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 "samba/service_task.h"
  24 #include "samba/service.h"
  25 #include "samba/service_stream.h"
  26 #include "samba/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 #include "librpc/gen_ndr/ndr_irpc.h"
  49 #include "lib/messaging/irpc.h"
  50 #include "libds/common/roles.h"
  51
  52 #undef DBGC_CLASS
  53 #define DBGC_CLASS DBGC_DNS
  54
  55 NTSTATUS server_service_dns_init(TALLOC_CTX *);
  56
  57 /* hold information about one dns socket */
  58 struct dns_socket {
  59         struct dns_server *dns;
  60         struct tsocket_address *local_address;
  61 };
  62
  63 struct dns_udp_socket {
  64         struct dns_socket *dns_socket;
  65         struct tdgram_context *dgram;
  66         struct tevent_queue *send_queue;
  67 };
  68
  69 /*
  70   state of an open tcp connection
  71 */
  72 struct dns_tcp_connection {
  73         /* stream connection we belong to */
  74         struct stream_connection *conn;
  75
  76         /* the dns_server the connection belongs to */
  77         struct dns_socket *dns_socket;
  78
  79         struct tstream_context *tstream;
  80
  81         struct tevent_queue *send_queue;
  82 };
  83
  84 static void dns_tcp_terminate_connection(struct dns_tcp_connection *dnsconn, const char *reason)
  85 {
  86         stream_terminate_connection(dnsconn->conn, reason);
  87 }
  88
  89 static void dns_tcp_recv(struct stream_connection *conn, uint16_t flags)
  90 {
  91         struct dns_tcp_connection *dnsconn = talloc_get_type(conn->private_data,
  92                                                              struct dns_tcp_connection);
  93         /* this should never be triggered! */
  94         dns_tcp_terminate_connection(dnsconn, "dns_tcp_recv: called");
  95 }
  96
  97 static void dns_tcp_send(struct stream_connection *conn, uint16_t flags)
  98 {
  99         struct dns_tcp_connection *dnsconn = talloc_get_type(conn->private_data,
 100                                                              struct dns_tcp_connection);
 101         /* this should never be triggered! */
 102         dns_tcp_terminate_connection(dnsconn, "dns_tcp_send: called");
 103 }
 104
 105 struct dns_process_state {
 106         DATA_BLOB *in;
 107         struct dns_server *dns;
 108         struct dns_name_packet in_packet;
 109         struct dns_request_state state;
 110         WERROR dns_err;
 111         struct dns_name_packet out_packet;
 112         DATA_BLOB out;
 113 };
 114
 115 static void dns_process_done(struct tevent_req *subreq);
 116
 117 static struct tevent_req *dns_process_send(TALLOC_CTX *mem_ctx,
 118                                            struct tevent_context *ev,
 119                                            struct dns_server *dns,
 120                                            const struct tsocket_address *remote_address,
 121                                            const struct tsocket_address *local_address,
 122                                            DATA_BLOB *in)
 123 {
 124         struct tevent_req *req, *subreq;
 125         struct dns_process_state *state;
 126         enum ndr_err_code ndr_err;
 127         WERROR ret;
 128         const char **forwarder = lpcfg_dns_forwarder(dns->task->lp_ctx);
 129         req = tevent_req_create(mem_ctx, &state, struct dns_process_state);
 130         if (req == NULL) {
 131                 return NULL;
 132         }
 133         state->state.mem_ctx = state;
 134         state->in = in;
 135
 136         state->dns = dns;
 137
 138         if (in->length < 12) {
 139                 tevent_req_werror(req, WERR_INVALID_PARAMETER);
 140                 return tevent_req_post(req, ev);
 141         }
 142         dump_data_dbgc(DBGC_DNS, 8, in->data, in->length);
 143
 144         ndr_err = ndr_pull_struct_blob(
 145                 in, state, &state->in_packet,
 146                 (ndr_pull_flags_fn_t)ndr_pull_dns_name_packet);
 147
 148         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 149                 DBG_NOTICE("ndr_pull_dns_name_packet() failed with %s\n",
 150                            ndr_map_error2string(ndr_err));
 151                 state->dns_err = DNS_ERR(FORMAT_ERROR);
 152                 tevent_req_done(req);
 153                 return tevent_req_post(req, ev);
 154         }
 155         if (DEBUGLVLC(DBGC_DNS, 8)) {
 156                 NDR_PRINT_DEBUGC(DBGC_DNS, dns_name_packet, &state->in_packet);
 157         }
 158
 159         if (state->in_packet.operation & DNS_FLAG_REPLY) {
 160                 DBG_INFO("Won't reply to replies.\n");
