* [PATCH] net: ipv6: send pkttoobig immediately if orig frag size > mtu
@ 2014-05-04 22:03 Florian Westphal
2014-05-07 19:28 ` David Miller
0 siblings, 1 reply; 2+ messages in thread
From: Florian Westphal @ 2014-05-04 22:03 UTC (permalink / raw)
To: netdev; +Cc: Florian Westphal
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 <fw@strlen.de>
---
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 40e7581..31a38bd 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;
--
1.8.1.5
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] net: ipv6: send pkttoobig immediately if orig frag size > mtu
2014-05-04 22:03 [PATCH] net: ipv6: send pkttoobig immediately if orig frag size > mtu Florian Westphal
@ 2014-05-07 19:28 ` David Miller
0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2014-05-07 19:28 UTC (permalink / raw)
To: fw; +Cc: netdev
From: Florian Westphal <fw@strlen.de>
Date: Mon, 5 May 2014 00:03:34 +0200
> 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 <fw@strlen.de>
Also applied and queued up for -stable, thanks Florian.
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