1 /*
2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #if 0
31 #ifndef lint
32 static const char sccsid[] = "@(#)state.c 8.5 (Berkeley) 5/30/95";
33 #endif
34 #endif
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37
38 #include <stdarg.h>
39 #include "telnetd.h"
40 #ifdef AUTHENTICATION
41 #include <libtelnet/auth.h>
42 #endif
43 #ifdef ENCRYPTION
44 #include <libtelnet/encrypt.h>
45 #endif
46
47 unsigned char doopt[] = { IAC, DO, '%', 'c', 0 };
48 unsigned char dont[] = { IAC, DONT, '%', 'c', 0 };
49 unsigned char will[] = { IAC, WILL, '%', 'c', 0 };
50 unsigned char wont[] = { IAC, WONT, '%', 'c', 0 };
51 int not42 = 1;
52
53 /*
54 * Buffer for sub-options, and macros
55 * for suboptions buffer manipulations
56 */
57 unsigned char subbuffer[512], *subpointer= subbuffer, *subend= subbuffer;
58
59 #define SB_CLEAR() subpointer = subbuffer
60 #define SB_TERM() { subend = subpointer; SB_CLEAR(); }
61 #define SB_ACCUM(c) if (subpointer < (subbuffer+sizeof subbuffer)) { \
62 *subpointer++ = (c); \
63 }
64 #define SB_GET() ((*subpointer++)&0xff)
65 #define SB_EOF() (subpointer >= subend)
66 #define SB_LEN() (subend - subpointer)
67
68 #ifdef ENV_HACK
69 unsigned char *subsave;
70 #define SB_SAVE() subsave = subpointer;
71 #define SB_RESTORE() subpointer = subsave;
72 #endif
73
74
75 /*
76 * State for recv fsm
77 */
78 #define TS_DATA 0 /* base state */
79 #define TS_IAC 1 /* look for double IAC's */
80 #define TS_CR 2 /* CR-LF ->'s CR */
81 #define TS_SB 3 /* throw away begin's... */
82 #define TS_SE 4 /* ...end's (suboption negotiation) */
83 #define TS_WILL 5 /* will option negotiation */
84 #define TS_WONT 6 /* wont " */
85 #define TS_DO 7 /* do " */
86 #define TS_DONT 8 /* dont " */
87
88 static void doclientstat(void);
89
90 void
telrcv(void)91 telrcv(void)
92 {
93 int c;
94 static int state = TS_DATA;
95
96 while (ncc > 0) {
97 if ((&ptyobuf[BUFSIZ] - pfrontp) < 2)
98 break;
99 c = *netip++ & 0377, ncc--;
100 #ifdef ENCRYPTION
101 if (decrypt_input)
102 c = (*decrypt_input)(c);
103 #endif /* ENCRYPTION */
104 switch (state) {
105
106 case TS_CR:
107 state = TS_DATA;
108 /* Strip off \n or \0 after a \r */
109 if ((c == 0) || (c == '\n')) {
110 break;
111 }
112 /* FALLTHROUGH */
113
114 case TS_DATA:
115 if (c == IAC) {
116 state = TS_IAC;
117 break;
118 }
119 /*
120 * We now map \r\n ==> \r for pragmatic reasons.
121 * Many client implementations send \r\n when
122 * the user hits the CarriageReturn key.
123 *
124 * We USED to map \r\n ==> \n, since \r\n says
125 * that we want to be in column 1 of the next
126 * printable line, and \n is the standard
127 * unix way of saying that (\r is only good
128 * if CRMOD is set, which it normally is).
129 */
130 if ((c == '\r') && his_state_is_wont(TELOPT_BINARY)) {
131 int nc = *netip;
132 #ifdef ENCRYPTION
133 if (decrypt_input)
134 nc = (*decrypt_input)(nc & 0xff);
135 #endif /* ENCRYPTION */
136 #ifdef LINEMODE
137 /*
138 * If we are operating in linemode,
139 * convert to local end-of-line.
140 */
141 if (linemode && (ncc > 0) && (('\n' == nc) ||
142 ((0 == nc) && tty_iscrnl())) ) {
143 netip++; ncc--;
144 c = '\n';
145 } else
146 #endif
147 {
148 #ifdef ENCRYPTION
149 if (decrypt_input)
150 (void)(*decrypt_input)(-1);
151 #endif /* ENCRYPTION */
152 state = TS_CR;
153 }
154 }
155 *pfrontp++ = c;
156 break;
157
158 case TS_IAC:
159 gotiac: switch (c) {
160
161 /*
162 * Send the process on the pty side an
163 * interrupt. Do this with a NULL or
164 * interrupt char; depending on the tty mode.
165 */
166 case IP:
167 DIAG(TD_OPTIONS,
168 printoption("td: recv IAC", c));
169 interrupt();
170 break;
171
172 case BREAK:
173 DIAG(TD_OPTIONS,
174 printoption("td: recv IAC", c));
175 sendbrk();
176 break;
177
178 /*
179 * Are You There?
180 */
181 case AYT:
182 DIAG(TD_OPTIONS,
183 printoption("td: recv IAC", c));
184 recv_ayt();
185 break;
186
187 /*
188 * Abort Output
189 */
190 case AO:
191 {
192 DIAG(TD_OPTIONS,
193 printoption("td: recv IAC", c));
194 ptyflush(); /* half-hearted */
195 init_termbuf();
196
197 if (slctab[SLC_AO].sptr &&
198 *slctab[SLC_AO].sptr != (cc_t)(_POSIX_VDISABLE)) {
199 *pfrontp++ =
200 (unsigned char)*slctab[SLC_AO].sptr;
201 }
202
203 netclear(); /* clear buffer back */
204 output_data("%c%c", IAC, DM);
205 neturg = nfrontp-1; /* off by one XXX */
206 DIAG(TD_OPTIONS,
207 printoption("td: send IAC", DM));
208 break;
209 }
210
211 /*
212 * Erase Character and
213 * Erase Line
214 */
215 case EC:
216 case EL:
217 {
218 cc_t ch;
219
220 DIAG(TD_OPTIONS,
221 printoption("td: recv IAC", c));
222 ptyflush(); /* half-hearted */
223 init_termbuf();
224 if (c == EC)
225 ch = *slctab[SLC_EC].sptr;
226 else
227 ch = *slctab[SLC_EL].sptr;
228 if (ch != (cc_t)(_POSIX_VDISABLE))
229 *pfrontp++ = (unsigned char)ch;
230 break;
231 }
232
233 /*
234 * Check for urgent data...
