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/util_tsock.h"
  24 #include "lib/tsocket/tsocket.h"
  25 #include "libsmb/nmblib.h"
  26 #include "lib/util/sys_rw.h"
  27
  28 static const char *nmbd_socket_dir(void)
  29 {
  30         return lp_parm_const_string(-1, "nmbd", "socket dir",
  31                                     get_dyn_NMBDSOCKETDIR());
  32 }
  33
  34 struct nb_packet_query {
  35         enum packet_type type;
  36         size_t mailslot_namelen;
  37         int trn_id;
  38 };
  39
  40 struct nb_packet_client;
  41
  42 struct nb_packet_server {
  43         struct tevent_context *ev;
  44         int listen_sock;
  45         struct tevent_fd *listen_fde;
  46         int max_clients;
  47         int num_clients;
  48         struct nb_packet_client *clients;
  49 };
  50
  51 struct nb_packet_client {
  52         struct nb_packet_client *prev, *next;
  53         struct nb_packet_server *server;
  54
  55         enum packet_type type;
  56         int trn_id;
  57         char *mailslot_name;
  58
  59         struct {
  60                 uint8_t byte;
  61                 struct iovec iov[1];
  62         } ack;
  63
  64         struct tstream_context *sock;
  65         struct tevent_queue *out_queue;
  66 };
  67
  68 static int nb_packet_server_destructor(struct nb_packet_server *s);
  69 static void nb_packet_server_listener(struct tevent_context *ev,
  70                                       struct tevent_fd *fde,
  71                                       uint16_t flags,
  72                                       void *private_data);
  73
  74 NTSTATUS nb_packet_server_create(TALLOC_CTX *mem_ctx,
  75                                  struct tevent_context *ev,
  76                                  int max_clients,
  77                                  struct nb_packet_server **presult)
  78 {
  79         struct nb_packet_server *result;
  80         NTSTATUS status;
  81         int rc;
  82
  83         result = talloc_zero(mem_ctx, struct nb_packet_server);
  84         if (result == NULL) {
  85                 status = NT_STATUS_NO_MEMORY;
  86                 goto fail;
  87         }
  88         result->ev = ev;
  89         result->max_clients = max_clients;
  90
  91         result->listen_sock = create_pipe_sock(
  92                 nmbd_socket_dir(), "unexpected", 0755);
  93         if (result->listen_sock == -1) {
  94                 status = map_nt_error_from_unix(errno);
  95                 goto fail;
  96         }
  97         rc = listen(result->listen_sock, 5);
  98         if (rc < 0) {
  99                 status = map_nt_error_from_unix(errno);
 100                 goto fail;
 101         }
 102         talloc_set_destructor(result, nb_packet_server_destructor);
 103
 104         result->listen_fde = tevent_add_fd(ev, result,
 105                                            result->listen_sock,
 106                                            TEVENT_FD_READ,
 107                                            nb_packet_server_listener,
 108                                            result);
 109         if (result->listen_fde == NULL) {
 110                 status = NT_STATUS_NO_MEMORY;
 111                 goto fail;
 112         }
 113
 114         *presult = result;
 115         return NT_STATUS_OK;
 116 fail:
 117         TALLOC_FREE(result);
 118         return status;
 119 }
 120
 121 static int nb_packet_server_destructor(struct nb_packet_server *s)
 122 {
 123         TALLOC_FREE(s->listen_fde);
 124
 125         if (s->listen_sock != -1) {
 126                 close(s->listen_sock);
 127                 s->listen_sock = -1;
 128         }
 129         return 0;
 130 }
 131
 132 static int nb_packet_client_destructor(struct nb_packet_client *c);
 133 static ssize_t nb_packet_client_more(uint8_t *buf, size_t buflen,
 134                                      void *private_data);
 135 static void nb_packet_got_query(struct tevent_req *req);
 136 static void nb_packet_client_ack_done(struct tevent_req *req);
 137 static void nb_packet_client_read_done(struct tevent_req *req);
 138
 139 static void nb_packet_server_listener(struct tevent_context *ev,
 140                                       struct tevent_fd *fde,
 141                                       uint16_t flags,
 142                                       void *private_data)
 143 {
 144         struct nb_packet_server *server = talloc_get_type_abort(
 145                 private_data, struct nb_packet_server);
 146         struct nb_packet_client *client;
 147         struct tevent_req *req;
