source/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, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22
  23 /*******************************************************************
  24  Setup the word count and byte count for a client smb message.
  25 ********************************************************************/
  26
  27 int cli_set_message(char *buf,int num_words,int num_bytes,bool zero)
  28 {
  29         if (zero && (num_words || num_bytes)) {
  30                 memset(buf + smb_size,'\0',num_words*2 + num_bytes);
  31         }
  32         SCVAL(buf,smb_wct,num_words);
  33         SSVAL(buf,smb_vwv + num_words*SIZEOFWORD,num_bytes);
  34         smb_setlen(buf,smb_size + num_words*2 + num_bytes - 4);
  35         return (smb_size + num_words*2 + num_bytes);
  36 }
  37
  38 /****************************************************************************
  39  Change the timeout (in milliseconds).
  40 ****************************************************************************/
  41
  42 unsigned int cli_set_timeout(struct cli_state *cli, unsigned int timeout)
  43 {
  44         unsigned int old_timeout = cli->timeout;
  45         cli->timeout = timeout;
  46         return old_timeout;
  47 }
  48
  49 /****************************************************************************
  50  Change the port number used to call on.
  51 ****************************************************************************/
  52
  53 int cli_set_port(struct cli_state *cli, int port)
  54 {
  55         cli->port = port;
  56         return port;
  57 }
  58
  59 /****************************************************************************
  60  Read an smb from a fd ignoring all keepalive packets.
  61  The timeout is in milliseconds
  62
  63  This is exactly the same as receive_smb except that it never returns
  64  a session keepalive packet (just as receive_smb used to do).
  65  receive_smb was changed to return keepalives as the oplock processing means this call
  66  should never go into a blocking read.
  67 ****************************************************************************/
  68
  69 static ssize_t client_receive_smb(struct cli_state *cli, size_t maxlen)
  70 {
  71         size_t len;
  72
  73         for(;;) {
  74                 NTSTATUS status;
  75
  76                 set_smb_read_error(&cli->smb_rw_error, SMB_READ_OK);
  77
  78                 status = receive_smb_raw(cli->fd, cli->inbuf, cli->bufsize,
  79                                         cli->timeout, maxlen, &len);
  80                 if (!NT_STATUS_IS_OK(status)) {
  81                         DEBUG(10,("client_receive_smb failed\n"));
  82                         show_msg(cli->inbuf);
  83
  84                         if (NT_STATUS_EQUAL(status, NT_STATUS_END_OF_FILE)) {
  85                                 set_smb_read_error(&cli->smb_rw_error,
  86                                                    SMB_READ_EOF);
  87                                 return -1;
  88                         }
  89
  90                         if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT)) {
  91                                 set_smb_read_error(&cli->smb_rw_error,
  92                                                    SMB_READ_TIMEOUT);
  93                                 return -1;
  94                         }
  95
  96                         set_smb_read_error(&cli->smb_rw_error, SMB_READ_ERROR);
  97                         return -1;
  98                 }
  99
 100                 /*
 101                  * I don't believe len can be < 0 with NT_STATUS_OK
 102                  * returned above, but this check doesn't hurt. JRA.
 103                  */
 104
 105                 if ((ssize_t)len < 0) {
 106                         return len;
 107                 }
 108
 109                 /* Ignore session keepalive packets. */
 110                 if(CVAL(cli->inbuf,0) != SMBkeepalive) {
 111                         break;
 112                 }
 113         }
 114
 115         if (cli_encryption_on(cli)) {
 116                 NTSTATUS status = cli_decrypt_message(cli);
 117                 if (!NT_STATUS_IS_OK(status)) {
 118                         DEBUG(0, ("SMB decryption failed on incoming packet! Error %s\n",
 119                                 nt_errstr(status)));
 120                         cli->smb_rw_error = SMB_READ_BAD_DECRYPT;
 121                         return -1;
 122                 }
 123         }
 124
 125         show_msg(cli->inbuf);
 126         return len;
 127 }
 128
 129 /****************************************************************************
