Fix IPv6 read

[project/mdnsd.git] / dns.c

diff --git a/dns.c b/dns.c
index 585b40f..89cd4ce 100644 (file)
--- a/dns.c
+++ b/dns.c
@@ -39,6 +39,7 @@
 #include "interface.h"
 
 static char name_buffer[MAX_NAME_LEN + 1];
+static char dns_buffer[MAX_NAME_LEN];
 static struct blob_buf ans_buf;
 
 const char*
@@ -66,7 +67,7 @@ dns_type_string(uint16_t type)
 }
 
 void
-dns_send_question(struct interface *iface, const char *question, int type)
+dns_send_question(struct interface *iface, const char *question, int type, int unicast)
 {
        static struct dns_header h;
        static struct dns_question q;
@@ -76,7 +77,7 @@ dns_send_question(struct interface *iface, const char *question, int type)
                        .iov_len = sizeof(h),
                },
                {
-                       .iov_base = name_buffer,
+                       .iov_base = dns_buffer,
                },
                {
                        .iov_base = &q,
@@ -86,19 +87,18 @@ dns_send_question(struct interface *iface, const char *question, int type)
        int len;
 
        h.questions = cpu_to_be16(1);
-       q.class = cpu_to_be16(1);
+       q.class = cpu_to_be16(((unicast) ? (CLASS_UNICAST) : (0))  | 1);
        q.type = cpu_to_be16(type);
 
-       len = dn_comp(question, (void *) name_buffer, sizeof(name_buffer), NULL, NULL);
+       len = dn_comp(question, (void *) dns_buffer, sizeof(dns_buffer), NULL, NULL);
        if (len < 1)
                return;
 
        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)
-               fprintf(stderr, "failed to send question\n");
-       else
-               DBG(1, "Q <- %s %s\n", dns_type_string(type), question);
+               perror("failed to send question :");
 }
 
 
@@ -120,7 +120,7 @@ dns_init_answer(void)
 }
 
 void
-dns_add_answer(int type, const uint8_t *rdata, uint16_t rdlength)
+dns_add_answer(int type, const uint8_t *rdata, uint16_t rdlength, int ttl)
 {
        struct blob_attr *attr;
        struct dns_answer *a;
@@ -129,7 +129,7 @@ dns_add_answer(int type, const uint8_t *rdata, uint16_t rdlength)
        a = blob_data(attr);
        a->type = cpu_to_be16(type);
        a->class = cpu_to_be16(1);
-       a->ttl = cpu_to_be32(announce_ttl);
+       a->ttl = cpu_to_be32(ttl);
        a->rdlength = cpu_to_be16(rdlength);
        memcpy(a + 1, rdata, rdlength);
 
@@ -300,6 +300,9 @@ parse_answer(struct interface *iface, uint8_t *buffer, int len, uint8_t **b, int
                return -1;
        }
 
+       if ((a->class & ~CLASS_FLUSH) != CLASS_IN)
+               return -1;
+
        rdata = *b;
        if (a->rdlength > *rlen) {
                fprintf(stderr, "dropping: bad question\n");
@@ -310,7 +313,7 @@ parse_answer(struct interface *iface, uint8_t *buffer, int len, uint8_t **b, int
        *b += a->rdlength;
 
        if (cache)
-               cache_answer(iface, buffer, len, name, a, rdata);
+               cache_answer(iface, buffer, len, name, a, rdata, a->class & CLASS_FLUSH);
 
        return 0;
 }
@@ -320,17 +323,20 @@ parse_question(struct interface *iface, char *name, struct dns_question *q)
 {
        char *host;
 
+       if ((q->class & CLASS_UNICAST) && iface->multicast)
+               iface = iface->peer;
+
        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);
+                       service_reply(iface, NULL, announce_ttl);
                break;
 
        case TYPE_PTR:
-               service_announce_services(iface, name);
-               service_reply(iface, name);
+               service_announce_services(iface, name, announce_ttl);
+               service_reply(iface, name, announce_ttl);
                break;
 
        case TYPE_AAAA:
@@ -339,13 +345,13 @@ parse_question(struct interface *iface, char *name, struct dns_question *q)
                if (host)
                        *host = '\0';
                if (!strcmp(mdns_hostname, name))
-                       service_reply_a(iface, q->type);
+                       service_reply_a(iface, announce_ttl);
                break;
        };
 }
 
 void
-dns_handle_packet(struct interface *iface, uint8_t *buffer, int len)
+dns_handle_packet(struct interface *iface, struct sockaddr *s, uint16_t port, uint8_t *buffer, int len)
 {
        struct dns_header *h;
        uint8_t *b = buffer;
@@ -357,6 +363,10 @@ dns_handle_packet(struct interface *iface, uint8_t *buffer, int len)
                return;
        }
 
+       if (h->questions && !iface->multicast && port != 5353)
+               // silently drop unicast questions that dont originate from port 5353  
+               return;
+
        while (h->questions-- > 0) {
                char *name = dns_consume_name(buffer, len, &b, &rlen);
                struct dns_question *q;