17 #define IAC 255 /* interpret as command: */
18 #define DONT 254 /* you are not to use option */
19 #define DO 253 /* please, you use option */
20 #define WONT 252 /* I won't use option */
21 #define WILL 251 /* I will use option */
22 #define SB 250 /* interpret as subnegotiation */
23 #define SE 240 /* end sub negotiation */
25 #define GA 249 /* you may reverse the line */
26 #define EL 248 /* erase the current line */
27 #define EC 247 /* erase the current character */
28 #define AYT 246 /* are you there */
29 #define AO 245 /* abort output--but let prog finish */
30 #define IP 244 /* interrupt process--permanently */
31 #define BREAK 243 /* break */
32 #define DM 242 /* data mark--for connect. cleaning */
33 #define NOP 241 /* nop */
34 #define EOR 239 /* end of record (transparent mode) */
35 #define ABORT 238 /* Abort process */
36 #define SUSP 237 /* Suspend process */
37 #define xEOF 236 /* End of file: EOF is already used... */
40 X(BINARY, 0) /* 8-bit data path */ \
41 X(ECHO, 1) /* echo */ \
42 X(RCP, 2) /* prepare to reconnect */ \
43 X(SGA, 3) /* suppress go ahead */ \
44 X(NAMS, 4) /* approximate message size */ \
45 X(STATUS, 5) /* give status */ \
46 X(TM, 6) /* timing mark */ \
47 X(RCTE, 7) /* remote controlled transmission and echo */ \
48 X(NAOL, 8) /* negotiate about output line width */ \
49 X(NAOP, 9) /* negotiate about output page size */ \
50 X(NAOCRD, 10) /* negotiate about CR disposition */ \
51 X(NAOHTS, 11) /* negotiate about horizontal tabstops */ \
52 X(NAOHTD, 12) /* negotiate about horizontal tab disposition */ \
53 X(NAOFFD, 13) /* negotiate about formfeed disposition */ \
54 X(NAOVTS, 14) /* negotiate about vertical tab stops */ \
55 X(NAOVTD, 15) /* negotiate about vertical tab disposition */ \
56 X(NAOLFD, 16) /* negotiate about output LF disposition */ \
57 X(XASCII, 17) /* extended ascic character set */ \
58 X(LOGOUT, 18) /* force logout */ \
59 X(BM, 19) /* byte macro */ \
60 X(DET, 20) /* data entry terminal */ \
61 X(SUPDUP, 21) /* supdup protocol */ \
62 X(SUPDUPOUTPUT, 22) /* supdup output */ \
63 X(SNDLOC, 23) /* send location */ \
64 X(TTYPE, 24) /* terminal type */ \
65 X(EOR, 25) /* end or record */ \
66 X(TUID, 26) /* TACACS user identification */ \
67 X(OUTMRK, 27) /* output marking */ \
68 X(TTYLOC, 28) /* terminal location number */ \
69 X(3270REGIME, 29) /* 3270 regime */ \
70 X(X3PAD, 30) /* X.3 PAD */ \
71 X(NAWS, 31) /* window size */ \
72 X(TSPEED, 32) /* terminal speed */ \
73 X(LFLOW, 33) /* remote flow control */ \
74 X(LINEMODE, 34) /* Linemode option */ \
75 X(XDISPLOC, 35) /* X Display Location */ \
76 X(OLD_ENVIRON, 36) /* Old - Environment variables */ \
77 X(AUTHENTICATION, 37) /* Authenticate */ \
78 X(ENCRYPT, 38) /* Encryption option */ \
79 X(NEW_ENVIRON, 39) /* New - Environment variables */ \
80 X(TN3270E, 40) /* TN3270 enhancements */ \
82 X(CHARSET, 42) /* Character set */ \
83 X(RSP, 43) /* Remote serial port */ \
84 X(COM_PORT_OPTION, 44) /* Com port control */ \
85 X(SLE, 45) /* Suppress local echo */ \
86 X(STARTTLS, 46) /* Start TLS */ \
