18 #define IAC 255 /* interpret as command: */
19 #define DONT 254 /* you are not to use option */
20 #define DO 253 /* please, you use option */
21 #define WONT 252 /* I won't use option */
22 #define WILL 251 /* I will use option */
23 #define SB 250 /* interpret as subnegotiation */
24 #define SE 240 /* end sub negotiation */
26 #define GA 249 /* you may reverse the line */
27 #define EL 248 /* erase the current line */
28 #define EC 247 /* erase the current character */
29 #define AYT 246 /* are you there */
30 #define AO 245 /* abort output--but let prog finish */
31 #define IP 244 /* interrupt process--permanently */
32 #define BREAK 243 /* break */
33 #define DM 242 /* data mark--for connect. cleaning */
34 #define NOP 241 /* nop */
35 #define EOR 239 /* end of record (transparent mode) */
36 #define ABORT 238 /* Abort process */
37 #define SUSP 237 /* Suspend process */
38 #define xEOF 236 /* End of file: EOF is already used... */
41 X(BINARY, 0) /* 8-bit data path */ \
42 X(ECHO, 1) /* echo */ \
43 X(RCP, 2) /* prepare to reconnect */ \
44 X(SGA, 3) /* suppress go ahead */ \
45 X(NAMS, 4) /* approximate message size */ \
46 X(STATUS, 5) /* give status */ \
47 X(TM, 6) /* timing mark */ \
48 X(RCTE, 7) /* remote controlled transmission and echo */ \
49 X(NAOL, 8) /* negotiate about output line width */ \
50 X(NAOP, 9) /* negotiate about output page size */ \
51 X(NAOCRD, 10) /* negotiate about CR disposition */ \
52 X(NAOHTS, 11) /* negotiate about horizontal tabstops */ \
53 X(NAOHTD, 12) /* negotiate about horizontal tab disposition */ \
54 X(NAOFFD, 13) /* negotiate about formfeed disposition */ \
55 X(NAOVTS, 14) /* negotiate about vertical tab stops */ \
56 X(NAOVTD, 15) /* negotiate about vertical tab disposition */ \
57 X(NAOLFD, 16) /* negotiate about output LF disposition */ \
58 X(XASCII, 17) /* extended ascic character set */ \
59 X(LOGOUT, 18) /* force logout */ \
60 X(BM, 19) /* byte macro */ \
61 X(DET, 20) /* data entry terminal */ \
62 X(SUPDUP, 21) /* supdup protocol */ \
63 X(SUPDUPOUTPUT, 22) /* supdup output */ \
64 X(SNDLOC, 23) /* send location */ \
65 X(TTYPE, 24) /* terminal type */ \
66 X(EOR, 25) /* end or record */ \
67 X(TUID, 26) /* TACACS user identification */ \
68 X(OUTMRK, 27) /* output marking */ \
69 X(TTYLOC, 28) /* terminal location number */ \
70 X(3270REGIME, 29) /* 3270 regime */ \
71 X(X3PAD, 30) /* X.3 PAD */ \
72 X(NAWS, 31) /* window size */ \
73 X(TSPEED, 32) /* terminal speed */ \
74 X(LFLOW, 33) /* remote flow control */ \
75 X(LINEMODE, 34) /* Linemode option */ \
76 X(XDISPLOC, 35) /* X Display Location */ \
77 X(OLD_ENVIRON, 36) /* Old - Environment variables */ \
78 X(AUTHENTICATION, 37) /* Authenticate */ \
79 X(ENCRYPT, 38) /* Encryption option */ \
80 X(NEW_ENVIRON, 39) /* New - Environment variables */ \
81 X(TN3270E, 40) /* TN3270 enhancements */ \
83 X(CHARSET, 42) /* Character set */ \
84 X(RSP, 43) /* Remote serial port */ \
85 X(COM_PORT_OPTION, 44) /* Com port control */ \
86 X(SLE, 45) /* Suppress local echo */ \
87 X(STARTTLS, 46) /* Start TLS */ \
88 X(KERMIT, 47) /* Automatic Kermit file transfer */ \
91 X(PRAGMA_LOGON, 138) \
93 X(PRAGMA_HEARTBEAT, 140) \
94 X(EXOPL, 255) /* extended-options-list */
96 #define telnet_enum(x,y) TELOPT_##x = y,
97 enum { TELOPTS(telnet_enum) dummy=0 };
100 #define TELQUAL_IS 0 /* option is... */
101 #define TELQUAL_SEND 1 /* send option */
102 #define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
