message.c

bind 9.3结合mysql数据库

		ISC_LIST_INIT(rdatalist->rdata);

		dns_rdataset_init(rdataset);
		result = dns_rdatalist_tordataset(rdatalist, rdataset);
		if (result != ISC_R_SUCCESS)
			goto cleanup;

		rdataset->attributes |= DNS_RDATASETATTR_QUESTION;

		ISC_LIST_APPEND(name->list, rdataset, link);
		rdataset = NULL;
	}

	if (seen_problem)
		return (DNS_R_RECOVERABLE);
	return (ISC_R_SUCCESS);

 cleanup:
	if (rdataset != NULL) {
		INSIST(!dns_rdataset_isassociated(rdataset));
		isc_mempool_put(msg->rdspool, rdataset);
	}
#if 0
	if (rdatalist != NULL)
		isc_mempool_put(msg->rdlpool, rdatalist);
#endif
	if (free_name)
		isc_mempool_put(msg->namepool, name);

	return (result);
}

static isc_boolean_t
update(dns_section_t section, dns_rdataclass_t rdclass) {
	if (section == DNS_SECTION_PREREQUISITE)
		return (ISC_TF(rdclass == dns_rdataclass_any ||
			       rdclass == dns_rdataclass_none));
	if (section == DNS_SECTION_UPDATE)
		return (ISC_TF(rdclass == dns_rdataclass_any));
	return (ISC_FALSE);
}

static isc_result_t
getsection(isc_buffer_t *source, dns_message_t *msg, dns_decompress_t *dctx,
	   dns_section_t sectionid, unsigned int options)
{
	isc_region_t r;
	unsigned int count, rdatalen;
	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, covers;
	dns_rdataclass_t rdclass;
	dns_rdata_t *rdata;
	dns_ttl_t ttl;
	dns_namelist_t *section;
	isc_boolean_t free_name, free_rdataset;
	isc_boolean_t preserve_order, best_effort, seen_problem;
	isc_boolean_t issigzero;

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

	for (count = 0; count < msg->counts[sectionid]; count++) {
		int recstart = source->current;
		isc_boolean_t skip_name_search, skip_type_search;

		section = &msg->sections[sectionid];

		skip_name_search = ISC_FALSE;
		skip_type_search = ISC_FALSE;
		free_name = ISC_FALSE;
		free_rdataset = ISC_FALSE;

		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;

		/*
		 * Get type, class, ttl, and rdatalen.  Verify that at least
		 * rdatalen bytes remain.  (Some of this is deferred to
		 * later.)
		 */
		isc_buffer_remainingregion(source, &r);
		if (r.length < 2 + 2 + 4 + 2) {
			result = ISC_R_UNEXPECTEDEND;
			goto cleanup;
		}
		rdtype = isc_buffer_getuint16(source);
		rdclass = isc_buffer_getuint16(source);

		/*
		 * If there was no question section, we may not yet have
		 * established a class.  Do so now.
		 */
		if (msg->state == DNS_SECTION_ANY &&
		    rdtype != dns_rdatatype_opt &&	/* class is UDP SIZE */
		    rdtype != dns_rdatatype_tsig &&	/* class is ANY */
		    rdtype != dns_rdatatype_tkey) {	/* class is undefined */
			msg->rdclass = rdclass;
			msg->state = DNS_SECTION_QUESTION;
		}

		/*
		 * If this class is different than the one in the question
		 * section, bail.
		 */
		if (msg->opcode != dns_opcode_update
		    && rdtype != dns_rdatatype_tsig
		    && rdtype != dns_rdatatype_opt
		    && rdtype != dns_rdatatype_dnskey /* in a TKEY query */
		    && rdtype != dns_rdatatype_sig /* SIG(0) */
		    && rdtype != dns_rdatatype_tkey /* Win2000 TKEY */
		    && msg->rdclass != rdclass)
			DO_FORMERR;

