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Commit b881ef76 authored by John Heffner's avatar John Heffner Committed by David S. Miller
Browse files

[IPV6]: MTU discovery check in ip6_fragment() 



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: default avatarJohn Heffner <jheffner@psc.edu>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent fd44de7c

net/ipv6/ip6_output.c

+13 −0
Original line number Diff line number Diff line
@@ -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;