Change Details

If using the virtio network channel, transferring packets between a host and a VM requires translating the packet's meta information between the fields in the virtio network header and, in the case of FreeBSD, the fields in the mbuf. On the VM side, this is done by the vtnet interface driver. On the host side, this is often done by the tap interface driver. Both the vtnet driver and the tap driver, do the translation very similarly and in two ways less than good: 1. When sending a packet over the virtio network channel, they do not translate the `CSUM_DATA_VALID | CSUM_PSEUDO_HDR` mbuf flags in `VIRTIO_NET_HDR_F_DATA_VALID`. 2. When receiving a packet over the virtio network channel, they translate `VIRTIO_NET_HDR_F_NEEDS_CSUM` in the `CSUM_DATA_VALID | CSUM_PSEUDO_HDR` mbuf flags. This patch adds for both drivers the translation 1. and changes the translation 2. of `VIRTIO_NET_HDR_F_NEEDS_CSUM` in the mbuf transmission checksum offload flag (`CSUM_TCP`, `CSUM_TCP_IPV6`, `CSUM_UDP`, or `CSUM_UDP_IPV6`). Note that D51475 added the handling of an incoming packet with a transmission checksum offload flag set.

If using the virtio network channel, transferring packets between a host and a VM requires translating the packet's meta information between the fields in the virtio network header and, in the case of FreeBSD, the fields in the mbuf. On the VM side, this is done by the vtnet interface driver. The vtnet driver does the translation in two ways less than good: 1. When sending a packet over the virtio network channel, it does not translate the `CSUM_DATA_VALID | CSUM_PSEUDO_HDR` mbuf flags in `VIRTIO_NET_HDR_F_DATA_VALID`. 2. When receiving a packet over the virtio network channel, it translates `VIRTIO_NET_HDR_F_NEEDS_CSUM` in the `CSUM_DATA_VALID | CSUM_PSEUDO_HDR` mbuf flags. This patch adds for the vtnet driver the translation 1. and changes the translation 2. of `VIRTIO_NET_HDR_F_NEEDS_CSUM` in the mbuf transmission checksum offload flag (`CSUM_TCP`, `CSUM_TCP_IPV6`, `CSUM_UDP`, or `CSUM_UDP_IPV6`). Note that D51475 added the handling of an incoming packet with a transmission checksum offload flag set.

If using the virtio network channel, transferring packets between a host and a VM requires translating the packet's meta information between the fields in the virtio network header and, in the case of FreeBSD, the fields in the mbuf. On the VM side, this is done by the vtnet interface driver. On the host side, this is often done by the tap interface driver.The vtnet driver does the translation in two ways less than good: Both the vtnet driver and1. When sending a packet over the tap drivervirtio network channel, do theit does not translation very similarly ande the `CSUM_DATA_VALID | CSUM_PSEUDO_HDR` mbuf flags in two ways less than good:`VIRTIO_NET_HDR_F_DATA_VALID`. 12. When sendingreceiving a packet over the virtio network channel, they do not translateit translates `VIRTIO_NET_HDR_F_NEEDS_CSUM` in the `CSUM_DATA_VALID | CSUM_PSEUDO_HDR` mbuf flags in `VIRTIO_NET_HDR_F_DATA_VALID`. 2. When receiving a packet over the virtio network channel, they translate `VIRTIO_NET_HDR_F_NEEDS_CSUM` in the `CSUM_DATA_VALID | CSUM_PSEUDO_HDR` mbuf flags. This patch adds for boththe vtnet drivers the translation 1. and changes the translation 2. of `VIRTIO_NET_HDR_F_NEEDS_CSUM` in the mbuf transmission checksum offload flag (`CSUM_TCP`, `CSUM_TCP_IPV6`, `CSUM_UDP`, or `CSUM_UDP_IPV6`). Note that D51475 added the handling of an incoming packet with a transmission checksum offload flag set.