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>
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 4af151e..e287346 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -322,11 +322,18 @@
goto out;
}
+static void neigh_get_hash_rnd(u32 *x)
+{
+ get_random_bytes(x, sizeof(*x));
+ *x |= 1;
+}
+
static struct neigh_hash_table *neigh_hash_alloc(unsigned int shift)
{
size_t size = (1 << shift) * sizeof(struct neighbour *);
struct neigh_hash_table *ret;
struct neighbour __rcu **buckets;
+ int i;
ret = kmalloc(sizeof(*ret), GFP_ATOMIC);
if (!ret)
@@ -343,8 +350,8 @@
}
ret->hash_buckets = buckets;
ret->hash_shift = shift;
- get_random_bytes(&ret->hash_rnd, sizeof(ret->hash_rnd));
- ret->hash_rnd |= 1;
+ for (i = 0; i < NEIGH_NUM_HASH_RND; i++)
+ neigh_get_hash_rnd(&ret->hash_rnd[i]);
return ret;
}
@@ -1828,7 +1835,7 @@
rcu_read_lock_bh();
nht = rcu_dereference_bh(tbl->nht);
- ndc.ndtc_hash_rnd = nht->hash_rnd;
+ ndc.ndtc_hash_rnd = nht->hash_rnd[0];
ndc.ndtc_hash_mask = ((1 << nht->hash_shift) - 1);
rcu_read_unlock_bh();
diff --git a/net/decnet/dn_neigh.c b/net/decnet/dn_neigh.c
index 7d2fff2..befe426 100644
--- a/net/decnet/dn_neigh.c
+++ b/net/decnet/dn_neigh.c
@@ -88,9 +88,9 @@
static u32 dn_neigh_hash(const void *pkey,
const struct net_device *dev,
- __u32 hash_rnd)
+ __u32 *hash_rnd)
{
- return jhash_2words(*(__u16 *)pkey, 0, hash_rnd);
+ return jhash_2words(*(__u16 *)pkey, 0, hash_rnd[0]);
}
struct neigh_table dn_neigh_table = {
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 381a087..59402be 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -121,7 +121,7 @@
/*
* Interface to generic neighbour cache.
*/
-static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 rnd);
+static u32 arp_hash(const void *pkey, const struct net_device *dev, __u32 *hash_rnd);
static int arp_constructor(struct neighbour *neigh);
static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb);
static void arp_error_report(struct neighbour *neigh, struct sk_buff *skb);
@@ -215,9 +215,9 @@
static u32 arp_hash(const void *pkey,
const struct net_device *dev,
- __u32 hash_rnd)
+ __u32 *hash_rnd)
{
- return arp_hashfn(*(u32 *)pkey, dev, hash_rnd);
+ return arp_hashfn(*(u32 *)pkey, dev, *hash_rnd);
}
static int arp_constructor(struct neighbour *neigh)
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index f3e50c2..538a619 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -93,7 +93,7 @@
static u32 ndisc_hash(const void *pkey,
const struct net_device *dev,
- __u32 rnd);
+ __u32 *hash_rnd);
static int ndisc_constructor(struct neighbour *neigh);
static void ndisc_solicit(struct neighbour *neigh, struct sk_buff *skb);
static void ndisc_error_report(struct neighbour *neigh, struct sk_buff *skb);
@@ -349,16 +349,9 @@
static u32 ndisc_hash(const void *pkey,
const struct net_device *dev,
- __u32 hash_rnd)
+ __u32 *hash_rnd)
{
- const u32 *p32 = pkey;
- u32 addr_hash, i;
-
- addr_hash = 0;
- for (i = 0; i < (sizeof(struct in6_addr) / sizeof(u32)); i++)
- addr_hash ^= *p32++;
-
- return jhash_2words(addr_hash, dev->ifindex, hash_rnd);
+ return ndisc_hashfn(pkey, dev, hash_rnd);
}
static int ndisc_constructor(struct neighbour *neigh)