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 #include "auth/auth.h"
  47 #include "auth/credentials/credentials.h"
  48
  49 NTSTATUS server_service_dns_init(void);
  50
  51 /* hold information about one dns socket */
  52 struct dns_socket {
  53         struct dns_server *dns;
  54         struct tsocket_address *local_address;
  55 };
  56
  57 struct dns_udp_socket {
  58         struct dns_socket *dns_socket;
  59         struct tdgram_context *dgram;
  60         struct tevent_queue *send_queue;
  61 };
  62
  63 /*
  64   state of an open tcp connection
  65 */
  66 struct dns_tcp_connection {
  67         /* stream connection we belong to */
  68         struct stream_connection *conn;
  69
  70         /* the dns_server the connection belongs to */
  71         struct dns_socket *dns_socket;
  72
  73         struct tstream_context *tstream;
  74
  75         struct tevent_queue *send_queue;
  76 };
  77
  78 static void dns_tcp_terminate_connection(struct dns_tcp_connection *dnsconn, const char *reason)
  79 {
  80         stream_terminate_connection(dnsconn->conn, reason);
  81 }
  82
  83 static void dns_tcp_recv(struct stream_connection *conn, uint16_t flags)
  84 {
  85         struct dns_tcp_connection *dnsconn = talloc_get_type(conn->private_data,
  86                                                              struct dns_tcp_connection);
  87         /* this should never be triggered! */
  88         dns_tcp_terminate_connection(dnsconn, "dns_tcp_recv: called");
  89 }
  90
  91 static void dns_tcp_send(struct stream_connection *conn, uint16_t flags)
  92 {
  93         struct dns_tcp_connection *dnsconn = talloc_get_type(conn->private_data,
  94                                                              struct dns_tcp_connection);
  95         /* this should never be triggered! */
  96         dns_tcp_terminate_connection(dnsconn, "dns_tcp_send: called");
  97 }
  98
  99 struct dns_process_state {
 100         DATA_BLOB *in;
 101         struct dns_server *dns;
 102         struct dns_name_packet in_packet;
 103         struct dns_request_state state;
 104         uint16_t dns_err;
 105         struct dns_name_packet out_packet;
 106         DATA_BLOB out;
 107 };
 108
 109 static void dns_process_done(struct tevent_req *subreq);
 110
 111 static struct tevent_req *dns_process_send(TALLOC_CTX *mem_ctx,
 112                                            struct tevent_context *ev,
 113                                            struct dns_server *dns,
 114                                            DATA_BLOB *in)
 115 {
 116         struct tevent_req *req, *subreq;
 117         struct dns_process_state *state;
 118         enum ndr_err_code ndr_err;
 119         WERROR ret;
 120
 121         req = tevent_req_create(mem_ctx, &state, struct dns_process_state);
 122         if (req == NULL) {
 123                 return NULL;
 124         }
 125         state->in = in;
 126
 127         state->dns = dns;
 128
 129         if (in->length < 12) {
 130                 tevent_req_werror(req, WERR_INVALID_PARAM);
 131                 return tevent_req_post(req, ev);
 132         }
 133         dump_data(8, in->data, in->length);
 134
 135         ndr_err = ndr_pull_struct_blob(
 136                 in, state, &state->in_packet,
 137                 (ndr_pull_flags_fn_t)ndr_pull_dns_name_packet);
 138
 139         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 140                 state->dns_err = DNS_RCODE_FORMERR;
 141                 tevent_req_done(req);
 142                 return tevent_req_post(req, ev);
 143         }
 144         if (DEBUGLVL(8)) {
 145                 NDR_PRINT_DEBUG(dns_name_packet, &state->in_packet);
 146         }
 147
 148         ret = dns_verify_tsig(dns, state, &state->state, &state->in_packet);
 149         if (!W_ERROR_IS_OK(ret)) {
 150                 DEBUG(0, ("Bailing out early!\n"));
 151                 state->dns_err = werr_to_dns_err(ret);
 152                 tevent_req_done(req);
 153                 return tevent_req_post(req, ev);
 154         }
 155
 156         state->state.flags = state->in_packet.operation;
 157         state->state.flags |= DNS_FLAG_REPLY;
 158
 159         if (lpcfg_dns_recursive_queries(dns->task->lp_ctx)) {
 160                 state->state.flags |= DNS_FLAG_RECURSION_AVAIL;
 161         }
 162
 163         state->out_packet = state->in_packet;
 164
 165         switch (state->in_packet.operation & DNS_OPCODE) {
 166         case DNS_OPCODE_QUERY:
