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                 goto drop;
 239         }
 240         state->out_packet.operation |= state->state.flags;
 241
 242         if (state->state.sign) {
 243                 ret = dns_sign_tsig(state->dns, mem_ctx, &state->state,
 244                                     &state->out_packet, 0);
 245                 if (!W_ERROR_IS_OK(ret)) {
 246                         state->dns_err = DNS_RCODE_SERVFAIL;
 247                         goto drop;
 248                 }
 249         }
 250
 251         if (DEBUGLVLC(DBGC_DNS, 8)) {
 252                 NDR_PRINT_DEBUGC(DBGC_DNS, dns_name_packet, &state->out_packet);
 253         }
 254
 255         ndr_err = ndr_push_struct_blob(
 256                 out, mem_ctx, &state->out_packet,
 257                 (ndr_push_flags_fn_t)ndr_push_dns_name_packet);
 258         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 259                 DEBUG(1, ("Failed to push packet: %s!\n",
 260                           ndr_errstr(ndr_err)));
 261                 state->dns_err = DNS_RCODE_SERVFAIL;
 262                 goto drop;
 263         }
 264         return WERR_OK;
 265
 266 drop:
 267         *out = data_blob_talloc(mem_ctx, state->in->data, state->in->length);
 268         if (out->data == NULL) {
 269                 return WERR_NOMEM;
 270         }
 271         out->data[2] |= 0x80; /* Toggle DNS_FLAG_REPLY */
 272         out->data[3] |= state->dns_err;
 273         return WERR_OK;
 274 }
 275
 276 struct dns_tcp_call {
 277         struct dns_tcp_connection *dns_conn;
 278         DATA_BLOB in;
 279         DATA_BLOB out;
 280         uint8_t out_hdr[4];
 281         struct iovec out_iov[2];
 282 };
 283
 284 static void dns_tcp_call_process_done(struct tevent_req *subreq);
 285 static void dns_tcp_call_writev_done(struct tevent_req *subreq);
 286
 287 static void dns_tcp_call_loop(struct tevent_req *subreq)
 288 {
 289         struct dns_tcp_connection *dns_conn = tevent_req_callback_data(subreq,
 290                                       struct dns_tcp_connection);
 291         struct dns_server *dns = dns_conn->dns_socket->dns;
 292         struct dns_tcp_call *call;
 293         NTSTATUS status;
 294
 295         call = talloc(dns_conn, struct dns_tcp_call);
 296         if (call == NULL) {
 297                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 298                                 "no memory for dns_tcp_call");
 299                 return;
 300         }
 301         call->dns_conn = dns_conn;
 302
 303         status = tstream_read_pdu_blob_recv(subreq,
 304                                             call,
 305                                             &call->in);
 306         TALLOC_FREE(subreq);
 307         if (!NT_STATUS_IS_OK(status)) {
 308                 const char *reason;
 309
 310                 reason = talloc_asprintf(call, "dns_tcp_call_loop: "
 311                                          "tstream_read_pdu_blob_recv() - %s",
 312                                          nt_errstr(status));
 313                 if (!reason) {
 314                         reason = nt_errstr(status);
 315                 }
 316
 317                 dns_tcp_terminate_connection(dns_conn, reason);
 318                 return;
 319         }
 320
 321         DEBUG(10,("Received DNS TCP packet of length %lu from %s\n",
 322                  (long) call->in.length,
 323                  tsocket_address_string(dns_conn->conn->remote_address, call)));
 324
 325         /* skip length header */
 326         call->in.data += 2;
 327         call->in.length -= 2;
 328
 329         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 330                                   &call->in);
 331         if (subreq == NULL) {
 332                 dns_tcp_terminate_connection(
 333                         dns_conn, "dns_tcp_call_loop: dns_process_send "
 334                         "failed\n");
 335                 return;
 336         }
 337         tevent_req_set_callback(subreq, dns_tcp_call_process_done, call);
 338
 339         /*
 340          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 341          * packet_full_request_u16 provides the pdu length then.
