1 /* $NetBSD: state.c,v 1.34 2024/02/10 09:21:52 andvar Exp $ */ 2 3 /* 4 * Copyright (c) 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 #ifndef lint 34 #if 0 35 static char sccsid[] = "@(#)state.c 8.5 (Berkeley) 5/30/95"; 36 #else 37 __RCSID("$NetBSD: state.c,v 1.34 2024/02/10 09:21:52 andvar Exp $"); 38 #endif 39 #endif /* not lint */ 40 41 #include <ctype.h> 42 #include <stdarg.h> 43 44 #include "telnetd.h" 45 46 static int envvarok(char *); 47 48 int not42 = 1; 49 50 /* 51 * Buffer for sub-options, and macros 52 * for suboptions buffer manipulations 53 */ 54 unsigned char subbuffer[4096], *subpointer= subbuffer, *subend= subbuffer; 55 56 #define SB_CLEAR() subpointer = subbuffer 57 #define SB_TERM() { subend = subpointer; SB_CLEAR(); } 58 #define SB_ACCUM(c) if (subpointer < (subbuffer+sizeof subbuffer)) { \ 59 *subpointer++ = (c); \ 60 } 61 #define SB_GET() ((*subpointer++)&0xff) 62 #define SB_EOF() (subpointer >= subend) 63 #define SB_LEN() (subend - subpointer) 64 65 #ifdef ENV_HACK 66 unsigned char *subsave; 67 #define SB_SAVE() subsave = subpointer; 68 #define SB_RESTORE() subpointer = subsave; 69 #endif 70 71 72 /* 73 * State for recv fsm 74 */ 75 #define TS_DATA 0 /* base state */ 76 #define TS_IAC 1 /* look for double IAC's */ 77 #define TS_CR 2 /* CR-LF ->'s CR */ 78 #define TS_SB 3 /* throw away begin's... */ 79 #define TS_SE 4 /* ...end's (suboption negotiation) */ 80 #define TS_WILL 5 /* will option negotiation */ 81 #define TS_WONT 6 /* wont " */ 82 #define TS_DO 7 /* do " */ 83 #define TS_DONT 8 /* dont " */ 84 85 void 86 telrcv(void) 87 { 88 int c; 89 static int state = TS_DATA; 90 91 while (ncc > 0) { 92 if ((&ptyobuf[BUFSIZ] - pfrontp) < 2) 93 break; 94 c = *netip++ & 0377, ncc--; 95 #ifdef ENCRYPTION 96 if (decrypt_input) 97 c = (*decrypt_input)(c); 98 #endif /* ENCRYPTION */ 99 switch (state) { 100 101 case TS_CR: 102 state = TS_DATA; 103 104 #ifdef LINEMODE 105 /* 106 * If we are operating in linemode, 107 * convert to local end-of-line. 108 */ 109 if (linemode && (ncc > 0) && ((c == '\n') || 110 ((c == 0) && tty_iscrnl())) ) 111 c = '\n'; 112 else 113 #endif 114 { 115 /* 116 * We now map \r\n ==> \r for pragmatic reasons. 117 * Many client implementations send \r\n when 118 * the user hits the CarriageReturn key. 119 * 120 * We USED to map \r\n ==> \n, since \r\n says 121 * that we want to be in column 1 of the next 122 * printable line, and \n is the standard 123 * unix way of saying that (\r is only good 124 * if CRMOD is set, which it normally is). 125 */ 126 127 /* Strip off \n or \0 after a \r */ 128 if ((c == 0) || (c == '\n')) 129 break; 130 } 131 /* FALL THROUGH */ 132 133 case TS_DATA: 134 if (c == IAC) { 135 state = TS_IAC; 136 break; 137 } 138 139 if ((c == '\r') && his_state_is_wont(TELOPT_BINARY)) 140 state = TS_CR; 141 142 *pfrontp++ = c; 143 break; 144 145 case TS_IAC: 146 gotiac: switch (c) { 147 148 /* 149 * Send the process on the pty side an 150 * interrupt. Do this with a NULL or 151 * interrupt char; depending on the tty mode. 152 */ 153 case IP: 154 DIAG(TD_OPTIONS, 155 printoption("td: recv IAC", c)); 156 interrupt(); 157 break; 158 159 case BREAK: 160 DIAG(TD_OPTIONS, 161 printoption("td: recv IAC", c)); 162 sendbrk(); 163 break; 164 165 /* 166 * Are You There? 167 */ 168 case AYT: 169 DIAG(TD_OPTIONS, 170 printoption("td: recv IAC", c)); 171 recv_ayt(); 172 break; 173 174 /* 175 * Abort Output 176 */ 177 case AO: 178 { 179 DIAG(TD_OPTIONS, 180 printoption("td: recv IAC", c)); 181 ptyflush(); /* half-hearted */ 182 init_termbuf(); 183 184 if (slctab[SLC_AO].sptr && 185 *slctab[SLC_AO].sptr != (cc_t)(_POSIX_VDISABLE)) { 186 *pfrontp++ = 187 (unsigned char)*slctab[SLC_AO].sptr; 188 } 189 190 netclear(); /* clear buffer back */ 191 output_data("%c%c", IAC, DM); 192 neturg = nfrontp - 1; /* off by one XXX */ 193 DIAG(TD_OPTIONS, 194 printoption("td: send IAC", DM)); 195 break; 196 } 197 198 /* 199 * Erase Character and 200 * Erase Line 201 */ 202 case EC: 203 case EL: 204 { 205 cc_t ch; 206 207 DIAG(TD_OPTIONS, 208 printoption("td: recv IAC", c)); 209 ptyflush(); /* half-hearted */ 210 init_termbuf(); 211 if (c == EC) 212 ch = *slctab[SLC_EC].sptr; 213 else 214 ch = *slctab[SLC_EL].sptr; 215 if (ch != (cc_t)(_POSIX_VDISABLE)) 216 *pfrontp++ = (unsigned char)ch; 217 break; 218 } 219 220 /* 221 * Check for urgent data... 222 */ 223 case DM: 224 DIAG(TD_OPTIONS, 225 printoption("td: recv IAC", c)); 226 SYNCHing = stilloob(net); 227 settimer(gotDM); 228 break; 229 230 231 /* 232 * Begin option subnegotiation... 