contrib/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. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #if 0
  31 #ifndef lint
  32 static const char sccsid[] = "@(#)state.c       8.5 (Berkeley) 5/30/95";
  33 #endif
  34 #endif
  35 #include <sys/cdefs.h>
  36 __FBSDID("$FreeBSD$");
  37
  38 #include <stdarg.h>
  39 #include "telnetd.h"
  40 #ifdef  AUTHENTICATION
  41 #include <libtelnet/auth.h>
  42 #endif
  43 #ifdef  ENCRYPTION
  44 #include <libtelnet/encrypt.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 static void doclientstat(void);
  89
  90 void
  91 telrcv(void)
  92 {
  93         int c;
  94         static int state = TS_DATA;
  95
  96         while (ncc > 0) {
  97                 if ((&ptyobuf[BUFSIZ] - pfrontp) < 2)
  98                         break;
  99                 c = *netip++ & 0377, ncc--;
 100 #ifdef  ENCRYPTION
 101                 if (decrypt_input)
 102                         c = (*decrypt_input)(c);
 103 #endif  /* ENCRYPTION */
 104                 switch (state) {
 105
 106                 case TS_CR:
 107                         state = TS_DATA;
 108                         /* Strip off \n or \0 after a \r */
 109                         if ((c == 0) || (c == '\n')) {
 110                                 break;
 111                         }
 112                         /* FALLTHROUGH */
 113
 114                 case TS_DATA:
 115                         if (c == IAC) {
 116                                 state = TS_IAC;
 117                                 break;
 118                         }
 119                         /*
 120                          * We now map \r\n ==> \r for pragmatic reasons.
 121                          * Many client implementations send \r\n when
 122                          * the user hits the CarriageReturn key.
 123                          *
 124                          * We USED to map \r\n ==> \n, since \r\n says
 125                          * that we want to be in column 1 of the next
 126                          * printable line, and \n is the standard
 127                          * unix way of saying that (\r is only good
 128                          * if CRMOD is set, which it normally is).
 129                          */
 130                         if ((c == '\r') && his_state_is_wont(TELOPT_BINARY)) {
 131                                 int nc = *netip;
 132 #ifdef  ENCRYPTION
 133                                 if (decrypt_input)
 134                                         nc = (*decrypt_input)(nc & 0xff);
 135 #endif  /* ENCRYPTION */
 136 #ifdef  LINEMODE
 137                                 /*
 138                                  * If we are operating in linemode,
 139                                  * convert to local end-of-line.
 140                                  */
 141                                 if (linemode && (ncc > 0) && (('\n' == nc) ||
 142                                          ((0 == nc) && tty_iscrnl())) ) {
 143                                         netip++; ncc--;
 144                                         c = '\n';
 145                                 } else
 146 #endif
 147                                 {
 148 #ifdef  ENCRYPTION
 149                                         if (decrypt_input)
 150                                                 (void)(*decrypt_input)(-1);
 151 #endif  /* ENCRYPTION */
 152                                         state = TS_CR;
 153                                 }
 154                         }
 155                         *pfrontp++ = c;
 156                         break;
 157
 158                 case TS_IAC:
 159 gotiac:                 switch (c) {
 160
 161                         /*
 162                          * Send the process on the pty side an
 163                          * interrupt.  Do this with a NULL or
 164                          * interrupt char; depending on the tty mode.
 165                          */
 166                         case IP:
 167                                 DIAG(TD_OPTIONS,
 168                                         printoption("td: recv IAC", c));
 169                                 interrupt();
 170                                 break;
 171
 172                         case BREAK:
 173                                 DIAG(TD_OPTIONS,
 174                                         printoption("td: recv IAC", c));
 175                                 sendbrk();
 176                                 break;
 177
 178                         /*
 179                          * Are You There?
 180                          */
 181                         case AYT:
 182                                 DIAG(TD_OPTIONS,
 183                                         printoption("td: recv IAC", c));
 184                                 recv_ayt();
 185                                 break;
 186
 187                         /*
 188                          * Abort Output
 189                          */
 190                         case AO:
 191                             {
 192                                 DIAG(TD_OPTIONS,
 193                                         printoption("td: recv IAC", c));
 194                                 ptyflush();     /* half-hearted */
 195                                 init_termbuf();
 196
 197                                 if (slctab[SLC_AO].sptr &&
 198                                     *slctab[SLC_AO].sptr != (cc_t)(_POSIX_VDISABLE)) {
 199                                     *pfrontp++ =
 200                                         (unsigned char)*slctab[SLC_AO].sptr;
 201                                 }
 202
 203                                 netclear();     /* clear buffer back */
 204                                 output_data("%c%c", IAC, DM);
 205                                 neturg = nfrontp-1; /* off by one XXX */
 206                                 DIAG(TD_OPTIONS,
 207                                         printoption("td: send IAC", DM));
 208                                 break;
 209                             }
 210
 211                         /*
 212                          * Erase Character and
 213                          * Erase Line
 214                          */
 215                         case EC:
 216                         case EL:
 217                             {
 218                                 cc_t ch;
 219
 220                                 DIAG(TD_OPTIONS,
 221                                         printoption("td: recv IAC", c));
 222                                 ptyflush();     /* half-hearted */
 223                                 init_termbuf();
 224                                 if (c == EC)
 225                                         ch = *slctab[SLC_EC].sptr;
 226                                 else
 227                                         ch = *slctab[SLC_EL].sptr;
 228                                 if (ch != (cc_t)(_POSIX_VDISABLE))
 229                                         *pfrontp++ = (unsigned char)ch;
 230                                 break;
 231                             }
 232
 233                         /*
 234                          * Check for urgent data...
 235                          */
 236                         case DM:
 237                                 DIAG(TD_OPTIONS,
 238                                         printoption("td: recv IAC", c));
 239                                 SYNCHing = stilloob(net);
 240                                 settimer(gotDM);
 241                                 break;
 242
 243
 244                         /*
 245                          * Begin option subnegotiation...
 246                          */
 247                         case SB:
 248                                 state = TS_SB;
 249                                 SB_CLEAR();
 250                                 continue;
 251
 252                         case WILL:
 253                                 state = TS_WILL;
 254                                 continue;
 255
 256                         case WONT:
 257                                 state = TS_WONT;
 258                                 continue;
 259
 260                         case DO:
 261                                 state = TS_DO;
 262                                 continue;
 263
 264                         case DONT:
 265                                 state = TS_DONT;
 266                                 continue;
 267                         case EOR:
 268                                 if (his_state_is_will(TELOPT_EOR))
 269                                         doeof();
 270                                 break;
 271
 272                         /*
 273                          * Handle RFC 10xx Telnet linemode option additions
 274                          * to command stream (EOF, SUSP, ABORT).