112 #define iswritable(x) \
114 (telnet->opt_states[o_we_bin.index] == ACTIVE || (x) != CR))
116 static char *telopt(int opt)
118 #define telnet_str(x,y) case TELOPT_##x: return #x;
127 static void telnet_size(void *handle, int width, int height);
130 int send; /* what we initially send */
131 int nsend; /* -ve send if requested to stop it */
132 int ack, nak; /* +ve and -ve acknowledgements */
133 int option; /* the option code */
134 int index; /* index into telnet->opt_states[] */
136 REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE
154 static const struct Opt o_naws =
155 { WILL, WONT, DO, DONT, TELOPT_NAWS, OPTINDEX_NAWS, REQUESTED };
156 static const struct Opt o_tspeed =
157 { WILL, WONT, DO, DONT, TELOPT_TSPEED, OPTINDEX_TSPEED, REQUESTED };
158 static const struct Opt o_ttype =
159 { WILL, WONT, DO, DONT, TELOPT_TTYPE, OPTINDEX_TTYPE, REQUESTED };
160 static const struct Opt o_oenv =
161 { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON, OPTINDEX_OENV, INACTIVE };
162 static const struct Opt o_nenv =
163 { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON, OPTINDEX_NENV, REQUESTED };
164 static const struct Opt o_echo =
165 { DO, DONT, WILL, WONT, TELOPT_ECHO, OPTINDEX_ECHO, REQUESTED };
166 static const struct Opt o_we_sga =
167 { WILL, WONT, DO, DONT, TELOPT_SGA, OPTINDEX_WE_SGA, REQUESTED };
168 static const struct Opt o_they_sga =
169 { DO, DONT, WILL, WONT, TELOPT_SGA, OPTINDEX_THEY_SGA, REQUESTED };
170 static const struct Opt o_we_bin =
171 { WILL, WONT, DO, DONT, TELOPT_BINARY, OPTINDEX_WE_BIN, INACTIVE };
172 static const struct Opt o_they_bin =
173 { DO, DONT, WILL, WONT, TELOPT_BINARY, OPTINDEX_THEY_BIN, INACTIVE };
175 static const struct Opt *const opts[] = {
176 &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,
177 &o_we_sga, &o_they_sga, &o_we_bin, &o_they_bin, NULL
180 typedef struct telnet_tag {
181 const struct plug_function_table *fn;
182 /* the above field _must_ be first in the structure */
185 int closed_on_socket_error;
189 int term_width, term_height;
191 int opt_states[NUM_OPTS];
193 int echoing, editing;
198 unsigned char *sb_buf;
202 TOP_LEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
203 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
211 #define TELNET_MAX_BACKLOG 4096
213 #define SB_DELTA 1024
215 static void c_write(Telnet telnet, char *buf, int len)
218 backlog = from_backend(telnet->frontend, 0, buf, len);
219 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
222 static void log_option(Telnet telnet, char *sender, int cmd, int option)
226 * The strange-looking "<?""?>" below is there to avoid a
227 * trigraph - a double question mark followed by > maps to a
228 * closing brace character!
230 buf = dupprintf("%s:\t%s %s", sender,
231 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
232 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<?""?>"),
234 logevent(telnet->frontend, buf);
238 static void send_opt(Telnet telnet, int cmd, int option)
245 telnet->bufsize = sk_write(telnet->s, (char *)b, 3);
246 log_option(telnet, "client", cmd, option);
249 static void deactivate_option(Telnet telnet, const struct Opt *o)
251 if (telnet->opt_states[o->index] == REQUESTED ||
252 telnet->opt_states[o->index] == ACTIVE)
253 send_opt(telnet, o->nsend, o->option);
254 telnet->opt_states[o->index] = REALLY_INACTIVE;
258 * Generate side effects of enabling or disabling an option.
