diff --git a/src/siphash24.c b/src/siphash24.c
new file mode 100644
index 0000000..5550e57
--- /dev/null
+++ b/src/siphash24.c
@@ -0,0 +1,159 @@
+/*
+   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>
+   Copyright (c) 2016 Maximilian Muenchow <maximilian.muenchow@teamspeak.com>
+   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 <linux/kernel.h>
+
+
+/* default: SipHash-2-4 */
+#define cROUNDS 2
+#define dROUNDS 4
+
+#define ROTL(x, b) (u64)(((x) << (b)) | ((x) >> (64 - (b))))
+
+#define U32TO8_LE(p, v)                                                        \
+  (p)[0] = (u8)((v));                                                          \
+  (p)[1] = (u8)((v) >> 8);                                                     \
+  (p)[2] = (u8)((v) >> 16);                                                    \
+  (p)[3] = (u8)((v) >> 24);
+
+#define U64TO8_LE(p, v)                                                        \
+  U32TO8_LE((p), (u32)((v)));                                                  \
+  U32TO8_LE((p) + 4, (u32)((v) >> 32));
+
+#define U8TO64_LE(p)                                                           \
+  (((u64)((p)[0])) | ((u64)((p)[1]) << 8) |                                    \
+   ((u64)((p)[2]) << 16) | ((u64)((p)[3]) << 24) |                             \
+   ((u64)((p)[4]) << 32) | ((u64)((p)[5]) << 40) |                             \
+   ((u64)((p)[6]) << 48) | ((u64)((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 {                                                                         \
+    printk("(%d) v0 %x %x\n", (int)inlen, (u32)(v0 >> 32), (u32)v0);           \
+    printk("(%d) v1 %x %x\n", (int)inlen, (u32)(v1 >> 32), (u32)v1);           \
+    printk("(%d) v2 %x %x\n", (int)inlen, (u32)(v2 >> 32), (u32)v2);           \
+    printk("(%d) v3 %x %x\n", (int)inlen, (u32)(v3 >> 32), (u32)v3);           \
+  } while (0)
+#else
+#define TRACE
+#endif
+
+int siphash(u8 *out, const u8 *in, u64 inlen, const u8 *k) {
+  /* "somepseudorandomlygeneratedbytes" */
+  u64 v0 = 0x736f6d6570736575ULL;
+  u64 v1 = 0x646f72616e646f6dULL;
+  u64 v2 = 0x6c7967656e657261ULL;
+  u64 v3 = 0x7465646279746573ULL;
+  u64 b;
+  u64 k0 = cpu_to_le64(U8TO64_LE(k));
+  u64 k1 = cpu_to_le64(U8TO64_LE(k + 8));
+  u64 m;
+  int i;
+  const u8 *end = in + inlen - (inlen % sizeof(u64));
+  const int left = inlen & 7;
+  b = ((u64)inlen) << 56;
+  v3 ^= k1;
+  v2 ^= k0;
+  v1 ^= k1;
+  v0 ^= k0;
+
+#ifdef DOUBLE
+  v1 ^= 0xee;
+#endif
+
+  for (; in != end; in += 8) {
+    m = cpu_to_le64(U8TO64_LE(in));
+    v3 ^= m;
+
+    TRACE;
+    for (i = 0; i < cROUNDS; ++i)
+      SIPROUND;
+
+    v0 ^= m;
+  }
+
+  switch (left) {
+  case 7:
+    b |= ((u64)in[6]) << 48;
+  case 6:
+    b |= ((u64)in[5]) << 40;
+  case 5:
+    b |= ((u64)in[4]) << 32;
+  case 4:
+    b |= ((u64)in[3]) << 24;
+  case 3:
+    b |= ((u64)in[2]) << 16;
+  case 2:
+    b |= ((u64)in[1]) << 8;
+  case 1:
+    b |= ((u64)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, cpu_to_le64(b));
+
+#ifdef DOUBLE
+  v1 ^= 0xdd;
+
+  TRACE;
+  for (i = 0; i < dROUNDS; ++i)
+    SIPROUND;
+
+  b = v0 ^ v1 ^ v2 ^ v3;
+  U64TO8_LE(out + 8, cpu_to_le64(b));
+#endif
+
+  return 0;
+}
+
diff --git a/src/xt_ts3init.c b/src/xt_ts3init.c
index 31bbd6a..0b954d1 100644
--- a/src/xt_ts3init.c
+++ b/src/xt_ts3init.c
@@ -14,6 +14,7 @@
  *    or 3 of the License, as published by the Free Software Foundation.
  */
 
+#include "siphash24.c"
 #include "ts3init_cookie.c"
 #include "ts3init_match.c"