libexec/telnetd/state.c

   1 /*
   2  * Copyright (c) 1989, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #ifndef lint
  35 #if 0
  36 static char sccsid[] = "@(#)state.c     8.2 (Berkeley) 12/15/93";
  37 #endif
  38 static const char rcsid[] =
  39         "$Id$";
  40 #endif /* not lint */
  41
  42 #include "telnetd.h"
  43 #if     defined(AUTHENTICATION)
  44 #include <libtelnet/auth.h>
  45 #endif
  46
  47 unsigned char   doopt[] = { IAC, DO, '%', 'c', 0 };
  48 unsigned char   dont[] = { IAC, DONT, '%', 'c', 0 };
  49 unsigned char   will[] = { IAC, WILL, '%', 'c', 0 };
  50 unsigned char   wont[] = { IAC, WONT, '%', 'c', 0 };
  51 int     not42 = 1;
  52
  53 /*
  54  * Buffer for sub-options, and macros
  55  * for suboptions buffer manipulations
  56  */
  57 unsigned char subbuffer[512], *subpointer= subbuffer, *subend= subbuffer;
  58
  59 #define SB_CLEAR()      subpointer = subbuffer
  60 #define SB_TERM()       { subend = subpointer; SB_CLEAR(); }
  61 #define SB_ACCUM(c)     if (subpointer < (subbuffer+sizeof subbuffer)) { \
  62                                 *subpointer++ = (c); \
  63                         }
  64 #define SB_GET()        ((*subpointer++)&0xff)
  65 #define SB_EOF()        (subpointer >= subend)
  66 #define SB_LEN()        (subend - subpointer)
  67
  68 #ifdef  ENV_HACK
  69 unsigned char *subsave;
  70 #define SB_SAVE()       subsave = subpointer;
  71 #define SB_RESTORE()    subpointer = subsave;
  72 #endif
  73
  74
  75 /*
  76  * State for recv fsm
  77  */
  78 #define TS_DATA         0       /* base state */
  79 #define TS_IAC          1       /* look for double IAC's */
  80 #define TS_CR           2       /* CR-LF ->'s CR */
  81 #define TS_SB           3       /* throw away begin's... */
  82 #define TS_SE           4       /* ...end's (suboption negotiation) */
  83 #define TS_WILL         5       /* will option negotiation */
  84 #define TS_WONT         6       /* wont " */
  85 #define TS_DO           7       /* do " */
  86 #define TS_DONT         8       /* dont " */
  87
  88         void
  89 telrcv()
  90 {
  91         register int c;
  92         static int state = TS_DATA;
  93 #if     defined(CRAY2) && defined(UNICOS5)
  94         char *opfrontp = pfrontp;
  95 #endif
  96
  97         while (ncc > 0) {
  98                 if ((&ptyobuf[BUFSIZ] - pfrontp) < 2)
  99                         break;
 100                 c = *netip++ & 0377, ncc--;
 101                 switch (state) {
 102
 103                 case TS_CR:
 104                         state = TS_DATA;
 105                         /* Strip off \n or \0 after a \r */
 106                         if ((c == 0) || (c == '\n')) {
 107                                 break;
 108                         }
 109                         /* FALL THROUGH */
 110
 111                 case TS_DATA:
 112                         if (c == IAC) {
 113                                 state = TS_IAC;
 114                                 break;
 115                         }
 116                         /*
 117                          * We now map \r\n ==> \r for pragmatic reasons.
 118                          * Many client implementations send \r\n when
 119                          * the user hits the CarriageReturn key.
 120                          *
 121                          * We USED to map \r\n ==> \n, since \r\n says
 122                          * that we want to be in column 1 of the next
 123                          * printable line, and \n is the standard
 124                          * unix way of saying that (\r is only good
 125                          * if CRMOD is set, which it normally is).
 126                          */
 127                         if ((c == '\r') && his_state_is_wont(TELOPT_BINARY)) {
 128                                 int nc = *netip;
 129 #ifdef  LINEMODE
 130                                 /*
 131                                  * If we are operating in linemode,
 132                                  * convert to local end-of-line.
 133                                  */
 134                                 if (linemode && (ncc > 0) && (('\n' == nc) ||
 135                                          ((0 == nc) && tty_iscrnl())) ) {
 136                                         netip++; ncc--;
 137                                         c = '\n';
 138                                 } else
 139 #endif
 140                                 {
 141                                         state = TS_CR;
 142                                 }
 143                         }
 144                         *pfrontp++ = c;
 145                         break;
 146
 147                 case TS_IAC:
 148 gotiac:                 switch (c) {
 149
 150                         /*
 151                          * Send the process on the pty side an
 152                          * interrupt.  Do this with a NULL or
 153                          * interrupt char; depending on the tty mode.
 154                          */
 155                         case IP:
 156                                 DIAG(TD_OPTIONS,
 157                                         printoption("td: recv IAC", c));
 158                                 interrupt();
 159                                 break;
 160
 161                         case BREAK:
 162                                 DIAG(TD_OPTIONS,
 163                                         printoption("td: recv IAC", c));
 164                                 sendbrk();
 165                                 break;
 166
 167                         /*
 168                          * Are You There?
 169                          */
 170                         case AYT:
 171                                 DIAG(TD_OPTIONS,
 172                                         printoption("td: recv IAC", c));
 173                                 recv_ayt();
 174                                 break;
 175
 176                         /*
 177                          * Abort Output
 178                          */
 179                         case AO:
 180                             {
 181                                 DIAG(TD_OPTIONS,
 182                                         printoption("td: recv IAC", c));
 183                                 ptyflush();     /* half-hearted */
 184                                 init_termbuf();
 185
 186                                 if (slctab[SLC_AO].sptr &&
 187                                     *slctab[SLC_AO].sptr != (cc_t)(_POSIX_VDISABLE)) {
 188                                     *pfrontp++ =
 189                                         (unsigned char)*slctab[SLC_AO].sptr;
 190                                 }
 191
 192                                 netclear();     /* clear buffer back */
 193                                 *nfrontp++ = IAC;
 194                                 *nfrontp++ = DM;
 195                                 neturg = nfrontp-1; /* off by one XXX */
 196                                 DIAG(TD_OPTIONS,
 197                                         printoption("td: send IAC", DM));
 198                                 break;
 199                             }
 200
 201                         /*
 202                          * Erase Character and
 203                          * Erase Line
 204                          */
 205                         case EC:
 206                         case EL:
 207                             {
 208                                 cc_t ch;
 209
 210                                 DIAG(TD_OPTIONS,
 211                                         printoption("td: recv IAC", c));
 212                                 ptyflush();     /* half-hearted */
 213                                 init_termbuf();
 214                                 if (c == EC)
 215                                         ch = *slctab[SLC_EC].sptr;
 216                                 else
 217                                         ch = *slctab[SLC_EL].sptr;
 218                                 if (ch != (cc_t)(_POSIX_VDISABLE))
 219                                         *pfrontp++ = (unsigned char)ch;
 220                                 break;
 221                             }
 222
 223                         /*
 224                          * Check for urgent data...
