6 files changed, 99 insertions, 41 deletions

diff --git a/include/net/dst.h b/include/net/dst.h
index 59c5d18cc385..ff4da42fcfc6 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -36,7 +36,11 @@ struct dst_entry {
         struct net_device       *dev;
         struct  dst_ops         *ops;
         unsigned long           _metrics;
-        unsigned long           expires;
+        union {
+                unsigned long           expires;
+                /* point to where the dst_entry copied from */
+                struct dst_entry        *from;
+        };
         struct dst_entry        *path;
         struct neighbour __rcu  *_neighbour;
 #ifdef CONFIG_XFRM
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index b26bb8101981..c64778fd5e13 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -123,6 +123,48 @@ static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
         return ((struct rt6_info *)dst)->rt6i_idev;
 }
 
+static inline void rt6_clean_expires(struct rt6_info *rt)
+{
+        if (!(rt->rt6i_flags & RTF_EXPIRES) && rt->dst.from)
+                dst_release(rt->dst.from);
+
+        rt->rt6i_flags &= ~RTF_EXPIRES;
+        rt->dst.expires = 0;
+}
+
+static inline void rt6_set_expires(struct rt6_info *rt, unsigned long expires)
+{
+        if (!(rt->rt6i_flags & RTF_EXPIRES) && rt->dst.from)
+                dst_release(rt->dst.from);
+
+        rt->rt6i_flags |= RTF_EXPIRES;
+        rt->dst.expires = 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);
+
+        dst_set_expires(&rt->dst, timeout);
+        rt->rt6i_flags |= RTF_EXPIRES;
+}
+
+static inline void rt6_set_from(struct rt6_info *rt, struct rt6_info *from)
+{
+        struct dst_entry *new = (struct dst_entry *) from;
+
+        if (!(rt->rt6i_flags & RTF_EXPIRES) && rt->dst.from) {
+                if (new == rt->dst.from)
+                        return;
+                dst_release(rt->dst.from);
+        }
+
+        rt->rt6i_flags &= ~RTF_EXPIRES;
+        rt->dst.from = new;
+        dst_hold(new);
+}
+
 struct fib6_walker_t {
         struct list_head lh;
         struct fib6_node *root, *node;
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 6a3bb6077e19..7d5cb975cc6f 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -803,8 +803,7 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp)
                                 ip6_del_rt(rt);
                                 rt = NULL;
                         } else if (!(rt->rt6i_flags & RTF_EXPIRES)) {
-                                rt->dst.expires = expires;
-                                rt->rt6i_flags |= RTF_EXPIRES;
+                                rt6_set_expires(rt, expires);
                         }
                 }
                 dst_release(&rt->dst);
@@ -1887,11 +1886,9 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)
                                 rt = NULL;
                         } else if (addrconf_finite_timeout(rt_expires)) {
                                 /* not infinity */
-                                rt->dst.expires = jiffies + rt_expires;
-                                rt->rt6i_flags |= RTF_EXPIRES;
+                                rt6_set_expires(rt, jiffies + rt_expires);
                         } else {
-                                rt->rt6i_flags &= ~RTF_EXPIRES;
-                                rt->dst.expires = 0;
+                                rt6_clean_expires(rt);
                         }
                 } else if (valid_lft) {
                         clock_t expires = 0;
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 5b27fbcae346..93717435013e 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -673,11 +673,10 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct rt6_info *rt,
                                             &rt->rt6i_gateway)) {
                                 if (!(iter->rt6i_flags & RTF_EXPIRES))
                                         return -EEXIST;
-                                iter->dst.expires = rt->dst.expires;
-                                if (!(rt->rt6i_flags & RTF_EXPIRES)) {
-                                        iter->rt6i_flags &= ~RTF_EXPIRES;
-                                        iter->dst.expires = 0;
-                                }
+                                if (!(rt->rt6i_flags & RTF_EXPIRES))
+                                        rt6_clean_expires(iter);
+                                else
+                                        rt6_set_expires(iter, rt->dst.expires);
                                 return -EEXIST;
                         }
                 }
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 3dcdb81ec3e8..176b469322ac 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1264,8 +1264,7 @@ static void ndisc_router_discovery(struct sk_buff *skb)
         }
 
         if (rt)
-                rt->dst.expires = jiffies + (HZ * lifetime);
-
+                rt6_set_expires(rt, jiffies + (HZ * lifetime));
         if (ra_msg->icmph.icmp6_hop_limit) {
                 in6_dev->cnf.hop_limit = ra_msg->icmph.icmp6_hop_limit;
                 if (rt)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 3992e26a6039..bc4888d902b2 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -62,7 +62,7 @@
 #include <linux/sysctl.h>
 #endif
 
