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) ( (x) != IAC && (x) != CR )
91 static char *telopt(int opt)
93 #define i(x) if (opt == TELOPT_ ## x) return #x;
138 static void telnet_size(void *handle, int width, int height);
141 int send; /* what we initially send */
142 int nsend; /* -ve send if requested to stop it */
143 int ack, nak; /* +ve and -ve acknowledgements */
144 int option; /* the option code */
145 int index; /* index into telnet->opt_states[] */
147 REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE
163 static const struct Opt o_naws =
164 { WILL, WONT, DO, DONT, TELOPT_NAWS, OPTINDEX_NAWS, REQUESTED };
165 static const struct Opt o_tspeed =
166 { WILL, WONT, DO, DONT, TELOPT_TSPEED, OPTINDEX_TSPEED, REQUESTED };
167 static const struct Opt o_ttype =
168 { WILL, WONT, DO, DONT, TELOPT_TTYPE, OPTINDEX_TTYPE, REQUESTED };
169 static const struct Opt o_oenv = { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON,
170 OPTINDEX_OENV, INACTIVE
172 static const struct Opt o_nenv = { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON,
173 OPTINDEX_NENV, REQUESTED
175 static const struct Opt o_echo =
176 { DO, DONT, WILL, WONT, TELOPT_ECHO, OPTINDEX_ECHO, REQUESTED };
177 static const struct Opt o_we_sga =
178 { WILL, WONT, DO, DONT, TELOPT_SGA, OPTINDEX_WE_SGA, REQUESTED };
179 static const struct Opt o_they_sga =
180 { DO, DONT, WILL, WONT, TELOPT_SGA, OPTINDEX_THEY_SGA, REQUESTED };
182 static const struct Opt *const opts[] = {
183 &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,
184 &o_we_sga, &o_they_sga, NULL
187 typedef struct telnet_tag {
188 const struct plug_function_table *fn;
189 /* the above field _must_ be first in the structure */
195 int term_width, term_height;
197 int opt_states[NUM_OPTS];
199 int echoing, editing;
208 TOP_LEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
209 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
214 #define TELNET_MAX_BACKLOG 4096
216 #define SB_DELTA 1024
218 static void c_write1(Telnet telnet, int c)
222 backlog = from_backend(telnet->frontend, 0, &cc, 1);
223 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
226 static void log_option(Telnet telnet, char *sender, int cmd, int option)
230 * The strange-looking "<?""?>" below is there to avoid a
231 * trigraph - a double question mark followed by > maps to a
232 * closing brace character!
234 buf = dupprintf("%s:\t%s %s", sender,
235 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
236 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<?""?>"),
238 logevent(telnet->frontend, buf);
242 static void send_opt(Telnet telnet, int cmd, int option)
249 telnet->bufsize = sk_write(telnet->s, b, 3);
250 log_option(telnet, "client", cmd, option);
253 static void deactivate_option(Telnet telnet, const struct Opt *o)
255 if (telnet->opt_states[o->index] == REQUESTED ||
256 telnet->opt_states[o->index] == ACTIVE)
257 send_opt(telnet, o->nsend, o->option);
258 telnet->opt_states[o->index] = REALLY_INACTIVE;
262 * Generate side effects of enabling or disabling an option.
