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 const 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;
203 TOP_LEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
204 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
212 #define TELNET_MAX_BACKLOG 4096
214 #define SB_DELTA 1024
216 static void c_write(Telnet telnet, const char *buf, int len)
219 backlog = from_backend(telnet->frontend, 0, buf, len);
220 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
223 static void log_option(Telnet telnet, const char *sender, int cmd, int option)
227 * The strange-looking "<?""?>" below is there to avoid a
228 * trigraph - a double question mark followed by > maps to a
229 * closing brace character!
231 buf = dupprintf("%s:\t%s %s", sender,
232 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
233 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<?""?>"),
235 logevent(telnet->frontend, buf);
239 static void send_opt(Telnet telnet, int cmd, int option)
246 telnet->bufsize = sk_write(telnet->s, (char *)b, 3);
247 log_option(telnet, "client", cmd, option);
250 static void deactivate_option(Telnet telnet, const struct Opt *o)
252 if (telnet->opt_states[o->index] == REQUESTED ||
253 telnet->opt_states[o->index] == ACTIVE)
254 send_opt(telnet, o->nsend, o->option);
255 telnet->opt_states[o->index] = REALLY_INACTIVE;
259 * Generate side effects of enabling or disabling an option.
261 static void option_side_effects(Telnet telnet, const struct Opt *o, int enabled)
263 if (o->option == TELOPT_ECHO && o->send == DO)
264 telnet->echoing = !enabled;
265 else if (o->option == TELOPT_SGA && o->send == DO)
266 telnet->editing = !enabled;
267 if (telnet->ldisc) /* cause ldisc to notice the change */
268 ldisc_echoedit_update(telnet->ldisc);
270 /* Ensure we get the minimum options */
271 if (!telnet->activated) {
272 if (telnet->opt_states[o_echo.index] == INACTIVE) {
273 telnet->opt_states[o_echo.index] = REQUESTED;
274 send_opt(telnet, o_echo.send, o_echo.option);
276 if (telnet->opt_states[o_we_sga.index] == INACTIVE) {
277 telnet->opt_states[o_we_sga.index] = REQUESTED;
278 send_opt(telnet, o_we_sga.send, o_we_sga.option);
280 if (telnet->opt_states[o_they_sga.index] == INACTIVE) {
281 telnet->opt_states[o_they_sga.index] = REQUESTED;
282 send_opt(telnet, o_they_sga.send, o_they_sga.option);
284 telnet->activated = TRUE;
288 static void activate_option(Telnet telnet, const struct Opt *o)
290 if (o->send == WILL && o->option == TELOPT_NAWS)
291 telnet_size(telnet, telnet->term_width, telnet->term_height);
292 if (o->send == WILL &&
293 (o->option == TELOPT_NEW_ENVIRON ||
294 o->option == TELOPT_OLD_ENVIRON)) {
296 * We may only have one kind of ENVIRON going at a time.
297 * This is a hack, but who cares.
299 deactivate_option(telnet, o->option ==
300 TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
302 option_side_effects(telnet, o, 1);
305 static void refused_option(Telnet telnet, const struct Opt *o)
307 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
308 telnet->opt_states[o_oenv.index] == INACTIVE) {
309 send_opt(telnet, WILL, TELOPT_OLD_ENVIRON);
310 telnet->opt_states[o_oenv.index] = REQUESTED;
312 option_side_effects(telnet, o, 0);
315 static void proc_rec_opt(Telnet telnet, int cmd, int option)
317 const struct Opt *const *o;
319 log_option(telnet, "server", cmd, option);
320 for (o = opts; *o; o++) {
321 if ((*o)->option == option && (*o)->ack == cmd) {
322 switch (telnet->opt_states[(*o)->index]) {
324 telnet->opt_states[(*o)->index] = ACTIVE;
325 activate_option(telnet, *o);
330 telnet->opt_states[(*o)->index] = ACTIVE;
331 send_opt(telnet, (*o)->send, option);
332 activate_option(telnet, *o);
334 case REALLY_INACTIVE:
335 send_opt(telnet, (*o)->nsend, option);
339 } else if ((*o)->option == option && (*o)->nak == cmd) {
340 switch (telnet->opt_states[(*o)->index]) {
342 telnet->opt_states[(*o)->index] = INACTIVE;
343 refused_option(telnet, *o);
346 telnet->opt_states[(*o)->index] = INACTIVE;
347 send_opt(telnet, (*o)->nsend, option);
348 option_side_effects(telnet, *o, 0);
351 case REALLY_INACTIVE:
358 * If we reach here, the option was one we weren't prepared to
359 * cope with. If the request was positive (WILL or DO), we send
360 * a negative ack to indicate refusal. If the request was
361 * negative (WONT / DONT), we must do nothing.
