source3/libsmb/unexpected.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    handle unexpected packets
   4    Copyright (C) Andrew Tridgell 2000
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 */
  20
  21 #include "includes.h"
  22 #include "../lib/util/tevent_ntstatus.h"
  23 #include "lib/async_req/async_sock.h"
  24 #include "libsmb/nmblib.h"
  25 #include "lib/sys_rw.h"
  26
  27 static const char *nmbd_socket_dir(void)
  28 {
  29         return lp_parm_const_string(-1, "nmbd", "socket dir",
  30                                     get_dyn_NMBDSOCKETDIR());
  31 }
  32
  33 struct nb_packet_query {
  34         enum packet_type type;
  35         size_t mailslot_namelen;
  36         int trn_id;
  37 };
  38
  39 struct nb_packet_client;
  40
  41 struct nb_packet_server {
  42         struct tevent_context *ev;
  43         int listen_sock;
  44         int max_clients;
  45         int num_clients;
  46         struct nb_packet_client *clients;
  47 };
  48
  49 struct nb_packet_client {
  50         struct nb_packet_client *prev, *next;
  51         struct nb_packet_server *server;
  52
  53         enum packet_type type;
  54         int trn_id;
  55         char *mailslot_name;
  56
  57         int sock;
  58         struct tevent_req *read_req;
  59         struct tevent_queue *out_queue;
  60 };
  61
  62 static int nb_packet_server_destructor(struct nb_packet_server *s);
  63 static void nb_packet_server_listener(struct tevent_context *ev,
  64                                       struct tevent_fd *fde,
  65                                       uint16_t flags,
  66                                       void *private_data);
  67
  68 NTSTATUS nb_packet_server_create(TALLOC_CTX *mem_ctx,
  69                                  struct tevent_context *ev,
  70                                  int max_clients,
  71                                  struct nb_packet_server **presult)
  72 {
  73         struct nb_packet_server *result;
  74         struct tevent_fd *fde;
  75         NTSTATUS status;
  76         int rc;
  77
  78         result = talloc_zero(mem_ctx, struct nb_packet_server);
  79         if (result == NULL) {
  80                 status = NT_STATUS_NO_MEMORY;
  81                 goto fail;
  82         }
  83         result->ev = ev;
  84         result->max_clients = max_clients;
  85
  86         result->listen_sock = create_pipe_sock(
  87                 nmbd_socket_dir(), "unexpected", 0755);
  88         if (result->listen_sock == -1) {
  89                 status = map_nt_error_from_unix(errno);
  90                 goto fail;
  91         }
  92         rc = listen(result->listen_sock, 5);
  93         if (rc < 0) {
  94                 status = map_nt_error_from_unix(errno);
  95                 goto fail;
  96         }
  97         talloc_set_destructor(result, nb_packet_server_destructor);
  98
  99         fde = tevent_add_fd(ev, result, result->listen_sock, TEVENT_FD_READ,
 100                             nb_packet_server_listener, result);
 101         if (fde == NULL) {
 102                 status = NT_STATUS_NO_MEMORY;
 103                 goto fail;
 104         }
 105
 106         *presult = result;
 107         return NT_STATUS_OK;
 108 fail:
 109         TALLOC_FREE(result);
 110         return status;
 111 }
 112
 113 static int nb_packet_server_destructor(struct nb_packet_server *s)
 114 {
 115         if (s->listen_sock != -1) {
 116                 close(s->listen_sock);
 117                 s->listen_sock = -1;
 118         }
 119         return 0;
 120 }
 121
 122 static int nb_packet_client_destructor(struct nb_packet_client *c);
 123 static ssize_t nb_packet_client_more(uint8_t *buf, size_t buflen,
 124                                      void *private_data);
 125 static void nb_packet_got_query(struct tevent_req *req);
 126 static void nb_packet_client_read_done(struct tevent_req *req);
 127
 128 static void nb_packet_server_listener(struct tevent_context *ev,
 129                                       struct tevent_fd *fde,
 130                                       uint16_t flags,
 131                                       void *private_data)
 132 {
 133         struct nb_packet_server *server = talloc_get_type_abort(
 134                 private_data, struct nb_packet_server);
 135         struct nb_packet_client *client;
 136         struct tevent_req *req;
 137         struct sockaddr_un sunaddr;
 138         socklen_t len;
 139         int sock;
 140
 141         len = sizeof(sunaddr);
 142
 143         sock = accept(server->listen_sock, (struct sockaddr *)(void *)&sunaddr,