233 */ 234 case SB: 235 state = TS_SB; 236 SB_CLEAR(); 237 continue; 238 239 case WILL: 240 state = TS_WILL; 241 continue; 242 243 case WONT: 244 state = TS_WONT; 245 continue; 246 247 case DO: 248 state = TS_DO; 249 continue; 250 251 case DONT: 252 state = TS_DONT; 253 continue; 254 case EOR: 255 if (his_state_is_will(TELOPT_EOR)) 256 doeof(); 257 break; 258 259 /* 260 * Handle RFC 10xx Telnet linemode option additions 261 * to command stream (EOF, SUSP, ABORT). 262 */ 263 case xEOF: 264 doeof(); 265 break; 266 267 case SUSP: 268 sendsusp(); 269 break; 270 271 case ABORT: 272 sendbrk(); 273 break; 274 275 case IAC: 276 *pfrontp++ = c; 277 break; 278 } 279 state = TS_DATA; 280 break; 281 282 case TS_SB: 283 if (c == IAC) { 284 state = TS_SE; 285 } else { 286 SB_ACCUM(c); 287 } 288 break; 289 290 case TS_SE: 291 if (c != SE) { 292 if (c != IAC) { 293 /* 294 * bad form of suboption negotiation. 295 * handle it in such a way as to avoid 296 * damage to local state. Parse 297 * suboption buffer found so far, 298 * then treat remaining stream as 299 * another command sequence. 300 */ 301 302 /* for DIAGNOSTICS */ 303 SB_ACCUM(IAC); 304 SB_ACCUM(c); 305 subpointer -= 2; 306 307 SB_TERM(); 308 suboption(); 309 state = TS_IAC; 310 goto gotiac; 311 } 312 SB_ACCUM(c); 313 state = TS_SB; 314 } else { 315 /* for DIAGNOSTICS */ 316 SB_ACCUM(IAC); 317 SB_ACCUM(SE); 318 subpointer -= 2; 319 320 SB_TERM(); 321 suboption(); /* handle sub-option */ 322 state = TS_DATA; 323 } 324 break; 325 326 case TS_WILL: 327 willoption(c); 328 state = TS_DATA; 329 continue; 330 331 case TS_WONT: 332 wontoption(c); 333 state = TS_DATA; 334 continue; 335 336 case TS_DO: 337 dooption(c); 338 state = TS_DATA; 339 continue; 340 341 case TS_DONT: 342 dontoption(c); 343 state = TS_DATA; 344 continue; 345 346 default: 347 syslog(LOG_ERR, "panic state=%d", state); 348 printf("telnetd: panic state=%d\n", state); 349 exit(1); 350 } 351 } 352 } /* end of telrcv */ 353 354 /* 355 * The will/wont/do/dont state machines are based on Dave Borman's 356 * Telnet option processing state machine. 357 * 358 * These correspond to the following states: 359 * my_state = the last negotiated state 360 * want_state = what I want the state to go to 361 * want_resp = how many requests I have sent 362 * All state defaults are negative, and resp defaults to 0. 363 * 364 * When initiating a request to change state to new_state: 365 * 366 * if ((want_resp == 0 && new_state == my_state) || want_state == new_state) { 367 * do nothing; 368 * } else { 369 * want_state = new_state; 370 * send new_state; 371 * want_resp++; 372 * } 373 * 374 * When receiving new_state: 375 * 376 * if (want_resp) { 377 * want_resp--; 378 * if (want_resp && (new_state == my_state)) 379 * want_resp--; 380 * } 381 * if ((want_resp == 0) && (new_state != want_state)) { 382 * if (ok_to_switch_to new_state) 383 * want_state = new_state; 384 * else 385 * want_resp++; 386 * send want_state; 387 * } 388 * my_state = new_state; 389 * 390 * Note that new_state is implied in these functions by the function itself. 391 * will and do imply positive new_state, wont and dont imply negative. 392 * 393 * Finally, there is one catch. If we send a negative response to a 394 * positive request, my_state will be the positive while want_state will 395 * remain negative. my_state will revert to negative when the negative 396 * acknowledgment arrives from the peer. Thus, my_state generally tells 397 * us not only the last negotiated state, but also tells us what the peer 398 * wants to be doing as well. It is important to understand this difference 399 * as we may wish to be processing data streams based on our desired state 400 * (want_state) or based on what the peer thinks the state is (my_state). 