 167                 subreq = dns_server_process_query_send(
 168                         state, ev, dns, &state->state, &state->in_packet);
 169                 if (tevent_req_nomem(subreq, req)) {
 170                         return tevent_req_post(req, ev);
 171                 }
 172                 tevent_req_set_callback(subreq, dns_process_done, req);
 173                 return req;
 174         case DNS_OPCODE_UPDATE:
 175                 ret = dns_server_process_update(
 176                         dns, &state->state, state, &state->in_packet,
 177                         &state->out_packet.answers, &state->out_packet.ancount,
 178                         &state->out_packet.nsrecs,  &state->out_packet.nscount,
 179                         &state->out_packet.additional,
 180                         &state->out_packet.arcount);
 181                 break;
 182         default:
 183                 ret = WERR_DNS_ERROR_RCODE_NOT_IMPLEMENTED;
 184         }
 185         if (!W_ERROR_IS_OK(ret)) {
 186                 state->dns_err = werr_to_dns_err(ret);
 187         }
 188         tevent_req_done(req);
 189         return tevent_req_post(req, ev);
 190 }
 191
 192 static void dns_process_done(struct tevent_req *subreq)
 193 {
 194         struct tevent_req *req = tevent_req_callback_data(
 195                 subreq, struct tevent_req);
 196         struct dns_process_state *state = tevent_req_data(
 197                 req, struct dns_process_state);
 198         WERROR ret;
 199
 200         ret = dns_server_process_query_recv(
 201                 subreq, state,
 202                 &state->out_packet.answers, &state->out_packet.ancount,
 203                 &state->out_packet.nsrecs,  &state->out_packet.nscount,
 204                 &state->out_packet.additional, &state->out_packet.arcount);
 205         TALLOC_FREE(subreq);
 206
 207         if (!W_ERROR_IS_OK(ret)) {
 208                 state->dns_err = werr_to_dns_err(ret);
 209         }
 210         tevent_req_done(req);
 211 }
 212
 213 static WERROR dns_process_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 214                                DATA_BLOB *out)
 215 {
 216         struct dns_process_state *state = tevent_req_data(
 217                 req, struct dns_process_state);
 218         enum ndr_err_code ndr_err;
 219         WERROR ret;
 220
 221         if (tevent_req_is_werror(req, &ret)) {
 222                 return ret;
 223         }
 224         if (state->dns_err != DNS_RCODE_OK) {
 225                 goto drop;
 226         }
 227         state->out_packet.operation |= state->state.flags;
 228
 229         if (state->state.sign) {
 230                 ret = dns_sign_tsig(state->dns, mem_ctx, &state->state,
 231                                     &state->out_packet, 0);
 232                 if (!W_ERROR_IS_OK(ret)) {
 233                         state->dns_err = DNS_RCODE_SERVFAIL;
 234                         goto drop;
 235                 }
 236         }
 237
 238         ndr_err = ndr_push_struct_blob(
 239                 out, mem_ctx, &state->out_packet,
 240                 (ndr_push_flags_fn_t)ndr_push_dns_name_packet);
 241         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 242                 DEBUG(1, ("Failed to push packet: %s!\n",
 243                           ndr_errstr(ndr_err)));
 244                 state->dns_err = DNS_RCODE_SERVFAIL;
 245                 goto drop;
 246         }
 247         return WERR_OK;
 248
 249 drop:
 250         *out = data_blob_talloc(mem_ctx, state->in->data, state->in->length);
 251         if (out->data == NULL) {
 252                 return WERR_NOMEM;
 253         }
 254         out->data[2] |= 0x80; /* Toggle DNS_FLAG_REPLY */
 255         out->data[3] |= state->dns_err;
 256         return WERR_OK;
 257 }
 258
 259 struct dns_tcp_call {
 260         struct dns_tcp_connection *dns_conn;
 261         DATA_BLOB in;
 262         DATA_BLOB out;
 263         uint8_t out_hdr[4];
 264         struct iovec out_iov[2];
 265 };
 266
 267 static void dns_tcp_call_process_done(struct tevent_req *subreq);
 268 static void dns_tcp_call_writev_done(struct tevent_req *subreq);
 269
 270 static void dns_tcp_call_loop(struct tevent_req *subreq)
 271 {
 272         struct dns_tcp_connection *dns_conn = tevent_req_callback_data(subreq,
 273                                       struct dns_tcp_connection);
 274         struct dns_server *dns = dns_conn->dns_socket->dns;
 275         struct dns_tcp_call *call;
