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 #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(void);
  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         uint16_t 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                                            DATA_BLOB *in)
 121 {
 122         struct tevent_req *req, *subreq;
 123         struct dns_process_state *state;
 124         enum ndr_err_code ndr_err;
 125         WERROR ret;
 126         const char **forwarder = lpcfg_dns_forwarder(dns->task->lp_ctx);
 127         req = tevent_req_create(mem_ctx, &state, struct dns_process_state);
 128         if (req == NULL) {
 129                 return NULL;
 130         }
 131         state->state.mem_ctx = state;
 132         state->in = in;
 133
 134         state->dns = dns;
 135
 136         if (in->length < 12) {
 137                 tevent_req_werror(req, WERR_INVALID_PARAMETER);
 138                 return tevent_req_post(req, ev);
 139         }
 140         dump_data_dbgc(DBGC_DNS, 8, in->data, in->length);
 141
 142         ndr_err = ndr_pull_struct_blob(
 143                 in, state, &state->in_packet,
 144                 (ndr_pull_flags_fn_t)ndr_pull_dns_name_packet);
 145
 146         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 147                 state->dns_err = DNS_RCODE_FORMERR;
 148                 tevent_req_done(req);
 149                 return tevent_req_post(req, ev);
 150         }
 151         if (DEBUGLVLC(DBGC_DNS, 8)) {
 152                 NDR_PRINT_DEBUGC(DBGC_DNS, dns_name_packet, &state->in_packet);
 153         }
 154
 155         if (state->in_packet.operation & DNS_FLAG_REPLY) {
 156                 DEBUG(1, ("Won't reply to replies.\n"));
 157                 tevent_req_werror(req, WERR_INVALID_PARAMETER);
 158                 return tevent_req_post(req, ev);
 159         }
 160
 161         state->state.flags = state->in_packet.operation;
 162         state->state.flags |= DNS_FLAG_REPLY;
 163
 164
 165         if (forwarder && *forwarder && **forwarder) {
 166                 state->state.flags |= DNS_FLAG_RECURSION_AVAIL;
 167         }
 168
 169         state->out_packet = state->in_packet;
 170
 171         ret = dns_verify_tsig(dns, state, &state->state, &state->out_packet, in);
 172         if (!W_ERROR_IS_OK(ret)) {
 173                 state->dns_err = werr_to_dns_err(ret);
 174                 tevent_req_done(req);
 175                 return tevent_req_post(req, ev);
 176         }
 177
 178         switch (state->in_packet.operation & DNS_OPCODE) {
 179         case DNS_OPCODE_QUERY:
 180                 subreq = dns_server_process_query_send(
 181                         state, ev, dns, &state->state, &state->in_packet);
 182                 if (tevent_req_nomem(subreq, req)) {
 183                         return tevent_req_post(req, ev);
 184                 }
 185                 tevent_req_set_callback(subreq, dns_process_done, req);
 186                 return req;
 187         case DNS_OPCODE_UPDATE:
 188                 ret = dns_server_process_update(
 189                         dns, &state->state, state, &state->in_packet,
 190                         &state->out_packet.answers, &state->out_packet.ancount,
 191                         &state->out_packet.nsrecs,  &state->out_packet.nscount,
 192                         &state->out_packet.additional,
 193                         &state->out_packet.arcount);
 194                 break;
 195         default:
 196                 ret = WERR_DNS_ERROR_RCODE_NOT_IMPLEMENTED;
 197         }
 198         if (!W_ERROR_IS_OK(ret)) {
 199                 state->dns_err = werr_to_dns_err(ret);
 200         }
 201         tevent_req_done(req);
 202         return tevent_req_post(req, ev);
 203 }
 204
 205 static void dns_process_done(struct tevent_req *subreq)
 206 {
 207         struct tevent_req *req = tevent_req_callback_data(
 208                 subreq, struct tevent_req);
 209         struct dns_process_state *state = tevent_req_data(
 210                 req, struct dns_process_state);
 211         WERROR ret;
 212
 213         ret = dns_server_process_query_recv(
 214                 subreq, state,
