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. 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 #if 0
  35 #ifndef lint
  36 static const char sccsid[] = "@(#)state.c       8.5 (Berkeley) 5/30/95";
  37 #endif
  38 #endif
  39 #include <sys/cdefs.h>
  40 __FBSDID("$FreeBSD$");
  41
  42 #include <stdarg.h>
  43 #include "telnetd.h"
  44 #ifdef  AUTHENTICATION
  45 #include <libtelnet/auth.h>
  46 #endif
  47 #ifdef  ENCRYPTION
  48 #include <libtelnet/encrypt.h>
  49 #endif
  50
  51 unsigned char   doopt[] = { IAC, DO, '%', 'c', 0 };
  52 unsigned char   dont[] = { IAC, DONT, '%', 'c', 0 };
  53 unsigned char   will[] = { IAC, WILL, '%', 'c', 0 };
  54 unsigned char   wont[] = { IAC, WONT, '%', 'c', 0 };
  55 int     not42 = 1;
  56
  57 /*
  58  * Buffer for sub-options, and macros
  59  * for suboptions buffer manipulations
  60  */
  61 unsigned char subbuffer[512], *subpointer= subbuffer, *subend= subbuffer;
  62
  63 #define SB_CLEAR()      subpointer = subbuffer
  64 #define SB_TERM()       { subend = subpointer; SB_CLEAR(); }
  65 #define SB_ACCUM(c)     if (subpointer < (subbuffer+sizeof subbuffer)) { \
  66                                 *subpointer++ = (c); \
  67                         }
  68 #define SB_GET()        ((*subpointer++)&0xff)
  69 #define SB_EOF()        (subpointer >= subend)
  70 #define SB_LEN()        (subend - subpointer)
  71
  72 #ifdef  ENV_HACK
  73 unsigned char *subsave;
  74 #define SB_SAVE()       subsave = subpointer;
  75 #define SB_RESTORE()    subpointer = subsave;
  76 #endif
  77
  78
  79 /*
  80  * State for recv fsm
  81  */
  82 #define TS_DATA         0       /* base state */
  83 #define TS_IAC          1       /* look for double IAC's */
  84 #define TS_CR           2       /* CR-LF ->'s CR */
  85 #define TS_SB           3       /* throw away begin's... */
  86 #define TS_SE           4       /* ...end's (suboption negotiation) */
  87 #define TS_WILL         5       /* will option negotiation */
  88 #define TS_WONT         6       /* wont " */
  89 #define TS_DO           7       /* do " */
  90 #define TS_DONT         8       /* dont " */
  91
  92 static void doclientstat(void);
  93
  94 void
  95 telrcv(void)
  96 {
  97         int c;
  98         static int state = TS_DATA;
  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                         /* FALLTHROUGH */
 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                                 output_data("%c%c", IAC, DM);
 209                                 neturg = nfrontp-1; /* off by one XXX */
 210                                 DIAG(TD_OPTIONS,
 211                                         printoption("td: send IAC", DM));
 212                                 break;
 213                             }
 214
 215                         /*
 216                          * Erase Character and
 217                          * Erase Line
 218                          */
 219                         case EC:
 220                         case EL:
 221                             {
 222                                 cc_t ch;
 223
 224                                 DIAG(TD_OPTIONS,
 225                                         printoption("td: recv IAC", c));
 226                                 ptyflush();     /* half-hearted */
 227                                 init_termbuf();
 228                                 if (c == EC)
 229                                         ch = *slctab[SLC_EC].sptr;
 230                                 else
 231                                         ch = *slctab[SLC_EL].sptr;
 232                                 if (ch != (cc_t)(_POSIX_VDISABLE))
 233                                         *pfrontp++ = (unsigned char)ch;
 234                                 break;
 235                             }
 236
 237                         /*
 238                          * Check for urgent data...
 239                          */
 240                         case DM:
 241                                 DIAG(TD_OPTIONS,
 242                                         printoption("td: recv IAC", c));
 243                                 SYNCHing = stilloob(net);
 244                                 settimer(gotDM);
 245                                 break;
 246
 247
 248                         /*
 249                          * Begin option subnegotiation...
 250                          */
 251                         case SB:
 252                                 state = TS_SB;
 253                                 SB_CLEAR();
 254                                 continue;
 255
 256                         case WILL:
 257                                 state = TS_WILL;
 258                                 continue;
 259
 260                         case WONT:
 261                                 state = TS_WONT;
 262                                 continue;
 263
 264                         case DO:
 265                                 state = TS_DO;
 266                                 continue;
 267
 268                         case DONT:
 269                                 state = TS_DONT;
 270                                 continue;
 271                         case EOR:
 272                                 if (his_state_is_will(TELOPT_EOR))
 273                                         doeof();
 274                                 break;
 275
 276                         /*
 277                          * Handle RFC 10xx Telnet linemode option additions
 278                          * to command stream (EOF, SUSP, ABORT).
 279                          */
 280                         case xEOF:
 281                                 doeof();
 282                                 break;
 283
 284                         case SUSP:
 285                                 sendsusp();
 286                                 break;
 287
 288                         case ABORT:
 289                                 sendbrk();
 290                                 break;
 291
 292                         case IAC:
 293                                 *pfrontp++ = c;
 294                                 break;
 295                         }
 296                         state = TS_DATA;
 297                         break;
 298
 299                 case TS_SB:
 300                         if (c == IAC) {
 301                                 state = TS_SE;
 302                         } else {
 303                                 SB_ACCUM(c);
 304                         }
 305                         break;
 306
 307                 case TS_SE:
 308                         if (c != SE) {
 309                                 if (c != IAC) {
 310                                         /*
 311                                          * bad form of suboption negotiation.
 312                                          * handle it in such a way as to avoid
 313                                          * damage to local state.  Parse
 314                                          * suboption buffer found so far,
 315                                          * then treat remaining stream as
 316                                          * another command sequence.