 276         NTSTATUS status;
 277
 278         call = talloc(dns_conn, struct dns_tcp_call);
 279         if (call == NULL) {
 280                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 281                                 "no memory for dns_tcp_call");
 282                 return;
 283         }
 284         call->dns_conn = dns_conn;
 285
 286         status = tstream_read_pdu_blob_recv(subreq,
 287                                             call,
 288                                             &call->in);
 289         TALLOC_FREE(subreq);
 290         if (!NT_STATUS_IS_OK(status)) {
 291                 const char *reason;
 292
 293                 reason = talloc_asprintf(call, "dns_tcp_call_loop: "
 294                                          "tstream_read_pdu_blob_recv() - %s",
 295                                          nt_errstr(status));
 296                 if (!reason) {
 297                         reason = nt_errstr(status);
 298                 }
 299
 300                 dns_tcp_terminate_connection(dns_conn, reason);
 301                 return;
 302         }
 303
 304         DEBUG(10,("Received DNS TCP packet of length %lu from %s\n",
 305                  (long) call->in.length,
 306                  tsocket_address_string(dns_conn->conn->remote_address, call)));
 307
 308         /* skip length header */
 309         call->in.data += 2;
 310         call->in.length -= 2;
 311
 312         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 313                                   &call->in);
 314         if (subreq == NULL) {
 315                 dns_tcp_terminate_connection(
 316                         dns_conn, "dns_tcp_call_loop: dns_process_send "
 317                         "failed\n");
 318                 return;
 319         }
 320         tevent_req_set_callback(subreq, dns_tcp_call_process_done, call);
 321
 322         /*
 323          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 324          * packet_full_request_u16 provides the pdu length then.
 325          */
 326         subreq = tstream_read_pdu_blob_send(dns_conn,
 327                                             dns_conn->conn->event.ctx,
 328                                             dns_conn->tstream,
 329                                             2, /* initial_read_size */
 330                                             packet_full_request_u16,
 331                                             dns_conn);
 332         if (subreq == NULL) {
 333                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 334                                 "no memory for tstream_read_pdu_blob_send");
 335                 return;
 336         }
 337         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 338 }
 339
 340 static void dns_tcp_call_process_done(struct tevent_req *subreq)
 341 {
 342         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 343                         struct dns_tcp_call);
 344         struct dns_tcp_connection *dns_conn = call->dns_conn;
 345         WERROR err;
 346
 347         err = dns_process_recv(subreq, call, &call->out);
 348         TALLOC_FREE(subreq);
 349         if (!W_ERROR_IS_OK(err)) {
 350                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 351                 dns_tcp_terminate_connection(dns_conn,
 352                                 "dns_tcp_call_loop: process function failed");
 353                 return;
 354         }
 355
 356         /* First add the length of the out buffer */
 357         RSSVAL(call->out_hdr, 0, call->out.length);
 358         call->out_iov[0].iov_base = (char *) call->out_hdr;
 359         call->out_iov[0].iov_len = 2;
 360
 361         call->out_iov[1].iov_base = (char *) call->out.data;
 362         call->out_iov[1].iov_len = call->out.length;
 363
 364         subreq = tstream_writev_queue_send(call,
 365                                            dns_conn->conn->event.ctx,
 366                                            dns_conn->tstream,
 367                                            dns_conn->send_queue,
 368                                            call->out_iov, 2);
 369         if (subreq == NULL) {
 370                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 371                                 "no memory for tstream_writev_queue_send");
 372                 return;
 373         }
 374         tevent_req_set_callback(subreq, dns_tcp_call_writev_done, call);
 375 }
 376