87 X(KERMIT, 47) /* Automatic Kermit file transfer */ \
90 X(PRAGMA_LOGON, 138) \
92 X(PRAGMA_HEARTBEAT, 140) \
93 X(EXOPL, 255) /* extended-options-list */
95 #define telnet_enum(x,y) TELOPT_##x = y,
96 enum { TELOPTS(telnet_enum) dummy=0 };
99 #define TELQUAL_IS 0 /* option is... */
100 #define TELQUAL_SEND 1 /* send option */
101 #define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
111 #define iswritable(x) \
113 (telnet->opt_states[o_we_bin.index] == ACTIVE || (x) != CR))
115 static char *telopt(int opt)
117 #define telnet_str(x,y) case TELOPT_##x: return #x;
126 static void telnet_size(void *handle, int width, int height);
129 int send; /* what we initially send */
130 int nsend; /* -ve send if requested to stop it */
131 int ack, nak; /* +ve and -ve acknowledgements */
132 int option; /* the option code */
133 int index; /* index into telnet->opt_states[] */
135 REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE
153 static const struct Opt o_naws =
154 { WILL, WONT, DO, DONT, TELOPT_NAWS, OPTINDEX_NAWS, REQUESTED };
155 static const struct Opt o_tspeed =
156 { WILL, WONT, DO, DONT, TELOPT_TSPEED, OPTINDEX_TSPEED, REQUESTED };
157 static const struct Opt o_ttype =
158 { WILL, WONT, DO, DONT, TELOPT_TTYPE, OPTINDEX_TTYPE, REQUESTED };
159 static const struct Opt o_oenv =
160 { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON, OPTINDEX_OENV, INACTIVE };
161 static const struct Opt o_nenv =
162 { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON, OPTINDEX_NENV, REQUESTED };
163 static const struct Opt o_echo =
164 { DO, DONT, WILL, WONT, TELOPT_ECHO, OPTINDEX_ECHO, REQUESTED };
165 static const struct Opt o_we_sga =
166 { WILL, WONT, DO, DONT, TELOPT_SGA, OPTINDEX_WE_SGA, REQUESTED };
167 static const struct Opt o_they_sga =
168 { DO, DONT, WILL, WONT, TELOPT_SGA, OPTINDEX_THEY_SGA, REQUESTED };
169 static const struct Opt o_we_bin =
170 { WILL, WONT, DO, DONT, TELOPT_BINARY, OPTINDEX_WE_BIN, INACTIVE };
171 static const struct Opt o_they_bin =
172 { DO, DONT, WILL, WONT, TELOPT_BINARY, OPTINDEX_THEY_BIN, INACTIVE };
174 static const struct Opt *const opts[] = {
175 &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,
176 &o_we_sga, &o_they_sga, &o_we_bin, &o_they_bin, NULL
179 typedef struct telnet_tag {
180 const struct plug_function_table *fn;
181 /* the above field _must_ be first in the structure */
187 int term_width, term_height;
189 int opt_states[NUM_OPTS];
191 int echoing, editing;
196 unsigned char *sb_buf;
200 TOP_LEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
201 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
209 #define TELNET_MAX_BACKLOG 4096
211 #define SB_DELTA 1024
213 static void c_write(Telnet telnet, char *buf, int len)
216 backlog = from_backend(telnet->frontend, 0, buf, len);
217 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
220 static void log_option(Telnet telnet, char *sender, int cmd, int option)
224 * The strange-looking "<?""?>" below is there to avoid a
225 * trigraph - a double question mark followed by > maps to a
226 * closing brace character!
