source4/dns_server/dns_server.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    DNS server startup
   5
   6    Copyright (C) 2010 Kai Blin  <kai@samba.org>
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "smbd/service_task.h"
  24 #include "smbd/service.h"
  25 #include "smbd/service_stream.h"
  26 #include "smbd/process_model.h"
  27 #include "lib/events/events.h"
  28 #include "lib/socket/socket.h"
  29 #include "lib/tsocket/tsocket.h"
  30 #include "libcli/util/tstream.h"
  31 #include "libcli/util/ntstatus.h"
  32 #include "system/network.h"
  33 #include "lib/stream/packet.h"
  34 #include "lib/socket/netif.h"
  35 #include "dns_server/dns_server.h"
  36 #include "param/param.h"
  37 #include "librpc/ndr/libndr.h"
  38 #include "librpc/gen_ndr/ndr_dns.h"
  39 #include "librpc/gen_ndr/ndr_dnsp.h"
  40 #include <ldb.h>
  41 #include "dsdb/samdb/samdb.h"
  42 #include "dsdb/common/util.h"
  43 #include "auth/session.h"
  44 #include "lib/util/dlinklist.h"
  45 #include "lib/util/tevent_werror.h"
  46 #include "auth/auth.h"
  47 #include "auth/credentials/credentials.h"
  48
  49 #undef DBGC_CLASS
  50 #define DBGC_CLASS DBGC_DNS
  51
  52 NTSTATUS server_service_dns_init(void);
  53
  54 /* hold information about one dns socket */
  55 struct dns_socket {
  56         struct dns_server *dns;
  57         struct tsocket_address *local_address;
  58 };
  59
  60 struct dns_udp_socket {
  61         struct dns_socket *dns_socket;
  62         struct tdgram_context *dgram;
  63         struct tevent_queue *send_queue;
  64 };
  65
  66 /*
  67   state of an open tcp connection
  68 */
  69 struct dns_tcp_connection {
  70         /* stream connection we belong to */
  71         struct stream_connection *conn;
  72
  73         /* the dns_server the connection belongs to */
  74         struct dns_socket *dns_socket;
  75
  76         struct tstream_context *tstream;
  77
  78         struct tevent_queue *send_queue;
  79 };
  80
  81 static void dns_tcp_terminate_connection(struct dns_tcp_connection *dnsconn, const char *reason)
  82 {
  83         stream_terminate_connection(dnsconn->conn, reason);
  84 }
  85
  86 static void dns_tcp_recv(struct stream_connection *conn, uint16_t flags)
  87 {
  88         struct dns_tcp_connection *dnsconn = talloc_get_type(conn->private_data,
  89                                                              struct dns_tcp_connection);
  90         /* this should never be triggered! */
  91         dns_tcp_terminate_connection(dnsconn, "dns_tcp_recv: called");
  92 }
  93
  94 static void dns_tcp_send(struct stream_connection *conn, uint16_t flags)
  95 {
  96         struct dns_tcp_connection *dnsconn = talloc_get_type(conn->private_data,
  97                                                              struct dns_tcp_connection);
  98         /* this should never be triggered! */
  99         dns_tcp_terminate_connection(dnsconn, "dns_tcp_send: called");
 100 }
 101
 102 struct dns_process_state {
 103         DATA_BLOB *in;
 104         struct dns_server *dns;
 105         struct dns_name_packet in_packet;
 106         struct dns_request_state state;
 107         uint16_t dns_err;
 108         struct dns_name_packet out_packet;
 109         DATA_BLOB out;
 110 };
 111
 112 static void dns_process_done(struct tevent_req *subreq);
 113
 114 static struct tevent_req *dns_process_send(TALLOC_CTX *mem_ctx,
 115                                            struct tevent_context *ev,
 116                                            struct dns_server *dns,
 117                                            DATA_BLOB *in)
 118 {
 119         struct tevent_req *req, *subreq;
 120         struct dns_process_state *state;
 121         enum ndr_err_code ndr_err;
 122         WERROR ret;
 123         const char *forwarder = lpcfg_dns_forwarder(dns->task->lp_ctx);
 124         req = tevent_req_create(mem_ctx, &state, struct dns_process_state);
 125         if (req == NULL) {
 126                 return NULL;
 127         }
 128         state->state.mem_ctx = state;
 129         state->in = in;
 130
 131         state->dns = dns;
 132
 133         if (in->length < 12) {
 134                 tevent_req_werror(req, WERR_INVALID_PARAM);
