From: Matt Corallo <git@bluematt.me>
Date: Sat, 29 May 2021 23:01:01 +0000 (+0000)
Subject: Check in siphash
X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=commitdiff_plain;h=e7e5b2c8192b715dcfb574051c8d098c8360d746;p=flowspec-xdp

Check in siphash
---

diff --git a/siphash.h b/siphash.h
new file mode 100644
index 0000000..4c2ec7a
--- /dev/null
+++ b/siphash.h
@@ -0,0 +1,142 @@
+/*
+   SipHash reference C implementation
+
+   Copyright (c) 2012-2021 Jean-Philippe Aumasson
+   <jeanphilippe.aumasson@gmail.com>
+   Copyright (c) 2012-2014 Daniel J. Bernstein <djb@cr.yp.to>
+   Slightly tweaked by the git author.
+
+   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 <stddef.h>
+#include <stdint.h>
+
+/* default: SipHash-2-4 */
+#ifndef cROUNDS
+#define cROUNDS 1
+#endif
+#ifndef dROUNDS
+#define dROUNDS 3
+#endif
+
+#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 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
+#include <stdio.h>
+#define TRACE                                                                  \
+    do {                                                                       \
+        printf("(%3zu) v0 %016" PRIx64 "\n", inlen, v0);                       \
+        printf("(%3zu) v1 %016" PRIx64 "\n", inlen, v1);                       \
+        printf("(%3zu) v2 %016" PRIx64 "\n", inlen, v2);                       \
+        printf("(%3zu) v3 %016" PRIx64 "\n", inlen, v3);                       \
+    } while (0)
+#else
+#define TRACE
+#endif
+
+__attribute__((always_inline))
+static inline uint64_t siphash(const void *in, const size_t inlen, const uint8_t k[16]) {
+    const unsigned char *ni = (const unsigned char *)in;
+    const unsigned char *kk = (const unsigned char *)k;
+
+    uint64_t v0 = UINT64_C(0x736f6d6570736575);
+    uint64_t v1 = UINT64_C(0x646f72616e646f6d);
+    uint64_t v2 = UINT64_C(0x6c7967656e657261);
+    uint64_t v3 = UINT64_C(0x7465646279746573);
+    uint64_t k0 = U8TO64_LE(kk);
+    uint64_t k1 = U8TO64_LE(kk + 8);
+    uint64_t m;
+    int i;
+    const unsigned char *end = ni + inlen - (inlen % sizeof(uint64_t));
+    const int left = inlen & 7;
+    uint64_t b = ((uint64_t)inlen) << 56;
+    v3 ^= k1;
+    v2 ^= k0;
+    v1 ^= k1;
+    v0 ^= k0;
+
+    for (; ni != end; ni += 8) {
+        m = U8TO64_LE(ni);
+        v3 ^= m;
+
+        TRACE;
+        for (i = 0; i < cROUNDS; ++i)
+            SIPROUND;
+
+        v0 ^= m;
+    }
+
+    switch (left) {
+    case 7:
+        b |= ((uint64_t)ni[6]) << 48;
+    case 6:
+        b |= ((uint64_t)ni[5]) << 40;
+    case 5:
+        b |= ((uint64_t)ni[4]) << 32;
+    case 4:
+        b |= ((uint64_t)ni[3]) << 24;
+    case 3:
+        b |= ((uint64_t)ni[2]) << 16;
+    case 2:
+        b |= ((uint64_t)ni[1]) << 8;
+    case 1:
+        b |= ((uint64_t)ni[0]);
+        break;
+    case 0:
+        break;
+    }
+
+    v3 ^= b;
+
+    TRACE;
+    for (i = 0; i < cROUNDS; ++i)
+        SIPROUND;
+
+    v0 ^= b;
+    v2 ^= 0xff;
+
+    TRACE;
+    for (i = 0; i < dROUNDS; ++i)
+        SIPROUND;
+
+    b = v0 ^ v1 ^ v2 ^ v3;
+    return b;
+}
diff --git a/xdp.c b/xdp.c
index de4d86e..1344acd 100644
--- a/xdp.c
+++ b/xdp.c
@@ -7,7 +7,7 @@
 #include <linux/icmpv6.h>
 #include <arpa/inet.h>
 
-#define NULL (void*)0
+#include "siphash.h"
 
 /* IP flags. */
 #define IP_CE		0x8000		/* Flag: "Congestion"		*/