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 "libsmb/unexpected.h"
  23 #include "../lib/util/tevent_ntstatus.h"
  24 #include "lib/util_tsock.h"
  25 #include "libsmb/nmblib.h"
  26 #include "lib/tsocket/tsocket.h"
  27 #include "lib/util/sys_rw.h"
  28
  29 struct nb_packet_query {
  30         enum packet_type type;
  31         size_t mailslot_namelen;
  32         int trn_id;
  33 };
  34
  35 struct nb_packet_client;
  36
  37 struct nb_packet_server {
  38         struct tevent_context *ev;
  39         int listen_sock;
  40         struct tevent_fd *listen_fde;
  41         int max_clients;
  42         int num_clients;
  43         struct nb_packet_client *clients;
  44 };
  45
  46 struct nb_packet_client {
  47         struct nb_packet_client *prev, *next;
  48         struct nb_packet_server *server;
  49
  50         enum packet_type type;
  51         int trn_id;
  52         char *mailslot_name;
  53
  54         struct {
  55                 uint8_t byte;
  56                 struct iovec iov[1];
  57         } ack;
  58
  59         struct tstream_context *sock;
  60         struct tevent_queue *out_queue;
  61 };
  62
  63 static int nb_packet_server_destructor(struct nb_packet_server *s);
  64 static void nb_packet_server_listener(struct tevent_context *ev,
  65                                       struct tevent_fd *fde,
  66                                       uint16_t flags,
  67                                       void *private_data);
  68
  69 NTSTATUS nb_packet_server_create(TALLOC_CTX *mem_ctx,
  70                                  struct tevent_context *ev,
  71                                  const char *nmbd_socket_dir,
  72                                  int max_clients,
  73                                  struct nb_packet_server **presult)
  74 {
  75         struct nb_packet_server *result;
  76         NTSTATUS status;
  77         int rc;
  78
  79         result = talloc_zero(mem_ctx, struct nb_packet_server);
  80         if (result == NULL) {
  81                 status = NT_STATUS_NO_MEMORY;
  82                 goto fail;
  83         }
  84         result->ev = ev;
  85         result->max_clients = max_clients;
  86
  87         result->listen_sock = create_pipe_sock(
  88                 nmbd_socket_dir, "unexpected", 0755);
  89         if (result->listen_sock == -1) {
  90                 status = map_nt_error_from_unix(errno);
  91                 goto fail;
  92         }
  93         rc = listen(result->listen_sock, 5);
  94         if (rc < 0) {
  95                 status = map_nt_error_from_unix(errno);
  96                 goto fail;
  97         }
  98         talloc_set_destructor(result, nb_packet_server_destructor);
  99
 100         result->listen_fde = tevent_add_fd(ev, result,
 101                                            result->listen_sock,
 102                                            TEVENT_FD_READ,
 103                                            nb_packet_server_listener,
 104                                            result);
 105         if (result->listen_fde == NULL) {
 106                 status = NT_STATUS_NO_MEMORY;
 107                 goto fail;
 108         }
 109
 110         *presult = result;
 111         return NT_STATUS_OK;
 112 fail:
 113         TALLOC_FREE(result);
 114         return status;
 115 }
 116
 117 static int nb_packet_server_destructor(struct nb_packet_server *s)
 118 {
 119         TALLOC_FREE(s->listen_fde);
 120
 121         if (s->listen_sock != -1) {
 122                 close(s->listen_sock);
 123                 s->listen_sock = -1;
 124         }
 125         return 0;
 126 }
 127
 128 static int nb_packet_client_destructor(struct nb_packet_client *c);
 129 static ssize_t nb_packet_client_more(uint8_t *buf, size_t buflen,
 130                                      void *private_data);
 131 static void nb_packet_got_query(struct tevent_req *req);
 132 static void nb_packet_client_ack_done(struct tevent_req *req);
 133 static void nb_packet_client_read_done(struct tevent_req *req);