 317                                          */
 318
 319                                         /* for DIAGNOSTICS */
 320                                         SB_ACCUM(IAC);
 321                                         SB_ACCUM(c);
 322                                         subpointer -= 2;
 323
 324                                         SB_TERM();
 325                                         suboption();
 326                                         state = TS_IAC;
 327                                         goto gotiac;
 328                                 }
 329                                 SB_ACCUM(c);
 330                                 state = TS_SB;
 331                         } else {
 332                                 /* for DIAGNOSTICS */
 333                                 SB_ACCUM(IAC);
 334                                 SB_ACCUM(SE);
 335                                 subpointer -= 2;
 336
 337                                 SB_TERM();
 338                                 suboption();    /* handle sub-option */
 339                                 state = TS_DATA;
 340                         }
 341                         break;
 342
 343                 case TS_WILL:
 344                         willoption(c);
 345                         state = TS_DATA;
 346                         continue;
 347
 348                 case TS_WONT:
 349                         wontoption(c);
 350                         state = TS_DATA;
 351                         continue;
 352
 353                 case TS_DO:
 354                         dooption(c);
 355                         state = TS_DATA;
 356                         continue;
 357
 358                 case TS_DONT:
 359                         dontoption(c);
 360                         state = TS_DATA;
 361                         continue;
 362
 363                 default:
 364                         syslog(LOG_ERR, "panic state=%d", state);
 365                         printf("telnetd: panic state=%d\n", state);
 366                         exit(1);
 367                 }
 368         }
 369 }  /* end of telrcv */
 370
 371 /*
 372  * The will/wont/do/dont state machines are based on Dave Borman's
 373  * Telnet option processing state machine.
 374  *
 375  * These correspond to the following states:
 376  *      my_state = the last negotiated state
 377  *      want_state = what I want the state to go to
 378  *      want_resp = how many requests I have sent
 379  * All state defaults are negative, and resp defaults to 0.
 380  *
 381  * When initiating a request to change state to new_state:
 382  *
 383  * if ((want_resp == 0 && new_state == my_state) || want_state == new_state) {
 384  *      do nothing;
 385  * } else {
 386  *      want_state = new_state;
 387  *      send new_state;
 388  *      want_resp++;
 389  * }
 390  *
 391  * When receiving new_state:
 392  *
 393  * if (want_resp) {
 394  *      want_resp--;
 395  *      if (want_resp && (new_state == my_state))
 396  *              want_resp--;
 397  * }
 398  * if ((want_resp == 0) && (new_state != want_state)) {
 399  *      if (ok_to_switch_to new_state)
 400  *              want_state = new_state;
 401  *      else
 402  *              want_resp++;
 403  *      send want_state;
 404  * }
 405  * my_state = new_state;
 406  *
 407  * Note that new_state is implied in these functions by the function itself.
 408  * will and do imply positive new_state, wont and dont imply negative.
 409  *
 410  * Finally, there is one catch.  If we send a negative response to a
 411  * positive request, my_state will be the positive while want_state will
 412  * remain negative.  my_state will revert to negative when the negative
 413  * acknowlegment arrives from the peer.  Thus, my_state generally tells
 414  * us not only the last negotiated state, but also tells us what the peer
 415  * wants to be doing as well.  It is important to understand this difference
 416  * as we may wish to be processing data streams based on our desired state
 417  * (want_state) or based on what the peer thinks the state is (my_state).
 418  *
 419  * This all works fine because if the peer sends a positive request, the data
 420  * that we receive prior to negative acknowlegment will probably be affected
 421  * by the positive state, and we can process it as such (if we can; if we
 422  * can't then it really doesn't matter).  If it is that important, then the
 423  * peer probably should be buffering until this option state negotiation
 424  * is complete.
 425  *
 426  */
 427 void
 428 send_do(int option, int init)
 429 {
 430         if (init) {
 431                 if ((do_dont_resp[option] == 0 && his_state_is_will(option)) ||
 432                     his_want_state_is_will(option))
 433                         return;
 434                 /*
 435                  * Special case for TELOPT_TM:  We send a DO, but pretend
 436                  * that we sent a DONT, so that we can send more DOs if
 437                  * we want to.
 438                  */
 439                 if (option == TELOPT_TM)
 440                         set_his_want_state_wont(option);
 441                 else
 442                         set_his_want_state_will(option);
 443                 do_dont_resp[option]++;
 444         }
 445         output_data((const char *)doopt, option);
 446
 447         DIAG(TD_OPTIONS, printoption("td: send do", option));
 448 }
 449
 450 void
 451 willoption(int option)
 452 {
 453         int changeok = 0;
 454         void (*func)(void) = 0;
 455
 456         /*
 457          * process input from peer.
 458          */
 459
 460         DIAG(TD_OPTIONS, printoption("td: recv will", option));
 461
 462         if (do_dont_resp[option]) {
 463                 do_dont_resp[option]--;
 464                 if (do_dont_resp[option] && his_state_is_will(option))
 465                         do_dont_resp[option]--;
 466         }
 467         if (do_dont_resp[option] == 0) {
 468             if (his_want_state_is_wont(option)) {
 469                 switch (option) {
 470
 471                 case TELOPT_BINARY:
 472                         init_termbuf();
 473                         tty_binaryin(1);
 474                         set_termbuf();
 475                         changeok++;
 476                         break;
 477
 478                 case TELOPT_ECHO:
 479                         /*
 480                          * See comments below for more info.
 481                          */
 482                         not42 = 0;      /* looks like a 4.2 system */
 483                         break;
 484
 485                 case TELOPT_TM:
 486 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
 487                         /*
 488                          * This telnetd implementation does not really
 489                          * support timing marks, it just uses them to
 490                          * support the kludge linemode stuff.  If we
 491                          * receive a will or wont TM in response to our
 492                          * do TM request that may have been sent to
 493                          * determine kludge linemode support, process
 494                          * it, otherwise TM should get a negative
 495                          * response back.
 496                          */
 497                         /*
 498                          * Handle the linemode kludge stuff.
 499                          * If we are not currently supporting any
 500                          * linemode at all, then we assume that this
 501                          * is the client telling us to use kludge
 502                          * linemode in response to our query.  Set the
 503                          * linemode type that is to be supported, note
 504                          * that the client wishes to use linemode, and
 505                          * eat the will TM as though it never arrived.
 506                          */
 507                         if (lmodetype < KLUDGE_LINEMODE) {
 508                                 lmodetype = KLUDGE_LINEMODE;
 509                                 clientstat(TELOPT_LINEMODE, WILL, 0);
 510                                 send_wont(TELOPT_SGA, 1);
 511                         } else if (lmodetype == NO_AUTOKLUDGE) {
 512                                 lmodetype = KLUDGE_OK;
 513                         }
 514 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
 515                         /*
 516                          * We never respond to a WILL TM, and
 517                          * we leave the state WONT.
