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                 EVENT_FD_NOT_WRITEABLE(req->nbtsock->fde);
  54         }
  55         if (req->nbtsock->num_pending == 0 &&
  56             req->nbtsock->incoming.handler == NULL) {
  57                 EVENT_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                         EVENT_FD_READABLE(nbtsock->fde);
  91                         nbtsock->num_pending++;
  92                 }
  93         }
  94
  95         EVENT_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)
 119 {
 120         struct nbt_name_request *req = talloc_get_type(private,
 121                                                        struct nbt_name_request);
 122
 123         if (req->num_retries != 0) {
 124                 req->num_retries--;
 125                 req->te = event_add_timed(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                                       struct nbt_name_request *);
 132                 }
 133                 EVENT_FD_WRITEABLE(req->nbtsock->fde);
 134                 return;
 135         }
 136
 137         nbt_name_request_destructor(req);
 138         if (req->num_replies == 0) {
 139                 req->state = NBT_REQUEST_TIMEOUT;
 140                 req->status = NT_STATUS_IO_TIMEOUT;
 141         } else {
 142                 req->state = NBT_REQUEST_DONE;
 143                 req->status = NT_STATUS_OK;
 144         }
 145         if (req->async.fn) {
 146                 req->async.fn(req);
 147         } else if (req->is_reply) {
 148                 talloc_free(req);
 149         }
 150 }
 151
 152
 153
 154 /**
 155   handle recv events on a nbt name socket
 156 */
 157 static void nbt_name_socket_recv(struct nbt_name_socket *nbtsock)
 158 {
 159         TALLOC_CTX *tmp_ctx = talloc_new(nbtsock);
 160         NTSTATUS status;
 161         enum ndr_err_code ndr_err;
 162         struct socket_address *src;
 163         DATA_BLOB blob;
 164         size_t nread, dsize;
 165         struct nbt_name_packet *packet;
 166         struct nbt_name_request *req;
 167
 168         status = socket_pending(nbtsock->sock, &dsize);
 169         if (!NT_STATUS_IS_OK(status)) {
 170                 talloc_free(tmp_ctx);
 171                 return;
 172         }
 173
 174         blob = data_blob_talloc(tmp_ctx, NULL, dsize);
 175         if (blob.data == NULL) {
 176                 talloc_free(tmp_ctx);
 177                 return;
 178         }
 179
 180         status = socket_recvfrom(nbtsock->sock, blob.data, blob.length, &nread,
 181                                  tmp_ctx, &src);
 182         if (!NT_STATUS_IS_OK(status)) {
 183                 talloc_free(tmp_ctx);
 184                 return;
 185         }
 186
 187         packet = talloc(tmp_ctx, struct nbt_name_packet);
 188         if (packet == NULL) {
 189                 talloc_free(tmp_ctx);
 190                 return;
 191         }
 192
 193         /* parse the request */
 194         ndr_err = ndr_pull_struct_blob(&blob, packet, nbtsock->iconv_convenience, packet,
 195                                        (ndr_pull_flags_fn_t)ndr_pull_nbt_name_packet);
 196         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 197                 status = ndr_map_error2ntstatus(ndr_err);
 198                 DEBUG(2,("Failed to parse incoming NBT name packet - %s\n",
 199                          nt_errstr(status)));
 200                 talloc_free(tmp_ctx);
 201                 return;
 202         }
 203
 204         if (DEBUGLVL(10)) {
 205                 DEBUG(10,("Received nbt packet of length %d from %s:%d\n",
 206                           (int)blob.length, src->addr, src->port));
 207                 NDR_PRINT_DEBUG(nbt_name_packet, packet);
 208         }
 209
 210         /* if its not a reply then pass it off to the incoming request
 211            handler, if any */
 212         if (!(packet->operation & NBT_FLAG_REPLY)) {
 213                 if (nbtsock->incoming.handler) {
 214                         nbtsock->incoming.handler(nbtsock, packet, src);
 215                 }
 216                 talloc_free(tmp_ctx);
 217                 return;
 218         }
 219
 220         /* find the matching request */
 221         req = (struct nbt_name_request *)idr_find(nbtsock->idr,
 222                                                   packet->name_trn_id);