228 buf = dupprintf("%s:\t%s %s", sender,
229 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
230 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<?""?>"),
232 logevent(telnet->frontend, buf);
236 static void send_opt(Telnet telnet, int cmd, int option)
243 telnet->bufsize = sk_write(telnet->s, (char *)b, 3);
244 log_option(telnet, "client", cmd, option);
247 static void deactivate_option(Telnet telnet, const struct Opt *o)
249 if (telnet->opt_states[o->index] == REQUESTED ||
250 telnet->opt_states[o->index] == ACTIVE)
251 send_opt(telnet, o->nsend, o->option);
252 telnet->opt_states[o->index] = REALLY_INACTIVE;
256 * Generate side effects of enabling or disabling an option.
258 static void option_side_effects(Telnet telnet, const struct Opt *o, int enabled)
260 if (o->option == TELOPT_ECHO && o->send == DO)
261 telnet->echoing = !enabled;
262 else if (o->option == TELOPT_SGA && o->send == DO)
263 telnet->editing = !enabled;
264 if (telnet->ldisc) /* cause ldisc to notice the change */
265 ldisc_send(telnet->ldisc, NULL, 0, 0);
267 /* Ensure we get the minimum options */
268 if (!telnet->activated) {
269 if (telnet->opt_states[o_echo.index] == INACTIVE) {
270 telnet->opt_states[o_echo.index] = REQUESTED;
271 send_opt(telnet, o_echo.send, o_echo.option);
273 if (telnet->opt_states[o_we_sga.index] == INACTIVE) {
274 telnet->opt_states[o_we_sga.index] = REQUESTED;
275 send_opt(telnet, o_we_sga.send, o_we_sga.option);
277 if (telnet->opt_states[o_they_sga.index] == INACTIVE) {
278 telnet->opt_states[o_they_sga.index] = REQUESTED;
279 send_opt(telnet, o_they_sga.send, o_they_sga.option);
281 telnet->activated = TRUE;
285 static void activate_option(Telnet telnet, const struct Opt *o)
287 if (o->send == WILL && o->option == TELOPT_NAWS)
288 telnet_size(telnet, telnet->term_width, telnet->term_height);
289 if (o->send == WILL &&
290 (o->option == TELOPT_NEW_ENVIRON ||
291 o->option == TELOPT_OLD_ENVIRON)) {
293 * We may only have one kind of ENVIRON going at a time.
294 * This is a hack, but who cares.
296 deactivate_option(telnet, o->option ==
297 TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
299 option_side_effects(telnet, o, 1);
302 static void refused_option(Telnet telnet, const struct Opt *o)
304 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
305 telnet->opt_states[o_oenv.index] == INACTIVE) {
306 send_opt(telnet, WILL, TELOPT_OLD_ENVIRON);
307 telnet->opt_states[o_oenv.index] = REQUESTED;
309 option_side_effects(telnet, o, 0);
312 static void proc_rec_opt(Telnet telnet, int cmd, int option)
314 const struct Opt *const *o;
316 log_option(telnet, "server", cmd, option);
317 for (o = opts; *o; o++) {
318 if ((*o)->option == option && (*o)->ack == cmd) {
319 switch (telnet->opt_states[(*o)->index]) {
321 telnet->opt_states[(*o)->index] = ACTIVE;
322 activate_option(telnet, *o);
327 telnet->opt_states[(*o)->index] = ACTIVE;
328 send_opt(telnet, (*o)->send, option);
329 activate_option(telnet, *o);
331 case REALLY_INACTIVE:
332 send_opt(telnet, (*o)->nsend, option);
336 } else if ((*o)->option == option && (*o)->nak == cmd) {
337 switch (telnet->opt_states[(*o)->index]) {
339 telnet->opt_states[(*o)->index] = INACTIVE;
340 refused_option(telnet, *o);
343 telnet->opt_states[(*o)->index] = INACTIVE;
344 send_opt(telnet, (*o)->nsend, option);
345 option_side_effects(telnet, *o, 0);
348 case REALLY_INACTIVE:
355 * If we reach here, the option was one we weren't prepared to
356 * cope with. If the request was positive (WILL or DO), we send
357 * a negative ack to indicate refusal. If the request was
358 * negative (WONT / DONT), we must do nothing.
