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, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22
  23 extern int smb_read_error;
  24
  25 /****************************************************************************
  26  Change the timeout (in milliseconds).
  27 ****************************************************************************/
  28
  29 unsigned int cli_set_timeout(struct cli_state *cli, unsigned int timeout)
  30 {
  31         unsigned int old_timeout = cli->timeout;
  32         cli->timeout = timeout;
  33         return old_timeout;
  34 }
  35
  36 /****************************************************************************
  37  Change the port number used to call on.
  38 ****************************************************************************/
  39
  40 int cli_set_port(struct cli_state *cli, int port)
  41 {
  42         cli->port = port;
  43         return port;
  44 }
  45
  46 /****************************************************************************
  47  Read an smb from a fd ignoring all keepalive packets. Note that the buffer
  48  *MUST* be of size BUFFER_SIZE+SAFETY_MARGIN.
  49  The timeout is in milliseconds
  50
  51  This is exactly the same as receive_smb except that it never returns
  52  a session keepalive packet (just as receive_smb used to do).
  53  receive_smb was changed to return keepalives as the oplock processing means this call
  54  should never go into a blocking read.
  55 ****************************************************************************/
  56
  57 static ssize_t client_receive_smb(int fd,char *buffer, unsigned int timeout, size_t maxlen)
  58 {
  59         ssize_t len;
  60
  61         for(;;) {
  62                 len = receive_smb_raw(fd, buffer, timeout, maxlen);
  63
  64                 if (len < 0) {
  65                         DEBUG(10,("client_receive_smb failed\n"));
  66                         show_msg(buffer);
  67                         return len;
  68                 }
  69
  70                 /* Ignore session keepalive packets. */
  71                 if(CVAL(buffer,0) != SMBkeepalive)
  72                         break;
  73         }
  74         show_msg(buffer);
  75         return len;
  76 }
  77
  78 /****************************************************************************
  79  Recv an smb.
  80 ****************************************************************************/
  81
  82 bool cli_receive_smb(struct cli_state *cli)
  83 {
  84         ssize_t len;
  85
  86         /* fd == -1 causes segfaults -- Tom (tom@ninja.nl) */
  87         if (cli->fd == -1)
  88                 return False;
  89
  90  again:
  91         len = client_receive_smb(cli->fd,cli->inbuf,cli->timeout, 0);
  92
  93         if (len > 0) {
  94                 /* it might be an oplock break request */
  95                 if (!(CVAL(cli->inbuf, smb_flg) & FLAG_REPLY) &&
  96                     CVAL(cli->inbuf,smb_com) == SMBlockingX &&
  97                     SVAL(cli->inbuf,smb_vwv6) == 0 &&
  98                     SVAL(cli->inbuf,smb_vwv7) == 0) {
  99                         if (cli->oplock_handler) {
 100                                 int fnum = SVAL(cli->inbuf,smb_vwv2);
 101                                 unsigned char level = CVAL(cli->inbuf,smb_vwv3+1);
 102                                 if (!cli->oplock_handler(cli, fnum, level)) {
 103                                         return False;
 104                                 }
 105                         }
 106                         /* try to prevent loops */
 107                         SCVAL(cli->inbuf,smb_com,0xFF);
 108                         goto again;
 109                 }
 110         }
 111
 112         /* If the server is not responding, note that now */
 113         if (len < 0) {
 114                 DEBUG(0, ("Receiving SMB: Server stopped responding\n"));
 115                 cli->smb_rw_error = smb_read_error;
 116                 close(cli->fd);
 117                 cli->fd = -1;
 118                 return False;
 119         }
 120
 121         if (!cli_check_sign_mac(cli)) {
 122                 /*
 123                  * If we get a signature failure in sessionsetup, then
 124                  * the server sometimes just reflects the sent signature
 125                  * back to us. Detect this and allow the upper layer to
 126                  * retrieve the correct Windows error message.
 127                  */
 128                 if (CVAL(cli->outbuf,smb_com) == SMBsesssetupX &&
 129                         (smb_len(cli->inbuf) > (smb_ss_field + 8 - 4)) &&
 130                         (SVAL(cli->inbuf,smb_flg2) & FLAGS2_SMB_SECURITY_SIGNATURES) &&
 131                         memcmp(&cli->outbuf[smb_ss_field],&cli->inbuf[smb_ss_field],8) == 0 &&
 132                         cli_is_error(cli)) {
 133
 134                         /*
 135                          * Reflected signature on login error.