 518                          */
 519                         return;
 520
 521                 case TELOPT_LFLOW:
 522                         /*
 523                          * If we are going to support flow control
 524                          * option, then don't worry peer that we can't
 525                          * change the flow control characters.
 526                          */
 527                         slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
 528                         slctab[SLC_XON].defset.flag |= SLC_DEFAULT;
 529                         slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
 530                         slctab[SLC_XOFF].defset.flag |= SLC_DEFAULT;
 531                 case TELOPT_TTYPE:
 532                 case TELOPT_SGA:
 533                 case TELOPT_NAWS:
 534                 case TELOPT_TSPEED:
 535                 case TELOPT_XDISPLOC:
 536                 case TELOPT_NEW_ENVIRON:
 537                 case TELOPT_OLD_ENVIRON:
 538                         changeok++;
 539                         break;
 540
 541 #ifdef  LINEMODE
 542                 case TELOPT_LINEMODE:
 543 # ifdef KLUDGELINEMODE
 544                         /*
 545                          * Note client's desire to use linemode.
 546                          */
 547                         lmodetype = REAL_LINEMODE;
 548 # endif /* KLUDGELINEMODE */
 549                         func = doclientstat;
 550                         changeok++;
 551                         break;
 552 #endif  /* LINEMODE */
 553
 554 #ifdef  AUTHENTICATION
 555                 case TELOPT_AUTHENTICATION:
 556                         if (auth_level >= 0) {
 557                                 func = auth_request;
 558                                 changeok++;
 559                         }
 560                         break;
 561 #endif
 562
 563 #ifdef  ENCRYPTION
 564                 case TELOPT_ENCRYPT:
 565                         func = encrypt_send_support;
 566                         changeok++;
 567                         break;
 568 #endif  /* ENCRYPTION */
 569
 570                 default:
 571                         break;
 572                 }
 573                 if (changeok) {
 574                         set_his_want_state_will(option);
 575                         send_do(option, 0);
 576                 } else {
 577                         do_dont_resp[option]++;
 578                         send_dont(option, 0);
 579                 }
 580             } else {
 581                 /*
 582                  * Option processing that should happen when
 583                  * we receive conformation of a change in
 584                  * state that we had requested.
 585                  */
 586                 switch (option) {
 587                 case TELOPT_ECHO:
 588                         not42 = 0;      /* looks like a 4.2 system */
 589                         /*
 590                          * Egads, he responded "WILL ECHO".  Turn
 591                          * it off right now!
 592                          */
 593                         send_dont(option, 1);
 594                         /*
 595                          * "WILL ECHO".  Kludge upon kludge!
 596                          * A 4.2 client is now echoing user input at
 597                          * the tty.  This is probably undesireable and
 598                          * it should be stopped.  The client will
 599                          * respond WONT TM to the DO TM that we send to
 600                          * check for kludge linemode.  When the WONT TM
 601                          * arrives, linemode will be turned off and a
 602                          * change propogated to the pty.  This change
 603                          * will cause us to process the new pty state
 604                          * in localstat(), which will notice that
 605                          * linemode is off and send a WILL ECHO
 606                          * so that we are properly in character mode and
 607                          * all is well.
 608                          */
 609                         break;
 610 #ifdef  LINEMODE
 611                 case TELOPT_LINEMODE:
 612 # ifdef KLUDGELINEMODE
 613                         /*
 614                          * Note client's desire to use linemode.
 615                          */
 616                         lmodetype = REAL_LINEMODE;
 617 # endif /* KLUDGELINEMODE */
 618                         func = doclientstat;
 619                         break;
 620 #endif  /* LINEMODE */
 621
 622 #ifdef  AUTHENTICATION
 623                 case TELOPT_AUTHENTICATION:
 624                         func = auth_request;
 625                         break;
 626 #endif
 627
 628 #ifdef  ENCRYPTION
 629                 case TELOPT_ENCRYPT:
 630                         func = encrypt_send_support;
 631                         break;
 632 #endif  /* ENCRYPTION */
 633                 case TELOPT_LFLOW:
 634                         func = flowstat;
 635                         break;
 636                 }
 637             }
 638         }
 639         set_his_state_will(option);
 640         if (func)
 641                 (*func)();
 642 }  /* end of willoption */
 643
 644 void
 645 send_dont(int option, int init)
 646 {
 647         if (init) {
 648                 if ((do_dont_resp[option] == 0 && his_state_is_wont(option)) ||
 649                     his_want_state_is_wont(option))
 650                         return;
 651                 set_his_want_state_wont(option);
 652                 do_dont_resp[option]++;
 653         }
 654         output_data((const char *)dont, option);
 655
 656         DIAG(TD_OPTIONS, printoption("td: send dont", option));
 657 }
 658
 659 void
 660 wontoption(int option)
 661 {
 662         /*
 663          * Process client input.
 664          */
 665
 666         DIAG(TD_OPTIONS, printoption("td: recv wont", option));
 667
 668         if (do_dont_resp[option]) {
 669                 do_dont_resp[option]--;
 670                 if (do_dont_resp[option] && his_state_is_wont(option))
 671                         do_dont_resp[option]--;
 672         }
 673         if (do_dont_resp[option] == 0) {
 674             if (his_want_state_is_will(option)) {
 675                 /* it is always ok to change to negative state */
 676                 switch (option) {
 677                 case TELOPT_ECHO:
 678                         not42 = 1; /* doesn't seem to be a 4.2 system */
 679                         break;
 680
 681                 case TELOPT_BINARY:
 682                         init_termbuf();
 683                         tty_binaryin(0);
 684                         set_termbuf();
 685                         break;
 686
 687 #ifdef  LINEMODE
 688                 case TELOPT_LINEMODE:
 689 # ifdef KLUDGELINEMODE
 690                         /*
 691                          * If real linemode is supported, then client is
 692                          * asking to turn linemode off.
