source4/dns_server/dns_query.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    DNS server handler for queries
   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 "libcli/util/werror.h"
  25 #include "librpc/ndr/libndr.h"
  26 #include "librpc/gen_ndr/ndr_dns.h"
  27 #include "librpc/gen_ndr/ndr_dnsp.h"
  28 #include <ldb.h>
  29 #include "param/param.h"
  30 #include "dsdb/samdb/samdb.h"
  31 #include "dsdb/common/util.h"
  32 #include "dns_server/dns_server.h"
  33 #include "libcli/dns/libdns.h"
  34 #include "lib/util/util_net.h"
  35 #include "lib/util/tevent_werror.h"
  36 #include "auth/auth.h"
  37 #include "auth/credentials/credentials.h"
  38 #include "auth/gensec/gensec.h"
  39 #include "lib/util/dlinklist.h"
  40
  41 static WERROR create_response_rr(const struct dns_name_question *question,
  42                                  const struct dnsp_DnssrvRpcRecord *rec,
  43                                  struct dns_res_rec **answers, uint16_t *ancount)
  44 {
  45         struct dns_res_rec *ans = *answers;
  46         uint16_t ai = *ancount;
  47         char *tmp;
  48         uint32_t i;
  49
  50         ZERO_STRUCT(ans[ai]);
  51
  52         switch (rec->wType) {
  53         case DNS_QTYPE_CNAME:
  54                 ans[ai].rdata.cname_record = talloc_strdup(ans, rec->data.cname);
  55                 W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.cname_record);
  56                 break;
  57         case DNS_QTYPE_A:
  58                 ans[ai].rdata.ipv4_record = talloc_strdup(ans, rec->data.ipv4);
  59                 W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.ipv4_record);
  60                 break;
  61         case DNS_QTYPE_AAAA:
  62                 ans[ai].rdata.ipv6_record = talloc_strdup(ans, rec->data.ipv6);
  63                 W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.ipv6_record);
  64                 break;
  65         case DNS_TYPE_NS:
  66                 ans[ai].rdata.ns_record = talloc_strdup(ans, rec->data.ns);
  67                 W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.ns_record);
  68                 break;
  69         case DNS_QTYPE_SRV:
  70                 ans[ai].rdata.srv_record.priority = rec->data.srv.wPriority;
  71                 ans[ai].rdata.srv_record.weight   = rec->data.srv.wWeight;
  72                 ans[ai].rdata.srv_record.port     = rec->data.srv.wPort;
  73                 ans[ai].rdata.srv_record.target   = talloc_strdup(
  74                         ans, rec->data.srv.nameTarget);
  75                 W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.srv_record.target);
  76                 break;
  77         case DNS_QTYPE_SOA:
  78                 ans[ai].rdata.soa_record.mname   = talloc_strdup(
  79                         ans, rec->data.soa.mname);
  80                 W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.soa_record.mname);
  81                 ans[ai].rdata.soa_record.rname   = talloc_strdup(
  82                         ans, rec->data.soa.rname);
  83                 W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.soa_record.rname);
  84                 ans[ai].rdata.soa_record.serial  = rec->data.soa.serial;
  85                 ans[ai].rdata.soa_record.refresh = rec->data.soa.refresh;
  86                 ans[ai].rdata.soa_record.retry   = rec->data.soa.retry;
  87                 ans[ai].rdata.soa_record.expire  = rec->data.soa.expire;
  88                 ans[ai].rdata.soa_record.minimum = rec->data.soa.minimum;
  89                 break;
  90         case DNS_QTYPE_PTR:
  91                 ans[ai].rdata.ptr_record = talloc_strdup(ans, rec->data.ptr);
  92                 break;
  93         case DNS_QTYPE_TXT:
  94                 tmp = talloc_asprintf(ans, "\"%s\"", rec->data.txt.str[0]);
  95                 W_ERROR_HAVE_NO_MEMORY(tmp);
  96                 for (i=1; i<rec->data.txt.count; i++) {
  97                         tmp = talloc_asprintf_append_buffer(
  98                                 tmp, " \"%s\"", rec->data.txt.str[i]);
  99                         W_ERROR_HAVE_NO_MEMORY(tmp);
 100                 }
 101                 ans[ai].rdata.txt_record.txt = tmp;
 102                 break;
 103         default:
 104                 DEBUG(0, ("Got unhandled type %u query.\n", rec->wType));
 105                 return DNS_ERR(NOT_IMPLEMENTED);