 215                 &state->out_packet.answers, &state->out_packet.ancount,
 216                 &state->out_packet.nsrecs,  &state->out_packet.nscount,
 217                 &state->out_packet.additional, &state->out_packet.arcount);
 218         TALLOC_FREE(subreq);
 219
 220         if (!W_ERROR_IS_OK(ret)) {
 221                 state->dns_err = werr_to_dns_err(ret);
 222         }
 223         tevent_req_done(req);
 224 }
 225
 226 static WERROR dns_process_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 227                                DATA_BLOB *out)
 228 {
 229         struct dns_process_state *state = tevent_req_data(
 230                 req, struct dns_process_state);
 231         enum ndr_err_code ndr_err;
 232         WERROR ret;
 233
 234         if (tevent_req_is_werror(req, &ret)) {
 235                 return ret;
 236         }
 237         if ((state->dns_err != DNS_RCODE_OK) &&
 238             (state->dns_err != DNS_RCODE_NXDOMAIN) &&
 239             (state->dns_err != DNS_RCODE_NOTAUTH))
 240         {
 241                 goto drop;
 242         }
 243         if (state->dns_err != DNS_RCODE_OK) {
 244                 state->out_packet.operation |= state->dns_err;
 245         }
 246         state->out_packet.operation |= state->state.flags;
 247
 248         if (state->state.sign) {
 249                 ret = dns_sign_tsig(state->dns, mem_ctx, &state->state,
 250                                     &state->out_packet, 0);
 251                 if (!W_ERROR_IS_OK(ret)) {
 252                         state->dns_err = DNS_RCODE_SERVFAIL;
 253                         goto drop;
 254                 }
 255         }
 256
 257         if (DEBUGLVLC(DBGC_DNS, 8)) {
 258                 NDR_PRINT_DEBUGC(DBGC_DNS, dns_name_packet, &state->out_packet);
 259         }
 260
 261         ndr_err = ndr_push_struct_blob(
 262                 out, mem_ctx, &state->out_packet,
 263                 (ndr_push_flags_fn_t)ndr_push_dns_name_packet);
 264         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 265                 DEBUG(1, ("Failed to push packet: %s!\n",
 266                           ndr_errstr(ndr_err)));
 267                 state->dns_err = DNS_RCODE_SERVFAIL;
 268                 goto drop;
 269         }
 270         return WERR_OK;
 271
 272 drop:
 273         *out = data_blob_talloc(mem_ctx, state->in->data, state->in->length);
 274         if (out->data == NULL) {
 275                 return WERR_NOT_ENOUGH_MEMORY;
 276         }
 277         out->data[2] |= 0x80; /* Toggle DNS_FLAG_REPLY */
 278         out->data[3] |= state->dns_err;
 279         return WERR_OK;
 280 }
 281
 282 struct dns_tcp_call {
 283         struct dns_tcp_connection *dns_conn;
 284         DATA_BLOB in;
 285         DATA_BLOB out;
 286         uint8_t out_hdr[4];
 287         struct iovec out_iov[2];
 288 };
 289
 290 static void dns_tcp_call_process_done(struct tevent_req *subreq);
 291 static void dns_tcp_call_writev_done(struct tevent_req *subreq);
 292
 293 static void dns_tcp_call_loop(struct tevent_req *subreq)
 294 {
 295         struct dns_tcp_connection *dns_conn = tevent_req_callback_data(subreq,
 296                                       struct dns_tcp_connection);
 297         struct dns_server *dns = dns_conn->dns_socket->dns;
 298         struct dns_tcp_call *call;
 299         NTSTATUS status;
 300
 301         call = talloc(dns_conn, struct dns_tcp_call);
 302         if (call == NULL) {
 303                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 304                                 "no memory for dns_tcp_call");
 305                 return;
 306         }
 307         call->dns_conn = dns_conn;
 308
 309         status = tstream_read_pdu_blob_recv(subreq,
 310                                             call,
 311                                             &call->in);
 312         TALLOC_FREE(subreq);
 313         if (!NT_STATUS_IS_OK(status)) {
 314                 const char *reason;
 315
 316                 reason = talloc_asprintf(call, "dns_tcp_call_loop: "
 317                                          "tstream_read_pdu_blob_recv() - %s",
 318                                          nt_errstr(status));