 134
 135 static void nb_packet_server_listener(struct tevent_context *ev,
 136                                       struct tevent_fd *fde,
 137                                       uint16_t flags,
 138                                       void *private_data)
 139 {
 140         struct nb_packet_server *server = talloc_get_type_abort(
 141                 private_data, struct nb_packet_server);
 142         struct nb_packet_client *client;
 143         struct tevent_req *req;
 144         struct sockaddr_un sunaddr;
 145         socklen_t len;
 146         int sock;
 147         int ret;
 148
 149         len = sizeof(sunaddr);
 150
 151         sock = accept(server->listen_sock, (struct sockaddr *)(void *)&sunaddr,
 152                       &len);
 153         if (sock == -1) {
 154                 return;
 155         }
 156         smb_set_close_on_exec(sock);
 157         DEBUG(6,("accepted socket %d\n", sock));
 158
 159         client = talloc_zero(server, struct nb_packet_client);
 160         if (client == NULL) {
 161                 DEBUG(10, ("talloc failed\n"));
 162                 close(sock);
 163                 return;
 164         }
 165         ret = tstream_bsd_existing_socket(client, sock, &client->sock);
 166         if (ret != 0) {
 167                 DEBUG(10, ("tstream_bsd_existing_socket failed\n"));
 168                 TALLOC_FREE(client);
 169                 close(sock);
 170                 return;
 171         }
 172         /* as server we want to fail early */
 173         tstream_bsd_fail_readv_first_error(client->sock, true);
 174
 175         client->server = server;
 176
 177         client->out_queue = tevent_queue_create(
 178                 client, "unexpected packet output");
 179         if (client->out_queue == NULL) {
 180                 DEBUG(10, ("tevent_queue_create failed\n"));
 181                 TALLOC_FREE(client);
 182                 return;
 183         }
 184
 185         req = tstream_read_packet_send(client, ev, client->sock,
 186                                        sizeof(struct nb_packet_query),
 187                                        nb_packet_client_more, NULL);
 188         if (req == NULL) {
 189                 DEBUG(10, ("tstream_read_packet_send failed\n"));
 190                 TALLOC_FREE(client);
 191                 return;
 192         }
 193         tevent_req_set_callback(req, nb_packet_got_query, client);
 194
 195         DLIST_ADD(server->clients, client);
 196         server->num_clients += 1;
 197
 198         talloc_set_destructor(client, nb_packet_client_destructor);
 199
 200         if (server->num_clients > server->max_clients) {
 201                 DEBUG(10, ("Too many clients, dropping oldest\n"));
 202
 203                 /*
 204                  * no TALLOC_FREE here, don't mess with the list structs
 205                  */
 206                 talloc_free(server->clients->prev);
 207         }
 208 }
 209
 210 static ssize_t nb_packet_client_more(uint8_t *buf, size_t buflen,
 211                                      void *private_data)
 212 {
 213         struct nb_packet_query q;
 214         if (buflen > sizeof(struct nb_packet_query)) {
 215                 return 0;
 216         }
 217         /* Take care of alignment */
 218         memcpy(&q, buf, sizeof(q));
 219         if (q.mailslot_namelen > 1024) {
 220                 DEBUG(10, ("Got invalid mailslot namelen %d\n",
 221                            (int)q.mailslot_namelen));
 222                 return -1;
 223         }
 224         return q.mailslot_namelen;
 225 }
 226
 227 static int nb_packet_client_destructor(struct nb_packet_client *c)
 228 {
 229         tevent_queue_stop(c->out_queue);
 230         TALLOC_FREE(c->sock);
 231
 232         DLIST_REMOVE(c->server->clients, c);
 233         c->server->num_clients -= 1;
 234         return 0;
 235 }
 236
 237 static void nb_packet_got_query(struct tevent_req *req)
 238 {
 239         struct nb_packet_client *client = tevent_req_callback_data(
