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Eric Andersen28c70b32000-06-14 20:42:57 +00001/* vi: set sw=4 ts=4: */
Erik Andersenf7c49ef2000-02-22 17:17:45 +00002/*
Eric Andersen28c70b32000-06-14 20:42:57 +00003 * telnet implementation for busybox
Erik Andersenf7c49ef2000-02-22 17:17:45 +00004 *
Eric Andersen28c70b32000-06-14 20:42:57 +00005 * 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
Erik Andersenf7c49ef2000-02-22 17:17:45 +000010 *
Denys Vlasenko0ef64bd2010-08-16 20:14:46 +020011 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
Erik Andersenf7c49ef2000-02-22 17:17:45 +000012 *
Eric Andersen28c70b32000-06-14 20:42:57 +000013 * HISTORY
14 * Revision 3.1 1994/04/17 11:31:54 too
15 * initial revision
Eric Andersencb81e642003-07-14 21:21:08 +000016 * Modified 2000/06/13 for inclusion into BusyBox by Erik Andersen <andersen@codepoet.org>
Eric Andersen7e1273e2001-05-07 17:57:45 +000017 * Modified 2001/05/07 to add ability to pass TTYPE to remote host by Jim McQuillan
18 * <jam@ltsp.org>
Eric Andersen539ffc92004-02-22 12:25:47 +000019 * Modified 2004/02/11 to add ability to pass the USER variable to remote host
20 * by Fernando Silveira <swrh@gmx.net>
Erik Andersenf7c49ef2000-02-22 17:17:45 +000021 *
Erik Andersenf7c49ef2000-02-22 17:17:45 +000022 */
23
Pere Orga5bc8c002011-04-11 03:29:49 +020024//usage:#if ENABLE_FEATURE_TELNET_AUTOLOGIN
25//usage:#define telnet_trivial_usage
26//usage: "[-a] [-l USER] HOST [PORT]"
27//usage:#define telnet_full_usage "\n\n"
28//usage: "Connect to telnet server\n"
Pere Orga5bc8c002011-04-11 03:29:49 +020029//usage: "\n -a Automatic login with $USER variable"
30//usage: "\n -l USER Automatic login as USER"
31//usage:
32//usage:#else
33//usage:#define telnet_trivial_usage
34//usage: "HOST [PORT]"
35//usage:#define telnet_full_usage "\n\n"
36//usage: "Connect to telnet server"
37//usage:#endif
38
Eric Andersen28c70b32000-06-14 20:42:57 +000039#include <arpa/telnet.h>
Eric Andersen28c70b32000-06-14 20:42:57 +000040#include <netinet/in.h>
Denis Vlasenkob6adbf12007-05-26 19:00:18 +000041#include "libbb.h"
Erik Andersenf7c49ef2000-02-22 17:17:45 +000042
Denys Vlasenko14bd16a2011-07-08 08:49:40 +020043#ifdef __BIONIC__
44/* should be in arpa/telnet.h */
45# define IAC 255 /* interpret as command: */
46# define DONT 254 /* you are not to use option */
47# define DO 253 /* please, you use option */
48# define WONT 252 /* I won't use option */
49# define WILL 251 /* I will use option */
50# define SB 250 /* interpret as subnegotiation */
51# define SE 240 /* end sub negotiation */
52# define TELOPT_ECHO 1 /* echo */
53# define TELOPT_SGA 3 /* suppress go ahead */
54# define TELOPT_TTYPE 24 /* terminal type */
55# define TELOPT_NAWS 31 /* window size */
56#endif
57
Pavel Roskin616d13b2000-07-28 19:38:27 +000058#ifdef DOTRACE
Denys Vlasenko14bd16a2011-07-08 08:49:40 +020059# define TRACE(x, y) do { if (x) printf y; } while (0)
Eric Andersen28c70b32000-06-14 20:42:57 +000060#else
Denys Vlasenko14bd16a2011-07-08 08:49:40 +020061# define TRACE(x, y)
Eric Andersen28c70b32000-06-14 20:42:57 +000062#endif
63
Mark Whitley59ab0252001-01-23 22:30:04 +000064enum {
Denis Vlasenkof24cdf12007-03-19 14:47:09 +000065 DATABUFSIZE = 128,
66 IACBUFSIZE = 128,
67
Rob Landleybc68cd12006-03-10 19:22:06 +000068 CHM_TRY = 0,
69 CHM_ON = 1,
70 CHM_OFF = 2,
71
72 UF_ECHO = 0x01,
73 UF_SGA = 0x02,
74
Denys Vlasenko036dbb92010-10-29 02:12:22 +020075 TS_NORMAL = 0,
76 TS_COPY = 1,
Mark Whitley59ab0252001-01-23 22:30:04 +000077 TS_IAC = 2,
78 TS_OPT = 3,
79 TS_SUB1 = 4,
80 TS_SUB2 = 5,
Denys Vlasenko036dbb92010-10-29 02:12:22 +020081 TS_CR = 6,
Mark Whitley59ab0252001-01-23 22:30:04 +000082};
Eric Andersen28c70b32000-06-14 20:42:57 +000083
Eric Andersen28c70b32000-06-14 20:42:57 +000084typedef unsigned char byte;
85
Denis Vlasenko1101d1c2008-07-21 09:22:28 +000086enum { netfd = 3 };
87
Denis Vlasenkof24cdf12007-03-19 14:47:09 +000088struct globals {
Denis Vlasenko1101d1c2008-07-21 09:22:28 +000089 int iaclen; /* could even use byte, but it's a loss on x86 */
Eric Andersen28c70b32000-06-14 20:42:57 +000090 byte telstate; /* telnet negotiation state from network input */
