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