rdataset.c revision 9c3531d72aeaad6c5f01efe6a1c82023e1379e4d
/*
* Copyright (C) 1999, 2000 Internet Software Consortium.
*
* Permission to use, copy, modify, and 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM 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: rdataset.c,v 1.46 2000/06/22 21:54:42 tale Exp $ */
#include <config.h>
#include <stdlib.h>
#include <isc/buffer.h>
#include <isc/util.h>
#include <dns/name.h>
#include <dns/ncache.h>
#include <dns/rdata.h>
#include <dns/rdataset.h>
#include <dns/compress.h>
void
dns_rdataset_init(dns_rdataset_t *rdataset) {
/*
* Make 'rdataset' a valid, disassociated rdataset.
*/
REQUIRE(rdataset != NULL);
rdataset->magic = DNS_RDATASET_MAGIC;
rdataset->methods = NULL;
ISC_LINK_INIT(rdataset, link);
rdataset->rdclass = 0;
rdataset->type = 0;
rdataset->ttl = 0;
rdataset->trust = 0;
rdataset->covers = 0;
rdataset->attributes = 0;
rdataset->private1 = NULL;
rdataset->private2 = NULL;
rdataset->private3 = NULL;
rdataset->private4 = NULL;
rdataset->private5 = NULL;
}
void
dns_rdataset_invalidate(dns_rdataset_t *rdataset) {
/*
* Invalidate 'rdataset'.
*/
REQUIRE(DNS_RDATASET_VALID(rdataset));
REQUIRE(rdataset->methods == NULL);
rdataset->magic = 0;
ISC_LINK_INIT(rdataset, link);
rdataset->rdclass = 0;
rdataset->type = 0;
rdataset->ttl = 0;
rdataset->trust = 0;
rdataset->covers = 0;
rdataset->attributes = 0;
rdataset->private1 = NULL;
rdataset->private2 = NULL;
rdataset->private3 = NULL;
rdataset->private4 = NULL;
rdataset->private5 = NULL;
}
void
dns_rdataset_disassociate(dns_rdataset_t *rdataset) {
/*
* Disassociate 'rdataset' from its rdata, allowing it to be reused.
*/
REQUIRE(DNS_RDATASET_VALID(rdataset));
REQUIRE(rdataset->methods != NULL);
(rdataset->methods->disassociate)(rdataset);
rdataset->methods = NULL;
ISC_LINK_INIT(rdataset, link);
rdataset->rdclass = 0;
rdataset->type = 0;
rdataset->ttl = 0;
rdataset->trust = 0;
rdataset->covers = 0;
rdataset->attributes = 0;
rdataset->private1 = NULL;
rdataset->private2 = NULL;
rdataset->private3 = NULL;
rdataset->private4 = NULL;
rdataset->private5 = NULL;
}
isc_boolean_t
dns_rdataset_isassociated(dns_rdataset_t *rdataset) {
/*
* Is 'rdataset' associated?
*/
REQUIRE(DNS_RDATASET_VALID(rdataset));
if (rdataset->methods != NULL)
return (ISC_TRUE);
return (ISC_FALSE);
}
static void
question_disassociate(dns_rdataset_t *rdataset) {
(void)rdataset;
}
static isc_result_t
question_cursor(dns_rdataset_t *rdataset) {
(void)rdataset;
return (ISC_R_NOMORE);
}
static void
question_current(dns_rdataset_t *rdataset, dns_rdata_t *rdata) {
/*
* This routine should never be called.
*/
(void)rdataset;
(void)rdata;
REQUIRE(0);
}
static void
question_clone(dns_rdataset_t *source, dns_rdataset_t *target) {
*target = *source;
}
static unsigned int
question_count(dns_rdataset_t *rdataset) {
/*
* This routine should never be called.
*/
(void)rdataset;
REQUIRE(0);
return (0);
}
static dns_rdatasetmethods_t question_methods = {
question_disassociate,
question_cursor,
question_cursor,
question_current,
question_clone,
question_count
};
void
dns_rdataset_makequestion(dns_rdataset_t *rdataset, dns_rdataclass_t rdclass,
dns_rdatatype_t type)
{
/*
* Make 'rdataset' a valid, associated, question rdataset, with a
* question class of 'rdclass' and type 'type'.