401 * 402 * This all works fine because if the peer sends a positive request, the data 403 * that we receive prior to negative acknowledgment will probably be affected 404 * by the positive state, and we can process it as such (if we can; if we 405 * can't then it really doesn't matter). If it is that important, then the 406 * peer probably should be buffering until this option state negotiation 407 * is complete. 408 * 409 */ 410 void 411 send_do(int option, int init) 412 { 413 if (init) { 414 if ((do_dont_resp[option] == 0 && his_state_is_will(option)) || 415 his_want_state_is_will(option)) 416 return; 417 /* 418 * Special case for TELOPT_TM: We send a DO, but pretend 419 * that we sent a DONT, so that we can send more DOs if 420 * we want to. 421 */ 422 if (option == TELOPT_TM) 423 set_his_want_state_wont(option); 424 else 425 set_his_want_state_will(option); 426 do_dont_resp[option]++; 427 } 428 (void) output_data("%c%c%c", IAC, DO, option); 429 430 DIAG(TD_OPTIONS, printoption("td: send do", option)); 431 } 432 433 #ifdef LINEMODE 434 extern void doclientstat(void); 435 #endif 436 #if 0 437 #ifdef AUTHENTICATION 438 extern void auth_request(void); /* libtelnet */ 439 #endif 440 #ifdef ENCRYPTION 441 extern void encrypt_send_support(void); 442 #endif /* ENCRYPTION */ 443 #endif 444 445 void 446 willoption(int option) 447 { 448 int changeok = 0; 449 void (*func)(void) = 0; 450 451 /* 452 * process input from peer. 453 */ 454 455 DIAG(TD_OPTIONS, printoption("td: recv will", option)); 456 457 if (do_dont_resp[option]) { 458 do_dont_resp[option]--; 459 if (do_dont_resp[option] && his_state_is_will(option)) 460 do_dont_resp[option]--; 461 } 462 if (do_dont_resp[option] == 0) { 463 if (his_want_state_is_wont(option)) { 464 switch (option) { 465 466 case TELOPT_BINARY: 467 init_termbuf(); 468 tty_binaryin(1); 469 set_termbuf(); 470 changeok++; 471 break; 472 473 case TELOPT_ECHO: 474 /* 475 * See comments below for more info. 476 */ 477 not42 = 0; /* looks like a 4.2 system */ 478 break; 479 480 case TELOPT_TM: 481 #if defined(LINEMODE) && defined(KLUDGELINEMODE) 482 /* 483 * This telnetd implementation does not really 484 * support timing marks, it just uses them to 485 * support the kludge linemode stuff. If we 486 * receive a will or wont TM in response to our 487 * do TM request that may have been sent to 488 * determine kludge linemode support, process 489 * it, otherwise TM should get a negative 490 * response back. 491 */ 492 /* 493 * Handle the linemode kludge stuff. 494 * If we are not currently supporting any 495 * linemode at all, then we assume that this 496 * is the client telling us to use kludge 497 * linemode in response to our query. Set the 498 * linemode type that is to be supported, note 499 * that the client wishes to use linemode, and 500 * eat the will TM as though it never arrived. 501 */ 502 if (lmodetype < KLUDGE_LINEMODE) { 503 lmodetype = KLUDGE_LINEMODE; 504 clientstat(TELOPT_LINEMODE, WILL, 0); 505 send_wont(TELOPT_SGA, 1); 506 } else if (lmodetype == NO_AUTOKLUDGE) { 507 lmodetype = KLUDGE_OK; 508 } 509 #endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */ 510 /* 511 * We never respond to a WILL TM, and 512 * we leave the state WONT. 513 */ 514 return; 515 516 case TELOPT_LFLOW: 517 /* 518 * If we are going to support flow control 519 * option, then don't worry peer that we can't 520 * change the flow control characters. 521 */ 522 slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS; 523 slctab[SLC_XON].defset.flag |= SLC_DEFAULT; 524 slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS; 525 slctab[SLC_XOFF].defset.flag |= SLC_DEFAULT; 526 /* FALLTHROUGH */ 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 func = auth_request; 553 changeok++; 554 break; 555 #endif 556 557 #ifdef ENCRYPTION 558 case TELOPT_ENCRYPT: 559 func = encrypt_send_support; 560 changeok++; 561 break; 562 #endif /* ENCRYPTION */ 563 564 default: 565 break; 566 } 567 if (changeok) { 568 set_his_want_state_will(option); 569 send_do(option, 0); 570 } else { 571 do_dont_resp[option]++; 572 send_dont(option, 0); 573 } 574 } else { 575 /* 576 * Option processing that should happen when 577 * we receive conformation of a change in 578 * state that we had requested. 