-static struct rt6_info *ip6_rt_copy(const struct rt6_info *ort,
+static struct rt6_info *ip6_rt_copy(struct rt6_info *ort,
                                     const struct in6_addr *dest);
 static struct dst_entry *ip6_dst_check(struct dst_entry *dst, u32 cookie);
 static unsigned int      ip6_default_advmss(const struct dst_entry *dst);
@@ -285,6 +285,10 @@ static void ip6_dst_destroy(struct dst_entry *dst)
                 rt->rt6i_idev = NULL;
                 in6_dev_put(idev);
         }
+
+        if (!(rt->rt6i_flags & RTF_EXPIRES) && dst->from)
+                dst_release(dst->from);
+
         if (peer) {
                 rt->rt6i_peer = NULL;
                 inet_putpeer(peer);
@@ -329,8 +333,17 @@ static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 
 static __inline__ int rt6_check_expired(const struct rt6_info *rt)
 {
-        return (rt->rt6i_flags & RTF_EXPIRES) &&
-                time_after(jiffies, rt->dst.expires);
+        struct rt6_info *ort = NULL;
+
+        if (rt->rt6i_flags & RTF_EXPIRES) {
+                if (time_after(jiffies, rt->dst.expires))
+                        return 1;
+        } else if (rt->dst.from) {
+                ort = (struct rt6_info *) rt->dst.from;
+                return (ort->rt6i_flags & RTF_EXPIRES) &&
+                        time_after(jiffies, ort->dst.expires);
+        }
+        return 0;
 }
 
 static inline int rt6_need_strict(const struct in6_addr *daddr)
@@ -620,12 +633,11 @@ int rt6_route_rcv(struct net_device *dev, u8 *opt, int len,
                                  (rt->rt6i_flags & ~RTF_PREF_MASK) | RTF_PREF(pref);
 
         if (rt) {
-                if (!addrconf_finite_timeout(lifetime)) {
-                        rt->rt6i_flags &= ~RTF_EXPIRES;
-                } else {
-                        rt->dst.expires = jiffies + HZ * lifetime;
-                        rt->rt6i_flags |= RTF_EXPIRES;
-                }
+                if (!addrconf_finite_timeout(lifetime))
+                        rt6_clean_expires(rt);
+                else
+                        rt6_set_expires(rt, jiffies + HZ * lifetime);
+
                 dst_release(&rt->dst);
         }
         return 0;
@@ -730,7 +742,7 @@ int ip6_ins_rt(struct rt6_info *rt)
         return __ip6_ins_rt(rt, &info);
 }
 
-static struct rt6_info *rt6_alloc_cow(const struct rt6_info *ort,
+static struct rt6_info *rt6_alloc_cow(struct rt6_info *ort,
                                       const struct in6_addr *daddr,
                                       const struct in6_addr *saddr)
 {
@@ -954,10 +966,10 @@ struct dst_entry *ip6_blackhole_route(struct net *net, struct dst_entry *dst_ori
                 rt->rt6i_idev = ort->rt6i_idev;
                 if (rt->rt6i_idev)
                         in6_dev_hold(rt->rt6i_idev);
-                rt->dst.expires = 0;
 
                 rt->rt6i_gateway = ort->rt6i_gateway;
-                rt->rt6i_flags = ort->rt6i_flags & ~RTF_EXPIRES;
+                rt->rt6i_flags = ort->rt6i_flags;
+                rt6_clean_expires(rt);
                 rt->rt6i_metric = 0;
 