 225                          */
 226                         case DM:
 227                                 DIAG(TD_OPTIONS,
 228                                         printoption("td: recv IAC", c));
 229                                 SYNCHing = stilloob(net);
 230                                 settimer(gotDM);
 231                                 break;
 232
 233
 234                         /*
 235                          * Begin option subnegotiation...
 236                          */
 237                         case SB:
 238                                 state = TS_SB;
 239                                 SB_CLEAR();
 240                                 continue;
 241
 242                         case WILL:
 243                                 state = TS_WILL;
 244                                 continue;
 245
 246                         case WONT:
 247                                 state = TS_WONT;
 248                                 continue;
 249
 250                         case DO:
 251                                 state = TS_DO;
 252                                 continue;
 253
 254                         case DONT:
 255                                 state = TS_DONT;
 256                                 continue;
 257                         case EOR:
 258                                 if (his_state_is_will(TELOPT_EOR))
 259                                         doeof();
 260                                 break;
 261
 262                         /*
 263                          * Handle RFC 10xx Telnet linemode option additions
 264                          * to command stream (EOF, SUSP, ABORT).
 265                          */
 266                         case xEOF:
 267                                 doeof();
 268                                 break;
 269
 270                         case SUSP:
 271                                 sendsusp();
 272                                 break;
 273
 274                         case ABORT:
 275                                 sendbrk();
 276                                 break;
 277
 278                         case IAC:
 279                                 *pfrontp++ = c;
 280                                 break;
 281                         }
 282                         state = TS_DATA;
 283                         break;
 284
 285                 case TS_SB:
 286                         if (c == IAC) {
 287                                 state = TS_SE;
 288                         } else {
 289                                 SB_ACCUM(c);
 290                         }
 291                         break;
 292
 293                 case TS_SE:
 294                         if (c != SE) {
 295                                 if (c != IAC) {
 296                                         /*
 297                                          * bad form of suboption negotiation.
 298                                          * handle it in such a way as to avoid
 299                                          * damage to local state.  Parse
 300                                          * suboption buffer found so far,
 301                                          * then treat remaining stream as
 302                                          * another command sequence.
 303                                          */
 304
 305                                         /* for DIAGNOSTICS */
 306                                         SB_ACCUM(IAC);
 307                                         SB_ACCUM(c);
 308                                         subpointer -= 2;
 309
 310                                         SB_TERM();
 311                                         suboption();
 312                                         state = TS_IAC;
 313                                         goto gotiac;
 314                                 }
 315                                 SB_ACCUM(c);
 316                                 state = TS_SB;
 317                         } else {
 318                                 /* for DIAGNOSTICS */
 319                                 SB_ACCUM(IAC);
 320                                 SB_ACCUM(SE);
 321                                 subpointer -= 2;
 322
 323                                 SB_TERM();
 324                                 suboption();    /* handle sub-option */
 325                                 state = TS_DATA;
 326                         }
 327                         break;
 328
 329                 case TS_WILL:
 330                         willoption(c);
 331                         state = TS_DATA;
 332                         continue;
 333
 334                 case TS_WONT:
 335                         wontoption(c);
 336                         state = TS_DATA;
 337                         continue;
 338
 339                 case TS_DO:
 340                         dooption(c);
 341                         state = TS_DATA;
 342                         continue;
 343
 344                 case TS_DONT:
 345                         dontoption(c);
 346                         state = TS_DATA;
 347                         continue;
 348
 349                 default:
 350                         syslog(LOG_ERR, "panic state=%d", state);
 351                         printf("telnetd: panic state=%d\n", state);
 352                         exit(1);
 353                 }
 354         }
 355 #if     defined(CRAY2) && defined(UNICOS5)
 356         if (!linemode) {
 357                 char    xptyobuf[BUFSIZ+NETSLOP];
 358                 char    xbuf2[BUFSIZ];
 359                 register char *cp;
 360                 int n = pfrontp - opfrontp, oc;
 361                 bcopy(opfrontp, xptyobuf, n);
 362                 pfrontp = opfrontp;
 363                 pfrontp += term_input(xptyobuf, pfrontp, n, BUFSIZ+NETSLOP,
 364                                         xbuf2, &oc, BUFSIZ);
 365                 for (cp = xbuf2; oc > 0; --oc)
 366                         if ((*nfrontp++ = *cp++) == IAC)
 367                                 *nfrontp++ = IAC;
 368         }
 369 #endif  /* defined(CRAY2) && defined(UNICOS5) */
 370 }  /* end of telrcv */
 371
 372 /*
 373  * The will/wont/do/dont state machines are based on Dave Borman's
 374  * Telnet option processing state machine.
 375  *
 376  * These correspond to the following states:
 377  *      my_state = the last negotiated state
 378  *      want_state = what I want the state to go to
 379  *      want_resp = how many requests I have sent
 380  * All state defaults are negative, and resp defaults to 0.
 381  *
 382  * When initiating a request to change state to new_state:
 383  *
 384  * if ((want_resp == 0 && new_state == my_state) || want_state == new_state) {
 385  *      do nothing;
 386  * } else {
 387  *      want_state = new_state;
 388  *      send new_state;
 389  *      want_resp++;
 390  * }
 391  *
 392  * When receiving new_state:
 393  *
 394  * if (want_resp) {
 395  *      want_resp--;
 396  *      if (want_resp && (new_state == my_state))
 397  *              want_resp--;
 398  * }
 399  * if ((want_resp == 0) && (new_state != want_state)) {
 400  *      if (ok_to_switch_to new_state)
 401  *              want_state = new_state;
 402  *      else
 403  *              want_resp++;
 404  *      send want_state;
 405  * }
 406  * my_state = new_state;
 407  *
 408  * Note that new_state is implied in these functions by the function itself.
 409  * will and do imply positive new_state, wont and dont imply negative.
