lib/telnet.c

   1 /*****************************************************************************
   2  *                                  _   _ ____  _
   3  *  Project                     ___| | | |  _ \| |
   4  *                             / __| | | | |_) | |
   5  *                            | (__| |_| |  _ <| |___
   6  *                             \___|\___/|_| \_\_____|
   7  *
   8  *  The contents of this file are subject to the Mozilla Public License
   9  *  Version 1.0 (the "License"); you may not use this file except in
  10  *  compliance with the License. You may obtain a copy of the License at
  11  *  http://www.mozilla.org/MPL/
  12  *
  13  *  Software distributed under the License is distributed on an "AS IS"
  14  *  basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
  15  *  License for the specific language governing rights and limitations
  16  *  under the License.
  17  *
  18  *  The Original Code is Curl.
  19  *
  20  *  The Initial Developer of the Original Code is Daniel Stenberg.
  21  *
  22  *  Portions created by the Initial Developer are Copyright (C) 1998.
  23  *  All Rights Reserved.
  24  *
  25  * ------------------------------------------------------------
  26  * Main author:
  27  * - Daniel Stenberg <Daniel.Stenberg@haxx.nu>
  28  *
  29  *      http://curl.haxx.nu
  30  *
  31  * $Source: /cvsroot/curl/curl/lib/telnet.c,v $
  32  * $Revision: 1.1.1.1 $
  33  * $Date: 1999-12-29 14:21:38 $
  34  * $Author: bagder $
  35  * $State: Exp $
  36  * $Locker:  $
  37  *
  38  * ------------------------------------------------------------
  39  *
  40  * This implementation of the TELNET protocol is written by
  41  * Linus Nielsen <Linus.Nielsen@haxx.nu>,
  42  * with some code snippets stolen from the BSD Telnet client.
  43  *
  44  * The negotiation is performed according to RFC 1143 (D. Bernstein,
  45  * "The Q Method of Implementing TELNET Option Negotiation")
  46  *
  47  ****************************************************************************/
  48
  49 /* -- WIN32 approved -- */
  50 #include <stdio.h>
  51 #include <string.h>
  52 #include <stdarg.h>
  53 #include <stdlib.h>
  54 #include <ctype.h>
  55 #include <sys/types.h>
  56 #include <sys/stat.h>
  57
  58 #include <errno.h>
  59
  60 #include "setup.h"
  61
  62 #if defined(WIN32) && !defined(__GNUC__) || defined(__MINGW32__)
  63 #include <winsock.h>
  64 #include <time.h>
  65 #include <io.h>
  66 #else
  67 #ifdef HAVE_SYS_SOCKET_H
  68 #include <sys/socket.h>
  69 #endif
  70 #include <netinet/in.h>
  71 #include <sys/time.h>
  72 #include <sys/resource.h>
  73 #ifdef HAVE_UNISTD_H
  74 #include <unistd.h>
  75 #endif
  76 #include <netdb.h>
  77 #ifdef HAVE_ARPA_INET_H
  78 #include <arpa/inet.h>
  79 #endif
  80 #ifdef HAVE_NET_IF_H
  81 #include <net/if.h>
  82 #endif
  83 #include <sys/ioctl.h>
  84 #include <signal.h>
  85
  86 #ifdef HAVE_SYS_PARAM_H
  87 #include <sys/param.h>
  88 #endif
  89
  90 #ifdef HAVE_SYS_SELECT_H
  91 #include <sys/select.h>
  92 #endif
  93
  94
  95 #endif
  96
  97 #include "urldata.h"
  98 #include <curl/curl.h>
  99 #include "download.h"
 100 #include "sendf.h"
 101 #include "formdata.h"
 102 #include "progress.h"
 103
 104 #define _MPRINTF_REPLACE /* use our functions only */
 105 #include <curl/mprintf.h>
 106
 107 #define  TELOPTS
 108 #define  TELCMDS
 109 #define  SLC_NAMES
 110
 111 #include "arpa_telnet.h"
 112
 113 #define SUBBUFSIZE 512
 114
 115 #define  SB_CLEAR()  subpointer = subbuffer;
 116 #define  SB_TERM()   { subend = subpointer; SB_CLEAR(); }
 117 #define  SB_ACCUM(c) if (subpointer < (subbuffer+sizeof subbuffer)) { \
 118             *subpointer++ = (c); \
 119          }
 120
 121 #define  SB_GET() ((*subpointer++)&0xff)
 122 #define  SB_PEEK()   ((*subpointer)&0xff)
 123 #define  SB_EOF() (subpointer >= subend)
 124 #define  SB_LEN() (subend - subpointer)
 125
 126 void telwrite(struct UrlData *data,
 127               unsigned char *buffer,    /* Data to write */
 128               int count);               /* Number of bytes to write */
 129
 130 void telrcv(struct UrlData *data,
 131             unsigned char *inbuf,       /* Data received from socket */
 132             int count);                 /* Number of bytes received */
 133
 134 static void printoption(struct UrlData *data,
 135                         const char *direction,
