libcli/nbt/nbtsocket.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    low level socket handling for nbt requests
   5
   6    Copyright (C) Andrew Tridgell 2005
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "lib/events/events.h"
  24 #include "../lib/util/dlinklist.h"
  25 #include "../libcli/nbt/libnbt.h"
  26 #include "../libcli/nbt/nbt_proto.h"
  27 #include "lib/socket/socket.h"
  28 #include "librpc/gen_ndr/ndr_nbt.h"
  29 #include "param/param.h"
  30
  31 #define NBT_MAX_REPLIES 1000
  32
  33 /*
  34   destroy a pending request
  35 */
  36 static int nbt_name_request_destructor(struct nbt_name_request *req)
  37 {
  38         if (req->state == NBT_REQUEST_SEND) {
  39                 DLIST_REMOVE(req->nbtsock->send_queue, req);
  40         }
  41         if (req->state == NBT_REQUEST_WAIT) {
  42                 req->nbtsock->num_pending--;
  43         }
  44         if (req->name_trn_id != 0 && !req->is_reply) {
  45                 idr_remove(req->nbtsock->idr, req->name_trn_id);
  46                 req->name_trn_id = 0;
  47         }
  48         if (req->te) {
  49                 talloc_free(req->te);
  50                 req->te = NULL;
  51         }
  52         if (req->nbtsock->send_queue == NULL) {
  53                 TEVENT_FD_NOT_WRITEABLE(req->nbtsock->fde);
  54         }
  55         if (req->nbtsock->num_pending == 0 &&
  56             req->nbtsock->incoming.handler == NULL) {
  57                 TEVENT_FD_NOT_READABLE(req->nbtsock->fde);
  58         }
  59         return 0;
  60 }
  61
  62
  63 /*
  64   handle send events on a nbt name socket
  65 */
  66 static void nbt_name_socket_send(struct nbt_name_socket *nbtsock)
  67 {
  68         struct nbt_name_request *req = nbtsock->send_queue;
  69         TALLOC_CTX *tmp_ctx = talloc_new(nbtsock);
  70         NTSTATUS status;
  71
  72         while ((req = nbtsock->send_queue)) {
  73                 size_t len;
  74
  75                 len = req->encoded.length;
  76                 status = socket_sendto(nbtsock->sock, &req->encoded, &len,
  77                                        req->dest);
  78                 if (NT_STATUS_IS_ERR(status)) goto failed;
  79
  80                 if (!NT_STATUS_IS_OK(status)) {
  81                         talloc_free(tmp_ctx);
  82                         return;
  83                 }
  84
  85                 DLIST_REMOVE(nbtsock->send_queue, req);
  86                 req->state = NBT_REQUEST_WAIT;
  87                 if (req->is_reply) {
  88                         talloc_free(req);
  89                 } else {
  90                         TEVENT_FD_READABLE(nbtsock->fde);
  91                         nbtsock->num_pending++;
  92                 }
  93         }
  94
  95         TEVENT_FD_NOT_WRITEABLE(nbtsock->fde);
  96         talloc_free(tmp_ctx);
  97         return;
  98
  99 failed:
 100         DLIST_REMOVE(nbtsock->send_queue, req);
 101         nbt_name_request_destructor(req);
 102         req->status = status;
 103         req->state = NBT_REQUEST_ERROR;
 104         talloc_free(tmp_ctx);
 105         if (req->async.fn) {
 106                 req->async.fn(req);
 107         } else if (req->is_reply) {
 108                 talloc_free(req);
 109         }
 110         return;
 111 }
 112
 113
 114 /*
 115   handle a request timeout
 116 */
 117 static void nbt_name_socket_timeout(struct tevent_context *ev, struct tevent_timer *te,
 118                                     struct timeval t, void *private_data)
 119 {
 120         struct nbt_name_request *req = talloc_get_type(private_data,
 121                                                        struct nbt_name_request);
 122
 123         if (req->num_retries != 0) {
 124                 req->num_retries--;
 125                 req->te = tevent_add_timer(req->nbtsock->event_ctx, req,
 126                                            timeval_add(&t, req->timeout, 0),
 127                                            nbt_name_socket_timeout, req);
 128                 if (req->state != NBT_REQUEST_SEND) {
 129                         req->state = NBT_REQUEST_SEND;
