls, val)
	+ return ",".join([v for k, v in bmap.items()])
	+
	+ def get_nlm_flags_str(self, msg_str: str, reply: bool, val):
	+ if reply:
	+ return self.get_bitmask_str(NlmAckFlags, val)
	+ if msg_str.startswith("RTM_GET"):
	+ return self.get_bitmask_str(NlmGetFlags, val)
	+ elif msg_str.startswith("RTM_DEL"):
	+ return self.get_bitmask_str(NlmDeleteFlags, val)
	+ elif msg_str.startswith("RTM_NEW"):
	+ return self.get_bitmask_str(NlmNewFlags, val)
	+ else:
	+ return self.get_bitmask_str(NlmBaseFlags, val)
	+
	+
	+class BaseRtAttr(object):
	+ def __init__(self, parent, rta_type, rta_len, data=None):
	+ self.parent = parent
	+ self.helper = parent.helper
	+ self.attr_enum = parent.attr_enum
	+ self.rta_type = rta_type & 0x3f
	+ self.is_nested = rta_type & (1 << 15)
	+ self.network_byte_order = rta_type & (1 << 14)
	+ self.rta_len = rta_len
	+ self.rta_type_str = self.helper.get_attr_byval(self.attr_enum, self.rta_type) # noqa: E501
	+ if data is not None:
	+ self._validate(data)
	+ self._parse(data)
	+ self._orig_data = data
	+
	+ def print_attribute(self, prepend=""):
	+ if self.rta_type_str:
	+ type_str = self.rta_type_str
	+ else:
	+ type_str = "rta#{}".format(self.rta_type)
	+ print("{}rta_len={} rta_type={}({}){}".format(prepend,
	+ self.rta_len,
	+ type_str,
	+ self.rta_type,
	+ self._print_attr_value())
	+ )
	+
	+ def _print_attr_value(self):
	+ return " [" + " ".join(["{:02X}".format(b) for b in self._orig_data[4:]]) + "]" # noqa: E501
	+
	+ @classmethod
	+ def from_bytes(cls, parent, data):
	+ if len(data) < sizeof(RtAttr):
	+ raise ValueError("length less than rtattr header")
	+ rta_hdr = RtAttr.from_buffer_copy(data)
	+ self = cls(parent, rta_hdr.rta_type, rta_hdr.rta_len, data[:rta_hdr.rta_len]) # noqa: E501
	+ # XXX: nested
	+ return self
	+
	+ def __bytes__(self):
	+ ret = self._orig_data
	+ if align4(len(ret)) != len(ret):
	+ ret += bytes(align4(len(ret)) - len(ret))
	+ return ret
	+
	+ def _validate(self, data):
	+ pass
	+
	+ def _parse(self, data):
	+ pass
	+
	+
	+class RtAttrIp(BaseRtAttr):
	+ def _validate(self, data):
	+ data_len = len(data) - 4
	+ if data_len != 4 and data_len != 16:
	+ raise ValueError("Error validating attr {}: rta_len is not valid".format( # noqa: E501
	+ self.rta_type_str))
	+
	+ def _parse(self, data):
	+ data_len = len(data) - 4
	+ if data_len == 4:
	+ self.family = socket.AF_INET
	+ self.addr = socket.inet_ntop(self.family, data[4:8])
	+ else:
	+ self.family = socket.AF_INET6
	+ self.addr = socket.inet_ntop(self.family, data[4:20])
	+
	+ def _print_attr_value(self):
	+ return " addr={}".format(self.addr)
	+
	+
	+class RtAttrU32(BaseRtAttr):
	+ def _validate(self, data):
	+ if len(data) != 8:
	+ raise ValueError("Error validating attr {}: rta_len is not valid".format( # noqa: E501