 106         }
 107
 108         ans[ai].name = talloc_strdup(ans, question->name);
 109         W_ERROR_HAVE_NO_MEMORY(ans[ai].name);
 110         ans[ai].rr_type = rec->wType;
 111         ans[ai].rr_class = DNS_QCLASS_IN;
 112         ans[ai].ttl = rec->dwTtlSeconds;
 113         ans[ai].length = UINT16_MAX;
 114         ai++;
 115
 116         *answers = ans;
 117         *ancount = ai;
 118
 119         return WERR_OK;
 120 }
 121
 122 struct ask_forwarder_state {
 123         struct tevent_context *ev;
 124         uint16_t id;
 125         struct dns_name_packet in_packet;
 126 };
 127
 128 static void ask_forwarder_done(struct tevent_req *subreq);
 129
 130 static struct tevent_req *ask_forwarder_send(
 131         TALLOC_CTX *mem_ctx, struct tevent_context *ev,
 132         const char *forwarder, struct dns_name_question *question)
 133 {
 134         struct tevent_req *req, *subreq;
 135         struct ask_forwarder_state *state;
 136         struct dns_name_packet out_packet = { 0, };
 137         DATA_BLOB out_blob;
 138         enum ndr_err_code ndr_err;
 139
 140         req = tevent_req_create(mem_ctx, &state, struct ask_forwarder_state);
 141         if (req == NULL) {
 142                 return NULL;
 143         }
 144         state->ev = ev;
 145         generate_random_buffer((uint8_t *)&state->id, sizeof(state->id));
 146
 147         if (!is_ipaddress(forwarder)) {
 148                 DEBUG(0, ("Invalid 'dns forwarder' setting '%s', needs to be "
 149                           "an IP address\n", forwarder));
 150                 tevent_req_werror(req, DNS_ERR(NAME_ERROR));
 151                 return tevent_req_post(req, ev);
 152         }
 153
 154         out_packet.id = state->id;
 155         out_packet.operation |= DNS_OPCODE_QUERY | DNS_FLAG_RECURSION_DESIRED;
 156         out_packet.qdcount = 1;
 157         out_packet.questions = question;
 158
 159         ndr_err = ndr_push_struct_blob(
 160                 &out_blob, state, &out_packet,
 161                 (ndr_push_flags_fn_t)ndr_push_dns_name_packet);
 162         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 163                 tevent_req_werror(req, DNS_ERR(SERVER_FAILURE));
 164                 return tevent_req_post(req, ev);
 165         }
 166         subreq = dns_udp_request_send(state, ev, forwarder, out_blob.data,
 167                                       out_blob.length);
 168         if (tevent_req_nomem(subreq, req)) {
 169                 return tevent_req_post(req, ev);
 170         }
 171         tevent_req_set_callback(subreq, ask_forwarder_done, req);
 172         return req;
 173 }
 174
 175 static void ask_forwarder_done(struct tevent_req *subreq)
 176 {
 177         struct tevent_req *req = tevent_req_callback_data(
 178                 subreq, struct tevent_req);
 179         struct ask_forwarder_state *state = tevent_req_data(
 180                 req, struct ask_forwarder_state);
 181         DATA_BLOB in_blob;
 182         enum ndr_err_code ndr_err;
 183         WERROR ret;
 184
 185         ret = dns_udp_request_recv(subreq, state,
 186                                    &in_blob.data, &in_blob.length);
 187         TALLOC_FREE(subreq);
 188         if (tevent_req_werror(req, ret)) {
 189                 return;
 190         }
 191
 192         ndr_err = ndr_pull_struct_blob(
 193                 &in_blob, state, &state->in_packet,
 194                 (ndr_pull_flags_fn_t)ndr_pull_dns_name_packet);
 195         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 196                 tevent_req_werror(req, DNS_ERR(SERVER_FAILURE));
 197                 return;
 198         }
 199         if (state->in_packet.id != state->id) {
 200                 tevent_req_werror(req, DNS_ERR(NAME_ERROR));
 201                 return;
 202         }
 203         tevent_req_done(req);
 204 }
 205
 206 static WERROR ask_forwarder_recv(
 207         struct tevent_req *req, TALLOC_CTX *mem_ctx,
 208         struct dns_res_rec **answers, uint16_t *ancount,
 209         struct dns_res_rec **nsrecs, uint16_t *nscount,
 210         struct dns_res_rec **additional, uint16_t *arcount)
 211 {
 212         struct ask_forwarder_state *state = tevent_req_data(
 213                 req, struct ask_forwarder_state);
 214         struct dns_name_packet *in_packet = &state->in_packet;
 215         WERROR err;
