path: root/net
diff options
authorShmulik Ladkani <>2016-06-29 21:47:03 +0300
committerDavid S. Miller <>2016-06-30 09:02:48 -0400
commitfedbb6b4ff341c1e2120f4ffbf367fd78ac3e8f3 (patch)
treeaec9b6ddce0a103d82704f52a693f1d3cd238dbb /net
parent5ab0d6a016b19d8cbd503eafd0ef701cfd854402 (diff)
ipv4: Fix ip_skb_dst_mtu to use the sk passed by ip_finish_output
ip_skb_dst_mtu uses skb->sk, assuming it is an AF_INET socket (e.g. it calls ip_sk_use_pmtu which casts sk as an inet_sk). However, in the case of UDP tunneling, the skb->sk is not necessarily an inet socket (could be AF_PACKET socket, or AF_UNSPEC if arriving from tun/tap). OTOH, the sk passed as an argument throughout IP stack's output path is the one which is of PMTU interest: - In case of local sockets, sk is same as skb->sk; - In case of a udp tunnel, sk is the tunneling socket. Fix, by passing ip_finish_output's sk to ip_skb_dst_mtu. This augments 7026b1ddb6 'netfilter: Pass socket pointer down through okfn().' Signed-off-by: Shmulik Ladkani <> Reviewed-by: Hannes Frederic Sowa <> Signed-off-by: David S. Miller <>
Diffstat (limited to 'net')
2 files changed, 3 insertions, 3 deletions
diff --git a/net/bridge/br_netfilter_hooks.c b/net/bridge/br_netfilter_hooks.c
index 2d25979273a6..77e7f69bf80d 100644
--- a/net/bridge/br_netfilter_hooks.c
+++ b/net/bridge/br_netfilter_hooks.c
@@ -700,7 +700,7 @@ static int
br_nf_ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
int (*output)(struct net *, struct sock *, struct sk_buff *))
- unsigned int mtu = ip_skb_dst_mtu(skb);
+ unsigned int mtu = ip_skb_dst_mtu(sk, skb);
struct iphdr *iph = ip_hdr(skb);
if (unlikely(((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) ||
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 124bf0a66328..4bd4921639c3 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -271,7 +271,7 @@ static int ip_finish_output(struct net *net, struct sock *sk, struct sk_buff *sk
return dst_output(net, sk, skb);
- mtu = ip_skb_dst_mtu(skb);
+ mtu = ip_skb_dst_mtu(sk, skb);
if (skb_is_gso(skb))
return ip_finish_output_gso(net, sk, skb, mtu);
@@ -541,7 +541,7 @@ int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
iph = ip_hdr(skb);
- mtu = ip_skb_dst_mtu(skb);
+ mtu = ip_skb_dst_mtu(sk, skb);
if (IPCB(skb)->frag_max_size && IPCB(skb)->frag_max_size < mtu)
mtu = IPCB(skb)->frag_max_size;