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
  51 #undef DBGC_CLASS
  52 #define DBGC_CLASS DBGC_DNS
  53
  54 NTSTATUS server_service_dns_init(void);
  55
  56 /* hold information about one dns socket */
  57 struct dns_socket {
  58         struct dns_server *dns;
  59         struct tsocket_address *local_address;
  60 };
  61
  62 struct dns_udp_socket {
  63         struct dns_socket *dns_socket;
  64         struct tdgram_context *dgram;
  65         struct tevent_queue *send_queue;
  66 };
  67
  68 /*
  69   state of an open tcp connection
  70 */
  71 struct dns_tcp_connection {
  72         /* stream connection we belong to */
  73         struct stream_connection *conn;
  74
  75         /* the dns_server the connection belongs to */
  76         struct dns_socket *dns_socket;
  77
  78         struct tstream_context *tstream;
  79
  80         struct tevent_queue *send_queue;
  81 };
  82
  83 static void dns_tcp_terminate_connection(struct dns_tcp_connection *dnsconn, const char *reason)
  84 {
  85         stream_terminate_connection(dnsconn->conn, reason);
  86 }
  87
  88 static void dns_tcp_recv(struct stream_connection *conn, uint16_t flags)
  89 {
  90         struct dns_tcp_connection *dnsconn = talloc_get_type(conn->private_data,
  91                                                              struct dns_tcp_connection);
  92         /* this should never be triggered! */
  93         dns_tcp_terminate_connection(dnsconn, "dns_tcp_recv: called");
  94 }
  95
  96 static void dns_tcp_send(struct stream_connection *conn, uint16_t flags)
  97 {
  98         struct dns_tcp_connection *dnsconn = talloc_get_type(conn->private_data,
  99                                                              struct dns_tcp_connection);
 100         /* this should never be triggered! */
 101         dns_tcp_terminate_connection(dnsconn, "dns_tcp_send: called");
 102 }
 103
 104 struct dns_process_state {
 105         DATA_BLOB *in;
 106         struct dns_server *dns;
 107         struct dns_name_packet in_packet;
 108         struct dns_request_state state;
 109         uint16_t dns_err;
 110         struct dns_name_packet out_packet;
 111         DATA_BLOB out;
 112 };
 113
 114 static void dns_process_done(struct tevent_req *subreq);
 115
 116 static struct tevent_req *dns_process_send(TALLOC_CTX *mem_ctx,
 117                                            struct tevent_context *ev,
 118                                            struct dns_server *dns,
 119                                            DATA_BLOB *in)
 120 {
 121         struct tevent_req *req, *subreq;
 122         struct dns_process_state *state;
 123         enum ndr_err_code ndr_err;
 124         WERROR ret;
 125         const char *forwarder = lpcfg_dns_forwarder(dns->task->lp_ctx);
 126         req = tevent_req_create(mem_ctx, &state, struct dns_process_state);
 127         if (req == NULL) {
 128                 return NULL;
 129         }
 130         state->state.mem_ctx = state;
 131         state->in = in;
 132
 133         state->dns = dns;
 134
 135         if (in->length < 12) {
 136                 tevent_req_werror(req, WERR_INVALID_PARAM);
 137                 return tevent_req_post(req, ev);
 138         }
 139         dump_data_dbgc(DBGC_DNS, 8, in->data, in->length);
 140
 141         ndr_err = ndr_pull_struct_blob(
 142                 in, state, &state->in_packet,
 143                 (ndr_pull_flags_fn_t)ndr_pull_dns_name_packet);
 144
 145         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 146                 state->dns_err = DNS_RCODE_FORMERR;
 147                 tevent_req_done(req);
 148                 return tevent_req_post(req, ev);
 149         }
 150         if (DEBUGLVLC(DBGC_DNS, 8)) {
 151                 NDR_PRINT_DEBUGC(DBGC_DNS, dns_name_packet, &state->in_packet);
 152         }
 153
 154         ret = dns_verify_tsig(dns, state, &state->state, &state->in_packet, in);