 161                 tevent_req_werror(req, WERR_INVALID_PARAMETER);
 162                 return tevent_req_post(req, ev);
 163         }
 164
 165         state->state.flags = state->in_packet.operation;
 166         state->state.flags |= DNS_FLAG_REPLY;
 167
 168         state->state.local_address = local_address;
 169         state->state.remote_address = remote_address;
 170
 171         if (forwarder && *forwarder && **forwarder) {
 172                 state->state.flags |= DNS_FLAG_RECURSION_AVAIL;
 173         }
 174
 175         state->out_packet = state->in_packet;
 176
 177         ret = dns_verify_tsig(dns, state, &state->state,
 178                               &state->out_packet, in);
 179         if (!W_ERROR_IS_OK(ret)) {
 180                 DBG_INFO("dns_verify_tsig() failed with %s\n",
 181                          win_errstr(ret));
 182                 state->dns_err = ret;
 183                 tevent_req_done(req);
 184                 return tevent_req_post(req, ev);
 185         }
 186
 187         switch (state->in_packet.operation & DNS_OPCODE) {
 188         case DNS_OPCODE_QUERY:
 189                 subreq = dns_server_process_query_send(
 190                         state, ev, dns,
 191                         &state->state, &state->in_packet);
 192                 if (tevent_req_nomem(subreq, req)) {
 193                         return tevent_req_post(req, ev);
 194                 }
 195                 tevent_req_set_callback(subreq, dns_process_done, req);
 196                 return req;
 197         case DNS_OPCODE_UPDATE:
 198                 ret = dns_server_process_update(
 199                         dns, &state->state, state, &state->in_packet,
 200                         &state->out_packet.answers, &state->out_packet.ancount,
 201                         &state->out_packet.nsrecs,  &state->out_packet.nscount,
 202                         &state->out_packet.additional,
 203                         &state->out_packet.arcount);
 204                 DBG_DEBUG("dns_server_process_update(): %s\n",
 205                           win_errstr(ret));
 206                 break;
 207         default:
 208                 ret = WERR_DNS_ERROR_RCODE_NOT_IMPLEMENTED;
 209                 DBG_NOTICE("OPCODE[0x%x]: %s\n",
 210                            (state->in_packet.operation & DNS_OPCODE),
 211                            win_errstr(ret));
 212         }
 213         state->dns_err = ret;
 214         tevent_req_done(req);
 215         return tevent_req_post(req, ev);
 216 }
 217
 218 static void dns_process_done(struct tevent_req *subreq)
 219 {
 220         struct tevent_req *req = tevent_req_callback_data(
 221                 subreq, struct tevent_req);
 222         struct dns_process_state *state = tevent_req_data(
 223                 req, struct dns_process_state);
 224         WERROR ret;
 225
 226         ret = dns_server_process_query_recv(
 227                 subreq, state,
 228                 &state->out_packet.answers, &state->out_packet.ancount,
 229                 &state->out_packet.nsrecs,  &state->out_packet.nscount,
 230                 &state->out_packet.additional, &state->out_packet.arcount);
 231         TALLOC_FREE(subreq);
 232
 233         DBG_DEBUG("dns_server_process_query_recv(): %s\n",
 234                   win_errstr(ret));
 235         state->dns_err = ret;
 236         tevent_req_done(req);
 237 }
 238
 239 static WERROR dns_process_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 240                                DATA_BLOB *out)
 241 {
 242         struct dns_process_state *state = tevent_req_data(
 243                 req, struct dns_process_state);
 244         enum ndr_err_code ndr_err;
 245         uint16_t dns_err;
 246         WERROR ret;
 247
 248         if (tevent_req_is_werror(req, &ret)) {
 249                 DBG_NOTICE("ERROR: %s from %s\n", win_errstr(ret),
 250                            tevent_req_print(state, req));
 251                 return ret;
 252         }
 253         dns_err = werr_to_dns_err(state->dns_err);
 254         if ((dns_err != DNS_RCODE_OK) &&
 255             (dns_err != DNS_RCODE_NXDOMAIN) &&
 256             (dns_err != DNS_RCODE_NOTAUTH))
 257         {
 258                 DBG_INFO("FAILURE: %s from %s\n",
 259                          win_errstr(state->dns_err),
 260                          tevent_req_print(state, req));
 261                 goto drop;
 262         }
 263         if (dns_err != DNS_RCODE_OK) {
 264                 DBG_DEBUG("INFO: %s from %s\n",
 265                           win_errstr(state->dns_err),
 266                           tevent_req_print(state, req));
