source4/dns_server/dns_server.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    DNS server startup
   5
   6    Copyright (C) 2010 Kai Blin  <kai@samba.org>
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "smbd/service_task.h"
  24 #include "smbd/service.h"
  25 #include "smbd/service_stream.h"
  26 #include "smbd/process_model.h"
  27 #include "lib/events/events.h"
  28 #include "lib/socket/socket.h"
  29 #include "lib/tsocket/tsocket.h"
  30 #include "libcli/util/tstream.h"
  31 #include "libcli/util/ntstatus.h"
  32 #include "system/network.h"
  33 #include "lib/stream/packet.h"
  34 #include "lib/socket/netif.h"
  35 #include "dns_server/dns_server.h"
  36 #include "param/param.h"
  37 #include "librpc/ndr/libndr.h"
  38 #include "librpc/gen_ndr/ndr_dns.h"
  39 #include "librpc/gen_ndr/ndr_dnsp.h"
  40 #include <ldb.h>
  41 #include "dsdb/samdb/samdb.h"
  42 #include "dsdb/common/util.h"
  43 #include "auth/session.h"
  44 #include "lib/util/dlinklist.h"
  45 #include "lib/util/tevent_werror.h"
  46 #include "auth/auth.h"
  47 #include "auth/credentials/credentials.h"
  48 #include "librpc/gen_ndr/ndr_irpc.h"
  49 #include "lib/messaging/irpc.h"
  50 #include "libds/common/roles.h"
  51
  52 #undef DBGC_CLASS
  53 #define DBGC_CLASS DBGC_DNS
  54
  55 NTSTATUS server_service_dns_init(TALLOC_CTX *);
  56
  57 /* hold information about one dns socket */
  58 struct dns_socket {
  59         struct dns_server *dns;
  60         struct tsocket_address *local_address;
  61 };
  62
  63 struct dns_udp_socket {
  64         struct dns_socket *dns_socket;
  65         struct tdgram_context *dgram;
  66         struct tevent_queue *send_queue;
  67 };
  68
  69 /*
  70   state of an open tcp connection
  71 */
  72 struct dns_tcp_connection {
  73         /* stream connection we belong to */
  74         struct stream_connection *conn;
  75
  76         /* the dns_server the connection belongs to */
  77         struct dns_socket *dns_socket;
  78
  79         struct tstream_context *tstream;
  80
  81         struct tevent_queue *send_queue;
  82 };
  83
  84 static void dns_tcp_terminate_connection(struct dns_tcp_connection *dnsconn, const char *reason)
  85 {
  86         stream_terminate_connection(dnsconn->conn, reason);
  87 }
  88
  89 static void dns_tcp_recv(struct stream_connection *conn, uint16_t flags)
  90 {
  91         struct dns_tcp_connection *dnsconn = talloc_get_type(conn->private_data,
  92                                                              struct dns_tcp_connection);
  93         /* this should never be triggered! */
  94         dns_tcp_terminate_connection(dnsconn, "dns_tcp_recv: called");
  95 }
  96
  97 static void dns_tcp_send(struct stream_connection *conn, uint16_t flags)
  98 {
  99         struct dns_tcp_connection *dnsconn = talloc_get_type(conn->private_data,
 100                                                              struct dns_tcp_connection);
 101         /* this should never be triggered! */
 102         dns_tcp_terminate_connection(dnsconn, "dns_tcp_send: called");
 103 }
 104
 105 struct dns_process_state {
 106         DATA_BLOB *in;
 107         struct dns_server *dns;
 108         struct dns_name_packet in_packet;
 109         struct dns_request_state state;
 110         uint16_t dns_err;
 111         struct dns_name_packet out_packet;
 112         DATA_BLOB out;
 113 };
 114
 115 static void dns_process_done(struct tevent_req *subreq);
 116
 117 static struct tevent_req *dns_process_send(TALLOC_CTX *mem_ctx,
 118                                            struct tevent_context *ev,
 119                                            struct dns_server *dns,
 120                                            const struct tsocket_address *remote_address,
 121                                            const struct tsocket_address *local_address,
 122                                            DATA_BLOB *in)
 123 {
 124         struct tevent_req *req, *subreq;
 125         struct dns_process_state *state;
 126         enum ndr_err_code ndr_err;
 127         WERROR ret;
 128         const char **forwarder = lpcfg_dns_forwarder(dns->task->lp_ctx);
 129         req = tevent_req_create(mem_ctx, &state, struct dns_process_state);
 130         if (req == NULL) {
 131                 return NULL;
 132         }
 133         state->state.mem_ctx = state;
 134         state->in = in;
 135
 136         state->dns = dns;
 137
 138         if (in->length < 12) {