 342          */
 343         subreq = tstream_read_pdu_blob_send(dns_conn,
 344                                             dns_conn->conn->event.ctx,
 345                                             dns_conn->tstream,
 346                                             2, /* initial_read_size */
 347                                             packet_full_request_u16,
 348                                             dns_conn);
 349         if (subreq == NULL) {
 350                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 351                                 "no memory for tstream_read_pdu_blob_send");
 352                 return;
 353         }
 354         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 355 }
 356
 357 static void dns_tcp_call_process_done(struct tevent_req *subreq)
 358 {
 359         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 360                         struct dns_tcp_call);
 361         struct dns_tcp_connection *dns_conn = call->dns_conn;
 362         WERROR err;
 363
 364         err = dns_process_recv(subreq, call, &call->out);
 365         TALLOC_FREE(subreq);
 366         if (!W_ERROR_IS_OK(err)) {
 367                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 368                 dns_tcp_terminate_connection(dns_conn,
 369                                 "dns_tcp_call_loop: process function failed");
 370                 return;
 371         }
 372
 373         /* First add the length of the out buffer */
 374         RSSVAL(call->out_hdr, 0, call->out.length);
 375         call->out_iov[0].iov_base = (char *) call->out_hdr;
 376         call->out_iov[0].iov_len = 2;
 377
 378         call->out_iov[1].iov_base = (char *) call->out.data;
 379         call->out_iov[1].iov_len = call->out.length;
 380
 381         subreq = tstream_writev_queue_send(call,
 382                                            dns_conn->conn->event.ctx,
 383                                            dns_conn->tstream,
 384                                            dns_conn->send_queue,
 385                                            call->out_iov, 2);
 386         if (subreq == NULL) {
 387                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 388                                 "no memory for tstream_writev_queue_send");
 389                 return;
 390         }
 391         tevent_req_set_callback(subreq, dns_tcp_call_writev_done, call);
 392 }
 393
 394 static void dns_tcp_call_writev_done(struct tevent_req *subreq)
 395 {
 396         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 397                         struct dns_tcp_call);
 398         int sys_errno;
 399         int rc;
 400
 401         rc = tstream_writev_queue_recv(subreq, &sys_errno);
 402         TALLOC_FREE(subreq);
 403         if (rc == -1) {
 404                 const char *reason;
 405
 406                 reason = talloc_asprintf(call, "dns_tcp_call_writev_done: "
 407                                          "tstream_writev_queue_recv() - %d:%s",
 408                                          sys_errno, strerror(sys_errno));
 409                 if (!reason) {
 410                         reason = "dns_tcp_call_writev_done: tstream_writev_queue_recv() failed";
 411                 }
 412
 413                 dns_tcp_terminate_connection(call->dns_conn, reason);
 414                 return;
 415         }
 416
 417         /* We don't care about errors */
 418
 419         talloc_free(call);
 420 }
 421
 422 /*
 423   called when we get a new connection
 424 */
 425 static void dns_tcp_accept(struct stream_connection *conn)
 426 {
 427         struct dns_socket *dns_socket;
 428         struct dns_tcp_connection *dns_conn;
 429         struct tevent_req *subreq;
 430         int rc;
 431
 432         dns_conn = talloc_zero(conn, struct dns_tcp_connection);
 433         if (dns_conn == NULL) {
 434                 stream_terminate_connection(conn,
 435                                 "dns_tcp_accept: out of memory");
 436                 return;
 437         }
 438
 439         dns_conn->send_queue = tevent_queue_create(conn, "dns_tcp_accept");
 440         if (dns_conn->send_queue == NULL) {
 441                 stream_terminate_connection(conn,
 442                                 "dns_tcp_accept: out of memory");
 443                 return;
 444         }
 445
 446         dns_socket = talloc_get_type(conn->private_data, struct dns_socket);
 447
 448         TALLOC_FREE(conn->event.fde);
 449
 450         rc = tstream_bsd_existing_socket(dns_conn,
 451                         socket_get_fd(conn->socket),
 452                         &dns_conn->tstream);
 453         if (rc < 0) {
 454                 stream_terminate_connection(conn,
 455                                 "dns_tcp_accept: out of memory");
 456                 return;
 457         }
 458
 459         dns_conn->conn = conn;
 460         dns_conn->dns_socket = dns_socket;
 461         conn->private_data = dns_conn;
 462
 463         /*
 464          * The dns tcp pdu's has the length as 2 byte (initial_read_size),
 465          * packet_full_request_u16 provides the pdu length then.