235 */
236 case DM:
237 DIAG(TD_OPTIONS,
238 printoption("td: recv IAC", c));
239 SYNCHing = stilloob(net);
240 settimer(gotDM);
241 break;
242
243
244 /*
245 * Begin option subnegotiation...
246 */
247 case SB:
248 state = TS_SB;
249 SB_CLEAR();
250 continue;
251
252 case WILL:
253 state = TS_WILL;
254 continue;
255
256 case WONT:
257 state = TS_WONT;
258 continue;
259
260 case DO:
261 state = TS_DO;
262 continue;
263
264 case DONT:
265 state = TS_DONT;
266 continue;
267 case EOR:
268 if (his_state_is_will(TELOPT_EOR))
269 doeof();
270 break;
271
272 /*
273 * Handle RFC 10xx Telnet linemode option additions
274 * to command stream (EOF, SUSP, ABORT).
275 */
276 case xEOF:
277 doeof();
278 break;
279
280 case SUSP:
281 sendsusp();
282 break;
283
284 case ABORT:
285 sendbrk();
286 break;
287
288 case IAC:
289 *pfrontp++ = c;
290 break;
291 }
292 state = TS_DATA;
293 break;
294
295 case TS_SB:
296 if (c == IAC) {
297 state = TS_SE;
298 } else {
299 SB_ACCUM(c);
300 }
301 break;
302
303 case TS_SE:
304 if (c != SE) {
305 if (c != IAC) {
306 /*
307 * bad form of suboption negotiation.
308 * handle it in such a way as to avoid
309 * damage to local state. Parse
310 * suboption buffer found so far,
311 * then treat remaining stream as
312 * another command sequence.
313 */
314
315 /* for DIAGNOSTICS */
316 SB_ACCUM(IAC);
317 SB_ACCUM(c);
318 subpointer -= 2;
319
320 SB_TERM();
321 suboption();
322 state = TS_IAC;
323 goto gotiac;
324 }
325 SB_ACCUM(c);
326 state = TS_SB;
327 } else {
328 /* for DIAGNOSTICS */
329 SB_ACCUM(IAC);
330 SB_ACCUM(SE);
331 subpointer -= 2;
332
333 SB_TERM();
334 suboption(); /* handle sub-option */
335 state = TS_DATA;
336 }
337 break;
338
339 case TS_WILL:
340 willoption(c);
341 state = TS_DATA;
342 continue;
343
344 case TS_WONT:
345 wontoption(c);
346 state = TS_DATA;
347 continue;
348
349 case TS_DO:
350 dooption(c);
351 state = TS_DATA;
352 continue;
353
354 case TS_DONT:
355 dontoption(c);
356 state = TS_DATA;
357 continue;
358
359 default:
360 syslog(LOG_ERR, "panic state=%d", state);
361 printf("telnetd: panic state=%d\n", state);
362 exit(1);
363 }
364 }
365 } /* end of telrcv */
366
367 /*
368 * The will/wont/do/dont state machines are based on Dave Borman's
369 * Telnet option processing state machine.
370 *
371 * These correspond to the following states:
372 * my_state = the last negotiated state
373 * want_state = what I want the state to go to
374 * want_resp = how many requests I have sent
375 * All state defaults are negative, and resp defaults to 0.
376 *
377 * When initiating a request to change state to new_state:
378 *
379 * if ((want_resp == 0 && new_state == my_state) || want_state == new_state) {
380 * do nothing;
381 * } else {
382 * want_state = new_state;
383 * send new_state;
384 * want_resp++;
385 * }
386 *
387 * When receiving new_state:
388 *
389 * if (want_resp) {
390 * want_resp--;
391 * if (want_resp && (new_state == my_state))
392 * want_resp--;
393 * }
394 * if ((want_resp == 0) && (new_state != want_state)) {
395 * if (ok_to_switch_to new_state)
396 * want_state = new_state;
397 * else
398 * want_resp++;
399 * send want_state;
400 * }
401 * my_state = new_state;
402 *
403 * Note that new_state is implied in these functions by the function itself.
404 * will and do imply positive new_state, wont and dont imply negative.
405 *
406 * Finally, there is one catch. If we send a negative response to a
407 * positive request, my_state will be the positive while want_state will
408 * remain negative. my_state will revert to negative when the negative
409 * acknowlegment arrives from the peer. Thus, my_state generally tells
410 * us not only the last negotiated state, but also tells us what the peer
411 * wants to be doing as well. It is important to understand this difference
412 * as we may wish to be processing data streams based on our desired state
413 * (want_state) or based on what the peer thinks the state is (my_state).
414 *
415 * This all works fine because if the peer sends a positive request, the data
416 * that we receive prior to negative acknowlegment will probably be affected
417 * by the positive state, and we can process it as such (if we can; if we
418 * can't then it really doesn't matter). If it is that important, then the
419 * peer probably should be buffering until this option state negotiation
420 * is complete.
421 *
422 */
423 void
send_do(int option,int init)424 send_do(int option, int init)
425 {
426 if (init) {
427 if ((do_dont_resp[option] == 0 && his_state_is_will(option)) ||
428 his_want_state_is_will(option))
429 return;
430 /*
431 * Special case for TELOPT_TM: We send a DO, but pretend
432 * that we sent a DONT, so that we can send more DOs if
433 * we want to.
434 */
435 if (option == TELOPT_TM)
436 set_his_want_state_wont(option);
437 else
438 set_his_want_state_will(option);
439 do_dont_resp[option]++;
440 }
441 output_data((const char *)doopt, option);
442
443 DIAG(TD_OPTIONS, printoption("td: send do", option));
444 }
445
446 void
willoption(int option)447 willoption(int option)
448 {
449 int changeok = 0;
450 void (*func)(void) = 0;
451
452 /*
453 * process input from peer.
