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         if (state->in_packet.operation & DNS_FLAG_REPLY) {
 157                 DEBUG(1, ("Won't reply to replies.\n"));
 158                 tevent_req_werror(req, WERR_INVALID_PARAM);
 159                 return tevent_req_post(req, ev);
 160         }
 161
 162         state->state.flags = state->in_packet.operation;
 163         state->state.flags |= DNS_FLAG_REPLY;
 164
 165
 166         if (forwarder && *forwarder) {
 167                 state->state.flags |= DNS_FLAG_RECURSION_AVAIL;
 168         }
 169
 170         state->out_packet = state->in_packet;
 171
 172         switch (state->in_packet.operation & DNS_OPCODE) {
 173         case DNS_OPCODE_QUERY:
 174                 subreq = dns_server_process_query_send(
 175                         state, ev, dns, &state->state, &state->in_packet);
 176                 if (tevent_req_nomem(subreq, req)) {
 177                         return tevent_req_post(req, ev);
 178                 }
 179                 tevent_req_set_callback(subreq, dns_process_done, req);
 180                 return req;
 181         case DNS_OPCODE_UPDATE:
 182                 ret = dns_server_process_update(
 183                         dns, &state->state, state, &state->in_packet,
 184                         &state->out_packet.answers, &state->out_packet.ancount,
 185                         &state->out_packet.nsrecs,  &state->out_packet.nscount,
 186                         &state->out_packet.additional,
 187                         &state->out_packet.arcount);
 188                 break;
 189         default:
 190                 ret = WERR_DNS_ERROR_RCODE_NOT_IMPLEMENTED;
 191         }
 192         if (!W_ERROR_IS_OK(ret)) {
 193                 state->dns_err = werr_to_dns_err(ret);
 194         }
 195         tevent_req_done(req);
 196         return tevent_req_post(req, ev);
 197 }
 198
 199 static void dns_process_done(struct tevent_req *subreq)
 200 {
 201         struct tevent_req *req = tevent_req_callback_data(
 202                 subreq, struct tevent_req);
 203         struct dns_process_state *state = tevent_req_data(
 204                 req, struct dns_process_state);
 205         WERROR ret;
 206
 207         ret = dns_server_process_query_recv(
 208                 subreq, state,
 209                 &state->out_packet.answers, &state->out_packet.ancount,
 210                 &state->out_packet.nsrecs,  &state->out_packet.nscount,
 211                 &state->out_packet.additional, &state->out_packet.arcount);
 212         TALLOC_FREE(subreq);
 213
 214         if (!W_ERROR_IS_OK(ret)) {
 215                 state->dns_err = werr_to_dns_err(ret);
 216         }
 217         tevent_req_done(req);
 218 }
 219
 220 static WERROR dns_process_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 221                                DATA_BLOB *out)
 222 {
 223         struct dns_process_state *state = tevent_req_data(
 224                 req, struct dns_process_state);
 225         enum ndr_err_code ndr_err;
 226         WERROR ret;
 227
 228         if (tevent_req_is_werror(req, &ret)) {
 229                 return ret;
 230         }
 231         if (state->dns_err != DNS_RCODE_OK) {
 232                 goto drop;
 233         }
 234         state->out_packet.operation |= state->state.flags;
 235
 236         if (state->state.sign) {
 237                 ret = dns_sign_tsig(state->dns, mem_ctx, &state->state,
 238                                     &state->out_packet, 0);
 239                 if (!W_ERROR_IS_OK(ret)) {
 240                         state->dns_err = DNS_RCODE_SERVFAIL;
 241                         goto drop;
 242                 }
 243         }
 244
 245         ndr_err = ndr_push_struct_blob(
 246                 out, mem_ctx, &state->out_packet,
 247                 (ndr_push_flags_fn_t)ndr_push_dns_name_packet);
 248         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 249                 DEBUG(1, ("Failed to push packet: %s!\n",
 250                           ndr_errstr(ndr_err)));
 251                 state->dns_err = DNS_RCODE_SERVFAIL;