 240                 req, struct nb_packet_client);
 241         struct nb_packet_query q;
 242         uint8_t *buf;
 243         ssize_t nread;
 244         int err;
 245
 246         nread = tstream_read_packet_recv(req, client, &buf, &err);
 247         TALLOC_FREE(req);
 248         if (nread < (ssize_t)sizeof(struct nb_packet_query)) {
 249                 DEBUG(10, ("read_packet_recv returned %d (%s)\n",
 250                            (int)nread,
 251                            (nread == -1) ? strerror(err) : "wrong length"));
 252                 TALLOC_FREE(client);
 253                 return;
 254         }
 255
 256         /* Take care of alignment */
 257         memcpy(&q, buf, sizeof(q));
 258
 259         if ((size_t)nread !=
 260             sizeof(struct nb_packet_query) + q.mailslot_namelen) {
 261                 DEBUG(10, ("nb_packet_got_query: Invalid mailslot namelength\n"));
 262                 TALLOC_FREE(client);
 263                 return;
 264         }
 265
 266         client->trn_id = q.trn_id;
 267         client->type = q.type;
 268         if (q.mailslot_namelen > 0) {
 269                 client->mailslot_name = talloc_strndup(
 270                         client, (char *)buf + sizeof(q),
 271                         q.mailslot_namelen);
 272                 if (client->mailslot_name == NULL) {
 273                         TALLOC_FREE(client);
 274                         return;
 275                 }
 276         }
 277
 278         TALLOC_FREE(buf);
 279
 280         client->ack.byte = 0;
 281         client->ack.iov[0].iov_base = &client->ack.byte;
 282         client->ack.iov[0].iov_len = 1;
 283         req = tstream_writev_queue_send(client, client->server->ev,
 284                                         client->sock,
 285                                         client->out_queue,
 286                                         client->ack.iov, 1);
 287         if (req == NULL) {
 288                 DEBUG(10, ("tstream_writev_queue_send failed\n"));
 289                 TALLOC_FREE(client);
 290                 return;
 291         }
 292         tevent_req_set_callback(req, nb_packet_client_ack_done, client);
 293
 294         req = tstream_read_packet_send(client, client->server->ev,
 295                                        client->sock, 1, NULL, NULL);
 296         if (req == NULL) {
 297                 DEBUG(10, ("Could not activate reader for client exit "
 298                            "detection\n"));
 299                 TALLOC_FREE(client);
 300                 return;
 301         }
 302         tevent_req_set_callback(req, nb_packet_client_read_done,
 303                                 client);
 304 }
 305
 306 static void nb_packet_client_ack_done(struct tevent_req *req)
 307 {
 308         struct nb_packet_client *client = tevent_req_callback_data(
 309                 req, struct nb_packet_client);
 310         ssize_t nwritten;
 311         int err;
 312
 313         nwritten = tstream_writev_queue_recv(req, &err);
 314
 315         TALLOC_FREE(req);
 316
 317         if (nwritten == -1) {
 318                 DEBUG(10, ("tstream_writev_queue_recv failed: %s\n",
 319                            strerror(err)));
 320                 TALLOC_FREE(client);
 321                 return;
 322         }
 323 }
 324
 325 static void nb_packet_client_read_done(struct tevent_req *req)
 326 {
 327         struct nb_packet_client *client = tevent_req_callback_data(
 328                 req, struct nb_packet_client);
 329         ssize_t nread;
 330         uint8_t *buf;
 331         int err;
 332
 333         nread = tstream_read_packet_recv(req, client, &buf, &err);
 334         TALLOC_FREE(req);
 335         if (nread == 1) {
 336                 DEBUG(10, ("Protocol error, received data on write-only "
 337                            "unexpected socket: 0x%2.2x\n", (*buf)));
 338         }
 339         TALLOC_FREE(client);
 340 }
 341
 342 static void nb_packet_client_send(struct nb_packet_client *client,
