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         const char *forwarder = lpcfg_dns_forwarder(dns->task->lp_ctx);
 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, in);
 149         if (!W_ERROR_IS_OK(ret)) {
 150                 DEBUG(1, ("Failed to verify TSIG!\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
 160         if (forwarder && *forwarder) {
 161                 state->state.flags |= DNS_FLAG_RECURSION_AVAIL;
 162         }
 163
 164         state->out_packet = state->in_packet;
 165
 166         switch (state->in_packet.operation & DNS_OPCODE) {
 167         case DNS_OPCODE_QUERY:
 168                 subreq = dns_server_process_query_send(
 169                         state, ev, dns, &state->state, &state->in_packet);
 170                 if (tevent_req_nomem(subreq, req)) {
 171                         return tevent_req_post(req, ev);
 172                 }
 173                 tevent_req_set_callback(subreq, dns_process_done, req);
 174                 return req;
 175         case DNS_OPCODE_UPDATE:
 176                 ret = dns_server_process_update(
 177                         dns, &state->state, state, &state->in_packet,
 178                         &state->out_packet.answers, &state->out_packet.ancount,
 179                         &state->out_packet.nsrecs,  &state->out_packet.nscount,
 180                         &state->out_packet.additional,
 181                         &state->out_packet.arcount);
 182                 break;
 183         default:
 184                 ret = WERR_DNS_ERROR_RCODE_NOT_IMPLEMENTED;
 185         }
 186         if (!W_ERROR_IS_OK(ret)) {
 187                 state->dns_err = werr_to_dns_err(ret);
 188         }
 189         tevent_req_done(req);
 190         return tevent_req_post(req, ev);
 191 }
 192
 193 static void dns_process_done(struct tevent_req *subreq)
 194 {
 195         struct tevent_req *req = tevent_req_callback_data(
 196                 subreq, struct tevent_req);
 197         struct dns_process_state *state = tevent_req_data(
 198                 req, struct dns_process_state);
 199         WERROR ret;
 200
 201         ret = dns_server_process_query_recv(
 202                 subreq, state,
 203                 &state->out_packet.answers, &state->out_packet.ancount,
 204                 &state->out_packet.nsrecs,  &state->out_packet.nscount,
 205                 &state->out_packet.additional, &state->out_packet.arcount);
 206         TALLOC_FREE(subreq);
 207
 208         if (!W_ERROR_IS_OK(ret)) {
 209                 state->dns_err = werr_to_dns_err(ret);
 210         }
 211         tevent_req_done(req);
 212 }
 213
 214 static WERROR dns_process_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 215                                DATA_BLOB *out)
 216 {
 217         struct dns_process_state *state = tevent_req_data(
 218                 req, struct dns_process_state);
 219         enum ndr_err_code ndr_err;
 220         WERROR ret;
 221
 222         if (tevent_req_is_werror(req, &ret)) {
 223                 return ret;
 224         }
 225         if (state->dns_err != DNS_RCODE_OK) {
 226                 goto drop;
 227         }
 228         state->out_packet.operation |= state->state.flags;
 229
 230         if (state->state.sign) {
 231                 ret = dns_sign_tsig(state->dns, mem_ctx, &state->state,
 232                                     &state->out_packet, 0);
 233                 if (!W_ERROR_IS_OK(ret)) {
 234                         state->dns_err = DNS_RCODE_SERVFAIL;
 235                         goto drop;
 236                 }
 237         }
 238
 239         ndr_err = ndr_push_struct_blob(
 240                 out, mem_ctx, &state->out_packet,
 241                 (ndr_push_flags_fn_t)ndr_push_dns_name_packet);
 242         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 243                 DEBUG(1, ("Failed to push packet: %s!\n",
 244                           ndr_errstr(ndr_err)));
 245                 state->dns_err = DNS_RCODE_SERVFAIL;
 246                 goto drop;
 247         }
 248         return WERR_OK;
 249
 250 drop:
 251         *out = data_blob_talloc(mem_ctx, state->in->data, state->in->length);
 252         if (out->data == NULL) {
 253                 return WERR_NOMEM;
 254         }
 255         out->data[2] |= 0x80; /* Toggle DNS_FLAG_REPLY */
 256         out->data[3] |= state->dns_err;
 257         return WERR_OK;
 258 }
 259
 260 struct dns_tcp_call {
 261         struct dns_tcp_connection *dns_conn;
 262         DATA_BLOB in;