91 byte telwish; /* DO, DONT, WILL, WONT */
92 byte charmode;
93 byte telflags;
Paul Foxf2ddc052005-07-20 19:55:19 +000094 byte do_termios;
Denis Vlasenkof24cdf12007-03-19 14:47:09 +000095#if ENABLE_FEATURE_TELNET_TTYPE
96 char *ttype;
97#endif
98#if ENABLE_FEATURE_TELNET_AUTOLOGIN
99 const char *autologin;
100#endif
101#if ENABLE_FEATURE_AUTOWIDTH
Denis Vlasenko55995022008-05-18 22:28:26 +0000102 unsigned win_width, win_height;
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000103#endif
104 /* same buffer used both for network and console read/write */
Denis Vlasenko54e3d1f2007-03-19 14:52:26 +0000105 char buf[DATABUFSIZE];
106 /* buffer to handle telnet negotiations */
Glenn L McGrath78b0e372001-06-26 02:06:08 +0000107 char iacbuf[IACBUFSIZE];
Eric Andersenc7bda1c2004-03-15 08:29:22 +0000108 struct termios termios_def;
109 struct termios termios_raw;
Denys Vlasenko98a4c7c2010-02-04 15:00:15 +0100110} FIX_ALIASING;
Denis Vlasenko4e5f82c2007-06-03 22:30:22 +0000111#define G (*(struct globals*)&bb_common_bufsiz1)
Denis Vlasenko74324c82007-06-04 10:16:52 +0000112#define INIT_G() do { \
Denys Vlasenko1b34d4f2009-09-30 02:39:57 +0200113 struct G_sizecheck { \
114 char G_sizecheck[sizeof(G) > COMMON_BUFSIZE ? -1 : 1]; \
115 }; \
Denis Vlasenko74324c82007-06-04 10:16:52 +0000116} while (0)
Eric Andersen28c70b32000-06-14 20:42:57 +0000117
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200118
Eric Andersencd8c4362001-11-10 11:22:46 +0000119static void rawmode(void);
120static void cookmode(void);
121static void do_linemode(void);
122static void will_charmode(void);
Eric Andersen28c70b32000-06-14 20:42:57 +0000123static void telopt(byte c);
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200124static void subneg(byte c);
Eric Andersen28c70b32000-06-14 20:42:57 +0000125
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000126static void iac_flush(void)
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000127{
Denys Vlasenkof76fd172013-05-12 02:13:24 +0200128 full_write(netfd, G.iacbuf, G.iaclen);
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000129 G.iaclen = 0;
130}
Eric Andersen7e1273e2001-05-07 17:57:45 +0000131
Denis Vlasenkoa60f84e2008-07-05 09:18:54 +0000132static void doexit(int ev) NORETURN;
Denis Vlasenko54e3d1f2007-03-19 14:52:26 +0000133static void doexit(int ev)
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000134{
Eric Andersen28c70b32000-06-14 20:42:57 +0000135 cookmode();
136 exit(ev);
Eric Andersenc7bda1c2004-03-15 08:29:22 +0000137}
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000138
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000139static void con_escape(void)
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000140{
Eric Andersen28c70b32000-06-14 20:42:57 +0000141 char b;
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000142
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000143 if (bb_got_signal) /* came from line mode... go raw */
Eric Andersen28c70b32000-06-14 20:42:57 +0000144 rawmode();
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000145
Denys Vlasenkof76fd172013-05-12 02:13:24 +0200146 full_write1_str("\r\nConsole escape. Commands are:\r\n\n"
Eric Andersen28c70b32000-06-14 20:42:57 +0000147 " l go to line mode\r\n"
148 " c go to character mode\r\n"
149 " z suspend telnet\r\n"
150 " e exit telnet\r\n");
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000151
Bernhard Reutner-Fischer5e25ddb2008-05-19 09:48:17 +0000152 if (read(STDIN_FILENO, &b, 1) <= 0)
Bernhard Reutner-Fischer636a1f82008-05-19 09:29:47 +0000153 doexit(EXIT_FAILURE);
Eric Andersen28c70b32000-06-14 20:42:57 +0000154
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000155 switch (b) {
Eric Andersen28c70b32000-06-14 20:42:57 +0000156 case 'l':
Denis Vlasenko08ea11a2008-09-11 19:51:11 +0000157 if (!bb_got_signal) {
Eric Andersen28c70b32000-06-14 20:42:57 +0000158 do_linemode();
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000159 goto ret;
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000160 }
Eric Andersen28c70b32000-06-14 20:42:57 +0000161 break;
