14 static Socket s = NULL;
16 #define IAC 255 /* interpret as command: */
17 #define DONT 254 /* you are not to use option */
18 #define DO 253 /* please, you use option */
19 #define WONT 252 /* I won't use option */
20 #define WILL 251 /* I will use option */
21 #define SB 250 /* interpret as subnegotiation */
22 #define SE 240 /* end sub negotiation */
24 #define GA 249 /* you may reverse the line */
25 #define EL 248 /* erase the current line */
26 #define EC 247 /* erase the current character */
27 #define AYT 246 /* are you there */
28 #define AO 245 /* abort output--but let prog finish */
29 #define IP 244 /* interrupt process--permanently */
30 #define BREAK 243 /* break */
31 #define DM 242 /* data mark--for connect. cleaning */
32 #define NOP 241 /* nop */
33 #define EOR 239 /* end of record (transparent mode) */
34 #define ABORT 238 /* Abort process */
35 #define SUSP 237 /* Suspend process */
36 #define xEOF 236 /* End of file: EOF is already used... */
38 #define TELOPT_BINARY 0 /* 8-bit data path */
39 #define TELOPT_ECHO 1 /* echo */
40 #define TELOPT_RCP 2 /* prepare to reconnect */
41 #define TELOPT_SGA 3 /* suppress go ahead */
42 #define TELOPT_NAMS 4 /* approximate message size */
43 #define TELOPT_STATUS 5 /* give status */
44 #define TELOPT_TM 6 /* timing mark */
45 #define TELOPT_RCTE 7 /* remote controlled transmission and echo */
46 #define TELOPT_NAOL 8 /* negotiate about output line width */
47 #define TELOPT_NAOP 9 /* negotiate about output page size */
48 #define TELOPT_NAOCRD 10 /* negotiate about CR disposition */
49 #define TELOPT_NAOHTS 11 /* negotiate about horizontal tabstops */
50 #define TELOPT_NAOHTD 12 /* negotiate about horizontal tab disposition */
51 #define TELOPT_NAOFFD 13 /* negotiate about formfeed disposition */
52 #define TELOPT_NAOVTS 14 /* negotiate about vertical tab stops */
53 #define TELOPT_NAOVTD 15 /* negotiate about vertical tab disposition */
54 #define TELOPT_NAOLFD 16 /* negotiate about output LF disposition */
55 #define TELOPT_XASCII 17 /* extended ascic character set */
56 #define TELOPT_LOGOUT 18 /* force logout */
57 #define TELOPT_BM 19 /* byte macro */
58 #define TELOPT_DET 20 /* data entry terminal */
59 #define TELOPT_SUPDUP 21 /* supdup protocol */
60 #define TELOPT_SUPDUPOUTPUT 22 /* supdup output */
61 #define TELOPT_SNDLOC 23 /* send location */
62 #define TELOPT_TTYPE 24 /* terminal type */
63 #define TELOPT_EOR 25 /* end or record */
64 #define TELOPT_TUID 26 /* TACACS user identification */
65 #define TELOPT_OUTMRK 27 /* output marking */
66 #define TELOPT_TTYLOC 28 /* terminal location number */
67 #define TELOPT_3270REGIME 29 /* 3270 regime */
68 #define TELOPT_X3PAD 30 /* X.3 PAD */
69 #define TELOPT_NAWS 31 /* window size */
70 #define TELOPT_TSPEED 32 /* terminal speed */
71 #define TELOPT_LFLOW 33 /* remote flow control */
72 #define TELOPT_LINEMODE 34 /* Linemode option */
73 #define TELOPT_XDISPLOC 35 /* X Display Location */
74 #define TELOPT_OLD_ENVIRON 36 /* Old - Environment variables */
75 #define TELOPT_AUTHENTICATION 37 /* Authenticate */
76 #define TELOPT_ENCRYPT 38 /* Encryption option */
77 #define TELOPT_NEW_ENVIRON 39 /* New - Environment variables */
78 #define TELOPT_EXOPL 255 /* extended-options-list */
80 #define TELQUAL_IS 0 /* option is... */
81 #define TELQUAL_SEND 1 /* send option */
82 #define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
92 #define iswritable(x) ( (x) != IAC && (x) != CR )
94 static char *telopt(int opt)
96 #define i(x) if (opt == TELOPT_ ## x) return #x;
141 static void telnet_size(void);
144 int send; /* what we initially send */
145 int nsend; /* -ve send if requested to stop it */
146 int ack, nak; /* +ve and -ve acknowledgements */
147 int option; /* the option code */
149 REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE
