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                 DEBUG(0, ("Signing\n"));
 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_PRINT_DEBUG(dns_name_packet, &state->out_packet);
 240
 241         ndr_err = ndr_push_struct_blob(
 242                 out, mem_ctx, &state->out_packet,
 243                 (ndr_push_flags_fn_t)ndr_push_dns_name_packet);
 244         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 245                 DEBUG(1, ("Failed to push packet: %s!\n",
 246                           ndr_errstr(ndr_err)));
 247                 state->dns_err = DNS_RCODE_SERVFAIL;
 248                 goto drop;
 249         }
 250         return WERR_OK;
 251
 252 drop:
 253         *out = data_blob_talloc(mem_ctx, state->in->data, state->in->length);
 254         if (out->data == NULL) {
 255                 return WERR_NOMEM;
 256         }
 257         out->data[2] |= 0x80; /* Toggle DNS_FLAG_REPLY */
 258         out->data[3] |= state->dns_err;
 259         return WERR_OK;
 260 }
 261
 262 struct dns_tcp_call {
 263         struct dns_tcp_connection *dns_conn;
 264         DATA_BLOB in;
 265         DATA_BLOB out;
 266         uint8_t out_hdr[4];
 267         struct iovec out_iov[2];
 268 };
 269
 270 static void dns_tcp_call_process_done(struct tevent_req *subreq);
 271 static void dns_tcp_call_writev_done(struct tevent_req *subreq);
 272
 273 static void dns_tcp_call_loop(struct tevent_req *subreq)
 274 {
 275         struct dns_tcp_connection *dns_conn = tevent_req_callback_data(subreq,
 276                                       struct dns_tcp_connection);
 277         struct dns_server *dns = dns_conn->dns_socket->dns;
 278         struct dns_tcp_call *call;
 279         NTSTATUS status;
 280
 281         call = talloc(dns_conn, struct dns_tcp_call);
 282         if (call == NULL) {
 283                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 284                                 "no memory for dns_tcp_call");
 285                 return;
 286         }
 287         call->dns_conn = dns_conn;
 288
 289         status = tstream_read_pdu_blob_recv(subreq,
 290                                             call,
 291                                             &call->in);
 292         TALLOC_FREE(subreq);
 293         if (!NT_STATUS_IS_OK(status)) {
 294                 const char *reason;
 295
 296                 reason = talloc_asprintf(call, "dns_tcp_call_loop: "
 297                                          "tstream_read_pdu_blob_recv() - %s",
 298                                          nt_errstr(status));
 299                 if (!reason) {
 300                         reason = nt_errstr(status);
 301                 }
 302
 303                 dns_tcp_terminate_connection(dns_conn, reason);
 304                 return;
 305         }
 306
 307         DEBUG(10,("Received DNS TCP packet of length %lu from %s\n",
 308                  (long) call->in.length,
 309                  tsocket_address_string(dns_conn->conn->remote_address, call)));
 310
 311         /* skip length header */
 312         call->in.data += 2;
 313         call->in.length -= 2;
 314
 315         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 316                                   &call->in);
 317         if (subreq == NULL) {
 318                 dns_tcp_terminate_connection(
 319                         dns_conn, "dns_tcp_call_loop: dns_process_send "
 320                         "failed\n");
 321                 return;
 322         }
 323         tevent_req_set_callback(subreq, dns_tcp_call_process_done, call);
 324
 325         /*
 326          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 327          * packet_full_request_u16 provides the pdu length then.
