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 --- drivers/net/tun_vnet.h | 2 +- drivers/net/virtio_net.c | 6 +++- include/linux/virtio_net.h | 58 ++++++++++++++++++++++++++++++-------- 3 files changed, 53 insertions(+), 13 deletions(-) diff --git a/drivers/net/tun_vnet.h b/drivers/net/tun_vnet.h index a5f93b6c4482..fa5cab9d3e55 100644 --- a/drivers/net/tun_vnet.h +++ b/drivers/net/tun_vnet.h @@ -244,7 +244,7 @@ tun_vnet_hdr_tnl_from_skb(unsigned int flags, if (virtio_net_hdr_tnl_from_skb(skb, tnl_hdr, has_tnl_offload, tun_vnet_is_little_endian(flags), - vlan_hlen, true)) { + vlan_hlen, true, false)) { struct virtio_net_hdr_v1 *hdr = &tnl_hdr->hash_hdr.hdr; struct skb_shared_info *sinfo = skb_shinfo(skb); diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 72d6a9c6a5a2..7106333ef904 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -3267,8 +3267,12 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb, bool orphan) struct virtio_net_hdr_v1_hash_tunnel *hdr; int num_sg; unsigned hdr_len = vi->hdr_len; + bool feature_hdrlen; bool can_push; + feature_hdrlen = virtio_has_feature(vi->vdev, + VIRTIO_NET_F_GUEST_HDRLEN); + pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest); /* Make sure it's safe to cast between formats */ @@ -3288,7 +3292,7 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb, bool orphan) if (virtio_net_hdr_tnl_from_skb(skb, hdr, vi->tx_tnl, virtio_is_little_endian(vi->vdev), 0, - false)) + false, feature_hdrlen)) return -EPROTO; if (vi->mergeable_rx_bufs) diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index 75dabb763c65..23f42bb8ece0 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -207,20 +207,40 @@ static inline int virtio_net_hdr_to_skb(struct sk_buff *skb, return __virtio_net_hdr_to_skb(skb, hdr, little_endian, hdr->gso_type); } -static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, - struct virtio_net_hdr *hdr, - bool little_endian, - bool has_data_valid, - int vlan_hlen) +static inline void virtio_net_set_hdrlen(const struct sk_buff *skb, + struct virtio_net_hdr *hdr, + bool little_endian, + bool feature_hdrlen) +{ + u16 hdr_len; + + if (feature_hdrlen) { + hdr_len = skb_transport_offset(skb); + + if (hdr->gso_type == VIRTIO_NET_HDR_GSO_UDP_L4) + hdr_len += sizeof(struct udphdr); + else + hdr_len += tcp_hdrlen(skb); + } else { + /* This is a hint as to how much should be linear. */ + hdr_len = skb_headlen(skb); + } + + hdr->hdr_len = __cpu_to_virtio16(little_endian, hdr_len); +} + +static inline int __virtio_net_hdr_from_skb(const struct sk_buff *skb, + struct virtio_net_hdr *hdr, + bool little_endian, + bool has_data_valid, + bool feature_hdrlen, + int vlan_hlen) { memset(hdr, 0, sizeof(*hdr)); /* no info leak */ if (skb_is_gso(skb)) { struct skb_shared_info *sinfo = skb_shinfo(skb); - /* 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) @@ -231,6 +251,10 @@ static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP_L4; else return -EINVAL; + + virtio_net_set_hdrlen(skb, hdr, little_endian, + feature_hdrlen); + if (sinfo->gso_type & SKB_GSO_TCP_ECN) hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN; } else @@ -250,6 +274,16 @@ static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, return 0; } +static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, + struct virtio_net_hdr *hdr, + bool little_endian, + bool has_data_valid, + int vlan_hlen) +{ + return __virtio_net_hdr_from_skb(skb, hdr, little_endian, + has_data_valid, false, vlan_hlen); +} + static inline unsigned int virtio_l3min(bool is_ipv6) { return is_ipv6 ? sizeof(struct ipv6hdr) : sizeof(struct iphdr); @@ -385,7 +419,8 @@ virtio_net_hdr_tnl_from_skb(const struct sk_buff *skb, bool tnl_hdr_negotiated, bool little_endian, int vlan_hlen, - bool has_data_valid) + bool has_data_valid, + bool feature_hdrlen) { struct virtio_net_hdr *hdr = (struct virtio_net_hdr *)vhdr; unsigned int inner_nh, outer_th; @@ -395,8 +430,9 @@ virtio_net_hdr_tnl_from_skb(const struct sk_buff *skb, tnl_gso_type = skb_shinfo(skb)->gso_type & (SKB_GSO_UDP_TUNNEL | SKB_GSO_UDP_TUNNEL_CSUM); if (!tnl_gso_type) - return virtio_net_hdr_from_skb(skb, hdr, little_endian, - has_data_valid, vlan_hlen); + return __virtio_net_hdr_from_skb(skb, hdr, little_endian, + has_data_valid, + feature_hdrlen, vlan_hlen); /* Tunnel support not negotiated but skb ask for it. */ if (!tnl_hdr_negotiated) -- 2.32.0.3.g01195cf9f