 263         DATA_BLOB out;
 264         uint8_t out_hdr[4];
 265         struct iovec out_iov[2];
 266 };
 267
 268 static void dns_tcp_call_process_done(struct tevent_req *subreq);
 269 static void dns_tcp_call_writev_done(struct tevent_req *subreq);
 270
 271 static void dns_tcp_call_loop(struct tevent_req *subreq)
 272 {
 273         struct dns_tcp_connection *dns_conn = tevent_req_callback_data(subreq,
 274                                       struct dns_tcp_connection);
 275         struct dns_server *dns = dns_conn->dns_socket->dns;
 276         struct dns_tcp_call *call;
 277         NTSTATUS status;
 278
 279         call = talloc(dns_conn, struct dns_tcp_call);
 280         if (call == NULL) {
 281                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 282                                 "no memory for dns_tcp_call");
 283                 return;
 284         }
 285         call->dns_conn = dns_conn;
 286
 287         status = tstream_read_pdu_blob_recv(subreq,
 288                                             call,
 289                                             &call->in);
 290         TALLOC_FREE(subreq);
 291         if (!NT_STATUS_IS_OK(status)) {
 292                 const char *reason;
 293
 294                 reason = talloc_asprintf(call, "dns_tcp_call_loop: "
 295                                          "tstream_read_pdu_blob_recv() - %s",
 296                                          nt_errstr(status));
 297                 if (!reason) {
 298                         reason = nt_errstr(status);
 299                 }
 300
 301                 dns_tcp_terminate_connection(dns_conn, reason);
 302                 return;
 303         }
 304
 305         DEBUG(10,("Received DNS TCP packet of length %lu from %s\n",
 306                  (long) call->in.length,
 307                  tsocket_address_string(dns_conn->conn->remote_address, call)));
 308
 309         /* skip length header */
 310         call->in.data += 2;
 311         call->in.length -= 2;
 312
 313         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 314                                   &call->in);
 315         if (subreq == NULL) {
 316                 dns_tcp_terminate_connection(
 317                         dns_conn, "dns_tcp_call_loop: dns_process_send "
 318                         "failed\n");
 319                 return;
 320         }
 321         tevent_req_set_callback(subreq, dns_tcp_call_process_done, call);
 322
 323         /*
 324          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 325          * packet_full_request_u16 provides the pdu length then.
 326          */
 327         subreq = tstream_read_pdu_blob_send(dns_conn,
 328                                             dns_conn->conn->event.ctx,
 329                                             dns_conn->tstream,
 330                                             2, /* initial_read_size */
 331                                             packet_full_request_u16,
 332                                             dns_conn);
 333         if (subreq == NULL) {
 334                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 335                                 "no memory for tstream_read_pdu_blob_send");
 336                 return;
 337         }
 338         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 339 }
 340
 341 static void dns_tcp_call_process_done(struct tevent_req *subreq)
 342 {
 343         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 344                         struct dns_tcp_call);
 345         struct dns_tcp_connection *dns_conn = call->dns_conn;
 346         WERROR err;
 347
 348         err = dns_process_recv(subreq, call, &call->out);
 349         TALLOC_FREE(subreq);
 350         if (!W_ERROR_IS_OK(err)) {
 351                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 352                 dns_tcp_terminate_connection(dns_conn,
 353                                 "dns_tcp_call_loop: process function failed");
 354                 return;
 355         }
 356
 357         /* First add the length of the out buffer */
 358         RSSVAL(call->out_hdr, 0, call->out.length);
 359         call->out_iov[0].iov_base = (char *) call->out_hdr;
 360         call->out_iov[0].iov_len = 2;
 361
 362         call->out_iov[1].iov_base = (char *) call->out.data;
 363         call->out_iov[1].iov_len = call->out.length;
 364
 365         subreq = tstream_writev_queue_send(call,
 366                                            dns_conn->conn->event.ctx,