 319                 if (!reason) {
 320                         reason = nt_errstr(status);
 321                 }
 322
 323                 dns_tcp_terminate_connection(dns_conn, reason);
 324                 return;
 325         }
 326
 327         DEBUG(10,("Received DNS TCP packet of length %lu from %s\n",
 328                  (long) call->in.length,
 329                  tsocket_address_string(dns_conn->conn->remote_address, call)));
 330
 331         /* skip length header */
 332         call->in.data += 2;
 333         call->in.length -= 2;
 334
 335         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 336                                   &call->in);
 337         if (subreq == NULL) {
 338                 dns_tcp_terminate_connection(
 339                         dns_conn, "dns_tcp_call_loop: dns_process_send "
 340                         "failed\n");
 341                 return;
 342         }
 343         tevent_req_set_callback(subreq, dns_tcp_call_process_done, call);
 344
 345         /*
 346          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 347          * packet_full_request_u16 provides the pdu length then.
 348          */
 349         subreq = tstream_read_pdu_blob_send(dns_conn,
 350                                             dns_conn->conn->event.ctx,
 351                                             dns_conn->tstream,
 352                                             2, /* initial_read_size */
 353                                             packet_full_request_u16,
 354                                             dns_conn);
 355         if (subreq == NULL) {
 356                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 357                                 "no memory for tstream_read_pdu_blob_send");
 358                 return;
 359         }
 360         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 361 }
 362
 363 static void dns_tcp_call_process_done(struct tevent_req *subreq)
 364 {
 365         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 366                         struct dns_tcp_call);
 367         struct dns_tcp_connection *dns_conn = call->dns_conn;
 368         WERROR err;
 369
 370         err = dns_process_recv(subreq, call, &call->out);
 371         TALLOC_FREE(subreq);
 372         if (!W_ERROR_IS_OK(err)) {
 373                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 374                 dns_tcp_terminate_connection(dns_conn,
 375                                 "dns_tcp_call_loop: process function failed");
 376                 return;
 377         }
 378
 379         /* First add the length of the out buffer */
 380         RSSVAL(call->out_hdr, 0, call->out.length);
 381         call->out_iov[0].iov_base = (char *) call->out_hdr;
 382         call->out_iov[0].iov_len = 2;
 383
 384         call->out_iov[1].iov_base = (char *) call->out.data;
 385         call->out_iov[1].iov_len = call->out.length;
 386
 387         subreq = tstream_writev_queue_send(call,
 388                                            dns_conn->conn->event.ctx,
 389                                            dns_conn->tstream,
 390                                            dns_conn->send_queue,
 391                                            call->out_iov, 2);
 392         if (subreq == NULL) {
 393                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 394                                 "no memory for tstream_writev_queue_send");
 395                 return;
 396         }
 397         tevent_req_set_callback(subreq, dns_tcp_call_writev_done, call);
 398 }
 399
 400 static void dns_tcp_call_writev_done(struct tevent_req *subreq)
 401 {
 402         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 403                         struct dns_tcp_call);
 404         int sys_errno;
 405         int rc;
 406
 407         rc = tstream_writev_queue_recv(subreq, &sys_errno);
 408         TALLOC_FREE(subreq);
 409         if (rc == -1) {
 410                 const char *reason;
 411
 412                 reason = talloc_asprintf(call, "dns_tcp_call_writev_done: "
 413                                          "tstream_writev_queue_recv() - %d:%s",