 275                          */
 276                         case xEOF:
 277                                 doeof();
 278                                 break;
 279
 280                         case SUSP:
 281                                 sendsusp();
 282                                 break;
 283
 284                         case ABORT:
 285                                 sendbrk();
 286                                 break;
 287
 288                         case IAC:
 289                                 *pfrontp++ = c;
 290                                 break;
 291                         }
 292                         state = TS_DATA;
 293                         break;
 294
 295                 case TS_SB:
 296                         if (c == IAC) {
 297                                 state = TS_SE;
 298                         } else {
 299                                 SB_ACCUM(c);
 300                         }
 301                         break;
 302
 303                 case TS_SE:
 304                         if (c != SE) {
 305                                 if (c != IAC) {
 306                                         /*
 307                                          * bad form of suboption negotiation.
 308                                          * handle it in such a way as to avoid
 309                                          * damage to local state.  Parse
 310                                          * suboption buffer found so far,
 311                                          * then treat remaining stream as
 312                                          * another command sequence.
 313                                          */
 314
 315                                         /* for DIAGNOSTICS */
 316                                         SB_ACCUM(IAC);
 317                                         SB_ACCUM(c);
 318                                         subpointer -= 2;
 319
 320                                         SB_TERM();
 321                                         suboption();
 322                                         state = TS_IAC;
 323                                         goto gotiac;
 324                                 }
 325                                 SB_ACCUM(c);
 326                                 state = TS_SB;
 327                         } else {
 328                                 /* for DIAGNOSTICS */
 329                                 SB_ACCUM(IAC);
 330                                 SB_ACCUM(SE);
 331                                 subpointer -= 2;
 332
 333                                 SB_TERM();
 334                                 suboption();    /* handle sub-option */
 335                                 state = TS_DATA;
 336                         }
 337                         break;
 338
 339                 case TS_WILL:
 340                         willoption(c);
 341                         state = TS_DATA;
 342                         continue;
 343
 344                 case TS_WONT:
 345                         wontoption(c);
 346                         state = TS_DATA;
 347                         continue;
 348
 349                 case TS_DO:
 350                         dooption(c);
 351                         state = TS_DATA;
 352                         continue;
 353
 354                 case TS_DONT:
 355                         dontoption(c);
 356                         state = TS_DATA;
 357                         continue;
 358
 359                 default:
 360                         syslog(LOG_ERR, "panic state=%d", state);
 361                         printf("telnetd: panic state=%d\n", state);
 362                         exit(1);
 363                 }
 364         }
 365 }  /* end of telrcv */
 366
 367 /*
 368  * The will/wont/do/dont state machines are based on Dave Borman's
 369  * Telnet option processing state machine.
 370  *
 371  * These correspond to the following states:
 372  *      my_state = the last negotiated state
 373  *      want_state = what I want the state to go to
 374  *      want_resp = how many requests I have sent
 375  * All state defaults are negative, and resp defaults to 0.
 376  *
 377  * When initiating a request to change state to new_state:
 378  *
 379  * if ((want_resp == 0 && new_state == my_state) || want_state == new_state) {
 380  *      do nothing;
 381  * } else {
 382  *      want_state = new_state;
 383  *      send new_state;
 384  *      want_resp++;
 385  * }
 386  *
 387  * When receiving new_state:
 388  *
 389  * if (want_resp) {
 390  *      want_resp--;
 391  *      if (want_resp && (new_state == my_state))
 392  *              want_resp--;
 393  * }
 394  * if ((want_resp == 0) && (new_state != want_state)) {
 395  *      if (ok_to_switch_to new_state)
 396  *              want_state = new_state;
 397  *      else
 398  *              want_resp++;
 399  *      send want_state;
 400  * }
 401  * my_state = new_state;
 402  *
 403  * Note that new_state is implied in these functions by the function itself.
 404  * will and do imply positive new_state, wont and dont imply negative.
 405  *
 406  * Finally, there is one catch.  If we send a negative response to a
 407  * positive request, my_state will be the positive while want_state will
 408  * remain negative.  my_state will revert to negative when the negative
 409  * acknowlegment arrives from the peer.  Thus, my_state generally tells
 410  * us not only the last negotiated state, but also tells us what the peer
 411  * wants to be doing as well.  It is important to understand this difference
 412  * as we may wish to be processing data streams based on our desired state
 413  * (want_state) or based on what the peer thinks the state is (my_state).
 414  *
 415  * This all works fine because if the peer sends a positive request, the data
 416  * that we receive prior to negative acknowlegment will probably be affected
 417  * by the positive state, and we can process it as such (if we can; if we
 418  * can't then it really doesn't matter).  If it is that important, then the
 419  * peer probably should be buffering until this option state negotiation
 420  * is complete.
 421  *
 422  */
 423 void
 424 send_do(int option, int init)
 425 {
 426         if (init) {
 427                 if ((do_dont_resp[option] == 0 && his_state_is_will(option)) ||
 428                     his_want_state_is_will(option))
 429                         return;
 430                 /*
 431                  * Special case for TELOPT_TM:  We send a DO, but pretend
 432                  * that we sent a DONT, so that we can send more DOs if
 433                  * we want to.
 434                  */
 435                 if (option == TELOPT_TM)
 436                         set_his_want_state_wont(option);
 437                 else
 438                         set_his_want_state_will(option);
 439                 do_dont_resp[option]++;
 440         }
 441         output_data((const char *)doopt, option);
 442
 443         DIAG(TD_OPTIONS, printoption("td: send do", option));
 444 }
 445
 446 void
 447 willoption(int option)
 448 {
 449         int changeok = 0;
 450         void (*func)(void) = 0;
 451
 452         /*
 453          * process input from peer.
 454          */
 455
 456         DIAG(TD_OPTIONS, printoption("td: recv will", option));
 457
 458         if (do_dont_resp[option]) {
 459                 do_dont_resp[option]--;
 460                 if (do_dont_resp[option] && his_state_is_will(option))
 461                         do_dont_resp[option]--;
 462         }
 463         if (do_dont_resp[option] == 0) {
 464             if (his_want_state_is_wont(option)) {
 465                 switch (option) {
 466
 467                 case TELOPT_BINARY:
 468                         init_termbuf();
 469                         tty_binaryin(1);
 470                         set_termbuf();
 471                         changeok++;
 472                         break;
 473
 474                 case TELOPT_ECHO:
 475                         /*
 476                          * See comments below for more info.