 139                 tevent_req_werror(req, WERR_INVALID_PARAMETER);
 140                 return tevent_req_post(req, ev);
 141         }
 142         dump_data_dbgc(DBGC_DNS, 8, in->data, in->length);
 143
 144         ndr_err = ndr_pull_struct_blob(
 145                 in, state, &state->in_packet,
 146                 (ndr_pull_flags_fn_t)ndr_pull_dns_name_packet);
 147
 148         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 149                 state->dns_err = DNS_RCODE_FORMERR;
 150                 tevent_req_done(req);
 151                 return tevent_req_post(req, ev);
 152         }
 153         if (DEBUGLVLC(DBGC_DNS, 8)) {
 154                 NDR_PRINT_DEBUGC(DBGC_DNS, dns_name_packet, &state->in_packet);
 155         }
 156
 157         if (state->in_packet.operation & DNS_FLAG_REPLY) {
 158                 DEBUG(1, ("Won't reply to replies.\n"));
 159                 tevent_req_werror(req, WERR_INVALID_PARAMETER);
 160                 return tevent_req_post(req, ev);
 161         }
 162
 163         state->state.flags = state->in_packet.operation;
 164         state->state.flags |= DNS_FLAG_REPLY;
 165
 166         state->state.local_address = local_address;
 167         state->state.remote_address = remote_address;
 168
 169         if (forwarder && *forwarder && **forwarder) {
 170                 state->state.flags |= DNS_FLAG_RECURSION_AVAIL;
 171         }
 172
 173         state->out_packet = state->in_packet;
 174
 175         ret = dns_verify_tsig(dns, state, &state->state,
 176                               &state->out_packet, in);
 177         if (!W_ERROR_IS_OK(ret)) {
 178                 state->dns_err = werr_to_dns_err(ret);
 179                 tevent_req_done(req);
 180                 return tevent_req_post(req, ev);
 181         }
 182
 183         switch (state->in_packet.operation & DNS_OPCODE) {
 184         case DNS_OPCODE_QUERY:
 185                 subreq = dns_server_process_query_send(
 186                         state, ev, dns,
 187                         &state->state, &state->in_packet);
 188                 if (tevent_req_nomem(subreq, req)) {
 189                         return tevent_req_post(req, ev);
 190                 }
 191                 tevent_req_set_callback(subreq, dns_process_done, req);
 192                 return req;
 193         case DNS_OPCODE_UPDATE:
 194                 ret = dns_server_process_update(
 195                         dns, &state->state, state, &state->in_packet,
 196                         &state->out_packet.answers, &state->out_packet.ancount,
 197                         &state->out_packet.nsrecs,  &state->out_packet.nscount,
 198                         &state->out_packet.additional,
 199                         &state->out_packet.arcount);
 200                 break;
 201         default:
 202                 ret = WERR_DNS_ERROR_RCODE_NOT_IMPLEMENTED;
 203         }
 204         if (!W_ERROR_IS_OK(ret)) {
 205                 state->dns_err = werr_to_dns_err(ret);
 206         }
 207         tevent_req_done(req);
 208         return tevent_req_post(req, ev);
 209 }
 210
 211 static void dns_process_done(struct tevent_req *subreq)
 212 {
 213         struct tevent_req *req = tevent_req_callback_data(
 214                 subreq, struct tevent_req);
 215         struct dns_process_state *state = tevent_req_data(
 216                 req, struct dns_process_state);
 217         WERROR ret;
 218
 219         ret = dns_server_process_query_recv(
 220                 subreq, state,
 221                 &state->out_packet.answers, &state->out_packet.ancount,
 222                 &state->out_packet.nsrecs,  &state->out_packet.nscount,
 223                 &state->out_packet.additional, &state->out_packet.arcount);
 224         TALLOC_FREE(subreq);
 225
 226         if (!W_ERROR_IS_OK(ret)) {
 227                 state->dns_err = werr_to_dns_err(ret);
 228         }
 229         tevent_req_done(req);
 230 }
 231
 232 static WERROR dns_process_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 233                                DATA_BLOB *out)
 234 {
 235         struct dns_process_state *state = tevent_req_data(
 236                 req, struct dns_process_state);
 237         enum ndr_err_code ndr_err;
 238         WERROR ret;
 239
 240         if (tevent_req_is_werror(req, &ret)) {
 241                 return ret;
 242         }
 243         if ((state->dns_err != DNS_RCODE_OK) &&
 244             (state->dns_err != DNS_RCODE_NXDOMAIN) &&
 245             (state->dns_err != DNS_RCODE_NOTAUTH))