 367                                            dns_conn->tstream,
 368                                            dns_conn->send_queue,
 369                                            call->out_iov, 2);
 370         if (subreq == NULL) {
 371                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 372                                 "no memory for tstream_writev_queue_send");
 373                 return;
 374         }
 375         tevent_req_set_callback(subreq, dns_tcp_call_writev_done, call);
 376 }
 377
 378 static void dns_tcp_call_writev_done(struct tevent_req *subreq)
 379 {
 380         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 381                         struct dns_tcp_call);
 382         int sys_errno;
 383         int rc;
 384
 385         rc = tstream_writev_queue_recv(subreq, &sys_errno);
 386         TALLOC_FREE(subreq);
 387         if (rc == -1) {
 388                 const char *reason;
 389
 390                 reason = talloc_asprintf(call, "dns_tcp_call_writev_done: "
 391                                          "tstream_writev_queue_recv() - %d:%s",
 392                                          sys_errno, strerror(sys_errno));
 393                 if (!reason) {
 394                         reason = "dns_tcp_call_writev_done: tstream_writev_queue_recv() failed";
 395                 }
 396
 397                 dns_tcp_terminate_connection(call->dns_conn, reason);
 398                 return;
 399         }
 400
 401         /* We don't care about errors */
 402
 403         talloc_free(call);
 404 }
 405
 406 /*
 407   called when we get a new connection
 408 */
 409 static void dns_tcp_accept(struct stream_connection *conn)
 410 {
 411         struct dns_socket *dns_socket;
 412         struct dns_tcp_connection *dns_conn;
 413         struct tevent_req *subreq;
 414         int rc;
 415
 416         dns_conn = talloc_zero(conn, struct dns_tcp_connection);
 417         if (dns_conn == NULL) {
 418                 stream_terminate_connection(conn,
 419                                 "dns_tcp_accept: out of memory");
 420                 return;
 421         }
 422
 423         dns_conn->send_queue = tevent_queue_create(conn, "dns_tcp_accept");
 424         if (dns_conn->send_queue == NULL) {
 425                 stream_terminate_connection(conn,
 426                                 "dns_tcp_accept: out of memory");
 427                 return;
 428         }
 429
 430         dns_socket = talloc_get_type(conn->private_data, struct dns_socket);
 431
 432         TALLOC_FREE(conn->event.fde);
 433
 434         rc = tstream_bsd_existing_socket(dns_conn,
 435                         socket_get_fd(conn->socket),
 436                         &dns_conn->tstream);
 437         if (rc < 0) {
 438                 stream_terminate_connection(conn,
 439                                 "dns_tcp_accept: out of memory");
 440                 return;
 441         }
 442
 443         dns_conn->conn = conn;
 444         dns_conn->dns_socket = dns_socket;
 445         conn->private_data = dns_conn;
 446
 447         /*
 448          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 449          * packet_full_request_u16 provides the pdu length then.
 450          */
 451         subreq = tstream_read_pdu_blob_send(dns_conn,
 452                                             dns_conn->conn->event.ctx,
 453                                             dns_conn->tstream,
 454                                             2, /* initial_read_size */
 455                                             packet_full_request_u16,
 456                                             dns_conn);
 457         if (subreq == NULL) {
 458                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_accept: "
 459                                 "no memory for tstream_read_pdu_blob_send");
 460                 return;
 461         }
 462         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 463 }
 464
 465 static const struct stream_server_ops dns_tcp_stream_ops = {
 466         .name                   = "dns_tcp",
 467         .accept_connection      = dns_tcp_accept,
 468         .recv_handler           = dns_tcp_recv,
 469         .send_handler           = dns_tcp_send
 470 };
 471
 472 struct dns_udp_call {
 473         struct dns_udp_socket *sock;
 474         struct tsocket_address *src;
 475         DATA_BLOB in;
 476         DATA_BLOB out;
 477 };
 478
 479 static void dns_udp_call_process_done(struct tevent_req *subreq);
