ipv6: Use universal hash for NDISC.

In order to perform a proper universal hash on a vector of integers,
we have to use different universal hashes on each vector element.

Which means we need 4 different hash randoms for ipv6.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 0 deletions

diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index c977c377c015..e9c30023b784 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -79,6 +79,15 @@ struct nd_opt_hdr {
 	__u8		nd_opt_len;
 } __packed;
 
+static inline u32 ndisc_hashfn(const void *pkey, const struct net_device *dev, __u32 *hash_rnd)
+{
+	const u32 *p32 = pkey;
+
+	return (((p32[0] ^ dev->ifindex) * hash_rnd[0]) +
+		(p32[1] * hash_rnd[1]) +
+		(p32[2] * hash_rnd[2]) +
+		(p32[3] * hash_rnd[3]));
+}
 
 extern int			ndisc_init(void);