[PATCH 4/4] ipv4: Fix inetpeer expire time information

[Steffen Klassert <steffen.klassert@secunet.com>]

As we update the learned pmtu informations on demand, we might
report a nagative expiration time value to userspace if the
pmtu informations are already expired and we have not send a
packet to that inetpeer after expiration. With this patch we
send a expire time of null to userspace after expiration
until the next packet is send to that inetpeer.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 net/ipv4/route.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index cda370c..501a3c0 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2832,7 +2832,7 @@ static int rt_fill_info(struct net *net,
 	struct rtable *rt = skb_rtable(skb);
 	struct rtmsg *r;
 	struct nlmsghdr *nlh;
-	long expires = 0;
+	unsigned long expires = 0;
 	const struct inet_peer *peer = rt->peer;
 	u32 id = 0, ts = 0, tsage = 0, error;
 
@@ -2889,8 +2889,12 @@ static int rt_fill_info(struct net *net,
 			tsage = get_seconds() - peer->tcp_ts_stamp;
 		}
 		expires = ACCESS_ONCE(peer->pmtu_expires);
-		if (expires)
-			expires -= jiffies;
+		if (expires) {
+			if (time_before(jiffies, expires))
+				expires -= jiffies;
+			else
+				expires = 0;
+		}
 	}
 
 	if (rt_is_input_route(rt)) {
-- 
1.7.0.4