 216
 217         if (tevent_req_is_werror(req, &err)) {
 218                 return err;
 219         }
 220
 221         *ancount = in_packet->ancount;
 222         *answers = talloc_move(mem_ctx, &in_packet->answers);
 223
 224         *nscount = in_packet->nscount;
 225         *nsrecs = talloc_move(mem_ctx, &in_packet->nsrecs);
 226
 227         *arcount = in_packet->arcount;
 228         *additional = talloc_move(mem_ctx, &in_packet->additional);
 229
 230         return WERR_OK;
 231 }
 232
 233 static WERROR handle_question(struct dns_server *dns,
 234                               TALLOC_CTX *mem_ctx,
 235                               const struct dns_name_question *question,
 236                               struct dns_res_rec **answers, uint16_t *ancount)
 237 {
 238         struct dns_res_rec *ans = *answers;
 239         WERROR werror;
 240         unsigned int ri;
 241         struct dnsp_DnssrvRpcRecord *recs;
 242         uint16_t rec_count, ai = *ancount;
 243         struct ldb_dn *dn = NULL;
 244
 245         werror = dns_name2dn(dns, mem_ctx, question->name, &dn);
 246         W_ERROR_NOT_OK_RETURN(werror);
 247
 248         werror = dns_lookup_records(dns, mem_ctx, dn, &recs, &rec_count);
 249         W_ERROR_NOT_OK_RETURN(werror);
 250
 251         ans = talloc_realloc(mem_ctx, ans, struct dns_res_rec, rec_count + ai);
 252         if (ans == NULL) {
 253                 return WERR_NOMEM;
 254         }
 255
 256         for (ri = 0; ri < rec_count; ri++) {
 257                 if ((recs[ri].wType == DNS_TYPE_CNAME) &&
 258                     ((question->question_type == DNS_QTYPE_A) ||
 259                      (question->question_type == DNS_QTYPE_AAAA))) {
 260                         struct dns_name_question *new_q =
 261                                 talloc(mem_ctx, struct dns_name_question);
 262
 263                         if (new_q == NULL) {
 264                                 return WERR_NOMEM;
 265                         }
 266
 267                         /* We reply with one more record, so grow the array */
 268                         ans = talloc_realloc(mem_ctx, ans, struct dns_res_rec,
 269                                              rec_count + 1);
 270                         if (ans == NULL) {
 271                                 TALLOC_FREE(new_q);
 272                                 return WERR_NOMEM;
 273                         }
 274
 275                         /* First put in the CNAME record */
 276                         werror = create_response_rr(question, &recs[ri], &ans, &ai);
 277                         if (!W_ERROR_IS_OK(werror)) {
 278                                 return werror;
 279                         }
 280
 281                         /* And then look up the name it points at.. */
 282
 283                         /* First build up the new question */
 284                         new_q->question_type = question->question_type;
 285                         new_q->question_class = question->question_class;
 286                         if (new_q->question_type == DNS_QTYPE_A) {
 287                                 new_q->name = talloc_strdup(new_q, recs[ri].data.ipv4);
 288                         } else if (new_q->question_type == DNS_QTYPE_AAAA) {
 289                                 new_q->name = talloc_strdup(new_q, recs[ri].data.ipv6);
 290                         }
 291                         if (new_q->name == NULL) {
 292                                 TALLOC_FREE(new_q);
 293                                 return WERR_NOMEM;
 294                         }
 295                         /* and then call the lookup again */
 296                         werror = handle_question(dns, mem_ctx, new_q, &ans, &ai);
 297                         if (!W_ERROR_IS_OK(werror)) {
 298                                 return werror;
 299                         }
 300
 301
 302                         continue;
 303                 }
 304                 if ((question->question_type != DNS_QTYPE_ALL) &&
 305                     (recs[ri].wType != question->question_type)) {
 306                         continue;
 307                 }
 308                 werror = create_response_rr(question, &recs[ri], &ans, &ai);
 309                 if (!W_ERROR_IS_OK(werror)) {
 310                         return werror;
 311                 }