360 if (cmd == WILL || cmd == DO)
361 send_opt(telnet, (cmd == WILL ? DONT : WONT), option);
364 static void process_subneg(Telnet telnet)
366 unsigned char b[2048], *p, *q;
370 switch (telnet->sb_opt) {
372 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
376 b[2] = TELOPT_TSPEED;
378 strcpy((char *)(b + 4), telnet->cfg.termspeed);
379 n = 4 + strlen(telnet->cfg.termspeed);
382 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 2);
383 logevent(telnet->frontend, "server:\tSB TSPEED SEND");
384 logbuf = dupprintf("client:\tSB TSPEED IS %s", telnet->cfg.termspeed);
385 logevent(telnet->frontend, logbuf);
388 logevent(telnet->frontend, "server:\tSB TSPEED <something weird>");
391 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
397 for (n = 0; telnet->cfg.termtype[n]; n++)
398 b[n + 4] = (telnet->cfg.termtype[n] >= 'a'
399 && telnet->cfg.termtype[n] <=
400 'z' ? telnet->cfg.termtype[n] + 'A' -
401 'a' : telnet->cfg.termtype[n]);
404 telnet->bufsize = sk_write(telnet->s, (char *)b, n + 6);
406 logevent(telnet->frontend, "server:\tSB TTYPE SEND");
407 logbuf = dupprintf("client:\tSB TTYPE IS %s", b + 4);
408 logevent(telnet->frontend, logbuf);
411 logevent(telnet->frontend, "server:\tSB TTYPE <something weird>\r\n");
413 case TELOPT_OLD_ENVIRON:
414 case TELOPT_NEW_ENVIRON:
416 q = p + telnet->sb_len;
417 if (p < q && *p == TELQUAL_SEND) {
420 logbuf = dupprintf("server:\tSB %s SEND", telopt(telnet->sb_opt));
421 logevent(telnet->frontend, logbuf);
423 if (telnet->sb_opt == TELOPT_OLD_ENVIRON) {
424 if (telnet->cfg.rfc_environ) {
432 * Try to guess the sense of VAR and VALUE.
438 } else if (*p == BSD_VAR) {
446 * With NEW_ENVIRON, the sense of VAR and VALUE
454 b[2] = telnet->sb_opt;
457 e = telnet->cfg.environmt;
460 while (*e && *e != '\t')
469 if (*telnet->cfg.username) {
476 e = telnet->cfg.username;
482 telnet->bufsize = sk_write(telnet->s, (char *)b, n);
483 logbuf = dupprintf("client:\tSB %s IS %s%s%s%s",
484 telopt(telnet->sb_opt),
485 *telnet->cfg.username ? "USER=" : "",
486 telnet->cfg.username,
487 *telnet->cfg.username ? " " : "",
488 n == 6 ? "<nothing>" :
489 (*telnet->cfg.environmt ? "<stuff>" : ""));
490 logevent(telnet->frontend, logbuf);
497 static void do_telnet_read(Telnet telnet, char *buf, int len)
500 int outbuflen = 0, outbufsize = 0;
502 #define ADDTOBUF(c) do { \
503 if (outbuflen >= outbufsize) { \
504 outbufsize = outbuflen + 256; \
505 outbuf = sresize(outbuf, outbufsize, char); \
507 outbuf[outbuflen++] = (c); \
511 int c = (unsigned char) *buf++;
513 switch (telnet->state) {
516 if (c == NUL && telnet->state == SEENCR)
517 telnet->state = TOP_LEVEL;
519 telnet->state = SEENIAC;
521 if (!telnet->in_synch)
525 /* I can't get the F***ing winsock to insert the urgent IAC
526 * into the right position! Even with SO_OOBINLINE it gives
527 * it to recv too soon. And of course the DM byte (that
528 * arrives in the same packet!) appears several K later!!
530 * Oh well, we do get the DM in the right place so I'll
531 * just stop hiding on the next 0xf2 and hope for the best.
