compress.c revision 70e5a7403f0e0a3bd292b8287c5fed5772c15270
/*
* 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);
}