 135                 return tevent_req_post(req, ev);
 136         }
 137         dump_data_dbgc(DBGC_DNS, 8, in->data, in->length);
 138
 139         ndr_err = ndr_pull_struct_blob(
 140                 in, state, &state->in_packet,
 141                 (ndr_pull_flags_fn_t)ndr_pull_dns_name_packet);
 142
 143         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 144                 state->dns_err = DNS_RCODE_FORMERR;
 145                 tevent_req_done(req);
 146                 return tevent_req_post(req, ev);
 147         }
 148         if (DEBUGLVLC(DBGC_DNS, 8)) {
 149                 NDR_PRINT_DEBUGC(DBGC_DNS, dns_name_packet, &state->in_packet);
 150         }
 151
 152         ret = dns_verify_tsig(dns, state, &state->state, &state->in_packet, in);
 153         if (!W_ERROR_IS_OK(ret)) {
 154                 DEBUG(1, ("Failed to verify TSIG!\n"));
 155                 state->dns_err = werr_to_dns_err(ret);
 156                 tevent_req_done(req);
 157                 return tevent_req_post(req, ev);
 158         }
 159
 160         if (state->in_packet.operation & DNS_FLAG_REPLY) {
 161                 DEBUG(1, ("Won't reply to replies.\n"));
 162                 tevent_req_werror(req, WERR_INVALID_PARAM);
 163                 return tevent_req_post(req, ev);
 164         }
 165
 166         state->state.flags = state->in_packet.operation;
 167         state->state.flags |= DNS_FLAG_REPLY;
 168
 169
 170         if (forwarder && *forwarder) {
 171                 state->state.flags |= DNS_FLAG_RECURSION_AVAIL;
 172         }
 173
 174         state->out_packet = state->in_packet;
 175
 176         switch (state->in_packet.operation & DNS_OPCODE) {
 177         case DNS_OPCODE_QUERY:
 178                 subreq = dns_server_process_query_send(
 179                         state, ev, dns, &state->state, &state->in_packet);
 180                 if (tevent_req_nomem(subreq, req)) {
 181                         return tevent_req_post(req, ev);
 182                 }
 183                 tevent_req_set_callback(subreq, dns_process_done, req);
 184                 return req;
 185         case DNS_OPCODE_UPDATE:
 186                 ret = dns_server_process_update(
 187                         dns, &state->state, state, &state->in_packet,
 188                         &state->out_packet.answers, &state->out_packet.ancount,
 189                         &state->out_packet.nsrecs,  &state->out_packet.nscount,
 190                         &state->out_packet.additional,
 191                         &state->out_packet.arcount);
 192                 break;
 193         default:
 194                 ret = WERR_DNS_ERROR_RCODE_NOT_IMPLEMENTED;
 195         }
 196         if (!W_ERROR_IS_OK(ret)) {
 197                 state->dns_err = werr_to_dns_err(ret);
 198         }
 199         tevent_req_done(req);
 200         return tevent_req_post(req, ev);
 201 }
 202
 203 static void dns_process_done(struct tevent_req *subreq)
 204 {
 205         struct tevent_req *req = tevent_req_callback_data(
 206                 subreq, struct tevent_req);
 207         struct dns_process_state *state = tevent_req_data(
 208                 req, struct dns_process_state);
 209         WERROR ret;
 210
 211         ret = dns_server_process_query_recv(
 212                 subreq, state,
 213                 &state->out_packet.answers, &state->out_packet.ancount,
 214                 &state->out_packet.nsrecs,  &state->out_packet.nscount,
 215                 &state->out_packet.additional, &state->out_packet.arcount);
 216         TALLOC_FREE(subreq);
 217
 218         if (!W_ERROR_IS_OK(ret)) {
 219                 state->dns_err = werr_to_dns_err(ret);
 220         }
 221         tevent_req_done(req);
 222 }
 223
 224 static WERROR dns_process_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 225                                DATA_BLOB *out)
 226 {
 227         struct dns_process_state *state = tevent_req_data(
 228                 req, struct dns_process_state);
 229         enum ndr_err_code ndr_err;
 230         WERROR ret;
 231
 232         if (tevent_req_is_werror(req, &ret)) {
 233                 return ret;
 234         }