 312         }
 313
 314         if (ai == 0) {
 315                 return DNS_ERR(NAME_ERROR);
 316         }
 317
 318         *ancount = ai;
 319         *answers = ans;
 320
 321         return WERR_OK;
 322 }
 323
 324 static NTSTATUS create_new_tkey(TALLOC_CTX *mem_ctx,
 325                                 struct dns_server *dns,
 326                                 struct dns_server_tkey **tkey,
 327                                 const char* name)
 328 {
 329         NTSTATUS status;
 330         struct dns_server_tkey *k = talloc_zero(mem_ctx, struct dns_server_tkey);
 331
 332         if (k == NULL) {
 333                 return NT_STATUS_NO_MEMORY;
 334         }
 335
 336         k->name = talloc_strdup(mem_ctx, name);
 337
 338         if (k->name  == NULL) {
 339                 return NT_STATUS_NO_MEMORY;
 340         }
 341
 342         status = samba_server_gensec_start(k,
 343                                            dns->task->event_ctx,
 344                                            dns->task->msg_ctx,
 345                                            dns->task->lp_ctx,
 346                                            dns->server_credentials,
 347                                            "dns",
 348                                            &k->gensec);
 349         if (!NT_STATUS_IS_OK(status)) {
 350                 DEBUG(1, ("Failed to start GENSEC server code: %s\n", nt_errstr(status)));
 351                 *tkey = NULL;
 352                 return status;
 353         }
 354
 355         gensec_want_feature(k->gensec, GENSEC_FEATURE_SIGN);
 356
 357         status = gensec_start_mech_by_oid(k->gensec, GENSEC_OID_SPNEGO);
 358
 359         if (!NT_STATUS_IS_OK(status)) {
 360                 DEBUG(1, ("Failed to start GENSEC server code: %s\n",
 361                           nt_errstr(status)));
 362                 *tkey = NULL;
 363                 return status;
 364         }
 365
 366         *tkey = k;
 367         return NT_STATUS_OK;
 368 }
 369
 370 static NTSTATUS accept_gss_ticket(TALLOC_CTX *mem_ctx,
 371                                   struct dns_server *dns,
 372                                   struct dns_server_tkey *tkey,
 373                                   const DATA_BLOB *key,
 374                                   DATA_BLOB *reply,
 375                                   uint16_t *dns_auth_error)
 376 {
 377         NTSTATUS status;
 378
 379         status = gensec_update(tkey->gensec, mem_ctx, dns->task->event_ctx,
 380                                *key, reply);
 381
 382         if (NT_STATUS_EQUAL(NT_STATUS_MORE_PROCESSING_REQUIRED, status)) {
 383                 *dns_auth_error = DNS_RCODE_OK;
 384                 return status;
 385         }
 386
 387         if (NT_STATUS_IS_OK(status)) {
 388
 389                 status = gensec_session_info(tkey->gensec, tkey, &tkey->session_info);
 390                 if (!NT_STATUS_IS_OK(status)) {
 391                         *dns_auth_error = DNS_RCODE_BADKEY;
 392                         return status;
 393                 }
 394                 *dns_auth_error = DNS_RCODE_OK;
 395         }
 396
 397         return status;
 398 }
 399
 400 static struct dns_server_tkey *find_tkey(struct dns_server *dns,
 401                                          const char *name)
 402 {
 403         struct dns_server_tkey *tkey = NULL;
 404
 405         for (tkey = dns->tkeys; tkey != NULL; tkey = tkey->next) {
 406                 if (dns_name_equal(name, tkey->name)) {
 407                         break;
 408                 }
 409         }
 410
 411         return tkey;
 412 }
 413
 414 static WERROR handle_tkey(struct dns_server *dns,
 415                           TALLOC_CTX *mem_ctx,
 416                           const struct dns_name_packet *in,
 417                           struct dns_res_rec **answers,
 418                           uint16_t *ancount)
 419 {
 420         struct dns_res_rec *in_tkey = NULL;
 421         struct dns_res_rec *ret_tkey;
 422         uint16_t i;
 423
 424         for (i = 0; i < in->arcount; i++) {
 425                 if (in->additional[i].rr_type == DNS_QTYPE_TKEY) {
 426                         in_tkey = &in->additional[i];
 427                         break;
 428                 }
 429         }
 430
 431         /* If this is a TKEY query, it should have a TKEY RR.
