From 418a31561d594a2b636c1e2fa94ecd9e1245abb1 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Mon, 5 May 2014 00:03:34 +0200 Subject: [PATCH] net: ipv6: send pkttoobig immediately if orig frag size > mtu 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 --- net/ipv6/ip6_output.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 40e7581374f7..31a38bde69ef 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -344,12 +344,16 @@ static unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst) 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; -- 2.20.1