13 #define IAC 255 /* interpret as command: */
14 #define DONT 254 /* you are not to use option */
15 #define DO 253 /* please, you use option */
16 #define WONT 252 /* I won't use option */
17 #define WILL 251 /* I will use option */
18 #define SB 250 /* interpret as subnegotiation */
19 #define SE 240 /* end sub negotiation */
21 #define GA 249 /* you may reverse the line */
22 #define EL 248 /* erase the current line */
23 #define EC 247 /* erase the current character */
24 #define AYT 246 /* are you there */
25 #define AO 245 /* abort output--but let prog finish */
26 #define IP 244 /* interrupt process--permanently */
27 #define BREAK 243 /* break */
28 #define DM 242 /* data mark--for connect. cleaning */
29 #define NOP 241 /* nop */
30 #define EOR 239 /* end of record (transparent mode) */
31 #define ABORT 238 /* Abort process */
32 #define SUSP 237 /* Suspend process */
33 #define xEOF 236 /* End of file: EOF is already used... */
35 #define TELOPT_BINARY 0 /* 8-bit data path */
36 #define TELOPT_ECHO 1 /* echo */
37 #define TELOPT_RCP 2 /* prepare to reconnect */
38 #define TELOPT_SGA 3 /* suppress go ahead */
39 #define TELOPT_NAMS 4 /* approximate message size */
40 #define TELOPT_STATUS 5 /* give status */
41 #define TELOPT_TM 6 /* timing mark */
42 #define TELOPT_RCTE 7 /* remote controlled transmission and echo */
43 #define TELOPT_NAOL 8 /* negotiate about output line width */
44 #define TELOPT_NAOP 9 /* negotiate about output page size */
45 #define TELOPT_NAOCRD 10 /* negotiate about CR disposition */
46 #define TELOPT_NAOHTS 11 /* negotiate about horizontal tabstops */
47 #define TELOPT_NAOHTD 12 /* negotiate about horizontal tab disposition */
48 #define TELOPT_NAOFFD 13 /* negotiate about formfeed disposition */
49 #define TELOPT_NAOVTS 14 /* negotiate about vertical tab stops */
50 #define TELOPT_NAOVTD 15 /* negotiate about vertical tab disposition */
51 #define TELOPT_NAOLFD 16 /* negotiate about output LF disposition */
52 #define TELOPT_XASCII 17 /* extended ascic character set */
53 #define TELOPT_LOGOUT 18 /* force logout */
54 #define TELOPT_BM 19 /* byte macro */
55 #define TELOPT_DET 20 /* data entry terminal */
56 #define TELOPT_SUPDUP 21 /* supdup protocol */
57 #define TELOPT_SUPDUPOUTPUT 22 /* supdup output */
58 #define TELOPT_SNDLOC 23 /* send location */
59 #define TELOPT_TTYPE 24 /* terminal type */
60 #define TELOPT_EOR 25 /* end or record */
61 #define TELOPT_TUID 26 /* TACACS user identification */
62 #define TELOPT_OUTMRK 27 /* output marking */
63 #define TELOPT_TTYLOC 28 /* terminal location number */
64 #define TELOPT_3270REGIME 29 /* 3270 regime */
65 #define TELOPT_X3PAD 30 /* X.3 PAD */
66 #define TELOPT_NAWS 31 /* window size */
67 #define TELOPT_TSPEED 32 /* terminal speed */
68 #define TELOPT_LFLOW 33 /* remote flow control */
69 #define TELOPT_LINEMODE 34 /* Linemode option */
70 #define TELOPT_XDISPLOC 35 /* X Display Location */
71 #define TELOPT_OLD_ENVIRON 36 /* Old - Environment variables */
72 #define TELOPT_AUTHENTICATION 37 /* Authenticate */
73 #define TELOPT_ENCRYPT 38 /* Encryption option */
74 #define TELOPT_NEW_ENVIRON 39 /* New - Environment variables */
75 #define TELOPT_EXOPL 255 /* extended-options-list */
77 #define TELQUAL_IS 0 /* option is... */
78 #define TELQUAL_SEND 1 /* send option */
79 #define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