 414                                          sys_errno, strerror(sys_errno));
 415                 if (!reason) {
 416                         reason = "dns_tcp_call_writev_done: tstream_writev_queue_recv() failed";
 417                 }
 418
 419                 dns_tcp_terminate_connection(call->dns_conn, reason);
 420                 return;
 421         }
 422
 423         /* We don't care about errors */
 424
 425         talloc_free(call);
 426 }
 427
 428 /*
 429   called when we get a new connection
 430 */
 431 static void dns_tcp_accept(struct stream_connection *conn)
 432 {
 433         struct dns_socket *dns_socket;
 434         struct dns_tcp_connection *dns_conn;
 435         struct tevent_req *subreq;
 436         int rc;
 437
 438         dns_conn = talloc_zero(conn, struct dns_tcp_connection);
 439         if (dns_conn == NULL) {
 440                 stream_terminate_connection(conn,
 441                                 "dns_tcp_accept: out of memory");
 442                 return;
 443         }
 444
 445         dns_conn->send_queue = tevent_queue_create(conn, "dns_tcp_accept");
 446         if (dns_conn->send_queue == NULL) {
 447                 stream_terminate_connection(conn,
 448                                 "dns_tcp_accept: out of memory");
 449                 return;
 450         }
 451
 452         dns_socket = talloc_get_type(conn->private_data, struct dns_socket);
 453
 454         TALLOC_FREE(conn->event.fde);
 455
 456         rc = tstream_bsd_existing_socket(dns_conn,
 457                         socket_get_fd(conn->socket),
 458                         &dns_conn->tstream);
 459         if (rc < 0) {
 460                 stream_terminate_connection(conn,
 461                                 "dns_tcp_accept: out of memory");
 462                 return;
 463         }
 464
 465         dns_conn->conn = conn;
 466         dns_conn->dns_socket = dns_socket;
 467         conn->private_data = dns_conn;
 468
 469         /*
 470          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 471          * packet_full_request_u16 provides the pdu length then.
 472          */
 473         subreq = tstream_read_pdu_blob_send(dns_conn,
 474                                             dns_conn->conn->event.ctx,
 475                                             dns_conn->tstream,
 476                                             2, /* initial_read_size */
 477                                             packet_full_request_u16,
 478                                             dns_conn);
 479         if (subreq == NULL) {
 480                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_accept: "
 481                                 "no memory for tstream_read_pdu_blob_send");
 482                 return;
 483         }
 484         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 485 }
 486
 487 static const struct stream_server_ops dns_tcp_stream_ops = {
 488         .name                   = "dns_tcp",
 489         .accept_connection      = dns_tcp_accept,
 490         .recv_handler           = dns_tcp_recv,
 491         .send_handler           = dns_tcp_send
 492 };
 493
 494 struct dns_udp_call {
 495         struct dns_udp_socket *sock;
 496         struct tsocket_address *src;
 497         DATA_BLOB in;
 498         DATA_BLOB out;
 499 };
 500
 501 static void dns_udp_call_process_done(struct tevent_req *subreq);
 502 static void dns_udp_call_sendto_done(struct tevent_req *subreq);
 503
 504 static void dns_udp_call_loop(struct tevent_req *subreq)
 505 {
 506         struct dns_udp_socket *sock = tevent_req_callback_data(subreq,
 507                                       struct dns_udp_socket);
 508         struct dns_server *dns = sock->dns_socket->dns;
 509         struct dns_udp_call *call;
 510         uint8_t *buf;
 511         ssize_t len;
 512         int sys_errno;
 513
 514         call = talloc(sock, struct dns_udp_call);
 515         if (call == NULL) {
 516                 talloc_free(call);
 517                 goto done;
 518         }
 519         call->sock = sock;
 520
 521         len = tdgram_recvfrom_recv(subreq, &sys_errno,
 522                                    call, &buf, &call->src);
 523         TALLOC_FREE(subreq);
