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[IPV6]: MTU discovery check in ip6_fragment()

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Adds a check in ip6_fragment() mirroring ip_fragment() for packets
that we can't fragment, and sends an ICMP Packet Too Big message
in response.

Signed-off-by: John Heffner <jheffner@psc.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
John Heffner 2007-04-20 15:52:39 -07:00 committed by David S. Miller
parent fd44de7cc1
commit b881ef7603
1 changed files with 13 additions and 0 deletions
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13
net/ipv6/ip6_output.c
View file

@ -567,6 +567,19 @@ static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
nexthdr = *prevhdr;
mtu = dst_mtu(&rt->u.dst);
/* We must not fragment if the socket is set to force MTU discovery
* or if the skb it not generated by a local socket. (This last
* check should be redundant, but it's free.)
*/
if (!np || np->pmtudisc >= IPV6_PMTUDISC_DO) {
skb->dev = skb->dst->dev;
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, skb->dev);
IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS);
kfree_skb(skb);
return -EMSGSIZE;
}
if (np && np->frag_size < mtu) {
if (np->frag_size)
mtu = np->frag_size;