source4/dns_server/dns_server.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    DNS server startup
   5
   6    Copyright (C) 2010 Kai Blin  <kai@samba.org>
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "smbd/service_task.h"
  24 #include "smbd/service.h"
  25 #include "smbd/service_stream.h"
  26 #include "smbd/process_model.h"
  27 #include "lib/events/events.h"
  28 #include "lib/socket/socket.h"
  29 #include "lib/tsocket/tsocket.h"
  30 #include "libcli/util/tstream.h"
  31 #include "libcli/util/ntstatus.h"
  32 #include "system/network.h"
  33 #include "lib/stream/packet.h"
  34 #include "lib/socket/netif.h"
  35 #include "dns_server/dns_server.h"
  36 #include "param/param.h"
  37 #include "librpc/ndr/libndr.h"
  38 #include "librpc/gen_ndr/ndr_dns.h"
  39 #include "librpc/gen_ndr/ndr_dnsp.h"
  40 #include <ldb.h>
  41 #include "dsdb/samdb/samdb.h"
  42 #include "dsdb/common/util.h"
  43 #include "auth/session.h"
  44 #include "lib/util/dlinklist.h"
  45 #include "lib/util/tevent_werror.h"
  46
  47 NTSTATUS server_service_dns_init(void);
  48
  49 /* hold information about one dns socket */
  50 struct dns_socket {
  51         struct dns_server *dns;
  52         struct tsocket_address *local_address;
  53 };
  54
  55 struct dns_udp_socket {
  56         struct dns_socket *dns_socket;
  57         struct tdgram_context *dgram;
  58         struct tevent_queue *send_queue;
  59 };
  60
  61 /*
  62   state of an open tcp connection
  63 */
  64 struct dns_tcp_connection {
  65         /* stream connection we belong to */
  66         struct stream_connection *conn;
  67
  68         /* the dns_server the connection belongs to */
  69         struct dns_socket *dns_socket;
  70
  71         struct tstream_context *tstream;
  72
  73         struct tevent_queue *send_queue;
  74 };
  75
  76 static void dns_tcp_terminate_connection(struct dns_tcp_connection *dnsconn, const char *reason)
  77 {
  78         stream_terminate_connection(dnsconn->conn, reason);
  79 }
  80
  81 static void dns_tcp_recv(struct stream_connection *conn, uint16_t flags)
  82 {
  83         struct dns_tcp_connection *dnsconn = talloc_get_type(conn->private_data,
  84                                                              struct dns_tcp_connection);
  85         /* this should never be triggered! */
  86         dns_tcp_terminate_connection(dnsconn, "dns_tcp_recv: called");
  87 }
  88
  89 static void dns_tcp_send(struct stream_connection *conn, uint16_t flags)
  90 {
  91         struct dns_tcp_connection *dnsconn = talloc_get_type(conn->private_data,
  92                                                              struct dns_tcp_connection);
  93         /* this should never be triggered! */
  94         dns_tcp_terminate_connection(dnsconn, "dns_tcp_send: called");
  95 }
  96
  97 struct dns_process_state {
  98         DATA_BLOB *in;
  99         struct dns_name_packet in_packet;
 100         struct dns_request_state state;
 101         uint16_t dns_err;
 102         struct dns_name_packet out_packet;
 103         DATA_BLOB out;
 104 };
 105
 106 static void dns_process_done(struct tevent_req *subreq);
 107
 108 static struct tevent_req *dns_process_send(TALLOC_CTX *mem_ctx,
 109                                            struct tevent_context *ev,
 110                                            struct dns_server *dns,
 111                                            DATA_BLOB *in)
 112 {
 113         struct tevent_req *req, *subreq;
 114         struct dns_process_state *state;
 115         enum ndr_err_code ndr_err;
 116         WERROR ret;
 117
 118         req = tevent_req_create(mem_ctx, &state, struct dns_process_state);
 119         if (req == NULL) {