 466          */
 467         subreq = tstream_read_pdu_blob_send(dns_conn,
 468                                             dns_conn->conn->event.ctx,
 469                                             dns_conn->tstream,
 470                                             2, /* initial_read_size */
 471                                             packet_full_request_u16,
 472                                             dns_conn);
 473         if (subreq == NULL) {
 474                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_accept: "
 475                                 "no memory for tstream_read_pdu_blob_send");
 476                 return;
 477         }
 478         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 479 }
 480
 481 static const struct stream_server_ops dns_tcp_stream_ops = {
 482         .name                   = "dns_tcp",
 483         .accept_connection      = dns_tcp_accept,
 484         .recv_handler           = dns_tcp_recv,
 485         .send_handler           = dns_tcp_send
 486 };
 487
 488 struct dns_udp_call {
 489         struct dns_udp_socket *sock;
 490         struct tsocket_address *src;
 491         DATA_BLOB in;
 492         DATA_BLOB out;
 493 };
 494
 495 static void dns_udp_call_process_done(struct tevent_req *subreq);
 496 static void dns_udp_call_sendto_done(struct tevent_req *subreq);
 497
 498 static void dns_udp_call_loop(struct tevent_req *subreq)
 499 {
 500         struct dns_udp_socket *sock = tevent_req_callback_data(subreq,
 501                                       struct dns_udp_socket);
 502         struct dns_server *dns = sock->dns_socket->dns;
 503         struct dns_udp_call *call;
 504         uint8_t *buf;
 505         ssize_t len;
 506         int sys_errno;
 507
 508         call = talloc(sock, struct dns_udp_call);
 509         if (call == NULL) {
 510                 talloc_free(call);
 511                 goto done;
 512         }
 513         call->sock = sock;
 514
 515         len = tdgram_recvfrom_recv(subreq, &sys_errno,
 516                                    call, &buf, &call->src);
 517         TALLOC_FREE(subreq);
 518         if (len == -1) {
 519                 talloc_free(call);
 520                 goto done;
 521         }
 522
 523         call->in.data = buf;
 524         call->in.length = len;
 525
 526         DEBUG(10,("Received DNS UDP packet of length %lu from %s\n",
 527                  (long)call->in.length,
 528                  tsocket_address_string(call->src, call)));
 529
 530         subreq = dns_process_send(call, dns->task->event_ctx, dns,
 531                                   &call->in);
 532         if (subreq == NULL) {
 533                 TALLOC_FREE(call);
 534                 goto done;
 535         }
 536         tevent_req_set_callback(subreq, dns_udp_call_process_done, call);
 537
 538 done:
 539         subreq = tdgram_recvfrom_send(sock,
 540                                       sock->dns_socket->dns->task->event_ctx,
 541                                       sock->dgram);
 542         if (subreq == NULL) {
 543                 task_server_terminate(sock->dns_socket->dns->task,
 544                                       "no memory for tdgram_recvfrom_send",
 545                                       true);
 546                 return;
 547         }
 548         tevent_req_set_callback(subreq, dns_udp_call_loop, sock);
 549 }
 550
 551 static void dns_udp_call_process_done(struct tevent_req *subreq)
 552 {
 553         struct dns_udp_call *call = tevent_req_callback_data(
 554                 subreq, struct dns_udp_call);
 555         struct dns_udp_socket *sock = call->sock;
 556         struct dns_server *dns = sock->dns_socket->dns;
 557         WERROR err;
 558
 559         err = dns_process_recv(subreq, call, &call->out);
 560         TALLOC_FREE(subreq);
 561         if (!W_ERROR_IS_OK(err)) {
 562                 DEBUG(1, ("dns_process returned %s\n", win_errstr(err)));
 563                 TALLOC_FREE(call);
 564                 return;
 565         }
 566
 567         subreq = tdgram_sendto_queue_send(call,
 568                                           dns->task->event_ctx,
 569                                           sock->dgram,
 570                                           sock->send_queue,
 571                                           call->out.data,
 572                                           call->out.length,
 573                                           call->src);
 574         if (subreq == NULL) {
 575                 talloc_free(call);
 576                 return;
 577         }