264 static void option_side_effects(Telnet telnet, const struct Opt *o, int enabled)
266 if (o->option == TELOPT_ECHO && o->send == DO)
267 telnet->echoing = !enabled;
268 else if (o->option == TELOPT_SGA && o->send == DO)
269 telnet->editing = !enabled;
270 if (telnet->ldisc) /* cause ldisc to notice the change */
271 ldisc_send(telnet->ldisc, NULL, 0, 0);
273 /* Ensure we get the minimum options */
274 if (!telnet->activated) {
275 if (telnet->opt_states[o_echo.index] == INACTIVE) {
276 telnet->opt_states[o_echo.index] = REQUESTED;
277 send_opt(telnet, o_echo.send, o_echo.option);
279 if (telnet->opt_states[o_we_sga.index] == INACTIVE) {
280 telnet->opt_states[o_we_sga.index] = REQUESTED;
281 send_opt(telnet, o_we_sga.send, o_we_sga.option);
283 if (telnet->opt_states[o_they_sga.index] == INACTIVE) {
284 telnet->opt_states[o_they_sga.index] = REQUESTED;
285 send_opt(telnet, o_they_sga.send, o_they_sga.option);
287 telnet->activated = TRUE;
291 static void activate_option(Telnet telnet, const struct Opt *o)
293 if (o->send == WILL && o->option == TELOPT_NAWS)
294 telnet_size(telnet, telnet->term_width, telnet->term_height);
295 if (o->send == WILL &&
296 (o->option == TELOPT_NEW_ENVIRON ||
297 o->option == TELOPT_OLD_ENVIRON)) {
299 * We may only have one kind of ENVIRON going at a time.
300 * This is a hack, but who cares.
302 deactivate_option(telnet, o->option ==
303 TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
305 option_side_effects(telnet, o, 1);
308 static void refused_option(Telnet telnet, const struct Opt *o)
310 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
311 telnet->opt_states[o_oenv.index] == INACTIVE) {
312 send_opt(telnet, WILL, TELOPT_OLD_ENVIRON);
313 telnet->opt_states[o_oenv.index] = REQUESTED;
315 option_side_effects(telnet, o, 0);
318 static void proc_rec_opt(Telnet telnet, int cmd, int option)
320 const struct Opt *const *o;
322 log_option(telnet, "server", cmd, option);
323 for (o = opts; *o; o++) {
324 if ((*o)->option == option && (*o)->ack == cmd) {
325 switch (telnet->opt_states[(*o)->index]) {
327 telnet->opt_states[(*o)->index] = ACTIVE;
328 activate_option(telnet, *o);
333 telnet->opt_states[(*o)->index] = ACTIVE;
334 send_opt(telnet, (*o)->send, option);
335 activate_option(telnet, *o);
337 case REALLY_INACTIVE:
338 send_opt(telnet, (*o)->nsend, option);
342 } else if ((*o)->option == option && (*o)->nak == cmd) {
343 switch (telnet->opt_states[(*o)->index]) {
345 telnet->opt_states[(*o)->index] = INACTIVE;
346 refused_option(telnet, *o);
349 telnet->opt_states[(*o)->index] = INACTIVE;
350 send_opt(telnet, (*o)->nsend, option);
351 option_side_effects(telnet, *o, 0);
354 case REALLY_INACTIVE:
361 * If we reach here, the option was one we weren't prepared to
362 * cope with. So send a negative ack.
364 send_opt(telnet, (cmd == WILL ? DONT : WONT), option);
367 static void process_subneg(Telnet telnet)
369 unsigned char b[2048], *p, *q;
373 switch (telnet->sb_opt) {
375 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
379 b[2] = TELOPT_TSPEED;
381 strcpy(b + 4, cfg.termspeed);
382 n = 4 + strlen(cfg.termspeed);
385 telnet->bufsize = sk_write(telnet->s, b, n + 2);
386 logevent(telnet->frontend, "server:\tSB TSPEED SEND");
387 logbuf = dupprintf("client:\tSB TSPEED IS %s", cfg.termspeed);
388 logevent(telnet->frontend, logbuf);
391 logevent(telnet->frontend, "server:\tSB TSPEED <something weird>");
394 if (telnet->sb_len == 1 && telnet->sb_buf[0] == TELQUAL_SEND) {
400 for (n = 0; cfg.termtype[n]; n++)
401 b[n + 4] = (cfg.termtype[n] >= 'a'
402 && cfg.termtype[n] <=
403 'z' ? cfg.termtype[n] + 'A' -
404 'a' : cfg.termtype[n]);
407 telnet->bufsize = sk_write(telnet->s, b, n + 6);
409 logevent(telnet->frontend, "server:\tSB TTYPE SEND");
410 logbuf = dupprintf("client:\tSB TTYPE IS %s", b + 4);
411 logevent(telnet->frontend, logbuf);
414 logevent(telnet->frontend, "server:\tSB TTYPE <something weird>\r\n");
416 case TELOPT_OLD_ENVIRON:
417 case TELOPT_NEW_ENVIRON:
419 q = p + telnet->sb_len;
420 if (p < q && *p == TELQUAL_SEND) {
423 logbuf = dupprintf("server:\tSB %s SEND", telopt(telnet->sb_opt));
424 logevent(telnet->frontend, logbuf);
426 if (telnet->sb_opt == TELOPT_OLD_ENVIRON) {
427 if (cfg.rfc_environ) {
435 * Try to guess the sense of VAR and VALUE.