 120                 return NULL;
 121         }
 122         state->in = in;
 123
 124         if (in->length < 12) {
 125                 tevent_req_werror(req, WERR_INVALID_PARAM);
 126                 return tevent_req_post(req, ev);
 127         }
 128         dump_data(8, in->data, in->length);
 129
 130         ndr_err = ndr_pull_struct_blob(
 131                 in, state, &state->in_packet,
 132                 (ndr_pull_flags_fn_t)ndr_pull_dns_name_packet);
 133
 134         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 135                 state->dns_err = DNS_RCODE_FORMERR;
 136                 tevent_req_done(req);
 137                 return tevent_req_post(req, ev);
 138         }
 139         if (DEBUGLVL(8)) {
 140                 NDR_PRINT_DEBUG(dns_name_packet, &state->in_packet);
 141         }
 142
 143         state->state.flags = state->in_packet.operation;
 144         state->state.flags |= DNS_FLAG_REPLY;
 145
 146         if (lpcfg_dns_recursive_queries(dns->task->lp_ctx)) {
 147                 state->state.flags |= DNS_FLAG_RECURSION_AVAIL;
 148         }
 149
 150         state->out_packet = state->in_packet;
 151
 152         switch (state->in_packet.operation & DNS_OPCODE) {
 153         case DNS_OPCODE_QUERY:
 154                 subreq = dns_server_process_query_send(
 155                         state, ev, dns, &state->state, &state->in_packet);
 156                 if (tevent_req_nomem(subreq, req)) {
 157                         return tevent_req_post(req, ev);
 158                 }
 159                 tevent_req_set_callback(subreq, dns_process_done, req);
 160                 return req;
 161         case DNS_OPCODE_UPDATE:
 162                 ret = dns_server_process_update(
 163                         dns, &state->state, state, &state->in_packet,
 164                         &state->out_packet.answers, &state->out_packet.ancount,
 165                         &state->out_packet.nsrecs,  &state->out_packet.nscount,
 166                         &state->out_packet.additional,
 167                         &state->out_packet.arcount);
 168                 break;
 169         default:
 170                 ret = WERR_DNS_ERROR_RCODE_NOT_IMPLEMENTED;
 171         }
 172         if (!W_ERROR_IS_OK(ret)) {
 173                 state->dns_err = werr_to_dns_err(ret);
 174         }
 175         tevent_req_done(req);
 176         return tevent_req_post(req, ev);
 177 }
 178
 179 static void dns_process_done(struct tevent_req *subreq)
 180 {
 181         struct tevent_req *req = tevent_req_callback_data(
 182                 subreq, struct tevent_req);
 183         struct dns_process_state *state = tevent_req_data(
 184                 req, struct dns_process_state);
 185         WERROR ret;
 186
 187         ret = dns_server_process_query_recv(
 188                 subreq, state,
 189                 &state->out_packet.answers, &state->out_packet.ancount,
 190                 &state->out_packet.nsrecs,  &state->out_packet.nscount,
 191                 &state->out_packet.additional, &state->out_packet.arcount);
 192         TALLOC_FREE(subreq);
 193
 194         if (!W_ERROR_IS_OK(ret)) {
 195                 state->dns_err = werr_to_dns_err(ret);
 196         }
 197         tevent_req_done(req);
 198 }
 199
 200 static WERROR dns_process_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 201                                DATA_BLOB *out)
 202 {
 203         struct dns_process_state *state = tevent_req_data(
 204                 req, struct dns_process_state);
 205         enum ndr_err_code ndr_err;
 206         WERROR ret;
 207
 208         if (tevent_req_is_werror(req, &ret)) {
 209                 return ret;
 210         }
