Fix critical bug in DNS resolver.

diff --git a/src/dns.c b/src/dns.c
index 77063d9c1c06795f50af731da0abbf5531e173c0..f387c0c4835ab98d03e384a6a45c99c9ab04b65b 100644 (file)
--- a/src/dns.c
+++ b/src/dns.c
@@ -787,6 +787,7 @@ send_dns_request (struct rspamd_dns_request *req)
                }
        }
        else if (r < req->pos) {
+               msg_err ("incomplete send over UDP socket, seems to be internal bug");
                event_set (&req->io_event, req->sock, EV_WRITE, dns_retransmit_handler, req);
                event_base_set (req->resolver->ev_base, &req->io_event);
                event_add (&req->io_event, &req->tv);
@@ -1219,6 +1220,7 @@ dns_parse_reply (gint sock, guint8 *in, gint r, struct rspamd_dns_resolver *reso
        id = header->qid;
        if ((req = g_hash_table_lookup (ioc->requests, &id)) == NULL) {
                /* No such requests found */
+               msg_debug ("DNS request with id %d has not been found for IO channel", (gint)id);
                return FALSE;
        }
        *req_out = req;
@@ -1228,6 +1230,7 @@ dns_parse_reply (gint sock, guint8 *in, gint r, struct rspamd_dns_resolver *reso
         */
        if ((pos = dns_request_reply_cmp (req, in + sizeof (struct dns_header),
                        r - sizeof (struct dns_header))) == NULL) {
+               msg_debug ("DNS request with id %d is for different query, ignoring", (gint)id);
                return FALSE;
        }
        /*
@@ -1324,37 +1327,12 @@ dns_timer_cb (gint fd, short what, void *arg)
        req->retransmits ++;
        serv = req->io->srv;
        if (req->retransmits >= req->resolver->max_retransmits) {
-               msg_err ("maximum number of retransmits expired for resolving %s of type %s", req->requested_name, dns_strtype (req->type));
+               msg_err ("maximum number of retransmits expired for resolving %s of type %s",
+                               req->requested_name, dns_strtype (req->type));
                dns_check_throttling (req->resolver);
                req->resolver->errors ++;
                goto err;
        }
-       /* Select other server */
-       if (req->resolver->is_master_slave) {
-               serv = (struct rspamd_dns_server *)get_upstream_master_slave (req->resolver->servers,
-                                       req->resolver->servers_num, sizeof (struct rspamd_dns_server),
-                                       req->time, DEFAULT_UPSTREAM_ERROR_TIME, DEFAULT_UPSTREAM_DEAD_TIME, DEFAULT_UPSTREAM_MAXERRORS);
-       }
-       else {
-               serv = (struct rspamd_dns_server *)get_upstream_round_robin (req->resolver->servers,
-                       req->resolver->servers_num, sizeof (struct rspamd_dns_server),
-                       req->time, DEFAULT_UPSTREAM_ERROR_TIME, DEFAULT_UPSTREAM_DEAD_TIME, DEFAULT_UPSTREAM_MAXERRORS);
-       }
-       if (serv == NULL) {
-               goto err;
-       }
-
-       req->io = serv->cur_io_channel;
-       if (req->io == NULL) {
-               msg_err ("cannot find suitable io channel for the server %s", serv->name);
-               goto err;
-       }
-       serv->cur_io_channel = serv->cur_io_channel->next;
-       
-       if (req->io->sock == -1) {
-               req->io->sock =  make_universal_socket (serv->name, dns_port, SOCK_DGRAM, TRUE, FALSE, FALSE);
-       }
-       req->sock = req->io->sock;
 
        if (req->sock == -1) {
                goto err;
@@ -1364,10 +1342,13 @@ dns_timer_cb (gint fd, short what, void *arg)
        if (r == -1) {
                goto err;
        }
+
+       msg_debug ("retransmit DNS request with ID %d", (int)req->id);
        evtimer_add (&req->timer_event, &req->tv);
 
        return;
 err:
+       msg_debug ("error on retransmitting DNS request with ID %d", (int)req->id);
        rep = memory_pool_alloc0 (req->pool, sizeof (struct rspamd_dns_reply));
        rep->request = req;
        rep->code = DNS_RC_SERVFAIL;
@@ -1542,9 +1523,6 @@ make_dns_request (struct rspamd_dns_resolver *resolver,
        r = send_dns_request (req);
 
        if (r == 1) {
-               /* Add timer event */
-               evtimer_add (&req->timer_event, &req->tv);
-
                /* Add request to hash table */
                r = 0;
                while (g_hash_table_lookup (req->io->requests, &req->id)) {
@@ -1557,6 +1535,8 @@ make_dns_request (struct rspamd_dns_resolver *resolver,
                                return FALSE;
                        }
                }
+               /* Add timer event */
+               evtimer_add (&req->timer_event, &req->tv);
                g_hash_table_insert (req->io->requests, &req->id, req);
                register_async_event (session, (event_finalizer_t)dns_fin_cb, req,
                                g_quark_from_static_string ("dns resolver"));