153 static struct Opt o_naws =
154 { WILL, WONT, DO, DONT, TELOPT_NAWS, REQUESTED };
155 static struct Opt o_tspeed =
156 { WILL, WONT, DO, DONT, TELOPT_TSPEED, REQUESTED };
157 static struct Opt o_ttype =
158 { WILL, WONT, DO, DONT, TELOPT_TTYPE, REQUESTED };
159 static struct Opt o_oenv = { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON,
162 static struct Opt o_nenv = { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON,
165 static struct Opt o_echo =
166 { DO, DONT, WILL, WONT, TELOPT_ECHO, REQUESTED };
167 static struct Opt o_we_sga =
168 { WILL, WONT, DO, DONT, TELOPT_SGA, REQUESTED };
169 static struct Opt o_they_sga =
170 { DO, DONT, WILL, WONT, TELOPT_SGA, REQUESTED };
172 static struct Opt *opts[] = {
173 &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,
174 &o_we_sga, &o_they_sga, NULL
177 #define TELNET_MAX_BACKLOG 4096
179 static int echoing = TRUE, editing = TRUE;
180 static int activated = FALSE;
181 static int telnet_bufsize;
183 static int sb_opt, sb_len;
184 static char *sb_buf = NULL;
185 static int sb_size = 0;
186 #define SB_DELTA 1024
188 static void c_write1(int c)
192 backlog = from_backend(0, &cc, 1);
193 sk_set_frozen(s, backlog > TELNET_MAX_BACKLOG);
196 static void log_option(char *sender, int cmd, int option)
199 sprintf(buf, "%s:\t%s %s", sender,
200 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
201 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<??>"),
206 static void send_opt(int cmd, int option)
213 telnet_bufsize = sk_write(s, b, 3);
214 log_option("client", cmd, option);
217 static void deactivate_option(struct Opt *o)
219 if (o->state == REQUESTED || o->state == ACTIVE)
220 send_opt(o->nsend, o->option);
221 o->state = REALLY_INACTIVE;
225 * Generate side effects of enabling or disabling an option.
227 static void option_side_effects(struct Opt *o, int enabled)
229 if (o->option == TELOPT_ECHO && o->send == DO)
231 else if (o->option == TELOPT_SGA && o->send == DO)
233 ldisc_send(NULL, 0); /* cause ldisc to notice the change */
235 /* Ensure we get the minimum options */
237 if (o_echo.state == INACTIVE) {
238 o_echo.state = REQUESTED;
239 send_opt(o_echo.send, o_echo.option);
241 if (o_we_sga.state == INACTIVE) {
242 o_we_sga.state = REQUESTED;
243 send_opt(o_we_sga.send, o_we_sga.option);
245 if (o_they_sga.state == INACTIVE) {
246 o_they_sga.state = REQUESTED;
247 send_opt(o_they_sga.send, o_they_sga.option);
253 static void activate_option(struct Opt *o)
255 if (o->send == WILL && o->option == TELOPT_NAWS)
257 if (o->send == WILL &&
258 (o->option == TELOPT_NEW_ENVIRON ||
259 o->option == TELOPT_OLD_ENVIRON)) {
261 * We may only have one kind of ENVIRON going at a time.
262 * This is a hack, but who cares.
264 deactivate_option(o->option ==
265 TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
267 option_side_effects(o, 1);
270 static void refused_option(struct Opt *o)
272 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
273 o_oenv.state == INACTIVE) {
274 send_opt(WILL, TELOPT_OLD_ENVIRON);
275 o_oenv.state = REQUESTED;
277 option_side_effects(o, 0);
280 static void proc_rec_opt(int cmd, int option)
284 log_option("server", cmd, option);
285 for (o = opts; *o; o++) {
286 if ((*o)->option == option && (*o)->ack == cmd) {
287 switch ((*o)->state) {
289 (*o)->state = ACTIVE;
295 (*o)->state = ACTIVE;
296 send_opt((*o)->send, option);
299 case REALLY_INACTIVE:
300 send_opt((*o)->nsend, option);
304 } else if ((*o)->option == option && (*o)->nak == cmd) {
305 switch ((*o)->state) {
307 (*o)->state = INACTIVE;
311 (*o)->state = INACTIVE;
312 send_opt((*o)->nsend, option);
313 option_side_effects(*o, 0);
316 case REALLY_INACTIVE:
323 * If we reach here, the option was one we weren't prepared to
324 * cope with. So send a negative ack.
