405 lines
11 KiB
C
405 lines
11 KiB
C
/*
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* Copyright (C) 2004-2007, 2009 Internet Systems Consortium, Inc. ("ISC")
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* Copyright (C) 2003 Internet Software Consortium.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
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* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
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* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
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* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
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* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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* PERFORMANCE OF THIS SOFTWARE.
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*/
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/* $Id: hash.c,v 1.16 2009/09/01 00:22:28 jinmei Exp $ */
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/*! \file
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* Some portion of this code was derived from universal hash function
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* libraries of Rice University.
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\section license UH Universal Hashing Library
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Copyright ((c)) 2002, Rice University
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above
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copyright notice, this list of conditions and the following
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disclaimer in the documentation and/or other materials provided
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with the distribution.
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* Neither the name of Rice University (RICE) nor the names of its
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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This software is provided by RICE and the contributors on an "as is"
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basis, without any representations or warranties of any kind, express
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or implied including, but not limited to, representations or
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warranties of non-infringement, merchantability or fitness for a
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particular purpose. In no event shall RICE or contributors be liable
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for any direct, indirect, incidental, special, exemplary, or
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consequential damages (including, but not limited to, procurement of
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substitute goods or services; loss of use, data, or profits; or
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business interruption) however caused and on any theory of liability,
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whether in contract, strict liability, or tort (including negligence
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or otherwise) arising in any way out of the use of this software, even
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if advised of the possibility of such damage.
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*/
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#include <config.h>
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#include <isc/entropy.h>
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#include <isc/hash.h>
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#include <isc/mem.h>
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#include <isc/magic.h>
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#include <isc/mutex.h>
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#include <isc/once.h>
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#include <isc/random.h>
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#include <isc/refcount.h>
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#include <isc/string.h>
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#include <isc/util.h>
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#define HASH_MAGIC ISC_MAGIC('H', 'a', 's', 'h')
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#define VALID_HASH(h) ISC_MAGIC_VALID((h), HASH_MAGIC)
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/*%
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* A large 32-bit prime number that specifies the range of the hash output.
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*/
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#define PRIME32 0xFFFFFFFB /* 2^32 - 5 */
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/*@{*/
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/*%
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* Types of random seed and hash accumulator. Perhaps they can be system
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* dependent.
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*/
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typedef isc_uint32_t hash_accum_t;
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typedef isc_uint16_t hash_random_t;
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/*@}*/
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/*% isc hash structure */
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struct isc_hash {
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unsigned int magic;
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isc_mem_t *mctx;
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isc_mutex_t lock;
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isc_boolean_t initialized;
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isc_refcount_t refcnt;
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isc_entropy_t *entropy; /*%< entropy source */
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unsigned int limit; /*%< upper limit of key length */
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size_t vectorlen; /*%< size of the vector below */
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hash_random_t *rndvector; /*%< random vector for universal hashing */
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};
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static isc_mutex_t createlock;
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static isc_once_t once = ISC_ONCE_INIT;
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static isc_hash_t *hash = NULL;
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static unsigned char maptolower[] = {
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0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
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0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
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0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
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0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
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0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
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0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
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0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
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0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
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0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
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0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
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0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
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0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
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0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
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0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
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0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
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0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,
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0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
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0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
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0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
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0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
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0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
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0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
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0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7,
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0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
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0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7,
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0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
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0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7,
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0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf,
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0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
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0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,
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0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,
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0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff
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};
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isc_result_t
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isc_hash_ctxcreate(isc_mem_t *mctx, isc_entropy_t *entropy,
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unsigned int limit, isc_hash_t **hctxp)
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{
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isc_result_t result;
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isc_hash_t *hctx;
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size_t vlen;
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hash_random_t *rv;
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hash_accum_t overflow_limit;
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REQUIRE(mctx != NULL);
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REQUIRE(hctxp != NULL && *hctxp == NULL);
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/*
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* Overflow check. Since our implementation only does a modulo
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* operation at the last stage of hash calculation, the accumulator
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* must not overflow.