 130  Recv an smb.
 131 ****************************************************************************/
 132
 133 bool cli_receive_smb(struct cli_state *cli)
 134 {
 135         ssize_t len;
 136
 137         /* fd == -1 causes segfaults -- Tom (tom@ninja.nl) */
 138         if (cli->fd == -1)
 139                 return false;
 140
 141  again:
 142         len = client_receive_smb(cli, 0);
 143
 144         if (len > 0) {
 145                 /* it might be an oplock break request */
 146                 if (!(CVAL(cli->inbuf, smb_flg) & FLAG_REPLY) &&
 147                     CVAL(cli->inbuf,smb_com) == SMBlockingX &&
 148                     SVAL(cli->inbuf,smb_vwv6) == 0 &&
 149                     SVAL(cli->inbuf,smb_vwv7) == 0) {
 150                         if (cli->oplock_handler) {
 151                                 int fnum = SVAL(cli->inbuf,smb_vwv2);
 152                                 unsigned char level = CVAL(cli->inbuf,smb_vwv3+1);
 153                                 if (!cli->oplock_handler(cli, fnum, level)) {
 154                                         return false;
 155                                 }
 156                         }
 157                         /* try to prevent loops */
 158                         SCVAL(cli->inbuf,smb_com,0xFF);
 159                         goto again;
 160                 }
 161         }
 162
 163         /* If the server is not responding, note that now */
 164         if (len < 0) {
 165                 DEBUG(0, ("Receiving SMB: Server stopped responding\n"));
 166                 close(cli->fd);
 167                 cli->fd = -1;
 168                 return false;
 169         }
 170
 171         if (!cli_check_sign_mac(cli, cli->inbuf)) {
 172                 /*
 173                  * If we get a signature failure in sessionsetup, then
 174                  * the server sometimes just reflects the sent signature
 175                  * back to us. Detect this and allow the upper layer to
 176                  * retrieve the correct Windows error message.
 177                  */
 178                 if (CVAL(cli->outbuf,smb_com) == SMBsesssetupX &&
 179                         (smb_len(cli->inbuf) > (smb_ss_field + 8 - 4)) &&
 180                         (SVAL(cli->inbuf,smb_flg2) & FLAGS2_SMB_SECURITY_SIGNATURES) &&
 181                         memcmp(&cli->outbuf[smb_ss_field],&cli->inbuf[smb_ss_field],8) == 0 &&
 182                         cli_is_error(cli)) {
 183
 184                         /*
 185                          * Reflected signature on login error.
 186                          * Set bad sig but don't close fd.
 187                          */
 188                         cli->smb_rw_error = SMB_READ_BAD_SIG;
 189                         return true;
 190                 }
 191
 192                 DEBUG(0, ("SMB Signature verification failed on incoming packet!\n"));
 193                 cli->smb_rw_error = SMB_READ_BAD_SIG;
 194                 close(cli->fd);
 195                 cli->fd = -1;
 196                 return false;
 197         };
 198         return true;
 199 }
 200
 201 /****************************************************************************
 202  Read the data portion of a readX smb.
 203  The timeout is in milliseconds
 204 ****************************************************************************/
 205
 206 ssize_t cli_receive_smb_data(struct cli_state *cli, char *buffer, size_t len)
 207 {
 208         NTSTATUS status;
 209
 210         set_smb_read_error(&cli->smb_rw_error, SMB_READ_OK);
 211
 212         status = read_socket_with_timeout(
 213                 cli->fd, buffer, len, len, cli->timeout, NULL);
 214         if (NT_STATUS_IS_OK(status)) {
 215                 return len;
 216         }
 217
 218         if (NT_STATUS_EQUAL(status, NT_STATUS_END_OF_FILE)) {
 219                 set_smb_read_error(&cli->smb_rw_error, SMB_READ_EOF);
 220                 return -1;
 221         }
 222
 223         if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT)) {
 224                 set_smb_read_error(&cli->smb_rw_error, SMB_READ_TIMEOUT);
 225                 return -1;
 226         }
 227
 228         set_smb_read_error(&cli->smb_rw_error, SMB_READ_ERROR);
 229         return -1;
 230 }
 231
 232 static ssize_t write_socket(int fd, const char *buf, size_t len)
 233 {
 234         ssize_t ret=0;
 235
 236         DEBUG(6,("write_socket(%d,%d)\n",fd,(int)len));
 237         ret = write_data(fd,buf,len);
 238
 239         DEBUG(6,("write_socket(%d,%d) wrote %d\n",fd,(int)len,(int)ret));
 240         if(ret <= 0)
 241                 DEBUG(0,("write_socket: Error writing %d bytes to socket %d: ERRNO = %s\n",
 242                         (int)len, fd, strerror(errno) ));
 243
 244         return(ret);
 245 }
 246
 247 /****************************************************************************