 144                       &len);
 145         if (sock == -1) {
 146                 return;
 147         }
 148         DEBUG(6,("accepted socket %d\n", sock));
 149
 150         client = talloc_zero(server, struct nb_packet_client);
 151         if (client == NULL) {
 152                 DEBUG(10, ("talloc failed\n"));
 153                 close(sock);
 154                 return;
 155         }
 156         client->sock = sock;
 157         client->server = server;
 158         talloc_set_destructor(client, nb_packet_client_destructor);
 159
 160         client->out_queue = tevent_queue_create(
 161                 client, "unexpected packet output");
 162         if (client->out_queue == NULL) {
 163                 DEBUG(10, ("tevent_queue_create failed\n"));
 164                 TALLOC_FREE(client);
 165                 return;
 166         }
 167
 168         req = read_packet_send(client, ev, client->sock,
 169                                sizeof(struct nb_packet_query),
 170                                nb_packet_client_more, NULL);
 171         if (req == NULL) {
 172                 DEBUG(10, ("read_packet_send failed\n"));
 173                 TALLOC_FREE(client);
 174                 return;
 175         }
 176         tevent_req_set_callback(req, nb_packet_got_query, client);
 177
 178         DLIST_ADD(server->clients, client);
 179         server->num_clients += 1;
 180
 181         if (server->num_clients > server->max_clients) {
 182                 DEBUG(10, ("Too many clients, dropping oldest\n"));
 183
 184                 /*
 185                  * no TALLOC_FREE here, don't mess with the list structs
 186                  */
 187                 talloc_free(server->clients->prev);
 188         }
 189 }
 190
 191 static ssize_t nb_packet_client_more(uint8_t *buf, size_t buflen,
 192                                      void *private_data)
 193 {
 194         struct nb_packet_query q;
 195         if (buflen > sizeof(struct nb_packet_query)) {
 196                 return 0;
 197         }
 198         /* Take care of alignment */
 199         memcpy(&q, buf, sizeof(q));
 200         if (q.mailslot_namelen > 1024) {
 201                 DEBUG(10, ("Got invalid mailslot namelen %d\n",
 202                            (int)q.mailslot_namelen));
 203                 return -1;
 204         }
 205         return q.mailslot_namelen;
 206 }
 207
 208 static int nb_packet_client_destructor(struct nb_packet_client *c)
 209 {
 210         if (c->sock != -1) {
 211                 close(c->sock);
 212                 c->sock = -1;
 213         }
 214         DLIST_REMOVE(c->server->clients, c);
 215         c->server->num_clients -= 1;
 216         return 0;
 217 }
 218
 219 static void nb_packet_got_query(struct tevent_req *req)
 220 {
 221         struct nb_packet_client *client = tevent_req_callback_data(
 222                 req, struct nb_packet_client);
 223         struct nb_packet_query q;
 224         uint8_t *buf;
 225         ssize_t nread, nwritten;
 226         int err;
 227         char c;
 228
 229         nread = read_packet_recv(req, talloc_tos(), &buf, &err);
 230         TALLOC_FREE(req);
 231         if (nread < (ssize_t)sizeof(struct nb_packet_query)) {
 232                 DEBUG(10, ("read_packet_recv returned %d (%s)\n",
 233                            (int)nread,
 234                            (nread == -1) ? strerror(err) : "wrong length"));
 235                 TALLOC_FREE(client);
 236                 return;
 237         }
 238
 239         /* Take care of alignment */
 240         memcpy(&q, buf, sizeof(q));
 241
 242         if (nread != sizeof(struct nb_packet_query) + q.mailslot_namelen) {
 243                 DEBUG(10, ("nb_packet_got_query: Invalid mailslot namelength\n"));
 244                 TALLOC_FREE(client);
 245                 return;
 246         }
 247
 248         client->trn_id = q.trn_id;
 249         client->type = q.type;
 250         if (q.mailslot_namelen > 0) {
 251                 client->mailslot_name = talloc_strndup(
 252                         client, (char *)buf + sizeof(q),
 253                         q.mailslot_namelen);
 254                 if (client->mailslot_name == NULL) {
 255                         TALLOC_FREE(client);
 256                         return;
 257                 }
 258         }
 259
 260         /*
 261          * Yes, this is a blocking write of 1 byte into a unix
 262          * domain socket that has never been written to. Highly
 263          * unlikely that this actually blocks.
