From ddbe503203855939946430e39bae58de11b70b69 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 18 Jul 2012 08:11:12 +0000 Subject: ipv6: add ipv6_addr_hash() helper Introduce ipv6_addr_hash() helper doing a XOR on all bits of an IPv6 address, with an optimized x86_64 version. Use it in flow dissector, as suggested by Andrew McGregor, to reduce hash collision probabilities in fq_codel (and other users of flow dissector) Use it in ip6_tunnel.c and use more bit shuffling, as suggested by David Laight, as existing hash was ignoring most of them. Use it in sunrpc and use more bit shuffling, using hash_32(). Use it in net/ipv6/addrconf.c, using hash_32() as well. As a cleanup, use it in net/ipv4/tcp_metrics.c Signed-off-by: Eric Dumazet Reported-by: Andrew McGregor Cc: Dave Taht Cc: Tom Herbert Cc: David Laight Cc: Joe Perches Signed-off-by: David S. Miller --- include/net/ipv6.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include/net/ipv6.h') diff --git a/include/net/ipv6.h b/include/net/ipv6.h index f695f39e8926..01c34b363a34 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -419,6 +419,19 @@ static inline bool ipv6_addr_any(const struct in6_addr *a) #endif } +static inline u32 ipv6_addr_hash(const struct in6_addr *a) +{ +#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64 + const unsigned long *ul = (const unsigned long *)a; + unsigned long x = ul[0] ^ ul[1]; + + return (u32)(x ^ (x >> 32)); +#else + return (__force u32)(a->s6_addr32[0] ^ a->s6_addr32[1] ^ + a->s6_addr32[2] ^ a->s6_addr32[3]); +#endif +} + static inline bool ipv6_addr_loopback(const struct in6_addr *a) { return (a->s6_addr32[0] | a->s6_addr32[1] | -- cgit v1.2.3