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 static WERROR dns_process(struct dns_server *dns, TALLOC_CTX *mem_ctx,
 238                           DATA_BLOB *in, DATA_BLOB *out)
 239 {
 240         struct tevent_context *ev;
 241         struct tevent_req *req;
 242         WERROR err = WERR_NOMEM;
 243
 244         ev = tevent_context_init(talloc_tos());
 245         if (ev == NULL) {
 246                 goto fail;
 247         }
 248         req = dns_process_send(ev, ev, dns, in);
 249         if (req == NULL) {
 250                 goto fail;
 251         }
 252         if (!tevent_req_poll_werror(req, ev, &err)) {
 253                 goto fail;
 254         }
 255         err = dns_process_recv(req, mem_ctx, out);
 256 fail:
 257         TALLOC_FREE(ev);
 258         return err;
 259 }
 260
 261 struct dns_tcp_call {
 262         struct dns_tcp_connection *dns_conn;
 263         DATA_BLOB in;
 264         DATA_BLOB out;
 265         uint8_t out_hdr[4];
 266         struct iovec out_iov[2];
 267 };
 268
 269 static void dns_tcp_call_process_done(struct tevent_req *subreq);
 270 static void dns_tcp_call_writev_done(struct tevent_req *subreq);
 271
 272 static void dns_tcp_call_loop(struct tevent_req *subreq)
 273 {
 274         struct dns_tcp_connection *dns_conn = tevent_req_callback_data(subreq,
 275                                       struct dns_tcp_connection);
 276         struct dns_server *dns = dns_conn->dns_socket->dns;
 277         struct dns_tcp_call *call;
 278         NTSTATUS status;
 279
 280         call = talloc(dns_conn, struct dns_tcp_call);
 281         if (call == NULL) {
 282                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 283                                 "no memory for dns_tcp_call");
 284                 return;
 285         }
 286         call->dns_conn = dns_conn;
 287
 288         status = tstream_read_pdu_blob_recv(subreq,
 289                                             call,
 290                                             &call->in);
 291         TALLOC_FREE(subreq);
 292         if (!NT_STATUS_IS_OK(status)) {
 293                 const char *reason;
 294
 295                 reason = talloc_asprintf(call, "dns_tcp_call_loop: "
 296                                          "tstream_read_pdu_blob_recv() - %s",
 297                                          nt_errstr(status));
 298                 if (!reason) {
 299                         reason = nt_errstr(status);
 300                 }
 301
 302                 dns_tcp_terminate_connection(dns_conn, reason);
 303                 return;
 304         }
 305
 306         DEBUG(10,("Received DNS TCP packet of length %lu from %s\n",
 307                  (long) call->in.length,
 308                  tsocket_address_string(dns_conn->conn->remote_address, call)));
 309
 310         /* skip length header */
 311         call->in.data += 2;
 312         call->in.length -= 2;
 313
 314         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 315                                   &call->in);
 316         if (subreq == NULL) {
 317                 dns_tcp_terminate_connection(
 318                         dns_conn, "dns_tcp_call_loop: dns_process_send "
 319                         "failed\n");
 320                 return;
 321         }
 322         tevent_req_set_callback(subreq, dns_tcp_call_process_done, call);
 323
 324         /*
 325          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 326          * packet_full_request_u16 provides the pdu length then.