 148         struct sockaddr_un sunaddr;
 149         socklen_t len;
 150         int sock;
 151         int ret;
 152
 153         len = sizeof(sunaddr);
 154
 155         sock = accept(server->listen_sock, (struct sockaddr *)(void *)&sunaddr,
 156                       &len);
 157         if (sock == -1) {
 158                 return;
 159         }
 160         DEBUG(6,("accepted socket %d\n", sock));
 161
 162         client = talloc_zero(server, struct nb_packet_client);
 163         if (client == NULL) {
 164                 DEBUG(10, ("talloc failed\n"));
 165                 close(sock);
 166                 return;
 167         }
 168         ret = tstream_bsd_existing_socket(client, sock, &client->sock);
 169         if (ret != 0) {
 170                 DEBUG(10, ("tstream_bsd_existing_socket failed\n"));
 171                 close(sock);
 172                 return;
 173         }
 174
 175         client->server = server;
 176         talloc_set_destructor(client, nb_packet_client_destructor);
 177
 178         client->out_queue = tevent_queue_create(
 179                 client, "unexpected packet output");
 180         if (client->out_queue == NULL) {
 181                 DEBUG(10, ("tevent_queue_create failed\n"));
 182                 TALLOC_FREE(client);
 183                 return;
 184         }
 185
 186         req = tstream_read_packet_send(client, ev, client->sock,
 187                                        sizeof(struct nb_packet_query),
 188                                        nb_packet_client_more, NULL);
 189         if (req == NULL) {
 190                 DEBUG(10, ("tstream_read_packet_send failed\n"));
 191                 TALLOC_FREE(client);
 192                 return;
 193         }
 194         tevent_req_set_callback(req, nb_packet_got_query, client);
 195
 196         DLIST_ADD(server->clients, client);
 197         server->num_clients += 1;
 198
 199         if (server->num_clients > server->max_clients) {
 200                 DEBUG(10, ("Too many clients, dropping oldest\n"));
 201
 202                 /*
 203                  * no TALLOC_FREE here, don't mess with the list structs
 204                  */
 205                 talloc_free(server->clients->prev);
 206         }
 207 }
 208
 209 static ssize_t nb_packet_client_more(uint8_t *buf, size_t buflen,
 210                                      void *private_data)
 211 {
 212         struct nb_packet_query q;
 213         if (buflen > sizeof(struct nb_packet_query)) {
 214                 return 0;
 215         }
 216         /* Take care of alignment */
 217         memcpy(&q, buf, sizeof(q));
 218         if (q.mailslot_namelen > 1024) {
 219                 DEBUG(10, ("Got invalid mailslot namelen %d\n",
 220                            (int)q.mailslot_namelen));
 221                 return -1;
 222         }
 223         return q.mailslot_namelen;
 224 }
 225
 226 static int nb_packet_client_destructor(struct nb_packet_client *c)
 227 {
 228         tevent_queue_stop(c->out_queue);
 229         TALLOC_FREE(c->sock);
 230
 231         DLIST_REMOVE(c->server->clients, c);
 232         c->server->num_clients -= 1;
 233         return 0;
 234 }
 235
 236 static void nb_packet_got_query(struct tevent_req *req)
 237 {
 238         struct nb_packet_client *client = tevent_req_callback_data(
 239                 req, struct nb_packet_client);
 240         struct nb_packet_query q;
 241         uint8_t *buf;
 242         ssize_t nread;
 243         int err;
 244
 245         nread = tstream_read_packet_recv(req, talloc_tos(), &buf, &err);
 246         TALLOC_FREE(req);
 247         if (nread < (ssize_t)sizeof(struct nb_packet_query)) {
 248                 DEBUG(10, ("read_packet_recv returned %d (%s)\n",
 249                            (int)nread,
 250                            (nread == -1) ? strerror(err) : "wrong length"));
 251                 TALLOC_FREE(client);
 252                 return;
 253         }
 254
 255         /* Take care of alignment */
 256         memcpy(&q, buf, sizeof(q));
 257
 258         if (nread != sizeof(struct nb_packet_query) + q.mailslot_namelen) {
 259                 DEBUG(10, ("nb_packet_got_query: Invalid mailslot namelength\n"));
 260                 TALLOC_FREE(client);
 261                 return;
 262         }
 263
 264         client->trn_id = q.trn_id;
 265         client->type = q.type;
 266         if (q.mailslot_namelen > 0) {
 267                 client->mailslot_name = talloc_strndup(
 268                         client, (char *)buf + sizeof(q),