 343                                   struct packet_struct *p);
 344
 345 void nb_packet_dispatch(struct nb_packet_server *server,
 346                         struct packet_struct *p)
 347 {
 348         struct nb_packet_client *c;
 349         uint16_t trn_id;
 350
 351         switch (p->packet_type) {
 352         case NMB_PACKET:
 353                 trn_id = p->packet.nmb.header.name_trn_id;
 354                 break;
 355         case DGRAM_PACKET:
 356                 trn_id = p->packet.dgram.header.dgm_id;
 357                 break;
 358         default:
 359                 DEBUG(10, ("Got invalid packet type %d\n",
 360                            (int)p->packet_type));
 361                 return;
 362         }
 363         for (c = server->clients; c != NULL; c = c->next) {
 364
 365                 if (c->type != p->packet_type) {
 366                         DEBUG(10, ("client expects packet %d, got %d\n",
 367                                    c->type, p->packet_type));
 368                         continue;
 369                 }
 370
 371                 if (p->packet_type == NMB_PACKET) {
 372                         /*
 373                          * See if the client specified transaction
 374                          * ID. Filter if it did.
 375                          */
 376                         if ((c->trn_id != -1) &&
 377                             (c->trn_id != trn_id)) {
 378                                 DEBUG(10, ("client expects trn %d, got %d\n",
 379                                            c->trn_id, trn_id));
 380                                 continue;
 381                         }
 382                 } else {
 383                         /*
 384                          * See if the client specified a mailslot
 385                          * name. Filter if it did.
 386                          */
 387                         if ((c->mailslot_name != NULL) &&
 388                             !match_mailslot_name(p, c->mailslot_name)) {
 389                                 continue;
 390                         }
 391                 }
 392                 nb_packet_client_send(c, p);
 393         }
 394 }
 395
 396 struct nb_packet_client_header {
 397         size_t len;
 398         enum packet_type type;
 399         time_t timestamp;
 400         struct in_addr ip;
 401         int port;
 402 };
 403
 404 struct nb_packet_client_state {
 405         struct nb_packet_client *client;
 406         struct iovec iov[2];
 407         struct nb_packet_client_header hdr;
 408         char buf[1024];
 409 };
 410
 411 static void nb_packet_client_send_done(struct tevent_req *req);
 412
 413 static void nb_packet_client_send(struct nb_packet_client *client,
 414                                   struct packet_struct *p)
 415 {
 416         struct nb_packet_client_state *state;
 417         struct tevent_req *req;
 418
 419         if (tevent_queue_length(client->out_queue) > 10) {
 420                 /*
 421                  * Skip clients that don't listen anyway, some form of DoS
 422                  * protection
 423                  */
 424                 return;
 425         }
 426
 427         state = talloc_zero(client, struct nb_packet_client_state);
 428         if (state == NULL) {
 429                 DEBUG(10, ("talloc failed\n"));
 430                 return;
 431         }
 432
 433         state->client = client;
 434
 435         state->hdr.ip = p->ip;
 436         state->hdr.port = p->port;
 437         state->hdr.timestamp = p->timestamp;
 438         state->hdr.type = p->packet_type;
 439         state->hdr.len = build_packet(state->buf, sizeof(state->buf), p);
 440
 441         state->iov[0].iov_base = (char *)&state->hdr;
 442         state->iov[0].iov_len = sizeof(state->hdr);
 443         state->iov[1].iov_base = state->buf;
 444         state->iov[1].iov_len = state->hdr.len;
 445
 446         req = tstream_writev_queue_send(state, client->server->ev,
 447                                         client->sock,