 155         if (!W_ERROR_IS_OK(ret)) {
 156                 DEBUG(1, ("Failed to verify TSIG!\n"));
 157                 state->dns_err = werr_to_dns_err(ret);
 158                 tevent_req_done(req);
 159                 return tevent_req_post(req, ev);
 160         }
 161
 162         if (state->in_packet.operation & DNS_FLAG_REPLY) {
 163                 DEBUG(1, ("Won't reply to replies.\n"));
 164                 tevent_req_werror(req, WERR_INVALID_PARAM);
 165                 return tevent_req_post(req, ev);
 166         }
 167
 168         state->state.flags = state->in_packet.operation;
 169         state->state.flags |= DNS_FLAG_REPLY;
 170
 171
 172         if (forwarder && *forwarder) {
 173                 state->state.flags |= DNS_FLAG_RECURSION_AVAIL;
 174         }
 175
 176         state->out_packet = state->in_packet;
 177
 178         switch (state->in_packet.operation & DNS_OPCODE) {
 179         case DNS_OPCODE_QUERY:
 180                 subreq = dns_server_process_query_send(
 181                         state, ev, dns, &state->state, &state->in_packet);
 182                 if (tevent_req_nomem(subreq, req)) {
 183                         return tevent_req_post(req, ev);
 184                 }
 185                 tevent_req_set_callback(subreq, dns_process_done, req);
 186                 return req;
 187         case DNS_OPCODE_UPDATE:
 188                 ret = dns_server_process_update(
 189                         dns, &state->state, state, &state->in_packet,
 190                         &state->out_packet.answers, &state->out_packet.ancount,
 191                         &state->out_packet.nsrecs,  &state->out_packet.nscount,
 192                         &state->out_packet.additional,
 193                         &state->out_packet.arcount);
 194                 break;
 195         default:
 196                 ret = WERR_DNS_ERROR_RCODE_NOT_IMPLEMENTED;
 197         }
 198         if (!W_ERROR_IS_OK(ret)) {
 199                 state->dns_err = werr_to_dns_err(ret);
 200         }
 201         tevent_req_done(req);
 202         return tevent_req_post(req, ev);
 203 }
 204
 205 static void dns_process_done(struct tevent_req *subreq)
 206 {
 207         struct tevent_req *req = tevent_req_callback_data(
 208                 subreq, struct tevent_req);
 209         struct dns_process_state *state = tevent_req_data(
 210                 req, struct dns_process_state);
 211         WERROR ret;
 212
 213         ret = dns_server_process_query_recv(
 214                 subreq, state,
 215                 &state->out_packet.answers, &state->out_packet.ancount,
 216                 &state->out_packet.nsrecs,  &state->out_packet.nscount,
 217                 &state->out_packet.additional, &state->out_packet.arcount);
 218         TALLOC_FREE(subreq);
 219
 220         if (!W_ERROR_IS_OK(ret)) {
 221                 state->dns_err = werr_to_dns_err(ret);
 222         }
 223         tevent_req_done(req);
 224 }
 225
 226 static WERROR dns_process_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 227                                DATA_BLOB *out)
 228 {
 229         struct dns_process_state *state = tevent_req_data(
 230                 req, struct dns_process_state);
 231         enum ndr_err_code ndr_err;
 232         WERROR ret;
 233
 234         if (tevent_req_is_werror(req, &ret)) {
 235                 return ret;
 236         }
 237         if ((state->dns_err != DNS_RCODE_OK) &&
 238             (state->dns_err != DNS_RCODE_NXDOMAIN)) {
 239                 goto drop;
 240         }
 241         if (state->dns_err != DNS_RCODE_OK) {
 242                 state->out_packet.operation |= state->dns_err;
 243         }
 244         state->out_packet.operation |= state->state.flags;
 245
 246         if (state->state.sign) {
 247                 ret = dns_sign_tsig(state->dns, mem_ctx, &state->state,