 480 static void dns_udp_call_sendto_done(struct tevent_req *subreq);
 481
 482 static void dns_udp_call_loop(struct tevent_req *subreq)
 483 {
 484         struct dns_udp_socket *sock = tevent_req_callback_data(subreq,
 485                                       struct dns_udp_socket);
 486         struct dns_server *dns = sock->dns_socket->dns;
 487         struct dns_udp_call *call;
 488         uint8_t *buf;
 489         ssize_t len;
 490         int sys_errno;
 491
 492         call = talloc(sock, struct dns_udp_call);
 493         if (call == NULL) {
 494                 talloc_free(call);
 495                 goto done;
 496         }
 497         call->sock = sock;
 498
 499         len = tdgram_recvfrom_recv(subreq, &sys_errno,
 500                                    call, &buf, &call->src);
 501         TALLOC_FREE(subreq);
 502         if (len == -1) {
 503                 talloc_free(call);
 504                 goto done;
 505         }
 506
 507         call->in.data = buf;
 508         call->in.length = len;
 509
 510         DEBUG(10,("Received DNS UDP packet of length %lu from %s\n",
 511                  (long)call->in.length,
 512                  tsocket_address_string(call->src, call)));
 513
 514         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 515                                   &call->in);
 516         if (subreq == NULL) {
 517                 TALLOC_FREE(call);
 518                 goto done;
 519         }
 520         tevent_req_set_callback(subreq, dns_udp_call_process_done, call);
 521
 522 done:
 523         subreq = tdgram_recvfrom_send(sock,
 524                                       sock->dns_socket->dns->task->event_ctx,
 525                                       sock->dgram);
 526         if (subreq == NULL) {
 527                 task_server_terminate(sock->dns_socket->dns->task,
 528                                       "no memory for tdgram_recvfrom_send",
 529                                       true);
 530                 return;
 531         }
 532         tevent_req_set_callback(subreq, dns_udp_call_loop, sock);
 533 }
 534
 535 static void dns_udp_call_process_done(struct tevent_req *subreq)
 536 {
 537         struct dns_udp_call *call = tevent_req_callback_data(
 538                 subreq, struct dns_udp_call);
 539         struct dns_udp_socket *sock = call->sock;
 540         struct dns_server *dns = sock->dns_socket->dns;
 541         WERROR err;
 542
 543         err = dns_process_recv(subreq, call, &call->out);
 544         TALLOC_FREE(subreq);
 545         if (!W_ERROR_IS_OK(err)) {
 546                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 547                 TALLOC_FREE(call);
 548                 return;
 549         }
 550
 551         subreq = tdgram_sendto_queue_send(call,
 552                                           dns->task->event_ctx,
 553                                           sock->dgram,
 554                                           sock->send_queue,
 555                                           call->out.data,
 556                                           call->out.length,
 557                                           call->src);
 558         if (subreq == NULL) {
 559                 talloc_free(call);
 560                 return;
 561         }
 562         tevent_req_set_callback(subreq, dns_udp_call_sendto_done, call);
 563
 564 }
 565 static void dns_udp_call_sendto_done(struct tevent_req *subreq)
 566 {
 567         struct dns_udp_call *call = tevent_req_callback_data(subreq,
 568                                        struct dns_udp_call);
 569         int sys_errno;
 570
 571         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         if (ifaces != NULL) {
 672                 num_interfaces = iface_list_count(ifaces);
 673
 674                 for (i=0; i<num_interfaces; i++) {
 675                         const char *address = talloc_strdup(tmp_ctx,
 676                                                             iface_list_n_ip(ifaces, i));
 677
 678                         status = dns_add_socket(dns, model_ops, "dns", address,
 679                                                 DNS_SERVICE_PORT);
 680                         NT_STATUS_NOT_OK_RETURN(status);
 681                 }
 682         } else {
 683                 const char **wcard;
 684                 wcard = iface_list_wildcard(tmp_ctx, lp_ctx);
 685                 if (wcard == NULL) {
 686                         DEBUG(0, ("No wildcard address available\n"));
