message.c

bind 9.3结合mysql数据库

	while (rdatalist != NULL) {
		ISC_LIST_UNLINK(msg->freerdatalist, rdatalist, link);
		rdatalist = ISC_LIST_HEAD(msg->freerdatalist);
	}

	dynbuf = ISC_LIST_HEAD(msg->scratchpad);
	INSIST(dynbuf != NULL);
	if (!everything) {
		isc_buffer_clear(dynbuf);
		dynbuf = ISC_LIST_NEXT(dynbuf, link);
	}
	while (dynbuf != NULL) {
		next_dynbuf = ISC_LIST_NEXT(dynbuf, link);
		ISC_LIST_UNLINK(msg->scratchpad, dynbuf, link);
		isc_buffer_free(&dynbuf);
		dynbuf = next_dynbuf;
	}

	msgblock = ISC_LIST_HEAD(msg->rdatas);
	if (!everything && msgblock != NULL) {
		msgblock_reset(msgblock);
		msgblock = ISC_LIST_NEXT(msgblock, link);
	}
	while (msgblock != NULL) {
		next_msgblock = ISC_LIST_NEXT(msgblock, link);
		ISC_LIST_UNLINK(msg->rdatas, msgblock, link);
		msgblock_free(msg->mctx, msgblock, sizeof(dns_rdata_t));
		msgblock = next_msgblock;
	}

	/*
	 * rdatalists could be empty.
	 */

	msgblock = ISC_LIST_HEAD(msg->rdatalists);
	if (!everything && msgblock != NULL) {
		msgblock_reset(msgblock);
		msgblock = ISC_LIST_NEXT(msgblock, link);
	}
	while (msgblock != NULL) {
		next_msgblock = ISC_LIST_NEXT(msgblock, link);
		ISC_LIST_UNLINK(msg->rdatalists, msgblock, link);
		msgblock_free(msg->mctx, msgblock, sizeof(dns_rdatalist_t));
		msgblock = next_msgblock;
	}

	msgblock = ISC_LIST_HEAD(msg->offsets);
	if (!everything && msgblock != NULL) {
		msgblock_reset(msgblock);
		msgblock = ISC_LIST_NEXT(msgblock, link);
	}
	while (msgblock != NULL) {
		next_msgblock = ISC_LIST_NEXT(msgblock, link);
		ISC_LIST_UNLINK(msg->offsets, msgblock, link);
		msgblock_free(msg->mctx, msgblock, sizeof(dns_offsets_t));
		msgblock = next_msgblock;
	}

	if (msg->tsigkey != NULL) {
		dns_tsigkey_detach(&msg->tsigkey);
		msg->tsigkey = NULL;
	}

	if (msg->query.base != NULL) {
		if (msg->free_query != 0)
			isc_mem_put(msg->mctx, msg->query.base,
				    msg->query.length);
		msg->query.base = NULL;
		msg->query.length = 0;
	}

	if (msg->saved.base != NULL) {
		if (msg->free_saved != 0)
			isc_mem_put(msg->mctx, msg->saved.base,
				    msg->saved.length);
		msg->saved.base = NULL;
		msg->saved.length = 0;
	}

	/*
	 * cleanup the buffer cleanup list
	 */
	dynbuf = ISC_LIST_HEAD(msg->cleanup);
	while (dynbuf != NULL) {
		next_dynbuf = ISC_LIST_NEXT(dynbuf, link);
		ISC_LIST_UNLINK(msg->cleanup, dynbuf, link);
		isc_buffer_free(&dynbuf);
		dynbuf = next_dynbuf;
	}

	/*
	 * Set other bits to normal default values.
	 */
	if (!everything)
		msginit(msg);

	ENSURE(isc_mempool_getallocated(msg->namepool) == 0);
	ENSURE(isc_mempool_getallocated(msg->rdspool) == 0);
}

static unsigned int
spacefortsig(dns_tsigkey_t *key, int otherlen) {
	isc_region_t r1, r2;
	unsigned int x;
	isc_result_t result;

