From 7a7ffbabf99445704be01bff5d7e360da908cf8e Mon Sep 17 00:00:00 2001 From: Wei-Chun Chao Date: Thu, 26 Dec 2013 13:10:22 -0800 Subject: [PATCH] ipv4: fix tunneled VM traffic over hw VXLAN/GRE GSO NIC VM to VM GSO traffic is broken if it goes through VXLAN or GRE tunnel and the physical NIC on the host supports hardware VXLAN/GRE GSO offload (e.g. bnx2x and next-gen mlx4). Two issues - (VXLAN) VM traffic has SKB_GSO_DODGY and SKB_GSO_UDP_TUNNEL with SKB_GSO_TCP/UDP set depending on the inner protocol. GSO header integrity check fails in udp4_ufo_fragment if inner protocol is TCP. Also gso_segs is calculated incorrectly using skb->len that includes tunnel header. Fix: robust check should only be applied to the inner packet. (VXLAN & GRE) Once GSO header integrity check passes, NULL segs is returned and the original skb is sent to hardware. However the tunnel header is already pulled. Fix: tunnel header needs to be restored so that hardware can perform GSO properly on the original packet. Signed-off-by: Wei-Chun Chao Signed-off-by: David S. Miller --- include/linux/netdevice.h | 13 +++++++++++++ net/ipv4/gre_offload.c | 11 +++++++---- net/ipv4/udp.c | 6 +++++- net/ipv4/udp_offload.c | 37 +++++++++++++++++++------------------ 4 files changed, 44 insertions(+), 23 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 7514b9c..5faaadb 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3017,6 +3017,19 @@ static inline void netif_set_gso_max_size(struct net_device *dev, dev->gso_max_size = size; } +static inline void skb_gso_error_unwind(struct sk_buff *skb, __be16 protocol, + int pulled_hlen, u16 mac_offset, + int mac_len) +{ + skb->protocol = protocol; + skb->encapsulation = 1; + skb_push(skb, pulled_hlen); + skb_reset_transport_header(skb); + skb->mac_header = mac_offset; + skb->network_header = skb->mac_header + mac_len; + skb->mac_len = mac_len; +} + static inline bool netif_is_macvlan(struct net_device *dev) { return dev->priv_flags & IFF_MACVLAN; diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c index e5d4361..2cd02f3 100644 --- a/net/ipv4/gre_offload.c +++ b/net/ipv4/gre_offload.c @@ -28,6 +28,7 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb, netdev_features_t enc_features; int ghl = GRE_HEADER_SECTION; struct gre_base_hdr *greh; + u16 mac_offset = skb->mac_header; int mac_len = skb->mac_len; __be16 protocol = skb->protocol; int tnl_hlen; @@ -58,13 +59,13 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb, } else csum = false; + if (unlikely(!pskb_may_pull(skb, ghl))) + goto out; + /* setup inner skb. */ skb->protocol = greh->protocol; skb->encapsulation = 0; - if (unlikely(!pskb_may_pull(skb, ghl))) - goto out; - __skb_pull(skb, ghl); skb_reset_mac_header(skb); skb_set_network_header(skb, skb_inner_network_offset(skb)); @@ -73,8 +74,10 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb, /* segment inner packet. */ enc_features = skb->dev->hw_enc_features & netif_skb_features(skb); segs = skb_mac_gso_segment(skb, enc_features); - if (!segs || IS_ERR(segs)) + if (!segs || IS_ERR(segs)) { + skb_gso_error_unwind(skb, protocol, ghl, mac_offset, mac_len); goto out; + } skb = segs; tnl_hlen = skb_tnl_header_len(skb); diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index f140048..a7e4729 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -2478,6 +2478,7 @@ struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, netdev_features_t features) { struct sk_buff *segs = ERR_PTR(-EINVAL); + u16 mac_offset = skb->mac_header; int mac_len = skb->mac_len; int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb); __be16 protocol = skb->protocol; @@ -2497,8 +2498,11 @@ struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb, /* segment inner packet. */ enc_features = skb->dev->hw_enc_features & netif_skb_features(skb); segs = skb_mac_gso_segment(skb, enc_features); - if (!segs || IS_ERR(segs)) + if (!segs || IS_ERR(segs)) { + skb_gso_error_unwind(skb, protocol, tnl_hlen, mac_offset, + mac_len); goto out; + } outer_hlen = skb_tnl_header_len(skb); skb = segs; diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c index 83206de..79c62bd 100644 --- a/net/ipv4/udp_offload.c +++ b/net/ipv4/udp_offload.c @@ -41,6 +41,14 @@ static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, { struct sk_buff *segs = ERR_PTR(-EINVAL); unsigned int mss; + int offset; + __wsum csum; + + if (skb->encapsulation && + skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL) { + segs = skb_udp_tunnel_segment(skb, features); + goto out; + } mss = skb_shinfo(skb)->gso_size; if (unlikely(skb->len <= mss)) @@ -63,27 +71,20 @@ static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, goto out; } + /* Do software UFO. Complete and fill in the UDP checksum as + * HW cannot do checksum of UDP packets sent as multiple + * IP fragments. + */ + offset = skb_checksum_start_offset(skb); + csum = skb_checksum(skb, offset, skb->len - offset, 0); + offset += skb->csum_offset; + *(__sum16 *)(skb->data + offset) = csum_fold(csum); + skb->ip_summed = CHECKSUM_NONE; + /* Fragment the skb. IP headers of the fragments are updated in * inet_gso_segment() */ - if (skb->encapsulation && skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL) - segs = skb_udp_tunnel_segment(skb, features); - else { - int offset; - __wsum csum; - - /* Do software UFO. Complete and fill in the UDP checksum as - * HW cannot do checksum of UDP packets sent as multiple - * IP fragments. - */ - offset = skb_checksum_start_offset(skb); - csum = skb_checksum(skb, offset, skb->len - offset, 0); - offset += skb->csum_offset; - *(__sum16 *)(skb->data + offset) = csum_fold(csum); - skb->ip_summed = CHECKSUM_NONE; - - segs = skb_segment(skb, features); - } + segs = skb_segment(skb, features); out: return segs; } -- 2.7.4