 246         {
 247                 goto drop;
 248         }
 249         if (state->dns_err != DNS_RCODE_OK) {
 250                 state->out_packet.operation |= state->dns_err;
 251         }
 252         state->out_packet.operation |= state->state.flags;
 253
 254         if (state->state.sign) {
 255                 ret = dns_sign_tsig(state->dns, mem_ctx, &state->state,
 256                                     &state->out_packet, 0);
 257                 if (!W_ERROR_IS_OK(ret)) {
 258                         state->dns_err = DNS_RCODE_SERVFAIL;
 259                         goto drop;
 260                 }
 261         }
 262
 263         if (DEBUGLVLC(DBGC_DNS, 8)) {
 264                 NDR_PRINT_DEBUGC(DBGC_DNS, dns_name_packet, &state->out_packet);
 265         }
 266
 267         ndr_err = ndr_push_struct_blob(
 268                 out, mem_ctx, &state->out_packet,
 269                 (ndr_push_flags_fn_t)ndr_push_dns_name_packet);
 270         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 271                 DEBUG(1, ("Failed to push packet: %s!\n",
 272                           ndr_errstr(ndr_err)));
 273                 state->dns_err = DNS_RCODE_SERVFAIL;
 274                 goto drop;
 275         }
 276         return WERR_OK;
 277
 278 drop:
 279         *out = data_blob_talloc(mem_ctx, state->in->data, state->in->length);
 280         if (out->data == NULL) {
 281                 return WERR_NOT_ENOUGH_MEMORY;
 282         }
 283         out->data[2] |= 0x80; /* Toggle DNS_FLAG_REPLY */
 284         out->data[3] |= state->dns_err;
 285         return WERR_OK;
 286 }
 287
 288 struct dns_tcp_call {
 289         struct dns_tcp_connection *dns_conn;
 290         DATA_BLOB in;
 291         DATA_BLOB out;
 292         uint8_t out_hdr[4];
 293         struct iovec out_iov[2];
 294 };
 295
 296 static void dns_tcp_call_process_done(struct tevent_req *subreq);
 297 static void dns_tcp_call_writev_done(struct tevent_req *subreq);
 298
 299 static void dns_tcp_call_loop(struct tevent_req *subreq)
 300 {
 301         struct dns_tcp_connection *dns_conn = tevent_req_callback_data(subreq,
 302                                       struct dns_tcp_connection);
 303         struct dns_server *dns = dns_conn->dns_socket->dns;
 304         struct dns_tcp_call *call;
 305         NTSTATUS status;
 306
 307         call = talloc(dns_conn, struct dns_tcp_call);
 308         if (call == NULL) {
 309                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 310                                 "no memory for dns_tcp_call");
 311                 return;
 312         }
 313         call->dns_conn = dns_conn;
 314
 315         status = tstream_read_pdu_blob_recv(subreq,
 316                                             call,
 317                                             &call->in);
 318         TALLOC_FREE(subreq);
 319         if (!NT_STATUS_IS_OK(status)) {
 320                 const char *reason;
 321
 322                 reason = talloc_asprintf(call, "dns_tcp_call_loop: "
 323                                          "tstream_read_pdu_blob_recv() - %s",
 324                                          nt_errstr(status));
 325                 if (!reason) {
 326                         reason = nt_errstr(status);
 327                 }
 328
 329                 dns_tcp_terminate_connection(dns_conn, reason);
 330                 return;
 331         }
 332
 333         DEBUG(10,("Received DNS TCP packet of length %lu from %s\n",
 334                  (long) call->in.length,
 335                  tsocket_address_string(dns_conn->conn->remote_address, call)));
 336
 337         /* skip length header */
 338         call->in.data += 2;
 339         call->in.length -= 2;
 340
 341         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 342                                   dns_conn->conn->remote_address,
 343                                   dns_conn->conn->local_address,
 344                                   &call->in);
 345         if (subreq == NULL) {
 346                 dns_tcp_terminate_connection(
 347                         dns_conn, "dns_tcp_call_loop: dns_process_send "
 348                         "failed\n");
 349                 return;
 350         }
 351         tevent_req_set_callback(subreq, dns_tcp_call_process_done, call);
 352
 353         /*
 354          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 355          * packet_full_request_u16 provides the pdu length then.