 448                                         client->out_queue,
 449                                         state->iov, 2);
 450         if (req == NULL) {
 451                 DEBUG(10, ("tstream_writev_queue_send failed\n"));
 452                 return;
 453         }
 454         tevent_req_set_callback(req, nb_packet_client_send_done, state);
 455 }
 456
 457 static void nb_packet_client_send_done(struct tevent_req *req)
 458 {
 459         struct nb_packet_client_state *state = tevent_req_callback_data(
 460                 req, struct nb_packet_client_state);
 461         struct nb_packet_client *client = state->client;
 462         ssize_t nwritten;
 463         int err;
 464
 465         nwritten = tstream_writev_queue_recv(req, &err);
 466
 467         TALLOC_FREE(req);
 468         TALLOC_FREE(state);
 469
 470         if (nwritten == -1) {
 471                 DEBUG(10, ("tstream_writev_queue failed: %s\n", strerror(err)));
 472                 TALLOC_FREE(client);
 473                 return;
 474         }
 475 }
 476
 477 struct nb_packet_reader {
 478         struct tstream_context *sock;
 479 };
 480
 481 struct nb_packet_reader_state {
 482         struct tevent_context *ev;
 483         struct nb_packet_query query;
 484         const char *mailslot_name;
 485         struct iovec iov[2];
 486         struct nb_packet_reader *reader;
 487 };
 488
 489 static void nb_packet_reader_connected(struct tevent_req *subreq);
 490 static void nb_packet_reader_sent_query(struct tevent_req *subreq);
 491 static void nb_packet_reader_got_ack(struct tevent_req *subreq);
 492
 493 struct tevent_req *nb_packet_reader_send(TALLOC_CTX *mem_ctx,
 494                                          struct tevent_context *ev,
 495                                          const char *nmbd_socket_dir,
 496                                          enum packet_type type,
 497                                          int trn_id,
 498                                          const char *mailslot_name)
 499 {
 500         struct tevent_req *req, *subreq;
 501         struct nb_packet_reader_state *state;
 502         struct tsocket_address *laddr;
 503         char *rpath;
 504         struct tsocket_address *raddr;
 505         int ret;
 506
 507         req = tevent_req_create(mem_ctx, &state,
 508                                 struct nb_packet_reader_state);
 509         if (req == NULL) {
 510                 return NULL;
 511         }
 512         state->ev = ev;
 513         state->query.trn_id = trn_id;
 514         state->query.type = type;
 515         state->mailslot_name = mailslot_name;
 516
 517         if (mailslot_name != NULL) {
 518                 state->query.mailslot_namelen = strlen(mailslot_name);
 519         }
 520
 521         state->reader = talloc_zero(state, struct nb_packet_reader);
 522         if (tevent_req_nomem(state->reader, req)) {
 523                 return tevent_req_post(req, ev);
 524         }
 525
 526         ret = tsocket_address_unix_from_path(state, NULL, &laddr);
 527         if (ret != 0) {
 528                 tevent_req_nterror(req, map_nt_error_from_unix(errno));
 529                 return tevent_req_post(req, ev);
 530         }
 531         rpath = talloc_asprintf(state, "%s/%s", nmbd_socket_dir,
 532                                "unexpected");
 533         if (tevent_req_nomem(rpath, req)) {
 534                 return tevent_req_post(req, ev);
 535         }
 536         ret = tsocket_address_unix_from_path(state, rpath, &raddr);
 537         if (ret != 0) {
 538                 tevent_req_nterror(req, map_nt_error_from_unix(errno));
 539                 return tevent_req_post(req, ev);
 540         }
 541
 542         subreq = tstream_unix_connect_send(state, ev, laddr, raddr);
 543         if (tevent_req_nomem(subreq, req)) {
 544                 return tevent_req_post(req, ev);
 545         }
 546         tevent_req_set_callback(subreq, nb_packet_reader_connected, req);
 547         return req;
 548 }
 549
