From ad75e5387cb0b89f26e8950b8947b17293b82a43 Mon Sep 17 00:00:00 2001 From: Jozsef Kadlecsik Date: Wed, 8 Dec 2010 16:52:43 +0100 Subject: Update ip_set_jhash.h Update ip_set_jhash.h with the version which was submitted for kernel inclusion. --- .../include/linux/netfilter/ipset/ip_set_jhash.h | 114 +++++++++++++++------ 1 file changed, 81 insertions(+), 33 deletions(-) diff --git a/kernel/include/linux/netfilter/ipset/ip_set_jhash.h b/kernel/include/linux/netfilter/ipset/ip_set_jhash.h index d5e0d6d..72ca901 100644 --- a/kernel/include/linux/netfilter/ipset/ip_set_jhash.h +++ b/kernel/include/linux/netfilter/ipset/ip_set_jhash.h @@ -1,6 +1,7 @@ #ifndef _LINUX_JHASH_H #define _LINUX_JHASH_H -/* jhash.c: Jenkins hash support. + +/* jhash.h: Jenkins hash support. * * Copyright (C) 2006. Bob Jenkins (bob_jenkins@burtleburtle.net) * @@ -11,53 +12,101 @@ * lookup3.c, by Bob Jenkins, May 2006, Public Domain. * * These are functions for producing 32-bit hashes for hash table lookup. - * hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final() - * are externally useful functions. Routines to test the hash are included + * hashword(), hashlittle(), hashlittle2(), hashbig(), mix(), and final() + * are externally useful functions. Routines to test the hash are included * if SELF_TEST is defined. You can use this free for any purpose. It's in * the public domain. It has no warranty. * * Copyright (C) 2009-2010 Jozsef Kadlecsik (kadlec@blackhole.kfki.hu) * * I've modified Bob's hash to be useful in the Linux kernel, and - * any bugs present are my fault. The generic jhash is left out intentionally. + * any bugs present are my fault. * Jozsef */ -#ifdef __KERNEL__ -#include +#include +#include /* Best hash sizes are of power of two */ #define jhash_size(n) ((u32)1<<(n)) /* Mask the hash value, i.e (value & jhash_mask(n)) instead of (value % n) */ #define jhash_mask(n) (jhash_size(n)-1) -/* __jhash_rot - rotate 32 bit */ -#define __jhash_rot(x,k) (((x)<<(k)) | ((x)>>(32-(k)))) - /* __jhash_mix -- mix 3 32-bit values reversibly. */ -#define __jhash_mix(a,b,c) \ +#define __jhash_mix(a, b, c) \ { \ - a -= c; a ^= __jhash_rot(c, 4); c += b; \ - b -= a; b ^= __jhash_rot(a, 6); a += c; \ - c -= b; c ^= __jhash_rot(b, 8); b += a; \ - a -= c; a ^= __jhash_rot(c,16); c += b; \ - b -= a; b ^= __jhash_rot(a,19); a += c; \ - c -= b; c ^= __jhash_rot(b, 4); b += a; \ + a -= c; a ^= rol32(c, 4); c += b; \ + b -= a; b ^= rol32(a, 6); a += c; \ + c -= b; c ^= rol32(b, 8); b += a; \ + a -= c; a ^= rol32(c, 16); c += b; \ + b -= a; b ^= rol32(a, 19); a += c; \ + c -= b; c ^= rol32(b, 4); b += a; \ } /* __jhash_final - final mixing of 3 32-bit values (a,b,c) into c */ -#define __jhash_final(a,b,c) \ +#define __jhash_final(a, b, c) \ { \ - c ^= b; c -= __jhash_rot(b,14); \ - a ^= c; a -= __jhash_rot(c,11); \ - b ^= a; b -= __jhash_rot(a,25); \ - c ^= b; c -= __jhash_rot(b,16); \ - a ^= c; a -= __jhash_rot(c,4); \ - b ^= a; b -= __jhash_rot(a,14); \ - c ^= b; c -= __jhash_rot(b,24); \ + c ^= b; c -= rol32(b, 14); \ + a ^= c; a -= rol32(c, 11); \ + b ^= a; b -= rol32(a, 25); \ + c ^= b; c -= rol32(b, 16); \ + a ^= c; a -= rol32(c, 4); \ + b ^= a; b -= rol32(a, 14); \ + c ^= b; c -= rol32(b, 24); \ } +/* An arbitrary initial parameter */ #define JHASH_INITVAL 0xdeadbeef +/* jhash - hash an arbitrary key + * @k: sequence of bytes as key + * @length: the length of the key + * @initval: the previous hash, or an arbitray value + * + * The generic version, hashes an arbitrary sequence of bytes. + * No alignment or length assumptions are made about the input key. + * + * Returns the hash value of the key. The result depends on endianness. + */ +static inline u32 jhash(const void *key, u32 length, u32 initval) +{ + u32 a, b, c; + const u8 *k = key; + + /* Set up the internal state */ + a = b = c = JHASH_INITVAL + length + initval; + + /* All but the last block: affect some 32 bits of (a,b,c) */ + while (length > 12) { + a += __get_unaligned_cpu32(k); + b += __get_unaligned_cpu32(k + 4); + c += __get_unaligned_cpu32(k + 8); + __jhash_mix(a, b, c); + length -= 12; + k += 12; + } + /* Last block: affect all 32 bits of (c) */ + /* All the case statements fall through */ + switch (length) { + case 12: c += (u32)k[11]<<24; + case 11: c += (u32)k[10]<<16; + case 10: c += (u32)k[9]<<8; + case 9: c += k[8]; + case 8: b += (u32)k[7]<<24; + case 7: b += (u32)k[6]<<16; + case 6: b += (u32)k[5]<<8; + case 5: b += k[4]; + case 4: a += (u32)k[3]<<24; + case 3: a += (u32)k[2]<<16; + case 2: a += (u32)k[1]<<8; + case 1: a += k[0]; + __jhash_final(a, b, c); + case 0: /* Nothing left to add */ + break; + } + + return c; +} + /* jhash2 - hash an array of u32's * @k: the key which must be an array of u32's * @length: the number of u32's in the key @@ -77,17 +126,17 @@ static inline u32 jhash2(const u32 *k, u32 length, u32 initval) a += k[0]; b += k[1]; c += k[2]; - __jhash_mix(a,b,c); + __jhash_mix(a, b, c); length -= 3; k += 3; } - + /* Handle the last 3 u32's: all the case statements fall through */ - switch(length) { + switch (length) { case 3: c += k[2]; case 2: b += k[1]; case 1: a += k[0]; - __jhash_final(a,b,c); + __jhash_final(a, b, c); case 0: /* Nothing left to add */ break; } @@ -102,10 +151,11 @@ static inline u32 jhash_3words(u32 a, u32 b, u32 c, u32 initval) b += JHASH_INITVAL; c += initval; - __jhash_final(a,b,c); - + __jhash_final(a, b, c); + return c; } + static inline u32 jhash_2words(u32 a, u32 b, u32 initval) { return jhash_3words(a, b, 0, initval); @@ -113,9 +163,7 @@ static inline u32 jhash_2words(u32 a, u32 b, u32 initval) static inline u32 jhash_1word(u32 a, u32 initval) { - return jhash_3words(a, 0, 0, initval); + return jhash_3words(a, 0, 0, initval); } -#endif /* __KERNEL__ */ - #endif /* _LINUX_JHASH_H */ -- cgit v1.2.3