 356          */
 357         subreq = tstream_read_pdu_blob_send(dns_conn,
 358                                             dns_conn->conn->event.ctx,
 359                                             dns_conn->tstream,
 360                                             2, /* initial_read_size */
 361                                             packet_full_request_u16,
 362                                             dns_conn);
 363         if (subreq == NULL) {
 364                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 365                                 "no memory for tstream_read_pdu_blob_send");
 366                 return;
 367         }
 368         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 369 }
 370
 371 static void dns_tcp_call_process_done(struct tevent_req *subreq)
 372 {
 373         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 374                         struct dns_tcp_call);
 375         struct dns_tcp_connection *dns_conn = call->dns_conn;
 376         WERROR err;
 377
 378         err = dns_process_recv(subreq, call, &call->out);
 379         TALLOC_FREE(subreq);
 380         if (!W_ERROR_IS_OK(err)) {
 381                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 382                 dns_tcp_terminate_connection(dns_conn,
 383                                 "dns_tcp_call_loop: process function failed");
 384                 return;
 385         }
 386
 387         /* First add the length of the out buffer */
 388         RSSVAL(call->out_hdr, 0, call->out.length);
 389         call->out_iov[0].iov_base = (char *) call->out_hdr;
 390         call->out_iov[0].iov_len = 2;
 391
 392         call->out_iov[1].iov_base = (char *) call->out.data;
 393         call->out_iov[1].iov_len = call->out.length;
 394
 395         subreq = tstream_writev_queue_send(call,
 396                                            dns_conn->conn->event.ctx,
 397                                            dns_conn->tstream,
 398                                            dns_conn->send_queue,
 399                                            call->out_iov, 2);
 400         if (subreq == NULL) {
 401                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 402                                 "no memory for tstream_writev_queue_send");
 403                 return;
 404         }
 405         tevent_req_set_callback(subreq, dns_tcp_call_writev_done, call);
 406 }
 407
 408 static void dns_tcp_call_writev_done(struct tevent_req *subreq)
 409 {
 410         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 411                         struct dns_tcp_call);
 412         int sys_errno;
 413         int rc;
 414
 415         rc = tstream_writev_queue_recv(subreq, &sys_errno);
 416         TALLOC_FREE(subreq);
 417         if (rc == -1) {
 418                 const char *reason;
 419
 420                 reason = talloc_asprintf(call, "dns_tcp_call_writev_done: "
 421                                          "tstream_writev_queue_recv() - %d:%s",
 422                                          sys_errno, strerror(sys_errno));
 423                 if (!reason) {
 424                         reason = "dns_tcp_call_writev_done: tstream_writev_queue_recv() failed";
 425                 }
 426
 427                 dns_tcp_terminate_connection(call->dns_conn, reason);
 428                 return;
 429         }
 430
 431         /* We don't care about errors */
 432
 433         talloc_free(call);
 434 }
 435
 436 /*
 437   called when we get a new connection
 438 */
 439 static void dns_tcp_accept(struct stream_connection *conn)
 440 {
 441         struct dns_socket *dns_socket;
 442         struct dns_tcp_connection *dns_conn;
 443         struct tevent_req *subreq;
 444         int rc;
 445
 446         dns_conn = talloc_zero(conn, struct dns_tcp_connection);
 447         if (dns_conn == NULL) {
 448                 stream_terminate_connection(conn,
 449                                 "dns_tcp_accept: out of memory");
 450                 return;
 451         }
 452
 453         dns_conn->send_queue = tevent_queue_create(conn, "dns_tcp_accept");
 454         if (dns_conn->send_queue == NULL) {
 455                 stream_terminate_connection(conn,
 456                                 "dns_tcp_accept: out of memory");
 457                 return;
 458         }
 459
 460         dns_socket = talloc_get_type(conn->private_data, struct dns_socket);
 461
 462         TALLOC_FREE(conn->event.fde);
 463
 464         rc = tstream_bsd_existing_socket(dns_conn,
 465                         socket_get_fd(conn->socket),
 466                         &dns_conn->tstream);
 467         if (rc < 0) {
 468                 stream_terminate_connection(conn,
 469                                 "dns_tcp_accept: out of memory");
 470                 return;
 471         }
 472
 473         dns_conn->conn = conn;
 474         dns_conn->dns_socket = dns_socket;
 475         conn->private_data = dns_conn;
 476
 477         /*
 478          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 479          * packet_full_request_u16 provides the pdu length then.
