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         case DNS_QTYPE_SRV:
 279                 for (ri = 0; ri < el->num_values; ri++) {
 280                         if (recs[ri].wType != question->question_type) {
 281                                 continue;
 282                         }
 283
 284                         ZERO_STRUCT(ans[ai]);
 285                         ans[ai].name = question->name;
 286                         ans[ai].rr_type = DNS_QTYPE_SRV;
 287                         ans[ai].rr_class = DNS_QCLASS_IP;
 288                         ans[ai].ttl = recs[ri].dwTtlSeconds;
 289                         ans[ai].rdata.srv_record.priority = recs[ri].data.srv.wPriority;
 290                         ans[ai].rdata.srv_record.weight = recs[ri].data.srv.wWeight;
 291                         ans[ai].rdata.srv_record.port = recs[ri].data.srv.wPort;
 292                         ans[ai].rdata.srv_record.target = recs[ri].data.srv.nameTarget;
 293                         ai++;
 294                 }
 295                 break;
 296         case DNS_QTYPE_SOA:
 297                 for (ri = 0; ri < el->num_values; ri++) {
 298                         if (recs[ri].wType != question->question_type) {
 299                                 continue;
 300                         }
 301
 302                         ZERO_STRUCT(ans[ai]);
 303                         ans[ai].name = question->name;
 304                         ans[ai].rr_type = DNS_QTYPE_SOA;
 305                         ans[ai].rr_class = DNS_QCLASS_IP;
 306                         ans[ai].ttl = recs[ri].dwTtlSeconds;
 307                         ans[ai].rdata.soa_record.mname  = recs[ri].data.soa.mname;
 308                         ans[ai].rdata.soa_record.rname  = recs[ri].data.soa.rname;
 309                         ans[ai].rdata.soa_record.serial = recs[ri].data.soa.serial;
 310                         ans[ai].rdata.soa_record.refresh= recs[ri].data.soa.refresh;
 311                         ans[ai].rdata.soa_record.retry  = recs[ri].data.soa.retry;
 312                         ans[ai].rdata.soa_record.expire = recs[ri].data.soa.expire;
 313                         ans[ai].rdata.soa_record.minimum= recs[ri].data.soa.minimum;
 314                         ai++;
 315                 }
 316                 break;
 317         default:
 318                 return NT_STATUS_NOT_IMPLEMENTED;
 319         }
 320
 321         *ancount = ai;
 322         *answers = ans;
 323
 324         return NT_STATUS_OK;
 325
 326 }
 327
 328 static NTSTATUS compute_reply(struct dns_server *dns,
 329                               TALLOC_CTX *mem_ctx,
 330                               struct dns_name_packet *in,
 331                               struct dns_res_rec **answers,    uint16_t *ancount,
 332                               struct dns_res_rec **nsrecs,     uint16_t *nscount,
 333                               struct dns_res_rec **additional, uint16_t *arcount)
 334 {
 335         uint16_t num_answers=0;
 336         struct dns_res_rec *ans=NULL;
 337         int i;
 338         NTSTATUS status;
 339
 340         ans = talloc_array(mem_ctx, struct dns_res_rec, 0);
 341         if (answers == NULL) return NT_STATUS_NO_MEMORY;
 342
 343         for (i = 0; i < in->qdcount; ++i) {
 344                 status = handle_question(dns, mem_ctx, &in->questions[i], &ans, &num_answers);
 345                 NT_STATUS_NOT_OK_RETURN(status);
 346         }
 347
 348         *answers = ans;
 349         *ancount = num_answers;
 350
 351         /*FIXME: Do something for these */
 352         *nsrecs  = NULL;
 353         *nscount = 0;
 354
 355         *additional = NULL;
 356         *arcount    = 0;
 357
 358         return NT_STATUS_OK;
 359 }
 360
 361 static NTSTATUS dns_process(struct dns_server *dns,
 362                             TALLOC_CTX *mem_ctx,
 363                             DATA_BLOB *in,
 364                             DATA_BLOB *out)
 365 {
 366         enum ndr_err_code ndr_err;
 367         NTSTATUS ret;
 368         struct dns_name_packet *in_packet = talloc_zero(mem_ctx, struct dns_name_packet);
 369         struct dns_name_packet *out_packet = talloc_zero(mem_ctx, struct dns_name_packet);
 370         struct dns_res_rec *answers, *nsrecs, *additional;
 371         uint16_t num_answers, num_nsrecs, num_additional;
 372
 373         if (in_packet == NULL) return NT_STATUS_INVALID_PARAMETER;
 374
 375         dump_data(2, in->data, in->length);
 376
 377         ndr_err = ndr_pull_struct_blob(in, in_packet, in_packet,
 378                         (ndr_pull_flags_fn_t)ndr_pull_dns_name_packet);
