Fix bug#307: 0x20 fallback outstanding query count, together with rec_lame,

and canonical rrset comparison.


git-svn-id: file:///svn/unbound/trunk@2097 be551aaa-1e26-0410-a405-d3ace91eadb9

doc/Changelog

@@ -7,6 +7,11 @@
 	  no more double include.
 	- More strict scrubber (Thanks to George Barwood for the idea):
 	  NS set must be pertinent to the query (qname subdomain nsname).
+	- Fix bug#307: In 0x20 backoff fix fallback so the number of 
+	  outstanding queries does not become -1 and block the request.
+	  Fixed handling of recursion-lame in combination with 0x20 fallback.
+	  Fix so RRsets are compared canonicalized and sorted if the immediate
+	  comparison fails, this makes it work around round-robin sites.
 
 23 April 2010: Wouter
 	- Squelch log message: sendto failed permission denied for

iterator/iter_utils.c

@@ -674,7 +674,7 @@ rrset_equal(struct ub_packed_rrset_key* k1, struct ub_packed_rrset_key* k2)
 }
 
 int 
-reply_equal(struct reply_info* p, struct reply_info* q)
+reply_equal(struct reply_info* p, struct reply_info* q, ldns_buffer* scratch)
 {
 	size_t i;
 	if(p->flags != q->flags ||
@@ -688,9 +688,30 @@ reply_equal(struct reply_info* p, struct reply_info* q)
 		p->rrset_count != q->rrset_count)
 		return 0;
 	for(i=0; i<p->rrset_count; i++) {
-		if(!rrset_equal(p->rrsets[i], q->rrsets[i]))
+		if(!rrset_equal(p->rrsets[i], q->rrsets[i])) {
+			/* fallback procedure: try to sort and canonicalize */
+			ldns_rr_list* pl, *ql;
+			pl = packed_rrset_to_rr_list(p->rrsets[i], scratch);
+			ql = packed_rrset_to_rr_list(q->rrsets[i], scratch);
+			if(!pl || !ql) {
+				ldns_rr_list_deep_free(pl);
+				ldns_rr_list_deep_free(ql);
 				return 0;
 			}
+			ldns_rr_list2canonical(pl);
+			ldns_rr_list2canonical(ql);
+			ldns_rr_list_sort(pl);
+			ldns_rr_list_sort(ql);
+			if(ldns_rr_list_compare(pl, ql) != 0) {
+				ldns_rr_list_deep_free(pl);
+				ldns_rr_list_deep_free(ql);
+				return 0;
+			}
+			ldns_rr_list_deep_free(pl);
+			ldns_rr_list_deep_free(ql);
+			continue;
+		}
+	}
 	return 1;
 }
 
@@ -792,3 +813,18 @@ iter_scrub_ds(struct dns_msg* msg, struct ub_packed_rrset_key* ns, uint8_t* z)
 		i++;
 	}
 }
+
+void iter_dec_attempts(struct delegpt* dp, int d)
+{
+	struct delegpt_addr* a;
+	for(a=dp->target_list; a; a = a->next_target) {
+		if(a->attempts >= OUTBOUND_MSG_RETRY) {
+			/* add back to result list */
+			a->next_result = dp->result_list;
+			dp->result_list = a;
+		}
+		if(a->attempts > d)
+			a->attempts -= d;
+		else a->attempts = 0;
+	}
+}

iterator/iter_utils.h

@@ -211,9 +211,10 @@ int iter_msg_from_zone(struct dns_msg* msg, struct delegpt* dp,
  * @param p: reply one. The reply has rrset data pointers in region.
  * 	Does not check rrset-IDs
  * @param q: reply two
+ * @param buf: scratch buffer.
  * @return if one and two are equal.
  */
-int reply_equal(struct reply_info* p, struct reply_info* q);
+int reply_equal(struct reply_info* p, struct reply_info* q, ldns_buffer* buf);
 
 /**
  * Store in-zone glue in seperate rrset cache entries for later last-resort
@@ -257,4 +258,11 @@ int iter_get_next_root(struct iter_hints* hints, struct iter_forwards* fwd,
 void iter_scrub_ds(struct dns_msg* msg, struct ub_packed_rrset_key* ns,
 	uint8_t* z);
 
+/**
+ * Remove query attempts from all available ips. For 0x20.
+ * @param dp: delegpt.
+ * @param d: decrease.
+ */
+void iter_dec_attempts(struct delegpt* dp, int d);
+
 #endif /* ITERATOR_ITER_UTILS_H */

iterator/iterator.c

@@ -1416,6 +1416,9 @@ processQueryTargets(struct module_qstate* qstate, struct iter_qstate* iq,
 				"match for %d wanted, done.", 
 				(int)iq->caps_server+1, (int)naddr*3);
 			iq->caps_fallback = 0;
+			iter_dec_attempts(iq->dp, 3); /* space for fallback */
+			iq->num_current_queries++; /* RespState decrements it*/
+			iq->referral_count++; /* make sure we don't loop */
 			iq->state = QUERY_RESP_STATE;
 			return 1;
 		}
@@ -2384,7 +2387,8 @@ process_response(struct module_qstate* qstate, struct iter_qstate* iq,
 			goto handle_it;
 		} else {
 			/* check if reply is the same, otherwise, fail */
-			if(!reply_equal(iq->response->rep, iq->caps_reply)) {
+			if(!reply_equal(iq->response->rep, iq->caps_reply,
+				qstate->env->scratch_buffer)) {
 				verbose(VERB_DETAIL, "Capsforid fallback: "
 					"getting different replies, failed");
 				outbound_list_remove(&iq->outlist, outbound);