 130                         DLIST_ADD_END(req->nbtsock->send_queue, req);
 131                 }
 132                 TEVENT_FD_WRITEABLE(req->nbtsock->fde);
 133                 return;
 134         }
 135
 136         nbt_name_request_destructor(req);
 137         if (req->num_replies == 0) {
 138                 req->state = NBT_REQUEST_TIMEOUT;
 139                 req->status = NT_STATUS_IO_TIMEOUT;
 140         } else {
 141                 req->state = NBT_REQUEST_DONE;
 142                 req->status = NT_STATUS_OK;
 143         }
 144         if (req->async.fn) {
 145                 req->async.fn(req);
 146         } else if (req->is_reply) {
 147                 talloc_free(req);
 148         }
 149 }
 150
 151
 152
 153 /**
 154   handle recv events on a nbt name socket
 155 */
 156 static void nbt_name_socket_recv(struct nbt_name_socket *nbtsock)
 157 {
 158         TALLOC_CTX *tmp_ctx = talloc_new(nbtsock);
 159         NTSTATUS status;
 160         enum ndr_err_code ndr_err;
 161         struct socket_address *src;
 162         DATA_BLOB blob;
 163         size_t nread, dsize;
 164         struct nbt_name_packet *packet;
 165         struct nbt_name_request *req;
 166
 167         status = socket_pending(nbtsock->sock, &dsize);
 168         if (!NT_STATUS_IS_OK(status)) {
 169                 talloc_free(tmp_ctx);
 170                 return;
 171         }
 172
 173         blob = data_blob_talloc(tmp_ctx, NULL, dsize);
 174         if (blob.data == NULL) {
 175                 talloc_free(tmp_ctx);
 176                 return;
 177         }
 178
 179         status = socket_recvfrom(nbtsock->sock, blob.data, blob.length, &nread,
 180                                  tmp_ctx, &src);
 181         if (!NT_STATUS_IS_OK(status)) {
 182                 talloc_free(tmp_ctx);
 183                 return;
 184         }
 185
 186         packet = talloc(tmp_ctx, struct nbt_name_packet);
 187         if (packet == NULL) {
 188                 talloc_free(tmp_ctx);
 189                 return;
 190         }
 191
 192         /* parse the request */
 193         ndr_err = ndr_pull_struct_blob(&blob, packet, packet,
 194                                        (ndr_pull_flags_fn_t)ndr_pull_nbt_name_packet);
 195         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 196                 status = ndr_map_error2ntstatus(ndr_err);
 197                 DEBUG(2,("Failed to parse incoming NBT name packet - %s\n",
 198                          nt_errstr(status)));
 199                 talloc_free(tmp_ctx);
 200                 return;
 201         }
 202
 203         if (DEBUGLVL(10)) {
 204                 DEBUG(10,("Received nbt packet of length %d from %s:%d\n",
 205                           (int)blob.length, src->addr, src->port));
 206                 NDR_PRINT_DEBUG(nbt_name_packet, packet);
 207         }
 208
 209         /* if its not a reply then pass it off to the incoming request
 210            handler, if any */
 211         if (!(packet->operation & NBT_FLAG_REPLY)) {
 212                 if (nbtsock->incoming.handler) {
 213                         nbtsock->incoming.handler(nbtsock, packet, src);
 214                 }
 215                 talloc_free(tmp_ctx);
 216                 return;
 217         }
 218
 219         /* find the matching request */
 220         req = (struct nbt_name_request *)idr_find(nbtsock->idr,
 221                                                   packet->name_trn_id);
 222         if (req == NULL) {
 223                 if (nbtsock->unexpected.handler) {
 224                         nbtsock->unexpected.handler(nbtsock, packet, src);
 225                 } else {
 226                         DEBUG(10,("Failed to match request for incoming name packet id 0x%04x on %p\n",
 227                                  packet->name_trn_id, nbtsock));
 228                 }
 229                 talloc_free(tmp_ctx);
 230                 return;
 231         }
 232
 233         talloc_steal(req, packet);
 234         talloc_steal(req, src);
 235         talloc_free(tmp_ctx);
 236         nbt_name_socket_handle_response_packet(req, packet, src);
 237 }
 238