*/
REQUIRE(DNS_RDATASET_VALID(rdataset));
REQUIRE(rdataset->methods == NULL);
rdataset->methods = &question_methods;
rdataset->rdclass = rdclass;
rdataset->type = type;
rdataset->attributes |= DNS_RDATASETATTR_QUESTION;
}
unsigned int
dns_rdataset_count(dns_rdataset_t *rdataset) {
/*
* Return the number of records in 'rdataset'.
*/
REQUIRE(DNS_RDATASET_VALID(rdataset));
REQUIRE(rdataset->methods != NULL);
return ((rdataset->methods->count)(rdataset));
}
void
dns_rdataset_clone(dns_rdataset_t *source, dns_rdataset_t *target) {
/*
* Make 'target' refer to the same rdataset as 'source'.
*/
REQUIRE(DNS_RDATASET_VALID(source));
REQUIRE(source->methods != NULL);
REQUIRE(DNS_RDATASET_VALID(target));
REQUIRE(target->methods == NULL);
(source->methods->clone)(source, target);
}
isc_result_t
dns_rdataset_first(dns_rdataset_t *rdataset) {
/*
* Move the rdata cursor to the first rdata in the rdataset (if any).
*/
REQUIRE(DNS_RDATASET_VALID(rdataset));
REQUIRE(rdataset->methods != NULL);
return ((rdataset->methods->first)(rdataset));
}
isc_result_t
dns_rdataset_next(dns_rdataset_t *rdataset) {
/*
* Move the rdata cursor to the next rdata in the rdataset (if any).
*/
REQUIRE(DNS_RDATASET_VALID(rdataset));
REQUIRE(rdataset->methods != NULL);
return ((rdataset->methods->next)(rdataset));
}
void
dns_rdataset_current(dns_rdataset_t *rdataset, dns_rdata_t *rdata) {
/*
* Make 'rdata' refer to the current rdata.
*/
REQUIRE(DNS_RDATASET_VALID(rdataset));
REQUIRE(rdataset->methods != NULL);
(rdataset->methods->current)(rdataset, rdata);
}
#define MAX_SHUFFLE 32
#define WANT_FIXED(r) (((r)->attributes & DNS_RDATASETATTR_FIXEDORDER) != 0)
#define WANT_RANDOM(r) (((r)->attributes & DNS_RDATASETATTR_RANDOMIZE) != 0)
isc_result_t
dns_rdataset_towire(dns_rdataset_t *rdataset,
dns_name_t *owner_name,
dns_compress_t *cctx,
isc_buffer_t *target,
unsigned int *countp)
{
dns_rdata_t rdata;
isc_region_t r;
isc_result_t result;
unsigned int i, count, tcount, choice;
isc_buffer_t savedbuffer, rdlen;
unsigned int headlen;
isc_boolean_t question = ISC_FALSE;
isc_boolean_t shuffle = ISC_FALSE;
dns_rdata_t shuffled[MAX_SHUFFLE];
/*
* Convert 'rdataset' to wire format, compressing names as specified
* in cctx, and storing the result in 'target'.
*/
REQUIRE(DNS_RDATASET_VALID(rdataset));
REQUIRE(countp != NULL);
count = 0;
if ((rdataset->attributes & DNS_RDATASETATTR_QUESTION) != 0) {
question = ISC_TRUE;
count = 1;
result = dns_rdataset_first(rdataset);
INSIST(result == ISC_R_NOMORE);
} else if (rdataset->type == 0) {
/*
* This is a negative caching rdataset.
*/
return (dns_ncache_towire(rdataset, cctx, target, countp));
} else {
count = (rdataset->methods->count)(rdataset);
result = dns_rdataset_first(rdataset);
if (result == ISC_R_NOMORE)
return (ISC_R_SUCCESS);
if (result != ISC_R_SUCCESS)
return (result);
}
choice = 0;
if (!question && count > 1 && !WANT_FIXED(rdataset)) {
/*
* We'll only shuffle if we've got enough slots in our
* deck.
*
* There's no point to shuffling SIGs.