 379         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 380                 TALLOC_FREE(in_packet);
 381                 DEBUG(0, ("Failed to parse packet %d!\n", ndr_err));
 382                 return NT_STATUS_COULD_NOT_INTERPRET;
 383         }
 384
 385         NDR_PRINT_DEBUG(dns_name_packet, in_packet);
 386         out_packet->id = in_packet->id;
 387         out_packet->operation = DNS_FLAG_REPLY | DNS_FLAG_AUTHORITATIVE |
 388                                 DNS_FLAG_RECURSION_DESIRED | DNS_FLAG_RECURSION_AVAIL;
 389
 390         out_packet->qdcount = in_packet->qdcount;
 391         out_packet->questions = in_packet->questions;
 392
 393         out_packet->ancount = 0;
 394         out_packet->answers = NULL;
 395
 396         out_packet->nscount = 0;
 397         out_packet->nsrecs  = NULL;
 398
 399         out_packet->arcount = 0;
 400         out_packet->additional = NULL;
 401
 402         ret = compute_reply(dns, out_packet, in_packet, &answers, &num_answers,
 403                             &nsrecs, &num_nsrecs, &additional, &num_additional);
 404
 405         if (NT_STATUS_IS_OK(ret)) {
 406                 out_packet->ancount = num_answers;
 407                 out_packet->answers = answers;
 408
 409                 out_packet->nscount = num_nsrecs;
 410                 out_packet->nsrecs  = nsrecs;
 411
 412                 out_packet->arcount = num_additional;
 413                 out_packet->additional = additional;
 414         }
 415
 416         NDR_PRINT_DEBUG(dns_name_packet, out_packet);
 417         ndr_err = ndr_push_struct_blob(out, out_packet, out_packet,
 418                         (ndr_push_flags_fn_t)ndr_push_dns_name_packet);
 419         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 420                 TALLOC_FREE(in_packet);
 421                 TALLOC_FREE(out_packet);
 422                 DEBUG(0, ("Failed to push packet %d!\n", ndr_err));
 423                 return NT_STATUS_INTERNAL_ERROR;
 424         }
 425
 426         dump_data(2, out->data, out->length);
 427         return NT_STATUS_OK;
 428 }
 429
 430 struct dns_tcp_call {
 431         struct dns_tcp_connection *dns_conn;
 432         DATA_BLOB in;
 433         DATA_BLOB out;
 434         uint8_t out_hdr[4];
 435         struct iovec out_iov[2];
 436 };
 437
 438 static void dns_tcp_call_writev_done(struct tevent_req *subreq);
 439
 440 static void dns_tcp_call_loop(struct tevent_req *subreq)
 441 {
 442         struct dns_tcp_connection *dns_conn = tevent_req_callback_data(subreq,
 443                                       struct dns_tcp_connection);
 444         struct dns_tcp_call *call;
 445         NTSTATUS status;
 446
 447         call = talloc(dns_conn, struct dns_tcp_call);
 448         if (call == NULL) {
 449                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 450                                 "no memory for dns_tcp_call");
 451                 return;
 452         }
 453         call->dns_conn = dns_conn;
 454
 455         status = tstream_read_pdu_blob_recv(subreq,
 456                                             call,
 457                                             &call->in);
 458         TALLOC_FREE(subreq);
 459         if (!NT_STATUS_IS_OK(status)) {
 460                 const char *reason;
 461
 462                 reason = talloc_asprintf(call, "dns_tcp_call_loop: "
 463                                          "tstream_read_pdu_blob_recv() - %s",
 464                                          nt_errstr(status));
 465                 if (!reason) {
 466                         reason = nt_errstr(status);
 467                 }
 468
 469                 dns_tcp_terminate_connection(dns_conn, reason);
 470                 return;
 471         }
 472
 473         DEBUG(10,("Received krb5 TCP packet of length %lu from %s\n",
 474                  (long) call->in.length,
 475                  tsocket_address_string(dns_conn->conn->remote_address, call)));
 476
 477         /* skip length header */
 478         call->in.data +=4;
 479         call->in.length -= 4;
 480
 481         /* Call dns */
 482         status = dns_process(dns_conn->dns_socket->dns, call, &call->in, &call->out);
 483         if (!NT_STATUS_IS_OK(status)) {
 484                 DEBUG(0, ("dns_process returned %s\n", nt_errstr(status)));
 485                 dns_tcp_terminate_connection(dns_conn,
 486                                 "dns_tcp_call_loop: process function failed");
 487                 return;
 488         }
 489
 490         /* First add the length of the out buffer */