 328          */
 329         subreq = tstream_read_pdu_blob_send(dns_conn,
 330                                             dns_conn->conn->event.ctx,
 331                                             dns_conn->tstream,
 332                                             2, /* initial_read_size */
 333                                             packet_full_request_u16,
 334                                             dns_conn);
 335         if (subreq == NULL) {
 336                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 337                                 "no memory for tstream_read_pdu_blob_send");
 338                 return;
 339         }
 340         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 341 }
 342
 343 static void dns_tcp_call_process_done(struct tevent_req *subreq)
 344 {
 345         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 346                         struct dns_tcp_call);
 347         struct dns_tcp_connection *dns_conn = call->dns_conn;
 348         WERROR err;
 349
 350         err = dns_process_recv(subreq, call, &call->out);
 351         TALLOC_FREE(subreq);
 352         if (!W_ERROR_IS_OK(err)) {
 353                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 354                 dns_tcp_terminate_connection(dns_conn,
 355                                 "dns_tcp_call_loop: process function failed");
 356                 return;
 357         }
 358
 359         /* First add the length of the out buffer */
 360         RSSVAL(call->out_hdr, 0, call->out.length);
 361         call->out_iov[0].iov_base = (char *) call->out_hdr;
 362         call->out_iov[0].iov_len = 2;
 363
 364         call->out_iov[1].iov_base = (char *) call->out.data;
 365         call->out_iov[1].iov_len = call->out.length;
 366
 367         subreq = tstream_writev_queue_send(call,
 368                                            dns_conn->conn->event.ctx,
 369                                            dns_conn->tstream,
 370                                            dns_conn->send_queue,
 371                                            call->out_iov, 2);
 372         if (subreq == NULL) {
 373                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 374                                 "no memory for tstream_writev_queue_send");
 375                 return;
 376         }
 377         tevent_req_set_callback(subreq, dns_tcp_call_writev_done, call);
 378 }
 379
 380 static void dns_tcp_call_writev_done(struct tevent_req *subreq)
 381 {
 382         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 383                         struct dns_tcp_call);
 384         int sys_errno;
 385         int rc;
 386
 387         rc = tstream_writev_queue_recv(subreq, &sys_errno);
 388         TALLOC_FREE(subreq);
 389         if (rc == -1) {
 390                 const char *reason;
 391
 392                 reason = talloc_asprintf(call, "dns_tcp_call_writev_done: "
 393                                          "tstream_writev_queue_recv() - %d:%s",
 394                                          sys_errno, strerror(sys_errno));
 395                 if (!reason) {
 396                         reason = "dns_tcp_call_writev_done: tstream_writev_queue_recv() failed";
 397                 }
 398
 399                 dns_tcp_terminate_connection(call->dns_conn, reason);
 400                 return;
 401         }
 402
 403         /* We don't care about errors */
 404
 405         talloc_free(call);
 406 }
 407
 408 /*
 409   called when we get a new connection
 410 */
 411 static void dns_tcp_accept(struct stream_connection *conn)
 412 {
 413         struct dns_socket *dns_socket;
 414         struct dns_tcp_connection *dns_conn;
 415         struct tevent_req *subreq;
 416         int rc;
 417
 418         dns_conn = talloc_zero(conn, struct dns_tcp_connection);
 419         if (dns_conn == NULL) {
 420                 stream_terminate_connection(conn,
 421                                 "dns_tcp_accept: out of memory");
 422                 return;
 423         }
 424
 425         dns_conn->send_queue = tevent_queue_create(conn, "dns_tcp_accept");
 426         if (dns_conn->send_queue == NULL) {
 427                 stream_terminate_connection(conn,
 428                                 "dns_tcp_accept: out of memory");
 429                 return;
 430         }
 431
 432         dns_socket = talloc_get_type(conn->private_data, struct dns_socket);
 433
 434         TALLOC_FREE(conn->event.fde);
 435
 436         rc = tstream_bsd_existing_socket(dns_conn,
 437                         socket_get_fd(conn->socket),
 438                         &dns_conn->tstream);
 439         if (rc < 0) {
 440                 stream_terminate_connection(conn,
 441                                 "dns_tcp_accept: out of memory");
 442                 return;
 443         }
 444
 445         dns_conn->conn = conn;
 446         dns_conn->dns_socket = dns_socket;
 447         conn->private_data = dns_conn;
 448
 449         /*
 450          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 451          * packet_full_request_u16 provides the pdu length then.