260 static void option_side_effects(Telnet telnet, const struct Opt *o, int enabled)
262 if (o->option == TELOPT_ECHO && o->send == DO)
263 telnet->echoing = !enabled;
264 else if (o->option == TELOPT_SGA && o->send == DO)
265 telnet->editing = !enabled;
266 if (telnet->ldisc) /* cause ldisc to notice the change */
267 ldisc_send(telnet->ldisc, NULL, 0, 0);
269 /* Ensure we get the minimum options */
270 if (!telnet->activated) {
271 if (telnet->opt_states[o_echo.index] == INACTIVE) {
272 telnet->opt_states[o_echo.index] = REQUESTED;
273 send_opt(telnet, o_echo.send, o_echo.option);
275 if (telnet->opt_states[o_we_sga.index] == INACTIVE) {
276 telnet->opt_states[o_we_sga.index] = REQUESTED;
277 send_opt(telnet, o_we_sga.send, o_we_sga.option);
279 if (telnet->opt_states[o_they_sga.index] == INACTIVE) {
280 telnet->opt_states[o_they_sga.index] = REQUESTED;
281 send_opt(telnet, o_they_sga.send, o_they_sga.option);
283 telnet->activated = TRUE;
287 static void activate_option(Telnet telnet, const struct Opt *o)
289 if (o->send == WILL && o->option == TELOPT_NAWS)
290 telnet_size(telnet, telnet->term_width, telnet->term_height);
291 if (o->send == WILL &&
292 (o->option == TELOPT_NEW_ENVIRON ||
293 o->option == TELOPT_OLD_ENVIRON)) {
295 * We may only have one kind of ENVIRON going at a time.
296 * This is a hack, but who cares.
298 deactivate_option(telnet, o->option ==
299 TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
301 option_side_effects(telnet, o, 1);
304 static void refused_option(Telnet telnet, const struct Opt *o)
306 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
307 telnet->opt_states[o_oenv.index] == INACTIVE) {
308 send_opt(telnet, WILL, TELOPT_OLD_ENVIRON);
309 telnet->opt_states[o_oenv.index] = REQUESTED;
311 option_side_effects(telnet, o, 0);
314 static void proc_rec_opt(Telnet telnet, int cmd, int option)
316 const struct Opt *const *o;
318 log_option(telnet, "server", cmd, option);
319 for (o = opts; *o; o++) {
320 if ((*o)->option == option && (*o)->ack == cmd) {
321 switch (telnet->opt_states[(*o)->index]) {
323 telnet->opt_states[(*o)->index] = ACTIVE;
324 activate_option(telnet, *o);
329 telnet->opt_states[(*o)->index] = ACTIVE;
330 send_opt(telnet, (*o)->send, option);
331 activate_option(telnet, *o);
333 case REALLY_INACTIVE:
334 send_opt(telnet, (*o)->nsend, option);
338 } else if ((*o)->option == option && (*o)->nak == cmd) {
339 switch (telnet->opt_states[(*o)->index]) {
341 telnet->opt_states[(*o)->index] = INACTIVE;
342 refused_option(telnet, *o);
345 telnet->opt_states[(*o)->index] = INACTIVE;
346 send_opt(telnet, (*o)->nsend, option);
347 option_side_effects(telnet, *o, 0);
350 case REALLY_INACTIVE:
357 * If we reach here, the option was one we weren't prepared to
358 * cope with. If the request was positive (WILL or DO), we send
359 * a negative ack to indicate refusal. If the request was
360 * negative (WONT / DONT), we must do nothing.