 239 void nbt_name_socket_handle_response_packet(struct nbt_name_request *req,
 240                                             struct nbt_name_packet *packet,
 241                                             struct socket_address *src)
 242 {
 243         /* if this is a WACK response, this we need to go back to waiting,
 244            but perhaps increase the timeout */
 245         if ((packet->operation & NBT_OPCODE) == NBT_OPCODE_WACK) {
 246                 uint32_t ttl;
 247                 if (req->received_wack || packet->ancount < 1) {
 248                         nbt_name_request_destructor(req);
 249                         req->status = NT_STATUS_INVALID_NETWORK_RESPONSE;
 250                         req->state  = NBT_REQUEST_ERROR;
 251                         goto done;
 252                 }
 253                 talloc_free(req->te);
 254                 /* we know we won't need any more retries - the server
 255                    has received our request */
 256                 req->num_retries   = 0;
 257                 req->received_wack = true;
 258                 /*
 259                  * there is a timeout in the packet,
 260                  * it is 5 + 4 * num_old_addresses
 261                  *
 262                  * although w2k3 screws it up
 263                  * and uses num_old_addresses = 0
 264                  *
 265                  * so we better fallback to the maximum
 266                  * of num_old_addresses = 25 if we got
 267                  * a timeout of less than 9s (5 + 4*1)
 268                  * or more than 105s (5 + 4*25).
 269                  */
 270                 ttl = packet->answers[0].ttl;
 271                 if ((ttl < (5 + 4*1)) || (ttl > (5 + 4*25))) {
 272                         ttl = 5 + 4*25;
 273                 }
 274                 req->timeout = ttl;
 275                 req->te = tevent_add_timer(req->nbtsock->event_ctx, req,
 276                                            timeval_current_ofs(req->timeout, 0),
 277                                            nbt_name_socket_timeout, req);
 278                 return;
 279         }
 280
 281
 282         req->replies = talloc_realloc(req, req->replies, struct nbt_name_reply, req->num_replies+1);
 283         if (req->replies == NULL) {
 284                 nbt_name_request_destructor(req);
 285                 req->state  = NBT_REQUEST_ERROR;
 286                 req->status = NT_STATUS_NO_MEMORY;
 287                 goto done;
 288         }
 289
 290         talloc_steal(req, src);
 291         req->replies[req->num_replies].dest   = src;
 292         talloc_steal(req, packet);
 293         req->replies[req->num_replies].packet = packet;
 294         req->num_replies++;
 295
 296         /* if we don't want multiple replies then we are done */
 297         if (req->allow_multiple_replies &&
 298             req->num_replies < NBT_MAX_REPLIES) {
 299                 return;
 300         }
 301
 302         nbt_name_request_destructor(req);
 303         req->state  = NBT_REQUEST_DONE;
 304         req->status = NT_STATUS_OK;
 305
 306 done:
 307         if (req->async.fn) {
 308                 req->async.fn(req);
 309         }
 310 }
 311
 312 /*
 313   handle fd events on a nbt_name_socket
 314 */
 315 static void nbt_name_socket_handler(struct tevent_context *ev, struct tevent_fd *fde,
 316                                     uint16_t flags, void *private_data)
 317 {
 318         struct nbt_name_socket *nbtsock = talloc_get_type(private_data,
 319                                                           struct nbt_name_socket);
 320         if (flags & TEVENT_FD_WRITE) {
 321                 nbt_name_socket_send(nbtsock);
 322         }
 323         if (flags & TEVENT_FD_READ) {
 324                 nbt_name_socket_recv(nbtsock);
 325         }
 326 }
 327
 328
 329 /*
 330   initialise a nbt_name_socket. The event_ctx is optional, if provided
 331   then operations will use that event context
 332 */
 333 _PUBLIC_ struct nbt_name_socket *nbt_name_socket_init(TALLOC_CTX *mem_ctx,
 334                                              struct tevent_context *event_ctx)
 335 {