 452          */
 453         subreq = tstream_read_pdu_blob_send(dns_conn,
 454                                             dns_conn->conn->event.ctx,
 455                                             dns_conn->tstream,
 456                                             2, /* initial_read_size */
 457                                             packet_full_request_u16,
 458                                             dns_conn);
 459         if (subreq == NULL) {
 460                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_accept: "
 461                                 "no memory for tstream_read_pdu_blob_send");
 462                 return;
 463         }
 464         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 465 }
 466
 467 static const struct stream_server_ops dns_tcp_stream_ops = {
 468         .name                   = "dns_tcp",
 469         .accept_connection      = dns_tcp_accept,
 470         .recv_handler           = dns_tcp_recv,
 471         .send_handler           = dns_tcp_send
 472 };
 473
 474 struct dns_udp_call {
 475         struct dns_udp_socket *sock;
 476         struct tsocket_address *src;
 477         DATA_BLOB in;
 478         DATA_BLOB out;
 479 };
 480
 481 static void dns_udp_call_process_done(struct tevent_req *subreq);
 482 static void dns_udp_call_sendto_done(struct tevent_req *subreq);
 483
 484 static void dns_udp_call_loop(struct tevent_req *subreq)
 485 {
 486         struct dns_udp_socket *sock = tevent_req_callback_data(subreq,
 487                                       struct dns_udp_socket);
 488         struct dns_server *dns = sock->dns_socket->dns;
 489         struct dns_udp_call *call;
 490         uint8_t *buf;
 491         ssize_t len;
 492         int sys_errno;
 493
 494         call = talloc(sock, struct dns_udp_call);
 495         if (call == NULL) {
 496                 talloc_free(call);
 497                 goto done;
 498         }
 499         call->sock = sock;
 500
 501         len = tdgram_recvfrom_recv(subreq, &sys_errno,
 502                                    call, &buf, &call->src);
 503         TALLOC_FREE(subreq);
 504         if (len == -1) {
 505                 talloc_free(call);
 506                 goto done;
 507         }
 508
 509         call->in.data = buf;
 510         call->in.length = len;
 511
 512         DEBUG(10,("Received DNS UDP packet of length %lu from %s\n",
 513                  (long)call->in.length,
 514                  tsocket_address_string(call->src, call)));
 515
 516         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 517                                   &call->in);
 518         if (subreq == NULL) {
 519                 TALLOC_FREE(call);
 520                 goto done;
 521         }
 522         tevent_req_set_callback(subreq, dns_udp_call_process_done, call);
 523
 524 done:
 525         subreq = tdgram_recvfrom_send(sock,
 526                                       sock->dns_socket->dns->task->event_ctx,
 527                                       sock->dgram);
 528         if (subreq == NULL) {
 529                 task_server_terminate(sock->dns_socket->dns->task,
 530                                       "no memory for tdgram_recvfrom_send",
 531                                       true);
 532                 return;
 533         }
 534         tevent_req_set_callback(subreq, dns_udp_call_loop, sock);
 535 }
 536
 537 static void dns_udp_call_process_done(struct tevent_req *subreq)
 538 {
 539         struct dns_udp_call *call = tevent_req_callback_data(
 540                 subreq, struct dns_udp_call);
 541         struct dns_udp_socket *sock = call->sock;
 542         struct dns_server *dns = sock->dns_socket->dns;
 543         WERROR err;
 544
 545         err = dns_process_recv(subreq, call, &call->out);
 546         TALLOC_FREE(subreq);
 547         if (!W_ERROR_IS_OK(err)) {
 548                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 549                 TALLOC_FREE(call);
 550                 return;
 551         }
 552
 553         subreq = tdgram_sendto_queue_send(call,
 554                                           dns->task->event_ctx,
 555                                           sock->dgram,
 556                                           sock->send_queue,
 557                                           call->out.data,
 558                                           call->out.length,
 559                                           call->src);
 560         if (subreq == NULL) {
 561                 talloc_free(call);
 562                 return;
 563         }
 564         tevent_req_set_callback(subreq, dns_udp_call_sendto_done, call);
 565
 566 }
 567 static void dns_udp_call_sendto_done(struct tevent_req *subreq)
 568 {
 569         struct dns_udp_call *call = tevent_req_callback_data(subreq,
 570                                        struct dns_udp_call);
 571         ssize_t ret;
 572         int sys_errno;
 573
 574         ret = tdgram_sendto_queue_recv(subreq, &sys_errno);
 575
 576         /* We don't care about errors */
 577
 578         talloc_free(call);
 579 }
 580
 581 /*