 410  *
 411  * Finally, there is one catch.  If we send a negative response to a
 412  * positive request, my_state will be the positive while want_state will
 413  * remain negative.  my_state will revert to negative when the negative
 414  * acknowlegment arrives from the peer.  Thus, my_state generally tells
 415  * us not only the last negotiated state, but also tells us what the peer
 416  * wants to be doing as well.  It is important to understand this difference
 417  * as we may wish to be processing data streams based on our desired state
 418  * (want_state) or based on what the peer thinks the state is (my_state).
 419  *
 420  * This all works fine because if the peer sends a positive request, the data
 421  * that we receive prior to negative acknowlegment will probably be affected
 422  * by the positive state, and we can process it as such (if we can; if we
 423  * can't then it really doesn't matter).  If it is that important, then the
 424  * peer probably should be buffering until this option state negotiation
 425  * is complete.
 426  *
 427  */
 428         void
 429 send_do(option, init)
 430         int option, init;
 431 {
 432         if (init) {
 433                 if ((do_dont_resp[option] == 0 && his_state_is_will(option)) ||
 434                     his_want_state_is_will(option))
 435                         return;
 436                 /*
 437                  * Special case for TELOPT_TM:  We send a DO, but pretend
 438                  * that we sent a DONT, so that we can send more DOs if
 439                  * we want to.
 440                  */
 441                 if (option == TELOPT_TM)
 442                         set_his_want_state_wont(option);
 443                 else
 444                         set_his_want_state_will(option);
 445                 do_dont_resp[option]++;
 446         }
 447         (void) sprintf(nfrontp, (char *)doopt, option);
 448         nfrontp += sizeof (dont) - 2;
 449
 450         DIAG(TD_OPTIONS, printoption("td: send do", option));
 451 }
 452
 453 #ifdef  AUTHENTICATION
 454 extern void auth_request();
 455 #endif
 456 #ifdef  LINEMODE
 457 extern void doclientstat();
 458 #endif
 459
 460         void
 461 willoption(option)
 462         int option;
 463 {
 464         int changeok = 0;
 465         void (*func)() = 0;
 466
 467         /*
 468          * process input from peer.
 469          */
 470
 471         DIAG(TD_OPTIONS, printoption("td: recv will", option));
 472
 473         if (do_dont_resp[option]) {
 474                 do_dont_resp[option]--;
 475                 if (do_dont_resp[option] && his_state_is_will(option))
 476                         do_dont_resp[option]--;
 477         }
 478         if (do_dont_resp[option] == 0) {
 479             if (his_want_state_is_wont(option)) {
 480                 switch (option) {
 481
 482                 case TELOPT_BINARY:
 483                         init_termbuf();
 484                         tty_binaryin(1);
 485                         set_termbuf();
 486                         changeok++;
 487                         break;
 488
 489                 case TELOPT_ECHO:
 490                         /*
 491                          * See comments below for more info.
 492                          */
 493                         not42 = 0;      /* looks like a 4.2 system */
 494                         break;
 495
 496                 case TELOPT_TM:
 497 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
 498                         /*
 499                          * This telnetd implementation does not really
 500                          * support timing marks, it just uses them to
 501                          * support the kludge linemode stuff.  If we
 502                          * receive a will or wont TM in response to our
 503                          * do TM request that may have been sent to
 504                          * determine kludge linemode support, process
 505                          * it, otherwise TM should get a negative
 506                          * response back.
 507                          */
 508                         /*
 509                          * Handle the linemode kludge stuff.
 510                          * If we are not currently supporting any
 511                          * linemode at all, then we assume that this
 512                          * is the client telling us to use kludge
 513                          * linemode in response to our query.  Set the
 514                          * linemode type that is to be supported, note
 515                          * that the client wishes to use linemode, and
 516                          * eat the will TM as though it never arrived.
 517                          */
 518                         if (lmodetype < KLUDGE_LINEMODE) {
 519                                 lmodetype = KLUDGE_LINEMODE;
 520                                 clientstat(TELOPT_LINEMODE, WILL, 0);
 521                                 send_wont(TELOPT_SGA, 1);
 522                         } else if (lmodetype == NO_AUTOKLUDGE) {
 523                                 lmodetype = KLUDGE_OK;
 524                         }
 525 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
 526                         /*
 527                          * We never respond to a WILL TM, and
 528                          * we leave the state WONT.
 529                          */
 530                         return;
 531
 532                 case TELOPT_LFLOW:
 533                         /*
 534                          * If we are going to support flow control
 535                          * option, then don't worry peer that we can't
 536                          * change the flow control characters.
 537                          */
 538                         slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
 539                         slctab[SLC_XON].defset.flag |= SLC_DEFAULT;
 540                         slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
 541                         slctab[SLC_XOFF].defset.flag |= SLC_DEFAULT;
 542                 case TELOPT_TTYPE:
 543                 case TELOPT_SGA:
 544                 case TELOPT_NAWS:
 545                 case TELOPT_TSPEED:
 546                 case TELOPT_XDISPLOC:
 547                 case TELOPT_NEW_ENVIRON:
 548                 case TELOPT_OLD_ENVIRON:
 549                         changeok++;
 550                         break;
 551
 552 #ifdef  LINEMODE
 553                 case TELOPT_LINEMODE:
 554 # ifdef KLUDGELINEMODE
 555                         /*
 556                          * Note client's desire to use linemode.
 557                          */
 558                         lmodetype = REAL_LINEMODE;
 559 # endif /* KLUDGELINEMODE */
 560                         func = doclientstat;
 561                         changeok++;
 562                         break;
 563 #endif  /* LINEMODE */
 564
 565 #ifdef  AUTHENTICATION
 566                 case TELOPT_AUTHENTICATION:
 567                         func = auth_request;
 568                         changeok++;
 569                         break;
 570 #endif
 571
 572
 573                 default:
 574                         break;
 575                 }
 576                 if (changeok) {
 577                         set_his_want_state_will(option);
 578                         send_do(option, 0);
 579                 } else {
 580                         do_dont_resp[option]++;
 581                         send_dont(option, 0);
 582                 }
 583             } else {
 584                 /*
 585                  * Option processing that should happen when
 586                  * we receive conformation of a change in
 587                  * state that we had requested.
 588                  */
 589                 switch (option) {
 590                 case TELOPT_ECHO:
 591                         not42 = 0;      /* looks like a 4.2 system */
 592                         /*
 593                          * Egads, he responded "WILL ECHO".  Turn
 594                          * it off right now!