 693                          */
 694                         if (lmodetype != REAL_LINEMODE)
 695                                 break;
 696                         lmodetype = KLUDGE_LINEMODE;
 697 # endif /* KLUDGELINEMODE */
 698                         clientstat(TELOPT_LINEMODE, WONT, 0);
 699                         break;
 700 #endif  /* LINEMODE */
 701
 702                 case TELOPT_TM:
 703                         /*
 704                          * If we get a WONT TM, and had sent a DO TM,
 705                          * don't respond with a DONT TM, just leave it
 706                          * as is.  Short circut the state machine to
 707                          * achive this.
 708                          */
 709                         set_his_want_state_wont(TELOPT_TM);
 710                         return;
 711
 712                 case TELOPT_LFLOW:
 713                         /*
 714                          * If we are not going to support flow control
 715                          * option, then let peer know that we can't
 716                          * change the flow control characters.
 717                          */
 718                         slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
 719                         slctab[SLC_XON].defset.flag |= SLC_CANTCHANGE;
 720                         slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
 721                         slctab[SLC_XOFF].defset.flag |= SLC_CANTCHANGE;
 722                         break;
 723
 724 #ifdef  AUTHENTICATION
 725                 case TELOPT_AUTHENTICATION:
 726                         auth_finished(0, AUTH_REJECT);
 727                         break;
 728 #endif
 729
 730                 /*
 731                  * For options that we might spin waiting for
 732                  * sub-negotiation, if the client turns off the
 733                  * option rather than responding to the request,
 734                  * we have to treat it here as if we got a response
 735                  * to the sub-negotiation, (by updating the timers)
 736                  * so that we'll break out of the loop.
 737                  */
 738                 case TELOPT_TTYPE:
 739                         settimer(ttypesubopt);
 740                         break;
 741
 742                 case TELOPT_TSPEED:
 743                         settimer(tspeedsubopt);
 744                         break;
 745
 746                 case TELOPT_XDISPLOC:
 747                         settimer(xdisplocsubopt);
 748                         break;
 749
 750                 case TELOPT_OLD_ENVIRON:
 751                         settimer(oenvironsubopt);
 752                         break;
 753
 754                 case TELOPT_NEW_ENVIRON:
 755                         settimer(environsubopt);
 756                         break;
 757
 758                 default:
 759                         break;
 760                 }
 761                 set_his_want_state_wont(option);
 762                 if (his_state_is_will(option))
 763                         send_dont(option, 0);
 764             } else {
 765                 switch (option) {
 766                 case TELOPT_TM:
 767 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
 768                         if (lmodetype < NO_AUTOKLUDGE) {
 769                                 lmodetype = NO_LINEMODE;
 770                                 clientstat(TELOPT_LINEMODE, WONT, 0);
 771                                 send_will(TELOPT_SGA, 1);
 772                                 send_will(TELOPT_ECHO, 1);
 773                         }
 774 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
 775                         break;
 776
 777 #ifdef AUTHENTICATION
 778                 case TELOPT_AUTHENTICATION:
 779                         auth_finished(0, AUTH_REJECT);
 780                         break;
 781 #endif
 782                 default:
 783                         break;
 784                 }
 785             }
 786         }
 787         set_his_state_wont(option);
 788
 789 }  /* end of wontoption */
 790
 791 void
 792 send_will(int option, int init)
 793 {
 794         if (init) {
 795                 if ((will_wont_resp[option] == 0 && my_state_is_will(option))||
 796                     my_want_state_is_will(option))
 797                         return;
 798                 set_my_want_state_will(option);
 799                 will_wont_resp[option]++;
 800         }
 801         output_data((const char *)will, option);
 802
 803         DIAG(TD_OPTIONS, printoption("td: send will", option));
 804 }
 805
 806 #if     !defined(LINEMODE) || !defined(KLUDGELINEMODE)
 807 /*
 808  * When we get a DONT SGA, we will try once to turn it
 809  * back on.  If the other side responds DONT SGA, we
 810  * leave it at that.  This is so that when we talk to
 811  * clients that understand KLUDGELINEMODE but not LINEMODE,
 812  * we'll keep them in char-at-a-time mode.
 813  */
 814 int turn_on_sga = 0;
 815 #endif
 816
 817 void
 818 dooption(int option)
 819 {
 820         int changeok = 0;
 821
 822         /*
 823          * Process client input.
 824          */
 825
 826         DIAG(TD_OPTIONS, printoption("td: recv do", option));
 827
 828         if (will_wont_resp[option]) {
 829                 will_wont_resp[option]--;
 830                 if (will_wont_resp[option] && my_state_is_will(option))
 831                         will_wont_resp[option]--;
 832         }
 833         if ((will_wont_resp[option] == 0) && (my_want_state_is_wont(option))) {
 834                 switch (option) {
 835                 case TELOPT_ECHO:
 836 #ifdef  LINEMODE
 837 # ifdef KLUDGELINEMODE
 838                         if (lmodetype == NO_LINEMODE)
 839 # else
 840                         if (his_state_is_wont(TELOPT_LINEMODE))
 841 # endif
 842 #endif
 843                         {
 844                                 init_termbuf();
 845                                 tty_setecho(1);
 846                                 set_termbuf();
 847                         }
 848                         changeok++;
 849                         break;
 850
 851                 case TELOPT_BINARY:
 852                         init_termbuf();
 853                         tty_binaryout(1);
 854                         set_termbuf();
 855                         changeok++;
 856                         break;
 857
 858                 case TELOPT_SGA:
 859 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
 860                         /*
 861                          * If kludge linemode is in use, then we must
 862                          * process an incoming do SGA for linemode
 863                          * purposes.
 864                          */
 865                         if (lmodetype == KLUDGE_LINEMODE) {
 866                                 /*
 867                                  * Receipt of "do SGA" in kludge
 868                                  * linemode is the peer asking us to
 869                                  * turn off linemode.  Make note of
 870                                  * the request.
 871                                  */
 872                                 clientstat(TELOPT_LINEMODE, WONT, 0);
 873                                 /*
 874                                  * If linemode did not get turned off
 875                                  * then don't tell peer that we did.
 876                                  * Breaking here forces a wont SGA to
 877                                  * be returned.
 878                                  */
 879                                 if (linemode)
 880                                         break;
 881                         }
 882 #else
 883                         turn_on_sga = 0;
 884 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
 885                         changeok++;
 886                         break;
 887
 888                 case TELOPT_STATUS:
 889                         changeok++;
 890                         break;
 891
 892                 case TELOPT_TM:
 893                         /*
 894                          * Special case for TM.  We send a WILL, but
 895                          * pretend we sent a WONT.
