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 36static const char sccsid[] = "@(#)state.c 8.5 (Berkeley) 5/30/95"; 37#endif 38#endif 39#include <sys/cdefs.h> 40__FBSDID("$FreeBSD: src/contrib/telnet/telnetd/state.c,v 1.14 2003/05/04 02:54:49 obrien Exp $"); 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 51unsigned char doopt[] = { IAC, DO, '%', 'c', 0 }; 52unsigned char dont[] = { IAC, DONT, '%', 'c', 0 }; 53unsigned char will[] = { IAC, WILL, '%', 'c', 0 }; 54unsigned char wont[] = { IAC, WONT, '%', 'c', 0 }; 55int not42 = 1; 56 57/* 58 * Buffer for sub-options, and macros 59 * for suboptions buffer manipulations 60 */ 61unsigned 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 73unsigned 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 92static void doclientstat(void); 93 94void 95telrcv(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: 163gotiac: 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 */ 427void 428send_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 450void 451willoption(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 func = auth_request; 557 changeok++; 558 break; 559#endif 560 561#ifdef ENCRYPTION 562 case TELOPT_ENCRYPT: 563 func = encrypt_send_support; 564 changeok++; 565 break; 566#endif /* ENCRYPTION */ 567 568 default: 569 break; 570 } 571 if (changeok) { 572 set_his_want_state_will(option); 573 send_do(option, 0); 574 } else { 575 do_dont_resp[option]++; 576 send_dont(option, 0); 577 } 578 } else { 579 /* 580 * Option processing that should happen when 581 * we receive conformation of a change in 582 * state that we had requested. 583 */ 584 switch (option) { 585 case TELOPT_ECHO: 586 not42 = 0; /* looks like a 4.2 system */ 587 /* 588 * Egads, he responded "WILL ECHO". Turn 589 * it off right now! 590 */ 591 send_dont(option, 1); 592 /* 593 * "WILL ECHO". Kludge upon kludge! 594 * A 4.2 client is now echoing user input at 595 * the tty. This is probably undesireable and 596 * it should be stopped. The client will 597 * respond WONT TM to the DO TM that we send to 598 * check for kludge linemode. When the WONT TM 599 * arrives, linemode will be turned off and a 600 * change propogated to the pty. This change 601 * will cause us to process the new pty state 602 * in localstat(), which will notice that 603 * linemode is off and send a WILL ECHO 604 * so that we are properly in character mode and 605 * all is well. 606 */ 607 break; 608#ifdef LINEMODE 609 case TELOPT_LINEMODE: 610# ifdef KLUDGELINEMODE 611 /* 612 * Note client's desire to use linemode. 613 */ 614 lmodetype = REAL_LINEMODE; 615# endif /* KLUDGELINEMODE */ 616 func = doclientstat; 617 break; 618#endif /* LINEMODE */ 619 620#ifdef AUTHENTICATION 621 case TELOPT_AUTHENTICATION: 622 func = auth_request; 623 break; 624#endif 625 626#ifdef ENCRYPTION 627 case TELOPT_ENCRYPT: 628 func = encrypt_send_support; 629 break; 630#endif /* ENCRYPTION */ 631 case TELOPT_LFLOW: 632 func = flowstat; 633 break; 634 } 635 } 636 } 637 set_his_state_will(option); 638 if (func) 639 (*func)(); 640} /* end of willoption */ 641 642void 643send_dont(int option, int init) 644{ 645 if (init) { 646 if ((do_dont_resp[option] == 0 && his_state_is_wont(option)) || 647 his_want_state_is_wont(option)) 648 return; 649 set_his_want_state_wont(option); 650 do_dont_resp[option]++; 651 } 652 output_data((const char *)dont, option); 653 654 DIAG(TD_OPTIONS, printoption("td: send dont", option)); 655} 656 657void 658wontoption(int option) 659{ 660 /* 661 * Process client input. 