The purpose of commit 703eec1b2422 ("virtio_net: fixing XDP for fully checksummed packets handling") is to record the flags in advance, as their value may be overwritten in the XDP case. However, the flags recorded under big mode are incorrect, because in big mode, the passed buf does not point to the rx buffer, but rather to the page of the submitted buffer. This commit fixes this issue. For the small mode, the commit c11a49d58ad2 ("virtio_net: Fix mismatched buf address when unmapping for small packets") fixed it. Fixes: 703eec1b2422 ("virtio_net: fixing XDP for fully checksummed packets handling") Signed-off-by: Xuan Zhuo Acked-by: Jason Wang --- drivers/net/virtio_net.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 8e8a179aaa49..59f116b609f6 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -2625,22 +2625,28 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq, return; } - /* 1. Save the flags early, as the XDP program might overwrite them. + /* About the flags below: + * 1. Save the flags early, as the XDP program might overwrite them. * These flags ensure packets marked as VIRTIO_NET_HDR_F_DATA_VALID * stay valid after XDP processing. * 2. XDP doesn't work with partially checksummed packets (refer to * virtnet_xdp_set()), so packets marked as * VIRTIO_NET_HDR_F_NEEDS_CSUM get dropped during XDP processing. */ - flags = ((struct virtio_net_common_hdr *)buf)->hdr.flags; - if (vi->mergeable_rx_bufs) + if (vi->mergeable_rx_bufs) { + flags = ((struct virtio_net_common_hdr *)buf)->hdr.flags; skb = receive_mergeable(dev, vi, rq, buf, ctx, len, xdp_xmit, stats); - else if (vi->big_packets) + } else if (vi->big_packets) { + void *p = page_address((struct page *)buf); + + flags = ((struct virtio_net_common_hdr *)p)->hdr.flags; skb = receive_big(dev, vi, rq, buf, len, stats); - else + } else { + flags = ((struct virtio_net_common_hdr *)buf)->hdr.flags; skb = receive_small(dev, vi, rq, buf, ctx, len, xdp_xmit, stats); + } if (unlikely(!skb)) return; -- 2.32.0.3.g01195cf9f Although `virtio_net_hdr_from_skb` is used in several places outside of `virtio-net.c`, the `hdr_len` field is only utilized by the device according to the specification. Therefore, we do not need to set `hdr_len` unless the header is actually passed to the device. Signed-off-by: Xuan Zhuo --- include/linux/virtio_net.h | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index 4d1780848d0e..710ae0d2d336 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -218,9 +218,14 @@ 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); - /* This is a hint as to how much should be linear. */ - hdr->hdr_len = __cpu_to_virtio16(little_endian, - skb_headlen(skb)); + /* In certain code paths (such as the af_packet.c receive path), + * this function may be called without a transport header. + * In this case, we do not need to set the hdr_len. + */ + if (skb_transport_header_was_set(skb)) + 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) -- 2.32.0.3.g01195cf9f 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 | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index 710ae0d2d336..6ef0b737d548 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -217,25 +217,35 @@ 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 = 0; /* In certain code paths (such as the af_packet.c receive path), * this function may be called without a transport header. * In this case, we do not need to set the hdr_len. */ if (skb_transport_header_was_set(skb)) - hdr->hdr_len = __cpu_to_virtio16(little_endian, - skb_headlen(skb)); + hdr_len = skb_transport_offset(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) + if (hdr_len) + 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) + if (hdr_len) + hdr_len += tcp_hdrlen(skb); + } else if (sinfo->gso_type & SKB_GSO_UDP_L4) { hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP_L4; - else + if (hdr_len) + hdr_len += sizeof(struct