source3/libsmb/clientgen.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    SMB client generic functions
   4    Copyright (C) Andrew Tridgell 1994-1998
   5    Copyright (C) Jeremy Allison 2007.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 #include "includes.h"
  23
  24 extern int smb_read_error;
  25
  26 /****************************************************************************
  27  Change the timeout (in milliseconds).
  28 ****************************************************************************/
  29
  30 unsigned int cli_set_timeout(struct cli_state *cli, unsigned int timeout)
  31 {
  32         unsigned int old_timeout = cli->timeout;
  33         cli->timeout = timeout;
  34         return old_timeout;
  35 }
  36
  37 /****************************************************************************
  38  Change the port number used to call on.
  39 ****************************************************************************/
  40
  41 int cli_set_port(struct cli_state *cli, int port)
  42 {
  43         cli->port = port;
  44         return port;
  45 }
  46
  47 /****************************************************************************
  48  Read an smb from a fd ignoring all keepalive packets. Note that the buffer
  49  *MUST* be of size BUFFER_SIZE+SAFETY_MARGIN.
  50  The timeout is in milliseconds
  51
  52  This is exactly the same as receive_smb except that it can be set to never return
  53  a session keepalive packet (just as receive_smb used to do).
  54  receive_smb was changed to return keepalives as the oplock processing means this call
  55  should never go into a blocking read.
  56 ****************************************************************************/
  57
  58 static ssize_t client_receive_smb(struct cli_state *cli, BOOL eat_keepalives, size_t maxlen)
  59 {
  60         ssize_t len;
  61         int fd = cli->fd;
  62         char *buffer = cli->inbuf;
  63         unsigned int timeout = cli->timeout;
  64
  65         for(;;) {
  66                 len = receive_smb_raw(fd, buffer, timeout, maxlen);
  67
  68                 if (len < 0) {
  69                         DEBUG(10,("client_receive_smb failed\n"));
  70                         show_msg(buffer);
  71                         return len;
  72                 }
  73
  74                 /* Ignore session keepalive packets. */
  75                 if (eat_keepalives && (CVAL(buffer,0) == SMBkeepalive)) {
  76                         continue;
  77                 }
  78                 break;
  79         }
  80
  81         if (cli_encryption_on(cli)) {
  82                 NTSTATUS status = cli_decrypt_message(cli);
  83                 if (!NT_STATUS_IS_OK(status)) {
  84                         DEBUG(0, ("SMB decryption failed on incoming packet! Error %s\n",
  85                                 nt_errstr(status)));
  86                         cli->smb_rw_error = READ_BAD_DECRYPT;
  87                         close(cli->fd);
  88                         cli->fd = -1;
  89                         return -1;
  90                 }
  91         }
  92         show_msg(buffer);
  93         return len;
  94 }
  95
  96 /****************************************************************************
  97  Recv an smb.
  98 ****************************************************************************/
  99
 100 BOOL cli_receive_smb_internal(struct cli_state *cli, BOOL eat_keepalives)
 101 {
 102         ssize_t len;
 103
 104         /* fd == -1 causes segfaults -- Tom (tom@ninja.nl) */
 105         if (cli->fd == -1)
 106                 return False;
 107
 108  again:
 109         len = client_receive_smb(cli, eat_keepalives, 0);
 110
 111         if (len >= 0 && !eat_keepalives && (CVAL(cli->inbuf,0) == SMBkeepalive)) {
 112                 /* Give back the keepalive. */
 113                 return True;
 114         }
 115
 116         if (len > 0) {
 117                 /* it might be an oplock break request */
 118                 if (!(CVAL(cli->inbuf, smb_flg) & FLAG_REPLY) &&
 119                     CVAL(cli->inbuf,smb_com) == SMBlockingX &&
 120                     SVAL(cli->inbuf,smb_vwv6) == 0 &&
 121                     SVAL(cli->inbuf,smb_vwv7) == 0) {
 122                         if (cli->oplock_handler) {
 123                                 int fnum = SVAL(cli->inbuf,smb_vwv2);
 124                                 unsigned char level = CVAL(cli->inbuf,smb_vwv3+1);
 125                                 if (!cli->oplock_handler(cli, fnum, level)) {
 126                                         return False;
 127                                 }
 128                         }
 129                         /* try to prevent loops */
 130                         SCVAL(cli->inbuf,smb_com,0xFF);
 131                         goto again;
 132                 }
 133         }
 134
 135         /* If the server is not responding, note that now */
 136         if (len < 0) {
 137                 DEBUG(0, ("Receiving SMB: Server stopped responding\n"));
 138                 cli->smb_rw_error = smb_read_error;
 139                 close(cli->fd);
 140                 cli->fd = -1;
 141                 return False;
 142         }
 143
 144         if (!cli_check_sign_mac(cli)) {
 145                 /*
 146                  * If we get a signature failure in sessionsetup, then
 147                  * the server sometimes just reflects the sent signature
 148                  * back to us. Detect this and allow the upper layer to
 149                  * retrieve the correct Windows error message.