 687                         return NT_STATUS_INTERNAL_ERROR;
 688                 }
 689                 for (i = 0; wcard[i] != NULL; i++) {
 690                         status = dns_add_socket(dns, model_ops, "dns", wcard[i],
 691                                                 DNS_SERVICE_PORT);
 692                         NT_STATUS_NOT_OK_RETURN(status);
 693                 }
 694         }
 695
 696         talloc_free(tmp_ctx);
 697
 698         return NT_STATUS_OK;
 699 }
 700
 701 static int dns_server_sort_zones(struct ldb_message **m1, struct ldb_message **m2)
 702 {
 703         const char *n1, *n2;
 704         size_t l1, l2;
 705
 706         n1 = ldb_msg_find_attr_as_string(*m1, "name", NULL);
 707         n2 = ldb_msg_find_attr_as_string(*m2, "name", NULL);
 708
 709         l1 = strlen(n1);
 710         l2 = strlen(n2);
 711
 712         /* If the string lengths are not equal just sort by length */
 713         if (l1 != l2) {
 714                 /* If m1 is the larger zone name, return it first */
 715                 return l2 - l1;
 716         }
 717
 718         /*TODO: We need to compare DNs here, we want the DomainDNSZones first */
 719         return 0;
 720 }
 721
 722 static struct dns_server_tkey_store *tkey_store_init(TALLOC_CTX *mem_ctx,
 723                                                      uint16_t size)
 724 {
 725         struct dns_server_tkey_store *buffer = talloc_zero(mem_ctx,
 726                                                 struct dns_server_tkey_store);
 727
 728         if (buffer == NULL) {
 729                 return NULL;
 730         }
 731
 732         buffer->size = size;
 733         buffer->next_idx = 0;
 734
 735         buffer->tkeys = talloc_zero_array(buffer, struct dns_server_tkey *, size);
 736         if (buffer->tkeys == NULL) {
 737                 TALLOC_FREE(buffer);
 738         }
 739
 740         return buffer;
 741 }
 742
 743 static void dns_task_init(struct task_server *task)
 744 {
 745         struct dns_server *dns;
 746         NTSTATUS status;
 747         struct interface *ifaces = NULL;
 748         int ret;
 749         struct ldb_result *res;
 750         static const char * const attrs[] = { "name", NULL};
 751         static const char * const attrs_none[] = { NULL};
 752         unsigned int i;
 753         struct ldb_message *dns_acc;
 754         char *hostname_lower;
 755         char *dns_spn;
 756
 757         switch (lpcfg_server_role(task->lp_ctx)) {
 758         case ROLE_STANDALONE:
 759                 task_server_terminate(task, "dns: no DNS required in standalone configuration", false);
 760                 return;
 761         case ROLE_DOMAIN_MEMBER:
 762                 task_server_terminate(task, "dns: no DNS required in member server configuration", false);
 763                 return;
 764         case ROLE_ACTIVE_DIRECTORY_DC:
 765                 /* Yes, we want a DNS */
 766                 break;
 767         }
 768
 769         if (lpcfg_interfaces(task->lp_ctx) && lpcfg_bind_interfaces_only(task->lp_ctx)) {
 770                 load_interface_list(task, task->lp_ctx, &ifaces);
 771
 772                 if (iface_list_count(ifaces) == 0) {
 773                         task_server_terminate(task, "dns: no network interfaces configured", false);
 774                         return;
 775                 }
 776         }
 777
 778         task_server_set_title(task, "task[dns]");
 779
 780         dns = talloc_zero(task, struct dns_server);
 781         if (dns == NULL) {
 782                 task_server_terminate(task, "dns: out of memory", true);
 783                 return;
 784         }
 785
 786         dns->task = task;
 787
 788         dns->server_credentials = cli_credentials_init(dns);
 789         if (!dns->server_credentials) {
 790                 task_server_terminate(task, "Failed to init server credentials\n", true);
 791                 return;
 792         }
 793
 794         dns->samdb = samdb_connect(dns, dns->task->event_ctx, dns->task->lp_ctx,
 795                               system_session(dns->task->lp_ctx), 0);
 796         if (!dns->samdb) {
 797                 task_server_terminate(task, "dns: samdb_connect failed", true);
 798                 return;
 799         }
 800
 801         cli_credentials_set_conf(dns->server_credentials, task->lp_ctx);
 802
 803         hostname_lower = strlower_talloc(dns, lpcfg_netbios_name(task->lp_ctx));
 804         dns_spn = talloc_asprintf(dns, "DNS/%s.%s",
 805                                   hostname_lower,
