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                 if (len < 0) {
 101                         return len;
 102                 }
 103
 104                 /* Ignore session keepalive packets. */
 105                 if(CVAL(cli->inbuf,0) != SMBkeepalive) {
 106                         break;
 107                 }
 108         }
 109
 110         if (cli_encryption_on(cli)) {
 111                 NTSTATUS status = cli_decrypt_message(cli);
 112                 if (!NT_STATUS_IS_OK(status)) {
 113                         DEBUG(0, ("SMB decryption failed on incoming packet! Error %s\n",
 114                                 nt_errstr(status)));
 115                         cli->smb_rw_error = SMB_READ_BAD_DECRYPT;
 116                         return -1;
 117                 }
 118         }
 119
 120         show_msg(cli->inbuf);
 121         return len;
 122 }
 123
 124 /****************************************************************************
 125  Recv an smb.
 126 ****************************************************************************/
 127
 128 bool cli_receive_smb(struct cli_state *cli)
 129 {
 130         ssize_t len;
 131
 132         /* fd == -1 causes segfaults -- Tom (tom@ninja.nl) */
 133         if (cli->fd == -1)
 134                 return false;
 135
 136  again:
 137         len = client_receive_smb(cli, 0);
 138
 139         if (len > 0) {
 140                 /* it might be an oplock break request */
 141                 if (!(CVAL(cli->inbuf, smb_flg) & FLAG_REPLY) &&
 142                     CVAL(cli->inbuf,smb_com) == SMBlockingX &&
 143                     SVAL(cli->inbuf,smb_vwv6) == 0 &&
 144                     SVAL(cli->inbuf,smb_vwv7) == 0) {
 145                         if (cli->oplock_handler) {
 146                                 int fnum = SVAL(cli->inbuf,smb_vwv2);
 147                                 unsigned char level = CVAL(cli->inbuf,smb_vwv3+1);
 148                                 if (!cli->oplock_handler(cli, fnum, level)) {
 149                                         return false;
 150                                 }
 151                         }
 152                         /* try to prevent loops */
 153                         SCVAL(cli->inbuf,smb_com,0xFF);
 154                         goto again;
 155                 }
 156         }
 157
 158         /* If the server is not responding, note that now */
 159         if (len < 0) {
 160                 DEBUG(0, ("Receiving SMB: Server stopped responding\n"));
 161                 close(cli->fd);
 162                 cli->fd = -1;
 163                 return false;
 164         }
 165
 166         if (!cli_check_sign_mac(cli, cli->inbuf)) {
 167                 /*
 168                  * If we get a signature failure in sessionsetup, then
 169                  * the server sometimes just reflects the sent signature
 170                  * back to us. Detect this and allow the upper layer to
 171                  * retrieve the correct Windows error message.
 172                  */
 173                 if (CVAL(cli->outbuf,smb_com) == SMBsesssetupX &&
 174                         (smb_len(cli->inbuf) > (smb_ss_field + 8 - 4)) &&
 175                         (SVAL(cli->inbuf,smb_flg2) & FLAGS2_SMB_SECURITY_SIGNATURES) &&
 176                         memcmp(&cli->outbuf[smb_ss_field],&cli->inbuf[smb_ss_field],8) == 0 &&
 177                         cli_is_error(cli)) {
 178
 179                         /*
 180                          * Reflected signature on login error.
 181                          * Set bad sig but don't close fd.
 182                          */
 183                         cli->smb_rw_error = SMB_READ_BAD_SIG;
 184                         return true;
 185                 }
 186
 187                 DEBUG(0, ("SMB Signature verification failed on incoming packet!\n"));
 188                 cli->smb_rw_error = SMB_READ_BAD_SIG;
 189                 close(cli->fd);
 190                 cli->fd = -1;
 191                 return false;
 192         };
 193         return true;
 194 }
 195
 196 /****************************************************************************