 136                          * Set bad sig but don't close fd.
 137                          */
 138                         cli->smb_rw_error = READ_BAD_SIG;
 139                         return True;
 140                 }
 141
 142                 DEBUG(0, ("SMB Signature verification failed on incoming packet!\n"));
 143                 cli->smb_rw_error = READ_BAD_SIG;
 144                 close(cli->fd);
 145                 cli->fd = -1;
 146                 return False;
 147         };
 148         return True;
 149 }
 150
 151 /****************************************************************************
 152  Read the data portion of a readX smb.
 153  The timeout is in milliseconds
 154 ****************************************************************************/
 155
 156 ssize_t cli_receive_smb_data(struct cli_state *cli, char *buffer, size_t len)
 157 {
 158         if (cli->timeout > 0) {
 159                 return read_socket_with_timeout(cli->fd, buffer, len, len, cli->timeout);
 160         } else {
 161                 return read_data(cli->fd, buffer, len);
 162         }
 163 }
 164
 165 /****************************************************************************
 166  Read a smb readX header.
 167 ****************************************************************************/
 168
 169 bool cli_receive_smb_readX_header(struct cli_state *cli)
 170 {
 171         ssize_t len, offset;
 172
 173         if (cli->fd == -1)
 174                 return False;
 175
 176  again:
 177
 178         /* Read up to the size of a readX header reply. */
 179         len = client_receive_smb(cli->fd, cli->inbuf, cli->timeout, (smb_size - 4) + 24);
 180
 181         if (len > 0) {
 182                 /* it might be an oplock break request */
 183                 if (!(CVAL(cli->inbuf, smb_flg) & FLAG_REPLY) &&
 184                     CVAL(cli->inbuf,smb_com) == SMBlockingX &&
 185                     SVAL(cli->inbuf,smb_vwv6) == 0 &&
 186                     SVAL(cli->inbuf,smb_vwv7) == 0) {
 187                         ssize_t total_len = smb_len(cli->inbuf);
 188
 189                         if (total_len > CLI_SAMBA_MAX_LARGE_READX_SIZE+SAFETY_MARGIN) {
 190                                 goto read_err;
 191                         }
 192
 193                         /* Read the rest of the data. */
 194                         if ((total_len - len > 0) &&
 195                             !cli_receive_smb_data(cli,cli->inbuf+len,total_len - len)) {
 196                                 goto read_err;
 197                         }
 198
 199                         if (cli->oplock_handler) {
 200                                 int fnum = SVAL(cli->inbuf,smb_vwv2);
 201                                 unsigned char level = CVAL(cli->inbuf,smb_vwv3+1);
 202                                 if (!cli->oplock_handler(cli, fnum, level)) return False;
 203                         }
 204                         /* try to prevent loops */
 205                         SCVAL(cli->inbuf,smb_com,0xFF);
 206                         goto again;
 207                 }
 208         }
 209
 210         /* If it's not the above size it probably was an error packet. */
 211
 212         if ((len == (smb_size - 4) + 24) && !cli_is_error(cli)) {
 213                 /* Check it's a non-chained readX reply. */
 214                 if (!(CVAL(cli->inbuf, smb_flg) & FLAG_REPLY) ||
 215                         (CVAL(cli->inbuf,smb_vwv0) != 0xFF) ||
 216                         (CVAL(cli->inbuf,smb_com) != SMBreadX)) {
 217                         /*
 218                          * We're not coping here with asnyc replies to
 219                          * other calls. Punt here - we need async client
 220                          * libs for this.
 221                          */
 222                         goto read_err;
 223                 }
 224
 225                 /*
 226                  * We know it's a readX reply - ensure we've read the
 227                  * padding bytes also.
