crypto/telnet/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 const char sccsid[] = "@(#)state.c       8.5 (Berkeley) 5/30/95";
  37 #endif
  38 static const char rcsid[] =
  39   "$FreeBSD$";
  40 #endif /* not lint */
  41
  42 #include "telnetd.h"
  43 #if     defined(AUTHENTICATION)
  44 #include <libtelnet/auth.h>
  45 #endif
  46 #if     defined(ENCRYPTION)
  47 #include <libtelnet/encrypt.h>
  48 #endif
  49
  50 unsigned char   doopt[] = { IAC, DO, '%', 'c', 0 };
  51 unsigned char   dont[] = { IAC, DONT, '%', 'c', 0 };
  52 unsigned char   will[] = { IAC, WILL, '%', 'c', 0 };
  53 unsigned char   wont[] = { IAC, WONT, '%', 'c', 0 };
  54 int     not42 = 1;
  55
  56 /*
  57  * Buffer for sub-options, and macros
  58  * for suboptions buffer manipulations
  59  */
  60 unsigned char subbuffer[512], *subpointer= subbuffer, *subend= subbuffer;
  61
  62 #define SB_CLEAR()      subpointer = subbuffer
  63 #define SB_TERM()       { subend = subpointer; SB_CLEAR(); }
  64 #define SB_ACCUM(c)     if (subpointer < (subbuffer+sizeof subbuffer)) { \
  65                                 *subpointer++ = (c); \
  66                         }
  67 #define SB_GET()        ((*subpointer++)&0xff)
  68 #define SB_EOF()        (subpointer >= subend)
  69 #define SB_LEN()        (subend - subpointer)
  70
  71 #ifdef  ENV_HACK
  72 unsigned char *subsave;
  73 #define SB_SAVE()       subsave = subpointer;
  74 #define SB_RESTORE()    subpointer = subsave;
  75 #endif
  76
  77
  78 /*
  79  * State for recv fsm
  80  */
  81 #define TS_DATA         0       /* base state */
  82 #define TS_IAC          1       /* look for double IAC's */
  83 #define TS_CR           2       /* CR-LF ->'s CR */
  84 #define TS_SB           3       /* throw away begin's... */
  85 #define TS_SE           4       /* ...end's (suboption negotiation) */
  86 #define TS_WILL         5       /* will option negotiation */
  87 #define TS_WONT         6       /* wont " */
  88 #define TS_DO           7       /* do " */
  89 #define TS_DONT         8       /* dont " */
  90
  91         void
  92 telrcv()
  93 {
  94         register int c;
  95         static int state = TS_DATA;
  96 #if     defined(CRAY2) && defined(UNICOS5)
  97         char *opfrontp = pfrontp;
  98 #endif
  99
 100         while (ncc > 0) {
 101                 if ((&ptyobuf[BUFSIZ] - pfrontp) < 2)
 102                         break;
 103                 c = *netip++ & 0377, ncc--;
 104 #ifdef  ENCRYPTION
 105                 if (decrypt_input)
 106                         c = (*decrypt_input)(c);
 107 #endif  /* ENCRYPTION */
 108                 switch (state) {
 109
 110                 case TS_CR:
 111                         state = TS_DATA;
 112                         /* Strip off \n or \0 after a \r */
 113                         if ((c == 0) || (c == '\n')) {
 114                                 break;
 115                         }
 116                         /* FALL THROUGH */
 117
 118                 case TS_DATA:
 119                         if (c == IAC) {
 120                                 state = TS_IAC;
 121                                 break;
 122                         }
 123                         /*
 124                          * We now map \r\n ==> \r for pragmatic reasons.
 125                          * Many client implementations send \r\n when
 126                          * the user hits the CarriageReturn key.
 127                          *
 128                          * We USED to map \r\n ==> \n, since \r\n says
 129                          * that we want to be in column 1 of the next
 130                          * printable line, and \n is the standard
 131                          * unix way of saying that (\r is only good
 132                          * if CRMOD is set, which it normally is).
 133                          */
 134                         if ((c == '\r') && his_state_is_wont(TELOPT_BINARY)) {
 135                                 int nc = *netip;
 136 #ifdef  ENCRYPTION
 137                                 if (decrypt_input)
 138                                         nc = (*decrypt_input)(nc & 0xff);
 139 #endif  /* ENCRYPTION */
 140 #ifdef  LINEMODE
 141                                 /*
 142                                  * If we are operating in linemode,
 143                                  * convert to local end-of-line.
 144                                  */
 145                                 if (linemode && (ncc > 0) && (('\n' == nc) ||
 146                                          ((0 == nc) && tty_iscrnl())) ) {
 147                                         netip++; ncc--;
 148                                         c = '\n';
 149                                 } else
 150 #endif
 151                                 {
 152 #ifdef  ENCRYPTION
 153                                         if (decrypt_input)
 154                                                 (void)(*decrypt_input)(-1);
 155 #endif  /* ENCRYPTION */
 156                                         state = TS_CR;
 157                                 }
 158                         }
 159                         *pfrontp++ = c;
 160                         break;
 161
 162                 case TS_IAC:
 163 gotiac:                 switch (c) {
 164
 165                         /*
 166                          * Send the process on the pty side an
 167                          * interrupt.  Do this with a NULL or
 168                          * interrupt char; depending on the tty mode.
 169                          */
 170                         case IP:
 171                                 DIAG(TD_OPTIONS,
 172                                         printoption("td: recv IAC", c));
 173                                 interrupt();
 174                                 break;
 175
 176                         case BREAK:
 177                                 DIAG(TD_OPTIONS,
 178                                         printoption("td: recv IAC", c));
 179                                 sendbrk();
 180                                 break;
 181
 182                         /*
 183                          * Are You There?
 184                          */
 185                         case AYT:
 186                                 DIAG(TD_OPTIONS,
 187                                         printoption("td: recv IAC", c));
 188                                 recv_ayt();
 189                                 break;
 190
 191                         /*
 192                          * Abort Output
 193                          */
 194                         case AO:
 195                             {
 196                                 DIAG(TD_OPTIONS,
 197                                         printoption("td: recv IAC", c));
 198                                 ptyflush();     /* half-hearted */
 199                                 init_termbuf();
 200
 201                                 if (slctab[SLC_AO].sptr &&
 202                                     *slctab[SLC_AO].sptr != (cc_t)(_POSIX_VDISABLE)) {
 203                                     *pfrontp++ =
 204                                         (unsigned char)*slctab[SLC_AO].sptr;
 205                                 }
 206
 207                                 netclear();     /* clear buffer back */
 208                                 *nfrontp++ = IAC;
 209                                 *nfrontp++ = DM;
 210                                 neturg = nfrontp-1; /* off by one XXX */
 211                                 DIAG(TD_OPTIONS,
 212                                         printoption("td: send IAC", DM));
 213                                 break;
 214                             }
 215
 216                         /*
 217                          * Erase Character and
 218                          * Erase Line
 219                          */
 220                         case EC:
 221                         case EL:
 222                             {
 223                                 cc_t ch;
 224
 225                                 DIAG(TD_OPTIONS,
 226                                         printoption("td: recv IAC", c));
 227                                 ptyflush();     /* half-hearted */
 228                                 init_termbuf();
 229                                 if (c == EC)
 230                                         ch = *slctab[SLC_EC].sptr;
 231                                 else
 232                                         ch = *slctab[SLC_EL].sptr;
 233                                 if (ch != (cc_t)(_POSIX_VDISABLE))
 234                                         *pfrontp++ = (unsigned char)ch;
 235                                 break;
 236                             }
 237
 238                         /*
 239                          * Check for urgent data...
