The commit be50da3e9d4a ("net: virtio_net: implement exact header length guest feature") introduces support for the VIRTIO_NET_F_GUEST_HDRLEN feature in virtio-net. This feature requires virtio-net to set hdr_len to the actual header length of the packet when transmitting, the number of bytes from the start of the packet to the beginning of the transport-layer payload. However, in practice, hdr_len was being set using skb_headlen(skb), which is clearly incorrect. This commit fixes that issue. Fixes: be50da3e9d4a ("net: virtio_net: implement exact header length guest feature") Signed-off-by: Xuan Zhuo --- include/linux/virtio_net.h | 28 +++++++++++++++++++++------- 1 file changed, 21 insertions(+), 7 deletions(-) diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index 20e0584db1dd..10ca53b3a399 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -217,20 +217,34 @@ static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, if (skb_is_gso(skb)) { struct skb_shared_info *sinfo = skb_shinfo(skb); + u16 hdr_len; - /* This is a hint as to how much should be linear. */ - hdr->hdr_len = __cpu_to_virtio16(little_endian, - skb_headlen(skb)); hdr->gso_size = __cpu_to_virtio16(little_endian, sinfo->gso_size); - if (sinfo->gso_type & SKB_GSO_TCPV4) + if (sinfo->gso_type & SKB_GSO_TCPV4) { hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; - else if (sinfo->gso_type & SKB_GSO_TCPV6) + hdr_len = tcp_hdrlen(skb); + } else if (sinfo->gso_type & SKB_GSO_TCPV6) { hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; - else if (sinfo->gso_type & SKB_GSO_UDP_L4) + hdr_len = tcp_hdrlen(skb); + } else if (sinfo->gso_type & SKB_GSO_UDP_L4) { hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP_L4; - else + hdr_len = sizeof(struct udphdr); + } else { return -EINVAL; + } + + /* In certain code paths (such as the TUN receive path), this + * function may be called without a transport header. + */ + if (skb_transport_header_was_set(skb)) { + hdr_len += skb_transport_offset(skb); + hdr->hdr_len = __cpu_to_virtio16(little_endian, + hdr_len); + } else { + hdr->hdr_len = 0; + } + if (sinfo->gso_type & SKB_GSO_TCP_ECN) hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN; } else -- 2.32.0.3.g01195cf9f