	/*
	 * The space required for an TSIG record is:
	 *
	 *	n1 bytes for the name
	 *	2 bytes for the type
	 *	2 bytes for the class
	 *	4 bytes for the ttl
	 *	2 bytes for the rdlength
	 *	n2 bytes for the algorithm name
	 *	6 bytes for the time signed
	 *	2 bytes for the fudge
	 *	2 bytes for the MAC size
	 *	x bytes for the MAC
	 *	2 bytes for the original id
	 *	2 bytes for the error
	 *	2 bytes for the other data length
	 *	y bytes for the other data (at most)
	 * ---------------------------------
	 *     26 + n1 + n2 + x + y bytes
	 */

	dns_name_toregion(&key->name, &r1);
	dns_name_toregion(key->algorithm, &r2);
	if (key->key == NULL)
		x = 0;
	else {
		result = dst_key_sigsize(key->key, &x);
		if (result != ISC_R_SUCCESS)
			x = 0;
	}
	return (26 + r1.length + r2.length + x + otherlen);
}

isc_result_t
dns_message_create(isc_mem_t *mctx, unsigned int intent, dns_message_t **msgp)
{
	dns_message_t *m;
	isc_result_t result;
	isc_buffer_t *dynbuf;
	unsigned int i;

	REQUIRE(mctx != NULL);
	REQUIRE(msgp != NULL);
	REQUIRE(*msgp == NULL);
	REQUIRE(intent == DNS_MESSAGE_INTENTPARSE
		|| intent == DNS_MESSAGE_INTENTRENDER);

	m = isc_mem_get(mctx, sizeof(dns_message_t));
	if (m == NULL)
		return (ISC_R_NOMEMORY);

	/*
	 * No allocations until further notice.  Just initialize all lists
	 * and other members that are freed in the cleanup phase here.
	 */

	m->magic = DNS_MESSAGE_MAGIC;
	m->from_to_wire = intent;
	msginit(m);

	for (i = 0; i < DNS_SECTION_MAX; i++)
		ISC_LIST_INIT(m->sections[i]);
	m->mctx = mctx;

	ISC_LIST_INIT(m->scratchpad);
	ISC_LIST_INIT(m->cleanup);
	m->namepool = NULL;
	m->rdspool = NULL;
	ISC_LIST_INIT(m->rdatas);
	ISC_LIST_INIT(m->rdatalists);
	ISC_LIST_INIT(m->offsets);
	ISC_LIST_INIT(m->freerdata);
	ISC_LIST_INIT(m->freerdatalist);

	/*
	 * Ok, it is safe to allocate (and then "goto cleanup" if failure)
	 */

	result = isc_mempool_create(m->mctx, sizeof(dns_name_t), &m->namepool);
	if (result != ISC_R_SUCCESS)
		goto cleanup;
	isc_mempool_setfreemax(m->namepool, NAME_COUNT);
	isc_mempool_setname(m->namepool, "msg:names");

	result = isc_mempool_create(m->mctx, sizeof(dns_rdataset_t),
				    &m->rdspool);
	if (result != ISC_R_SUCCESS)
		goto cleanup;
	isc_mempool_setfreemax(m->rdspool, NAME_COUNT);
	isc_mempool_setname(m->rdspool, "msg:rdataset");

	dynbuf = NULL;
	result = isc_buffer_allocate(mctx, &dynbuf, SCRATCHPAD_SIZE);
	if (result != ISC_R_SUCCESS)
		goto cleanup;
	ISC_LIST_APPEND(m->scratchpad, dynbuf, link);

	m->cctx = NULL;

	*msgp = m;
	return (ISC_R_SUCCESS);

	/*
	 * Cleanup for error returns.
	 */
 cleanup:
	dynbuf = ISC_LIST_HEAD(m->scratchpad);
	if (dynbuf != NULL) {
		ISC_LIST_UNLINK(m->scratchpad, dynbuf, link);
		isc_buffer_free(&dynbuf);
	}
	if (m->namepool != NULL)
		isc_mempool_destroy(&m->namepool);
	if (m->rdspool != NULL)
		isc_mempool_destroy(&m->rdspool);
	m->magic = 0;
	isc_mem_put(mctx, m, sizeof(dns_message_t));

	return (ISC_R_NOMEMORY);
}

void
dns_message_reset(dns_message_t *msg, unsigned int intent) {
	REQUIRE(DNS_MESSAGE_VALID(msg));
	REQUIRE(intent == DNS_MESSAGE_INTENTPARSE
		|| intent == DNS_MESSAGE_INTENTRENDER);

	msgreset(msg, ISC_FALSE);
	msg->from_to_wire = intent;
}

void
dns_message_destroy(dns_message_t **msgp) {
	dns_message_t *msg;