162 case 'c':
Denis Vlasenko08ea11a2008-09-11 19:51:11 +0000163 if (bb_got_signal) {
Eric Andersen28c70b32000-06-14 20:42:57 +0000164 will_charmode();
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000165 goto ret;
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000166 }
Eric Andersen28c70b32000-06-14 20:42:57 +0000167 break;
168 case 'z':
169 cookmode();
170 kill(0, SIGTSTP);
171 rawmode();
172 break;
173 case 'e':
Bernhard Reutner-Fischer636a1f82008-05-19 09:29:47 +0000174 doexit(EXIT_SUCCESS);
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000175 }
Eric Andersen28c70b32000-06-14 20:42:57 +0000176
Denys Vlasenkof76fd172013-05-12 02:13:24 +0200177 full_write1_str("continuing...\r\n");
Eric Andersen28c70b32000-06-14 20:42:57 +0000178
Denis Vlasenko08ea11a2008-09-11 19:51:11 +0000179 if (bb_got_signal)
Eric Andersen28c70b32000-06-14 20:42:57 +0000180 cookmode();
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000181 ret:
Denis Vlasenko08ea11a2008-09-11 19:51:11 +0000182 bb_got_signal = 0;
Eric Andersen28c70b32000-06-14 20:42:57 +0000183}
Denis Vlasenko54e3d1f2007-03-19 14:52:26 +0000184
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000185static void handle_net_output(int len)
Eric Andersen28c70b32000-06-14 20:42:57 +0000186{
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200187 byte outbuf[2 * DATABUFSIZE];
Denys Vlasenko0ffd63c2012-09-17 11:54:35 +0200188 byte *dst = outbuf;
189 byte *src = (byte*)G.buf;
190 byte *end = src + len;
Eric Andersen28c70b32000-06-14 20:42:57 +0000191
Denys Vlasenko0ffd63c2012-09-17 11:54:35 +0200192 while (src < end) {
193 byte c = *src++;
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200194 if (c == 0x1d) {
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000195 con_escape();
Eric Andersen28c70b32000-06-14 20:42:57 +0000196 return;
197 }
Denys Vlasenko0ffd63c2012-09-17 11:54:35 +0200198 *dst = c;
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200199 if (c == IAC)
Denys Vlasenko0ffd63c2012-09-17 11:54:35 +0200200 *++dst = c; /* IAC -> IAC IAC */
201 else
202 if (c == '\r' || c == '\n') {
203 /* Enter key sends '\r' in raw mode and '\n' in cooked one.
204 *
205 * See RFC 1123 3.3.1 Telnet End-of-Line Convention.
Denys Vlasenkoaca464d2012-09-13 13:00:49 +0200206 * Using CR LF instead of other allowed possibilities
207 * like CR NUL - easier to talk to HTTP/SMTP servers.
208 */
Denys Vlasenko0ffd63c2012-09-17 11:54:35 +0200209 *dst = '\r'; /* Enter -> CR LF */
210 *++dst = '\n';
211 }
212 dst++;
Eric Andersen28c70b32000-06-14 20:42:57 +0000213 }
Denys Vlasenko0ffd63c2012-09-17 11:54:35 +0200214 if (dst - outbuf != 0)
215 full_write(netfd, outbuf, dst - outbuf);
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000216}
217
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000218static void handle_net_input(int len)
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000219{
Eric Andersen28c70b32000-06-14 20:42:57 +0000220 int i;
221 int cstart = 0;
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000222
Denis Vlasenko1bec1b92007-11-06 02:23:39 +0000223 for (i = 0; i < len; i++) {
Eric Andersen28c70b32000-06-14 20:42:57 +0000224 byte c = G.buf[i];
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000225
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200226 if (G.telstate == TS_NORMAL) { /* most typical state */
Denis Vlasenko1bec1b92007-11-06 02:23:39 +0000227 if (c == IAC) {
Eric Andersen28c70b32000-06-14 20:42:57 +0000228 cstart = i;
229 G.telstate = TS_IAC;
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000230 }
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200231 else if (c == '\r') {
232 cstart = i + 1;
233 G.telstate = TS_CR;
234 }
235 /* No IACs were seen so far, no need to copy
236 * bytes within G.buf: */
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000237 continue;
238 }
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200239
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000240 switch (G.telstate) {
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200241 case TS_CR:
242 /* Prev char was CR. If cur one is NUL, ignore it.