 211         if (state->dns_err != DNS_RCODE_OK) {
 212                 goto drop;
 213         }
 214         state->out_packet.operation |= state->state.flags;
 215
 216         ndr_err = ndr_push_struct_blob(
 217                 out, mem_ctx, &state->out_packet,
 218                 (ndr_push_flags_fn_t)ndr_push_dns_name_packet);
 219         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 220                 DEBUG(1, ("Failed to push packet: %s!\n",
 221                           ndr_errstr(ndr_err)));
 222                 state->dns_err = DNS_RCODE_SERVFAIL;
 223                 goto drop;
 224         }
 225         return WERR_OK;
 226
 227 drop:
 228         *out = data_blob_talloc(mem_ctx, state->in->data, state->in->length);
 229         if (out->data == NULL) {
 230                 return WERR_NOMEM;
 231         }
 232         out->data[2] |= 0x80; /* Toggle DNS_FLAG_REPLY */
 233         out->data[3] |= state->dns_err;
 234         return WERR_OK;
 235 }
 236
 237 struct dns_tcp_call {
 238         struct dns_tcp_connection *dns_conn;
 239         DATA_BLOB in;
 240         DATA_BLOB out;
 241         uint8_t out_hdr[4];
 242         struct iovec out_iov[2];
 243 };
 244
 245 static void dns_tcp_call_process_done(struct tevent_req *subreq);
 246 static void dns_tcp_call_writev_done(struct tevent_req *subreq);
 247
 248 static void dns_tcp_call_loop(struct tevent_req *subreq)
 249 {
 250         struct dns_tcp_connection *dns_conn = tevent_req_callback_data(subreq,
 251                                       struct dns_tcp_connection);
 252         struct dns_server *dns = dns_conn->dns_socket->dns;
 253         struct dns_tcp_call *call;
 254         NTSTATUS status;
 255
 256         call = talloc(dns_conn, struct dns_tcp_call);
 257         if (call == NULL) {
 258                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 259                                 "no memory for dns_tcp_call");
 260                 return;
 261         }
 262         call->dns_conn = dns_conn;
 263
 264         status = tstream_read_pdu_blob_recv(subreq,
 265                                             call,
 266                                             &call->in);
 267         TALLOC_FREE(subreq);
 268         if (!NT_STATUS_IS_OK(status)) {
 269                 const char *reason;
 270
 271                 reason = talloc_asprintf(call, "dns_tcp_call_loop: "
 272                                          "tstream_read_pdu_blob_recv() - %s",
 273                                          nt_errstr(status));
 274                 if (!reason) {
 275                         reason = nt_errstr(status);
 276                 }
 277
 278                 dns_tcp_terminate_connection(dns_conn, reason);
 279                 return;
 280         }
 281
 282         DEBUG(10,("Received DNS TCP packet of length %lu from %s\n",
 283                  (long) call->in.length,
 284                  tsocket_address_string(dns_conn->conn->remote_address, call)));
 285
 286         /* skip length header */
 287         call->in.data += 2;
 288         call->in.length -= 2;
 289
 290         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 291                                   &call->in);
 292         if (subreq == NULL) {
 293                 dns_tcp_terminate_connection(
 294                         dns_conn, "dns_tcp_call_loop: dns_process_send "
 295                         "failed\n");
 296                 return;
 297         }
 298         tevent_req_set_callback(subreq, dns_tcp_call_process_done, call);
 299
 300         /*
 301          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 302          * packet_full_request_u16 provides the pdu length then.