 248                                     &state->out_packet, 0);
 249                 if (!W_ERROR_IS_OK(ret)) {
 250                         state->dns_err = DNS_RCODE_SERVFAIL;
 251                         goto drop;
 252                 }
 253         }
 254
 255         if (DEBUGLVLC(DBGC_DNS, 8)) {
 256                 NDR_PRINT_DEBUGC(DBGC_DNS, dns_name_packet, &state->out_packet);
 257         }
 258
 259         ndr_err = ndr_push_struct_blob(
 260                 out, mem_ctx, &state->out_packet,
 261                 (ndr_push_flags_fn_t)ndr_push_dns_name_packet);
 262         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 263                 DEBUG(1, ("Failed to push packet: %s!\n",
 264                           ndr_errstr(ndr_err)));
 265                 state->dns_err = DNS_RCODE_SERVFAIL;
 266                 goto drop;
 267         }
 268         return WERR_OK;
 269
 270 drop:
 271         *out = data_blob_talloc(mem_ctx, state->in->data, state->in->length);
 272         if (out->data == NULL) {
 273                 return WERR_NOMEM;
 274         }
 275         out->data[2] |= 0x80; /* Toggle DNS_FLAG_REPLY */
 276         out->data[3] |= state->dns_err;
 277         return WERR_OK;
 278 }
 279
 280 struct dns_tcp_call {
 281         struct dns_tcp_connection *dns_conn;
 282         DATA_BLOB in;
 283         DATA_BLOB out;
 284         uint8_t out_hdr[4];
 285         struct iovec out_iov[2];
 286 };
 287
 288 static void dns_tcp_call_process_done(struct tevent_req *subreq);
 289 static void dns_tcp_call_writev_done(struct tevent_req *subreq);
 290
 291 static void dns_tcp_call_loop(struct tevent_req *subreq)
 292 {
 293         struct dns_tcp_connection *dns_conn = tevent_req_callback_data(subreq,
 294                                       struct dns_tcp_connection);
 295         struct dns_server *dns = dns_conn->dns_socket->dns;
 296         struct dns_tcp_call *call;
 297         NTSTATUS status;
 298
 299         call = talloc(dns_conn, struct dns_tcp_call);
 300         if (call == NULL) {
 301                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 302                                 "no memory for dns_tcp_call");
 303                 return;
 304         }
 305         call->dns_conn = dns_conn;
 306
 307         status = tstream_read_pdu_blob_recv(subreq,
 308                                             call,
 309                                             &call->in);
 310         TALLOC_FREE(subreq);
 311         if (!NT_STATUS_IS_OK(status)) {
 312                 const char *reason;
 313
 314                 reason = talloc_asprintf(call, "dns_tcp_call_loop: "
 315                                          "tstream_read_pdu_blob_recv() - %s",
 316                                          nt_errstr(status));
 317                 if (!reason) {
 318                         reason = nt_errstr(status);
 319                 }
 320
 321                 dns_tcp_terminate_connection(dns_conn, reason);
 322                 return;
 323         }
 324
 325         DEBUG(10,("Received DNS TCP packet of length %lu from %s\n",
 326                  (long) call->in.length,
 327                  tsocket_address_string(dns_conn->conn->remote_address, call)));
 328
 329         /* skip length header */
 330         call->in.data += 2;
 331         call->in.length -= 2;
 332
 333         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 334                                   &call->in);
 335         if (subreq == NULL) {
 336                 dns_tcp_terminate_connection(
 337                         dns_conn, "dns_tcp_call_loop: dns_process_send "
 338                         "failed\n");
 339                 return;
 340         }
 341         tevent_req_set_callback(subreq, dns_tcp_call_process_done, call);
 342
 343         /*
 344          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 345          * packet_full_request_u16 provides the pdu length then.
