source: MondoRescue/branches/2.2.5/mindi-busybox/networking/telnet.c@ 1765

Last change on this file since 1765 was 1765, checked in by Bruno Cornec, 16 years ago

Update to busybox 1.7.2
File size: 12.1 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * telnet implementation for busybox
4 *
5 * Author: Tomi Ollila <too@iki.fi>
6 * Copyright (C) 1994-2000 by Tomi Ollila
7 *
8 * Created: Thu Apr 7 13:29:41 1994 too
9 * Last modified: Fri Jun 9 14:34:24 2000 too
10 *
11 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
12 *
13 * HISTORY
14 * Revision 3.1 1994/04/17 11:31:54 too
15 * initial revision
16 * Modified 2000/06/13 for inclusion into BusyBox by Erik Andersen <andersen@codepoet.org>
17 * Modified 2001/05/07 to add ability to pass TTYPE to remote host by Jim McQuillan
18 * <jam@ltsp.org>
19 * Modified 2004/02/11 to add ability to pass the USER variable to remote host
20 * by Fernando Silveira <swrh@gmx.net>
21 *
22 */
23
24#include <termios.h>
25#include <arpa/telnet.h>
26#include <netinet/in.h>
27#include "libbb.h"
28
29#ifdef DOTRACE
30#define TRACE(x, y) do { if (x) printf y; } while (0)
31#else
32#define TRACE(x, y)
33#endif
34
35enum {
36 DATABUFSIZE = 128,
37 IACBUFSIZE = 128,
38
39 CHM_TRY = 0,
40 CHM_ON = 1,
41 CHM_OFF = 2,
42
43 UF_ECHO = 0x01,
44 UF_SGA = 0x02,
45
46 TS_0 = 1,
47 TS_IAC = 2,
48 TS_OPT = 3,
49 TS_SUB1 = 4,
50 TS_SUB2 = 5,
51};
52
53typedef unsigned char byte;
54
55struct globals {
56 int netfd; /* console fd:s are 0 and 1 (and 2) */
57 short iaclen; /* could even use byte */
58 byte telstate; /* telnet negotiation state from network input */
59 byte telwish; /* DO, DONT, WILL, WONT */
60 byte charmode;
61 byte telflags;
62 byte gotsig;
63 byte do_termios;
64#if ENABLE_FEATURE_TELNET_TTYPE
65 char *ttype;
66#endif
67#if ENABLE_FEATURE_TELNET_AUTOLOGIN
68 const char *autologin;
69#endif
70#if ENABLE_FEATURE_AUTOWIDTH
71 int win_width, win_height;
72#endif
73 /* same buffer used both for network and console read/write */
74 char buf[DATABUFSIZE];
75 /* buffer to handle telnet negotiations */
76 char iacbuf[IACBUFSIZE];
77 struct termios termios_def;
78 struct termios termios_raw;
79};
80#define G (*(struct globals*)&bb_common_bufsiz1)
81void BUG_telnet_globals_too_big(void);
82#define INIT_G() do { \
83 if (sizeof(G) > COMMON_BUFSIZE) \
84 BUG_telnet_globals_too_big(); \
85 /* memset(&G, 0, sizeof G); - already is */ \
86} while (0)
87
88/* Function prototypes */
89static void rawmode(void);
90static void cookmode(void);
91static void do_linemode(void);
92static void will_charmode(void);
93static void telopt(byte c);
94static int subneg(byte c);
95
96static void iacflush(void)
97{
98 write(G.netfd, G.iacbuf, G.iaclen);
99 G.iaclen = 0;
100}
101
102#define write_str(fd, str) write(fd, str, sizeof(str) - 1)
103
104static void doexit(int ev)
105{
106 cookmode();
107 exit(ev);
108}
109
110static void conescape(void)
111{
112 char b;
113
114 if (G.gotsig) /* came from line mode... go raw */
115 rawmode();
116
117 write_str(1, "\r\nConsole escape. Commands are:\r\n\n"
118 " l go to line mode\r\n"
119 " c go to character mode\r\n"
120 " z suspend telnet\r\n"
121 " e exit telnet\r\n");
122
123 if (read(0, &b, 1) <= 0)
124 doexit(1);
125
126 switch (b) {
127 case 'l':
128 if (!G.gotsig) {
129 do_linemode();
130 goto rrturn;
131 }
132 break;
133 case 'c':
134 if (G.gotsig) {
135 will_charmode();
136 goto rrturn;
137 }
138 break;
139 case 'z':
140 cookmode();
141 kill(0, SIGTSTP);
142 rawmode();
143 break;
144 case 'e':
145 doexit(0);
146 }
147
148 write_str(1, "continuing...\r\n");
149
150 if (G.gotsig)
151 cookmode();
152
153 rrturn:
154 G.gotsig = 0;
155
156}
157
158static void handlenetoutput(int len)
159{
160 /* here we could do smart tricks how to handle 0xFF:s in output
161 * stream like writing twice every sequence of FF:s (thus doing
162 * many write()s. But I think interactive telnet application does
163 * not need to be 100% 8-bit clean, so changing every 0xff:s to
164 * 0x7f:s
165 *
166 * 2002-mar-21, Przemyslaw Czerpak (druzus@polbox.com)
167 * I don't agree.