 336         struct nbt_name_socket *nbtsock;
 337         NTSTATUS status;
 338
 339         nbtsock = talloc(mem_ctx, struct nbt_name_socket);
 340         if (nbtsock == NULL) goto failed;
 341
 342         nbtsock->event_ctx = event_ctx;
 343         if (nbtsock->event_ctx == NULL) goto failed;
 344
 345         status = socket_create("ip", SOCKET_TYPE_DGRAM, &nbtsock->sock, 0);
 346         if (!NT_STATUS_IS_OK(status)) goto failed;
 347
 348         socket_set_option(nbtsock->sock, "SO_BROADCAST", "1");
 349
 350         talloc_steal(nbtsock, nbtsock->sock);
 351
 352         nbtsock->idr = idr_init(nbtsock);
 353         if (nbtsock->idr == NULL) goto failed;
 354
 355         nbtsock->send_queue = NULL;
 356         nbtsock->num_pending = 0;
 357         nbtsock->incoming.handler = NULL;
 358         nbtsock->unexpected.handler = NULL;
 359
 360         nbtsock->fde = tevent_add_fd(nbtsock->event_ctx, nbtsock,
 361                                      socket_get_fd(nbtsock->sock), 0,
 362                                      nbt_name_socket_handler, nbtsock);
 363
 364         return nbtsock;
 365
 366 failed:
 367         talloc_free(nbtsock);
 368         return NULL;
 369 }
 370
 371 /*
 372   send off a nbt name request
 373 */
 374 struct nbt_name_request *nbt_name_request_send(struct nbt_name_socket *nbtsock,
 375                                                struct socket_address *dest,
 376                                                struct nbt_name_packet *request,
 377                                                int timeout, int retries,
 378                                                bool allow_multiple_replies)
 379 {
 380         struct nbt_name_request *req;
 381         int id;
 382         enum ndr_err_code ndr_err;
 383
 384         req = talloc_zero(nbtsock, struct nbt_name_request);
 385         if (req == NULL) goto failed;
 386
 387         req->nbtsock                = nbtsock;
 388         req->allow_multiple_replies = allow_multiple_replies;
 389         req->state                  = NBT_REQUEST_SEND;
 390         req->is_reply               = false;
 391         req->timeout                = timeout;
 392         req->num_retries            = retries;
 393         req->dest                   = dest;
 394         if (talloc_reference(req, dest) == NULL) goto failed;
 395
 396         /* we select a random transaction id unless the user supplied one */
 397         if (request->name_trn_id == 0) {
 398                 id = idr_get_new_random(req->nbtsock->idr, req, UINT16_MAX);
 399         } else {
 400                 if (idr_find(req->nbtsock->idr, request->name_trn_id)) goto failed;
 401                 id = idr_get_new_above(req->nbtsock->idr, req, request->name_trn_id,
 402                                        UINT16_MAX);
 403         }
 404         if (id == -1) goto failed;
 405
 406         request->name_trn_id = id;
 407         req->name_trn_id     = id;
 408
 409         req->te = tevent_add_timer(nbtsock->event_ctx, req,
 410                                    timeval_current_ofs(req->timeout, 0),
 411                                    nbt_name_socket_timeout, req);
 412
 413         talloc_set_destructor(req, nbt_name_request_destructor);
 414
 415         ndr_err = ndr_push_struct_blob(&req->encoded, req,
 416                                        request,
 417                                        (ndr_push_flags_fn_t)ndr_push_nbt_name_packet);
 418         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) goto failed;
 419
 420         DLIST_ADD_END(nbtsock->send_queue, req);
 421
 422         if (DEBUGLVL(10)) {
 423                 DEBUG(10,("Queueing nbt packet to %s:%d\n",
 424                           req->dest->addr, req->dest->port));
 425                 NDR_PRINT_DEBUG(nbt_name_packet, request);
 426         }
 427
 428         TEVENT_FD_WRITEABLE(nbtsock->fde);
 429
 430         return req;
 431
 432 failed:
 433         talloc_free(req);
 434         return NULL;
 435 }
 436
 437
 438 /*
 439   send off a nbt name reply
 440 */
 441 _PUBLIC_ NTSTATUS nbt_name_reply_send(struct nbt_name_socket *nbtsock,
 442                              struct socket_address *dest,