 491         RSIVAL(call->out_hdr, 0, call->out.length);
 492         call->out_iov[0].iov_base = (char *) call->out_hdr;
 493         call->out_iov[0].iov_len = 4;
 494
 495         call->out_iov[1].iov_base = (char *) call->out.data;
 496         call->out_iov[1].iov_len = call->out.length;
 497
 498         subreq = tstream_writev_queue_send(call,
 499                                            dns_conn->conn->event.ctx,
 500                                            dns_conn->tstream,
 501                                            dns_conn->send_queue,
 502                                            call->out_iov, 2);
 503         if (subreq == NULL) {
 504                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 505                                 "no memory for tstream_writev_queue_send");
 506                 return;
 507         }
 508         tevent_req_set_callback(subreq, dns_tcp_call_writev_done, call);
 509
 510         /*
 511          * The krb5 tcp pdu's has the length as 4 byte (initial_read_size),
 512          * packet_full_request_u32 provides the pdu length then.
 513          */
 514         subreq = tstream_read_pdu_blob_send(dns_conn,
 515                                             dns_conn->conn->event.ctx,
 516                                             dns_conn->tstream,
 517                                             4, /* initial_read_size */
 518                                             packet_full_request_u32,
 519                                             dns_conn);
 520         if (subreq == NULL) {
 521                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_call_loop: "
 522                                 "no memory for tstream_read_pdu_blob_send");
 523                 return;
 524         }
 525         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 526 }
 527
 528 static void dns_tcp_call_writev_done(struct tevent_req *subreq)
 529 {
 530         struct dns_tcp_call *call = tevent_req_callback_data(subreq,
 531                         struct dns_tcp_call);
 532         int sys_errno;
 533         int rc;
 534
 535         rc = tstream_writev_queue_recv(subreq, &sys_errno);
 536         TALLOC_FREE(subreq);
 537         if (rc == -1) {
 538                 const char *reason;
 539
 540                 reason = talloc_asprintf(call, "dns_tcp_call_writev_done: "
 541                                          "tstream_writev_queue_recv() - %d:%s",
 542                                          sys_errno, strerror(sys_errno));
 543                 if (!reason) {
 544                         reason = "dns_tcp_call_writev_done: tstream_writev_queue_recv() failed";
 545                 }
 546
 547                 dns_tcp_terminate_connection(call->dns_conn, reason);
 548                 return;
 549         }
 550
 551         /* We don't care about errors */
 552
 553         talloc_free(call);
 554 }
 555
 556 /*
 557   called when we get a new connection
 558 */
 559 static void dns_tcp_accept(struct stream_connection *conn)
 560 {
 561         struct dns_socket *dns_socket;
 562         struct dns_tcp_connection *dns_conn;
 563         struct tevent_req *subreq;
 564         int rc;
 565
 566         dns_conn = talloc_zero(conn, struct dns_tcp_connection);
 567         if (dns_conn == NULL) {
 568                 stream_terminate_connection(conn,
 569                                 "dns_tcp_accept: out of memory");
 570                 return;
 571         }
 572
 573         dns_conn->send_queue = tevent_queue_create(conn, "dns_tcp_accept");
 574         if (dns_conn->send_queue == NULL) {
 575                 stream_terminate_connection(conn,
 576                                 "dns_tcp_accept: out of memory");
 577                 return;
 578         }
 579
 580         dns_socket = talloc_get_type(conn->private_data, struct dns_socket);
 581
 582         TALLOC_FREE(conn->event.fde);
 583
 584         rc = tstream_bsd_existing_socket(dns_conn,
 585                         socket_get_fd(conn->socket),
 586                         &dns_conn->tstream);
 587         if (rc < 0) {
 588                 stream_terminate_connection(conn,
 589                                 "dns_tcp_accept: out of memory");
 590                 return;
 591         }
 592
 593         dns_conn->conn = conn;
 594         dns_conn->dns_socket = dns_socket;
 595         conn->private_data = dns_conn;
 596
 597         /*
 598          * The krb5 tcp pdu's has the length as 4 byte (initial_read_size),
 599          * packet_full_request_u32 provides the pdu length then.