243 * See RFC 1123 section 3.3.1 for discussion of telnet EOL handling.
244 */
245 G.telstate = TS_COPY;
246 if (c == '\0')
247 break;
248 /* else: fall through - need to handle CR IAC ... properly */
249
250 case TS_COPY: /* Prev char was ordinary */
251 /* Similar to NORMAL, but in TS_COPY we need to copy bytes */
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000252 if (c == IAC)
253 G.telstate = TS_IAC;
254 else
255 G.buf[cstart++] = c;
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200256 if (c == '\r')
257 G.telstate = TS_CR;
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000258 break;
Eric Andersen28c70b32000-06-14 20:42:57 +0000259
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200260 case TS_IAC: /* Prev char was IAC */
261 if (c == IAC) { /* IAC IAC -> one IAC */
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000262 G.buf[cstart++] = c;
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200263 G.telstate = TS_COPY;
Denis Vlasenko1bec1b92007-11-06 02:23:39 +0000264 break;
Denis Vlasenko1bec1b92007-11-06 02:23:39 +0000265 }
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000266 /* else */
267 switch (c) {
268 case SB:
269 G.telstate = TS_SUB1;
270 break;
271 case DO:
272 case DONT:
273 case WILL:
274 case WONT:
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200275 G.telwish = c;
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000276 G.telstate = TS_OPT;
277 break;
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200278 /* DATA MARK must be added later */
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000279 default:
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200280 G.telstate = TS_COPY;
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000281 }
282 break;
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200283
284 case TS_OPT: /* Prev chars were IAC WILL/WONT/DO/DONT */
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000285 telopt(c);
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200286 G.telstate = TS_COPY;
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000287 break;
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200288
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000289 case TS_SUB1: /* Subnegotiation */
290 case TS_SUB2: /* Subnegotiation */
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200291 subneg(c); /* can change G.telstate */
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000292 break;
293 }
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000294 }
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200295
296 if (G.telstate != TS_NORMAL) {
297 /* We had some IACs, or CR */
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000298 if (G.iaclen)
299 iac_flush();
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200300 if (G.telstate == TS_COPY) /* we aren't in the middle of IAC */
301 G.telstate = TS_NORMAL;
Glenn L McGrath78b0e372001-06-26 02:06:08 +0000302 len = cstart;
Eric Andersen28c70b32000-06-14 20:42:57 +0000303 }
304
Glenn L McGrath78b0e372001-06-26 02:06:08 +0000305 if (len)
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200306 full_write(STDOUT_FILENO, G.buf, len);
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000307}
308
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000309static void put_iac(int c)
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000310{
Eric Andersen28c70b32000-06-14 20:42:57 +0000311 G.iacbuf[G.iaclen++] = c;
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000312}
313
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000314static void put_iac2(byte wwdd, byte c)
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000315{
Eric Andersen28c70b32000-06-14 20:42:57 +0000316 if (G.iaclen + 3 > IACBUFSIZE)
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000317 iac_flush();
Eric Andersen28c70b32000-06-14 20:42:57 +0000318
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000319 put_iac(IAC);
320 put_iac(wwdd);
321 put_iac(c);
Erik Andersenf7c49ef2000-02-22 17:17:45 +0000322}
323
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000324#if ENABLE_FEATURE_TELNET_TTYPE
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000325static void put_iac_subopt(byte c, char *str)