 550 static void nb_packet_reader_connected(struct tevent_req *subreq)
 551 {
 552         struct tevent_req *req = tevent_req_callback_data(
 553                 subreq, struct tevent_req);
 554         struct nb_packet_reader_state *state = tevent_req_data(
 555                 req, struct nb_packet_reader_state);
 556         int res, err;
 557         int num_iovecs = 1;
 558
 559         res = tstream_unix_connect_recv(subreq, &err, state->reader,
 560                                         &state->reader->sock);
 561         TALLOC_FREE(subreq);
 562         if (res == -1) {
 563                 DEBUG(10, ("tstream_unix_connect failed: %s\n", strerror(err)));
 564                 tevent_req_nterror(req, map_nt_error_from_unix(err));
 565                 return;
 566         }
 567
 568         state->iov[0].iov_base = (char *)&state->query;
 569         state->iov[0].iov_len = sizeof(state->query);
 570
 571         if (state->mailslot_name != NULL) {
 572                 num_iovecs = 2;
 573                 state->iov[1].iov_base = discard_const_p(
 574                         char, state->mailslot_name);
 575                 state->iov[1].iov_len = state->query.mailslot_namelen;
 576         }
 577
 578         subreq = tstream_writev_send(state, state->ev, state->reader->sock,
 579                                      state->iov, num_iovecs);
 580         if (tevent_req_nomem(subreq, req)) {
 581                 return;
 582         }
 583         tevent_req_set_callback(subreq, nb_packet_reader_sent_query, req);
 584 }
 585
 586 static void nb_packet_reader_sent_query(struct tevent_req *subreq)
 587 {
 588         struct tevent_req *req = tevent_req_callback_data(
 589                 subreq, struct tevent_req);
 590         struct nb_packet_reader_state *state = tevent_req_data(
 591                 req, struct nb_packet_reader_state);
 592         ssize_t written;
 593         int err;
 594
 595         written = tstream_writev_recv(subreq, &err);
 596         TALLOC_FREE(subreq);
 597         if (written == -1) {
 598                 tevent_req_nterror(req, map_nt_error_from_unix(err));
 599                 return;
 600         }
 601         if ((size_t)written !=
 602             sizeof(state->query) + state->query.mailslot_namelen) {
 603                 tevent_req_nterror(req, NT_STATUS_UNEXPECTED_IO_ERROR);
 604                 return;
 605         }
 606         subreq = tstream_read_packet_send(state, state->ev,
 607                                           state->reader->sock,
 608                                           1, NULL, NULL);
 609         if (tevent_req_nomem(subreq, req)) {
 610                 return;
 611         }
 612         tevent_req_set_callback(subreq, nb_packet_reader_got_ack, req);
 613 }
 614
 615 static void nb_packet_reader_got_ack(struct tevent_req *subreq)
 616 {
 617         struct tevent_req *req = tevent_req_callback_data(
 618                 subreq, struct tevent_req);
 619         struct nb_packet_reader_state *state = tevent_req_data(
 620                 req, struct nb_packet_reader_state);
 621         ssize_t nread;
 622         int err;
 623         uint8_t *buf;
 624
 625         nread = tstream_read_packet_recv(subreq, state, &buf, &err);
 626         TALLOC_FREE(subreq);
 627         if (nread == -1) {
 628                 DEBUG(10, ("read_packet_recv returned %s\n",
 629                            strerror(err)));
 630                 tevent_req_nterror(req, map_nt_error_from_unix(err));
 631                 return;
 632         }
 633         if (nread != 1) {
 634                 DBG_DEBUG("read = %zd, expected 1\n", nread);
 635                 tevent_req_nterror(req, NT_STATUS_UNEXPECTED_IO_ERROR);
 636                 return;
 637         }
 638         tevent_req_done(req);
 639 }
 640
 641 NTSTATUS nb_packet_reader_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 642                                struct nb_packet_reader **preader)
 643 {
 644         struct nb_packet_reader_state *state = tevent_req_data(
