commit ca0bd2cc2338b9c27d2a80c90862e1eb4d69dd7e
author Jukka Rissanen <jukka.rissanen@nordicsemi.no> Mon Sep 23 15:38:36 2024 +0300
committer Mahesh Mahadevan <mahesh.mahadevan@nxp.com> Wed Sep 25 13:52:15 2024 -0500
tree 5d95bc32eb5e0cecfa74d39c2202e4dd2244986c
parent 6db9cbc49912c99be9e83737f6da2a6b640301dc

net: mdns: Discard the message if query count is 0

As described in RFC 6804 ch. 2, if query count is 0, discard
the message silently.

Signed-off-by: Jukka Rissanen <jukka.rissanen@nordicsemi.no>

subsys/net/lib/dns/dns_pack.c

diff --git a/subsys/net/lib/dns/dns_pack.c b/subsys/net/lib/dns/dns_pack.c
index 3362828..34b3651 100644
--- a/subsys/net/lib/dns/dns_pack.c
+++ b/subsys/net/lib/dns/dns_pack.c
@@ -449,7 +449,8 @@
 
 	qdcount = dns_unpack_header_qdcount(dns_header);
 	if (qdcount < 1) {
-		return -EINVAL;
+		/* Discard the message if query count is 0. RFC 6804 ch. 2 */
+		return -ENOENT;
 	}
 
 	if (src_id) {

subsys/net/lib/dns/mdns_responder.c

diff --git a/subsys/net/lib/dns/mdns_responder.c b/subsys/net/lib/dns/mdns_responder.c
index c065580..f9a3b75 100644
--- a/subsys/net/lib/dns/mdns_responder.c
+++ b/subsys/net/lib/dns/mdns_responder.c
@@ -533,7 +533,6 @@
 
 	ret = mdns_unpack_query_header(&dns_msg, NULL);
 	if (ret < 0) {
-		ret = -EINVAL;
 		goto quit;
 	}
 
@@ -670,7 +669,7 @@
 	ARG_UNUSED(my_ctx);
 
 	ret = dns_read(sock, dns_data, len, addr, addrlen);
-	if (ret < 0 && ret != -EINVAL) {
+	if (ret < 0 && ret != -EINVAL && ret != -ENOENT) {
 		NET_DBG("%s read failed (%d)", "mDNS", ret);
 	}