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
  46 /* hold information about one dns socket */
  47 struct dns_socket {
  48         struct dns_server *dns;
  49         struct tsocket_address *local_address;
  50 };
  51
  52 struct dns_udp_socket {
  53         struct dns_socket *dns_socket;
  54         struct tdgram_context *dgram;
  55         struct tevent_queue *send_queue;
  56 };
  57
  58 /*
  59   state of an open tcp connection
  60 */
  61 struct dns_tcp_connection {
  62         /* stream connection we belong to */
  63         struct stream_connection *conn;
  64
  65         /* the dns_server the connection belongs to */
  66         struct dns_socket *dns_socket;
  67
  68         struct tstream_context *tstream;
  69
  70         struct tevent_queue *send_queue;
  71 };
  72
  73 static void dns_tcp_terminate_connection(struct dns_tcp_connection *dnsconn, const char *reason)
  74 {
  75         stream_terminate_connection(dnsconn->conn, reason);
  76 }
  77
  78 static void dns_tcp_recv(struct stream_connection *conn, uint16_t flags)
  79 {
  80         struct dns_tcp_connection *dnsconn = talloc_get_type(conn->private_data,
  81                                                              struct dns_tcp_connection);
  82         /* this should never be triggered! */
  83         dns_tcp_terminate_connection(dnsconn, "dns_tcp_recv: called");
  84 }
  85
  86 static void dns_tcp_send(struct stream_connection *conn, uint16_t flags)
  87 {
  88         struct dns_tcp_connection *dnsconn = talloc_get_type(conn->private_data,
  89                                                              struct dns_tcp_connection);
  90         /* this should never be triggered! */
  91         dns_tcp_terminate_connection(dnsconn, "dns_tcp_send: called");
  92 }
  93
  94 static bool dns_name_match(const char *zone, const char *name, size_t *host_part_len)
  95 {
  96         size_t zl = strlen(zone);
  97         size_t nl = strlen(name);
  98         ssize_t zi, ni;
  99         static const size_t fixup = 'a' - 'A';
 100
 101         if (zl > nl) {
 102                 return false;
 103         }
 104
 105         for (zi = zl, ni = nl; zi >= 0; zi--, ni--) {
 106                 char zc = zone[zi];
 107                 char nc = name[ni];
 108
 109                 /* convert to lower case */
 110                 if (zc >= 'A' && zc <= 'Z') {
 111                         zc += fixup;
 112                 }
 113                 if (nc >= 'A' && nc <= 'Z') {
 114                         nc += fixup;
 115                 }
 116
 117                 if (zc != nc) {
 118                         return false;
 119                 }
 120         }
 121
 122         if (ni >= 0) {
 123                 if (name[ni] != '.') {
 124                         return false;
 125                 }
 126
 127                 ni--;
 128         }
 129
 130         *host_part_len = ni+1;
 131
 132         return true;
 133 }
 134
 135 static NTSTATUS dns_name2dn(struct dns_server *dns,
 136                             TALLOC_CTX *mem_ctx,
 137                             const char *name,
 138                             struct ldb_dn **_dn)
 139 {
 140         struct ldb_dn *base;
 141         struct ldb_dn *dn;
 142         const struct dns_server_zone *z;
 143         size_t host_part_len = 0;
 144
 145         if (name == NULL) {
 146                 return NT_STATUS_INVALID_PARAMETER;
 147         }
 148
 149         /*TODO: Check if 'name' is a valid DNS name */
 150
 151         if (strcmp(name, "") == 0) {
 152                 base = ldb_get_default_basedn(dns->samdb);
 153                 dn = ldb_dn_copy(mem_ctx, base);
 154                 ldb_dn_add_child_fmt(dn, "DC=@,DC=RootDNSServers,CN=MicrosoftDNS,CN=System");
 155                 *_dn = dn;
 156                 return NT_STATUS_OK;
 157         }
 158
 159         for (z = dns->zones; z != NULL; z = z->next) {
 160                 bool match;
 161
 162                 match = dns_name_match(z->name, name, &host_part_len);
 163                 if (match) {
 164                         break;
 165                 }
 166         }
 167
 168         if (z == NULL) {
 169                 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 170         }
 171