662 */ 663 664 DIAG(TD_OPTIONS, printoption("td: recv wont", option)); 665 666 if (do_dont_resp[option]) { 667 do_dont_resp[option]--; 668 if (do_dont_resp[option] && his_state_is_wont(option)) 669 do_dont_resp[option]--; 670 } 671 if (do_dont_resp[option] == 0) { 672 if (his_want_state_is_will(option)) { 673 /* it is always ok to change to negative state */ 674 switch (option) { 675 case TELOPT_ECHO: 676 not42 = 1; /* doesn't seem to be a 4.2 system */ 677 break; 678 679 case TELOPT_BINARY: 680 init_termbuf(); 681 tty_binaryin(0); 682 set_termbuf(); 683 break; 684 685#ifdef LINEMODE 686 case TELOPT_LINEMODE: 687# ifdef KLUDGELINEMODE 688 /* 689 * If real linemode is supported, then client is 690 * asking to turn linemode off. 691 */ 692 if (lmodetype != REAL_LINEMODE) 693 break; 694 lmodetype = KLUDGE_LINEMODE; 695# endif /* KLUDGELINEMODE */ 696 clientstat(TELOPT_LINEMODE, WONT, 0); 697 break; 698#endif /* LINEMODE */ 699 700 case TELOPT_TM: 701 /* 702 * If we get a WONT TM, and had sent a DO TM, 703 * don't respond with a DONT TM, just leave it 704 * as is. Short circut the state machine to 705 * achive this. 706 */ 707 set_his_want_state_wont(TELOPT_TM); 708 return; 709 710 case TELOPT_LFLOW: 711 /* 712 * If we are not going to support flow control 713 * option, then let peer know that we can't 714 * change the flow control characters. 715 */ 716 slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS; 717 slctab[SLC_XON].defset.flag |= SLC_CANTCHANGE; 718 slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS; 719 slctab[SLC_XOFF].defset.flag |= SLC_CANTCHANGE; 720 break; 721 722#ifdef AUTHENTICATION 723 case TELOPT_AUTHENTICATION: 724 auth_finished(0, AUTH_REJECT); 725 break; 726#endif 727 728 /* 729 * For options that we might spin waiting for 730 * sub-negotiation, if the client turns off the 731 * option rather than responding to the request, 732 * we have to treat it here as if we got a response 733 * to the sub-negotiation, (by updating the timers) 734 * so that we'll break out of the loop. 735 */ 736 case TELOPT_TTYPE: 737 settimer(ttypesubopt); 738 break; 739 740 case TELOPT_TSPEED: 741 settimer(tspeedsubopt); 742 break; 743 744 case TELOPT_XDISPLOC: 745 settimer(xdisplocsubopt); 746 break; 747 748 case TELOPT_OLD_ENVIRON: 749 settimer(oenvironsubopt); 750 break; 751 752 case TELOPT_NEW_ENVIRON: 753 settimer(environsubopt); 754 break; 755 756 default: 757 break; 758 } 759 set_his_want_state_wont(option); 760 if (his_state_is_will(option)) 761 send_dont(option, 0); 762 } else { 763 switch (option) { 764 case TELOPT_TM: 765#if defined(LINEMODE) && defined(KLUDGELINEMODE) 766 if (lmodetype < NO_AUTOKLUDGE) { 767 lmodetype = NO_LINEMODE; 768 clientstat(TELOPT_LINEMODE, WONT, 0); 769 send_will(TELOPT_SGA, 1); 770 send_will(TELOPT_ECHO, 1); 771 } 772#endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */ 773 break; 774 775#ifdef AUTHENTICATION 776 case TELOPT_AUTHENTICATION: 777 auth_finished(0, AUTH_REJECT); 778 break; 779#endif 780 default: 781 break; 782 } 783 } 784 } 785 set_his_state_wont(option); 786 787} /* end of wontoption */ 788 789void 790send_will(int option, int init) 791{ 792 if (init) { 793 if ((will_wont_resp[option] == 0 && my_state_is_will(option))|| 794 my_want_state_is_will(option)) 795 return; 796 set_my_want_state_will(option); 797 will_wont_resp[option]++; 798 } 799 output_data((const char *)will, option); 800 801 DIAG(TD_OPTIONS, printoption("td: send will", option)); 802} 803 804#if !defined(LINEMODE) || !defined(KLUDGELINEMODE) 805/* 806 * When we get a DONT SGA, we will try once to turn it 807 * back on. If the other side responds DONT SGA, we 808 * leave it at that. This is so that when we talk to 809 * clients that understand KLUDGELINEMODE but not LINEMODE, 810 * we'll keep them in char-at-a-time mode. 811 */ 812int turn_on_sga = 0; 813#endif 814 815void 816dooption(int option) 817{ 818 int changeok = 0; 819 820 /* 821 * Process client input. 822 */ 823 824 DIAG(TD_OPTIONS, printoption("td: recv do", option)); 825 826 if (will_wont_resp[option]) { 827 will_wont_resp[option]--; 828 if (will_wont_resp[option] && my_state_is_will(option)) 829 will_wont_resp[option]--; 830 } 831 if ((will_wont_resp[option] == 0) && (my_want_state_is_wont(option))) { 832 switch (option) { 833 case TELOPT_ECHO: 834#ifdef LINEMODE 835# ifdef KLUDGELINEMODE 836 if (lmodetype == NO_LINEMODE) 837# else 838 if (his_state_is_wont(TELOPT_LINEMODE)) 839# endif 840#endif 841 { 842 init_termbuf(); 843 tty_setecho(1); 844 set_termbuf(); 845 } 846 changeok++; 847 break; 848 849 case TELOPT_BINARY: 850 init_termbuf(); 851 tty_binaryout(1); 852 set_termbuf(); 853 changeok++; 854 break; 855 856 case TELOPT_SGA: 857#if defined(LINEMODE) && defined(KLUDGELINEMODE) 858 /* 859 * If kludge linemode is in use, then we must 860 * process an incoming do SGA for linemode 861 * purposes. 862 */ 863 if (lmodetype == KLUDGE_LINEMODE) { 864 /* 865 * Receipt of "do SGA" in kludge 866 * linemode is the peer asking us to 867 * turn off linemode. Make note of 868 * the request. 869 */ 870 clientstat(TELOPT_LINEMODE, WONT, 0); 871 /* 872 * If linemode did not get turned off 873 * then don't tell peer that we did. 874 * Breaking here forces a wont SGA to 875 * be returned. 876 */ 877 if (linemode) 878 break; 879 } 880#else 881 turn_on_sga = 0; 882#endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */ 883 changeok++; 884 break; 885 886 case TELOPT_STATUS: 887 changeok++; 888 break; 889 890 case TELOPT_TM: 891 /* 892 * Special case for TM. We send a WILL, but 893 * pretend we sent a WONT. 894 */ 895 send_will(option, 0); 896 set_my_want_state_wont(option); 897 set_my_state_wont(option); 898 return; 899 900 case TELOPT_LOGOUT: 901 /* 902 * When we get a LOGOUT option, respond 903 * with a WILL LOGOUT, make sure that 904 * it gets written out to the network, 905 * and then just go away... 906 */ 907 set_my_want_state_will(TELOPT_LOGOUT); 908 send_will(TELOPT_LOGOUT, 0); 909 set_my_state_will(TELOPT_LOGOUT); 910 (void)netflush(); 911 cleanup(0); 912 /* NOT REACHED */ 913 break; 914 915#ifdef ENCRYPTION 916 case TELOPT_ENCRYPT: 917 changeok++; 918 break; 919#endif /* ENCRYPTION */ 920 case TELOPT_LINEMODE: 921 case TELOPT_TTYPE: 922 case TELOPT_NAWS: 923 case TELOPT_TSPEED: 924 case TELOPT_LFLOW: 