 346          */
 347         subreq = tstream_read_pdu_blob_send(dns_conn,
 348                                             dns_conn->conn->event.ctx,
 349                                             dns_conn->tstream,
 350                                             2, /* initial_read_size */
 351                                             packet_full_request_u16,
 352                                             dns_conn);
 353         if (subreq == NULL) {
 354                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 355                                 "no memory for tstream_read_pdu_blob_send");
 356                 return;
 357         }
 358         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 359 }
 360
 361 static void dns_tcp_call_process_done(struct tevent_req *subreq)
 362 {
 363         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 364                         struct dns_tcp_call);
 365         struct dns_tcp_connection *dns_conn = call->dns_conn;
 366         WERROR err;
 367
 368         err = dns_process_recv(subreq, call, &call->out);
 369         TALLOC_FREE(subreq);
 370         if (!W_ERROR_IS_OK(err)) {
 371                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 372                 dns_tcp_terminate_connection(dns_conn,
 373                                 "dns_tcp_call_loop: process function failed");
 374                 return;
 375         }
 376
 377         /* First add the length of the out buffer */
 378         RSSVAL(call->out_hdr, 0, call->out.length);
 379         call->out_iov[0].iov_base = (char *) call->out_hdr;
 380         call->out_iov[0].iov_len = 2;
 381
 382         call->out_iov[1].iov_base = (char *) call->out.data;
 383         call->out_iov[1].iov_len = call->out.length;
 384
 385         subreq = tstream_writev_queue_send(call,
 386                                            dns_conn->conn->event.ctx,
 387                                            dns_conn->tstream,
 388                                            dns_conn->send_queue,
 389                                            call->out_iov, 2);
 390         if (subreq == NULL) {
 391                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 392                                 "no memory for tstream_writev_queue_send");
 393                 return;
 394         }
 395         tevent_req_set_callback(subreq, dns_tcp_call_writev_done, call);
 396 }
 397
 398 static void dns_tcp_call_writev_done(struct tevent_req *subreq)
 399 {
 400         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 401                         struct dns_tcp_call);
 402         int sys_errno;
 403         int rc;
 404
 405         rc = tstream_writev_queue_recv(subreq, &sys_errno);
 406         TALLOC_FREE(subreq);
 407         if (rc == -1) {
 408                 const char *reason;
 409
 410                 reason = talloc_asprintf(call, "dns_tcp_call_writev_done: "
 411                                          "tstream_writev_queue_recv() - %d:%s",
 412                                          sys_errno, strerror(sys_errno));
 413                 if (!reason) {
 414                         reason = "dns_tcp_call_writev_done: tstream_writev_queue_recv() failed";
 415                 }
 416
 417                 dns_tcp_terminate_connection(call->dns_conn, reason);
 418                 return;
 419         }
 420
 421         /* We don't care about errors */
 422
 423         talloc_free(call);
 424 }
 425
 426 /*
 427   called when we get a new connection
 428 */
 429 static void dns_tcp_accept(struct stream_connection *conn)
 430 {
 431         struct dns_socket *dns_socket;
 432         struct dns_tcp_connection *dns_conn;
 433         struct tevent_req *subreq;
 434         int rc;
 435
 436         dns_conn = talloc_zero(conn, struct dns_tcp_connection);
 437         if (dns_conn == NULL) {
 438                 stream_terminate_connection(conn,
 439                                 "dns_tcp_accept: out of memory");
 440                 return;
 441         }
 442
 443         dns_conn->send_queue = tevent_queue_create(conn, "dns_tcp_accept");
 444         if (dns_conn->send_queue == NULL) {
 445                 stream_terminate_connection(conn,
 446                                 "dns_tcp_accept: out of memory");
 447                 return;
 448         }
 449
 450         dns_socket = talloc_get_type(conn->private_data, struct dns_socket);
 451
 452         TALLOC_FREE(conn->event.fde);
 453
 454         rc = tstream_bsd_existing_socket(dns_conn,
 455                         socket_get_fd(conn->socket),
 456                         &dns_conn->tstream);
 457         if (rc < 0) {
 458                 stream_terminate_connection(conn,
 459                                 "dns_tcp_accept: out of memory");
 460                 return;
 461         }
 462
 463         dns_conn->conn = conn;
 464         dns_conn->dns_socket = dns_socket;
 465         conn->private_data = dns_conn;
 466
 467         /*
 468          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 469          * packet_full_request_u16 provides the pdu length then.
