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authorDavid S. Miller <davem@davemloft.net>2011-12-29 00:06:58 +0400
committerDavid S. Miller <davem@davemloft.net>2011-12-29 00:06:58 +0400
commit2c2aba6c561ac425602f4a0be61422224cb87151 (patch)
tree30b5f2c40b823ca61e2e0930d5e98a89a83222bb /include
parent32288eb4d940b10e40c6d4178fe3a40d1437d2f8 (diff)
downloadlinux-2c2aba6c561ac425602f4a0be61422224cb87151.tar.xz
ipv6: Use universal hash for NDISC.
In order to perform a proper universal hash on a vector of integers, we have to use different universal hashes on each vector element. Which means we need 4 different hash randoms for ipv6. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
-rw-r--r--include/net/arp.h2
-rw-r--r--include/net/ndisc.h9
-rw-r--r--include/net/neighbour.h6
3 files changed, 14 insertions, 3 deletions
diff --git a/include/net/arp.h b/include/net/arp.h
index 4979af8b1559..0013dc87940b 100644
--- a/include/net/arp.h
+++ b/include/net/arp.h
@@ -23,7 +23,7 @@ static inline struct neighbour *__ipv4_neigh_lookup(struct neigh_table *tbl, str
rcu_read_lock_bh();
nht = rcu_dereference_bh(tbl->nht);
- hash_val = arp_hashfn(key, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
+ 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)) {
diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index c977c377c015..e9c30023b784 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -79,6 +79,15 @@ struct nd_opt_hdr {
__u8 nd_opt_len;
} __packed;
+static inline u32 ndisc_hashfn(const void *pkey, const struct net_device *dev, __u32 *hash_rnd)
+{
+ const u32 *p32 = pkey;
+
+ return (((p32[0] ^ dev->ifindex) * hash_rnd[0]) +
+ (p32[1] * hash_rnd[1]) +
+ (p32[2] * hash_rnd[2]) +
+ (p32[3] * hash_rnd[3]));
+}
extern int ndisc_init(void);
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index e31f0a86f9b7..34c996f46181 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -139,10 +139,12 @@ struct pneigh_entry {
* neighbour table manipulation
*/
+#define NEIGH_NUM_HASH_RND 4
+
struct neigh_hash_table {
struct neighbour __rcu **hash_buckets;
unsigned int hash_shift;
- __u32 hash_rnd;
+ __u32 hash_rnd[NEIGH_NUM_HASH_RND];
struct rcu_head rcu;
};
@@ -154,7 +156,7 @@ struct neigh_table {
int key_len;
__u32 (*hash)(const void *pkey,
const struct net_device *dev,
- __u32 hash_rnd);
+ __u32 *hash_rnd);
int (*constructor)(struct neighbour *);
int (*pconstructor)(struct pneigh_entry *);
void (*pdestructor)(struct pneigh_entry *);