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| author | Shmulik Ladkani <shmulik.ladkani@gmail.com> | 2016-06-29 20:47:03 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-06-30 15:02:48 +0200 |
| commit | fedbb6b4ff341c1e2120f4ffbf367fd78ac3e8f3 (patch) | |
| tree | aec9b6ddce0a103d82704f52a693f1d3cd238dbb | |
| parent | Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/jkirsh... (diff) | |
| download | linux-fedbb6b4ff341c1e2120f4ffbf367fd78ac3e8f3.tar.xz linux-fedbb6b4ff341c1e2120f4ffbf367fd78ac3e8f3.zip | |
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 <shmulik.ladkani@gmail.com>
Reviewed-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/net/ip.h | 5 | ||||
| -rw-r--r-- | net/bridge/br_netfilter_hooks.c | 2 | ||||
| -rw-r--r-- | net/ipv4/ip_output.c | 4 |
3 files changed, 5 insertions, 6 deletions
diff --git a/include/net/ip.h b/include/net/ip.h index 37165fba3741..08f36cd2b874 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -313,10 +313,9 @@ static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst, return min(dst->dev->mtu, IP_MAX_MTU); } -static inline unsigned int ip_skb_dst_mtu(const struct sk_buff *skb) +static inline unsigned int ip_skb_dst_mtu(struct sock *sk, + const struct sk_buff *skb) { - struct sock *sk = skb->sk; - if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) { bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED; 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); } #endif - 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; |