 264          */
 265         c = 0;
 266         nwritten = sys_write(client->sock, &c, sizeof(c));
 267         if (nwritten != sizeof(c)) {
 268                 DEBUG(10, ("Could not write success indicator to client: %s\n",
 269                            strerror(errno)));
 270                 TALLOC_FREE(client);
 271                 return;
 272         }
 273
 274         client->read_req = read_packet_send(client, client->server->ev,
 275                                             client->sock, 1, NULL, NULL);
 276         if (client->read_req == NULL) {
 277                 DEBUG(10, ("Could not activate reader for client exit "
 278                            "detection\n"));
 279                 TALLOC_FREE(client);
 280                 return;
 281         }
 282         tevent_req_set_callback(client->read_req, nb_packet_client_read_done,
 283                                 client);
 284 }
 285
 286 static void nb_packet_client_read_done(struct tevent_req *req)
 287 {
 288         struct nb_packet_client *client = tevent_req_callback_data(
 289                 req, struct nb_packet_client);
 290         ssize_t nread;
 291         uint8_t *buf;
 292         int err;
 293
 294         nread = read_packet_recv(req, talloc_tos(), &buf, &err);
 295         TALLOC_FREE(req);
 296         if (nread == 1) {
 297                 DEBUG(10, ("Protocol error, received data on write-only "
 298                            "unexpected socket: 0x%2.2x\n", (*buf)));
 299         }
 300         TALLOC_FREE(client);
 301 }
 302
 303 static void nb_packet_client_send(struct nb_packet_client *client,
 304                                   struct packet_struct *p);
 305
 306 void nb_packet_dispatch(struct nb_packet_server *server,
 307                         struct packet_struct *p)
 308 {
 309         struct nb_packet_client *c;
 310         uint16_t trn_id;
 311
 312         switch (p->packet_type) {
 313         case NMB_PACKET:
 314                 trn_id = p->packet.nmb.header.name_trn_id;
 315                 break;
 316         case DGRAM_PACKET:
 317                 trn_id = p->packet.dgram.header.dgm_id;
 318                 break;
 319         default:
 320                 DEBUG(10, ("Got invalid packet type %d\n",
 321                            (int)p->packet_type));
 322                 return;
 323         }
 324         for (c = server->clients; c != NULL; c = c->next) {
 325
 326                 if (c->type != p->packet_type) {
 327                         DEBUG(10, ("client expects packet %d, got %d\n",
 328                                    c->type, p->packet_type));
 329                         continue;
 330                 }
 331
 332                 if (p->packet_type == NMB_PACKET) {
 333                         /*
 334                          * See if the client specified transaction
 335                          * ID. Filter if it did.
 336                          */
 337                         if ((c->trn_id != -1) &&
 338                             (c->trn_id != trn_id)) {
 339                                 DEBUG(10, ("client expects trn %d, got %d\n",
 340                                            c->trn_id, trn_id));
 341                                 continue;
 342                         }
 343                 } else {
 344                         /*
 345                          * See if the client specified a mailslot
 346                          * name. Filter if it did.