441 } else if (*p == BSD_VAR) {
449 * With NEW_ENVIRON, the sense of VAR and VALUE
457 b[2] = telnet->sb_opt;
463 while (*e && *e != '\t')
485 telnet->bufsize = sk_write(telnet->s, b, n);
486 logbuf = dupprintf("client:\tSB %s IS %s", telopt(telnet->sb_opt),
487 n == 6 ? "<nothing>" : "<stuff>");
488 logevent(telnet->frontend, logbuf);
495 static void do_telnet_read(Telnet telnet, char *buf, int len)
499 int c = (unsigned char) *buf++;
501 switch (telnet->state) {
504 if (c == NUL && telnet->state == SEENCR)
505 telnet->state = TOP_LEVEL;
507 telnet->state = SEENIAC;
509 if (!telnet->in_synch)
513 /* I can't get the F***ing winsock to insert the urgent IAC
514 * into the right position! Even with SO_OOBINLINE it gives
515 * it to recv too soon. And of course the DM byte (that
516 * arrives in the same packet!) appears several K later!!
518 * Oh well, we do get the DM in the right place so I'll
519 * just stop hiding on the next 0xf2 and hope for the best.
522 telnet->in_synch = 0;
525 telnet->state = SEENCR;
527 telnet->state = TOP_LEVEL;
532 telnet->state = SEENDO;
534 telnet->state = SEENDONT;
536 telnet->state = SEENWILL;
538 telnet->state = SEENWONT;
540 telnet->state = SEENSB;
542 telnet->in_synch = 0;
543 telnet->state = TOP_LEVEL;
545 /* ignore everything else; print it if it's IAC */
549 telnet->state = TOP_LEVEL;
553 proc_rec_opt(telnet, WILL, c);
554 telnet->state = TOP_LEVEL;
557 proc_rec_opt(telnet, WONT, c);
558 telnet->state = TOP_LEVEL;
561 proc_rec_opt(telnet, DO, c);
562 telnet->state = TOP_LEVEL;
565 proc_rec_opt(telnet, DONT, c);
566 telnet->state = TOP_LEVEL;
571 telnet->state = SUBNEGOT;
575 telnet->state = SUBNEG_IAC;
578 if (telnet->sb_len >= telnet->sb_size) {
580 telnet->sb_size += SB_DELTA;
581 newbuf = (telnet->sb_buf ?