Eric Andersen7e1273e2001-05-07 17:57:45 +0000326{
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000327 int len = strlen(str) + 6; // ( 2 + 1 + 1 + strlen + 2 )
Eric Andersen7e1273e2001-05-07 17:57:45 +0000328
329 if (G.iaclen + len > IACBUFSIZE)
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000330 iac_flush();
Eric Andersen7e1273e2001-05-07 17:57:45 +0000331
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000332 put_iac(IAC);
333 put_iac(SB);
334 put_iac(c);
335 put_iac(0);
Eric Andersen7e1273e2001-05-07 17:57:45 +0000336
Denis Vlasenkobf0a2012006-12-26 10:42:51 +0000337 while (*str)
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000338 put_iac(*str++);
Eric Andersen7e1273e2001-05-07 17:57:45 +0000339
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000340 put_iac(IAC);
341 put_iac(SE);
Eric Andersen7e1273e2001-05-07 17:57:45 +0000342}
343#endif
344
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000345#if ENABLE_FEATURE_TELNET_AUTOLOGIN
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000346static void put_iac_subopt_autologin(void)
Eric Andersen539ffc92004-02-22 12:25:47 +0000347{
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000348 int len = strlen(G.autologin) + 6; // (2 + 1 + 1 + strlen + 2)
Denys Vlasenko25b10d92010-04-27 08:54:24 +0200349 const char *p = "USER";
Eric Andersen539ffc92004-02-22 12:25:47 +0000350
351 if (G.iaclen + len > IACBUFSIZE)
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000352 iac_flush();
Eric Andersen539ffc92004-02-22 12:25:47 +0000353
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000354 put_iac(IAC);
355 put_iac(SB);
356 put_iac(TELOPT_NEW_ENVIRON);
357 put_iac(TELQUAL_IS);
358 put_iac(NEW_ENV_VAR);
Eric Andersen539ffc92004-02-22 12:25:47 +0000359
Denys Vlasenko25b10d92010-04-27 08:54:24 +0200360 while (*p)
361 put_iac(*p++);
Eric Andersen539ffc92004-02-22 12:25:47 +0000362
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000363 put_iac(NEW_ENV_VALUE);
Eric Andersen539ffc92004-02-22 12:25:47 +0000364
Denys Vlasenko25b10d92010-04-27 08:54:24 +0200365 p = G.autologin;
366 while (*p)
367 put_iac(*p++);
Eric Andersen539ffc92004-02-22 12:25:47 +0000368
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000369 put_iac(IAC);
370 put_iac(SE);
Eric Andersen539ffc92004-02-22 12:25:47 +0000371}
372#endif
373
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000374#if ENABLE_FEATURE_AUTOWIDTH
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000375static void put_iac_naws(byte c, int x, int y)
Eric Andersen0e28e1f2002-04-26 07:20:47 +0000376{
377 if (G.iaclen + 9 > IACBUFSIZE)
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000378 iac_flush();
Eric Andersen0e28e1f2002-04-26 07:20:47 +0000379
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000380 put_iac(IAC);
381 put_iac(SB);
382 put_iac(c);
Eric Andersen0e28e1f2002-04-26 07:20:47 +0000383
Denys Vlasenkof76fd172013-05-12 02:13:24 +0200384 /* "... & 0xff" implicitly done below */
385 put_iac(x >> 8);
386 put_iac(x);
387 put_iac(y >> 8);
388 put_iac(y);
Eric Andersen0e28e1f2002-04-26 07:20:47 +0000389
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000390 put_iac(IAC);
391 put_iac(SE);
Eric Andersen0e28e1f2002-04-26 07:20:47 +0000392}
393#endif
394
Eric Andersencd8c4362001-11-10 11:22:46 +0000395static void setConMode(void)
Eric Andersen28c70b32000-06-14 20:42:57 +0000396{
Denis Vlasenko54e3d1f2007-03-19 14:52:26 +0000397 if (G.telflags & UF_ECHO) {
Eric Andersen28c70b32000-06-14 20:42:57 +0000398 if (G.charmode == CHM_TRY) {
399 G.charmode = CHM_ON;
Denys Vlasenko57f07bf2012-09-17 11:53:09 +0200400 printf("\r\nEntering %s mode"
401 "\r\nEscape character is '^%c'.\r\n", "character", ']');
Eric Andersen28c70b32000-06-14 20:42:57 +0000402 rawmode();
403 }
Denis Vlasenko54e3d1f2007-03-19 14:52:26 +0000404 } else {
Eric Andersen28c70b32000-06-14 20:42:57 +0000405 if (G.charmode != CHM_OFF) {
406 G.charmode = CHM_OFF;
Denys Vlasenko57f07bf2012-09-17 11:53:09 +0200407 printf("\r\nEntering %s mode"
408 "\r\nEscape character is '^%c'.\r\n", "line", 'C');
Eric Andersen28c70b32000-06-14 20:42:57 +0000409 cookmode();
410 }
411 }
412}
413
Eric Andersencd8c4362001-11-10 11:22:46 +0000414static void will_charmode(void)
Eric Andersen28c70b32000-06-14 20:42:57 +0000415{
416 G.charmode = CHM_TRY;