 480          */
 481         subreq = tstream_read_pdu_blob_send(dns_conn,
 482                                             dns_conn->conn->event.ctx,
 483                                             dns_conn->tstream,
 484                                             2, /* initial_read_size */
 485                                             packet_full_request_u16,
 486                                             dns_conn);
 487         if (subreq == NULL) {
 488                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_accept: "
 489                                 "no memory for tstream_read_pdu_blob_send");
 490                 return;
 491         }
 492         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 493 }
 494
 495 static const struct stream_server_ops dns_tcp_stream_ops = {
 496         .name                   = "dns_tcp",
 497         .accept_connection      = dns_tcp_accept,
 498         .recv_handler           = dns_tcp_recv,
 499         .send_handler           = dns_tcp_send
 500 };
 501
 502 struct dns_udp_call {
 503         struct dns_udp_socket *sock;
 504         struct tsocket_address *src;
 505         DATA_BLOB in;
 506         DATA_BLOB out;
 507 };
 508
 509 static void dns_udp_call_process_done(struct tevent_req *subreq);
 510 static void dns_udp_call_sendto_done(struct tevent_req *subreq);
 511
 512 static void dns_udp_call_loop(struct tevent_req *subreq)
 513 {
 514         struct dns_udp_socket *sock = tevent_req_callback_data(subreq,
 515                                       struct dns_udp_socket);
 516         struct dns_server *dns = sock->dns_socket->dns;
 517         struct dns_udp_call *call;
 518         uint8_t *buf;
 519         ssize_t len;
 520         int sys_errno;
 521
 522         call = talloc(sock, struct dns_udp_call);
 523         if (call == NULL) {
 524                 talloc_free(call);
 525                 goto done;
 526         }
 527         call->sock = sock;
 528
 529         len = tdgram_recvfrom_recv(subreq, &sys_errno,
 530                                    call, &buf, &call->src);
 531         TALLOC_FREE(subreq);
 532         if (len == -1) {
 533                 talloc_free(call);
 534                 goto done;
 535         }
 536
 537         call->in.data = buf;
 538         call->in.length = len;
 539
 540         DEBUG(10,("Received DNS UDP packet of length %lu from %s\n",
 541                  (long)call->in.length,
 542                  tsocket_address_string(call->src, call)));
 543
 544         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 545                                   call->src,
 546                                   sock->dns_socket->local_address,
 547                                   &call->in);
 548         if (subreq == NULL) {
 549                 TALLOC_FREE(call);
 550                 goto done;
 551         }
 552         tevent_req_set_callback(subreq, dns_udp_call_process_done, call);
 553
 554 done:
 555         subreq = tdgram_recvfrom_send(sock,
 556                                       sock->dns_socket->dns->task->event_ctx,
 557                                       sock->dgram);
 558         if (subreq == NULL) {
 559                 task_server_terminate(sock->dns_socket->dns->task,
 560                                       "no memory for tdgram_recvfrom_send",
 561                                       true);
 562                 return;
 563         }
 564         tevent_req_set_callback(subreq, dns_udp_call_loop, sock);
 565 }
 566
 567 static void dns_udp_call_process_done(struct tevent_req *subreq)
 568 {
 569         struct dns_udp_call *call = tevent_req_callback_data(
 570                 subreq, struct dns_udp_call);
 571         struct dns_udp_socket *sock = call->sock;
 572         struct dns_server *dns = sock->dns_socket->dns;
 573         WERROR err;
 574
 575         err = dns_process_recv(subreq, call, &call->out);
 576         TALLOC_FREE(subreq);
 577         if (!W_ERROR_IS_OK(err)) {
 578                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 579                 TALLOC_FREE(call);
 580                 return;
 581         }
 582
 583         subreq = tdgram_sendto_queue_send(call,
 584                                           dns->task->event_ctx,
 585                                           sock->dgram,
 586                                           sock->send_queue,
 587                                           call->out.data,
 588                                           call->out.length,
 589                                           call->src);
 590         if (subreq == NULL) {
 591                 talloc_free(call);
 592                 return;
 593         }
 594         tevent_req_set_callback(subreq, dns_udp_call_sendto_done, call);
 595
 596 }
 597 static void dns_udp_call_sendto_done(struct tevent_req *subreq)
