Commit ee9a8f7a authored by Steffen Klassert's avatar Steffen Klassert Committed by David S. Miller
Browse files

ipv4: Don't report stale pmtu values to userspace 



We report cached pmtu values even if they are already expired.
Change this to not report these values after they are expired
and fix a race in the expire time calculation, as suggested by
Eric Dumazet.

Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7f92d334

net/ipv4/route.c

+11 −8
Original line number Diff line number Diff line
@@ -2187,8 +2187,18 @@ static int rt_fill_info(struct net *net, __be32 dst, __be32 src, 
	    nla_put_be32(skb, RTA_GATEWAY, rt->rt_gateway))

		goto nla_put_failure;



	expires = rt->dst.expires;

	if (expires) {

		unsigned long now = jiffies;



		if (time_before(now, expires))

			expires -= now;

		else

			expires = 0;

	}



	memcpy(metrics, dst_metrics_ptr(&rt->dst), sizeof(metrics));

	if (rt->rt_pmtu)

	if (rt->rt_pmtu && expires)

		metrics[RTAX_MTU - 1] = rt->rt_pmtu;

	if (rtnetlink_put_metrics(skb, metrics) < 0)

		goto nla_put_failure;
@@ -2198,13 +2208,6 @@ static int rt_fill_info(struct net *net, __be32 dst, __be32 src, 
		goto nla_put_failure;



	error = rt->dst.error;

	expires = rt->dst.expires;

	if (expires) {

		if (time_before(jiffies, expires))

			expires -= jiffies;

		else

			expires = 0;

	}



	if (rt_is_input_route(rt)) {

		if (nla_put_u32(skb, RTA_IIF, rt->rt_iif))