		/*
		 * Special type handling for TSIG, OPT, and TKEY.
		 */
		if (rdtype == dns_rdatatype_tsig) {
			/*
			 * If it is a tsig, verify that it is in the
			 * additional data section.
			 */
			if (sectionid != DNS_SECTION_ADDITIONAL ||
			    rdclass != dns_rdataclass_any ||
			    count != msg->counts[sectionid]  - 1)
				DO_FORMERR;
			msg->sigstart = recstart;
			skip_name_search = ISC_TRUE;
			skip_type_search = ISC_TRUE;
		} else if (rdtype == dns_rdatatype_opt) {
			/*
			 * The name of an OPT record must be ".", it
			 * must be in the additional data section, and
			 * it must be the first OPT we've seen.
			 */
			if (!dns_name_equal(dns_rootname, name) ||
			    msg->opt != NULL)
				DO_FORMERR;
			skip_name_search = ISC_TRUE;
			skip_type_search = ISC_TRUE;
		} else if (rdtype == dns_rdatatype_tkey) {
			/*
			 * A TKEY must be in the additional section if this
			 * is a query, and the answer section if this is a
			 * response.  Unless it's a Win2000 client.
			 *
			 * Its class is ignored.
			 */
			dns_section_t tkeysection;

			if ((msg->flags & DNS_MESSAGEFLAG_QR) == 0)
				tkeysection = DNS_SECTION_ADDITIONAL;
			else
				tkeysection = DNS_SECTION_ANSWER;
			if (sectionid != tkeysection &&
			    sectionid != DNS_SECTION_ANSWER)
				DO_FORMERR;
		}

		/*
		 * ... now get ttl and rdatalen, and check buffer.
		 */
		ttl = isc_buffer_getuint32(source);
		rdatalen = isc_buffer_getuint16(source);
		r.length -= (2 + 2 + 4 + 2);
		if (r.length < rdatalen) {
			result = ISC_R_UNEXPECTEDEND;
			goto cleanup;
		}

		/*
		 * Read the rdata from the wire format.  Interpret the
		 * rdata according to its actual class, even if it had a
		 * DynDNS meta-class in the packet (unless this is a TSIG).
		 * Then put the meta-class back into the finished rdata.
		 */
		rdata = newrdata(msg);
		if (rdata == NULL) {
			result = ISC_R_NOMEMORY;
			goto cleanup;
		}
		if (msg->opcode == dns_opcode_update &&
		    update(sectionid, rdclass)) {
			if (rdatalen != 0) {
				result = DNS_R_FORMERR;
				goto cleanup;
			}
			/*
			 * When the rdata is empty, the data pointer is
			 * never dereferenced, but it must still be non-NULL. 
			 * Casting 1 rather than "" avoids warnings about
			 * discarding the const attribute of a string,
			 * for compilers that would warn about such things.
			 */
			rdata->data = (unsigned char *)1;
			rdata->length = 0;
			rdata->rdclass = rdclass;
			rdata->type = rdtype;
			rdata->flags = DNS_RDATA_UPDATE;
			result = ISC_R_SUCCESS;
		} else if (rdtype == dns_rdatatype_tsig)
			result = getrdata(source, msg, dctx, rdclass,
					  rdtype, rdatalen, rdata);
		else
			result = getrdata(source, msg, dctx, msg->rdclass,
					  rdtype, rdatalen, rdata);
		if (result != ISC_R_SUCCESS)
			goto cleanup;
		rdata->rdclass = rdclass;
		issigzero = ISC_FALSE;
		if (rdtype == dns_rdatatype_rrsig  &&
		    rdata->flags == 0) {
			covers = dns_rdata_covers(rdata);
			if (covers == 0)
				DO_FORMERR;
		} else if (rdtype == dns_rdatatype_sig /* SIG(0) */ &&
			   rdata->flags == 0) {
			covers = dns_rdata_covers(rdata);
			if (covers == 0) {
				if (sectionid != DNS_SECTION_ADDITIONAL ||
				    count != msg->counts[sectionid]  - 1)
					DO_FORMERR;
				msg->sigstart = recstart;
				skip_name_search = ISC_TRUE;
				skip_type_search = ISC_TRUE;
				issigzero = ISC_TRUE;
			}
		} else
			covers = 0;

		/*
		 * If we are doing a dynamic update or this is a meta-type,
		 * don't bother searching for a name, just append this one
		 * to the end of the message.
		 */
		if (preserve_order || msg->opcode == dns_opcode_update ||
		    skip_name_search) {
			if (rdtype != dns_rdatatype_opt &&
			    rdtype != dns_rdatatype_tsig &&
			    !issigzero)
			{
				ISC_LIST_APPEND(*section, name, link);
				free_name = ISC_FALSE;
			}
		} else {
			/*
			 * 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 a new name, append to the section.
			 */
			if (result == ISC_R_SUCCESS) {
				isc_mempool_put(msg->namepool, name);
				name = name2;
			} else {
				ISC_LIST_APPEND(*section, name, link);
			}
			free_name = ISC_FALSE;
		}