 252                 goto drop;
 253         }
 254         return WERR_OK;
 255
 256 drop:
 257         *out = data_blob_talloc(mem_ctx, state->in->data, state->in->length);
 258         if (out->data == NULL) {
 259                 return WERR_NOMEM;
 260         }
 261         out->data[2] |= 0x80; /* Toggle DNS_FLAG_REPLY */
 262         out->data[3] |= state->dns_err;
 263         return WERR_OK;
 264 }
 265
 266 struct dns_tcp_call {
 267         struct dns_tcp_connection *dns_conn;
 268         DATA_BLOB in;
 269         DATA_BLOB out;
 270         uint8_t out_hdr[4];
 271         struct iovec out_iov[2];
 272 };
 273
 274 static void dns_tcp_call_process_done(struct tevent_req *subreq);
 275 static void dns_tcp_call_writev_done(struct tevent_req *subreq);
 276
 277 static void dns_tcp_call_loop(struct tevent_req *subreq)
 278 {
 279         struct dns_tcp_connection *dns_conn = tevent_req_callback_data(subreq,
 280                                       struct dns_tcp_connection);
 281         struct dns_server *dns = dns_conn->dns_socket->dns;
 282         struct dns_tcp_call *call;
 283         NTSTATUS status;
 284
 285         call = talloc(dns_conn, struct dns_tcp_call);
 286         if (call == NULL) {
 287                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 288                                 "no memory for dns_tcp_call");
 289                 return;
 290         }
 291         call->dns_conn = dns_conn;
 292
 293         status = tstream_read_pdu_blob_recv(subreq,
 294                                             call,
 295                                             &call->in);
 296         TALLOC_FREE(subreq);
 297         if (!NT_STATUS_IS_OK(status)) {
 298                 const char *reason;
 299
 300                 reason = talloc_asprintf(call, "dns_tcp_call_loop: "
 301                                          "tstream_read_pdu_blob_recv() - %s",
 302                                          nt_errstr(status));
 303                 if (!reason) {
 304                         reason = nt_errstr(status);
 305                 }
 306
 307                 dns_tcp_terminate_connection(dns_conn, reason);
 308                 return;
 309         }
 310
 311         DEBUG(10,("Received DNS TCP packet of length %lu from %s\n",
 312                  (long) call->in.length,
 313                  tsocket_address_string(dns_conn->conn->remote_address, call)));
 314
 315         /* skip length header */
 316         call->in.data += 2;
 317         call->in.length -= 2;
 318
 319         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 320                                   &call->in);
 321         if (subreq == NULL) {
 322                 dns_tcp_terminate_connection(
 323                         dns_conn, "dns_tcp_call_loop: dns_process_send "
 324                         "failed\n");
 325                 return;
 326         }
 327         tevent_req_set_callback(subreq, dns_tcp_call_process_done, call);
 328
 329         /*
 330          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 331          * packet_full_request_u16 provides the pdu length then.
 332          */
 333         subreq = tstream_read_pdu_blob_send(dns_conn,
 334                                             dns_conn->conn->event.ctx,
 335                                             dns_conn->tstream,
 336                                             2, /* initial_read_size */
 337                                             packet_full_request_u16,
 338                                             dns_conn);
 339         if (subreq == NULL) {
 340                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 341                                 "no memory for tstream_read_pdu_blob_send");
 342                 return;
 343         }
 344         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 345 }
 346
 347 static void dns_tcp_call_process_done(struct tevent_req *subreq)
 348 {
 349         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 350                         struct dns_tcp_call);
 351         struct dns_tcp_connection *dns_conn = call->dns_conn;