454 */
455
456 DIAG(TD_OPTIONS, printoption("td: recv will", option));
457
458 if (do_dont_resp[option]) {
459 do_dont_resp[option]--;
460 if (do_dont_resp[option] && his_state_is_will(option))
461 do_dont_resp[option]--;
462 }
463 if (do_dont_resp[option] == 0) {
464 if (his_want_state_is_wont(option)) {
465 switch (option) {
466
467 case TELOPT_BINARY:
468 init_termbuf();
469 tty_binaryin(1);
470 set_termbuf();
471 changeok++;
472 break;
473
474 case TELOPT_ECHO:
475 /*
476 * See comments below for more info.
477 */
478 not42 = 0; /* looks like a 4.2 system */
479 break;
480
481 case TELOPT_TM:
482 #if defined(LINEMODE) && defined(KLUDGELINEMODE)
483 /*
484 * This telnetd implementation does not really
485 * support timing marks, it just uses them to
486 * support the kludge linemode stuff. If we
487 * receive a will or wont TM in response to our
488 * do TM request that may have been sent to
489 * determine kludge linemode support, process
490 * it, otherwise TM should get a negative
491 * response back.
492 */
493 /*
494 * Handle the linemode kludge stuff.
495 * If we are not currently supporting any
496 * linemode at all, then we assume that this
497 * is the client telling us to use kludge
498 * linemode in response to our query. Set the
499 * linemode type that is to be supported, note
500 * that the client wishes to use linemode, and
501 * eat the will TM as though it never arrived.
502 */
503 if (lmodetype < KLUDGE_LINEMODE) {
504 lmodetype = KLUDGE_LINEMODE;
505 clientstat(TELOPT_LINEMODE, WILL, 0);
506 send_wont(TELOPT_SGA, 1);
507 } else if (lmodetype == NO_AUTOKLUDGE) {
508 lmodetype = KLUDGE_OK;
509 }
510 #endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
511 /*
512 * We never respond to a WILL TM, and
513 * we leave the state WONT.
514 */
515 return;
516
517 case TELOPT_LFLOW:
518 /*
519 * If we are going to support flow control
520 * option, then don't worry peer that we can't
521 * change the flow control characters.
522 */
523 slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
524 slctab[SLC_XON].defset.flag |= SLC_DEFAULT;
525 slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
526 slctab[SLC_XOFF].defset.flag |= SLC_DEFAULT;
527 case TELOPT_TTYPE:
528 case TELOPT_SGA:
529 case TELOPT_NAWS:
530 case TELOPT_TSPEED:
531 case TELOPT_XDISPLOC:
532 case TELOPT_NEW_ENVIRON:
533 case TELOPT_OLD_ENVIRON:
534 changeok++;
535 break;
536
537 #ifdef LINEMODE
538 case TELOPT_LINEMODE:
539 # ifdef KLUDGELINEMODE
540 /*
541 * Note client's desire to use linemode.
542 */
543 lmodetype = REAL_LINEMODE;
544 # endif /* KLUDGELINEMODE */
545 func = doclientstat;
546 changeok++;
547 break;
548 #endif /* LINEMODE */
549
550 #ifdef AUTHENTICATION
551 case TELOPT_AUTHENTICATION:
552 if (auth_level >= 0) {
553 func = auth_request;
554 changeok++;
555 }
556 break;
557 #endif
558
559 #ifdef ENCRYPTION
560 case TELOPT_ENCRYPT:
561 func = encrypt_send_support;
562 changeok++;
563 break;
564 #endif /* ENCRYPTION */
565
566 default:
567 break;
568 }
569 if (changeok) {
570 set_his_want_state_will(option);
571 send_do(option, 0);
572 } else {
573 do_dont_resp[option]++;
574 send_dont(option, 0);
575 }
576 } else {
577 /*
578 * Option processing that should happen when
579 * we receive conformation of a change in
580 * state that we had requested.
581 */
582 switch (option) {
583 case TELOPT_ECHO:
584 not42 = 0; /* looks like a 4.2 system */
585 /*
586 * Egads, he responded "WILL ECHO". Turn
587 * it off right now!
588 */
589 send_dont(option, 1);
590 /*
591 * "WILL ECHO". Kludge upon kludge!
592 * A 4.2 client is now echoing user input at
593 * the tty. This is probably undesireable and
594 * it should be stopped. The client will
595 * respond WONT TM to the DO TM that we send to
596 * check for kludge linemode. When the WONT TM
597 * arrives, linemode will be turned off and a
598 * change propogated to the pty. This change
599 * will cause us to process the new pty state
600 * in localstat(), which will notice that
601 * linemode is off and send a WILL ECHO
602 * so that we are properly in character mode and
603 * all is well.
604 */
605 break;
606 #ifdef LINEMODE
607 case TELOPT_LINEMODE:
608 # ifdef KLUDGELINEMODE
609 /*
610 * Note client's desire to use linemode.
611 */
612 lmodetype = REAL_LINEMODE;
613 # endif /* KLUDGELINEMODE */
614 func = doclientstat;
615 break;
616 #endif /* LINEMODE */
617
618 #ifdef AUTHENTICATION
619 case TELOPT_AUTHENTICATION:
620 func = auth_request;
621 break;
622 #endif
623
624 #ifdef ENCRYPTION
625 case TELOPT_ENCRYPT:
626 func = encrypt_send_support;
627 break;
628 #endif /* ENCRYPTION */
629 case TELOPT_LFLOW:
630 func = flowstat;
631 break;
632 }
633 }
634 }
635 set_his_state_will(option);
636 if (func)
637 (*func)();
638 } /* end of willoption */
639
640 void
send_dont(int option,int init)641 send_dont(int option, int init)
642 {
643 if (init) {
644 if ((do_dont_resp[option] == 0 && his_state_is_wont(option)) ||
645 his_want_state_is_wont(option))
646 return;
647 set_his_want_state_wont(option);
648 do_dont_resp[option]++;
649 }
650 output_data((const char *)dont, option);
651
652 DIAG(TD_OPTIONS, printoption("td: send dont", option));
653 }
654
655 void
wontoption(int option)656 wontoption(int option)
657 {
658 /*
659 * Process client input.