 172         if (host_part_len == 0) {
 173                 dn = ldb_dn_copy(mem_ctx, z->dn);
 174                 ldb_dn_add_child_fmt(dn, "DC=@");
 175                 *_dn = dn;
 176                 return NT_STATUS_OK;
 177         }
 178
 179         dn = ldb_dn_copy(mem_ctx, z->dn);
 180         ldb_dn_add_child_fmt(dn, "DC=%*.*s", (int)host_part_len, (int)host_part_len, name);
 181         *_dn = dn;
 182         return NT_STATUS_OK;
 183 }
 184
 185 static NTSTATUS handle_question(struct dns_server *dns,
 186                                 TALLOC_CTX *mem_ctx,
 187                                 const struct dns_name_question *question,
 188                                 struct dns_res_rec **answers, uint16_t *ancount)
 189 {
 190         struct dns_res_rec *ans;
 191         struct ldb_dn *dn = NULL;
 192         NTSTATUS status;
 193         static const char * const attrs[] = { "dnsRecord", NULL};
 194         int ret;
 195         uint16_t ai = *ancount;
 196         uint16_t ri;
 197         struct ldb_message *msg = NULL;
 198         struct dnsp_DnssrvRpcRecord *recs;
 199         struct ldb_message_element *el;
 200
 201         status = dns_name2dn(dns, mem_ctx, question->name, &dn);
 202         NT_STATUS_NOT_OK_RETURN(status);
 203
 204         ret = dsdb_search_one(dns->samdb, mem_ctx, &msg, dn,
 205                               LDB_SCOPE_BASE, attrs, 0, "%s", "(objectClass=dnsNode)");
 206         if (ret != LDB_SUCCESS) {
 207                 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 208         }
 209
 210         el = ldb_msg_find_element(msg, attrs[0]);
 211         if (el == NULL) {
 212                 return NT_STATUS_OBJECT_NAME_NOT_FOUND;
 213         }
 214
 215         recs = talloc_array(mem_ctx, struct dnsp_DnssrvRpcRecord, el->num_values);
 216         for (ri = 0; ri < el->num_values; ri++) {
 217                 struct ldb_val *v = &el->values[ri];
 218                 enum ndr_err_code ndr_err;
 219
 220                 ndr_err = ndr_pull_struct_blob(v, recs, &recs[ri],
 221                                 (ndr_pull_flags_fn_t)ndr_pull_dnsp_DnssrvRpcRecord);
 222                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 223                         DEBUG(0, ("Failed to grab dnsp_DnssrvRpcRecord\n"));
 224                         return NT_STATUS_INTERNAL_DB_CORRUPTION;
 225                 }
 226         }
 227
 228         ans = talloc_realloc(mem_ctx, *answers, struct dns_res_rec,
 229                              ai + el->num_values);
 230         NT_STATUS_HAVE_NO_MEMORY(ans);
 231
 232         switch (question->question_type) {
 233         case DNS_QTYPE_A:
 234                 for (ri = 0; ri < el->num_values; ri++) {
 235                         if (recs[ri].wType != question->question_type) {
 236                                 continue;
 237                         }
 238
 239                         ZERO_STRUCT(ans[ai]);
 240                         ans[ai].name = talloc_strdup(ans, question->name);
 241                         ans[ai].rr_type = DNS_QTYPE_A;
 242                         ans[ai].rr_class = DNS_QCLASS_IP;
 243                         ans[ai].ttl = recs[ri].dwTtlSeconds;
 244                         ans[ai].rdata.ipv4_record = talloc_strdup(ans, recs[ri].data.ipv4);
 245                         ai++;
 246                 }
 247                 break;
 248         case DNS_QTYPE_AAAA:
 249                 for (ri = 0; ri < el->num_values; ri++) {
 250                         if (recs[ri].wType != question->question_type) {
 251                                 continue;
 252                         }
 253
 254                         ZERO_STRUCT(ans[ai]);
 255                         ans[ai].name = talloc_strdup(ans, question->name);
 256                         ans[ai].rr_type = DNS_QTYPE_AAAA;
 257                         ans[ai].rr_class = DNS_QCLASS_IP;
 258                         ans[ai].ttl = recs[ri].dwTtlSeconds;
 259                         ans[ai].rdata.ipv6_record = recs[ri].data.ipv6;
 260                         ai++;
 261                 }
 262                 break;
 263         case DNS_QTYPE_NS:
 264                 for (ri = 0; ri < el->num_values; ri++) {
 265                         if (recs[ri].wType != question->question_type) {