89 #define iswritable(x) \
91 (telnet->opt_states[o_we_bin.index] == ACTIVE || (x) != CR))
93 static char *telopt(int opt)
95 #define i(x) if (opt == TELOPT_ ## x) return #x;
140 static void telnet_size(void *handle, int width, int height);
143 int send; /* what we initially send */
144 int nsend; /* -ve send if requested to stop it */
145 int ack, nak; /* +ve and -ve acknowledgements */
146 int option; /* the option code */
147 int index; /* index into telnet->opt_states[] */
149 REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE
167 static const struct Opt o_naws =
168 { WILL, WONT, DO, DONT, TELOPT_NAWS, OPTINDEX_NAWS, REQUESTED };
169 static const struct Opt o_tspeed =
170 { WILL, WONT, DO, DONT, TELOPT_TSPEED, OPTINDEX_TSPEED, REQUESTED };
171 static const struct Opt o_ttype =
172 { WILL, WONT, DO, DONT, TELOPT_TTYPE, OPTINDEX_TTYPE, REQUESTED };
173 static const struct Opt o_oenv = { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON,
174 OPTINDEX_OENV, INACTIVE
176 static const struct Opt o_nenv = { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON,
177 OPTINDEX_NENV, REQUESTED
179 static const struct Opt o_echo =
180 { DO, DONT, WILL, WONT, TELOPT_ECHO, OPTINDEX_ECHO, REQUESTED };
181 static const struct Opt o_we_sga =
182 { WILL, WONT, DO, DONT, TELOPT_SGA, OPTINDEX_WE_SGA, REQUESTED };
183 static const struct Opt o_they_sga =
184 { DO, DONT, WILL, WONT, TELOPT_SGA, OPTINDEX_THEY_SGA, REQUESTED };
185 static const struct Opt o_we_bin =
186 { WILL, WONT, DO, DONT, TELOPT_BINARY, OPTINDEX_WE_BIN, INACTIVE };
187 static const struct Opt o_they_bin =
188 { DO, DONT, WILL, WONT, TELOPT_BINARY, OPTINDEX_THEY_BIN, INACTIVE };
190 static const struct Opt *const opts[] = {
191 &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,
192 &o_we_sga, &o_they_sga, &o_we_bin, &o_they_bin, NULL
195 typedef struct telnet_tag {
196 const struct plug_function_table *fn;
197 /* the above field _must_ be first in the structure */
203 int term_width, term_height;
205 int opt_states[NUM_OPTS];
207 int echoing, editing;
212 unsigned char *sb_buf;
216 TOP_LEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
217 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
222 #define TELNET_MAX_BACKLOG 4096
224 #define SB_DELTA 1024
226 static void c_write1(Telnet telnet, int c)
230 backlog = from_backend(telnet->frontend, 0, &cc, 1);
231 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
234 static void log_option(Telnet telnet, char *sender, int cmd, int option)
238 * The strange-looking "<?""?>" below is there to avoid a
239 * trigraph - a double question mark followed by > maps to a
240 * closing brace character!
242 buf = dupprintf("%s:\t%s %s", sender,
243 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
244 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<?""?>"),
246 logevent(telnet->frontend, buf);
250 static void send_opt(Telnet telnet, int cmd, int option)
257 telnet->bufsize = sk_write(telnet->s, (char *)b, 3);
258 log_option(telnet, "client", cmd, option);
261 static void deactivate_option(Telnet telnet, const struct Opt *o)
263 if (telnet->opt_states[o->index] == REQUESTED ||
264 telnet->opt_states[o->index] == ACTIVE)
265 send_opt(telnet, o->nsend, o->option);
266 telnet->opt_states[o->index] = REALLY_INACTIVE;
270 * Generate side effects of enabling or disabling an option.
