Merge branch 'neigh-mpls-prep'

Eric W. Biederman says:

====================
Neighbour table prep for MPLS

In preparation for using the IPv4 and IPv6 neighbour tables in my mpls
code this patchset factors out ___neigh_lookup_noref from
__ipv4_neigh_lookup_noref, __ipv6_lookup_noref and neigh_lookup.
Allowing the lookup logic to be shared between the different
implementations.  At what appears to be no cost. (Aka the same assembly
is generated for ip6_finish_output2 and ip_finish_output2).

After that I add a simple function that takes an address family and an
address consults the neighbour table and sends the packet to the
appropriate location.  The address family argument decoupls callers
of neigh_xmit from the addresses families the packets are sent over.
(Aka The ipv6 module can be loaded after mpls and a previously
configured ipv6 next hop will start working).

The refactoring in ___neigh_lookup_noref may be a bit overkill but it
feels like the right thing to do.  Especially since the same code is
generated.
====================

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

3 files changed, 60 insertions, 33 deletions

diff --git a/include/net/arp.h b/include/net/arp.h
index 21ee1860abbc..5e0f891d476c 100644
--- a/include/net/arp.h
+++ b/include/net/arp.h
@@ -9,28 +9,17 @@
 
 extern struct neigh_table arp_tbl;
 
-static inline u32 arp_hashfn(u32 key, const struct net_device *dev, u32 hash_rnd)
+static inline u32 arp_hashfn(const void *pkey, const struct net_device *dev, u32 *hash_rnd)
 {
+	u32 key = *(const u32 *)pkey;
 	u32 val = key ^ hash32_ptr(dev);
 
-	return val * hash_rnd;
+	return val * hash_rnd[0];
 }
 
 static inline struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev, u32 key)
 {
-	struct neigh_hash_table *nht = rcu_dereference_bh(arp_tbl.nht);
-	struct neighbour *n;
-	u32 hash_val;
-
-	hash_val = arp_hashfn(key, dev, nht->hash_rnd[0]) >> (32 - nht->hash_shift);
-	for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
-	     n != NULL;
-	     n = rcu_dereference_bh(n->next)) {
-		if (n->dev == dev && *(u32 *)n->primary_key == key)
-			return n;
-	}
-
-	return NULL;
+	return ___neigh_lookup_noref(&arp_tbl, neigh_key_eq32, arp_hashfn, &key, dev);
 }
 
 static inline struct neighbour *__ipv4_neigh_lookup(struct net_device *dev, u32 key)
diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index 6bbda34d5e59..b3a7751251b4 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -156,24 +156,7 @@ static inline u32 ndisc_hashfn(const void *pkey, const struct net_device *dev, _
 
 static inline struct neighbour *__ipv6_neigh_lookup_noref(struct net_device *dev, const void *pkey)
 {
-	struct neigh_hash_table *nht;
-	const u32 *p32 = pkey;
-	struct neighbour *n;
-	u32 hash_val;
-
-	nht = rcu_dereference_bh(nd_tbl.nht);
-	hash_val = ndisc_hashfn(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
-	for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
-	     n != NULL;
-	     n = rcu_dereference_bh(n->next)) {
-		u32 *n32 = (u32 *) n->primary_key;
-		if (n->dev == dev &&
-		    ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
-		     (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0)
-			return n;
-	}
-
-	return NULL;
+	return ___neigh_lookup_noref(&nd_tbl, neigh_key_eq128, ndisc_hashfn, pkey, dev);
 }
 
 static inline struct neighbour *__ipv6_neigh_lookup(struct net_device *dev, const void *pkey)
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 9f912e4d4232..afb8237b0a8c 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -197,6 +197,7 @@ struct neigh_table {
 	__u32			(*hash)(const void *pkey,
 					const struct net_device *dev,
 					__u32 *hash_rnd);
+	bool			(*key_eq)(const struct neighbour *, const void *pkey);
 	int			(*constructor)(struct neighbour *);
 	int			(*pconstructor)(struct pneigh_entry *);
 	void			(*pdestructor)(struct pneigh_entry *);
@@ -247,6 +248,57 @@ static inline void *neighbour_priv(const struct neighbour *n)
 #define NEIGH_UPDATE_F_ISROUTER			0x40000000
 #define NEIGH_UPDATE_F_ADMIN			0x80000000
 
+
+static inline bool neigh_key_eq16(const struct neighbour *n, const void *pkey)
+{
+	return *(const u16 *)n->primary_key == *(const u16 *)pkey;
+}
+
+static inline bool neigh_key_eq32(const struct neighbour *n, const void *pkey)
+{
+	return *(const u32 *)n->primary_key == *(const u32 *)pkey;
+}
+
+static inline bool neigh_key_eq128(const struct neighbour *n, const void *pkey)
+{
+	const u32 *n32 = (const u32 *)n->primary_key;
+	const u32 *p32 = pkey;
+
+	return ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
+		(n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0;
+}
+
+static inline struct neighbour *___neigh_lookup_noref(
+	struct neigh_table *tbl,
+	bool (*key_eq)(const struct neighbour *n, const void *pkey),
+	__u32 (*hash)(const void *pkey,
+		      const struct net_device *dev,
+		      __u32 *hash_rnd),
+	const void *pkey,
+	struct net_device *dev)
+{
+	struct neigh_hash_table *nht = rcu_dereference_bh(tbl->nht);
+	struct neighbour *n;
+	u32 hash_val;
+
+	hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
+	for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
+	     n != NULL;
+	     n = rcu_dereference_bh(n->next)) {
+		if (n->dev == dev && key_eq(n, pkey))
+			return n;
+	}
+
+	return NULL;
+}
+
+static inline struct neighbour *__neigh_lookup_noref(struct neigh_table *tbl,
+						     const void *pkey,
+						     struct net_device *dev)
+{
+	return ___neigh_lookup_noref(tbl, tbl->key_eq, tbl->hash, pkey, dev);
+}
+
 void neigh_table_init(int index, struct neigh_table *tbl);
 int neigh_table_clear(int index, struct neigh_table *tbl);
 struct neighbour *neigh_lookup(struct neigh_table *tbl, const void *pkey,
@@ -306,6 +358,7 @@ void neigh_for_each(struct neigh_table *tbl,
 		    void (*cb)(struct neighbour *, void *), void *cookie);
 void __neigh_for_each_release(struct neigh_table *tbl,
 			      int (*cb)(struct neighbour *));
+int neigh_xmit(int fam, struct net_device *, const void *, struct sk_buff *);
 void pneigh_for_each(struct neigh_table *tbl,
 		     void (*cb)(struct pneigh_entry *));
 
@@ -459,4 +512,6 @@ static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
 		memcpy(dst, n->ha, dev->addr_len);
 	} while (read_seqretry(&n->ha_lock, seq));
 }
+
+
 #endif