mirror of
https://gitlab.isc.org/isc-projects/bind9
synced 2025-08-29 13:38:26 +00:00
Remove unused isc_lfsr API
The isc_lfsr API was used to generate message IDs in the past. Currently, it's just cruft.
This commit is contained in:
Ondřej Surý
parent
f6d15d5af8
commit
bdca09aa8d
@ -41,7 +41,6 @@ libisc_la_HEADERS = \
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include/isc/iterated_hash.h \
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include/isc/lang.h \
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include/isc/lex.h \
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include/isc/lfsr.h \
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include/isc/lib.h \
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include/isc/likely.h \
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include/isc/list.h \
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@ -173,7 +172,6 @@ libisc_la_SOURCES = \
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httpd.c \
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iterated_hash.c \
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lex.c \
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lfsr.c \
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lib.c \
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log.c \
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md.c \
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@ -1,122 +0,0 @@
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/*
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* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* See the COPYRIGHT file distributed with this work for additional
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* information regarding copyright ownership.
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*/
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#ifndef ISC_LFSR_H
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#define ISC_LFSR_H 1
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/*! \file isc/lfsr.h */
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#include <inttypes.h>
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#include <isc/lang.h>
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#include <isc/types.h>
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typedef struct isc_lfsr isc_lfsr_t;
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/*%
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* This function is called when reseeding is needed. It is allowed to
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* modify any state in the LFSR in any way it sees fit OTHER THAN "bits".
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*
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* It MUST set "count" to a new value or the lfsr will never reseed again.
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*
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* Also, a reseed will never occur in the middle of an extraction. This
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* is purely an optimization, and is probably what one would want.
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*/
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typedef void (*isc_lfsrreseed_t)(isc_lfsr_t *, void *);
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/*%
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* The members of this structure can be used by the application, but care
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* needs to be taken to not change state once the lfsr is in operation.
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*/
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struct isc_lfsr {
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uint32_t state; /*%< previous state */
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unsigned int bits; /*%< length */
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uint32_t tap; /*%< bit taps */
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unsigned int count; /*%< reseed count (in BITS!) */
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isc_lfsrreseed_t reseed; /*%< reseed function */
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void * arg; /*%< reseed function argument */
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};
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ISC_LANG_BEGINDECLS
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void
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isc_lfsr_init(isc_lfsr_t *lfsr, uint32_t state, unsigned int bits, uint32_t tap,
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unsigned int count, isc_lfsrreseed_t reseed, void *arg);
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/*%<
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* Initialize an LFSR.
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*
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* Note:
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*
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*\li Putting untrusted values into this function will cause the LFSR to
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* generate (perhaps) non-maximal length sequences.
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*
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* Requires:
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*
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*\li lfsr != NULL
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*
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*\li 8 <= bits <= 32
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*
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*\li tap != 0
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*/
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void
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isc_lfsr_generate(isc_lfsr_t *lfsr, void *data, unsigned int count);
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/*%<
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* Returns "count" bytes of data from the LFSR.
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*
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* Requires:
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*
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*\li lfsr be valid.
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*
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*\li data != NULL.
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*
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*\li count > 0.
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*/
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void
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isc_lfsr_skip(isc_lfsr_t *lfsr, unsigned int skip);
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/*%<
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* Skip "skip" states.
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*
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* Requires:
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*
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*\li lfsr be valid.
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*/
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uint32_t
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isc_lfsr_generate32(isc_lfsr_t *lfsr1, isc_lfsr_t *lfsr2);
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/*%<
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* Given two LFSRs, use the current state from each to skip entries in the
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* other. The next states are then xor'd together and returned.
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*
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* WARNING:
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*
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*\li This function is used only for very, very low security data, such
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* as DNS message IDs where it is desired to have an unpredictable
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* stream of bytes that are harder to predict than a simple flooding
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* attack.
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*
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* Notes:
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*
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*\li Since the current state from each of the LFSRs is used to skip
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* state in the other, it is important that no state be leaked
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* from either LFSR.
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*
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* Requires:
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*
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*\li lfsr1 and lfsr2 be valid.