272 static void option_side_effects(Telnet telnet, const struct Opt *o, int enabled)
274 if (o->option == TELOPT_ECHO && o->send == DO)
275 telnet->echoing = !enabled;
276 else if (o->option == TELOPT_SGA && o->send == DO)
277 telnet->editing = !enabled;
278 if (telnet->ldisc) /* cause ldisc to notice the change */
279 ldisc_send(telnet->ldisc, NULL, 0, 0);
281 /* Ensure we get the minimum options */
282 if (!telnet->activated) {
283 if (telnet->opt_states[o_echo.index] == INACTIVE) {
284 telnet->opt_states[o_echo.index] = REQUESTED;
285 send_opt(telnet, o_echo.send, o_echo.option);
287 if (telnet->opt_states[o_we_sga.index] == INACTIVE) {
288 telnet->opt_states[o_we_sga.index] = REQUESTED;
289 send_opt(telnet, o_we_sga.send, o_we_sga.option);
291 if (telnet->opt_states[o_they_sga.index] == INACTIVE) {
292 telnet->opt_states[o_they_sga.index] = REQUESTED;
293 send_opt(telnet, o_they_sga.send, o_they_sga.option);
295 telnet->activated = TRUE;
299 static void activate_option(Telnet telnet, const struct Opt *o)
301 if (o->send == WILL && o->option == TELOPT_NAWS)
302 telnet_size(telnet, telnet->term_width, telnet->term_height);
303 if (o->send == WILL &&
304 (o->option == TELOPT_NEW_ENVIRON ||
305 o->option == TELOPT_OLD_ENVIRON)) {
307 * We may only have one kind of ENVIRON going at a time.
308 * This is a hack, but who cares.
310 deactivate_option(telnet, o->option ==
311 TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
313 option_side_effects(telnet, o, 1);
316 static void refused_option(Telnet telnet, const struct Opt *o)
318 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
319 telnet->opt_states[o_oenv.index] == INACTIVE) {
320 send_opt(telnet, WILL, TELOPT_OLD_ENVIRON);
321 telnet->opt_states[o_oenv.index] = REQUESTED;
323 option_side_effects(telnet, o, 0);
326 static void proc_rec_opt(Telnet telnet, int cmd, int option)
328 const struct Opt *const *o;
330 log_option(telnet, "server", cmd, option);
331 for (o = opts; *o; o++) {
332 if ((*o)->option == option && (*o)->ack == cmd) {
333 switch (telnet->opt_states[(*o)->index]) {
335 telnet->opt_states[(*o)->index] = ACTIVE;
336 activate_option(telnet, *o);
341 telnet->opt_states[(*o)->index] = ACTIVE;
342 send_opt(telnet, (*o)->send, option);
343 activate_option(telnet, *o);
345 case REALLY_INACTIVE:
346 send_opt(telnet, (*o)->nsend, option);
350 } else if ((*o)->option == option && (*o)->nak == cmd) {
351 switch (telnet->opt_states[(*o)->index]) {
353 telnet->opt_states[(*o)->index] = INACTIVE;
354 refused_option(telnet, *o);
357 telnet->opt_states[(*o)->index] = INACTIVE;
358 send_opt(telnet, (*o)->nsend, option);
359 option_side_effects(telnet, *o, 0);
362 case REALLY_INACTIVE:
369 * If we reach here, the option was one we weren't prepared to
370 * cope with. So send a negative ack.