363 if (cmd == WILL || cmd == DO)
364 send_opt(telnet, (cmd == WILL ? DONT : WONT), option);
367 static void process_subneg(Telnet telnet)
369 unsigned char *b, *p, *q;
370 int var, value, n, bsize;
371 char *e, *eval, *ekey, *user;
373 switch (telnet->sb_opt) {
375 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
377 char *termspeed = conf_get_str(telnet->conf, CONF_termspeed);
378 b = snewn(20 + strlen(termspeed), unsigned char);
381 b[2] = TELOPT_TSPEED;
383 strcpy((char *)(b + 4), termspeed);
384 n = 4 + strlen(termspeed);
387 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 2);
388 logevent(telnet->frontend, "server:\tSB TSPEED SEND");
389 logbuf = dupprintf("client:\tSB TSPEED IS %s", termspeed);
390 logevent(telnet->frontend, logbuf);
394 logevent(telnet->frontend, "server:\tSB TSPEED <something weird>");
397 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
399 char *termtype = conf_get_str(telnet->conf, CONF_termtype);
400 b = snewn(20 + strlen(termtype), unsigned char);
405 for (n = 0; termtype[n]; n++)
406 b[n + 4] = (termtype[n] >= 'a' && termtype[n] <= 'z' ?
407 termtype[n] + 'A' - 'a' :
411 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 6);
413 logevent(telnet->frontend, "server:\tSB TTYPE SEND");
414 logbuf = dupprintf("client:\tSB TTYPE IS %s", b + 4);
415 logevent(telnet->frontend, logbuf);
419 logevent(telnet->frontend, "server:\tSB TTYPE <something weird>\r\n");
421 case TELOPT_OLD_ENVIRON:
422 case TELOPT_NEW_ENVIRON:
424 q = p + telnet->sb_len;
425 if (p < q && *p == TELQUAL_SEND) {
428 logbuf = dupprintf("server:\tSB %s SEND", telopt(telnet->sb_opt));
429 logevent(telnet->frontend, logbuf);
431 if (telnet->sb_opt == TELOPT_OLD_ENVIRON) {
432 if (conf_get_int(telnet->conf, CONF_rfc_environ)) {
440 * Try to guess the sense of VAR and VALUE.
446 } else if (*p == BSD_VAR) {
454 * With NEW_ENVIRON, the sense of VAR and VALUE
461 for (eval = conf_get_str_strs(telnet->conf, CONF_environmt,
464 eval = conf_get_str_strs(telnet->conf, CONF_environmt,
466 bsize += strlen(ekey) + strlen(eval) + 2;
467 user = get_remote_username(telnet->conf);
469 bsize += 6 + strlen(user);
471 b = snewn(bsize, unsigned char);
474 b[2] = telnet->sb_opt;
477 for (eval = conf_get_str_strs(telnet->conf, CONF_environmt,
480 eval = conf_get_str_strs(telnet->conf, CONF_environmt,
483 for (e = ekey; *e; e++)
486 for (e = eval; *e; e++)
496 for (e = user; *e; e++)
501 telnet->bufsize = sk_write(telnet->s, (char *)b, n);
503 logbuf = dupprintf("client:\tSB %s IS <nothing>",
504 telopt(telnet->sb_opt));
505 logevent(telnet->frontend, logbuf);
508 logbuf = dupprintf("client:\tSB %s IS:",
509 telopt(telnet->sb_opt));
510 logevent(telnet->frontend, logbuf);
512 for (eval = conf_get_str_strs(telnet->conf, CONF_environmt,
515 eval = conf_get_str_strs(telnet->conf, CONF_environmt,
517 logbuf = dupprintf("\t%s=%s", ekey, eval);
518 logevent(telnet->frontend, logbuf);
522 logbuf = dupprintf("\tUSER=%s", user);
523 logevent(telnet->frontend, logbuf);
534 static void do_telnet_read(Telnet telnet, char *buf, int len)
537 int outbuflen = 0, outbufsize = 0;
539 #define ADDTOBUF(c) do { \
540 if (outbuflen >= outbufsize) { \
541 outbufsize = outbuflen + 256; \
542 outbuf = sresize(outbuf, outbufsize, char); \
544 outbuf[outbuflen++] = (c); \
548 int c = (unsigned char) *buf++;
550 switch (telnet->state) {
553 if (c == NUL && telnet->state == SEENCR)
554 telnet->state = TOP_LEVEL;
556 telnet->state = SEENIAC;
558 if (!telnet->in_synch)
562 /* I can't get the F***ing winsock to insert the urgent IAC
563 * into the right position! Even with SO_OOBINLINE it gives
564 * it to recv too soon. And of course the DM byte (that
565 * arrives in the same packet!) appears several K later!!