*/
if (count <= MAX_SHUFFLE &&
rdataset->type != dns_rdatatype_sig) {
shuffle = ISC_TRUE;
/*
* First we get handles to all of the rdata.
*/
i = 0;
do {
INSIST(i < count);
dns_rdataset_current(rdataset, &shuffled[i]);
i++;
result = dns_rdataset_next(rdataset);
} while (result == ISC_R_SUCCESS);
if (result != ISC_R_NOMORE)
return (result);
INSIST(i == count);
/*
* Now we shuffle.
*/
if (WANT_RANDOM(rdataset)) {
/*
* "Random" order.
*/
tcount = count;
for (i = 0; i < count; i++) {
choice = (((unsigned int)rand()) >> 3)
% tcount;
rdata = shuffled[i];
shuffled[i] = shuffled[i + choice];
shuffled[i + choice] = rdata;
tcount--;
}
choice = 0;
} else {
/*
* "Cyclic" order.
*/
choice = (((unsigned int)rand()) >> 3) % count;
}
}
}
savedbuffer = *target;
i = choice;
tcount = 0;
do {
/*
* Copy out the name, type, class, ttl.
*/
dns_compress_setmethods(cctx, DNS_COMPRESS_GLOBAL14);
result = dns_name_towire(owner_name, cctx, target);
if (result != ISC_R_SUCCESS)
goto rollback;
headlen = sizeof(dns_rdataclass_t) + sizeof(dns_rdatatype_t);
if (!question)
headlen += sizeof(dns_ttl_t)
+ 2; /* XXX 2 for rdata len */
isc_buffer_availableregion(target, &r);
if (r.length < headlen) {
result = ISC_R_NOSPACE;
goto rollback;
}
isc_buffer_putuint16(target, rdataset->type);
isc_buffer_putuint16(target, rdataset->rdclass);
if (!question) {
isc_buffer_putuint32(target, rdataset->ttl);
/*
* Save space for rdlen.
*/
rdlen = *target;
isc_buffer_add(target, 2);
/*
* Copy out the rdata
*/
if (shuffle)
rdata = shuffled[i];
else
dns_rdataset_current(rdataset, &rdata);
result = dns_rdata_towire(&rdata, cctx, target);
if (result != ISC_R_SUCCESS)
goto rollback;
INSIST((target->used >= rdlen.used + 2) &&
(target->used - rdlen.used - 2 < 65536));
isc_buffer_putuint16(&rdlen,
(isc_uint16_t)(target->used -
rdlen.used - 2));
}
if (shuffle) {
i++;
/*
* Wrap around in case we're doing cyclic ordering.
*/
if (i == count)
i = 0;
tcount++;
if (tcount == count)
result = ISC_R_NOMORE;
else
result = ISC_R_SUCCESS;
} else
result = dns_rdataset_next(rdataset);
} while (result == ISC_R_SUCCESS);
if (result != ISC_R_NOMORE)
goto rollback;
*countp += count;
return (ISC_R_SUCCESS);
rollback:
INSIST(savedbuffer.used < 65536);
dns_compress_rollback(cctx, (isc_uint16_t)savedbuffer.used);
*countp = 0;
*target = savedbuffer;
return (result);
}
isc_result_t
dns_rdataset_additionaldata(dns_rdataset_t *rdataset,
dns_additionaldatafunc_t add, void *arg)
{
dns_rdata_t rdata;
isc_result_t result;
/*
* For each rdata in rdataset, call 'add' for each name and type in the
* rdata which is subject to additional section processing.
*/
REQUIRE(DNS_RDATASET_VALID(rdataset));
REQUIRE((rdataset->attributes & DNS_RDATASETATTR_QUESTION) == 0);
result = dns_rdataset_first(rdataset);
if (result != ISC_R_SUCCESS)
return (result);
do {
dns_rdataset_current(rdataset, &rdata);
result = dns_rdata_additionaldata(&rdata, add, arg);
if (result == ISC_R_SUCCESS)
result = dns_rdataset_next(rdataset);
} while (result == ISC_R_SUCCESS);
if (result != ISC_R_NOMORE)
return (result);
return (ISC_R_SUCCESS);
}