 347                          */
 348                         if ((c->mailslot_name != NULL) &&
 349                             !match_mailslot_name(p, c->mailslot_name)) {
 350                                 continue;
 351                         }
 352                 }
 353                 nb_packet_client_send(c, p);
 354         }
 355 }
 356
 357 struct nb_packet_client_header {
 358         size_t len;
 359         enum packet_type type;
 360         time_t timestamp;
 361         struct in_addr ip;
 362         int port;
 363 };
 364
 365 struct nb_packet_client_state {
 366         struct nb_packet_client *client;
 367         struct iovec iov[2];
 368         struct nb_packet_client_header hdr;
 369         char buf[1024];
 370 };
 371
 372 static void nb_packet_client_send_done(struct tevent_req *req);
 373
 374 static void nb_packet_client_send(struct nb_packet_client *client,
 375                                   struct packet_struct *p)
 376 {
 377         struct nb_packet_client_state *state;
 378         struct tevent_req *req;
 379
 380         if (tevent_queue_length(client->out_queue) > 10) {
 381                 /*
 382                  * Skip clients that don't listen anyway, some form of DoS
 383                  * protection
 384                  */
 385                 return;
 386         }
 387
 388         state = talloc_zero(client, struct nb_packet_client_state);
 389         if (state == NULL) {
 390                 DEBUG(10, ("talloc failed\n"));
 391                 return;
 392         }
 393
 394         state->client = client;
 395
 396         state->hdr.ip = p->ip;
 397         state->hdr.port = p->port;
 398         state->hdr.timestamp = p->timestamp;
 399         state->hdr.type = p->packet_type;
 400         state->hdr.len = build_packet(state->buf, sizeof(state->buf), p);
 401
 402         state->iov[0].iov_base = (char *)&state->hdr;
 403         state->iov[0].iov_len = sizeof(state->hdr);
 404         state->iov[1].iov_base = state->buf;
 405         state->iov[1].iov_len = state->hdr.len;
 406
 407         TALLOC_FREE(client->read_req);
 408
 409         req = writev_send(client, client->server->ev, client->out_queue,
 410                           client->sock, true, state->iov, 2);
 411         if (req == NULL) {
 412                 DEBUG(10, ("writev_send failed\n"));
 413                 return;
 414         }
 415         tevent_req_set_callback(req, nb_packet_client_send_done, state);
 416 }
 417
 418 static void nb_packet_client_send_done(struct tevent_req *req)
 419 {
 420         struct nb_packet_client_state *state = tevent_req_callback_data(
 421                 req, struct nb_packet_client_state);
 422         struct nb_packet_client *client = state->client;
 423         ssize_t nwritten;
 424         int err;
 425
 426         nwritten = writev_recv(req, &err);
 427
 428         TALLOC_FREE(req);
 429         TALLOC_FREE(state);
 430
 431         if (nwritten == -1) {
 432                 DEBUG(10, ("writev failed: %s\n", strerror(err)));
 433                 TALLOC_FREE(client);
 434         }
 435
 436         if (tevent_queue_length(client->out_queue) == 0) {
 437                 client->read_req = read_packet_send(client, client->server->ev,
 438                                                     client->sock, 1,
 439                                                     NULL, NULL);
 440                 if (client->read_req == NULL) {
 441                         DEBUG(10, ("Could not activate reader for client exit "
 442                                    "detection\n"));
 443                         TALLOC_FREE(client);
 444                         return;
 445                 }
 446                 tevent_req_set_callback(client->read_req,
 447                                         nb_packet_client_read_done,
 448                                         client);
 449         }
 450 }
 451
 452 struct nb_packet_reader {
 453         int sock;
 454 };
 455
 456 struct nb_packet_reader_state {
 457         struct tevent_context *ev;
 458         struct sockaddr_un addr;
 459         struct nb_packet_query query;
 460         const char *mailslot_name;
 461         struct iovec iov[2];
 462         char c;
 463         struct nb_packet_reader *reader;
 464 };
 465
 466 static int nb_packet_reader_destructor(struct nb_packet_reader *r);
 467 static void nb_packet_reader_connected(struct tevent_req *subreq);
 468 static void nb_packet_reader_sent_query(struct tevent_req *subreq);
 469 static void nb_packet_reader_got_ack(struct tevent_req *subreq);
 470
 471 struct tevent_req *nb_packet_reader_send(TALLOC_CTX *mem_ctx,
 472                                          struct tevent_context *ev,
 473                                          enum packet_type type,
 474                                          int trn_id,
 475                                          const char *mailslot_name)
 476 {
 477         struct tevent_req *req, *subreq;