925 case TELOPT_XDISPLOC: 926#ifdef TELOPT_ENVIRON 927 case TELOPT_NEW_ENVIRON: 928#endif 929 case TELOPT_OLD_ENVIRON: 930 default: 931 break; 932 } 933 if (changeok) { 934 set_my_want_state_will(option); 935 send_will(option, 0); 936 } else { 937 will_wont_resp[option]++; 938 send_wont(option, 0); 939 } 940 } 941 set_my_state_will(option); 942 943} /* end of dooption */ 944 945void 946send_wont(int option, int init) 947{ 948 if (init) { 949 if ((will_wont_resp[option] == 0 && my_state_is_wont(option)) || 950 my_want_state_is_wont(option)) 951 return; 952 set_my_want_state_wont(option); 953 will_wont_resp[option]++; 954 } 955 output_data((const char *)wont, option); 956 957 DIAG(TD_OPTIONS, printoption("td: send wont", option)); 958} 959 960void 961dontoption(int option) 962{ 963 /* 964 * Process client input. 965 */ 966 967 968 DIAG(TD_OPTIONS, printoption("td: recv dont", option)); 969 970 if (will_wont_resp[option]) { 971 will_wont_resp[option]--; 972 if (will_wont_resp[option] && my_state_is_wont(option)) 973 will_wont_resp[option]--; 974 } 975 if ((will_wont_resp[option] == 0) && (my_want_state_is_will(option))) { 976 switch (option) { 977 case TELOPT_BINARY: 978 init_termbuf(); 979 tty_binaryout(0); 980 set_termbuf(); 981 break; 982 983 case TELOPT_ECHO: /* we should stop echoing */ 984#ifdef LINEMODE 985# ifdef KLUDGELINEMODE 986 if ((lmodetype != REAL_LINEMODE) && 987 (lmodetype != KLUDGE_LINEMODE)) 988# else 989 if (his_state_is_wont(TELOPT_LINEMODE)) 990# endif 991#endif 992 { 993 init_termbuf(); 994 tty_setecho(0); 995 set_termbuf(); 996 } 997 break; 998 999 case TELOPT_SGA: 1000#if defined(LINEMODE) && defined(KLUDGELINEMODE) 1001 /* 1002 * If kludge linemode is in use, then we 1003 * must process an incoming do SGA for 1004 * linemode purposes. 1005 */ 1006 if ((lmodetype == KLUDGE_LINEMODE) || 1007 (lmodetype == KLUDGE_OK)) { 1008 /* 1009 * The client is asking us to turn 1010 * linemode on. 1011 */ 1012 lmodetype = KLUDGE_LINEMODE; 1013 clientstat(TELOPT_LINEMODE, WILL, 0); 1014 /* 1015 * If we did not turn line mode on, 1016 * then what do we say? Will SGA? 1017 * This violates design of telnet. 1018 * Gross. Very Gross. 1019 */ 1020 } 1021 break; 1022#else 1023 set_my_want_state_wont(option); 1024 if (my_state_is_will(option)) 1025 send_wont(option, 0); 1026 set_my_state_wont(option); 1027 if (turn_on_sga ^= 1) 1028 send_will(option, 1); 1029 return; 1030#endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */ 1031 1032 default: 1033 break; 1034 } 1035 1036 set_my_want_state_wont(option); 1037 if (my_state_is_will(option)) 1038 send_wont(option, 0); 1039 } 1040 set_my_state_wont(option); 1041 1042} /* end of dontoption */ 1043 1044#ifdef ENV_HACK 1045int env_ovar = -1; 1046int env_ovalue = -1; 1047#else /* ENV_HACK */ 1048# define env_ovar OLD_ENV_VAR 1049# define env_ovalue OLD_ENV_VALUE 1050#endif /* ENV_HACK */ 1051 1052/* 1053 * suboption() 1054 * 1055 * Look at the sub-option buffer, and try to be helpful to the other 1056 * side. 1057 * 1058 * Currently we recognize: 1059 * 1060 * Terminal type is 1061 * Linemode 1062 * Window size 1063 * Terminal speed 1064 */ 1065void 1066suboption(void) 1067{ 1068 int subchar; 1069 1070 DIAG(TD_OPTIONS, {netflush(); printsub('<', subpointer, SB_LEN()+2);}); 