 327          */
 328         subreq = tstream_read_pdu_blob_send(dns_conn,
 329                                             dns_conn->conn->event.ctx,
 330                                             dns_conn->tstream,
 331                                             2, /* initial_read_size */
 332                                             packet_full_request_u16,
 333                                             dns_conn);
 334         if (subreq == NULL) {
 335                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 336                                 "no memory for tstream_read_pdu_blob_send");
 337                 return;
 338         }
 339         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 340 }
 341
 342 static void dns_tcp_call_process_done(struct tevent_req *subreq)
 343 {
 344         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 345                         struct dns_tcp_call);
 346         struct dns_tcp_connection *dns_conn = call->dns_conn;
 347         WERROR err;
 348
 349         err = dns_process_recv(subreq, call, &call->out);
 350         TALLOC_FREE(subreq);
 351         if (!W_ERROR_IS_OK(err)) {
 352                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 353                 dns_tcp_terminate_connection(dns_conn,
 354                                 "dns_tcp_call_loop: process function failed");
 355                 return;
 356         }
 357
 358         /* First add the length of the out buffer */
 359         RSSVAL(call->out_hdr, 0, call->out.length);
 360         call->out_iov[0].iov_base = (char *) call->out_hdr;
 361         call->out_iov[0].iov_len = 2;
 362
 363         call->out_iov[1].iov_base = (char *) call->out.data;
 364         call->out_iov[1].iov_len = call->out.length;
 365
 366         subreq = tstream_writev_queue_send(call,
 367                                            dns_conn->conn->event.ctx,
 368                                            dns_conn->tstream,
 369                                            dns_conn->send_queue,
 370                                            call->out_iov, 2);
 371         if (subreq == NULL) {
 372                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 373                                 "no memory for tstream_writev_queue_send");
 374                 return;
 375         }
 376         tevent_req_set_callback(subreq, dns_tcp_call_writev_done, call);
 377 }
 378
 379 static void dns_tcp_call_writev_done(struct tevent_req *subreq)
 380 {
 381         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 382                         struct dns_tcp_call);
 383         int sys_errno;
 384         int rc;
 385
 386         rc = tstream_writev_queue_recv(subreq, &sys_errno);
 387         TALLOC_FREE(subreq);
 388         if (rc == -1) {
 389                 const char *reason;
 390
 391                 reason = talloc_asprintf(call, "dns_tcp_call_writev_done: "
 392                                          "tstream_writev_queue_recv() - %d:%s",
 393                                          sys_errno, strerror(sys_errno));
 394                 if (!reason) {
 395                         reason = "dns_tcp_call_writev_done: tstream_writev_queue_recv() failed";
 396                 }
 397
 398                 dns_tcp_terminate_connection(call->dns_conn, reason);
 399                 return;
 400         }
 401
 402         /* We don't care about errors */
 403
 404         talloc_free(call);
 405 }
 406
 407 /*
 408   called when we get a new connection
 409 */
 410 static void dns_tcp_accept(struct stream_connection *conn)
 411 {
 412         struct dns_socket *dns_socket;
 413         struct dns_tcp_connection *dns_conn;
 414         struct tevent_req *subreq;
 415         int rc;
 416
 417         dns_conn = talloc_zero(conn, struct dns_tcp_connection);
 418         if (dns_conn == NULL) {
 419                 stream_terminate_connection(conn,
 420                                 "dns_tcp_accept: out of memory");
 421                 return;
 422         }
 423
 424         dns_conn->send_queue = tevent_queue_create(conn, "dns_tcp_accept");
 425         if (dns_conn->send_queue == NULL) {
 426                 stream_terminate_connection(conn,
 427                                 "dns_tcp_accept: out of memory");
 428                 return;
 429         }
 430
 431         dns_socket = talloc_get_type(conn->private_data, struct dns_socket);
 432
 433         TALLOC_FREE(conn->event.fde);
 434
 435         rc = tstream_bsd_existing_socket(dns_conn,
 436                         socket_get_fd(conn->socket),
 437                         &dns_conn->tstream);
 438         if (rc < 0) {
 439                 stream_terminate_connection(conn,
 440                                 "dns_tcp_accept: out of memory");
 441                 return;
 442         }
 443
 444         dns_conn->conn = conn;
 445         dns_conn->dns_socket = dns_socket;
 446         conn->private_data = dns_conn;
 447
 448         /*
 449          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 450          * packet_full_request_u16 provides the pdu length then.