579 */ 580 switch (option) { 581 case TELOPT_ECHO: 582 not42 = 0; /* looks like a 4.2 system */ 583 /* 584 * Egads, he responded "WILL ECHO". Turn 585 * it off right now! 586 */ 587 send_dont(option, 1); 588 /* 589 * "WILL ECHO". Kludge upon kludge! 590 * A 4.2 client is now echoing user input at 591 * the tty. This is probably undesireable and 592 * it should be stopped. The client will 593 * respond WONT TM to the DO TM that we send to 594 * check for kludge linemode. When the WONT TM 595 * arrives, linemode will be turned off and a 596 * change propagated to the pty. This change 597 * will cause us to process the new pty state 598 * in localstat(), which will notice that 599 * linemode is off and send a WILL ECHO 600 * so that we are properly in character mode and 601 * all is well. 602 */ 603 break; 604 #ifdef LINEMODE 605 case TELOPT_LINEMODE: 606 # ifdef KLUDGELINEMODE 607 /* 608 * Note client's desire to use linemode. 609 */ 610 lmodetype = REAL_LINEMODE; 611 # endif /* KLUDGELINEMODE */ 612 func = doclientstat; 613 break; 614 #endif /* LINEMODE */ 615 616 #ifdef AUTHENTICATION 617 case TELOPT_AUTHENTICATION: 618 func = auth_request; 619 break; 620 #endif 621 622 #ifdef ENCRYPTION 623 case TELOPT_ENCRYPT: 624 func = encrypt_send_support; 625 break; 626 #endif /* ENCRYPTION */ 627 628 case TELOPT_LFLOW: 629 func = flowstat; 630 break; 631 } 632 } 633 } 634 set_his_state_will(option); 635 if (func) 636 (*func)(); 637 } /* end of willoption */ 638 639 void 640 send_dont(int option, int init) 641 { 642 if (init) { 643 if ((do_dont_resp[option] == 0 && his_state_is_wont(option)) || 644 his_want_state_is_wont(option)) 645 return; 646 set_his_want_state_wont(option); 647 do_dont_resp[option]++; 648 } 649 (void) output_data("%c%c%c", IAC, DONT, option); 650 651 DIAG(TD_OPTIONS, printoption("td: send dont", option)); 652 } 653 654 void 655 wontoption(int option) 656 { 657 /* 658 * Process client input. 659 */ 660 661 DIAG(TD_OPTIONS, printoption("td: recv wont", option)); 662 663 if (do_dont_resp[option]) { 664 do_dont_resp[option]--; 665 if (do_dont_resp[option] && his_state_is_wont(option)) 666 do_dont_resp[option]--; 667 } 668 if (do_dont_resp[option] == 0) { 669 if (his_want_state_is_will(option)) { 670 /* it is always ok to change to negative state */ 671 switch (option) { 672 case TELOPT_ECHO: 673 not42 = 1; /* doesn't seem to be a 4.2 system */ 674 break; 675 676 case TELOPT_BINARY: 677 init_termbuf(); 678 tty_binaryin(0); 679 set_termbuf(); 680 break; 681 682 #ifdef LINEMODE 683 case TELOPT_LINEMODE: 684 # ifdef KLUDGELINEMODE 685 /* 686 * If real linemode is supported, then client is 687 * asking to turn linemode off. 688 */ 689 if (lmodetype != REAL_LINEMODE) 690 break; 691 /* XXX double-check this --thorpej */ 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 * achieve 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 (void) output_data("%c%c%c", IAC, 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 */ 918 919 case TELOPT_LINEMODE: 920 case TELOPT_TTYPE: 921 case TELOPT_NAWS: 922 case TELOPT_TSPEED: 923 case TELOPT_LFLOW: 924 case TELOPT_XDISPLOC: 925 case TELOPT_OLD_ENVIRON: 926 default: 927 break; 928 } 929 if (changeok) { 930 set_my_want_state_will(option); 931 send_will(option, 0); 932 } else { 933 will_wont_resp[option]++; 934 send_wont(option, 0); 935 } 936 } 937 set_my_state_will(option); 938 939 } /* end of dooption */ 940 941 void 942 send_wont(int option, int init) 943 { 944 if (init) { 945 if ((will_wont_resp[option] == 0 && my_state_is_wont(option)) || 946 my_want_state_is_wont(option)) 947 return; 948 set_my_want_state_wont(option); 949 will_wont_resp[option]++; 950 } 951 (void) output_data("%c%c%c", IAC, WONT, option); 952 953 DIAG(TD_OPTIONS, printoption("td: send wont", option)); 954 } 955 956 void 957 dontoption(int option) 958 { 959 /* 960 * Process client input. 