 235         if (state->dns_err != DNS_RCODE_OK) {
 236                 goto drop;
 237         }
 238         state->out_packet.operation |= state->state.flags;
 239
 240         if (state->state.sign) {
 241                 ret = dns_sign_tsig(state->dns, mem_ctx, &state->state,
 242                                     &state->out_packet, 0);
 243                 if (!W_ERROR_IS_OK(ret)) {
 244                         state->dns_err = DNS_RCODE_SERVFAIL;
 245                         goto drop;
 246                 }
 247         }
 248
 249         if (DEBUGLVLC(DBGC_DNS, 8)) {
 250                 NDR_PRINT_DEBUGC(DBGC_DNS, dns_name_packet, &state->out_packet);
 251         }
 252
 253         ndr_err = ndr_push_struct_blob(
 254                 out, mem_ctx, &state->out_packet,
 255                 (ndr_push_flags_fn_t)ndr_push_dns_name_packet);
 256         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 257                 DEBUG(1, ("Failed to push packet: %s!\n",
 258                           ndr_errstr(ndr_err)));
 259                 state->dns_err = DNS_RCODE_SERVFAIL;
 260                 goto drop;
 261         }
 262         return WERR_OK;
 263
 264 drop:
 265         *out = data_blob_talloc(mem_ctx, state->in->data, state->in->length);
 266         if (out->data == NULL) {
 267                 return WERR_NOMEM;
 268         }
 269         out->data[2] |= 0x80; /* Toggle DNS_FLAG_REPLY */
 270         out->data[3] |= state->dns_err;
 271         return WERR_OK;
 272 }
 273
 274 struct dns_tcp_call {
 275         struct dns_tcp_connection *dns_conn;
 276         DATA_BLOB in;
 277         DATA_BLOB out;
 278         uint8_t out_hdr[4];
 279         struct iovec out_iov[2];
 280 };
 281
 282 static void dns_tcp_call_process_done(struct tevent_req *subreq);
 283 static void dns_tcp_call_writev_done(struct tevent_req *subreq);
 284
 285 static void dns_tcp_call_loop(struct tevent_req *subreq)
 286 {
 287         struct dns_tcp_connection *dns_conn = tevent_req_callback_data(subreq,
 288                                       struct dns_tcp_connection);
 289         struct dns_server *dns = dns_conn->dns_socket->dns;
 290         struct dns_tcp_call *call;
 291         NTSTATUS status;
 292
 293         call = talloc(dns_conn, struct dns_tcp_call);
 294         if (call == NULL) {
 295                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 296                                 "no memory for dns_tcp_call");
 297                 return;
 298         }
 299         call->dns_conn = dns_conn;
 300
 301         status = tstream_read_pdu_blob_recv(subreq,
 302                                             call,
 303                                             &call->in);
 304         TALLOC_FREE(subreq);
 305         if (!NT_STATUS_IS_OK(status)) {
 306                 const char *reason;
 307
 308                 reason = talloc_asprintf(call, "dns_tcp_call_loop: "
 309                                          "tstream_read_pdu_blob_recv() - %s",
 310                                          nt_errstr(status));
 311                 if (!reason) {
 312                         reason = nt_errstr(status);
 313                 }
 314
 315                 dns_tcp_terminate_connection(dns_conn, reason);
 316                 return;
 317         }
 318
 319         DEBUG(10,("Received DNS TCP packet of length %lu from %s\n",
 320                  (long) call->in.length,
 321                  tsocket_address_string(dns_conn->conn->remote_address, call)));
 322
 323         /* skip length header */
 324         call->in.data += 2;
 325         call->in.length -= 2;
 326
 327         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 328                                   &call->in);
 329         if (subreq == NULL) {
 330                 dns_tcp_terminate_connection(
 331                         dns_conn, "dns_tcp_call_loop: dns_process_send "
 332                         "failed\n");
 333                 return;
 334         }
 335         tevent_req_set_callback(subreq, dns_tcp_call_process_done, call);
 336
 337         /*
 338          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 339          * packet_full_request_u16 provides the pdu length then.