660 */
661
662 DIAG(TD_OPTIONS, printoption("td: recv wont", option));
663
664 if (do_dont_resp[option]) {
665 do_dont_resp[option]--;
666 if (do_dont_resp[option] && his_state_is_wont(option))
667 do_dont_resp[option]--;
668 }
669 if (do_dont_resp[option] == 0) {
670 if (his_want_state_is_will(option)) {
671 /* it is always ok to change to negative state */
672 switch (option) {
673 case TELOPT_ECHO:
674 not42 = 1; /* doesn't seem to be a 4.2 system */
675 break;
676
677 case TELOPT_BINARY:
678 init_termbuf();
679 tty_binaryin(0);
680 set_termbuf();
681 break;
682
683 #ifdef LINEMODE
684 case TELOPT_LINEMODE:
685 # ifdef KLUDGELINEMODE
686 /*
687 * If real linemode is supported, then client is
688 * asking to turn linemode off.
689 */
690 if (lmodetype != REAL_LINEMODE)
691 break;
692 lmodetype = KLUDGE_LINEMODE;
693 # endif /* KLUDGELINEMODE */
694 clientstat(TELOPT_LINEMODE, WONT, 0);
695 break;
696 #endif /* LINEMODE */
697
698 case TELOPT_TM:
699 /*
700 * If we get a WONT TM, and had sent a DO TM,
701 * don't respond with a DONT TM, just leave it
702 * as is. Short circut the state machine to
703 * achive this.
704 */
705 set_his_want_state_wont(TELOPT_TM);
706 return;
707
708 case TELOPT_LFLOW:
709 /*
710 * If we are not going to support flow control
711 * option, then let peer know that we can't
712 * change the flow control characters.
713 */
714 slctab[SLC_XON].defset.flag &= ~SLC_LEVELBITS;
715 slctab[SLC_XON].defset.flag |= SLC_CANTCHANGE;
716 slctab[SLC_XOFF].defset.flag &= ~SLC_LEVELBITS;
717 slctab[SLC_XOFF].defset.flag |= SLC_CANTCHANGE;
718 break;
719
720 #ifdef AUTHENTICATION
721 case TELOPT_AUTHENTICATION:
722 auth_finished(0, AUTH_REJECT);
723 break;
724 #endif
725
726 /*
727 * For options that we might spin waiting for
728 * sub-negotiation, if the client turns off the
729 * option rather than responding to the request,
730 * we have to treat it here as if we got a response
731 * to the sub-negotiation, (by updating the timers)
732 * so that we'll break out of the loop.
733 */
734 case TELOPT_TTYPE:
735 settimer(ttypesubopt);
736 break;
737
738 case TELOPT_TSPEED:
739 settimer(tspeedsubopt);
740 break;
741
742 case TELOPT_XDISPLOC:
743 settimer(xdisplocsubopt);
744 break;
745
746 case TELOPT_OLD_ENVIRON:
747 settimer(oenvironsubopt);
748 break;
749
750 case TELOPT_NEW_ENVIRON:
751 settimer(environsubopt);
752 break;
753
754 default:
755 break;
756 }
757 set_his_want_state_wont(option);
758 if (his_state_is_will(option))
759 send_dont(option, 0);
760 } else {
761 switch (option) {
762 case TELOPT_TM:
763 #if defined(LINEMODE) && defined(KLUDGELINEMODE)
764 if (lmodetype < NO_AUTOKLUDGE) {
765 lmodetype = NO_LINEMODE;
766 clientstat(TELOPT_LINEMODE, WONT, 0);
767 send_will(TELOPT_SGA, 1);
768 send_will(TELOPT_ECHO, 1);
769 }
770 #endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
771 break;
772
773 #ifdef AUTHENTICATION
774 case TELOPT_AUTHENTICATION:
775 auth_finished(0, AUTH_REJECT);
776 break;
777 #endif
778 default:
779 break;
780 }
781 }
782 }
783 set_his_state_wont(option);
784
785 } /* end of wontoption */
786
787 void
send_will(int option,int init)788 send_will(int option, int init)
789 {
790 if (init) {
791 if ((will_wont_resp[option] == 0 && my_state_is_will(option))||
792 my_want_state_is_will(option))
793 return;
794 set_my_want_state_will(option);
795 will_wont_resp[option]++;
796 }
797 output_data((const char *)will, option);
798
799 DIAG(TD_OPTIONS, printoption("td: send will", option));
800 }
801
802 #if !defined(LINEMODE) || !defined(KLUDGELINEMODE)
803 /*
804 * When we get a DONT SGA, we will try once to turn it
805 * back on. If the other side responds DONT SGA, we
806 * leave it at that. This is so that when we talk to
807 * clients that understand KLUDGELINEMODE but not LINEMODE,
808 * we'll keep them in char-at-a-time mode.
809 */
810 int turn_on_sga = 0;
811 #endif
812
813 void
dooption(int option)814 dooption(int option)
815 {
816 int changeok = 0;
817
818 /*
819 * Process client input.
820 */
821
822 DIAG(TD_OPTIONS, printoption("td: recv do", option));
823
824 if (will_wont_resp[option]) {
825 will_wont_resp[option]--;
826 if (will_wont_resp[option] && my_state_is_will(option))
827 will_wont_resp[option]--;
828 }
829 if ((will_wont_resp[option] == 0) && (my_want_state_is_wont(option))) {
830 switch (option) {
831 case TELOPT_ECHO:
832 #ifdef LINEMODE
833 # ifdef KLUDGELINEMODE
834 if (lmodetype == NO_LINEMODE)
835 # else
836 if (his_state_is_wont(TELOPT_LINEMODE))
837 # endif
838 #endif
839 {
840 init_termbuf();
841 tty_setecho(1);
842 set_termbuf();
843 }
844 changeok++;
845 break;
846
847 case TELOPT_BINARY:
848 init_termbuf();
849 tty_binaryout(1);
850 set_termbuf();
851 changeok++;
852 break;
853
854 case TELOPT_SGA:
855 #if defined(LINEMODE) && defined(KLUDGELINEMODE)
856 /*
857 * If kludge linemode is in use, then we must
858 * process an incoming do SGA for linemode
859 * purposes.