961 */ 962 963 964 DIAG(TD_OPTIONS, printoption("td: recv dont", option)); 965 966 if (will_wont_resp[option]) { 967 will_wont_resp[option]--; 968 if (will_wont_resp[option] && my_state_is_wont(option)) 969 will_wont_resp[option]--; 970 } 971 if ((will_wont_resp[option] == 0) && (my_want_state_is_will(option))) { 972 switch (option) { 973 case TELOPT_BINARY: 974 init_termbuf(); 975 tty_binaryout(0); 976 set_termbuf(); 977 break; 978 979 case TELOPT_ECHO: /* we should stop echoing */ 980 #ifdef LINEMODE 981 # ifdef KLUDGELINEMODE 982 if ((lmodetype != REAL_LINEMODE) && 983 (lmodetype != KLUDGE_LINEMODE)) 984 # else 985 if (his_state_is_wont(TELOPT_LINEMODE)) 986 # endif 987 #endif 988 { 989 init_termbuf(); 990 tty_setecho(0); 991 set_termbuf(); 992 } 993 break; 994 995 case TELOPT_SGA: 996 #if defined(LINEMODE) && defined(KLUDGELINEMODE) 997 /* 998 * If kludge linemode is in use, then we 999 * must process an incoming do SGA for 1000 * linemode purposes. 1001 */ 1002 if ((lmodetype == KLUDGE_LINEMODE) || 1003 (lmodetype == KLUDGE_OK)) { 1004 /* 1005 * The client is asking us to turn 1006 * linemode on. 1007 */ 1008 lmodetype = KLUDGE_LINEMODE; 1009 clientstat(TELOPT_LINEMODE, WILL, 0); 1010 /* 1011 * If we did not turn line mode on, 1012 * then what do we say? Will SGA? 1013 * This violates design of telnet. 1014 * Gross. Very Gross. 1015 */ 1016 } 1017 break; 1018 #else 1019 set_my_want_state_wont(option); 1020 if (my_state_is_will(option)) 1021 send_wont(option, 0); 1022 set_my_state_wont(option); 1023 if (turn_on_sga ^= 1) 1024 send_will(option, 1); 1025 return; 1026 #endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */ 1027 1028 default: 1029 break; 1030 } 1031 1032 set_my_want_state_wont(option); 1033 if (my_state_is_will(option)) 1034 send_wont(option, 0); 1035 } 1036 set_my_state_wont(option); 1037 1038 } /* end of dontoption */ 1039 1040 #ifdef ENV_HACK 1041 int env_ovar = -1; 1042 int env_ovalue = -1; 1043 #else /* ENV_HACK */ 1044 # define env_ovar OLD_ENV_VAR 1045 # define env_ovalue OLD_ENV_VALUE 1046 #endif /* ENV_HACK */ 1047 1048 /* envvarok(char*) */ 1049 /* check that variable is safe to pass to login or shell */ 1050 static int 1051 envvarok(char *varp) 1052 { 1053 1054 if (strcmp(varp, "TERMCAP") && /* to prevent a security hole */ 1055 strcmp(varp, "TERMINFO") && /* with tgetent */ 1056 strcmp(varp, "TERMPATH") && 1057 strcmp(varp, "HOME") && /* to prevent the tegetent bug */ 1058 strncmp(varp, "LD_", strlen("LD_")) && /* most systems */ 1059 strncmp(varp, "_RLD_", strlen("_RLD_")) && /* IRIX */ 1060 strcmp(varp, "LIBPATH") && /* AIX */ 1061 strcmp(varp, "ENV") && 1062 strcmp(varp, "BASH_ENV") && 1063 strcmp(varp, "IFS") && 1064 strncmp(varp, "KRB5", strlen("KRB5")) && /* Krb5 */ 1065 /* 1066 * The above case is a catch-all for now. Here are some of 1067 * the specific ones we must avoid passing, at least until 1068 * we can prove it can be done safely. Keep this list 1069 * around un case someone wants to remove the catch-all. 1070 */ 1071 strcmp(varp, "KRB5_CONFIG") && /* Krb5 */ 1072 strcmp(varp, "KRB5CCNAME") && /* Krb5 */ 1073 strcmp(varp, "KRB5_KTNAME") && /* Krb5 */ 1074 strcmp(varp, "KRBTKFILE") && /* Krb4 */ 1075 strcmp(varp, "KRB_CONF") && /* CNS 4 */ 1076 strcmp(varp, "KRB_REALMS") && /* CNS 4 */ 1077 strcmp(varp, "RESOLV_HOST_CONF")) /* Linux */ 1078 return (1); 1079 else { 1080 syslog(LOG_INFO, "Rejected the attempt to modify the " 1081 "environment variable \"%s\"", varp); 1082 return (0); 1083 } 1084 } 1085 1086 /* 1087 * suboption() 1088 * 1089 * Look at the sub-option buffer, and try to be helpful to the other 1090 * side. 1091 * 1092 * Currently we recognize: 1093 * 1094 * Terminal type is 1095 * Linemode 1096 * Window size 1097 * Terminal speed 1098 */ 1099 void 1100 suboption(void) 1101 { 1102 int subchar; 1103 1104 DIAG(TD_OPTIONS, {netflush(); printsub('<', subpointer, SB_LEN()+2);}); 1105 1106 subchar = SB_GET(); 1107 switch (subchar) { 1108 case TELOPT_TSPEED: { 1109 int xspeed, rspeed; 1110 1111 if (his_state_is_wont(TELOPT_TSPEED)) /* Ignore if option disabled */ 1112 break; 1113 1114 settimer(tspeedsubopt); 1115 1116 if (SB_EOF() || SB_GET() != TELQUAL_IS) 1117 return; 1118 1119 xspeed = atoi((char *)subpointer); 1120 1121 while (SB_GET() != ',' && !SB_EOF()); 1122 if (SB_EOF()) 1123 return; 1124 1125 rspeed = atoi((char *)subpointer); 1126 clientstat(TELOPT_TSPEED, xspeed, rspeed); 1127 1128 