 896                          */
 897                         send_will(option, 0);
 898                         set_my_want_state_wont(option);
 899                         set_my_state_wont(option);
 900                         return;
 901
 902                 case TELOPT_LOGOUT:
 903                         /*
 904                          * When we get a LOGOUT option, respond
 905                          * with a WILL LOGOUT, make sure that
 906                          * it gets written out to the network,
 907                          * and then just go away...
 908                          */
 909                         set_my_want_state_will(TELOPT_LOGOUT);
 910                         send_will(TELOPT_LOGOUT, 0);
 911                         set_my_state_will(TELOPT_LOGOUT);
 912                         (void)netflush();
 913                         cleanup(0);
 914                         /* NOT REACHED */
 915                         break;
 916
 917 #ifdef  ENCRYPTION
 918                 case TELOPT_ENCRYPT:
 919                         changeok++;
 920                         break;
 921 #endif  /* ENCRYPTION */
 922                 case TELOPT_LINEMODE:
 923                 case TELOPT_TTYPE:
 924                 case TELOPT_NAWS:
 925                 case TELOPT_TSPEED:
 926                 case TELOPT_LFLOW:
 927                 case TELOPT_XDISPLOC:
 928 #ifdef  TELOPT_ENVIRON
 929                 case TELOPT_NEW_ENVIRON:
 930 #endif
 931                 case TELOPT_OLD_ENVIRON:
 932                 default:
 933                         break;
 934                 }
 935                 if (changeok) {
 936                         set_my_want_state_will(option);
 937                         send_will(option, 0);
 938                 } else {
 939                         will_wont_resp[option]++;
 940                         send_wont(option, 0);
 941                 }
 942         }
 943         set_my_state_will(option);
 944
 945 }  /* end of dooption */
 946
 947 void
 948 send_wont(int option, int init)
 949 {
 950         if (init) {
 951                 if ((will_wont_resp[option] == 0 && my_state_is_wont(option)) ||
 952                     my_want_state_is_wont(option))
 953                         return;
 954                 set_my_want_state_wont(option);
 955                 will_wont_resp[option]++;
 956         }
 957         output_data((const char *)wont, option);
 958
 959         DIAG(TD_OPTIONS, printoption("td: send wont", option));
 960 }
 961
 962 void
 963 dontoption(int option)
 964 {
 965         /*
 966          * Process client input.
 967          */
 968
 969
 970         DIAG(TD_OPTIONS, printoption("td: recv dont", option));
 971
 972         if (will_wont_resp[option]) {
 973                 will_wont_resp[option]--;
 974                 if (will_wont_resp[option] && my_state_is_wont(option))
 975                         will_wont_resp[option]--;
 976         }
 977         if ((will_wont_resp[option] == 0) && (my_want_state_is_will(option))) {
 978                 switch (option) {
 979                 case TELOPT_BINARY:
 980                         init_termbuf();
 981                         tty_binaryout(0);
 982                         set_termbuf();
 983                         break;
 984
 985                 case TELOPT_ECHO:       /* we should stop echoing */
 986 #ifdef  LINEMODE
 987 # ifdef KLUDGELINEMODE
 988                         if ((lmodetype != REAL_LINEMODE) &&
 989                             (lmodetype != KLUDGE_LINEMODE))
 990 # else
 991                         if (his_state_is_wont(TELOPT_LINEMODE))
 992 # endif
 993 #endif
 994                         {
 995                                 init_termbuf();
 996                                 tty_setecho(0);
 997                                 set_termbuf();
 998                         }
 999                         break;
1000
1001                 case TELOPT_SGA:
1002 #if     defined(LINEMODE) && defined(KLUDGELINEMODE)
1003                         /*
1004                          * If kludge linemode is in use, then we
1005                          * must process an incoming do SGA for
1006                          * linemode purposes.
1007                          */
1008                         if ((lmodetype == KLUDGE_LINEMODE) ||
1009                             (lmodetype == KLUDGE_OK)) {
1010                                 /*
1011                                  * The client is asking us to turn
1012                                  * linemode on.
1013                                  */
1014                                 lmodetype = KLUDGE_LINEMODE;
1015                                 clientstat(TELOPT_LINEMODE, WILL, 0);
1016                                 /*
1017                                  * If we did not turn line mode on,
1018                                  * then what do we say?  Will SGA?
1019                                  * This violates design of telnet.
1020                                  * Gross.  Very Gross.
1021                                  */
1022                         }
1023                         break;
1024 #else
1025                         set_my_want_state_wont(option);
1026                         if (my_state_is_will(option))
1027                                 send_wont(option, 0);
1028                         set_my_state_wont(option);
1029                         if (turn_on_sga ^= 1)
1030                                 send_will(option, 1);
1031                         return;
1032 #endif  /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
1033
1034                 default:
1035                         break;
1036                 }
1037
1038                 set_my_want_state_wont(option);
1039                 if (my_state_is_will(option))
1040                         send_wont(option, 0);
1041         }
1042         set_my_state_wont(option);
1043
1044 }  /* end of dontoption */
1045
1046 #ifdef  ENV_HACK
1047 int env_ovar = -1;
1048 int env_ovalue = -1;
1049 #else   /* ENV_HACK */
1050 # define env_ovar OLD_ENV_VAR
1051 # define env_ovalue OLD_ENV_VALUE
1052 #endif  /* ENV_HACK */
1053
1054 /*
1055  * suboption()
1056  *
1057  *      Look at the sub-option buffer, and try to be helpful to the other
1058  * side.