 150                  */
 151                 if (CVAL(cli->outbuf,smb_com) == SMBsesssetupX &&
 152                         (smb_len(cli->inbuf) > (smb_ss_field + 8 - 4)) &&
 153                         (SVAL(cli->inbuf,smb_flg2) & FLAGS2_SMB_SECURITY_SIGNATURES) &&
 154                         memcmp(&cli->outbuf[smb_ss_field],&cli->inbuf[smb_ss_field],8) == 0 &&
 155                         cli_is_error(cli)) {
 156
 157                         /*
 158                          * Reflected signature on login error.
 159                          * Set bad sig but don't close fd.
 160                          */
 161                         cli->smb_rw_error = READ_BAD_SIG;
 162                         return True;
 163                 }
 164
 165                 DEBUG(0, ("SMB Signature verification failed on incoming packet!\n"));
 166                 cli->smb_rw_error = READ_BAD_SIG;
 167                 close(cli->fd);
 168                 cli->fd = -1;
 169                 return False;
 170         }
 171
 172         return True;
 173 }
 174
 175 /****************************************************************************
 176  Recv an smb - eat keepalives.
 177 ****************************************************************************/
 178
 179 BOOL cli_receive_smb(struct cli_state *cli)
 180 {
 181         return cli_receive_smb_internal(cli, True);
 182 }
 183
 184 /****************************************************************************
 185  Recv an smb - return keepalives.
 186 ****************************************************************************/
 187
 188 BOOL cli_receive_smb_return_keepalive(struct cli_state *cli)
 189 {
 190         return cli_receive_smb_internal(cli, False);
 191 }
 192
 193 /****************************************************************************
 194  Read the data portion of a readX smb.
 195  The timeout is in milliseconds
 196 ****************************************************************************/
 197
 198 ssize_t cli_receive_smb_data(struct cli_state *cli, char *buffer, size_t len)
 199 {
 200         if (cli->timeout > 0) {
 201                 return read_socket_with_timeout(cli->fd, buffer, len, len, cli->timeout);
 202         } else {
 203                 return read_data(cli->fd, buffer, len);
 204         }
 205 }
 206
 207 /****************************************************************************
 208  Read a smb readX header.
 209  We can only use this if encryption and signing are off.
 210 ****************************************************************************/
 211
 212 BOOL cli_receive_smb_readX_header(struct cli_state *cli)
 213 {
 214         ssize_t len, offset;
 215
 216         if (cli->fd == -1)
 217                 return False;
 218
 219  again:
 220
 221         /* Read up to the size of a readX header reply. */
 222         len = client_receive_smb(cli, True, (smb_size - 4) + 24);
 223
 224         if (len > 0) {
 225                 /* it might be an oplock break request */
 226                 if (!(CVAL(cli->inbuf, smb_flg) & FLAG_REPLY) &&
 227                     CVAL(cli->inbuf,smb_com) == SMBlockingX &&
 228                     SVAL(cli->inbuf,smb_vwv6) == 0 &&
 229                     SVAL(cli->inbuf,smb_vwv7) == 0) {
 230                         ssize_t total_len = smb_len(cli->inbuf);
 231
 232                         if (total_len > CLI_SAMBA_MAX_LARGE_READX_SIZE+SAFETY_MARGIN) {
 233                                 goto read_err;
 234                         }
 235
 236                         /* Read the rest of the data. */
 237                         if ((total_len - len > 0) &&
 238                             !cli_receive_smb_data(cli,cli->inbuf+len,total_len - len)) {
 239                                 goto read_err;
 240                         }
 241
 242                         if (cli->oplock_handler) {
 243                                 int fnum = SVAL(cli->inbuf,smb_vwv2);
 244                                 unsigned char level = CVAL(cli->inbuf,smb_vwv3+1);
 245                                 if (!cli->oplock_handler(cli, fnum, level)) return False;
 246                         }
 247                         /* try to prevent loops */
 248                         SCVAL(cli->inbuf,smb_com,0xFF);
 249                         goto again;
 250                 }
 251         }
 252
 253         /* If it's not the above size it probably was an error packet. */
 254
 255         if ((len == (smb_size - 4) + 24) && !cli_is_error(cli)) {
 256                 /* Check it's a non-chained readX reply. */
 257                 if (!(CVAL(cli->inbuf, smb_flg) & FLAG_REPLY) ||
 258                         (CVAL(cli->inbuf,smb_vwv0) != 0xFF) ||
 259                         (CVAL(cli->inbuf,smb_com) != SMBreadX)) {
 260                         /*
 261                          * We're not coping here with asnyc replies to
 262                          * other calls. Punt here - we need async client
 263                          * libs for this.