860 */
861 if (lmodetype == KLUDGE_LINEMODE) {
862 /*
863 * Receipt of "do SGA" in kludge
864 * linemode is the peer asking us to
865 * turn off linemode. Make note of
866 * the request.
867 */
868 clientstat(TELOPT_LINEMODE, WONT, 0);
869 /*
870 * If linemode did not get turned off
871 * then don't tell peer that we did.
872 * Breaking here forces a wont SGA to
873 * be returned.
874 */
875 if (linemode)
876 break;
877 }
878 #else
879 turn_on_sga = 0;
880 #endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
881 changeok++;
882 break;
883
884 case TELOPT_STATUS:
885 changeok++;
886 break;
887
888 case TELOPT_TM:
889 /*
890 * Special case for TM. We send a WILL, but
891 * pretend we sent a WONT.
892 */
893 send_will(option, 0);
894 set_my_want_state_wont(option);
895 set_my_state_wont(option);
896 return;
897
898 case TELOPT_LOGOUT:
899 /*
900 * When we get a LOGOUT option, respond
901 * with a WILL LOGOUT, make sure that
902 * it gets written out to the network,
903 * and then just go away...
904 */
905 set_my_want_state_will(TELOPT_LOGOUT);
906 send_will(TELOPT_LOGOUT, 0);
907 set_my_state_will(TELOPT_LOGOUT);
908 (void)netflush();
909 cleanup(0);
910 /* NOT REACHED */
911 break;
912
913 #ifdef ENCRYPTION
914 case TELOPT_ENCRYPT:
915 changeok++;
916 break;
917 #endif /* ENCRYPTION */
918 case TELOPT_LINEMODE:
919 case TELOPT_TTYPE:
920 case TELOPT_NAWS:
921 case TELOPT_TSPEED:
922 case TELOPT_LFLOW:
923 case TELOPT_XDISPLOC:
924 #ifdef TELOPT_ENVIRON
925 case TELOPT_NEW_ENVIRON:
926 #endif
927 case TELOPT_OLD_ENVIRON:
928 default:
929 break;
930 }
931 if (changeok) {
932 set_my_want_state_will(option);
933 send_will(option, 0);
934 } else {
935 will_wont_resp[option]++;
936 send_wont(option, 0);
937 }
938 }
939 set_my_state_will(option);
940
941 } /* end of dooption */
942
943 void
send_wont(int option,int init)944 send_wont(int option, int init)
945 {
946 if (init) {
947 if ((will_wont_resp[option] == 0 && my_state_is_wont(option)) ||
948 my_want_state_is_wont(option))
949 return;
950 set_my_want_state_wont(option);
951 will_wont_resp[option]++;
952 }
953 output_data((const char *)wont, option);
954
955 DIAG(TD_OPTIONS, printoption("td: send wont", option));
956 }
957
958 void
dontoption(int option)959 dontoption(int option)
960 {
961 /*
962 * Process client input.
963 */
964
965
966 DIAG(TD_OPTIONS, printoption("td: recv dont", option));
967
968 if (will_wont_resp[option]) {
969 will_wont_resp[option]--;
970 if (will_wont_resp[option] && my_state_is_wont(option))
971 will_wont_resp[option]--;
972 }
973 if ((will_wont_resp[option] == 0) && (my_want_state_is_will(option))) {
974 switch (option) {
975 case TELOPT_BINARY:
976 init_termbuf();
977 tty_binaryout(0);
978 set_termbuf();
979 break;
980
981 case TELOPT_ECHO: /* we should stop echoing */
982 #ifdef LINEMODE
983 # ifdef KLUDGELINEMODE
984 if ((lmodetype != REAL_LINEMODE) &&
985 (lmodetype != KLUDGE_LINEMODE))
986 # else
987 if (his_state_is_wont(TELOPT_LINEMODE))
988 # endif
989 #endif
990 {
991 init_termbuf();
992 tty_setecho(0);
993 set_termbuf();
994 }
995 break;
996
997 case TELOPT_SGA:
998 #if defined(LINEMODE) && defined(KLUDGELINEMODE)
999 /*
1000 * If kludge linemode is in use, then we
1001 * must process an incoming do SGA for
1002 * linemode purposes.
1003 */
1004 if ((lmodetype == KLUDGE_LINEMODE) ||
1005 (lmodetype == KLUDGE_OK)) {
1006 /*
1007 * The client is asking us to turn
1008 * linemode on.
1009 */
1010 lmodetype = KLUDGE_LINEMODE;
1011 clientstat(TELOPT_LINEMODE, WILL, 0);
1012 /*
1013 * If we did not turn line mode on,
1014 * then what do we say? Will SGA?
1015 * This violates design of telnet.
1016 * Gross. Very Gross.
1017 */
1018 }
1019 break;
1020 #else
1021 set_my_want_state_wont(option);
1022 if (my_state_is_will(option))
1023 send_wont(option, 0);
1024 set_my_state_wont(option);
1025 if (turn_on_sga ^= 1)
1026 send_will(option, 1);
1027 return;
1028 #endif /* defined(LINEMODE) && defined(KLUDGELINEMODE) */
1029
1030 default:
1031 break;
1032 }
1033
1034 set_my_want_state_wont(option);
1035 if (my_state_is_will(option))
1036 send_wont(option, 0);
1037 }
1038 set_my_state_wont(option);
1039
1040 } /* end of dontoption */
1041
1042 #ifdef ENV_HACK
1043 int env_ovar = -1;
1044 int env_ovalue = -1;
1045 #else /* ENV_HACK */
1046 # define env_ovar OLD_ENV_VAR
1047 # define env_ovalue OLD_ENV_VALUE
1048 #endif /* ENV_HACK */
1049
1050 /*
1051 * suboption()
1052 *
1053 * Look at the sub-option buffer, and try to be helpful to the other
1054 * side.