 269                         q.mailslot_namelen);
 270                 if (client->mailslot_name == NULL) {
 271                         TALLOC_FREE(client);
 272                         return;
 273                 }
 274         }
 275
 276         client->ack.byte = 0;
 277         client->ack.iov[0].iov_base = &client->ack.byte;
 278         client->ack.iov[0].iov_len = 1;
 279         req = tstream_writev_queue_send(client, client->server->ev,
 280                                         client->sock,
 281                                         client->out_queue,
 282                                         client->ack.iov, 1);
 283         if (req == NULL) {
 284                 DEBUG(10, ("tstream_writev_queue_send failed\n"));
 285                 TALLOC_FREE(client);
 286                 return;
 287         }
 288         tevent_req_set_callback(req, nb_packet_client_ack_done, client);
 289
 290         req = tstream_read_packet_send(client, client->server->ev,
 291                                        client->sock, 1, NULL, NULL);
 292         if (req == NULL) {
 293                 DEBUG(10, ("Could not activate reader for client exit "
 294                            "detection\n"));
 295                 TALLOC_FREE(client);
 296                 return;
 297         }
 298         tevent_req_set_callback(req, nb_packet_client_read_done,
 299                                 client);
 300 }
 301
 302 static void nb_packet_client_ack_done(struct tevent_req *req)
 303 {
 304         struct nb_packet_client *client = tevent_req_callback_data(
 305                 req, struct nb_packet_client);
 306         ssize_t nwritten;
 307         int err;
 308
 309         nwritten = tstream_writev_queue_recv(req, &err);
 310
 311         TALLOC_FREE(req);
 312
 313         if (nwritten == -1) {
 314                 DEBUG(10, ("tstream_writev_queue_recv failed: %s\n",
 315                            strerror(err)));
 316                 TALLOC_FREE(client);
 317                 return;
 318         }
 319 }
 320
 321 static void nb_packet_client_read_done(struct tevent_req *req)
 322 {
 323         struct nb_packet_client *client = tevent_req_callback_data(
 324                 req, struct nb_packet_client);
 325         ssize_t nread;
 326         uint8_t *buf;
 327         int err;
 328
 329         nread = tstream_read_packet_recv(req, talloc_tos(), &buf, &err);
 330         TALLOC_FREE(req);
 331         if (nread == 1) {
 332                 DEBUG(10, ("Protocol error, received data on write-only "
 333                            "unexpected socket: 0x%2.2x\n", (*buf)));
 334         }
 335         TALLOC_FREE(client);
 336 }
 337
 338 static void nb_packet_client_send(struct nb_packet_client *client,
 339                                   struct packet_struct *p);
 340
 341 void nb_packet_dispatch(struct nb_packet_server *server,
 342                         struct packet_struct *p)
 343 {
 344         struct nb_packet_client *c;
 345         uint16_t trn_id;
 346
 347         switch (p->packet_type) {
 348         case NMB_PACKET:
 349                 trn_id = p->packet.nmb.header.name_trn_id;
 350                 break;
 351         case DGRAM_PACKET:
 352                 trn_id = p->packet.dgram.header.dgm_id;
 353                 break;
 354         default:
 355                 DEBUG(10, ("Got invalid packet type %d\n",
 356                            (int)p->packet_type));
 357                 return;
 358         }
 359         for (c = server->clients; c != NULL; c = c->next) {
 360
 361                 if (c->type != p->packet_type) {
 362                         DEBUG(10, ("client expects packet %d, got %d\n",
 363                                    c->type, p->packet_type));
 364                         continue;
 365                 }
 366
 367                 if (p->packet_type == NMB_PACKET) {
 368                         /*
 369                          * See if the client specified transaction
 370                          * ID. Filter if it did.
 371                          */
 372                         if ((c->trn_id != -1) &&
 373                             (c->trn_id != trn_id)) {
 374                                 DEBUG(10, ("client expects trn %d, got %d\n",
 375                                            c->trn_id, trn_id));
 376                                 continue;
 377                         }
 378                 } else {
 379                         /*
 380                          * See if the client specified a mailslot
 381                          * name. Filter if it did.