 264                          */
 265                         goto read_err;
 266                 }
 267
 268                 /*
 269                  * We know it's a readX reply - ensure we've read the
 270                  * padding bytes also.
 271                  */
 272
 273                 offset = SVAL(cli->inbuf,smb_vwv6);
 274                 if (offset > len) {
 275                         ssize_t ret;
 276                         size_t padbytes = offset - len;
 277                         ret = cli_receive_smb_data(cli,smb_buf(cli->inbuf),padbytes);
 278                         if (ret != padbytes) {
 279                                 goto read_err;
 280                         }
 281                 }
 282         }
 283
 284         return True;
 285
 286   read_err:
 287
 288         cli->smb_rw_error = smb_read_error = READ_ERROR;
 289         close(cli->fd);
 290         cli->fd = -1;
 291         return False;
 292 }
 293
 294 static ssize_t write_socket(int fd, const char *buf, size_t len)
 295 {
 296         ssize_t ret=0;
 297
 298         DEBUG(6,("write_socket(%d,%d)\n",fd,(int)len));
 299         ret = write_data(fd,buf,len);
 300
 301         DEBUG(6,("write_socket(%d,%d) wrote %d\n",fd,(int)len,(int)ret));
 302         if(ret <= 0)
 303                 DEBUG(0,("write_socket: Error writing %d bytes to socket %d: ERRNO = %s\n",
 304                         (int)len, fd, strerror(errno) ));
 305
 306         return(ret);
 307 }
 308
 309 /****************************************************************************
 310  Send an smb to a fd.
 311 ****************************************************************************/
 312
 313 BOOL cli_send_smb(struct cli_state *cli)
 314 {
 315         size_t len;
 316         size_t nwritten=0;
 317         ssize_t ret;
 318         char *buf_out = cli->outbuf;
 319         BOOL enc_on = cli_encryption_on(cli);
 320
 321         /* fd == -1 causes segfaults -- Tom (tom@ninja.nl) */
 322         if (cli->fd == -1) {
 323                 return False;
 324         }
 325
 326         cli_calculate_sign_mac(cli);
 327
 328         if (enc_on) {
 329                 NTSTATUS status = cli_encrypt_message(cli, &buf_out);
 330                 if (!NT_STATUS_IS_OK(status)) {
 331                         close(cli->fd);
 332                         cli->fd = -1;
 333                         cli->smb_rw_error = WRITE_ERROR;
 334                         DEBUG(0,("Error in encrypting client message. Error %s\n",
 335                                 nt_errstr(status) ));
 336                         return False;
 337                 }
 338         }
 339
 340         len = smb_len(buf_out) + 4;
 341
 342         while (nwritten < len) {
 343                 ret = write_socket(cli->fd,buf_out+nwritten,len - nwritten);
 344                 if (ret <= 0) {
 345                         if (enc_on) {
 346                                 cli_free_enc_buffer(cli, buf_out);
 347                         }
 348                         close(cli->fd);
 349                         cli->fd = -1;
 350                         cli->smb_rw_error = WRITE_ERROR;
 351                         DEBUG(0,("Error writing %d bytes to client. %d (%s)\n",
 352                                 (int)len,(int)ret, strerror(errno) ));
 353                         return False;
 354                 }
 355                 nwritten += ret;
 356         }
 357
 358         cli_free_enc_buffer(cli, buf_out);
 359
 360         /* Increment the mid so we can tell between responses. */
 361         cli->mid++;
 362         if (!cli->mid) {
 363                 cli->mid++;
 364         }
 365         return True;
 366 }
 367
 368 /****************************************************************************