 478         struct nb_packet_reader_state *state;
 479         char *path;
 480
 481         req = tevent_req_create(mem_ctx, &state,
 482                                 struct nb_packet_reader_state);
 483         if (req == NULL) {
 484                 return NULL;
 485         }
 486         state->ev = ev;
 487         state->query.trn_id = trn_id;
 488         state->query.type = type;
 489         state->mailslot_name = mailslot_name;
 490
 491         if (mailslot_name != NULL) {
 492                 state->query.mailslot_namelen = strlen(mailslot_name);
 493         }
 494
 495         state->reader = talloc_zero(state, struct nb_packet_reader);
 496         if (tevent_req_nomem(state->reader, req)) {
 497                 return tevent_req_post(req, ev);
 498         }
 499
 500         path = talloc_asprintf(talloc_tos(), "%s/%s", nmbd_socket_dir(),
 501                                "unexpected");
 502         if (tevent_req_nomem(path, req)) {
 503                 return tevent_req_post(req, ev);
 504         }
 505         state->addr.sun_family = AF_UNIX;
 506         strlcpy(state->addr.sun_path, path, sizeof(state->addr.sun_path));
 507         TALLOC_FREE(path);
 508
 509         state->reader->sock = socket(AF_UNIX, SOCK_STREAM, 0);
 510         if (state->reader->sock == -1) {
 511                 tevent_req_nterror(req, map_nt_error_from_unix(errno));
 512                 return tevent_req_post(req, ev);
 513         }
 514         talloc_set_destructor(state->reader, nb_packet_reader_destructor);
 515
 516         subreq = async_connect_send(state, ev, state->reader->sock,
 517                                     (struct sockaddr *)(void *)&state->addr,
 518                                     sizeof(state->addr), NULL, NULL, NULL);
 519         if (tevent_req_nomem(subreq, req)) {
 520                 return tevent_req_post(req, ev);
 521         }
 522         tevent_req_set_callback(subreq, nb_packet_reader_connected, req);
 523         return req;
 524 }
 525
 526 static int nb_packet_reader_destructor(struct nb_packet_reader *r)
 527 {
 528         if (r->sock != -1) {
 529                 close(r->sock);
 530                 r->sock = -1;
 531         }
 532         return 0;
 533 }
 534
 535 static void nb_packet_reader_connected(struct tevent_req *subreq)
 536 {
 537         struct tevent_req *req = tevent_req_callback_data(
 538                 subreq, struct tevent_req);
 539         struct nb_packet_reader_state *state = tevent_req_data(
 540                 req, struct nb_packet_reader_state);
 541         int res, err;
 542         int num_iovecs = 1;
 543
 544         res = async_connect_recv(subreq, &err);
 545         TALLOC_FREE(subreq);
 546         if (res == -1) {
 547                 DEBUG(10, ("async_connect failed: %s\n", strerror(err)));
 548                 tevent_req_nterror(req, map_nt_error_from_unix(err));
 549                 return;
 550         }
 551
 552         state->iov[0].iov_base = (char *)&state->query;
 553         state->iov[0].iov_len = sizeof(state->query);
 554
 555         if (state->mailslot_name != NULL) {
 556                 num_iovecs = 2;
 557                 state->iov[1].iov_base = discard_const_p(
 558                         char, state->mailslot_name);
 559                 state->iov[1].iov_len = state->query.mailslot_namelen;
 560         }
 561
 562         subreq = writev_send(state, state->ev, NULL, state->reader->sock,
 563                              true, state->iov, num_iovecs);
 564         if (tevent_req_nomem(subreq, req)) {
 565                 return;
 566         }
 567         tevent_req_set_callback(subreq, nb_packet_reader_sent_query, req);
 568 }
 569
 570 static void nb_packet_reader_sent_query(struct tevent_req *subreq)
 571 {
 572         struct tevent_req *req = tevent_req_callback_data(
 573                 subreq, struct tevent_req);
 574         struct nb_packet_reader_state *state = tevent_req_data(
 575                 req, struct nb_packet_reader_state);
 576         ssize_t written;
 577         int err;
 578
 579         written = writev_recv(subreq, &err);
 580         TALLOC_FREE(subreq);
 581         if (written == -1) {
 582                 tevent_req_nterror(req, map_nt_error_from_unix(err));
 583                 return;
 584         }
 585         if (written != sizeof(state->query) + state->query.mailslot_namelen) {
 586                 tevent_req_nterror(req, NT_STATUS_UNEXPECTED_IO_ERROR);
 587                 return;
 588         }
 589         subreq = read_packet_send(state, state->ev, state->reader->sock,
 590                                   sizeof(state->c), NULL, NULL);
 591         if (tevent_req_nomem(subreq, req)) {
 592                 return;
 593         }
 594         tevent_req_set_callback(subreq, nb_packet_reader_got_ack, req);
 595 }
 596
 597 static void nb_packet_reader_got_ack(struct tevent_req *subreq)
 598 {
