/contrib/bind9/lib/dns/compress.c
https://bitbucket.org/freebsd/freebsd-head/ · C · 341 lines · 240 code · 60 blank · 41 comment · 43 complexity · 0968bdaaa757f30faed0787ebfb87b70 MD5 · raw file
- /*
- * Copyright (C) 2004-2007 Internet Systems Consortium, Inc. ("ISC")
- * Copyright (C) 1999-2001 Internet Software Consortium.
- *
- * Permission to use, copy, modify, and/or distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
- * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
- * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
- * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
- * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
- * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
- * PERFORMANCE OF THIS SOFTWARE.
- */
- /* $Id: compress.c,v 1.59 2007/06/19 23:47:16 tbox Exp $ */
- /*! \file */
- #define DNS_NAME_USEINLINE 1
- #include <config.h>
- #include <isc/mem.h>
- #include <isc/string.h>
- #include <isc/util.h>
- #include <dns/compress.h>
- #include <dns/fixedname.h>
- #include <dns/rbt.h>
- #include <dns/result.h>
- #define CCTX_MAGIC ISC_MAGIC('C', 'C', 'T', 'X')
- #define VALID_CCTX(x) ISC_MAGIC_VALID(x, CCTX_MAGIC)
- #define DCTX_MAGIC ISC_MAGIC('D', 'C', 'T', 'X')
- #define VALID_DCTX(x) ISC_MAGIC_VALID(x, DCTX_MAGIC)
- /***
- *** Compression
- ***/
- isc_result_t
- dns_compress_init(dns_compress_t *cctx, int edns, isc_mem_t *mctx) {
- unsigned int i;
- REQUIRE(cctx != NULL);
- REQUIRE(mctx != NULL); /* See: rdataset.c:towiresorted(). */
- cctx->allowed = 0;
- cctx->edns = edns;
- for (i = 0; i < DNS_COMPRESS_TABLESIZE; i++)
- cctx->table[i] = NULL;
- cctx->mctx = mctx;
- cctx->count = 0;
- cctx->magic = CCTX_MAGIC;
- return (ISC_R_SUCCESS);
- }
- void
- dns_compress_invalidate(dns_compress_t *cctx) {
- dns_compressnode_t *node;
- unsigned int i;
- REQUIRE(VALID_CCTX(cctx));
- cctx->magic = 0;
- for (i = 0; i < DNS_COMPRESS_TABLESIZE; i++) {
- while (cctx->table[i] != NULL) {
- node = cctx->table[i];
- cctx->table[i] = cctx->table[i]->next;
- if (node->count < DNS_COMPRESS_INITIALNODES)
- continue;
- isc_mem_put(cctx->mctx, node, sizeof(*node));
- }
- }
- cctx->allowed = 0;
- cctx->edns = -1;
- }
- void
- dns_compress_setmethods(dns_compress_t *cctx, unsigned int allowed) {
- REQUIRE(VALID_CCTX(cctx));
- cctx->allowed &= ~DNS_COMPRESS_ALL;
- cctx->allowed |= (allowed & DNS_COMPRESS_ALL);
- }
- unsigned int
- dns_compress_getmethods(dns_compress_t *cctx) {
- REQUIRE(VALID_CCTX(cctx));
- return (cctx->allowed & DNS_COMPRESS_ALL);
- }
- void
- dns_compress_setsensitive(dns_compress_t *cctx, isc_boolean_t sensitive) {
- REQUIRE(VALID_CCTX(cctx));
- if (sensitive)
- cctx->allowed |= DNS_COMPRESS_CASESENSITIVE;
- else
- cctx->allowed &= ~DNS_COMPRESS_CASESENSITIVE;
- }
- isc_boolean_t
- dns_compress_getsensitive(dns_compress_t *cctx) {
- REQUIRE(VALID_CCTX(cctx));
- return (ISC_TF((cctx->allowed & DNS_COMPRESS_CASESENSITIVE) != 0));
- }
- int
- dns_compress_getedns(dns_compress_t *cctx) {
- REQUIRE(VALID_CCTX(cctx));
- return (cctx->edns);
- }
- #define NODENAME(node, name) \
- do { \
- (name)->length = (node)->r.length; \
- (name)->labels = (node)->labels; \
- (name)->ndata = (node)->r.base; \
- (name)->attributes = DNS_NAMEATTR_ABSOLUTE; \
- } while (0)
- /*
- * Find the longest match of name in the table.
- * If match is found return ISC_TRUE. prefix, suffix and offset are updated.
- * If no match is found return ISC_FALSE.
- */
- isc_boolean_t
- dns_compress_findglobal(dns_compress_t *cctx, const dns_name_t *name,
- dns_name_t *prefix, isc_uint16_t *offset)
- {
- dns_name_t tname, nname;
- dns_compressnode_t *node = NULL;
- unsigned int labels, hash, n;
- REQUIRE(VALID_CCTX(cctx));
- REQUIRE(dns_name_isabsolute(name) == ISC_TRUE);
- REQUIRE(offset != NULL);
- if (cctx->count == 0)
- return (ISC_FALSE);
- labels = dns_name_countlabels(name);
- INSIST(labels > 0);
- dns_name_init(&tname, NULL);
- dns_name_init(&nname, NULL);
- for (n = 0; n < labels - 1; n++) {
- dns_name_getlabelsequence(name, n, labels - n, &tname);
- hash = dns_name_hash(&tname, ISC_FALSE) %
- DNS_COMPRESS_TABLESIZE;
- for (node = cctx->table[hash]; node != NULL; node = node->next)
- {
- NODENAME(node, &nname);
- if ((cctx->allowed & DNS_COMPRESS_CASESENSITIVE) != 0) {
- if (dns_name_caseequal(&nname, &tname))
- break;
- } else {
- if (dns_name_equal(&nname, &tname))
- break;
- }
- }
- if (node != NULL)
- break;
- }
- /*
- * If node == NULL, we found no match at all.