	REQUIRE(msgp != NULL);
	REQUIRE(DNS_MESSAGE_VALID(*msgp));

	msg = *msgp;
	*msgp = NULL;

	msgreset(msg, ISC_TRUE);
	isc_mempool_destroy(&msg->namepool);
	isc_mempool_destroy(&msg->rdspool);
	msg->magic = 0;
	isc_mem_put(msg->mctx, msg, sizeof(dns_message_t));
}

static isc_result_t
findname(dns_name_t **foundname, dns_name_t *target,
	 dns_namelist_t *section)
{
	dns_name_t *curr;

	for (curr = ISC_LIST_TAIL(*section);
	     curr != NULL;
	     curr = ISC_LIST_PREV(curr, link)) {
		if (dns_name_equal(curr, target)) {
			if (foundname != NULL)
				*foundname = curr;
			return (ISC_R_SUCCESS);
		}
	}

	return (ISC_R_NOTFOUND);
}

isc_result_t
dns_message_findtype(dns_name_t *name, dns_rdatatype_t type,
		     dns_rdatatype_t covers, dns_rdataset_t **rdataset)
{
	dns_rdataset_t *curr;

	if (rdataset != NULL) {
		REQUIRE(*rdataset == NULL);
	}

	for (curr = ISC_LIST_TAIL(name->list);
	     curr != NULL;
	     curr = ISC_LIST_PREV(curr, link)) {
		if (curr->type == type && curr->covers == covers) {
			if (rdataset != NULL)
				*rdataset = curr;
			return (ISC_R_SUCCESS);
		}
	}

	return (ISC_R_NOTFOUND);
}

/*
 * Read a name from buffer "source".
 */
static isc_result_t
getname(dns_name_t *name, isc_buffer_t *source, dns_message_t *msg,
	dns_decompress_t *dctx)
{
	isc_buffer_t *scratch;
	isc_result_t result;
	unsigned int tries;

	scratch = currentbuffer(msg);

	/*
	 * First try:  use current buffer.
	 * Second try:  allocate a new buffer and use that.
	 */
	tries = 0;
	while (tries < 2) {
		result = dns_name_fromwire(name, source, dctx, ISC_FALSE,
					   scratch);

		if (result == ISC_R_NOSPACE) {
			tries++;

			result = newbuffer(msg, SCRATCHPAD_SIZE);
			if (result != ISC_R_SUCCESS)
				return (result);

			scratch = currentbuffer(msg);
			dns_name_reset(name);
		} else {
			return (result);
		}
	}

	INSIST(0);  /* Cannot get here... */
	return (ISC_R_UNEXPECTED);
}

static isc_result_t
getrdata(isc_buffer_t *source, dns_message_t *msg, dns_decompress_t *dctx,
	 dns_rdataclass_t rdclass, dns_rdatatype_t rdtype,
	 unsigned int rdatalen, dns_rdata_t *rdata)
{
	isc_buffer_t *scratch;
	isc_result_t result;
	unsigned int tries;
	unsigned int trysize;

	scratch = currentbuffer(msg);

	isc_buffer_setactive(source, rdatalen);

	/*
	 * First try:  use current buffer.
	 * Second try:  allocate a new buffer of size
	 *     max(SCRATCHPAD_SIZE, 2 * compressed_rdatalen)
	 *     (the data will fit if it was not more than 50% compressed)
	 * Subsequent tries: double buffer size on each try.
	 */
	tries = 0;
	trysize = 0;
	/* XXX possibly change this to a while (tries < 2) loop */
	for (;;) {
		result = dns_rdata_fromwire(rdata, rdclass, rdtype,
					    source, dctx, 0,
					    scratch);

		if (result == ISC_R_NOSPACE) {
			if (tries == 0) {
				trysize = 2 * rdatalen;
				if (trysize < SCRATCHPAD_SIZE)
					trysize = SCRATCHPAD_SIZE;
			} else {
				INSIST(trysize != 0);
				if (trysize >= 65535)
					return (ISC_R_NOSPACE);
					/* XXX DNS_R_RRTOOLONG? */
				trysize *= 2;
			}
			tries++;
			result = newbuffer(msg, trysize);
			if (result != ISC_R_SUCCESS)
				return (result);