326 send_opt((cmd == WILL ? DONT : WONT), option);
329 static void process_subneg(void)
331 unsigned char b[2048], *p, *q;
337 if (sb_len == 1 && sb_buf[0] == TELQUAL_SEND) {
338 char logbuf[sizeof(cfg.termspeed) + 80];
341 b[2] = TELOPT_TSPEED;
343 strcpy(b + 4, cfg.termspeed);
344 n = 4 + strlen(cfg.termspeed);
347 telnet_bufsize = sk_write(s, b, n + 2);
348 logevent("server:\tSB TSPEED SEND");
349 sprintf(logbuf, "client:\tSB TSPEED IS %s", cfg.termspeed);
352 logevent("server:\tSB TSPEED <something weird>");
355 if (sb_len == 1 && sb_buf[0] == TELQUAL_SEND) {
356 char logbuf[sizeof(cfg.termtype) + 80];
361 for (n = 0; cfg.termtype[n]; n++)
362 b[n + 4] = (cfg.termtype[n] >= 'a'
363 && cfg.termtype[n] <=
364 'z' ? cfg.termtype[n] + 'A' -
365 'a' : cfg.termtype[n]);
368 telnet_bufsize = sk_write(s, b, n + 6);
370 logevent("server:\tSB TTYPE SEND");
371 sprintf(logbuf, "client:\tSB TTYPE IS %s", b + 4);
374 logevent("server:\tSB TTYPE <something weird>\r\n");
376 case TELOPT_OLD_ENVIRON:
377 case TELOPT_NEW_ENVIRON:
380 if (p < q && *p == TELQUAL_SEND) {
383 sprintf(logbuf, "server:\tSB %s SEND", telopt(sb_opt));
385 if (sb_opt == TELOPT_OLD_ENVIRON) {
386 if (cfg.rfc_environ) {
394 * Try to guess the sense of VAR and VALUE.
400 } else if (*p == BSD_VAR) {
408 * With NEW_ENVIRON, the sense of VAR and VALUE
422 while (*e && *e != '\t')
444 telnet_bufsize = sk_write(s, b, n);
445 sprintf(logbuf, "client:\tSB %s IS %s", telopt(sb_opt),
446 n == 6 ? "<nothing>" : "<stuff>");
454 TOPLEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
455 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
456 } telnet_state = TOPLEVEL;
458 static void do_telnet_read(char *buf, int len)
462 int c = (unsigned char) *buf++;
464 switch (telnet_state) {
467 if (c == NUL && telnet_state == SEENCR)
468 telnet_state = TOPLEVEL;
470 telnet_state = SEENIAC;
476 /* I can't get the F***ing winsock to insert the urgent IAC
477 * into the right position! Even with SO_OOBINLINE it gives
478 * it to recv too soon. And of course the DM byte (that
479 * arrives in the same packet!) appears several K later!!
481 * Oh well, we do get the DM in the right place so I'll
482 * just stop hiding on the next 0xf2 and hope for the best.
488 telnet_state = SEENCR;
490 telnet_state = TOPLEVEL;
495 telnet_state = SEENDO;
497 telnet_state = SEENDONT;
499 telnet_state = SEENWILL;
501 telnet_state = SEENWONT;
503 telnet_state = SEENSB;
506 telnet_state = TOPLEVEL;
508 /* ignore everything else; print it if it's IAC */
512 telnet_state = TOPLEVEL;
516 proc_rec_opt(WILL, c);
517 telnet_state = TOPLEVEL;
520 proc_rec_opt(WONT, c);
521 telnet_state = TOPLEVEL;
525 telnet_state = TOPLEVEL;
528 proc_rec_opt(DONT, c);
529 telnet_state = TOPLEVEL;
534 telnet_state = SUBNEGOT;
538 telnet_state = SUBNEG_IAC;
541 if (sb_len >= sb_size) {
545 srealloc(sb_buf, sb_size) :
552 if (sb_len < sb_size)
553 sb_buf[sb_len++] = c;
554 telnet_state = SUBNEGOT; /* in case we came here by goto */
559 goto subneg_addchar; /* yes, it's a hack, I know, but... */
562 telnet_state = TOPLEVEL;
569 static int telnet_closing(Plug plug, char *error_msg, int error_code,
577 /* A socket error has occurred. */
578 connection_fatal(error_msg);
579 } /* Otherwise, the remote side closed the connection normally. */
583 static int telnet_receive(Plug plug, int urgent, char *data, int len)
587 do_telnet_read(data, len);
591 static void telnet_sent(Plug plug, int bufsize)
593 telnet_bufsize = bufsize;
597 * Called to set up the Telnet connection.