 578         tevent_req_set_callback(subreq, dns_udp_call_sendto_done, call);
 579
 580 }
 581 static void dns_udp_call_sendto_done(struct tevent_req *subreq)
 582 {
 583         struct dns_udp_call *call = tevent_req_callback_data(subreq,
 584                                        struct dns_udp_call);
 585         int sys_errno;
 586
 587         tdgram_sendto_queue_recv(subreq, &sys_errno);
 588
 589         /* We don't care about errors */
 590
 591         talloc_free(call);
 592 }
 593
 594 /*
 595   start listening on the given address
 596 */
 597 static NTSTATUS dns_add_socket(struct dns_server *dns,
 598                                const struct model_ops *model_ops,
 599                                const char *name,
 600                                const char *address,
 601                                uint16_t port)
 602 {
 603         struct dns_socket *dns_socket;
 604         struct dns_udp_socket *dns_udp_socket;
 605         struct tevent_req *udpsubreq;
 606         NTSTATUS status;
 607         int ret;
 608
 609         dns_socket = talloc(dns, struct dns_socket);
 610         NT_STATUS_HAVE_NO_MEMORY(dns_socket);
 611
 612         dns_socket->dns = dns;
 613
 614         ret = tsocket_address_inet_from_strings(dns_socket, "ip",
 615                                                 address, port,
 616                                                 &dns_socket->local_address);
 617         if (ret != 0) {
 618                 status = map_nt_error_from_unix_common(errno);
 619                 return status;
 620         }
 621
 622         status = stream_setup_socket(dns->task,
 623                                      dns->task->event_ctx,
 624                                      dns->task->lp_ctx,
 625                                      model_ops,
 626                                      &dns_tcp_stream_ops,
 627                                      "ip", address, &port,
 628                                      lpcfg_socket_options(dns->task->lp_ctx),
 629                                      dns_socket);
 630         if (!NT_STATUS_IS_OK(status)) {
 631                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 632                          address, port, nt_errstr(status)));
 633                 talloc_free(dns_socket);
 634                 return status;
 635         }
 636
 637         dns_udp_socket = talloc(dns_socket, struct dns_udp_socket);
 638         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket);
 639
 640         dns_udp_socket->dns_socket = dns_socket;
 641
 642         ret = tdgram_inet_udp_socket(dns_socket->local_address,
 643                                      NULL,
 644                                      dns_udp_socket,
 645                                      &dns_udp_socket->dgram);
 646         if (ret != 0) {
 647                 status = map_nt_error_from_unix_common(errno);
 648                 DEBUG(0,("Failed to bind to %s:%u UDP - %s\n",
 649                          address, port, nt_errstr(status)));
 650                 return status;
 651         }
 652
 653         dns_udp_socket->send_queue = tevent_queue_create(dns_udp_socket,
 654                                                          "dns_udp_send_queue");
 655         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket->send_queue);
 656
 657         udpsubreq = tdgram_recvfrom_send(dns_udp_socket,
 658                                          dns->task->event_ctx,
 659                                          dns_udp_socket->dgram);
 660         NT_STATUS_HAVE_NO_MEMORY(udpsubreq);
 661         tevent_req_set_callback(udpsubreq, dns_udp_call_loop, dns_udp_socket);
 662
 663         return NT_STATUS_OK;
 664 }
 665
 666 /*
 667   setup our listening sockets on the configured network interfaces
 668 */
 669 static NTSTATUS dns_startup_interfaces(struct dns_server *dns,
 670                                        struct interface *ifaces)
 671 {
 672         const struct model_ops *model_ops;
 673         int num_interfaces;
 674         TALLOC_CTX *tmp_ctx = talloc_new(dns);
 675         NTSTATUS status;
 676         int i;
 677
 678         /* within the dns task we want to be a single process, so
 679            ask for the single process model ops and pass these to the
 680            stream_setup_socket() call. */
 681         model_ops = process_model_startup("single");
 682         if (!model_ops) {
 683                 DEBUG(0,("Can't find 'single' process model_ops\n"));
 684                 return NT_STATUS_INTERNAL_ERROR;
 685         }
 686
 687         if (ifaces != NULL) {
 688                 num_interfaces = iface_list_count(ifaces);
