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 #include "lib/util/idtree_random.h"
  31
  32 #define NBT_MAX_REPLIES 1000
  33
  34 /*
  35   destroy a pending request
  36 */
  37 static int nbt_name_request_destructor(struct nbt_name_request *req)
  38 {
  39         if (req->state == NBT_REQUEST_SEND) {
  40                 DLIST_REMOVE(req->nbtsock->send_queue, req);
  41         }
  42         if (req->state == NBT_REQUEST_WAIT) {
  43                 req->nbtsock->num_pending--;
  44         }
  45         if (req->name_trn_id != 0 && !req->is_reply) {
  46                 idr_remove(req->nbtsock->idr, req->name_trn_id);
  47                 req->name_trn_id = 0;
  48         }
  49         TALLOC_FREE(req->te);
  50         if (req->nbtsock->send_queue == NULL) {
  51                 TEVENT_FD_NOT_WRITEABLE(req->nbtsock->fde);
  52         }
  53         if (req->nbtsock->num_pending == 0 &&
  54             req->nbtsock->incoming.handler == NULL) {
  55                 TEVENT_FD_NOT_READABLE(req->nbtsock->fde);
  56         }
  57         return 0;
  58 }
  59
  60
  61 /*
  62   handle send events on a nbt name socket
  63 */
  64 static void nbt_name_socket_send(struct nbt_name_socket *nbtsock)
  65 {
  66         struct nbt_name_request *req;
  67         TALLOC_CTX *tmp_ctx = talloc_new(nbtsock);
  68         NTSTATUS status;
  69
  70         while ((req = nbtsock->send_queue)) {
  71                 size_t len;
  72
  73                 len = req->encoded.length;
  74                 status = socket_sendto(nbtsock->sock, &req->encoded, &len,
  75                                        req->dest);
  76                 if (NT_STATUS_IS_ERR(status)) goto failed;
  77
  78                 if (!NT_STATUS_IS_OK(status)) {
  79                         talloc_free(tmp_ctx);
  80                         return;
  81                 }
  82
  83                 DLIST_REMOVE(nbtsock->send_queue, req);
  84                 req->state = NBT_REQUEST_WAIT;
  85                 if (req->is_reply) {
  86                         talloc_free(req);
  87                 } else {
  88                         TEVENT_FD_READABLE(nbtsock->fde);
  89                         nbtsock->num_pending++;
  90                 }
  91         }
  92
  93         TEVENT_FD_NOT_WRITEABLE(nbtsock->fde);
  94         talloc_free(tmp_ctx);
  95         return;
  96
  97 failed:
  98         DLIST_REMOVE(nbtsock->send_queue, req);
  99         nbt_name_request_destructor(req);
 100         req->status = status;
 101         req->state = NBT_REQUEST_ERROR;
 102         talloc_free(tmp_ctx);
 103         if (req->async.fn) {
 104                 req->async.fn(req);
 105         } else if (req->is_reply) {
 106                 talloc_free(req);
 107         }
 108         return;
 109 }
 110
 111
 112 /*
 113   handle a request timeout
 114 */
 115 static void nbt_name_socket_timeout(struct tevent_context *ev, struct tevent_timer *te,
 116                                     struct timeval t, void *private_data)
 117 {
 118         struct nbt_name_request *req = talloc_get_type(private_data,
 119                                                        struct nbt_name_request);
 120
 121         if (req->num_retries != 0) {
 122                 req->num_retries--;
 123                 req->te = tevent_add_timer(req->nbtsock->event_ctx, req,
 124                                            timeval_add(&t, req->timeout, 0),
 125                                            nbt_name_socket_timeout, req);
 126                 if (req->state != NBT_REQUEST_SEND) {
 127                         req->state = NBT_REQUEST_SEND;
 128                         DLIST_ADD_END(req->nbtsock->send_queue, req);
 129                 }
 130                 TEVENT_FD_WRITEABLE(req->nbtsock->fde);
 131                 return;
 132         }
 133
 134         nbt_name_request_destructor(req);
 135         if (req->num_replies == 0) {
 136                 req->state = NBT_REQUEST_TIMEOUT;
 137                 req->status = NT_STATUS_IO_TIMEOUT;
 138         } else {
 139                 req->state = NBT_REQUEST_DONE;
 140                 req->status = NT_STATUS_OK;
 141         }
 142         if (req->async.fn) {
 143                 req->async.fn(req);
 144         } else if (req->is_reply) {
 145                 talloc_free(req);
 146         }
 147 }
 148
 149
 150
 151 /**
 152   handle recv events on a nbt name socket
 153 */
 154 static void nbt_name_socket_recv(struct nbt_name_socket *nbtsock)
 155 {
 156         TALLOC_CTX *tmp_ctx = talloc_new(nbtsock);
 157         NTSTATUS status;
 158         enum ndr_err_code ndr_err;
 159         struct socket_address *src;
 160         DATA_BLOB blob;
 161         size_t nread, dsize;
 162         struct nbt_name_packet *packet;
 163         struct nbt_name_request *req;
 164
 165         status = socket_pending(nbtsock->sock, &dsize);
 166         if (!NT_STATUS_IS_OK(status)) {
 167                 talloc_free(tmp_ctx);
 168                 return;
 169         }
 170
 171         /*
 172          * Given a zero length, data_blob_talloc() returns the
 173          * NULL blob {NULL, 0}.