 432          * Behaviour is not really specified in RFC 2930 or RFC 3645, but
 433          * FORMAT_ERROR seems to be what BIND uses .*/
 434         if (in_tkey == NULL) {
 435                 return DNS_ERR(FORMAT_ERROR);
 436         }
 437
 438         ret_tkey = talloc_zero(mem_ctx, struct dns_res_rec);
 439         if (ret_tkey == NULL) {
 440                 return WERR_NOMEM;
 441         }
 442
 443         ret_tkey->name = talloc_strdup(ret_tkey, in_tkey->name);
 444         if (ret_tkey->name == NULL) {
 445                 return WERR_NOMEM;
 446         }
 447
 448         ret_tkey->rr_type = DNS_QTYPE_TKEY;
 449         ret_tkey->rr_class = DNS_QCLASS_ANY;
 450         ret_tkey->length = UINT16_MAX;
 451
 452         ret_tkey->rdata.tkey_record.algorithm = talloc_strdup(ret_tkey, ret_tkey->name);
 453         if (ret_tkey->rdata.tkey_record.algorithm  == NULL) {
 454                 return WERR_NOMEM;
 455         }
 456
 457         ret_tkey->rdata.tkey_record.inception = in_tkey->rdata.tkey_record.inception;
 458         ret_tkey->rdata.tkey_record.expiration = in_tkey->rdata.tkey_record.expiration;
 459         ret_tkey->rdata.tkey_record.mode = in_tkey->rdata.tkey_record.mode;
 460
 461         switch (in_tkey->rdata.tkey_record.mode) {
 462         case DNS_TKEY_MODE_DH:
 463                 /* FIXME: According to RFC 2930, we MUST support this, but we don't.
 464                  * Still, claim it's a bad key instead of a bad mode */
 465                 ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADKEY;
 466                 break;
 467         case DNS_TKEY_MODE_GSSAPI: {
 468                 NTSTATUS status;
 469                 struct dns_server_tkey *tkey;
 470                 DATA_BLOB key;
 471                 DATA_BLOB reply;
 472
 473                 tkey = find_tkey(dns, in->questions[0].name);
 474                 if (tkey != NULL && tkey->complete) {
 475                         /* TODO: check if the key is still valid */
 476                         DEBUG(1, ("Rejecting tkey negotiation for already established key\n"));
 477                         ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADNAME;
 478                         break;
 479                 }
 480
 481                 if (tkey == NULL) {
 482                         status  = create_new_tkey(dns, dns, &tkey,
 483                                                   in->questions[0].name);
 484                         if (!NT_STATUS_IS_OK(status)) {
 485                                 ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADKEY;
 486                                 return ntstatus_to_werror(status);
 487                         }
 488
 489                         DLIST_ADD_END(dns->tkeys, tkey, NULL);
 490                 }
 491
 492                 key.data = in_tkey->rdata.tkey_record.key_data;
 493                 key.length = in_tkey->rdata.tkey_record.key_size;
 494
 495                 status = accept_gss_ticket(ret_tkey, dns, tkey, &key, &reply,
 496                                            &ret_tkey->rdata.tkey_record.error);
 497                 if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 498                         DEBUG(1, ("More processing required\n"));
 499                         ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADKEY;
 500                 } else if (NT_STATUS_IS_OK(status)) {
 501                         DEBUG(1, ("Tkey handshake completed\n"));
 502                 } else {
 503                         DEBUG(0, ("GSS key negotiation returned %s\n", nt_errstr(status)));
 504                         ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADKEY;
 505                 }
 506
 507                 break;
 508                 }
 509         case DNS_TKEY_MODE_DELETE:
 510                 /* TODO: implement me */
 511                 DEBUG(1, ("Should delete tkey here\n"));
 512                 ret_tkey->rdata.tkey_record.error = DNS_RCODE_OK;
 513                 break;
 514         case DNS_TKEY_MODE_NULL:
 515         case DNS_TKEY_MODE_SERVER:
 516         case DNS_TKEY_MODE_CLIENT:
 517         case DNS_TKEY_MODE_LAST:
 518                 /* We don't have to implement these, return a mode error */
 519                 ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADMODE;
 520                 break;
 521         default:
 522                 DEBUG(1, ("Unsupported TKEY mode %d\n",
 523                       in_tkey->rdata.tkey_record.mode));
 524         }
 525
 526         *answers = ret_tkey;
 527         *ancount = 1;
 528
 529         return WERR_OK;
 530 }
 531
 532 struct dns_server_process_query_state {
 533         struct dns_res_rec *answers;
 534         uint16_t ancount;
 535         struct dns_res_rec *nsrecs;
 536         uint16_t nscount;
 537         struct dns_res_rec *additional;