567 * Oh well, we do get the DM in the right place so I'll
568 * just stop hiding on the next 0xf2 and hope for the best.
571 telnet->in_synch = 0;
573 if (c == CR && telnet->opt_states[o_they_bin.index] != ACTIVE)
574 telnet->state = SEENCR;
576 telnet->state = TOP_LEVEL;
581 telnet->state = SEENDO;
583 telnet->state = SEENDONT;
585 telnet->state = SEENWILL;
587 telnet->state = SEENWONT;
589 telnet->state = SEENSB;
591 telnet->in_synch = 0;
592 telnet->state = TOP_LEVEL;
594 /* ignore everything else; print it if it's IAC */
598 telnet->state = TOP_LEVEL;
602 proc_rec_opt(telnet, WILL, c);
603 telnet->state = TOP_LEVEL;
606 proc_rec_opt(telnet, WONT, c);
607 telnet->state = TOP_LEVEL;
610 proc_rec_opt(telnet, DO, c);
611 telnet->state = TOP_LEVEL;
614 proc_rec_opt(telnet, DONT, c);
615 telnet->state = TOP_LEVEL;
620 telnet->state = SUBNEGOT;
624 telnet->state = SUBNEG_IAC;
627 if (telnet->sb_len >= telnet->sb_size) {
628 telnet->sb_size += SB_DELTA;
629 telnet->sb_buf = sresize(telnet->sb_buf, telnet->sb_size,
632 telnet->sb_buf[telnet->sb_len++] = c;
633 telnet->state = SUBNEGOT; /* in case we came here by goto */
638 goto subneg_addchar; /* yes, it's a hack, I know, but... */
640 process_subneg(telnet);
641 telnet->state = TOP_LEVEL;
648 c_write(telnet, outbuf, outbuflen);
652 static void telnet_log(Plug plug, int type, SockAddr addr, int port,
653 const char *error_msg, int error_code)
655 Telnet telnet = (Telnet) plug;
656 backend_socket_log(telnet->frontend, type, addr, port,
657 error_msg, error_code, telnet->conf,
658 telnet->session_started);
661 static int telnet_closing(Plug plug, const char *error_msg, int error_code,
664 Telnet telnet = (Telnet) plug;
667 * We don't implement independent EOF in each direction for Telnet
668 * connections; as soon as we get word that the remote side has
669 * sent us EOF, we wind up the whole connection.
676 telnet->closed_on_socket_error = TRUE;
677 notify_remote_exit(telnet->frontend);
680 logevent(telnet->frontend, error_msg);
681 connection_fatal(telnet->frontend, "%s", error_msg);
683 /* Otherwise, the remote side closed the connection normally. */
687 static int telnet_receive(Plug plug, int urgent, char *data, int len)
689 Telnet telnet = (Telnet) plug;
691 telnet->in_synch = TRUE;
692 telnet->session_started = TRUE;
693 do_telnet_read(telnet, data, len);
697 static void telnet_sent(Plug plug, int bufsize)
699 Telnet telnet = (Telnet) plug;
700 telnet->bufsize = bufsize;
704 * Called to set up the Telnet connection.
706 * Returns an error message, or NULL on success.
708 * Also places the canonical host name into `realhost'. It must be
709 * freed by the caller.
