Patchwork [1/2] netfilter: nfnetlink_queue: use xor hash function to distribute instances

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Submitter Pablo Neira
Date March 14, 2013, 4:03 p.m.
Message ID <1363276999-30144-1-git-send-email-pablo@netfilter.org>
Download mbox | patch
Permalink /patch/227726/
State Accepted
Headers show

Comments

Pablo Neira - March 14, 2013, 4:03 p.m.
From: Pablo Neira Ayuso <pablo@netfilter.org>

Thanks to Eric Dumazet for suggesting this during the NFWS.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nfnetlink_queue_core.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

diff --git a/net/netfilter/nfnetlink_queue_core.c b/net/netfilter/nfnetlink_queue_core.c
index 3158d87..4512658 100644
--- a/net/netfilter/nfnetlink_queue_core.c
+++ b/net/netfilter/nfnetlink_queue_core.c
@@ -73,7 +73,7 @@  static struct hlist_head instance_table[INSTANCE_BUCKETS] __read_mostly;
 
 static inline u_int8_t instance_hashfn(u_int16_t queue_num)
 {
-	return ((queue_num >> 8) | queue_num) % INSTANCE_BUCKETS;
+	return ((queue_num >> 8) ^ queue_num) % INSTANCE_BUCKETS;
 }
 
 static struct nfqnl_instance *