break; 1129 1130 } /* end of case TELOPT_TSPEED */ 1131 1132 case TELOPT_TTYPE: { /* Yaaaay! */ 1133 char *p; 1134 1135 if (his_state_is_wont(TELOPT_TTYPE)) /* Ignore if option disabled */ 1136 break; 1137 settimer(ttypesubopt); 1138 1139 if (SB_EOF() || SB_GET() != TELQUAL_IS) { 1140 return; /* ??? XXX but, this is the most robust */ 1141 } 1142 1143 p = terminaltype; 1144 1145 while ((p < (terminaltype + sizeof terminaltype-1)) && 1146 !SB_EOF()) { 1147 int c; 1148 1149 c = SB_GET(); 1150 if (isupper(c)) { 1151 c = tolower(c); 1152 } 1153 *p++ = c; /* accumulate name */ 1154 } 1155 *p = 0; 1156 break; 1157 } /* end of case TELOPT_TTYPE */ 1158 1159 case TELOPT_NAWS: { 1160 int xwinsize, ywinsize; 1161 1162 if (his_state_is_wont(TELOPT_NAWS)) /* Ignore if option disabled */ 1163 break; 1164 1165 if (SB_EOF()) 1166 return; 1167 xwinsize = SB_GET() << 8; 1168 if (SB_EOF()) 1169 return; 1170 xwinsize |= SB_GET(); 1171 if (SB_EOF()) 1172 return; 1173 ywinsize = SB_GET() << 8; 1174 if (SB_EOF()) 1175 return; 1176 ywinsize |= SB_GET(); 1177 clientstat(TELOPT_NAWS, xwinsize, ywinsize); 1178 1179 break; 1180 1181 } /* end of case TELOPT_NAWS */ 1182 1183 #ifdef LINEMODE 1184 case TELOPT_LINEMODE: { 1185 int request; 1186 1187 if (his_state_is_wont(TELOPT_LINEMODE)) /* Ignore if option disabled */ 1188 break; 1189 /* 1190 * Process linemode suboptions. 1191 */ 1192 if (SB_EOF()) 1193 break; /* garbage was sent */ 1194 request = SB_GET(); /* get will/wont */ 1195 1196 if (SB_EOF()) 1197 break; /* another garbage check */ 1198 1199 if (request == LM_SLC) { /* SLC is not preceded by WILL or WONT */ 1200 /* 1201 * Process suboption buffer of slc's 1202 */ 1203 start_slc(1); 1204 do_opt_slc(subpointer, SB_LEN()); 1205 (void) end_slc(0); 1206 break; 1207 } else if (request == LM_MODE) { 1208 if (SB_EOF()) 1209 return; 1210 useeditmode = SB_GET(); /* get mode flag */ 1211 clientstat(LM_MODE, 0, 0); 1212 break; 1213 } 1214 1215 if (SB_EOF()) 1216 break; 1217 switch (SB_GET()) { /* what suboption? */ 1218 case LM_FORWARDMASK: 1219 /* 1220 * According to spec, only server can send request for 1221 * forwardmask, and client can only return a positive response. 1222 * So don't worry about it. 1223 */ 1224 1225 default: 1226 break; 1227 } 1228 break; 1229 } /* end of case TELOPT_LINEMODE */ 1230 #endif 1231 case TELOPT_STATUS: { 1232 int mode; 1233 1234 if (SB_EOF()) 1235 break; 1236 mode = SB_GET(); 1237 switch (mode) { 1238 case TELQUAL_SEND: 1239 if (my_state_is_will(TELOPT_STATUS)) 1240 send_status(); 1241 break; 1242 1243 case TELQUAL_IS: 1244 break; 1245 1246 default: 1247 break; 1248 } 1249 break; 1250 } /* end of case TELOPT_STATUS */ 1251 1252 case TELOPT_XDISPLOC: { 1253 if (SB_EOF() || SB_GET() != TELQUAL_IS) 1254 return; 1255 settimer(xdisplocsubopt); 1256 subpointer[SB_LEN()] = '\0'; 1257 (void)setenv("DISPLAY", (char *)subpointer, 1); 1258 break; 1259 } /* end of case TELOPT_XDISPLOC */ 1260 1261 case TELOPT_NEW_ENVIRON: 1262 case TELOPT_OLD_ENVIRON: { 1263 int c; 1264 char *cp, *varp, *valp; 1265 1266 if (SB_EOF()) 1267 return; 1268 c = SB_GET(); 1269 if (c == TELQUAL_IS) { 1270 if (subchar == TELOPT_OLD_ENVIRON) 1271 settimer(oenvironsubopt); 1272 else 1273 settimer(environsubopt); 1274 } else if (c != TELQUAL_INFO) { 1275 return; 1276 } 1277 1278 if (subchar == TELOPT_NEW_ENVIRON) { 1279 while (!SB_EOF()) { 1280 c = SB_GET(); 1281 if ((c == NEW_ENV_VAR) || (c == ENV_USERVAR)) 1282 break; 1283 } 1284 } else 1285 { 1286 #ifdef ENV_HACK 1287 /* 1288 * We only want to do this if we haven't already decided 1289 * whether or not the other side has its VALUE and VAR 1290 * reversed. 