Fix problems with DNAME chain processing in the resolver, and with

retrievals of DNAMEs from the cache.  (Changes 516, 517, and 518).

CHANGES

+ 518.	[bug]		The resolver did not realize that a DNAME which was
+			"the answer" to the client's query was "the answer",
+			and such queries would fail.
+
+ 517.	[bug]		The resolver's DNAME code would trigger an assertion
+			if there was more than one DNAME in the chain.
+
+ 516.	[bug]		Cache lookups which had a NULL node pointer, e.g.
+			those by dns_view_find(), and which would match a
+			DNAME, would trigger an INSIST(!search.need_cleanup)
+			assertion.
+
  515.	[bug]		The ssu table was not beinge attached / detached
 			by dns_zone_[sg]etssutable.  [RT#397]
 

lib/dns/rbtdb.c

@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: rbtdb.c,v 1.126 2000/09/11 16:48:25 halley Exp $ */
+/* $Id: rbtdb.c,v 1.127 2000/10/13 18:55:10 halley Exp $ */
 
 /*
  * Principal Author: Bob Halley
@@ -2478,7 +2478,20 @@ cache_find(dns_db_t *db, dns_name_t *name, dns_dbversion_t *version,
  tree_exit:
 	RWUNLOCK(&search.rbtdb->tree_lock, isc_rwlocktype_read);
 
-	INSIST(!search.need_cleanup);
+	/*
+	 * If we found a zonecut but aren't going to use it, we have to
+	 * let go of it.
+	 */
+	if (search.need_cleanup) {
+		node = search.zonecut;
+
+		LOCK(&(search.rbtdb->node_locks[node->locknum].lock));
+		INSIST(node->references > 0);
+		node->references--;
+		if (node->references == 0)
+			no_references(search.rbtdb, node, 0);
+		UNLOCK(&(search.rbtdb->node_locks[node->locknum].lock));
+	}
 
 	dns_rbtnodechain_reset(&search.chain);
 

lib/dns/resolver.c

@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: resolver.c,v 1.171 2000/10/07 00:09:24 bwelling Exp $ */
+/* $Id: resolver.c,v 1.172 2000/10/13 18:55:11 halley Exp $ */
 
 #include <config.h>
 
@@ -3116,17 +3116,15 @@ dname_target(dns_rdataset_t *rdataset, dns_name_t *qname, dns_name_t *oname,
 {
 	isc_result_t result;
 	dns_rdata_t rdata;
-	dns_name_t *tname;
 	unsigned int nlabels, nbits;
 	int order;
 	dns_namereln_t namereln;
 	dns_rdata_dname_t dname;
+	dns_fixedname_t prefix;
 
 	/*
 	 * Get the target name of the DNAME.
 	 */
-	dns_fixedname_init(fixeddname);
-	tname = dns_fixedname_name(fixeddname);
 
 	result = dns_rdataset_first(rdataset);
 	if (result != ISC_R_SUCCESS)
@@ -3145,13 +3143,17 @@ dname_target(dns_rdataset_t *rdataset, dns_name_t *qname, dns_name_t *oname,
 		dns_rdata_freestruct(&dname);
 		return (DNS_R_FORMERR);
 	}
-	result = dns_name_split(qname, nlabels, nbits, tname, NULL);
+	dns_fixedname_init(&prefix);
+	result = dns_name_split(qname, nlabels, nbits,
+				dns_fixedname_name(&prefix), NULL);
 	if (result != ISC_R_SUCCESS) {
 		dns_rdata_freestruct(&dname);
 		return (result);
 	}
-
-	result = dns_name_concatenate(tname, &dname.dname, tname, NULL);
+	dns_fixedname_init(fixeddname);
+	result = dns_name_concatenate(dns_fixedname_name(&prefix),
+				      &dname.dname,
+				      dns_fixedname_name(fixeddname), NULL);
 	dns_rdata_freestruct(&dname);
 	return (result);
 }
@@ -3390,7 +3392,7 @@ answer_response(fetchctx_t *fctx) {
 	isc_boolean_t have_answer, found_cname, found_type;
 	unsigned int aflag;
 	dns_rdatatype_t type;
-	dns_fixedname_t dname;
+	dns_fixedname_t dname, fqname;
 
 	FCTXTRACE("answer_response");
 
@@ -3614,6 +3616,9 @@ answer_response(fetchctx_t *fctx) {
 						 * we're not chaining.
 						 */
 						INSIST(!external);
+						if (aflag ==
+						    DNS_RDATASETATTR_ANSWER)
+							have_answer = ISC_TRUE;
 						name->attributes |=
 							DNS_NAMEATTR_ANSWER;
 						rdataset->attributes |= aflag;
@@ -3629,11 +3634,30 @@ answer_response(fetchctx_t *fctx) {
 					 * DNAME chaining.
 					 */
 					if (want_chaining) {
+						/*
+						 * Copy the the dname into the
+						 * qname fixed name.
+						 *
+						 * Although we check for
+						 * failure of the concatenate
+						 * operation, in practice it
+						 * should never fail since
+						 * we already know that the
+						 * result fits in a fixedname.
+						 */
+						dns_fixedname_init(&fqname);
+						result = dns_name_concatenate(
+					          dns_fixedname_name(&dname),
+						  NULL,
+						  dns_fixedname_name(&fqname),
+						  NULL);
+						if (result != ISC_R_SUCCESS)
+							return (result);
 						chaining = ISC_TRUE;
 						rdataset->attributes |=
 						    DNS_RDATASETATTR_CHAINING;
 						qname = dns_fixedname_name(
-								   &dname);
+								   &fqname);
 					}
 				}
 			}