 600          */
 601         subreq = tstream_read_pdu_blob_send(dns_conn,
 602                                             dns_conn->conn->event.ctx,
 603                                             dns_conn->tstream,
 604                                             4, /* initial_read_size */
 605                                             packet_full_request_u32,
 606                                             dns_conn);
 607         if (subreq == NULL) {
 608                 dns_tcp_terminate_connection(dns_conn, "dns_tcp_accept: "
 609                                 "no memory for tstream_read_pdu_blob_send");
 610                 return;
 611         }
 612         tevent_req_set_callback(subreq, dns_tcp_call_loop, dns_conn);
 613 }
 614
 615 static const struct stream_server_ops dns_tcp_stream_ops = {
 616         .name                   = "dns_tcp",
 617         .accept_connection      = dns_tcp_accept,
 618         .recv_handler           = dns_tcp_recv,
 619         .send_handler           = dns_tcp_send
 620 };
 621
 622 struct dns_udp_call {
 623         struct tsocket_address *src;
 624         DATA_BLOB in;
 625         DATA_BLOB out;
 626 };
 627
 628 static void dns_udp_call_sendto_done(struct tevent_req *subreq);
 629
 630 static void dns_udp_call_loop(struct tevent_req *subreq)
 631 {
 632         struct dns_udp_socket *sock = tevent_req_callback_data(subreq,
 633                                       struct dns_udp_socket);
 634         struct dns_udp_call *call;
 635         uint8_t *buf;
 636         ssize_t len;
 637         int sys_errno;
 638         NTSTATUS status;
 639
 640         call = talloc(sock, struct dns_udp_call);
 641         if (call == NULL) {
 642                 talloc_free(call);
 643                 goto done;
 644         }
 645
 646         len = tdgram_recvfrom_recv(subreq, &sys_errno,
 647                                    call, &buf, &call->src);
 648         TALLOC_FREE(subreq);
 649         if (len == -1) {
 650                 talloc_free(call);
 651                 goto done;
 652         }
 653
 654         call->in.data = buf;
 655         call->in.length = len;
 656
 657         DEBUG(10,("Received krb5 UDP packet of length %lu from %s\n",
 658                  (long)call->in.length,
 659                  tsocket_address_string(call->src, call)));
 660
 661         /* Call krb5 */
 662         status = dns_process(sock->dns_socket->dns, call, &call->in, &call->out);
 663         if (!NT_STATUS_IS_OK(status)) {
 664                 talloc_free(call);
 665                 DEBUG(0, ("dns_process returned %s\n", nt_errstr(status)));
 666                 goto done;
 667         }
 668
 669         subreq = tdgram_sendto_queue_send(call,
 670                                           sock->dns_socket->dns->task->event_ctx,
 671                                           sock->dgram,
 672                                           sock->send_queue,
 673                                           call->out.data,
 674                                           call->out.length,
 675                                           call->src);
 676         if (subreq == NULL) {
 677                 talloc_free(call);
 678                 goto done;
 679         }
 680         tevent_req_set_callback(subreq, dns_udp_call_sendto_done, call);
 681
 682 done:
 683         subreq = tdgram_recvfrom_send(sock,
 684                                       sock->dns_socket->dns->task->event_ctx,
 685                                       sock->dgram);
 686         if (subreq == NULL) {
 687                 task_server_terminate(sock->dns_socket->dns->task,
 688                                       "no memory for tdgram_recvfrom_send",
 689                                       true);
 690                 return;
 691         }
 692         tevent_req_set_callback(subreq, dns_udp_call_loop, sock);
 693 }
 694
 695 static void dns_udp_call_sendto_done(struct tevent_req *subreq)
 696 {
 697         struct dns_udp_call *call = tevent_req_callback_data(subreq,
 698                                        struct dns_udp_call);
 699         ssize_t ret;
 700         int sys_errno;
 701
 702         ret = tdgram_sendto_queue_recv(subreq, &sys_errno);
 703
 704         /* We don't care about errors */
 705
 706         talloc_free(call);
 707 }
 708
 709 /*