 598 {
 599         struct dns_udp_call *call = tevent_req_callback_data(subreq,
 600                                        struct dns_udp_call);
 601         int sys_errno;
 602
 603         tdgram_sendto_queue_recv(subreq, &sys_errno);
 604
 605         /* We don't care about errors */
 606
 607         talloc_free(call);
 608 }
 609
 610 /*
 611   start listening on the given address
 612 */
 613 static NTSTATUS dns_add_socket(struct dns_server *dns,
 614                                const struct model_ops *model_ops,
 615                                const char *name,
 616                                const char *address,
 617                                uint16_t port)
 618 {
 619         struct dns_socket *dns_socket;
 620         struct dns_udp_socket *dns_udp_socket;
 621         struct tevent_req *udpsubreq;
 622         NTSTATUS status;
 623         int ret;
 624
 625         dns_socket = talloc(dns, struct dns_socket);
 626         NT_STATUS_HAVE_NO_MEMORY(dns_socket);
 627
 628         dns_socket->dns = dns;
 629
 630         ret = tsocket_address_inet_from_strings(dns_socket, "ip",
 631                                                 address, port,
 632                                                 &dns_socket->local_address);
 633         if (ret != 0) {
 634                 status = map_nt_error_from_unix_common(errno);
 635                 return status;
 636         }
 637
 638         status = stream_setup_socket(dns->task,
 639                                      dns->task->event_ctx,
 640                                      dns->task->lp_ctx,
 641                                      model_ops,
 642                                      &dns_tcp_stream_ops,
 643                                      "ip", address, &port,
 644                                      lpcfg_socket_options(dns->task->lp_ctx),
 645                                      dns_socket,
 646                                      dns->task->process_context);
 647         if (!NT_STATUS_IS_OK(status)) {
 648                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 649                          address, port, nt_errstr(status)));
 650                 talloc_free(dns_socket);
 651                 return status;
 652         }
 653
 654         dns_udp_socket = talloc(dns_socket, struct dns_udp_socket);
 655         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket);
 656
 657         dns_udp_socket->dns_socket = dns_socket;
 658
 659         ret = tdgram_inet_udp_socket(dns_socket->local_address,
 660                                      NULL,
 661                                      dns_udp_socket,
 662                                      &dns_udp_socket->dgram);
 663         if (ret != 0) {
 664                 status = map_nt_error_from_unix_common(errno);
 665                 DEBUG(0,("Failed to bind to %s:%u UDP - %s\n",
 666                          address, port, nt_errstr(status)));
 667                 return status;
 668         }
 669
 670         dns_udp_socket->send_queue = tevent_queue_create(dns_udp_socket,
 671                                                          "dns_udp_send_queue");
 672         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket->send_queue);
 673
 674         udpsubreq = tdgram_recvfrom_send(dns_udp_socket,
 675                                          dns->task->event_ctx,
 676                                          dns_udp_socket->dgram);
 677         NT_STATUS_HAVE_NO_MEMORY(udpsubreq);
 678         tevent_req_set_callback(udpsubreq, dns_udp_call_loop, dns_udp_socket);
 679
 680         return NT_STATUS_OK;
 681 }
 682
 683 /*
 684   setup our listening sockets on the configured network interfaces
 685 */
 686 static NTSTATUS dns_startup_interfaces(struct dns_server *dns,
 687                                        struct interface *ifaces)
 688 {
 689         const struct model_ops *model_ops;
 690         int num_interfaces;
 691         TALLOC_CTX *tmp_ctx = talloc_new(dns);
 692         NTSTATUS status;
 693         int i;
 694
 695         /* within the dns task we want to be a single process, so
 696            ask for the single process model ops and pass these to the
 697            stream_setup_socket() call. */
 698         model_ops = process_model_startup("single");
 699         if (!model_ops) {
 700                 DEBUG(0,("Can't find 'single' process model_ops\n"));
 701                 return NT_STATUS_INTERNAL_ERROR;
 702         }
 703
 704         if (ifaces != NULL) {
 705                 num_interfaces = iface_list_count(ifaces);
 706
 707                 for (i=0; i<num_interfaces; i++) {
 708                         const char *address = talloc_strdup(tmp_ctx,
 709                                                             iface_list_n_ip(ifaces, i));