 524         if (len == -1) {
 525                 talloc_free(call);
 526                 goto done;
 527         }
 528
 529         call->in.data = buf;
 530         call->in.length = len;
 531
 532         DEBUG(10,("Received DNS UDP packet of length %lu from %s\n",
 533                  (long)call->in.length,
 534                  tsocket_address_string(call->src, call)));
 535
 536         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 537                                   &call->in);
 538         if (subreq == NULL) {
 539                 TALLOC_FREE(call);
 540                 goto done;
 541         }
 542         tevent_req_set_callback(subreq, dns_udp_call_process_done, call);
 543
 544 done:
 545         subreq = tdgram_recvfrom_send(sock,
 546                                       sock->dns_socket->dns->task->event_ctx,
 547                                       sock->dgram);
 548         if (subreq == NULL) {
 549                 task_server_terminate(sock->dns_socket->dns->task,
 550                                       "no memory for tdgram_recvfrom_send",
 551                                       true);
 552                 return;
 553         }
 554         tevent_req_set_callback(subreq, dns_udp_call_loop, sock);
 555 }
 556
 557 static void dns_udp_call_process_done(struct tevent_req *subreq)
 558 {
 559         struct dns_udp_call *call = tevent_req_callback_data(
 560                 subreq, struct dns_udp_call);
 561         struct dns_udp_socket *sock = call->sock;
 562         struct dns_server *dns = sock->dns_socket->dns;
 563         WERROR err;
 564
 565         err = dns_process_recv(subreq, call, &call->out);
 566         TALLOC_FREE(subreq);
 567         if (!W_ERROR_IS_OK(err)) {
 568                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 569                 TALLOC_FREE(call);
 570                 return;
 571         }
 572
 573         subreq = tdgram_sendto_queue_send(call,
 574                                           dns->task->event_ctx,
 575                                           sock->dgram,
 576                                           sock->send_queue,
 577                                           call->out.data,
 578                                           call->out.length,
 579                                           call->src);
 580         if (subreq == NULL) {
 581                 talloc_free(call);
 582                 return;
 583         }
 584         tevent_req_set_callback(subreq, dns_udp_call_sendto_done, call);
 585
 586 }
 587 static void dns_udp_call_sendto_done(struct tevent_req *subreq)
 588 {
 589         struct dns_udp_call *call = tevent_req_callback_data(subreq,
 590                                        struct dns_udp_call);
 591         int sys_errno;
 592
 593         tdgram_sendto_queue_recv(subreq, &sys_errno);
 594
 595         /* We don't care about errors */
 596
 597         talloc_free(call);
 598 }
 599
 600 /*
 601   start listening on the given address
 602 */
 603 static NTSTATUS dns_add_socket(struct dns_server *dns,
 604                                const struct model_ops *model_ops,
 605                                const char *name,
 606                                const char *address,
 607                                uint16_t port)
 608 {
 609         struct dns_socket *dns_socket;
 610         struct dns_udp_socket *dns_udp_socket;
 611         struct tevent_req *udpsubreq;
 612         NTSTATUS status;
 613         int ret;
 614
 615         dns_socket = talloc(dns, struct dns_socket);
 616         NT_STATUS_HAVE_NO_MEMORY(dns_socket);
 617
 618         dns_socket->dns = dns;
 619
 620         ret = tsocket_address_inet_from_strings(dns_socket, "ip",
 621                                                 address, port,
 622                                                 &dns_socket->local_address);
 623         if (ret != 0) {
 624                 status = map_nt_error_from_unix_common(errno);
 625                 return status;
 626         }
 627
 628         status = stream_setup_socket(dns->task,
 629                                      dns->task->event_ctx,
 630                                      dns->task->lp_ctx,