 595                          */
 596                         send_dont(option, 1);
 597                         /*
 598                          * "WILL ECHO".  Kludge upon kludge!
 599                          * A 4.2 client is now echoing user input at
 600                          * the tty.  This is probably undesireable and
 601                          * it should be stopped.  The client will
 602                          * respond WONT TM to the DO TM that we send to
 603                          * check for kludge linemode.  When the WONT TM
 604                          * arrives, linemode will be turned off and a
 605                          * change propogated to the pty.  This change
 606                          * will cause us to process the new pty state
 607                          * in localstat(), which will notice that
 608                          * linemode is off and send a WILL ECHO
 609                          * so that we are properly in character mode and
 610                          * all is well.
 611                          */
 612                         break;
 613 #ifdef  LINEMODE
 614                 case TELOPT_LINEMODE:
 615 # ifdef KLUDGELINEMODE
 616                         /*
 617                          * Note client's desire to use linemode.
 618                          */
 619                         lmodetype = REAL_LINEMODE;
 620 # endif /* KLUDGELINEMODE */
 621                         func = doclientstat;
 622                         break;
 623 #endif  /* LINEMODE */
 624
 625 #ifdef  AUTHENTICATION
 626                 case TELOPT_AUTHENTICATION:
 627                         func = auth_request;
 628                         break;
 629 #endif
 630
 631                 case TELOPT_LFLOW:
 632                         func = flowstat;
 633                         break;
 634                 }
 635             }
 636         }
 637         set_his_state_will(option);
 638         if (func)
 639                 (*func)();
 640 }  /* end of willoption */
 641
 642         void
 643 send_dont(option, init)
 644         int option, init;
 645 {
 646         if (init) {
 647                 if ((do_dont_resp[option] == 0 && his_state_is_wont(option)) ||
 648                     his_want_state_is_wont(option))
 649                         return;
 650                 set_his_want_state_wont(option);
 651                 do_dont_resp[option]++;
 652         }
 653         (void) sprintf(nfrontp, (char *)dont, option);
 654         nfrontp += sizeof (doopt) - 2;
 655
 656         DIAG(TD_OPTIONS, printoption("td: send dont", option));
 657 }
 658
 659         void
 660 wontoption(option)
 661         int option;
 662 {
 663         /*
 664          * Process client input.
 665          */
 666
 667         DIAG(TD_OPTIONS, printoption("td: recv wont", option));
 668
 669         if (do_dont_resp[option]) {
 670                 do_dont_resp[option]--;
 671                 if (do_dont_resp[option] && his_state_is_wont(option))
 672                         do_dont_resp[option]--;
 673         }
 674         if (do_dont_resp[option] == 0) {
 675             if (his_want_state_is_will(option)) {
 676                 /* it is always ok to change to negative state */
 677                 switch (option) {
 678                 case TELOPT_ECHO:
 679                         not42 = 1; /* doesn't seem to be a 4.2 system */
 680                         break;
 681
 682                 case TELOPT_BINARY:
 683                         init_termbuf();
 684                         tty_binaryin(0);
 685                         set_termbuf();
 686                         break;
 687
 688 #ifdef  LINEMODE
 689                 case TELOPT_LINEMODE:
 690 # ifdef KLUDGELINEMODE
 691                         /*
 692                          * If real linemode is supported, then client is
 693                          * asking to turn linemode off.
 694                          */
 695                         if (lmodetype != REAL_LINEMODE)
 696                                 break;
 697                         lmodetype = KLUDGE_LINEMODE;
 698 # endif /* KLUDGELINEMODE */
 699                         clientstat(TELOPT_LINEMODE, WONT, 0);
 700                         break;
 701 #endif  /* LINEMODE */
 702
 703                 case TELOPT_TM:
 704                         /*
 705                          * If we get a WONT TM, and had sent a DO TM,
 706                          * don't respond with a DONT TM, just leave it
 707                          * as is.  Short circut the state machine to
 708                          * achive this.
 709                          */
 710                         set_his_want_state_wont(TELOPT_TM);
 711                         return;
 712
 713                 case TELOPT_LFLOW:
 714                         /*
 715                          * If we are not going to support flow control
 716                          * option, then let peer know that we can't
 717                          * change the flow control characters.
 718                          */
 719                         slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
 720                         slctab[SLC_XON].defset.flag |= SLC_CANTCHANGE;
 721                         slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
 722                         slctab[SLC_XOFF].defset.flag |= SLC_CANTCHANGE;
 723                         break;
 724
 725 #if     defined(AUTHENTICATION)
 726                 case TELOPT_AUTHENTICATION:
 727                         auth_finished(0, AUTH_REJECT);
 728                         break;
 729 #endif
 730
 731                 /*
 732                  * For options that we might spin waiting for
 733                  * sub-negotiation, if the client turns off the
 734                  * option rather than responding to the request,
 735                  * we have to treat it here as if we got a response
 736                  * to the sub-negotiation, (by updating the timers)
 737                  * so that we'll break out of the loop.
 738                  */
 739                 case TELOPT_TTYPE:
 740                         settimer(ttypesubopt);
 741                         break;
 742
 743                 case TELOPT_TSPEED:
 744                         settimer(tspeedsubopt);
 745                         break;
 746
 747                 case TELOPT_XDISPLOC:
 748                         settimer(xdisplocsubopt);
 749                         break;
 750
 751                 case TELOPT_OLD_ENVIRON:
 752                         settimer(oenvironsubopt);
 753                         break;
 754
 755                 case TELOPT_NEW_ENVIRON:
 756                         settimer(environsubopt);
 757                         break;
 758
 759                 default:
 760                         break;
 761                 }
 762                 set_his_want_state_wont(option);
 763                 if (his_state_is_will(option))
 764                         send_dont(option, 0);
 765             } else {
 766                 switch (option) {
 767                 case TELOPT_TM:
 768 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
 769                         if (lmodetype < NO_AUTOKLUDGE) {
 770                                 lmodetype = NO_LINEMODE;
 771                                 clientstat(TELOPT_LINEMODE, WONT, 0);
 772                                 send_will(TELOPT_SGA, 1);
 773                                 send_will(TELOPT_ECHO, 1);
 774                         }
 775 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
 776                         break;
 777
 778 #if     defined(AUTHENTICATION)
 779                 case TELOPT_AUTHENTICATION:
 780                         auth_finished(0, AUTH_REJECT);
 781                         break;
 782 #endif
 783                 default:
 784                         break;
 785                 }
 786             }
 787         }
 788         set_his_state_wont(option);
 789
 790 }  /* end of wontoption */
 791
 792         void
 793 send_will(option, init)
 794         int option, init;
 795 {
 796         if (init) {
 797                 if ((will_wont_resp[option] == 0 && my_state_is_will(option))||
 798                     my_want_state_is_will(option))
 799                         return;
 800                 set_my_want_state_will(option);
 801                 will_wont_resp[option]++;
 802         }
 803         (void) sprintf(nfrontp, (char *)will, option);
 804         nfrontp += sizeof (doopt) - 2;
 805
 806         DIAG(TD_OPTIONS, printoption("td: send will", option));
 807 }
 808
 809 #if     !defined(LINEMODE) || !defined(KLUDGELINEMODE)
 810 /*
 811  * When we get a DONT SGA, we will try once to turn it
 812  * back on.  If the other side responds DONT SGA, we
 813  * leave it at that.  This is so that when we talk to
 814  * clients that understand KLUDGELINEMODE but not LINEMODE,
 815  * we'll keep them in char-at-a-time mode.
