From f610b74b14d74a069f61583131e689550fd5bab3 Mon Sep 17 00:00:00 2001
From: "David S. Miller" <davem@davemloft.net>
Date: Mon, 11 Jul 2011 01:37:28 -0700
Subject: [PATCH] ipv4: Use universal hash for ARP.
We need to make sure the multiplier is odd.
Signed-off-by: David S. Miller <davem@davemloft.net>
---
include/net/arp.h | 7 +++++++
net/core/neighbour.c | 1 +
net/ipv4/arp.c | 3 +--
3 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/include/net/arp.h b/include/net/arp.h
index 91f0568a04ef..723bde501c64 100644
--- a/include/net/arp.h
+++ b/include/net/arp.h
@@ -8,6 +8,13 @@
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 int arp_find(unsigned char *haddr, struct sk_buff *skb);
extern int arp_ioctl(struct net *net, unsigned int cmd, void __user *arg);
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 4d5fc9433fd9..50bd960983e0 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -334,6 +334,7 @@ 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;
return ret;
}
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 1b74d3b64371..4412b57f6ff6 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -97,7 +97,6 @@
#include <linux/init.h>
#include <linux/net.h>
#include <linux/rcupdate.h>
-#include <linux/jhash.h>
#include <linux/slab.h>
#ifdef CONFIG_SYSCTL
#include <linux/sysctl.h>
@@ -232,7 +231,7 @@ static u32 arp_hash(const void *pkey,
const struct net_device *dev,
__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)
--
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