 631                                      model_ops,
 632                                      &dns_tcp_stream_ops,
 633                                      "ip", address, &port,
 634                                      lpcfg_socket_options(dns->task->lp_ctx),
 635                                      dns_socket);
 636         if (!NT_STATUS_IS_OK(status)) {
 637                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 638                          address, port, nt_errstr(status)));
 639                 talloc_free(dns_socket);
 640                 return status;
 641         }
 642
 643         dns_udp_socket = talloc(dns_socket, struct dns_udp_socket);
 644         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket);
 645
 646         dns_udp_socket->dns_socket = dns_socket;
 647
 648         ret = tdgram_inet_udp_socket(dns_socket->local_address,
 649                                      NULL,
 650                                      dns_udp_socket,
 651                                      &dns_udp_socket->dgram);
 652         if (ret != 0) {
 653                 status = map_nt_error_from_unix_common(errno);
 654                 DEBUG(0,("Failed to bind to %s:%u UDP - %s\n",
 655                          address, port, nt_errstr(status)));
 656                 return status;
 657         }
 658
 659         dns_udp_socket->send_queue = tevent_queue_create(dns_udp_socket,
 660                                                          "dns_udp_send_queue");
 661         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket->send_queue);
 662
 663         udpsubreq = tdgram_recvfrom_send(dns_udp_socket,
 664                                          dns->task->event_ctx,
 665                                          dns_udp_socket->dgram);
 666         NT_STATUS_HAVE_NO_MEMORY(udpsubreq);
 667         tevent_req_set_callback(udpsubreq, dns_udp_call_loop, dns_udp_socket);
 668
 669         return NT_STATUS_OK;
 670 }
 671
 672 /*
 673   setup our listening sockets on the configured network interfaces
 674 */
 675 static NTSTATUS dns_startup_interfaces(struct dns_server *dns,
 676                                        struct interface *ifaces)
 677 {
 678         const struct model_ops *model_ops;
 679         int num_interfaces;
 680         TALLOC_CTX *tmp_ctx = talloc_new(dns);
 681         NTSTATUS status;
 682         int i;
 683
 684         /* within the dns task we want to be a single process, so
 685            ask for the single process model ops and pass these to the
 686            stream_setup_socket() call. */
 687         model_ops = process_model_startup("single");
 688         if (!model_ops) {
 689                 DEBUG(0,("Can't find 'single' process model_ops\n"));
 690                 return NT_STATUS_INTERNAL_ERROR;
 691         }
 692
 693         if (ifaces != NULL) {
 694                 num_interfaces = iface_list_count(ifaces);
 695
 696                 for (i=0; i<num_interfaces; i++) {
 697                         const char *address = talloc_strdup(tmp_ctx,
 698                                                             iface_list_n_ip(ifaces, i));
 699
 700                         status = dns_add_socket(dns, model_ops, "dns", address,
 701                                                 DNS_SERVICE_PORT);
 702                         NT_STATUS_NOT_OK_RETURN(status);
 703                 }
 704         } else {
 705                 int num_binds = 0;
 706                 char **wcard;
 707                 wcard = iface_list_wildcard(tmp_ctx);
 708                 if (wcard == NULL) {
 709                         DEBUG(0, ("No wildcard address available\n"));
 710                         return NT_STATUS_INTERNAL_ERROR;
 711                 }
 712                 for (i = 0; wcard[i] != NULL; i++) {
 713                         status = dns_add_socket(dns, model_ops, "dns", wcard[i],
 714                                                 DNS_SERVICE_PORT);
 715                         if (NT_STATUS_IS_OK(status)) {
 716                                 num_binds++;
 717                         }
 718                 }
 719                 if (num_binds == 0) {