 377 static void dns_tcp_call_writev_done(struct tevent_req *subreq)
 378 {
 379         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 380                         struct dns_tcp_call);
 381         int sys_errno;
 382         int rc;
 383
 384         rc = tstream_writev_queue_recv(subreq, &sys_errno);
 385         TALLOC_FREE(subreq);
 386         if (rc == -1) {
 387                 const char *reason;
 388
 389                 reason = talloc_asprintf(call, "dns_tcp_call_writev_done: "
 390                                          "tstream_writev_queue_recv() - %d:%s",
 391                                          sys_errno, strerror(sys_errno));
 392                 if (!reason) {
 393                         reason = "dns_tcp_call_writev_done: tstream_writev_queue_recv() failed";
 394                 }
 395
 396                 dns_tcp_terminate_connection(call->dns_conn, reason);
 397                 return;
 398         }
 399
 400         /* We don't care about errors */
 401
 402         talloc_free(call);
 403 }
 404
 405 /*
 406   called when we get a new connection
 407 */
 408 static void dns_tcp_accept(struct stream_connection *conn)
 409 {
 410         struct dns_socket *dns_socket;
 411         struct dns_tcp_connection *dns_conn;
 412         struct tevent_req *subreq;
 413         int rc;
 414
 415         dns_conn = talloc_zero(conn, struct dns_tcp_connection);
 416         if (dns_conn == NULL) {
 417                 stream_terminate_connection(conn,
 418                                 "dns_tcp_accept: out of memory");
 419                 return;
 420         }
 421
 422         dns_conn->send_queue = tevent_queue_create(conn, "dns_tcp_accept");
 423         if (dns_conn->send_queue == NULL) {
 424                 stream_terminate_connection(conn,
 425                                 "dns_tcp_accept: out of memory");
 426                 return;
 427         }
 428
 429         dns_socket = talloc_get_type(conn->private_data, struct dns_socket);
 430
 431         TALLOC_FREE(conn->event.fde);
 432
 433         rc = tstream_bsd_existing_socket(dns_conn,
 434                         socket_get_fd(conn->socket),
 435                         &dns_conn->tstream);
 436         if (rc < 0) {
 437                 stream_terminate_connection(conn,
 438                                 "dns_tcp_accept: out of memory");
 439                 return;
 440         }
 441
 442         dns_conn->conn = conn;
 443         dns_conn->dns_socket = dns_socket;
 444         conn->private_data = dns_conn;
 445
 446         /*
 447          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 448          * packet_full_request_u16 provides the pdu length then.
 449          */
 450         subreq = tstream_read_pdu_blob_send(dns_conn,
 451                                             dns_conn->conn->event.ctx,
 452                                             dns_conn->tstream,
 453                                             2, /* initial_read_size */
 454                                             packet_full_request_u16,
 455                                             dns_conn);
 456         if (subreq == NULL) {
 457                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_accept: "
 458                                 "no memory for tstream_read_pdu_blob_send");
 459                 return;
 460         }
 461         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 462 }
 463
 464 static const struct stream_server_ops dns_tcp_stream_ops = {
 465         .name                   = "dns_tcp",
 466         .accept_connection      = dns_tcp_accept,
 467         .recv_handler           = dns_tcp_recv,
 468         .send_handler           = dns_tcp_send
 469 };
 470
 471 struct dns_udp_call {
 472         struct dns_udp_socket *sock;
 473         struct tsocket_address *src;
 474         DATA_BLOB in;
 475         DATA_BLOB out;
 476 };
 477
 478 static void dns_udp_call_process_done(struct tevent_req *subreq);
 479 static void dns_udp_call_sendto_done(struct tevent_req *subreq);
 480
 481 static void dns_udp_call_loop(struct tevent_req *subreq)
 482 {
 483         struct dns_udp_socket *sock = tevent_req_callback_data(subreq,
 484                                       struct dns_udp_socket);
 485         struct dns_server *dns = sock->dns_socket->dns;
 486         struct dns_udp_call *call;
 487         uint8_t *buf;
 488         ssize_t len;
 489         int sys_errno;
 490
 491         call = talloc(sock, struct dns_udp_call);
 492         if (call == NULL) {