udphdr); + } else { return -EINVAL; + } + + hdr->hdr_len = __cpu_to_virtio16(little_endian, hdr_len); + if (sinfo->gso_type & SKB_GSO_TCP_ECN) hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN; } else -- 2.32.0.3.g01195cf9f The commit a2fb4bc4e2a6a03 ("net: implement virtio helpers to handle UDP GSO tunneling.") introduces support for the UDP GSO tunnel feature in virtio-net. The virtio spec says: If the \field{gso_type} has the VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV4 bit or VIRTIO_NET_HDR_GSO_UDP_TUNNEL_IPV6 bit set, \field{hdr_len} accounts for all the headers up to and including the inner transport. The commit did not update the hdr_len to include the inner transport. I observed that the "hdr_len" is 116 for this packet: 17:36:18.241105 52:55:00:d1:27:0a > 2e:2c:df:46:a9:e1, ethertype IPv4 (0x0800), length 2912: (tos 0x0, ttl 64, id 45197, offset 0, flags [none], proto UDP (17), length 2898) 192.168.122.100.50613 > 192.168.122.1.4789: [bad udp cksum 0x8106 -> 0x26a0!] VXLAN, flags [I] (0x08), vni 1 fa:c3:ba:82:05:ee > ce:85:0c:31:77:e5, ethertype IPv4 (0x0800), length 2862: (tos 0x0, ttl 64, id 14678, offset 0, flags [DF], proto TCP (6), length 2848) 192.168.3.1.49880 > 192.168.3.2.9898: Flags [P.], cksum 0x9266 (incorrect -> 0xaa20), seq 515667:518463, ack 1, win 64, options [nop,nop,TS val 2990048824 ecr 2798801412], length 2796 116 = 14(mac) + 20(ip) + 8(udp) + 8(vxlan) + 14(inner mac) + 20(inner ip) + 32(innner tcp) Fixes: a2fb4bc4e2a6a03 ("net: implement virtio helpers to handle UDP GSO tunneling.") Signed-off-by: Xuan Zhuo --- include/linux/virtio_net.h | 35 ++++++++++++++++++++++++----------- 1 file changed, 24 insertions(+), 11 deletions(-) diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h index 6ef0b737d548..46b04816d333 100644 --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -207,6 +207,14 @@ 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_tcp_hdrlen(const struct sk_buff *skb, bool tnl) +{ + if (tnl) + return inner_tcp_hdrlen(skb); + + return tcp_hdrlen(skb); +} + static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb, struct virtio_net_hdr *hdr, bool little_endian, @@ -217,25 +225,33 @@ 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); + bool tnl = false; u16 hdr_len = 0; - /* In certain code paths (such as the af_packet.c receive path), - * this function may be called without a transport header. - * In this case, we do not need to set the hdr_len. - */ - if (skb_transport_header_was_set(skb)) - hdr_len = skb_transport_offset(skb); + if (sinfo->gso_type & (SKB_GSO_UDP_TUNNEL | + SKB_GSO_UDP_TUNNEL_CSUM)) { + tnl = true; + hdr_len = skb_inner_transport_offset(skb); + + } else { + /* In certain code paths (such as the af_packet.c receive path), + * this function may be called without a transport header. + * In this case, we do not need to set the hdr_len. + */ + if (skb_transport_header_was_set(skb)) + hdr_len = skb_transport_offset(skb); + } hdr->gso_size = __cpu_to_virtio16(little_endian, sinfo->gso_size); if (sinfo->gso_type & SKB_GSO_TCPV4) { hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; if (hdr_len) - hdr_len += tcp_hdrlen(skb); + hdr_len += virtio_net_tcp_hdrlen(skb, tnl); } else if (sinfo->gso_type & SKB_GSO_TCPV6) { hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; if (hdr_len) - hdr_len += tcp_hdrlen(skb); + hdr_len += virtio_net_tcp_hdrlen(skb, tnl); } else if (sinfo->gso_type & SKB_GSO_UDP_L4) { hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP_L4; if (hdr_len) @@ -420,10 +436,7 @@ virtio_net_hdr_tnl_from_skb(const struct sk_buff *skb, vhdr->hash_hdr.hash_report = 0; vhdr->hash_hdr.padding = 0; - /* Let the basic parsing deal with plain GSO features. */ - skb_shinfo(skb)->gso_type &= ~tnl_gso_type; ret = virtio_net_hdr_from_skb(skb, hdr, true, false, vlan_hlen); - skb_shinfo(skb)->gso_type |= tnl_gso_type; if (ret) return ret; -- 2.32.0.3.g01195cf9f