599 * Returns an error message, or NULL on success.
601 * Also places the canonical host name into `realhost'. It must be
602 * freed by the caller.
604 static char *telnet_init(char *host, int port, char **realhost)
606 static struct plug_function_table fn_table = {
610 }, *fn_table_ptr = &fn_table;
620 sprintf(buf, "Looking up host \"%.170s\"", host);
623 addr = sk_namelookup(host, realhost);
624 if ((err = sk_addr_error(addr)))
628 port = 23; /* default telnet port */
634 char buf[200], addrbuf[100];
635 sk_getaddr(addr, addrbuf, 100);
636 sprintf(buf, "Connecting to %.100s port %d", addrbuf, port);
639 s = sk_new(addr, port, 0, 1, &fn_table_ptr);
640 if ((err = sk_socket_error(s)))
646 * Initialise option states.
648 if (cfg.passive_telnet) {
651 for (o = opts; *o; o++)
652 if ((*o)->state == REQUESTED)
653 (*o)->state = INACTIVE;
657 for (o = opts; *o; o++)
658 if ((*o)->state == REQUESTED)
659 send_opt((*o)->send, (*o)->option);
664 * Set up SYNCH state.
672 * Called to send data down the Telnet connection.
674 static int telnet_send(char *buf, int len)
677 static unsigned char iac[2] = { IAC, IAC };
678 static unsigned char cr[2] = { CR, NUL };
680 static unsigned char nl[2] = { CR, LF };
687 while (p < buf + len) {
690 while (iswritable((unsigned char) *p) && p < buf + len)
692 telnet_bufsize = sk_write(s, q, p - q);
694 while (p < buf + len && !iswritable((unsigned char) *p)) {
696 sk_write(s, (unsigned char) *p == IAC ? iac : cr, 2);
701 return telnet_bufsize;
705 * Called to query the current socket sendability status.
707 static int telnet_sendbuffer(void)
709 return telnet_bufsize;
713 * Called to set the size of the window from Telnet's POV.
715 static void telnet_size(void)
720 if (s == NULL || o_naws.state != ACTIVE)
731 telnet_bufsize = sk_write(s, b, 9);
732 sprintf(logbuf, "client:\tSB NAWS %d,%d",
733 ((unsigned char) b[3] << 8) + (unsigned char) b[4],
734 ((unsigned char) b[5] << 8) + (unsigned char) b[6]);
739 * Send Telnet special codes.
741 static void telnet_special(Telnet_Special code)
752 telnet_bufsize = sk_write(s, b, 2);
756 telnet_bufsize = sk_write(s, b, 2);
760 telnet_bufsize = sk_write(s, b, 2);
764 telnet_bufsize = sk_write(s, b, 2);
768 telnet_bufsize = sk_write(s, b, 2);
772 telnet_bufsize = sk_write(s, b, 2);
776 telnet_bufsize = sk_write(s, b, 2);
780 telnet_bufsize = sk_write(s, b, 2);
784 telnet_bufsize = sk_write(s, b, 2);
788 telnet_bufsize = sk_write(s, b, 2);
792 telnet_bufsize = sk_write(s, b, 2);
796 telnet_bufsize = sk_write(s, b, 2);
799 telnet_bufsize = sk_write(s, "\r\n", 2);
803 telnet_bufsize = sk_write(s, b, 1);
804 telnet_bufsize = sk_write_oob(s, b + 1, 1);
807 if (o_echo.state == INACTIVE || o_echo.state == REALLY_INACTIVE) {
808 o_echo.state = REQUESTED;
809 send_opt(o_echo.send, o_echo.option);
813 if (o_echo.state == ACTIVE) {
814 o_echo.state = REQUESTED;
815 send_opt(o_echo.nsend, o_echo.option);
819 if (o_they_sga.state == ACTIVE) {
821 telnet_bufsize = sk_write(s, b, 2);
827 static Socket telnet_socket(void)
832 static int telnet_sendok(void)
837 static void telnet_unthrottle(int backlog)
839 sk_set_frozen(s, backlog > TELNET_MAX_BACKLOG);
842 static int telnet_ldisc(int option)
844 if (option == LD_ECHO)
846 if (option == LD_EDIT)
851 Backend telnet_backend = {