resolved: answer all mDNS questions found in packet

According to p5.3 of RFC6762 (Multicast DNS) one mDNS query message
can contain more than one question sections.

Generate answers for all found questions and put them to a reply
message.

diff --git a/src/resolve/resolved-mdns.c b/src/resolve/resolved-mdns.c
index a492937176d2ee1e83ae42c6a2c949f12445eac8..1cc1195717e7f371b5d8248532e92d624f767b74 100644 (file)
--- a/src/resolve/resolved-mdns.c
+++ b/src/resolve/resolved-mdns.c
@@ -69,7 +69,7 @@ eaddrinuse:
 }
 
 static int mdns_scope_process_query(DnsScope *s, DnsPacket *p) {
-        _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL;
+        _cleanup_(dns_answer_unrefp) DnsAnswer *full_answer = NULL;
         _cleanup_(dns_packet_unrefp) DnsPacket *reply = NULL;
         DnsResourceKey *key = NULL;
         bool tentative = false;
@@ -82,17 +82,24 @@ static int mdns_scope_process_query(DnsScope *s, DnsPacket *p) {
         if (r < 0)
                 return log_debug_errno(r, "Failed to extract resource records from incoming packet: %m");
 
-        /* TODO: there might be more than one question in mDNS queries. */
         assert_return((dns_question_size(p->question) > 0), -EINVAL);
-        key = p->question->keys[0];
 
-        r = dns_zone_lookup(&s->zone, key, 0, &answer, &soa, &tentative);
-        if (r < 0)
-                return log_debug_errno(r, "Failed to lookup key: %m");
-        if (r == 0)
+        DNS_QUESTION_FOREACH(key, p->question) {
+                _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL, *soa = NULL;
+
+                r = dns_zone_lookup(&s->zone, key, 0, &answer, &soa, &tentative);
+                if (r < 0)
+                        return log_debug_errno(r, "Failed to lookup key: %m");
+
+                r = dns_answer_extend(&full_answer, answer);
+                if (r < 0)
+                        return log_debug_errno(r, "Failed to extend answer: %m");
+        }
+
+        if (dns_answer_isempty(full_answer))
                 return 0;
 
-        r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, NULL, answer, NULL, false, &reply);
+        r = dns_scope_make_reply_packet(s, DNS_PACKET_ID(p), DNS_RCODE_SUCCESS, NULL, full_answer, NULL, false, &reply);
         if (r < 0)
                 return log_debug_errno(r, "Failed to build reply packet: %m");