 303          */
 304         subreq = tstream_read_pdu_blob_send(dns_conn,
 305                                             dns_conn->conn->event.ctx,
 306                                             dns_conn->tstream,
 307                                             2, /* initial_read_size */
 308                                             packet_full_request_u16,
 309                                             dns_conn);
 310         if (subreq == NULL) {
 311                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 312                                 "no memory for tstream_read_pdu_blob_send");
 313                 return;
 314         }
 315         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 316 }
 317
 318 static void dns_tcp_call_process_done(struct tevent_req *subreq)
 319 {
 320         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 321                         struct dns_tcp_call);
 322         struct dns_tcp_connection *dns_conn = call->dns_conn;
 323         WERROR err;
 324
 325         err = dns_process_recv(subreq, call, &call->out);
 326         TALLOC_FREE(subreq);
 327         if (!W_ERROR_IS_OK(err)) {
 328                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 329                 dns_tcp_terminate_connection(dns_conn,
 330                                 "dns_tcp_call_loop: process function failed");
 331                 return;
 332         }
 333
 334         /* First add the length of the out buffer */
 335         RSSVAL(call->out_hdr, 0, call->out.length);
 336         call->out_iov[0].iov_base = (char *) call->out_hdr;
 337         call->out_iov[0].iov_len = 2;
 338
 339         call->out_iov[1].iov_base = (char *) call->out.data;
 340         call->out_iov[1].iov_len = call->out.length;
 341
 342         subreq = tstream_writev_queue_send(call,
 343                                            dns_conn->conn->event.ctx,
 344                                            dns_conn->tstream,
 345                                            dns_conn->send_queue,
 346                                            call->out_iov, 2);
 347         if (subreq == NULL) {
 348                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 349                                 "no memory for tstream_writev_queue_send");
 350                 return;
 351         }
 352         tevent_req_set_callback(subreq, dns_tcp_call_writev_done, call);
 353 }
 354
 355 static void dns_tcp_call_writev_done(struct tevent_req *subreq)
 356 {
 357         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 358                         struct dns_tcp_call);
 359         int sys_errno;
 360         int rc;
 361
 362         rc = tstream_writev_queue_recv(subreq, &sys_errno);
 363         TALLOC_FREE(subreq);
 364         if (rc == -1) {
 365                 const char *reason;
 366
 367                 reason = talloc_asprintf(call, "dns_tcp_call_writev_done: "
 368                                          "tstream_writev_queue_recv() - %d:%s",
 369                                          sys_errno, strerror(sys_errno));
 370                 if (!reason) {
 371                         reason = "dns_tcp_call_writev_done: tstream_writev_queue_recv() failed";
 372                 }
 373
 374                 dns_tcp_terminate_connection(call->dns_conn, reason);
 375                 return;
 376         }
 377
 378         /* We don't care about errors */
 379
 380         talloc_free(call);
 381 }
 382
 383 /*
 384   called when we get a new connection
 385 */
 386 static void dns_tcp_accept(struct stream_connection *conn)
 387 {
 388         struct dns_socket *dns_socket;
 389         struct dns_tcp_connection *dns_conn;
 390         struct tevent_req *subreq;
 391         int rc;
 392
 393         dns_conn = talloc_zero(conn, struct dns_tcp_connection);
 394         if (dns_conn == NULL) {
 395                 stream_terminate_connection(conn,
 396                                 "dns_tcp_accept: out of memory");
 397                 return;
 398         }
 399
 400         dns_conn->send_queue = tevent_queue_create(conn, "dns_tcp_accept");
 401         if (dns_conn->send_queue == NULL) {
 402                 stream_terminate_connection(conn,
 403                                 "dns_tcp_accept: out of memory");
 404                 return;
 405         }
 406
 407         dns_socket = talloc_get_type(conn->private_data, struct dns_socket);
 408
 409         TALLOC_FREE(conn->event.fde);
 410
 411         rc = tstream_bsd_existing_socket(dns_conn,
 412                         socket_get_fd(conn->socket),
 413                         &dns_conn->tstream);
 414         if (rc < 0) {
 415                 stream_terminate_connection(conn,
 416                                 "dns_tcp_accept: out of memory");
 417                 return;
 418         }
 419
 420         dns_conn->conn = conn;
 421         dns_conn->dns_socket = dns_socket;
 422         conn->private_data = dns_conn;
 423
 424         /*
 425          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 426          * packet_full_request_u16 provides the pdu length then.