	+ self.rta_type_str))
	+
	+ def _parse(self, data):
	+ self.value = struct.unpack("@I", data[4:8])[0]
	+
	+ def _print_attr_value(self):
	+ return " value={}".format(self.value)
	+
	+
	+class RtAttrIfindex(RtAttrU32):
	+ def _print_attr_value(self):
	+ try:
	+ ifname = socket.if_indextoname(self.value)
	+ return " iface={}(#{})".format(ifname, self.value)
	+ except OSError as e:
	+ pass
	+ return " iface=if#{}".format(self.value)
	+
	+
	+class RtAttrTable(RtAttrU32):
	+ def _print_attr_value(self):
	+ return " rtable={}".format(self.value)
	+
	+
	+class RtAttrNhId(RtAttrU32):
	+ def _print_attr_value(self):
	+ return " nh_id={}".format(self.value)
	+
	+
	+class RtAttrVia(BaseRtAttr):
	+ def _validate(self, data):
	+ data_len = len(data) - 4
	+ if data_len == 0:
	+ raise ValueError("Error validating attr {}: empty data".format(self.rta_type_str)) # noqa: E501
	+ family = int(data_len[0])
	+ if family not in (socket.AF_INET, socket.AF_INET6):
	+ raise ValueError("Error validating attr {}: unsupported AF {}".format( # noqa: E501
	+ self.rta_type_str, family))
	+ if family == socket.AF_INET:
	+ expected_len = 1 + 4
	+ else:
	+ expected_len = 1 + 16
	+ if data_len != expected_len:
	+ raise ValueError("Error validating attr {}: expected len {} got {}".format( # noqa: E501
	+ self.rta_type_str, expected_len, data_len))
	+
	+ def _parse(self, data):
	+ data_len = len(data) - 4
	+ self.family = int(data_len[0])
	+ if self.family == socket.AF_INET:
	+ self.addr = socket.inet_ntop(self.family, data[5:9])
	+ else:
	+ self.addr = socket.inet_ntop(self.family, data[5:21])
	+
	+ def _print_attr_value(self):
	+ return ", via={}".format(self.addr)
	+
	+
	+class RtAttrStr(BaseRtAttr):
	+ def _validate(self, data):
	+ try:
	+ s = data[4:].decode("utf-8")
	+ except Exception as e:
	+ raise ValueError("wrong utf-8 string")
	+
	+ def _parse(self, data):
	+ self.str = data[4:].decode("utf-8")
	+
	+ def _print_attr_value(self):
	+ return " str=\"{}\"".format(self.str)
	+
	+
	+rta_class_map = {
	+ "RTA_DST": RtAttrIp,
	+ "RTA_SRC": RtAttrIp,
	+ "RTA_IIF": RtAttrIfindex,
	+ "RTA_OIF": RtAttrIfindex,
	+ "RTA_GATEWAY": RtAttrIp,
	+ "RTA_TABLE": RtAttrTable,
	+ "RTA_VIA": RtAttrVia,
	+ "RTA_NH_ID": RtAttrNhId,
	+}
	+
	+err_class_map = {
	+ "NLMSGERR_ATTR_MSG": RtAttrStr,
	+ "NLMSGERR_ATTR_OFFS": RtAttrU32,
	+}
	+
	+ifla_class_map = {
	+ "IFLA_MTU": RtAttrU32,
	+}
	+
	+ifa_class_map = {
	+ "IFA_ADDRESS": RtAttrIp,
	+ "IFA_LOCAL": RtAttrIp,
	+ "IFA_LABEL": RtAttrStr,
	+ "IFA_BROADCAST": RtAttrIp,
	+ "IFA_ANYCAST": RtAttrIp,
	+ "IFA_FLAGS": RtAttrU32,
	+}
	+
	+
	+class BaseNetlinkMessage(object):
	+ def __init__(self, helper, nlmsg_type):
	+ self.nlmsg_type = nlmsg_type
	+ self.ut = unittest.TestCase()
	+ self.nla_list = []
	+ self._orig_data = None