 493                 talloc_free(call);
 494                 goto done;
 495         }
 496         call->sock = sock;
 497
 498         len = tdgram_recvfrom_recv(subreq, &sys_errno,
 499                                    call, &buf, &call->src);
 500         TALLOC_FREE(subreq);
 501         if (len == -1) {
 502                 talloc_free(call);
 503                 goto done;
 504         }
 505
 506         call->in.data = buf;
 507         call->in.length = len;
 508
 509         DEBUG(10,("Received DNS UDP packet of length %lu from %s\n",
 510                  (long)call->in.length,
 511                  tsocket_address_string(call->src, call)));
 512
 513         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 514                                   &call->in);
 515         if (subreq == NULL) {
 516                 TALLOC_FREE(call);
 517                 goto done;
 518         }
 519         tevent_req_set_callback(subreq, dns_udp_call_process_done, call);
 520
 521 done:
 522         subreq = tdgram_recvfrom_send(sock,
 523                                       sock->dns_socket->dns->task->event_ctx,
 524                                       sock->dgram);
 525         if (subreq == NULL) {
 526                 task_server_terminate(sock->dns_socket->dns->task,
 527                                       "no memory for tdgram_recvfrom_send",
 528                                       true);
 529                 return;
 530         }
 531         tevent_req_set_callback(subreq, dns_udp_call_loop, sock);
 532 }
 533
 534 static void dns_udp_call_process_done(struct tevent_req *subreq)
 535 {
 536         struct dns_udp_call *call = tevent_req_callback_data(
 537                 subreq, struct dns_udp_call);
 538         struct dns_udp_socket *sock = call->sock;
 539         struct dns_server *dns = sock->dns_socket->dns;
 540         WERROR err;
 541
 542         err = dns_process_recv(subreq, call, &call->out);
 543         TALLOC_FREE(subreq);
 544         if (!W_ERROR_IS_OK(err)) {
 545                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 546                 TALLOC_FREE(call);
 547                 return;
 548         }
 549
 550         subreq = tdgram_sendto_queue_send(call,
 551                                           dns->task->event_ctx,
 552                                           sock->dgram,
 553                                           sock->send_queue,
 554                                           call->out.data,
 555                                           call->out.length,
 556                                           call->src);
 557         if (subreq == NULL) {
 558                 talloc_free(call);
 559                 return;
 560         }
 561         tevent_req_set_callback(subreq, dns_udp_call_sendto_done, call);
 562
 563 }
 564 static void dns_udp_call_sendto_done(struct tevent_req *subreq)
 565 {
 566         struct dns_udp_call *call = tevent_req_callback_data(subreq,
 567                                        struct dns_udp_call);
 568         ssize_t ret;
 569         int sys_errno;
 570
 571         ret = tdgram_sendto_queue_recv(subreq, &sys_errno);
 572
 573         /* We don't care about errors */
 574
 575         talloc_free(call);
 576 }
 577
 578 /*
 579   start listening on the given address
 580 */
 581 static NTSTATUS dns_add_socket(struct dns_server *dns,
 582                                const struct model_ops *model_ops,
 583                                const char *name,
 584                                const char *address,
 585                                uint16_t port)
 586 {
 587         struct dns_socket *dns_socket;
 588         struct dns_udp_socket *dns_udp_socket;
 589         struct tevent_req *udpsubreq;
 590         NTSTATUS status;
 591         int ret;
 592
 593         dns_socket = talloc(dns, struct dns_socket);
 594         NT_STATUS_HAVE_NO_MEMORY(dns_socket);
 595
 596         dns_socket->dns = dns;
 597
 598         ret = tsocket_address_inet_from_strings(dns_socket, "ip",
 599                                                 address, port,
 600                                                 &dns_socket->local_address);
 601         if (ret != 0) {
 602                 status = map_nt_error_from_unix_common(errno);
 603                 return status;
 604         }
 605
 606         status = stream_setup_socket(dns->task,
 607                                      dns->task->event_ctx,
 608                                      dns->task->lp_ctx,