 340          */
 341         subreq = tstream_read_pdu_blob_send(dns_conn,
 342                                             dns_conn->conn->event.ctx,
 343                                             dns_conn->tstream,
 344                                             2, /* initial_read_size */
 345                                             packet_full_request_u16,
 346                                             dns_conn);
 347         if (subreq == NULL) {
 348                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 349                                 "no memory for tstream_read_pdu_blob_send");
 350                 return;
 351         }
 352         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 353 }
 354
 355 static void dns_tcp_call_process_done(struct tevent_req *subreq)
 356 {
 357         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 358                         struct dns_tcp_call);
 359         struct dns_tcp_connection *dns_conn = call->dns_conn;
 360         WERROR err;
 361
 362         err = dns_process_recv(subreq, call, &call->out);
 363         TALLOC_FREE(subreq);
 364         if (!W_ERROR_IS_OK(err)) {
 365                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 366                 dns_tcp_terminate_connection(dns_conn,
 367                                 "dns_tcp_call_loop: process function failed");
 368                 return;
 369         }
 370
 371         /* First add the length of the out buffer */
 372         RSSVAL(call->out_hdr, 0, call->out.length);
 373         call->out_iov[0].iov_base = (char *) call->out_hdr;
 374         call->out_iov[0].iov_len = 2;
 375
 376         call->out_iov[1].iov_base = (char *) call->out.data;
 377         call->out_iov[1].iov_len = call->out.length;
 378
 379         subreq = tstream_writev_queue_send(call,
 380                                            dns_conn->conn->event.ctx,
 381                                            dns_conn->tstream,
 382                                            dns_conn->send_queue,
 383                                            call->out_iov, 2);
 384         if (subreq == NULL) {
 385                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 386                                 "no memory for tstream_writev_queue_send");
 387                 return;
 388         }
 389         tevent_req_set_callback(subreq, dns_tcp_call_writev_done, call);
 390 }
 391
 392 static void dns_tcp_call_writev_done(struct tevent_req *subreq)
 393 {
 394         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 395                         struct dns_tcp_call);
 396         int sys_errno;
 397         int rc;
 398
 399         rc = tstream_writev_queue_recv(subreq, &sys_errno);
 400         TALLOC_FREE(subreq);
 401         if (rc == -1) {
 402                 const char *reason;
 403
 404                 reason = talloc_asprintf(call, "dns_tcp_call_writev_done: "
 405                                          "tstream_writev_queue_recv() - %d:%s",
 406                                          sys_errno, strerror(sys_errno));
 407                 if (!reason) {
 408                         reason = "dns_tcp_call_writev_done: tstream_writev_queue_recv() failed";
 409                 }
 410
 411                 dns_tcp_terminate_connection(call->dns_conn, reason);
 412                 return;
 413         }
 414
 415         /* We don't care about errors */
 416
 417         talloc_free(call);
 418 }
 419
 420 /*
 421   called when we get a new connection
 422 */
 423 static void dns_tcp_accept(struct stream_connection *conn)
 424 {
 425         struct dns_socket *dns_socket;
 426         struct dns_tcp_connection *dns_conn;
 427         struct tevent_req *subreq;
 428         int rc;
 429
 430         dns_conn = talloc_zero(conn, struct dns_tcp_connection);
 431         if (dns_conn == NULL) {
 432                 stream_terminate_connection(conn,
 433                                 "dns_tcp_accept: out of memory");
 434                 return;
 435         }
 436
 437         dns_conn->send_queue = tevent_queue_create(conn, "dns_tcp_accept");
 438         if (dns_conn->send_queue == NULL) {
 439                 stream_terminate_connection(conn,
 440                                 "dns_tcp_accept: out of memory");
 441                 return;
 442         }
 443
 444         dns_socket = talloc_get_type(conn->private_data, struct dns_socket);
 445
 446         TALLOC_FREE(conn->event.fde);
 447
 448         rc = tstream_bsd_existing_socket(dns_conn,
 449                         socket_get_fd(conn->socket),
 450                         &dns_conn->tstream);
 451         if (rc < 0) {
 452                 stream_terminate_connection(conn,
 453                                 "dns_tcp_accept: out of memory");
 454                 return;
 455         }
 456
 457         dns_conn->conn = conn;
 458         dns_conn->dns_socket = dns_socket;
 459         conn->private_data = dns_conn;
 460
 461         /*
 462          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 463          * packet_full_request_u16 provides the pdu length then.