	+ self.helper = helper
	+ self.nl_hdr = Nlmsghdr(nlmsg_type=nlmsg_type)
	+
	+ def assertEqual(self, a, b, msg=None):
	+ self.ut.assertEqual(a, b, msg)
	+
	+ def assertNotEqual(self, a, b, msg=None):
	+ self.ut.assertNotEqual(a, b, msg)
	+
	+ @staticmethod
	+ def parse_nl_header(data: bytes):
	+ if len(data) < sizeof(Nlmsghdr):
	+ raise ValueError("length less than netlink message header")
	+ return Nlmsghdr.from_buffer_copy(data), sizeof(Nlmsghdr)
	+
	+ def is_reply(self, hdr):
	+ return hdr.nlmsg_type == NlMsgType.NLMSG_ERROR.value
	+
	+ def print_nl_header(self, hdr, prepend=""):
	+ # len=44, type=RTM_DELROUTE, flags=NLM_F_REQUEST\|NLM_F_ACK, seq=1641163704, pid=0 # noqa: E501
	+ is_reply = self.is_reply(hdr)
	+ msg_name = self.helper.get_nlmsg_name(hdr.nlmsg_type)
	+ print("{}len={}, type={}, flags={}(0x{:X}), seq={}, pid={}".format(
	+ prepend,
	+ hdr.nlmsg_len,
	+ msg_name,
	+ self.helper.get_nlm_flags_str(msg_name, is_reply, hdr.nlmsg_flags), # noqa: E501
	+ hdr.nlmsg_flags,
	+ hdr.nlmsg_seq,
	+ hdr.nlmsg_pid
	+ ))
	+
	+ @classmethod
	+ def from_bytes(cls, helper, data):
	+ try:
	+ hdr, hdrlen = BaseNetlinkMessage.parse_nl_header(data)
	+ self = cls(helper, hdr.nlmsg_type)
	+ self._orig_data = data
	+ self.nl_hdr = hdr
	+ except ValueError as e:
	+ print("Failed to parse nl header: {}".format(e))
	+ cls.print_as_bytes(data)
	+ raise
	+ return self
	+
	+ def print_message(self):
	+ self.print_nl_header(self.nl_hdr)
	+
	+ @staticmethod
	+ def print_as_bytes(data: bytes, descr: str):
	+ print("===vv {} (len:{:3d}) vv===".format(descr, len(data)))
	+ off = 0
	+ step = 16
	+ while off < len(data):
	+ for i in range(step):
	+ if off + i < len(data):
	+ print(" {:02X}".format(data[off + i]), end="")
	+ print("")
	+ off += step
	+ print("--------------------")
	+
	+
	+class StdNetlinkMessage(BaseNetlinkMessage):
	+ @classmethod
	+ def from_bytes(cls, helper, data):
	+ try:
	+ hdr, hdrlen = BaseNetlinkMessage.parse_nl_header(data)
	+ self = cls(helper, hdr.nlmsg_type)
	+ self._orig_data = data
	+ self.nl_hdr = hdr
	+ except ValueError as e:
	+ print("Failed to parse nl header: {}".format(e))
	+ cls.print_as_bytes(data)
	+ raise
	+
	+ offset = align4(hdrlen)
	+ try:
	+ base_hdr, hdrlen = self.parse_base_header(data[offset:])
	+ self.base_hdr = base_hdr
	+ offset += align4(hdrlen)
	+ ## XXX: CAP_ACK
	+ except ValueError as e:
	+ print("Failed to parse nl rt header: {}".format(e))
	+ cls.print_as_bytes(data)
	+ raise
	+
	+ orig_offset = offset
	+ try:
	+ nla_list, nla_len = self.parse_nla_list(data[offset:])
	+ offset += nla_len
	+ if offset != len(data):
	+ raise ValueError("{} bytes left at the end of the packet".format(len(data) - offset)) # noqa: E501
	+ self.nla_list = nla_list
	+ except ValueError as e:
	+ print("Failed to parse nla attributes at offset {}: {}".format(orig_offset, e)) # noqa: E501
	+ cls.print_as_bytes(data, "msg dump")
	+ cls.print_as_bytes(data[orig_offset:], "failed block")
	+ raise
	+ return self
	+
	+ def parse_nla_list(self, data: bytes) -> List[BaseRtAttr]:
	+ ret = []
	+ offset = 0
	+ while offset < len(data):
	+ # print("OFFSET={}".format(offset))
	+ if offset + 4 > len(data):
	+ raise ValueError("only {} bytes remaining".format(len(data) - offset)) # noqa: E501
	+ rta_hdr = RtAttr.from_buffer_copy(data[offset:])
	+ rta_type_str = self.helper.get_attr_byval(self.attr_enum, rta_hdr.rta_type) # noqa: E501
	+ cls = self.attr_class_map.get(rta_type_str, BaseRtAttr)
	+ rta = cls.from_bytes(self, data[offset:])
	+ offset += align4(rta.rta_len)
	+ if rta.rta_len == 0:
	+ raise ValueError("empty rta len, {} bytes remaining".format(len(data) - offset)) # noqa: E501
	+ ret.append(rta)
	+ return ret, offset
	+
	+ def print_message(self):
	+ self.print_nl_header(self.nl_hdr)
	+ self.print_base_header(self.base_hdr, " ")
	+ for nla in self.nla_list:
	+ nla.print_attribute(" ")
	+
	+
	+class NetlinkErrorMessage(StdNetlinkMessage):
	+ messages = [NlMsgType.NLMSG_ERROR.value]
	+ attr_class_map = err_class_map
	+ attr_enum = NlErrattrType
	+
	+ def __init__(self, helper, nlmsg_type):
	+ super().__init__(helper, nlmsg_type)
	+ self.err_hdr = Nlmsgerr()
	+
	+ def parse_base_header(self, data):
	+ if len(data) < sizeof(Nlmsgerr):
	+ raise ValueError("length less than nlmsgerr header")
	+ err_hdr = Nlmsgerr.from_buffer_copy(data)
	+ sz = sizeof(Nlmsgerr)
	+ if (self.nl_hdr.nlmsg_flags & 0x100) == 0:
	+ sz += align4(err_hdr.msg.nlmsg_len - sizeof(Nlmsghdr))
	+ return (err_hdr, sz)
	+
	+ def print_base_header(self, errhdr, prepend=""):
	+ print("{}error={}, ".format(prepend, errhdr.error), end="")
	+ self.print_nl_header(errhdr.msg, prepend)
	+
	+
	+class BaseNetlinkRtMessage(StdNetlinkMessage):
	+ attr_class_map = {}
	+ attr_enum = None
	+
	+ def __init__(self, helper, nlm_type):
	+ super().__init__(helper, nlm_type)
	+ self.base_hdr = None
	+
	+ def __bytes__(self):
	+ ret = bytes()
	+ for nla in self.nla_list:
	+ ret += bytes(nla)
	+ ret = bytes(self.base_hdr) + ret
	+ self.nl_hdr.nlmsg_len = len(ret) + sizeof(Nlmsghdr)
	+ return bytes(self.nl_hdr) + ret
	+
	+ def print_message(self):
	+ self.print_nl_header(self.nl_hdr)
	+ self.print_base_header(self.base_hdr, " ")
	+ for nla in self.nla_list:
	+ nla.print_attribute(" ")
	+
	+
	+class NetlinkRtMessage(BaseNetlinkRtMessage):
	+ messages = [
	+ NlRtMsgType.RTM_NEWROUTE.value,
	+ NlRtMsgType.RTM_DELROUTE.value,
	+ NlRtMsgType.RTM_GETROUTE.value,
	+ ]
	+ attr_class_map = rta_class_map
	+ attr_enum = RtattrType
	+
	+ def __init__(self, helper, nlm_type):