		/*
		 * Search name for the particular type and class.
		 * Skip this stage if in update mode or this is a meta-type.
		 */
		if (preserve_order || msg->opcode == dns_opcode_update ||
		    skip_type_search)
			result = ISC_R_NOTFOUND;
		else {
			/*
			 * If this is a type that can only occur in
			 * the question section, fail.
			 */
			if (dns_rdatatype_questiononly(rdtype))
				DO_FORMERR;

			rdataset = NULL;
			result = dns_message_findtype(name, rdtype, covers,
						      &rdataset);
		}

		/*
		 * If we found an rdataset that matches, we need to
		 * append this rdata to that set.  If we did not, we need
		 * to create a new rdatalist, store the important bits there,
		 * convert it to an rdataset, and link the latter to the name.
		 * Yuck.  When appending, make certain that the type isn't
		 * a singleton type, such as SOA or CNAME.
		 *
		 * Note that this check will be bypassed when preserving order,
		 * the opcode is an update, or the type search is skipped.
		 */
		if (result == ISC_R_SUCCESS) {
			if (dns_rdatatype_issingleton(rdtype))
				DO_FORMERR;
		}

		if (result == ISC_R_NOTFOUND) {
			rdataset = isc_mempool_get(msg->rdspool);
			if (rdataset == NULL) {
				result = ISC_R_NOMEMORY;
				goto cleanup;
			}
			free_rdataset = ISC_TRUE;

			rdatalist = newrdatalist(msg);
			if (rdatalist == NULL) {
				result = ISC_R_NOMEMORY;
				goto cleanup;
			}

			rdatalist->type = rdtype;
			rdatalist->covers = covers;
			rdatalist->rdclass = rdclass;
			rdatalist->ttl = ttl;
			ISC_LIST_INIT(rdatalist->rdata);

			dns_rdataset_init(rdataset);
			RUNTIME_CHECK(dns_rdatalist_tordataset(rdatalist,
							       rdataset)
				      == ISC_R_SUCCESS);

			if (rdtype != dns_rdatatype_opt && 
			    rdtype != dns_rdatatype_tsig &&
			    !issigzero)
			{
				ISC_LIST_APPEND(name->list, rdataset, link);
				free_rdataset = ISC_FALSE;
			}
		}

		/*
		 * Minimize TTLs.
		 *
		 * Section 5.2 of RFC 2181 says we should drop
		 * nonauthoritative rrsets where the TTLs differ, but we
		 * currently treat them the as if they were authoritative and
		 * minimize them.
		 */
		if (ttl != rdataset->ttl) {
			rdataset->attributes |= DNS_RDATASETATTR_TTLADJUSTED;
			if (ttl < rdataset->ttl)
				rdataset->ttl = ttl;
		}

		/*
		 * XXXMLG Perform a totally ugly hack here to pull
		 * the rdatalist out of the private field in the rdataset,
		 * and append this rdata to the rdatalist's linked list
		 * of rdata.
		 */
		rdatalist = (dns_rdatalist_t *)(rdataset->private1);

		ISC_LIST_APPEND(rdatalist->rdata, rdata, link);

		/*
		 * If this is an OPT record, remember it.  Also, set
		 * the extended rcode.  Note that msg->opt will only be set
		 * if best-effort parsing is enabled.
		 */
		if (rdtype == dns_rdatatype_opt && msg->opt == NULL) {
			dns_rcode_t ercode;

			msg->opt = rdataset;
			rdataset = NULL;
			free_rdataset = ISC_FALSE;
			ercode = (dns_rcode_t)
				((msg->opt->ttl & DNS_MESSAGE_EDNSRCODE_MASK)
				 >> 20);
			msg->rcode |= ercode;
			isc_mempool_put(msg->namepool, name);
			free_name = ISC_FALSE;
		}

		/*
		 * If this is an SIG(0) or TSIG record, remember it.  Note
		 * that msg->sig0 or msg->tsig will only be set if best-effort
		 * parsing is enabled.
		 */
		if (issigzero && msg->sig0 == NULL) {
			msg->sig0 = rdataset;
			msg->sig0name = name;
			rdataset = NULL;
			free_rdataset = ISC_FALSE;
			free_name = ISC_FALSE;
		} else if (rdtype == dns_rdatatype_tsig && msg->tsig == NULL) {
			msg->tsig = rdataset;
			msg->tsigname = name;
			rdataset = NULL;
			free_rdataset = ISC_FALSE;
			free_name = ISC_FALSE;
		}

