ipv6: fix rt6_update_expires

Commit 1716a961 (ipv6: fix problem with expired dst cache) broke PMTU
discovery. rt6_update_expires() calls dst_set_expires(), which only updates
dst->expires if it has not been set previously (expires == 0) or if the new
expires is earlier than the current dst->expires.

rt6_update_expires() needs to zero rt->dst.expires, otherwise it will contain
ivalid data left over from rt->dst.from and will confuse dst_set_expires().

Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index c64778f..cb8da1d 100644 (file)
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -143,8 +143,14 @@ static inline void rt6_set_expires(struct rt6_info *rt, unsigned long expires)
 
 static inline void rt6_update_expires(struct rt6_info *rt, int timeout)
 {
-       if (!(rt->rt6i_flags & RTF_EXPIRES) && rt->dst.from)
-               dst_release(rt->dst.from);
+       if (!(rt->rt6i_flags & RTF_EXPIRES)) {
+               if (rt->dst.from)
+                       dst_release(rt->dst.from);
+               /* dst_set_expires relies on expires == 0 
+                * if it has not been set previously.
+                */
+               rt->dst.expires = 0;
+       }
 
        dst_set_expires(&rt->dst, timeout);
        rt->rt6i_flags |= RTF_EXPIRES;