 645                 req, struct nb_packet_reader_state);
 646         NTSTATUS status;
 647
 648         if (tevent_req_is_nterror(req, &status)) {
 649                 tevent_req_received(req);
 650                 return status;
 651         }
 652         *preader = talloc_move(mem_ctx, &state->reader);
 653         tevent_req_received(req);
 654         return NT_STATUS_OK;
 655 }
 656
 657 struct nb_packet_read_state {
 658         struct nb_packet_client_header hdr;
 659         uint8_t *buf;
 660         size_t buflen;
 661 };
 662
 663 static ssize_t nb_packet_read_more(uint8_t *buf, size_t buflen, void *p);
 664 static void nb_packet_read_done(struct tevent_req *subreq);
 665
 666 struct tevent_req *nb_packet_read_send(TALLOC_CTX *mem_ctx,
 667                                        struct tevent_context *ev,
 668                                        struct nb_packet_reader *reader)
 669 {
 670         struct tevent_req *req, *subreq;
 671         struct nb_packet_read_state *state;
 672
 673         req = tevent_req_create(mem_ctx, &state, struct nb_packet_read_state);
 674         if (req == NULL) {
 675                 return NULL;
 676         }
 677         subreq = tstream_read_packet_send(state, ev, reader->sock,
 678                                           sizeof(struct nb_packet_client_header),
 679                                           nb_packet_read_more, state);
 680         if (tevent_req_nomem(subreq, req)) {
 681                 return tevent_req_post(req, ev);
 682         }
 683         tevent_req_set_callback(subreq, nb_packet_read_done, req);
 684         return req;
 685 }
 686
 687 static ssize_t nb_packet_read_more(uint8_t *buf, size_t buflen, void *p)
 688 {
 689         struct nb_packet_read_state *state = talloc_get_type_abort(
 690                 p, struct nb_packet_read_state);
 691
 692         if (buflen > sizeof(struct nb_packet_client_header)) {
 693                 /*
 694                  * Been here, done
 695                  */
 696                 return 0;
 697         }
 698         memcpy(&state->hdr, buf, sizeof(struct nb_packet_client_header));
 699         return state->hdr.len;
 700 }
 701
 702 static void nb_packet_read_done(struct tevent_req *subreq)
 703 {
 704         struct tevent_req *req = tevent_req_callback_data(
 705                 subreq, struct tevent_req);
 706         struct nb_packet_read_state *state = tevent_req_data(
 707                 req, struct nb_packet_read_state);
 708         ssize_t nread;
 709         int err;
 710
 711         nread = tstream_read_packet_recv(subreq, state, &state->buf, &err);
 712         if (nread == -1) {
 713                 tevent_req_nterror(req, map_nt_error_from_unix(err));
 714                 return;
 715         }
 716         state->buflen = nread;
 717         tevent_req_done(req);
 718 }
 719
 720 NTSTATUS nb_packet_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 721                              struct packet_struct **ppacket)
 722 {
 723         struct nb_packet_read_state *state = tevent_req_data(
 724                 req, struct nb_packet_read_state);
 725         struct nb_packet_client_header hdr;
 726         struct packet_struct *packet;
 727         NTSTATUS status;
 728
 729         if (tevent_req_is_nterror(req, &status)) {
 730                 tevent_req_received(req);
 731                 return status;
 732         }
 733
 734         memcpy(&hdr, state->buf, sizeof(hdr));
 735
 736         packet = parse_packet_talloc(
 737                 mem_ctx,
 738                 (char *)state->buf + sizeof(struct nb_packet_client_header),
 739                 state->buflen - sizeof(struct nb_packet_client_header),
 740                 state->hdr.type, state->hdr.ip, state->hdr.port);
 741         if (packet == NULL) {
 742                 tevent_req_received(req);
 743                 return NT_STATUS_INVALID_NETWORK_RESPONSE;
 744         }
 745
 746         *ppacket = packet;
 747         tevent_req_received(req);
 748         return NT_STATUS_OK;
 749 }