 477                          */
 478                         not42 = 0;      /* looks like a 4.2 system */
 479                         break;
 480
 481                 case TELOPT_TM:
 482 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
 483                         /*
 484                          * This telnetd implementation does not really
 485                          * support timing marks, it just uses them to
 486                          * support the kludge linemode stuff.  If we
 487                          * receive a will or wont TM in response to our
 488                          * do TM request that may have been sent to
 489                          * determine kludge linemode support, process
 490                          * it, otherwise TM should get a negative
 491                          * response back.
 492                          */
 493                         /*
 494                          * Handle the linemode kludge stuff.
 495                          * If we are not currently supporting any
 496                          * linemode at all, then we assume that this
 497                          * is the client telling us to use kludge
 498                          * linemode in response to our query.  Set the
 499                          * linemode type that is to be supported, note
 500                          * that the client wishes to use linemode, and
 501                          * eat the will TM as though it never arrived.
 502                          */
 503                         if (lmodetype < KLUDGE_LINEMODE) {
 504                                 lmodetype = KLUDGE_LINEMODE;
 505                                 clientstat(TELOPT_LINEMODE, WILL, 0);
 506                                 send_wont(TELOPT_SGA, 1);
 507                         } else if (lmodetype == NO_AUTOKLUDGE) {
 508                                 lmodetype = KLUDGE_OK;
 509                         }
 510 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
 511                         /*
 512                          * We never respond to a WILL TM, and
 513                          * we leave the state WONT.
 514                          */
 515                         return;
 516
 517                 case TELOPT_LFLOW:
 518                         /*
 519                          * If we are going to support flow control
 520                          * option, then don't worry peer that we can't
 521                          * change the flow control characters.
 522                          */
 523                         slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
 524                         slctab[SLC_XON].defset.flag |= SLC_DEFAULT;
 525                         slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
 526                         slctab[SLC_XOFF].defset.flag |= SLC_DEFAULT;
 527                 case TELOPT_TTYPE:
 528                 case TELOPT_SGA:
 529                 case TELOPT_NAWS:
 530                 case TELOPT_TSPEED:
 531                 case TELOPT_XDISPLOC:
 532                 case TELOPT_NEW_ENVIRON:
 533                 case TELOPT_OLD_ENVIRON:
 534                         changeok++;
 535                         break;
 536
 537 #ifdef  LINEMODE
 538                 case TELOPT_LINEMODE:
 539 # ifdef KLUDGELINEMODE
 540                         /*
 541                          * Note client's desire to use linemode.
 542                          */
 543                         lmodetype = REAL_LINEMODE;
 544 # endif /* KLUDGELINEMODE */
 545                         func = doclientstat;
 546                         changeok++;
 547                         break;
 548 #endif  /* LINEMODE */
 549
 550 #ifdef  AUTHENTICATION
 551                 case TELOPT_AUTHENTICATION:
 552                         if (auth_level >= 0) {
 553                                 func = auth_request;
 554                                 changeok++;
 555                         }
 556                         break;
 557 #endif
 558
 559 #ifdef  ENCRYPTION
 560                 case TELOPT_ENCRYPT:
 561                         func = encrypt_send_support;
 562                         changeok++;
 563                         break;
 564 #endif  /* ENCRYPTION */
 565
 566                 default:
 567                         break;
 568                 }
 569                 if (changeok) {
 570                         set_his_want_state_will(option);
 571                         send_do(option, 0);
 572                 } else {
 573                         do_dont_resp[option]++;
 574                         send_dont(option, 0);
 575                 }
 576             } else {
 577                 /*
 578                  * Option processing that should happen when
 579                  * we receive conformation of a change in
 580                  * state that we had requested.
 581                  */
 582                 switch (option) {
 583                 case TELOPT_ECHO:
 584                         not42 = 0;      /* looks like a 4.2 system */
 585                         /*
 586                          * Egads, he responded "WILL ECHO".  Turn
 587                          * it off right now!
 588                          */
 589                         send_dont(option, 1);
 590                         /*
 591                          * "WILL ECHO".  Kludge upon kludge!
 592                          * A 4.2 client is now echoing user input at
 593                          * the tty.  This is probably undesireable and
 594                          * it should be stopped.  The client will
 595                          * respond WONT TM to the DO TM that we send to
 596                          * check for kludge linemode.  When the WONT TM
 597                          * arrives, linemode will be turned off and a
 598                          * change propogated to the pty.  This change
 599                          * will cause us to process the new pty state
 600                          * in localstat(), which will notice that
 601                          * linemode is off and send a WILL ECHO
 602                          * so that we are properly in character mode and
 603                          * all is well.
 604                          */
 605                         break;
 606 #ifdef  LINEMODE
 607                 case TELOPT_LINEMODE:
 608 # ifdef KLUDGELINEMODE
 609                         /*
 610                          * Note client's desire to use linemode.
 611                          */
 612                         lmodetype = REAL_LINEMODE;
 613 # endif /* KLUDGELINEMODE */
 614                         func = doclientstat;
 615                         break;
 616 #endif  /* LINEMODE */
 617
 618 #ifdef  AUTHENTICATION
 619                 case TELOPT_AUTHENTICATION:
 620                         func = auth_request;
 621                         break;
 622 #endif
 623
 624 #ifdef  ENCRYPTION
 625                 case TELOPT_ENCRYPT:
 626                         func = encrypt_send_support;
 627                         break;
 628 #endif  /* ENCRYPTION */
 629                 case TELOPT_LFLOW:
 630                         func = flowstat;
 631                         break;
 632                 }
 633             }
 634         }
 635         set_his_state_will(option);
 636         if (func)
 637                 (*func)();
 638 }  /* end of willoption */
 639
 640 void
 641 send_dont(int option, int init)
 642 {
 643         if (init) {
 644                 if ((do_dont_resp[option] == 0 && his_state_is_wont(option)) ||
 645                     his_want_state_is_wont(option))
 646                         return;
 647                 set_his_want_state_wont(option);
 648                 do_dont_resp[option]++;
 649         }
 650         output_data((const char *)dont, option);
 651
 652         DIAG(TD_OPTIONS, printoption("td: send dont", option));
 653 }
 654
 655 void
 656 wontoption(int option)
 657 {
 658         /*
 659          * Process client input.