 266                                 continue;
 267                         }
 268
 269                         ZERO_STRUCT(ans[ai]);
 270                         ans[ai].name = question->name;
 271                         ans[ai].rr_type = DNS_QTYPE_NS;
 272                         ans[ai].rr_class = DNS_QCLASS_IP;
 273                         ans[ai].ttl = recs[ri].dwTtlSeconds;
 274                         ans[ai].rdata.ns_record = recs[ri].data.ns;
 275                         ai++;
 276                 }
 277                 break;
 278         default:
 279                 return NT_STATUS_NOT_IMPLEMENTED;
 280         }
 281
 282         *ancount = ai;
 283         *answers = ans;
 284
 285         return NT_STATUS_OK;
 286
 287 }
 288
 289 static NTSTATUS compute_reply(struct dns_server *dns,
 290                               TALLOC_CTX *mem_ctx,
 291                               struct dns_name_packet *in,
 292                               struct dns_res_rec **answers,    uint16_t *ancount,
 293                               struct dns_res_rec **nsrecs,     uint16_t *nscount,
 294                               struct dns_res_rec **additional, uint16_t *arcount)
 295 {
 296         uint16_t num_answers=0;
 297         struct dns_res_rec *ans=NULL;
 298         int i;
 299         NTSTATUS status;
 300
 301         ans = talloc_array(mem_ctx, struct dns_res_rec, 0);
 302         if (answers == NULL) return NT_STATUS_NO_MEMORY;
 303
 304         for (i = 0; i < in->qdcount; ++i) {
 305                 status = handle_question(dns, mem_ctx, &in->questions[i], &ans, &num_answers);
 306                 NT_STATUS_NOT_OK_RETURN(status);
 307         }
 308
 309         *answers = ans;
 310         *ancount = num_answers;
 311
 312         /*FIXME: Do something for these */
 313         *nsrecs  = NULL;
 314         *nscount = 0;
 315
 316         *additional = NULL;
 317         *arcount    = 0;
 318
 319         return NT_STATUS_OK;
 320 }
 321
 322 static NTSTATUS dns_process(struct dns_server *dns,
 323                             TALLOC_CTX *mem_ctx,
 324                             DATA_BLOB *in,
 325                             DATA_BLOB *out)
 326 {
 327         enum ndr_err_code ndr_err;
 328         NTSTATUS ret;
 329         struct dns_name_packet *in_packet = talloc_zero(mem_ctx, struct dns_name_packet);
 330         struct dns_name_packet *out_packet = talloc_zero(mem_ctx, struct dns_name_packet);
 331         struct dns_res_rec *answers, *nsrecs, *additional;
 332         uint16_t num_answers, num_nsrecs, num_additional;
 333
 334         if (in_packet == NULL) return NT_STATUS_INVALID_PARAMETER;
 335
 336         dump_data(2, in->data, in->length);
 337
 338         ndr_err = ndr_pull_struct_blob(in, in_packet, in_packet,
 339                         (ndr_pull_flags_fn_t)ndr_pull_dns_name_packet);
 340         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 341                 TALLOC_FREE(in_packet);
 342                 DEBUG(0, ("Failed to parse packet %d!\n", ndr_err));
 343                 return NT_STATUS_COULD_NOT_INTERPRET;
 344         }
 345
 346         NDR_PRINT_DEBUG(dns_name_packet, in_packet);
 347         out_packet->id = in_packet->id;
 348         out_packet->operation = DNS_FLAG_REPLY | DNS_FLAG_AUTHORITATIVE |
 349                                 DNS_FLAG_RECURSION_DESIRED | DNS_FLAG_RECURSION_AVAIL;
 350
 351         out_packet->qdcount = in_packet->qdcount;
 352         out_packet->questions = in_packet->questions;
 353
 354         out_packet->ancount = 0;
 355         out_packet->answers = NULL;
 356
 357         out_packet->nscount = 0;
 358         out_packet->nsrecs  = NULL;
 359
 360         out_packet->arcount = 0;
 361         out_packet->additional = NULL;
 362
 363         ret = compute_reply(dns, out_packet, in_packet, &answers, &num_answers,
 364                             &nsrecs, &num_nsrecs, &additional, &num_additional);
 365
 366         if (NT_STATUS_IS_OK(ret)) {
 367                 out_packet->ancount = num_answers;
 368                 out_packet->answers = answers;
 369
 370                 out_packet->nscount = num_nsrecs;
 371                 out_packet->nsrecs  = nsrecs;
 372
 373                 out_packet->arcount = num_additional;