                 memcpy(&rt->rt6i_dst, &ort->rt6i_dst, sizeof(struct rt6key));
@@ -1019,10 +1031,9 @@ static void ip6_link_failure(struct sk_buff *skb)
 
         rt = (struct rt6_info *) skb_dst(skb);
         if (rt) {
-                if (rt->rt6i_flags & RTF_CACHE) {
-                        dst_set_expires(&rt->dst, 0);
-                        rt->rt6i_flags |= RTF_EXPIRES;
-                } else if (rt->rt6i_node && (rt->rt6i_flags & RTF_DEFAULT))
+                if (rt->rt6i_flags & RTF_CACHE)
+                        rt6_update_expires(rt, 0);
+                else if (rt->rt6i_node && (rt->rt6i_flags & RTF_DEFAULT))
                         rt->rt6i_node->fn_sernum = -1;
         }
 }
@@ -1289,9 +1300,12 @@ int ip6_route_add(struct fib6_config *cfg)
         }
 
         rt->dst.obsolete = -1;
-        rt->dst.expires = (cfg->fc_flags & RTF_EXPIRES) ?
-                                jiffies + clock_t_to_jiffies(cfg->fc_expires) :
-                                0;
+
+        if (cfg->fc_flags & RTF_EXPIRES)
+                rt6_set_expires(rt, jiffies +
+                                clock_t_to_jiffies(cfg->fc_expires));
+        else
+                rt6_clean_expires(rt);
 
         if (cfg->fc_protocol == RTPROT_UNSPEC)
                 cfg->fc_protocol = RTPROT_BOOT;
@@ -1736,8 +1750,8 @@ again:
                         features |= RTAX_FEATURE_ALLFRAG;
                         dst_metric_set(&rt->dst, RTAX_FEATURES, features);
                 }
-                dst_set_expires(&rt->dst, net->ipv6.sysctl.ip6_rt_mtu_expires);
-                rt->rt6i_flags |= RTF_MODIFIED|RTF_EXPIRES;
+                rt6_update_expires(rt, net->ipv6.sysctl.ip6_rt_mtu_expires);
+                rt->rt6i_flags |= RTF_MODIFIED;
                 goto out;
         }
 
@@ -1765,9 +1779,8 @@ again:
                  * which is 10 mins. After 10 mins the decreased pmtu is expired
                  * and detecting PMTU increase will be automatically happened.
                  */
-                dst_set_expires(&nrt->dst, net->ipv6.sysctl.ip6_rt_mtu_expires);
-                nrt->rt6i_flags |= RTF_DYNAMIC|RTF_EXPIRES;
-
+                rt6_update_expires(nrt, net->ipv6.sysctl.ip6_rt_mtu_expires);
+                nrt->rt6i_flags |= RTF_DYNAMIC;
                 ip6_ins_rt(nrt);
         }
 out:
@@ -1799,7 +1812,7 @@ void rt6_pmtu_discovery(const struct in6_addr *daddr, const struct in6_addr *sad
  *      Misc support functions
  */
 
-static struct rt6_info *ip6_rt_copy(const struct rt6_info *ort,
+static struct rt6_info *ip6_rt_copy(struct rt6_info *ort,
                                     const struct in6_addr *dest)
 {
         struct net *net = dev_net(ort->dst.dev);
@@ -1819,10 +1832,14 @@ static struct rt6_info *ip6_rt_copy(const struct rt6_info *ort,
                 if (rt->rt6i_idev)
                         in6_dev_hold(rt->rt6i_idev);
                 rt->dst.lastuse = jiffies;
-                rt->dst.expires = 0;
 
                 rt->rt6i_gateway = ort->rt6i_gateway;
-                rt->rt6i_flags = ort->rt6i_flags & ~RTF_EXPIRES;
+                rt->rt6i_flags = ort->rt6i_flags;
+                if ((ort->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF)) ==
+                    (RTF_DEFAULT | RTF_ADDRCONF))
+                        rt6_set_from(rt, ort);
+                else
+                        rt6_clean_expires(rt);
                 rt->rt6i_metric = 0;
 
 #ifdef CONFIG_IPV6_SUBTREES