 689
 690                 for (i=0; i<num_interfaces; i++) {
 691                         const char *address = talloc_strdup(tmp_ctx,
 692                                                             iface_list_n_ip(ifaces, i));
 693
 694                         status = dns_add_socket(dns, model_ops, "dns", address,
 695                                                 DNS_SERVICE_PORT);
 696                         NT_STATUS_NOT_OK_RETURN(status);
 697                 }
 698         } else {
 699                 int num_binds = 0;
 700                 char **wcard;
 701                 wcard = iface_list_wildcard(tmp_ctx);
 702                 if (wcard == NULL) {
 703                         DEBUG(0, ("No wildcard address available\n"));
 704                         return NT_STATUS_INTERNAL_ERROR;
 705                 }
 706                 for (i = 0; wcard[i] != NULL; i++) {
 707                         status = dns_add_socket(dns, model_ops, "dns", wcard[i],
 708                                                 DNS_SERVICE_PORT);
 709                         if (NT_STATUS_IS_OK(status)) {
 710                                 num_binds++;
 711                         }
 712                 }
 713                 if (num_binds == 0) {
 714                         talloc_free(tmp_ctx);
 715                         return NT_STATUS_INVALID_PARAMETER_MIX;
 716                 }
 717         }
 718
 719         talloc_free(tmp_ctx);
 720
 721         return NT_STATUS_OK;
 722 }
 723
 724 static int dns_server_sort_zones(struct ldb_message **m1, struct ldb_message **m2)
 725 {
 726         const char *n1, *n2;
 727         size_t l1, l2;
 728
 729         n1 = ldb_msg_find_attr_as_string(*m1, "name", NULL);
 730         n2 = ldb_msg_find_attr_as_string(*m2, "name", NULL);
 731
 732         l1 = strlen(n1);
 733         l2 = strlen(n2);
 734
 735         /* If the string lengths are not equal just sort by length */
 736         if (l1 != l2) {
 737                 /* If m1 is the larger zone name, return it first */
 738                 return l2 - l1;
 739         }
 740
 741         /*TODO: We need to compare DNs here, we want the DomainDNSZones first */
 742         return 0;
 743 }
 744
 745 static struct dns_server_tkey_store *tkey_store_init(TALLOC_CTX *mem_ctx,
 746                                                      uint16_t size)
 747 {
 748         struct dns_server_tkey_store *buffer = talloc_zero(mem_ctx,
 749                                                 struct dns_server_tkey_store);
 750
 751         if (buffer == NULL) {
 752                 return NULL;
 753         }
 754
 755         buffer->size = size;
 756         buffer->next_idx = 0;
 757
 758         buffer->tkeys = talloc_zero_array(buffer, struct dns_server_tkey *, size);
 759         if (buffer->tkeys == NULL) {
 760                 TALLOC_FREE(buffer);
 761         }
 762
 763         return buffer;
 764 }
 765
 766 static NTSTATUS dns_server_reload_zones(struct dns_server *dns)
 767 {
 768         int ret;
 769         static const char * const attrs[] = { "name", NULL};
 770         struct ldb_result *res;
 771         int i;
 772         struct dns_server_zone *new_list = NULL;
 773         struct dns_server_zone *old_list = NULL;
 774         struct dns_server_zone *old_zone;
 775
 776         // TODO: this search does not work against windows
 777         ret = dsdb_search(dns->samdb, dns, &res, NULL, LDB_SCOPE_SUBTREE,
 778                           attrs, DSDB_SEARCH_SEARCH_ALL_PARTITIONS, "(objectClass=dnsZone)");
 779         if (ret != LDB_SUCCESS) {
 780                 return NT_STATUS_INTERNAL_DB_CORRUPTION;
 781         }
 782
 783         TYPESAFE_QSORT(res->msgs, res->count, dns_server_sort_zones);
 784
 785         for (i=0; i < res->count; i++) {
 786                 struct dns_server_zone *z;
 787
 788                 z = talloc_zero(dns, struct dns_server_zone);
 789                 if (z == NULL) {
 790                         return NT_STATUS_NO_MEMORY;
 791                 }
 792
 793                 z->name = ldb_msg_find_attr_as_string(res->msgs[i], "name", NULL);
 794                 z->dn = talloc_move(z, &res->msgs[i]->dn);
 795                 /*
 796                  * Ignore the RootDNSServers zone and zones that we don't support yet
 797                  * RootDNSServers should never be returned (Windows DNS server don't)
 798                  * ..TrustAnchors should never be returned as is, (Windows returns
 799                  * TrustAnchors) and for the moment we don't support DNSSEC so we'd better
 800                  * not return this zone.