 267                 state->out_packet.operation |= dns_err;
 268         } else {
 269                 DBG_DEBUG("OK: %s\n",
 270                           tevent_req_print(state, req));
 271         }
 272         state->out_packet.operation |= state->state.flags;
 273
 274         if (state->state.sign) {
 275                 ret = dns_sign_tsig(state->dns, mem_ctx, &state->state,
 276                                     &state->out_packet, 0);
 277                 if (!W_ERROR_IS_OK(ret)) {
 278                         DBG_WARNING("dns_sign_tsig() failed %s\n",
 279                                     win_errstr(ret));
 280                         dns_err = DNS_RCODE_SERVFAIL;
 281                         goto drop;
 282                 }
 283         }
 284
 285         if (DEBUGLVLC(DBGC_DNS, 8)) {
 286                 NDR_PRINT_DEBUGC(DBGC_DNS, dns_name_packet, &state->out_packet);
 287         }
 288
 289         ndr_err = ndr_push_struct_blob(
 290                 out, mem_ctx, &state->out_packet,
 291                 (ndr_push_flags_fn_t)ndr_push_dns_name_packet);
 292         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 293                 DBG_WARNING("Failed to push packet: %s!\n",
 294                             ndr_errstr(ndr_err));
 295                 dns_err = DNS_RCODE_SERVFAIL;
 296                 goto drop;
 297         }
 298         return WERR_OK;
 299
 300 drop:
 301         *out = data_blob_talloc(mem_ctx, state->in->data, state->in->length);
 302         if (out->data == NULL) {
 303                 return WERR_NOT_ENOUGH_MEMORY;
 304         }
 305         out->data[2] |= 0x80; /* Toggle DNS_FLAG_REPLY */
 306         out->data[3] |= dns_err;
 307         return WERR_OK;
 308 }
 309
 310 struct dns_tcp_call {
 311         struct dns_tcp_connection *dns_conn;
 312         DATA_BLOB in;
 313         DATA_BLOB out;
 314         uint8_t out_hdr[4];
 315         struct iovec out_iov[2];
 316 };
 317
 318 static void dns_tcp_call_process_done(struct tevent_req *subreq);
 319 static void dns_tcp_call_writev_done(struct tevent_req *subreq);
 320
 321 static void dns_tcp_call_loop(struct tevent_req *subreq)
 322 {
 323         struct dns_tcp_connection *dns_conn = tevent_req_callback_data(subreq,
 324                                       struct dns_tcp_connection);
 325         struct dns_server *dns = dns_conn->dns_socket->dns;
 326         struct dns_tcp_call *call;
 327         NTSTATUS status;
 328
 329         call = talloc(dns_conn, struct dns_tcp_call);
 330         if (call == NULL) {
 331                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 332                                 "no memory for dns_tcp_call");
 333                 return;
 334         }
 335         call->dns_conn = dns_conn;
 336
 337         status = tstream_read_pdu_blob_recv(subreq,
 338                                             call,
 339                                             &call->in);
 340         TALLOC_FREE(subreq);
 341         if (!NT_STATUS_IS_OK(status)) {
 342                 const char *reason;
 343
 344                 reason = talloc_asprintf(call, "dns_tcp_call_loop: "
 345                                          "tstream_read_pdu_blob_recv() - %s",
 346                                          nt_errstr(status));
 347                 if (!reason) {
 348                         reason = nt_errstr(status);
 349                 }
 350
 351                 dns_tcp_terminate_connection(dns_conn, reason);
 352                 return;
 353         }
 354
 355         DEBUG(10,("Received DNS TCP packet of length %lu from %s\n",
 356                  (long) call->in.length,
 357                  tsocket_address_string(dns_conn->conn->remote_address, call)));
 358
 359         /* skip length header */
 360         call->in.data += 2;
 361         call->in.length -= 2;
 362
 363         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 364                                   dns_conn->conn->remote_address,
 365                                   dns_conn->conn->local_address,
 366                                   &call->in);
 367         if (subreq == NULL) {
 368                 dns_tcp_terminate_connection(
 369                         dns_conn, "dns_tcp_call_loop: dns_process_send "
 370                         "failed\n");
 371                 return;
 372         }
 373         tevent_req_set_callback(subreq, dns_tcp_call_process_done, call);
 374
 375         /*
 376          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 377          * tstream_full_request_u16 provides the pdu length then.