 427          */
 428         subreq = tstream_read_pdu_blob_send(dns_conn,
 429                                             dns_conn->conn->event.ctx,
 430                                             dns_conn->tstream,
 431                                             2, /* initial_read_size */
 432                                             packet_full_request_u16,
 433                                             dns_conn);
 434         if (subreq == NULL) {
 435                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_accept: "
 436                                 "no memory for tstream_read_pdu_blob_send");
 437                 return;
 438         }
 439         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 440 }
 441
 442 static const struct stream_server_ops dns_tcp_stream_ops = {
 443         .name                   = "dns_tcp",
 444         .accept_connection      = dns_tcp_accept,
 445         .recv_handler           = dns_tcp_recv,
 446         .send_handler           = dns_tcp_send
 447 };
 448
 449 struct dns_udp_call {
 450         struct dns_udp_socket *sock;
 451         struct tsocket_address *src;
 452         DATA_BLOB in;
 453         DATA_BLOB out;
 454 };
 455
 456 static void dns_udp_call_process_done(struct tevent_req *subreq);
 457 static void dns_udp_call_sendto_done(struct tevent_req *subreq);
 458
 459 static void dns_udp_call_loop(struct tevent_req *subreq)
 460 {
 461         struct dns_udp_socket *sock = tevent_req_callback_data(subreq,
 462                                       struct dns_udp_socket);
 463         struct dns_server *dns = sock->dns_socket->dns;
 464         struct dns_udp_call *call;
 465         uint8_t *buf;
 466         ssize_t len;
 467         int sys_errno;
 468
 469         call = talloc(sock, struct dns_udp_call);
 470         if (call == NULL) {
 471                 talloc_free(call);
 472                 goto done;
 473         }
 474         call->sock = sock;
 475
 476         len = tdgram_recvfrom_recv(subreq, &sys_errno,
 477                                    call, &buf, &call->src);
 478         TALLOC_FREE(subreq);
 479         if (len == -1) {
 480                 talloc_free(call);
 481                 goto done;
 482         }
 483
 484         call->in.data = buf;
 485         call->in.length = len;
 486
 487         DEBUG(10,("Received DNS UDP packet of length %lu from %s\n",
 488                  (long)call->in.length,
 489                  tsocket_address_string(call->src, call)));
 490
 491         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 492                                   &call->in);
 493         if (subreq == NULL) {
 494                 TALLOC_FREE(call);
 495                 goto done;
 496         }
 497         tevent_req_set_callback(subreq, dns_udp_call_process_done, call);
 498
 499 done:
 500         subreq = tdgram_recvfrom_send(sock,
 501                                       sock->dns_socket->dns->task->event_ctx,
 502                                       sock->dgram);
 503         if (subreq == NULL) {
 504                 task_server_terminate(sock->dns_socket->dns->task,
 505                                       "no memory for tdgram_recvfrom_send",
 506                                       true);
 507                 return;
 508         }
 509         tevent_req_set_callback(subreq, dns_udp_call_loop, sock);
 510 }
 511
 512 static void dns_udp_call_process_done(struct tevent_req *subreq)
 513 {
 514         struct dns_udp_call *call = tevent_req_callback_data(
 515                 subreq, struct dns_udp_call);
 516         struct dns_udp_socket *sock = call->sock;
 517         struct dns_server *dns = sock->dns_socket->dns;
 518         WERROR err;
 519
 520         err = dns_process_recv(subreq, call, &call->out);
 521         TALLOC_FREE(subreq);
 522         if (!W_ERROR_IS_OK(err)) {
 523                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 524                 TALLOC_FREE(call);
 525                 return;
 526         }
 527
 528         subreq = tdgram_sendto_queue_send(call,
 529                                           dns->task->event_ctx,
 530                                           sock->dgram,
 531                                           sock->send_queue,
 532                                           call->out.data,
 533                                           call->out.length,
 534                                           call->src);
 535         if (subreq == NULL) {
 536                 talloc_free(call);