1071 1072 subchar = SB_GET(); 1073 switch (subchar) { 1074 case TELOPT_TSPEED: { 1075 int xspeed, rspeed; 1076 1077 if (his_state_is_wont(TELOPT_TSPEED)) /* Ignore if option disabled */ 1078 break; 1079 1080 settimer(tspeedsubopt); 1081 1082 if (SB_EOF() || SB_GET() != TELQUAL_IS) 1083 return; 1084 1085 xspeed = atoi((char *)subpointer); 1086 1087 while (SB_GET() != ',' && !SB_EOF()); 1088 if (SB_EOF()) 1089 return; 1090 1091 rspeed = atoi((char *)subpointer); 1092 clientstat(TELOPT_TSPEED, xspeed, rspeed); 1093 1094 break; 1095 1096 } /* end of case TELOPT_TSPEED */ 1097 1098 case TELOPT_TTYPE: { /* Yaaaay! */ 1099 static char terminalname[41]; 1100 1101 if (his_state_is_wont(TELOPT_TTYPE)) /* Ignore if option disabled */ 1102 break; 1103 settimer(ttypesubopt); 1104 1105 if (SB_EOF() || SB_GET() != TELQUAL_IS) { 1106 return; /* ??? XXX but, this is the most robust */ 1107 } 1108 1109 terminaltype = terminalname; 1110 1111 while ((terminaltype < (terminalname + sizeof terminalname-1)) && 1112 !SB_EOF()) { 1113 int c; 1114 1115 c = SB_GET(); 1116 if (isupper(c)) { 1117 c = tolower(c); 1118 } 1119 *terminaltype++ = c; /* accumulate name */ 1120 } 1121 *terminaltype = 0; 1122 terminaltype = terminalname; 1123 break; 1124 } /* end of case TELOPT_TTYPE */ 1125 1126 case TELOPT_NAWS: { 1127 int xwinsize, ywinsize; 1128 1129 if (his_state_is_wont(TELOPT_NAWS)) /* Ignore if option disabled */ 1130 break; 1131 1132 if (SB_EOF()) 1133 return; 1134 xwinsize = SB_GET() << 8; 1135 if (SB_EOF()) 1136 return; 1137 xwinsize |= SB_GET(); 1138 if (SB_EOF()) 1139 return; 1140 ywinsize = SB_GET() << 8; 1141 if (SB_EOF()) 1142 return; 1143 ywinsize |= SB_GET(); 1144 clientstat(TELOPT_NAWS, xwinsize, ywinsize); 1145 1146 break; 1147 1148 } /* end of case TELOPT_NAWS */ 1149 1150#ifdef LINEMODE 1151 case TELOPT_LINEMODE: { 1152 int request; 1153 1154 if (his_state_is_wont(TELOPT_LINEMODE)) /* Ignore if option disabled */ 1155 break; 1156 /* 1157 * Process linemode suboptions. 1158 */ 1159 if (SB_EOF()) 1160 break; /* garbage was sent */ 1161 request = SB_GET(); /* get will/wont */ 1162 1163 if (SB_EOF()) 1164 break; /* another garbage check */ 1165 1166 if (request == LM_SLC) { /* SLC is not preceeded by WILL or WONT */ 1167 /* 1168 * Process suboption buffer of slc's 1169 */ 1170 start_slc(1); 1171 do_opt_slc(subpointer, subend - subpointer); 1172 (void) end_slc(0); 1173 break; 1174 } else if (request == LM_MODE) { 1175 if (SB_EOF()) 1176 return; 1177 useeditmode = SB_GET(); /* get mode flag */ 1178 clientstat(LM_MODE, 0, 0); 1179 break; 1180 } 1181 1182 if (SB_EOF()) 1183 break; 1184 switch (SB_GET()) { /* what suboption? */ 1185 case LM_FORWARDMASK: 1186 /* 1187 * According to spec, only server can send request for 1188 * forwardmask, and client can only return a positive response. 