 248  Send an smb to a fd.
 249 ****************************************************************************/
 250
 251 bool cli_send_smb(struct cli_state *cli)
 252 {
 253         size_t len;
 254         size_t nwritten=0;
 255         ssize_t ret;
 256         char *buf_out = cli->outbuf;
 257         bool enc_on = cli_encryption_on(cli);
 258
 259         /* fd == -1 causes segfaults -- Tom (tom@ninja.nl) */
 260         if (cli->fd == -1)
 261                 return false;
 262
 263         cli_calculate_sign_mac(cli, cli->outbuf);
 264
 265         if (enc_on) {
 266                 NTSTATUS status = cli_encrypt_message(cli, cli->outbuf,
 267                                                       &buf_out);
 268                 if (!NT_STATUS_IS_OK(status)) {
 269                         close(cli->fd);
 270                         cli->fd = -1;
 271                         cli->smb_rw_error = SMB_WRITE_ERROR;
 272                         DEBUG(0,("Error in encrypting client message. Error %s\n",
 273                                 nt_errstr(status) ));
 274                         return false;
 275                 }
 276         }
 277
 278         len = smb_len(buf_out) + 4;
 279
 280         while (nwritten < len) {
 281                 ret = write_socket(cli->fd,buf_out+nwritten,len - nwritten);
 282                 if (ret <= 0) {
 283                         if (enc_on) {
 284                                 cli_free_enc_buffer(cli, buf_out);
 285                         }
 286                         close(cli->fd);
 287                         cli->fd = -1;
 288                         cli->smb_rw_error = SMB_WRITE_ERROR;
 289                         DEBUG(0,("Error writing %d bytes to client. %d (%s)\n",
 290                                 (int)len,(int)ret, strerror(errno) ));
 291                         return false;
 292                 }
 293                 nwritten += ret;
 294         }
 295
 296         if (enc_on) {
 297                 cli_free_enc_buffer(cli, buf_out);
 298         }
 299
 300         /* Increment the mid so we can tell between responses. */
 301         cli->mid++;
 302         if (!cli->mid)
 303                 cli->mid++;
 304         return true;
 305 }
 306
 307 /****************************************************************************
 308  Send a "direct" writeX smb to a fd.
 309 ****************************************************************************/
 310
 311 bool cli_send_smb_direct_writeX(struct cli_state *cli,
 312                                 const char *p,
 313                                 size_t extradata)
 314 {
 315         /* First length to send is the offset to the data. */
 316         size_t len = SVAL(cli->outbuf,smb_vwv11) + 4;
 317         size_t nwritten=0;
 318         struct iovec iov[2];
 319
 320         /* fd == -1 causes segfaults -- Tom (tom@ninja.nl) */
 321         if (cli->fd == -1) {
 322                 return false;
 323         }
 324
 325         if (client_is_signing_on(cli)) {
 326                 DEBUG(0,("cli_send_smb_large: cannot send signed packet.\n"));
 327                 return false;
 328         }
 329
 330         iov[0].iov_base = cli->outbuf;
 331         iov[0].iov_len = len;
 332         iov[1].iov_base = CONST_DISCARD(char *, p);
 333         iov[1].iov_len = extradata;
 334
 335         nwritten = write_data_iov(cli->fd, iov, 2);
 336         if (nwritten < (len + extradata)) {
 337                 close(cli->fd);
 338                 cli->fd = -1;
 339                 cli->smb_rw_error = SMB_WRITE_ERROR;
 340                 DEBUG(0,("Error writing %d bytes to client. (%s)\n",
 341                          (int)(len+extradata), strerror(errno)));
 342                 return false;
 343         }
 344
 345         /* Increment the mid so we can tell between responses. */
 346         cli->mid++;
 347         if (!cli->mid)
 348                 cli->mid++;
 349         return true;
 350 }
 351
 352 /****************************************************************************