1055 *
1056 * Currently we recognize:
1057 *
1058 * Terminal type is
1059 * Linemode
1060 * Window size
1061 * Terminal speed
1062 */
1063 void
suboption(void)1064 suboption(void)
1065 {
1066 int subchar;
1067
1068 DIAG(TD_OPTIONS, {netflush(); printsub('<', subpointer, SB_LEN()+2);});
1069
1070 subchar = SB_GET();
1071 switch (subchar) {
1072 case TELOPT_TSPEED: {
1073 int xspeed, rspeed;
1074
1075 if (his_state_is_wont(TELOPT_TSPEED)) /* Ignore if option disabled */
1076 break;
1077
1078 settimer(tspeedsubopt);
1079
1080 if (SB_EOF() || SB_GET() != TELQUAL_IS)
1081 return;
1082
1083 xspeed = atoi((char *)subpointer);
1084
1085 while (SB_GET() != ',' && !SB_EOF());
1086 if (SB_EOF())
1087 return;
1088
1089 rspeed = atoi((char *)subpointer);
1090 clientstat(TELOPT_TSPEED, xspeed, rspeed);
1091
1092 break;
1093
1094 } /* end of case TELOPT_TSPEED */
1095
1096 case TELOPT_TTYPE: { /* Yaaaay! */
1097 static char terminalname[41];
1098
1099 if (his_state_is_wont(TELOPT_TTYPE)) /* Ignore if option disabled */
1100 break;
1101 settimer(ttypesubopt);
1102
1103 if (SB_EOF() || SB_GET() != TELQUAL_IS) {
1104 return; /* ??? XXX but, this is the most robust */
1105 }
1106
1107 terminaltype = terminalname;
1108
1109 while ((terminaltype < (terminalname + sizeof terminalname-1)) &&
1110 !SB_EOF()) {
1111 int c;
1112
1113 c = SB_GET();
1114 if (isupper(c)) {
1115 c = tolower(c);
1116 }
1117 *terminaltype++ = c; /* accumulate name */
1118 }
1119 *terminaltype = 0;
1120 terminaltype = terminalname;
1121 break;
1122 } /* end of case TELOPT_TTYPE */
1123
1124 case TELOPT_NAWS: {
1125 int xwinsize, ywinsize;
1126
1127 if (his_state_is_wont(TELOPT_NAWS)) /* Ignore if option disabled */
1128 break;
1129
1130 if (SB_EOF())
1131 return;
1132 xwinsize = SB_GET() << 8;
1133 if (SB_EOF())
1134 return;
1135 xwinsize |= SB_GET();
1136 if (SB_EOF())
1137 return;
1138 ywinsize = SB_GET() << 8;
1139 if (SB_EOF())
1140 return;
1141 ywinsize |= SB_GET();
1142 clientstat(TELOPT_NAWS, xwinsize, ywinsize);
1143
1144 break;
1145
1146 } /* end of case TELOPT_NAWS */
1147
1148 #ifdef LINEMODE
1149 case TELOPT_LINEMODE: {
1150 int request;
1151
1152 if (his_state_is_wont(TELOPT_LINEMODE)) /* Ignore if option disabled */
1153 break;
1154 /*
1155 * Process linemode suboptions.
1156 */
1157 if (SB_EOF())
1158 break; /* garbage was sent */
1159 request = SB_GET(); /* get will/wont */
1160
1161 if (SB_EOF())
1162 break; /* another garbage check */
1163
1164 if (request == LM_SLC) { /* SLC is not preceeded by WILL or WONT */
1165 /*
1166 * Process suboption buffer of slc's
1167 */
1168 start_slc(1);
1169 do_opt_slc(subpointer, subend - subpointer);
1170 (void) end_slc(0);
1171 break;
1172 } else if (request == LM_MODE) {
1173 if (SB_EOF())
1174 return;
1175 useeditmode = SB_GET(); /* get mode flag */
1176 clientstat(LM_MODE, 0, 0);
1177 break;
1178 }
1179
1180 if (SB_EOF())
1181 break;
1182 switch (SB_GET()) { /* what suboption? */
1183 case LM_FORWARDMASK:
1184 /*
1185 * According to spec, only server can send request for
1186 * forwardmask, and client can only return a positive response.
1187 * So don't worry about it.
1188 */
1189
1190 default:
1191 break;
1192 }
1193 break;
1194 } /* end of case TELOPT_LINEMODE */
1195 #endif
1196 case TELOPT_STATUS: {
1197 int mode;
1198
1199 if (SB_EOF())
1200 break;
1201 mode = SB_GET();
1202 switch (mode) {
1203 case TELQUAL_SEND:
1204 if (my_state_is_will(TELOPT_STATUS))
1205 send_status();
1206 break;
1207
1208 case TELQUAL_IS:
1209 break;
1210
1211 default:
1212 break;
1213 }
1214 break;
1215 } /* end of case TELOPT_STATUS */
1216
1217 case TELOPT_XDISPLOC: {
1218 if (SB_EOF() || SB_GET() != TELQUAL_IS)
1219 return;
1220 settimer(xdisplocsubopt);
1221 subpointer[SB_LEN()] = '\0';
1222 (void)setenv("DISPLAY", (char *)subpointer, 1);
1223 break;
1224 } /* end of case TELOPT_XDISPLOC */
1225
1226 #ifdef TELOPT_NEW_ENVIRON
1227 case TELOPT_NEW_ENVIRON:
1228 #endif
1229 case TELOPT_OLD_ENVIRON: {
1230 int c;
1231 char *cp, *varp, *valp;
1232
1233 if (SB_EOF())
1234 return;
1235 c = SB_GET();
1236 if (c == TELQUAL_IS) {
1237 if (subchar == TELOPT_OLD_ENVIRON)
1238 settimer(oenvironsubopt);
1239 else
1240 settimer(environsubopt);
1241 } else if (c != TELQUAL_INFO) {
1242 return;
1243 }
1244
1245 #ifdef TELOPT_NEW_ENVIRON
1246 if (subchar == TELOPT_NEW_ENVIRON) {
1247 while (!SB_EOF()) {
1248 c = SB_GET();
1249 if ((c == NEW_ENV_VAR) || (c == ENV_USERVAR))
1250 break;
1251 }
1252 } else
1253 #endif
1254 {
1255 #ifdef ENV_HACK
1256 /*
1257 * We only want to do this if we haven't already decided
1258 * whether or not the other side has its VALUE and VAR
1259 * reversed.
