[IPV6]: Fix route lifetime.

The route expiration time is stored in rt6i_expires in jiffies.
The argument of rt6_route_add() for adding a route is not the
expiration time in jiffies nor in clock_t, but the lifetime
(or time left before expiration) in clock_t.

Because of the confusion, we sometimes saw several strange errors
(FAILs) in TAHI IPv6 Ready Logo Phase-2 Self Test.
The symptoms were analyzed by Mitsuru Chinen <CHINEN@jp.ibm.com>.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 12 insertions, 4 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 73a23b4130a5..4ea8cf7c0cc4 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1596,9 +1596,17 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len)
            not good.
          */
         if (valid_lft >= 0x7FFFFFFF/HZ)
-                rt_expires = 0;
+                rt_expires = 0x7FFFFFFF - (0x7FFFFFFF % HZ);
         else
-                rt_expires = jiffies + valid_lft * HZ;
+                rt_expires = valid_lft * HZ;
+
+        /*
+         * We convert this (in jiffies) to clock_t later.
+         * Avoid arithmetic overflow there as well.
+         * Overflow can happen only if HZ < USER_HZ.
+         */
+        if (HZ < USER_HZ && rt_expires > 0x7FFFFFFF / USER_HZ)
+                rt_expires = 0x7FFFFFFF / USER_HZ;
 
         if (pinfo->onlink) {
                 struct rt6_info *rt;
@@ -1610,12 +1618,12 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len)
                                         ip6_del_rt(rt, NULL, NULL, NULL);
                                         rt = NULL;
                                 } else {
-                                        rt->rt6i_expires = rt_expires;
+                                        rt->rt6i_expires = jiffies + rt_expires;
                                 }
                         }
                 } else if (valid_lft) {
                         addrconf_prefix_route(&pinfo->prefix, pinfo->prefix_len,
-                                              dev, rt_expires, RTF_ADDRCONF|RTF_EXPIRES|RTF_PREFIX_RT);
+                                              dev, jiffies_to_clock_t(rt_expires), RTF_ADDRCONF|RTF_EXPIRES|RTF_PREFIX_RT);
                 }
                 if (rt)
                         dst_release(&rt->u.dst);