 801                  */
 802                 if ((strcmp(z->name, "RootDNSServers") == 0) ||
 803                     (strcmp(z->name, "..TrustAnchors") == 0))
 804                 {
 805                         DEBUG(10, ("Ignoring zone %s\n", z->name));
 806                         talloc_free(z);
 807                         continue;
 808                 }
 809                 DLIST_ADD_END(new_list, z, NULL);
 810         }
 811
 812         old_list = dns->zones;
 813         dns->zones = new_list;
 814         while ((old_zone = DLIST_TAIL(old_list)) != NULL) {
 815                 DLIST_REMOVE(old_list, old_zone);
 816                 talloc_free(old_zone);
 817         }
 818
 819         return NT_STATUS_OK;
 820 }
 821
 822 /**
 823  * Called when the internal DNS server should reload the zones from DB, for
 824  * example, when zones are added or deleted through RPC or replicated by
 825  * inbound DRS.
 826  */
 827 static NTSTATUS dns_reload_zones(struct irpc_message *msg,
 828                                  struct dnssrv_reload_dns_zones *r)
 829 {
 830         struct dns_server *dns;
 831
 832         dns = talloc_get_type(msg->private_data, struct dns_server);
 833         if (dns == NULL) {
 834                 r->out.result = NT_STATUS_INTERNAL_ERROR;
 835                 return NT_STATUS_INTERNAL_ERROR;
 836         }
 837
 838         r->out.result = dns_server_reload_zones(dns);
 839
 840         return NT_STATUS_OK;
 841 }
 842
 843 static void dns_task_init(struct task_server *task)
 844 {
 845         struct dns_server *dns;
 846         NTSTATUS status;
 847         struct interface *ifaces = NULL;
 848         int ret;
 849         static const char * const attrs_none[] = { NULL};
 850         struct ldb_message *dns_acc;
 851         char *hostname_lower;
 852         char *dns_spn;
 853
 854         switch (lpcfg_server_role(task->lp_ctx)) {
 855         case ROLE_STANDALONE:
 856                 task_server_terminate(task, "dns: no DNS required in standalone configuration", false);
 857                 return;
 858         case ROLE_DOMAIN_MEMBER:
 859                 task_server_terminate(task, "dns: no DNS required in member server configuration", false);
 860                 return;
 861         case ROLE_ACTIVE_DIRECTORY_DC:
 862                 /* Yes, we want a DNS */
 863                 break;
 864         }
 865
 866         if (lpcfg_interfaces(task->lp_ctx) && lpcfg_bind_interfaces_only(task->lp_ctx)) {
 867                 load_interface_list(task, task->lp_ctx, &ifaces);
 868
 869                 if (iface_list_count(ifaces) == 0) {
 870                         task_server_terminate(task, "dns: no network interfaces configured", false);
 871                         return;
 872                 }
 873         }
 874
 875         task_server_set_title(task, "task[dns]");
 876
 877         dns = talloc_zero(task, struct dns_server);
 878         if (dns == NULL) {
 879                 task_server_terminate(task, "dns: out of memory", true);
 880                 return;
 881         }
 882
 883         dns->task = task;
 884         /*FIXME: Make this a configurable option */
 885         dns->max_payload = 4096;
 886
 887         dns->server_credentials = cli_credentials_init(dns);
 888         if (!dns->server_credentials) {
 889                 task_server_terminate(task, "Failed to init server credentials\n", true);
 890                 return;
 891         }
 892
 893         dns->samdb = samdb_connect(dns, dns->task->event_ctx, dns->task->lp_ctx,
 894                               system_session(dns->task->lp_ctx), 0);
 895         if (!dns->samdb) {
 896                 task_server_terminate(task, "dns: samdb_connect failed", true);
 897                 return;