 374                 out_packet->additional = additional;
 375         }
 376
 377         NDR_PRINT_DEBUG(dns_name_packet, out_packet);
 378         ndr_err = ndr_push_struct_blob(out, out_packet, out_packet,
 379                         (ndr_push_flags_fn_t)ndr_push_dns_name_packet);
 380         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 381                 TALLOC_FREE(in_packet);
 382                 TALLOC_FREE(out_packet);
 383                 DEBUG(0, ("Failed to push packet %d!\n", ndr_err));
 384                 return NT_STATUS_INTERNAL_ERROR;
 385         }
 386
 387         dump_data(2, out->data, out->length);
 388         return NT_STATUS_OK;
 389 }
 390
 391 struct dns_tcp_call {
 392         struct dns_tcp_connection *dns_conn;
 393         DATA_BLOB in;
 394         DATA_BLOB out;
 395         uint8_t out_hdr[4];
 396         struct iovec out_iov[2];
 397 };
 398
 399 static void dns_tcp_call_writev_done(struct tevent_req *subreq);
 400
 401 static void dns_tcp_call_loop(struct tevent_req *subreq)
 402 {
 403         struct dns_tcp_connection *dns_conn = tevent_req_callback_data(subreq,
 404                                       struct dns_tcp_connection);
 405         struct dns_tcp_call *call;
 406         NTSTATUS status;
 407
 408         call = talloc(dns_conn, struct dns_tcp_call);
 409         if (call == NULL) {
 410                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 411                                 "no memory for dns_tcp_call");
 412                 return;
 413         }
 414         call->dns_conn = dns_conn;
 415
 416         status = tstream_read_pdu_blob_recv(subreq,
 417                                             call,
 418                                             &call->in);
 419         TALLOC_FREE(subreq);
 420         if (!NT_STATUS_IS_OK(status)) {
 421                 const char *reason;
 422
 423                 reason = talloc_asprintf(call, "dns_tcp_call_loop: "
 424                                          "tstream_read_pdu_blob_recv() - %s",
 425                                          nt_errstr(status));
 426                 if (!reason) {
 427                         reason = nt_errstr(status);
 428                 }
 429
 430                 dns_tcp_terminate_connection(dns_conn, reason);
 431                 return;
 432         }
 433
 434         DEBUG(10,("Received krb5 TCP packet of length %lu from %s\n",
 435                  (long) call->in.length,
 436                  tsocket_address_string(dns_conn->conn->remote_address, call)));
 437
 438         /* skip length header */
 439         call->in.data +=4;
 440         call->in.length -= 4;
 441
 442         /* Call dns */
 443         status = dns_process(dns_conn->dns_socket->dns, call, &call->in, &call->out);
 444         if (!NT_STATUS_IS_OK(status)) {
 445                 DEBUG(0, ("dns_process returned %s\n", nt_errstr(status)));
 446                 dns_tcp_terminate_connection(dns_conn,
 447                                 "dns_tcp_call_loop: process function failed");
 448                 return;
 449         }
 450
 451         /* First add the length of the out buffer */
 452         RSIVAL(call->out_hdr, 0, call->out.length);
 453         call->out_iov[0].iov_base = (char *) call->out_hdr;
 454         call->out_iov[0].iov_len = 4;
 455
 456         call->out_iov[1].iov_base = (char *) call->out.data;
 457         call->out_iov[1].iov_len = call->out.length;
 458
 459         subreq = tstream_writev_queue_send(call,
 460                                            dns_conn->conn->event.ctx,
 461                                            dns_conn->tstream,
 462                                            dns_conn->send_queue,
 463                                            call->out_iov, 2);
 464         if (subreq == NULL) {
 465                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 466                                 "no memory for tstream_writev_queue_send");
 467                 return;
 468         }
 469         tevent_req_set_callback(subreq, dns_tcp_call_writev_done, call);
 470
 471         /*
 472          * The krb5 tcp pdu's has the length as 4 byte (initial_read_size),
 473          * packet_full_request_u32 provides the pdu length then.