 537                 return;
 538         }
 539         tevent_req_set_callback(subreq, dns_udp_call_sendto_done, call);
 540
 541 }
 542 static void dns_udp_call_sendto_done(struct tevent_req *subreq)
 543 {
 544         struct dns_udp_call *call = tevent_req_callback_data(subreq,
 545                                        struct dns_udp_call);
 546         ssize_t ret;
 547         int sys_errno;
 548
 549         ret = tdgram_sendto_queue_recv(subreq, &sys_errno);
 550
 551         /* We don't care about errors */
 552
 553         talloc_free(call);
 554 }
 555
 556 /*
 557   start listening on the given address
 558 */
 559 static NTSTATUS dns_add_socket(struct dns_server *dns,
 560                                const struct model_ops *model_ops,
 561                                const char *name,
 562                                const char *address,
 563                                uint16_t port)
 564 {
 565         struct dns_socket *dns_socket;
 566         struct dns_udp_socket *dns_udp_socket;
 567         struct tevent_req *udpsubreq;
 568         NTSTATUS status;
 569         int ret;
 570
 571         dns_socket = talloc(dns, struct dns_socket);
 572         NT_STATUS_HAVE_NO_MEMORY(dns_socket);
 573
 574         dns_socket->dns = dns;
 575
 576         ret = tsocket_address_inet_from_strings(dns_socket, "ip",
 577                                                 address, port,
 578                                                 &dns_socket->local_address);
 579         if (ret != 0) {
 580                 status = map_nt_error_from_unix_common(errno);
 581                 return status;
 582         }
 583
 584         status = stream_setup_socket(dns->task,
 585                                      dns->task->event_ctx,
 586                                      dns->task->lp_ctx,
 587                                      model_ops,
 588                                      &dns_tcp_stream_ops,
 589                                      "ip", address, &port,
 590                                      lpcfg_socket_options(dns->task->lp_ctx),
 591                                      dns_socket);
 592         if (!NT_STATUS_IS_OK(status)) {
 593                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 594                          address, port, nt_errstr(status)));
 595                 talloc_free(dns_socket);
 596                 return status;
 597         }
 598
 599         dns_udp_socket = talloc(dns_socket, struct dns_udp_socket);
 600         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket);
 601
 602         dns_udp_socket->dns_socket = dns_socket;
 603
 604         ret = tdgram_inet_udp_socket(dns_socket->local_address,
 605                                      NULL,
 606                                      dns_udp_socket,
 607                                      &dns_udp_socket->dgram);
 608         if (ret != 0) {
 609                 status = map_nt_error_from_unix_common(errno);
 610                 DEBUG(0,("Failed to bind to %s:%u UDP - %s\n",
 611                          address, port, nt_errstr(status)));
 612                 return status;
 613         }
 614
 615         dns_udp_socket->send_queue = tevent_queue_create(dns_udp_socket,
 616                                                          "dns_udp_send_queue");
 617         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket->send_queue);
 618
 619         udpsubreq = tdgram_recvfrom_send(dns_udp_socket,
 620                                          dns->task->event_ctx,
 621                                          dns_udp_socket->dgram);
 622         NT_STATUS_HAVE_NO_MEMORY(udpsubreq);
 623         tevent_req_set_callback(udpsubreq, dns_udp_call_loop, dns_udp_socket);
 624
 625         return NT_STATUS_OK;
 626 }
 627
 628 /*
 629   setup our listening sockets on the configured network interfaces
 630 */
 631 static NTSTATUS dns_startup_interfaces(struct dns_server *dns, struct loadparm_context *lp_ctx,
 632                                        struct interface *ifaces)
 633 {
 634         const struct model_ops *model_ops;
 635         int num_interfaces;
 636         TALLOC_CTX *tmp_ctx = talloc_new(dns);
 637         NTSTATUS status;
 638         int i;
 639
 640         /* within the dns task we want to be a single process, so
 641            ask for the single process model ops and pass these to the
 642            stream_setup_socket() call. */
 643         model_ops = process_model_startup("single");
 644         if (!model_ops) {