 464          */
 465         subreq = tstream_read_pdu_blob_send(dns_conn,
 466                                             dns_conn->conn->event.ctx,
 467                                             dns_conn->tstream,
 468                                             2, /* initial_read_size */
 469                                             packet_full_request_u16,
 470                                             dns_conn);
 471         if (subreq == NULL) {
 472                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_accept: "
 473                                 "no memory for tstream_read_pdu_blob_send");
 474                 return;
 475         }
 476         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 477 }
 478
 479 static const struct stream_server_ops dns_tcp_stream_ops = {
 480         .name                   = "dns_tcp",
 481         .accept_connection      = dns_tcp_accept,
 482         .recv_handler           = dns_tcp_recv,
 483         .send_handler           = dns_tcp_send
 484 };
 485
 486 struct dns_udp_call {
 487         struct dns_udp_socket *sock;
 488         struct tsocket_address *src;
 489         DATA_BLOB in;
 490         DATA_BLOB out;
 491 };
 492
 493 static void dns_udp_call_process_done(struct tevent_req *subreq);
 494 static void dns_udp_call_sendto_done(struct tevent_req *subreq);
 495
 496 static void dns_udp_call_loop(struct tevent_req *subreq)
 497 {
 498         struct dns_udp_socket *sock = tevent_req_callback_data(subreq,
 499                                       struct dns_udp_socket);
 500         struct dns_server *dns = sock->dns_socket->dns;
 501         struct dns_udp_call *call;
 502         uint8_t *buf;
 503         ssize_t len;
 504         int sys_errno;
 505
 506         call = talloc(sock, struct dns_udp_call);
 507         if (call == NULL) {
 508                 talloc_free(call);
 509                 goto done;
 510         }
 511         call->sock = sock;
 512
 513         len = tdgram_recvfrom_recv(subreq, &sys_errno,
 514                                    call, &buf, &call->src);
 515         TALLOC_FREE(subreq);
 516         if (len == -1) {
 517                 talloc_free(call);
 518                 goto done;
 519         }
 520
 521         call->in.data = buf;
 522         call->in.length = len;
 523
 524         DEBUG(10,("Received DNS UDP packet of length %lu from %s\n",
 525                  (long)call->in.length,
 526                  tsocket_address_string(call->src, call)));
 527
 528         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 529                                   &call->in);
 530         if (subreq == NULL) {
 531                 TALLOC_FREE(call);
 532                 goto done;
 533         }
 534         tevent_req_set_callback(subreq, dns_udp_call_process_done, call);
 535
 536 done:
 537         subreq = tdgram_recvfrom_send(sock,
 538                                       sock->dns_socket->dns->task->event_ctx,
 539                                       sock->dgram);
 540         if (subreq == NULL) {
 541                 task_server_terminate(sock->dns_socket->dns->task,
 542                                       "no memory for tdgram_recvfrom_send",
 543                                       true);
 544                 return;
 545         }
 546         tevent_req_set_callback(subreq, dns_udp_call_loop, sock);
 547 }
 548
 549 static void dns_udp_call_process_done(struct tevent_req *subreq)
 550 {
 551         struct dns_udp_call *call = tevent_req_callback_data(
 552                 subreq, struct dns_udp_call);
 553         struct dns_udp_socket *sock = call->sock;
 554         struct dns_server *dns = sock->dns_socket->dns;
 555         WERROR err;
 556
 557         err = dns_process_recv(subreq, call, &call->out);
 558         TALLOC_FREE(subreq);
 559         if (!W_ERROR_IS_OK(err)) {
 560                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 561                 TALLOC_FREE(call);
 562                 return;
 563         }
 564
 565         subreq = tdgram_sendto_queue_send(call,
 566                                           dns->task->event_ctx,
 567                                           sock->dgram,
 568                                           sock->send_queue,
 569                                           call->out.data,
 570                                           call->out.length,
 571                                           call->src);
 572         if (subreq == NULL) {
 573                 talloc_free(call);
 574                 return;
 575         }
 576         tevent_req_set_callback(subreq, dns_udp_call_sendto_done, call);
 577
 578 }
 579 static void dns_udp_call_sendto_done(struct tevent_req *subreq)
 580 {
 581         struct dns_udp_call *call = tevent_req_callback_data(subreq,
 582                                        struct dns_udp_call);