	+ super().__init__(helper, nlm_type)
	+ self.base_hdr = RtMsgHdr()
	+
	+ def parse_base_header(self, data):
	+ if len(data) < sizeof(RtMsgHdr):
	+ raise ValueError("length less than rtmsg header")
	+ rtm_hdr = RtMsgHdr.from_buffer_copy(data)
	+ return (rtm_hdr, sizeof(RtMsgHdr))
	+
	+ def print_base_header(self, hdr, prepend=""):
	+ family = self.helper.get_af_name(hdr.rtm_family)
	+ print("{}family={}, dst_len={}, src_len={}, tos={}, table={}, protocol={}({}), scope={}({}), type={}({}), flags={}({})".format( # noqa: E501
	+ prepend,
	+ family,
	+ hdr.rtm_dst_len,
	+ hdr.rtm_src_len,
	+ hdr.rtm_tos,
	+ hdr.rtm_table,
	+ self.helper.get_attr_byval(RtProto, hdr.rtm_protocol),
	+ hdr.rtm_protocol,
	+ self.helper.get_attr_byval(RtScope, hdr.rtm_scope),
	+ hdr.rtm_scope,
	+ self.helper.get_attr_byval(RtType, hdr.rtm_type),
	+ hdr.rtm_type,
	+ self.helper.get_bitmask_str(RtMsgFlags, hdr.rtm_flags),
	+ hdr.rtm_flags))
	+
	+
	+class NetlinkIflaMessage(BaseNetlinkRtMessage):
	+ messages = [
	+ NlRtMsgType.RTM_NEWLINK.value,
	+ NlRtMsgType.RTM_DELLINK.value,
	+ NlRtMsgType.RTM_GETLINK.value,
	+ ]
	+ attr_class_map = ifla_class_map
	+ attr_enum = IflattrType
	+
	+ def __init__(self, helper, nlm_type):
	+ super().__init__(helper, nlm_type)
	+ self.base_hdr = IfinfoMsg()
	+
	+ def parse_base_header(self, data):
	+ if len(data) < sizeof(IfinfoMsg):
	+ raise ValueError("length less than IfinfoMsg header")
	+ rtm_hdr = IfinfoMsg.from_buffer_copy(data)
	+ return (rtm_hdr, sizeof(IfinfoMsg))
	+
	+ def print_base_header(self, hdr, prepend=""):
	+ family = self.helper.get_af_name(hdr.ifi_family)
	+ print("{}family={}, ifi_type={}, ifi_index={}, ifi_flags={}, ifi_change={}".format( # noqa: E501
	+ prepend,
	+ family,
	+ hdr.ifi_type,
	+ hdr.ifi_index,
	+ hdr.ifi_flags,
	+ hdr.ifi_change))
	+
	+
	+class NetlinkIfaMessage(BaseNetlinkRtMessage):
	+ messages = [
	+ NlRtMsgType.RTM_NEWADDR.value,
	+ NlRtMsgType.RTM_DELADDR.value,
	+ NlRtMsgType.RTM_GETADDR.value,
	+ ]
	+ attr_class_map = ifa_class_map
	+ attr_enum = IfattrType
	+
	+ def __init__(self, helper, nlm_type):
	+ super().__init__(helper, nlm_type)
	+ self.base_hdr = IfaddrMsg()
	+
	+ def parse_base_header(self, data):
	+ if len(data) < sizeof(IfaddrMsg):
	+ raise ValueError("length less than IfaddrMsg header")
	+ rtm_hdr = IfaddrMsg.from_buffer_copy(data)
	+ return (rtm_hdr, sizeof(IfaddrMsg))
	+
	+ def print_base_header(self, hdr, prepend=""):
	+ family = self.helper.get_af_name(hdr.ifa_family)
	+ print("{}family={}, ifa_prefixlen={}, ifa_flags={}, ifa_scope={}, ifa_index={}".format( # noqa: E501
	+ prepend,
	+ family,
	+ hdr.ifa_prefixlen,
	+ hdr.ifa_flags,
	+ hdr.ifa_scope,
	+ hdr.ifa_index))
	+
	+
	+class Nlsock():
	+ def __init__(self, family, helper):
	+ self.helper = helper