168 * first - I cannot use programs like sz/rz
169 * second - the 0x0D is sent as one character and if the next
170 * char is 0x0A then it's eaten by a server side.
171 * third - whay doy you have to make 'many write()s'?
172 * I don't understand.
173 * So I implemented it. It's realy useful for me. I hope that
174 * others people will find it interesting to.
175 */
176
177 int i, j;
178 byte * p = (byte*)G.buf;
179 byte outbuf[4*DATABUFSIZE];
180
181 for (i = len, j = 0; i > 0; i--, p++)
182 {
183 if (*p == 0x1d)
184 {
185 conescape();
186 return;
187 }
188 outbuf[j++] = *p;
189 if (*p == 0xff)
190 outbuf[j++] = 0xff;
191 else if (*p == 0x0d)
192 outbuf[j++] = 0x00;
193 }
194 if (j > 0)
195 write(G.netfd, outbuf, j);
196}
197
198static void handlenetinput(int len)
199{
200 int i;
201 int cstart = 0;
202
203 for (i = 0; i < len; i++)
204 {
205 byte c = G.buf[i];
206
207 if (G.telstate == 0) /* most of the time state == 0 */
208 {
209 if (c == IAC)
210 {
211 cstart = i;
212 G.telstate = TS_IAC;
213 }
214 }
215 else
216 switch (G.telstate)
217 {
218 case TS_0:
219 if (c == IAC)
220 G.telstate = TS_IAC;
221 else
222 G.buf[cstart++] = c;
223 break;
224
225 case TS_IAC:
226 if (c == IAC) /* IAC IAC -> 0xFF */
227 {
228 G.buf[cstart++] = c;
229 G.telstate = TS_0;
230 break;
231 }
232 /* else */
233 switch (c)
234 {
235 case SB:
236 G.telstate = TS_SUB1;
237 break;
238 case DO:
239 case DONT:
240 case WILL:
241 case WONT:
242 G.telwish = c;
243 G.telstate = TS_OPT;
244 break;
245 default:
246 G.telstate = TS_0; /* DATA MARK must be added later */
247 }
248 break;
249 case TS_OPT: /* WILL, WONT, DO, DONT */
250 telopt(c);
251 G.telstate = TS_0;
252 break;
253 case TS_SUB1: /* Subnegotiation */
254 case TS_SUB2: /* Subnegotiation */
255 if (subneg(c))
256 G.telstate = TS_0;
257 break;
258 }
259 }
260 if (G.telstate)
261 {
262 if (G.iaclen) iacflush();
263 if (G.telstate == TS_0) G.telstate = 0;
264
265 len = cstart;
266 }
267
268 if (len)
269 write(1, G.buf, len);
270}
271
272static void putiac(int c)
273{
274 G.iacbuf[G.iaclen++] = c;
275}
276
277static void putiac2(byte wwdd, byte c)
278{
279 if (G.iaclen + 3 > IACBUFSIZE)
280 iacflush();
281
282 putiac(IAC);
283 putiac(wwdd);
284 putiac(c);
285}
286
287#if ENABLE_FEATURE_TELNET_TTYPE
288static void putiac_subopt(byte c, char *str)
289{
290 int len = strlen(str) + 6; // ( 2 + 1 + 1 + strlen + 2 )
291
292 if (G.iaclen + len > IACBUFSIZE)
293 iacflush();
294
295 putiac(IAC);
296 putiac(SB);
297 putiac(c);
298 putiac(0);
299
300 while (*str)
301 putiac(*str++);
302
303 putiac(IAC);
304 putiac(SE);
305}
306#endif
307
308#if ENABLE_FEATURE_TELNET_AUTOLOGIN
309static void putiac_subopt_autologin(void)
310{
311 int len = strlen(G.autologin) + 6; // (2 + 1 + 1 + strlen + 2)
312 const char *user = "USER";
313
314 if (G.iaclen + len > IACBUFSIZE)
315 iacflush();
316
317 putiac(IAC);
318 putiac(SB);
319 putiac(TELOPT_NEW_ENVIRON);
320 putiac(TELQUAL_IS);
321 putiac(NEW_ENV_VAR);
322
323 while (*user)
324 putiac(*user++);
325
326 putiac(NEW_ENV_VALUE);
327
328 while (*G.autologin)
329 putiac(*G.autologin++);
330
331 putiac(IAC);
332 putiac(SE);
333}
334#endif
335
336#if ENABLE_FEATURE_AUTOWIDTH
337static void putiac_naws(byte c, int x, int y)
338{
339 if (G.iaclen + 9 > IACBUFSIZE)
340 iacflush();
341
342 putiac(IAC);
343 putiac(SB);