534 telnet->in_synch = 0;
536 if (c == CR && telnet->opt_states[o_they_bin.index] != ACTIVE)
537 telnet->state = SEENCR;
539 telnet->state = TOP_LEVEL;
544 telnet->state = SEENDO;
546 telnet->state = SEENDONT;
548 telnet->state = SEENWILL;
550 telnet->state = SEENWONT;
552 telnet->state = SEENSB;
554 telnet->in_synch = 0;
555 telnet->state = TOP_LEVEL;
557 /* ignore everything else; print it if it's IAC */
561 telnet->state = TOP_LEVEL;
565 proc_rec_opt(telnet, WILL, c);
566 telnet->state = TOP_LEVEL;
569 proc_rec_opt(telnet, WONT, c);
570 telnet->state = TOP_LEVEL;
573 proc_rec_opt(telnet, DO, c);
574 telnet->state = TOP_LEVEL;
577 proc_rec_opt(telnet, DONT, c);
578 telnet->state = TOP_LEVEL;
583 telnet->state = SUBNEGOT;
587 telnet->state = SUBNEG_IAC;
590 if (telnet->sb_len >= telnet->sb_size) {
591 telnet->sb_size += SB_DELTA;
592 telnet->sb_buf = sresize(telnet->sb_buf, telnet->sb_size,
595 telnet->sb_buf[telnet->sb_len++] = c;
596 telnet->state = SUBNEGOT; /* in case we came here by goto */
601 goto subneg_addchar; /* yes, it's a hack, I know, but... */
603 process_subneg(telnet);
604 telnet->state = TOP_LEVEL;
611 c_write(telnet, outbuf, outbuflen);
615 static void telnet_log(Plug plug, int type, SockAddr addr, int port,
616 const char *error_msg, int error_code)
618 Telnet telnet = (Telnet) plug;
619 char addrbuf[256], *msg;
621 sk_getaddr(addr, addrbuf, lenof(addrbuf));
624 msg = dupprintf("Connecting to %s port %d", addrbuf, port);
626 msg = dupprintf("Failed to connect to %s: %s", addrbuf, error_msg);
628 logevent(telnet->frontend, msg);
631 static int telnet_closing(Plug plug, const char *error_msg, int error_code,
634 Telnet telnet = (Telnet) plug;
639 notify_remote_exit(telnet->frontend);
642 logevent(telnet->frontend, error_msg);
643 connection_fatal(telnet->frontend, "%s", error_msg);
645 /* Otherwise, the remote side closed the connection normally. */
649 static int telnet_receive(Plug plug, int urgent, char *data, int len)
651 Telnet telnet = (Telnet) plug;
653 telnet->in_synch = TRUE;
654 do_telnet_read(telnet, data, len);
658 static void telnet_sent(Plug plug, int bufsize)
660 Telnet telnet = (Telnet) plug;
661 telnet->bufsize = bufsize;
665 * Called to set up the Telnet connection.
667 * Returns an error message, or NULL on success.
669 * Also places the canonical host name into `realhost'. It must be
670 * freed by the caller.
