route: check and remove route cache when we get route

Since the gc of ipv4 route was removed, the route cached would has
no chance to be removed, and even it has been timeout, it still could
be used, cause no code to check it's expires.

Fix this issue by checking  and removing route cache when we get route.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index 7029527725ddbb80f7b78e66565b69ad8aad5806..4079fc18ffe4643522178b394ed6d1b54d5a6093 100644 (file)
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -61,6 +61,7 @@ struct fib_nh_exception {
        struct rtable __rcu             *fnhe_rth_input;
        struct rtable __rcu             *fnhe_rth_output;
        unsigned long                   fnhe_stamp;
+       struct rcu_head                 rcu;
 };
 
 struct fnhe_hash_bucket {

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 85f184e429c63c8c426f58c779dc3544cf2e2a54..02c62299d717b9f6c38a5227e3b3ae376e0015b6 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -129,6 +129,7 @@ static int ip_rt_mtu_expires __read_mostly  = 10 * 60 * HZ;
 static int ip_rt_min_pmtu __read_mostly                = 512 + 20 + 20;
 static int ip_rt_min_advmss __read_mostly      = 256;
 
+static int ip_rt_gc_timeout __read_mostly      = RT_GC_TIMEOUT;
 /*
  *     Interface to generic destination cache.
  */
@@ -755,7 +756,7 @@ static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flow
                                struct fib_nh *nh = &FIB_RES_NH(res);
 
                                update_or_create_fnhe(nh, fl4->daddr, new_gw,
-                                                     0, 0);
+                                               0, jiffies + ip_rt_gc_timeout);
                        }
                        if (kill_route)
                                rt->dst.obsolete = DST_OBSOLETE_KILL;
@@ -1556,6 +1557,36 @@ static void ip_handle_martian_source(struct net_device *dev,
 #endif
 }
 
+static void ip_del_fnhe(struct fib_nh *nh, __be32 daddr)
+{
+       struct fnhe_hash_bucket *hash;
+       struct fib_nh_exception *fnhe, __rcu **fnhe_p;
+       u32 hval = fnhe_hashfun(daddr);
+
+       spin_lock_bh(&fnhe_lock);
+
+       hash = rcu_dereference_protected(nh->nh_exceptions,
+                                        lockdep_is_held(&fnhe_lock));
+       hash += hval;
+
+       fnhe_p = &hash->chain;
+       fnhe = rcu_dereference_protected(*fnhe_p, lockdep_is_held(&fnhe_lock));
+       while (fnhe) {
+               if (fnhe->fnhe_daddr == daddr) {
+                       rcu_assign_pointer(*fnhe_p, rcu_dereference_protected(
+                               fnhe->fnhe_next, lockdep_is_held(&fnhe_lock)));
+                       fnhe_flush_routes(fnhe);
+                       kfree_rcu(fnhe, rcu);
+                       break;
+               }
+               fnhe_p = &fnhe->fnhe_next;
+               fnhe = rcu_dereference_protected(fnhe->fnhe_next,
+                                                lockdep_is_held(&fnhe_lock));
+       }
+
+       spin_unlock_bh(&fnhe_lock);
+}
+
 /* called in rcu_read_lock() section */
 static int __mkroute_input(struct sk_buff *skb,
                           const struct fib_result *res,
@@ -1609,11 +1640,20 @@ static int __mkroute_input(struct sk_buff *skb,
 
        fnhe = find_exception(&FIB_RES_NH(*res), daddr);
        if (do_cache) {
-               if (fnhe)
+               if (fnhe) {
                        rth = rcu_dereference(fnhe->fnhe_rth_input);
-               else
-                       rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
+                       if (rth && rth->dst.expires &&
+                           time_after(jiffies, rth->dst.expires)) {
+                               ip_del_fnhe(&FIB_RES_NH(*res), daddr);
+                               fnhe = NULL;
+                       } else {
+                               goto rt_cache;
+                       }
+               }
+
+               rth = rcu_dereference(FIB_RES_NH(*res).nh_rth_input);
 
+rt_cache:
                if (rt_cache_valid(rth)) {
                        skb_dst_set_noref(skb, &rth->dst);
                        goto out;
@@ -2014,19 +2054,29 @@ static struct rtable *__mkroute_output(const struct fib_result *res,
                struct fib_nh *nh = &FIB_RES_NH(*res);
 
                fnhe = find_exception(nh, fl4->daddr);
-               if (fnhe)
+               if (fnhe) {
                        prth = &fnhe->fnhe_rth_output;
-               else {
-                       if (unlikely(fl4->flowi4_flags &
-                                    FLOWI_FLAG_KNOWN_NH &&
-                                    !(nh->nh_gw &&
-                                      nh->nh_scope == RT_SCOPE_LINK))) {
-                               do_cache = false;
-                               goto add;
+                       rth = rcu_dereference(*prth);
+                       if (rth && rth->dst.expires &&
+                           time_after(jiffies, rth->dst.expires)) {
+                               ip_del_fnhe(nh, fl4->daddr);
+                               fnhe = NULL;
+                       } else {
+                               goto rt_cache;
                        }
-                       prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
                }
+
+               if (unlikely(fl4->flowi4_flags &
+                            FLOWI_FLAG_KNOWN_NH &&
+                            !(nh->nh_gw &&
+                              nh->nh_scope == RT_SCOPE_LINK))) {
+                       do_cache = false;
+                       goto add;
+               }
+               prth = raw_cpu_ptr(nh->nh_pcpu_rth_output);
                rth = rcu_dereference(*prth);
+
+rt_cache:
                if (rt_cache_valid(rth)) {
                        dst_hold(&rth->dst);
                        return rth;
@@ -2569,7 +2619,6 @@ void ip_rt_multicast_event(struct in_device *in_dev)
 }
 
 #ifdef CONFIG_SYSCTL
-static int ip_rt_gc_timeout __read_mostly      = RT_GC_TIMEOUT;
 static int ip_rt_gc_interval __read_mostly  = 60 * HZ;
 static int ip_rt_gc_min_interval __read_mostly = HZ / 2;
 static int ip_rt_gc_elasticity __read_mostly   = 8;