		INSIST(free_name == ISC_FALSE);
		INSIST(free_rdataset == ISC_FALSE);
	}

	if (seen_problem)
		return (DNS_R_RECOVERABLE);
	return (ISC_R_SUCCESS);

 cleanup:
	if (free_name)
		isc_mempool_put(msg->namepool, name);
	if (free_rdataset)
		isc_mempool_put(msg->rdspool, rdataset);

	return (result);
}

isc_result_t
dns_message_parse(dns_message_t *msg, isc_buffer_t *source,
		  unsigned int options)
{
	isc_region_t r;
	dns_decompress_t dctx;
	isc_result_t ret;
	isc_uint16_t tmpflags;
	isc_buffer_t origsource;
	isc_boolean_t seen_problem;
	isc_boolean_t ignore_tc;

	REQUIRE(DNS_MESSAGE_VALID(msg));
	REQUIRE(source != NULL);
	REQUIRE(msg->from_to_wire == DNS_MESSAGE_INTENTPARSE);

	seen_problem = ISC_FALSE;
	ignore_tc = ISC_TF(options & DNS_MESSAGEPARSE_IGNORETRUNCATION);

	origsource = *source;

	msg->header_ok = 0;
	msg->question_ok = 0;

	isc_buffer_remainingregion(source, &r);
	if (r.length < DNS_MESSAGE_HEADERLEN)
		return (ISC_R_UNEXPECTEDEND);

	msg->id = isc_buffer_getuint16(source);
	tmpflags = isc_buffer_getuint16(source);
	msg->opcode = ((tmpflags & DNS_MESSAGE_OPCODE_MASK)
		       >> DNS_MESSAGE_OPCODE_SHIFT);
	msg->rcode = (dns_rcode_t)(tmpflags & DNS_MESSAGE_RCODE_MASK);
	msg->flags = (tmpflags & DNS_MESSAGE_FLAG_MASK);
	msg->counts[DNS_SECTION_QUESTION] = isc_buffer_getuint16(source);
	msg->counts[DNS_SECTION_ANSWER] = isc_buffer_getuint16(source);
	msg->counts[DNS_SECTION_AUTHORITY] = isc_buffer_getuint16(source);
	msg->counts[DNS_SECTION_ADDITIONAL] = isc_buffer_getuint16(source);

	msg->header_ok = 1;

	/*
	 * -1 means no EDNS.
	 */
	dns_decompress_init(&dctx, -1, DNS_DECOMPRESS_ANY);

	dns_decompress_setmethods(&dctx, DNS_COMPRESS_GLOBAL14);

	ret = getquestions(source, msg, &dctx, options);
	if (ret == ISC_R_UNEXPECTEDEND && ignore_tc)
		goto truncated;
	if (ret == DNS_R_RECOVERABLE) {
		seen_problem = ISC_TRUE;
		ret = ISC_R_SUCCESS;
	}
	if (ret != ISC_R_SUCCESS)
		return (ret);
	msg->question_ok = 1;

	ret = getsection(source, msg, &dctx, DNS_SECTION_ANSWER, options);
	if (ret == ISC_R_UNEXPECTEDEND && ignore_tc)
		goto truncated;
	if (ret == DNS_R_RECOVERABLE) {
		seen_problem = ISC_TRUE;
		ret = ISC_R_SUCCESS;
	}
	if (ret != ISC_R_SUCCESS)
		return (ret);

	ret = getsection(source, msg, &dctx, DNS_SECTION_AUTHORITY, options);
	if (ret == ISC_R_UNEXPECTEDEND && ignore_tc)
		goto truncated;
	if (ret == DNS_R_RECOVERABLE) {
		seen_problem = ISC_TRUE;
		ret = ISC_R_SUCCESS;
	}
	if (ret != ISC_R_SUCCESS)
		return (ret);

	ret = getsection(source, msg, &dctx, DNS_SECTION_ADDITIONAL, options);
	if (ret == ISC_R_UNEXPECTEDEND && ignore_tc)
		goto truncated;
	if (ret == DNS_R_RECOVERABLE) {
		seen_problem = ISC_TRUE;
		ret = ISC_R_SUCCESS;
	}
	if (ret != ISC_R_SUCCESS)
		return (ret);

	isc_buffer_remainingregion(source, &r);
	if (r.length != 0) {
		isc_log_write(dns_lctx, ISC_LOGCATEGORY_GENERAL,