 660          */
 661
 662         DIAG(TD_OPTIONS, printoption("td: recv wont", option));
 663
 664         if (do_dont_resp[option]) {
 665                 do_dont_resp[option]--;
 666                 if (do_dont_resp[option] && his_state_is_wont(option))
 667                         do_dont_resp[option]--;
 668         }
 669         if (do_dont_resp[option] == 0) {
 670             if (his_want_state_is_will(option)) {
 671                 /* it is always ok to change to negative state */
 672                 switch (option) {
 673                 case TELOPT_ECHO:
 674                         not42 = 1; /* doesn't seem to be a 4.2 system */
 675                         break;
 676
 677                 case TELOPT_BINARY:
 678                         init_termbuf();
 679                         tty_binaryin(0);
 680                         set_termbuf();
 681                         break;
 682
 683 #ifdef  LINEMODE
 684                 case TELOPT_LINEMODE:
 685 # ifdef KLUDGELINEMODE
 686                         /*
 687                          * If real linemode is supported, then client is
 688                          * asking to turn linemode off.
 689                          */
 690                         if (lmodetype != REAL_LINEMODE)
 691                                 break;
 692                         lmodetype = KLUDGE_LINEMODE;
 693 # endif /* KLUDGELINEMODE */
 694                         clientstat(TELOPT_LINEMODE, WONT, 0);
 695                         break;
 696 #endif  /* LINEMODE */
 697
 698                 case TELOPT_TM:
 699                         /*
 700                          * If we get a WONT TM, and had sent a DO TM,
 701                          * don't respond with a DONT TM, just leave it
 702                          * as is.  Short circut the state machine to
 703                          * achive this.
 704                          */
 705                         set_his_want_state_wont(TELOPT_TM);
 706                         return;
 707
 708                 case TELOPT_LFLOW:
 709                         /*
 710                          * If we are not going to support flow control
 711                          * option, then let peer know that we can't
 712                          * change the flow control characters.
 713                          */
 714                         slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
 715                         slctab[SLC_XON].defset.flag |= SLC_CANTCHANGE;
 716                         slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
 717                         slctab[SLC_XOFF].defset.flag |= SLC_CANTCHANGE;
 718                         break;
 719
 720 #ifdef  AUTHENTICATION
 721                 case TELOPT_AUTHENTICATION:
 722                         auth_finished(0, AUTH_REJECT);
 723                         break;
 724 #endif
 725
 726                 /*
 727                  * For options that we might spin waiting for
 728                  * sub-negotiation, if the client turns off the
 729                  * option rather than responding to the request,
 730                  * we have to treat it here as if we got a response
 731                  * to the sub-negotiation, (by updating the timers)
 732                  * so that we'll break out of the loop.
 733                  */
 734                 case TELOPT_TTYPE:
 735                         settimer(ttypesubopt);
 736                         break;
 737
 738                 case TELOPT_TSPEED:
 739                         settimer(tspeedsubopt);
 740                         break;
 741
 742                 case TELOPT_XDISPLOC:
 743                         settimer(xdisplocsubopt);
 744                         break;
 745
 746                 case TELOPT_OLD_ENVIRON:
 747                         settimer(oenvironsubopt);
 748                         break;
 749
 750                 case TELOPT_NEW_ENVIRON:
 751                         settimer(environsubopt);
 752                         break;
 753
 754                 default:
 755                         break;
 756                 }
 757                 set_his_want_state_wont(option);
 758                 if (his_state_is_will(option))
 759                         send_dont(option, 0);
 760             } else {
 761                 switch (option) {
 762                 case TELOPT_TM:
 763 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
 764                         if (lmodetype < NO_AUTOKLUDGE) {
 765                                 lmodetype = NO_LINEMODE;
 766                                 clientstat(TELOPT_LINEMODE, WONT, 0);
 767                                 send_will(TELOPT_SGA, 1);
 768                                 send_will(TELOPT_ECHO, 1);
 769                         }
 770 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
 771                         break;
 772
 773 #ifdef AUTHENTICATION
 774                 case TELOPT_AUTHENTICATION:
 775                         auth_finished(0, AUTH_REJECT);
 776                         break;
 777 #endif
 778                 default:
 779                         break;
 780                 }
 781             }
 782         }
 783         set_his_state_wont(option);
 784
 785 }  /* end of wontoption */
 786
 787 void
 788 send_will(int option, int init)
 789 {
 790         if (init) {
 791                 if ((will_wont_resp[option] == 0 && my_state_is_will(option))||
 792                     my_want_state_is_will(option))
 793                         return;
 794                 set_my_want_state_will(option);
 795                 will_wont_resp[option]++;
 796         }
 797         output_data((const char *)will, option);
 798
 799         DIAG(TD_OPTIONS, printoption("td: send will", option));
 800 }
 801
 802 #if     !defined(LINEMODE) || !defined(KLUDGELINEMODE)
 803 /*
 804  * When we get a DONT SGA, we will try once to turn it
 805  * back on.  If the other side responds DONT SGA, we
 806  * leave it at that.  This is so that when we talk to
 807  * clients that understand KLUDGELINEMODE but not LINEMODE,
 808  * we'll keep them in char-at-a-time mode.
 809  */
 810 int turn_on_sga = 0;
 811 #endif
 812
 813 void
 814 dooption(int option)
 815 {
 816         int changeok = 0;
 817
 818         /*
 819          * Process client input.
 820          */
 821
 822         DIAG(TD_OPTIONS, printoption("td: recv do", option));
 823
 824         if (will_wont_resp[option]) {
 825                 will_wont_resp[option]--;
 826                 if (will_wont_resp[option] && my_state_is_will(option))
 827                         will_wont_resp[option]--;
 828         }
 829         if ((will_wont_resp[option] == 0) && (my_want_state_is_wont(option))) {
 830                 switch (option) {
 831                 case TELOPT_ECHO:
 832 #ifdef  LINEMODE
 833 # ifdef KLUDGELINEMODE
 834                         if (lmodetype == NO_LINEMODE)
 835 # else
 836                         if (his_state_is_wont(TELOPT_LINEMODE))
 837 # endif
 838 #endif
 839                         {
 840                                 init_termbuf();
 841                                 tty_setecho(1);
 842                                 set_termbuf();
 843                         }
 844                         changeok++;
 845                         break;
 846
 847                 case TELOPT_BINARY:
 848                         init_termbuf();
 849                         tty_binaryout(1);
 850                         set_termbuf();
 851                         changeok++;
 852                         break;
 853
 854                 case TELOPT_SGA:
 855 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
 856                         /*
 857                          * If kludge linemode is in use, then we must
 858                          * process an incoming do SGA for linemode
 859                          * purposes.