 710
 711                         status = dns_add_socket(dns, model_ops, "dns", address,
 712                                                 DNS_SERVICE_PORT);
 713                         NT_STATUS_NOT_OK_RETURN(status);
 714                 }
 715         } else {
 716                 int num_binds = 0;
 717                 char **wcard;
 718                 wcard = iface_list_wildcard(tmp_ctx);
 719                 if (wcard == NULL) {
 720                         DEBUG(0, ("No wildcard address available\n"));
 721                         return NT_STATUS_INTERNAL_ERROR;
 722                 }
 723                 for (i = 0; wcard[i] != NULL; i++) {
 724                         status = dns_add_socket(dns, model_ops, "dns", wcard[i],
 725                                                 DNS_SERVICE_PORT);
 726                         if (NT_STATUS_IS_OK(status)) {
 727                                 num_binds++;
 728                         }
 729                 }
 730                 if (num_binds == 0) {
 731                         talloc_free(tmp_ctx);
 732                         return NT_STATUS_INVALID_PARAMETER_MIX;
 733                 }
 734         }
 735
 736         talloc_free(tmp_ctx);
 737
 738         return NT_STATUS_OK;
 739 }
 740
 741 static struct dns_server_tkey_store *tkey_store_init(TALLOC_CTX *mem_ctx,
 742                                                      uint16_t size)
 743 {
 744         struct dns_server_tkey_store *buffer = talloc_zero(mem_ctx,
 745                                                 struct dns_server_tkey_store);
 746
 747         if (buffer == NULL) {
 748                 return NULL;
 749         }
 750
 751         buffer->size = size;
 752         buffer->next_idx = 0;
 753
 754         buffer->tkeys = talloc_zero_array(buffer, struct dns_server_tkey *, size);
 755         if (buffer->tkeys == NULL) {
 756                 TALLOC_FREE(buffer);
 757         }
 758
 759         return buffer;
 760 }
 761
 762 static NTSTATUS dns_server_reload_zones(struct dns_server *dns)
 763 {
 764         NTSTATUS status;
 765         struct dns_server_zone *new_list = NULL;
 766         struct dns_server_zone *old_list = NULL;
 767         struct dns_server_zone *old_zone;
 768         status = dns_common_zones(dns->samdb, dns, NULL, &new_list);
 769         if (!NT_STATUS_IS_OK(status)) {
 770                 return status;
 771         }
 772         dns->zones = new_list;
 773         while ((old_zone = DLIST_TAIL(old_list)) != NULL) {
 774                 DLIST_REMOVE(old_list, old_zone);
 775                 talloc_free(old_zone);
 776         }
 777
 778         return NT_STATUS_OK;
 779 }
 780
 781 /**
 782  * Called when the internal DNS server should reload the zones from DB, for
 783  * example, when zones are added or deleted through RPC or replicated by
 784  * inbound DRS.
 785  */
 786 static NTSTATUS dns_reload_zones(struct irpc_message *msg,
 787                                  struct dnssrv_reload_dns_zones *r)
 788 {
 789         struct dns_server *dns;
 790
 791         dns = talloc_get_type(msg->private_data, struct dns_server);
 792         if (dns == NULL) {
 793                 r->out.result = NT_STATUS_INTERNAL_ERROR;
 794                 return NT_STATUS_INTERNAL_ERROR;
 795         }
 796
 797         r->out.result = dns_server_reload_zones(dns);
 798
 799         return NT_STATUS_OK;
 800 }
 801
 802 static void dns_task_init(struct task_server *task)
 803 {
 804         struct dns_server *dns;
 805         NTSTATUS status;
 806         struct interface *ifaces = NULL;
 807         int ret;
 808         static const char * const attrs_none[] = { NULL};
 809         struct ldb_message *dns_acc;
 810         char *hostname_lower;
 811         char *dns_spn;
 812
 813         switch (lpcfg_server_role(task->lp_ctx)) {
 814         case ROLE_STANDALONE:
 815                 task_server_terminate(task, "dns: no DNS required in standalone configuration", false);
 816                 return;
 817         case ROLE_DOMAIN_MEMBER:
 818                 task_server_terminate(task, "dns: no DNS required in member server configuration", false);
 819                 return;
 820         case ROLE_ACTIVE_DIRECTORY_DC:
 821                 /* Yes, we want a DNS */
 822                 break;
 823         }
 824
 825         if (lpcfg_interfaces(task->lp_ctx) && lpcfg_bind_interfaces_only(task->lp_ctx)) {
 826                 load_interface_list(task, task->lp_ctx, &ifaces);
 827
 828                 if (iface_list_count(ifaces) == 0) {
 829                         task_server_terminate(task, "dns: no network interfaces configured", false);
 830                         return;
 831                 }
 832         }
 833
 834         task_server_set_title(task, "task[dns]");
 835