 174          *
 175          * We only want to error return here on a real out of memory condition
 176          * (i.e. dsize != 0, so the UDP packet has data, but the return of the
 177          * allocation failed, so blob.data==NULL).
 178          *
 179          * Given an actual zero length UDP packet having blob.data == NULL
 180          * isn't an out of memory error condition, that's the defined semantics
 181          * of data_blob_talloc() when asked for zero bytes.
 182          *
 183          * We still need to continue to do the zero-length socket_recvfrom()
 184          * read in order to clear the "read pending" condition on the socket.
 185          */
 186         blob = data_blob_talloc(tmp_ctx, NULL, dsize);
 187         if (blob.data == NULL && dsize != 0) {
 188                 talloc_free(tmp_ctx);
 189                 return;
 190         }
 191
 192         status = socket_recvfrom(nbtsock->sock, blob.data, blob.length, &nread,
 193                                  tmp_ctx, &src);
 194         if (!NT_STATUS_IS_OK(status)) {
 195                 talloc_free(tmp_ctx);
 196                 return;
 197         }
 198
 199         packet = talloc(tmp_ctx, struct nbt_name_packet);
 200         if (packet == NULL) {
 201                 talloc_free(tmp_ctx);
 202                 return;
 203         }
 204
 205         /* parse the request */
 206         ndr_err = ndr_pull_struct_blob(&blob, packet, packet,
 207                                        (ndr_pull_flags_fn_t)ndr_pull_nbt_name_packet);
 208         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 209                 status = ndr_map_error2ntstatus(ndr_err);
 210                 DEBUG(2,("Failed to parse incoming NBT name packet - %s\n",
 211                          nt_errstr(status)));
 212                 talloc_free(tmp_ctx);
 213                 return;
 214         }
 215
 216         if (DEBUGLVL(10)) {
 217                 DEBUG(10,("Received nbt packet of length %d from %s:%d\n",
 218                           (int)blob.length, src->addr, src->port));
 219                 NDR_PRINT_DEBUG(nbt_name_packet, packet);
 220         }
 221
 222         /* if its not a reply then pass it off to the incoming request
 223            handler, if any */
 224         if (!(packet->operation & NBT_FLAG_REPLY)) {
 225                 if (nbtsock->incoming.handler) {
 226                         nbtsock->incoming.handler(nbtsock, packet, src);
 227                 }
 228                 talloc_free(tmp_ctx);
 229                 return;
 230         }
 231
 232         /* find the matching request */
 233         req = (struct nbt_name_request *)idr_find(nbtsock->idr,
 234                                                   packet->name_trn_id);
 235         if (req == NULL) {
 236                 if (nbtsock->unexpected.handler) {
 237                         nbtsock->unexpected.handler(nbtsock, packet, src);
 238                 } else {
 239                         DEBUG(10,("Failed to match request for incoming name packet id 0x%04x on %p\n",
 240                                  packet->name_trn_id, nbtsock));
 241                 }
 242                 talloc_free(tmp_ctx);
 243                 return;
 244         }
 245
 246         talloc_steal(req, packet);
 247         talloc_steal(req, src);
 248         talloc_free(tmp_ctx);
 249         nbt_name_socket_handle_response_packet(req, packet, src);
 250 }
 251
 252 void nbt_name_socket_handle_response_packet(struct nbt_name_request *req,
 253                                             struct nbt_name_packet *packet,
 254                                             struct socket_address *src)
 255 {
 256         /* if this is a WACK response, this we need to go back to waiting,
 257            but perhaps increase the timeout */
 258         if ((packet->operation & NBT_OPCODE) == NBT_OPCODE_WACK) {
 259                 uint32_t ttl;