 710   start listening on the given address
 711 */
 712 static NTSTATUS dns_add_socket(struct dns_server *dns,
 713                                const struct model_ops *model_ops,
 714                                const char *name,
 715                                const char *address,
 716                                uint16_t port)
 717 {
 718         struct dns_socket *dns_socket;
 719         struct dns_udp_socket *dns_udp_socket;
 720         struct tevent_req *udpsubreq;
 721         NTSTATUS status;
 722         int ret;
 723
 724         dns_socket = talloc(dns, struct dns_socket);
 725         NT_STATUS_HAVE_NO_MEMORY(dns_socket);
 726
 727         dns_socket->dns = dns;
 728
 729         ret = tsocket_address_inet_from_strings(dns_socket, "ip",
 730                                                 address, port,
 731                                                 &dns_socket->local_address);
 732         if (ret != 0) {
 733                 status = map_nt_error_from_unix(errno);
 734                 return status;
 735         }
 736
 737         status = stream_setup_socket(dns->task->event_ctx,
 738                                      dns->task->lp_ctx,
 739                                      model_ops,
 740                                      &dns_tcp_stream_ops,
 741                                      "ip", address, &port,
 742                                      lpcfg_socket_options(dns->task->lp_ctx),
 743                                      dns_socket);
 744         if (!NT_STATUS_IS_OK(status)) {
 745                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 746                          address, port, nt_errstr(status)));
 747                 talloc_free(dns_socket);
 748                 return status;
 749         }
 750
 751         dns_udp_socket = talloc(dns_socket, struct dns_udp_socket);
 752         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket);
 753
 754         dns_udp_socket->dns_socket = dns_socket;
 755
 756         ret = tdgram_inet_udp_socket(dns_socket->local_address,
 757                                      NULL,
 758                                      dns_udp_socket,
 759                                      &dns_udp_socket->dgram);
 760         if (ret != 0) {
 761                 status = map_nt_error_from_unix(errno);
 762                 DEBUG(0,("Failed to bind to %s:%u UDP - %s\n",
 763                          address, port, nt_errstr(status)));
 764                 return status;
 765         }
 766
 767         dns_udp_socket->send_queue = tevent_queue_create(dns_udp_socket,
 768                                                          "dns_udp_send_queue");
 769         NT_STATUS_HAVE_NO_MEMORY(dns_udp_socket->send_queue);
 770
 771         udpsubreq = tdgram_recvfrom_send(dns_udp_socket,
 772                                          dns->task->event_ctx,
 773                                          dns_udp_socket->dgram);
 774         NT_STATUS_HAVE_NO_MEMORY(udpsubreq);
 775         tevent_req_set_callback(udpsubreq, dns_udp_call_loop, dns_udp_socket);
 776
 777         return NT_STATUS_OK;
 778 }
 779
 780 /*
 781   setup our listening sockets on the configured network interfaces
 782 */
 783 static NTSTATUS dns_startup_interfaces(struct dns_server *dns, struct loadparm_context *lp_ctx,
 784                                        struct interface *ifaces)
 785 {
 786         const struct model_ops *model_ops;
 787         int num_interfaces;
 788         TALLOC_CTX *tmp_ctx = talloc_new(dns);
 789         NTSTATUS status;
 790         int i;
 791
 792         /* within the dns task we want to be a single process, so
 793            ask for the single process model ops and pass these to the
 794            stream_setup_socket() call. */
 795         model_ops = process_model_startup(dns->task->event_ctx, "single");
 796         if (!model_ops) {
 797                 DEBUG(0,("Can't find 'single' process model_ops\n"));
 798                 return NT_STATUS_INTERNAL_ERROR;
 799         }
 800
 801         num_interfaces = iface_count(ifaces);
 802
 803         for (i=0; i<num_interfaces; i++) {
 804                 const char *address = talloc_strdup(tmp_ctx, iface_n_ip(ifaces, i));
 805
 806                 status = dns_add_socket(dns, model_ops, "dns", address, DNS_SERVICE_PORT);