 860                          */
 861                         if (lmodetype == KLUDGE_LINEMODE) {
 862                                 /*
 863                                  * Receipt of "do SGA" in kludge
 864                                  * linemode is the peer asking us to
 865                                  * turn off linemode.  Make note of
 866                                  * the request.
 867                                  */
 868                                 clientstat(TELOPT_LINEMODE, WONT, 0);
 869                                 /*
 870                                  * If linemode did not get turned off
 871                                  * then don't tell peer that we did.
 872                                  * Breaking here forces a wont SGA to
 873                                  * be returned.
 874                                  */
 875                                 if (linemode)
 876                                         break;
 877                         }
 878 #else
 879                         turn_on_sga = 0;
 880 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
 881                         changeok++;
 882                         break;
 883
 884                 case TELOPT_STATUS:
 885                         changeok++;
 886                         break;
 887
 888                 case TELOPT_TM:
 889                         /*
 890                          * Special case for TM.  We send a WILL, but
 891                          * pretend we sent a WONT.
 892                          */
 893                         send_will(option, 0);
 894                         set_my_want_state_wont(option);
 895                         set_my_state_wont(option);
 896                         return;
 897
 898                 case TELOPT_LOGOUT:
 899                         /*
 900                          * When we get a LOGOUT option, respond
 901                          * with a WILL LOGOUT, make sure that
 902                          * it gets written out to the network,
 903                          * and then just go away...
 904                          */
 905                         set_my_want_state_will(TELOPT_LOGOUT);
 906                         send_will(TELOPT_LOGOUT, 0);
 907                         set_my_state_will(TELOPT_LOGOUT);
 908                         (void)netflush();
 909                         cleanup(0);
 910                         /* NOT REACHED */
 911                         break;
 912
 913 #ifdef  ENCRYPTION
 914                 case TELOPT_ENCRYPT:
 915                         changeok++;
 916                         break;
 917 #endif  /* ENCRYPTION */
 918                 case TELOPT_LINEMODE:
 919                 case TELOPT_TTYPE:
 920                 case TELOPT_NAWS:
 921                 case TELOPT_TSPEED:
 922                 case TELOPT_LFLOW:
 923                 case TELOPT_XDISPLOC:
 924 #ifdef  TELOPT_ENVIRON
 925                 case TELOPT_NEW_ENVIRON:
 926 #endif
 927                 case TELOPT_OLD_ENVIRON:
 928                 default:
 929                         break;
 930                 }
 931                 if (changeok) {
 932                         set_my_want_state_will(option);
 933                         send_will(option, 0);
 934                 } else {
 935                         will_wont_resp[option]++;
 936                         send_wont(option, 0);
 937                 }
 938         }
 939         set_my_state_will(option);
 940
 941 }  /* end of dooption */
 942
 943 void
 944 send_wont(int option, int init)
 945 {
 946         if (init) {
 947                 if ((will_wont_resp[option] == 0 && my_state_is_wont(option)) ||
 948                     my_want_state_is_wont(option))
 949                         return;
 950                 set_my_want_state_wont(option);
 951                 will_wont_resp[option]++;
 952         }
 953         output_data((const char *)wont, option);
 954
 955         DIAG(TD_OPTIONS, printoption("td: send wont", option));
 956 }
 957
 958 void
 959 dontoption(int option)
 960 {
 961         /*
 962          * Process client input.
 963          */
 964
 965
 966         DIAG(TD_OPTIONS, printoption("td: recv dont", option));
 967
 968         if (will_wont_resp[option]) {
 969                 will_wont_resp[option]--;
 970                 if (will_wont_resp[option] && my_state_is_wont(option))
 971                         will_wont_resp[option]--;
 972         }
 973         if ((will_wont_resp[option] == 0) && (my_want_state_is_will(option))) {
 974                 switch (option) {
 975                 case TELOPT_BINARY:
 976                         init_termbuf();
 977                         tty_binaryout(0);
 978                         set_termbuf();
 979                         break;
 980
 981                 case TELOPT_ECHO:       /* we should stop echoing */
 982 #ifdef  LINEMODE
 983 # ifdef KLUDGELINEMODE
 984                         if ((lmodetype != REAL_LINEMODE) &&
 985                             (lmodetype != KLUDGE_LINEMODE))
 986 # else
 987                         if (his_state_is_wont(TELOPT_LINEMODE))
 988 # endif
 989 #endif
 990                         {
 991                                 init_termbuf();
 992                                 tty_setecho(0);
 993                                 set_termbuf();
 994                         }
 995                         break;
 996
 997                 case TELOPT_SGA:
 998 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
 999                         /*
1000                          * If kludge linemode is in use, then we
1001                          * must process an incoming do SGA for
1002                          * linemode purposes.
1003                          */
1004                         if ((lmodetype == KLUDGE_LINEMODE) ||
1005                             (lmodetype == KLUDGE_OK)) {
1006                                 /*
1007                                  * The client is asking us to turn
1008                                  * linemode on.
1009                                  */
1010                                 lmodetype = KLUDGE_LINEMODE;
1011                                 clientstat(TELOPT_LINEMODE, WILL, 0);
1012                                 /*
1013                                  * If we did not turn line mode on,
1014                                  * then what do we say?  Will SGA?
1015                                  * This violates design of telnet.
1016                                  * Gross.  Very Gross.
1017                                  */
1018                         }
1019                         break;
1020 #else
1021                         set_my_want_state_wont(option);
1022                         if (my_state_is_will(option))
1023                                 send_wont(option, 0);
1024                         set_my_state_wont(option);
1025                         if (turn_on_sga ^= 1)
1026                                 send_will(option, 1);
1027                         return;
1028 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
1029
1030                 default:
1031                         break;
1032                 }
1033
1034                 set_my_want_state_wont(option);
1035                 if (my_state_is_will(option))
1036                         send_wont(option, 0);
1037         }
1038         set_my_state_wont(option);
1039
1040 }  /* end of dontoption */
1041
1042 #ifdef  ENV_HACK
1043 int env_ovar = -1;
1044 int env_ovalue = -1;
1045 #else   /* ENV_HACK */
1046 # define env_ovar OLD_ENV_VAR
1047 # define env_ovalue OLD_ENV_VALUE
1048 #endif  /* ENV_HACK */
1049
1050 /*
1051  * suboption()
1052  *
1053  *      Look at the sub-option buffer, and try to be helpful to the other
1054  * side.
