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