417 G.telflags |= (UF_ECHO | UF_SGA);
418 setConMode();
Eric Andersenc7bda1c2004-03-15 08:29:22 +0000419
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000420 put_iac2(DO, TELOPT_ECHO);
421 put_iac2(DO, TELOPT_SGA);
422 iac_flush();
Eric Andersen28c70b32000-06-14 20:42:57 +0000423}
424
Eric Andersencd8c4362001-11-10 11:22:46 +0000425static void do_linemode(void)
Eric Andersen28c70b32000-06-14 20:42:57 +0000426{
427 G.charmode = CHM_TRY;
428 G.telflags &= ~(UF_ECHO | UF_SGA);
429 setConMode();
430
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000431 put_iac2(DONT, TELOPT_ECHO);
432 put_iac2(DONT, TELOPT_SGA);
433 iac_flush();
Eric Andersen28c70b32000-06-14 20:42:57 +0000434}
435
Rob Landley88621d72006-08-29 19:41:06 +0000436static void to_notsup(char c)
Eric Andersen28c70b32000-06-14 20:42:57 +0000437{
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000438 if (G.telwish == WILL)
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000439 put_iac2(DONT, c);
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000440 else if (G.telwish == DO)
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000441 put_iac2(WONT, c);
Eric Andersen28c70b32000-06-14 20:42:57 +0000442}
443
Rob Landley88621d72006-08-29 19:41:06 +0000444static void to_echo(void)
Eric Andersen28c70b32000-06-14 20:42:57 +0000445{
446 /* if server requests ECHO, don't agree */
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000447 if (G.telwish == DO) {
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000448 put_iac2(WONT, TELOPT_ECHO);
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000449 return;
450 }
451 if (G.telwish == DONT)
452 return;
Eric Andersenc7bda1c2004-03-15 08:29:22 +0000453
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000454 if (G.telflags & UF_ECHO) {
Eric Andersen28c70b32000-06-14 20:42:57 +0000455 if (G.telwish == WILL)
456 return;
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000457 } else if (G.telwish == WONT)
458 return;
Eric Andersen28c70b32000-06-14 20:42:57 +0000459
460 if (G.charmode != CHM_OFF)
461 G.telflags ^= UF_ECHO;
462
463 if (G.telflags & UF_ECHO)
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000464 put_iac2(DO, TELOPT_ECHO);
Eric Andersen28c70b32000-06-14 20:42:57 +0000465 else
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000466 put_iac2(DONT, TELOPT_ECHO);
Eric Andersen28c70b32000-06-14 20:42:57 +0000467
468 setConMode();
Denys Vlasenko729ecb82010-06-07 14:14:26 +0200469 full_write1_str("\r\n"); /* sudden modec */
Eric Andersen28c70b32000-06-14 20:42:57 +0000470}
471
Rob Landley88621d72006-08-29 19:41:06 +0000472static void to_sga(void)
Eric Andersen28c70b32000-06-14 20:42:57 +0000473{
474 /* daemon always sends will/wont, client do/dont */
475
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000476 if (G.telflags & UF_SGA) {
Eric Andersen28c70b32000-06-14 20:42:57 +0000477 if (G.telwish == WILL)
478 return;
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000479 } else if (G.telwish == WONT)
480 return;
Eric Andersenc7bda1c2004-03-15 08:29:22 +0000481
Denis Vlasenko1bec1b92007-11-06 02:23:39 +0000482 G.telflags ^= UF_SGA; /* toggle */
483 if (G.telflags & UF_SGA)
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000484 put_iac2(DO, TELOPT_SGA);
Eric Andersen28c70b32000-06-14 20:42:57 +0000485 else
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000486 put_iac2(DONT, TELOPT_SGA);
Eric Andersen28c70b32000-06-14 20:42:57 +0000487}
488
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000489#if ENABLE_FEATURE_TELNET_TTYPE
Rob Landley88621d72006-08-29 19:41:06 +0000490static void to_ttype(void)
Eric Andersen7e1273e2001-05-07 17:57:45 +0000491{
492 /* Tell server we will (or won't) do TTYPE */
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000493 if (G.ttype)
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000494 put_iac2(WILL, TELOPT_TTYPE);
Eric Andersen7e1273e2001-05-07 17:57:45 +0000495 else
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000496 put_iac2(WONT, TELOPT_TTYPE);
Eric Andersen7e1273e2001-05-07 17:57:45 +0000497}
498#endif
499
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000500#if ENABLE_FEATURE_TELNET_AUTOLOGIN
Rob Landley88621d72006-08-29 19:41:06 +0000501static void to_new_environ(void)