1059  *
1060  *      Currently we recognize:
1061  *
1062  *      Terminal type is
1063  *      Linemode
1064  *      Window size
1065  *      Terminal speed
1066  */
1067 void
1068 suboption(void)
1069 {
1070     int subchar;
1071
1072     DIAG(TD_OPTIONS, {netflush(); printsub('<', subpointer, SB_LEN()+2);});
1073
1074     subchar = SB_GET();
1075     switch (subchar) {
1076     case TELOPT_TSPEED: {
1077         int xspeed, rspeed;
1078
1079         if (his_state_is_wont(TELOPT_TSPEED))   /* Ignore if option disabled */
1080                 break;
1081
1082         settimer(tspeedsubopt);
1083
1084         if (SB_EOF() || SB_GET() != TELQUAL_IS)
1085                 return;
1086
1087         xspeed = atoi((char *)subpointer);
1088
1089         while (SB_GET() != ',' && !SB_EOF());
1090         if (SB_EOF())
1091                 return;
1092
1093         rspeed = atoi((char *)subpointer);
1094         clientstat(TELOPT_TSPEED, xspeed, rspeed);
1095
1096         break;
1097
1098     }  /* end of case TELOPT_TSPEED */
1099
1100     case TELOPT_TTYPE: {                /* Yaaaay! */
1101         static char terminalname[41];
1102
1103         if (his_state_is_wont(TELOPT_TTYPE))    /* Ignore if option disabled */
1104                 break;
1105         settimer(ttypesubopt);
1106
1107         if (SB_EOF() || SB_GET() != TELQUAL_IS) {
1108             return;             /* ??? XXX but, this is the most robust */
1109         }
1110
1111         terminaltype = terminalname;
1112
1113         while ((terminaltype < (terminalname + sizeof terminalname-1)) &&
1114                                                                     !SB_EOF()) {
1115             int c;
1116
1117             c = SB_GET();
1118             if (isupper(c)) {
1119                 c = tolower(c);
1120             }
1121             *terminaltype++ = c;    /* accumulate name */
1122         }
1123         *terminaltype = 0;
1124         terminaltype = terminalname;
1125         break;
1126     }  /* end of case TELOPT_TTYPE */
1127
1128     case TELOPT_NAWS: {
1129         int xwinsize, ywinsize;
1130
1131         if (his_state_is_wont(TELOPT_NAWS))     /* Ignore if option disabled */
1132                 break;
1133
1134         if (SB_EOF())
1135                 return;
1136         xwinsize = SB_GET() << 8;
1137         if (SB_EOF())
1138                 return;
1139         xwinsize |= SB_GET();
1140         if (SB_EOF())
1141                 return;
1142         ywinsize = SB_GET() << 8;
1143         if (SB_EOF())
1144                 return;
1145         ywinsize |= SB_GET();
1146         clientstat(TELOPT_NAWS, xwinsize, ywinsize);
1147
1148         break;
1149
1150     }  /* end of case TELOPT_NAWS */
1151
1152 #ifdef  LINEMODE
1153     case TELOPT_LINEMODE: {
1154         int request;
1155
1156         if (his_state_is_wont(TELOPT_LINEMODE)) /* Ignore if option disabled */
1157                 break;
1158         /*
1159          * Process linemode suboptions.
1160          */
1161         if (SB_EOF())
1162             break;              /* garbage was sent */
1163         request = SB_GET();     /* get will/wont */
1164
1165         if (SB_EOF())
1166             break;              /* another garbage check */
1167
1168         if (request == LM_SLC) {  /* SLC is not preceeded by WILL or WONT */
1169                 /*
1170                  * Process suboption buffer of slc's
1171                  */
1172                 start_slc(1);
1173                 do_opt_slc(subpointer, subend - subpointer);
1174                 (void) end_slc(0);
1175                 break;
1176         } else if (request == LM_MODE) {
1177                 if (SB_EOF())
1178                     return;
1179                 useeditmode = SB_GET();  /* get mode flag */
1180                 clientstat(LM_MODE, 0, 0);
1181                 break;
1182         }
1183
1184         if (SB_EOF())
1185             break;
1186         switch (SB_GET()) {  /* what suboption? */
1187         case LM_FORWARDMASK:
1188                 /*
1189                  * According to spec, only server can send request for
1190                  * forwardmask, and client can only return a positive response.
1191                  * So don't worry about it.
1192                  */
1193
1194         default:
1195                 break;
1196         }
1197         break;
1198     }  /* end of case TELOPT_LINEMODE */
1199 #endif
1200     case TELOPT_STATUS: {
1201         int mode;
1202
1203         if (SB_EOF())
1204             break;
1205         mode = SB_GET();
1206         switch (mode) {
1207         case TELQUAL_SEND:
1208             if (my_state_is_will(TELOPT_STATUS))
1209                 send_status();
1210             break;
1211
1212         case TELQUAL_IS:
1213             break;
1214
1215         default:
1216             break;
1217         }
1218         break;
1219     }  /* end of case TELOPT_STATUS */
1220
1221     case TELOPT_XDISPLOC: {
1222         if (SB_EOF() || SB_GET() != TELQUAL_IS)
1223                 return;
1224         settimer(xdisplocsubopt);
1225         subpointer[SB_LEN()] = '\0';
1226         (void)setenv("DISPLAY", (char *)subpointer, 1);
1227         break;
1228     }  /* end of case TELOPT_XDISPLOC */
1229
1230 #ifdef  TELOPT_NEW_ENVIRON
1231     case TELOPT_NEW_ENVIRON:
1232 #endif
1233     case TELOPT_OLD_ENVIRON: {
1234         int c;
1235         char *cp, *varp, *valp;
1236
1237         if (SB_EOF())
1238                 return;
1239         c = SB_GET();
1240         if (c == TELQUAL_IS) {
1241                 if (subchar == TELOPT_OLD_ENVIRON)
1242                         settimer(oenvironsubopt);
1243                 else
1244                         settimer(environsubopt);
1245         } else if (c != TELQUAL_INFO) {
1246                 return;
1247         }
1248
1249 #ifdef  TELOPT_NEW_ENVIRON
1250         if (subchar == TELOPT_NEW_ENVIRON) {
1251             while (!SB_EOF()) {
1252                 c = SB_GET();
1253                 if ((c == NEW_ENV_VAR) || (c == ENV_USERVAR))
1254                         break;
1255             }
1256         } else
1257 #endif
1258         {
1259 #ifdef  ENV_HACK
1260             /*
1261              * We only want to do this if we haven't already decided
1262              * whether or not the other side has its VALUE and VAR
1263              * reversed.