 378          */
 379         subreq = tstream_read_pdu_blob_send(dns_conn,
 380                                             dns_conn->conn->event.ctx,
 381                                             dns_conn->tstream,
 382                                             2, /* initial_read_size */
 383                                             tstream_full_request_u16,
 384                                             dns_conn);
 385         if (subreq == NULL) {
 386                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 387                                 "no memory for tstream_read_pdu_blob_send");
 388                 return;
 389         }
 390         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 391 }
 392
 393 static void dns_tcp_call_process_done(struct tevent_req *subreq)
 394 {
 395         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 396                         struct dns_tcp_call);
 397         struct dns_tcp_connection *dns_conn = call->dns_conn;
 398         WERROR err;
 399
 400         err = dns_process_recv(subreq, call, &call->out);
 401         TALLOC_FREE(subreq);
 402         if (!W_ERROR_IS_OK(err)) {
 403                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 404                 dns_tcp_terminate_connection(dns_conn,
 405                                 "dns_tcp_call_loop: process function failed");
 406                 return;
 407         }
 408
 409         /* First add the length of the out buffer */
 410         RSSVAL(call->out_hdr, 0, call->out.length);
 411         call->out_iov[0].iov_base = (char *) call->out_hdr;
 412         call->out_iov[0].iov_len = 2;
 413
 414         call->out_iov[1].iov_base = (char *) call->out.data;
 415         call->out_iov[1].iov_len = call->out.length;
 416
 417         subreq = tstream_writev_queue_send(call,
 418                                            dns_conn->conn->event.ctx,
 419                                            dns_conn->tstream,
 420                                            dns_conn->send_queue,
 421                                            call->out_iov, 2);
 422         if (subreq == NULL) {
 423                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 424                                 "no memory for tstream_writev_queue_send");
 425                 return;
 426         }
 427         tevent_req_set_callback(subreq, dns_tcp_call_writev_done, call);
 428 }
 429
 430 static void dns_tcp_call_writev_done(struct tevent_req *subreq)
 431 {
 432         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 433                         struct dns_tcp_call);
 434         int sys_errno;
 435         int rc;
 436
 437         rc = tstream_writev_queue_recv(subreq, &sys_errno);
 438         TALLOC_FREE(subreq);
 439         if (rc == -1) {
 440                 const char *reason;
 441
 442                 reason = talloc_asprintf(call, "dns_tcp_call_writev_done: "
 443                                          "tstream_writev_queue_recv() - %d:%s",
 444                                          sys_errno, strerror(sys_errno));
 445                 if (!reason) {
 446                         reason = "dns_tcp_call_writev_done: tstream_writev_queue_recv() failed";
 447                 }
 448
 449                 dns_tcp_terminate_connection(call->dns_conn, reason);
 450                 return;
 451         }
 452
 453         /* We don't care about errors */
 454
 455         talloc_free(call);
 456 }
 457
 458 /*
 459   called when we get a new connection
 460 */
 461 static void dns_tcp_accept(struct stream_connection *conn)
 462 {
 463         struct dns_socket *dns_socket;
 464         struct dns_tcp_connection *dns_conn;
 465         struct tevent_req *subreq;
 466         int rc;
 467
 468         dns_conn = talloc_zero(conn, struct dns_tcp_connection);
 469         if (dns_conn == NULL) {
 470                 stream_terminate_connection(conn,
 471                                 "dns_tcp_accept: out of memory");
 472                 return;
 473         }
 474
 475         dns_conn->send_queue = tevent_queue_create(conn, "dns_tcp_accept");
 476         if (dns_conn->send_queue == NULL) {
 477                 stream_terminate_connection(conn,
 478                                 "dns_tcp_accept: out of memory");
 479                 return;
 480         }
 481
 482         dns_socket = talloc_get_type(conn->private_data, struct dns_socket);
 483
 484         TALLOC_FREE(conn->event.fde);
 485
 486         rc = tstream_bsd_existing_socket(dns_conn,
 487                         socket_get_fd(conn->socket),
 488                         &dns_conn->tstream);
 489         if (rc < 0) {
 490                 stream_terminate_connection(conn,
 491                                 "dns_tcp_accept: out of memory");
 492                 return;
 493         }
 494         /* as server we want to fail early */
 495         tstream_bsd_fail_readv_first_error(dns_conn->tstream, true);
 496
 497         dns_conn->conn = conn;
 498         dns_conn->dns_socket = dns_socket;
 499         conn->private_data = dns_conn;
 500
 501         /*
 502          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 503          * tstream_full_request_u16 provides the pdu length then.