372 send_opt(telnet, (cmd == WILL ? DONT : WONT), option);
375 static void process_subneg(Telnet telnet)
377 unsigned char b[2048], *p, *q;
381 switch (telnet->sb_opt) {
383 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
387 b[2] = TELOPT_TSPEED;
389 strcpy((char *)(b + 4), cfg.termspeed);
390 n = 4 + strlen(cfg.termspeed);
393 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 2);
394 logevent(telnet->frontend, "server:\tSB TSPEED SEND");
395 logbuf = dupprintf("client:\tSB TSPEED IS %s", cfg.termspeed);
396 logevent(telnet->frontend, logbuf);
399 logevent(telnet->frontend, "server:\tSB TSPEED <something weird>");
402 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
408 for (n = 0; cfg.termtype[n]; n++)
409 b[n + 4] = (cfg.termtype[n] >= 'a'
410 && cfg.termtype[n] <=
411 'z' ? cfg.termtype[n] + 'A' -
412 'a' : cfg.termtype[n]);
415 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 6);
417 logevent(telnet->frontend, "server:\tSB TTYPE SEND");
418 logbuf = dupprintf("client:\tSB TTYPE IS %s", b + 4);
419 logevent(telnet->frontend, logbuf);
422 logevent(telnet->frontend, "server:\tSB TTYPE <something weird>\r\n");
424 case TELOPT_OLD_ENVIRON:
425 case TELOPT_NEW_ENVIRON:
427 q = p + telnet->sb_len;
428 if (p < q && *p == TELQUAL_SEND) {
431 logbuf = dupprintf("server:\tSB %s SEND", telopt(telnet->sb_opt));
432 logevent(telnet->frontend, logbuf);
434 if (telnet->sb_opt == TELOPT_OLD_ENVIRON) {
435 if (cfg.rfc_environ) {
443 * Try to guess the sense of VAR and VALUE.
449 } else if (*p == BSD_VAR) {
457 * With NEW_ENVIRON, the sense of VAR and VALUE
465 b[2] = telnet->sb_opt;
471 while (*e && *e != '\t')
493 telnet->bufsize = sk_write(telnet->s, (char *)b, n);
494 logbuf = dupprintf("client:\tSB %s IS %s", telopt(telnet->sb_opt),
495 n == 6 ? "<nothing>" : "<stuff>");
496 logevent(telnet->frontend, logbuf);
503 static void do_telnet_read(Telnet telnet, char *buf, int len)
507 int c = (unsigned char) *buf++;
509 switch (telnet->state) {
512 if (c == NUL && telnet->state == SEENCR)
513 telnet->state = TOP_LEVEL;
515 telnet->state = SEENIAC;
517 if (!telnet->in_synch)
521 /* I can't get the F***ing winsock to insert the urgent IAC
522 * into the right position! Even with SO_OOBINLINE it gives
523 * it to recv too soon. And of course the DM byte (that
524 * arrives in the same packet!) appears several K later!!
526 * Oh well, we do get the DM in the right place so I'll
527 * just stop hiding on the next 0xf2 and hope for the best.
530 telnet->in_synch = 0;
532 if (c == CR && telnet->opt_states[o_they_bin.index] != ACTIVE)
533 telnet->state = SEENCR;
535 telnet->state = TOP_LEVEL;
540 telnet->state = SEENDO;
542 telnet->state = SEENDONT;
544 telnet->state = SEENWILL;
546 telnet->state = SEENWONT;
548 telnet->state = SEENSB;
550 telnet->in_synch = 0;
551 telnet->state = TOP_LEVEL;
553 /* ignore everything else; print it if it's IAC */
557 telnet->state = TOP_LEVEL;
561 proc_rec_opt(telnet, WILL, c);
562 telnet->state = TOP_LEVEL;
565 proc_rec_opt(telnet, WONT, c);
566 telnet->state = TOP_LEVEL;
569 proc_rec_opt(telnet, DO, c);
570 telnet->state = TOP_LEVEL;
573 proc_rec_opt(telnet, DONT, c);
574 telnet->state = TOP_LEVEL;
579 telnet->state = SUBNEGOT;
583 telnet->state = SUBNEG_IAC;
586 if (telnet->sb_len >= telnet->sb_size) {
587 unsigned char *newbuf;
588 telnet->sb_size += SB_DELTA;
589 newbuf = (telnet->sb_buf ?
