From 3a88a81d89c20be312b3b219b185bbdde24b8fb8 Mon Sep 17 00:00:00 2001
From: stephen hemminger <shemminger@vyatta.com>
Date: Wed, 17 Mar 2010 20:31:12 +0000
Subject: [PATCH] ipv6: user better hash for addrconf
The existing hash function has a couple of issues:
* it is hardwired to 16 for IN6_ADDR_HSIZE
* limited to 256 and callers using int
* use jhash2 rather than some old BSD algorithm
No need for random seed since this is local only (based on assigned
addresses) table.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv6/addrconf.c | 25 ++++++++-----------------
1 file changed, 8 insertions(+), 17 deletions(-)
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 7ffd5eeab967..1e5e41fe92bc 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -573,23 +573,14 @@ ipv6_link_dev_addr(struct inet6_dev *idev, struct inet6_ifaddr *ifp)
*ifap = ifp;
}
-/*
- * Hash function taken from net_alias.c
- */
-static u8 ipv6_addr_hash(const struct in6_addr *addr)
+static u32 ipv6_addr_hash(const struct in6_addr *addr)
{
- __u32 word;
-
/*
* We perform the hash function over the last 64 bits of the address
* This will include the IEEE address token on links that support it.
*/
-
- word = (__force u32)(addr->s6_addr32[2] ^ addr->s6_addr32[3]);
- word ^= (word >> 16);
- word ^= (word >> 8);
-
- return ((word ^ (word >> 4)) & 0x0f);
+ return jhash_2words(addr->s6_addr32[2], addr->s6_addr32[3], 0)
+ & (IN6_ADDR_HSIZE - 1);
}
/* On success it returns ifp with increased reference count */
@@ -600,7 +591,7 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr, int pfxlen,
{
struct inet6_ifaddr *ifa = NULL;
struct rt6_info *rt;
- int hash;
+ unsigned int hash;
int err = 0;
int addr_type = ipv6_addr_type(addr);
@@ -1277,7 +1268,7 @@ int ipv6_chk_addr(struct net *net, struct in6_addr *addr,
{
struct inet6_ifaddr *ifp = NULL;
struct hlist_node *node;
- u8 hash = ipv6_addr_hash(addr);
+ unsigned int hash = ipv6_addr_hash(addr);
rcu_read_lock_bh();
hlist_for_each_entry_rcu(ifp, node, &inet6_addr_lst[hash], addr_lst) {
@@ -1302,7 +1293,7 @@ int ipv6_chk_same_addr(struct net *net, const struct in6_addr *addr,
{
struct inet6_ifaddr *ifp;
struct hlist_node *node;
- u8 hash = ipv6_addr_hash(addr);
+ unsigned int hash = ipv6_addr_hash(addr);
hlist_for_each_entry(ifp, node, &inet6_addr_lst[hash], addr_lst) {
if (!net_eq(dev_net(ifp->idev->dev), net))
@@ -1345,7 +1336,7 @@ struct inet6_ifaddr *ipv6_get_ifaddr(struct net *net, const struct in6_addr *add
{
struct inet6_ifaddr *ifp = NULL;
struct hlist_node *node;
- u8 hash = ipv6_addr_hash(addr);
+ unsigned int hash = ipv6_addr_hash(addr);
rcu_read_lock_bh();
hlist_for_each_entry_rcu(ifp, node, &inet6_addr_lst[hash], addr_lst) {
@@ -3083,7 +3074,7 @@ int ipv6_chk_home_addr(struct net *net, struct in6_addr *addr)
int ret = 0;
struct inet6_ifaddr *ifp = NULL;
struct hlist_node *n;
- u8 hash = ipv6_addr_hash(addr);
+ unsigned int hash = ipv6_addr_hash(addr);
rcu_read_lock_bh();
hlist_for_each_entry_rcu(ifp, n, &inet6_addr_lst[hash], addr_lst) {
--
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