ipv4: Fix inetpeer expire time information

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>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 3 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 155138d8ec8b..511f4a75149c 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2845,7 +2845,7 @@ 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;
 
@@ -2902,8 +2902,12 @@ 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)) {