 470          */
 471         subreq = tstream_read_pdu_blob_send(dns_conn,
 472                                             dns_conn->conn->event.ctx,
 473                                             dns_conn->tstream,
 474                                             2, /* initial_read_size */
 475                                             packet_full_request_u16,
 476                                             dns_conn);
 477         if (subreq == NULL) {
 478                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_accept: "
 479                                 "no memory for tstream_read_pdu_blob_send");
 480                 return;
 481         }
 482         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 483 }
 484
 485 static const struct stream_server_ops dns_tcp_stream_ops = {
 486         .name                   = "dns_tcp",
 487         .accept_connection      = dns_tcp_accept,
 488         .recv_handler           = dns_tcp_recv,
 489         .send_handler           = dns_tcp_send
 490 };
 491
 492 struct dns_udp_call {
 493         struct dns_udp_socket *sock;
 494         struct tsocket_address *src;
 495         DATA_BLOB in;
 496         DATA_BLOB out;
 497 };
 498
 499 static void dns_udp_call_process_done(struct tevent_req *subreq);
 500 static void dns_udp_call_sendto_done(struct tevent_req *subreq);
 501
 502 static void dns_udp_call_loop(struct tevent_req *subreq)
 503 {
 504         struct dns_udp_socket *sock = tevent_req_callback_data(subreq,
 505                                       struct dns_udp_socket);
 506         struct dns_server *dns = sock->dns_socket->dns;
 507         struct dns_udp_call *call;
 508         uint8_t *buf;
 509         ssize_t len;
 510         int sys_errno;
 511
 512         call = talloc(sock, struct dns_udp_call);
 513         if (call == NULL) {
 514                 talloc_free(call);
 515                 goto done;
 516         }
 517         call->sock = sock;
 518
 519         len = tdgram_recvfrom_recv(subreq, &sys_errno,
 520                                    call, &buf, &call->src);
 521         TALLOC_FREE(subreq);
 522         if (len == -1) {
 523                 talloc_free(call);
 524                 goto done;
 525         }
 526
 527         call->in.data = buf;
 528         call->in.length = len;
 529
 530         DEBUG(10,("Received DNS UDP packet of length %lu from %s\n",
 531                  (long)call->in.length,
 532                  tsocket_address_string(call->src, call)));
 533
 534         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 535                                   &call->in);
 536         if (subreq == NULL) {
 537                 TALLOC_FREE(call);
 538                 goto done;
 539         }
 540         tevent_req_set_callback(subreq, dns_udp_call_process_done, call);
 541
 542 done:
 543         subreq = tdgram_recvfrom_send(sock,
 544                                       sock->dns_socket->dns->task->event_ctx,
 545                                       sock->dgram);
 546         if (subreq == NULL) {
 547                 task_server_terminate(sock->dns_socket->dns->task,
 548                                       "no memory for tdgram_recvfrom_send",
 549                                       true);
 550                 return;
 551         }
 552         tevent_req_set_callback(subreq, dns_udp_call_loop, sock);
 553 }
 554
 555 static void dns_udp_call_process_done(struct tevent_req *subreq)
 556 {
 557         struct dns_udp_call *call = tevent_req_callback_data(
 558                 subreq, struct dns_udp_call);
 559         struct dns_udp_socket *sock = call->sock;
 560         struct dns_server *dns = sock->dns_socket->dns;
 561         WERROR err;
 562
 563         err = dns_process_recv(subreq, call, &call->out);
 564         TALLOC_FREE(subreq);
 565         if (!W_ERROR_IS_OK(err)) {
 566                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 567                 TALLOC_FREE(call);
 568                 return;
 569         }
 570
 571         subreq = tdgram_sendto_queue_send(call,
 572                                           dns->task->event_ctx,
 573                                           sock->dgram,
 574                                           sock->send_queue,
 575                                           call->out.data,
 576                                           call->out.length,
 577                                           call->src);
 578         if (subreq == NULL) {
 579                 talloc_free(call);
 580                 return;
 581         }
 582         tevent_req_set_callback(subreq, dns_udp_call_sendto_done, call);
 583
 584 }
 585 static void dns_udp_call_sendto_done(struct tevent_req *subreq)