 583         int sys_errno;
 584
 585         tdgram_sendto_queue_recv(subreq, &sys_errno);
 586
 587         /* We don't care about errors */
 588
 589         talloc_free(call);
 590 }
 591
 592 /*
 593   start listening on the given address
 594 */
 595 static NTSTATUS dns_add_socket(struct dns_server *dns,
 596                                const struct model_ops *model_ops,
 597                                const char *name,
 598                                const char *address,
 599                                uint16_t port)
 600 {
 601         struct dns_socket *dns_socket;
 602         struct dns_udp_socket *dns_udp_socket;
 603         struct tevent_req *udpsubreq;
 604         NTSTATUS status;
 605         int ret;
 606
 607         dns_socket = talloc(dns, struct dns_socket);
 608         NT_STATUS_HAVE_NO_MEMORY(dns_socket);
 609
 610         dns_socket->dns = dns;
 611
 612         ret = tsocket_address_inet_from_strings(dns_socket, "ip",
 613                                                 address, port,
 614                                                 &dns_socket->local_address);
 615         if (ret != 0) {
 616                 status = map_nt_error_from_unix_common(errno);
 617                 return status;
 618         }
 619
 620         status = stream_setup_socket(dns->task,
 621                                      dns->task->event_ctx,
 622                                      dns->task->lp_ctx,
 623                                      model_ops,
 624                                      &dns_tcp_stream_ops,
 625                                      "ip", address, &port,
 626                                      lpcfg_socket_options(dns->task->lp_ctx),
 627                                      dns_socket);
 628         if (!NT_STATUS_IS_OK(status)) {
 629                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 630                          address, port, nt_errstr(status)));
 631                 talloc_free(dns_socket);
 632                 return status;
 633         }
 634
 635         dns_udp_socket = talloc(dns_socket, struct dns_udp_socket);
 636         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket);
 637
 638         dns_udp_socket->dns_socket = dns_socket;
 639
 640         ret = tdgram_inet_udp_socket(dns_socket->local_address,
 641                                      NULL,
 642                                      dns_udp_socket,
 643                                      &dns_udp_socket->dgram);
 644         if (ret != 0) {
 645                 status = map_nt_error_from_unix_common(errno);
 646                 DEBUG(0,("Failed to bind to %s:%u UDP - %s\n",
 647                          address, port, nt_errstr(status)));
 648                 return status;
 649         }
 650
 651         dns_udp_socket->send_queue = tevent_queue_create(dns_udp_socket,
 652                                                          "dns_udp_send_queue");
 653         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket->send_queue);
 654
 655         udpsubreq = tdgram_recvfrom_send(dns_udp_socket,
 656                                          dns->task->event_ctx,
 657                                          dns_udp_socket->dgram);
 658         NT_STATUS_HAVE_NO_MEMORY(udpsubreq);
 659         tevent_req_set_callback(udpsubreq, dns_udp_call_loop, dns_udp_socket);
 660
 661         return NT_STATUS_OK;
 662 }
 663
 664 /*
 665   setup our listening sockets on the configured network interfaces
 666 */
 667 static NTSTATUS dns_startup_interfaces(struct dns_server *dns,
 668                                        struct interface *ifaces)
 669 {
 670         const struct model_ops *model_ops;
 671         int num_interfaces;
 672         TALLOC_CTX *tmp_ctx = talloc_new(dns);
 673         NTSTATUS status;
 674         int i;
 675
 676         /* within the dns task we want to be a single process, so
 677            ask for the single process model ops and pass these to the
 678            stream_setup_socket() call. */
 679         model_ops = process_model_startup("single");
 680         if (!model_ops) {
 681                 DEBUG(0,("Can't find 'single' process model_ops\n"));
 682                 return NT_STATUS_INTERNAL_ERROR;
 683         }
 684
 685         if (ifaces != NULL) {
 686                 num_interfaces = iface_list_count(ifaces);
 687
 688                 for (i=0; i<num_interfaces; i++) {
 689                         const char *address = talloc_strdup(tmp_ctx,
 690                                                             iface_list_n_ip(ifaces, i));
 691
 692                         status = dns_add_socket(dns, model_ops, "dns", address,
 693                                                 DNS_SERVICE_PORT);
 694                         NT_STATUS_NOT_OK_RETURN(status);
