[LEDE-DEV] [PATCH mdns 1/2] Don't use _services._dns-sd._tcp.local

[Rafał Miłecki]

From: Rafał Miłecki <rafal at milecki.pl>

It seems mdns(d) was trying to support queries for two records with
following names:
1) _services._dns-sd._udp.local
2) _services._dns-sd._tcp.local

According to the RFC 6763 Section 9 only the first one should be used
and response PTR records should include services of both protocols: UDP
and TCP.

This fixes discovering TCP services as in practice no other software was
sending queries with _services._dns-sd._tcp.local.

Signed-off-by: Rafał Miłecki <rafal at milecki.pl>
---
 dns.c     |  4 +---
 service.c | 15 +++------------
 service.h |  3 +--
 3 files changed, 5 insertions(+), 17 deletions(-)

diff --git a/dns.c b/dns.c
index 550befc..91434f2 100644
--- a/dns.c
+++ b/dns.c
@@ -368,9 +368,7 @@ parse_question(struct interface *iface, char *name, struct dns_question *q)
 
 	case TYPE_PTR:
 		if (!strcmp(name, sdudp))
-			service_announce_services(iface, 0, announce_ttl);
-		else if (!strcmp(name, sdtcp))
-			service_announce_services(iface, 1, announce_ttl);
+			service_announce_services(iface, announce_ttl);
 		service_reply(iface, name, announce_ttl);
 		break;
 
diff --git a/service.c b/service.c
index e375fce..993e7cf 100644
--- a/service.c
+++ b/service.c
@@ -66,7 +66,6 @@ service_update(struct vlist_tree *tree, struct vlist_node *node_new,
 static struct blob_buf b;
 static VLIST_TREE(services, avl_strcmp, service_update, false, false);
 char *sdudp =  "_services._dns-sd._udp.local";
-char *sdtcp =  "_services._dns-sd._tcp.local";
 static int service_init_announce;
 
 static const char *
@@ -155,23 +154,16 @@ service_reply(struct interface *iface, const char *match, int ttl)
 }
 
 void
-service_announce_services(struct interface *iface, int tcp, int ttl)
+service_announce_services(struct interface *iface, int ttl)
 {
 	struct service *s;
 
 	vlist_for_each_element(&services, s, node) {
-		if (!strstr(s->service, "._tcp") && tcp)
-			continue;
-		if (!strstr(s->service, "._udp") && !tcp)
-			continue;
 		s->t = 0;
 		if (ttl) {
 			dns_init_answer();
 			service_add_ptr(s->service, ttl);
-			if (tcp)
-				dns_send_answer(iface, sdtcp);
-			else
-				dns_send_answer(iface, sdudp);
+			dns_send_answer(iface, sdudp);
 		}
 		service_reply_single(iface, s, ttl, 0);
 	}
@@ -180,8 +172,7 @@ service_announce_services(struct interface *iface, int tcp, int ttl)
 void
 service_announce(struct interface *iface, int ttl)
 {
-	service_announce_services(iface, 0, ttl);
-	service_announce_services(iface, 1, ttl);
+	service_announce_services(iface, ttl);
 }
 
 static void
diff --git a/service.h b/service.h
index 901bcbd..78ee854 100644
--- a/service.h
+++ b/service.h
@@ -15,11 +15,10 @@
 #define _SERVICE_H__
 
 extern char *sdudp;
-extern char *sdtcp;
 extern void service_init(int announce);
 extern void service_cleanup(void);
 extern void service_announce(struct interface *iface, int ttl);
 extern void service_reply(struct interface *iface, const char *match, int ttl);
-extern void service_announce_services(struct interface *iface, int tcp, int ttl);
+extern void service_announce_services(struct interface *iface, int ttl);
 
 #endif
-- 
2.11.0