ipv4: Generalize ip_do_redirect() and hook into new dst_ops->redirect.

All of the redirect acceptance policy is now contained within.

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

2 files changed, 55 insertions, 40 deletions

diff --git a/include/net/dst_ops.h b/include/net/dst_ops.h
index 4badc86e45d1..085931fa7ce0 100644
--- a/include/net/dst_ops.h
+++ b/include/net/dst_ops.h
@@ -25,6 +25,7 @@ struct dst_ops {
         struct dst_entry *      (*negative_advice)(struct dst_entry *);
         void                    (*link_failure)(struct sk_buff *);
         void                    (*update_pmtu)(struct dst_entry *dst, u32 mtu);
+        void                    (*redirect)(struct dst_entry *dst, struct sk_buff *skb);
         int                     (*local_out)(struct sk_buff *skb);
         struct neighbour *      (*neigh_lookup)(const struct dst_entry *dst,
                                                 struct sk_buff *skb,
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index f8921b448c39..f3d25656ddb0 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -149,6 +149,7 @@ static void		 ipv4_dst_destroy(struct dst_entry *dst);
 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst);
 static void              ipv4_link_failure(struct sk_buff *skb);
 static void              ip_rt_update_pmtu(struct dst_entry *dst, u32 mtu);
+static void              ip_do_redirect(struct dst_entry *dst, struct sk_buff *skb);
 static int rt_garbage_collect(struct dst_ops *ops);
 
 static void ipv4_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
@@ -179,6 +180,7 @@ static struct dst_ops ipv4_dst_ops = {
         .negative_advice =      ipv4_negative_advice,
         .link_failure =         ipv4_link_failure,
         .update_pmtu =          ip_rt_update_pmtu,
+        .redirect =             ip_do_redirect,
         .local_out =            __ip_local_out,
         .neigh_lookup =         ipv4_neigh_lookup,
 };
@@ -1271,42 +1273,18 @@ static void rt_del(unsigned int hash, struct rtable *rt)
         spin_unlock_bh(rt_hash_lock_addr(hash));
 }
 
-static void ip_do_redirect(struct rtable *rt, __be32 old_gw, __be32 new_gw)
-{
-        struct neighbour *n;
-
-        if (rt->rt_gateway != old_gw)
-                return;
-
-        n = ipv4_neigh_lookup(&rt->dst, NULL, &new_gw);
-        if (n) {
-                if (!(n->nud_state & NUD_VALID)) {
-                        neigh_event_send(n, NULL);
-                } else {
-                        rt->rt_gateway = new_gw;
-                        rt->rt_flags |= RTCF_REDIRECTED;
-                        call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
-                }
-                neigh_release(n);
-        }
-}
-
-/* called in rcu_read_lock() section */
-void ip_rt_redirect(struct sk_buff *skb, __be32 new_gw)
+static void ip_do_redirect(struct dst_entry *dst, struct sk_buff *skb)
 {
         const struct iphdr *iph = (const struct iphdr *) skb->data;
+        __be32 new_gw = icmp_hdr(skb)->un.gateway;
         __be32 old_gw = ip_hdr(skb)->saddr;
+        struct net_device *dev = skb->dev;
         __be32 daddr = iph->daddr;
         __be32 saddr = iph->saddr;
-        struct net_device *dev = skb->dev;
-        struct in_device *in_dev = __in_dev_get_rcu(dev);
-        int    ikeys[2] = { dev->ifindex, 0 };
-        __be32 skeys[2] = { saddr, 0 };
+        struct in_device *in_dev;
+        struct neighbour *n;
+        struct rtable *rt;
         struct net *net;
-        int s, i;
-
-        if (!in_dev)
-                return;
 
         switch (icmp_hdr(skb)->code & 7) {
         case ICMP_REDIR_NET:
@@ -1319,6 +1297,14 @@ void ip_rt_redirect(struct sk_buff *skb, __be32 new_gw)
                 return;
         }
 
+        rt = (struct rtable *) dst;
+        if (rt->rt_gateway != old_gw)
+                return;
+
+        in_dev = __in_dev_get_rcu(dev);
+        if (!in_dev)
+                return;
+
         net = dev_net(dev);
         if (new_gw == old_gw || !IN_DEV_RX_REDIRECTS(in_dev) ||
             ipv4_is_multicast(new_gw) || ipv4_is_lbcast(new_gw) ||
@@ -1335,6 +1321,43 @@ void ip_rt_redirect(struct sk_buff *skb, __be32 new_gw)
                         goto reject_redirect;
         }
 
+        n = ipv4_neigh_lookup(dst, NULL, &new_gw);
+        if (n) {
+                if (!(n->nud_state & NUD_VALID)) {
+                        neigh_event_send(n, NULL);
+                } else {
+                        rt->rt_gateway = new_gw;
+                        rt->rt_flags |= RTCF_REDIRECTED;
+                        call_netevent_notifiers(NETEVENT_NEIGH_UPDATE, n);
+                }
+                neigh_release(n);
+        }
+        return;
+
+reject_redirect:
+#ifdef CONFIG_IP_ROUTE_VERBOSE
+        if (IN_DEV_LOG_MARTIANS(in_dev))
+                net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
+                                     "  Advised path = %pI4 -> %pI4\n",
+                                     &old_gw, dev->name, &new_gw,
+                                     &saddr, &daddr);
+#endif
+        ;
+}
+
+/* called in rcu_read_lock() section */
+void ip_rt_redirect(struct sk_buff *skb, __be32 new_gw)
+{
+        const struct iphdr *iph = (const struct iphdr *) skb->data;
+        __be32 daddr = iph->daddr;
+        __be32 saddr = iph->saddr;
+        struct net_device *dev = skb->dev;
+        int    ikeys[2] = { dev->ifindex, 0 };
+        __be32 skeys[2] = { saddr, 0 };
+        struct net *net;
+        int s, i;
+
+        net = dev_net(dev);
         for (s = 0; s < 2; s++) {
                 for (i = 0; i < 2; i++) {
                         unsigned int hash;
@@ -1358,21 +1381,12 @@ void ip_rt_redirect(struct sk_buff *skb, __be32 new_gw)
                                     rt->dst.dev != dev)
                                         continue;
 
-                                ip_do_redirect(rt, old_gw, new_gw);
+                                ip_do_redirect(&rt->dst, skb);
                         }
                 }
         }
         return;
 
-reject_redirect:
-#ifdef CONFIG_IP_ROUTE_VERBOSE
-        if (IN_DEV_LOG_MARTIANS(in_dev))
-                net_info_ratelimited("Redirect from %pI4 on %s about %pI4 ignored\n"
-                                     "  Advised path = %pI4 -> %pI4\n",
-                                     &old_gw, dev->name, &new_gw,
-                                     &saddr, &daddr);
-#endif
-        ;
 }
 
 static struct dst_entry *ipv4_negative_advice(struct dst_entry *dst)