 695                 }
 696         } else {
 697                 int num_binds = 0;
 698                 char **wcard;
 699                 wcard = iface_list_wildcard(tmp_ctx);
 700                 if (wcard == NULL) {
 701                         DEBUG(0, ("No wildcard address available\n"));
 702                         return NT_STATUS_INTERNAL_ERROR;
 703                 }
 704                 for (i = 0; wcard[i] != NULL; i++) {
 705                         status = dns_add_socket(dns, model_ops, "dns", wcard[i],
 706                                                 DNS_SERVICE_PORT);
 707                         if (NT_STATUS_IS_OK(status)) {
 708                                 num_binds++;
 709                         }
 710                 }
 711                 if (num_binds == 0) {
 712                         talloc_free(tmp_ctx);
 713                         return NT_STATUS_INVALID_PARAMETER_MIX;
 714                 }
 715         }
 716
 717         talloc_free(tmp_ctx);
 718
 719         return NT_STATUS_OK;
 720 }
 721
 722 static int dns_server_sort_zones(struct ldb_message **m1, struct ldb_message **m2)
 723 {
 724         const char *n1, *n2;
 725         size_t l1, l2;
 726
 727         n1 = ldb_msg_find_attr_as_string(*m1, "name", NULL);
 728         n2 = ldb_msg_find_attr_as_string(*m2, "name", NULL);
 729
 730         l1 = strlen(n1);
 731         l2 = strlen(n2);
 732
 733         /* If the string lengths are not equal just sort by length */
 734         if (l1 != l2) {
 735                 /* If m1 is the larger zone name, return it first */
 736                 return l2 - l1;
 737         }
 738
 739         /*TODO: We need to compare DNs here, we want the DomainDNSZones first */
 740         return 0;
 741 }
 742
 743 static struct dns_server_tkey_store *tkey_store_init(TALLOC_CTX *mem_ctx,
 744                                                      uint16_t size)
 745 {
 746         struct dns_server_tkey_store *buffer = talloc_zero(mem_ctx,
 747                                                 struct dns_server_tkey_store);
 748
 749         if (buffer == NULL) {
 750                 return NULL;
 751         }
 752
 753         buffer->size = size;
 754         buffer->next_idx = 0;
 755
 756         buffer->tkeys = talloc_zero_array(buffer, struct dns_server_tkey *, size);
 757         if (buffer->tkeys == NULL) {
 758                 TALLOC_FREE(buffer);
 759         }
 760
 761         return buffer;
 762 }
 763
 764 static void dns_task_init(struct task_server *task)
 765 {
 766         struct dns_server *dns;
 767         NTSTATUS status;
 768         struct interface *ifaces = NULL;
 769         int ret;
 770         struct ldb_result *res;
 771         static const char * const attrs[] = { "name", NULL};
 772         static const char * const attrs_none[] = { NULL};
 773         unsigned int i;
 774         struct ldb_message *dns_acc;
 775         char *hostname_lower;
 776         char *dns_spn;
 777
 778         switch (lpcfg_server_role(task->lp_ctx)) {
 779         case ROLE_STANDALONE:
 780                 task_server_terminate(task, "dns: no DNS required in standalone configuration", false);
 781                 return;
 782         case ROLE_DOMAIN_MEMBER:
 783                 task_server_terminate(task, "dns: no DNS required in member server configuration", false);
 784                 return;
 785         case ROLE_ACTIVE_DIRECTORY_DC:
 786                 /* Yes, we want a DNS */
 787                 break;
 788         }
 789
 790         if (lpcfg_interfaces(task->lp_ctx) && lpcfg_bind_interfaces_only(task->lp_ctx)) {
 791                 load_interface_list(task, task->lp_ctx, &ifaces);
 792
 793                 if (iface_list_count(ifaces) == 0) {
 794                         task_server_terminate(task, "dns: no network interfaces configured", false);
 795                         return;
 796                 }
 797         }
 798
 799         task_server_set_title(task, "task[dns]");
 800
 801         dns = talloc_zero(task, struct dns_server);
 802         if (dns == NULL) {
 803                 task_server_terminate(task, "dns: out of memory", true);
 804                 return;
 805         }
 806
 807         dns->task = task;
 808         /*FIXME: Make this a configurable option */
 809         dns->max_payload = 4096;
 810
 811         dns->server_credentials = cli_credentials_init(dns);
 812         if (!dns->server_credentials) {
 813                 task_server_terminate(task, "Failed to init server credentials\n", true);
 814                 return;
 815         }
 816
 817         dns->samdb = samdb_connect(dns, dns->task->event_ctx, dns->task->lp_ctx,
 818                               system_session(dns->task->lp_ctx), 0);
 819         if (!dns->samdb) {
 820                 task_server_terminate(task, "dns: samdb_connect failed", true);