362 if (cmd == WILL || cmd == DO)
363 send_opt(telnet, (cmd == WILL ? DONT : WONT), option);
366 static void process_subneg(Telnet telnet)
368 unsigned char *b, *p, *q;
369 int var, value, n, bsize;
370 char *e, *eval, *ekey, *user;
372 switch (telnet->sb_opt) {
374 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
376 char *termspeed = conf_get_str(telnet->conf, CONF_termspeed);
377 b = snewn(20 + strlen(termspeed), unsigned char);
380 b[2] = TELOPT_TSPEED;
382 strcpy((char *)(b + 4), termspeed);
383 n = 4 + strlen(termspeed);
386 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 2);
387 logevent(telnet->frontend, "server:\tSB TSPEED SEND");
388 logbuf = dupprintf("client:\tSB TSPEED IS %s", termspeed);
389 logevent(telnet->frontend, logbuf);
393 logevent(telnet->frontend, "server:\tSB TSPEED <something weird>");
396 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
398 char *termtype = conf_get_str(telnet->conf, CONF_termtype);
399 b = snewn(20 + strlen(termtype), unsigned char);
404 for (n = 0; termtype[n]; n++)
405 b[n + 4] = (termtype[n] >= 'a' && termtype[n] <= 'z' ?
406 termtype[n] + 'A' - 'a' :
410 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 6);
412 logevent(telnet->frontend, "server:\tSB TTYPE SEND");
413 logbuf = dupprintf("client:\tSB TTYPE IS %s", b + 4);
414 logevent(telnet->frontend, logbuf);
418 logevent(telnet->frontend, "server:\tSB TTYPE <something weird>\r\n");
420 case TELOPT_OLD_ENVIRON:
421 case TELOPT_NEW_ENVIRON:
423 q = p + telnet->sb_len;
424 if (p < q && *p == TELQUAL_SEND) {
427 logbuf = dupprintf("server:\tSB %s SEND", telopt(telnet->sb_opt));
428 logevent(telnet->frontend, logbuf);
430 if (telnet->sb_opt == TELOPT_OLD_ENVIRON) {
431 if (conf_get_int(telnet->conf, CONF_rfc_environ)) {
439 * Try to guess the sense of VAR and VALUE.
445 } else if (*p == BSD_VAR) {
453 * With NEW_ENVIRON, the sense of VAR and VALUE
460 for (eval = conf_get_str_strs(telnet->conf, CONF_environmt,
463 eval = conf_get_str_strs(telnet->conf, CONF_environmt,
465 bsize += strlen(ekey) + strlen(eval) + 2;
466 user = get_remote_username(telnet->conf);
468 bsize += 6 + strlen(user);
470 b = snewn(bsize, unsigned char);
473 b[2] = telnet->sb_opt;
476 for (eval = conf_get_str_strs(telnet->conf, CONF_environmt,
479 eval = conf_get_str_strs(telnet->conf, CONF_environmt,
482 for (e = ekey; *e; e++)
485 for (e = eval; *e; e++)
495 for (e = user; *e; e++)
500 telnet->bufsize = sk_write(telnet->s, (char *)b, n);
502 logbuf = dupprintf("client:\tSB %s IS <nothing>",
503 telopt(telnet->sb_opt));
504 logevent(telnet->frontend, logbuf);
507 logbuf = dupprintf("client:\tSB %s IS:",
508 telopt(telnet->sb_opt));
509 logevent(telnet->frontend, logbuf);
511 for (eval = conf_get_str_strs(telnet->conf, CONF_environmt,
514 eval = conf_get_str_strs(telnet->conf, CONF_environmt,
516 logbuf = dupprintf("\t%s=%s", ekey, eval);
517 logevent(telnet->frontend, logbuf);
521 logbuf = dupprintf("\tUSER=%s", user);
522 logevent(telnet->frontend, logbuf);
533 static void do_telnet_read(Telnet telnet, char *buf, int len)
536 int outbuflen = 0, outbufsize = 0;
538 #define ADDTOBUF(c) do { \
539 if (outbuflen >= outbufsize) { \
540 outbufsize = outbuflen + 256; \
541 outbuf = sresize(outbuf, outbufsize, char); \
543 outbuf[outbuflen++] = (c); \
547 int c = (unsigned char) *buf++;
549 switch (telnet->state) {
552 if (c == NUL && telnet->state == SEENCR)
553 telnet->state = TOP_LEVEL;
555 telnet->state = SEENIAC;
557 if (!telnet->in_synch)
561 /* I can't get the F***ing winsock to insert the urgent IAC
562 * into the right position! Even with SO_OOBINLINE it gives
563 * it to recv too soon. And of course the DM byte (that
564 * arrives in the same packet!) appears several K later!!