 369  Setup basics in a outgoing packet.
 370 ****************************************************************************/
 371
 372 void cli_setup_packet(struct cli_state *cli)
 373 {
 374         cli->rap_error = 0;
 375         SSVAL(cli->outbuf,smb_pid,cli->pid);
 376         SSVAL(cli->outbuf,smb_uid,cli->vuid);
 377         SSVAL(cli->outbuf,smb_mid,cli->mid);
 378         if (cli->protocol > PROTOCOL_CORE) {
 379                 uint16 flags2;
 380                 if (cli->case_sensitive) {
 381                         SCVAL(cli->outbuf,smb_flg,0x0);
 382                 } else {
 383                         /* Default setting, case insensitive. */
 384                         SCVAL(cli->outbuf,smb_flg,0x8);
 385                 }
 386                 flags2 = FLAGS2_LONG_PATH_COMPONENTS;
 387                 if (cli->capabilities & CAP_UNICODE)
 388                         flags2 |= FLAGS2_UNICODE_STRINGS;
 389                 if ((cli->capabilities & CAP_DFS) && cli->dfsroot)
 390                         flags2 |= FLAGS2_DFS_PATHNAMES;
 391                 if (cli->capabilities & CAP_STATUS32)
 392                         flags2 |= FLAGS2_32_BIT_ERROR_CODES;
 393                 if (cli->use_spnego)
 394                         flags2 |= FLAGS2_EXTENDED_SECURITY;
 395                 SSVAL(cli->outbuf,smb_flg2, flags2);
 396         }
 397 }
 398
 399 /****************************************************************************
 400  Setup the bcc length of the packet from a pointer to the end of the data.
 401 ****************************************************************************/
 402
 403 void cli_setup_bcc(struct cli_state *cli, void *p)
 404 {
 405         set_message_bcc(NULL,cli->outbuf, PTR_DIFF(p, smb_buf(cli->outbuf)));
 406 }
 407
 408 /****************************************************************************
 409  Initialise credentials of a client structure.
 410 ****************************************************************************/
 411
 412 void cli_init_creds(struct cli_state *cli, const char *username, const char *domain, const char *password)
 413 {
 414         fstrcpy(cli->domain, domain);
 415         fstrcpy(cli->user_name, username);
 416         pwd_set_cleartext(&cli->pwd, password);
 417         if (!*username) {
 418                 cli->pwd.null_pwd = True;
 419         }
 420
 421         DEBUG(10,("cli_init_creds: user %s domain %s\n", cli->user_name, cli->domain));
 422 }
 423
 424 /****************************************************************************
 425  Set the signing state (used from the command line).
 426 ****************************************************************************/
 427
 428 void cli_setup_signing_state(struct cli_state *cli, int signing_state)
 429 {
 430         if (signing_state == Undefined)
 431                 return;
 432
 433         if (signing_state == False) {
 434                 cli->sign_info.allow_smb_signing = False;
 435                 cli->sign_info.mandatory_signing = False;
 436                 return;
 437         }
 438
 439         cli->sign_info.allow_smb_signing = True;
 440
 441         if (signing_state == Required)
 442                 cli->sign_info.mandatory_signing = True;
 443 }
 444
 445 /****************************************************************************