- */
- if (node == NULL)
- return (ISC_FALSE);
- if (n == 0)
- dns_name_reset(prefix);
- else
- dns_name_getlabelsequence(name, 0, n, prefix);
- *offset = node->offset;
- return (ISC_TRUE);
- }
- static inline unsigned int
- name_length(const dns_name_t *name) {
- isc_region_t r;
- dns_name_toregion(name, &r);
- return (r.length);
- }
- void
- dns_compress_add(dns_compress_t *cctx, const dns_name_t *name,
- const dns_name_t *prefix, isc_uint16_t offset)
- {
- dns_name_t tname;
- unsigned int start;
- unsigned int n;
- unsigned int count;
- unsigned int hash;
- dns_compressnode_t *node;
- unsigned int length;
- unsigned int tlength;
- isc_uint16_t toffset;
- REQUIRE(VALID_CCTX(cctx));
- REQUIRE(dns_name_isabsolute(name));
- dns_name_init(&tname, NULL);
- n = dns_name_countlabels(name);
- count = dns_name_countlabels(prefix);
- if (dns_name_isabsolute(prefix))
- count--;
- start = 0;
- length = name_length(name);
- while (count > 0) {
- if (offset >= 0x4000)
- break;
- dns_name_getlabelsequence(name, start, n, &tname);
- hash = dns_name_hash(&tname, ISC_FALSE) %
- DNS_COMPRESS_TABLESIZE;
- tlength = name_length(&tname);
- toffset = (isc_uint16_t)(offset + (length - tlength));
- /*
- * Create a new node and add it.
- */
- if (cctx->count < DNS_COMPRESS_INITIALNODES)
- node = &cctx->initialnodes[cctx->count];
- else {
- node = isc_mem_get(cctx->mctx,
- sizeof(dns_compressnode_t));
- if (node == NULL)
- return;
- }
- node->count = cctx->count++;
- node->offset = toffset;
- dns_name_toregion(&tname, &node->r);
- node->labels = (isc_uint8_t)dns_name_countlabels(&tname);
- node->next = cctx->table[hash];
- cctx->table[hash] = node;
- start++;
- n--;
- count--;
- }
- }
- void
- dns_compress_rollback(dns_compress_t *cctx, isc_uint16_t offset) {
- unsigned int i;
- dns_compressnode_t *node;
- REQUIRE(VALID_CCTX(cctx));
- for (i = 0; i < DNS_COMPRESS_TABLESIZE; i++) {
- node = cctx->table[i];
- /*
- * This relies on nodes with greater offsets being
- * closer to the beginning of the list, and the
- * items with the greatest offsets being at the end
- * of the initialnodes[] array.
- */
- while (node != NULL && node->offset >= offset) {
- cctx->table[i] = node->next;
- if (node->count >= DNS_COMPRESS_INITIALNODES)
- isc_mem_put(cctx->mctx, node, sizeof(*node));
- cctx->count--;
- node = cctx->table[i];
- }
- }
- }
- /***
- *** Decompression
- ***/
- void
- dns_decompress_init(dns_decompress_t *dctx, int edns,
- dns_decompresstype_t type) {
- REQUIRE(dctx != NULL);
- REQUIRE(edns >= -1 && edns <= 255);
- dctx->allowed = DNS_COMPRESS_NONE;
- dctx->edns = edns;
- dctx->type = type;
- dctx->magic = DCTX_MAGIC;
- }
- void
- dns_decompress_invalidate(dns_decompress_t *dctx) {
- REQUIRE(VALID_DCTX(dctx));
- dctx->magic = 0;
- }
- void
- dns_decompress_setmethods(dns_decompress_t *dctx, unsigned int allowed) {
- REQUIRE(VALID_DCTX(dctx));
- switch (dctx->type) {
- case DNS_DECOMPRESS_ANY:
- dctx->allowed = DNS_COMPRESS_ALL;
- break;
- case DNS_DECOMPRESS_NONE:
- dctx->allowed = DNS_COMPRESS_NONE;
- break;
- case DNS_DECOMPRESS_STRICT:
- dctx->allowed = allowed;
- break;
- }
- }
- unsigned int
- dns_decompress_getmethods(dns_decompress_t *dctx) {
- REQUIRE(VALID_DCTX(dctx));
- return (dctx->allowed);
- }
- int
- dns_decompress_edns(dns_decompress_t *dctx) {
- REQUIRE(VALID_DCTX(dctx));
- return (dctx->edns);
- }
- dns_decompresstype_t
- dns_decompress_type(dns_decompress_t *dctx) {
- REQUIRE(VALID_DCTX(dctx));
- return (dctx->type);
- }