 451          */
 452         subreq = tstream_read_pdu_blob_send(dns_conn,
 453                                             dns_conn->conn->event.ctx,
 454                                             dns_conn->tstream,
 455                                             2, /* initial_read_size */
 456                                             packet_full_request_u16,
 457                                             dns_conn);
 458         if (subreq == NULL) {
 459                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_accept: "
 460                                 "no memory for tstream_read_pdu_blob_send");
 461                 return;
 462         }
 463         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 464 }
 465
 466 static const struct stream_server_ops dns_tcp_stream_ops = {
 467         .name                   = "dns_tcp",
 468         .accept_connection      = dns_tcp_accept,
 469         .recv_handler           = dns_tcp_recv,
 470         .send_handler           = dns_tcp_send
 471 };
 472
 473 struct dns_udp_call {
 474         struct dns_udp_socket *sock;
 475         struct tsocket_address *src;
 476         DATA_BLOB in;
 477         DATA_BLOB out;
 478 };
 479
 480 static void dns_udp_call_process_done(struct tevent_req *subreq);
 481 static void dns_udp_call_sendto_done(struct tevent_req *subreq);
 482
 483 static void dns_udp_call_loop(struct tevent_req *subreq)
 484 {
 485         struct dns_udp_socket *sock = tevent_req_callback_data(subreq,
 486                                       struct dns_udp_socket);
 487         struct dns_server *dns = sock->dns_socket->dns;
 488         struct dns_udp_call *call;
 489         uint8_t *buf;
 490         ssize_t len;
 491         int sys_errno;
 492
 493         call = talloc(sock, struct dns_udp_call);
 494         if (call == NULL) {
 495                 talloc_free(call);
 496                 goto done;
 497         }
 498         call->sock = sock;
 499
 500         len = tdgram_recvfrom_recv(subreq, &sys_errno,
 501                                    call, &buf, &call->src);
 502         TALLOC_FREE(subreq);
 503         if (len == -1) {
 504                 talloc_free(call);
 505                 goto done;
 506         }
 507
 508         call->in.data = buf;
 509         call->in.length = len;
 510
 511         DEBUG(10,("Received DNS UDP packet of length %lu from %s\n",
 512                  (long)call->in.length,
 513                  tsocket_address_string(call->src, call)));
 514
 515         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 516                                   &call->in);
 517         if (subreq == NULL) {
 518                 TALLOC_FREE(call);
 519                 goto done;
 520         }
 521         tevent_req_set_callback(subreq, dns_udp_call_process_done, call);
 522
 523 done:
 524         subreq = tdgram_recvfrom_send(sock,
 525                                       sock->dns_socket->dns->task->event_ctx,
 526                                       sock->dgram);
 527         if (subreq == NULL) {
 528                 task_server_terminate(sock->dns_socket->dns->task,
 529                                       "no memory for tdgram_recvfrom_send",
 530                                       true);
 531                 return;
 532         }
 533         tevent_req_set_callback(subreq, dns_udp_call_loop, sock);
 534 }
 535
 536 static void dns_udp_call_process_done(struct tevent_req *subreq)
 537 {
 538         struct dns_udp_call *call = tevent_req_callback_data(
 539                 subreq, struct dns_udp_call);
 540         struct dns_udp_socket *sock = call->sock;
 541         struct dns_server *dns = sock->dns_socket->dns;
 542         WERROR err;
 543
 544         err = dns_process_recv(subreq, call, &call->out);
 545         TALLOC_FREE(subreq);
 546         if (!W_ERROR_IS_OK(err)) {
 547                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 548                 TALLOC_FREE(call);
 549                 return;
 550         }
 551
 552         subreq = tdgram_sendto_queue_send(call,
 553                                           dns->task->event_ctx,
 554                                           sock->dgram,
 555                                           sock->send_queue,
 556                                           call->out.data,
 557                                           call->out.length,
 558                                           call->src);
 559         if (subreq == NULL) {
 560                 talloc_free(call);