 645                 DEBUG(0,("Can't find 'single' process model_ops\n"));
 646                 return NT_STATUS_INTERNAL_ERROR;
 647         }
 648
 649         num_interfaces = iface_list_count(ifaces);
 650
 651         for (i=0; i<num_interfaces; i++) {
 652                 const char *address = talloc_strdup(tmp_ctx, iface_list_n_ip(ifaces, i));
 653
 654                 status = dns_add_socket(dns, model_ops, "dns", address, DNS_SERVICE_PORT);
 655                 NT_STATUS_NOT_OK_RETURN(status);
 656         }
 657
 658         talloc_free(tmp_ctx);
 659
 660         return NT_STATUS_OK;
 661 }
 662
 663 static int dns_server_sort_zones(struct ldb_message **m1, struct ldb_message **m2)
 664 {
 665         const char *n1, *n2;
 666         size_t l1, l2;
 667
 668         n1 = ldb_msg_find_attr_as_string(*m1, "name", NULL);
 669         n2 = ldb_msg_find_attr_as_string(*m2, "name", NULL);
 670
 671         l1 = strlen(n1);
 672         l2 = strlen(n2);
 673
 674         /* If the string lengths are not equal just sort by length */
 675         if (l1 != l2) {
 676                 /* If m1 is the larger zone name, return it first */
 677                 return l2 - l1;
 678         }
 679
 680         /*TODO: We need to compare DNs here, we want the DomainDNSZones first */
 681         return 0;
 682 }
 683
 684 static void dns_task_init(struct task_server *task)
 685 {
 686         struct dns_server *dns;
 687         NTSTATUS status;
 688         struct interface *ifaces;
 689         int ret;
 690         struct ldb_result *res;
 691         static const char * const attrs[] = { "name", NULL};
 692         unsigned int i;
 693
 694         switch (lpcfg_server_role(task->lp_ctx)) {
 695         case ROLE_STANDALONE:
 696                 task_server_terminate(task, "dns: no DNS required in standalone configuration", false);
 697                 return;
 698         case ROLE_DOMAIN_MEMBER:
 699                 task_server_terminate(task, "dns: no DNS required in member server configuration", false);
 700                 return;
 701         case ROLE_ACTIVE_DIRECTORY_DC:
 702                 /* Yes, we want a DNS */
 703                 break;
 704         }
 705
 706         load_interface_list(task, task->lp_ctx, &ifaces);
 707
 708         if (iface_list_count(ifaces) == 0) {
 709                 task_server_terminate(task, "dns: no network interfaces configured", false);
 710                 return;
 711         }
 712
 713         task_server_set_title(task, "task[dns]");
 714
 715         dns = talloc_zero(task, struct dns_server);
 716         if (dns == NULL) {
 717                 task_server_terminate(task, "dns: out of memory", true);
 718                 return;
 719         }
 720
 721         dns->task = task;
 722
 723         dns->samdb = samdb_connect(dns, dns->task->event_ctx, dns->task->lp_ctx,
 724                               system_session(dns->task->lp_ctx), 0);
 725         if (!dns->samdb) {
 726                 task_server_terminate(task, "dns: samdb_connect failed", true);
 727                 return;
 728         }
 729
 730         // TODO: this search does not work against windows
 731         ret = dsdb_search(dns->samdb, dns, &res, NULL, LDB_SCOPE_SUBTREE,
 732                           attrs, DSDB_SEARCH_SEARCH_ALL_PARTITIONS, "(objectClass=dnsZone)");
 733         if (ret != LDB_SUCCESS) {
 734                 task_server_terminate(task,
 735                                       "dns: failed to look up root DNS zones",
 736                                       true);
 737                 return;
 738         }
 739
 740         TYPESAFE_QSORT(res->msgs, res->count, dns_server_sort_zones);
 741
 742         for (i=0; i < res->count; i++) {
 743                 struct dns_server_zone *z;
 744
 745                 z = talloc_zero(dns, struct dns_server_zone);
 746                 if (z == NULL) {
 747                 }
 748
 749                 z->name = ldb_msg_find_attr_as_string(res->msgs[i], "name", NULL);
 750                 z->dn = talloc_move(z, &res->msgs[i]->dn);
 751
 752                 DLIST_ADD_END(dns->zones, z, NULL);
 753         }
 754
 755         status = dns_startup_interfaces(dns, task->lp_ctx, ifaces);
 756         if (!NT_STATUS_IS_OK(status)) {
 757                 task_server_terminate(task, "dns failed to setup interfaces", true);
 758                 return;
 759         }
 760 }
 761
 762 NTSTATUS server_service_dns_init(void)
 763 {
 764         return register_server_service("dns", dns_task_init);
 765 }