			scratch = currentbuffer(msg);
		} else {
			return (result);
		}
	}
}

#define DO_FORMERR					\
	do {						\
		if (best_effort)			\
			seen_problem = ISC_TRUE;	\
		else {					\
			result = DNS_R_FORMERR;		\
			goto cleanup;			\
		}					\
	} while (0)

static isc_result_t
getquestions(isc_buffer_t *source, dns_message_t *msg, dns_decompress_t *dctx,
	     unsigned int options)
{
	isc_region_t r;
	unsigned int count;
	dns_name_t *name;
	dns_name_t *name2;
	dns_offsets_t *offsets;
	dns_rdataset_t *rdataset;
	dns_rdatalist_t *rdatalist;
	isc_result_t result;
	dns_rdatatype_t rdtype;
	dns_rdataclass_t rdclass;
	dns_namelist_t *section;
	isc_boolean_t free_name;
	isc_boolean_t best_effort;
	isc_boolean_t seen_problem;

	section = &msg->sections[DNS_SECTION_QUESTION];

	best_effort = ISC_TF(options & DNS_MESSAGEPARSE_BESTEFFORT);
	seen_problem = ISC_FALSE;

	name = NULL;
	rdataset = NULL;
	rdatalist = NULL;

	for (count = 0; count < msg->counts[DNS_SECTION_QUESTION]; count++) {
		name = isc_mempool_get(msg->namepool);
		if (name == NULL)
			return (ISC_R_NOMEMORY);
		free_name = ISC_TRUE;
		
		offsets = newoffsets(msg);
		if (offsets == NULL) {
			result = ISC_R_NOMEMORY;
			goto cleanup;
		}
		dns_name_init(name, *offsets);

		/*
		 * Parse the name out of this packet.
		 */
		isc_buffer_remainingregion(source, &r);
		isc_buffer_setactive(source, r.length);
		result = getname(name, source, msg, dctx);
		if (result != ISC_R_SUCCESS)
			goto cleanup;

		/*
		 * Run through the section, looking to see if this name
		 * is already there.  If it is found, put back the allocated
		 * name since we no longer need it, and set our name pointer
		 * to point to the name we found.
		 */
		result = findname(&name2, name, section);

		/*
		 * If it is the first name in the section, accept it.
		 *
		 * If it is not, but is not the same as the name already
		 * in the question section, append to the section.  Note that
		 * here in the question section this is illegal, so return
		 * FORMERR.  In the future, check the opcode to see if
		 * this should be legal or not.  In either case we no longer
		 * need this name pointer.
		 */
		if (result != ISC_R_SUCCESS) {
			if (!ISC_LIST_EMPTY(*section))
				DO_FORMERR;
			ISC_LIST_APPEND(*section, name, link);
			free_name = ISC_FALSE;
		} else {
			isc_mempool_put(msg->namepool, name);
			name = name2;
			name2 = NULL;
			free_name = ISC_FALSE;
		}

		/*
		 * Get type and class.
		 */
		isc_buffer_remainingregion(source, &r);
		if (r.length < 4) {
			result = ISC_R_UNEXPECTEDEND;
			goto cleanup;
		}
		rdtype = isc_buffer_getuint16(source);
		rdclass = isc_buffer_getuint16(source);

		/*
		 * If this class is different than the one we already read,
		 * this is an error.
		 */
		if (msg->state == DNS_SECTION_ANY) {
			msg->state = DNS_SECTION_QUESTION;
			msg->rdclass = rdclass;
		} else if (msg->rdclass != rdclass)
			DO_FORMERR;

		/*
		 * Can't ask the same question twice.
		 */
		result = dns_message_findtype(name, rdtype, 0, NULL);
		if (result == ISC_R_SUCCESS)
			DO_FORMERR;

		/*
		 * Allocate a new rdatalist.
		 */
		rdatalist = newrdatalist(msg);
		if (rdatalist == NULL) {
			result = ISC_R_NOMEMORY;
			goto cleanup;
		}
		rdataset =  isc_mempool_get(msg->rdspool);
		if (rdataset == NULL) {
			result = ISC_R_NOMEMORY;
			goto cleanup;
		}

		/*
		 * Convert rdatalist to rdataset, and attach the latter to
		 * the name.
		 */
		rdatalist->type = rdtype;
		rdatalist->covers = 0;
		rdatalist->rdclass = rdclass;
		rdatalist->ttl = 0;