 228                  */
 229
 230                 offset = SVAL(cli->inbuf,smb_vwv6);
 231                 if (offset > len) {
 232                         ssize_t ret;
 233                         size_t padbytes = offset - len;
 234                         ret = cli_receive_smb_data(cli,smb_buf(cli->inbuf),padbytes);
 235                         if (ret != padbytes) {
 236                                 goto read_err;
 237                         }
 238                 }
 239         }
 240
 241         return True;
 242
 243   read_err:
 244
 245         cli->smb_rw_error = smb_read_error = READ_ERROR;
 246         close(cli->fd);
 247         cli->fd = -1;
 248         return False;
 249 }
 250
 251 static ssize_t write_socket(int fd, const char *buf, size_t len)
 252 {
 253         ssize_t ret=0;
 254
 255         DEBUG(6,("write_socket(%d,%d)\n",fd,(int)len));
 256         ret = write_data(fd,buf,len);
 257
 258         DEBUG(6,("write_socket(%d,%d) wrote %d\n",fd,(int)len,(int)ret));
 259         if(ret <= 0)
 260                 DEBUG(0,("write_socket: Error writing %d bytes to socket %d: ERRNO = %s\n",
 261                         (int)len, fd, strerror(errno) ));
 262
 263         return(ret);
 264 }
 265
 266 /****************************************************************************
 267  Send an smb to a fd.
 268 ****************************************************************************/
 269
 270 bool cli_send_smb(struct cli_state *cli)
 271 {
 272         size_t len;
 273         size_t nwritten=0;
 274         ssize_t ret;
 275
 276         /* fd == -1 causes segfaults -- Tom (tom@ninja.nl) */
 277         if (cli->fd == -1)
 278                 return False;
 279
 280         cli_calculate_sign_mac(cli);
 281
 282         len = smb_len(cli->outbuf) + 4;
 283
 284         while (nwritten < len) {
 285                 ret = write_socket(cli->fd,cli->outbuf+nwritten,len - nwritten);
 286                 if (ret <= 0) {
 287                         close(cli->fd);
 288                         cli->fd = -1;
 289                         cli->smb_rw_error = WRITE_ERROR;
 290                         DEBUG(0,("Error writing %d bytes to client. %d (%s)\n",
 291                                 (int)len,(int)ret, strerror(errno) ));
 292                         return False;
 293                 }
 294                 nwritten += ret;
 295         }
 296         /* Increment the mid so we can tell between responses. */
 297         cli->mid++;
 298         if (!cli->mid)
 299                 cli->mid++;
 300         return True;
 301 }
 302
 303 /****************************************************************************
 304  Send a "direct" writeX smb to a fd.
 305 ****************************************************************************/
 306
 307 bool cli_send_smb_direct_writeX(struct cli_state *cli,
 308                                 const char *p,
 309                                 size_t extradata)
 310 {
 311         /* First length to send is the offset to the data. */
 312         size_t len = SVAL(cli->outbuf,smb_vwv11) + 4;
 313         size_t nwritten=0;
 314         ssize_t ret;
 315
 316         /* fd == -1 causes segfaults -- Tom (tom@ninja.nl) */
 317         if (cli->fd == -1) {
 318                 return false;
 319         }
 320
 321         if (client_is_signing_on(cli)) {
 322                 DEBUG(0,("cli_send_smb_large: cannot send signed packet.\n"));
 323                 return false;
 324         }
 325
 326         while (nwritten < len) {
 327                 ret = write_socket(cli->fd,cli->outbuf+nwritten,len - nwritten);
 328                 if (ret <= 0) {
 329                         close(cli->fd);
 330                         cli->fd = -1;
 331                         cli->smb_rw_error = WRITE_ERROR;
 332                         DEBUG(0,("Error writing %d bytes to client. %d (%s)\n",
 333                                 (int)len,(int)ret, strerror(errno) ));
 334                         return false;
 335                 }
 336                 nwritten += ret;
 337         }
 338
 339         /* Now write the extra data. */
 340         nwritten=0;
 341         while (nwritten < extradata) {
 342                 ret = write_socket(cli->fd,p+nwritten,extradata - nwritten);
 343                 if (ret <= 0) {
 344                         close(cli->fd);
 345                         cli->fd = -1;
 346                         cli->smb_rw_error = WRITE_ERROR;
 347                         DEBUG(0,("Error writing %d extradata "
 348                                 "bytes to client. %d (%s)\n",
 349                                 (int)extradata,(int)ret, strerror(errno) ));
 350                         return False;
 351                 }
 352                 nwritten += ret;
 353         }
 354
 355         /* Increment the mid so we can tell between responses. */
 356         cli->mid++;
 357         if (!cli->mid)
 358                 cli->mid++;
 359         return true;
 360 }
 361
 362 /****************************************************************************