 504          */
 505         subreq = tstream_read_pdu_blob_send(dns_conn,
 506                                             dns_conn->conn->event.ctx,
 507                                             dns_conn->tstream,
 508                                             2, /* initial_read_size */
 509                                             tstream_full_request_u16,
 510                                             dns_conn);
 511         if (subreq == NULL) {
 512                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_accept: "
 513                                 "no memory for tstream_read_pdu_blob_send");
 514                 return;
 515         }
 516         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 517 }
 518
 519 static const struct stream_server_ops dns_tcp_stream_ops = {
 520         .name                   = "dns_tcp",
 521         .accept_connection      = dns_tcp_accept,
 522         .recv_handler           = dns_tcp_recv,
 523         .send_handler           = dns_tcp_send
 524 };
 525
 526 struct dns_udp_call {
 527         struct dns_udp_socket *sock;
 528         struct tsocket_address *src;
 529         DATA_BLOB in;
 530         DATA_BLOB out;
 531 };
 532
 533 static void dns_udp_call_process_done(struct tevent_req *subreq);
 534 static void dns_udp_call_sendto_done(struct tevent_req *subreq);
 535
 536 static void dns_udp_call_loop(struct tevent_req *subreq)
 537 {
 538         struct dns_udp_socket *sock = tevent_req_callback_data(subreq,
 539                                       struct dns_udp_socket);
 540         struct dns_server *dns = sock->dns_socket->dns;
 541         struct dns_udp_call *call;
 542         uint8_t *buf;
 543         ssize_t len;
 544         int sys_errno;
 545
 546         call = talloc(sock, struct dns_udp_call);
 547         if (call == NULL) {
 548                 talloc_free(call);
 549                 goto done;
 550         }
 551         call->sock = sock;
 552
 553         len = tdgram_recvfrom_recv(subreq, &sys_errno,
 554                                    call, &buf, &call->src);
 555         TALLOC_FREE(subreq);
 556         if (len == -1) {
 557                 talloc_free(call);
 558                 goto done;
 559         }
 560
 561         call->in.data = buf;
 562         call->in.length = len;
 563
 564         DEBUG(10,("Received DNS UDP packet of length %lu from %s\n",
 565                  (long)call->in.length,
 566                  tsocket_address_string(call->src, call)));
 567
 568         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 569                                   call->src,
 570                                   sock->dns_socket->local_address,
 571                                   &call->in);
 572         if (subreq == NULL) {
 573                 TALLOC_FREE(call);
 574                 goto done;
 575         }
 576         tevent_req_set_callback(subreq, dns_udp_call_process_done, call);
 577
 578 done:
 579         subreq = tdgram_recvfrom_send(sock,
 580                                       sock->dns_socket->dns->task->event_ctx,
 581                                       sock->dgram);
 582         if (subreq == NULL) {
 583                 task_server_terminate(sock->dns_socket->dns->task,
 584                                       "no memory for tdgram_recvfrom_send",
 585                                       true);
 586                 return;
 587         }
 588         tevent_req_set_callback(subreq, dns_udp_call_loop, sock);
 589 }
 590
 591 static void dns_udp_call_process_done(struct tevent_req *subreq)
 592 {
 593         struct dns_udp_call *call = tevent_req_callback_data(
 594                 subreq, struct dns_udp_call);
 595         struct dns_udp_socket *sock = call->sock;
 596         struct dns_server *dns = sock->dns_socket->dns;
 597         WERROR err;
 598
 599         err = dns_process_recv(subreq, call, &call->out);
 600         TALLOC_FREE(subreq);
 601         if (!W_ERROR_IS_OK(err)) {
 602                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 603                 TALLOC_FREE(call);
 604                 return;
 605         }
 606
 607         subreq = tdgram_sendto_queue_send(call,
 608                                           dns->task->event_ctx,
 609                                           sock->dgram,
 610                                           sock->send_queue,
 611                                           call->out.data,
 612                                           call->out.length,
 613                                           call->src);
 614         if (subreq == NULL) {
 615                 talloc_free(call);
 616                 return;
 617         }
 618         tevent_req_set_callback(subreq, dns_udp_call_sendto_done, call);
 619
 620 }
 621 static void dns_udp_call_sendto_done(struct tevent_req *subreq)
 622 {
 623         struct dns_udp_call *call = tevent_req_callback_data(subreq,