 136                         int cmd, int option);
 137
 138 static void negotiate(struct UrlData *data);
 139 static void send_negotiation(struct UrlData *data, int cmd, int option);
 140 static void set_local_option(struct UrlData *data, int cmd, int option);
 141 static void set_remote_option(struct UrlData *data, int cmd, int option);
 142
 143 static void printsub(struct UrlData *data,
 144                      int direction, unsigned char *pointer, int length);
 145 static void suboption(struct UrlData *data);
 146
 147 /* suboptions */
 148 static char subbuffer[SUBBUFSIZE];
 149 static char *subpointer, *subend;    /* buffer for sub-options */
 150
 151 /*
 152  * Telnet receiver states for fsm
 153  */
 154 static enum
 155 {
 156    TS_DATA = 0,
 157    TS_IAC,
 158    TS_WILL,
 159    TS_WONT,
 160    TS_DO,
 161    TS_DONT,
 162    TS_CR,
 163    TS_SB,   /* sub-option collection */
 164    TS_SE   /* looking for sub-option end */
 165 } telrcv_state;
 166
 167 /* For negotiation compliant to RFC 1143 */
 168 #define NO      0
 169 #define YES     1
 170 #define WANTYES 2
 171 #define WANTNO  3
 172
 173 #define EMPTY    0
 174 #define OPPOSITE 1
 175
 176 static int us[256];
 177 static int usq[256];
 178 static int us_preferred[256];
 179 static int him[256];
 180 static int himq[256];
 181 static int him_preferred[256];
 182
 183 void init_telnet(struct UrlData *data)
 184 {
 185    telrcv_state = TS_DATA;
 186
 187    /* Init suboptions */
 188    SB_CLEAR();
 189
 190    /* Set all options to NO */
 191    memset(us, NO, 256);
 192    memset(usq, NO, 256);
 193    memset(us_preferred, NO, 256);
 194    memset(him, NO, 256);
 195    memset(himq, NO, 256);
 196    memset(him_preferred, NO, 256);
 197
 198    /* Set the options we want */
 199    us_preferred[TELOPT_BINARY] = YES;
 200    us_preferred[TELOPT_SGA] = YES;
 201    him_preferred[TELOPT_BINARY] = YES;
 202    him_preferred[TELOPT_SGA] = YES;
 203
 204    /* Start negotiating */
 205    negotiate(data);
 206 }
 207
 208 static void negotiate(struct UrlData *data)
 209 {
 210    int i;
 211
 212    for(i = 0;i < NTELOPTS;i++)
 213    {
 214       if(us_preferred[i] == YES)
 215          set_local_option(data, i, YES);
 216
 217       if(him_preferred[i] == YES)
 218          set_remote_option(data, i, YES);
 219    }
 220 }
 221
 222 static void printoption(struct UrlData *data,
 223                         const char *direction, int cmd, int option)
 224 {
 225    char *fmt;
 226    char *opt;
 227
 228    if (data->conf & CONF_VERBOSE)
 229    {
 230       if (cmd == IAC)
 231       {
 232          if (TELCMD_OK(option))
 233             printf("%s IAC %s\n", direction, TELCMD(option));
 234          else
 235             printf("%s IAC %d\n", direction, option);
 236       }
 237       else
 238       {
 239          fmt = (cmd == WILL) ? "WILL" : (cmd == WONT) ? "WONT" :
 240             (cmd == DO) ? "DO" : (cmd == DONT) ? "DONT" : 0;
 241          if (fmt)
 242          {
 243             if (TELOPT_OK(option))
 244                opt = TELOPT(option);
 245             else if (option == TELOPT_EXOPL)
 246                opt = "EXOPL";
 247             else
 248                opt = NULL;
 249
 250             if(opt)
 251                printf("%s %s %s\n", direction, fmt, opt);
 252             else
 253                printf("%s %s %d\n", direction, fmt, option);
 254          }
 255          else
 256             printf("%s %d %d\n", direction, cmd, option);
 257       }
 258    }
 259 }
 260
 261 static void send_negotiation(struct UrlData *data, int cmd, int option)
 262 {
 263    unsigned char buf[3];
 264
 265    buf[0] = IAC;
 266    buf[1] = cmd;
 267    buf[2] = option;
 268
 269    swrite(data->firstsocket, buf, 3);
 270
 271    printoption(data, "SENT", cmd, option);
 272 }
 273
 274 void set_remote_option(struct UrlData *data, int option, int newstate)
 275 {
 276    if(newstate == YES)
 277    {
 278       switch(him[option])
 279       {
 280       case NO:
 281          him[option] = WANTYES;
 282          send_negotiation(data, DO, option);
 283          break;
 284
 285       case YES:
 286          /* Already enabled */
 287          break;
 288
 289       case WANTNO:
 290          switch(himq[option])
 291          {
 292          case EMPTY:
 293             /* Already negotiating for YES, queue the request */