582 srealloc(telnet->sb_buf, telnet->sb_size) :
583 smalloc(telnet->sb_size));
585 telnet->sb_buf = newbuf;
587 telnet->sb_size -= SB_DELTA;
589 if (telnet->sb_len < telnet->sb_size)
590 telnet->sb_buf[telnet->sb_len++] = c;
591 telnet->state = SUBNEGOT; /* in case we came here by goto */
596 goto subneg_addchar; /* yes, it's a hack, I know, but... */
598 process_subneg(telnet);
599 telnet->state = TOP_LEVEL;
606 static int telnet_closing(Plug plug, char *error_msg, int error_code,
609 Telnet telnet = (Telnet) plug;
616 /* A socket error has occurred. */
617 logevent(telnet->frontend, error_msg);
618 connection_fatal("%s", error_msg);
619 } /* Otherwise, the remote side closed the connection normally. */
623 static int telnet_receive(Plug plug, int urgent, char *data, int len)
625 Telnet telnet = (Telnet) plug;
627 telnet->in_synch = TRUE;
628 do_telnet_read(telnet, data, len);
632 static void telnet_sent(Plug plug, int bufsize)
634 Telnet telnet = (Telnet) plug;
635 telnet->bufsize = bufsize;
639 * Called to set up the Telnet connection.
641 * Returns an error message, or NULL on success.
643 * Also places the canonical host name into `realhost'. It must be
644 * freed by the caller.
646 static char *telnet_init(void *frontend_handle, void **backend_handle,
647 char *host, int port, char **realhost, int nodelay)
649 static const struct plug_function_table fn_table = {
658 telnet = smalloc(sizeof(*telnet));
659 telnet->fn = &fn_table;
661 telnet->echoing = TRUE;
662 telnet->editing = TRUE;
663 telnet->activated = FALSE;
664 telnet->sb_buf = NULL;
666 telnet->frontend = frontend_handle;
667 telnet->term_width = cfg.width;
668 telnet->term_height = cfg.height;
669 telnet->state = TOP_LEVEL;
670 *backend_handle = telnet;
677 buf = dupprintf("Looking up host \"%s\"", host);
678 logevent(telnet->frontend, buf);
681 addr = sk_namelookup(host, realhost);
682 if ((err = sk_addr_error(addr)))
686 port = 23; /* default telnet port */
692 char *buf, addrbuf[100];
693 sk_getaddr(addr, addrbuf, 100);
694 buf = dupprintf("Connecting to %s port %d", addrbuf, port);
695 logevent(telnet->frontend, buf);
698 telnet->s = new_connection(addr, *realhost, port, 0, 1,
699 nodelay, (Plug) telnet);
700 if ((err = sk_socket_error(telnet->s)))
706 * Initialise option states.
708 if (cfg.passive_telnet) {
709 const struct Opt *const *o;
711 for (o = opts; *o; o++)
712 telnet->opt_states[(*o)->index] = INACTIVE;
714 const struct Opt *const *o;
716 for (o = opts; *o; o++) {
717 telnet->opt_states[(*o)->index] = (*o)->initial_state;
718 if (telnet->opt_states[(*o)->index] == REQUESTED)
719 send_opt(telnet, (*o)->send, (*o)->option);
721 telnet->activated = TRUE;
725 * Set up SYNCH state.
727 telnet->in_synch = FALSE;
733 * Called to send data down the Telnet connection.
735 static int telnet_send(void *handle, char *buf, int len)
737 Telnet telnet = (Telnet) handle;
739 static unsigned char iac[2] = { IAC, IAC };
740 static unsigned char cr[2] = { CR, NUL };
742 static unsigned char nl[2] = { CR, LF };
745 if (telnet->s == NULL)
749 while (p < buf + len) {
752 while (p < buf + len && iswritable((unsigned char) *p))
754 telnet->bufsize = sk_write(telnet->s, q, p - q);
756 while (p < buf + len && !iswritable((unsigned char) *p)) {
758 sk_write(telnet->s, (unsigned char) *p == IAC ? iac : cr, 2);
763 return telnet->bufsize;
767 * Called to query the current socket sendability status.
769 static int telnet_sendbuffer(void *handle)
771 Telnet telnet = (Telnet) handle;
772 return telnet->bufsize;
776 * Called to set the size of the window from Telnet's POV.
