net: Add optional SKB arg to dst_ops->neigh_lookup().

Causes the handler to use the daddr in the ipv4/ipv6 header when
the route gateway is unspecified (local subnet).

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

7 files changed, 43 insertions, 15 deletions

diff --git a/include/net/dst.h b/include/net/dst.h
index 84e7a3ff968d..295a70547e7d 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -420,7 +420,13 @@ static inline int dst_neigh_output(struct dst_entry *dst, struct neighbour *n,
 
 static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr)
 {
-        return dst->ops->neigh_lookup(dst, daddr);
+        return dst->ops->neigh_lookup(dst, NULL, daddr);
+}
+
+static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst,
+                                                     struct sk_buff *skb)
+{
+        return dst->ops->neigh_lookup(dst, skb, NULL);
 }
 
 static inline void dst_link_failure(struct sk_buff *skb)
diff --git a/include/net/dst_ops.h b/include/net/dst_ops.h
index 3682a0a076c1..4badc86e45d1 100644
--- a/include/net/dst_ops.h
+++ b/include/net/dst_ops.h
@@ -26,7 +26,9 @@ struct dst_ops {
         void                    (*link_failure)(struct sk_buff *);
         void                    (*update_pmtu)(struct dst_entry *dst, u32 mtu);
         int                     (*local_out)(struct sk_buff *skb);
-        struct neighbour *      (*neigh_lookup)(const struct dst_entry *dst, const void *daddr);
+        struct neighbour *      (*neigh_lookup)(const struct dst_entry *dst,
+                                                struct sk_buff *skb,
+                                                const void *daddr);
 
         struct kmem_cache       *kmem_cachep;
 
diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index 20fa719889ee..4378775432b6 100644
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -120,7 +120,9 @@ static u32 *fake_cow_metrics(struct dst_entry *dst, unsigned long old)
         return NULL;
 }
 
-static struct neighbour *fake_neigh_lookup(const struct dst_entry *dst, const void *daddr)
+static struct neighbour *fake_neigh_lookup(const struct dst_entry *dst,
+                                           struct sk_buff *skb,
+                                           const void *daddr)
 {
         return NULL;
 }
diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
index 2493ed5bfecd..60e4c6e1bac0 100644
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -117,7 +117,9 @@ static void dn_dst_destroy(struct dst_entry *);
 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
 static void dn_dst_link_failure(struct sk_buff *);
 static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu);
-static struct neighbour *dn_dst_neigh_lookup(const struct dst_entry *dst, const void *daddr);
+static struct neighbour *dn_dst_neigh_lookup(const struct dst_entry *dst,
+                                             struct sk_buff *skb,
+                                             const void *daddr);
 static int dn_route_input(struct sk_buff *);
 static void dn_run_flush(unsigned long dummy);
 
@@ -828,7 +830,9 @@ static unsigned int dn_dst_mtu(const struct dst_entry *dst)
         return mtu ? : dst->dev->mtu;
 }
 
-static struct neighbour *dn_dst_neigh_lookup(const struct dst_entry *dst, const void *daddr)
+static struct neighbour *dn_dst_neigh_lookup(const struct dst_entry *dst,
+                                             struct sk_buff *skb,
+                                             const void *daddr)
 {
         return __neigh_lookup_errno(&dn_neigh_table, daddr, dst->dev);
 }
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index bae36386e722..7453dfcdb439 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -188,7 +188,9 @@ static u32 *ipv4_cow_metrics(struct dst_entry *dst, unsigned long old)
         return p;
 }
 
-static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, const void *daddr);
+static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
+                                           struct sk_buff *skb,
+                                           const void *daddr);
 
 static struct dst_ops ipv4_dst_ops = {
         .family =               AF_INET,
@@ -1088,7 +1090,9 @@ static int slow_chain_length(const struct rtable *head)
         return length >> FRACT_BITS;
 }
 