 352         WERROR err;
 353
 354         err = dns_process_recv(subreq, call, &call->out);
 355         TALLOC_FREE(subreq);
 356         if (!W_ERROR_IS_OK(err)) {
 357                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 358                 dns_tcp_terminate_connection(dns_conn,
 359                                 "dns_tcp_call_loop: process function failed");
 360                 return;
 361         }
 362
 363         /* First add the length of the out buffer */
 364         RSSVAL(call->out_hdr, 0, call->out.length);
 365         call->out_iov[0].iov_base = (char *) call->out_hdr;
 366         call->out_iov[0].iov_len = 2;
 367
 368         call->out_iov[1].iov_base = (char *) call->out.data;
 369         call->out_iov[1].iov_len = call->out.length;
 370
 371         subreq = tstream_writev_queue_send(call,
 372                                            dns_conn->conn->event.ctx,
 373                                            dns_conn->tstream,
 374                                            dns_conn->send_queue,
 375                                            call->out_iov, 2);
 376         if (subreq == NULL) {
 377                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 378                                 "no memory for tstream_writev_queue_send");
 379                 return;
 380         }
 381         tevent_req_set_callback(subreq, dns_tcp_call_writev_done, call);
 382 }
 383
 384 static void dns_tcp_call_writev_done(struct tevent_req *subreq)
 385 {
 386         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 387                         struct dns_tcp_call);
 388         int sys_errno;
 389         int rc;
 390
 391         rc = tstream_writev_queue_recv(subreq, &sys_errno);
 392         TALLOC_FREE(subreq);
 393         if (rc == -1) {
 394                 const char *reason;
 395
 396                 reason = talloc_asprintf(call, "dns_tcp_call_writev_done: "
 397                                          "tstream_writev_queue_recv() - %d:%s",
 398                                          sys_errno, strerror(sys_errno));
 399                 if (!reason) {
 400                         reason = "dns_tcp_call_writev_done: tstream_writev_queue_recv() failed";
 401                 }
 402
 403                 dns_tcp_terminate_connection(call->dns_conn, reason);
 404                 return;
 405         }
 406
 407         /* We don't care about errors */
 408
 409         talloc_free(call);
 410 }
 411
 412 /*
 413   called when we get a new connection
 414 */
 415 static void dns_tcp_accept(struct stream_connection *conn)
 416 {
 417         struct dns_socket *dns_socket;
 418         struct dns_tcp_connection *dns_conn;
 419         struct tevent_req *subreq;
 420         int rc;
 421
 422         dns_conn = talloc_zero(conn, struct dns_tcp_connection);
 423         if (dns_conn == NULL) {
 424                 stream_terminate_connection(conn,
 425                                 "dns_tcp_accept: out of memory");
 426                 return;
 427         }
 428
 429         dns_conn->send_queue = tevent_queue_create(conn, "dns_tcp_accept");
 430         if (dns_conn->send_queue == NULL) {
 431                 stream_terminate_connection(conn,
 432                                 "dns_tcp_accept: out of memory");
 433                 return;
 434         }
 435
 436         dns_socket = talloc_get_type(conn->private_data, struct dns_socket);
 437
 438         TALLOC_FREE(conn->event.fde);
 439
 440         rc = tstream_bsd_existing_socket(dns_conn,
 441                         socket_get_fd(conn->socket),
 442                         &dns_conn->tstream);
 443         if (rc < 0) {
 444                 stream_terminate_connection(conn,
 445                                 "dns_tcp_accept: out of memory");
 446                 return;
 447         }
 448
 449         dns_conn->conn = conn;
 450         dns_conn->dns_socket = dns_socket;
 451         conn->private_data = dns_conn;
 452
 453         /*
 454          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 455          * packet_full_request_u16 provides the pdu length then.