 197  Read the data portion of a readX smb.
 198  The timeout is in milliseconds
 199 ****************************************************************************/
 200
 201 ssize_t cli_receive_smb_data(struct cli_state *cli, char *buffer, size_t len)
 202 {
 203         NTSTATUS status;
 204
 205         set_smb_read_error(&cli->smb_rw_error, SMB_READ_OK);
 206
 207         status = read_socket_with_timeout(
 208                 cli->fd, buffer, len, len, cli->timeout, NULL);
 209         if (NT_STATUS_IS_OK(status)) {
 210                 return len;
 211         }
 212
 213         if (NT_STATUS_EQUAL(status, NT_STATUS_END_OF_FILE)) {
 214                 set_smb_read_error(&cli->smb_rw_error, SMB_READ_EOF);
 215                 return -1;
 216         }
 217
 218         if (NT_STATUS_EQUAL(status, NT_STATUS_IO_TIMEOUT)) {
 219                 set_smb_read_error(&cli->smb_rw_error, SMB_READ_TIMEOUT);
 220                 return -1;
 221         }
 222
 223         set_smb_read_error(&cli->smb_rw_error, SMB_READ_ERROR);
 224         return -1;
 225 }
 226
 227 static ssize_t write_socket(int fd, const char *buf, size_t len)
 228 {
 229         ssize_t ret=0;
 230
 231         DEBUG(6,("write_socket(%d,%d)\n",fd,(int)len));
 232         ret = write_data(fd,buf,len);
 233
 234         DEBUG(6,("write_socket(%d,%d) wrote %d\n",fd,(int)len,(int)ret));
 235         if(ret <= 0)
 236                 DEBUG(0,("write_socket: Error writing %d bytes to socket %d: ERRNO = %s\n",
 237                         (int)len, fd, strerror(errno) ));
 238
 239         return(ret);
 240 }
 241
 242 /****************************************************************************
 243  Send an smb to a fd.
 244 ****************************************************************************/
 245
 246 bool cli_send_smb(struct cli_state *cli)
 247 {
 248         size_t len;
 249         size_t nwritten=0;
 250         ssize_t ret;
 251         char *buf_out = cli->outbuf;
 252         bool enc_on = cli_encryption_on(cli);
 253
 254         /* fd == -1 causes segfaults -- Tom (tom@ninja.nl) */
 255         if (cli->fd == -1)
 256                 return false;
 257
 258         cli_calculate_sign_mac(cli, cli->outbuf);
 259
 260         if (enc_on) {
 261                 NTSTATUS status = cli_encrypt_message(cli, cli->outbuf,
 262                                                       &buf_out);
 263                 if (!NT_STATUS_IS_OK(status)) {
 264                         close(cli->fd);
 265                         cli->fd = -1;
 266                         cli->smb_rw_error = SMB_WRITE_ERROR;
 267                         DEBUG(0,("Error in encrypting client message. Error %s\n",
 268                                 nt_errstr(status) ));
 269                         return false;
 270                 }
 271         }
 272
 273         len = smb_len(buf_out) + 4;
 274
 275         while (nwritten < len) {
 276                 ret = write_socket(cli->fd,buf_out+nwritten,len - nwritten);
 277                 if (ret <= 0) {
 278                         if (enc_on) {
 279                                 cli_free_enc_buffer(cli, buf_out);
 280                         }
 281                         close(cli->fd);
 282                         cli->fd = -1;
 283                         cli->smb_rw_error = SMB_WRITE_ERROR;
 284                         DEBUG(0,("Error writing %d bytes to client. %d (%s)\n",
 285                                 (int)len,(int)ret, strerror(errno) ));
 286                         return false;
 287                 }
 288                 nwritten += ret;
 289         }
 290
 291         if (enc_on) {
 292                 cli_free_enc_buffer(cli, buf_out);
 293         }
 294
 295         /* Increment the mid so we can tell between responses. */
 296         cli->mid++;
 297         if (!cli->mid)
 298                 cli->mid++;
 299         return true;
 300 }
 301
 302 /****************************************************************************
 303  Send a "direct" writeX smb to a fd.
 304 ****************************************************************************/
 305
 306 bool cli_send_smb_direct_writeX(struct cli_state *cli,
 307                                 const char *p,
 308                                 size_t extradata)
 309 {
 310         /* First length to send is the offset to the data. */
 311         size_t len = SVAL(cli->outbuf,smb_vwv11) + 4;
 312         size_t nwritten=0;
 313         ssize_t ret;
 314
 315         /* fd == -1 causes segfaults -- Tom (tom@ninja.nl) */
 316         if (cli->fd == -1) {
 317                 return false;
 318         }
 319
 320         if (client_is_signing_on(cli)) {
 321                 DEBUG(0,("cli_send_smb_large: cannot send signed packet.\n"));
 322                 return false;
 323         }
 324
 325         while (nwritten < len) {
 326                 ret = write_socket(cli->fd,cli->outbuf+nwritten,len - nwritten);
 327                 if (ret <= 0) {
 328                         close(cli->fd);
 329                         cli->fd = -1;
 330                         cli->smb_rw_error = SMB_WRITE_ERROR;
 331                         DEBUG(0,("Error writing %d bytes to client. %d (%s)\n",
 332                                 (int)len,(int)ret, strerror(errno) ));
 333                         return false;
 334                 }
 335                 nwritten += ret;
 336         }
 337
 338         /* Now write the extra data. */
 339         nwritten=0;
 340         while (nwritten < extradata) {
 341                 ret = write_socket(cli->fd,p+nwritten,extradata - nwritten);
 342                 if (ret <= 0) {
 343                         close(cli->fd);
 344                         cli->fd = -1;
 345                         cli->smb_rw_error = SMB_WRITE_ERROR;
 346                         DEBUG(0,("Error writing %d extradata "
 347                                 "bytes to client. %d (%s)\n",
 348                                 (int)extradata,(int)ret, strerror(errno) ));
 349                         return false;
 350                 }
 351                 nwritten += ret;
 352         }
 353
 354         /* Increment the mid so we can tell between responses. */
 355         cli->mid++;
 356         if (!cli->mid)
 357                 cli->mid++;
 358         return true;
 359 }
 360
 361 /****************************************************************************