 816  */
 817 int turn_on_sga = 0;
 818 #endif
 819
 820         void
 821 dooption(option)
 822         int option;
 823 {
 824         int changeok = 0;
 825
 826         /*
 827          * Process client input.
 828          */
 829
 830         DIAG(TD_OPTIONS, printoption("td: recv do", option));
 831
 832         if (will_wont_resp[option]) {
 833                 will_wont_resp[option]--;
 834                 if (will_wont_resp[option] && my_state_is_will(option))
 835                         will_wont_resp[option]--;
 836         }
 837         if ((will_wont_resp[option] == 0) && (my_want_state_is_wont(option))) {
 838                 switch (option) {
 839                 case TELOPT_ECHO:
 840 #ifdef  LINEMODE
 841 # ifdef KLUDGELINEMODE
 842                         if (lmodetype == NO_LINEMODE)
 843 # else
 844                         if (his_state_is_wont(TELOPT_LINEMODE))
 845 # endif
 846 #endif
 847                         {
 848                                 init_termbuf();
 849                                 tty_setecho(1);
 850                                 set_termbuf();
 851                         }
 852                         changeok++;
 853                         break;
 854
 855                 case TELOPT_BINARY:
 856                         init_termbuf();
 857                         tty_binaryout(1);
 858                         set_termbuf();
 859                         changeok++;
 860                         break;
 861
 862                 case TELOPT_SGA:
 863 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
 864                         /*
 865                          * If kludge linemode is in use, then we must
 866                          * process an incoming do SGA for linemode
 867                          * purposes.
 868                          */
 869                         if (lmodetype == KLUDGE_LINEMODE) {
 870                                 /*
 871                                  * Receipt of "do SGA" in kludge
 872                                  * linemode is the peer asking us to
 873                                  * turn off linemode.  Make note of
 874                                  * the request.
 875                                  */
 876                                 clientstat(TELOPT_LINEMODE, WONT, 0);
 877                                 /*
 878                                  * If linemode did not get turned off
 879                                  * then don't tell peer that we did.
 880                                  * Breaking here forces a wont SGA to
 881                                  * be returned.
 882                                  */
 883                                 if (linemode)
 884                                         break;
 885                         }
 886 #else
 887                         turn_on_sga = 0;
 888 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
 889                         changeok++;
 890                         break;
 891
 892                 case TELOPT_STATUS:
 893                         changeok++;
 894                         break;
 895
 896                 case TELOPT_TM:
 897                         /*
 898                          * Special case for TM.  We send a WILL, but
 899                          * pretend we sent a WONT.
 900                          */
 901                         send_will(option, 0);
 902                         set_my_want_state_wont(option);
 903                         set_my_state_wont(option);
 904                         return;
 905
 906                 case TELOPT_LOGOUT:
 907                         /*
 908                          * When we get a LOGOUT option, respond
 909                          * with a WILL LOGOUT, make sure that
 910                          * it gets written out to the network,
 911                          * and then just go away...
 912                          */
 913                         set_my_want_state_will(TELOPT_LOGOUT);
 914                         send_will(TELOPT_LOGOUT, 0);
 915                         set_my_state_will(TELOPT_LOGOUT);
 916                         (void)netflush();
 917                         cleanup(0);
 918                         /* NOT REACHED */
 919                         break;
 920
 921                 case TELOPT_LINEMODE:
 922                 case TELOPT_TTYPE:
 923                 case TELOPT_NAWS:
 924                 case TELOPT_TSPEED:
 925                 case TELOPT_LFLOW:
 926                 case TELOPT_XDISPLOC:
 927 #ifdef  TELOPT_ENVIRON
 928                 case TELOPT_NEW_ENVIRON:
 929 #endif
 930                 case TELOPT_OLD_ENVIRON:
 931                 default:
 932                         break;
 933                 }
 934                 if (changeok) {
 935                         set_my_want_state_will(option);
 936                         send_will(option, 0);
 937                 } else {
 938                         will_wont_resp[option]++;
 939                         send_wont(option, 0);
 940                 }
 941         }
 942         set_my_state_will(option);
 943
 944 }  /* end of dooption */
 945
 946         void
 947 send_wont(option, init)
 948         int option, init;
 949 {
 950         if (init) {
 951                 if ((will_wont_resp[option] == 0 && my_state_is_wont(option)) ||
 952                     my_want_state_is_wont(option))
 953                         return;
 954                 set_my_want_state_wont(option);
 955                 will_wont_resp[option]++;
 956         }
 957         (void) sprintf(nfrontp, (char *)wont, option);
 958         nfrontp += sizeof (wont) - 2;
 959
 960         DIAG(TD_OPTIONS, printoption("td: send wont", option));
 961 }
 962
 963         void
 964 dontoption(option)
 965         int option;
 966 {
 967         /*
 968          * Process client input.