590 srealloc(telnet->sb_buf, telnet->sb_size) :
591 smalloc(telnet->sb_size));
593 telnet->sb_buf = newbuf;
595 telnet->sb_size -= SB_DELTA;
597 if (telnet->sb_len < telnet->sb_size)
598 telnet->sb_buf[telnet->sb_len++] = c;
599 telnet->state = SUBNEGOT; /* in case we came here by goto */
604 goto subneg_addchar; /* yes, it's a hack, I know, but... */
606 process_subneg(telnet);
607 telnet->state = TOP_LEVEL;
614 static int telnet_closing(Plug plug, char *error_msg, int error_code,
617 Telnet telnet = (Telnet) plug;
624 /* A socket error has occurred. */
625 logevent(telnet->frontend, error_msg);
626 connection_fatal("%s", error_msg);
627 } /* Otherwise, the remote side closed the connection normally. */
631 static int telnet_receive(Plug plug, int urgent, char *data, int len)
633 Telnet telnet = (Telnet) plug;
635 telnet->in_synch = TRUE;
636 do_telnet_read(telnet, data, len);
640 static void telnet_sent(Plug plug, int bufsize)
642 Telnet telnet = (Telnet) plug;
643 telnet->bufsize = bufsize;
647 * Called to set up the Telnet connection.
649 * Returns an error message, or NULL on success.
651 * Also places the canonical host name into `realhost'. It must be
652 * freed by the caller.
654 static char *telnet_init(void *frontend_handle, void **backend_handle,
655 char *host, int port, char **realhost, int nodelay)
657 static const struct plug_function_table fn_table = {
666 telnet = smalloc(sizeof(*telnet));
667 telnet->fn = &fn_table;
669 telnet->echoing = TRUE;
670 telnet->editing = TRUE;
671 telnet->activated = FALSE;
672 telnet->sb_buf = NULL;
674 telnet->frontend = frontend_handle;
675 telnet->term_width = cfg.width;
676 telnet->term_height = cfg.height;
677 telnet->state = TOP_LEVEL;
678 *backend_handle = telnet;
685 buf = dupprintf("Looking up host \"%s\"", host);
686 logevent(telnet->frontend, buf);
689 addr = name_lookup(host, port, realhost);
690 if ((err = sk_addr_error(addr)) != NULL)
694 port = 23; /* default telnet port */
700 char *buf, addrbuf[100];
701 sk_getaddr(addr, addrbuf, 100);
702 buf = dupprintf("Connecting to %s port %d", addrbuf, port);
703 logevent(telnet->frontend, buf);
706 telnet->s = new_connection(addr, *realhost, port, 0, 1,
707 nodelay, (Plug) telnet);
708 if ((err = sk_socket_error(telnet->s)) != NULL)
714 * Initialise option states.
716 if (cfg.passive_telnet) {
717 const struct Opt *const *o;
719 for (o = opts; *o; o++)
720 telnet->opt_states[(*o)->index] = INACTIVE;
722 const struct Opt *const *o;
724 for (o = opts; *o; o++) {
725 telnet->opt_states[(*o)->index] = (*o)->initial_state;
726 if (telnet->opt_states[(*o)->index] == REQUESTED)
727 send_opt(telnet, (*o)->send, (*o)->option);
729 telnet->activated = TRUE;
733 * Set up SYNCH state.
735 telnet->in_synch = FALSE;
741 * Called to send data down the Telnet connection.