 294             himq[option] = OPPOSITE;
 295             break;
 296          case OPPOSITE:
 297             /* Error: already queued an enable request */
 298             break;
 299          }
 300          break;
 301
 302       case WANTYES:
 303          switch(himq[option])
 304          {
 305          case EMPTY:
 306             /* Error: already negotiating for enable */
 307             break;
 308          case OPPOSITE:
 309             himq[option] = EMPTY;
 310             break;
 311          }
 312          break;
 313       }
 314    }
 315    else /* NO */
 316    {
 317       switch(him[option])
 318       {
 319       case NO:
 320          /* Already disabled */
 321          break;
 322
 323       case YES:
 324          him[option] = WANTNO;
 325          send_negotiation(data, DONT, option);
 326          break;
 327
 328       case WANTNO:
 329          switch(himq[option])
 330          {
 331          case EMPTY:
 332             /* Already negotiating for NO */
 333             break;
 334          case OPPOSITE:
 335             himq[option] = EMPTY;
 336             break;
 337          }
 338          break;
 339
 340       case WANTYES:
 341          switch(himq[option])
 342          {
 343          case EMPTY:
 344             himq[option] = OPPOSITE;
 345             break;
 346          case OPPOSITE:
 347             break;
 348          }
 349          break;
 350       }
 351    }
 352 }
 353
 354 void rec_will(struct UrlData *data, int option)
 355 {
 356    switch(him[option])
 357    {
 358    case NO:
 359       if(him_preferred[option] == YES)
 360       {
 361          him[option] = YES;
 362          send_negotiation(data, DO, option);
 363       }
 364       else
 365       {
 366          send_negotiation(data, DONT, option);
 367       }
 368       break;
 369
 370    case YES:
 371       /* Already enabled */
 372       break;
 373
 374    case WANTNO:
 375       switch(himq[option])
 376       {
 377       case EMPTY:
 378          /* Error: DONT answered by WILL */
 379          him[option] = NO;
 380          break;
 381       case OPPOSITE:
 382          /* Error: DONT answered by WILL */
 383          him[option] = YES;
 384          himq[option] = EMPTY;
 385          break;
 386       }
 387       break;
 388
 389    case WANTYES:
 390       switch(himq[option])
 391       {
 392       case EMPTY:
 393          him[option] = YES;
 394          break;
 395       case OPPOSITE:
 396          him[option] = WANTNO;
 397          himq[option] = EMPTY;
 398          send_negotiation(data, DONT, option);
 399          break;
 400       }
 401       break;
 402    }
 403 }
 404
 405 void rec_wont(struct UrlData *data, int option)
 406 {
 407    switch(him[option])
 408    {
 409    case NO:
 410       /* Already disabled */
 411       break;
 412
 413    case YES:
 414       him[option] = NO;
 415       send_negotiation(data, DONT, option);
 416       break;
 417
 418    case WANTNO:
 419       switch(himq[option])
 420       {
 421       case EMPTY:
 422          him[option] = NO;
 423          break;
 424
 425       case OPPOSITE:
 426          him[option] = WANTYES;
 427          himq[option] = EMPTY;
 428          send_negotiation(data, DO, option);
 429          break;
 430       }
 431       break;
 432
 433    case WANTYES:
 434       switch(himq[option])
 435       {
 436       case EMPTY:
 437          him[option] = NO;
 438          break;
 439       case OPPOSITE:
 440          him[option] = NO;
 441          himq[option] = EMPTY;
 442          break;
 443       }
 444       break;
 445    }
 446 }
 447
 448 void set_local_option(struct UrlData *data, int option, int newstate)
 449 {
 450    if(newstate == YES)
 451    {
 452       switch(us[option])
 453       {
 454       case NO:
 455          us[option] = WANTYES;
 456          send_negotiation(data, WILL, option);
 457          break;
 458
 459       case YES:
 460          /* Already enabled */
 461          break;
 462
 463       case WANTNO:
 464          switch(usq[option])
 465          {
 466          case EMPTY:
 467             /* Already negotiating for YES, queue the request */
 468             usq[option] = OPPOSITE;
 469             break;
 470          case OPPOSITE:
 471             /* Error: already queued an enable request */
 472             break;
 473          }
 474          break;
 475
 476       case WANTYES:
 477          switch(usq[option])
 478          {
 479          case EMPTY:
 480             /* Error: already negotiating for enable */
 481             break;
 482          case OPPOSITE:
 483             usq[option] = EMPTY;
 484             break;
 485          }
 486          break;
 487       }
 488    }
 489    else /* NO */
 490    {
 491       switch(us[option])
 492       {
 493       case NO:
 494          /* Already disabled */
 495          break;
 496
 497       case YES:
 498          us[option] = WANTNO;
 499          send_negotiation(data, WONT, option);
 500          break;
 501
 502       case WANTNO:
 503          switch(usq[option])
 504          {
 505          case EMPTY:
 506             /* Already negotiating for NO */
 507             break;
 508          case OPPOSITE:
 509             usq[option] = EMPTY;
 510             break;
 511          }
 512          break;
 513
 514       case WANTYES:
 515          switch(usq[option])
 516          {
 517          case EMPTY:
 518             usq[option] = OPPOSITE;
 519             break;
 520          case OPPOSITE:
 521             break;
 522          }
 523          break;
 524       }
 525    }
 526 }
 527
 528 void rec_do(struct UrlData *data, int option)
 529 {
 530    switch(us[option])
 531    {
 532    case NO:
 533       if(us_preferred[option] == YES)
 534       {
 535          us[option] = YES;
 536          send_negotiation(data, WILL, option);
 537       }
 538       else
 539       {
 540          send_negotiation(data, WONT, option);
 541       }
 542       break;
 543
 544    case YES:
 545       /* Already enabled */
 546       break;
 547
 548    case WANTNO:
 549       switch(usq[option])
 550       {
 551       case EMPTY:
 552          /* Error: DONT answered by WILL */
 553          us[option] = NO;
 554          break;
 555       case OPPOSITE:
 556          /* Error: DONT answered by WILL */
 557          us[option] = YES;
 558          usq[option] = EMPTY;
 559          break;
 560       }
 561       break;
 562
 563    case WANTYES:
 564       switch(usq[option])
 565       {
 566       case EMPTY:
 567          us[option] = YES;
 568          break;
 569       case OPPOSITE:
 570          us[option] = WANTNO;
 571          himq[option] = EMPTY;
 572          send_negotiation(data, WONT, option);
 573          break;
 574       }
 575       break;
 576    }
 577 }
 578
 579 void rec_dont(struct UrlData *data, int option)
 580 {
 581    switch(us[option])
 582    {
 583    case NO:
 584       /* Already disabled */
 585       break;
 586
 587    case YES:
 588       us[option] = NO;
 589       send_negotiation(data, WONT, option);
 590       break;
 591
 592    case WANTNO:
 593       switch(usq[option])
 594       {
 595       case EMPTY:
 596          us[option] = NO;
 597          break;
 598
 599       case OPPOSITE:
 600          us[option] = WANTYES;
 601          usq[option] = EMPTY;
 602          send_negotiation(data, WILL, option);
 603          break;
 604       }
 605       break;
 606
 607    case WANTYES:
 608       switch(usq[option])
 609       {
 610       case EMPTY:
 611          us[option] = NO;
 612          break;
 613       case OPPOSITE:
 614          us[option] = NO;
 615          usq[option] = EMPTY;
 616          break;
 617       }
 618       break;
 619    }
 620 }
 621
 622
 623 static void printsub(struct UrlData *data,
 624                      int direction,             /* '<' or '>' */
 625                      unsigned char *pointer,    /* where suboption data is */
 626                      int length)                /* length of suboption data */
 627
 628 {
 629    int i = 0;
 630
 631    if (data->conf & CONF_VERBOSE)
 632    {
 633       if (direction)
 634       {
 635          printf("%s IAC SB ", (direction == '<')? "RCVD":"SENT");
 636          if (length >= 3)
 637          {
 638             int j;
 639
 640             i = pointer[length-2];
 641             j = pointer[length-1];
 642
 643             if (i != IAC || j != SE)
 644             {
 645                printf("(terminated by ");
 646                if (TELOPT_OK(i))
 647                   printf("%s ", TELOPT(i));
 648                else if (TELCMD_OK(i))
 649                   printf("%s ", TELCMD(i));
 650                else
 651                   printf("%d ", i);
 652                if (TELOPT_OK(j))
