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>

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 155138d..511f4a7 100644 (file)
--- 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)) {