 240                          */
 241                         case DM:
 242                                 DIAG(TD_OPTIONS,
 243                                         printoption("td: recv IAC", c));
 244                                 SYNCHing = stilloob(net);
 245                                 settimer(gotDM);
 246                                 break;
 247
 248
 249                         /*
 250                          * Begin option subnegotiation...
 251                          */
 252                         case SB:
 253                                 state = TS_SB;
 254                                 SB_CLEAR();
 255                                 continue;
 256
 257                         case WILL:
 258                                 state = TS_WILL;
 259                                 continue;
 260
 261                         case WONT:
 262                                 state = TS_WONT;
 263                                 continue;
 264
 265                         case DO:
 266                                 state = TS_DO;
 267                                 continue;
 268
 269                         case DONT:
 270                                 state = TS_DONT;
 271                                 continue;
 272                         case EOR:
 273                                 if (his_state_is_will(TELOPT_EOR))
 274                                         doeof();
 275                                 break;
 276
 277                         /*
 278                          * Handle RFC 10xx Telnet linemode option additions
 279                          * to command stream (EOF, SUSP, ABORT).
 280                          */
 281                         case xEOF:
 282                                 doeof();
 283                                 break;
 284
 285                         case SUSP:
 286                                 sendsusp();
 287                                 break;
 288
 289                         case ABORT:
 290                                 sendbrk();
 291                                 break;
 292
 293                         case IAC:
 294                                 *pfrontp++ = c;
 295                                 break;
 296                         }
 297                         state = TS_DATA;
 298                         break;
 299
 300                 case TS_SB:
 301                         if (c == IAC) {
 302                                 state = TS_SE;
 303                         } else {
 304                                 SB_ACCUM(c);
 305                         }
 306                         break;
 307
 308                 case TS_SE:
 309                         if (c != SE) {
 310                                 if (c != IAC) {
 311                                         /*
 312                                          * bad form of suboption negotiation.
 313                                          * handle it in such a way as to avoid
 314                                          * damage to local state.  Parse
 315                                          * suboption buffer found so far,
 316                                          * then treat remaining stream as
 317                                          * another command sequence.
 318                                          */
 319
 320                                         /* for DIAGNOSTICS */
 321                                         SB_ACCUM(IAC);
 322                                         SB_ACCUM(c);
 323                                         subpointer -= 2;
 324
 325                                         SB_TERM();
 326                                         suboption();
 327                                         state = TS_IAC;
 328                                         goto gotiac;
 329                                 }
 330                                 SB_ACCUM(c);
 331                                 state = TS_SB;
 332                         } else {
 333                                 /* for DIAGNOSTICS */
 334                                 SB_ACCUM(IAC);
 335                                 SB_ACCUM(SE);
 336                                 subpointer -= 2;
 337
 338                                 SB_TERM();
 339                                 suboption();    /* handle sub-option */
 340                                 state = TS_DATA;
 341                         }
 342                         break;
 343
 344                 case TS_WILL:
 345                         willoption(c);
 346                         state = TS_DATA;
 347                         continue;
 348
 349                 case TS_WONT:
 350                         wontoption(c);
 351                         state = TS_DATA;
 352                         continue;
 353
 354                 case TS_DO:
 355                         dooption(c);
 356                         state = TS_DATA;
 357                         continue;
 358
 359                 case TS_DONT:
 360                         dontoption(c);
 361                         state = TS_DATA;
 362                         continue;
 363
 364                 default:
 365                         syslog(LOG_ERR, "panic state=%d", state);
 366                         printf("telnetd: panic state=%d\n", state);
 367                         exit(1);
 368                 }
 369         }
 370 #if     defined(CRAY2) && defined(UNICOS5)
 371         if (!linemode) {
 372                 char    xptyobuf[BUFSIZ+NETSLOP];
 373                 char    xbuf2[BUFSIZ];
 374                 register char *cp;
 375                 int n = pfrontp - opfrontp, oc;
 376                 memmove(xptyobuf, opfrontp, n);
 377                 pfrontp = opfrontp;
 378                 pfrontp += term_input(xptyobuf, pfrontp, n, BUFSIZ+NETSLOP,
 379                                         xbuf2, &oc, BUFSIZ);
 380                 for (cp = xbuf2; oc > 0; --oc)
 381                         if ((*nfrontp++ = *cp++) == IAC)
 382                                 *nfrontp++ = IAC;
 383         }
 384 #endif  /* defined(CRAY2) && defined(UNICOS5) */
 385 }  /* end of telrcv */
 386
 387 /*
 388  * The will/wont/do/dont state machines are based on Dave Borman's
 389  * Telnet option processing state machine.
 390  *
 391  * These correspond to the following states:
 392  *      my_state = the last negotiated state
 393  *      want_state = what I want the state to go to
 394  *      want_resp = how many requests I have sent
 395  * All state defaults are negative, and resp defaults to 0.
 396  *
 397  * When initiating a request to change state to new_state:
 398  *
 399  * if ((want_resp == 0 && new_state == my_state) || want_state == new_state) {
 400  *      do nothing;
 401  * } else {
 402  *      want_state = new_state;
 403  *      send new_state;
 404  *      want_resp++;
 405  * }
 406  *
 407  * When receiving new_state:
 408  *
 409  * if (want_resp) {
 410  *      want_resp--;
 411  *      if (want_resp && (new_state == my_state))
 412  *              want_resp--;
 413  * }
 414  * if ((want_resp == 0) && (new_state != want_state)) {
 415  *      if (ok_to_switch_to new_state)
 416  *              want_state = new_state;
 417  *      else
 418  *              want_resp++;
 419  *      send want_state;
 420  * }
 421  * my_state = new_state;
 422  *
 423  * Note that new_state is implied in these functions by the function itself.
 424  * will and do imply positive new_state, wont and dont imply negative.