 382                          */
 383                         if ((c->mailslot_name != NULL) &&
 384                             !match_mailslot_name(p, c->mailslot_name)) {
 385                                 continue;
 386                         }
 387                 }
 388                 nb_packet_client_send(c, p);
 389         }
 390 }
 391
 392 struct nb_packet_client_header {
 393         size_t len;
 394         enum packet_type type;
 395         time_t timestamp;
 396         struct in_addr ip;
 397         int port;
 398 };
 399
 400 struct nb_packet_client_state {
 401         struct nb_packet_client *client;
 402         struct iovec iov[2];
 403         struct nb_packet_client_header hdr;
 404         char buf[1024];
 405 };
 406
 407 static void nb_packet_client_send_done(struct tevent_req *req);
 408
 409 static void nb_packet_client_send(struct nb_packet_client *client,
 410                                   struct packet_struct *p)
 411 {
 412         struct nb_packet_client_state *state;
 413         struct tevent_req *req;
 414
 415         if (tevent_queue_length(client->out_queue) > 10) {
 416                 /*
 417                  * Skip clients that don't listen anyway, some form of DoS
 418                  * protection
 419                  */
 420                 return;
 421         }
 422
 423         state = talloc_zero(client, struct nb_packet_client_state);
 424         if (state == NULL) {
 425                 DEBUG(10, ("talloc failed\n"));
 426                 return;
 427         }
 428
 429         state->client = client;
 430
 431         state->hdr.ip = p->ip;
 432         state->hdr.port = p->port;
 433         state->hdr.timestamp = p->timestamp;
 434         state->hdr.type = p->packet_type;
 435         state->hdr.len = build_packet(state->buf, sizeof(state->buf), p);
 436
 437         state->iov[0].iov_base = (char *)&state->hdr;
 438         state->iov[0].iov_len = sizeof(state->hdr);
 439         state->iov[1].iov_base = state->buf;
 440         state->iov[1].iov_len = state->hdr.len;
 441
 442         req = tstream_writev_queue_send(state, client->server->ev,
 443                                         client->sock,
 444                                         client->out_queue,
 445                                         state->iov, 2);
 446         if (req == NULL) {
 447                 DEBUG(10, ("tstream_writev_queue_send failed\n"));
 448                 return;
 449         }
 450         tevent_req_set_callback(req, nb_packet_client_send_done, state);
 451 }
 452
 453 static void nb_packet_client_send_done(struct tevent_req *req)
 454 {
 455         struct nb_packet_client_state *state = tevent_req_callback_data(
 456                 req, struct nb_packet_client_state);
 457         struct nb_packet_client *client = state->client;
 458         ssize_t nwritten;
 459         int err;
 460
 461         nwritten = tstream_writev_queue_recv(req, &err);
 462
 463         TALLOC_FREE(req);
 464         TALLOC_FREE(state);
 465
 466         if (nwritten == -1) {
 467                 DEBUG(10, ("tstream_writev_queue failed: %s\n", strerror(err)));
 468                 TALLOC_FREE(client);
 469                 return;
 470         }
 471 }
 472
 473 struct nb_packet_reader {
 474         struct tstream_context *sock;
 475 };
 476
 477 struct nb_packet_reader_state {
 478         struct tevent_context *ev;
 479         struct nb_packet_query query;
 480         const char *mailslot_name;
 481         struct iovec iov[2];
 482         char c;
 483         struct nb_packet_reader *reader;
 484 };
 485
 486 static void nb_packet_reader_connected(struct tevent_req *subreq);
 487 static void nb_packet_reader_sent_query(struct tevent_req *subreq);
 488 static void nb_packet_reader_got_ack(struct tevent_req *subreq);
 489
 490 struct tevent_req *nb_packet_reader_send(TALLOC_CTX *mem_ctx,
 491                                          struct tevent_context *ev,
 492                                          enum packet_type type,
 493                                          int trn_id,
 494                                          const char *mailslot_name)
 495 {
 496         struct tevent_req *req, *subreq;
 497         struct nb_packet_reader_state *state;
 498         struct tsocket_address *laddr;
 499         char *rpath;
 500         struct tsocket_address *raddr;
 501         int ret;
 502
 503         req = tevent_req_create(mem_ctx, &state,
 504                                 struct nb_packet_reader_state);
 505         if (req == NULL) {
 506                 return NULL;
 507         }
 508         state->ev = ev;
 509         state->query.trn_id = trn_id;
 510         state->query.type = type;
 511         state->mailslot_name = mailslot_name;
