bind/lib/isc/siphash.c

/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * SPDX-License-Identifier: MPL-2.0
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
 *
 * See the COPYRIGHT file distributed with this work for additional
 * information regarding copyright ownership.
 */

#include <inttypes.h>
#include <string.h>
#include <unistd.h>

#include <isc/ascii.h>
#include <isc/endian.h>
#include <isc/siphash.h>
#include <isc/util.h>

/*
 * The implementation is based on SipHash reference C implementation by
 *
 * Copyright (c) 2012-2016 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/>.
 */

#define cROUNDS 2
#define dROUNDS 4

#define ROTATE64(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b))))

#define HALF_ROUND64(a, b, c, d, s, t) \
	a += b;                        \
	c += d;                        \
	b = ROTATE64(b, s) ^ a;        \
	d = ROTATE64(d, t) ^ c;        \
	a = ROTATE64(a, 32);

#define FULL_ROUND64(v0, v1, v2, v3)          \
	HALF_ROUND64(v0, v1, v2, v3, 13, 16); \
	HALF_ROUND64(v2, v1, v0, v3, 17, 21);

#define SIPROUND FULL_ROUND64

#define ROTATE32(x, b) (uint32_t)(((x) << (b)) | ((x) >> (32 - (b))))

#define HALF_ROUND32(a, b, c, d, s, t) \
	a += b;                        \
	c += d;                        \
	b = ROTATE32(b, s) ^ a;        \
	d = ROTATE32(d, t) ^ c;        \
	a = ROTATE32(a, 16);

#define FULL_ROUND32(v0, v1, v2, v3)        \
	HALF_ROUND32(v0, v1, v2, v3, 5, 8); \
	HALF_ROUND32(v2, v1, v0, v3, 13, 7);

#define HALFSIPROUND FULL_ROUND32

#define U8TO32_ONE(case_sensitive, byte) \
	(uint32_t)(case_sensitive ? byte : isc__ascii_tolower1(byte))

#define U8TO64_ONE(case_sensitive, byte) \
	(uint64_t)(case_sensitive ? byte : isc__ascii_tolower1(byte))

void
isc_siphash24(const uint8_t *k, const uint8_t *in, const size_t inlen,
	      bool case_sensitive, uint8_t *out) {
	REQUIRE(k != NULL);
	REQUIRE(out != NULL);
	REQUIRE(inlen == 0 || in != NULL);

	uint64_t k0 = ISC_U8TO64_LE(k);
	uint64_t k1 = ISC_U8TO64_LE(k + 8);

	uint64_t v0 = UINT64_C(0x736f6d6570736575) ^ k0;
	uint64_t v1 = UINT64_C(0x646f72616e646f6d) ^ k1;
	uint64_t v2 = UINT64_C(0x6c7967656e657261) ^ k0;
	uint64_t v3 = UINT64_C(0x7465646279746573) ^ k1;

	uint64_t b = ((uint64_t)inlen) << 56;

	if (in != NULL && inlen != 0) {
		const uint8_t *end = in + inlen - (inlen % sizeof(uint64_t));
		const size_t left = inlen & 7;

		for (; in != end; in += 8) {
			uint64_t m =
				case_sensitive
					? ISC_U8TO64_LE(in)
					: isc_ascii_tolower8(ISC_U8TO64_LE(in));

			v3 ^= m;

			for (size_t i = 0; i < cROUNDS; ++i) {
				SIPROUND(v0, v1, v2, v3);
			}

			v0 ^= m;
		}

		switch (left) {
		case 7:
			b |= U8TO64_ONE(case_sensitive, in[6]) << 48;
			FALLTHROUGH;
		case 6:
			b |= U8TO64_ONE(case_sensitive, in[5]) << 40;
			FALLTHROUGH;
		case 5:
			b |= U8TO64_ONE(case_sensitive, in[4]) << 32;
			FALLTHROUGH;
		case 4:
			b |= U8TO64_ONE(case_sensitive, in[3]) << 24;
			FALLTHROUGH;
		case 3:
			b |= U8TO64_ONE(case_sensitive, in[2]) << 16;
			FALLTHROUGH;
		case 2:
			b |= U8TO64_ONE(case_sensitive, in[1]) << 8;
			FALLTHROUGH;
		case 1:
			b |= U8TO64_ONE(case_sensitive, in[0]);
			FALLTHROUGH;
		case 0:
			break;
		default:
			UNREACHABLE();
		}
	}

	v3 ^= b;

	for (size_t i = 0; i < cROUNDS; ++i) {
		SIPROUND(v0, v1, v2, v3);
	}

	v0 ^= b;

	v2 ^= 0xff;

	for (size_t i = 0; i < dROUNDS; ++i) {
		SIPROUND(v0, v1, v2, v3);
	}

	b = v0 ^ v1 ^ v2 ^ v3;

	ISC_U64TO8_LE(out, b);
}

void
isc_halfsiphash24(const uint8_t *k, const uint8_t *in, const size_t inlen,
		  bool case_sensitive, uint8_t *out) {
	REQUIRE(k != NULL);
	REQUIRE(out != NULL);
	REQUIRE(inlen == 0 || in != NULL);

	uint32_t k0 = ISC_U8TO32_LE(k);
	uint32_t k1 = ISC_U8TO32_LE(k + 4);

	uint32_t v0 = UINT32_C(0x00000000) ^ k0;
	uint32_t v1 = UINT32_C(0x00000000) ^ k1;
	uint32_t v2 = UINT32_C(0x6c796765) ^ k0;
	uint32_t v3 = UINT32_C(0x74656462) ^ k1;

	uint32_t b = ((uint32_t)inlen) << 24;

	if (in != NULL && inlen != 0) {
		const uint8_t *end = in + inlen - (inlen % sizeof(uint32_t));
		const int left = inlen & 3;

		for (; in != end; in += 4) {
			uint32_t m =
				case_sensitive
					? ISC_U8TO32_LE(in)
					: isc_ascii_tolower4(ISC_U8TO32_LE(in));

			v3 ^= m;

			for (size_t i = 0; i < cROUNDS; ++i) {
				HALFSIPROUND(v0, v1, v2, v3);
			}

			v0 ^= m;
		}

		switch (left) {
		case 3:
			b |= U8TO32_ONE(case_sensitive, in[2]) << 16;
			FALLTHROUGH;
		case 2:
			b |= U8TO32_ONE(case_sensitive, in[1]) << 8;
			FALLTHROUGH;
		case 1:
			b |= U8TO32_ONE(case_sensitive, in[0]);
			FALLTHROUGH;
		case 0:
			break;
		default:
			UNREACHABLE();
		}
	}

	v3 ^= b;

	for (size_t i = 0; i < cROUNDS; ++i) {
		HALFSIPROUND(v0, v1, v2, v3);
	}

	v0 ^= b;

	v2 ^= 0xff;

	for (size_t i = 0; i < dROUNDS; ++i) {
		HALFSIPROUND(v0, v1, v2, v3);
	}

	b = v1 ^ v3;
	ISC_U32TO8_LE(out, b);
}