From: Florian Westphal Date: Sun, 4 May 2014 22:03:34 +0000 (+0200) Subject: net: ipv6: send pkttoobig immediately if orig frag size > mtu X-Git-Url: http://git.mmlx.us/?a=commitdiff_plain;h=bbdd224c0ad28a77161aeb8c45d34fe0928ef997;p=linux-edison.git net: ipv6: send pkttoobig immediately if orig frag size > mtu [ Upstream commit 418a31561d594a2b636c1e2fa94ecd9e1245abb1 ] If conntrack defragments incoming ipv6 frags it stores largest original frag size in ip6cb and sets ->local_df. We must thus first test the largest original frag size vs. mtu, and not vice versa. Without this patch PKTTOOBIG is still generated in ip6_fragment() later in the stack, but 1) IPSTATS_MIB_INTOOBIGERRORS won't increment 2) packet did (needlessly) traverse netfilter postrouting hook. Fixes: fe6cc55f3a9 ("net: ip, ipv6: handle gso skbs in forwarding path") Signed-off-by: Florian Westphal Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 32fb114b86b..ffa8d295c56 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -347,12 +347,16 @@ static inline int ip6_forward_finish(struct sk_buff *skb) static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu) { - if (skb->len <= mtu || skb->local_df) + if (skb->len <= mtu) return false; + /* ipv6 conntrack defrag sets max_frag_size + local_df */ if (IP6CB(skb)->frag_max_size && IP6CB(skb)->frag_max_size > mtu) return true; + if (skb->local_df) + return false; + if (skb_is_gso(skb) && skb_gso_network_seglen(skb) <= mtu) return false;