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: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 741df67a..132e0df 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2187,8 +2187,18 @@
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 @@
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))