 538         uint16_t arcount;
 539 };
 540
 541 static void dns_server_process_query_got_response(struct tevent_req *subreq);
 542
 543 struct tevent_req *dns_server_process_query_send(
 544         TALLOC_CTX *mem_ctx, struct tevent_context *ev,
 545         struct dns_server *dns, struct dns_request_state *req_state,
 546         const struct dns_name_packet *in)
 547 {
 548         struct tevent_req *req, *subreq;
 549         struct dns_server_process_query_state *state;
 550
 551         req = tevent_req_create(mem_ctx, &state,
 552                                 struct dns_server_process_query_state);
 553         if (req == NULL) {
 554                 return NULL;
 555         }
 556         if (in->qdcount != 1) {
 557                 tevent_req_werror(req, DNS_ERR(FORMAT_ERROR));
 558                 return tevent_req_post(req, ev);
 559         }
 560
 561         /* Windows returns NOT_IMPLEMENTED on this as well */
 562         if (in->questions[0].question_class == DNS_QCLASS_NONE) {
 563                 tevent_req_werror(req, DNS_ERR(NOT_IMPLEMENTED));
 564                 return tevent_req_post(req, ev);
 565         }
 566
 567         if (in->questions[0].question_type == DNS_QTYPE_TKEY) {
 568                 WERROR err;
 569
 570                 err = handle_tkey(dns, state, in, &state->answers,
 571                                   &state->ancount);
 572                 if (tevent_req_werror(req, err)) {
 573                         return tevent_req_post(req, ev);
 574                 }
 575                 tevent_req_done(req);
 576                 return tevent_req_post(req, ev);
 577         }
 578
 579         if (dns_authorative_for_zone(dns, in->questions[0].name)) {
 580                 WERROR err;
 581
 582                 req_state->flags |= DNS_FLAG_AUTHORITATIVE;
 583                 err = handle_question(dns, state, &in->questions[0],
 584                                       &state->answers, &state->ancount);
 585                 if (tevent_req_werror(req, err)) {
 586                         return tevent_req_post(req, ev);
 587                 }
 588                 tevent_req_done(req);
 589                 return tevent_req_post(req, ev);
 590         }
 591
 592         if ((req_state->flags & DNS_FLAG_RECURSION_DESIRED) &&
 593             (req_state->flags & DNS_FLAG_RECURSION_AVAIL)) {
 594                 DEBUG(2, ("Not authoritative for '%s', forwarding\n",
 595                           in->questions[0].name));
 596
 597                 subreq = ask_forwarder_send(
 598                         state, ev, lpcfg_dns_forwarder(dns->task->lp_ctx),
 599                         &in->questions[0]);
 600                 if (tevent_req_nomem(subreq, req)) {
 601                         return tevent_req_post(req, ev);
 602                 }
 603                 tevent_req_set_callback(
 604                         subreq, dns_server_process_query_got_response, req);
 605                 return req;
 606         }
 607
 608         tevent_req_werror(req, DNS_ERR(NAME_ERROR));
 609         return tevent_req_post(req, ev);
 610 }
 611
 612 static void dns_server_process_query_got_response(struct tevent_req *subreq)
 613 {
 614         struct tevent_req *req = tevent_req_callback_data(
 615                 subreq, struct tevent_req);
 616         struct dns_server_process_query_state *state = tevent_req_data(
 617                 req, struct dns_server_process_query_state);
 618         WERROR err;
 619
 620         err = ask_forwarder_recv(subreq, state,
 621                                  &state->answers, &state->ancount,
 622                                  &state->nsrecs, &state->nscount,
 623                                  &state->additional, &state->arcount);
 624         TALLOC_FREE(subreq);
 625         if (tevent_req_werror(req, err)) {
 626                 return;
 627         }
 628         tevent_req_done(req);
 629 }
 630
 631 WERROR dns_server_process_query_recv(
 632         struct tevent_req *req, TALLOC_CTX *mem_ctx,
 633         struct dns_res_rec **answers,    uint16_t *ancount,
 634         struct dns_res_rec **nsrecs,     uint16_t *nscount,
 635         struct dns_res_rec **additional, uint16_t *arcount)
 636 {
 637         struct dns_server_process_query_state *state = tevent_req_data(
 638                 req, struct dns_server_process_query_state);
 639         WERROR err;
 640
 641         if (tevent_req_is_werror(req, &err)) {
 642                 return err;
 643         }
 644         *answers = talloc_move(mem_ctx, &state->answers);
 645         *ancount = state->ancount;
 646         *nsrecs = talloc_move(mem_ctx, &state->nsrecs);
 647         *nscount = state->nscount;
 648         *additional = talloc_move(mem_ctx, &state->additional);
 649         *arcount = state->arcount;
 650         return WERR_OK;
 651 }