743 static int telnet_send(void *handle, char *buf, int len)
745 Telnet telnet = (Telnet) handle;
746 unsigned char *p, *end;
747 static unsigned char iac[2] = { IAC, IAC };
748 static unsigned char cr[2] = { CR, NUL };
750 static unsigned char nl[2] = { CR, LF };
753 if (telnet->s == NULL)
756 p = (unsigned char *)buf;
757 end = (unsigned char *)(buf + len);
759 unsigned char *q = p;
761 while (p < end && iswritable(*p))
763 telnet->bufsize = sk_write(telnet->s, (char *)q, p - q);
765 while (p < end && !iswritable(*p)) {
767 sk_write(telnet->s, (char *)(*p == IAC ? iac : cr), 2);
772 return telnet->bufsize;
776 * Called to query the current socket sendability status.
778 static int telnet_sendbuffer(void *handle)
780 Telnet telnet = (Telnet) handle;
781 return telnet->bufsize;
785 * Called to set the size of the window from Telnet's POV.
787 static void telnet_size(void *handle, int width, int height)
789 Telnet telnet = (Telnet) handle;
794 telnet->term_width = width;
795 telnet->term_height = height;
797 if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)
802 b[n++] = TELOPT_NAWS;
803 b[n++] = telnet->term_width >> 8;
804 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
805 b[n++] = telnet->term_width & 0xFF;
806 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
807 b[n++] = telnet->term_height >> 8;
808 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
809 b[n++] = telnet->term_height & 0xFF;
810 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
813 telnet->bufsize = sk_write(telnet->s, (char *)b, n);
814 logbuf = dupprintf("client:\tSB NAWS %d,%d",
815 telnet->term_width, telnet->term_height);
816 logevent(telnet->frontend, logbuf);
821 * Send Telnet special codes.
823 static void telnet_special(void *handle, Telnet_Special code)
825 Telnet telnet = (Telnet) handle;
828 if (telnet->s == NULL)
835 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
839 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
843 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
847 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
851 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
855 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
859 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
863 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
867 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
871 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
875 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
879 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
882 /* In BINARY mode, CR-LF becomes just CR. */
883 if (telnet->opt_states[o_we_bin.index] == ACTIVE)
884 telnet->bufsize = sk_write(telnet->s, "\r", 2);
886 telnet->bufsize = sk_write(telnet->s, "\r\n", 2);
890 telnet->bufsize = sk_write(telnet->s, (char *)b, 1);
891 telnet->bufsize = sk_write_oob(telnet->s, (char *)(b + 1), 1);
894 if (telnet->opt_states[o_echo.index] == INACTIVE ||
895 telnet->opt_states[o_echo.index] == REALLY_INACTIVE) {
896 telnet->opt_states[o_echo.index] = REQUESTED;
897 send_opt(telnet, o_echo.send, o_echo.option);
901 if (telnet->opt_states[o_echo.index] == ACTIVE) {
902 telnet->opt_states[o_echo.index] = REQUESTED;
903 send_opt(telnet, o_echo.nsend, o_echo.option);
907 if (telnet->opt_states[o_they_sga.index] == ACTIVE) {
909 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
915 static Socket telnet_socket(void *handle)
917 Telnet telnet = (Telnet) handle;
921 static int telnet_sendok(void *handle)
923 /* Telnet telnet = (Telnet) handle; */
927 static void telnet_unthrottle(void *handle, int backlog)
929 Telnet telnet = (Telnet) handle;
930 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
933 static int telnet_ldisc(void *handle, int option)
935 Telnet telnet = (Telnet) handle;
936 if (option == LD_ECHO)
937 return telnet->echoing;
938 if (option == LD_EDIT)
939 return telnet->editing;
943 static void telnet_provide_ldisc(void *handle, void *ldisc)
945 Telnet telnet = (Telnet) handle;
946 telnet->ldisc = ldisc;
949 static void telnet_provide_logctx(void *handle, void *logctx)
951 /* This is a stub. */
954 static int telnet_exitcode(void *handle)
956 /* Telnet telnet = (Telnet) handle; */
957 /* Telnet doesn't transmit exit codes back to the client */
961 Backend telnet_backend = {
971 telnet_provide_ldisc,
972 telnet_provide_logctx,