 456          */
 457         subreq = tstream_read_pdu_blob_send(dns_conn,
 458                                             dns_conn->conn->event.ctx,
 459                                             dns_conn->tstream,
 460                                             2, /* initial_read_size */
 461                                             packet_full_request_u16,
 462                                             dns_conn);
 463         if (subreq == NULL) {
 464                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_accept: "
 465                                 "no memory for tstream_read_pdu_blob_send");
 466                 return;
 467         }
 468         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 469 }
 470
 471 static const struct stream_server_ops dns_tcp_stream_ops = {
 472         .name                   = "dns_tcp",
 473         .accept_connection      = dns_tcp_accept,
 474         .recv_handler           = dns_tcp_recv,
 475         .send_handler           = dns_tcp_send
 476 };
 477
 478 struct dns_udp_call {
 479         struct dns_udp_socket *sock;
 480         struct tsocket_address *src;
 481         DATA_BLOB in;
 482         DATA_BLOB out;
 483 };
 484
 485 static void dns_udp_call_process_done(struct tevent_req *subreq);
 486 static void dns_udp_call_sendto_done(struct tevent_req *subreq);
 487
 488 static void dns_udp_call_loop(struct tevent_req *subreq)
 489 {
 490         struct dns_udp_socket *sock = tevent_req_callback_data(subreq,
 491                                       struct dns_udp_socket);
 492         struct dns_server *dns = sock->dns_socket->dns;
 493         struct dns_udp_call *call;
 494         uint8_t *buf;
 495         ssize_t len;
 496         int sys_errno;
 497
 498         call = talloc(sock, struct dns_udp_call);
 499         if (call == NULL) {
 500                 talloc_free(call);
 501                 goto done;
 502         }
 503         call->sock = sock;
 504
 505         len = tdgram_recvfrom_recv(subreq, &sys_errno,
 506                                    call, &buf, &call->src);
 507         TALLOC_FREE(subreq);
 508         if (len == -1) {
 509                 talloc_free(call);
 510                 goto done;
 511         }
 512
 513         call->in.data = buf;
 514         call->in.length = len;
 515
 516         DEBUG(10,("Received DNS UDP packet of length %lu from %s\n",
 517                  (long)call->in.length,
 518                  tsocket_address_string(call->src, call)));
 519
 520         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 521                                   &call->in);
 522         if (subreq == NULL) {
 523                 TALLOC_FREE(call);
 524                 goto done;
 525         }
 526         tevent_req_set_callback(subreq, dns_udp_call_process_done, call);
 527
 528 done:
 529         subreq = tdgram_recvfrom_send(sock,
 530                                       sock->dns_socket->dns->task->event_ctx,
 531                                       sock->dgram);
 532         if (subreq == NULL) {
 533                 task_server_terminate(sock->dns_socket->dns->task,
 534                                       "no memory for tdgram_recvfrom_send",
 535                                       true);
 536                 return;
 537         }
 538         tevent_req_set_callback(subreq, dns_udp_call_loop, sock);
 539 }
 540
 541 static void dns_udp_call_process_done(struct tevent_req *subreq)
 542 {
 543         struct dns_udp_call *call = tevent_req_callback_data(
 544                 subreq, struct dns_udp_call);
 545         struct dns_udp_socket *sock = call->sock;
 546         struct dns_server *dns = sock->dns_socket->dns;
 547         WERROR err;
 548
 549         err = dns_process_recv(subreq, call, &call->out);
 550         TALLOC_FREE(subreq);
 551         if (!W_ERROR_IS_OK(err)) {
 552                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 553                 TALLOC_FREE(call);
 554                 return;
 555         }
 556
 557         subreq = tdgram_sendto_queue_send(call,
 558                                           dns->task->event_ctx,
 559                                           sock->dgram,
 560                                           sock->send_queue,
 561                                           call->out.data,
 562                                           call->out.length,
 563                                           call->src);
 564         if (subreq == NULL) {
 565                 talloc_free(call);
 566                 return;
 567         }
 568         tevent_req_set_callback(subreq, dns_udp_call_sendto_done, call);
 569
 570 }
 571 static void dns_udp_call_sendto_done(struct tevent_req *subreq)
 572 {
 573         struct dns_udp_call *call = tevent_req_callback_data(subreq,
 574                                        struct dns_udp_call);