672 static const char *telnet_init(void *frontend_handle, void **backend_handle,
674 char *host, int port, char **realhost,
675 int nodelay, int keepalive)
677 static const struct plug_function_table fn_table = {
687 telnet = snew(struct telnet_tag);
688 telnet->fn = &fn_table;
689 telnet->cfg = *cfg; /* STRUCTURE COPY */
691 telnet->echoing = TRUE;
692 telnet->editing = TRUE;
693 telnet->activated = FALSE;
694 telnet->sb_buf = NULL;
696 telnet->frontend = frontend_handle;
697 telnet->term_width = telnet->cfg.width;
698 telnet->term_height = telnet->cfg.height;
699 telnet->state = TOP_LEVEL;
700 telnet->ldisc = NULL;
701 telnet->pinger = NULL;
702 *backend_handle = telnet;
709 buf = dupprintf("Looking up host \"%s\"%s", host,
710 (cfg->addressfamily == ADDRTYPE_IPV4 ? " (IPv4)" :
711 (cfg->addressfamily == ADDRTYPE_IPV6 ? " (IPv6)" :
713 logevent(telnet->frontend, buf);
716 addr = name_lookup(host, port, realhost, &telnet->cfg, cfg->addressfamily);
717 if ((err = sk_addr_error(addr)) != NULL) {
723 port = 23; /* default telnet port */
728 telnet->s = new_connection(addr, *realhost, port, 0, 1,
729 nodelay, keepalive, (Plug) telnet, &telnet->cfg);
730 if ((err = sk_socket_error(telnet->s)) != NULL)
733 telnet->pinger = pinger_new(&telnet->cfg, &telnet_backend, telnet);
736 * Initialise option states.
738 if (telnet->cfg.passive_telnet) {
739 const struct Opt *const *o;
741 for (o = opts; *o; o++)
742 telnet->opt_states[(*o)->index] = INACTIVE;
744 const struct Opt *const *o;
746 for (o = opts; *o; o++) {
747 telnet->opt_states[(*o)->index] = (*o)->initial_state;
748 if (telnet->opt_states[(*o)->index] == REQUESTED)
749 send_opt(telnet, (*o)->send, (*o)->option);
751 telnet->activated = TRUE;
755 * Set up SYNCH state.
757 telnet->in_synch = FALSE;
760 * We can send special commands from the start.
762 update_specials_menu(telnet->frontend);
765 * loghost overrides realhost, if specified.
767 if (*telnet->cfg.loghost) {
771 *realhost = dupstr(telnet->cfg.loghost);
772 colon = strrchr(*realhost, ':');
775 * FIXME: if we ever update this aspect of ssh.c for
776 * IPv6 literal management, this should change in line
786 static void telnet_free(void *handle)
788 Telnet telnet = (Telnet) handle;
790 sfree(telnet->sb_buf);
794 pinger_free(telnet->pinger);
798 * Reconfigure the Telnet backend. There's no immediate action
799 * necessary, in this backend: we just save the fresh config for
800 * any subsequent negotiations.
802 static void telnet_reconfig(void *handle, Config *cfg)
804 Telnet telnet = (Telnet) handle;
805 pinger_reconfig(telnet->pinger, &telnet->cfg, cfg);
806 telnet->cfg = *cfg; /* STRUCTURE COPY */
810 * Called to send data down the Telnet connection.
812 static int telnet_send(void *handle, char *buf, int len)
814 Telnet telnet = (Telnet) handle;
815 unsigned char *p, *end;
816 static const unsigned char iac[2] = { IAC, IAC };
817 static const unsigned char cr[2] = { CR, NUL };
819 static const unsigned char nl[2] = { CR, LF };
822 if (telnet->s == NULL)
825 p = (unsigned char *)buf;
826 end = (unsigned char *)(buf + len);
828 unsigned char *q = p;
830 while (p < end && iswritable(*p))
832 telnet->bufsize = sk_write(telnet->s, (char *)q, p - q);
834 while (p < end && !iswritable(*p)) {
836 sk_write(telnet->s, (char *)(*p == IAC ? iac : cr), 2);
841 return telnet->bufsize;
845 * Called to query the current socket sendability status.
847 static int telnet_sendbuffer(void *handle)
849 Telnet telnet = (Telnet) handle;
850 return telnet->bufsize;
854 * Called to set the size of the window from Telnet's POV.
