Add SipHash reference implementation

src/common/siphash24.c

+/*
+   SipHash reference C implementation
+
+   Copyright (c) 2012-2014 Jean-Philippe Aumasson
+   <jeanphilippe.aumasson@gmail.com>
+   Copyright (c) 2012-2014 Daniel J. Bernstein <djb@cr.yp.to>
+
+   To the extent possible under law, the author(s) have dedicated all copyright
+   and related and neighboring rights to this software to the public domain
+   worldwide. This software is distributed without any warranty.
+
+   You should have received a copy of the CC0 Public Domain Dedication along
+   with
+   this software. If not, see
+   <http://creativecommons.org/publicdomain/zero/1.0/>.
+ */
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+/* default: SipHash-2-4 */
+#define cROUNDS 2
+#define dROUNDS 4
+
+#define ROTL(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b))))
+
+#define U32TO8_LE(p, v)                                                        \
+  (p)[0] = (uint8_t)((v));                                                     \
+  (p)[1] = (uint8_t)((v) >> 8);                                                \
+  (p)[2] = (uint8_t)((v) >> 16);                                               \
+  (p)[3] = (uint8_t)((v) >> 24);
+
+#define U64TO8_LE(p, v)                                                        \
+  U32TO8_LE((p), (uint32_t)((v)));                                             \
+  U32TO8_LE((p) + 4, (uint32_t)((v) >> 32));
+
+#define U8TO64_LE(p)                                                           \
+  (((uint64_t)((p)[0])) | ((uint64_t)((p)[1]) << 8) |                          \
+   ((uint64_t)((p)[2]) << 16) | ((uint64_t)((p)[3]) << 24) |                   \
+   ((uint64_t)((p)[4]) << 32) | ((uint64_t)((p)[5]) << 40) |                   \
+   ((uint64_t)((p)[6]) << 48) | ((uint64_t)((p)[7]) << 56))
+
+#define SIPROUND                                                               \
+  do {                                                                         \
+    v0 += v1;                                                                  \
+    v1 = ROTL(v1, 13);                                                         \
+    v1 ^= v0;                                                                  \
+    v0 = ROTL(v0, 32);                                                         \
+    v2 += v3;                                                                  \
+    v3 = ROTL(v3, 16);                                                         \
+    v3 ^= v2;                                                                  \
+    v0 += v3;                                                                  \
+    v3 = ROTL(v3, 21);                                                         \
+    v3 ^= v0;                                                                  \
+    v2 += v1;                                                                  \
+    v1 = ROTL(v1, 17);                                                         \
+    v1 ^= v2;                                                                  \
+    v2 = ROTL(v2, 32);                                                         \
+  } while (0)
+
+#ifdef DEBUG
+#define TRACE                                                                  \
+  do {                                                                         \
+    printf("(%3d) v0 %08x %08x\n", (int)inlen, (uint32_t)(v0 >> 32),           \
+           (uint32_t)v0);                                                      \
+    printf("(%3d) v1 %08x %08x\n", (int)inlen, (uint32_t)(v1 >> 32),           \
+           (uint32_t)v1);                                                      \
+    printf("(%3d) v2 %08x %08x\n", (int)inlen, (uint32_t)(v2 >> 32),           \
+           (uint32_t)v2);                                                      \
+    printf("(%3d) v3 %08x %08x\n", (int)inlen, (uint32_t)(v3 >> 32),           \
+           (uint32_t)v3);                                                      \
+  } while (0)
+#else
+#define TRACE
+#endif
+
+int siphash(uint8_t *out, const uint8_t *in, uint64_t inlen, const uint8_t *k) {
+  /* "somepseudorandomlygeneratedbytes" */
+  uint64_t v0 = 0x736f6d6570736575ULL;
+  uint64_t v1 = 0x646f72616e646f6dULL;
+  uint64_t v2 = 0x6c7967656e657261ULL;
+  uint64_t v3 = 0x7465646279746573ULL;
+  uint64_t b;
+  uint64_t k0 = U8TO64_LE(k);
+  uint64_t k1 = U8TO64_LE(k + 8);
+  uint64_t m;
+  int i;
+  const uint8_t *end = in + inlen - (inlen % sizeof(uint64_t));
+  const int left = inlen & 7;
+  b = ((uint64_t)inlen) << 56;
+  v3 ^= k1;
+  v2 ^= k0;
+  v1 ^= k1;
+  v0 ^= k0;
+
+#ifdef DOUBLE
+  v1 ^= 0xee;
+#endif
+
+  for (; in != end; in += 8) {
+    m = U8TO64_LE(in);
+    v3 ^= m;
+
+    TRACE;
+    for (i = 0; i < cROUNDS; ++i)
+      SIPROUND;
+
+    v0 ^= m;
+  }
+
+  switch (left) {
+  case 7:
+    b |= ((uint64_t)in[6]) << 48;
+  case 6:
+    b |= ((uint64_t)in[5]) << 40;
+  case 5:
+    b |= ((uint64_t)in[4]) << 32;
+  case 4:
+    b |= ((uint64_t)in[3]) << 24;
+  case 3:
+    b |= ((uint64_t)in[2]) << 16;
+  case 2:
+    b |= ((uint64_t)in[1]) << 8;
+  case 1:
+    b |= ((uint64_t)in[0]);
+    break;
+  case 0:
+    break;
+  }
+
+  v3 ^= b;
+
+  TRACE;
+  for (i = 0; i < cROUNDS; ++i)
+    SIPROUND;
+
+  v0 ^= b;
+
+#ifndef DOUBLE
+  v2 ^= 0xff;
+#else
+  v2 ^= 0xee;
+#endif
+
+  TRACE;
+  for (i = 0; i < dROUNDS; ++i)
+    SIPROUND;
+
+  b = v0 ^ v1 ^ v2 ^ v3;
+  U64TO8_LE(out, b);
+
+#ifdef DOUBLE
+  v1 ^= 0xdd;
+
+  TRACE;
+  for (i = 0; i < dROUNDS; ++i)
+    SIPROUND;
+
+  b = v0 ^ v1 ^ v2 ^ v3;
+  U64TO8_LE(out + 8, b);
+#endif
+
+  return 0;
+}
+