diff options
| author | David S. Miller <davem@davemloft.net> | 2011-12-28 21:06:58 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2011-12-28 21:06:58 +0100 |
| commit | 2c2aba6c561ac425602f4a0be61422224cb87151 (patch) | |
| tree | 30b5f2c40b823ca61e2e0930d5e98a89a83222bb /include/net | |
| parent | netrom: avoid overflows in nr_setsockopt() (diff) | |
| download | linux-2c2aba6c561ac425602f4a0be61422224cb87151.tar.xz linux-2c2aba6c561ac425602f4a0be61422224cb87151.zip | |
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/net')
| -rw-r--r-- | include/net/arp.h | 2 | ||||
| -rw-r--r-- | include/net/ndisc.h | 9 | ||||
| -rw-r--r-- | include/net/neighbour.h | 6 |
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 *); |