 425  *
 426  * Finally, there is one catch.  If we send a negative response to a
 427  * positive request, my_state will be the positive while want_state will
 428  * remain negative.  my_state will revert to negative when the negative
 429  * acknowlegment arrives from the peer.  Thus, my_state generally tells
 430  * us not only the last negotiated state, but also tells us what the peer
 431  * wants to be doing as well.  It is important to understand this difference
 432  * as we may wish to be processing data streams based on our desired state
 433  * (want_state) or based on what the peer thinks the state is (my_state).
 434  *
 435  * This all works fine because if the peer sends a positive request, the data
 436  * that we receive prior to negative acknowlegment will probably be affected
 437  * by the positive state, and we can process it as such (if we can; if we
 438  * can't then it really doesn't matter).  If it is that important, then the
 439  * peer probably should be buffering until this option state negotiation
 440  * is complete.
 441  *
 442  */
 443         void
 444 send_do(option, init)
 445         int option, init;
 446 {
 447         if (init) {
 448                 if ((do_dont_resp[option] == 0 && his_state_is_will(option)) ||
 449                     his_want_state_is_will(option))
 450                         return;
 451                 /*
 452                  * Special case for TELOPT_TM:  We send a DO, but pretend
 453                  * that we sent a DONT, so that we can send more DOs if
 454                  * we want to.
 455                  */
 456                 if (option == TELOPT_TM)
 457                         set_his_want_state_wont(option);
 458                 else
 459                         set_his_want_state_will(option);
 460                 do_dont_resp[option]++;
 461         }
 462         (void) sprintf(nfrontp, (char *)doopt, option);
 463         nfrontp += sizeof (dont) - 2;
 464
 465         DIAG(TD_OPTIONS, printoption("td: send do", option));
 466 }
 467
 468 #ifdef  AUTHENTICATION
 469 extern void auth_request();
 470 #endif
 471 #ifdef  LINEMODE
 472 extern void doclientstat();
 473 #endif
 474 #ifdef  ENCRYPTION
 475 extern void encrypt_send_support();
 476 #endif  /* ENCRYPTION */
 477
 478         void
 479 willoption(option)
 480         int option;
 481 {
 482         int changeok = 0;
 483         void (*func)() = 0;
 484
 485         /*
 486          * process input from peer.
 487          */
 488
 489         DIAG(TD_OPTIONS, printoption("td: recv will", option));
 490
 491         if (do_dont_resp[option]) {
 492                 do_dont_resp[option]--;
 493                 if (do_dont_resp[option] && his_state_is_will(option))
 494                         do_dont_resp[option]--;
 495         }
 496         if (do_dont_resp[option] == 0) {
 497             if (his_want_state_is_wont(option)) {
 498                 switch (option) {
 499
 500                 case TELOPT_BINARY:
 501                         init_termbuf();
 502                         tty_binaryin(1);
 503                         set_termbuf();
 504                         changeok++;
 505                         break;
 506
 507                 case TELOPT_ECHO:
 508                         /*
 509                          * See comments below for more info.
 510                          */
 511                         not42 = 0;      /* looks like a 4.2 system */
 512                         break;
 513
 514                 case TELOPT_TM:
 515 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
 516                         /*
 517                          * This telnetd implementation does not really
 518                          * support timing marks, it just uses them to
 519                          * support the kludge linemode stuff.  If we
 520                          * receive a will or wont TM in response to our
 521                          * do TM request that may have been sent to
 522                          * determine kludge linemode support, process
 523                          * it, otherwise TM should get a negative
 524                          * response back.
 525                          */
 526                         /*
 527                          * Handle the linemode kludge stuff.
 528                          * If we are not currently supporting any
 529                          * linemode at all, then we assume that this
 530                          * is the client telling us to use kludge
 531                          * linemode in response to our query.  Set the
 532                          * linemode type that is to be supported, note
 533                          * that the client wishes to use linemode, and
 534                          * eat the will TM as though it never arrived.
 535                          */
 536                         if (lmodetype < KLUDGE_LINEMODE) {
 537                                 lmodetype = KLUDGE_LINEMODE;
 538                                 clientstat(TELOPT_LINEMODE, WILL, 0);
 539                                 send_wont(TELOPT_SGA, 1);
 540                         } else if (lmodetype == NO_AUTOKLUDGE) {
 541                                 lmodetype = KLUDGE_OK;
 542                         }
 543 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
 544                         /*
 545                          * We never respond to a WILL TM, and
 546                          * we leave the state WONT.
 547                          */
 548                         return;
 549
 550                 case TELOPT_LFLOW:
 551                         /*
 552                          * If we are going to support flow control
 553                          * option, then don't worry peer that we can't
 554                          * change the flow control characters.
 555                          */
 556                         slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
 557                         slctab[SLC_XON].defset.flag |= SLC_DEFAULT;
 558                         slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
 559                         slctab[SLC_XOFF].defset.flag |= SLC_DEFAULT;
 560                 case TELOPT_TTYPE:
 561                 case TELOPT_SGA:
 562                 case TELOPT_NAWS:
 563                 case TELOPT_TSPEED:
 564                 case TELOPT_XDISPLOC:
 565                 case TELOPT_NEW_ENVIRON:
 566                 case TELOPT_OLD_ENVIRON:
 567                         changeok++;
 568                         break;
 569
 570 #ifdef  LINEMODE
 571                 case TELOPT_LINEMODE:
 572 # ifdef KLUDGELINEMODE
 573                         /*
 574                          * Note client's desire to use linemode.
 575                          */
 576                         lmodetype = REAL_LINEMODE;
 577 # endif /* KLUDGELINEMODE */
 578                         func = doclientstat;
 579                         changeok++;
 580                         break;
 581 #endif  /* LINEMODE */
 582
 583 #ifdef  AUTHENTICATION
 584                 case TELOPT_AUTHENTICATION:
 585                         func = auth_request;
 586                         changeok++;
 587                         break;
 588 #endif
 589
 590 #ifdef  ENCRYPTION
 591                 case TELOPT_ENCRYPT:
 592                         func = encrypt_send_support;
 593                         changeok++;
 594                         break;
 595 #endif  /* ENCRYPTION */
 596
 597                 default:
 598                         break;
 599                 }
 600                 if (changeok) {
 601                         set_his_want_state_will(option);
 602                         send_do(option, 0);
 603                 } else {
 604                         do_dont_resp[option]++;
 605                         send_dont(option, 0);
 606                 }
 607             } else {
 608                 /*
 609                  * Option processing that should happen when
 610                  * we receive conformation of a change in
 611                  * state that we had requested.
 612                  */
 613                 switch (option) {
 614                 case TELOPT_ECHO:
 615                         not42 = 0;      /* looks like a 4.2 system */
 616                         /*
 617                          * Egads, he responded "WILL ECHO".  Turn
 618                          * it off right now!
