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| author | Patrick McHardy <kaber@trash.net> | 2012-08-26 19:13:55 +0200 |
|---|---|---|
| committer | Patrick McHardy <kaber@trash.net> | 2012-08-26 19:13:55 +0200 |
| commit | 5f2d04f1f9b52604fca6ee08a77972c0df67e082 (patch) | |
| tree | f4caa0aa602f6044f1fc20c6dfa89527183803d1 /include/net/ip.h | |
| parent | 0fa7fa98dbcc2789409ed24e885485e645803d7f (diff) | |
| download | lwn-5f2d04f1f9b52604fca6ee08a77972c0df67e082.tar.gz lwn-5f2d04f1f9b52604fca6ee08a77972c0df67e082.zip | |
ipv4: fix path MTU discovery with connection tracking
IPv4 conntrack defragments incoming packet at the PRE_ROUTING hook and
(in case of forwarded packets) refragments them at POST_ROUTING
independent of the IP_DF flag. Refragmentation uses the dst_mtu() of
the local route without caring about the original fragment sizes,
thereby breaking PMTUD.
This patch fixes this by keeping track of the largest received fragment
with IP_DF set and generates an ICMP fragmentation required error during
refragmentation if that size exceeds the MTU.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Acked-by: Eric Dumazet <edumazet@google.com>
Acked-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/ip.h')
| -rw-r--r-- | include/net/ip.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/net/ip.h b/include/net/ip.h index 5a5d84d3d2c6..0707fb9551aa 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -42,6 +42,8 @@ struct inet_skb_parm { #define IPSKB_XFRM_TRANSFORMED 4 #define IPSKB_FRAG_COMPLETE 8 #define IPSKB_REROUTED 16 + + u16 frag_max_size; }; static inline unsigned int ip_hdrlen(const struct sk_buff *skb) |