 260                 if (req->received_wack || packet->ancount < 1) {
 261                         nbt_name_request_destructor(req);
 262                         req->status = NT_STATUS_INVALID_NETWORK_RESPONSE;
 263                         req->state  = NBT_REQUEST_ERROR;
 264                         goto done;
 265                 }
 266                 talloc_free(req->te);
 267                 /* we know we won't need any more retries - the server
 268                    has received our request */
 269                 req->num_retries   = 0;
 270                 req->received_wack = true;
 271                 /*
 272                  * there is a timeout in the packet,
 273                  * it is 5 + 4 * num_old_addresses
 274                  *
 275                  * although w2k3 screws it up
 276                  * and uses num_old_addresses = 0
 277                  *
 278                  * so we better fallback to the maximum
 279                  * of num_old_addresses = 25 if we got
 280                  * a timeout of less than 9s (5 + 4*1)
 281                  * or more than 105s (5 + 4*25).
 282                  */
 283                 ttl = packet->answers[0].ttl;
 284                 if ((ttl < (5 + 4*1)) || (ttl > (5 + 4*25))) {
 285                         ttl = 5 + 4*25;
 286                 }
 287                 req->timeout = ttl;
 288                 req->te = tevent_add_timer(req->nbtsock->event_ctx, req,
 289                                            timeval_current_ofs(req->timeout, 0),
 290                                            nbt_name_socket_timeout, req);
 291                 return;
 292         }
 293
 294
 295         req->replies = talloc_realloc(req, req->replies, struct nbt_name_reply, req->num_replies+1);
 296         if (req->replies == NULL) {
 297                 nbt_name_request_destructor(req);
 298                 req->state  = NBT_REQUEST_ERROR;
 299                 req->status = NT_STATUS_NO_MEMORY;
 300                 goto done;
 301         }
 302
 303         talloc_steal(req, src);
 304         req->replies[req->num_replies].dest   = src;
 305         talloc_steal(req, packet);
 306         req->replies[req->num_replies].packet = packet;
 307         req->num_replies++;
 308
 309         /* if we don't want multiple replies then we are done */
 310         if (req->allow_multiple_replies &&
 311             req->num_replies < NBT_MAX_REPLIES) {
 312                 return;
 313         }
 314
 315         nbt_name_request_destructor(req);
 316         req->state  = NBT_REQUEST_DONE;
 317         req->status = NT_STATUS_OK;
 318
 319 done:
 320         if (req->async.fn) {
 321                 req->async.fn(req);
 322         }
 323 }
 324
 325 /*
 326   handle fd events on a nbt_name_socket
 327 */
 328 static void nbt_name_socket_handler(struct tevent_context *ev, struct tevent_fd *fde,
 329                                     uint16_t flags, void *private_data)
 330 {
 331         struct nbt_name_socket *nbtsock = talloc_get_type(private_data,
 332                                                           struct nbt_name_socket);
 333         if (flags & TEVENT_FD_WRITE) {
 334                 nbt_name_socket_send(nbtsock);
 335         }
 336         if (flags & TEVENT_FD_READ) {
 337                 nbt_name_socket_recv(nbtsock);
 338         }
 339 }
 340
 341
 342 /*
 343   initialise a nbt_name_socket. The event_ctx is optional, if provided
 344   then operations will use that event context
 345 */
 346 _PUBLIC_ struct nbt_name_socket *nbt_name_socket_init(TALLOC_CTX *mem_ctx,
 347                                              struct tevent_context *event_ctx)
 348 {
 349         struct nbt_name_socket *nbtsock;
 350         NTSTATUS status;
 351
 352         nbtsock = talloc(mem_ctx, struct nbt_name_socket);
 353         if (nbtsock == NULL) goto failed;
 354
 355         nbtsock->event_ctx = event_ctx;
 356         if (nbtsock->event_ctx == NULL) goto failed;