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*
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*\li 1 <= skipbits <= 31
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*/
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ISC_LANG_ENDDECLS
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#endif /* ISC_LFSR_H */
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151
lib/isc/lfsr.c
151
lib/isc/lfsr.c
@ -1,151 +0,0 @@
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/*
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* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*
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* See the COPYRIGHT file distributed with this work for additional
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* information regarding copyright ownership.
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*/
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/*! \file */
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#include <inttypes.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <isc/assertions.h>
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#include <isc/lfsr.h>
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#include <isc/util.h>
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#define VALID_LFSR(x) (x != NULL)
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void
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isc_lfsr_init(isc_lfsr_t *lfsr, uint32_t state, unsigned int bits, uint32_t tap,
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unsigned int count, isc_lfsrreseed_t reseed, void *arg) {
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REQUIRE(VALID_LFSR(lfsr));
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REQUIRE(8 <= bits && bits <= 32);
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REQUIRE(tap != 0);
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lfsr->state = state;
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lfsr->bits = bits;
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lfsr->tap = tap;
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lfsr->count = count;
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lfsr->reseed = reseed;
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lfsr->arg = arg;
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if (count == 0 && reseed != NULL) {
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reseed(lfsr, arg);
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}
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if (lfsr->state == 0) {
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lfsr->state = 0xffffffffU >> (32 - lfsr->bits);
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}
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}
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/*!
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* Return the next state of the lfsr.
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*/
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static inline uint32_t
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lfsr_generate(isc_lfsr_t *lfsr) {
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/*
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* If the previous state is zero, we must fill it with something
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* here, or we will begin to generate an extremely predictable output.
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*
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* First, give the reseed function a crack at it. If the state is
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* still 0, set it to all ones.
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*/
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if (lfsr->state == 0) {
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if (lfsr->reseed != NULL) {
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lfsr->reseed(lfsr, lfsr->arg);
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}
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if (lfsr->state == 0) {
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lfsr->state = 0xffffffffU >> (32 - lfsr->bits);
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}
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}
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if (lfsr->state & 0x01) {
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lfsr->state = (lfsr->state >> 1) ^ lfsr->tap;
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return (1);
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} else {
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lfsr->state >>= 1;
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return (0);
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}
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}
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void
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isc_lfsr_generate(isc_lfsr_t *lfsr, void *data, unsigned int count) {
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unsigned char *p;
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unsigned int bit;
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unsigned int byte;
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REQUIRE(VALID_LFSR(lfsr));
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REQUIRE(data != NULL);
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REQUIRE(count > 0);
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p = data;
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byte = count;
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while (byte--) {
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*p = 0;
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for (bit = 0; bit < 7; bit++) {
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*p |= lfsr_generate(lfsr);
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*p <<= 1;
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}
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*p |= lfsr_generate(lfsr);
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p++;
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}
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if (lfsr->count != 0 && lfsr->reseed != NULL) {
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if (lfsr->count <= count * 8) {
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lfsr->reseed(lfsr, lfsr->arg);
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} else {
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lfsr->count -= (count * 8);
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}
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}
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}
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static inline uint32_t
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lfsr_skipgenerate(isc_lfsr_t *lfsr, unsigned int skip) {
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while (skip--) {
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(void)lfsr_generate(lfsr);
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}
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(void)lfsr_generate(lfsr);
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return (lfsr->state);
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}
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/*
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* Skip "skip" states in "lfsr".
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*/
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void
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isc_lfsr_skip(isc_lfsr_t *lfsr, unsigned int skip) {
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REQUIRE(VALID_LFSR(lfsr));
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while (skip--) {
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(void)lfsr_generate(lfsr);
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}
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}
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/*
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* Skip states in lfsr1 and lfsr2 using the other's current state.
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* Return the final state of lfsr1 ^ lfsr2.