 363  Setup basics in a outgoing packet.
 364 ****************************************************************************/
 365
 366 void cli_setup_packet(struct cli_state *cli)
 367 {
 368         cli->rap_error = 0;
 369         SSVAL(cli->outbuf,smb_pid,cli->pid);
 370         SSVAL(cli->outbuf,smb_uid,cli->vuid);
 371         SSVAL(cli->outbuf,smb_mid,cli->mid);
 372         if (cli->protocol > PROTOCOL_CORE) {
 373                 uint16 flags2;
 374                 if (cli->case_sensitive) {
 375                         SCVAL(cli->outbuf,smb_flg,0x0);
 376                 } else {
 377                         /* Default setting, case insensitive. */
 378                         SCVAL(cli->outbuf,smb_flg,0x8);
 379                 }
 380                 flags2 = FLAGS2_LONG_PATH_COMPONENTS;
 381                 if (cli->capabilities & CAP_UNICODE)
 382                         flags2 |= FLAGS2_UNICODE_STRINGS;
 383                 if ((cli->capabilities & CAP_DFS) && cli->dfsroot)
 384                         flags2 |= FLAGS2_DFS_PATHNAMES;
 385                 if (cli->capabilities & CAP_STATUS32)
 386                         flags2 |= FLAGS2_32_BIT_ERROR_CODES;
 387                 if (cli->use_spnego)
 388                         flags2 |= FLAGS2_EXTENDED_SECURITY;
 389                 SSVAL(cli->outbuf,smb_flg2, flags2);
 390         }
 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 = SMB_MALLOC_P(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 = 0;
 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         if ((cli->mem_ctx = talloc_init("cli based talloc")) == NULL)
 496                 goto error;
 497
 498         memset(cli->outbuf, 0, cli->bufsize);
 499         memset(cli->inbuf, 0, cli->bufsize);
 500
 501
 502 #if defined(DEVELOPER)
 503         /* just because we over-allocate, doesn't mean it's right to use it */
 504         clobber_region(FUNCTION_MACRO, __LINE__, cli->outbuf+cli->bufsize, SAFETY_MARGIN);
 505         clobber_region(FUNCTION_MACRO, __LINE__, cli->inbuf+cli->bufsize, SAFETY_MARGIN);
 506 #endif
 507
 508         /* initialise signing */
 509         cli_null_set_signing(cli);
 510
 511         cli->initialised = 1;
 512
 513         return cli;
 514
 515         /* Clean up after malloc() error */
 516
 517  error:
 518
 519         SAFE_FREE(cli->inbuf);
 520         SAFE_FREE(cli->outbuf);
 521         SAFE_FREE(cli);
 522         return NULL;
 523 }
 524
 525 /****************************************************************************
 526  External interface.
 527  Close an open named pipe over SMB. Free any authentication data.
 528  Returns False if the cli_close call failed.
 529  ****************************************************************************/
 530
 531 bool cli_rpc_pipe_close(struct rpc_pipe_client *cli)
 532 {
 533         bool ret;
 534
 535         if (!cli) {
 536                 return False;
 537         }
 538
 539         ret = cli_close(cli->cli, cli->fnum);
 540
 541         if (!ret) {
 542                 DEBUG(1,("cli_rpc_pipe_close: cli_close failed on pipe %s, "
 543                          "fnum 0x%x "
 544                          "to machine %s.  Error was %s\n",
 545                          cli->pipe_name,
 546                          (int) cli->fnum,
 547                          cli->cli->desthost,
 548                          cli_errstr(cli->cli)));
 549         }
 550
 551         if (cli->auth.cli_auth_data_free_func) {
 552                 (*cli->auth.cli_auth_data_free_func)(&cli->auth);
 553         }
 554
 555         DEBUG(10,("cli_rpc_pipe_close: closed pipe %s to machine %s\n",
 556                 cli->pipe_name, cli->cli->desthost ));
 557
 558         DLIST_REMOVE(cli->cli->pipe_list, cli);
 559         talloc_destroy(cli->mem_ctx);
 560         return ret;
 561 }
 562
 563 /****************************************************************************
 564  Close all pipes open on this session.
 565 ****************************************************************************/
 566
 567 void cli_nt_pipes_close(struct cli_state *cli)
 568 {
 569         struct rpc_pipe_client *cp, *next;
 570
 571         for (cp = cli->pipe_list; cp; cp = next) {
 572                 next = cp->next;
 573                 cli_rpc_pipe_close(cp);
 574         }
 575 }
 576
 577 /****************************************************************************
 578  Shutdown a client structure.
 579 ****************************************************************************/
 580
 581 void cli_shutdown(struct cli_state *cli)
 582 {
 583         cli_nt_pipes_close(cli);
 584
 585         /*
 586          * tell our peer to free his resources.  Wihtout this, when an
 587          * application attempts to do a graceful shutdown and calls
 588          * smbc_free_context() to clean up all connections, some connections
 589          * can remain active on the peer end, until some (long) timeout period
 590          * later.  This tree disconnect forces the peer to clean up, since the
 591          * connection will be going away.