 357
 358         status = socket_create(nbtsock, "ip", SOCKET_TYPE_DGRAM,
 359                                &nbtsock->sock, 0);
 360         if (!NT_STATUS_IS_OK(status)) goto failed;
 361
 362         socket_set_option(nbtsock->sock, "SO_BROADCAST", "1");
 363
 364         nbtsock->idr = idr_init(nbtsock);
 365         if (nbtsock->idr == NULL) goto failed;
 366
 367         nbtsock->send_queue = NULL;
 368         nbtsock->num_pending = 0;
 369         nbtsock->incoming.handler = NULL;
 370         nbtsock->unexpected.handler = NULL;
 371
 372         nbtsock->fde = tevent_add_fd(nbtsock->event_ctx, nbtsock,
 373                                      socket_get_fd(nbtsock->sock), 0,
 374                                      nbt_name_socket_handler, nbtsock);
 375
 376         return nbtsock;
 377
 378 failed:
 379         talloc_free(nbtsock);
 380         return NULL;
 381 }
 382
 383 /*
 384   send off a nbt name request
 385 */
 386 struct nbt_name_request *nbt_name_request_send(TALLOC_CTX *mem_ctx,
 387                                                struct nbt_name_socket *nbtsock,
 388                                                struct socket_address *dest,
 389                                                struct nbt_name_packet *request,
 390                                                int timeout, int retries,
 391                                                bool allow_multiple_replies)
 392 {
 393         struct nbt_name_request *req;
 394         int id;
 395         enum ndr_err_code ndr_err;
 396
 397         req = talloc_zero(mem_ctx, struct nbt_name_request);
 398         if (req == NULL) goto failed;
 399
 400         req->nbtsock                = nbtsock;
 401         req->allow_multiple_replies = allow_multiple_replies;
 402         req->state                  = NBT_REQUEST_SEND;
 403         req->is_reply               = false;
 404         req->timeout                = timeout;
 405         req->num_retries            = retries;
 406         req->dest                   = socket_address_copy(req, dest);
 407         if (req->dest == NULL) goto failed;
 408
 409         /* we select a random transaction id unless the user supplied one */
 410         if (request->name_trn_id == 0) {
 411                 id = idr_get_new_random(
 412                         req->nbtsock->idr, req, 1, UINT16_MAX);
 413         } else {
 414                 if (idr_find(req->nbtsock->idr, request->name_trn_id)) goto failed;
 415                 id = idr_get_new_above(req->nbtsock->idr, req, request->name_trn_id,
 416                                        UINT16_MAX);
 417         }
 418         if (id == -1) goto failed;
 419
 420         request->name_trn_id = id;
 421         req->name_trn_id     = id;
 422
 423         req->te = tevent_add_timer(nbtsock->event_ctx, req,
 424                                    timeval_current_ofs(req->timeout, 0),
 425                                    nbt_name_socket_timeout, req);
 426
 427         talloc_set_destructor(req, nbt_name_request_destructor);
 428
 429         ndr_err = ndr_push_struct_blob(&req->encoded, req,
 430                                        request,
 431                                        (ndr_push_flags_fn_t)ndr_push_nbt_name_packet);
 432         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) goto failed;
 433
 434         DLIST_ADD_END(nbtsock->send_queue, req);
 435
 436         if (DEBUGLVL(10)) {
 437                 DEBUG(10,("Queueing nbt packet to %s:%d\n",
 438                           req->dest->addr, req->dest->port));
 439                 NDR_PRINT_DEBUG(nbt_name_packet, request);
 440         }
 441
 442         TEVENT_FD_WRITEABLE(nbtsock->fde);
 443
 444         return req;
 445
 446 failed:
 447         talloc_free(req);
 448         return NULL;
 449 }
 450
 451
 452 /*
 453   send off a nbt name reply
 454 */
 455 _PUBLIC_ NTSTATUS nbt_name_reply_send(struct nbt_name_socket *nbtsock,