 969          */
 970
 971
 972         DIAG(TD_OPTIONS, printoption("td: recv dont", option));
 973
 974         if (will_wont_resp[option]) {
 975                 will_wont_resp[option]--;
 976                 if (will_wont_resp[option] && my_state_is_wont(option))
 977                         will_wont_resp[option]--;
 978         }
 979         if ((will_wont_resp[option] == 0) && (my_want_state_is_will(option))) {
 980                 switch (option) {
 981                 case TELOPT_BINARY:
 982                         init_termbuf();
 983                         tty_binaryout(0);
 984                         set_termbuf();
 985                         break;
 986
 987                 case TELOPT_ECHO:       /* we should stop echoing */
 988 #ifdef  LINEMODE
 989 # ifdef KLUDGELINEMODE
 990                         if ((lmodetype != REAL_LINEMODE) &&
 991                             (lmodetype != KLUDGE_LINEMODE))
 992 # else
 993                         if (his_state_is_wont(TELOPT_LINEMODE))
 994 # endif
 995 #endif
 996                         {
 997                                 init_termbuf();
 998                                 tty_setecho(0);
 999                                 set_termbuf();
1000                         }
1001                         break;
1002
1003                 case TELOPT_SGA:
1004 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
1005                         /*
1006                          * If kludge linemode is in use, then we
1007                          * must process an incoming do SGA for
1008                          * linemode purposes.
1009                          */
1010                         if ((lmodetype == KLUDGE_LINEMODE) ||
1011                             (lmodetype == KLUDGE_OK)) {
1012                                 /*
1013                                  * The client is asking us to turn
1014                                  * linemode on.
1015                                  */
1016                                 lmodetype = KLUDGE_LINEMODE;
1017                                 clientstat(TELOPT_LINEMODE, WILL, 0);
1018                                 /*
1019                                  * If we did not turn line mode on,
1020                                  * then what do we say?  Will SGA?
1021                                  * This violates design of telnet.
1022                                  * Gross.  Very Gross.
1023                                  */
1024                         }
1025                         break;
1026 #else
1027                         set_my_want_state_wont(option);
1028                         if (my_state_is_will(option))
1029                                 send_wont(option, 0);
1030                         set_my_state_wont(option);
1031                         if (turn_on_sga ^= 1)
1032                                 send_will(option, 1);
1033                         return;
1034 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
1035
1036                 default:
1037                         break;
1038                 }
1039
1040                 set_my_want_state_wont(option);
1041                 if (my_state_is_will(option))
1042                         send_wont(option, 0);
1043         }
1044         set_my_state_wont(option);
1045
1046 }  /* end of dontoption */
1047
1048 #ifdef  ENV_HACK
1049 int env_ovar = -1;
1050 int env_ovalue = -1;
1051 #else   /* ENV_HACK */
1052 # define env_ovar OLD_ENV_VAR
1053 # define env_ovalue OLD_ENV_VALUE
1054 #endif  /* ENV_HACK */
1055
1056 /*
1057  * suboption()
1058  *
1059  *      Look at the sub-option buffer, and try to be helpful to the other
1060  * side.
1061  *
1062  *      Currently we recognize:
1063  *
1064  *      Terminal type is
1065  *      Linemode
1066  *      Window size
1067  *      Terminal speed
1068  */
1069         void
1070 suboption()
1071 {
1072     register int subchar;
1073
1074     DIAG(TD_OPTIONS, {netflush(); printsub('<', subpointer, SB_LEN()+2);});
1075
1076     subchar = SB_GET();
1077     switch (subchar) {
1078     case TELOPT_TSPEED: {
1079         register int xspeed, rspeed;
1080
1081         if (his_state_is_wont(TELOPT_TSPEED))   /* Ignore if option disabled */
1082                 break;
1083
1084         settimer(tspeedsubopt);
1085
1086         if (SB_EOF() || SB_GET() != TELQUAL_IS)
1087                 return;
1088
1089         xspeed = atoi((char *)subpointer);
1090
1091         while (SB_GET() != ',' && !SB_EOF());
1092         if (SB_EOF())
1093                 return;
1094
1095         rspeed = atoi((char *)subpointer);
1096         clientstat(TELOPT_TSPEED, xspeed, rspeed);
1097
1098         break;
1099
1100     }  /* end of case TELOPT_TSPEED */
1101
1102     case TELOPT_TTYPE: {                /* Yaaaay! */
1103         static char terminalname[41];
1104
1105         if (his_state_is_wont(TELOPT_TTYPE))    /* Ignore if option disabled */
1106                 break;
1107         settimer(ttypesubopt);
1108
1109         if (SB_EOF() || SB_GET() != TELQUAL_IS) {
1110             return;             /* ??? XXX but, this is the most robust */
1111         }
1112
1113         terminaltype = terminalname;
1114
1115         while ((terminaltype < (terminalname + sizeof terminalname-1)) &&
1116                                                                     !SB_EOF()) {
1117             register int c;
1118
1119             c = SB_GET();
1120             if (isupper(c)) {
1121                 c = tolower(c);
1122             }
1123             *terminaltype++ = c;    /* accumulate name */
1124         }
1125         *terminaltype = 0;
1126         terminaltype = terminalname;
1127         break;
1128     }  /* end of case TELOPT_TTYPE */
1129
1130     case TELOPT_NAWS: {
1131         register int xwinsize, ywinsize;
1132
1133         if (his_state_is_wont(TELOPT_NAWS))     /* Ignore if option disabled */
1134                 break;
1135
1136         if (SB_EOF())
1137                 return;
1138         xwinsize = SB_GET() << 8;
1139         if (SB_EOF())
1140                 return;
1141         xwinsize |= SB_GET();
1142         if (SB_EOF())
1143                 return;
1144         ywinsize = SB_GET() << 8;
1145         if (SB_EOF())
1146                 return;
1147         ywinsize |= SB_GET();
1148         clientstat(TELOPT_NAWS, xwinsize, ywinsize);
1149
1150         break;
1151
1152     }  /* end of case TELOPT_NAWS */
1153
1154 #ifdef  LINEMODE
1155     case TELOPT_LINEMODE: {
1156         register int request;
1157
1158         if (his_state_is_wont(TELOPT_LINEMODE)) /* Ignore if option disabled */
1159                 break;
1160         /*
1161          * Process linemode suboptions.
