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-rw-r--r--kernel/include/linux/netfilter/ip_set_jhash.h152
1 files changed, 58 insertions, 94 deletions
diff --git a/kernel/include/linux/netfilter/ip_set_jhash.h b/kernel/include/linux/netfilter/ip_set_jhash.h
index 90bfcc3..d5e0d6d 100644
--- a/kernel/include/linux/netfilter/ip_set_jhash.h
+++ b/kernel/include/linux/netfilter/ip_set_jhash.h
@@ -1,7 +1,6 @@
#ifndef _LINUX_JHASH_H
#define _LINUX_JHASH_H
-
-/* jhash.h: Jenkins hash support.
+/* jhash.c: Jenkins hash support.
*
* Copyright (C) 2006. Bob Jenkins (bob_jenkins@burtleburtle.net)
*
@@ -17,141 +16,106 @@
* 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 Jozsef Kadlecsik (kadlec@blackhole.kfki.hu)
+ * 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. Jozsef
+ * any bugs present are my fault. The generic jhash is left out intentionally.
+ * Jozsef
*/
-
-#define __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 ^= __rot(c, 4); c += b; \
- b -= a; b ^= __rot(a, 6); a += c; \
- c -= b; c ^= __rot(b, 8); b += a; \
- a -= c; a ^= __rot(c,16); c += b; \
- b -= a; b ^= __rot(a,19); a += c; \
- c -= b; c ^= __rot(b, 4); b += a; \
+#ifdef __KERNEL__
+#include <asm/byteorder.h>
+
+/* 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 -= __rot(b,14); \
- a ^= c; a -= __rot(c,11); \
- b ^= a; b -= __rot(a,25); \
- c ^= b; c -= __rot(b,16); \
- a ^= c; a -= __rot(c,4); \
- b ^= a; b -= __rot(a,14); \
- c ^= b; c -= __rot(b,24); \
+#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); \
}
-/* An arbitrary value */
-#define JHASH_RANDOM_PARAM 0xdeadbeef
-
-/* The most generic version, hashes an arbitrary sequence
- * of bytes. No alignment or length assumptions are made about
- * the input 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_RANDOM_PARAM + length + initval;
-
- /* all but the last block: affect some 32 bits of (a,b,c) */
- while (length > 12) {
- a += (k[0] + ((u32)k[1]<<8) + ((u32)k[2]<<16) + ((u32)k[3]<<24));
- b += (k[4] + ((u32)k[5]<<8) + ((u32)k[6]<<16) + ((u32)k[7]<<24));
- c += (k[8] + ((u32)k[9]<<8) + ((u32)k[10]<<16) + ((u32)k[11]<<24));
- __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 :
- break;
- }
-
- return c;
-}
+#define JHASH_INITVAL 0xdeadbeef
-/* A special optimized version that handles 1 or more of u32s.
- * The length parameter here is the number of u32s in the key.
+/* 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_RANDOM_PARAM + (length<<2) + initval;
+ a = b = c = JHASH_INITVAL + (length<<2) + initval;
- /* handle most of the key */
+ /* Handle most of the key */
while (length > 3) {
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) {
+
+ /* 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: /* case 0: nothing left to add */
+ __jhash_final(a,b,c);
+ case 0: /* Nothing left to add */
break;
}
return c;
}
-/* A special ultra-optimized versions that knows they are hashing exactly
- * 3, 2 or 1 word(s).
- */
+/* 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_RANDOM_PARAM + initval;
- b += JHASH_RANDOM_PARAM + initval;
- c += JHASH_RANDOM_PARAM + initval;
-
- __jhash_final(a, b, c);
+ 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(0, a, b, initval);
+ return jhash_3words(a, b, 0, initval);
}
static inline u32 jhash_1word(u32 a, u32 initval)
{
- return jhash_3words(0, 0, a, initval);
+ return jhash_3words(a, 0, 0, initval);
}
+#endif /* __KERNEL__ */
+
#endif /* _LINUX_JHASH_H */