778 static void telnet_size(void *handle, int width, int height)
780 Telnet telnet = (Telnet) handle;
784 telnet->term_width = width;
785 telnet->term_height = height;
787 if (telnet->s == NULL || telnet->opt_states[o_naws.index] != ACTIVE)
792 b[3] = telnet->term_width >> 8;
793 b[4] = telnet->term_width & 0xFF;
794 b[5] = telnet->term_height >> 8;
795 b[6] = telnet->term_height & 0xFF;
798 telnet->bufsize = sk_write(telnet->s, b, 9);
799 logbuf = dupprintf("client:\tSB NAWS %d,%d",
800 ((unsigned char) b[3] << 8) + (unsigned char) b[4],
801 ((unsigned char) b[5] << 8) + (unsigned char) b[6]);
802 logevent(telnet->frontend, logbuf);
807 * Send Telnet special codes.
809 static void telnet_special(void *handle, Telnet_Special code)
811 Telnet telnet = (Telnet) handle;
814 if (telnet->s == NULL)
821 telnet->bufsize = sk_write(telnet->s, b, 2);
825 telnet->bufsize = sk_write(telnet->s, b, 2);
829 telnet->bufsize = sk_write(telnet->s, b, 2);
833 telnet->bufsize = sk_write(telnet->s, b, 2);
837 telnet->bufsize = sk_write(telnet->s, b, 2);
841 telnet->bufsize = sk_write(telnet->s, b, 2);
845 telnet->bufsize = sk_write(telnet->s, b, 2);
849 telnet->bufsize = sk_write(telnet->s, b, 2);
853 telnet->bufsize = sk_write(telnet->s, b, 2);
857 telnet->bufsize = sk_write(telnet->s, b, 2);
861 telnet->bufsize = sk_write(telnet->s, b, 2);
865 telnet->bufsize = sk_write(telnet->s, b, 2);
868 telnet->bufsize = sk_write(telnet->s, "\r\n", 2);
872 telnet->bufsize = sk_write(telnet->s, b, 1);
873 telnet->bufsize = sk_write_oob(telnet->s, b + 1, 1);
876 if (telnet->opt_states[o_echo.index] == INACTIVE ||
877 telnet->opt_states[o_echo.index] == REALLY_INACTIVE) {
878 telnet->opt_states[o_echo.index] = REQUESTED;
879 send_opt(telnet, o_echo.send, o_echo.option);
883 if (telnet->opt_states[o_echo.index] == ACTIVE) {
884 telnet->opt_states[o_echo.index] = REQUESTED;
885 send_opt(telnet, o_echo.nsend, o_echo.option);
889 if (telnet->opt_states[o_they_sga.index] == ACTIVE) {
891 telnet->bufsize = sk_write(telnet->s, b, 2);
897 static Socket telnet_socket(void *handle)
899 Telnet telnet = (Telnet) handle;
903 static int telnet_sendok(void *handle)
905 /* Telnet telnet = (Telnet) handle; */
909 static void telnet_unthrottle(void *handle, int backlog)
911 Telnet telnet = (Telnet) handle;
912 sk_set_frozen(telnet->s, backlog > TELNET_MAX_BACKLOG);
915 static int telnet_ldisc(void *handle, int option)
917 Telnet telnet = (Telnet) handle;
918 if (option == LD_ECHO)
919 return telnet->echoing;
920 if (option == LD_EDIT)
921 return telnet->editing;
925 static void telnet_provide_ldisc(void *handle, void *ldisc)
927 Telnet telnet = (Telnet) handle;
928 telnet->ldisc = ldisc;
931 static void telnet_provide_logctx(void *handle, void *logctx)
933 /* This is a stub. */
936 static int telnet_exitcode(void *handle)
938 /* Telnet telnet = (Telnet) handle; */
939 /* Telnet doesn't transmit exit codes back to the client */
943 Backend telnet_backend = {
953 telnet_provide_ldisc,
954 telnet_provide_logctx,