1260 */
1261 if (env_ovar < 0) {
1262 int last = -1; /* invalid value */
1263 int empty = 0;
1264 int got_var = 0, got_value = 0, got_uservar = 0;
1265
1266 /*
1267 * The other side might have its VALUE and VAR values
1268 * reversed. To be interoperable, we need to determine
1269 * which way it is. If the first recognized character
1270 * is a VAR or VALUE, then that will tell us what
1271 * type of client it is. If the fist recognized
1272 * character is a USERVAR, then we continue scanning
1273 * the suboption looking for two consecutive
1274 * VAR or VALUE fields. We should not get two
1275 * consecutive VALUE fields, so finding two
1276 * consecutive VALUE or VAR fields will tell us
1277 * what the client is.
1278 */
1279 SB_SAVE();
1280 while (!SB_EOF()) {
1281 c = SB_GET();
1282 switch(c) {
1283 case OLD_ENV_VAR:
1284 if (last < 0 || last == OLD_ENV_VAR
1285 || (empty && (last == OLD_ENV_VALUE)))
1286 goto env_ovar_ok;
1287 got_var++;
1288 last = OLD_ENV_VAR;
1289 break;
1290 case OLD_ENV_VALUE:
1291 if (last < 0 || last == OLD_ENV_VALUE
1292 || (empty && (last == OLD_ENV_VAR)))
1293 goto env_ovar_wrong;
1294 got_value++;
1295 last = OLD_ENV_VALUE;
1296 break;
1297 case ENV_USERVAR:
1298 /* count strings of USERVAR as one */
1299 if (last != ENV_USERVAR)
1300 got_uservar++;
1301 if (empty) {
1302 if (last == OLD_ENV_VALUE)
1303 goto env_ovar_ok;
1304 if (last == OLD_ENV_VAR)
1305 goto env_ovar_wrong;
1306 }
1307 last = ENV_USERVAR;
1308 break;
1309 case ENV_ESC:
1310 if (!SB_EOF())
1311 c = SB_GET();
1312 /* FALLTHROUGH */
1313 default:
1314 empty = 0;
1315 continue;
1316 }
1317 empty = 1;
1318 }
1319 if (empty) {
1320 if (last == OLD_ENV_VALUE)
1321 goto env_ovar_ok;
1322 if (last == OLD_ENV_VAR)
1323 goto env_ovar_wrong;
1324 }
1325 /*
1326 * Ok, the first thing was a USERVAR, and there
1327 * are not two consecutive VAR or VALUE commands,
1328 * and none of the VAR or VALUE commands are empty.
1329 * If the client has sent us a well-formed option,
1330 * then the number of VALUEs received should always
1331 * be less than or equal to the number of VARs and
1332 * USERVARs received.
1333 *
1334 * If we got exactly as many VALUEs as VARs and
1335 * USERVARs, the client has the same definitions.
1336 *
1337 * If we got exactly as many VARs as VALUEs and
1338 * USERVARS, the client has reversed definitions.
1339 */
1340 if (got_uservar + got_var == got_value) {
1341 env_ovar_ok:
1342 env_ovar = OLD_ENV_VAR;
1343 env_ovalue = OLD_ENV_VALUE;
1344 } else if (got_uservar + got_value == got_var) {
1345 env_ovar_wrong:
1346 env_ovar = OLD_ENV_VALUE;
1347 env_ovalue = OLD_ENV_VAR;
1348 DIAG(TD_OPTIONS,
1349 output_data("ENVIRON VALUE and VAR are reversed!\r\n"));
1350
1351 }
1352 }
1353 SB_RESTORE();
1354 #endif
1355
1356 while (!SB_EOF()) {
1357 c = SB_GET();
1358 if ((c == env_ovar) || (c == ENV_USERVAR))
1359 break;
1360 }
1361 }
1362
1363 if (SB_EOF())
1364 return;
1365
1366 cp = varp = (char *)subpointer;
1367 valp = 0;
1368
1369 while (!SB_EOF()) {
1370 c = SB_GET();
1371 if (subchar == TELOPT_OLD_ENVIRON) {
1372 if (c == env_ovar)
1373 c = NEW_ENV_VAR;
1374 else if (c == env_ovalue)
1375 c = NEW_ENV_VALUE;
1376 }
1377 switch (c) {
1378
1379 case NEW_ENV_VALUE:
1380 *cp = '\0';
1381 cp = valp = (char *)subpointer;
1382 break;
1383
1384 case NEW_ENV_VAR:
1385 case ENV_USERVAR:
1386 *cp = '\0';
1387 if (valp)
1388 (void)setenv(varp, valp, 1);
1389 else
1390 unsetenv(varp);
1391 cp = varp = (char *)subpointer;
1392 valp = 0;
1393 break;
1394
1395 case ENV_ESC:
1396 if (SB_EOF())
1397 break;
1398 c = SB_GET();
1399 /* FALLTHROUGH */
1400 default:
1401 *cp++ = c;
1402 break;
1403 }
1404 }
1405 *cp = '\0';
1406 if (valp)
1407 (void)setenv(varp, valp, 1);
1408 else
1409 unsetenv(varp);
1410 break;
1411 } /* end of case TELOPT_NEW_ENVIRON */
1412 #ifdef AUTHENTICATION
1413 case TELOPT_AUTHENTICATION:
1414 if (SB_EOF())
1415 break;
1416 switch(SB_GET()) {
1417 case TELQUAL_SEND:
1418 case TELQUAL_REPLY:
1419 /*
1420 * These are sent by us and cannot be sent by
1421 * the client.