 353  Setup basics in a outgoing packet.
 354 ****************************************************************************/
 355
 356 void cli_setup_packet_buf(struct cli_state *cli, char *buf)
 357 {
 358         uint16 flags2;
 359         cli->rap_error = 0;
 360         SIVAL(buf,smb_rcls,0);
 361         SSVAL(buf,smb_pid,cli->pid);
 362         memset(buf+smb_pidhigh, 0, 12);
 363         SSVAL(buf,smb_uid,cli->vuid);
 364         SSVAL(buf,smb_mid,cli->mid);
 365
 366         if (cli->protocol <= PROTOCOL_CORE) {
 367                 return;
 368         }
 369
 370         if (cli->case_sensitive) {
 371                 SCVAL(buf,smb_flg,0x0);
 372         } else {
 373                 /* Default setting, case insensitive. */
 374                 SCVAL(buf,smb_flg,0x8);
 375         }
 376         flags2 = FLAGS2_LONG_PATH_COMPONENTS;
 377         if (cli->capabilities & CAP_UNICODE)
 378                 flags2 |= FLAGS2_UNICODE_STRINGS;
 379         if ((cli->capabilities & CAP_DFS) && cli->dfsroot)
 380                 flags2 |= FLAGS2_DFS_PATHNAMES;
 381         if (cli->capabilities & CAP_STATUS32)
 382                 flags2 |= FLAGS2_32_BIT_ERROR_CODES;
 383         if (cli->use_spnego)
 384                 flags2 |= FLAGS2_EXTENDED_SECURITY;
 385         SSVAL(buf,smb_flg2, flags2);
 386 }
 387
 388 void cli_setup_packet(struct cli_state *cli)
 389 {
 390         cli_setup_packet_buf(cli, cli->outbuf);
 391 }
 392
 393 /****************************************************************************
 394  Setup the bcc length of the packet from a pointer to the end of the data.
 395 ****************************************************************************/
 396
 397 void cli_setup_bcc(struct cli_state *cli, void *p)
 398 {
 399         set_message_bcc(cli->outbuf, PTR_DIFF(p, smb_buf(cli->outbuf)));
 400 }
 401
 402 /****************************************************************************
 403  Initialise credentials of a client structure.
 404 ****************************************************************************/
 405
 406 void cli_init_creds(struct cli_state *cli, const char *username, const char *domain, const char *password)
 407 {
 408         fstrcpy(cli->domain, domain);
 409         fstrcpy(cli->user_name, username);
 410         pwd_set_cleartext(&cli->pwd, password);
 411         if (!*username) {
 412                 cli->pwd.null_pwd = true;
 413         }
 414
 415         DEBUG(10,("cli_init_creds: user %s domain %s\n", cli->user_name, cli->domain));
 416 }
 417
 418 /****************************************************************************
 419  Set the signing state (used from the command line).
 420 ****************************************************************************/
 421
 422 void cli_setup_signing_state(struct cli_state *cli, int signing_state)
 423 {
 424         if (signing_state == Undefined)
 425                 return;
 426
 427         if (signing_state == false) {
 428                 cli->sign_info.allow_smb_signing = false;
 429                 cli->sign_info.mandatory_signing = false;
 430                 return;
 431         }
 432
 433         cli->sign_info.allow_smb_signing = true;
 434
 435         if (signing_state == Required)
 436                 cli->sign_info.mandatory_signing = true;
 437 }
 438
 439 /****************************************************************************