Eric Andersen539ffc92004-02-22 12:25:47 +0000502{
503 /* Tell server we will (or will not) do AUTOLOGIN */
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000504 if (G.autologin)
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000505 put_iac2(WILL, TELOPT_NEW_ENVIRON);
Eric Andersen539ffc92004-02-22 12:25:47 +0000506 else
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000507 put_iac2(WONT, TELOPT_NEW_ENVIRON);
Eric Andersen539ffc92004-02-22 12:25:47 +0000508}
509#endif
510
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000511#if ENABLE_FEATURE_AUTOWIDTH
Rob Landley88621d72006-08-29 19:41:06 +0000512static void to_naws(void)
Eric Andersenc7bda1c2004-03-15 08:29:22 +0000513{
Eric Andersen0e28e1f2002-04-26 07:20:47 +0000514 /* Tell server we will do NAWS */
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000515 put_iac2(WILL, TELOPT_NAWS);
Eric Andersenc7bda1c2004-03-15 08:29:22 +0000516}
Eric Andersen0e28e1f2002-04-26 07:20:47 +0000517#endif
518
Eric Andersen28c70b32000-06-14 20:42:57 +0000519static void telopt(byte c)
520{
Denis Vlasenkobaca1752007-03-11 13:43:10 +0000521 switch (c) {
522 case TELOPT_ECHO:
523 to_echo(); break;
524 case TELOPT_SGA:
525 to_sga(); break;
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000526#if ENABLE_FEATURE_TELNET_TTYPE
Denis Vlasenkobaca1752007-03-11 13:43:10 +0000527 case TELOPT_TTYPE:
528 to_ttype(); break;
Eric Andersen7e1273e2001-05-07 17:57:45 +0000529#endif
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000530#if ENABLE_FEATURE_TELNET_AUTOLOGIN
Denis Vlasenkobaca1752007-03-11 13:43:10 +0000531 case TELOPT_NEW_ENVIRON:
532 to_new_environ(); break;
Eric Andersen539ffc92004-02-22 12:25:47 +0000533#endif
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000534#if ENABLE_FEATURE_AUTOWIDTH
Denis Vlasenkobaca1752007-03-11 13:43:10 +0000535 case TELOPT_NAWS:
536 to_naws();
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000537 put_iac_naws(c, G.win_width, G.win_height);
Denis Vlasenkobaca1752007-03-11 13:43:10 +0000538 break;
Eric Andersen0e28e1f2002-04-26 07:20:47 +0000539#endif
Denis Vlasenkobaca1752007-03-11 13:43:10 +0000540 default:
541 to_notsup(c);
542 break;
Eric Andersen28c70b32000-06-14 20:42:57 +0000543 }
544}
545
Eric Andersen0e28e1f2002-04-26 07:20:47 +0000546/* subnegotiation -- ignore all (except TTYPE,NAWS) */
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200547static void subneg(byte c)
Eric Andersen28c70b32000-06-14 20:42:57 +0000548{
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000549 switch (G.telstate) {
Eric Andersen28c70b32000-06-14 20:42:57 +0000550 case TS_SUB1:
551 if (c == IAC)
552 G.telstate = TS_SUB2;
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000553#if ENABLE_FEATURE_TELNET_TTYPE
Eric Andersen7e1273e2001-05-07 17:57:45 +0000554 else
Denys Vlasenko25b10d92010-04-27 08:54:24 +0200555 if (c == TELOPT_TTYPE && G.ttype)
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000556 put_iac_subopt(TELOPT_TTYPE, G.ttype);
Eric Andersen7e1273e2001-05-07 17:57:45 +0000557#endif
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000558#if ENABLE_FEATURE_TELNET_AUTOLOGIN
Eric Andersen539ffc92004-02-22 12:25:47 +0000559 else
Denys Vlasenko25b10d92010-04-27 08:54:24 +0200560 if (c == TELOPT_NEW_ENVIRON && G.autologin)
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000561 put_iac_subopt_autologin();
Eric Andersen539ffc92004-02-22 12:25:47 +0000562#endif
Eric Andersen28c70b32000-06-14 20:42:57 +0000563 break;
564 case TS_SUB2:
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200565 if (c == SE) {
566 G.telstate = TS_COPY;
567 return;
568 }
Eric Andersen28c70b32000-06-14 20:42:57 +0000569 G.telstate = TS_SUB1;
Denys Vlasenko036dbb92010-10-29 02:12:22 +0200570 break;
Eric Andersen28c70b32000-06-14 20:42:57 +0000571 }
Eric Andersen28c70b32000-06-14 20:42:57 +0000572}
573
Eric Andersencd8c4362001-11-10 11:22:46 +0000574static void rawmode(void)
Eric Andersen28c70b32000-06-14 20:42:57 +0000575{
Denis Vlasenko54e3d1f2007-03-19 14:52:26 +0000576 if (G.do_termios)
577 tcsetattr(0, TCSADRAIN, &G.termios_raw);
Eric Andersenc7bda1c2004-03-15 08:29:22 +0000578}
Eric Andersen28c70b32000-06-14 20:42:57 +0000579
Eric Andersencd8c4362001-11-10 11:22:46 +0000580static void cookmode(void)