 619                          */
 620                         send_dont(option, 1);
 621                         /*
 622                          * "WILL ECHO".  Kludge upon kludge!
 623                          * A 4.2 client is now echoing user input at
 624                          * the tty.  This is probably undesireable and
 625                          * it should be stopped.  The client will
 626                          * respond WONT TM to the DO TM that we send to
 627                          * check for kludge linemode.  When the WONT TM
 628                          * arrives, linemode will be turned off and a
 629                          * change propogated to the pty.  This change
 630                          * will cause us to process the new pty state
 631                          * in localstat(), which will notice that
 632                          * linemode is off and send a WILL ECHO
 633                          * so that we are properly in character mode and
 634                          * all is well.
 635                          */
 636                         break;
 637 #ifdef  LINEMODE
 638                 case TELOPT_LINEMODE:
 639 # ifdef KLUDGELINEMODE
 640                         /*
 641                          * Note client's desire to use linemode.
 642                          */
 643                         lmodetype = REAL_LINEMODE;
 644 # endif /* KLUDGELINEMODE */
 645                         func = doclientstat;
 646                         break;
 647 #endif  /* LINEMODE */
 648
 649 #ifdef  AUTHENTICATION
 650                 case TELOPT_AUTHENTICATION:
 651                         func = auth_request;
 652                         break;
 653 #endif
 654
 655 #ifdef  ENCRYPTION
 656                 case TELOPT_ENCRYPT:
 657                         func = encrypt_send_support;
 658                         break;
 659 #endif  /* ENCRYPTION */
 660                 case TELOPT_LFLOW:
 661                         func = flowstat;
 662                         break;
 663                 }
 664             }
 665         }
 666         set_his_state_will(option);
 667         if (func)
 668                 (*func)();
 669 }  /* end of willoption */
 670
 671         void
 672 send_dont(option, init)
 673         int option, init;
 674 {
 675         if (init) {
 676                 if ((do_dont_resp[option] == 0 && his_state_is_wont(option)) ||
 677                     his_want_state_is_wont(option))
 678                         return;
 679                 set_his_want_state_wont(option);
 680                 do_dont_resp[option]++;
 681         }
 682         (void) sprintf(nfrontp, (char *)dont, option);
 683         nfrontp += sizeof (doopt) - 2;
 684
 685         DIAG(TD_OPTIONS, printoption("td: send dont", option));
 686 }
 687
 688         void
 689 wontoption(option)
 690         int option;
 691 {
 692         /*
 693          * Process client input.
 694          */
 695
 696         DIAG(TD_OPTIONS, printoption("td: recv wont", option));
 697
 698         if (do_dont_resp[option]) {
 699                 do_dont_resp[option]--;
 700                 if (do_dont_resp[option] && his_state_is_wont(option))
 701                         do_dont_resp[option]--;
 702         }
 703         if (do_dont_resp[option] == 0) {
 704             if (his_want_state_is_will(option)) {
 705                 /* it is always ok to change to negative state */
 706                 switch (option) {
 707                 case TELOPT_ECHO:
 708                         not42 = 1; /* doesn't seem to be a 4.2 system */
 709                         break;
 710
 711                 case TELOPT_BINARY:
 712                         init_termbuf();
 713                         tty_binaryin(0);
 714                         set_termbuf();
 715                         break;
 716
 717 #ifdef  LINEMODE
 718                 case TELOPT_LINEMODE:
 719 # ifdef KLUDGELINEMODE
 720                         /*
 721                          * If real linemode is supported, then client is
 722                          * asking to turn linemode off.
 723                          */
 724                         if (lmodetype != REAL_LINEMODE)
 725                                 break;
 726 # endif /* KLUDGELINEMODE */
 727                         clientstat(TELOPT_LINEMODE, WONT, 0);
 728                         break;
 729 #endif  /* LINEMODE */
 730
 731                 case TELOPT_TM:
 732                         /*
 733                          * If we get a WONT TM, and had sent a DO TM,
 734                          * don't respond with a DONT TM, just leave it
 735                          * as is.  Short circut the state machine to
 736                          * achive this.
 737                          */
 738                         set_his_want_state_wont(TELOPT_TM);
 739                         return;
 740
 741                 case TELOPT_LFLOW:
 742                         /*
 743                          * If we are not going to support flow control
 744                          * option, then let peer know that we can't
 745                          * change the flow control characters.
 746                          */
 747                         slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
 748                         slctab[SLC_XON].defset.flag |= SLC_CANTCHANGE;
 749                         slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
 750                         slctab[SLC_XOFF].defset.flag |= SLC_CANTCHANGE;
 751                         break;
 752
 753 #if     defined(AUTHENTICATION)
 754                 case TELOPT_AUTHENTICATION:
 755                         auth_finished(0, AUTH_REJECT);
 756                         break;
 757 #endif
 758
 759                 /*
 760                  * For options that we might spin waiting for
 761                  * sub-negotiation, if the client turns off the
 762                  * option rather than responding to the request,
 763                  * we have to treat it here as if we got a response
 764                  * to the sub-negotiation, (by updating the timers)
 765                  * so that we'll break out of the loop.
 766                  */
 767                 case TELOPT_TTYPE:
 768                         settimer(ttypesubopt);
 769                         break;
 770
 771                 case TELOPT_TSPEED:
 772                         settimer(tspeedsubopt);
 773                         break;
 774
 775                 case TELOPT_XDISPLOC:
 776                         settimer(xdisplocsubopt);
 777                         break;
 778
 779                 case TELOPT_OLD_ENVIRON:
 780                         settimer(oenvironsubopt);
 781                         break;
 782
 783                 case TELOPT_NEW_ENVIRON:
 784                         settimer(environsubopt);
 785                         break;
 786
 787                 default:
 788                         break;
 789                 }
 790                 set_his_want_state_wont(option);
 791                 if (his_state_is_will(option))
 792                         send_dont(option, 0);
 793             } else {
 794                 switch (option) {
 795                 case TELOPT_TM:
 796 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
 797                         if (lmodetype < NO_AUTOKLUDGE) {
 798                                 lmodetype = NO_LINEMODE;
 799                                 clientstat(TELOPT_LINEMODE, WONT, 0);
 800                                 send_will(TELOPT_SGA, 1);
 801                                 send_will(TELOPT_ECHO, 1);
 802                         }
 803 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
 804                         break;
 805
 806 #if     defined(AUTHENTICATION)
 807                 case TELOPT_AUTHENTICATION:
 808                         auth_finished(0, AUTH_REJECT);
 809                         break;
 810 #endif
 811                 default:
 812                         break;
 813                 }
 814             }
 815         }
 816         set_his_state_wont(option);
 817
 818 }  /* end of wontoption */
 819
 820         void
 821 send_will(option, init)
 822         int option, init;
 823 {
 824         if (init) {
 825                 if ((will_wont_resp[option] == 0 && my_state_is_will(option))||
 826                     my_want_state_is_will(option))
 827                         return;
 828                 set_my_want_state_will(option);
 829                 will_wont_resp[option]++;
 830         }
 831         (void) sprintf(nfrontp, (char *)will, option);
 832         nfrontp += sizeof (doopt) - 2;
 833
 834         DIAG(TD_OPTIONS, printoption("td: send will", option));
 835 }
 836
 837 #if     !defined(LINEMODE) || !defined(KLUDGELINEMODE)
 838 /*
 839  * When we get a DONT SGA, we will try once to turn it
 840  * back on.  If the other side responds DONT SGA, we
 841  * leave it at that.  This is so that when we talk to
 842  * clients that understand KLUDGELINEMODE but not LINEMODE,
 843  * we'll keep them in char-at-a-time mode.