	+ self.sock_fd = self._setup_netlink(family)
	+ self._data = bytes()
	+ self.rtm_seq = 1
	+ self.pid = os.getpid()
	+ self.msgmap = self.build_msgmap()
	+ self.set_groups(NlRtGroup.RTNLGRP_IPV4_ROUTE.value \| NlRtGroup.RTNLGRP_IPV6_ROUTE.value) # noqa: E501
	+
	+ def build_msgmap(self):
	+ classes = [NetlinkRtMessage, NetlinkIfaMessage, NetlinkErrorMessage]
	+ xmap = {}
	+ for cls in classes:
	+ for message in cls.messages:
	+ xmap[message] = cls
	+ return xmap
	+
	+ def get_seq(self):
	+ ret = self.rtm_seq
	+ self.rtm_seq += 1
	+ return ret
	+
	+ def _setup_netlink(self, netlink_family) -> int:
	+ family = self.helper.get_af_value("AF_NETLINK")
	+ s = socket.socket(family, socket.SOCK_RAW, netlink_family)
	+ s.setsockopt(270, 10, 1) # NETLINK_CAP_ACK
	+ s.setsockopt(270, 11, 1) # NETLINK_EXT_ACK
	+ return s
	+
	+ def set_groups(self, mask: int):
	+ self.sock_fd.setsockopt(socket.SOL_SOCKET, 1, mask)
	+ # snl = SockaddrNl(nl_len = sizeof(SockaddrNl), nl_family=38,
	+ # nl_pid=self.pid, nl_groups=mask)
	+ # xbuffer = create_string_buffer(sizeof(SockaddrNl))
	+ # memmove(xbuffer, addressof(snl), sizeof(SockaddrNl))
	+ # k = struct.pack("@BBHII", 12, 38, 0, self.pid, mask)
	+ # self.sock_fd.bind(k)
	+
	+ def write_message(self, msg):
	+ print("vvvvvvvv OUT vvvvvvvv")
	+ msg.print_message()
	+ msg_bytes = bytes(msg)
	+ try:
	+ ret = os.write(self.sock_fd.fileno(), bytes(msg))
	+ except Exception as e:
	+ print("write({}) -> {}".format(len(msg_bytes), e))
	+
	+ def parse_message(self, data: bytes):
	+ if len(data) < sizeof(Nlmsghdr):
	+ raise Exception("Short read from nl: {} bytes".format(len(data)))
	+ hdr = Nlmsghdr.from_buffer_copy(data)
	+ nlmsg_type = hdr.nlmsg_type
	+ cls = self.msgmap.get(nlmsg_type)
	+ if not cls:
	+ cls = BaseNetlinkMessage
	+ return cls.from_bytes(self.helper, data)
	+
	+ def write_data(self, data: bytes):
	+ self.sock_fd.send(data)
	+
	+ def read_data(self):
	+ while True:
	+ data = self.sock_fd.recv(65535)
	+ self._data += data
	+ if len(self._data) >= sizeof(Nlmsghdr):
	+ break
	+ if seq is None:
	+ break
	+ hdr = Nlmsghdr.from_buffer_copy(data)
	+ if hdr.nlmsg_pid == self.pid and hdr.nlmsg_seq == seq:
	+ break
	+ return data
	+
	+ def read_message(self) -> bytes:
	+ if len(self._data) < sizeof(Nlmsghdr):
	+ self.read_data()
	+ hdr = Nlmsghdr.from_buffer_copy(self._data)
	+ while (hdr.nlmsg_len > len(self._data)):
	+ self.read_data()
	+ raw_msg = self._data[:hdr.nlmsg_len]
	+ self._data = self._data[hdr.nlmsg_len:]
	+ return self.parse_message(raw_msg)
	+
	+ def fill_msg_seq(self, msg):
	+ msg.nl_hdr.nlmsg_seq = self.get_seq()
	+ msg.nl_hdr.nlmsg_pid = self.pid
	+
	+ def request_ifaces(self):
	+ msg = NetlinkIfaMessage(self.helper, NlRtMsgType.RTM_GETLINK.value)
	+ flags = NlmGetFlags.NLM_F_ROOT.value \| NlmGetFlags.NLM_F_MATCH.value