 624                                        struct dns_udp_call);
 625         int sys_errno;
 626
 627         tdgram_sendto_queue_recv(subreq, &sys_errno);
 628
 629         /* We don't care about errors */
 630
 631         talloc_free(call);
 632 }
 633
 634 /*
 635   start listening on the given address
 636 */
 637 static NTSTATUS dns_add_socket(struct dns_server *dns,
 638                                const struct model_ops *model_ops,
 639                                const char *name,
 640                                const char *address,
 641                                uint16_t port)
 642 {
 643         struct dns_socket *dns_socket;
 644         struct dns_udp_socket *dns_udp_socket;
 645         struct tevent_req *udpsubreq;
 646         NTSTATUS status;
 647         int ret;
 648
 649         dns_socket = talloc(dns, struct dns_socket);
 650         NT_STATUS_HAVE_NO_MEMORY(dns_socket);
 651
 652         dns_socket->dns = dns;
 653
 654         ret = tsocket_address_inet_from_strings(dns_socket, "ip",
 655                                                 address, port,
 656                                                 &dns_socket->local_address);
 657         if (ret != 0) {
 658                 status = map_nt_error_from_unix_common(errno);
 659                 return status;
 660         }
 661
 662         status = stream_setup_socket(dns->task,
 663                                      dns->task->event_ctx,
 664                                      dns->task->lp_ctx,
 665                                      model_ops,
 666                                      &dns_tcp_stream_ops,
 667                                      "ip", address, &port,
 668                                      lpcfg_socket_options(dns->task->lp_ctx),
 669                                      dns_socket,
 670                                      dns->task->process_context);
 671         if (!NT_STATUS_IS_OK(status)) {
 672                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 673                          address, port, nt_errstr(status)));
 674                 talloc_free(dns_socket);
 675                 return status;
 676         }
 677
 678         dns_udp_socket = talloc(dns_socket, struct dns_udp_socket);
 679         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket);
 680
 681         dns_udp_socket->dns_socket = dns_socket;
 682
 683         ret = tdgram_inet_udp_socket(dns_socket->local_address,
 684                                      NULL,
 685                                      dns_udp_socket,
 686                                      &dns_udp_socket->dgram);
 687         if (ret != 0) {
 688                 status = map_nt_error_from_unix_common(errno);
 689                 DEBUG(0,("Failed to bind to %s:%u UDP - %s\n",
 690                          address, port, nt_errstr(status)));
 691                 return status;
 692         }
 693
 694         dns_udp_socket->send_queue = tevent_queue_create(dns_udp_socket,
 695                                                          "dns_udp_send_queue");
 696         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket->send_queue);
 697
 698         udpsubreq = tdgram_recvfrom_send(dns_udp_socket,
 699                                          dns->task->event_ctx,
 700                                          dns_udp_socket->dgram);
 701         NT_STATUS_HAVE_NO_MEMORY(udpsubreq);
 702         tevent_req_set_callback(udpsubreq, dns_udp_call_loop, dns_udp_socket);
 703
 704         return NT_STATUS_OK;
 705 }
 706
 707 /*
 708   setup our listening sockets on the configured network interfaces
 709 */
 710 static NTSTATUS dns_startup_interfaces(struct dns_server *dns,
 711                                        struct interface *ifaces,
 712                                        const struct model_ops *model_ops)
 713 {
 714         size_t num_interfaces;
 715         TALLOC_CTX *tmp_ctx = talloc_new(dns);
 716         NTSTATUS status;
 717         int i;
 718
 719         if (ifaces != NULL) {
 720                 num_interfaces = iface_list_count(ifaces);
 721
 722                 for (i=0; i<num_interfaces; i++) {
 723                         const char *address = talloc_strdup(tmp_ctx,
 724                                                             iface_list_n_ip(ifaces, i));
 725
 726                         status = dns_add_socket(dns, model_ops, "dns", address,
 727                                                 lpcfg_dns_port(dns->task->lp_ctx));
 728                         NT_STATUS_NOT_OK_RETURN(status);
 729                 }
 730         } else {
 731                 size_t num_binds = 0;
 732                 char **wcard;
 733                 wcard = iface_list_wildcard(tmp_ctx);
 734                 if (wcard == NULL) {
 735                         DEBUG(0, ("No wildcard address available\n"));
 736                         return NT_STATUS_INTERNAL_ERROR;