 582   start listening on the given address
 583 */
 584 static NTSTATUS dns_add_socket(struct dns_server *dns,
 585                                const struct model_ops *model_ops,
 586                                const char *name,
 587                                const char *address,
 588                                uint16_t port)
 589 {
 590         struct dns_socket *dns_socket;
 591         struct dns_udp_socket *dns_udp_socket;
 592         struct tevent_req *udpsubreq;
 593         NTSTATUS status;
 594         int ret;
 595
 596         dns_socket = talloc(dns, struct dns_socket);
 597         NT_STATUS_HAVE_NO_MEMORY(dns_socket);
 598
 599         dns_socket->dns = dns;
 600
 601         ret = tsocket_address_inet_from_strings(dns_socket, "ip",
 602                                                 address, port,
 603                                                 &dns_socket->local_address);
 604         if (ret != 0) {
 605                 status = map_nt_error_from_unix_common(errno);
 606                 return status;
 607         }
 608
 609         status = stream_setup_socket(dns->task,
 610                                      dns->task->event_ctx,
 611                                      dns->task->lp_ctx,
 612                                      model_ops,
 613                                      &dns_tcp_stream_ops,
 614                                      "ip", address, &port,
 615                                      lpcfg_socket_options(dns->task->lp_ctx),
 616                                      dns_socket);
 617         if (!NT_STATUS_IS_OK(status)) {
 618                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 619                          address, port, nt_errstr(status)));
 620                 talloc_free(dns_socket);
 621                 return status;
 622         }
 623
 624         dns_udp_socket = talloc(dns_socket, struct dns_udp_socket);
 625         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket);
 626
 627         dns_udp_socket->dns_socket = dns_socket;
 628
 629         ret = tdgram_inet_udp_socket(dns_socket->local_address,
 630                                      NULL,
 631                                      dns_udp_socket,
 632                                      &dns_udp_socket->dgram);
 633         if (ret != 0) {
 634                 status = map_nt_error_from_unix_common(errno);
 635                 DEBUG(0,("Failed to bind to %s:%u UDP - %s\n",
 636                          address, port, nt_errstr(status)));
 637                 return status;
 638         }
 639
 640         dns_udp_socket->send_queue = tevent_queue_create(dns_udp_socket,
 641                                                          "dns_udp_send_queue");
 642         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket->send_queue);
 643
 644         udpsubreq = tdgram_recvfrom_send(dns_udp_socket,
 645                                          dns->task->event_ctx,
 646                                          dns_udp_socket->dgram);
 647         NT_STATUS_HAVE_NO_MEMORY(udpsubreq);
 648         tevent_req_set_callback(udpsubreq, dns_udp_call_loop, dns_udp_socket);
 649
 650         return NT_STATUS_OK;
 651 }
 652
 653 /*
 654   setup our listening sockets on the configured network interfaces
 655 */
 656 static NTSTATUS dns_startup_interfaces(struct dns_server *dns, struct loadparm_context *lp_ctx,
 657                                        struct interface *ifaces)
 658 {
 659         const struct model_ops *model_ops;
 660         int num_interfaces;
 661         TALLOC_CTX *tmp_ctx = talloc_new(dns);
 662         NTSTATUS status;
 663         int i;
 664
 665         /* within the dns task we want to be a single process, so
 666            ask for the single process model ops and pass these to the
 667            stream_setup_socket() call. */
 668         model_ops = process_model_startup("single");
 669         if (!model_ops) {
 670                 DEBUG(0,("Can't find 'single' process model_ops\n"));
 671                 return NT_STATUS_INTERNAL_ERROR;
 672         }
 673
 674         num_interfaces = iface_list_count(ifaces);
 675
 676         for (i=0; i<num_interfaces; i++) {
 677                 const char *address = talloc_strdup(tmp_ctx, iface_list_n_ip(ifaces, i));
 678
 679                 status = dns_add_socket(dns, model_ops, "dns", address, DNS_SERVICE_PORT);
 680                 NT_STATUS_NOT_OK_RETURN(status);
 681         }
 682
 683         talloc_free(tmp_ctx);
 684
 685         return NT_STATUS_OK;
 686 }
 687
 688 static int dns_server_sort_zones(struct ldb_message **m1, struct ldb_message **m2)
 689 {
 690         const char *n1, *n2;
 691         size_t l1, l2;
 692
 693         n1 = ldb_msg_find_attr_as_string(*m1, "name", NULL);
 694         n2 = ldb_msg_find_attr_as_string(*m2, "name", NULL);
 695
 696         l1 = strlen(n1);
 697         l2 = strlen(n2);
 698
 699         /* If the string lengths are not equal just sort by length */
 700         if (l1 != l2) {
 701                 /* If m1 is the larger zone name, return it first */