 720                         talloc_free(tmp_ctx);
 721                         return NT_STATUS_INVALID_PARAMETER_MIX;
 722                 }
 723         }
 724
 725         talloc_free(tmp_ctx);
 726
 727         return NT_STATUS_OK;
 728 }
 729
 730 static struct dns_server_tkey_store *tkey_store_init(TALLOC_CTX *mem_ctx,
 731                                                      uint16_t size)
 732 {
 733         struct dns_server_tkey_store *buffer = talloc_zero(mem_ctx,
 734                                                 struct dns_server_tkey_store);
 735
 736         if (buffer == NULL) {
 737                 return NULL;
 738         }
 739
 740         buffer->size = size;
 741         buffer->next_idx = 0;
 742
 743         buffer->tkeys = talloc_zero_array(buffer, struct dns_server_tkey *, size);
 744         if (buffer->tkeys == NULL) {
 745                 TALLOC_FREE(buffer);
 746         }
 747
 748         return buffer;
 749 }
 750
 751 static NTSTATUS dns_server_reload_zones(struct dns_server *dns)
 752 {
 753         NTSTATUS status;
 754         struct dns_server_zone *new_list = NULL;
 755         struct dns_server_zone *old_list = NULL;
 756         struct dns_server_zone *old_zone;
 757         status = dns_common_zones(dns->samdb, dns, &new_list);
 758         if (!NT_STATUS_IS_OK(status)) {
 759                 return status;
 760         }
 761         dns->zones = new_list;
 762         while ((old_zone = DLIST_TAIL(old_list)) != NULL) {
 763                 DLIST_REMOVE(old_list, old_zone);
 764                 talloc_free(old_zone);
 765         }
 766
 767         return NT_STATUS_OK;
 768 }
 769
 770 /**
 771  * Called when the internal DNS server should reload the zones from DB, for
 772  * example, when zones are added or deleted through RPC or replicated by
 773  * inbound DRS.
 774  */
 775 static NTSTATUS dns_reload_zones(struct irpc_message *msg,
 776                                  struct dnssrv_reload_dns_zones *r)
 777 {
 778         struct dns_server *dns;
 779
 780         dns = talloc_get_type(msg->private_data, struct dns_server);
 781         if (dns == NULL) {
 782                 r->out.result = NT_STATUS_INTERNAL_ERROR;
 783                 return NT_STATUS_INTERNAL_ERROR;
 784         }
 785
 786         r->out.result = dns_server_reload_zones(dns);
 787
 788         return NT_STATUS_OK;
 789 }
 790
 791 static void dns_task_init(struct task_server *task)
 792 {
 793         struct dns_server *dns;
 794         NTSTATUS status;
 795         struct interface *ifaces = NULL;
 796         int ret;
 797         static const char * const attrs_none[] = { NULL};
 798         struct ldb_message *dns_acc;
 799         char *hostname_lower;
 800         char *dns_spn;
 801
 802         switch (lpcfg_server_role(task->lp_ctx)) {
 803         case ROLE_STANDALONE:
 804                 task_server_terminate(task, "dns: no DNS required in standalone configuration", false);
 805                 return;
 806         case ROLE_DOMAIN_MEMBER:
 807                 task_server_terminate(task, "dns: no DNS required in member server configuration", false);
 808                 return;
 809         case ROLE_ACTIVE_DIRECTORY_DC:
 810                 /* Yes, we want a DNS */
 811                 break;
 812         }
 813
 814         if (lpcfg_interfaces(task->lp_ctx) && lpcfg_bind_interfaces_only(task->lp_ctx)) {
 815                 load_interface_list(task, task->lp_ctx, &ifaces);
 816
 817                 if (iface_list_count(ifaces) == 0) {
 818                         task_server_terminate(task, "dns: no network interfaces configured", false);
 819                         return;
 820                 }
 821         }
 822
 823         task_server_set_title(task, "task[dns]");
 824
 825         dns = talloc_zero(task, struct dns_server);
 826         if (dns == NULL) {
 827                 task_server_terminate(task, "dns: out of memory", true);
 828                 return;
 829         }
 830
 831         dns->task = task;
 832         /*FIXME: Make this a configurable option */
 833         dns->max_payload = 4096;
 834
 835         dns->server_credentials = cli_credentials_init(dns);
 836         if (!dns->server_credentials) {
