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      1 /*	$NetBSD: hash.c,v 1.10 2026/01/29 18:37:54 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
      5  *
      6  * SPDX-License-Identifier: MPL-2.0
      7  *
      8  * This Source Code Form is subject to the terms of the Mozilla Public
      9  * License, v. 2.0. If a copy of the MPL was not distributed with this
     10  * file, you can obtain one at https://mozilla.org/MPL/2.0/.
     11  *
     12  * See the COPYRIGHT file distributed with this work for additional
     13  * information regarding copyright ownership.
     14  */
     15 
     16 #include <inttypes.h>
     17 #include <stdbool.h>
     18 #include <stddef.h>
     19 
     20 #include <isc/ascii.h>
     21 #include <isc/hash.h> /* IWYU pragma: keep */
     22 #include <isc/random.h>
     23 #include <isc/result.h>
     24 #include <isc/siphash.h>
     25 #include <isc/string.h>
     26 #include <isc/types.h>
     27 #include <isc/util.h>
     28 
     29 static uint8_t isc_hash_key[16];
     30 
     31 void
     32 isc__hash_initialize(void) {
     33 	/*
     34 	 * Set a constant key to help in problem reproduction should
     35 	 * fuzzing find a crash or a hang.
     36 	 */
     37 	uint8_t key[16] = { 1 };
     38 #if !FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
     39 	isc_random_buf(key, sizeof(key));
     40 #endif /* if FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION */
     41 	STATIC_ASSERT(sizeof(key) >= sizeof(isc_hash_key),
     42 		      "sizeof(key) < sizeof(isc_hash_key)");
     43 	memmove(isc_hash_key, key, sizeof(isc_hash_key));
     44 }
     45 
     46 const void *
     47 isc_hash_get_initializer(void) {
     48 	return isc_hash_key;
     49 }
     50 
     51 void
     52 isc_hash_set_initializer(const void *initializer) {
     53 	REQUIRE(initializer != NULL);
     54 
     55 	memmove(isc_hash_key, initializer, sizeof(isc_hash_key));
     56 }
     57 
     58 void
     59 isc_hash32_init(isc_hash32_t *restrict state) {
     60 	isc_halfsiphash24_init(state, isc_hash_key);
     61 }
     62 
     63 void
     64 isc_hash32_hash(isc_hash32_t *restrict state, const void *data,
     65 		const size_t length, const bool case_sensitive) {
     66 	REQUIRE(length == 0 || data != NULL);
     67 
     68 	isc_halfsiphash24_hash(state, data, length, case_sensitive);
     69 }
     70 
     71 uint32_t
     72 isc_hash32_finalize(isc_hash32_t *restrict state) {
     73 	uint32_t hval;
     74 
     75 	isc_halfsiphash24_finalize(state, (uint8_t *)&hval);
     76 
     77 	return hval;
     78 }
     79 
     80 void
     81 isc_hash64_init(isc_hash64_t *restrict state) {
     82 	isc_siphash24_init(state, isc_hash_key);
     83 }
     84 
     85 void
     86 isc_hash64_hash(isc_hash64_t *restrict state, const void *data,
     87 		const size_t length, const bool case_sensitive) {
     88 	REQUIRE(length == 0 || data != NULL);
     89 
     90 	isc_siphash24_hash(state, data, length, case_sensitive);
     91 }
     92 
     93 uint64_t
     94 isc_hash64_finalize(isc_hash64_t *restrict state) {
     95 	uint64_t hval;
     96 
     97 	isc_siphash24_finalize(state, (uint8_t *)&hval);
     98 
     99 	return hval;
    100 }
    101