 456                              struct socket_address *dest,
 457                              struct nbt_name_packet *request)
 458 {
 459         struct nbt_name_request *req;
 460         enum ndr_err_code ndr_err;
 461
 462         req = talloc_zero(nbtsock, struct nbt_name_request);
 463         NT_STATUS_HAVE_NO_MEMORY(req);
 464
 465         req->nbtsock   = nbtsock;
 466         req->dest = socket_address_copy(req, dest);
 467         if (req->dest == NULL) goto failed;
 468         req->state     = NBT_REQUEST_SEND;
 469         req->is_reply = true;
 470
 471         talloc_set_destructor(req, nbt_name_request_destructor);
 472
 473         if (DEBUGLVL(10)) {
 474                 NDR_PRINT_DEBUG(nbt_name_packet, request);
 475         }
 476
 477         ndr_err = ndr_push_struct_blob(&req->encoded, req,
 478                                        request,
 479                                        (ndr_push_flags_fn_t)ndr_push_nbt_name_packet);
 480         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 481                 talloc_free(req);
 482                 return ndr_map_error2ntstatus(ndr_err);
 483         }
 484
 485         DLIST_ADD_END(nbtsock->send_queue, req);
 486
 487         TEVENT_FD_WRITEABLE(nbtsock->fde);
 488
 489         return NT_STATUS_OK;
 490
 491 failed:
 492         talloc_free(req);
 493         return NT_STATUS_NO_MEMORY;
 494 }
 495
 496 /*
 497   wait for a nbt request to complete
 498 */
 499 NTSTATUS nbt_name_request_recv(struct nbt_name_request *req)
 500 {
 501         if (!req) return NT_STATUS_NO_MEMORY;
 502
 503         while (req->state < NBT_REQUEST_DONE) {
 504                 if (tevent_loop_once(req->nbtsock->event_ctx) != 0) {
 505                         req->state = NBT_REQUEST_ERROR;
 506                         req->status = NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 507                         break;
 508                 }
 509         }
 510         return req->status;
 511 }
 512
 513
 514 /*
 515   setup a handler for incoming requests
 516 */
 517 _PUBLIC_ NTSTATUS nbt_set_incoming_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->incoming.handler = handler;
 523         nbtsock->incoming.private_data = private_data;
 524         TEVENT_FD_READABLE(nbtsock->fde);
 525         return NT_STATUS_OK;
 526 }
 527
 528 /*
 529   setup a handler for unexpected requests
 530 */
 531 NTSTATUS nbt_set_unexpected_handler(struct nbt_name_socket *nbtsock,
 532                                     void (*handler)(struct nbt_name_socket *, struct nbt_name_packet *,
 533                                                     struct socket_address *),
 534                                     void *private_data)
 535 {
 536         nbtsock->unexpected.handler = handler;
 537         nbtsock->unexpected.private_data = private_data;
 538         TEVENT_FD_READABLE(nbtsock->fde);
 539         return NT_STATUS_OK;
 540 }
 541
 542 /*
 543   turn a NBT rcode into a NTSTATUS
 544 */
 545 _PUBLIC_ NTSTATUS nbt_rcode_to_ntstatus(uint8_t rcode)
 546 {
 547         size_t i;
 548         struct {
 549                 enum nbt_rcode rcode;
 550                 NTSTATUS status;
 551         } map[] = {
 552                 { NBT_RCODE_FMT, NT_STATUS_INVALID_PARAMETER },
 553                 { NBT_RCODE_SVR, NT_STATUS_SERVER_DISABLED },
 554                 { NBT_RCODE_NAM, NT_STATUS_OBJECT_NAME_NOT_FOUND },
 555                 { NBT_RCODE_IMP, NT_STATUS_NOT_SUPPORTED },
 556                 { NBT_RCODE_RFS, NT_STATUS_ACCESS_DENIED },
 557                 { NBT_RCODE_ACT, NT_STATUS_ADDRESS_ALREADY_EXISTS },
 558                 { NBT_RCODE_CFT, NT_STATUS_CONFLICTING_ADDRESSES }
 559         };
 560         for (i=0;i<ARRAY_SIZE(map);i++) {
 561                 if (map[i].rcode == rcode) {
 562                         return map[i].status;
 563                 }
 564         }
 565         return NT_STATUS_UNSUCCESSFUL;
 566 }