 512
 513         if (mailslot_name != NULL) {
 514                 state->query.mailslot_namelen = strlen(mailslot_name);
 515         }
 516
 517         state->reader = talloc_zero(state, struct nb_packet_reader);
 518         if (tevent_req_nomem(state->reader, req)) {
 519                 return tevent_req_post(req, ev);
 520         }
 521
 522         ret = tsocket_address_unix_from_path(state, "", &laddr);
 523         if (ret != 0) {
 524                 tevent_req_nterror(req, map_nt_error_from_unix(errno));
 525                 return tevent_req_post(req, ev);
 526         }
 527         rpath = talloc_asprintf(state, "%s/%s", nmbd_socket_dir(),
 528                                "unexpected");
 529         if (tevent_req_nomem(rpath, req)) {
 530                 return tevent_req_post(req, ev);
 531         }
 532         ret = tsocket_address_unix_from_path(state, rpath, &raddr);
 533         if (ret != 0) {
 534                 tevent_req_nterror(req, map_nt_error_from_unix(errno));
 535                 return tevent_req_post(req, ev);
 536         }
 537
 538         subreq = tstream_unix_connect_send(state, ev, laddr, raddr);
 539         if (tevent_req_nomem(subreq, req)) {
 540                 return tevent_req_post(req, ev);
 541         }
 542         tevent_req_set_callback(subreq, nb_packet_reader_connected, req);
 543         return req;
 544 }
 545
 546 static void nb_packet_reader_connected(struct tevent_req *subreq)
 547 {
 548         struct tevent_req *req = tevent_req_callback_data(
 549                 subreq, struct tevent_req);
 550         struct nb_packet_reader_state *state = tevent_req_data(
 551                 req, struct nb_packet_reader_state);
 552         int res, err;
 553         int num_iovecs = 1;
 554
 555         res = tstream_unix_connect_recv(subreq, &err, state->reader,
 556                                         &state->reader->sock);
 557         TALLOC_FREE(subreq);
 558         if (res == -1) {
 559                 DEBUG(10, ("tstream_unix_connect failed: %s\n", strerror(err)));
 560                 tevent_req_nterror(req, map_nt_error_from_unix(err));
 561                 return;
 562         }
 563
 564         state->iov[0].iov_base = (char *)&state->query;
 565         state->iov[0].iov_len = sizeof(state->query);
 566
 567         if (state->mailslot_name != NULL) {
 568                 num_iovecs = 2;
 569                 state->iov[1].iov_base = discard_const_p(
 570                         char, state->mailslot_name);
 571                 state->iov[1].iov_len = state->query.mailslot_namelen;
 572         }
 573
 574         subreq = tstream_writev_send(state, state->ev, state->reader->sock,
 575                                      state->iov, num_iovecs);
 576         if (tevent_req_nomem(subreq, req)) {
 577                 return;
 578         }
 579         tevent_req_set_callback(subreq, nb_packet_reader_sent_query, req);
 580 }
 581
 582 static void nb_packet_reader_sent_query(struct tevent_req *subreq)
 583 {
 584         struct tevent_req *req = tevent_req_callback_data(
 585                 subreq, struct tevent_req);
 586         struct nb_packet_reader_state *state = tevent_req_data(
 587                 req, struct nb_packet_reader_state);
 588         ssize_t written;
 589         int err;
 590
 591         written = tstream_writev_recv(subreq, &err);
 592         TALLOC_FREE(subreq);
 593         if (written == -1) {
 594                 tevent_req_nterror(req, map_nt_error_from_unix(err));
 595                 return;
 596         }
 597         if (written != sizeof(state->query) + state->query.mailslot_namelen) {
 598                 tevent_req_nterror(req, NT_STATUS_UNEXPECTED_IO_ERROR);
 599                 return;
 600         }
 601         subreq = tstream_read_packet_send(state, state->ev,
 602                                           state->reader->sock,
 603                                           sizeof(state->c), NULL, NULL);
 604         if (tevent_req_nomem(subreq, req)) {
 605                 return;
 606         }
 607         tevent_req_set_callback(subreq, nb_packet_reader_got_ack, req);
 608 }
 609
 610 static void nb_packet_reader_got_ack(struct tevent_req *subreq)
 611 {
 612         struct tevent_req *req = tevent_req_callback_data(
 613                 subreq, struct tevent_req);
 614         struct nb_packet_reader_state *state = tevent_req_data(
 615                 req, struct nb_packet_reader_state);
 616         ssize_t nread;
 617         int err;
 618         uint8_t *buf;
 619
 620         nread = tstream_read_packet_recv(subreq, state, &buf, &err);
 621         TALLOC_FREE(subreq);
 622         if (nread == -1) {
 623                 DEBUG(10, ("read_packet_recv returned %s\n",