1264              */
1265             if (env_ovar < 0) {
1266                 int last = -1;          /* invalid value */
1267                 int empty = 0;
1268                 int got_var = 0, got_value = 0, got_uservar = 0;
1269
1270                 /*
1271                  * The other side might have its VALUE and VAR values
1272                  * reversed.  To be interoperable, we need to determine
1273                  * which way it is.  If the first recognized character
1274                  * is a VAR or VALUE, then that will tell us what
1275                  * type of client it is.  If the fist recognized
1276                  * character is a USERVAR, then we continue scanning
1277                  * the suboption looking for two consecutive
1278                  * VAR or VALUE fields.  We should not get two
1279                  * consecutive VALUE fields, so finding two
1280                  * consecutive VALUE or VAR fields will tell us
1281                  * what the client is.
1282                  */
1283                 SB_SAVE();
1284                 while (!SB_EOF()) {
1285                         c = SB_GET();
1286                         switch(c) {
1287                         case OLD_ENV_VAR:
1288                                 if (last < 0 || last == OLD_ENV_VAR
1289                                     || (empty && (last == OLD_ENV_VALUE)))
1290                                         goto env_ovar_ok;
1291                                 got_var++;
1292                                 last = OLD_ENV_VAR;
1293                                 break;
1294                         case OLD_ENV_VALUE:
1295                                 if (last < 0 || last == OLD_ENV_VALUE
1296                                     || (empty && (last == OLD_ENV_VAR)))
1297                                         goto env_ovar_wrong;
1298                                 got_value++;
1299                                 last = OLD_ENV_VALUE;
1300                                 break;
1301                         case ENV_USERVAR:
1302                                 /* count strings of USERVAR as one */
1303                                 if (last != ENV_USERVAR)
1304                                         got_uservar++;
1305                                 if (empty) {
1306                                         if (last == OLD_ENV_VALUE)
1307                                                 goto env_ovar_ok;
1308                                         if (last == OLD_ENV_VAR)
1309                                                 goto env_ovar_wrong;
1310                                 }
1311                                 last = ENV_USERVAR;
1312                                 break;
1313                         case ENV_ESC:
1314                                 if (!SB_EOF())
1315                                         c = SB_GET();
1316                                 /* FALLTHROUGH */
1317                         default:
1318                                 empty = 0;
1319                                 continue;
1320                         }
1321                         empty = 1;
1322                 }
1323                 if (empty) {
1324                         if (last == OLD_ENV_VALUE)
1325                                 goto env_ovar_ok;
1326                         if (last == OLD_ENV_VAR)
1327                                 goto env_ovar_wrong;
1328                 }
1329                 /*
1330                  * Ok, the first thing was a USERVAR, and there
1331                  * are not two consecutive VAR or VALUE commands,
1332                  * and none of the VAR or VALUE commands are empty.
1333                  * If the client has sent us a well-formed option,
1334                  * then the number of VALUEs received should always
1335                  * be less than or equal to the number of VARs and
1336                  * USERVARs received.
1337                  *
1338                  * If we got exactly as many VALUEs as VARs and
1339                  * USERVARs, the client has the same definitions.
1340                  *
1341                  * If we got exactly as many VARs as VALUEs and
1342                  * USERVARS, the client has reversed definitions.
1343                  */
1344                 if (got_uservar + got_var == got_value) {
1345             env_ovar_ok:
1346                         env_ovar = OLD_ENV_VAR;
1347                         env_ovalue = OLD_ENV_VALUE;
1348                 } else if (got_uservar + got_value == got_var) {
1349             env_ovar_wrong:
1350                         env_ovar = OLD_ENV_VALUE;
1351                         env_ovalue = OLD_ENV_VAR;
1352                         DIAG(TD_OPTIONS,
1353                             output_data("ENVIRON VALUE and VAR are reversed!\r\n"));
1354
1355                 }
1356             }
1357             SB_RESTORE();
1358 #endif
1359
1360             while (!SB_EOF()) {
1361                 c = SB_GET();
1362                 if ((c == env_ovar) || (c == ENV_USERVAR))
1363                         break;
1364             }
1365         }
1366
1367         if (SB_EOF())
1368                 return;
1369
1370         cp = varp = (char *)subpointer;
1371         valp = 0;
1372
1373         while (!SB_EOF()) {
1374                 c = SB_GET();
1375                 if (subchar == TELOPT_OLD_ENVIRON) {
1376                         if (c == env_ovar)
1377                                 c = NEW_ENV_VAR;
1378                         else if (c == env_ovalue)
1379                                 c = NEW_ENV_VALUE;
1380                 }
1381                 switch (c) {
1382
1383                 case NEW_ENV_VALUE:
1384                         *cp = '\0';
1385                         cp = valp = (char *)subpointer;
1386                         break;
1387
1388                 case NEW_ENV_VAR:
1389                 case ENV_USERVAR:
1390                         *cp = '\0';
1391                         if (valp)
1392                                 (void)setenv(varp, valp, 1);
1393                         else
1394                                 unsetenv(varp);
1395                         cp = varp = (char *)subpointer;
1396                         valp = 0;
1397                         break;
1398
1399                 case ENV_ESC:
1400                         if (SB_EOF())
1401                                 break;
1402                         c = SB_GET();
1403                         /* FALLTHROUGH */
1404                 default:
1405                         *cp++ = c;
1406                         break;
1407                 }
1408         }
1409         *cp = '\0';
1410         if (valp)
1411                 (void)setenv(varp, valp, 1);
1412         else
1413                 unsetenv(varp);
1414         break;
1415     }  /* end of case TELOPT_NEW_ENVIRON */
1416 #ifdef  AUTHENTICATION
1417     case TELOPT_AUTHENTICATION:
1418         if (SB_EOF())
1419                 break;
1420         switch(SB_GET()) {
1421         case TELQUAL_SEND:
1422         case TELQUAL_REPLY:
1423                 /*
1424                  * These are sent by us and cannot be sent by
1425                  * the client.