 821                 return;
 822         }
 823
 824         cli_credentials_set_conf(dns->server_credentials, task->lp_ctx);
 825
 826         hostname_lower = strlower_talloc(dns, lpcfg_netbios_name(task->lp_ctx));
 827         dns_spn = talloc_asprintf(dns, "DNS/%s.%s",
 828                                   hostname_lower,
 829                                   lpcfg_dnsdomain(task->lp_ctx));
 830         TALLOC_FREE(hostname_lower);
 831
 832         ret = dsdb_search_one(dns->samdb, dns, &dns_acc,
 833                               ldb_get_default_basedn(dns->samdb), LDB_SCOPE_SUBTREE,
 834                               attrs_none, 0, "(servicePrincipalName=%s)",
 835                               dns_spn);
 836         if (ret == LDB_SUCCESS) {
 837                 TALLOC_FREE(dns_acc);
 838                 if (!dns_spn) {
 839                         task_server_terminate(task, "dns: talloc_asprintf failed", true);
 840                         return;
 841                 }
 842                 status = cli_credentials_set_stored_principal(dns->server_credentials, task->lp_ctx, dns_spn);
 843                 if (!NT_STATUS_IS_OK(status)) {
 844                         task_server_terminate(task,
 845                                               talloc_asprintf(task, "Failed to obtain server credentials for DNS, "
 846                                                               "despite finding it in the samdb! %s\n",
 847                                                               nt_errstr(status)),
 848                                               true);
 849                         return;
 850                 }
 851         } else {
 852                 TALLOC_FREE(dns_spn);
 853                 status = cli_credentials_set_machine_account(dns->server_credentials, task->lp_ctx);
 854                 if (!NT_STATUS_IS_OK(status)) {
 855                         task_server_terminate(task,
 856                                               talloc_asprintf(task, "Failed to obtain server credentials, perhaps a standalone server?: %s\n",
 857                                                               nt_errstr(status)),
 858                                               true);
 859                         return;
 860                 }
 861         }
 862
 863         dns->tkeys = tkey_store_init(dns, TKEY_BUFFER_SIZE);
 864         if (!dns->tkeys) {
 865                 task_server_terminate(task, "Failed to allocate tkey storage\n", true);
 866                 return;
 867         }
 868
 869         // TODO: this search does not work against windows
 870         ret = dsdb_search(dns->samdb, dns, &res, NULL, LDB_SCOPE_SUBTREE,
 871                           attrs, DSDB_SEARCH_SEARCH_ALL_PARTITIONS, "(objectClass=dnsZone)");
 872         if (ret != LDB_SUCCESS) {
 873                 task_server_terminate(task,
 874                                       "dns: failed to look up root DNS zones",
 875                                       true);
 876                 return;
 877         }
 878
 879         TYPESAFE_QSORT(res->msgs, res->count, dns_server_sort_zones);
 880
 881         for (i=0; i < res->count; i++) {
 882                 struct dns_server_zone *z;
 883
 884                 z = talloc_zero(dns, struct dns_server_zone);
 885                 if (z == NULL) {
 886                         task_server_terminate(task, "dns failed to allocate memory", true);
 887                 }
 888
 889                 z->name = ldb_msg_find_attr_as_string(res->msgs[i], "name", NULL);
 890                 z->dn = talloc_move(z, &res->msgs[i]->dn);
 891                 /*
 892                  * Ignore the RootDNSServers zone and zones that we don't support yet
 893                  * RootDNSServers should never be returned (Windows DNS server don't)
 894                  * ..TrustAnchors should never be returned as is, (Windows returns
 895                  * TrustAnchors) and for the moment we don't support DNSSEC so we'd better
 896                  * not return this zone.
 897                  */
 898                 if ((strcmp(z->name, "RootDNSServers") == 0) ||
 899                     (strcmp(z->name, "..TrustAnchors") == 0))
 900                 {
 901                         DEBUG(10, ("Ignoring zone %s\n", z->name));
 902                         talloc_free(z);
 903                         continue;
 904                 }
 905                 DLIST_ADD_END(dns->zones, z, NULL);
 906         }
 907
 908         status = dns_startup_interfaces(dns, ifaces);
 909         if (!NT_STATUS_IS_OK(status)) {
 910                 task_server_terminate(task, "dns failed to setup interfaces", true);
 911                 return;
 912         }
 913 }
 914
 915 NTSTATUS server_service_dns_init(void)
 916 {
 917         return register_server_service("dns", dns_task_init);
 918 }