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authorPatrick McHardy <kaber@trash.net>2012-08-26 19:13:55 +0200
committerPatrick McHardy <kaber@trash.net>2012-08-26 19:13:55 +0200
commit5f2d04f1f9b52604fca6ee08a77972c0df67e082 (patch)
treef4caa0aa602f6044f1fc20c6dfa89527183803d1 /include/net/ip.h
parent0fa7fa98dbcc2789409ed24e885485e645803d7f (diff)
downloadlinux-5f2d04f1f9b52604fca6ee08a77972c0df67e082.tar.bz2
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.h2
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)