 446  Initialise a client structure. Always returns a malloc'ed struct.
 447 ****************************************************************************/
 448
 449 struct cli_state *cli_initialise(void)
 450 {
 451         struct cli_state *cli = NULL;
 452
 453         /* Check the effective uid - make sure we are not setuid */
 454         if (is_setuid_root()) {
 455                 DEBUG(0,("libsmb based programs must *NOT* be setuid root.\n"));
 456                 return NULL;
 457         }
 458
 459         cli = SMB_MALLOC_P(struct cli_state);
 460         if (!cli) {
 461                 return NULL;
 462         }
 463
 464         ZERO_STRUCTP(cli);
 465
 466         cli->port = 0;
 467         cli->fd = -1;
 468         cli->cnum = -1;
 469         cli->pid = (uint16)sys_getpid();
 470         cli->mid = 1;
 471         cli->vuid = UID_FIELD_INVALID;
 472         cli->protocol = PROTOCOL_NT1;
 473         cli->timeout = 20000; /* Timeout is in milliseconds. */
 474         cli->bufsize = CLI_BUFFER_SIZE+4;
 475         cli->max_xmit = cli->bufsize;
 476         cli->outbuf = (char *)SMB_MALLOC(cli->bufsize+SAFETY_MARGIN);
 477         cli->inbuf = (char *)SMB_MALLOC(cli->bufsize+SAFETY_MARGIN);
 478         cli->oplock_handler = cli_oplock_ack;
 479         cli->case_sensitive = False;
 480         cli->smb_rw_error = 0;
 481
 482         cli->use_spnego = lp_client_use_spnego();
 483
 484         cli->capabilities = CAP_UNICODE | CAP_STATUS32 | CAP_DFS;
 485
 486         /* Set the CLI_FORCE_DOSERR environment variable to test
 487            client routines using DOS errors instead of STATUS32
 488            ones.  This intended only as a temporary hack. */
 489         if (getenv("CLI_FORCE_DOSERR"))
 490                 cli->force_dos_errors = True;
 491
 492         if (lp_client_signing())
 493                 cli->sign_info.allow_smb_signing = True;
 494
 495         if (lp_client_signing() == Required)
 496                 cli->sign_info.mandatory_signing = True;
 497
 498         if (!cli->outbuf || !cli->inbuf)
 499                 goto error;
 500
 501         if ((cli->mem_ctx = talloc_init("cli based talloc")) == NULL)
 502                 goto error;
 503
 504         memset(cli->outbuf, 0, cli->bufsize);
 505         memset(cli->inbuf, 0, cli->bufsize);
 506
 507
 508 #if defined(DEVELOPER)
 509         /* just because we over-allocate, doesn't mean it's right to use it */
 510         clobber_region(FUNCTION_MACRO, __LINE__, cli->outbuf+cli->bufsize, SAFETY_MARGIN);
 511         clobber_region(FUNCTION_MACRO, __LINE__, cli->inbuf+cli->bufsize, SAFETY_MARGIN);
 512 #endif
 513
 514         /* initialise signing */
 515         cli_null_set_signing(cli);
 516
 517         cli->initialised = 1;
 518
 519         return cli;
 520
 521         /* Clean up after malloc() error */
 522
 523  error:
 524
 525         SAFE_FREE(cli->inbuf);
 526         SAFE_FREE(cli->outbuf);
 527         SAFE_FREE(cli);
 528         return NULL;
 529 }
 530
 531 /****************************************************************************
 532  External interface.
 533  Close an open named pipe over SMB. Free any authentication data.
 534  Returns False if the cli_close call failed.
 535  ****************************************************************************/
 536
 537 BOOL cli_rpc_pipe_close(struct rpc_pipe_client *cli)
 538 {
 539         BOOL ret;
 540
 541         if (!cli) {
 542                 return False;
 543         }
 544
 545         ret = cli_close(cli->cli, cli->fnum);
 546
 547         if (!ret) {
 548                 DEBUG(1,("cli_rpc_pipe_close: cli_close failed on pipe %s, "
 549                          "fnum 0x%x "
 550                          "to machine %s.  Error was %s\n",
 551                          cli->pipe_name,
 552                          (int) cli->fnum,
 553                          cli->cli->desthost,
 554                          cli_errstr(cli->cli)));
 555         }
 556
 557         if (cli->auth.cli_auth_data_free_func) {
 558                 (*cli->auth.cli_auth_data_free_func)(&cli->auth);
 559         }
 560
 561         DEBUG(10,("cli_rpc_pipe_close: closed pipe %s to machine %s\n",
 562                 cli->pipe_name, cli->cli->desthost ));
 563
 564         DLIST_REMOVE(cli->cli->pipe_list, cli);
 565         talloc_destroy(cli->mem_ctx);
 566         return ret;
 567 }
 568
 569 /****************************************************************************
 570  Close all pipes open on this session.
 571 ****************************************************************************/
 572
 573 void cli_nt_pipes_close(struct cli_state *cli)
 574 {
 575         struct rpc_pipe_client *cp, *next;
 576
 577         for (cp = cli->pipe_list; cp; cp = next) {
 578                 next = cp->next;
 579                 cli_rpc_pipe_close(cp);
 580         }
 581 }
 582
 583 /****************************************************************************
 584  Shutdown a client structure.
 585 ****************************************************************************/
 586
 587 void cli_shutdown(struct cli_state *cli)
 588 {
 589         cli_nt_pipes_close(cli);
 590
 591         /*
 592          * tell our peer to free his resources.  Wihtout this, when an
 593          * application attempts to do a graceful shutdown and calls
 594          * smbc_free_context() to clean up all connections, some connections
 595          * can remain active on the peer end, until some (long) timeout period
 596          * later.  This tree disconnect forces the peer to clean up, since the
 597          * connection will be going away.