 440  Initialise a client structure. Always returns a malloc'ed struct.
 441 ****************************************************************************/
 442
 443 struct cli_state *cli_initialise(void)
 444 {
 445         struct cli_state *cli = NULL;
 446
 447         /* Check the effective uid - make sure we are not setuid */
 448         if (is_setuid_root()) {
 449                 DEBUG(0,("libsmb based programs must *NOT* be setuid root.\n"));
 450                 return NULL;
 451         }
 452
 453         cli = talloc(NULL, struct cli_state);
 454         if (!cli) {
 455                 return NULL;
 456         }
 457
 458         ZERO_STRUCTP(cli);
 459
 460         cli->port = 0;
 461         cli->fd = -1;
 462         cli->cnum = -1;
 463         cli->pid = (uint16)sys_getpid();
 464         cli->mid = 1;
 465         cli->vuid = UID_FIELD_INVALID;
 466         cli->protocol = PROTOCOL_NT1;
 467         cli->timeout = 20000; /* Timeout is in milliseconds. */
 468         cli->bufsize = CLI_BUFFER_SIZE+4;
 469         cli->max_xmit = cli->bufsize;
 470         cli->outbuf = (char *)SMB_MALLOC(cli->bufsize+SAFETY_MARGIN);
 471         cli->inbuf = (char *)SMB_MALLOC(cli->bufsize+SAFETY_MARGIN);
 472         cli->oplock_handler = cli_oplock_ack;
 473         cli->case_sensitive = false;
 474         cli->smb_rw_error = SMB_READ_OK;
 475
 476         cli->use_spnego = lp_client_use_spnego();
 477
 478         cli->capabilities = CAP_UNICODE | CAP_STATUS32 | CAP_DFS;
 479
 480         /* Set the CLI_FORCE_DOSERR environment variable to test
 481            client routines using DOS errors instead of STATUS32
 482            ones.  This intended only as a temporary hack. */
 483         if (getenv("CLI_FORCE_DOSERR"))
 484                 cli->force_dos_errors = true;
 485
 486         if (lp_client_signing())
 487                 cli->sign_info.allow_smb_signing = true;
 488
 489         if (lp_client_signing() == Required)
 490                 cli->sign_info.mandatory_signing = true;
 491
 492         if (!cli->outbuf || !cli->inbuf)
 493                 goto error;
 494
 495         memset(cli->outbuf, 0, cli->bufsize);
 496         memset(cli->inbuf, 0, cli->bufsize);
 497
 498
 499 #if defined(DEVELOPER)
 500         /* just because we over-allocate, doesn't mean it's right to use it */
 501         clobber_region(FUNCTION_MACRO, __LINE__, cli->outbuf+cli->bufsize, SAFETY_MARGIN);
 502         clobber_region(FUNCTION_MACRO, __LINE__, cli->inbuf+cli->bufsize, SAFETY_MARGIN);
 503 #endif
 504
 505         /* initialise signing */
 506         cli_null_set_signing(cli);
 507
 508         cli->initialised = 1;
 509
 510         return cli;
 511
 512         /* Clean up after malloc() error */
 513
 514  error:
 515
 516         SAFE_FREE(cli->inbuf);
 517         SAFE_FREE(cli->outbuf);
 518         SAFE_FREE(cli);
 519         return NULL;
 520 }
 521
 522 /****************************************************************************
 523  External interface.
 524  Close an open named pipe over SMB. Free any authentication data.
 525  Returns false if the cli_close call failed.
 526  ****************************************************************************/
 527
 528 bool cli_rpc_pipe_close(struct rpc_pipe_client *cli)
 529 {
 530         bool ret;
 531
 532         if (!cli) {
 533                 return false;
 534         }
 535
 536         ret = cli_close(cli->cli, cli->fnum);
 537
 538         if (!ret) {
 539                 DEBUG(1,("cli_rpc_pipe_close: cli_close failed on pipe %s, "
 540                          "fnum 0x%x "
 541                          "to machine %s.  Error was %s\n",
 542                          cli->pipe_name,
 543                          (int) cli->fnum,
 544                          cli->cli->desthost,
 545                          cli_errstr(cli->cli)));
 546         }
 547
 548         if (cli->auth.cli_auth_data_free_func) {
 549                 (*cli->auth.cli_auth_data_free_func)(&cli->auth);
 550         }
 551
 552         DEBUG(10,("cli_rpc_pipe_close: closed pipe %s to machine %s\n",
 553                 cli->pipe_name, cli->cli->desthost ));
 554
 555         DLIST_REMOVE(cli->cli->pipe_list, cli);
 556         talloc_destroy(cli->mem_ctx);
 557         return ret;
 558 }
 559
 560 /****************************************************************************
 561  Close all pipes open on this session.
 562 ****************************************************************************/
 563
 564 void cli_nt_pipes_close(struct cli_state *cli)
 565 {
 566         struct rpc_pipe_client *cp, *next;
 567
 568         for (cp = cli->pipe_list; cp; cp = next) {
 569                 next = cp->next;
 570                 cli_rpc_pipe_close(cp);
 571         }
 572 }
 573
 574 /****************************************************************************
 575  Shutdown a client structure.
 576 ****************************************************************************/
 577
 578 void cli_shutdown(struct cli_state *cli)
 579 {
 580         cli_nt_pipes_close(cli);
 581
 582         /*
 583          * tell our peer to free his resources.  Wihtout this, when an
 584          * application attempts to do a graceful shutdown and calls
 585          * smbc_free_context() to clean up all connections, some connections
 586          * can remain active on the peer end, until some (long) timeout period
 587          * later.  This tree disconnect forces the peer to clean up, since the
 588          * connection will be going away.