 474          */
 475         subreq = tstream_read_pdu_blob_send(dns_conn,
 476                                             dns_conn->conn->event.ctx,
 477                                             dns_conn->tstream,
 478                                             4, /* initial_read_size */
 479                                             packet_full_request_u32,
 480                                             dns_conn);
 481         if (subreq == NULL) {
 482                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 483                                 "no memory for tstream_read_pdu_blob_send");
 484                 return;
 485         }
 486         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 487 }
 488
 489 static void dns_tcp_call_writev_done(struct tevent_req *subreq)
 490 {
 491         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 492                         struct dns_tcp_call);
 493         int sys_errno;
 494         int rc;
 495
 496         rc = tstream_writev_queue_recv(subreq, &sys_errno);
 497         TALLOC_FREE(subreq);
 498         if (rc == -1) {
 499                 const char *reason;
 500
 501                 reason = talloc_asprintf(call, "dns_tcp_call_writev_done: "
 502                                          "tstream_writev_queue_recv() - %d:%s",
 503                                          sys_errno, strerror(sys_errno));
 504                 if (!reason) {
 505                         reason = "dns_tcp_call_writev_done: tstream_writev_queue_recv() failed";
 506                 }
 507
 508                 dns_tcp_terminate_connection(call->dns_conn, reason);
 509                 return;
 510         }
 511
 512         /* We don't care about errors */
 513
 514         talloc_free(call);
 515 }
 516
 517 /*
 518   called when we get a new connection
 519 */
 520 static void dns_tcp_accept(struct stream_connection *conn)
 521 {
 522         struct dns_socket *dns_socket;
 523         struct dns_tcp_connection *dns_conn;
 524         struct tevent_req *subreq;
 525         int rc;
 526
 527         dns_conn = talloc_zero(conn, struct dns_tcp_connection);
 528         if (dns_conn == NULL) {
 529                 stream_terminate_connection(conn,
 530                                 "dns_tcp_accept: out of memory");
 531                 return;
 532         }
 533
 534         dns_conn->send_queue = tevent_queue_create(conn, "dns_tcp_accept");
 535         if (dns_conn->send_queue == NULL) {
 536                 stream_terminate_connection(conn,
 537                                 "dns_tcp_accept: out of memory");
 538                 return;
 539         }
 540
 541         dns_socket = talloc_get_type(conn->private_data, struct dns_socket);
 542
 543         TALLOC_FREE(conn->event.fde);
 544
 545         rc = tstream_bsd_existing_socket(dns_conn,
 546                         socket_get_fd(conn->socket),
 547                         &dns_conn->tstream);
 548         if (rc < 0) {
 549                 stream_terminate_connection(conn,
 550                                 "dns_tcp_accept: out of memory");
 551                 return;
 552         }
 553
 554         dns_conn->conn = conn;
 555         dns_conn->dns_socket = dns_socket;
 556         conn->private_data = dns_conn;
 557
 558         /*
 559          * The krb5 tcp pdu's has the length as 4 byte (initial_read_size),
 560          * packet_full_request_u32 provides the pdu length then.