711 static const char *telnet_init(void *frontend_handle, void **backend_handle,
712 Conf *conf, const char *host, int port,
713 char **realhost, int nodelay, int keepalive)
715 static const struct plug_function_table fn_table = {
727 telnet = snew(struct telnet_tag);
728 telnet->fn = &fn_table;
729 telnet->conf = conf_copy(conf);
731 telnet->closed_on_socket_error = FALSE;
732 telnet->echoing = TRUE;
733 telnet->editing = TRUE;
734 telnet->activated = FALSE;
735 telnet->sb_buf = NULL;
737 telnet->frontend = frontend_handle;
738 telnet->term_width = conf_get_int(telnet->conf, CONF_width);
739 telnet->term_height = conf_get_int(telnet->conf, CONF_height);
740 telnet->state = TOP_LEVEL;
741 telnet->ldisc = NULL;
742 telnet->pinger = NULL;
743 telnet->session_started = TRUE;
744 *backend_handle = telnet;
749 addressfamily = conf_get_int(telnet->conf, CONF_addressfamily);
750 addr = name_lookup(host, port, realhost, telnet->conf, addressfamily,
751 telnet->frontend, "Telnet connection");
752 if ((err = sk_addr_error(addr)) != NULL) {
758 port = 23; /* default telnet port */
763 telnet->s = new_connection(addr, *realhost, port, 0, 1,
764 nodelay, keepalive, (Plug) telnet, telnet->conf);
765 if ((err = sk_socket_error(telnet->s)) != NULL)
768 telnet->pinger = pinger_new(telnet->conf, &telnet_backend, telnet);
771 * Initialise option states.
773 if (conf_get_int(telnet->conf, CONF_passive_telnet)) {
774 const struct Opt *const *o;
776 for (o = opts; *o; o++)
777 telnet->opt_states[(*o)->index] = INACTIVE;
779 const struct Opt *const *o;
781 for (o = opts; *o; o++) {
782 telnet->opt_states[(*o)->index] = (*o)->initial_state;
783 if (telnet->opt_states[(*o)->index] == REQUESTED)
784 send_opt(telnet, (*o)->send, (*o)->option);
786 telnet->activated = TRUE;
790 * Set up SYNCH state.
792 telnet->in_synch = FALSE;
795 * We can send special commands from the start.
797 update_specials_menu(telnet->frontend);
800 * loghost overrides realhost, if specified.
802 loghost = conf_get_str(telnet->conf, CONF_loghost);
807 *realhost = dupstr(loghost);
809 colon = host_strrchr(*realhost, ':');
817 static void telnet_free(void *handle)
819 Telnet telnet = (Telnet) handle;
821 sfree(telnet->sb_buf);
825 pinger_free(telnet->pinger);
826 conf_free(telnet->conf);
830 * Reconfigure the Telnet backend. There's no immediate action
831 * necessary, in this backend: we just save the fresh config for
832 * any subsequent negotiations.
834 static void telnet_reconfig(void *handle, Conf *conf)
836 Telnet telnet = (Telnet) handle;
837 pinger_reconfig(telnet->pinger, telnet->conf, conf);
838 conf_free(telnet->conf);
839 telnet->conf = conf_copy(conf);
843 * Called to send data down the Telnet connection.
845 static int telnet_send(void *handle, const char *buf, int len)
847 Telnet telnet = (Telnet) handle;
848 unsigned char *p, *end;
849 static const unsigned char iac[2] = { IAC, IAC };
850 static const unsigned char cr[2] = { CR, NUL };
852 static const unsigned char nl[2] = { CR, LF };
855 if (telnet->s == NULL)
858 p = (unsigned char *)buf;
859 end = (unsigned char *)(buf + len);
861 unsigned char *q = p;
863 while (p < end && iswritable(*p))
865 telnet->bufsize = sk_write(telnet->s, (char *)q, p - q);
867 while (p < end && !iswritable(*p)) {
869 sk_write(telnet->s, (char *)(*p == IAC ? iac : cr), 2);
874 return telnet->bufsize;
878 * Called to query the current socket sendability status.
880 static int telnet_sendbuffer(void *handle)
882 Telnet telnet = (Telnet) handle;
883 return telnet->bufsize;
887 * Called to set the size of the window from Telnet's POV.
