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