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authorEric Dumazet <edumazet@google.com>2012-07-18 08:11:12 +0000
committerDavid S. Miller <davem@davemloft.net>2012-07-18 11:28:46 -0700
commitddbe503203855939946430e39bae58de11b70b69 (patch)
tree1605a8d3b14a92819eb8ed47ae5a84c1b66e12f8 /include/net/ipv6.h
parentdc9059512c09d09b99de6cd3a8bc842507934cbb (diff)
downloadop-kernel-dev-ddbe503203855939946430e39bae58de11b70b69.zip
op-kernel-dev-ddbe503203855939946430e39bae58de11b70b69.tar.gz
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 <edumazet@google.com> Reported-by: Andrew McGregor <andrewmcgr@gmail.com> Cc: Dave Taht <dave.taht@gmail.com> Cc: Tom Herbert <therbert@google.com> Cc: David Laight <David.Laight@ACULAB.COM> Cc: Joe Perches <joe@perches.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/ipv6.h')
-rw-r--r--include/net/ipv6.h13
1 files changed, 13 insertions, 0 deletions
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index f695f39..01c34b3 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] |
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