 586 {
 587         struct dns_udp_call *call = tevent_req_callback_data(subreq,
 588                                        struct dns_udp_call);
 589         int sys_errno;
 590
 591         tdgram_sendto_queue_recv(subreq, &sys_errno);
 592
 593         /* We don't care about errors */
 594
 595         talloc_free(call);
 596 }
 597
 598 /*
 599   start listening on the given address
 600 */
 601 static NTSTATUS dns_add_socket(struct dns_server *dns,
 602                                const struct model_ops *model_ops,
 603                                const char *name,
 604                                const char *address,
 605                                uint16_t port)
 606 {
 607         struct dns_socket *dns_socket;
 608         struct dns_udp_socket *dns_udp_socket;
 609         struct tevent_req *udpsubreq;
 610         NTSTATUS status;
 611         int ret;
 612
 613         dns_socket = talloc(dns, struct dns_socket);
 614         NT_STATUS_HAVE_NO_MEMORY(dns_socket);
 615
 616         dns_socket->dns = dns;
 617
 618         ret = tsocket_address_inet_from_strings(dns_socket, "ip",
 619                                                 address, port,
 620                                                 &dns_socket->local_address);
 621         if (ret != 0) {
 622                 status = map_nt_error_from_unix_common(errno);
 623                 return status;
 624         }
 625
 626         status = stream_setup_socket(dns->task,
 627                                      dns->task->event_ctx,
 628                                      dns->task->lp_ctx,
 629                                      model_ops,
 630                                      &dns_tcp_stream_ops,
 631                                      "ip", address, &port,
 632                                      lpcfg_socket_options(dns->task->lp_ctx),
 633                                      dns_socket);
 634         if (!NT_STATUS_IS_OK(status)) {
 635                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 636                          address, port, nt_errstr(status)));
 637                 talloc_free(dns_socket);
 638                 return status;
 639         }
 640
 641         dns_udp_socket = talloc(dns_socket, struct dns_udp_socket);
 642         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket);
 643
 644         dns_udp_socket->dns_socket = dns_socket;
 645
 646         ret = tdgram_inet_udp_socket(dns_socket->local_address,
 647                                      NULL,
 648                                      dns_udp_socket,
 649                                      &dns_udp_socket->dgram);
 650         if (ret != 0) {
 651                 status = map_nt_error_from_unix_common(errno);
 652                 DEBUG(0,("Failed to bind to %s:%u UDP - %s\n",
 653                          address, port, nt_errstr(status)));
 654                 return status;
 655         }
 656
 657         dns_udp_socket->send_queue = tevent_queue_create(dns_udp_socket,
 658                                                          "dns_udp_send_queue");
 659         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket->send_queue);
 660
 661         udpsubreq = tdgram_recvfrom_send(dns_udp_socket,
 662                                          dns->task->event_ctx,
 663                                          dns_udp_socket->dgram);
 664         NT_STATUS_HAVE_NO_MEMORY(udpsubreq);
 665         tevent_req_set_callback(udpsubreq, dns_udp_call_loop, dns_udp_socket);
 666
 667         return NT_STATUS_OK;
 668 }
 669
 670 /*
 671   setup our listening sockets on the configured network interfaces
 672 */
 673 static NTSTATUS dns_startup_interfaces(struct dns_server *dns,
 674                                        struct interface *ifaces)
 675 {
 676         const struct model_ops *model_ops;
 677         int num_interfaces;
 678         TALLOC_CTX *tmp_ctx = talloc_new(dns);
 679         NTSTATUS status;
 680         int i;
 681
 682         /* within the dns task we want to be a single process, so
 683            ask for the single process model ops and pass these to the
 684            stream_setup_socket() call. */
 685         model_ops = process_model_startup("single");
 686         if (!model_ops) {
 687                 DEBUG(0,("Can't find 'single' process model_ops\n"));
 688                 return NT_STATUS_INTERNAL_ERROR;
 689         }
 690
 691         if (ifaces != NULL) {
 692                 num_interfaces = iface_list_count(ifaces);
 693
 694                 for (i=0; i<num_interfaces; i++) {
 695                         const char *address = talloc_strdup(tmp_ctx,
 696                                                             iface_list_n_ip(ifaces, i));