Eric Andersen28c70b32000-06-14 20:42:57 +0000581{
Denis Vlasenko54e3d1f2007-03-19 14:52:26 +0000582 if (G.do_termios)
583 tcsetattr(0, TCSADRAIN, &G.termios_def);
Eric Andersen28c70b32000-06-14 20:42:57 +0000584}
585
Denis Vlasenko9b49a5e2007-10-11 10:05:36 +0000586int telnet_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
Denis Vlasenko1101d1c2008-07-21 09:22:28 +0000587int telnet_main(int argc UNUSED_PARAM, char **argv)
Eric Andersen28c70b32000-06-14 20:42:57 +0000588{
Denis Vlasenko9de420c2007-01-10 09:28:01 +0000589 char *host;
590 int port;
Glenn L McGrath78b0e372001-06-26 02:06:08 +0000591 int len;
Eric Andersen28c70b32000-06-14 20:42:57 +0000592 struct pollfd ufds[2];
Eric Andersen28c70b32000-06-14 20:42:57 +0000593
Denis Vlasenko74324c82007-06-04 10:16:52 +0000594 INIT_G();
Eric Andersen28c70b32000-06-14 20:42:57 +0000595
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000596#if ENABLE_FEATURE_AUTOWIDTH
597 get_terminal_width_height(0, &G.win_width, &G.win_height);
598#endif
599
600#if ENABLE_FEATURE_TELNET_TTYPE
601 G.ttype = getenv("TERM");
602#endif
603
Paul Foxf2ddc052005-07-20 19:55:19 +0000604 if (tcgetattr(0, &G.termios_def) >= 0) {
605 G.do_termios = 1;
Paul Foxf2ddc052005-07-20 19:55:19 +0000606 G.termios_raw = G.termios_def;
607 cfmakeraw(&G.termios_raw);
608 }
Eric Andersenc7bda1c2004-03-15 08:29:22 +0000609
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000610#if ENABLE_FEATURE_TELNET_AUTOLOGIN
Denis Vlasenkofe7cd642007-08-18 15:32:12 +0000611 if (1 & getopt32(argv, "al:", &G.autologin))
Denis Vlasenkof24cdf12007-03-19 14:47:09 +0000612 G.autologin = getenv("USER");
Denis Vlasenko6536a9b2007-01-12 10:35:23 +0000613 argv += optind;
Eric Andersen539ffc92004-02-22 12:25:47 +0000614#else
Denis Vlasenko6536a9b2007-01-12 10:35:23 +0000615 argv++;
Eric Andersen539ffc92004-02-22 12:25:47 +0000616#endif
Denis Vlasenko6536a9b2007-01-12 10:35:23 +0000617 if (!*argv)
618 bb_show_usage();
619 host = *argv++;
620 port = bb_lookup_port(*argv ? *argv++ : "telnet", "tcp", 23);
621 if (*argv) /* extra params?? */
622 bb_show_usage();
623
Denis Vlasenko1101d1c2008-07-21 09:22:28 +0000624 xmove_fd(create_and_connect_stream_or_die(host, port), netfd);
Eric Andersen28c70b32000-06-14 20:42:57 +0000625
Denis Vlasenko1101d1c2008-07-21 09:22:28 +0000626 setsockopt(netfd, SOL_SOCKET, SO_KEEPALIVE, &const_int_1, sizeof(const_int_1));
Eric Andersen28c70b32000-06-14 20:42:57 +0000627
Denis Vlasenko08ea11a2008-09-11 19:51:11 +0000628 signal(SIGINT, record_signo);
Eric Andersen28c70b32000-06-14 20:42:57 +0000629
Denys Vlasenkoec074202010-10-29 02:33:38 +0200630 ufds[0].fd = STDIN_FILENO;
631 ufds[0].events = POLLIN;
632 ufds[1].fd = netfd;
633 ufds[1].events = POLLIN;
Eric Andersenc7bda1c2004-03-15 08:29:22 +0000634
Denis Vlasenko9de420c2007-01-10 09:28:01 +0000635 while (1) {
Denys Vlasenkoec074202010-10-29 02:33:38 +0200636 if (poll(ufds, 2, -1) < 0) {
Eric Andersen28c70b32000-06-14 20:42:57 +0000637 /* error, ignore and/or log something, bay go to loop */
Denis Vlasenko08ea11a2008-09-11 19:51:11 +0000638 if (bb_got_signal)
Denis Vlasenko9f2f8082008-11-11 02:56:39 +0000639 con_escape();
Eric Andersen28c70b32000-06-14 20:42:57 +0000640 else
641 sleep(1);
Denys Vlasenkoec074202010-10-29 02:33:38 +0200642 continue;
643 }
Eric Andersen28c70b32000-06-14 20:42:57 +0000644
Denys Vlasenkoec074202010-10-29 02:33:38 +0200645// FIXME: reads can block. Need full bidirectional buffering.
Eric Andersen28c70b32000-06-14 20:42:57 +0000646
Denys Vlasenkoec074202010-10-29 02:33:38 +0200647 if (ufds[0].revents) {
648 len = safe_read(STDIN_FILENO, G.buf, DATABUFSIZE);
649 if (len <= 0)
650 doexit(EXIT_SUCCESS);
651 TRACE(0, ("Read con: %d\n", len));
652 handle_net_output(len);
653 }
654
655 if (ufds[1].revents) {
656 len = safe_read(netfd, G.buf, DATABUFSIZE);
657 if (len <= 0) {
658 full_write1_str("Connection closed by foreign host\r\n");
659 doexit(EXIT_FAILURE);
Eric Andersen28c70b32000-06-14 20:42:57 +0000660 }
Denys Vlasenkoec074202010-10-29 02:33:38 +0200661 TRACE(0, ("Read netfd (%d): %d\n", netfd, len));
662 handle_net_input(len);
Eric Andersen28c70b32000-06-14 20:42:57 +0000663 }
Denis Vlasenko1101d1c2008-07-21 09:22:28 +0000664 } /* while (1) */
Eric Andersen28c70b32000-06-14 20:42:57 +0000665}