 702                 return l2 - l1;
 703         }
 704
 705         /*TODO: We need to compare DNs here, we want the DomainDNSZones first */
 706         return 0;
 707 }
 708
 709 static struct dns_server_tkey_store *tkey_store_init(TALLOC_CTX *mem_ctx,
 710                                                      uint16_t size)
 711 {
 712         struct dns_server_tkey_store *buffer = talloc_zero(mem_ctx,
 713                                                 struct dns_server_tkey_store);
 714
 715         if (buffer == NULL) {
 716                 return NULL;
 717         }
 718
 719         buffer->size = size;
 720         buffer->next_idx = 0;
 721
 722         buffer->tkeys = talloc_zero_array(buffer, struct dns_server_tkey *, size);
 723         if (buffer->tkeys == NULL) {
 724                 TALLOC_FREE(buffer);
 725         }
 726
 727         return buffer;
 728 }
 729
 730 static void dns_task_init(struct task_server *task)
 731 {
 732         struct dns_server *dns;
 733         NTSTATUS status;
 734         struct interface *ifaces;
 735         int ret;
 736         struct ldb_result *res;
 737         static const char * const attrs[] = { "name", NULL};
 738         unsigned int i;
 739
 740         switch (lpcfg_server_role(task->lp_ctx)) {
 741         case ROLE_STANDALONE:
 742                 task_server_terminate(task, "dns: no DNS required in standalone configuration", false);
 743                 return;
 744         case ROLE_DOMAIN_MEMBER:
 745                 task_server_terminate(task, "dns: no DNS required in member server configuration", false);
 746                 return;
 747         case ROLE_ACTIVE_DIRECTORY_DC:
 748                 /* Yes, we want a DNS */
 749                 break;
 750         }
 751
 752         load_interface_list(task, task->lp_ctx, &ifaces);
 753
 754         if (iface_list_count(ifaces) == 0) {
 755                 task_server_terminate(task, "dns: no network interfaces configured", false);
 756                 return;
 757         }
 758
 759         task_server_set_title(task, "task[dns]");
 760
 761         dns = talloc_zero(task, struct dns_server);
 762         if (dns == NULL) {
 763                 task_server_terminate(task, "dns: out of memory", true);
 764                 return;
 765         }
 766
 767         dns->task = task;
 768
 769         dns->server_credentials = cli_credentials_init(dns);
 770         if (!dns->server_credentials) {
 771                 task_server_terminate(task, "Failed to init server credentials\n", true);
 772                 return;
 773         }
 774
 775         cli_credentials_set_conf(dns->server_credentials, task->lp_ctx);
 776         status = cli_credentials_set_machine_account(dns->server_credentials, task->lp_ctx);
 777         if (!NT_STATUS_IS_OK(status)) {
 778                 task_server_terminate(task,
 779                         talloc_asprintf(task, "Failed to obtain server credentials, perhaps a standalone server?: %s\n",
 780                                         nt_errstr(status)),
 781                         true);
 782                 return;
 783         }
 784
 785         dns->tkeys = tkey_store_init(dns, TKEY_BUFFER_SIZE);
 786         if (!dns->tkeys) {
 787                 task_server_terminate(task, "Failed to allocate tkey storage\n", true);
 788                 return;
 789         }
 790
 791         dns->samdb = samdb_connect(dns, dns->task->event_ctx, dns->task->lp_ctx,
 792                               system_session(dns->task->lp_ctx), 0);
 793         if (!dns->samdb) {
 794                 task_server_terminate(task, "dns: samdb_connect failed", true);
 795                 return;
 796         }
 797
 798         // TODO: this search does not work against windows
 799         ret = dsdb_search(dns->samdb, dns, &res, NULL, LDB_SCOPE_SUBTREE,
 800                           attrs, DSDB_SEARCH_SEARCH_ALL_PARTITIONS, "(objectClass=dnsZone)");
 801         if (ret != LDB_SUCCESS) {
 802                 task_server_terminate(task,
 803                                       "dns: failed to look up root DNS zones",
 804                                       true);
 805                 return;
 806         }
 807
 808         TYPESAFE_QSORT(res->msgs, res->count, dns_server_sort_zones);
 809
 810         for (i=0; i < res->count; i++) {
 811                 struct dns_server_zone *z;
 812
 813                 z = talloc_zero(dns, struct dns_server_zone);
 814                 if (z == NULL) {
 815                 }
 816
 817                 z->name = ldb_msg_find_attr_as_string(res->msgs[i], "name", NULL);
 818                 z->dn = talloc_move(z, &res->msgs[i]->dn);
 819
 820                 DLIST_ADD_END(dns->zones, z, NULL);
 821         }
 822
 823         status = dns_startup_interfaces(dns, task->lp_ctx, ifaces);
 824         if (!NT_STATUS_IS_OK(status)) {
 825                 task_server_terminate(task, "dns failed to setup interfaces", true);
 826                 return;
 827         }
 828 }
 829
 830 NTSTATUS server_service_dns_init(void)
 831 {
 832         return register_server_service("dns", dns_task_init);
 833 }