 592          *
 593          * Also, do not do tree disconnect when cli->smb_rw_error is DO_NOT_DO_TDIS
 594          * the only user for this so far is smbmount which passes opened connection
 595          * down to kernel's smbfs module.
 596          */
 597         if ( (cli->cnum != (uint16)-1) && (cli->smb_rw_error != DO_NOT_DO_TDIS ) ) {
 598                 cli_tdis(cli);
 599         }
 600
 601         SAFE_FREE(cli->outbuf);
 602         SAFE_FREE(cli->inbuf);
 603
 604         cli_free_signing_context(cli);
 605         data_blob_free(&cli->secblob);
 606         data_blob_free(&cli->user_session_key);
 607
 608         if (cli->mem_ctx) {
 609                 talloc_destroy(cli->mem_ctx);
 610                 cli->mem_ctx = NULL;
 611         }
 612
 613         if (cli->fd != -1) {
 614                 close(cli->fd);
 615         }
 616         cli->fd = -1;
 617         cli->smb_rw_error = 0;
 618
 619         SAFE_FREE(cli);
 620 }
 621
 622 /****************************************************************************
 623  Set socket options on a open connection.
 624 ****************************************************************************/
 625
 626 void cli_sockopt(struct cli_state *cli, const char *options)
 627 {
 628         set_socket_options(cli->fd, options);
 629 }
 630
 631 /****************************************************************************
 632  Set the PID to use for smb messages. Return the old pid.
 633 ****************************************************************************/
 634
 635 uint16 cli_setpid(struct cli_state *cli, uint16 pid)
 636 {
 637         uint16 ret = cli->pid;
 638         cli->pid = pid;
 639         return ret;
 640 }
 641
 642 /****************************************************************************
 643  Set the case sensitivity flag on the packets. Returns old state.
 644 ****************************************************************************/
 645
 646 bool cli_set_case_sensitive(struct cli_state *cli, bool case_sensitive)
 647 {
 648         bool ret = cli->case_sensitive;
 649         cli->case_sensitive = case_sensitive;
 650         return ret;
 651 }
 652
 653 /****************************************************************************
 654 Send a keepalive packet to the server
 655 ****************************************************************************/
 656
 657 bool cli_send_keepalive(struct cli_state *cli)
 658 {
 659         if (cli->fd == -1) {
 660                 DEBUG(3, ("cli_send_keepalive: fd == -1\n"));
 661                 return False;
 662         }
 663         if (!send_keepalive(cli->fd)) {
 664                 close(cli->fd);
 665                 cli->fd = -1;
 666                 DEBUG(0,("Error sending keepalive packet to client.\n"));
 667                 return False;
 668         }
 669         return True;
 670 }
 671
 672 /****************************************************************************
 673  Send/receive a SMBecho command: ping the server
 674 ****************************************************************************/
 675
 676 bool cli_echo(struct cli_state *cli, uint16 num_echos,
 677               unsigned char *data, size_t length)
 678 {
 679         char *p;
 680         int i;
 681
 682         SMB_ASSERT(length < 1024);
 683
 684         memset(cli->outbuf,'\0',smb_size);
 685         set_message(cli->outbuf,1,length,True);
 686         SCVAL(cli->outbuf,smb_com,SMBecho);
 687         SSVAL(cli->outbuf,smb_tid,65535);
 688         SSVAL(cli->outbuf,smb_vwv0,num_echos);
 689         cli_setup_packet(cli);
 690         p = smb_buf(cli->outbuf);
 691         memcpy(p, data, length);
 692         p += length;
 693
 694         cli_setup_bcc(cli, p);
 695
 696         cli_send_smb(cli);
 697
 698         for (i=0; i<num_echos; i++) {
 699                 if (!cli_receive_smb(cli)) {
 700                         return False;
 701                 }
 702
 703                 if (cli_is_error(cli)) {
 704                         return False;
 705                 }
 706         }
 707
 708         return True;
 709 }