 653                   printf("%s", TELOPT(j));
 654                else if (TELCMD_OK(j))
 655                   printf("%s", TELCMD(j));
 656                else
 657                   printf("%d", j);
 658                printf(", not IAC SE!) ");
 659             }
 660          }
 661          length -= 2;
 662       }
 663       if (length < 1)
 664       {
 665          printf("(Empty suboption?)");
 666          return;
 667       }
 668
 669       if (TELOPT_OK(pointer[0]))
 670          printf("%s (unknown)", TELOPT(pointer[0]));
 671       else
 672          printf("%d (unknown)", pointer[i]);
 673       for (i = 1; i < length; i++)
 674          printf(" %d", pointer[i]);
 675
 676       if (direction)
 677       {
 678          printf("\n");
 679       }
 680    }
 681 }
 682
 683 /*
 684  * suboption()
 685  *
 686  * Look at the sub-option buffer, and try to be helpful to the other
 687  * side.
 688  * No suboptions are supported yet.
 689  */
 690
 691 static void suboption(struct UrlData *data)
 692 {
 693    printsub(data, '<', (unsigned char *)subbuffer, SB_LEN()+2);
 694    return;
 695 }
 696
 697 void telrcv(struct UrlData *data,
 698             unsigned char *inbuf,       /* Data received from socket */
 699             int count)                  /* Number of bytes received */
 700 {
 701    unsigned char c;
 702    int index = 0;
 703
 704    while(count--)
 705    {
 706       c = inbuf[index++];
 707
 708       switch (telrcv_state)
 709       {
 710       case TS_CR:
 711          telrcv_state = TS_DATA;
 712          if (c == '\0')
 713          {
 714             break;   /* Ignore \0 after CR */
 715          }
 716
 717          data->fwrite((char *)&c, 1, 1, data->out);
 718          continue;
 719
 720       case TS_DATA:
 721          if (c == IAC)
 722          {
 723             telrcv_state = TS_IAC;
 724             break;
 725          }
 726          else if(c == '\r')
 727          {
 728             telrcv_state = TS_CR;
 729          }
 730
 731          data->fwrite((char *)&c, 1, 1, data->out);
 732          continue;
 733
 734       case TS_IAC:
 735         process_iac:
 736         switch (c)
 737         {
 738         case WILL:
 739            telrcv_state = TS_WILL;
 740            continue;
 741         case WONT:
 742            telrcv_state = TS_WONT;
 743            continue;
 744         case DO:
 745            telrcv_state = TS_DO;
 746            continue;
 747         case DONT:
 748            telrcv_state = TS_DONT;
 749            continue;
 750         case SB:
 751            SB_CLEAR();
 752            telrcv_state = TS_SB;
 753            continue;
 754         case IAC:
 755            data->fwrite((char *)&c, 1, 1, data->out);
 756            break;
 757         case DM:
 758         case NOP:
 759         case GA:
 760         default:
 761            printoption(data, "RCVD", IAC, c);
 762            break;
 763         }
 764         telrcv_state = TS_DATA;
 765         continue;
 766
 767       case TS_WILL:
 768          printoption(data, "RCVD", WILL, c);
 769          rec_will(data, c);
 770          telrcv_state = TS_DATA;
 771          continue;
 772
 773       case TS_WONT:
 774          printoption(data, "RCVD", WONT, c);
 775          rec_wont(data, c);
 776          telrcv_state = TS_DATA;
 777          continue;
 778
 779       case TS_DO:
 780          printoption(data, "RCVD", DO, c);
 781          rec_do(data, c);
 782          telrcv_state = TS_DATA;
 783          continue;
 784
 785       case TS_DONT:
 786          printoption(data, "RCVD", DONT, c);
 787          rec_dont(data, c);
 788          telrcv_state = TS_DATA;
 789          continue;
 790
 791       case TS_SB:
 792          if (c == IAC)
 793          {
 794             telrcv_state = TS_SE;
 795          }
 796          else
 797          {
 798             SB_ACCUM(c);
 799          }
 800          continue;
 801
 802       case TS_SE:
 803          if (c != SE)
 804          {
 805             if (c != IAC)
 806             {
 807                /*
 808                 * This is an error.  We only expect to get
 809                 * "IAC IAC" or "IAC SE".  Several things may
 810                 * have happend.  An IAC was not doubled, the
 811                 * IAC SE was left off, or another option got
 812                 * inserted into the suboption are all possibilities.