344 putiac(c);
345
346 putiac((x >> 8) & 0xff);
347 putiac(x & 0xff);
348 putiac((y >> 8) & 0xff);
349 putiac(y & 0xff);
350
351 putiac(IAC);
352 putiac(SE);
353}
354#endif
355
356static char const escapecharis[] ALIGN1 = "\r\nEscape character is ";
357
358static void setConMode(void)
359{
360 if (G.telflags & UF_ECHO) {
361 if (G.charmode == CHM_TRY) {
362 G.charmode = CHM_ON;
363 printf("\r\nEntering character mode%s'^]'.\r\n", escapecharis);
364 rawmode();
365 }
366 } else {
367 if (G.charmode != CHM_OFF) {
368 G.charmode = CHM_OFF;
369 printf("\r\nEntering line mode%s'^C'.\r\n", escapecharis);
370 cookmode();
371 }
372 }
373}
374
375static void will_charmode(void)
376{
377 G.charmode = CHM_TRY;
378 G.telflags |= (UF_ECHO | UF_SGA);
379 setConMode();
380
381 putiac2(DO, TELOPT_ECHO);
382 putiac2(DO, TELOPT_SGA);
383 iacflush();
384}
385
386static void do_linemode(void)
387{
388 G.charmode = CHM_TRY;
389 G.telflags &= ~(UF_ECHO | UF_SGA);
390 setConMode();
391
392 putiac2(DONT, TELOPT_ECHO);
393 putiac2(DONT, TELOPT_SGA);
394 iacflush();
395}
396
397static void to_notsup(char c)
398{
399 if (G.telwish == WILL)
400 putiac2(DONT, c);
401 else if (G.telwish == DO)
402 putiac2(WONT, c);
403}
404
405static void to_echo(void)
406{
407 /* if server requests ECHO, don't agree */
408 if (G.telwish == DO) {
409 putiac2(WONT, TELOPT_ECHO);
410 return;
411 }
412 if (G.telwish == DONT)
413 return;
414
415 if (G.telflags & UF_ECHO) {
416 if (G.telwish == WILL)
417 return;
418 } else if (G.telwish == WONT)
419 return;
420
421 if (G.charmode != CHM_OFF)
422 G.telflags ^= UF_ECHO;
423
424 if (G.telflags & UF_ECHO)
425 putiac2(DO, TELOPT_ECHO);
426 else
427 putiac2(DONT, TELOPT_ECHO);
428
429 setConMode();
430 write_str(1, "\r\n"); /* sudden modec */
431}
432
433static void to_sga(void)
434{
435 /* daemon always sends will/wont, client do/dont */
436
437 if (G.telflags & UF_SGA) {
438 if (G.telwish == WILL)
439 return;
440 } else if (G.telwish == WONT)
441 return;
442
443 if ((G.telflags ^= UF_SGA) & UF_SGA) /* toggle */
444 putiac2(DO, TELOPT_SGA);
445 else
446 putiac2(DONT, TELOPT_SGA);
447}
448
449#if ENABLE_FEATURE_TELNET_TTYPE
450static void to_ttype(void)
451{
452 /* Tell server we will (or won't) do TTYPE */
453
454 if (G.ttype)
455 putiac2(WILL, TELOPT_TTYPE);
456 else
457 putiac2(WONT, TELOPT_TTYPE);
458}
459#endif
460
461#if ENABLE_FEATURE_TELNET_AUTOLOGIN
462static void to_new_environ(void)
463{
464 /* Tell server we will (or will not) do AUTOLOGIN */
465
466 if (G.autologin)
467 putiac2(WILL, TELOPT_NEW_ENVIRON);
468 else
469 putiac2(WONT, TELOPT_NEW_ENVIRON);
470}
471#endif
472
473#if ENABLE_FEATURE_AUTOWIDTH
474static void to_naws(void)
475{
476 /* Tell server we will do NAWS */
477 putiac2(WILL, TELOPT_NAWS);
478}
479#endif
480
481static void telopt(byte c)
482{
483 switch (c) {
484 case TELOPT_ECHO:
485 to_echo(); break;
486 case TELOPT_SGA:
487 to_sga(); break;
488#if ENABLE_FEATURE_TELNET_TTYPE
489 case TELOPT_TTYPE:
490 to_ttype(); break;
491#endif
492#if ENABLE_FEATURE_TELNET_AUTOLOGIN
493 case TELOPT_NEW_ENVIRON:
494 to_new_environ(); break;
495#endif
496#if ENABLE_FEATURE_AUTOWIDTH
497 case TELOPT_NAWS:
498 to_naws();
499 putiac_naws(c, G.win_width, G.win_height);
500 break;
501#endif
502 default:
503 to_notsup(c);
504 break;
505 }
506}
507