889 static void telnet_size(void *handle, int width, int height)
891 Telnet telnet = (Telnet) handle;
896 telnet->term_width = width;
897 telnet->term_height = height;
899 if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)
904 b[n++] = TELOPT_NAWS;
905 b[n++] = telnet->term_width >> 8;
906 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
907 b[n++] = telnet->term_width & 0xFF;
908 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
909 b[n++] = telnet->term_height >> 8;
910 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
911 b[n++] = telnet->term_height & 0xFF;
912 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
915 telnet->bufsize = sk_write(telnet->s, (char *)b, n);
916 logbuf = dupprintf("client:\tSB NAWS %d,%d",
917 telnet->term_width, telnet->term_height);
918 logevent(telnet->frontend, logbuf);
923 * Send Telnet special codes.
925 static void telnet_special(void *handle, Telnet_Special code)
927 Telnet telnet = (Telnet) handle;
930 if (telnet->s == NULL)
937 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
941 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
945 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
949 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
953 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
957 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
961 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
965 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
969 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
973 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
977 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
981 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
984 /* In BINARY mode, CR-LF becomes just CR -
985 * and without the NUL suffix too. */
986 if (telnet->opt_states[o_we_bin.index] == ACTIVE)
987 telnet->bufsize = sk_write(telnet->s, "\r", 1);
989 telnet->bufsize = sk_write(telnet->s, "\r\n", 2);
993 telnet->bufsize = sk_write(telnet->s, (char *)b, 1);
994 telnet->bufsize = sk_write_oob(telnet->s, (char *)(b + 1), 1);
997 if (telnet->opt_states[o_echo.index] == INACTIVE ||
998 telnet->opt_states[o_echo.index] == REALLY_INACTIVE) {
999 telnet->opt_states[o_echo.index] = REQUESTED;
1000 send_opt(telnet, o_echo.send, o_echo.option);
1004 if (telnet->opt_states[o_echo.index] == ACTIVE) {
1005 telnet->opt_states[o_echo.index] = REQUESTED;
1006 send_opt(telnet, o_echo.nsend, o_echo.option);
1010 if (telnet->opt_states[o_they_sga.index] == ACTIVE) {
1012 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
1016 break; /* never heard of it */
1020 static const struct telnet_special *telnet_get_specials(void *handle)
1022 static const struct telnet_special specials[] = {
1023 {"Are You There", TS_AYT},
1025 {"Synch", TS_SYNCH},
1026 {"Erase Character", TS_EC},
1027 {"Erase Line", TS_EL},
1028 {"Go Ahead", TS_GA},
1029 {"No Operation", TS_NOP},
1031 {"Abort Process", TS_ABORT},
1032 {"Abort Output", TS_AO},
1033 {"Interrupt Process", TS_IP},
1034 {"Suspend Process", TS_SUSP},
1036 {"End Of Record", TS_EOR},
1037 {"End Of File", TS_EOF},
1043 static int telnet_connected(void *handle)
1045 Telnet telnet = (Telnet) handle;
1046 return telnet->s != NULL;
1049 static int telnet_sendok(void *handle)
1051 /* Telnet telnet = (Telnet) handle; */
1055 static void telnet_unthrottle(void *handle, int backlog)
1057 Telnet telnet = (Telnet) handle;
1058 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
1061 static int telnet_ldisc(void *handle, int option)
1063 Telnet telnet = (Telnet) handle;
1064 if (option == LD_ECHO)
1065 return telnet->echoing;
1066 if (option == LD_EDIT)
1067 return telnet->editing;
1071 static void telnet_provide_ldisc(void *handle, void *ldisc)
1073 Telnet telnet = (Telnet) handle;
1074 telnet->ldisc = ldisc;
1077 static void telnet_provide_logctx(void *handle, void *logctx)
1079 /* This is a stub. */
1082 static int telnet_exitcode(void *handle)
1084 Telnet telnet = (Telnet) handle;
1085 if (telnet->s != NULL)
1086 return -1; /* still connected */
1087 else if (telnet->closed_on_socket_error)
1088 return INT_MAX; /* a socket error counts as an unclean exit */
1090 /* Telnet doesn't transmit exit codes back to the client */
1095 * cfg_info for Telnet does nothing at all.
1097 static int telnet_cfg_info(void *handle)
1102 Backend telnet_backend = {
1110 telnet_get_specials,
1115 telnet_provide_ldisc,
1116 telnet_provide_logctx,
1119 NULL /* test_for_upstream */,