 362  Setup basics in a outgoing packet.
 363 ****************************************************************************/
 364
 365 void cli_setup_packet_buf(struct cli_state *cli, char *buf)
 366 {
 367         uint16 flags2;
 368         cli->rap_error = 0;
 369         SIVAL(buf,smb_rcls,0);
 370         SSVAL(buf,smb_pid,cli->pid);
 371         memset(buf+smb_pidhigh, 0, 12);
 372         SSVAL(buf,smb_uid,cli->vuid);
 373         SSVAL(buf,smb_mid,cli->mid);
 374
 375         if (cli->protocol <= PROTOCOL_CORE) {
 376                 return;
 377         }
 378
 379         if (cli->case_sensitive) {
 380                 SCVAL(buf,smb_flg,0x0);
 381         } else {
 382                 /* Default setting, case insensitive. */
 383                 SCVAL(buf,smb_flg,0x8);
 384         }
 385         flags2 = FLAGS2_LONG_PATH_COMPONENTS;
 386         if (cli->capabilities & CAP_UNICODE)
 387                 flags2 |= FLAGS2_UNICODE_STRINGS;
 388         if ((cli->capabilities & CAP_DFS) && cli->dfsroot)
 389                 flags2 |= FLAGS2_DFS_PATHNAMES;
 390         if (cli->capabilities & CAP_STATUS32)
 391                 flags2 |= FLAGS2_32_BIT_ERROR_CODES;
 392         if (cli->use_spnego)
 393                 flags2 |= FLAGS2_EXTENDED_SECURITY;
 394         SSVAL(buf,smb_flg2, flags2);
 395 }
 396
 397 void cli_setup_packet(struct cli_state *cli)
 398 {
 399         cli_setup_packet_buf(cli, cli->outbuf);
 400 }
 401
 402 /****************************************************************************
 403  Setup the bcc length of the packet from a pointer to the end of the data.
 404 ****************************************************************************/
 405
 406 void cli_setup_bcc(struct cli_state *cli, void *p)
 407 {
 408         set_message_bcc(cli->outbuf, PTR_DIFF(p, smb_buf(cli->outbuf)));
 409 }
 410
 411 /****************************************************************************
 412  Initialise credentials of a client structure.
 413 ****************************************************************************/
 414
 415 void cli_init_creds(struct cli_state *cli, const char *username, const char *domain, const char *password)
 416 {
 417         fstrcpy(cli->domain, domain);
 418         fstrcpy(cli->user_name, username);
 419         pwd_set_cleartext(&cli->pwd, password);
 420         if (!*username) {
 421                 cli->pwd.null_pwd = true;
 422         }
 423
 424         DEBUG(10,("cli_init_creds: user %s domain %s\n", cli->user_name, cli->domain));
 425 }
 426
 427 /****************************************************************************
 428  Set the signing state (used from the command line).
 429 ****************************************************************************/
 430
 431 void cli_setup_signing_state(struct cli_state *cli, int signing_state)
 432 {
 433         if (signing_state == Undefined)
 434                 return;
 435
 436         if (signing_state == false) {
 437                 cli->sign_info.allow_smb_signing = false;
 438                 cli->sign_info.mandatory_signing = false;
 439                 return;
 440         }
 441
 442         cli->sign_info.allow_smb_signing = true;
 443
 444         if (signing_state == Required)
 445                 cli->sign_info.mandatory_signing = true;
 446 }
 447
 448 /****************************************************************************