 223         if (req == NULL) {
 224                 if (nbtsock->unexpected.handler) {
 225                         nbtsock->unexpected.handler(nbtsock, packet, src);
 226                 } else {
 227                         DEBUG(10,("Failed to match request for incoming name packet id 0x%04x on %p\n",
 228                                  packet->name_trn_id, nbtsock));
 229                 }
 230                 talloc_free(tmp_ctx);
 231                 return;
 232         }
 233
 234         /* if this is a WACK response, this we need to go back to waiting,
 235            but perhaps increase the timeout */
 236         if ((packet->operation & NBT_OPCODE) == NBT_OPCODE_WACK) {
 237                 uint32_t ttl;
 238                 if (req->received_wack || packet->ancount < 1) {
 239                         nbt_name_request_destructor(req);
 240                         req->status = NT_STATUS_INVALID_NETWORK_RESPONSE;
 241                         req->state  = NBT_REQUEST_ERROR;
 242                         goto done;
 243                 }
 244                 talloc_free(req->te);
 245                 /* we know we won't need any more retries - the server
 246                    has received our request */
 247                 req->num_retries   = 0;
 248                 req->received_wack = true;
 249                 /*
 250                  * there is a timeout in the packet,
 251                  * it is 5 + 4 * num_old_addresses
 252                  *
 253                  * although w2k3 screws it up
 254                  * and uses num_old_addresses = 0
 255                  *
 256                  * so we better fallback to the maximum
 257                  * of num_old_addresses = 25 if we got
 258                  * a timeout of less than 9s (5 + 4*1)
 259                  * or more than 105s (5 + 4*25).
 260                  */
 261                 ttl = packet->answers[0].ttl;
 262                 if ((ttl < (5 + 4*1)) || (ttl > (5 + 4*25))) {
 263                         ttl = 5 + 4*25;
 264                 }
 265                 req->timeout = ttl;
 266                 req->te = event_add_timed(req->nbtsock->event_ctx, req,
 267                                           timeval_current_ofs(req->timeout, 0),
 268                                           nbt_name_socket_timeout, req);
 269                 talloc_free(tmp_ctx);
 270                 return;
 271         }
 272
 273
 274         req->replies = talloc_realloc(req, req->replies, struct nbt_name_reply, req->num_replies+1);
 275         if (req->replies == NULL) {
 276                 nbt_name_request_destructor(req);
 277                 req->state  = NBT_REQUEST_ERROR;
 278                 req->status = NT_STATUS_NO_MEMORY;
 279                 goto done;
 280         }
 281
 282         talloc_steal(req, src);
 283         req->replies[req->num_replies].dest   = src;
 284         talloc_steal(req, packet);
 285         req->replies[req->num_replies].packet = packet;
 286         req->num_replies++;
 287
 288         /* if we don't want multiple replies then we are done */
 289         if (req->allow_multiple_replies &&
 290             req->num_replies < NBT_MAX_REPLIES) {
 291                 talloc_free(tmp_ctx);
 292                 return;
 293         }
 294
 295         nbt_name_request_destructor(req);
 296         req->state  = NBT_REQUEST_DONE;
 297         req->status = NT_STATUS_OK;
 298
 299 done:
 300         talloc_free(tmp_ctx);
 301         if (req->async.fn) {
 302                 req->async.fn(req);
 303         }
 304 }
 305
 306 /*
 307   handle fd events on a nbt_name_socket
 308 */
 309 static void nbt_name_socket_handler(struct tevent_context *ev, struct tevent_fd *fde,
 310                                     uint16_t flags, void *private)
 311 {
 312         struct nbt_name_socket *nbtsock = talloc_get_type(private,
 313                                                           struct nbt_name_socket);
 314         if (flags & EVENT_FD_WRITE) {
 315                 nbt_name_socket_send(nbtsock);
 316         }
 317         if (flags & EVENT_FD_READ) {
 318                 nbt_name_socket_recv(nbtsock);
 319         }
 320 }
 321
 322
 323 /*
 324   initialise a nbt_name_socket. The event_ctx is optional, if provided
 325   then operations will use that event context
 326 */
 327 _PUBLIC_ struct nbt_name_socket *nbt_name_socket_init(TALLOC_CTX *mem_ctx,
