ipv4: Cache learned redirect information in inetpeer.

Note that we do not generate the redirect netevent any longer,
because we don't create a new cached route.

Instead, once the new neighbour is bound to the cached route,
we emit a neigh update event instead.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 42 insertions, 94 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 11faf14c7430..756f5443b5f7 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1294,13 +1294,8 @@ static void rt_del(unsigned hash, struct rtable *rt)
 void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
                     __be32 saddr, struct net_device *dev)
 {
-        int i, k;
         struct in_device *in_dev = __in_dev_get_rcu(dev);
-        struct rtable *rth;
-        struct rtable __rcu **rthp;
-        __be32  skeys[2] = { saddr, 0 };
-        int  ikeys[2] = { dev->ifindex, 0 };
-        struct netevent_redirect netevent;
+        struct inet_peer *peer;
         struct net *net;
 
         if (!in_dev)
@@ -1312,9 +1307,6 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
             ipv4_is_zeronet(new_gw))
                 goto reject_redirect;
 
-        if (!rt_caching(net))
-                goto reject_redirect;
-
         if (!IN_DEV_SHARED_MEDIA(in_dev)) {
                 if (!inet_addr_onlink(in_dev, new_gw, old_gw))
                         goto reject_redirect;
@@ -1325,93 +1317,13 @@ void ip_rt_redirect(__be32 old_gw, __be32 daddr, __be32 new_gw,
                         goto reject_redirect;
         }
 
-        for (i = 0; i < 2; i++) {
-                for (k = 0; k < 2; k++) {
-                        unsigned hash = rt_hash(daddr, skeys[i], ikeys[k],
-                                                rt_genid(net));
-
-                        rthp = &rt_hash_table[hash].chain;
-
-                        while ((rth = rcu_dereference(*rthp)) != NULL) {
-                                struct rtable *rt;
-
-                                if (rth->fl.fl4_dst != daddr ||
-                                    rth->fl.fl4_src != skeys[i] ||
-                                    rth->fl.oif != ikeys[k] ||
-                                    rt_is_input_route(rth) ||
-                                    rt_is_expired(rth) ||
-                                    !net_eq(dev_net(rth->dst.dev), net)) {
-                                        rthp = &rth->dst.rt_next;
-                                        continue;
-                                }
-
-                                if (rth->rt_dst != daddr ||
-                                    rth->rt_src != saddr ||
-                                    rth->dst.error ||
-                                    rth->rt_gateway != old_gw ||
-                                    rth->dst.dev != dev)
-                                        break;
-
-                                dst_hold(&rth->dst);
-
-                                rt = dst_alloc(&ipv4_dst_ops);
-                                if (rt == NULL) {
-                                        ip_rt_put(rth);
-                                        return;
-                                }
-
-                                /* Copy all the information. */
-                                *rt = *rth;
-                                rt->dst.__use           = 1;
-                                atomic_set(&rt->dst.__refcnt, 1);
-                                rt->dst.child           = NULL;
-                                if (rt->dst.dev)
-                                        dev_hold(rt->dst.dev);
-                                rt->dst.obsolete        = -1;
-                                rt->dst.lastuse = jiffies;
-                                rt->dst.path            = &rt->dst;
-                                rt->dst.neighbour       = NULL;
-                                rt->dst.hh              = NULL;
-#ifdef CONFIG_XFRM
-                                rt->dst.xfrm            = NULL;
-#endif
-                                rt->rt_genid            = rt_genid(net);
-                                rt->rt_flags            |= RTCF_REDIRECTED;
-
-                                /* Gateway is different ... */
-                                rt->rt_gateway          = new_gw;
-
-                                /* Redirect received -> path was valid */
-                                dst_confirm(&rth->dst);
-
-                                if (rt->peer)
-                                        atomic_inc(&rt->peer->refcnt);
-                                if (rt->fi)
-                                        atomic_inc(&rt->fi->fib_clntref);
-
-                                if (arp_bind_neighbour(&rt->dst) ||
-                                    !(rt->dst.neighbour->nud_state &
-                                            NUD_VALID)) {
-                                        if (rt->dst.neighbour)
-                                                neigh_event_send(rt->dst.neighbour, NULL);
-                                        ip_rt_put(rth);
-                                        rt_drop(rt);
-                                        goto do_next;
-                                }
+        peer = inet_getpeer_v4(daddr, 1);
+        if (peer) {
+                peer->redirect_learned.a4 = new_gw;
 
-                                netevent.old = &rth->dst;
-                                netevent.new = &rt->dst;
-                                call_netevent_notifiers(NETEVENT_REDIRECT,
-                                                        &netevent);
+                inet_putpeer(peer);
 
-                                rt_del(hash, rth);
-                                if (!rt_intern_hash(hash, rt, &rt, NULL, rt->fl.oif))
-                                        ip_rt_put(rt);
-                                goto do_next;
-                        }
-                do_next:
-                        ;
-                }
+                atomic_inc(&__rt_peer_genid);
         }
         return;
 
@@ -1678,6 +1590,31 @@ static void ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu)
         }
 }
 
+static int check_peer_redir(struct dst_entry *dst, struct inet_peer *peer)
+{
+        struct rtable *rt = (struct rtable *) dst;
+        __be32 orig_gw = rt->rt_gateway;
+
+        dst_confirm(&rt->dst);
+
+        neigh_release(rt->dst.neighbour);
+        rt->dst.neighbour = NULL;
+
+        rt->rt_gateway = peer->redirect_learned.a4;
+        if (arp_bind_neighbour(&rt->dst) ||
+            !(rt->dst.neighbour->nud_state & NUD_VALID)) {
+                if (rt->dst.neighbour)
+                        neigh_event_send(rt->dst.neighbour, NULL);
+                rt->rt_gateway = orig_gw;
+                return -EAGAIN;
+        } else {
+                rt->rt_flags |= RTCF_REDIRECTED;
+                call_netevent_notifiers(NETEVENT_NEIGH_UPDATE,
+                                        rt->dst.neighbour);
+        }
+        return 0;
+}
+
 static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
 {
         struct rtable *rt = (struct rtable *) dst;
@@ -1694,6 +1631,12 @@ static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
                 if (peer && peer->pmtu_expires)
                         check_peer_pmtu(dst, peer);
 
+                if (peer && peer->redirect_learned.a4 &&
+                    peer->redirect_learned.a4 != rt->rt_gateway) {
+                        if (check_peer_redir(dst, peer))
+                                return NULL;
+                }
+
                 rt->rt_peer_genid = rt_peer_genid();
         }
         return dst;
@@ -1830,6 +1773,11 @@ static void rt_init_metrics(struct rtable *rt, struct fib_info *fi)
 
                 if (peer->pmtu_expires)
                         check_peer_pmtu(&rt->dst, peer);
+                if (peer->redirect_learned.a4 &&
+                    peer->redirect_learned.a4 != rt->rt_gateway) {
+                        rt->rt_gateway = peer->redirect_learned.a4;
+                        rt->rt_flags |= RTCF_REDIRECTED;
+                }
         } else {
                 if (fi->fib_metrics != (u32 *) dst_default_metrics) {
                         rt->fi = fi;