1426                  */
1427                 break;
1428         case TELQUAL_IS:
1429                 auth_is(subpointer, SB_LEN());
1430                 break;
1431         case TELQUAL_NAME:
1432                 auth_name(subpointer, SB_LEN());
1433                 break;
1434         }
1435         break;
1436 #endif
1437 #ifdef  ENCRYPTION
1438     case TELOPT_ENCRYPT:
1439         if (SB_EOF())
1440                 break;
1441         switch(SB_GET()) {
1442         case ENCRYPT_SUPPORT:
1443                 encrypt_support(subpointer, SB_LEN());
1444                 break;
1445         case ENCRYPT_IS:
1446                 encrypt_is(subpointer, SB_LEN());
1447                 break;
1448         case ENCRYPT_REPLY:
1449                 encrypt_reply(subpointer, SB_LEN());
1450                 break;
1451         case ENCRYPT_START:
1452                 encrypt_start(subpointer, SB_LEN());
1453                 break;
1454         case ENCRYPT_END:
1455                 encrypt_end();
1456                 break;
1457         case ENCRYPT_REQSTART:
1458                 encrypt_request_start(subpointer, SB_LEN());
1459                 break;
1460         case ENCRYPT_REQEND:
1461                 /*
1462                  * We can always send an REQEND so that we cannot
1463                  * get stuck encrypting.  We should only get this
1464                  * if we have been able to get in the correct mode
1465                  * anyhow.
1466                  */
1467                 encrypt_request_end();
1468                 break;
1469         case ENCRYPT_ENC_KEYID:
1470                 encrypt_enc_keyid(subpointer, SB_LEN());
1471                 break;
1472         case ENCRYPT_DEC_KEYID:
1473                 encrypt_dec_keyid(subpointer, SB_LEN());
1474                 break;
1475         default:
1476                 break;
1477         }
1478         break;
1479 #endif  /* ENCRYPTION */
1480
1481     default:
1482         break;
1483     }  /* end of switch */
1484
1485 }  /* end of suboption */
1486
1487 static void
1488 doclientstat(void)
1489 {
1490         clientstat(TELOPT_LINEMODE, WILL, 0);
1491 }
1492
1493 #define ADD(c)   *ncp++ = c
1494 #define ADD_DATA(c) { *ncp++ = c; if (c == SE || c == IAC) *ncp++ = c; }
1495 void
1496 send_status(void)
1497 {
1498         unsigned char statusbuf[256];
1499         unsigned char *ncp;
1500         unsigned char i;
1501
1502         ncp = statusbuf;
1503
1504         netflush();     /* get rid of anything waiting to go out */
1505
1506         ADD(IAC);
1507         ADD(SB);
1508         ADD(TELOPT_STATUS);
1509         ADD(TELQUAL_IS);
1510
1511         /*
1512          * We check the want_state rather than the current state,
1513          * because if we received a DO/WILL for an option that we
1514          * don't support, and the other side didn't send a DONT/WONT
1515          * in response to our WONT/DONT, then the "state" will be
1516          * WILL/DO, and the "want_state" will be WONT/DONT.  We
1517          * need to go by the latter.
1518          */
1519         for (i = 0; i < (unsigned char)NTELOPTS; i++) {
1520                 if (my_want_state_is_will(i)) {
1521                         ADD(WILL);
1522                         ADD_DATA(i);
1523                         if (i == IAC)
1524                                 ADD(IAC);
1525                 }
1526                 if (his_want_state_is_will(i)) {
1527                         ADD(DO);
1528                         ADD_DATA(i);
1529                         if (i == IAC)
1530                                 ADD(IAC);
1531                 }
1532         }
1533
1534         if (his_want_state_is_will(TELOPT_LFLOW)) {
1535                 ADD(SB);
1536                 ADD(TELOPT_LFLOW);
1537                 if (flowmode) {
1538                         ADD(LFLOW_ON);
1539                 } else {
1540                         ADD(LFLOW_OFF);
1541                 }
1542                 ADD(SE);
1543
1544                 if (restartany >= 0) {
1545                         ADD(SB);
1546                         ADD(TELOPT_LFLOW);
1547                         if (restartany) {
1548                                 ADD(LFLOW_RESTART_ANY);
1549                         } else {
1550                                 ADD(LFLOW_RESTART_XON);
1551                         }
1552                         ADD(SE);
1553                 }
1554         }
1555
1556 #ifdef  LINEMODE
1557         if (his_want_state_is_will(TELOPT_LINEMODE)) {
1558                 unsigned char *cp, *cpe;
1559                 int len;
1560
1561                 ADD(SB);
1562                 ADD(TELOPT_LINEMODE);
1563                 ADD(LM_MODE);
1564                 ADD_DATA(editmode);
1565                 ADD(SE);
1566
1567                 ADD(SB);
1568                 ADD(TELOPT_LINEMODE);
1569                 ADD(LM_SLC);
1570                 start_slc(0);
1571                 send_slc();
1572                 len = end_slc(&cp);
1573                 for (cpe = cp + len; cp < cpe; cp++)
1574                         ADD_DATA(*cp);
1575                 ADD(SE);
1576         }
1577 #endif  /* LINEMODE */
1578
1579         ADD(IAC);
1580         ADD(SE);
1581
1582         output_datalen(statusbuf, ncp - statusbuf);
1583         netflush();     /* Send it on its way */
1584
1585         DIAG(TD_OPTIONS,
1586                 {printsub('>', statusbuf, ncp - statusbuf); netflush();});
1587 }
1588
1589 /*
1590  * This function appends data to nfrontp and advances nfrontp.
1591  * Returns the number of characters written altogether (the
1592  * buffer may have been flushed in the process).
1593  */
1594
1595 int
1596 output_data(const char *format, ...)
1597 {
1598         va_list args;
1599         int len;
1600         char *buf;
1601
1602         va_start(args, format);
1603         if ((len = vasprintf(&buf, format, args)) == -1) {
1604                 va_end(args);
1605                 return -1;
1606         }
1607         output_datalen(buf, len);
1608         va_end(args);
1609         free(buf);
1610         return (len);
1611 }
1612
1613 void
1614 output_datalen(const char *buf, int len)
1615 {
1616         int remaining, copied;
1617
1618         remaining = BUFSIZ - (nfrontp - netobuf);
1619         while (len > 0) {
1620                 /* Free up enough space if the room is too low*/
1621                 if ((len > BUFSIZ ? BUFSIZ : len) > remaining) {
1622                         netflush();
1623                         remaining = BUFSIZ - (nfrontp - netobuf);
1624                 }
1625
1626                 /* Copy out as much as will fit */
1627                 copied = remaining > len ? len : remaining;
1628                 memmove(nfrontp, buf, copied);
1629                 nfrontp += copied;
1630                 len -= copied;
1631                 remaining -= copied;
1632                 buf += copied;
1633         }
1634         return;
1635 }