net/af_packet: add VLAN support for AF_PACKET SOCK_RAW GSO
Currently, the kernel drops GSO VLAN tagged packet if it's created with socket(AF_PACKET, SOCK_RAW, 0) plus virtio_net_hdr. The reason is AF_PACKET doesn't adjust the skb network header if there is a VLAN tag. Then after virtio_net_hdr_set_proto() called, the skb->protocol will be set to ETH_P_IP/IPv6. And in later inet/ipv6_gso_segment() the skb is dropped as network header position is invalid. Let's handle VLAN packets by adjusting network header position in packet_parse_headers(). The adjustment is safe and does not affect the later xmit as tap device also did that. In packet_snd(), packet_parse_headers() need to be moved before calling virtio_net_hdr_set_proto(), so we can set correct skb->protocol and network header first. There is no need to update tpacket_snd() as it calls packet_parse_headers() in tpacket_fill_skb(), which is already before calling virtio_net_hdr_* functions. skb->no_fcs setting is also moved upper to make all skb settings together and keep consistency with function packet_sendmsg_spkt(). Signed-off-by: Hangbin Liu <liuhangbin@gmail.com> Acked-by: Willem de Bruijn <willemb@google.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Link: https://lore.kernel.org/r/20220425014502.985464-1-liuhangbin@gmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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