 806                                   lpcfg_dnsdomain(task->lp_ctx));
 807         TALLOC_FREE(hostname_lower);
 808
 809         ret = dsdb_search_one(dns->samdb, dns, &dns_acc,
 810                               ldb_get_default_basedn(dns->samdb), LDB_SCOPE_SUBTREE,
 811                               attrs_none, 0, "(servicePrincipalName=%s)",
 812                               dns_spn);
 813         if (ret == LDB_SUCCESS) {
 814                 TALLOC_FREE(dns_acc);
 815                 if (!dns_spn) {
 816                         task_server_terminate(task, "dns: talloc_asprintf failed", true);
 817                         return;
 818                 }
 819                 status = cli_credentials_set_stored_principal(dns->server_credentials, task->lp_ctx, dns_spn);
 820                 if (!NT_STATUS_IS_OK(status)) {
 821                         task_server_terminate(task,
 822                                               talloc_asprintf(task, "Failed to obtain server credentials for DNS, "
 823                                                               "despite finding it in the samdb! %s\n",
 824                                                               nt_errstr(status)),
 825                                               true);
 826                         return;
 827                 }
 828         } else {
 829                 TALLOC_FREE(dns_spn);
 830                 status = cli_credentials_set_machine_account(dns->server_credentials, task->lp_ctx);
 831                 if (!NT_STATUS_IS_OK(status)) {
 832                         task_server_terminate(task,
 833                                               talloc_asprintf(task, "Failed to obtain server credentials, perhaps a standalone server?: %s\n",
 834                                                               nt_errstr(status)),
 835                                               true);
 836                         return;
 837                 }
 838         }
 839
 840         dns->tkeys = tkey_store_init(dns, TKEY_BUFFER_SIZE);
 841         if (!dns->tkeys) {
 842                 task_server_terminate(task, "Failed to allocate tkey storage\n", true);
 843                 return;
 844         }
 845
 846         // TODO: this search does not work against windows
 847         ret = dsdb_search(dns->samdb, dns, &res, NULL, LDB_SCOPE_SUBTREE,
 848                           attrs, DSDB_SEARCH_SEARCH_ALL_PARTITIONS, "(objectClass=dnsZone)");
 849         if (ret != LDB_SUCCESS) {
 850                 task_server_terminate(task,
 851                                       "dns: failed to look up root DNS zones",
 852                                       true);
 853                 return;
 854         }
 855
 856         TYPESAFE_QSORT(res->msgs, res->count, dns_server_sort_zones);
 857
 858         for (i=0; i < res->count; i++) {
 859                 struct dns_server_zone *z;
 860
 861                 z = talloc_zero(dns, struct dns_server_zone);
 862                 if (z == NULL) {
 863                         task_server_terminate(task, "dns failed to allocate memory", true);
 864                 }
 865
 866                 z->name = ldb_msg_find_attr_as_string(res->msgs[i], "name", NULL);
 867                 z->dn = talloc_move(z, &res->msgs[i]->dn);
 868                 /*
 869                  * Ignore the RootDNSServers zone and zones that we don't support yet
 870                  * RootDNSServers should never be returned (Windows DNS server don't)
 871                  * ..TrustAnchors should never be returned as is, (Windows returns
 872                  * TrustAnchors) and for the moment we don't support DNSSEC so we'd better
 873                  * not return this zone.
 874                  */
 875                 if ((strcmp(z->name, "RootDNSServers") == 0) ||
 876                     (strcmp(z->name, "..TrustAnchors") == 0))
 877                 {
 878                         DEBUG(10, ("Ignoring zone %s\n", z->name));
 879                         talloc_free(z);
 880                         continue;
 881                 }
 882                 DLIST_ADD_END(dns->zones, z, NULL);
 883         }
 884
 885         status = dns_startup_interfaces(dns, task->lp_ctx, ifaces);
 886         if (!NT_STATUS_IS_OK(status)) {
 887                 task_server_terminate(task, "dns failed to setup interfaces", true);
 888                 return;
 889         }
 890 }
 891
 892 NTSTATUS server_service_dns_init(void)
 893 {
 894         return register_server_service("dns", dns_task_init);
 895 }