From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Wed, 8 Nov 2023 12:37:04 +0000 (+0900)
Subject: resolve/mdns: silently ignore Known-Answers only packets
X-Git-Tag: v255-rc2~74^2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F29927%2Fhead;p=thirdparty%2Fsystemd.git

resolve/mdns: silently ignore Known-Answers only packets
---

diff --git a/src/resolve/resolved-mdns.c b/src/resolve/resolved-mdns.c
index 11e3b141253..b63073af7fd 100644
--- a/src/resolve/resolved-mdns.c
+++ b/src/resolve/resolved-mdns.c
@@ -254,8 +254,9 @@ 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: Support Known-Answers only packets gracefully. */
         if (dns_question_size(p->question) <= 0)
-                return log_debug_errno(SYNTHETIC_ERRNO(EBADMSG), "Received mDNS query without question, ignoring.");
+                return 0;
 
         unicast_reply = mdns_should_reply_using_unicast(p);
         if (unicast_reply && !sender_on_local_subnet(s, p)) {