summary refs log tree commit diff
path: root/net/ipv6
diff options
context:
space:
mode:
authorJohn Heffner <jheffner@psc.edu>2007-04-20 15:52:39 -0700
committerDavid S. Miller <davem@sunset.davemloft.net>2007-04-25 22:29:09 -0700
commitb881ef7603230550aa0150b22af94089f07ab00d (patch)
treeec74ff083cc84590e7a48510bb912821bb6cab6c /net/ipv6
parentfd44de7cc1d430caef91ad9aecec9ff000fe86f8 (diff)
downloadlinux-b881ef7603230550aa0150b22af94089f07ab00d.tar.gz
[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: John Heffner <jheffner@psc.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/ip6_output.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 4cfdad4e8356..5a5b7d4ad31c 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -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;