 807                 NT_STATUS_NOT_OK_RETURN(status);
 808         }
 809
 810         talloc_free(tmp_ctx);
 811
 812         return NT_STATUS_OK;
 813 }
 814
 815 static int dns_server_sort_zones(struct ldb_message **m1, struct ldb_message **m2)
 816 {
 817         const char *n1, *n2;
 818         size_t l1, l2;
 819
 820         n1 = ldb_msg_find_attr_as_string(*m1, "name", NULL);
 821         n2 = ldb_msg_find_attr_as_string(*m2, "name", NULL);
 822
 823         l1 = strlen(n1);
 824         l2 = strlen(n2);
 825
 826         /* If the string lengths are not equal just sort by length */
 827         if (l1 != l2) {
 828                 /* If m1 is the larger zone name, return it first */
 829                 return l2 - l1;
 830         }
 831
 832         /*TODO: We need to compare DNs here, we want the DomainDNSZones first */
 833         return 0;
 834 }
 835
 836 static void dns_task_init(struct task_server *task)
 837 {
 838         struct dns_server *dns;
 839         NTSTATUS status;
 840         struct interface *ifaces;
 841         int ret;
 842         struct ldb_result *res;
 843         struct ldb_dn *rootdn;
 844         static const char * const attrs[] = { "name", NULL};
 845         int i;
 846
 847
 848         switch (lpcfg_server_role(task->lp_ctx)) {
 849         case ROLE_STANDALONE:
 850                 task_server_terminate(task, "dns: no DNS required in standalone configuration", false);
 851                 return;
 852         case ROLE_DOMAIN_MEMBER:
 853                 task_server_terminate(task, "dns: no DNS required in member server configuration", false);
 854                 return;
 855         case ROLE_DOMAIN_CONTROLLER:
 856                 /* Yes, we want a DNS */
 857                 break;
 858         }
 859
 860         load_interfaces(task, lpcfg_interfaces(task->lp_ctx), &ifaces);
 861
 862         if (iface_count(ifaces) == 0) {
 863                 task_server_terminate(task, "dns: no network interfaces configured", false);
 864                 return;
 865         }
 866
 867         task_server_set_title(task, "task[dns]");
 868
 869         dns = talloc_zero(task, struct dns_server);
 870         if (dns == NULL) {
 871                 task_server_terminate(task, "dns: out of memory", true);
 872                 return;
 873         }
 874
 875         dns->task = task;
 876
 877         dns->samdb = samdb_connect(dns, dns->task->event_ctx, dns->task->lp_ctx,
 878                               system_session(dns->task->lp_ctx), 0);
 879         if (!dns->samdb) {
 880                 task_server_terminate(task, "dns: samdb_connect failed", true);
 881                 return;
 882         }
 883
 884         rootdn = ldb_dn_new(dns, dns->samdb, "");
 885         if (rootdn == NULL) {
 886                 task_server_terminate(task, "dns: out of memory", true);
 887                 return;
 888         }
 889
 890         // TODO: this search does not work against windows
 891         ret = dsdb_search(dns->samdb, dns, &res, rootdn, LDB_SCOPE_SUBTREE,
 892                           attrs, DSDB_SEARCH_SEARCH_ALL_PARTITIONS, "(objectClass=dnsZone)");
 893         if (ret != LDB_SUCCESS) {
 894                 task_server_terminate(task,
 895                                       "dns: failed to look up root DNS zones",
 896                                       true);
 897                 return;
 898         }
 899
 900         TYPESAFE_QSORT(res->msgs, res->count, dns_server_sort_zones);
 901
 902         for (i=0; i < res->count; i++) {
 903                 struct dns_server_zone *z;
 904
 905                 z = talloc_zero(dns, struct dns_server_zone);
 906                 if (z == NULL) {
 907                 }
 908
 909                 z->name = ldb_msg_find_attr_as_string(res->msgs[i], "name", NULL);
 910                 z->dn = talloc_move(z, &res->msgs[i]->dn);
 911
 912                 DLIST_ADD_END(dns->zones, z, NULL);
 913         }
 914
 915         status = dns_startup_interfaces(dns, task->lp_ctx, ifaces);
 916         if (!NT_STATUS_IS_OK(status)) {
 917                 task_server_terminate(task, "dns failed to setup interfaces", true);
 918                 return;
 919         }
 920 }
 921
 922 NTSTATUS server_service_dns_init(void)
 923 {
 924         return register_server_service("dns", dns_task_init);
 925 }