 844  */
 845 int turn_on_sga = 0;
 846 #endif
 847
 848         void
 849 dooption(option)
 850         int option;
 851 {
 852         int changeok = 0;
 853
 854         /*
 855          * Process client input.
 856          */
 857
 858         DIAG(TD_OPTIONS, printoption("td: recv do", option));
 859
 860         if (will_wont_resp[option]) {
 861                 will_wont_resp[option]--;
 862                 if (will_wont_resp[option] && my_state_is_will(option))
 863                         will_wont_resp[option]--;
 864         }
 865         if ((will_wont_resp[option] == 0) && (my_want_state_is_wont(option))) {
 866                 switch (option) {
 867                 case TELOPT_ECHO:
 868 #ifdef  LINEMODE
 869 # ifdef KLUDGELINEMODE
 870                         if (lmodetype == NO_LINEMODE)
 871 # else
 872                         if (his_state_is_wont(TELOPT_LINEMODE))
 873 # endif
 874 #endif
 875                         {
 876                                 init_termbuf();
 877                                 tty_setecho(1);
 878                                 set_termbuf();
 879                         }
 880                         changeok++;
 881                         break;
 882
 883                 case TELOPT_BINARY:
 884                         init_termbuf();
 885                         tty_binaryout(1);
 886                         set_termbuf();
 887                         changeok++;
 888                         break;
 889
 890                 case TELOPT_SGA:
 891 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
 892                         /*
 893                          * If kludge linemode is in use, then we must
 894                          * process an incoming do SGA for linemode
 895                          * purposes.
 896                          */
 897                         if (lmodetype == KLUDGE_LINEMODE) {
 898                                 /*
 899                                  * Receipt of "do SGA" in kludge
 900                                  * linemode is the peer asking us to
 901                                  * turn off linemode.  Make note of
 902                                  * the request.
 903                                  */
 904                                 clientstat(TELOPT_LINEMODE, WONT, 0);
 905                                 /*
 906                                  * If linemode did not get turned off
 907                                  * then don't tell peer that we did.
 908                                  * Breaking here forces a wont SGA to
 909                                  * be returned.
 910                                  */
 911                                 if (linemode)
 912                                         break;
 913                         }
 914 #else
 915                         turn_on_sga = 0;
 916 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
 917                         changeok++;
 918                         break;
 919
 920                 case TELOPT_STATUS:
 921                         changeok++;
 922                         break;
 923
 924                 case TELOPT_TM:
 925                         /*
 926                          * Special case for TM.  We send a WILL, but
 927                          * pretend we sent a WONT.
 928                          */
 929                         send_will(option, 0);
 930                         set_my_want_state_wont(option);
 931                         set_my_state_wont(option);
 932                         return;
 933
 934                 case TELOPT_LOGOUT:
 935                         /*
 936                          * When we get a LOGOUT option, respond
 937                          * with a WILL LOGOUT, make sure that
 938                          * it gets written out to the network,
 939                          * and then just go away...
 940                          */
 941                         set_my_want_state_will(TELOPT_LOGOUT);
 942                         send_will(TELOPT_LOGOUT, 0);
 943                         set_my_state_will(TELOPT_LOGOUT);
 944                         (void)netflush();
 945                         cleanup(0);
 946                         /* NOT REACHED */
 947                         break;
 948
 949 #ifdef  ENCRYPTION
 950                 case TELOPT_ENCRYPT:
 951                         changeok++;
 952                         break;
 953 #endif  /* ENCRYPTION */
 954                 case TELOPT_LINEMODE:
 955                 case TELOPT_TTYPE:
 956                 case TELOPT_NAWS:
 957                 case TELOPT_TSPEED:
 958                 case TELOPT_LFLOW:
 959                 case TELOPT_XDISPLOC:
 960 #ifdef  TELOPT_ENVIRON
 961                 case TELOPT_NEW_ENVIRON:
 962 #endif
 963                 case TELOPT_OLD_ENVIRON:
 964                 default:
 965                         break;
 966                 }
 967                 if (changeok) {
 968                         set_my_want_state_will(option);
 969                         send_will(option, 0);
 970                 } else {
 971                         will_wont_resp[option]++;
 972                         send_wont(option, 0);
 973                 }
 974         }
 975         set_my_state_will(option);
 976
 977 }  /* end of dooption */
 978
 979         void
 980 send_wont(option, init)
 981         int option, init;
 982 {
 983         if (init) {
 984                 if ((will_wont_resp[option] == 0 && my_state_is_wont(option)) ||
 985                     my_want_state_is_wont(option))
 986                         return;
 987                 set_my_want_state_wont(option);
 988                 will_wont_resp[option]++;
 989         }
 990         (void) sprintf(nfrontp, (char *)wont, option);
 991         nfrontp += sizeof (wont) - 2;
 992
 993         DIAG(TD_OPTIONS, printoption("td: send wont", option));
 994 }
 995
 996         void
 997 dontoption(option)
 998         int option;
 999 {
1000         /*
1001          * Process client input.
1002          */
1003
1004
1005         DIAG(TD_OPTIONS, printoption("td: recv dont", option));
1006
1007         if (will_wont_resp[option]) {
1008                 will_wont_resp[option]--;
1009                 if (will_wont_resp[option] && my_state_is_wont(option))
1010                         will_wont_resp[option]--;
1011         }
1012         if ((will_wont_resp[option] == 0) && (my_want_state_is_will(option))) {
1013                 switch (option) {
1014                 case TELOPT_BINARY:
1015                         init_termbuf();
1016                         tty_binaryout(0);
1017                         set_termbuf();
1018                         break;
1019
1020                 case TELOPT_ECHO:       /* we should stop echoing */
1021 #ifdef  LINEMODE
1022 # ifdef KLUDGELINEMODE
1023                         if ((lmodetype != REAL_LINEMODE) &&
1024                             (lmodetype != KLUDGE_LINEMODE))
1025 # else
1026                         if (his_state_is_wont(TELOPT_LINEMODE))
1027 # endif
1028 #endif
1029                         {
1030                                 init_termbuf();
1031                                 tty_setecho(0);
1032                                 set_termbuf();
1033                         }
1034                         break;
1035
1036                 case TELOPT_SGA:
1037 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
1038                         /*
1039                          * If kludge linemode is in use, then we
1040                          * must process an incoming do SGA for
1041                          * linemode purposes.