 837                 task_server_terminate(task, "Failed to init server credentials\n", true);
 838                 return;
 839         }
 840
 841         dns->samdb = samdb_connect(dns, dns->task->event_ctx, dns->task->lp_ctx,
 842                               system_session(dns->task->lp_ctx), 0);
 843         if (!dns->samdb) {
 844                 task_server_terminate(task, "dns: samdb_connect failed", true);
 845                 return;
 846         }
 847
 848         cli_credentials_set_conf(dns->server_credentials, task->lp_ctx);
 849
 850         hostname_lower = strlower_talloc(dns, lpcfg_netbios_name(task->lp_ctx));
 851         dns_spn = talloc_asprintf(dns, "DNS/%s.%s",
 852                                   hostname_lower,
 853                                   lpcfg_dnsdomain(task->lp_ctx));
 854         TALLOC_FREE(hostname_lower);
 855
 856         ret = dsdb_search_one(dns->samdb, dns, &dns_acc,
 857                               ldb_get_default_basedn(dns->samdb), LDB_SCOPE_SUBTREE,
 858                               attrs_none, 0, "(servicePrincipalName=%s)",
 859                               dns_spn);
 860         if (ret == LDB_SUCCESS) {
 861                 TALLOC_FREE(dns_acc);
 862                 if (!dns_spn) {
 863                         task_server_terminate(task, "dns: talloc_asprintf failed", true);
 864                         return;
 865                 }
 866                 status = cli_credentials_set_stored_principal(dns->server_credentials, task->lp_ctx, dns_spn);
 867                 if (!NT_STATUS_IS_OK(status)) {
 868                         task_server_terminate(task,
 869                                               talloc_asprintf(task, "Failed to obtain server credentials for DNS, "
 870                                                               "despite finding it in the samdb! %s\n",
 871                                                               nt_errstr(status)),
 872                                               true);
 873                         return;
 874                 }
 875         } else {
 876                 TALLOC_FREE(dns_spn);
 877                 status = cli_credentials_set_machine_account(dns->server_credentials, task->lp_ctx);
 878                 if (!NT_STATUS_IS_OK(status)) {
 879                         task_server_terminate(task,
 880                                               talloc_asprintf(task, "Failed to obtain server credentials, perhaps a standalone server?: %s\n",
 881                                                               nt_errstr(status)),
 882                                               true);
 883                         return;
 884                 }
 885         }
 886
 887         dns->tkeys = tkey_store_init(dns, TKEY_BUFFER_SIZE);
 888         if (!dns->tkeys) {
 889                 task_server_terminate(task, "Failed to allocate tkey storage\n", true);
 890                 return;
 891         }
 892
 893         status = dns_server_reload_zones(dns);
 894         if (!NT_STATUS_IS_OK(status)) {
 895                 task_server_terminate(task, "dns: failed to load DNS zones", true);
 896                 return;
 897         }
 898
 899         status = dns_startup_interfaces(dns, ifaces);
 900         if (!NT_STATUS_IS_OK(status)) {
 901                 task_server_terminate(task, "dns failed to setup interfaces", true);
 902                 return;
 903         }
 904
 905         /* Setup the IRPC interface and register handlers */
 906         status = irpc_add_name(task->msg_ctx, "dnssrv");
 907         if (!NT_STATUS_IS_OK(status)) {
 908                 task_server_terminate(task, "dns: failed to register IRPC name", true);
 909                 return;
 910         }
 911
 912         status = IRPC_REGISTER(task->msg_ctx, irpc, DNSSRV_RELOAD_DNS_ZONES,
 913                                dns_reload_zones, dns);
 914         if (!NT_STATUS_IS_OK(status)) {
 915                 task_server_terminate(task, "dns: failed to setup reload handler", true);
 916                 return;
 917         }
 918 }
 919
 920 NTSTATUS server_service_dns_init(void)
 921 {
 922         return register_server_service("dns", dns_task_init);
 923 }