Commit d3052b55 authored Dec 11, 2010 by Andrey Vagin Committed by David S. Miller Dec 16, 2010

ipv6: delete expired route in ip6_pmtu_deliver



The first big packets sent to a "low-MTU" client correctly
triggers the creation of a temporary route containing the reduced MTU.

But after the temporary route has expired, new ICMP6 "packet too big"
will be sent, rt6_pmtu_discovery will find the previous EXPIRED route
check that its mtu isn't bigger then in icmp packet and do nothing
before the temporary route will not deleted by gc.

I make the simple experiment:
while :; do
    time ( dd if=/dev/zero bs=10K count=1 | ssh hostname dd of=/dev/null ) || break;
done

The "time" reports real 0m0.197s if a temporary route isn't expired, but
it reports real 0m52.837s (!!!!) immediately after a temporare route has
expired.

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent af3e5bd5

net/ipv6/route.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -1565,11 +1565,16 @@ static void rt6_do_pmtu_disc(struct in6_addr daddr, struct in6_addr saddr,
		{
		struct rt6_info rt, nrt;
		int allfrag = 0;

		again:
		rt = rt6_lookup(net, daddr, saddr, ifindex, 0);
		if (rt == NULL)
		return;

		if (rt6_check_expired(rt)) {
		ip6_del_rt(rt);
		goto again;
		}

		if (pmtu >= dst_mtu(&rt->dst))
		goto out;