 697
 698                         status = dns_add_socket(dns, model_ops, "dns", address,
 699                                                 DNS_SERVICE_PORT);
 700                         NT_STATUS_NOT_OK_RETURN(status);
 701                 }
 702         } else {
 703                 int num_binds = 0;
 704                 char **wcard;
 705                 wcard = iface_list_wildcard(tmp_ctx);
 706                 if (wcard == NULL) {
 707                         DEBUG(0, ("No wildcard address available\n"));
 708                         return NT_STATUS_INTERNAL_ERROR;
 709                 }
 710                 for (i = 0; wcard[i] != NULL; i++) {
 711                         status = dns_add_socket(dns, model_ops, "dns", wcard[i],
 712                                                 DNS_SERVICE_PORT);
 713                         if (NT_STATUS_IS_OK(status)) {
 714                                 num_binds++;
 715                         }
 716                 }
 717                 if (num_binds == 0) {
 718                         talloc_free(tmp_ctx);
 719                         return NT_STATUS_INVALID_PARAMETER_MIX;
 720                 }
 721         }
 722
 723         talloc_free(tmp_ctx);
 724
 725         return NT_STATUS_OK;
 726 }
 727
 728 static struct dns_server_tkey_store *tkey_store_init(TALLOC_CTX *mem_ctx,
 729                                                      uint16_t size)
 730 {
 731         struct dns_server_tkey_store *buffer = talloc_zero(mem_ctx,
 732                                                 struct dns_server_tkey_store);
 733
 734         if (buffer == NULL) {
 735                 return NULL;
 736         }
 737
 738         buffer->size = size;
 739         buffer->next_idx = 0;
 740
 741         buffer->tkeys = talloc_zero_array(buffer, struct dns_server_tkey *, size);
 742         if (buffer->tkeys == NULL) {
 743                 TALLOC_FREE(buffer);
 744         }
 745
 746         return buffer;
 747 }
 748
 749 static NTSTATUS dns_server_reload_zones(struct dns_server *dns)
 750 {
 751         NTSTATUS status;
 752         struct dns_server_zone *new_list = NULL;
 753         struct dns_server_zone *old_list = NULL;
 754         struct dns_server_zone *old_zone;
 755         status = dns_common_zones(dns->samdb, dns, &new_list);
 756         if (!NT_STATUS_IS_OK(status)) {
 757                 return status;
 758         }
 759         dns->zones = new_list;
 760         while ((old_zone = DLIST_TAIL(old_list)) != NULL) {
 761                 DLIST_REMOVE(old_list, old_zone);
 762                 talloc_free(old_zone);
 763         }
 764
 765         return NT_STATUS_OK;
 766 }
 767
 768 /**
 769  * Called when the internal DNS server should reload the zones from DB, for
 770  * example, when zones are added or deleted through RPC or replicated by
 771  * inbound DRS.
 772  */
 773 static NTSTATUS dns_reload_zones(struct irpc_message *msg,
 774                                  struct dnssrv_reload_dns_zones *r)
 775 {
 776         struct dns_server *dns;
 777
 778         dns = talloc_get_type(msg->private_data, struct dns_server);
 779         if (dns == NULL) {
 780                 r->out.result = NT_STATUS_INTERNAL_ERROR;
 781                 return NT_STATUS_INTERNAL_ERROR;
 782         }
 783
 784         r->out.result = dns_server_reload_zones(dns);
 785
 786         return NT_STATUS_OK;
 787 }
 788
 789 static void dns_task_init(struct task_server *task)
 790 {
 791         struct dns_server *dns;
 792         NTSTATUS status;
 793         struct interface *ifaces = NULL;
 794         int ret;
 795         static const char * const attrs_none[] = { NULL};
 796         struct ldb_message *dns_acc;
 797         char *hostname_lower;
 798         char *dns_spn;
 799
 800         switch (lpcfg_server_role(task->lp_ctx)) {
 801         case ROLE_STANDALONE:
 802                 task_server_terminate(task, "dns: no DNS required in standalone configuration", false);
 803                 return;
 804         case ROLE_DOMAIN_MEMBER:
 805                 task_server_terminate(task, "dns: no DNS required in member server configuration", false);
 806                 return;
 807         case ROLE_ACTIVE_DIRECTORY_DC:
 808                 /* Yes, we want a DNS */
 809                 break;
 810         }
 811
 812         if (lpcfg_interfaces(task->lp_ctx) && lpcfg_bind_interfaces_only(task->lp_ctx)) {
 813                 load_interface_list(task, task->lp_ctx, &ifaces);
 814
 815                 if (iface_list_count(ifaces) == 0) {
 816                         task_server_terminate(task, "dns: no network interfaces configured", false);
 817                         return;
 818                 }
 819         }