1162          */
1163         if (SB_EOF())
1164             break;              /* garbage was sent */
1165         request = SB_GET();     /* get will/wont */
1166
1167         if (SB_EOF())
1168             break;              /* another garbage check */
1169
1170         if (request == LM_SLC) {  /* SLC is not preceeded by WILL or WONT */
1171                 /*
1172                  * Process suboption buffer of slc's
1173                  */
1174                 start_slc(1);
1175                 do_opt_slc(subpointer, subend - subpointer);
1176                 (void) end_slc(0);
1177                 break;
1178         } else if (request == LM_MODE) {
1179                 if (SB_EOF())
1180                     return;
1181                 useeditmode = SB_GET();  /* get mode flag */
1182                 clientstat(LM_MODE, 0, 0);
1183                 break;
1184         }
1185
1186         if (SB_EOF())
1187             break;
1188         switch (SB_GET()) {  /* what suboption? */
1189         case LM_FORWARDMASK:
1190                 /*
1191                  * According to spec, only server can send request for
1192                  * forwardmask, and client can only return a positive response.
1193                  * So don't worry about it.
1194                  */
1195
1196         default:
1197                 break;
1198         }
1199         break;
1200     }  /* end of case TELOPT_LINEMODE */
1201 #endif
1202     case TELOPT_STATUS: {
1203         int mode;
1204
1205         if (SB_EOF())
1206             break;
1207         mode = SB_GET();
1208         switch (mode) {
1209         case TELQUAL_SEND:
1210             if (my_state_is_will(TELOPT_STATUS))
1211                 send_status();
1212             break;
1213
1214         case TELQUAL_IS:
1215             break;
1216
1217         default:
1218             break;
1219         }
1220         break;
1221     }  /* end of case TELOPT_STATUS */
1222
1223     case TELOPT_XDISPLOC: {
1224         if (SB_EOF() || SB_GET() != TELQUAL_IS)
1225                 return;
1226         settimer(xdisplocsubopt);
1227         subpointer[SB_LEN()] = '\0';
1228         (void)setenv("DISPLAY", (char *)subpointer, 1);
1229         break;
1230     }  /* end of case TELOPT_XDISPLOC */
1231
1232 #ifdef  TELOPT_NEW_ENVIRON
1233     case TELOPT_NEW_ENVIRON:
1234 #endif
1235     case TELOPT_OLD_ENVIRON: {
1236         register int c;
1237         register char *cp, *varp, *valp;
1238
1239         if (SB_EOF())
1240                 return;
1241         c = SB_GET();
1242         if (c == TELQUAL_IS) {
1243                 if (subchar == TELOPT_OLD_ENVIRON)
1244                         settimer(oenvironsubopt);
1245                 else
1246                         settimer(environsubopt);
1247         } else if (c != TELQUAL_INFO) {
1248                 return;
1249         }
1250
1251 #ifdef  TELOPT_NEW_ENVIRON
1252         if (subchar == TELOPT_NEW_ENVIRON) {
1253             while (!SB_EOF()) {
1254                 c = SB_GET();
1255                 if ((c == NEW_ENV_VAR) || (c == ENV_USERVAR))
1256                         break;
1257             }
1258         } else
1259 #endif
1260         {
1261 #ifdef  ENV_HACK
1262             /*
1263              * We only want to do this if we haven't already decided
1264              * whether or not the other side has its VALUE and VAR
1265              * reversed.
1266              */
1267             if (env_ovar < 0) {
1268                 register int last = -1;         /* invalid value */
1269                 int empty = 0;
1270                 int got_var = 0, got_value = 0, got_uservar = 0;
1271
1272                 /*
1273                  * The other side might have its VALUE and VAR values
1274                  * reversed.  To be interoperable, we need to determine
1275                  * which way it is.  If the first recognized character
1276                  * is a VAR or VALUE, then that will tell us what
1277                  * type of client it is.  If the fist recognized
1278                  * character is a USERVAR, then we continue scanning
1279                  * the suboption looking for two consecutive
1280                  * VAR or VALUE fields.  We should not get two
1281                  * consecutive VALUE fields, so finding two
1282                  * consecutive VALUE or VAR fields will tell us
1283                  * what the client is.
1284                  */
1285                 SB_SAVE();
1286                 while (!SB_EOF()) {
1287                         c = SB_GET();
1288                         switch(c) {
1289                         case OLD_ENV_VAR:
1290                                 if (last < 0 || last == OLD_ENV_VAR
1291                                     || (empty && (last == OLD_ENV_VALUE)))
1292                                         goto env_ovar_ok;
1293                                 got_var++;
1294                                 last = OLD_ENV_VAR;
1295                                 break;
1296                         case OLD_ENV_VALUE:
1297                                 if (last < 0 || last == OLD_ENV_VALUE
1298                                     || (empty && (last == OLD_ENV_VAR)))
1299                                         goto env_ovar_wrong;
1300                                 got_value++;
1301                                 last = OLD_ENV_VALUE;
1302                                 break;
1303                         case ENV_USERVAR:
1304                                 /* count strings of USERVAR as one */
1305                                 if (last != ENV_USERVAR)
1306                                         got_uservar++;
1307                                 if (empty) {
1308                                         if (last == OLD_ENV_VALUE)
1309                                                 goto env_ovar_ok;
1310                                         if (last == OLD_ENV_VAR)
1311                                                 goto env_ovar_wrong;
1312                                 }
1313                                 last = ENV_USERVAR;
1314                                 break;
1315                         case ENV_ESC:
1316                                 if (!SB_EOF())
1317                                         c = SB_GET();
1318                                 /* FALL THROUGH */
1319                         default:
1320                                 empty = 0;
1321                                 continue;
1322                         }
1323                         empty = 1;
1324                 }
1325                 if (empty) {
1326                         if (last == OLD_ENV_VALUE)
1327                                 goto env_ovar_ok;
1328                         if (last == OLD_ENV_VAR)
1329                                 goto env_ovar_wrong;
1330                 }
1331                 /*
1332                  * Ok, the first thing was a USERVAR, and there
1333                  * are not two consecutive VAR or VALUE commands,
1334                  * and none of the VAR or VALUE commands are empty.
1335                  * If the client has sent us a well-formed option,
1336                  * then the number of VALUEs received should always
1337                  * be less than or equal to the number of VARs and
1338                  * USERVARs received.
1339                  *
1340                  * If we got exactly as many VALUEs as VARs and
1341                  * USERVARs, the client has the same definitions.
1342                  *
1343                  * If we got exactly as many VARs as VALUEs and
1344                  * USERVARS, the client has reversed definitions.