1291 */ 1292 if (env_ovar < 0) { 1293 int last = -1; /* invalid value */ 1294 int empty = 0; 1295 int got_var = 0, got_value = 0, got_uservar = 0; 1296 1297 /* 1298 * The other side might have its VALUE and VAR values 1299 * reversed. To be interoperable, we need to determine 1300 * which way it is. If the first recognized character 1301 * is a VAR or VALUE, then that will tell us what 1302 * type of client it is. If the first recognized 1303 * character is a USERVAR, then we continue scanning 1304 * the suboption looking for two consecutive 1305 * VAR or VALUE fields. We should not get two 1306 * consecutive VALUE fields, so finding two 1307 * consecutive VALUE or VAR fields will tell us 1308 * what the client is. 1309 */ 1310 SB_SAVE(); 1311 while (!SB_EOF()) { 1312 c = SB_GET(); 1313 switch(c) { 1314 case OLD_ENV_VAR: 1315 if (last < 0 || last == OLD_ENV_VAR 1316 || (empty && (last == OLD_ENV_VALUE))) 1317 goto env_ovar_ok; 1318 got_var++; 1319 last = OLD_ENV_VAR; 1320 break; 1321 case OLD_ENV_VALUE: 1322 if (last < 0 || last == OLD_ENV_VALUE 1323 || (empty && (last == OLD_ENV_VAR))) 1324 goto env_ovar_wrong; 1325 got_value++; 1326 last = OLD_ENV_VALUE; 1327 break; 1328 case ENV_USERVAR: 1329 /* count strings of USERVAR as one */ 1330 if (last != ENV_USERVAR) 1331 got_uservar++; 1332 if (empty) { 1333 if (last == OLD_ENV_VALUE) 1334 goto env_ovar_ok; 1335 if (last == OLD_ENV_VAR) 1336 goto env_ovar_wrong; 1337 } 1338 last = ENV_USERVAR; 1339 break; 1340 case ENV_ESC: 1341 if (!SB_EOF()) 1342 c = SB_GET(); 1343 /* FALL THROUGH */ 1344 default: 1345 empty = 0; 1346 continue; 1347 } 1348 empty = 1; 1349 } 1350 if (empty) { 1351 if (last == OLD_ENV_VALUE) 1352 goto env_ovar_ok; 1353 if (last == OLD_ENV_VAR) 1354 goto env_ovar_wrong; 1355 } 1356 /* 1357 * Ok, the first thing was a USERVAR, and there 1358 * are not two consecutive VAR or VALUE commands, 1359 * and none of the VAR or VALUE commands are empty. 1360 * If the client has sent us a well-formed option, 1361 * then the number of VALUEs received should always 1362 * be less than or equal to the number of VARs and 1363 * USERVARs received. 1364 * 1365 * If we got exactly as many VALUEs as VARs and 1366 * USERVARs, the client has the same definitions. 1367 * 1368 * If we got exactly as many VARs as VALUEs and 1369 * USERVARS, the client has reversed definitions. 1370 */ 1371 if (got_uservar + got_var == got_value) { 1372 env_ovar_ok: 1373 env_ovar = OLD_ENV_VAR; 1374 env_ovalue = OLD_ENV_VALUE; 1375 } else if (got_uservar + got_value == got_var) { 1376 env_ovar_wrong: 1377 env_ovar = OLD_ENV_VALUE; 1378 env_ovalue = OLD_ENV_VAR; 1379 DIAG(TD_OPTIONS, {output_data( 1380 "ENVIRON VALUE and VAR are reversed!\r\n");}); 1381 1382 } 1383 } 1384 SB_RESTORE(); 1385 #endif 1386 1387 while (!SB_EOF()) { 1388 c = SB_GET(); 1389 if ((c == env_ovar) || (c == ENV_USERVAR)) 1390 break; 1391 } 1392 } 1393 1394 if (SB_EOF()) 1395 return; 1396 1397 cp = varp = (char *)subpointer; 1398 valp = 0; 1399 1400 while (!SB_EOF()) { 1401 c = SB_GET(); 1402 if (subchar == TELOPT_OLD_ENVIRON) { 1403 if (c == env_ovar) 1404 c = NEW_ENV_VAR; 1405 else if (c == env_ovalue) 1406 c = NEW_ENV_VALUE; 1407 } 1408 switch (c) { 1409 1410 case NEW_ENV_VALUE: 1411 *cp = '\0'; 1412 cp = valp = (char *)subpointer; 1413 break; 1414 1415 case NEW_ENV_VAR: 1416 case ENV_USERVAR: 1417 *cp = '\0'; 1418 if (envvarok(varp)) { 1419 if (valp) 1420 (void)setenv(varp, valp, 1); 1421 else 1422 unsetenv(varp); 1423 } 1424 cp = varp = (char *)subpointer; 1425 valp = 0; 1426 break; 1427 1428 case ENV_ESC: 1429 if (SB_EOF()) 1430 break; 1431 c = SB_GET(); 1432 /* FALL THROUGH */ 1433 default: 1434 *cp++ = c; 1435 break; 1436 } 1437 } 1438 *cp = '\0'; 1439 if (envvarok(varp)) { 1440 if (valp) 1441 (void)setenv(varp, valp, 1); 1442 else 1443 unsetenv(varp); 1444 } 1445 break; 1446 } /* end of case TELOPT_NEW_ENVIRON */ 1447 #ifdef AUTHENTICATION 1448 case TELOPT_AUTHENTICATION: 1449 if (SB_EOF()) 1450 break; 1451 switch(SB_GET()) { 1452 case TELQUAL_SEND: 1453 case TELQUAL_REPLY: 1454 /* 1455 * These are sent by us and cannot be sent by 1456 * the client. 1457 */ 1458 break; 1459 case TELQUAL_IS: 1460 auth_is(subpointer, SB_LEN()); 1461 break; 1462 case TELQUAL_NAME: 1463 auth_name(subpointer, SB_LEN()); 1464 break; 1465 } 1466 break; 1467 #endif 1468 #ifdef ENCRYPTION 1469 case TELOPT_ENCRYPT: 1470 if (SB_EOF()) 1471 break; 1472 switch(SB_GET()) { 1473 case ENCRYPT_SUPPORT: 1474 encrypt_support(subpointer, SB_LEN()); 1475 break; 1476 case ENCRYPT_IS: 1477 encrypt_is(subpointer, SB_LEN()); 1478 break; 1479 case ENCRYPT_REPLY: 1480 encrypt_reply(subpointer, SB_LEN()); 1481 break; 1482 case ENCRYPT_START: 1483 encrypt_start(subpointer, SB_LEN()); 1484 break; 1485 case ENCRYPT_END: 1486 encrypt_end(); 1487 break; 1488 case ENCRYPT_REQSTART: 1489 encrypt_request_start(subpointer, SB_LEN()); 1490 break; 1491 case ENCRYPT_REQEND: 1492 /* 1493 * We can always send an REQEND so that we cannot 1494 * get stuck encrypting. We should only get this 1495 * if we have been able to get in the correct mode 1496 * anyhow. 