 443                              struct nbt_name_packet *request)
 444 {
 445         struct nbt_name_request *req;
 446         enum ndr_err_code ndr_err;
 447
 448         req = talloc_zero(nbtsock, struct nbt_name_request);
 449         NT_STATUS_HAVE_NO_MEMORY(req);
 450
 451         req->nbtsock   = nbtsock;
 452         req->dest = dest;
 453         if (talloc_reference(req, dest) == NULL) goto failed;
 454         req->state     = NBT_REQUEST_SEND;
 455         req->is_reply = true;
 456
 457         talloc_set_destructor(req, nbt_name_request_destructor);
 458
 459         if (DEBUGLVL(10)) {
 460                 NDR_PRINT_DEBUG(nbt_name_packet, request);
 461         }
 462
 463         ndr_err = ndr_push_struct_blob(&req->encoded, req,
 464                                        request,
 465                                        (ndr_push_flags_fn_t)ndr_push_nbt_name_packet);
 466         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 467                 talloc_free(req);
 468                 return ndr_map_error2ntstatus(ndr_err);
 469         }
 470
 471         DLIST_ADD_END(nbtsock->send_queue, req);
 472
 473         TEVENT_FD_WRITEABLE(nbtsock->fde);
 474
 475         return NT_STATUS_OK;
 476
 477 failed:
 478         talloc_free(req);
 479         return NT_STATUS_NO_MEMORY;
 480 }
 481
 482 /*
 483   wait for a nbt request to complete
 484 */
 485 NTSTATUS nbt_name_request_recv(struct nbt_name_request *req)
 486 {
 487         if (!req) return NT_STATUS_NO_MEMORY;
 488
 489         while (req->state < NBT_REQUEST_DONE) {
 490                 if (tevent_loop_once(req->nbtsock->event_ctx) != 0) {
 491                         req->state = NBT_REQUEST_ERROR;
 492                         req->status = NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 493                         break;
 494                 }
 495         }
 496         return req->status;
 497 }
 498
 499
 500 /*
 501   setup a handler for incoming requests
 502 */
 503 _PUBLIC_ NTSTATUS nbt_set_incoming_handler(struct nbt_name_socket *nbtsock,
 504                                   void (*handler)(struct nbt_name_socket *, struct nbt_name_packet *,
 505                                                   struct socket_address *),
 506                                   void *private_data)
 507 {
 508         nbtsock->incoming.handler = handler;
 509         nbtsock->incoming.private_data = private_data;
 510         TEVENT_FD_READABLE(nbtsock->fde);
 511         return NT_STATUS_OK;
 512 }
 513
 514 /*
 515   setup a handler for unexpected requests
 516 */
 517 NTSTATUS nbt_set_unexpected_handler(struct nbt_name_socket *nbtsock,
 518                                     void (*handler)(struct nbt_name_socket *, struct nbt_name_packet *,
 519                                                     struct socket_address *),
 520                                     void *private_data)
 521 {
 522         nbtsock->unexpected.handler = handler;
 523         nbtsock->unexpected.private_data = private_data;
 524         TEVENT_FD_READABLE(nbtsock->fde);
 525         return NT_STATUS_OK;
 526 }
 527
 528 /*
 529   turn a NBT rcode into a NTSTATUS
 530 */
 531 _PUBLIC_ NTSTATUS nbt_rcode_to_ntstatus(uint8_t rcode)
 532 {
 533         int i;
 534         struct {
 535                 enum nbt_rcode rcode;
 536                 NTSTATUS status;
 537         } map[] = {
 538                 { NBT_RCODE_FMT, NT_STATUS_INVALID_PARAMETER },
 539                 { NBT_RCODE_SVR, NT_STATUS_SERVER_DISABLED },
 540                 { NBT_RCODE_NAM, NT_STATUS_OBJECT_NAME_NOT_FOUND },
 541                 { NBT_RCODE_IMP, NT_STATUS_NOT_SUPPORTED },
 542                 { NBT_RCODE_RFS, NT_STATUS_ACCESS_DENIED },
 543                 { NBT_RCODE_ACT, NT_STATUS_ADDRESS_ALREADY_EXISTS },
 544                 { NBT_RCODE_CFT, NT_STATUS_CONFLICTING_ADDRESSES }
 545         };
 546         for (i=0;i<ARRAY_SIZE(map);i++) {
 547                 if (map[i].rcode == rcode) {
 548                         return map[i].status;
 549                 }
 550         }
 551         return NT_STATUS_UNSUCCESSFUL;
 552 }