 328                                              struct tevent_context *event_ctx,
 329                                              struct smb_iconv_convenience *iconv_convenience)
 330 {
 331         struct nbt_name_socket *nbtsock;
 332         NTSTATUS status;
 333
 334         nbtsock = talloc(mem_ctx, struct nbt_name_socket);
 335         if (nbtsock == NULL) goto failed;
 336
 337         nbtsock->event_ctx = talloc_reference(nbtsock, event_ctx);
 338         if (nbtsock->event_ctx == NULL) goto failed;
 339
 340         status = socket_create("ip", SOCKET_TYPE_DGRAM, &nbtsock->sock, 0);
 341         if (!NT_STATUS_IS_OK(status)) goto failed;
 342
 343         socket_set_option(nbtsock->sock, "SO_BROADCAST", "1");
 344
 345         talloc_steal(nbtsock, nbtsock->sock);
 346
 347         nbtsock->idr = idr_init(nbtsock);
 348         if (nbtsock->idr == NULL) goto failed;
 349
 350         nbtsock->send_queue = NULL;
 351         nbtsock->num_pending = 0;
 352         nbtsock->incoming.handler = NULL;
 353         nbtsock->unexpected.handler = NULL;
 354         nbtsock->iconv_convenience = iconv_convenience;
 355
 356         nbtsock->fde = event_add_fd(nbtsock->event_ctx, nbtsock,
 357                                     socket_get_fd(nbtsock->sock), 0,
 358                                     nbt_name_socket_handler, nbtsock);
 359
 360         return nbtsock;
 361
 362 failed:
 363         talloc_free(nbtsock);
 364         return NULL;
 365 }
 366
 367 /*
 368   send off a nbt name request
 369 */
 370 struct nbt_name_request *nbt_name_request_send(struct nbt_name_socket *nbtsock,
 371                                                struct socket_address *dest,
 372                                                struct nbt_name_packet *request,
 373                                                int timeout, int retries,
 374                                                bool allow_multiple_replies)
 375 {
 376         struct nbt_name_request *req;
 377         int id;
 378         enum ndr_err_code ndr_err;
 379
 380         req = talloc_zero(nbtsock, struct nbt_name_request);
 381         if (req == NULL) goto failed;
 382
 383         req->nbtsock                = nbtsock;
 384         req->allow_multiple_replies = allow_multiple_replies;
 385         req->state                  = NBT_REQUEST_SEND;
 386         req->is_reply               = false;
 387         req->timeout                = timeout;
 388         req->num_retries            = retries;
 389         req->dest                   = dest;
 390         if (talloc_reference(req, dest) == NULL) goto failed;
 391
 392         /* we select a random transaction id unless the user supplied one */
 393         if (request->name_trn_id == 0) {
 394                 id = idr_get_new_random(req->nbtsock->idr, req, UINT16_MAX);
 395         } else {
 396                 if (idr_find(req->nbtsock->idr, request->name_trn_id)) goto failed;
 397                 id = idr_get_new_above(req->nbtsock->idr, req, request->name_trn_id,
 398                                        UINT16_MAX);
 399         }
 400         if (id == -1) goto failed;
 401
 402         request->name_trn_id = id;
 403         req->name_trn_id     = id;
 404
 405         req->te = event_add_timed(nbtsock->event_ctx, req,
 406                                   timeval_current_ofs(req->timeout, 0),
 407                                   nbt_name_socket_timeout, req);
 408
 409         talloc_set_destructor(req, nbt_name_request_destructor);
 410
 411         ndr_err = ndr_push_struct_blob(&req->encoded, req,
 412                                        req->nbtsock->iconv_convenience,
 413                                        request,
 414                                        (ndr_push_flags_fn_t)ndr_push_nbt_name_packet);
 415         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) goto failed;
 416
 417         DLIST_ADD_END(nbtsock->send_queue, req, struct nbt_name_request *);
 418
 419         if (DEBUGLVL(10)) {
 420                 DEBUG(10,("Queueing nbt packet to %s:%d\n",
 421                           req->dest->addr, req->dest->port));
 422                 NDR_PRINT_DEBUG(nbt_name_packet, request);
 423         }
 424
 425         EVENT_FD_WRITEABLE(nbtsock->fde);
 426
 427         return req;
 428
 429 failed:
 430         talloc_free(req);
 431         return NULL;
