14 static Socket s = NULL;
16 #define IAC 255 /* interpret as command: */
17 #define DONT 254 /* you are not to use option */
18 #define DO 253 /* please, you use option */
19 #define WONT 252 /* I won't use option */
20 #define WILL 251 /* I will use option */
21 #define SB 250 /* interpret as subnegotiation */
22 #define SE 240 /* end sub negotiation */
24 #define GA 249 /* you may reverse the line */
25 #define EL 248 /* erase the current line */
26 #define EC 247 /* erase the current character */
27 #define AYT 246 /* are you there */
28 #define AO 245 /* abort output--but let prog finish */
29 #define IP 244 /* interrupt process--permanently */
30 #define BREAK 243 /* break */
31 #define DM 242 /* data mark--for connect. cleaning */
32 #define NOP 241 /* nop */
33 #define EOR 239 /* end of record (transparent mode) */
34 #define ABORT 238 /* Abort process */
35 #define SUSP 237 /* Suspend process */
36 #define xEOF 236 /* End of file: EOF is already used... */
38 #define TELOPT_BINARY 0 /* 8-bit data path */
39 #define TELOPT_ECHO 1 /* echo */
40 #define TELOPT_RCP 2 /* prepare to reconnect */
41 #define TELOPT_SGA 3 /* suppress go ahead */
42 #define TELOPT_NAMS 4 /* approximate message size */
43 #define TELOPT_STATUS 5 /* give status */
44 #define TELOPT_TM 6 /* timing mark */
45 #define TELOPT_RCTE 7 /* remote controlled transmission and echo */
46 #define TELOPT_NAOL 8 /* negotiate about output line width */
47 #define TELOPT_NAOP 9 /* negotiate about output page size */
48 #define TELOPT_NAOCRD 10 /* negotiate about CR disposition */
49 #define TELOPT_NAOHTS 11 /* negotiate about horizontal tabstops */
50 #define TELOPT_NAOHTD 12 /* negotiate about horizontal tab disposition */
51 #define TELOPT_NAOFFD 13 /* negotiate about formfeed disposition */
52 #define TELOPT_NAOVTS 14 /* negotiate about vertical tab stops */
53 #define TELOPT_NAOVTD 15 /* negotiate about vertical tab disposition */
54 #define TELOPT_NAOLFD 16 /* negotiate about output LF disposition */
55 #define TELOPT_XASCII 17 /* extended ascic character set */
56 #define TELOPT_LOGOUT 18 /* force logout */
57 #define TELOPT_BM 19 /* byte macro */
58 #define TELOPT_DET 20 /* data entry terminal */
59 #define TELOPT_SUPDUP 21 /* supdup protocol */
60 #define TELOPT_SUPDUPOUTPUT 22 /* supdup output */
61 #define TELOPT_SNDLOC 23 /* send location */
62 #define TELOPT_TTYPE 24 /* terminal type */
63 #define TELOPT_EOR 25 /* end or record */
64 #define TELOPT_TUID 26 /* TACACS user identification */
65 #define TELOPT_OUTMRK 27 /* output marking */
66 #define TELOPT_TTYLOC 28 /* terminal location number */
67 #define TELOPT_3270REGIME 29 /* 3270 regime */
68 #define TELOPT_X3PAD 30 /* X.3 PAD */
69 #define TELOPT_NAWS 31 /* window size */
70 #define TELOPT_TSPEED 32 /* terminal speed */
71 #define TELOPT_LFLOW 33 /* remote flow control */
72 #define TELOPT_LINEMODE 34 /* Linemode option */
73 #define TELOPT_XDISPLOC 35 /* X Display Location */
74 #define TELOPT_OLD_ENVIRON 36 /* Old - Environment variables */
75 #define TELOPT_AUTHENTICATION 37 /* Authenticate */
76 #define TELOPT_ENCRYPT 38 /* Encryption option */
77 #define TELOPT_NEW_ENVIRON 39 /* New - Environment variables */
78 #define TELOPT_EXOPL 255 /* extended-options-list */
80 #define TELQUAL_IS 0 /* option is... */
81 #define TELQUAL_SEND 1 /* send option */
82 #define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