856 static void telnet_size(void *handle, int width, int height)
858 Telnet telnet = (Telnet) handle;
863 telnet->term_width = width;
864 telnet->term_height = height;
866 if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)
871 b[n++] = TELOPT_NAWS;
872 b[n++] = telnet->term_width >> 8;
873 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
874 b[n++] = telnet->term_width & 0xFF;
875 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
876 b[n++] = telnet->term_height >> 8;
877 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
878 b[n++] = telnet->term_height & 0xFF;
879 if (b[n-1] == IAC) b[n++] = IAC; /* duplicate any IAC byte occurs */
882 telnet->bufsize = sk_write(telnet->s, (char *)b, n);
883 logbuf = dupprintf("client:\tSB NAWS %d,%d",
884 telnet->term_width, telnet->term_height);
885 logevent(telnet->frontend, logbuf);
890 * Send Telnet special codes.
892 static void telnet_special(void *handle, Telnet_Special code)
894 Telnet telnet = (Telnet) handle;
897 if (telnet->s == NULL)
904 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
908 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
912 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
916 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
920 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
924 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
928 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
932 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
936 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
940 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
944 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
948 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
951 /* In BINARY mode, CR-LF becomes just CR -
952 * and without the NUL suffix too. */
953 if (telnet->opt_states[o_we_bin.index] == ACTIVE)
954 telnet->bufsize = sk_write(telnet->s, "\r", 1);
956 telnet->bufsize = sk_write(telnet->s, "\r\n", 2);
960 telnet->bufsize = sk_write(telnet->s, (char *)b, 1);
961 telnet->bufsize = sk_write_oob(telnet->s, (char *)(b + 1), 1);
964 if (telnet->opt_states[o_echo.index] == INACTIVE ||
965 telnet->opt_states[o_echo.index] == REALLY_INACTIVE) {
966 telnet->opt_states[o_echo.index] = REQUESTED;
967 send_opt(telnet, o_echo.send, o_echo.option);
971 if (telnet->opt_states[o_echo.index] == ACTIVE) {
972 telnet->opt_states[o_echo.index] = REQUESTED;
973 send_opt(telnet, o_echo.nsend, o_echo.option);
977 if (telnet->opt_states[o_they_sga.index] == ACTIVE) {
979 telnet->bufsize = sk_write(telnet->s, (char *)b, 2);
983 break; /* never heard of it */
987 static const struct telnet_special *telnet_get_specials(void *handle)
989 static const struct telnet_special specials[] = {
990 {"Are You There", TS_AYT},
993 {"Erase Character", TS_EC},
994 {"Erase Line", TS_EL},
996 {"No Operation", TS_NOP},
998 {"Abort Process", TS_ABORT},
999 {"Abort Output", TS_AO},
1000 {"Interrupt Process", TS_IP},
1001 {"Suspend Process", TS_SUSP},
1003 {"End Of Record", TS_EOR},
1004 {"End Of File", TS_EOF},
1010 static int telnet_connected(void *handle)
1012 Telnet telnet = (Telnet) handle;
1013 return telnet->s != NULL;
1016 static int telnet_sendok(void *handle)
1018 /* Telnet telnet = (Telnet) handle; */
1022 static void telnet_unthrottle(void *handle, int backlog)
1024 Telnet telnet = (Telnet) handle;
1025 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
1028 static int telnet_ldisc(void *handle, int option)
1030 Telnet telnet = (Telnet) handle;
1031 if (option == LD_ECHO)
1032 return telnet->echoing;
1033 if (option == LD_EDIT)
1034 return telnet->editing;
1038 static void telnet_provide_ldisc(void *handle, void *ldisc)
1040 Telnet telnet = (Telnet) handle;
1041 telnet->ldisc = ldisc;
1044 static void telnet_provide_logctx(void *handle, void *logctx)
1046 /* This is a stub. */
1049 static int telnet_exitcode(void *handle)
1051 Telnet telnet = (Telnet) handle;
1052 if (telnet->s != NULL)
1053 return -1; /* still connected */
1055 /* Telnet doesn't transmit exit codes back to the client */
1060 * cfg_info for Telnet does nothing at all.
1062 static int telnet_cfg_info(void *handle)
1067 Backend telnet_backend = {
1075 telnet_get_specials,
1080 telnet_provide_ldisc,
1081 telnet_provide_logctx,