From 4902415c1e95003068343d69206887be0e202615 Mon Sep 17 00:00:00 2001 From: Jozsef Kadlecsik Date: Tue, 7 Dec 2010 17:46:40 +0100 Subject: Create include/linux/netfilter/ipset/ directory Separate the ipset header files from netfilter header files. --- .../include/linux/netfilter/ipset/ip_set_jhash.h | 121 +++++++++++++++++++++ 1 file changed, 121 insertions(+) create mode 100644 kernel/include/linux/netfilter/ipset/ip_set_jhash.h (limited to 'kernel/include/linux/netfilter/ipset/ip_set_jhash.h') diff --git a/kernel/include/linux/netfilter/ipset/ip_set_jhash.h b/kernel/include/linux/netfilter/ipset/ip_set_jhash.h new file mode 100644 index 0000000..d5e0d6d --- /dev/null +++ b/kernel/include/linux/netfilter/ipset/ip_set_jhash.h @@ -0,0 +1,121 @@ +#ifndef _LINUX_JHASH_H +#define _LINUX_JHASH_H +/* jhash.c: Jenkins hash support. + * + * Copyright (C) 2006. Bob Jenkins (bob_jenkins@burtleburtle.net) + * + * http://burtleburtle.net/bob/hash/ + * + * These are the credits from Bob's sources: + * + * 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 + * 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. + * Jozsef + */ +#ifdef __KERNEL__ +#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) \ +{ \ + 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; \ +} + +/* __jhash_final - final mixing of 3 32-bit values (a,b,c) into 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); \ +} + +#define JHASH_INITVAL 0xdeadbeef + +/* 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 + * @initval: the previous hash, or an arbitray value + * + * Returns the hash value of the key. + */ +static inline u32 jhash2(const u32 *k, u32 length, u32 initval) +{ + u32 a, b, c; + + /* Set up the internal state */ + a = b = c = JHASH_INITVAL + (length<<2) + initval; + + /* Handle most of the key */ + while (length > 3) { + a += k[0]; + b += k[1]; + c += k[2]; + __jhash_mix(a,b,c); + length -= 3; + k += 3; + } + + /* Handle the last 3 u32's: all the case statements fall through */ + switch(length) { + case 3: c += k[2]; + case 2: b += k[1]; + case 1: a += k[0]; + __jhash_final(a,b,c); + case 0: /* Nothing left to add */ + break; + } + + return c; +} + +/* jhash_3words - hash exactly 3, 2 or 1 word(s) */ +static inline u32 jhash_3words(u32 a, u32 b, u32 c, u32 initval) +{ + a += JHASH_INITVAL; + b += JHASH_INITVAL; + c += initval; + + __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); +} + +static inline u32 jhash_1word(u32 a, u32 initval) +{ + return jhash_3words(a, 0, 0, initval); +} + +#endif /* __KERNEL__ */ + +#endif /* _LINUX_JHASH_H */ -- cgit v1.2.3