1189 * So don't worry about it. 1190 */ 1191 1192 default: 1193 break; 1194 } 1195 break; 1196 } /* end of case TELOPT_LINEMODE */ 1197#endif 1198 case TELOPT_STATUS: { 1199 int mode; 1200 1201 if (SB_EOF()) 1202 break; 1203 mode = SB_GET(); 1204 switch (mode) { 1205 case TELQUAL_SEND: 1206 if (my_state_is_will(TELOPT_STATUS)) 1207 send_status(); 1208 break; 1209 1210 case TELQUAL_IS: 1211 break; 1212 1213 default: 1214 break; 1215 } 1216 break; 1217 } /* end of case TELOPT_STATUS */ 1218 1219 case TELOPT_XDISPLOC: { 1220 if (SB_EOF() || SB_GET() != TELQUAL_IS) 1221 return; 1222 settimer(xdisplocsubopt); 1223 subpointer[SB_LEN()] = '\0'; 1224 (void)setenv("DISPLAY", (char *)subpointer, 1); 1225 break; 1226 } /* end of case TELOPT_XDISPLOC */ 1227 1228#ifdef TELOPT_NEW_ENVIRON 1229 case TELOPT_NEW_ENVIRON: 1230#endif 1231 case TELOPT_OLD_ENVIRON: { 1232 int c; 1233 char *cp, *varp, *valp; 1234 1235 if (SB_EOF()) 1236 return; 1237 c = SB_GET(); 1238 if (c == TELQUAL_IS) { 1239 if (subchar == TELOPT_OLD_ENVIRON) 1240 settimer(oenvironsubopt); 1241 else 1242 settimer(environsubopt); 1243 } else if (c != TELQUAL_INFO) { 1244 return; 1245 } 1246 1247#ifdef TELOPT_NEW_ENVIRON 1248 if (subchar == TELOPT_NEW_ENVIRON) { 1249 while (!SB_EOF()) { 1250 c = SB_GET(); 1251 if ((c == NEW_ENV_VAR) || (c == ENV_USERVAR)) 1252 break; 1253 } 1254 } else 1255#endif 1256 { 1257#ifdef ENV_HACK 1258 /* 1259 * We only want to do this if we haven't already decided 1260 * whether or not the other side has its VALUE and VAR 1261 * reversed. 1262 */ 1263 if (env_ovar < 0) { 1264 int last = -1; /* invalid value */ 1265 int empty = 0; 1266 int got_var = 0, got_value = 0, got_uservar = 0; 1267 1268 /* 1269 * The other side might have its VALUE and VAR values 1270 * reversed. To be interoperable, we need to determine 1271 * which way it is. If the first recognized character 1272 * is a VAR or VALUE, then that will tell us what 1273 * type of client it is. If the fist recognized 1274 * character is a USERVAR, then we continue scanning 1275 * the suboption looking for two consecutive 1276 * VAR or VALUE fields. We should not get two 1277 * consecutive VALUE fields, so finding two 1278 * consecutive VALUE or VAR fields will tell us 1279 * what the client is. 1280 */ 1281 SB_SAVE(); 1282 while (!SB_EOF()) { 1283 c = SB_GET(); 1284 switch(c) { 1285 case OLD_ENV_VAR: 1286 if (last < 0 || last == OLD_ENV_VAR 1287 || (empty && (last == OLD_ENV_VALUE))) 1288 goto env_ovar_ok; 1289 got_var++; 1290 last = OLD_ENV_VAR; 1291 break; 1292 case OLD_ENV_VALUE: 1293 if (last < 0 || last == OLD_ENV_VALUE 1294 || (empty && (last == OLD_ENV_VAR))) 1295 goto env_ovar_wrong; 1296 got_value++; 1297 last = OLD_ENV_VALUE; 1298 break; 1299 case ENV_USERVAR: 1300 /* count strings of USERVAR as one */ 1301 if (last != ENV_USERVAR) 1302 got_uservar++; 1303 if (empty) { 1304 if (last == OLD_ENV_VALUE) 1305 goto env_ovar_ok; 1306 if (last == OLD_ENV_VAR) 1307 goto env_ovar_wrong; 1308 } 1309 last = ENV_USERVAR; 1310 break; 1311 case ENV_ESC: 1312 if (!SB_EOF()) 1313 c = SB_GET(); 1314 /* FALLTHROUGH */ 1315 default: 1316 empty = 0; 1317 continue; 1318 } 1319 empty = 1; 1320 } 1321 if (empty) { 1322 if (last == OLD_ENV_VALUE) 1323 goto env_ovar_ok; 1324 if (last == OLD_ENV_VAR) 1325 goto env_ovar_wrong; 1326 } 1327 /* 1328 * Ok, the first thing was a USERVAR, and there 1329 * are not two consecutive VAR or VALUE commands, 1330 * and none of the VAR or VALUE commands are empty. 1331 * If the client has sent us a well-formed option, 1332 * then the number of VALUEs received should always 1333 * be less than or equal to the number of VARs and 1334 * USERVARs received. 1335 * 1336 * If we got exactly as many VALUEs as VARs and 1337 * USERVARs, the client has the same definitions. 