 820
 821         task_server_set_title(task, "task[dns]");
 822
 823         dns = talloc_zero(task, struct dns_server);
 824         if (dns == NULL) {
 825                 task_server_terminate(task, "dns: out of memory", true);
 826                 return;
 827         }
 828
 829         dns->task = task;
 830         /*FIXME: Make this a configurable option */
 831         dns->max_payload = 4096;
 832
 833         dns->server_credentials = cli_credentials_init(dns);
 834         if (!dns->server_credentials) {
 835                 task_server_terminate(task, "Failed to init server credentials\n", true);
 836                 return;
 837         }
 838
 839         dns->samdb = samdb_connect(dns, dns->task->event_ctx, dns->task->lp_ctx,
 840                               system_session(dns->task->lp_ctx), 0);
 841         if (!dns->samdb) {
 842                 task_server_terminate(task, "dns: samdb_connect failed", true);
 843                 return;
 844         }
 845
 846         cli_credentials_set_conf(dns->server_credentials, task->lp_ctx);
 847
 848         hostname_lower = strlower_talloc(dns, lpcfg_netbios_name(task->lp_ctx));
 849         dns_spn = talloc_asprintf(dns, "DNS/%s.%s",
 850                                   hostname_lower,
 851                                   lpcfg_dnsdomain(task->lp_ctx));
 852         TALLOC_FREE(hostname_lower);
 853
 854         ret = dsdb_search_one(dns->samdb, dns, &dns_acc,
 855                               ldb_get_default_basedn(dns->samdb), LDB_SCOPE_SUBTREE,
 856                               attrs_none, 0, "(servicePrincipalName=%s)",
 857                               dns_spn);
 858         if (ret == LDB_SUCCESS) {
 859                 TALLOC_FREE(dns_acc);
 860                 if (!dns_spn) {
 861                         task_server_terminate(task, "dns: talloc_asprintf failed", true);
 862                         return;
 863                 }
 864                 status = cli_credentials_set_stored_principal(dns->server_credentials, task->lp_ctx, dns_spn);
 865                 if (!NT_STATUS_IS_OK(status)) {
 866                         task_server_terminate(task,
 867                                               talloc_asprintf(task, "Failed to obtain server credentials for DNS, "
 868                                                               "despite finding it in the samdb! %s\n",
 869                                                               nt_errstr(status)),
 870                                               true);
 871                         return;
 872                 }
 873         } else {
 874                 TALLOC_FREE(dns_spn);
 875                 status = cli_credentials_set_machine_account(dns->server_credentials, task->lp_ctx);
 876                 if (!NT_STATUS_IS_OK(status)) {
 877                         task_server_terminate(task,
 878                                               talloc_asprintf(task, "Failed to obtain server credentials, perhaps a standalone server?: %s\n",
 879                                                               nt_errstr(status)),
 880                                               true);
 881                         return;
 882                 }
 883         }
 884
 885         dns->tkeys = tkey_store_init(dns, TKEY_BUFFER_SIZE);
 886         if (!dns->tkeys) {
 887                 task_server_terminate(task, "Failed to allocate tkey storage\n", true);
 888                 return;
 889         }
 890
 891         status = dns_server_reload_zones(dns);
 892         if (!NT_STATUS_IS_OK(status)) {
 893                 task_server_terminate(task, "dns: failed to load DNS zones", true);
 894                 return;
 895         }
 896
 897         status = dns_startup_interfaces(dns, ifaces);
 898         if (!NT_STATUS_IS_OK(status)) {
 899                 task_server_terminate(task, "dns failed to setup interfaces", true);
 900                 return;
 901         }
 902
 903         /* Setup the IRPC interface and register handlers */
 904         status = irpc_add_name(task->msg_ctx, "dnssrv");
 905         if (!NT_STATUS_IS_OK(status)) {
 906                 task_server_terminate(task, "dns: failed to register IRPC name", true);
 907                 return;
 908         }
 909
 910         status = IRPC_REGISTER(task->msg_ctx, irpc, DNSSRV_RELOAD_DNS_ZONES,
 911                                dns_reload_zones, dns);
 912         if (!NT_STATUS_IS_OK(status)) {
 913                 task_server_terminate(task, "dns: failed to setup reload handler", true);
 914                 return;
 915         }
 916 }
 917
 918 NTSTATUS server_service_dns_init(void)
 919 {
 920         return register_server_service("dns", dns_task_init);
 921 }