1345                  */
1346                 if (got_uservar + got_var == got_value) {
1347             env_ovar_ok:
1348                         env_ovar = OLD_ENV_VAR;
1349                         env_ovalue = OLD_ENV_VALUE;
1350                 } else if (got_uservar + got_value == got_var) {
1351             env_ovar_wrong:
1352                         env_ovar = OLD_ENV_VALUE;
1353                         env_ovalue = OLD_ENV_VAR;
1354                         DIAG(TD_OPTIONS, {sprintf(nfrontp,
1355                                 "ENVIRON VALUE and VAR are reversed!\r\n");
1356                                 nfrontp += strlen(nfrontp);});
1357
1358                 }
1359             }
1360             SB_RESTORE();
1361 #endif
1362
1363             while (!SB_EOF()) {
1364                 c = SB_GET();
1365                 if ((c == env_ovar) || (c == ENV_USERVAR))
1366                         break;
1367             }
1368         }
1369
1370         if (SB_EOF())
1371                 return;
1372
1373         cp = varp = (char *)subpointer;
1374         valp = 0;
1375
1376         while (!SB_EOF()) {
1377                 c = SB_GET();
1378                 if (subchar == TELOPT_OLD_ENVIRON) {
1379                         if (c == env_ovar)
1380                                 c = NEW_ENV_VAR;
1381                         else if (c == env_ovalue)
1382                                 c = NEW_ENV_VALUE;
1383                 }
1384                 switch (c) {
1385
1386                 case NEW_ENV_VALUE:
1387                         *cp = '\0';
1388                         cp = valp = (char *)subpointer;
1389                         break;
1390
1391                 case NEW_ENV_VAR:
1392                 case ENV_USERVAR:
1393                         *cp = '\0';
1394                         if (valp)
1395                                 (void)setenv(varp, valp, 1);
1396                         else
1397                                 unsetenv(varp);
1398                         cp = varp = (char *)subpointer;
1399                         valp = 0;
1400                         break;
1401
1402                 case ENV_ESC:
1403                         if (SB_EOF())
1404                                 break;
1405                         c = SB_GET();
1406                         /* FALL THROUGH */
1407                 default:
1408                         *cp++ = c;
1409                         break;
1410                 }
1411         }
1412         *cp = '\0';
1413         if (valp)
1414                 (void)setenv(varp, valp, 1);
1415         else
1416                 unsetenv(varp);
1417         break;
1418     }  /* end of case TELOPT_NEW_ENVIRON */
1419 #if     defined(AUTHENTICATION)
1420     case TELOPT_AUTHENTICATION:
1421         if (SB_EOF())
1422                 break;
1423         switch(SB_GET()) {
1424         case TELQUAL_SEND:
1425         case TELQUAL_REPLY:
1426                 /*
1427                  * These are sent by us and cannot be sent by
1428                  * the client.
1429                  */
1430                 break;
1431         case TELQUAL_IS:
1432                 auth_is(subpointer, SB_LEN());
1433                 break;
1434         case TELQUAL_NAME:
1435                 auth_name(subpointer, SB_LEN());
1436                 break;
1437         }
1438         break;
1439 #endif
1440
1441     default:
1442         break;
1443     }  /* end of switch */
1444
1445 }  /* end of suboption */
1446
1447         void
1448 doclientstat()
1449 {
1450         clientstat(TELOPT_LINEMODE, WILL, 0);
1451 }
1452
1453 #define ADD(c)   *ncp++ = c
1454 #define ADD_DATA(c) { *ncp++ = c; if (c == SE) *ncp++ = c; }
1455         void
1456 send_status()
1457 {
1458         unsigned char statusbuf[256];
1459         register unsigned char *ncp;
1460         register unsigned char i;
1461
1462         ncp = statusbuf;
1463
1464         netflush();     /* get rid of anything waiting to go out */
1465
1466         ADD(IAC);
1467         ADD(SB);
1468         ADD(TELOPT_STATUS);
1469         ADD(TELQUAL_IS);
1470
1471         /*
1472          * We check the want_state rather than the current state,
1473          * because if we received a DO/WILL for an option that we
1474          * don't support, and the other side didn't send a DONT/WONT
1475          * in response to our WONT/DONT, then the "state" will be
1476          * WILL/DO, and the "want_state" will be WONT/DONT.  We
1477          * need to go by the latter.
1478          */
1479         for (i = 0; i < (unsigned char)NTELOPTS; i++) {
1480                 if (my_want_state_is_will(i)) {
1481                         ADD(WILL);
1482                         ADD_DATA(i);
1483                         if (i == IAC)
1484                                 ADD(IAC);
1485                 }
1486                 if (his_want_state_is_will(i)) {
1487                         ADD(DO);
1488                         ADD_DATA(i);
1489                         if (i == IAC)
1490                                 ADD(IAC);
1491                 }
1492         }
1493
1494         if (his_want_state_is_will(TELOPT_LFLOW)) {
1495                 ADD(SB);
1496                 ADD(TELOPT_LFLOW);
1497                 if (flowmode) {
1498                         ADD(LFLOW_ON);
1499                 } else {
1500                         ADD(LFLOW_OFF);
1501                 }
1502                 ADD(SE);
1503
1504                 if (restartany >= 0) {
1505                         ADD(SB);
1506                         ADD(TELOPT_LFLOW);
1507                         if (restartany) {
1508                                 ADD(LFLOW_RESTART_ANY);
1509                         } else {
1510                                 ADD(LFLOW_RESTART_XON);
1511                         }
1512                         ADD(SE);
1513                         ADD(SB);
1514                 }
1515         }
1516
1517 #ifdef  LINEMODE
1518         if (his_want_state_is_will(TELOPT_LINEMODE)) {
1519                 unsigned char *cp, *cpe;
1520                 int len;
1521
1522                 ADD(SB);
1523                 ADD(TELOPT_LINEMODE);
1524                 ADD(LM_MODE);
1525                 ADD_DATA(editmode);
1526                 if (editmode == IAC)
1527                         ADD(IAC);
1528                 ADD(SE);
1529
1530                 ADD(SB);
1531                 ADD(TELOPT_LINEMODE);
1532                 ADD(LM_SLC);
1533                 start_slc(0);
1534                 send_slc();
1535                 len = end_slc(&cp);
1536                 for (cpe = cp + len; cp < cpe; cp++)
1537                         ADD_DATA(*cp);
1538                 ADD(SE);
1539         }
1540 #endif  /* LINEMODE */
1541
1542         ADD(IAC);
1543         ADD(SE);
1544
1545         writenet(statusbuf, ncp - statusbuf);
1546         netflush();     /* Send it on its way */
1547
1548         DIAG(TD_OPTIONS,
1549                 {printsub('>', statusbuf, ncp - statusbuf); netflush();});
1550 }