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*/
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overflow_limit =
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1 << (((sizeof(hash_accum_t) - sizeof(hash_random_t))) * 8);
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if (overflow_limit < (limit + 1) * 0xff)
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return (ISC_R_RANGE);
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hctx = isc_mem_get(mctx, sizeof(isc_hash_t));
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if (hctx == NULL)
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return (ISC_R_NOMEMORY);
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vlen = sizeof(hash_random_t) * (limit + 1);
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rv = isc_mem_get(mctx, vlen);
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if (rv == NULL) {
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result = ISC_R_NOMEMORY;
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goto errout;
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}
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/*
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* We need a lock.
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*/
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result = isc_mutex_init(&hctx->lock);
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if (result != ISC_R_SUCCESS)
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goto errout;
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/*
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* From here down, no failures will/can occur.
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*/
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hctx->magic = HASH_MAGIC;
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hctx->mctx = NULL;
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isc_mem_attach(mctx, &hctx->mctx);
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hctx->initialized = ISC_FALSE;
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result = isc_refcount_init(&hctx->refcnt, 1);
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if (result != ISC_R_SUCCESS)
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goto cleanup_lock;
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hctx->entropy = NULL;
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hctx->limit = limit;
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hctx->vectorlen = vlen;
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hctx->rndvector = rv;
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#ifdef BIND9
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if (entropy != NULL)
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isc_entropy_attach(entropy, &hctx->entropy);
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#else
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UNUSED(entropy);
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#endif
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*hctxp = hctx;
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return (ISC_R_SUCCESS);
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cleanup_lock:
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DESTROYLOCK(&hctx->lock);
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errout:
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isc_mem_put(mctx, hctx, sizeof(isc_hash_t));
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if (rv != NULL)
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isc_mem_put(mctx, rv, vlen);
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return (result);
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}
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static void
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initialize_lock(void) {
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RUNTIME_CHECK(isc_mutex_init(&createlock) == ISC_R_SUCCESS);
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}
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isc_result_t
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isc_hash_create(isc_mem_t *mctx, isc_entropy_t *entropy, size_t limit) {
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isc_result_t result = ISC_R_SUCCESS;
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REQUIRE(mctx != NULL);
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INSIST(hash == NULL);
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RUNTIME_CHECK(isc_once_do(&once, initialize_lock) == ISC_R_SUCCESS);
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LOCK(&createlock);
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if (hash == NULL)
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result = isc_hash_ctxcreate(mctx, entropy, limit, &hash);
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UNLOCK(&createlock);
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return (result);
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}
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void
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isc_hash_ctxinit(isc_hash_t *hctx) {
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LOCK(&hctx->lock);
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if (hctx->initialized == ISC_TRUE)
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goto out;
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if (hctx->entropy) {
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#ifdef BIND9
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isc_result_t result;
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result = isc_entropy_getdata(hctx->entropy,
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hctx->rndvector, hctx->vectorlen,
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NULL, 0);
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INSIST(result == ISC_R_SUCCESS);
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#else
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INSIST(0);
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#endif
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} else {
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isc_uint32_t pr;
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unsigned int i, copylen;
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unsigned char *p;
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p = (unsigned char *)hctx->rndvector;
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for (i = 0; i < hctx->vectorlen; i += copylen, p += copylen) {
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isc_random_get(&pr);
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if (i + sizeof(pr) <= hctx->vectorlen)
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copylen = sizeof(pr);
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else
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copylen = hctx->vectorlen - i;
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memcpy(p, &pr, copylen);
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}
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INSIST(p == (unsigned char *)hctx->rndvector +
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hctx->vectorlen);
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}
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hctx->initialized = ISC_TRUE;
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out:
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UNLOCK(&hctx->lock);
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}
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void
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isc_hash_init() {
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INSIST(hash != NULL && VALID_HASH(hash));
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isc_hash_ctxinit(hash);
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}
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void
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isc_hash_ctxattach(isc_hash_t *hctx, isc_hash_t **hctxp) {
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REQUIRE(VALID_HASH(hctx));
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REQUIRE(hctxp != NULL && *hctxp == NULL);
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isc_refcount_increment(&hctx->refcnt, NULL);
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*hctxp = hctx;
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}
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static void
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destroy(isc_hash_t **hctxp) {
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isc_hash_t *hctx;
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isc_mem_t *mctx;
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unsigned char canary0[4], canary1[4];
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REQUIRE(hctxp != NULL && *hctxp != NULL);
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hctx = *hctxp;
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*hctxp = NULL;
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LOCK(&hctx->lock);
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isc_refcount_destroy(&hctx->refcnt);
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mctx = hctx->mctx;
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#ifdef BIND9
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if (hctx->entropy != NULL)
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isc_entropy_detach(&hctx->entropy);
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#endif
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if (hctx->rndvector != NULL)
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isc_mem_put(mctx, hctx->rndvector, hctx->vectorlen);
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UNLOCK(&hctx->lock);
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DESTROYLOCK(&hctx->lock);
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memcpy(canary0, hctx + 1, sizeof(canary0));
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memset(hctx, 0, sizeof(isc_hash_t));
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memcpy(canary1, hctx + 1, sizeof(canary1));
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INSIST(memcmp(canary0, canary1, sizeof(canary0)) == 0);
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isc_mem_put(mctx, hctx, sizeof(isc_hash_t));
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isc_mem_detach(&mctx);
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}
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void
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isc_hash_ctxdetach(isc_hash_t **hctxp) {
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isc_hash_t *hctx;
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unsigned int refs;
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REQUIRE(hctxp != NULL && VALID_HASH(*hctxp));
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hctx = *hctxp;
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isc_refcount_decrement(&hctx->refcnt, &refs);
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if (refs == 0)
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destroy(&hctx);
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*hctxp = NULL;
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}
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void
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isc_hash_destroy() {
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unsigned int refs;
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INSIST(hash != NULL && VALID_HASH(hash));
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isc_refcount_decrement(&hash->refcnt, &refs);
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INSIST(refs == 0);
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destroy(&hash);
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}
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static inline unsigned int
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hash_calc(isc_hash_t *hctx, const unsigned char *key, unsigned int keylen,
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isc_boolean_t case_sensitive)
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{
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hash_accum_t partial_sum = 0;
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hash_random_t *p = hctx->rndvector;
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unsigned int i = 0;
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/* Make it sure that the hash context is initialized. */
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if (hctx->initialized == ISC_FALSE)
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isc_hash_ctxinit(hctx);
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if (case_sensitive) {
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for (i = 0; i < keylen; i++)
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partial_sum += key[i] * (hash_accum_t)p[i];
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} else {
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for (i = 0; i < keylen; i++)
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partial_sum += maptolower[key[i]] * (hash_accum_t)p[i];
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}
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partial_sum += p[i];
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return ((unsigned int)(partial_sum % PRIME32));
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}
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unsigned int
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isc_hash_ctxcalc(isc_hash_t *hctx, const unsigned char *key,
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unsigned int keylen, isc_boolean_t case_sensitive)
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{
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REQUIRE(hctx != NULL && VALID_HASH(hctx));
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REQUIRE(keylen <= hctx->limit);
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return (hash_calc(hctx, key, keylen, case_sensitive));
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}
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unsigned int
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isc_hash_calc(const unsigned char *key, unsigned int keylen,
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isc_boolean_t case_sensitive)
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{
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INSIST(hash != NULL && VALID_HASH(hash));
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REQUIRE(keylen <= hash->limit);
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return (hash_calc(hash, key, keylen, case_sensitive));
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}
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