 609                                      model_ops,
 610                                      &dns_tcp_stream_ops,
 611                                      "ip", address, &port,
 612                                      lpcfg_socket_options(dns->task->lp_ctx),
 613                                      dns_socket);
 614         if (!NT_STATUS_IS_OK(status)) {
 615                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 616                          address, port, nt_errstr(status)));
 617                 talloc_free(dns_socket);
 618                 return status;
 619         }
 620
 621         dns_udp_socket = talloc(dns_socket, struct dns_udp_socket);
 622         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket);
 623
 624         dns_udp_socket->dns_socket = dns_socket;
 625
 626         ret = tdgram_inet_udp_socket(dns_socket->local_address,
 627                                      NULL,
 628                                      dns_udp_socket,
 629                                      &dns_udp_socket->dgram);
 630         if (ret != 0) {
 631                 status = map_nt_error_from_unix_common(errno);
 632                 DEBUG(0,("Failed to bind to %s:%u UDP - %s\n",
 633                          address, port, nt_errstr(status)));
 634                 return status;
 635         }
 636
 637         dns_udp_socket->send_queue = tevent_queue_create(dns_udp_socket,
 638                                                          "dns_udp_send_queue");
 639         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket->send_queue);
 640
 641         udpsubreq = tdgram_recvfrom_send(dns_udp_socket,
 642                                          dns->task->event_ctx,
 643                                          dns_udp_socket->dgram);
 644         NT_STATUS_HAVE_NO_MEMORY(udpsubreq);
 645         tevent_req_set_callback(udpsubreq, dns_udp_call_loop, dns_udp_socket);
 646
 647         return NT_STATUS_OK;
 648 }
 649
 650 /*
 651   setup our listening sockets on the configured network interfaces
 652 */
 653 static NTSTATUS dns_startup_interfaces(struct dns_server *dns, struct loadparm_context *lp_ctx,
 654                                        struct interface *ifaces)
 655 {
 656         const struct model_ops *model_ops;
 657         int num_interfaces;
 658         TALLOC_CTX *tmp_ctx = talloc_new(dns);
 659         NTSTATUS status;
 660         int i;
 661
 662         /* within the dns task we want to be a single process, so
 663            ask for the single process model ops and pass these to the
 664            stream_setup_socket() call. */
 665         model_ops = process_model_startup("single");
 666         if (!model_ops) {
 667                 DEBUG(0,("Can't find 'single' process model_ops\n"));
 668                 return NT_STATUS_INTERNAL_ERROR;
 669         }
 670
 671         num_interfaces = iface_list_count(ifaces);
 672
 673         for (i=0; i<num_interfaces; i++) {
 674                 const char *address = talloc_strdup(tmp_ctx, iface_list_n_ip(ifaces, i));
 675
 676                 status = dns_add_socket(dns, model_ops, "dns", address, DNS_SERVICE_PORT);
 677                 NT_STATUS_NOT_OK_RETURN(status);
 678         }
 679
 680         talloc_free(tmp_ctx);
 681
 682         return NT_STATUS_OK;
 683 }
 684
 685 static int dns_server_sort_zones(struct ldb_message **m1, struct ldb_message **m2)
 686 {
 687         const char *n1, *n2;
 688         size_t l1, l2;
 689
 690         n1 = ldb_msg_find_attr_as_string(*m1, "name", NULL);
 691         n2 = ldb_msg_find_attr_as_string(*m2, "name", NULL);
 692
 693         l1 = strlen(n1);
 694         l2 = strlen(n2);
 695
 696         /* If the string lengths are not equal just sort by length */
 697         if (l1 != l2) {
 698                 /* If m1 is the larger zone name, return it first */
 699                 return l2 - l1;
 700         }
 701
 702         /*TODO: We need to compare DNs here, we want the DomainDNSZones first */
 703         return 0;
 704 }
 705
 706 static struct dns_server_tkey_store *tkey_store_init(TALLOC_CTX *mem_ctx,
 707                                                      uint16_t size)
 708 {
 709         struct dns_server_tkey_store *buffer = talloc_zero(mem_ctx,
 710                                                 struct dns_server_tkey_store);
 711
 712         if (buffer == NULL) {
 713                 return NULL;
 714         }
 715
 716         buffer->size = size;