1422 */
1423 break;
1424 case TELQUAL_IS:
1425 auth_is(subpointer, SB_LEN());
1426 break;
1427 case TELQUAL_NAME:
1428 auth_name(subpointer, SB_LEN());
1429 break;
1430 }
1431 break;
1432 #endif
1433 #ifdef ENCRYPTION
1434 case TELOPT_ENCRYPT:
1435 if (SB_EOF())
1436 break;
1437 switch(SB_GET()) {
1438 case ENCRYPT_SUPPORT:
1439 encrypt_support(subpointer, SB_LEN());
1440 break;
1441 case ENCRYPT_IS:
1442 encrypt_is(subpointer, SB_LEN());
1443 break;
1444 case ENCRYPT_REPLY:
1445 encrypt_reply(subpointer, SB_LEN());
1446 break;
1447 case ENCRYPT_START:
1448 encrypt_start(subpointer, SB_LEN());
1449 break;
1450 case ENCRYPT_END:
1451 encrypt_end();
1452 break;
1453 case ENCRYPT_REQSTART:
1454 encrypt_request_start(subpointer, SB_LEN());
1455 break;
1456 case ENCRYPT_REQEND:
1457 /*
1458 * We can always send an REQEND so that we cannot
1459 * get stuck encrypting. We should only get this
1460 * if we have been able to get in the correct mode
1461 * anyhow.
1462 */
1463 encrypt_request_end();
1464 break;
1465 case ENCRYPT_ENC_KEYID:
1466 encrypt_enc_keyid(subpointer, SB_LEN());
1467 break;
1468 case ENCRYPT_DEC_KEYID:
1469 encrypt_dec_keyid(subpointer, SB_LEN());
1470 break;
1471 default:
1472 break;
1473 }
1474 break;
1475 #endif /* ENCRYPTION */
1476
1477 default:
1478 break;
1479 } /* end of switch */
1480
1481 } /* end of suboption */
1482
1483 static void
doclientstat(void)1484 doclientstat(void)
1485 {
1486 clientstat(TELOPT_LINEMODE, WILL, 0);
1487 }
1488
1489 #define ADD(c) *ncp++ = c
1490 #define ADD_DATA(c) { *ncp++ = c; if (c == SE || c == IAC) *ncp++ = c; }
1491 void
send_status(void)1492 send_status(void)
1493 {
1494 unsigned char statusbuf[256];
1495 unsigned char *ncp;
1496 unsigned char i;
1497
1498 ncp = statusbuf;
1499
1500 netflush(); /* get rid of anything waiting to go out */
1501
1502 ADD(IAC);
1503 ADD(SB);
1504 ADD(TELOPT_STATUS);
1505 ADD(TELQUAL_IS);
1506
1507 /*
1508 * We check the want_state rather than the current state,
1509 * because if we received a DO/WILL for an option that we
1510 * don't support, and the other side didn't send a DONT/WONT
1511 * in response to our WONT/DONT, then the "state" will be
1512 * WILL/DO, and the "want_state" will be WONT/DONT. We
1513 * need to go by the latter.
1514 */
1515 for (i = 0; i < (unsigned char)NTELOPTS; i++) {
1516 if (my_want_state_is_will(i)) {
1517 ADD(WILL);
1518 ADD_DATA(i);
1519 if (i == IAC)
1520 ADD(IAC);
1521 }
1522 if (his_want_state_is_will(i)) {
1523 ADD(DO);
1524 ADD_DATA(i);
1525 if (i == IAC)
1526 ADD(IAC);
1527 }
1528 }
1529
1530 if (his_want_state_is_will(TELOPT_LFLOW)) {
1531 ADD(SB);
1532 ADD(TELOPT_LFLOW);
1533 if (flowmode) {
1534 ADD(LFLOW_ON);
1535 } else {
1536 ADD(LFLOW_OFF);
1537 }
1538 ADD(SE);
1539
1540 if (restartany >= 0) {
1541 ADD(SB);
1542 ADD(TELOPT_LFLOW);
1543 if (restartany) {
1544 ADD(LFLOW_RESTART_ANY);
1545 } else {
1546 ADD(LFLOW_RESTART_XON);
1547 }
1548 ADD(SE);
1549 }
1550 }
1551
1552 #ifdef LINEMODE
1553 if (his_want_state_is_will(TELOPT_LINEMODE)) {
1554 unsigned char *cp, *cpe;
1555 int len;
1556
1557 ADD(SB);
1558 ADD(TELOPT_LINEMODE);
1559 ADD(LM_MODE);
1560 ADD_DATA(editmode);
1561 ADD(SE);
1562
1563 ADD(SB);
1564 ADD(TELOPT_LINEMODE);
1565 ADD(LM_SLC);
1566 start_slc(0);
1567 send_slc();
1568 len = end_slc(&cp);
1569 for (cpe = cp + len; cp < cpe; cp++)
1570 ADD_DATA(*cp);
1571 ADD(SE);
1572 }
1573 #endif /* LINEMODE */
1574
1575 ADD(IAC);
1576 ADD(SE);
1577
1578 output_datalen(statusbuf, ncp - statusbuf);
1579 netflush(); /* Send it on its way */
1580
1581 DIAG(TD_OPTIONS,
1582 {printsub('>', statusbuf, ncp - statusbuf); netflush();});
1583 }
1584
1585 /*
1586 * This function appends data to nfrontp and advances nfrontp.
1587 * Returns the number of characters written altogether (the
1588 * buffer may have been flushed in the process).
1589 */
1590
1591 int
output_data(const char * format,...)1592 output_data(const char *format, ...)
1593 {
1594 va_list args;
1595 int len;
1596 char *buf;
1597
1598 va_start(args, format);
1599 if ((len = vasprintf(&buf, format, args)) == -1) {
1600 va_end(args);
1601 return -1;
1602 }
1603 output_datalen(buf, len);
1604 va_end(args);
1605 free(buf);
1606 return (len);
1607 }
1608
1609 void
output_datalen(const char * buf,int len)1610 output_datalen(const char *buf, int len)
1611 {
1612 int remaining, copied;
1613
1614 remaining = BUFSIZ - (nfrontp - netobuf);
1615 while (len > 0) {
1616 /* Free up enough space if the room is too low*/
1617 if ((len > BUFSIZ ? BUFSIZ : len) > remaining) {
1618 netflush();
1619 remaining = BUFSIZ - (nfrontp - netobuf);
1620 }
1621
1622 /* Copy out as much as will fit */
1623 copied = remaining > len ? len : remaining;
1624 memmove(nfrontp, buf, copied);
1625 nfrontp += copied;
1626 len -= copied;
1627 remaining -= copied;
1628 buf += copied;
1629 }
1630 return;
1631 }
1632