566 * Oh well, we do get the DM in the right place so I'll
567 * just stop hiding on the next 0xf2 and hope for the best.
570 telnet->in_synch = 0;
572 if (c == CR && telnet->opt_states[o_they_bin.index] != ACTIVE)
573 telnet->state = SEENCR;
575 telnet->state = TOP_LEVEL;
580 telnet->state = SEENDO;
582 telnet->state = SEENDONT;
584 telnet->state = SEENWILL;
586 telnet->state = SEENWONT;
588 telnet->state = SEENSB;
590 telnet->in_synch = 0;
591 telnet->state = TOP_LEVEL;
593 /* ignore everything else; print it if it's IAC */
597 telnet->state = TOP_LEVEL;
601 proc_rec_opt(telnet, WILL, c);
602 telnet->state = TOP_LEVEL;
605 proc_rec_opt(telnet, WONT, c);
606 telnet->state = TOP_LEVEL;
609 proc_rec_opt(telnet, DO, c);
610 telnet->state = TOP_LEVEL;
613 proc_rec_opt(telnet, DONT, c);
614 telnet->state = TOP_LEVEL;
619 telnet->state = SUBNEGOT;
623 telnet->state = SUBNEG_IAC;
626 if (telnet->sb_len >= telnet->sb_size) {
627 telnet->sb_size += SB_DELTA;
628 telnet->sb_buf = sresize(telnet->sb_buf, telnet->sb_size,
631 telnet->sb_buf[telnet->sb_len++] = c;
632 telnet->state = SUBNEGOT; /* in case we came here by goto */
637 goto subneg_addchar; /* yes, it's a hack, I know, but... */
639 process_subneg(telnet);
640 telnet->state = TOP_LEVEL;
647 c_write(telnet, outbuf, outbuflen);
651 static void telnet_log(Plug plug, int type, SockAddr addr, int port,
652 const char *error_msg, int error_code)
654 Telnet telnet = (Telnet) plug;
655 char addrbuf[256], *msg;
657 sk_getaddr(addr, addrbuf, lenof(addrbuf));
660 msg = dupprintf("Connecting to %s port %d", addrbuf, port);
662 msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);
664 logevent(telnet->frontend, msg);
668 static int telnet_closing(Plug plug, const char *error_msg, int error_code,
671 Telnet telnet = (Telnet) plug;
674 * We don't implement independent EOF in each direction for Telnet
675 * connections; as soon as we get word that the remote side has
676 * sent us EOF, we wind up the whole connection.
683 telnet->closed_on_socket_error = TRUE;
684 notify_remote_exit(telnet->frontend);
687 logevent(telnet->frontend, error_msg);
688 connection_fatal(telnet->frontend, "%s", error_msg);
690 /* Otherwise, the remote side closed the connection normally. */
694 static int telnet_receive(Plug plug, int urgent, char *data, int len)
696 Telnet telnet = (Telnet) plug;
698 telnet->in_synch = TRUE;
699 do_telnet_read(telnet, data, len);
703 static void telnet_sent(Plug plug, int bufsize)
705 Telnet telnet = (Telnet) plug;
706 telnet->bufsize = bufsize;
710 * Called to set up the Telnet connection.
712 * Returns an error message, or NULL on success.
714 * Also places the canonical host name into `realhost'. It must be
715 * freed by the caller.