 813                 * If we assume that the IAC was not doubled,
 814                 * and really the IAC SE was left off, we could
 815                 * get into an infinate loop here.  So, instead,
 816                 * we terminate the suboption, and process the
 817                 * partial suboption if we can.
 818                 */
 819                SB_ACCUM((unsigned char)IAC);
 820                SB_ACCUM(c);
 821                subpointer -= 2;
 822                SB_TERM();
 823
 824                printoption(data, "In SUBOPTION processing, RCVD", IAC, c);
 825                suboption(data);   /* handle sub-option */
 826                telrcv_state = TS_IAC;
 827                goto process_iac;
 828             }
 829             SB_ACCUM(c);
 830             telrcv_state = TS_SB;
 831          }
 832          else
 833          {
 834             SB_ACCUM((unsigned char)IAC);
 835             SB_ACCUM((unsigned char)SE);
 836             subpointer -= 2;
 837             SB_TERM();
 838             suboption(data);   /* handle sub-option */
 839             telrcv_state = TS_DATA;
 840          }
 841          break;
 842       }
 843    }
 844 }
 845
 846 void telwrite(struct UrlData *data,
 847               unsigned char *buffer,    /* Data to write */
 848               int count)                /* Number of bytes to write */
 849 {
 850    unsigned char outbuf[2];
 851    int out_count = 0;
 852    int bytes_written;
 853
 854    while(count--)
 855    {
 856       outbuf[0] = *buffer++;
 857       out_count = 1;
 858       if(outbuf[0] == IAC)
 859          outbuf[out_count++] = IAC;
 860
 861 #ifndef USE_SSLEAY
 862       bytes_written = swrite(data->firstsocket, outbuf, out_count);
 863 #else
 864       if (data->use_ssl) {
 865         bytes_written = SSL_write(data->ssl, (char *)outbuf, out_count);
 866       }
 867       else {
 868         bytes_written = swrite(data->firstsocket, outbuf, out_count);
 869       }
 870 #endif /* USE_SSLEAY */
 871    }
 872 }
 873
 874 UrgError telnet(struct UrlData *data)
 875 {
 876    int sockfd = data->firstsocket;
 877    fd_set readfd;
 878    fd_set keepfd;
 879
 880    bool keepon = TRUE;
 881    char *buf = data->buffer;
 882    int nread;
 883
 884    init_telnet(data);
 885
 886    FD_ZERO (&readfd);           /* clear it */
 887    FD_SET (sockfd, &readfd);
 888    FD_SET (1, &readfd);
 889
 890    keepfd = readfd;
 891
 892    while (keepon)
 893    {
 894       readfd = keepfd;          /* set this every lap in the loop */
 895
 896       switch (select (sockfd + 1, &readfd, NULL, NULL, NULL))
 897       {
 898       case -1:                  /* error, stop reading */
 899          keepon = FALSE;
 900          continue;
 901       case 0:                   /* timeout */
 902          break;
 903       default:                  /* read! */
 904          if(FD_ISSET(1, &readfd))
 905          {
 906             nread = read(1, buf, 255);
 907             telwrite(data, (unsigned char *)buf, nread);
 908          }
 909
 910          if(FD_ISSET(sockfd, &readfd))
 911          {
 912 #ifndef USE_SSLEAY
 913             nread = sread (sockfd, buf, BUFSIZE - 1);
 914 #else
 915             if (data->use_ssl) {
 916                nread = SSL_read (data->ssl, buf, BUFSIZE - 1);
 917             }
 918             else {
 919                nread = sread (sockfd, buf, BUFSIZE - 1);
 920             }
 921 #endif /* USE_SSLEAY */
 922          }
 923
 924          /* if we receive 0 or less here, the server closed the connection and
 925            we bail out from this! */
 926         if (nread <= 0) {
 927           keepon = FALSE;
 928           break;
 929         }
 930
 931          telrcv(data, (unsigned char *)buf, nread);
 932       }
 933    }
 934    return URG_OK;
 935 }
 936
 937