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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
parentfd44de7cc1d430caef91ad9aecec9ff000fe86f8 (diff)
[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>
-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;