717 static const char *telnet_init(void *frontend_handle, void **backend_handle,
718 Conf *conf, char *host, int port,
719 char **realhost, int nodelay, int keepalive)
721 static const struct plug_function_table fn_table = {
733 telnet = snew(struct telnet_tag);
734 telnet->fn = &fn_table;
735 telnet->conf = conf_copy(conf);
737 telnet->closed_on_socket_error = FALSE;
738 telnet->echoing = TRUE;
739 telnet->editing = TRUE;
740 telnet->activated = FALSE;
741 telnet->sb_buf = NULL;
743 telnet->frontend = frontend_handle;
744 telnet->term_width = conf_get_int(telnet->conf, CONF_width);
745 telnet->term_height = conf_get_int(telnet->conf, CONF_height);
746 telnet->state = TOP_LEVEL;
747 telnet->ldisc = NULL;
748 telnet->pinger = NULL;
749 *backend_handle = telnet;
756 addressfamily = conf_get_int(telnet->conf, CONF_addressfamily);
757 buf = dupprintf("Looking up host \"%s\"%s", host,
758 (addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
759 (addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" :
761 logevent(telnet->frontend, buf);
764 addr = name_lookup(host, port, realhost, telnet->conf, addressfamily);
765 if ((err = sk_addr_error(addr)) != NULL) {
771 port = 23; /* default telnet port */
776 telnet->s = new_connection(addr, *realhost, port, 0, 1,
777 nodelay, keepalive, (Plug) telnet, telnet->conf);
778 if ((err = sk_socket_error(telnet->s)) != NULL)
781 telnet->pinger = pinger_new(telnet->conf, &telnet_backend, telnet);
784 * Initialise option states.
786 if (conf_get_int(telnet->conf, CONF_passive_telnet)) {
787 const struct Opt *const *o;
789 for (o = opts; *o; o++)
790 telnet->opt_states[(*o)->index] = INACTIVE;
792 const struct Opt *const *o;
794 for (o = opts; *o; o++) {
795 telnet->opt_states[(*o)->index] = (*o)->initial_state;
796 if (telnet->opt_states[(*o)->index] == REQUESTED)
797 send_opt(telnet, (*o)->send, (*o)->option);
799 telnet->activated = TRUE;
803 * Set up SYNCH state.
805 telnet->in_synch = FALSE;
808 * We can send special commands from the start.
810 update_specials_menu(telnet->frontend);
813 * loghost overrides realhost, if specified.
815 loghost = conf_get_str(telnet->conf, CONF_loghost);
820 *realhost = dupstr(loghost);
821 colon = strrchr(*realhost, ':');
824 * FIXME: if we ever update this aspect of ssh.c for
825 * IPv6 literal management, this should change in line
835 static void telnet_free(void *handle)
837 Telnet telnet = (Telnet) handle;
839 sfree(telnet->sb_buf);
843 pinger_free(telnet->pinger);
844 conf_free(telnet->conf);
848 * Reconfigure the Telnet backend. There's no immediate action
849 * necessary, in this backend: we just save the fresh config for
850 * any subsequent negotiations.
852 static void telnet_reconfig(void *handle, Conf *conf)
854 Telnet telnet = (Telnet) handle;
855 pinger_reconfig(telnet->pinger, telnet->conf, conf);
856 conf_free(telnet->conf);
857 telnet->conf = conf_copy(conf);
861 * Called to send data down the Telnet connection.
863 static int telnet_send(void *handle, char *buf, int len)
865 Telnet telnet = (Telnet) handle;
866 unsigned char *p, *end;
867 static const unsigned char iac[2] = { IAC, IAC };
868 static const unsigned char cr[2] = { CR, NUL };
870 static const unsigned char nl[2] = { CR, LF };
873 if (telnet->s == NULL)
876 p = (unsigned char *)buf;
877 end = (unsigned char *)(buf + len);
879 unsigned char *q = p;
881 while (p < end && iswritable(*p))
883 telnet->bufsize = sk_write(telnet->s, (char *)q, p - q);
885 while (p < end && !iswritable(*p)) {
887 sk_write(telnet->s, (char *)(*p == IAC ? iac : cr), 2);
892 return telnet->bufsize;
896 * Called to query the current socket sendability status.
898 static int telnet_sendbuffer(void *handle)
900 Telnet telnet = (Telnet) handle;
901 return telnet->bufsize;
905 * Called to set the size of the window from Telnet's POV.
