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authorDavid S. Miller <davem@davemloft.net>2011-12-28 21:06:58 +0100
committerDavid S. Miller <davem@davemloft.net>2011-12-28 21:06:58 +0100
commit2c2aba6c561ac425602f4a0be61422224cb87151 (patch)
tree30b5f2c40b823ca61e2e0930d5e98a89a83222bb
parentnetrom: avoid overflows in nr_setsockopt() (diff)
downloadlinux-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>
-rw-r--r--include/net/arp.h2
-rw-r--r--include/net/ndisc.h9
-rw-r--r--include/net/neighbour.h6
-rw-r--r--net/core/neighbour.c13
-rw-r--r--net/decnet/dn_neigh.c4
-rw-r--r--net/ipv4/arp.c6
-rw-r--r--net/ipv6/ndisc.c13
7 files changed, 32 insertions, 21 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 *);
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 4af151e1bf5d..e287346e0934 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -322,11 +322,18 @@ out_entries:
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 @@ static struct neigh_hash_table *neigh_hash_alloc(unsigned int shift)
}
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 @@ static int neightbl_fill_info(struct sk_buff *skb, struct neigh_table *tbl,
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 7d2fff29380f..befe426491ba 100644
--- a/net/decnet/dn_neigh.c
+++ b/net/decnet/dn_neigh.c
@@ -88,9 +88,9 @@ static const struct neigh_ops dn_phase3_ops = {
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 381a0876c363..59402be133f0 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 @@ int arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir)
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 f3e50c29add4..538a61960a24 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 @@ EXPORT_SYMBOL(ndisc_mc_map);
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)