1055  *
1056  *      Currently we recognize:
1057  *
1058  *      Terminal type is
1059  *      Linemode
1060  *      Window size
1061  *      Terminal speed
1062  */
1063 void
1064 suboption(void)
1065 {
1066     int subchar;
1067
1068     DIAG(TD_OPTIONS, {netflush(); printsub('<', subpointer, SB_LEN()+2);});
1069
1070     subchar = SB_GET();
1071     switch (subchar) {
1072     case TELOPT_TSPEED: {
1073         int xspeed, rspeed;
1074
1075         if (his_state_is_wont(TELOPT_TSPEED))   /* Ignore if option disabled */
1076                 break;
1077
1078         settimer(tspeedsubopt);
1079
1080         if (SB_EOF() || SB_GET() != TELQUAL_IS)
1081                 return;
1082
1083         xspeed = atoi((char *)subpointer);
1084
1085         while (SB_GET() != ',' && !SB_EOF());
1086         if (SB_EOF())
1087                 return;
1088
1089         rspeed = atoi((char *)subpointer);
1090         clientstat(TELOPT_TSPEED, xspeed, rspeed);
1091
1092         break;
1093
1094     }  /* end of case TELOPT_TSPEED */
1095
1096     case TELOPT_TTYPE: {                /* Yaaaay! */
1097         static char terminalname[41];
1098
1099         if (his_state_is_wont(TELOPT_TTYPE))    /* Ignore if option disabled */
1100                 break;
1101         settimer(ttypesubopt);
1102
1103         if (SB_EOF() || SB_GET() != TELQUAL_IS) {
1104             return;             /* ??? XXX but, this is the most robust */
1105         }
1106
1107         terminaltype = terminalname;
1108
1109         while ((terminaltype < (terminalname + sizeof terminalname-1)) &&
1110                                                                     !SB_EOF()) {
1111             int c;
1112
1113             c = SB_GET();
1114             if (isupper(c)) {
1115                 c = tolower(c);
1116             }
1117             *terminaltype++ = c;    /* accumulate name */
1118         }
1119         *terminaltype = 0;
1120         terminaltype = terminalname;
1121         break;
1122     }  /* end of case TELOPT_TTYPE */
1123
1124     case TELOPT_NAWS: {
1125         int xwinsize, ywinsize;
1126
1127         if (his_state_is_wont(TELOPT_NAWS))     /* Ignore if option disabled */
1128                 break;
1129
1130         if (SB_EOF())
1131                 return;
1132         xwinsize = SB_GET() << 8;
1133         if (SB_EOF())
1134                 return;
1135         xwinsize |= SB_GET();
1136         if (SB_EOF())
1137                 return;
1138         ywinsize = SB_GET() << 8;
1139         if (SB_EOF())
1140                 return;
1141         ywinsize |= SB_GET();
1142         clientstat(TELOPT_NAWS, xwinsize, ywinsize);
1143
1144         break;
1145
1146     }  /* end of case TELOPT_NAWS */
1147
1148 #ifdef  LINEMODE
1149     case TELOPT_LINEMODE: {
1150         int request;
1151
1152         if (his_state_is_wont(TELOPT_LINEMODE)) /* Ignore if option disabled */
1153                 break;
1154         /*
1155          * Process linemode suboptions.
1156          */
1157         if (SB_EOF())
1158             break;              /* garbage was sent */
1159         request = SB_GET();     /* get will/wont */
1160
1161         if (SB_EOF())
1162             break;              /* another garbage check */
1163
1164         if (request == LM_SLC) {  /* SLC is not preceeded by WILL or WONT */
1165                 /*
1166                  * Process suboption buffer of slc's
1167                  */
1168                 start_slc(1);
1169                 do_opt_slc(subpointer, subend - subpointer);
1170                 (void) end_slc(0);
1171                 break;
1172         } else if (request == LM_MODE) {
1173                 if (SB_EOF())
1174                     return;
1175                 useeditmode = SB_GET();  /* get mode flag */
1176                 clientstat(LM_MODE, 0, 0);
1177                 break;
1178         }
1179
1180         if (SB_EOF())
1181             break;
1182         switch (SB_GET()) {  /* what suboption? */
1183         case LM_FORWARDMASK:
1184                 /*
1185                  * According to spec, only server can send request for
1186                  * forwardmask, and client can only return a positive response.
1187                  * So don't worry about it.
1188                  */
1189
1190         default:
1191                 break;
1192         }
1193         break;
1194     }  /* end of case TELOPT_LINEMODE */
1195 #endif
1196     case TELOPT_STATUS: {
1197         int mode;
1198
1199         if (SB_EOF())
1200             break;
1201         mode = SB_GET();
1202         switch (mode) {
1203         case TELQUAL_SEND:
1204             if (my_state_is_will(TELOPT_STATUS))
1205                 send_status();
1206             break;
1207
1208         case TELQUAL_IS:
1209             break;
1210
1211         default:
1212             break;
1213         }
1214         break;
1215     }  /* end of case TELOPT_STATUS */
1216
1217     case TELOPT_XDISPLOC: {
1218         if (SB_EOF() || SB_GET() != TELQUAL_IS)
1219                 return;
1220         settimer(xdisplocsubopt);
1221         subpointer[SB_LEN()] = '\0';
1222         (void)setenv("DISPLAY", (char *)subpointer, 1);
1223         break;
1224     }  /* end of case TELOPT_XDISPLOC */
1225
1226 #ifdef  TELOPT_NEW_ENVIRON
1227     case TELOPT_NEW_ENVIRON:
1228 #endif
1229     case TELOPT_OLD_ENVIRON: {
1230         int c;
1231         char *cp, *varp, *valp;
1232
1233         if (SB_EOF())
1234                 return;
1235         c = SB_GET();
1236         if (c == TELQUAL_IS) {
1237                 if (subchar == TELOPT_OLD_ENVIRON)
1238                         settimer(oenvironsubopt);
1239                 else
1240                         settimer(environsubopt);
1241         } else if (c != TELQUAL_INFO) {
1242                 return;
1243         }
1244
1245 #ifdef  TELOPT_NEW_ENVIRON
1246         if (subchar == TELOPT_NEW_ENVIRON) {
1247             while (!SB_EOF()) {
1248                 c = SB_GET();
1249                 if ((c == NEW_ENV_VAR) || (c == ENV_USERVAR))
1250                         break;
1251             }
1252         } else
1253 #endif
1254         {
1255 #ifdef  ENV_HACK
1256             /*
1257              * We only want to do this if we haven't already decided
1258              * whether or not the other side has its VALUE and VAR
1259              * reversed.
