Prepare support for sending unicast DNS answers

[project/mdnsd.git] / dns.c

diff --git a/dns.c b/dns.c
index 91434f20b184d2696129ecb2a3038483a9ee204e..a09b0ec74d8f230b66b709fd0e9ba40c2a1bcc47 100644 (file)
--- a/dns.c
+++ b/dns.c
@@ -98,7 +98,7 @@ dns_send_question(struct interface *iface, const char *question, int type, int m
        iov[1].iov_len = len;
 
        DBG(1, "Q <- %s %s\n", dns_type_string(type), question);
-       if (interface_send_packet(iface, iov, ARRAY_SIZE(iov)) < 0)
+       if (interface_send_packet(iface, NULL, iov, ARRAY_SIZE(iov)) < 0)
                perror("failed to send question :");
 }
 
@@ -138,7 +138,7 @@ dns_add_answer(int type, const uint8_t *rdata, uint16_t rdlength, int ttl)
 }
 
 void
-dns_send_answer(struct interface *iface, const char *answer)
+dns_send_answer(struct interface *iface, struct sockaddr *to, const char *answer)
 {
        uint8_t buffer[256];
        struct blob_attr *attr;
@@ -177,12 +177,12 @@ dns_send_answer(struct interface *iface, const char *answer)
                DBG(1, "A <- %s %s\n", dns_type_string(be16_to_cpu(a->type)), answer);
        }
 
-       if (interface_send_packet(iface, iov, n_iov) < 0)
+       if (interface_send_packet(iface, to, iov, n_iov) < 0)
                fprintf(stderr, "failed to send question\n");
 }
 
 void
-dns_reply_a(struct interface *iface, int ttl)
+dns_reply_a(struct interface *iface, struct sockaddr *to, int ttl)
 {
        struct ifaddrs *ifap, *ifa;
        struct sockaddr_in *sa;
@@ -205,7 +205,7 @@ dns_reply_a(struct interface *iface, int ttl)
                                dns_add_answer(TYPE_AAAA, (uint8_t *) &sa6->sin6_addr, 16, ttl);
                }
        }
-       dns_send_answer(iface, mdns_hostname_local);
+       dns_send_answer(iface, to, mdns_hostname_local);
 
        freeifaddrs(ifap);
 }
@@ -362,14 +362,24 @@ parse_question(struct interface *iface, char *name, struct dns_question *q)
        case TYPE_ANY:
                if (!strcmp(name, mdns_hostname_local)) {
                        service_reply(iface, NULL, announce_ttl);
-                       dns_reply_a(iface, announce_ttl);
+                       dns_reply_a(iface, NULL, announce_ttl);
                }
                break;
 
        case TYPE_PTR:
-               if (!strcmp(name, sdudp))
+               if (!strcmp(name, sdudp)) {
                        service_announce_services(iface, announce_ttl);
-               service_reply(iface, name, 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(mdns_hostname) &&
+                           !strncmp(name, mdns_hostname, len))
+                               service_reply(iface, dot + 1, announce_ttl);
+               }
                break;
 
        case TYPE_AAAA:
@@ -378,7 +388,7 @@ parse_question(struct interface *iface, char *name, struct dns_question *q)
                if (host)
                        *host = '\0';
                if (!strcmp(mdns_hostname, name))
-                       dns_reply_a(iface, announce_ttl);
+                       dns_reply_a(iface, NULL, announce_ttl);
                break;
        };
 }