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ipv6: user better hash for addrconf

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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>
This commit is contained in:
stephen hemminger 2010-03-17 20:31:12 +00:00 • committed by David S. Miller
commit 3a88a81d89
1 changed files with 8 additions and 17 deletions
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25
net/ipv6/addrconf.c
View file

@ -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) {