907 static void telnet_size(void *handle, int width, int height)
909 Telnet telnet = (Telnet) handle;
914 telnet->term_width = width;
915 telnet->term_height = height;
917 if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)
922 b[n++] = TELOPT_NAWS;
923 b[n++] = telnet->term_width >> 8;
924 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
925 b[n++] = telnet->term_width & 0xFF;
926 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
927 b[n++] = telnet->term_height >> 8;
928 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
929 b[n++] = telnet->term_height & 0xFF;
930 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
933 telnet->bufsize = sk_write(telnet->s, (char *)b, n);
934 logbuf = dupprintf("client:\tSB NAWS %d,%d",
935 telnet->term_width, telnet->term_height);
936 logevent(telnet->frontend, logbuf);
941 * Send Telnet special codes.
943 static void telnet_special(void *handle, Telnet_Special code)
945 Telnet telnet = (Telnet) handle;
948 if (telnet->s == NULL)
955 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
959 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
963 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
967 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
971 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
975 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
979 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
983 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
987 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
991 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
995 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
999 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
1002 /* In BINARY mode, CR-LF becomes just CR -
1003 * and without the NUL suffix too. */
1004 if (telnet->opt_states[o_we_bin.index] == ACTIVE)
1005 telnet->bufsize = sk_write(telnet->s, "\r", 1);
1007 telnet->bufsize = sk_write(telnet->s, "\r\n", 2);
1011 telnet->bufsize = sk_write(telnet->s, (char *)b, 1);
1012 telnet->bufsize = sk_write_oob(telnet->s, (char *)(b + 1), 1);
1015 if (telnet->opt_states[o_echo.index] == INACTIVE ||
1016 telnet->opt_states[o_echo.index] == REALLY_INACTIVE) {
1017 telnet->opt_states[o_echo.index] = REQUESTED;
1018 send_opt(telnet, o_echo.send, o_echo.option);
1022 if (telnet->opt_states[o_echo.index] == ACTIVE) {
1023 telnet->opt_states[o_echo.index] = REQUESTED;
1024 send_opt(telnet, o_echo.nsend, o_echo.option);
1028 if (telnet->opt_states[o_they_sga.index] == ACTIVE) {
1030 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
1034 break; /* never heard of it */
1038 static const struct telnet_special *telnet_get_specials(void *handle)
1040 static const struct telnet_special specials[] = {
1041 {"Are You There", TS_AYT},
1043 {"Synch", TS_SYNCH},
1044 {"Erase Character", TS_EC},
1045 {"Erase Line", TS_EL},
1046 {"Go Ahead", TS_GA},
1047 {"No Operation", TS_NOP},
1049 {"Abort Process", TS_ABORT},
1050 {"Abort Output", TS_AO},
1051 {"Interrupt Process", TS_IP},
1052 {"Suspend Process", TS_SUSP},
1054 {"End Of Record", TS_EOR},
1055 {"End Of File", TS_EOF},
1061 static int telnet_connected(void *handle)
1063 Telnet telnet = (Telnet) handle;
1064 return telnet->s != NULL;
1067 static int telnet_sendok(void *handle)
1069 /* Telnet telnet = (Telnet) handle; */
1073 static void telnet_unthrottle(void *handle, int backlog)
1075 Telnet telnet = (Telnet) handle;
1076 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
1079 static int telnet_ldisc(void *handle, int option)
1081 Telnet telnet = (Telnet) handle;
1082 if (option == LD_ECHO)
1083 return telnet->echoing;
1084 if (option == LD_EDIT)
1085 return telnet->editing;
1089 static void telnet_provide_ldisc(void *handle, void *ldisc)
1091 Telnet telnet = (Telnet) handle;
1092 telnet->ldisc = ldisc;
1095 static void telnet_provide_logctx(void *handle, void *logctx)
1097 /* This is a stub. */
1100 static int telnet_exitcode(void *handle)
1102 Telnet telnet = (Telnet) handle;
1103 if (telnet->s != NULL)
1104 return -1; /* still connected */
1105 else if (telnet->closed_on_socket_error)
1106 return INT_MAX; /* a socket error counts as an unclean exit */
1108 /* Telnet doesn't transmit exit codes back to the client */
1113 * cfg_info for Telnet does nothing at all.
1115 static int telnet_cfg_info(void *handle)
1120 Backend telnet_backend = {
1128 telnet_get_specials,
1133 telnet_provide_ldisc,
1134 telnet_provide_logctx,