 737                 }
 738                 for (i = 0; wcard[i] != NULL; i++) {
 739                         status = dns_add_socket(dns, model_ops, "dns", wcard[i],
 740                                                 lpcfg_dns_port(dns->task->lp_ctx));
 741                         if (NT_STATUS_IS_OK(status)) {
 742                                 num_binds++;
 743                         }
 744                 }
 745                 if (num_binds == 0) {
 746                         talloc_free(tmp_ctx);
 747                         return NT_STATUS_INVALID_PARAMETER_MIX;
 748                 }
 749         }
 750
 751         talloc_free(tmp_ctx);
 752
 753         return NT_STATUS_OK;
 754 }
 755
 756 static struct dns_server_tkey_store *tkey_store_init(TALLOC_CTX *mem_ctx,
 757                                                      uint16_t size)
 758 {
 759         struct dns_server_tkey_store *buffer = talloc_zero(mem_ctx,
 760                                                 struct dns_server_tkey_store);
 761
 762         if (buffer == NULL) {
 763                 return NULL;
 764         }
 765
 766         buffer->size = size;
 767         buffer->next_idx = 0;
 768
 769         buffer->tkeys = talloc_zero_array(buffer, struct dns_server_tkey *, size);
 770         if (buffer->tkeys == NULL) {
 771                 TALLOC_FREE(buffer);
 772         }
 773
 774         return buffer;
 775 }
 776
 777 static NTSTATUS dns_server_reload_zones(struct dns_server *dns)
 778 {
 779         NTSTATUS status;
 780         struct dns_server_zone *new_list = NULL;
 781         struct dns_server_zone *old_list = dns->zones;
 782         struct dns_server_zone *old_zone;
 783         status = dns_common_zones(dns->samdb, dns, NULL, &new_list);
 784         if (!NT_STATUS_IS_OK(status)) {
 785                 return status;
 786         }
 787         dns->zones = new_list;
 788         while ((old_zone = DLIST_TAIL(old_list)) != NULL) {
 789                 DLIST_REMOVE(old_list, old_zone);
 790                 talloc_free(old_zone);
 791         }
 792
 793         return NT_STATUS_OK;
 794 }
 795
 796 /**
 797  * Called when the internal DNS server should reload the zones from DB, for
 798  * example, when zones are added or deleted through RPC or replicated by
 799  * inbound DRS.
 800  */
 801 static NTSTATUS dns_reload_zones(struct irpc_message *msg,
 802                                  struct dnssrv_reload_dns_zones *r)
 803 {
 804         struct dns_server *dns;
 805
 806         dns = talloc_get_type(msg->private_data, struct dns_server);
 807         if (dns == NULL) {
 808                 r->out.result = NT_STATUS_INTERNAL_ERROR;
 809                 return NT_STATUS_INTERNAL_ERROR;
 810         }
 811
 812         r->out.result = dns_server_reload_zones(dns);
 813
 814         return NT_STATUS_OK;
 815 }
 816
 817 static NTSTATUS dns_task_init(struct task_server *task)
 818 {
 819         struct dns_server *dns;
 820         NTSTATUS status;
 821         struct interface *ifaces = NULL;
 822         int ret;
 823         static const char * const attrs_none[] = { NULL};
 824         struct ldb_message *dns_acc;
 825         const char *dns_hostname = NULL;
 826         char *dns_spn;
 827         bool ok;
 828
 829         switch (lpcfg_server_role(task->lp_ctx)) {
 830         case ROLE_STANDALONE:
 831                 task_server_terminate(task, "dns: no DNS required in standalone configuration", false);
 832                 return NT_STATUS_INVALID_DOMAIN_ROLE;
 833         case ROLE_DOMAIN_MEMBER:
 834                 task_server_terminate(task, "dns: no DNS required in member server configuration", false);
 835                 return NT_STATUS_INVALID_DOMAIN_ROLE;
 836         case ROLE_ACTIVE_DIRECTORY_DC:
 837                 /* Yes, we want a DNS */
 838                 break;
 839         }
 840
 841         if (lpcfg_interfaces(task->lp_ctx) && lpcfg_bind_interfaces_only(task->lp_ctx)) {
 842                 load_interface_list(task, task->lp_ctx, &ifaces);
 843
 844                 if (iface_list_count(ifaces) == 0) {
 845                         task_server_terminate(task, "dns: no network interfaces configured", false);
 846                         return NT_STATUS_UNSUCCESSFUL;
 847                 }
 848         }
 849
 850         task_server_set_title(task, "task[dns]");
 851
 852         dns = talloc_zero(task, struct dns_server);
 853         if (dns == NULL) {
 854                 task_server_terminate(task, "dns: out of memory", true);
 855                 return NT_STATUS_NO_MEMORY;
 856         }
 857
 858         dns->task = task;
 859
 860         dns->server_credentials = cli_credentials_init(dns);
 861         if (!dns->server_credentials) {
 862                 task_server_terminate(task, "Failed to init server credentials\n", true);
 863                 return NT_STATUS_UNSUCCESSFUL;
 864         }
 865
 866         dns->samdb = samdb_connect(dns,