1260              */
1261             if (env_ovar < 0) {
1262                 int last = -1;          /* invalid value */
1263                 int empty = 0;
1264                 int got_var = 0, got_value = 0, got_uservar = 0;
1265
1266                 /*
1267                  * The other side might have its VALUE and VAR values
1268                  * reversed.  To be interoperable, we need to determine
1269                  * which way it is.  If the first recognized character
1270                  * is a VAR or VALUE, then that will tell us what
1271                  * type of client it is.  If the fist recognized
1272                  * character is a USERVAR, then we continue scanning
1273                  * the suboption looking for two consecutive
1274                  * VAR or VALUE fields.  We should not get two
1275                  * consecutive VALUE fields, so finding two
1276                  * consecutive VALUE or VAR fields will tell us
1277                  * what the client is.
1278                  */
1279                 SB_SAVE();
1280                 while (!SB_EOF()) {
1281                         c = SB_GET();
1282                         switch(c) {
1283                         case OLD_ENV_VAR:
1284                                 if (last < 0 || last == OLD_ENV_VAR
1285                                     || (empty && (last == OLD_ENV_VALUE)))
1286                                         goto env_ovar_ok;
1287                                 got_var++;
1288                                 last = OLD_ENV_VAR;
1289                                 break;
1290                         case OLD_ENV_VALUE:
1291                                 if (last < 0 || last == OLD_ENV_VALUE
1292                                     || (empty && (last == OLD_ENV_VAR)))
1293                                         goto env_ovar_wrong;
1294                                 got_value++;
1295                                 last = OLD_ENV_VALUE;
1296                                 break;
1297                         case ENV_USERVAR:
1298                                 /* count strings of USERVAR as one */
1299                                 if (last != ENV_USERVAR)
1300                                         got_uservar++;
1301                                 if (empty) {
1302                                         if (last == OLD_ENV_VALUE)
1303                                                 goto env_ovar_ok;
1304                                         if (last == OLD_ENV_VAR)
1305                                                 goto env_ovar_wrong;
1306                                 }
1307                                 last = ENV_USERVAR;
1308                                 break;
1309                         case ENV_ESC:
1310                                 if (!SB_EOF())
1311                                         c = SB_GET();
1312                                 /* FALLTHROUGH */
1313                         default:
1314                                 empty = 0;
1315                                 continue;
1316                         }
1317                         empty = 1;
1318                 }
1319                 if (empty) {
1320                         if (last == OLD_ENV_VALUE)
1321                                 goto env_ovar_ok;
1322                         if (last == OLD_ENV_VAR)
1323                                 goto env_ovar_wrong;
1324                 }
1325                 /*
1326                  * Ok, the first thing was a USERVAR, and there
1327                  * are not two consecutive VAR or VALUE commands,
1328                  * and none of the VAR or VALUE commands are empty.
1329                  * If the client has sent us a well-formed option,
1330                  * then the number of VALUEs received should always
1331                  * be less than or equal to the number of VARs and
1332                  * USERVARs received.
1333                  *
1334                  * If we got exactly as many VALUEs as VARs and
1335                  * USERVARs, the client has the same definitions.
1336                  *
1337                  * If we got exactly as many VARs as VALUEs and
1338                  * USERVARS, the client has reversed definitions.
1339                  */
1340                 if (got_uservar + got_var == got_value) {
1341             env_ovar_ok:
1342                         env_ovar = OLD_ENV_VAR;
1343                         env_ovalue = OLD_ENV_VALUE;
1344                 } else if (got_uservar + got_value == got_var) {
1345             env_ovar_wrong:
1346                         env_ovar = OLD_ENV_VALUE;
1347                         env_ovalue = OLD_ENV_VAR;
1348                         DIAG(TD_OPTIONS,
1349                             output_data("ENVIRON VALUE and VAR are reversed!\r\n"));
1350
1351                 }
1352             }
1353             SB_RESTORE();
1354 #endif
1355
1356             while (!SB_EOF()) {
1357                 c = SB_GET();
1358                 if ((c == env_ovar) || (c == ENV_USERVAR))
1359                         break;
1360             }
1361         }
1362
1363         if (SB_EOF())
1364                 return;
1365
1366         cp = varp = (char *)subpointer;
1367         valp = 0;
1368
1369         while (!SB_EOF()) {
1370                 c = SB_GET();
1371                 if (subchar == TELOPT_OLD_ENVIRON) {
1372                         if (c == env_ovar)
1373                                 c = NEW_ENV_VAR;
1374                         else if (c == env_ovalue)
1375                                 c = NEW_ENV_VALUE;
1376                 }
1377                 switch (c) {
1378
1379                 case NEW_ENV_VALUE:
1380                         *cp = '\0';
1381                         cp = valp = (char *)subpointer;
1382                         break;
1383
1384                 case NEW_ENV_VAR:
1385                 case ENV_USERVAR:
1386                         *cp = '\0';
1387                         if (valp)
1388                                 (void)setenv(varp, valp, 1);
1389                         else
1390                                 unsetenv(varp);
1391                         cp = varp = (char *)subpointer;
1392                         valp = 0;
1393                         break;
1394
1395                 case ENV_ESC:
1396                         if (SB_EOF())
1397                                 break;
1398                         c = SB_GET();
1399                         /* FALLTHROUGH */
1400                 default:
1401                         *cp++ = c;
1402                         break;
1403                 }
1404         }
1405         *cp = '\0';
1406         if (valp)
1407                 (void)setenv(varp, valp, 1);
1408         else
1409                 unsetenv(varp);
1410         break;
1411     }  /* end of case TELOPT_NEW_ENVIRON */
1412 #ifdef  AUTHENTICATION
1413     case TELOPT_AUTHENTICATION:
1414         if (SB_EOF())
1415                 break;
1416         switch(SB_GET()) {
1417         case TELQUAL_SEND:
1418         case TELQUAL_REPLY:
1419                 /*
1420                  * These are sent by us and cannot be sent by
1421                  * the client.