 449  Initialise a client structure. Always returns a malloc'ed struct.
 450 ****************************************************************************/
 451
 452 struct cli_state *cli_initialise(void)
 453 {
 454         struct cli_state *cli = NULL;
 455
 456         /* Check the effective uid - make sure we are not setuid */
 457         if (is_setuid_root()) {
 458                 DEBUG(0,("libsmb based programs must *NOT* be setuid root.\n"));
 459                 return NULL;
 460         }
 461
 462         cli = talloc(NULL, struct cli_state);
 463         if (!cli) {
 464                 return NULL;
 465         }
 466
 467         ZERO_STRUCTP(cli);
 468
 469         cli->port = 0;
 470         cli->fd = -1;
 471         cli->cnum = -1;
 472         cli->pid = (uint16)sys_getpid();
 473         cli->mid = 1;
 474         cli->vuid = UID_FIELD_INVALID;
 475         cli->protocol = PROTOCOL_NT1;
 476         cli->timeout = 20000; /* Timeout is in milliseconds. */
 477         cli->bufsize = CLI_BUFFER_SIZE+4;
 478         cli->max_xmit = cli->bufsize;
 479         cli->outbuf = (char *)SMB_MALLOC(cli->bufsize+SAFETY_MARGIN);
 480         cli->inbuf = (char *)SMB_MALLOC(cli->bufsize+SAFETY_MARGIN);
 481         cli->oplock_handler = cli_oplock_ack;
 482         cli->case_sensitive = false;
 483         cli->smb_rw_error = SMB_READ_OK;
 484
 485         cli->use_spnego = lp_client_use_spnego();
 486
 487         cli->capabilities = CAP_UNICODE | CAP_STATUS32 | CAP_DFS;
 488
 489         /* Set the CLI_FORCE_DOSERR environment variable to test
 490            client routines using DOS errors instead of STATUS32
 491            ones.  This intended only as a temporary hack. */
 492         if (getenv("CLI_FORCE_DOSERR"))
 493                 cli->force_dos_errors = true;
 494
 495         if (lp_client_signing())
 496                 cli->sign_info.allow_smb_signing = true;
 497
 498         if (lp_client_signing() == Required)
 499                 cli->sign_info.mandatory_signing = true;
 500
 501         if (!cli->outbuf || !cli->inbuf)
 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 SMB_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 != SMB_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         data_blob_free(&cli->secblob);
 612         data_blob_free(&cli->user_session_key);
 613
 614         if (cli->fd != -1) {
 615                 close(cli->fd);
 616         }
 617         cli->fd = -1;
 618         cli->smb_rw_error = SMB_READ_OK;
 619
 620         TALLOC_FREE(cli);
 621 }
 622
 623 /****************************************************************************
 624  Set socket options on a open connection.
 625 ****************************************************************************/
 626
 627 void cli_sockopt(struct cli_state *cli, const char *options)
 628 {
 629         set_socket_options(cli->fd, options);
 630 }
 631
 632 /****************************************************************************
 633  Set the PID to use for smb messages. Return the old pid.
 634 ****************************************************************************/
 635
 636 uint16 cli_setpid(struct cli_state *cli, uint16 pid)
 637 {
 638         uint16 ret = cli->pid;
 639         cli->pid = pid;
 640         return ret;
 641 }
 642
 643 /****************************************************************************
 644  Set the case sensitivity flag on the packets. Returns old state.
 645 ****************************************************************************/
 646
 647 bool cli_set_case_sensitive(struct cli_state *cli, bool case_sensitive)
 648 {
 649         bool ret = cli->case_sensitive;
 650         cli->case_sensitive = case_sensitive;
 651         return ret;
 652 }
 653
 654 /****************************************************************************
 655 Send a keepalive packet to the server
 656 ****************************************************************************/
 657
 658 bool cli_send_keepalive(struct cli_state *cli)
 659 {
 660         if (cli->fd == -1) {
 661                 DEBUG(3, ("cli_send_keepalive: fd == -1\n"));
 662                 return false;
 663         }
 664         if (!send_keepalive(cli->fd)) {
 665                 close(cli->fd);
 666                 cli->fd = -1;
 667                 DEBUG(0,("Error sending keepalive packet to client.\n"));
 668                 return false;
 669         }
 670         return true;
 671 }
 672
 673 /****************************************************************************
 674  Send/receive a SMBecho command: ping the server
 675 ****************************************************************************/
 676
 677 bool cli_echo(struct cli_state *cli, uint16 num_echos,
 678               unsigned char *data, size_t length)
 679 {
 680         char *p;
 681         int i;
 682
 683         SMB_ASSERT(length < 1024);
 684
 685         memset(cli->outbuf,'\0',smb_size);
 686         cli_set_message(cli->outbuf,1,length,true);
 687         SCVAL(cli->outbuf,smb_com,SMBecho);
 688         SSVAL(cli->outbuf,smb_tid,65535);
 689         SSVAL(cli->outbuf,smb_vwv0,num_echos);
 690         cli_setup_packet(cli);
 691         p = smb_buf(cli->outbuf);
 692         memcpy(p, data, length);
 693         p += length;
 694
 695         cli_setup_bcc(cli, p);
 696
 697         cli_send_smb(cli);
 698
 699         for (i=0; i<num_echos; i++) {
 700                 if (!cli_receive_smb(cli)) {
 701                         return false;
 702                 }
 703
 704                 if (cli_is_error(cli)) {
 705                         return false;
 706                 }
 707         }
 708
 709         return true;
 710 }