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ipv4: Use universal hash for ARP.

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We need to make sure the multiplier is odd.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2011-07-11 01:37:28 -07:00
parent cd0893369c
commit f610b74b14
3 changed files with 9 additions and 2 deletions
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7
include/net/arp.h
View file

@ -8,6 +8,13 @@
extern struct neigh_table arp_tbl; extern struct neigh_table arp_tbl;
static inline u32 arp_hashfn(u32 key, const struct net_device *dev, u32 hash_rnd)
{
u32 val = key ^ dev->ifindex;
return val * hash_rnd;
}
extern void arp_init(void); extern void arp_init(void);
extern int arp_find(unsigned char *haddr, struct sk_buff *skb); extern int arp_find(unsigned char *haddr, struct sk_buff *skb);
extern int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg); extern int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg);

1
net/core/neighbour.c
View file

@ -334,6 +334,7 @@ static struct neigh_hash_table *neigh_hash_alloc(unsigned int shift)
ret->hash_buckets = buckets; ret->hash_buckets = buckets;
ret->hash_shift = shift; ret->hash_shift = shift;
get_random_bytes(&ret->hash_rnd, sizeof(ret->hash_rnd)); get_random_bytes(&ret->hash_rnd, sizeof(ret->hash_rnd));
ret->hash_rnd |= 1;
return ret; return ret;
} }

3
net/ipv4/arp.c
View file

@ -97,7 +97,6 @@
#include <linux/init.h> #include <linux/init.h>
#include <linux/net.h> #include <linux/net.h>
#include <linux/rcupdate.h> #include <linux/rcupdate.h>
#include <linux/jhash.h>
#include <linux/slab.h> #include <linux/slab.h>
#ifdef CONFIG_SYSCTL #ifdef CONFIG_SYSCTL
#include <linux/sysctl.h> #include <linux/sysctl.h>
@ -232,7 +231,7 @@ static u32 arp_hash(const void *pkey,
const struct net_device *dev, const struct net_device *dev,
__u32 hash_rnd) __u32 hash_rnd)
{ {
return jhash_2words(*(u32 *)pkey, dev->ifindex, hash_rnd); return arp_hashfn(*(u32 *)pkey, dev, hash_rnd);
} }
static int arp_constructor(struct neighbour *neigh) static int arp_constructor(struct neighbour *neigh)