 561                 return;
 562         }
 563         tevent_req_set_callback(subreq, dns_udp_call_sendto_done, call);
 564
 565 }
 566 static void dns_udp_call_sendto_done(struct tevent_req *subreq)
 567 {
 568         struct dns_udp_call *call = tevent_req_callback_data(subreq,
 569                                        struct dns_udp_call);
 570         ssize_t ret;
 571         int sys_errno;
 572
 573         ret = tdgram_sendto_queue_recv(subreq, &sys_errno);
 574
 575         /* We don't care about errors */
 576
 577         talloc_free(call);
 578 }
 579
 580 /*
 581   start listening on the given address
 582 */
 583 static NTSTATUS dns_add_socket(struct dns_server *dns,
 584                                const struct model_ops *model_ops,
 585                                const char *name,
 586                                const char *address,
 587                                uint16_t port)
 588 {
 589         struct dns_socket *dns_socket;
 590         struct dns_udp_socket *dns_udp_socket;
 591         struct tevent_req *udpsubreq;
 592         NTSTATUS status;
 593         int ret;
 594
 595         dns_socket = talloc(dns, struct dns_socket);
 596         NT_STATUS_HAVE_NO_MEMORY(dns_socket);
 597
 598         dns_socket->dns = dns;
 599
 600         ret = tsocket_address_inet_from_strings(dns_socket, "ip",
 601                                                 address, port,
 602                                                 &dns_socket->local_address);
 603         if (ret != 0) {
 604                 status = map_nt_error_from_unix_common(errno);
 605                 return status;
 606         }
 607
 608         status = stream_setup_socket(dns->task,
 609                                      dns->task->event_ctx,
 610                                      dns->task->lp_ctx,
 611                                      model_ops,
 612                                      &dns_tcp_stream_ops,
 613                                      "ip", address, &port,
 614                                      lpcfg_socket_options(dns->task->lp_ctx),
 615                                      dns_socket);
 616         if (!NT_STATUS_IS_OK(status)) {
 617                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 618                          address, port, nt_errstr(status)));
 619                 talloc_free(dns_socket);
 620                 return status;
 621         }
 622
 623         dns_udp_socket = talloc(dns_socket, struct dns_udp_socket);
 624         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket);
 625
 626         dns_udp_socket->dns_socket = dns_socket;
 627
 628         ret = tdgram_inet_udp_socket(dns_socket->local_address,
 629                                      NULL,
 630                                      dns_udp_socket,
 631                                      &dns_udp_socket->dgram);
 632         if (ret != 0) {
 633                 status = map_nt_error_from_unix_common(errno);
 634                 DEBUG(0,("Failed to bind to %s:%u UDP - %s\n",
 635                          address, port, nt_errstr(status)));
 636                 return status;
 637         }
 638
 639         dns_udp_socket->send_queue = tevent_queue_create(dns_udp_socket,
 640                                                          "dns_udp_send_queue");
 641         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket->send_queue);
 642
 643         udpsubreq = tdgram_recvfrom_send(dns_udp_socket,
 644                                          dns->task->event_ctx,
 645                                          dns_udp_socket->dgram);
 646         NT_STATUS_HAVE_NO_MEMORY(udpsubreq);
 647         tevent_req_set_callback(udpsubreq, dns_udp_call_loop, dns_udp_socket);
 648
 649         return NT_STATUS_OK;
 650 }
 651
 652 /*
 653   setup our listening sockets on the configured network interfaces
 654 */
 655 static NTSTATUS dns_startup_interfaces(struct dns_server *dns, struct loadparm_context *lp_ctx,
 656                                        struct interface *ifaces)
 657 {
 658         const struct model_ops *model_ops;
 659         int num_interfaces;
 660         TALLOC_CTX *tmp_ctx = talloc_new(dns);
 661         NTSTATUS status;
 662         int i;
 663
 664         /* within the dns task we want to be a single process, so
 665            ask for the single process model ops and pass these to the
 666            stream_setup_socket() call. */
 667         model_ops = process_model_startup("single");
 668         if (!model_ops) {