 836         dns = talloc_zero(task, struct dns_server);
 837         if (dns == NULL) {
 838                 task_server_terminate(task, "dns: out of memory", true);
 839                 return;
 840         }
 841
 842         dns->task = task;
 843         /*FIXME: Make this a configurable option */
 844         dns->max_payload = 4096;
 845
 846         dns->server_credentials = cli_credentials_init(dns);
 847         if (!dns->server_credentials) {
 848                 task_server_terminate(task, "Failed to init server credentials\n", true);
 849                 return;
 850         }
 851
 852         dns->samdb = samdb_connect(dns, dns->task->event_ctx, dns->task->lp_ctx,
 853                               system_session(dns->task->lp_ctx), 0);
 854         if (!dns->samdb) {
 855                 task_server_terminate(task, "dns: samdb_connect failed", true);
 856                 return;
 857         }
 858
 859         cli_credentials_set_conf(dns->server_credentials, task->lp_ctx);
 860
 861         hostname_lower = strlower_talloc(dns, lpcfg_netbios_name(task->lp_ctx));
 862         dns_spn = talloc_asprintf(dns, "DNS/%s.%s",
 863                                   hostname_lower,
 864                                   lpcfg_dnsdomain(task->lp_ctx));
 865         TALLOC_FREE(hostname_lower);
 866
 867         ret = dsdb_search_one(dns->samdb, dns, &dns_acc,
 868                               ldb_get_default_basedn(dns->samdb), LDB_SCOPE_SUBTREE,
 869                               attrs_none, 0, "(servicePrincipalName=%s)",
 870                               dns_spn);
 871         if (ret == LDB_SUCCESS) {
 872                 TALLOC_FREE(dns_acc);
 873                 if (!dns_spn) {
 874                         task_server_terminate(task, "dns: talloc_asprintf failed", true);
 875                         return;
 876                 }
 877                 status = cli_credentials_set_stored_principal(dns->server_credentials, task->lp_ctx, dns_spn);
 878                 if (!NT_STATUS_IS_OK(status)) {
 879                         task_server_terminate(task,
 880                                               talloc_asprintf(task, "Failed to obtain server credentials for DNS, "
 881                                                               "despite finding it in the samdb! %s\n",
 882                                                               nt_errstr(status)),
 883                                               true);
 884                         return;
 885                 }
 886         } else {
 887                 TALLOC_FREE(dns_spn);
 888                 status = cli_credentials_set_machine_account(dns->server_credentials, task->lp_ctx);
 889                 if (!NT_STATUS_IS_OK(status)) {
 890                         task_server_terminate(task,
 891                                               talloc_asprintf(task, "Failed to obtain server credentials, perhaps a standalone server?: %s\n",
 892                                                               nt_errstr(status)),
 893                                               true);
 894                         return;
 895                 }
 896         }
 897
 898         dns->tkeys = tkey_store_init(dns, TKEY_BUFFER_SIZE);
 899         if (!dns->tkeys) {
 900                 task_server_terminate(task, "Failed to allocate tkey storage\n", true);
 901                 return;
 902         }
 903
 904         status = dns_server_reload_zones(dns);
 905         if (!NT_STATUS_IS_OK(status)) {
 906                 task_server_terminate(task, "dns: failed to load DNS zones", true);
 907                 return;
 908         }
 909
 910         status = dns_startup_interfaces(dns, ifaces);
 911         if (!NT_STATUS_IS_OK(status)) {
 912                 task_server_terminate(task, "dns failed to setup interfaces", true);
 913                 return;
 914         }
 915
 916         /* Setup the IRPC interface and register handlers */
 917         status = irpc_add_name(task->msg_ctx, "dnssrv");
 918         if (!NT_STATUS_IS_OK(status)) {
 919                 task_server_terminate(task, "dns: failed to register IRPC name", true);
 920                 return;
 921         }
 922
 923         status = IRPC_REGISTER(task->msg_ctx, irpc, DNSSRV_RELOAD_DNS_ZONES,
 924                                dns_reload_zones, dns);
 925         if (!NT_STATUS_IS_OK(status)) {
 926                 task_server_terminate(task, "dns: failed to setup reload handler", true);
 927                 return;
 928         }
 929 }
 930
 931 NTSTATUS server_service_dns_init(TALLOC_CTX *ctx)
 932 {
 933         struct service_details details = {
 934                 .inhibit_fork_on_accept = true,
 935                 .inhibit_pre_fork = true,
 936         };
 937         return register_server_service(ctx, "dns", dns_task_init, &details);
 938 }