1422                  */
1423                 break;
1424         case TELQUAL_IS:
1425                 auth_is(subpointer, SB_LEN());
1426                 break;
1427         case TELQUAL_NAME:
1428                 auth_name(subpointer, SB_LEN());
1429                 break;
1430         }
1431         break;
1432 #endif
1433 #ifdef  ENCRYPTION
1434     case TELOPT_ENCRYPT:
1435         if (SB_EOF())
1436                 break;
1437         switch(SB_GET()) {
1438         case ENCRYPT_SUPPORT:
1439                 encrypt_support(subpointer, SB_LEN());
1440                 break;
1441         case ENCRYPT_IS:
1442                 encrypt_is(subpointer, SB_LEN());
1443                 break;
1444         case ENCRYPT_REPLY:
1445                 encrypt_reply(subpointer, SB_LEN());
1446                 break;
1447         case ENCRYPT_START:
1448                 encrypt_start(subpointer, SB_LEN());
1449                 break;
1450         case ENCRYPT_END:
1451                 encrypt_end();
1452                 break;
1453         case ENCRYPT_REQSTART:
1454                 encrypt_request_start(subpointer, SB_LEN());
1455                 break;
1456         case ENCRYPT_REQEND:
1457                 /*
1458                  * We can always send an REQEND so that we cannot
1459                  * get stuck encrypting.  We should only get this
1460                  * if we have been able to get in the correct mode
1461                  * anyhow.
1462                  */
1463                 encrypt_request_end();
1464                 break;
1465         case ENCRYPT_ENC_KEYID:
1466                 encrypt_enc_keyid(subpointer, SB_LEN());
1467                 break;
1468         case ENCRYPT_DEC_KEYID:
1469                 encrypt_dec_keyid(subpointer, SB_LEN());
1470                 break;
1471         default:
1472                 break;
1473         }
1474         break;
1475 #endif  /* ENCRYPTION */
1476
1477     default:
1478         break;
1479     }  /* end of switch */
1480
1481 }  /* end of suboption */
1482
1483 static void
1484 doclientstat(void)
1485 {
1486         clientstat(TELOPT_LINEMODE, WILL, 0);
1487 }
1488
1489 #define ADD(c)   *ncp++ = c
1490 #define ADD_DATA(c) { *ncp++ = c; if (c == SE || c == IAC) *ncp++ = c; }
1491 void
1492 send_status(void)
1493 {
1494         unsigned char statusbuf[256];
1495         unsigned char *ncp;
1496         unsigned char i;
1497
1498         ncp = statusbuf;
1499
1500         netflush();     /* get rid of anything waiting to go out */
1501
1502         ADD(IAC);
1503         ADD(SB);
1504         ADD(TELOPT_STATUS);
1505         ADD(TELQUAL_IS);
1506
1507         /*
1508          * We check the want_state rather than the current state,
1509          * because if we received a DO/WILL for an option that we
1510          * don't support, and the other side didn't send a DONT/WONT
1511          * in response to our WONT/DONT, then the "state" will be
1512          * WILL/DO, and the "want_state" will be WONT/DONT.  We
1513          * need to go by the latter.
1514          */
1515         for (i = 0; i < (unsigned char)NTELOPTS; i++) {
1516                 if (my_want_state_is_will(i)) {
1517                         ADD(WILL);
1518                         ADD_DATA(i);
1519                         if (i == IAC)
1520                                 ADD(IAC);
1521                 }
1522                 if (his_want_state_is_will(i)) {
1523                         ADD(DO);
1524                         ADD_DATA(i);
1525                         if (i == IAC)
1526                                 ADD(IAC);
1527                 }
1528         }
1529
1530         if (his_want_state_is_will(TELOPT_LFLOW)) {
1531                 ADD(SB);
1532                 ADD(TELOPT_LFLOW);
1533                 if (flowmode) {
1534                         ADD(LFLOW_ON);
1535                 } else {
1536                         ADD(LFLOW_OFF);
1537                 }
1538                 ADD(SE);
1539
1540                 if (restartany >= 0) {
1541                         ADD(SB);
1542                         ADD(TELOPT_LFLOW);
1543                         if (restartany) {
1544                                 ADD(LFLOW_RESTART_ANY);
1545                         } else {
1546                                 ADD(LFLOW_RESTART_XON);
1547                         }
1548                         ADD(SE);
1549                 }
1550         }
1551
1552 #ifdef  LINEMODE
1553         if (his_want_state_is_will(TELOPT_LINEMODE)) {
1554                 unsigned char *cp, *cpe;
1555                 int len;
1556
1557                 ADD(SB);
1558                 ADD(TELOPT_LINEMODE);
1559                 ADD(LM_MODE);
1560                 ADD_DATA(editmode);
1561                 ADD(SE);
1562
1563                 ADD(SB);
1564                 ADD(TELOPT_LINEMODE);
1565                 ADD(LM_SLC);
1566                 start_slc(0);
1567                 send_slc();
1568                 len = end_slc(&cp);
1569                 for (cpe = cp + len; cp < cpe; cp++)
1570                         ADD_DATA(*cp);
1571                 ADD(SE);
1572         }
1573 #endif  /* LINEMODE */
1574
1575         ADD(IAC);
1576         ADD(SE);
1577
1578         output_datalen(statusbuf, ncp - statusbuf);
1579         netflush();     /* Send it on its way */
1580
1581         DIAG(TD_OPTIONS,
1582                 {printsub('>', statusbuf, ncp - statusbuf); netflush();});
1583 }
1584
1585 /*
1586  * This function appends data to nfrontp and advances nfrontp.
1587  * Returns the number of characters written altogether (the
1588  * buffer may have been flushed in the process).
1589  */
1590
1591 int
1592 output_data(const char *format, ...)
1593 {
1594         va_list args;
1595         int len;
1596         char *buf;
1597
1598         va_start(args, format);
1599         if ((len = vasprintf(&buf, format, args)) == -1) {
1600                 va_end(args);
1601                 return -1;
1602         }
1603         output_datalen(buf, len);
1604         va_end(args);
1605         free(buf);
1606         return (len);
1607 }
1608
1609 void
1610 output_datalen(const char *buf, int len)
1611 {
1612         int remaining, copied;
1613
1614         remaining = BUFSIZ - (nfrontp - netobuf);
1615         while (len > 0) {
1616                 /* Free up enough space if the room is too low*/
1617                 if ((len > BUFSIZ ? BUFSIZ : len) > remaining) {
1618                         netflush();
1619                         remaining = BUFSIZ - (nfrontp - netobuf);
1620                 }
1621
1622                 /* Copy out as much as will fit */
1623                 copied = remaining > len ? len : remaining;
1624                 memmove(nfrontp, buf, copied);
1625                 nfrontp += copied;
1626                 len -= copied;
1627                 remaining -= copied;
1628                 buf += copied;
1629         }
1630         return;
1631 }