 561          */
 562         subreq = tstream_read_pdu_blob_send(dns_conn,
 563                                             dns_conn->conn->event.ctx,
 564                                             dns_conn->tstream,
 565                                             4, /* initial_read_size */
 566                                             packet_full_request_u32,
 567                                             dns_conn);
 568         if (subreq == NULL) {
 569                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_accept: "
 570                                 "no memory for tstream_read_pdu_blob_send");
 571                 return;
 572         }
 573         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 574 }
 575
 576 static const struct stream_server_ops dns_tcp_stream_ops = {
 577         .name                   = "dns_tcp",
 578         .accept_connection      = dns_tcp_accept,
 579         .recv_handler           = dns_tcp_recv,
 580         .send_handler           = dns_tcp_send
 581 };
 582
 583 struct dns_udp_call {
 584         struct tsocket_address *src;
 585         DATA_BLOB in;
 586         DATA_BLOB out;
 587 };
 588
 589 static void dns_udp_call_sendto_done(struct tevent_req *subreq);
 590
 591 static void dns_udp_call_loop(struct tevent_req *subreq)
 592 {
 593         struct dns_udp_socket *sock = tevent_req_callback_data(subreq,
 594                                       struct dns_udp_socket);
 595         struct dns_udp_call *call;
 596         uint8_t *buf;
 597         ssize_t len;
 598         int sys_errno;
 599         NTSTATUS status;
 600
 601         call = talloc(sock, struct dns_udp_call);
 602         if (call == NULL) {
 603                 talloc_free(call);
 604                 goto done;
 605         }
 606
 607         len = tdgram_recvfrom_recv(subreq, &sys_errno,
 608                                    call, &buf, &call->src);
 609         TALLOC_FREE(subreq);
 610         if (len == -1) {
 611                 talloc_free(call);
 612                 goto done;
 613         }
 614
 615         call->in.data = buf;
 616         call->in.length = len;
 617
 618         DEBUG(10,("Received krb5 UDP packet of length %lu from %s\n",
 619                  (long)call->in.length,
 620                  tsocket_address_string(call->src, call)));
 621
 622         /* Call krb5 */
 623         status = dns_process(sock->dns_socket->dns, call, &call->in, &call->out);
 624         if (!NT_STATUS_IS_OK(status)) {
 625                 talloc_free(call);
 626                 DEBUG(0, ("dns_process returned %s\n", nt_errstr(status)));
 627                 goto done;
 628         }
 629
 630         subreq = tdgram_sendto_queue_send(call,
 631                                           sock->dns_socket->dns->task->event_ctx,
 632                                           sock->dgram,
 633                                           sock->send_queue,
 634                                           call->out.data,
 635                                           call->out.length,
 636                                           call->src);
 637         if (subreq == NULL) {
 638                 talloc_free(call);
 639                 goto done;
 640         }
 641         tevent_req_set_callback(subreq, dns_udp_call_sendto_done, call);
 642
 643 done:
 644         subreq = tdgram_recvfrom_send(sock,
 645                                       sock->dns_socket->dns->task->event_ctx,
 646                                       sock->dgram);
 647         if (subreq == NULL) {
 648                 task_server_terminate(sock->dns_socket->dns->task,
 649                                       "no memory for tdgram_recvfrom_send",
 650                                       true);
 651                 return;
 652         }
 653         tevent_req_set_callback(subreq, dns_udp_call_loop, sock);
 654 }
 655
 656 static void dns_udp_call_sendto_done(struct tevent_req *subreq)
 657 {
 658         struct dns_udp_call *call = tevent_req_callback_data(subreq,
 659                                        struct dns_udp_call);
 660         ssize_t ret;
 661         int sys_errno;
 662
 663         ret = tdgram_sendto_queue_recv(subreq, &sys_errno);
 664
 665         /* We don't care about errors */
 666
 667         talloc_free(call);
 668 }
 669
 670 /*