1042                          */
1043                         if ((lmodetype == KLUDGE_LINEMODE) ||
1044                             (lmodetype == KLUDGE_OK)) {
1045                                 /*
1046                                  * The client is asking us to turn
1047                                  * linemode on.
1048                                  */
1049                                 lmodetype = KLUDGE_LINEMODE;
1050                                 clientstat(TELOPT_LINEMODE, WILL, 0);
1051                                 /*
1052                                  * If we did not turn line mode on,
1053                                  * then what do we say?  Will SGA?
1054                                  * This violates design of telnet.
1055                                  * Gross.  Very Gross.
1056                                  */
1057                         }
1058                         break;
1059 #else
1060                         set_my_want_state_wont(option);
1061                         if (my_state_is_will(option))
1062                                 send_wont(option, 0);
1063                         set_my_state_wont(option);
1064                         if (turn_on_sga ^= 1)
1065                                 send_will(option, 1);
1066                         return;
1067 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
1068
1069                 default:
1070                         break;
1071                 }
1072
1073                 set_my_want_state_wont(option);
1074                 if (my_state_is_will(option))
1075                         send_wont(option, 0);
1076         }
1077         set_my_state_wont(option);
1078
1079 }  /* end of dontoption */
1080
1081 #ifdef  ENV_HACK
1082 int env_ovar = -1;
1083 int env_ovalue = -1;
1084 #else   /* ENV_HACK */
1085 # define env_ovar OLD_ENV_VAR
1086 # define env_ovalue OLD_ENV_VALUE
1087 #endif  /* ENV_HACK */
1088
1089 /*
1090  * suboption()
1091  *
1092  *      Look at the sub-option buffer, and try to be helpful to the other
1093  * side.
1094  *
1095  *      Currently we recognize:
1096  *
1097  *      Terminal type is
1098  *      Linemode
1099  *      Window size
1100  *      Terminal speed
1101  */
1102         void
1103 suboption()
1104 {
1105     register int subchar;
1106
1107     DIAG(TD_OPTIONS, {netflush(); printsub('<', subpointer, SB_LEN()+2);});
1108
1109     subchar = SB_GET();
1110     switch (subchar) {
1111     case TELOPT_TSPEED: {
1112         register int xspeed, rspeed;
1113
1114         if (his_state_is_wont(TELOPT_TSPEED))   /* Ignore if option disabled */
1115                 break;
1116
1117         settimer(tspeedsubopt);
1118
1119         if (SB_EOF() || SB_GET() != TELQUAL_IS)
1120                 return;
1121
1122         xspeed = atoi((char *)subpointer);
1123
1124         while (SB_GET() != ',' && !SB_EOF());
1125         if (SB_EOF())
1126                 return;
1127
1128         rspeed = atoi((char *)subpointer);
1129         clientstat(TELOPT_TSPEED, xspeed, rspeed);
1130
1131         break;
1132
1133     }  /* end of case TELOPT_TSPEED */
1134
1135     case TELOPT_TTYPE: {                /* Yaaaay! */
1136         static char terminalname[41];
1137
1138         if (his_state_is_wont(TELOPT_TTYPE))    /* Ignore if option disabled */
1139                 break;
1140         settimer(ttypesubopt);
1141
1142         if (SB_EOF() || SB_GET() != TELQUAL_IS) {
1143             return;             /* ??? XXX but, this is the most robust */
1144         }
1145
1146         terminaltype = terminalname;
1147
1148         while ((terminaltype < (terminalname + sizeof terminalname-1)) &&
1149                                                                     !SB_EOF()) {
1150             register int c;
1151
1152             c = SB_GET();
1153             if (isupper(c)) {
1154                 c = tolower(c);
1155             }
1156             *terminaltype++ = c;    /* accumulate name */
1157         }
1158         *terminaltype = 0;
1159         terminaltype = terminalname;
1160         break;
1161     }  /* end of case TELOPT_TTYPE */
1162
1163     case TELOPT_NAWS: {
1164         register int xwinsize, ywinsize;
1165
1166         if (his_state_is_wont(TELOPT_NAWS))     /* Ignore if option disabled */
1167                 break;
1168
1169         if (SB_EOF())
1170                 return;
1171         xwinsize = SB_GET() << 8;
1172         if (SB_EOF())
1173                 return;
1174         xwinsize |= SB_GET();
1175         if (SB_EOF())
1176                 return;
1177         ywinsize = SB_GET() << 8;
1178         if (SB_EOF())
1179                 return;
1180         ywinsize |= SB_GET();
1181         clientstat(TELOPT_NAWS, xwinsize, ywinsize);
1182
1183         break;
1184
1185     }  /* end of case TELOPT_NAWS */
1186
1187 #ifdef  LINEMODE
1188     case TELOPT_LINEMODE: {
1189         register int request;
1190
1191         if (his_state_is_wont(TELOPT_LINEMODE)) /* Ignore if option disabled */
1192                 break;
1193         /*
1194          * Process linemode suboptions.
1195          */
1196         if (SB_EOF())
1197             break;              /* garbage was sent */
1198         request = SB_GET();     /* get will/wont */
1199
1200         if (SB_EOF())
1201             break;              /* another garbage check */
1202
1203         if (request == LM_SLC) {  /* SLC is not preceeded by WILL or WONT */
1204                 /*
1205                  * Process suboption buffer of slc's
1206                  */
1207                 start_slc(1);
1208                 do_opt_slc(subpointer, subend - subpointer);
1209                 (void) end_slc(0);
1210                 break;
1211         } else if (request == LM_MODE) {
1212                 if (SB_EOF())
1213                     return;
1214                 useeditmode = SB_GET();  /* get mode flag */
1215                 clientstat(LM_MODE, 0, 0);
1216                 break;
1217         }
1218
1219         if (SB_EOF())
1220             break;
1221         switch (SB_GET()) {  /* what suboption? */
1222         case LM_FORWARDMASK:
1223                 /*
1224                  * According to spec, only server can send request for
1225                  * forwardmask, and client can only return a positive response.
1226                  * So don't worry about it.