 867                                    dns->task->event_ctx,
 868                                    dns->task->lp_ctx,
 869                                    system_session(dns->task->lp_ctx),
 870                                    NULL,
 871                                    0);
 872         if (!dns->samdb) {
 873                 task_server_terminate(task, "dns: samdb_connect failed", true);
 874                 return NT_STATUS_UNSUCCESSFUL;
 875         }
 876
 877         ok = cli_credentials_set_conf(dns->server_credentials, task->lp_ctx);
 878         if (!ok) {
 879                 task_server_terminate(task,
 880                                       "dns: failed to load smb.conf",
 881                                       true);
 882                 return NT_STATUS_UNSUCCESSFUL;
 883         }
 884
 885         dns_hostname = lpcfg_dns_hostname(task->lp_ctx);
 886         if (dns_hostname == NULL) {
 887                 return NT_STATUS_NO_MEMORY;
 888         }
 889         dns_spn = talloc_asprintf(dns, "DNS/%s", dns_hostname);
 890         if (dns_spn == NULL) {
 891                 return NT_STATUS_NO_MEMORY;
 892         }
 893
 894         ret = dsdb_search_one(dns->samdb, dns, &dns_acc,
 895                               ldb_get_default_basedn(dns->samdb), LDB_SCOPE_SUBTREE,
 896                               attrs_none, 0, "(servicePrincipalName=%s)",
 897                               dns_spn);
 898         if (ret == LDB_SUCCESS) {
 899                 TALLOC_FREE(dns_acc);
 900                 if (!dns_spn) {
 901                         task_server_terminate(task, "dns: talloc_asprintf failed", true);
 902                         return NT_STATUS_UNSUCCESSFUL;
 903                 }
 904                 status = cli_credentials_set_stored_principal(dns->server_credentials, task->lp_ctx, dns_spn);
 905                 if (!NT_STATUS_IS_OK(status)) {
 906                         task_server_terminate(task,
 907                                               talloc_asprintf(task, "Failed to obtain server credentials for DNS, "
 908                                                               "despite finding it in the samdb! %s\n",
 909                                                               nt_errstr(status)),
 910                                               true);
 911                         return status;
 912                 }
 913         } else {
 914                 TALLOC_FREE(dns_spn);
 915                 status = cli_credentials_set_machine_account(dns->server_credentials, task->lp_ctx);
 916                 if (!NT_STATUS_IS_OK(status)) {
 917                         task_server_terminate(task,
 918                                               talloc_asprintf(task, "Failed to obtain server credentials, perhaps a standalone server?: %s\n",
 919                                                               nt_errstr(status)),
 920                                               true);
 921                         return status;
 922                 }
 923         }
 924
 925         dns->tkeys = tkey_store_init(dns, TKEY_BUFFER_SIZE);
 926         if (!dns->tkeys) {
 927                 task_server_terminate(task, "Failed to allocate tkey storage\n", true);
 928                 return NT_STATUS_NO_MEMORY;
 929         }
 930
 931         status = dns_server_reload_zones(dns);
 932         if (!NT_STATUS_IS_OK(status)) {
 933                 task_server_terminate(task, "dns: failed to load DNS zones", true);
 934                 return status;
 935         }
 936
 937         status = dns_startup_interfaces(dns, ifaces, task->model_ops);
 938         if (!NT_STATUS_IS_OK(status)) {
 939                 task_server_terminate(task, "dns failed to setup interfaces", true);
 940                 return status;
 941         }
 942
 943         /* Setup the IRPC interface and register handlers */
 944         status = irpc_add_name(task->msg_ctx, "dnssrv");
 945         if (!NT_STATUS_IS_OK(status)) {
 946                 task_server_terminate(task, "dns: failed to register IRPC name", true);
 947                 return status;
 948         }
 949
 950         status = IRPC_REGISTER(task->msg_ctx, irpc, DNSSRV_RELOAD_DNS_ZONES,
 951                                dns_reload_zones, dns);
 952         if (!NT_STATUS_IS_OK(status)) {
 953                 task_server_terminate(task, "dns: failed to setup reload handler", true);
 954                 return status;
 955         }
 956         return NT_STATUS_OK;
 957 }
 958
 959 NTSTATUS server_service_dns_init(TALLOC_CTX *ctx)
 960 {
 961         static const struct service_details details = {
 962                 .inhibit_fork_on_accept = true,
 963                 .inhibit_pre_fork = true,
 964                 .task_init = dns_task_init,
 965                 .post_fork = NULL
 966         };
 967         return register_server_service(ctx, "dns", &details);
 968 }