 599         struct tevent_req *req = tevent_req_callback_data(
 600                 subreq, struct tevent_req);
 601         struct nb_packet_reader_state *state = tevent_req_data(
 602                 req, struct nb_packet_reader_state);
 603         ssize_t nread;
 604         int err;
 605         uint8_t *buf;
 606
 607         nread = read_packet_recv(subreq, state, &buf, &err);
 608         TALLOC_FREE(subreq);
 609         if (nread == -1) {
 610                 DEBUG(10, ("read_packet_recv returned %s\n",
 611                            strerror(err)));
 612                 tevent_req_nterror(req, map_nt_error_from_unix(err));
 613                 return;
 614         }
 615         if (nread != sizeof(state->c)) {
 616                 DEBUG(10, ("read = %d, expected %d\n", (int)nread,
 617                            (int)sizeof(state->c)));
 618                 tevent_req_nterror(req, NT_STATUS_UNEXPECTED_IO_ERROR);
 619                 return;
 620         }
 621         tevent_req_done(req);
 622 }
 623
 624 NTSTATUS nb_packet_reader_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 625                                struct nb_packet_reader **preader)
 626 {
 627         struct nb_packet_reader_state *state = tevent_req_data(
 628                 req, struct nb_packet_reader_state);
 629         NTSTATUS status;
 630
 631         if (tevent_req_is_nterror(req, &status)) {
 632                 return status;
 633         }
 634         *preader = talloc_move(mem_ctx, &state->reader);
 635         return NT_STATUS_OK;
 636 }
 637
 638 struct nb_packet_read_state {
 639         struct nb_packet_client_header hdr;
 640         uint8_t *buf;
 641         size_t buflen;
 642 };
 643
 644 static ssize_t nb_packet_read_more(uint8_t *buf, size_t buflen, void *p);
 645 static void nb_packet_read_done(struct tevent_req *subreq);
 646
 647 struct tevent_req *nb_packet_read_send(TALLOC_CTX *mem_ctx,
 648                                        struct tevent_context *ev,
 649                                        struct nb_packet_reader *reader)
 650 {
 651         struct tevent_req *req, *subreq;
 652         struct nb_packet_read_state *state;
 653
 654         req = tevent_req_create(mem_ctx, &state, struct nb_packet_read_state);
 655         if (req == NULL) {
 656                 return NULL;
 657         }
 658         subreq = read_packet_send(state, ev, reader->sock,
 659                                   sizeof(struct nb_packet_client_header),
 660                                   nb_packet_read_more, state);
 661         if (tevent_req_nomem(subreq, req)) {
 662                 return tevent_req_post(req, ev);
 663         }
 664         tevent_req_set_callback(subreq, nb_packet_read_done, req);
 665         return req;
 666 }
 667
 668 static ssize_t nb_packet_read_more(uint8_t *buf, size_t buflen, void *p)
 669 {
 670         struct nb_packet_read_state *state = talloc_get_type_abort(
 671                 p, struct nb_packet_read_state);
 672
 673         if (buflen > sizeof(struct nb_packet_client_header)) {
 674                 /*
 675                  * Been here, done
 676                  */
 677                 return 0;
 678         }
 679         memcpy(&state->hdr, buf, sizeof(struct nb_packet_client_header));
 680         return state->hdr.len;
 681 }
 682
 683 static void nb_packet_read_done(struct tevent_req *subreq)
 684 {
 685         struct tevent_req *req = tevent_req_callback_data(
 686                 subreq, struct tevent_req);
 687         struct nb_packet_read_state *state = tevent_req_data(
 688                 req, struct nb_packet_read_state);
 689         ssize_t nread;
 690         int err;
 691
 692         nread = read_packet_recv(subreq, state, &state->buf, &err);
 693         if (nread == -1) {
 694                 tevent_req_nterror(req, map_nt_error_from_unix(err));
 695                 return;
 696         }
 697         state->buflen = nread;
 698         tevent_req_done(req);
 699 }
 700
 701 NTSTATUS nb_packet_read_recv(struct tevent_req *req,
 702                              struct packet_struct **ppacket)
 703 {
 704         struct nb_packet_read_state *state = tevent_req_data(
 705                 req, struct nb_packet_read_state);
 706         struct nb_packet_client_header hdr;
 707         struct packet_struct *packet;
 708         NTSTATUS status;
 709
 710         if (tevent_req_is_nterror(req, &status)) {
 711                 return status;
 712         }
 713
 714         memcpy(&hdr, state->buf, sizeof(hdr));
 715
 716         packet = parse_packet(
 717                 (char *)state->buf + sizeof(struct nb_packet_client_header),
 718                 state->buflen - sizeof(struct nb_packet_client_header),
 719                 state->hdr.type, state->hdr.ip, state->hdr.port);
 720         if (packet == NULL) {
 721                 return NT_STATUS_INVALID_NETWORK_RESPONSE;
 722         }
 723         *ppacket = packet;
 724         return NT_STATUS_OK;
 725 }