	+ self.fill_msg_seq(msg)
	+ msg.nl_hdr.nlmsg_flags = flags \| NlmBaseFlags.NLM_F_REQUEST.value
	+
	+ msg_bytes = bytes(msg)
	+ x = self.parse_message(msg_bytes)
	+ x.print_message()
	+ print(msg_bytes)
	+ # Skip family for now
	+ self.write_data(msg_bytes)
	+
	+ def request_ifaddrs(self, family):
	+ msg = NetlinkIfaMessage(self.helper, NlRtMsgType.RTM_GETADDR.value)
	+ flags = NlmGetFlags.NLM_F_ROOT.value \| NlmGetFlags.NLM_F_MATCH.value
	+ self.fill_msg_seq(msg)
	+ msg.base_hdr.ifa_family = family
	+ msg.nl_hdr.nlmsg_flags = flags \| NlmBaseFlags.NLM_F_REQUEST.value
	+
	+ msg_bytes = bytes(msg)
	+ x = self.parse_message(msg_bytes)
	+ x.print_message()
	+ print(msg_bytes)
	+ # Skip family for now
	+ self.write_data(msg_bytes)
	+
	+ def request_routes(self, family):
	+ msg = NetlinkRtMessage(self.helper, NlRtMsgType.RTM_GETROUTE.value)
	+ flags = NlmGetFlags.NLM_F_ROOT.value \| NlmGetFlags.NLM_F_MATCH.value
	+ self.fill_msg_seq(msg)
	+ msg.base_hdr.rtm_family = family
	+ msg.nl_hdr.nlmsg_flags = flags \| NlmBaseFlags.NLM_F_REQUEST.value
	+
	+ msg_bytes = bytes(msg)
	+ x = self.parse_message(msg_bytes)
	+ x.print_message()
	+ print(msg_bytes)
	+ # Skip family for now
	+ self.write_data(msg_bytes)
	+
	+ def request_raw(self):
	+ flags = NlmGetFlags.NLM_F_ROOT.value \| NlmGetFlags.NLM_F_MATCH.value
	+ hdr = Nlmsghdr(
	+ nlmsg_type = NlRtMsgType.RTM_GETROUTE.value,
	+ nlmsg_flags = flags \| NlmBaseFlags.NLM_F_REQUEST.value,
	+ nlmsg_len = sizeof(Nlmsghdr) + sizeof(RtMsgHdr) + 4,
	+ )
	+ rthdr = RtMsgHdr()
	+
	+ rta = RtAttr(rta_len=3, rta_type=RtattrType.RTA_OIF.value)
	+
	+ msg_bytes = bytes(hdr) + bytes(rthdr) + bytes(rta)
	+ # x = self.parse_message(msg_bytes)
	+ # x.print_message()
	+ print(msg_bytes)
	+ self.write_data(msg_bytes)
	+
	+ def request_families(self):
	+ hdr = Nlmsghdr(
	+ nlmsg_type = 16,
	+ nlmsg_flags = NlmBaseFlags.NLM_F_REQUEST.value,
	+ nlmsg_len = sizeof(Nlmsghdr) + sizeof(GenlMsgHdr) + 4,
	+ )
	+ ghdr = GenlMsgHdr(cmd=3)
	+
	+ rta = RtAttr(rta_len=3, rta_type=RtattrType.RTA_OIF)
	+
	+ msg_bytes = bytes(hdr) + bytes(ghdr) + bytes(rta)
	+ x = self.parse_message(msg_bytes)
	+ x.print_message()
	+ print(msg_bytes)
	+ self.write_data(msg_bytes)
	+
	+
	+def main():
	+ helper = NlHelper()
	+ if False:
	+ nl = Nlsock(NlConst.NETLINK_GENERIC, helper)
	+ nl.request_families()
	+ else:
	+ nl = Nlsock(NlConst.NETLINK_ROUTE, helper)
	+ # nl.request_ifaddrs(socket.AF_INET)
	+ # nl.request_raw()
	+ nl.request_routes(0)
	+ # nl.request_ifaces()
	+ while True:
	+ msg = nl.read_message()
	+ print("")
	+ msg.print_message()
	+ msg.print_as_bytes(msg._orig_data, "-- DATA --")
	+
	+ pass
	+
	+
	+if __name__ == "__main__":
	+ main()

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