 598          *
 599          * Also, do not do tree disconnect when cli->smb_rw_error is DO_NOT_DO_TDIS
 600          * the only user for this so far is smbmount which passes opened connection
 601          * down to kernel's smbfs module.
 602          */
 603         if ( (cli->cnum != (uint16)-1) && (cli->smb_rw_error != DO_NOT_DO_TDIS ) ) {
 604                 cli_tdis(cli);
 605         }
 606
 607         SAFE_FREE(cli->outbuf);
 608         SAFE_FREE(cli->inbuf);
 609
 610         cli_free_signing_context(cli);
 611         cli_free_encryption_context(cli);
 612
 613         data_blob_free(&cli->secblob);
 614         data_blob_free(&cli->user_session_key);
 615
 616         if (cli->mem_ctx) {
 617                 talloc_destroy(cli->mem_ctx);
 618                 cli->mem_ctx = NULL;
 619         }
 620
 621         if (cli->fd != -1) {
 622                 close(cli->fd);
 623         }
 624         cli->fd = -1;
 625         cli->smb_rw_error = 0;
 626
 627         SAFE_FREE(cli);
 628 }
 629
 630 /****************************************************************************
 631  Set socket options on a open connection.
 632 ****************************************************************************/
 633
 634 void cli_sockopt(struct cli_state *cli, const char *options)
 635 {
 636         set_socket_options(cli->fd, options);
 637 }
 638
 639 /****************************************************************************
 640  Set the PID to use for smb messages. Return the old pid.
 641 ****************************************************************************/
 642
 643 uint16 cli_setpid(struct cli_state *cli, uint16 pid)
 644 {
 645         uint16 ret = cli->pid;
 646         cli->pid = pid;
 647         return ret;
 648 }
 649
 650 /****************************************************************************
 651  Set the case sensitivity flag on the packets. Returns old state.
 652 ****************************************************************************/
 653
 654 BOOL cli_set_case_sensitive(struct cli_state *cli, BOOL case_sensitive)
 655 {
 656         BOOL ret = cli->case_sensitive;
 657         cli->case_sensitive = case_sensitive;
 658         return ret;
 659 }
 660
 661 /****************************************************************************
 662 Send a keepalive packet to the server
 663 ****************************************************************************/
 664
 665 BOOL cli_send_keepalive(struct cli_state *cli)
 666 {
 667         if (cli->fd == -1) {
 668                 DEBUG(3, ("cli_send_keepalive: fd == -1\n"));
 669                 return False;
 670         }
 671         if (!send_keepalive(cli->fd)) {
 672                 close(cli->fd);
 673                 cli->fd = -1;
 674                 DEBUG(0,("Error sending keepalive packet to client.\n"));
 675                 return False;
 676         }
 677         return True;
 678 }
 679
 680 /****************************************************************************
 681  Send/receive a SMBecho command: ping the server
 682 ****************************************************************************/
 683
 684 BOOL cli_echo(struct cli_state *cli, unsigned char *data, size_t length)
 685 {
 686         char *p;
 687
 688         SMB_ASSERT(length < 1024);
 689
 690         memset(cli->outbuf,'\0',smb_size);
 691         set_message(NULL,cli->outbuf,1,length,True);
 692         SCVAL(cli->outbuf,smb_com,SMBecho);
 693         SSVAL(cli->outbuf,smb_tid,65535);
 694         SSVAL(cli->outbuf,smb_vwv0,1);
 695         cli_setup_packet(cli);
 696         p = smb_buf(cli->outbuf);
 697         memcpy(p, data, length);
 698         p += length;
 699
 700         cli_setup_bcc(cli, p);
 701
 702         cli_send_smb(cli);
 703         if (!cli_receive_smb(cli)) {
 704                 return False;
 705         }
 706
 707         if (cli_is_error(cli)) {
 708                 return False;
 709         }
 710         return True;
 711 }