1338 * 1339 * If we got exactly as many VARs as VALUEs and 1340 * USERVARS, the client has reversed definitions. 1341 */ 1342 if (got_uservar + got_var == got_value) { 1343 env_ovar_ok: 1344 env_ovar = OLD_ENV_VAR; 1345 env_ovalue = OLD_ENV_VALUE; 1346 } else if (got_uservar + got_value == got_var) { 1347 env_ovar_wrong: 1348 env_ovar = OLD_ENV_VALUE; 1349 env_ovalue = OLD_ENV_VAR; 1350 DIAG(TD_OPTIONS, 1351 output_data("ENVIRON VALUE and VAR are reversed!\r\n")); 1352 1353 } 1354 } 1355 SB_RESTORE(); 1356#endif 1357 1358 while (!SB_EOF()) { 1359 c = SB_GET(); 1360 if ((c == env_ovar) || (c == ENV_USERVAR)) 1361 break; 1362 } 1363 } 1364 1365 if (SB_EOF()) 1366 return; 1367 1368 cp = varp = (char *)subpointer; 1369 valp = 0; 1370 1371 while (!SB_EOF()) { 1372 c = SB_GET(); 1373 if (subchar == TELOPT_OLD_ENVIRON) { 1374 if (c == env_ovar) 1375 c = NEW_ENV_VAR; 1376 else if (c == env_ovalue) 1377 c = NEW_ENV_VALUE; 1378 } 1379 switch (c) { 1380 1381 case NEW_ENV_VALUE: 1382 *cp = '\0'; 1383 cp = valp = (char *)subpointer; 1384 break; 1385 1386 case NEW_ENV_VAR: 1387 case ENV_USERVAR: 1388 *cp = '\0'; 1389 if (valp) 1390 (void)setenv(varp, valp, 1); 1391 else 1392 unsetenv(varp); 1393 cp = varp = (char *)subpointer; 1394 valp = 0; 1395 break; 1396 1397 case ENV_ESC: 1398 if (SB_EOF()) 1399 break; 1400 c = SB_GET(); 1401 /* FALLTHROUGH */ 1402 default: 1403 *cp++ = c; 1404 break; 1405 } 1406 } 1407 *cp = '\0'; 1408 if (valp) 1409 (void)setenv(varp, valp, 1); 1410 else 1411 unsetenv(varp); 1412 break; 1413 } /* end of case TELOPT_NEW_ENVIRON */ 1414#ifdef AUTHENTICATION 1415 case TELOPT_AUTHENTICATION: 1416 if (SB_EOF()) 1417 break; 1418 switch(SB_GET()) { 1419 case TELQUAL_SEND: 1420 case TELQUAL_REPLY: 1421 /* 1422 * These are sent by us and cannot be sent by 1423 * the client. 1424 */ 1425 break; 1426 case TELQUAL_IS: 1427 auth_is(subpointer, SB_LEN()); 1428 break; 1429 case TELQUAL_NAME: 1430 auth_name(subpointer, SB_LEN()); 1431 break; 1432 } 1433 break; 1434#endif 1435#ifdef ENCRYPTION 1436 case TELOPT_ENCRYPT: 1437 if (SB_EOF()) 1438 break; 1439 switch(SB_GET()) { 1440 case ENCRYPT_SUPPORT: 1441 encrypt_support(subpointer, SB_LEN()); 1442 break; 1443 case ENCRYPT_IS: 1444 encrypt_is(subpointer, SB_LEN()); 1445 break; 1446 case ENCRYPT_REPLY: 1447 encrypt_reply(subpointer, SB_LEN()); 1448 break; 1449 case ENCRYPT_START: 1450 encrypt_start(subpointer, SB_LEN()); 1451 break; 1452 case ENCRYPT_END: 1453 encrypt_end(); 1454 break; 1455 case ENCRYPT_REQSTART: 1456 encrypt_request_start(subpointer, SB_LEN()); 1457 break; 1458 case ENCRYPT_REQEND: 1459 /* 1460 * We can always send an REQEND so that we cannot 1461 * get stuck encrypting. We should only get this 1462 * if we have been able to get in the correct mode 1463 * anyhow. 