 432 }
 433
 434
 435 /*
 436   send off a nbt name reply
 437 */
 438 _PUBLIC_ NTSTATUS nbt_name_reply_send(struct nbt_name_socket *nbtsock,
 439                              struct socket_address *dest,
 440                              struct nbt_name_packet *request)
 441 {
 442         struct nbt_name_request *req;
 443         enum ndr_err_code ndr_err;
 444
 445         req = talloc_zero(nbtsock, struct nbt_name_request);
 446         NT_STATUS_HAVE_NO_MEMORY(req);
 447
 448         req->nbtsock   = nbtsock;
 449         req->dest = dest;
 450         if (talloc_reference(req, dest) == NULL) goto failed;
 451         req->state     = NBT_REQUEST_SEND;
 452         req->is_reply = true;
 453
 454         talloc_set_destructor(req, nbt_name_request_destructor);
 455
 456         if (DEBUGLVL(10)) {
 457                 NDR_PRINT_DEBUG(nbt_name_packet, request);
 458         }
 459
 460         ndr_err = ndr_push_struct_blob(&req->encoded, req,
 461                                        req->nbtsock->iconv_convenience,
 462                                        request,
 463                                        (ndr_push_flags_fn_t)ndr_push_nbt_name_packet);
 464         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 465                 talloc_free(req);
 466                 return ndr_map_error2ntstatus(ndr_err);
 467         }
 468
 469         DLIST_ADD_END(nbtsock->send_queue, req, struct nbt_name_request *);
 470
 471         EVENT_FD_WRITEABLE(nbtsock->fde);
 472
 473         return NT_STATUS_OK;
 474
 475 failed:
 476         talloc_free(req);
 477         return NT_STATUS_NO_MEMORY;
 478 }
 479
 480 /*
 481   wait for a nbt request to complete
 482 */
 483 NTSTATUS nbt_name_request_recv(struct nbt_name_request *req)
 484 {
 485         if (!req) return NT_STATUS_NO_MEMORY;
 486
 487         while (req->state < NBT_REQUEST_DONE) {
 488                 if (event_loop_once(req->nbtsock->event_ctx) != 0) {
 489                         req->state = NBT_REQUEST_ERROR;
 490                         req->status = NT_STATUS_UNEXPECTED_NETWORK_ERROR;
 491                         break;
 492                 }
 493         }
 494         return req->status;
 495 }
 496
 497
 498 /*
 499   setup a handler for incoming requests
 500 */
 501 _PUBLIC_ NTSTATUS nbt_set_incoming_handler(struct nbt_name_socket *nbtsock,
 502                                   void (*handler)(struct nbt_name_socket *, struct nbt_name_packet *,
 503                                                   struct socket_address *),
 504                                   void *private)
 505 {
 506         nbtsock->incoming.handler = handler;
 507         nbtsock->incoming.private_data = private;
 508         EVENT_FD_READABLE(nbtsock->fde);
 509         return NT_STATUS_OK;
 510 }
 511
 512 /*
 513   setup a handler for unexpected requests
 514 */
 515 NTSTATUS nbt_set_unexpected_handler(struct nbt_name_socket *nbtsock,
 516                                     void (*handler)(struct nbt_name_socket *, struct nbt_name_packet *,
 517                                                     struct socket_address *),
 518                                     void *private)
 519 {
 520         nbtsock->unexpected.handler = handler;
 521         nbtsock->unexpected.private_data = private;
 522         EVENT_FD_READABLE(nbtsock->fde);
 523         return NT_STATUS_OK;
 524 }
 525
 526 /*
 527   turn a NBT rcode into a NTSTATUS
 528 */
 529 _PUBLIC_ NTSTATUS nbt_rcode_to_ntstatus(uint8_t rcode)
 530 {
 531         int i;
 532         struct {
 533                 enum nbt_rcode rcode;
 534                 NTSTATUS status;
 535         } map[] = {
 536                 { NBT_RCODE_FMT, NT_STATUS_INVALID_PARAMETER },
 537                 { NBT_RCODE_SVR, NT_STATUS_SERVER_DISABLED },
 538                 { NBT_RCODE_NAM, NT_STATUS_OBJECT_NAME_NOT_FOUND },
 539                 { NBT_RCODE_IMP, NT_STATUS_NOT_SUPPORTED },
 540                 { NBT_RCODE_RFS, NT_STATUS_ACCESS_DENIED },
 541                 { NBT_RCODE_ACT, NT_STATUS_ADDRESS_ALREADY_EXISTS },
 542                 { NBT_RCODE_CFT, NT_STATUS_CONFLICTING_ADDRESSES }
 543         };
 544         for (i=0;i<ARRAY_SIZE(map);i++) {
 545                 if (map[i].rcode == rcode) {
 546                         return map[i].status;
 547                 }
 548         }
 549         return NT_STATUS_UNSUCCESSFUL;
 550 }