Sit uses skb->protocol to determine packet type, and bails out if it's not set. For AF_PACKET injection, we need to support its call chain of:
packet_sendmsg -> packet_snd -> packet_parse_headers -> dev_parse_header_protocol -> parse_protocol Without a valid parse_protocol, this returns zero, and sit rejects the skb. So, this wires up the ip_tunnel handler for layer 3 packets for that case. Reported-by: Willem de Bruijn <willemdebruijn.ker...@gmail.com> Signed-off-by: Jason A. Donenfeld <ja...@zx2c4.com> --- net/ipv6/sit.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c index 1fbb4dfbb191..5e2c34c0ac97 100644 --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -1421,6 +1421,7 @@ static void ipip6_tunnel_setup(struct net_device *dev) int t_hlen = tunnel->hlen + sizeof(struct iphdr); dev->netdev_ops = &ipip6_netdev_ops; + dev->header_ops = &ip_tunnel_header_ops; dev->needs_free_netdev = true; dev->priv_destructor = ipip6_dev_free; -- 2.27.0