neigh: Factor out ___neigh_lookup_noref
While looking at the mpls code I found myself writing yet another
version of neigh_lookup_noref. We currently have __ipv4_lookup_noref
and __ipv6_lookup_noref.
So to make my work a little easier and to make it a smidge easier to
verify/maintain the mpls code in the future I stopped and wrote
___neigh_lookup_noref. Then I rewote __ipv4_lookup_noref and
__ipv6_lookup_noref in terms of this new function. I tested my new
version by verifying that the same code is generated in
ip_finish_output2 and ip6_finish_output2 where these functions are
inlined.
To get to ___neigh_lookup_noref I added a new neighbour cache table
function key_eq. So that the static size of the key would be
available.
I also added __neigh_lookup_noref for people who want to to lookup
a neighbour table entry quickly but don't know which neibhgour table
they are going to look up.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 9f912e4..14e3f01 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -197,6 +197,7 @@
__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 @@
#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,