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*/
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uint32_t
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isc_lfsr_generate32(isc_lfsr_t *lfsr1, isc_lfsr_t *lfsr2) {
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uint32_t state1, state2;
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uint32_t skip1, skip2;
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REQUIRE(VALID_LFSR(lfsr1));
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REQUIRE(VALID_LFSR(lfsr2));
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skip1 = lfsr1->state & 0x01;
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skip2 = lfsr2->state & 0x01;
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/* cross-skip. */
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state1 = lfsr_skipgenerate(lfsr1, skip2);
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state2 = lfsr_skipgenerate(lfsr2, skip1);
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return (state1 ^ state2);
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}
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@ -328,10 +328,6 @@ isc_lex_setsourceline
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isc_lex_setsourcename
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isc_lex_setspecials
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isc_lex_ungettoken
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isc_lfsr_generate
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isc_lfsr_generate32
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isc_lfsr_init
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isc_lfsr_skip
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isc_lib_register
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isc_log_categorybyname
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isc_log_closefilelogs
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@ -131,9 +131,6 @@
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<ClInclude Include="..\include\isc\lex.h">
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<Filter>Library Header Files</Filter>
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</ClInclude>
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<ClInclude Include="..\include\isc\lfsr.h">
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<Filter>Library Header Files</Filter>
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</ClInclude>
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<ClInclude Include="..\include\isc\lib.h">
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<Filter>Library Header Files</Filter>
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</ClInclude>
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@ -515,9 +512,6 @@
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<ClCompile Include="..\lex.c">
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<Filter>Library Source Files</Filter>
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</ClCompile>
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<ClCompile Include="..\lfsr.c">
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<Filter>Library Source Files</Filter>
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</ClCompile>
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<ClCompile Include="..\lib.c">
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<Filter>Library Source Files</Filter>
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</ClCompile>
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@ -326,7 +326,6 @@ copy InstallFiles ..\Build\Release\
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<ClInclude Include="..\include\isc\json.h" />
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<ClInclude Include="..\include\isc\lang.h" />
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<ClInclude Include="..\include\isc\lex.h" />
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<ClInclude Include="..\include\isc\lfsr.h" />
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<ClInclude Include="..\include\isc\lib.h" />
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<ClInclude Include="..\include\isc\list.h" />
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<ClInclude Include="..\include\isc\log.h" />
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@ -434,7 +433,6 @@ copy InstallFiles ..\Build\Release\
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<ClCompile Include="..\httpd.c" />
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<ClCompile Include="..\iterated_hash.c" />
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<ClCompile Include="..\lex.c" />
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<ClCompile Include="..\lfsr.c" />
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<ClCompile Include="..\lib.c" />
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<ClCompile Include="..\log.c" />
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<ClCompile Include="..\md.c" />
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@ -1955,7 +1955,6 @@
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./lib/isc/include/isc/iterated_hash.h C 2008,2014,2016,2018,2019,2020
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./lib/isc/include/isc/lang.h C 1999,2000,2001,2004,2005,2006,2007,2016,2018,2019,2020
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./lib/isc/include/isc/lex.h C 1998,1999,2000,2001,2002,2004,2005,2007,2008,2015,2016,2017,2018,2019,2020
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./lib/isc/include/isc/lfsr.h C 1999,2000,2001,2004,2005,2006,2007,2016,2018,2019,2020
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./lib/isc/include/isc/lib.h C 1999,2000,2001,2004,2005,2006,2007,2009,2016,2018,2019,2020
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./lib/isc/include/isc/likely.h C 2017,2018,2019,2020
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./lib/isc/include/isc/list.h C 1997,1998,1999,2000,2001,2002,2004,2006,2007,2011,2012,2013,2016,2018,2019,2020
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@ -2012,7 +2011,6 @@
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./lib/isc/include/pkcs11/pkcs11.h X 2019,2020
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./lib/isc/iterated_hash.c C 2006,2008,2009,2016,2018,2019,2020
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./lib/isc/lex.c C 1998,1999,2000,2001,2002,2003,2004,2005,2007,2013,2014,2015,2016,2017,2018,2019,2020
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./lib/isc/lfsr.c C 1999,2000,2001,2002,2004,2005,2007,2016,2018,2019,2020
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./lib/isc/lib.c C 1999,2000,2001,2004,2005,2007,2009,2013,2014,2015,2016,2018,2019,2020
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./lib/isc/log.c C 1999,2000,2001,2002,2003,2004,2005,2006,2007,2009,2011,2012,2013,2014,2016,2017,2018,2019,2020
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./lib/isc/md.c C 2018,2019,2020
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