1227                  */
1228
1229         default:
1230                 break;
1231         }
1232         break;
1233     }  /* end of case TELOPT_LINEMODE */
1234 #endif
1235     case TELOPT_STATUS: {
1236         int mode;
1237
1238         if (SB_EOF())
1239             break;
1240         mode = SB_GET();
1241         switch (mode) {
1242         case TELQUAL_SEND:
1243             if (my_state_is_will(TELOPT_STATUS))
1244                 send_status();
1245             break;
1246
1247         case TELQUAL_IS:
1248             break;
1249
1250         default:
1251             break;
1252         }
1253         break;
1254     }  /* end of case TELOPT_STATUS */
1255
1256     case TELOPT_XDISPLOC: {
1257         if (SB_EOF() || SB_GET() != TELQUAL_IS)
1258                 return;
1259         settimer(xdisplocsubopt);
1260         subpointer[SB_LEN()] = '\0';
1261         (void)setenv("DISPLAY", (char *)subpointer, 1);
1262         break;
1263     }  /* end of case TELOPT_XDISPLOC */
1264
1265 #ifdef  TELOPT_NEW_ENVIRON
1266     case TELOPT_NEW_ENVIRON:
1267 #endif
1268     case TELOPT_OLD_ENVIRON: {
1269         register int c;
1270         register char *cp, *varp, *valp;
1271
1272         if (SB_EOF())
1273                 return;
1274         c = SB_GET();
1275         if (c == TELQUAL_IS) {
1276                 if (subchar == TELOPT_OLD_ENVIRON)
1277                         settimer(oenvironsubopt);
1278                 else
1279                         settimer(environsubopt);
1280         } else if (c != TELQUAL_INFO) {
1281                 return;
1282         }
1283
1284 #ifdef  TELOPT_NEW_ENVIRON
1285         if (subchar == TELOPT_NEW_ENVIRON) {
1286             while (!SB_EOF()) {
1287                 c = SB_GET();
1288                 if ((c == NEW_ENV_VAR) || (c == ENV_USERVAR))
1289                         break;
1290             }
1291         } else
1292 #endif
1293         {
1294 #ifdef  ENV_HACK
1295             /*
1296              * We only want to do this if we haven't already decided
1297              * whether or not the other side has its VALUE and VAR
1298              * reversed.
1299              */
1300             if (env_ovar < 0) {
1301                 register int last = -1;         /* invalid value */
1302                 int empty = 0;
1303                 int got_var = 0, got_value = 0, got_uservar = 0;
1304
1305                 /*
1306                  * The other side might have its VALUE and VAR values
1307                  * reversed.  To be interoperable, we need to determine
1308                  * which way it is.  If the first recognized character
1309                  * is a VAR or VALUE, then that will tell us what
1310                  * type of client it is.  If the fist recognized
1311                  * character is a USERVAR, then we continue scanning
1312                  * the suboption looking for two consecutive
1313                  * VAR or VALUE fields.  We should not get two
1314                  * consecutive VALUE fields, so finding two
1315                  * consecutive VALUE or VAR fields will tell us
1316                  * what the client is.
1317                  */
1318                 SB_SAVE();
1319                 while (!SB_EOF()) {
1320                         c = SB_GET();
1321                         switch(c) {
1322                         case OLD_ENV_VAR:
1323                                 if (last < 0 || last == OLD_ENV_VAR
1324                                     || (empty && (last == OLD_ENV_VALUE)))
1325                                         goto env_ovar_ok;
1326                                 got_var++;
1327                                 last = OLD_ENV_VAR;
1328                                 break;
1329                         case OLD_ENV_VALUE:
1330                                 if (last < 0 || last == OLD_ENV_VALUE
1331                                     || (empty && (last == OLD_ENV_VAR)))
1332                                         goto env_ovar_wrong;
1333                                 got_value++;
1334                                 last = OLD_ENV_VALUE;
1335                                 break;
1336                         case ENV_USERVAR:
1337                                 /* count strings of USERVAR as one */
1338                                 if (last != ENV_USERVAR)
1339                                         got_uservar++;
1340                                 if (empty) {
1341                                         if (last == OLD_ENV_VALUE)
1342                                                 goto env_ovar_ok;
1343                                         if (last == OLD_ENV_VAR)
1344                                                 goto env_ovar_wrong;
1345                                 }
1346                                 last = ENV_USERVAR;
1347                                 break;
1348                         case ENV_ESC:
1349                                 if (!SB_EOF())
1350                                         c = SB_GET();
1351                                 /* FALL THROUGH */
1352                         default:
1353                                 empty = 0;
1354                                 continue;
1355                         }
1356                         empty = 1;
1357                 }
1358                 if (empty) {
1359                         if (last == OLD_ENV_VALUE)
1360                                 goto env_ovar_ok;
1361                         if (last == OLD_ENV_VAR)
1362                                 goto env_ovar_wrong;
1363                 }
1364                 /*
1365                  * Ok, the first thing was a USERVAR, and there
1366                  * are not two consecutive VAR or VALUE commands,
1367                  * and none of the VAR or VALUE commands are empty.
1368                  * If the client has sent us a well-formed option,
1369                  * then the number of VALUEs received should always
1370                  * be less than or equal to the number of VARs and
1371                  * USERVARs received.
1372                  *
1373                  * If we got exactly as many VALUEs as VARs and
1374                  * USERVARs, the client has the same definitions.
1375                  *
1376                  * If we got exactly as many VARs as VALUEs and
1377                  * USERVARS, the client has reversed definitions.