 898         }
 899
 900         cli_credentials_set_conf(dns->server_credentials, task->lp_ctx);
 901
 902         hostname_lower = strlower_talloc(dns, lpcfg_netbios_name(task->lp_ctx));
 903         dns_spn = talloc_asprintf(dns, "DNS/%s.%s",
 904                                   hostname_lower,
 905                                   lpcfg_dnsdomain(task->lp_ctx));
 906         TALLOC_FREE(hostname_lower);
 907
 908         ret = dsdb_search_one(dns->samdb, dns, &dns_acc,
 909                               ldb_get_default_basedn(dns->samdb), LDB_SCOPE_SUBTREE,
 910                               attrs_none, 0, "(servicePrincipalName=%s)",
 911                               dns_spn);
 912         if (ret == LDB_SUCCESS) {
 913                 TALLOC_FREE(dns_acc);
 914                 if (!dns_spn) {
 915                         task_server_terminate(task, "dns: talloc_asprintf failed", true);
 916                         return;
 917                 }
 918                 status = cli_credentials_set_stored_principal(dns->server_credentials, task->lp_ctx, dns_spn);
 919                 if (!NT_STATUS_IS_OK(status)) {
 920                         task_server_terminate(task,
 921                                               talloc_asprintf(task, "Failed to obtain server credentials for DNS, "
 922                                                               "despite finding it in the samdb! %s\n",
 923                                                               nt_errstr(status)),
 924                                               true);
 925                         return;
 926                 }
 927         } else {
 928                 TALLOC_FREE(dns_spn);
 929                 status = cli_credentials_set_machine_account(dns->server_credentials, task->lp_ctx);
 930                 if (!NT_STATUS_IS_OK(status)) {
 931                         task_server_terminate(task,
 932                                               talloc_asprintf(task, "Failed to obtain server credentials, perhaps a standalone server?: %s\n",
 933                                                               nt_errstr(status)),
 934                                               true);
 935                         return;
 936                 }
 937         }
 938
 939         dns->tkeys = tkey_store_init(dns, TKEY_BUFFER_SIZE);
 940         if (!dns->tkeys) {
 941                 task_server_terminate(task, "Failed to allocate tkey storage\n", true);
 942                 return;
 943         }
 944
 945         status = dns_server_reload_zones(dns);
 946         if (!NT_STATUS_IS_OK(status)) {
 947                 task_server_terminate(task, "dns: failed to load DNS zones", true);
 948                 return;
 949         }
 950
 951         status = dns_startup_interfaces(dns, ifaces);
 952         if (!NT_STATUS_IS_OK(status)) {
 953                 task_server_terminate(task, "dns failed to setup interfaces", true);
 954                 return;
 955         }
 956
 957         /* Setup the IRPC interface and register handlers */
 958         status = irpc_add_name(task->msg_ctx, "dnssrv");
 959         if (!NT_STATUS_IS_OK(status)) {
 960                 task_server_terminate(task, "dns: failed to register IRPC name", true);
 961                 return;
 962         }
 963
 964         status = IRPC_REGISTER(task->msg_ctx, irpc, DNSSRV_RELOAD_DNS_ZONES,
 965                                dns_reload_zones, dns);
 966         if (!NT_STATUS_IS_OK(status)) {
 967                 task_server_terminate(task, "dns: failed to setup reload handler", true);
 968                 return;
 969         }
 970 }
 971
 972 NTSTATUS server_service_dns_init(void)
 973 {
 974         return register_server_service("dns", dns_task_init);
 975 }