 575         int sys_errno;
 576
 577         tdgram_sendto_queue_recv(subreq, &sys_errno);
 578
 579         /* We don't care about errors */
 580
 581         talloc_free(call);
 582 }
 583
 584 /*
 585   start listening on the given address
 586 */
 587 static NTSTATUS dns_add_socket(struct dns_server *dns,
 588                                const struct model_ops *model_ops,
 589                                const char *name,
 590                                const char *address,
 591                                uint16_t port)
 592 {
 593         struct dns_socket *dns_socket;
 594         struct dns_udp_socket *dns_udp_socket;
 595         struct tevent_req *udpsubreq;
 596         NTSTATUS status;
 597         int ret;
 598
 599         dns_socket = talloc(dns, struct dns_socket);
 600         NT_STATUS_HAVE_NO_MEMORY(dns_socket);
 601
 602         dns_socket->dns = dns;
 603
 604         ret = tsocket_address_inet_from_strings(dns_socket, "ip",
 605                                                 address, port,
 606                                                 &dns_socket->local_address);
 607         if (ret != 0) {
 608                 status = map_nt_error_from_unix_common(errno);
 609                 return status;
 610         }
 611
 612         status = stream_setup_socket(dns->task,
 613                                      dns->task->event_ctx,
 614                                      dns->task->lp_ctx,
 615                                      model_ops,
 616                                      &dns_tcp_stream_ops,
 617                                      "ip", address, &port,
 618                                      lpcfg_socket_options(dns->task->lp_ctx),
 619                                      dns_socket);
 620         if (!NT_STATUS_IS_OK(status)) {
 621                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 622                          address, port, nt_errstr(status)));
 623                 talloc_free(dns_socket);
 624                 return status;
 625         }
 626
 627         dns_udp_socket = talloc(dns_socket, struct dns_udp_socket);
 628         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket);
 629
 630         dns_udp_socket->dns_socket = dns_socket;
 631
 632         ret = tdgram_inet_udp_socket(dns_socket->local_address,
 633                                      NULL,
 634                                      dns_udp_socket,
 635                                      &dns_udp_socket->dgram);
 636         if (ret != 0) {
 637                 status = map_nt_error_from_unix_common(errno);
 638                 DEBUG(0,("Failed to bind to %s:%u UDP - %s\n",
 639                          address, port, nt_errstr(status)));
 640                 return status;
 641         }
 642
 643         dns_udp_socket->send_queue = tevent_queue_create(dns_udp_socket,
 644                                                          "dns_udp_send_queue");
 645         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket->send_queue);
 646
 647         udpsubreq = tdgram_recvfrom_send(dns_udp_socket,
 648                                          dns->task->event_ctx,
 649                                          dns_udp_socket->dgram);
 650         NT_STATUS_HAVE_NO_MEMORY(udpsubreq);
 651         tevent_req_set_callback(udpsubreq, dns_udp_call_loop, dns_udp_socket);
 652
 653         return NT_STATUS_OK;
 654 }
 655
 656 /*
 657   setup our listening sockets on the configured network interfaces
 658 */
 659 static NTSTATUS dns_startup_interfaces(struct dns_server *dns,
 660                                        struct interface *ifaces)
 661 {
 662         const struct model_ops *model_ops;
 663         int num_interfaces;
 664         TALLOC_CTX *tmp_ctx = talloc_new(dns);
 665         NTSTATUS status;
 666         int i;
 667
 668         /* within the dns task we want to be a single process, so
 669            ask for the single process model ops and pass these to the
 670            stream_setup_socket() call. */
 671         model_ops = process_model_startup("single");
 672         if (!model_ops) {
 673                 DEBUG(0,("Can't find 'single' process model_ops\n"));
 674                 return NT_STATUS_INTERNAL_ERROR;
 675         }
 676
 677         if (ifaces != NULL) {
 678                 num_interfaces = iface_list_count(ifaces);
 679
 680                 for (i=0; i<num_interfaces; i++) {
 681                         const char *address = talloc_strdup(tmp_ctx,
 682                                                             iface_list_n_ip(ifaces, i));
 683
 684                         status = dns_add_socket(dns, model_ops, "dns", address,
 685                                                 DNS_SERVICE_PORT);
 686                         NT_STATUS_NOT_OK_RETURN(status);
