From: Dmitry Rozhkov <dmitry.rozhkov@linux.intel.com>
Date: Fri, 29 Sep 2017 11:13:47 +0000 (+0300)
Subject: resolved: answer all mDNS questions found in packet
X-Git-Tag: v236~33^2~15
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=9c5e7b73f7340e64f831aba7e90b9265f049ca96;p=thirdparty%2Fsystemd.git

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 a492937176d..1cc1195717e 100644
--- 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");