Importing all of DRL, including ulogd and all of its files.

[distributedratelimiting.git] / include / linux / jhash.h

diff --git a/include/linux/jhash.h b/include/linux/jhash.h
new file mode 100644 (file)
index 0000000..83f6af2
--- /dev/null
+++ b/include/linux/jhash.h
@@ -0,0 +1,143 @@
+#ifndef _LINUX_JHASH_H
+#define _LINUX_JHASH_H
+
+/* jhash.h: Jenkins hash support.
+ *
+ * Copyright (C) 1996 Bob Jenkins (bob_jenkins@burtleburtle.net)
+ *
+ * http://burtleburtle.net/bob/hash/
+ *
+ * These are the credits from Bob's sources:
+ *
+ * lookup2.c, by Bob Jenkins, December 1996, Public Domain.
+ * hash(), hash2(), hash3, and mix() 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 has no warranty.
+ *
+ * Copyright (C) 2003 David S. Miller (davem@redhat.com)
+ *
+ * I've modified Bob's hash to be useful in the Linux kernel, and
+ * any bugs present are surely my fault.  -DaveM
+ */
+
+/* NOTE: Arguments are modified. */
+#define __jhash_mix(a, b, c) \
+{ \
+  a -= b; a -= c; a ^= (c>>13); \
+  b -= c; b -= a; b ^= (a<<8); \
+  c -= a; c -= b; c ^= (b>>13); \
+  a -= b; a -= c; a ^= (c>>12);  \
+  b -= c; b -= a; b ^= (a<<16); \
+  c -= a; c -= b; c ^= (b>>5); \
+  a -= b; a -= c; a ^= (c>>3);  \
+  b -= c; b -= a; b ^= (a<<10); \
+  c -= a; c -= b; c ^= (b>>15); \
+}
+
+/* The golden ration: an arbitrary value */
+#define JHASH_GOLDEN_RATIO     0x9e3779b9
+
+/* The most generic version, hashes an arbitrary sequence
+ * of bytes.  No alignment or length assumptions are made about
+ * the input key.
+ */
+static inline u32 jhash(void *key, u32 length, u32 initval)
+{
+       u32 a, b, c, len;
+       u8 *k = key;
+
+       len = length;
+       a = b = JHASH_GOLDEN_RATIO;
+       c = initval;
+
+       while (len >= 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);
+
+               k += 12;
+               len -= 12;
+       }
+
+       c += length;
+       switch (len) {
+       case 11: c += ((u32)k[10]<<24);
+       case 10: c += ((u32)k[9]<<16);
+       case 9 : c += ((u32)k[8]<<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_mix(a,b,c);
+
+       return c;
+}
+
+/* A special optimized version that handles 1 or more of u32s.
+ * The length parameter here is the number of u32s in the key.
+ */
+static inline u32 jhash2(u32 *k, u32 length, u32 initval)
+{
+       u32 a, b, c, len;
+
+       a = b = JHASH_GOLDEN_RATIO;
+       c = initval;
+       len = length;
+
+       while (len >= 3) {
+               a += k[0];
+               b += k[1];
+               c += k[2];
+               __jhash_mix(a, b, c);
+               k += 3; len -= 3;
+       }
+
+       c += length * 4;
+
+       switch (len) {
+       case 2 : b += k[1];
+       case 1 : a += k[0];
+       };
+
+       __jhash_mix(a,b,c);
+
+       return c;
+}
+
+
+/* A special ultra-optimized versions that knows they are hashing exactly
+ * 3, 2 or 1 word(s).
+ *
+ * NOTE: In partilar the "c += length; __jhash_mix(a,b,c);" normally
+ *       done at the end is not done here.
+ */
+static inline u32 jhash_3words(u32 a, u32 b, u32 c, u32 initval)
+{
+       a += JHASH_GOLDEN_RATIO;
+       b += JHASH_GOLDEN_RATIO;
+       c += initval;
+
+       __jhash_mix(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 /* _LINUX_JHASH_H */