Send an error response when the DNS request times out

diff --git a/plugins/dnsproxy.c b/plugins/dnsproxy.c
index 6cd2e90..d383db1 100644 (file)
--- a/plugins/dnsproxy.c
+++ b/plugins/dnsproxy.c
@@ -161,13 +161,57 @@ static struct server_data *find_server(const char *interface,
        return NULL;
 }
 
+
+static void send_response(int sk, unsigned char *buf, int len,
+                               const struct sockaddr *to, socklen_t tolen,
+                               int protocol)
+{
+       struct domain_hdr *hdr;
+       int err, offset;
+
+       DBG("");
+
+       switch (protocol) {
+       case IPPROTO_UDP:
+               offset = 0;
+               break;
+
+       case IPPROTO_TCP:
+               offset = 2;
+               break;
+
+       default:
+               return;
+       }
+
+       if (len < 12)
+               return;
+
+       hdr = (void*) (buf + offset);
+
+       DBG("id 0x%04x qr %d opcode %d", hdr->id, hdr->qr, hdr->opcode);
+
+       hdr->qr = 1;
+       hdr->rcode = 2;
+
+       hdr->ancount = 0;
+       hdr->nscount = 0;
+       hdr->arcount = 0;
+
+       err = sendto(sk, buf, len, 0, to, tolen);
+}
+
 static gboolean request_timeout(gpointer user_data)
 {
        struct request_data *req = user_data;
 
        DBG("id 0x%04x", req->srcid);
 
+       if (req == NULL)
+               return FALSE;
+
        request_list = g_slist_remove(request_list, req);
+       req->numserv--;
 
        if (req->resplen > 0 && req->resp != NULL) {
                int sk, err;
@@ -176,6 +220,25 @@ static gboolean request_timeout(gpointer user_data)
 
                err = sendto(sk, req->resp, req->resplen, 0,
                                (struct sockaddr *) &req->sin, req->len);
+       } else if (req->request && req->numserv == 0) {
+               struct domain_hdr *hdr;
+
+               if (req->protocol == IPPROTO_TCP) {
+                       hdr = (void *) (req->request + 2);
+                       hdr->id = req->srcid;
+                       send_response(req->client_sk, req->request,
+                                       req->request_len, NULL, 0, IPPROTO_TCP);
+
+               } else if (req->protocol == IPPROTO_UDP) {
+                       int sk;
+
+                       hdr = (void *) (req->request);
+                       hdr->id = req->srcid;
+                       sk = g_io_channel_unix_get_fd(udp_listener_channel);
+                       send_response(sk, req->request, req->request_len,
+                                       (struct sockaddr *)&req->sin,
+                                               sizeof(req->sin), IPPROTO_UDP);
+               }
        }
 
        g_free(req->resp);
@@ -355,43 +418,6 @@ static int forward_dns_reply(unsigned char *reply, int reply_len, int protocol)
        return err;
 }
 
-static void send_response(int sk, unsigned char *buf, int len,
-                               const struct sockaddr *to, socklen_t tolen,
-                               int protocol)
-{
-       struct domain_hdr *hdr;
-       int err, offset;
-
-       switch (protocol) {
-       case IPPROTO_UDP:
-               offset = 0;
-               break;
-
-       case IPPROTO_TCP:
-               offset = 2;
-               break;
-
-       default:
-               return;
-       }
-
-       if (len < 12)
-               return;
-
-       hdr = (void*) (buf + offset);
-
-       DBG("id 0x%04x qr %d opcode %d", hdr->id, hdr->qr, hdr->opcode);
-
-       hdr->qr = 1;
-       hdr->rcode = 2;
-
-       hdr->ancount = 0;
-       hdr->nscount = 0;
-       hdr->arcount = 0;
-
-       err = sendto(sk, buf, len, 0, to, tolen);
-}
-
 static void destroy_server(struct server_data *server)
 {
        DBG("interface %s server %s", server->interface, server->server);