Fix comment typo in cache_gc_timer

[project/mdnsd.git] / dns.c

diff --git a/dns.c b/dns.c
index 89cd4ce5a76fc4ebd736784cf6d6fcbe4180bf0d..7c49236a30cc27d6a99b9d5d7b88ea58fc89fd4f 100644 (file)
--- a/dns.c
+++ b/dns.c
@@ -15,6 +15,7 @@
 #include <sys/stat.h>
 
 #include <fcntl.h>
+#include <ifaddrs.h>
 #include <time.h>
 #include <stdio.h>
 #include <unistd.h>
@@ -67,7 +68,7 @@ dns_type_string(uint16_t type)
 }
 
 void
-dns_send_question(struct interface *iface, const char *question, int type, int unicast)
+dns_send_question(struct interface *iface, const char *question, int type, int multicast)
 {
        static struct dns_header h;
        static struct dns_question q;
@@ -87,7 +88,7 @@ dns_send_question(struct interface *iface, const char *question, int type, int u
        int len;
 
        h.questions = cpu_to_be16(1);
-       q.class = cpu_to_be16(((unicast) ? (CLASS_UNICAST) : (0))  | 1);
+       q.class = cpu_to_be16((multicast ? 0 : CLASS_UNICAST) | 1);
        q.type = cpu_to_be16(type);
 
        len = dn_comp(question, (void *) dns_buffer, sizeof(dns_buffer), NULL, NULL);
@@ -97,8 +98,8 @@ dns_send_question(struct interface *iface, const char *question, int type, int u
        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)
-               perror("failed to send question :");
+       if (interface_send_packet(iface, NULL, iov, ARRAY_SIZE(iov)) < 0)
+               perror("failed to send question");
 }
 
 
@@ -137,7 +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;
@@ -176,8 +177,37 @@ 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)
-               fprintf(stderr, "failed to send question\n");
+       if (interface_send_packet(iface, to, iov, n_iov) < 0)
+               perror("failed to send answer");
+}
+
+void
+dns_reply_a(struct interface *iface, struct sockaddr *to, int ttl)
+{
+       struct ifaddrs *ifap, *ifa;
+       struct sockaddr_in *sa;
+       struct sockaddr_in6 *sa6;
+
+       getifaddrs(&ifap);
+
+       dns_init_answer();
+       for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
+               if (strcmp(ifa->ifa_name, iface->name))
+                       continue;
+               if (ifa->ifa_addr->sa_family == AF_INET) {
+                       sa = (struct sockaddr_in *) ifa->ifa_addr;
+                       dns_add_answer(TYPE_A, (uint8_t *) &sa->sin_addr, 4, ttl);
+               }
+               if (ifa->ifa_addr->sa_family == AF_INET6) {
+                       uint8_t ll_prefix[] = {0xfe, 0x80 };
+                       sa6 = (struct sockaddr_in6 *) ifa->ifa_addr;
+                       if (!memcmp(&sa6->sin6_addr, &ll_prefix, 2))
+                               dns_add_answer(TYPE_AAAA, (uint8_t *) &sa6->sin6_addr, 16, ttl);
+               }
+       }
+       dns_send_answer(iface, to, mdns_hostname_local);
+
+       freeifaddrs(ifap);
 }
 
 static int
@@ -319,24 +349,44 @@ parse_answer(struct interface *iface, uint8_t *buffer, int len, uint8_t **b, int
 }
 
 static void
-parse_question(struct interface *iface, char *name, struct dns_question *q)
+parse_question(struct interface *iface, struct sockaddr *from, char *name, struct dns_question *q)
 {
+       struct sockaddr *to;
        char *host;
 
-       if ((q->class & CLASS_UNICAST) && iface->multicast)
+       /* TODO: Multicast if more than one quarter of TTL has passed */
+       if ((q->class & CLASS_UNICAST) && iface->multicast) {
                iface = iface->peer;
+               to = from;
+       } else {
+               to = NULL;
+       }
 
        DBG(1, "Q -> %s %s\n", dns_type_string(q->type), name);
 
        switch (q->type) {
        case TYPE_ANY:
-               if (!strcmp(name, mdns_hostname_local))
-                       service_reply(iface, NULL, announce_ttl);
+               if (!strcmp(name, mdns_hostname_local)) {
+                       dns_reply_a(iface, to, announce_ttl);
+                       service_reply(iface, to, NULL, announce_ttl);
+               }
                break;
 
        case TYPE_PTR:
-               service_announce_services(iface, name, announce_ttl);
-               service_reply(iface, name, announce_ttl);
+               if (!strcmp(name, sdudp)) {
+                       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(mdns_hostname) &&
+                           !strncmp(name, mdns_hostname, len))
+                               service_reply(iface, to, dot + 1, announce_ttl);
+               }
                break;
 
        case TYPE_AAAA:
@@ -345,7 +395,7 @@ parse_question(struct interface *iface, char *name, struct dns_question *q)
                if (host)
                        *host = '\0';
                if (!strcmp(mdns_hostname, name))
-                       service_reply_a(iface, announce_ttl);
+                       dns_reply_a(iface, to, announce_ttl);
                break;
        };
 }
@@ -364,7 +414,7 @@ dns_handle_packet(struct interface *iface, struct sockaddr *s, uint16_t port, ui
        }
 
        if (h->questions && !iface->multicast && port != 5353)
-               // silently drop unicast questions that dont originate from port 5353  
+               /* silently drop unicast questions that dont originate from port 5353 */
                return;
 
        while (h->questions-- > 0) {
@@ -383,7 +433,7 @@ dns_handle_packet(struct interface *iface, struct sockaddr *s, uint16_t port, ui
                }
 
                if (!(h->flags & FLAG_RESPONSE))
-                       parse_question(iface, name, q);
+                       parse_question(iface, s, name, q);
        }
 
        if (!(h->flags & FLAG_RESPONSE))