 671   start listening on the given address
 672 */
 673 static NTSTATUS dns_add_socket(struct dns_server *dns,
 674                                const struct model_ops *model_ops,
 675                                const char *name,
 676                                const char *address,
 677                                uint16_t port)
 678 {
 679         struct dns_socket *dns_socket;
 680         struct dns_udp_socket *dns_udp_socket;
 681         struct tevent_req *udpsubreq;
 682         NTSTATUS status;
 683         int ret;
 684
 685         dns_socket = talloc(dns, struct dns_socket);
 686         NT_STATUS_HAVE_NO_MEMORY(dns_socket);
 687
 688         dns_socket->dns = dns;
 689
 690         ret = tsocket_address_inet_from_strings(dns_socket, "ip",
 691                                                 address, port,
 692                                                 &dns_socket->local_address);
 693         if (ret != 0) {
 694                 status = map_nt_error_from_unix(errno);
 695                 return status;
 696         }
 697
 698         status = stream_setup_socket(dns->task->event_ctx,
 699                                      dns->task->lp_ctx,
 700                                      model_ops,
 701                                      &dns_tcp_stream_ops,
 702                                      "ip", address, &port,
 703                                      lpcfg_socket_options(dns->task->lp_ctx),
 704                                      dns_socket);
 705         if (!NT_STATUS_IS_OK(status)) {
 706                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 707                          address, port, nt_errstr(status)));
 708                 talloc_free(dns_socket);
 709                 return status;
 710         }
 711
 712         dns_udp_socket = talloc(dns_socket, struct dns_udp_socket);
 713         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket);
 714
 715         dns_udp_socket->dns_socket = dns_socket;
 716
 717         ret = tdgram_inet_udp_socket(dns_socket->local_address,
 718                                      NULL,
 719                                      dns_udp_socket,
 720                                      &dns_udp_socket->dgram);
 721         if (ret != 0) {
 722                 status = map_nt_error_from_unix(errno);
 723                 DEBUG(0,("Failed to bind to %s:%u UDP - %s\n",
 724                          address, port, nt_errstr(status)));
 725                 return status;
 726         }
 727
 728         dns_udp_socket->send_queue = tevent_queue_create(dns_udp_socket,
 729                                                          "dns_udp_send_queue");
 730         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket->send_queue);
 731
 732         udpsubreq = tdgram_recvfrom_send(dns_udp_socket,
 733                                          dns->task->event_ctx,
 734                                          dns_udp_socket->dgram);
 735         NT_STATUS_HAVE_NO_MEMORY(udpsubreq);
 736         tevent_req_set_callback(udpsubreq, dns_udp_call_loop, dns_udp_socket);
 737
 738         return NT_STATUS_OK;
 739 }
 740
 741 /*
 742   setup our listening sockets on the configured network interfaces
 743 */
 744 static NTSTATUS dns_startup_interfaces(struct dns_server *dns, struct loadparm_context *lp_ctx,
 745                                        struct interface *ifaces)
 746 {
 747         const struct model_ops *model_ops;
 748         int num_interfaces;
 749         TALLOC_CTX *tmp_ctx = talloc_new(dns);
 750         NTSTATUS status;
 751         int i;
 752
 753         /* within the dns task we want to be a single process, so
 754            ask for the single process model ops and pass these to the
 755            stream_setup_socket() call. */
 756         model_ops = process_model_startup(dns->task->event_ctx, "single");
 757         if (!model_ops) {
 758                 DEBUG(0,("Can't find 'single' process model_ops\n"));
 759                 return NT_STATUS_INTERNAL_ERROR;
 760         }
 761
 762         num_interfaces = iface_count(ifaces);
 763
 764         for (i=0; i<num_interfaces; i++) {
 765                 const char *address = talloc_strdup(tmp_ctx, iface_n_ip(ifaces, i));
 766
 767                 status = dns_add_socket(dns, model_ops, "dns", address, DNS_SERVICE_PORT);
