ipv6: prepare fib6_age() for exception table

If all dst cache entries are stored in the exception table under the
main route, we have to go through them during fib6_age() when doing
garbage collecting.
Introduce a new function rt6_age_exception() which goes through all dst
entries in the exception table and remove those entries that are expired.
This function is called in fib6_age() so that all dst caches are also
garbage collected.

Signed-off-by: Wei Wang <weiwan@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index c4864c1e8f1363aa898293bf5461a488c200ffb0..11a79ef87a2838ad393a14a44f0813bad9b968b5 100644 (file)
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -29,6 +29,14 @@
 #define FIB6_TABLE_HASHSZ 1
 #endif
 
+#define RT6_DEBUG 2
+
+#if RT6_DEBUG >= 3
+#define RT6_TRACE(x...) pr_debug(x)
+#else
+#define RT6_TRACE(x...) do { ; } while (0)
+#endif
+
 struct rt6_info;
 
 struct fib6_config {
@@ -75,6 +83,11 @@ struct fib6_node {
        struct rcu_head         rcu;
 };
 
+struct fib6_gc_args {
+       int                     timeout;
+       int                     more;
+};
+
 #ifndef CONFIG_IPV6_SUBTREES
 #define FIB6_SUBTREE(fn)       NULL
 #else

diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h
index 3315605f34c97b1f612e286e16895e2cffbe230a..a0087fb9864bce9de3d169e5cf3a59ab6758e8be 100644 (file)
--- a/include/net/ip6_route.h
+++ b/include/net/ip6_route.h
@@ -97,6 +97,8 @@ int ip6_del_rt(struct rt6_info *);
 
 void rt6_flush_exceptions(struct rt6_info *rt);
 int rt6_remove_exception_rt(struct rt6_info *rt);
+void rt6_age_exceptions(struct rt6_info *rt, struct fib6_gc_args *gc_args,
+                       unsigned long now);
 
 static inline int ip6_route_get_saddr(struct net *net, struct rt6_info *rt,
                                      const struct in6_addr *daddr,

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 0ba4fbb2f85559203857a7ac781c5a2686ac685c..3afbe50f27797d2710b0053c3db31eaff90ffefc 100644 (file)
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -38,14 +38,6 @@
 #include <net/ip6_fib.h>
 #include <net/ip6_route.h>
 
-#define RT6_DEBUG 2
-
-#if RT6_DEBUG >= 3
-#define RT6_TRACE(x...) pr_debug(x)
-#else
-#define RT6_TRACE(x...) do { ; } while (0)
-#endif
-
 static struct kmem_cache *fib6_node_kmem __read_mostly;
 
 struct fib6_cleaner {
@@ -1890,12 +1882,6 @@ static void fib6_flush_trees(struct net *net)
  *     Garbage collection
  */
 
-struct fib6_gc_args
-{
-       int                     timeout;
-       int                     more;
-};
-
 static int fib6_age(struct rt6_info *rt, void *arg)
 {
        struct fib6_gc_args *gc_args = arg;
@@ -1904,9 +1890,6 @@ static int fib6_age(struct rt6_info *rt, void *arg)
        /*
         *      check addrconf expiration here.
         *      Routes are expired even if they are in use.
-        *
-        *      Also age clones. Note, that clones are aged out
-        *      only if they are not in use now.
         */
 
        if (rt->rt6i_flags & RTF_EXPIRES && rt->dst.expires) {
@@ -1915,6 +1898,9 @@ static int fib6_age(struct rt6_info *rt, void *arg)
                        return -1;
                }
                gc_args->more++;
+       /* The following part will soon be removed when the exception
+        * table is hooked up to store all cached routes.
+        */
        } else if (rt->rt6i_flags & RTF_CACHE) {
                if (time_after_eq(now, rt->dst.lastuse + gc_args->timeout))
                        rt->dst.obsolete = DST_OBSOLETE_KILL;
@@ -1940,6 +1926,12 @@ static int fib6_age(struct rt6_info *rt, void *arg)
                gc_args->more++;
        }
 
+       /*      Also age clones in the exception table.
+        *      Note, that clones are aged out
+        *      only if they are not in use now.
+        */
+       rt6_age_exceptions(rt, gc_args, now);
+
        return 0;
 }
 

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index e8e901589564960206b46f100e2d4720c67e8b53..d2dd55f58b5d1bf0ec84b15b51c2d315c0264f53 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1528,6 +1528,66 @@ static void rt6_exceptions_clean_tohost(struct rt6_info *rt,
        spin_unlock_bh(&rt6_exception_lock);
 }
 
+static void rt6_age_examine_exception(struct rt6_exception_bucket *bucket,
+                                     struct rt6_exception *rt6_ex,
+                                     struct fib6_gc_args *gc_args,
+                                     unsigned long now)
+{
+       struct rt6_info *rt = rt6_ex->rt6i;
+
+       if (atomic_read(&rt->dst.__refcnt) == 1 &&
+           time_after_eq(now, rt->dst.lastuse + gc_args->timeout)) {
+               RT6_TRACE("aging clone %p\n", rt);
+               rt6_remove_exception(bucket, rt6_ex);
+               return;
+       } else if (rt->rt6i_flags & RTF_GATEWAY) {
+               struct neighbour *neigh;
+               __u8 neigh_flags = 0;
+
+               neigh = dst_neigh_lookup(&rt->dst, &rt->rt6i_gateway);
+               if (neigh) {
+                       neigh_flags = neigh->flags;
+                       neigh_release(neigh);
+               }
+               if (!(neigh_flags & NTF_ROUTER)) {
+                       RT6_TRACE("purging route %p via non-router but gateway\n",
+                                 rt);
+                       rt6_remove_exception(bucket, rt6_ex);
+                       return;
+               }
+       }
+       gc_args->more++;
+}
+
+void rt6_age_exceptions(struct rt6_info *rt,
+                       struct fib6_gc_args *gc_args,
+                       unsigned long now)
+{
+       struct rt6_exception_bucket *bucket;
+       struct rt6_exception *rt6_ex;
+       struct hlist_node *tmp;
+       int i;
+
+       if (!rcu_access_pointer(rt->rt6i_exception_bucket))
+               return;
+
+       spin_lock_bh(&rt6_exception_lock);
+       bucket = rcu_dereference_protected(rt->rt6i_exception_bucket,
+                                   lockdep_is_held(&rt6_exception_lock));
+
+       if (bucket) {
+               for (i = 0; i < FIB6_EXCEPTION_BUCKET_SIZE; i++) {
+                       hlist_for_each_entry_safe(rt6_ex, tmp,
+                                                 &bucket->chain, hlist) {
+                               rt6_age_examine_exception(bucket, rt6_ex,
+                                                         gc_args, now);
+                       }
+                       bucket++;
+               }
+       }
+       spin_unlock_bh(&rt6_exception_lock);
+}
+
 struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
                               int oif, struct flowi6 *fl6, int flags)
 {