Support PTR queries for a specific service

We should check if queried name starts with a _ to see if it is about a
specific service + domain.

Fixes: 70c66fbbcde86 ("Fix sending replies to PTR questions")
Reported-by: Cristian Morales Vega <cristian@samknows.com>
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

diff --git a/dns.c b/dns.c
index bccaa29525fdafde1de30060050b769ecc04b6a5..aadfdd8f6927806cbdb7108d81c1031559100308 100644 (file)
--- a/dns.c
+++ b/dns.c
@@ -378,15 +378,18 @@ parse_question(struct interface *iface, struct sockaddr *from, char *name, struc
                        dns_reply_a(iface, to, announce_ttl);
                        service_announce_services(iface, to, announce_ttl);
                } else {
                        dns_reply_a(iface, to, announce_ttl);
                        service_announce_services(iface, to, announce_ttl);
                } else {

-                       /* First dot separates instance name from the rest */
-                       char *dot = strchr(name, '.');
-                       /* Length of queried instance */
-                       size_t len = dot ? dot - name : 0;
-
-                       /* Make sure it's query for the instance name we use */
-                       if (len && len == strlen(umdns_host_label) &&
-                           !strncmp(name, umdns_host_label, len))
-                               service_reply(iface, to, NULL, dot + 1, announce_ttl);
+                       if (name[0] == '_') {
+                               service_reply(iface, to, NULL, name, announce_ttl);
+                       } else {
+                               /* First dot separates instance name from the rest */
+                               char *dot = strchr(name, '.');
+
+                               if (dot) {
+                                       *dot = '\0';
+                                       service_reply(iface, to, name, dot + 1, announce_ttl);
+                                       *dot = '.';
+                               }
+                       }

                }
                break;
 
                }
                break;