508/* subnegotiation -- ignore all (except TTYPE,NAWS) */
509static int subneg(byte c)
510{
511 switch (G.telstate) {
512 case TS_SUB1:
513 if (c == IAC)
514 G.telstate = TS_SUB2;
515#if ENABLE_FEATURE_TELNET_TTYPE
516 else
517 if (c == TELOPT_TTYPE)
518 putiac_subopt(TELOPT_TTYPE, G.ttype);
519#endif
520#if ENABLE_FEATURE_TELNET_AUTOLOGIN
521 else
522 if (c == TELOPT_NEW_ENVIRON)
523 putiac_subopt_autologin();
524#endif
525 break;
526 case TS_SUB2:
527 if (c == SE)
528 return TRUE;
529 G.telstate = TS_SUB1;
530 /* break; */
531 }
532 return FALSE;
533}
534
535static void fgotsig(int sig)
536{
537 G.gotsig = sig;
538}
539
540
541static void rawmode(void)
542{
543 if (G.do_termios)
544 tcsetattr(0, TCSADRAIN, &G.termios_raw);
545}
546
547static void cookmode(void)
548{
549 if (G.do_termios)
550 tcsetattr(0, TCSADRAIN, &G.termios_def);
551}
552
553int telnet_main(int argc, char** argv);
554int telnet_main(int argc, char** argv)
555{
556 char *host;
557 int port;
558 int len;
559#ifdef USE_POLL
560 struct pollfd ufds[2];
561#else
562 fd_set readfds;
563 int maxfd;
564#endif
565
566 INIT_G();
567
568#if ENABLE_FEATURE_AUTOWIDTH
569 get_terminal_width_height(0, &G.win_width, &G.win_height);
570#endif
571
572#if ENABLE_FEATURE_TELNET_TTYPE
573 G.ttype = getenv("TERM");
574#endif
575
576 if (tcgetattr(0, &G.termios_def) >= 0) {
577 G.do_termios = 1;
578 G.termios_raw = G.termios_def;
579 cfmakeraw(&G.termios_raw);
580 }
581
582 if (argc < 2)
583 bb_show_usage();
584
585#if ENABLE_FEATURE_TELNET_AUTOLOGIN
586 if (1 & getopt32(argv, "al:", &G.autologin))
587 G.autologin = getenv("USER");
588 argv += optind;
589#else
590 argv++;
591#endif
592 if (!*argv)
593 bb_show_usage();
594 host = *argv++;
595 port = bb_lookup_port(*argv ? *argv++ : "telnet", "tcp", 23);
596 if (*argv) /* extra params?? */
597 bb_show_usage();
598
599 G.netfd = create_and_connect_stream_or_die(host, port);
600
601 setsockopt(G.netfd, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
602
603 signal(SIGINT, fgotsig);
604
605#ifdef USE_POLL
606 ufds[0].fd = 0; ufds[1].fd = G.netfd;
607 ufds[0].events = ufds[1].events = POLLIN;
608#else
609 FD_ZERO(&readfds);
610 FD_SET(0, &readfds);
611 FD_SET(G.netfd, &readfds);
612 maxfd = G.netfd + 1;
613#endif
614
615 while (1) {
616#ifndef USE_POLL
617 fd_set rfds = readfds;
618
619 switch (select(maxfd, &rfds, NULL, NULL, NULL))
620#else
621 switch (poll(ufds, 2, -1))
622#endif
623 {
624 case 0:
625 /* timeout */
626 case -1:
627 /* error, ignore and/or log something, bay go to loop */
628 if (G.gotsig)
629 conescape();
630 else
631 sleep(1);
632 break;
633 default:
634
635#ifdef USE_POLL
636 if (ufds[0].revents) /* well, should check POLLIN, but ... */
637#else
638 if (FD_ISSET(0, &rfds))
639#endif
640 {
641 len = read(0, G.buf, DATABUFSIZE);
642 if (len <= 0)
643 doexit(0);
644 TRACE(0, ("Read con: %d\n", len));
645 handlenetoutput(len);
646 }
647
648#ifdef USE_POLL
649 if (ufds[1].revents) /* well, should check POLLIN, but ... */
650#else
651 if (FD_ISSET(G.netfd, &rfds))
652#endif
653 {
654 len = read(G.netfd, G.buf, DATABUFSIZE);
655 if (len <= 0) {
656 write_str(1, "Connection closed by foreign host\r\n");
657 doexit(1);
658 }
659 TRACE(0, ("Read netfd (%d): %d\n", G.netfd, len));
660 handlenetinput(len);
661 }
662 }
663 }
664}
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