1497 */ 1498 encrypt_request_end(); 1499 break; 1500 case ENCRYPT_ENC_KEYID: 1501 encrypt_enc_keyid(subpointer, SB_LEN()); 1502 break; 1503 case ENCRYPT_DEC_KEYID: 1504 encrypt_dec_keyid(subpointer, SB_LEN()); 1505 break; 1506 default: 1507 break; 1508 } 1509 break; 1510 #endif /* ENCRYPTION */ 1511 1512 default: 1513 break; 1514 } /* end of switch */ 1515 1516 } /* end of suboption */ 1517 1518 #ifdef LINEMODE 1519 void 1520 doclientstat(void) 1521 { 1522 clientstat(TELOPT_LINEMODE, WILL, 0); 1523 } 1524 #endif /* LINEMODE */ 1525 1526 void 1527 send_status(void) 1528 { 1529 #define ADD(c) \ 1530 do { \ 1531 if (ep > ncp) \ 1532 *ncp++ = c; \ 1533 else \ 1534 goto trunc; \ 1535 } while (0) 1536 #define ADD_DATA(c) \ 1537 do { \ 1538 ADD(c); if (c == SE || c == IAC) ADD(c); \ 1539 } while (0) 1540 1541 unsigned char statusbuf[256]; 1542 unsigned char *ep; 1543 unsigned char *ncp; 1544 unsigned char i; 1545 1546 ncp = statusbuf; 1547 ep = statusbuf + sizeof(statusbuf); 1548 1549 netflush(); /* get rid of anything waiting to go out */ 1550 1551 ADD(IAC); 1552 ADD(SB); 1553 ADD(TELOPT_STATUS); 1554 ADD(TELQUAL_IS); 1555 1556 /* 1557 * We check the want_state rather than the current state, 1558 * because if we received a DO/WILL for an option that we 1559 * don't support, and the other side didn't send a DONT/WONT 1560 * in response to our WONT/DONT, then the "state" will be 1561 * WILL/DO, and the "want_state" will be WONT/DONT. We 1562 * need to go by the latter. 1563 */ 1564 for (i = 0; i < (unsigned char)NTELOPTS; i++) { 1565 if (my_want_state_is_will(i)) { 1566 ADD(WILL); 1567 ADD_DATA(i); 1568 } 1569 if (his_want_state_is_will(i)) { 1570 ADD(DO); 1571 ADD_DATA(i); 1572 } 1573 } 1574 1575 if (his_want_state_is_will(TELOPT_LFLOW)) { 1576 ADD(SB); 1577 ADD(TELOPT_LFLOW); 1578 if (flowmode) { 1579 ADD(LFLOW_ON); 1580 } else { 1581 ADD(LFLOW_OFF); 1582 } 1583 ADD(SE); 1584 1585 if (restartany >= 0) { 1586 ADD(SB); 1587 ADD(TELOPT_LFLOW); 1588 if (restartany) { 1589 ADD(LFLOW_RESTART_ANY); 1590 } else { 1591 ADD(LFLOW_RESTART_XON); 1592 } 1593 ADD(SE); 1594 } 1595 } 1596 1597 #ifdef LINEMODE 1598 if (his_want_state_is_will(TELOPT_LINEMODE)) { 1599 unsigned char *cp, *cpe; 1600 int len; 1601 1602 ADD(SB); 1603 ADD(TELOPT_LINEMODE); 1604 ADD(LM_MODE); 1605 ADD_DATA(editmode); 1606 ADD(SE); 1607 1608 ADD(SB); 1609 ADD(TELOPT_LINEMODE); 1610 ADD(LM_SLC); 1611 start_slc(0); 1612 send_slc(); 1613 len = end_slc(&cp); 1614 for (cpe = cp + len; cp < cpe; cp++) 1615 ADD_DATA(*cp); 1616 ADD(SE); 1617 } 1618 #endif /* LINEMODE */ 1619 1620 ADD(IAC); 1621 ADD(SE); 1622 1623 writenet(statusbuf, ncp - statusbuf); 1624 netflush(); /* Send it on its way */ 1625 1626 DIAG(TD_OPTIONS, 1627 {printsub('>', statusbuf, ncp - statusbuf); netflush();}); 1628 return; 1629 1630 trunc: 1631 /* XXX bark? */ 1632 return; 1633 #undef ADD 1634 #undef ADD_DATA 1635 } 1636 1637 int 1638 output_data(const char *format, ...) 1639 { 1640 va_list args; 1641 size_t remaining, ret; 1642 1643 va_start(args, format); 1644 remaining = BUFSIZ - (nfrontp - netobuf); 1645 /* try a netflush() if the room is too low */ 1646 if (strlen(format) > remaining || BUFSIZ / 4 > remaining) { 1647 netflush(); 1648 remaining = BUFSIZ - (nfrontp - netobuf); 1649 } 1650 ret = vsnprintf(nfrontp, remaining, format, args); 1651 nfrontp += ((ret < remaining - 1) ? ret : remaining - 1); 1652 va_end(args); 1653 return ret; 1654 } 1655 1656 int 1657 output_datalen(const char *buf, size_t l) 1658 { 1659 size_t remaining; 1660 1661 remaining = BUFSIZ - (nfrontp - netobuf); 1662 if (remaining < l) { 1663 netflush(); 1664 remaining = BUFSIZ - (nfrontp - netobuf); 1665 } 1666 if (remaining < l) 1667 return -1; 1668 memmove(nfrontp, buf, l); 1669 nfrontp += l; 1670 return (int)l; 1671 } 1672