 669                 DEBUG(0,("Can't find 'single' process model_ops\n"));
 670                 return NT_STATUS_INTERNAL_ERROR;
 671         }
 672
 673         num_interfaces = iface_list_count(ifaces);
 674
 675         for (i=0; i<num_interfaces; i++) {
 676                 const char *address = talloc_strdup(tmp_ctx, iface_list_n_ip(ifaces, i));
 677
 678                 status = dns_add_socket(dns, model_ops, "dns", address, DNS_SERVICE_PORT);
 679                 NT_STATUS_NOT_OK_RETURN(status);
 680         }
 681
 682         talloc_free(tmp_ctx);
 683
 684         return NT_STATUS_OK;
 685 }
 686
 687 static int dns_server_sort_zones(struct ldb_message **m1, struct ldb_message **m2)
 688 {
 689         const char *n1, *n2;
 690         size_t l1, l2;
 691
 692         n1 = ldb_msg_find_attr_as_string(*m1, "name", NULL);
 693         n2 = ldb_msg_find_attr_as_string(*m2, "name", NULL);
 694
 695         l1 = strlen(n1);
 696         l2 = strlen(n2);
 697
 698         /* If the string lengths are not equal just sort by length */
 699         if (l1 != l2) {
 700                 /* If m1 is the larger zone name, return it first */
 701                 return l2 - l1;
 702         }
 703
 704         /*TODO: We need to compare DNs here, we want the DomainDNSZones first */
 705         return 0;
 706 }
 707
 708 static void dns_task_init(struct task_server *task)
 709 {
 710         struct dns_server *dns;
 711         NTSTATUS status;
 712         struct interface *ifaces;
 713         int ret;
 714         struct ldb_result *res;
 715         static const char * const attrs[] = { "name", NULL};
 716         unsigned int i;
 717
 718         switch (lpcfg_server_role(task->lp_ctx)) {
 719         case ROLE_STANDALONE:
 720                 task_server_terminate(task, "dns: no DNS required in standalone configuration", false);
 721                 return;
 722         case ROLE_DOMAIN_MEMBER:
 723                 task_server_terminate(task, "dns: no DNS required in member server configuration", false);
 724                 return;
 725         case ROLE_DOMAIN_CONTROLLER:
 726                 /* Yes, we want a DNS */
 727                 break;
 728         }
 729
 730         load_interface_list(task, task->lp_ctx, &ifaces);
 731
 732         if (iface_list_count(ifaces) == 0) {
 733                 task_server_terminate(task, "dns: no network interfaces configured", false);
 734                 return;
 735         }
 736
 737         task_server_set_title(task, "task[dns]");
 738
 739         dns = talloc_zero(task, struct dns_server);
 740         if (dns == NULL) {
 741                 task_server_terminate(task, "dns: out of memory", true);
 742                 return;
 743         }
 744
 745         dns->task = task;
 746
 747         dns->samdb = samdb_connect(dns, dns->task->event_ctx, dns->task->lp_ctx,
 748                               system_session(dns->task->lp_ctx), 0);
 749         if (!dns->samdb) {
 750                 task_server_terminate(task, "dns: samdb_connect failed", true);
 751                 return;
 752         }
 753
 754         // TODO: this search does not work against windows
 755         ret = dsdb_search(dns->samdb, dns, &res, NULL, LDB_SCOPE_SUBTREE,
 756                           attrs, DSDB_SEARCH_SEARCH_ALL_PARTITIONS, "(objectClass=dnsZone)");
 757         if (ret != LDB_SUCCESS) {
 758                 task_server_terminate(task,
 759                                       "dns: failed to look up root DNS zones",
 760                                       true);
 761                 return;
 762         }
 763
 764         TYPESAFE_QSORT(res->msgs, res->count, dns_server_sort_zones);
 765
 766         for (i=0; i < res->count; i++) {
 767                 struct dns_server_zone *z;
 768
 769                 z = talloc_zero(dns, struct dns_server_zone);
 770                 if (z == NULL) {
 771                 }
 772
 773                 z->name = ldb_msg_find_attr_as_string(res->msgs[i], "name", NULL);
 774                 z->dn = talloc_move(z, &res->msgs[i]->dn);
 775
 776                 DLIST_ADD_END(dns->zones, z, NULL);
 777         }
 778
 779         status = dns_startup_interfaces(dns, task->lp_ctx, ifaces);
 780         if (!NT_STATUS_IS_OK(status)) {
 781                 task_server_terminate(task, "dns failed to setup interfaces", true);
 782                 return;
 783         }
 784 }
 785
 786 NTSTATUS server_service_dns_init(void)
 787 {
 788         return register_server_service("dns", dns_task_init);
 789 }