 717         buffer->next_idx = 0;
 718
 719         buffer->tkeys = talloc_zero_array(buffer, struct dns_server_tkey *, size);
 720         if (buffer->tkeys == NULL) {
 721                 TALLOC_FREE(buffer);
 722         }
 723
 724         return buffer;
 725 }
 726
 727 static void dns_task_init(struct task_server *task)
 728 {
 729         struct dns_server *dns;
 730         NTSTATUS status;
 731         struct interface *ifaces;
 732         int ret;
 733         struct ldb_result *res;
 734         static const char * const attrs[] = { "name", NULL};
 735         unsigned int i;
 736
 737         switch (lpcfg_server_role(task->lp_ctx)) {
 738         case ROLE_STANDALONE:
 739                 task_server_terminate(task, "dns: no DNS required in standalone configuration", false);
 740                 return;
 741         case ROLE_DOMAIN_MEMBER:
 742                 task_server_terminate(task, "dns: no DNS required in member server configuration", false);
 743                 return;
 744         case ROLE_ACTIVE_DIRECTORY_DC:
 745                 /* Yes, we want a DNS */
 746                 break;
 747         }
 748
 749         load_interface_list(task, task->lp_ctx, &ifaces);
 750
 751         if (iface_list_count(ifaces) == 0) {
 752                 task_server_terminate(task, "dns: no network interfaces configured", false);
 753                 return;
 754         }
 755
 756         task_server_set_title(task, "task[dns]");
 757
 758         dns = talloc_zero(task, struct dns_server);
 759         if (dns == NULL) {
 760                 task_server_terminate(task, "dns: out of memory", true);
 761                 return;
 762         }
 763
 764         dns->task = task;
 765
 766         dns->server_credentials = cli_credentials_init(dns);
 767         if (!dns->server_credentials) {
 768                 task_server_terminate(task, "Failed to init server credentials\n", true);
 769                 return;
 770         }
 771
 772         cli_credentials_set_conf(dns->server_credentials, task->lp_ctx);
 773         status = cli_credentials_set_machine_account(dns->server_credentials, task->lp_ctx);
 774         if (!NT_STATUS_IS_OK(status)) {
 775                 task_server_terminate(task,
 776                         talloc_asprintf(task, "Failed to obtain server credentials, perhaps a standalone server?: %s\n",
 777                                         nt_errstr(status)),
 778                         true);
 779                 return;
 780         }
 781
 782         dns->tkeys = tkey_store_init(dns, TKEY_BUFFER_SIZE);
 783         if (!dns->tkeys) {
 784                 task_server_terminate(task, "Failed to allocate tkey storage\n", true);
 785                 return;
 786         }
 787
 788         dns->samdb = samdb_connect(dns, dns->task->event_ctx, dns->task->lp_ctx,
 789                               system_session(dns->task->lp_ctx), 0);
 790         if (!dns->samdb) {
 791                 task_server_terminate(task, "dns: samdb_connect failed", true);
 792                 return;
 793         }
 794
 795         // TODO: this search does not work against windows
 796         ret = dsdb_search(dns->samdb, dns, &res, NULL, LDB_SCOPE_SUBTREE,
 797                           attrs, DSDB_SEARCH_SEARCH_ALL_PARTITIONS, "(objectClass=dnsZone)");
 798         if (ret != LDB_SUCCESS) {
 799                 task_server_terminate(task,
 800                                       "dns: failed to look up root DNS zones",
 801                                       true);
 802                 return;
 803         }
 804
 805         TYPESAFE_QSORT(res->msgs, res->count, dns_server_sort_zones);
 806
 807         for (i=0; i < res->count; i++) {
 808                 struct dns_server_zone *z;
 809
 810                 z = talloc_zero(dns, struct dns_server_zone);
 811                 if (z == NULL) {
 812                 }
 813
 814                 z->name = ldb_msg_find_attr_as_string(res->msgs[i], "name", NULL);
 815                 z->dn = talloc_move(z, &res->msgs[i]->dn);
 816
 817                 DLIST_ADD_END(dns->zones, z, NULL);
 818         }
 819
 820         status = dns_startup_interfaces(dns, task->lp_ctx, ifaces);
 821         if (!NT_STATUS_IS_OK(status)) {
 822                 task_server_terminate(task, "dns failed to setup interfaces", true);
 823                 return;
 824         }
 825 }
 826
 827 NTSTATUS server_service_dns_init(void)
 828 {
 829         return register_server_service("dns", dns_task_init);
 830 }