-static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, const void *daddr)
+static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst,
+                                           struct sk_buff *skb,
+                                           const void *daddr)
 {
         struct net_device *dev = dst->dev;
         const __be32 *pkey = daddr;
@@ -1098,6 +1102,8 @@ static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, const vo
         rt = (const struct rtable *) dst;
         if (rt->rt_gateway)
                 pkey = (const __be32 *) &rt->rt_gateway;
+        else if (skb)
+                pkey = &ip_hdr(skb)->daddr;
 
         n = __ipv4_neigh_lookup(dev, *(__force u32 *)pkey);
         if (n)
@@ -1107,7 +1113,7 @@ static struct neighbour *ipv4_neigh_lookup(const struct dst_entry *dst, const vo
 
 static int rt_bind_neighbour(struct rtable *rt)
 {
-        struct neighbour *n = ipv4_neigh_lookup(&rt->dst, &rt->rt_gateway);
+        struct neighbour *n = ipv4_neigh_lookup(&rt->dst, NULL, &rt->rt_gateway);
         if (IS_ERR(n))
                 return PTR_ERR(n);
         dst_set_neighbour(&rt->dst, n);
@@ -1388,7 +1394,7 @@ static void check_peer_redir(struct dst_entry *dst, struct inet_peer *peer)
 
         rt->rt_gateway = peer->redirect_learned.a4;
 
-        n = ipv4_neigh_lookup(&rt->dst, &rt->rt_gateway);
+        n = ipv4_neigh_lookup(&rt->dst, NULL, &rt->rt_gateway);
         if (IS_ERR(n)) {
                 rt->rt_gateway = orig_gw;
                 return;
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index c518e4ec0cea..4b581c675bb2 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -120,21 +120,27 @@ static u32 *ipv6_cow_metrics(struct dst_entry *dst, unsigned long old)
         return p;
 }
 
-static inline const void *choose_neigh_daddr(struct rt6_info *rt, const void *daddr)
+static inline const void *choose_neigh_daddr(struct rt6_info *rt,
+                                             struct sk_buff *skb,
+                                             const void *daddr)
 {
         struct in6_addr *p = &rt->rt6i_gateway;
 
         if (!ipv6_addr_any(p))
                 return (const void *) p;
+        else if (skb)
+                return &ipv6_hdr(skb)->daddr;
         return daddr;
 }
 
-static struct neighbour *ip6_neigh_lookup(const struct dst_entry *dst, const void *daddr)
+static struct neighbour *ip6_neigh_lookup(const struct dst_entry *dst,
+                                          struct sk_buff *skb,
+                                          const void *daddr)
 {
         struct rt6_info *rt = (struct rt6_info *) dst;
         struct neighbour *n;
 
-        daddr = choose_neigh_daddr(rt, daddr);
+        daddr = choose_neigh_daddr(rt, skb, daddr);
         n = __ipv6_neigh_lookup(&nd_tbl, dst->dev, daddr);
         if (n)
                 return n;
@@ -1162,7 +1168,7 @@ struct dst_entry *icmp6_dst_alloc(struct net_device *dev,
         if (neigh)
                 neigh_hold(neigh);
         else {
-                neigh = ip6_neigh_lookup(&rt->dst, &fl6->daddr);
+                neigh = ip6_neigh_lookup(&rt->dst, NULL, &fl6->daddr);
                 if (IS_ERR(neigh)) {
                         in6_dev_put(idev);
                         dst_free(&rt->dst);
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index ccfbd328a69d..a28a3f972d5b 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -2404,9 +2404,11 @@ static unsigned int xfrm_mtu(const struct dst_entry *dst)
         return mtu ? : dst_mtu(dst->path);
 }
 
-static struct neighbour *xfrm_neigh_lookup(const struct dst_entry *dst, const void *daddr)
+static struct neighbour *xfrm_neigh_lookup(const struct dst_entry *dst,
+                                           struct sk_buff *skb,
+                                           const void *daddr)
 {
-        return dst_neigh_lookup(dst->path, daddr);
+        return dst->path->ops->neigh_lookup(dst, skb, daddr);
 }
 
 int xfrm_policy_register_afinfo(struct xfrm_policy_afinfo *afinfo)