 687                 }
 688         } else {
 689                 int num_binds = 0;
 690                 char **wcard;
 691                 wcard = iface_list_wildcard(tmp_ctx);
 692                 if (wcard == NULL) {
 693                         DEBUG(0, ("No wildcard address available\n"));
 694                         return NT_STATUS_INTERNAL_ERROR;
 695                 }
 696                 for (i = 0; wcard[i] != NULL; i++) {
 697                         status = dns_add_socket(dns, model_ops, "dns", wcard[i],
 698                                                 DNS_SERVICE_PORT);
 699                         if (NT_STATUS_IS_OK(status)) {
 700                                 num_binds++;
 701                         }
 702                 }
 703                 if (num_binds == 0) {
 704                         talloc_free(tmp_ctx);
 705                         return NT_STATUS_INVALID_PARAMETER_MIX;
 706                 }
 707         }
 708
 709         talloc_free(tmp_ctx);
 710
 711         return NT_STATUS_OK;
 712 }
 713
 714 static int dns_server_sort_zones(struct ldb_message **m1, struct ldb_message **m2)
 715 {
 716         const char *n1, *n2;
 717         size_t l1, l2;
 718
 719         n1 = ldb_msg_find_attr_as_string(*m1, "name", NULL);
 720         n2 = ldb_msg_find_attr_as_string(*m2, "name", NULL);
 721
 722         l1 = strlen(n1);
 723         l2 = strlen(n2);
 724
 725         /* If the string lengths are not equal just sort by length */
 726         if (l1 != l2) {
 727                 /* If m1 is the larger zone name, return it first */
 728                 return l2 - l1;
 729         }
 730
 731         /*TODO: We need to compare DNs here, we want the DomainDNSZones first */
 732         return 0;
 733 }
 734
 735 static struct dns_server_tkey_store *tkey_store_init(TALLOC_CTX *mem_ctx,
 736                                                      uint16_t size)
 737 {
 738         struct dns_server_tkey_store *buffer = talloc_zero(mem_ctx,
 739                                                 struct dns_server_tkey_store);
 740
 741         if (buffer == NULL) {
 742                 return NULL;
 743         }
 744
 745         buffer->size = size;
 746         buffer->next_idx = 0;
 747
 748         buffer->tkeys = talloc_zero_array(buffer, struct dns_server_tkey *, size);
 749         if (buffer->tkeys == NULL) {
 750                 TALLOC_FREE(buffer);
 751         }
 752
 753         return buffer;
 754 }
 755
 756 static void dns_task_init(struct task_server *task)
 757 {
 758         struct dns_server *dns;
 759         NTSTATUS status;
 760         struct interface *ifaces = NULL;
 761         int ret;
 762         struct ldb_result *res;
 763         static const char * const attrs[] = { "name", NULL};
 764         static const char * const attrs_none[] = { NULL};
 765         unsigned int i;
 766         struct ldb_message *dns_acc;
 767         char *hostname_lower;
 768         char *dns_spn;
 769
 770         switch (lpcfg_server_role(task->lp_ctx)) {
 771         case ROLE_STANDALONE:
 772                 task_server_terminate(task, "dns: no DNS required in standalone configuration", false);
 773                 return;
 774         case ROLE_DOMAIN_MEMBER:
 775                 task_server_terminate(task, "dns: no DNS required in member server configuration", false);
 776                 return;
 777         case ROLE_ACTIVE_DIRECTORY_DC:
 778                 /* Yes, we want a DNS */
 779                 break;
 780         }
 781
 782         if (lpcfg_interfaces(task->lp_ctx) && lpcfg_bind_interfaces_only(task->lp_ctx)) {
 783                 load_interface_list(task, task->lp_ctx, &ifaces);
 784
 785                 if (iface_list_count(ifaces) == 0) {
 786                         task_server_terminate(task, "dns: no network interfaces configured", false);
 787                         return;
 788                 }
 789         }
 790
 791         task_server_set_title(task, "task[dns]");
 792
 793         dns = talloc_zero(task, struct dns_server);
 794         if (dns == NULL) {
 795                 task_server_terminate(task, "dns: out of memory", true);
 796                 return;
 797         }
 798
 799         dns->task = task;
 800         /*FIXME: Make this a configurable option */
 801         dns->max_payload = 4096;
 802
 803         dns->server_credentials = cli_credentials_init(dns);
 804         if (!dns->server_credentials) {
 805                 task_server_terminate(task, "Failed to init server credentials\n", true);
 806                 return;
 807         }
 808
 809         dns->samdb = samdb_connect(dns, dns->task->event_ctx, dns->task->lp_ctx,
 810                               system_session(dns->task->lp_ctx), 0);
 811         if (!dns->samdb) {
 812                 task_server_terminate(task, "dns: samdb_connect failed", true);