1378                  */
1379                 if (got_uservar + got_var == got_value) {
1380             env_ovar_ok:
1381                         env_ovar = OLD_ENV_VAR;
1382                         env_ovalue = OLD_ENV_VALUE;
1383                 } else if (got_uservar + got_value == got_var) {
1384             env_ovar_wrong:
1385                         env_ovar = OLD_ENV_VALUE;
1386                         env_ovalue = OLD_ENV_VAR;
1387                         DIAG(TD_OPTIONS, {sprintf(nfrontp,
1388                                 "ENVIRON VALUE and VAR are reversed!\r\n");
1389                                 nfrontp += strlen(nfrontp);});
1390
1391                 }
1392             }
1393             SB_RESTORE();
1394 #endif
1395
1396             while (!SB_EOF()) {
1397                 c = SB_GET();
1398                 if ((c == env_ovar) || (c == ENV_USERVAR))
1399                         break;
1400             }
1401         }
1402
1403         if (SB_EOF())
1404                 return;
1405
1406         cp = varp = (char *)subpointer;
1407         valp = 0;
1408
1409         while (!SB_EOF()) {
1410                 c = SB_GET();
1411                 if (subchar == TELOPT_OLD_ENVIRON) {
1412                         if (c == env_ovar)
1413                                 c = NEW_ENV_VAR;
1414                         else if (c == env_ovalue)
1415                                 c = NEW_ENV_VALUE;
1416                 }
1417                 switch (c) {
1418
1419                 case NEW_ENV_VALUE:
1420                         *cp = '\0';
1421                         cp = valp = (char *)subpointer;
1422                         break;
1423
1424                 case NEW_ENV_VAR:
1425                 case ENV_USERVAR:
1426                         *cp = '\0';
1427                         if (valp)
1428                                 (void)setenv(varp, valp, 1);
1429                         else
1430                                 unsetenv(varp);
1431                         cp = varp = (char *)subpointer;
1432                         valp = 0;
1433                         break;
1434
1435                 case ENV_ESC:
1436                         if (SB_EOF())
1437                                 break;
1438                         c = SB_GET();
1439                         /* FALL THROUGH */
1440                 default:
1441                         *cp++ = c;
1442                         break;
1443                 }
1444         }
1445         *cp = '\0';
1446         if (valp)
1447                 (void)setenv(varp, valp, 1);
1448         else
1449                 unsetenv(varp);
1450         break;
1451     }  /* end of case TELOPT_NEW_ENVIRON */
1452 #if     defined(AUTHENTICATION)
1453     case TELOPT_AUTHENTICATION:
1454         if (SB_EOF())
1455                 break;
1456         switch(SB_GET()) {
1457         case TELQUAL_SEND:
1458         case TELQUAL_REPLY:
1459                 /*
1460                  * These are sent by us and cannot be sent by
1461                  * the client.
1462                  */
1463                 break;
1464         case TELQUAL_IS:
1465                 auth_is(subpointer, SB_LEN());
1466                 break;
1467         case TELQUAL_NAME:
1468                 auth_name(subpointer, SB_LEN());
1469                 break;
1470         }
1471         break;
1472 #endif
1473 #ifdef  ENCRYPTION
1474     case TELOPT_ENCRYPT:
1475         if (SB_EOF())
1476                 break;
1477         switch(SB_GET()) {
1478         case ENCRYPT_SUPPORT:
1479                 encrypt_support(subpointer, SB_LEN());
1480                 break;
1481         case ENCRYPT_IS:
1482                 encrypt_is(subpointer, SB_LEN());
1483                 break;
1484         case ENCRYPT_REPLY:
1485                 encrypt_reply(subpointer, SB_LEN());
1486                 break;
1487         case ENCRYPT_START:
1488                 encrypt_start(subpointer, SB_LEN());
1489                 break;
1490         case ENCRYPT_END:
1491                 encrypt_end();
1492                 break;
1493         case ENCRYPT_REQSTART:
1494                 encrypt_request_start(subpointer, SB_LEN());
1495                 break;
1496         case ENCRYPT_REQEND:
1497                 /*
1498                  * We can always send an REQEND so that we cannot
1499                  * get stuck encrypting.  We should only get this
1500                  * if we have been able to get in the correct mode
1501                  * anyhow.
1502                  */
1503                 encrypt_request_end();
1504                 break;
1505         case ENCRYPT_ENC_KEYID:
1506                 encrypt_enc_keyid(subpointer, SB_LEN());
1507                 break;
1508         case ENCRYPT_DEC_KEYID:
1509                 encrypt_dec_keyid(subpointer, SB_LEN());
1510                 break;
1511         default:
1512                 break;
1513         }
1514         break;
1515 #endif  /* ENCRYPTION */
1516
1517     default:
1518         break;
1519     }  /* end of switch */
1520
1521 }  /* end of suboption */
1522
1523         void
1524 doclientstat()
1525 {
1526         clientstat(TELOPT_LINEMODE, WILL, 0);
1527 }
1528
1529 #define ADD(c)   *ncp++ = c
1530 #define ADD_DATA(c) { *ncp++ = c; if (c == SE || c == IAC) *ncp++ = c; }
1531         void
1532 send_status()
1533 {
1534         unsigned char statusbuf[256];
1535         register unsigned char *ncp;
1536         register unsigned char i;
1537
1538         ncp = statusbuf;
1539
1540         netflush();     /* get rid of anything waiting to go out */
1541
1542         ADD(IAC);
1543         ADD(SB);
1544         ADD(TELOPT_STATUS);
1545         ADD(TELQUAL_IS);
1546
1547         /*
1548          * We check the want_state rather than the current state,
1549          * because if we received a DO/WILL for an option that we
1550          * don't support, and the other side didn't send a DONT/WONT
1551          * in response to our WONT/DONT, then the "state" will be
1552          * WILL/DO, and the "want_state" will be WONT/DONT.  We
1553          * need to go by the latter.
1554          */
1555         for (i = 0; i < (unsigned char)NTELOPTS; i++) {
1556                 if (my_want_state_is_will(i)) {
1557                         ADD(WILL);
1558                         ADD_DATA(i);
1559                 }
1560                 if (his_want_state_is_will(i)) {
1561                         ADD(DO);
1562                         ADD_DATA(i);
1563                 }
1564         }
1565
1566         if (his_want_state_is_will(TELOPT_LFLOW)) {
1567                 ADD(SB);
1568                 ADD(TELOPT_LFLOW);
1569                 if (flowmode) {
1570                         ADD(LFLOW_ON);
1571                 } else {
1572                         ADD(LFLOW_OFF);
1573                 }
1574                 ADD(SE);
1575
1576                 if (restartany >= 0) {
1577                         ADD(SB);
1578                         ADD(TELOPT_LFLOW);
1579                         if (restartany) {
1580                                 ADD(LFLOW_RESTART_ANY);
1581                         } else {
1582                                 ADD(LFLOW_RESTART_XON);
1583                         }
1584                         ADD(SE);
1585                 }
1586         }
1587
1588 #ifdef  LINEMODE
1589         if (his_want_state_is_will(TELOPT_LINEMODE)) {
1590                 unsigned char *cp, *cpe;
1591                 int len;
1592
1593                 ADD(SB);
1594                 ADD(TELOPT_LINEMODE);
1595                 ADD(LM_MODE);
1596                 ADD_DATA(editmode);
1597                 ADD(SE);
1598
1599                 ADD(SB);
1600                 ADD(TELOPT_LINEMODE);
1601                 ADD(LM_SLC);
1602                 start_slc(0);
1603                 send_slc();
1604                 len = end_slc(&cp);
1605                 for (cpe = cp + len; cp < cpe; cp++)
1606                         ADD_DATA(*cp);
1607                 ADD(SE);
1608         }
1609 #endif  /* LINEMODE */
1610
1611         ADD(IAC);
1612         ADD(SE);
1613
1614         writenet(statusbuf, ncp - statusbuf);
1615         netflush();     /* Send it on its way */
1616
1617         DIAG(TD_OPTIONS,
1618                 {printsub('>', statusbuf, ncp - statusbuf); netflush();});
1619 }