1464 */ 1465 encrypt_request_end(); 1466 break; 1467 case ENCRYPT_ENC_KEYID: 1468 encrypt_enc_keyid(subpointer, SB_LEN()); 1469 break; 1470 case ENCRYPT_DEC_KEYID: 1471 encrypt_dec_keyid(subpointer, SB_LEN()); 1472 break; 1473 default: 1474 break; 1475 } 1476 break; 1477#endif /* ENCRYPTION */ 1478 1479 default: 1480 break; 1481 } /* end of switch */ 1482 1483} /* end of suboption */ 1484 1485static void 1486doclientstat(void) 1487{ 1488 clientstat(TELOPT_LINEMODE, WILL, 0); 1489} 1490 1491#define ADD(c) *ncp++ = c 1492#define ADD_DATA(c) { *ncp++ = c; if (c == SE || c == IAC) *ncp++ = c; } 1493void 1494send_status(void) 1495{ 1496 unsigned char statusbuf[256]; 1497 unsigned char *ncp; 1498 unsigned char i; 1499 1500 ncp = statusbuf; 1501 1502 netflush(); /* get rid of anything waiting to go out */ 1503 1504 ADD(IAC); 1505 ADD(SB); 1506 ADD(TELOPT_STATUS); 1507 ADD(TELQUAL_IS); 1508 1509 /* 1510 * We check the want_state rather than the current state, 1511 * because if we received a DO/WILL for an option that we 1512 * don't support, and the other side didn't send a DONT/WONT 1513 * in response to our WONT/DONT, then the "state" will be 1514 * WILL/DO, and the "want_state" will be WONT/DONT. We 1515 * need to go by the latter. 1516 */ 1517 for (i = 0; i < (unsigned char)NTELOPTS; i++) { 1518 if (my_want_state_is_will(i)) { 1519 ADD(WILL); 1520 ADD_DATA(i); 1521 if (i == IAC) 1522 ADD(IAC); 1523 } 1524 if (his_want_state_is_will(i)) { 1525 ADD(DO); 1526 ADD_DATA(i); 1527 if (i == IAC) 1528 ADD(IAC); 1529 } 1530 } 1531 1532 if (his_want_state_is_will(TELOPT_LFLOW)) { 1533 ADD(SB); 1534 ADD(TELOPT_LFLOW); 1535 if (flowmode) { 1536 ADD(LFLOW_ON); 1537 } else { 1538 ADD(LFLOW_OFF); 1539 } 1540 ADD(SE); 1541 1542 if (restartany >= 0) { 1543 ADD(SB); 1544 ADD(TELOPT_LFLOW); 1545 if (restartany) { 1546 ADD(LFLOW_RESTART_ANY); 1547 } else { 1548 ADD(LFLOW_RESTART_XON); 1549 } 1550 ADD(SE); 1551 } 1552 } 1553 1554#ifdef LINEMODE 1555 if (his_want_state_is_will(TELOPT_LINEMODE)) { 1556 unsigned char *cp, *cpe; 1557 int len; 1558 1559 ADD(SB); 1560 ADD(TELOPT_LINEMODE); 1561 ADD(LM_MODE); 1562 ADD_DATA(editmode); 1563 ADD(SE); 1564 1565 ADD(SB); 1566 ADD(TELOPT_LINEMODE); 1567 ADD(LM_SLC); 1568 start_slc(0); 1569 send_slc(); 1570 len = end_slc(&cp); 1571 for (cpe = cp + len; cp < cpe; cp++) 1572 ADD_DATA(*cp); 1573 ADD(SE); 1574 } 1575#endif /* LINEMODE */ 1576 1577 ADD(IAC); 1578 ADD(SE); 1579 1580 output_datalen(statusbuf, ncp - statusbuf); 1581 netflush(); /* Send it on its way */ 1582 1583 DIAG(TD_OPTIONS, 1584 {printsub('>', statusbuf, ncp - statusbuf); netflush();}); 1585} 1586 1587/* 1588 * This function appends data to nfrontp and advances nfrontp. 1589 * Returns the number of characters written altogether (the 1590 * buffer may have been flushed in the process). 1591 */ 1592 1593int 1594output_data(const char *format, ...) 1595{ 1596 va_list args; 1597 int len; 1598 char *buf; 1599 1600 va_start(args, format); 1601 if ((len = vasprintf(&buf, format, args)) == -1) { 1602 va_end(args); 1603 return -1; 1604 } 1605 output_datalen(buf, len); 1606 va_end(args); 1607 free(buf); 1608 return (len); 1609} 1610 1611void 1612output_datalen(const char *buf, int len) 1613{ 1614 int remaining, copied; 1615 1616 remaining = BUFSIZ - (nfrontp - netobuf); 1617 while (len > 0) { 1618 /* Free up enough space if the room is too low*/ 1619 if ((len > BUFSIZ ? BUFSIZ : len) > remaining) { 1620 netflush(); 1621 remaining = BUFSIZ - (nfrontp - netobuf); 1622 } 1623 1624 /* Copy out as much as will fit */ 1625 copied = remaining > len ? len : remaining; 1626 memmove(nfrontp, buf, copied); 1627 nfrontp += copied; 1628 len -= copied; 1629 remaining -= copied; 1630 buf += copied; 1631 } 1632 return; 1633} 1634