 813                 return;
 814         }
 815
 816         cli_credentials_set_conf(dns->server_credentials, task->lp_ctx);
 817
 818         hostname_lower = strlower_talloc(dns, lpcfg_netbios_name(task->lp_ctx));
 819         dns_spn = talloc_asprintf(dns, "DNS/%s.%s",
 820                                   hostname_lower,
 821                                   lpcfg_dnsdomain(task->lp_ctx));
 822         TALLOC_FREE(hostname_lower);
 823
 824         ret = dsdb_search_one(dns->samdb, dns, &dns_acc,
 825                               ldb_get_default_basedn(dns->samdb), LDB_SCOPE_SUBTREE,
 826                               attrs_none, 0, "(servicePrincipalName=%s)",
 827                               dns_spn);
 828         if (ret == LDB_SUCCESS) {
 829                 TALLOC_FREE(dns_acc);
 830                 if (!dns_spn) {
 831                         task_server_terminate(task, "dns: talloc_asprintf failed", true);
 832                         return;
 833                 }
 834                 status = cli_credentials_set_stored_principal(dns->server_credentials, task->lp_ctx, dns_spn);
 835                 if (!NT_STATUS_IS_OK(status)) {
 836                         task_server_terminate(task,
 837                                               talloc_asprintf(task, "Failed to obtain server credentials for DNS, "
 838                                                               "despite finding it in the samdb! %s\n",
 839                                                               nt_errstr(status)),
 840                                               true);
 841                         return;
 842                 }
 843         } else {
 844                 TALLOC_FREE(dns_spn);
 845                 status = cli_credentials_set_machine_account(dns->server_credentials, task->lp_ctx);
 846                 if (!NT_STATUS_IS_OK(status)) {
 847                         task_server_terminate(task,
 848                                               talloc_asprintf(task, "Failed to obtain server credentials, perhaps a standalone server?: %s\n",
 849                                                               nt_errstr(status)),
 850                                               true);
 851                         return;
 852                 }
 853         }
 854
 855         dns->tkeys = tkey_store_init(dns, TKEY_BUFFER_SIZE);
 856         if (!dns->tkeys) {
 857                 task_server_terminate(task, "Failed to allocate tkey storage\n", true);
 858                 return;
 859         }
 860
 861         // TODO: this search does not work against windows
 862         ret = dsdb_search(dns->samdb, dns, &res, NULL, LDB_SCOPE_SUBTREE,
 863                           attrs, DSDB_SEARCH_SEARCH_ALL_PARTITIONS, "(objectClass=dnsZone)");
 864         if (ret != LDB_SUCCESS) {
 865                 task_server_terminate(task,
 866                                       "dns: failed to look up root DNS zones",
 867                                       true);
 868                 return;
 869         }
 870
 871         TYPESAFE_QSORT(res->msgs, res->count, dns_server_sort_zones);
 872
 873         for (i=0; i < res->count; i++) {
 874                 struct dns_server_zone *z;
 875
 876                 z = talloc_zero(dns, struct dns_server_zone);
 877                 if (z == NULL) {
 878                         task_server_terminate(task, "dns failed to allocate memory", true);
 879                 }
 880
 881                 z->name = ldb_msg_find_attr_as_string(res->msgs[i], "name", NULL);
 882                 z->dn = talloc_move(z, &res->msgs[i]->dn);
 883                 /*
 884                  * Ignore the RootDNSServers zone and zones that we don't support yet
 885                  * RootDNSServers should never be returned (Windows DNS server don't)
 886                  * ..TrustAnchors should never be returned as is, (Windows returns
 887                  * TrustAnchors) and for the moment we don't support DNSSEC so we'd better
 888                  * not return this zone.
 889                  */
 890                 if ((strcmp(z->name, "RootDNSServers") == 0) ||
 891                     (strcmp(z->name, "..TrustAnchors") == 0))
 892                 {
 893                         DEBUG(10, ("Ignoring zone %s\n", z->name));
 894                         talloc_free(z);
 895                         continue;
 896                 }
 897                 DLIST_ADD_END(dns->zones, z, NULL);
 898         }
 899
 900         status = dns_startup_interfaces(dns, ifaces);
 901         if (!NT_STATUS_IS_OK(status)) {
 902                 task_server_terminate(task, "dns failed to setup interfaces", true);
 903                 return;
 904         }
 905 }
 906
 907 NTSTATUS server_service_dns_init(void)
 908 {
 909         return register_server_service("dns", dns_task_init);
 910 }