 589          *
 590          * Also, do not do tree disconnect when cli->smb_rw_error is SMB_DO_NOT_DO_TDIS
 591          * the only user for this so far is smbmount which passes opened connection
 592          * down to kernel's smbfs module.
 593          */
 594         if ( (cli->cnum != (uint16)-1) && (cli->smb_rw_error != SMB_DO_NOT_DO_TDIS ) ) {
 595                 cli_tdis(cli);
 596         }
 597
 598         SAFE_FREE(cli->outbuf);
 599         SAFE_FREE(cli->inbuf);
 600
 601         cli_free_signing_context(cli);
 602         data_blob_free(&cli->secblob);
 603         data_blob_free(&cli->user_session_key);
 604
 605         if (cli->fd != -1) {
 606                 close(cli->fd);
 607         }
 608         cli->fd = -1;
 609         cli->smb_rw_error = SMB_READ_OK;
 610
 611         TALLOC_FREE(cli);
 612 }
 613
 614 /****************************************************************************
 615  Set socket options on a open connection.
 616 ****************************************************************************/
 617
 618 void cli_sockopt(struct cli_state *cli, const char *options)
 619 {
 620         set_socket_options(cli->fd, options);
 621 }
 622
 623 /****************************************************************************
 624  Set the PID to use for smb messages. Return the old pid.
 625 ****************************************************************************/
 626
 627 uint16 cli_setpid(struct cli_state *cli, uint16 pid)
 628 {
 629         uint16 ret = cli->pid;
 630         cli->pid = pid;
 631         return ret;
 632 }
 633
 634 /****************************************************************************
 635  Set the case sensitivity flag on the packets. Returns old state.
 636 ****************************************************************************/
 637
 638 bool cli_set_case_sensitive(struct cli_state *cli, bool case_sensitive)
 639 {
 640         bool ret = cli->case_sensitive;
 641         cli->case_sensitive = case_sensitive;
 642         return ret;
 643 }
 644
 645 /****************************************************************************
 646 Send a keepalive packet to the server
 647 ****************************************************************************/
 648
 649 bool cli_send_keepalive(struct cli_state *cli)
 650 {
 651         if (cli->fd == -1) {
 652                 DEBUG(3, ("cli_send_keepalive: fd == -1\n"));
 653                 return false;
 654         }
 655         if (!send_keepalive(cli->fd)) {
 656                 close(cli->fd);
 657                 cli->fd = -1;
 658                 DEBUG(0,("Error sending keepalive packet to client.\n"));
 659                 return false;
 660         }
 661         return true;
 662 }
 663
 664 /****************************************************************************
 665  Send/receive a SMBecho command: ping the server
 666 ****************************************************************************/
 667
 668 bool cli_echo(struct cli_state *cli, uint16 num_echos,
 669               unsigned char *data, size_t length)
 670 {
 671         char *p;
 672         int i;
 673
 674         SMB_ASSERT(length < 1024);
 675
 676         memset(cli->outbuf,'\0',smb_size);
 677         cli_set_message(cli->outbuf,1,length,true);
 678         SCVAL(cli->outbuf,smb_com,SMBecho);
 679         SSVAL(cli->outbuf,smb_tid,65535);
 680         SSVAL(cli->outbuf,smb_vwv0,num_echos);
 681         cli_setup_packet(cli);
 682         p = smb_buf(cli->outbuf);
 683         memcpy(p, data, length);
 684         p += length;
 685
 686         cli_setup_bcc(cli, p);
 687
 688         cli_send_smb(cli);
 689
 690         for (i=0; i<num_echos; i++) {
 691                 if (!cli_receive_smb(cli)) {
 692                         return false;
 693                 }
 694
 695                 if (cli_is_error(cli)) {
 696                         return false;
 697                 }
 698         }
 699
 700         return true;
 701 }