 768                 NT_STATUS_NOT_OK_RETURN(status);
 769         }
 770
 771         talloc_free(tmp_ctx);
 772
 773         return NT_STATUS_OK;
 774 }
 775
 776 static int dns_server_sort_zones(struct ldb_message **m1, struct ldb_message **m2)
 777 {
 778         const char *n1, *n2;
 779         size_t l1, l2;
 780
 781         n1 = ldb_msg_find_attr_as_string(*m1, "name", NULL);
 782         n2 = ldb_msg_find_attr_as_string(*m2, "name", NULL);
 783
 784         l1 = strlen(n1);
 785         l2 = strlen(n2);
 786
 787         /* If the string lengths are not equal just sort by length */
 788         if (l1 != l2) {
 789                 /* If m1 is the larger zone name, return it first */
 790                 return l2 - l1;
 791         }
 792
 793         /*TODO: We need to compare DNs here, we want the DomainDNSZones first */
 794         return 0;
 795 }
 796
 797 static void dns_task_init(struct task_server *task)
 798 {
 799         struct dns_server *dns;
 800         NTSTATUS status;
 801         struct interface *ifaces;
 802         int ret;
 803         struct ldb_result *res;
 804         struct ldb_dn *rootdn;
 805         static const char * const attrs[] = { "name", NULL};
 806         int i;
 807
 808
 809         switch (lpcfg_server_role(task->lp_ctx)) {
 810         case ROLE_STANDALONE:
 811                 task_server_terminate(task, "dns: no DNS required in standalone configuration", false);
 812                 return;
 813         case ROLE_DOMAIN_MEMBER:
 814                 task_server_terminate(task, "dns: no DNS required in member server configuration", false);
 815                 return;
 816         case ROLE_DOMAIN_CONTROLLER:
 817                 /* Yes, we want a DNS */
 818                 break;
 819         }
 820
 821         load_interfaces(task, lpcfg_interfaces(task->lp_ctx), &ifaces);
 822
 823         if (iface_count(ifaces) == 0) {
 824                 task_server_terminate(task, "dns: no network interfaces configured", false);
 825                 return;
 826         }
 827
 828         task_server_set_title(task, "task[dns]");
 829
 830         dns = talloc_zero(task, struct dns_server);
 831         if (dns == NULL) {
 832                 task_server_terminate(task, "dns: out of memory", true);
 833                 return;
 834         }
 835
 836         dns->task = task;
 837
 838         dns->samdb = samdb_connect(dns, dns->task->event_ctx, dns->task->lp_ctx,
 839                               system_session(dns->task->lp_ctx), 0);
 840         if (!dns->samdb) {
 841                 task_server_terminate(task, "dns: samdb_connect failed", true);
 842                 return;
 843         }
 844
 845         rootdn = ldb_dn_new(dns, dns->samdb, "");
 846         if (rootdn == NULL) {
 847                 task_server_terminate(task, "dns: out of memory", true);
 848                 return;
 849         }
 850
 851         // TODO: this search does not work against windows
 852         ret = dsdb_search(dns->samdb, dns, &res, rootdn, LDB_SCOPE_SUBTREE,
 853                           attrs, DSDB_SEARCH_SEARCH_ALL_PARTITIONS, "(objectClass=dnsZone)");
 854         if (ret != LDB_SUCCESS) {
 855                 task_server_terminate(task,
 856                                       "dns: failed to look up root DNS zones",
 857                                       true);
 858                 return;
 859         }
 860
 861         TYPESAFE_QSORT(res->msgs, res->count, dns_server_sort_zones);
 862
 863         for (i=0; i < res->count; i++) {
 864                 struct dns_server_zone *z;
 865
 866                 z = talloc_zero(dns, struct dns_server_zone);
 867                 if (z == NULL) {
 868                 }
 869
 870                 z->name = ldb_msg_find_attr_as_string(res->msgs[i], "name", NULL);
 871                 z->dn = talloc_move(z, &res->msgs[i]->dn);
 872
 873                 DLIST_ADD_END(dns->zones, z, NULL);
 874         }
 875
 876         status = dns_startup_interfaces(dns, task->lp_ctx, ifaces);
 877         if (!NT_STATUS_IS_OK(status)) {
 878                 task_server_terminate(task, "dns failed to setup interfaces", true);
 879                 return;
 880         }
 881 }
 882
 883 NTSTATUS server_service_dns_init(void)
 884 {
 885         return register_server_service("dns", dns_task_init);
 886 }