 624                            strerror(err)));
 625                 tevent_req_nterror(req, map_nt_error_from_unix(err));
 626                 return;
 627         }
 628         if (nread != sizeof(state->c)) {
 629                 DEBUG(10, ("read = %d, expected %d\n", (int)nread,
 630                            (int)sizeof(state->c)));
 631                 tevent_req_nterror(req, NT_STATUS_UNEXPECTED_IO_ERROR);
 632                 return;
 633         }
 634         tevent_req_done(req);
 635 }
 636
 637 NTSTATUS nb_packet_reader_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 638                                struct nb_packet_reader **preader)
 639 {
 640         struct nb_packet_reader_state *state = tevent_req_data(
 641                 req, struct nb_packet_reader_state);
 642         NTSTATUS status;
 643
 644         if (tevent_req_is_nterror(req, &status)) {
 645                 tevent_req_received(req);
 646                 return status;
 647         }
 648         *preader = talloc_move(mem_ctx, &state->reader);
 649         tevent_req_received(req);
 650         return NT_STATUS_OK;
 651 }
 652
 653 struct nb_packet_read_state {
 654         struct nb_packet_client_header hdr;
 655         uint8_t *buf;
 656         size_t buflen;
 657 };
 658
 659 static ssize_t nb_packet_read_more(uint8_t *buf, size_t buflen, void *p);
 660 static void nb_packet_read_done(struct tevent_req *subreq);
 661
 662 struct tevent_req *nb_packet_read_send(TALLOC_CTX *mem_ctx,
 663                                        struct tevent_context *ev,
 664                                        struct nb_packet_reader *reader)
 665 {
 666         struct tevent_req *req, *subreq;
 667         struct nb_packet_read_state *state;
 668
 669         req = tevent_req_create(mem_ctx, &state, struct nb_packet_read_state);
 670         if (req == NULL) {
 671                 return NULL;
 672         }
 673         subreq = tstream_read_packet_send(state, ev, reader->sock,
 674                                           sizeof(struct nb_packet_client_header),
 675                                           nb_packet_read_more, state);
 676         if (tevent_req_nomem(subreq, req)) {
 677                 return tevent_req_post(req, ev);
 678         }
 679         tevent_req_set_callback(subreq, nb_packet_read_done, req);
 680         return req;
 681 }
 682
 683 static ssize_t nb_packet_read_more(uint8_t *buf, size_t buflen, void *p)
 684 {
 685         struct nb_packet_read_state *state = talloc_get_type_abort(
 686                 p, struct nb_packet_read_state);
 687
 688         if (buflen > sizeof(struct nb_packet_client_header)) {
 689                 /*
 690                  * Been here, done
 691                  */
 692                 return 0;
 693         }
 694         memcpy(&state->hdr, buf, sizeof(struct nb_packet_client_header));
 695         return state->hdr.len;
 696 }
 697
 698 static void nb_packet_read_done(struct tevent_req *subreq)
 699 {
 700         struct tevent_req *req = tevent_req_callback_data(
 701                 subreq, struct tevent_req);
 702         struct nb_packet_read_state *state = tevent_req_data(
 703                 req, struct nb_packet_read_state);
 704         ssize_t nread;
 705         int err;
 706
 707         nread = tstream_read_packet_recv(subreq, state, &state->buf, &err);
 708         if (nread == -1) {
 709                 tevent_req_nterror(req, map_nt_error_from_unix(err));
 710                 return;
 711         }
 712         state->buflen = nread;
 713         tevent_req_done(req);
 714 }
 715
 716 NTSTATUS nb_packet_read_recv(struct tevent_req *req,
 717                              struct packet_struct **ppacket)
 718 {
 719         struct nb_packet_read_state *state = tevent_req_data(
 720                 req, struct nb_packet_read_state);
 721         struct nb_packet_client_header hdr;
 722         struct packet_struct *packet;
 723         NTSTATUS status;
 724
 725         if (tevent_req_is_nterror(req, &status)) {
 726                 tevent_req_received(req);
 727                 return status;
 728         }
 729
 730         memcpy(&hdr, state->buf, sizeof(hdr));
 731
 732         packet = parse_packet(
 733                 (char *)state->buf + sizeof(struct nb_packet_client_header),
 734                 state->buflen - sizeof(struct nb_packet_client_header),
 735                 state->hdr.type, state->hdr.ip, state->hdr.port);
 736         if (packet == NULL) {
 737                 tevent_req_received(req);
 738                 return NT_STATUS_INVALID_NETWORK_RESPONSE;
 739         }
 740         *ppacket = packet;
 741         tevent_req_received(req);
 742         return NT_STATUS_OK;
 743 }