92 #define iswritable(x) ( (x) != IAC && (x) != CR )
94 static char *telopt(int opt)
96 #define i(x) if (opt == TELOPT_ ## x) return #x;
141 static void telnet_size(void);
144 int send; /* what we initially send */
145 int nsend; /* -ve send if requested to stop it */
146 int ack, nak; /* +ve and -ve acknowledgements */
147 int option; /* the option code */
149 REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE
153 static struct Opt o_naws =
154 { WILL, WONT, DO, DONT, TELOPT_NAWS, REQUESTED };
155 static struct Opt o_tspeed =
156 { WILL, WONT, DO, DONT, TELOPT_TSPEED, REQUESTED };
157 static struct Opt o_ttype =
158 { WILL, WONT, DO, DONT, TELOPT_TTYPE, REQUESTED };
159 static struct Opt o_oenv = { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON,
162 static struct Opt o_nenv = { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON,
165 static struct Opt o_echo =
166 { DO, DONT, WILL, WONT, TELOPT_ECHO, REQUESTED };
167 static struct Opt o_we_sga =
168 { WILL, WONT, DO, DONT, TELOPT_SGA, REQUESTED };
169 static struct Opt o_they_sga =
170 { DO, DONT, WILL, WONT, TELOPT_SGA, REQUESTED };
172 static struct Opt *opts[] = {
173 &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,
174 &o_we_sga, &o_they_sga, NULL
177 static int echoing = TRUE, editing = TRUE;
180 static int sb_opt, sb_len;
181 static char *sb_buf = NULL;
182 static int sb_size = 0;
183 #define SB_DELTA 1024
185 static void c_write1(int c)
188 from_backend(0, &cc, 1);
191 static void log_option(char *sender, int cmd, int option)
194 sprintf(buf, "%s:\t%s %s", sender,
195 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
196 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<??>"),
201 static void send_opt(int cmd, int option)
209 log_option("client", cmd, option);
212 static void deactivate_option(struct Opt *o)
214 if (o->state == REQUESTED || o->state == ACTIVE)
215 send_opt(o->nsend, o->option);
216 o->state = REALLY_INACTIVE;
220 * Generate side effects of enabling or disabling an option.
222 static void option_side_effects(struct Opt *o, int enabled)
224 if (o->option == TELOPT_ECHO && o->send == DO)
226 else if (o->option == TELOPT_SGA && o->send == DO)
228 ldisc_send(NULL, 0); /* cause ldisc to notice the change */
231 static void activate_option(struct Opt *o)
233 if (o->send == WILL && o->option == TELOPT_NAWS)
235 if (o->send == WILL &&
236 (o->option == TELOPT_NEW_ENVIRON ||
237 o->option == TELOPT_OLD_ENVIRON)) {
239 * We may only have one kind of ENVIRON going at a time.
240 * This is a hack, but who cares.
242 deactivate_option(o->option ==
243 TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
245 option_side_effects(o, 1);
248 static void refused_option(struct Opt *o)
250 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
251 o_oenv.state == INACTIVE) {
252 send_opt(WILL, TELOPT_OLD_ENVIRON);
253 o_oenv.state = REQUESTED;
255 option_side_effects(o, 0);
258 static void proc_rec_opt(int cmd, int option)
262 log_option("server", cmd, option);
263 for (o = opts; *o; o++) {
264 if ((*o)->option == option && (*o)->ack == cmd) {
265 switch ((*o)->state) {
267 (*o)->state = ACTIVE;
273 (*o)->state = ACTIVE;
274 send_opt((*o)->send, option);
277 case REALLY_INACTIVE:
278 send_opt((*o)->nsend, option);
282 } else if ((*o)->option == option && (*o)->nak == cmd) {
283 switch ((*o)->state) {
285 (*o)->state = INACTIVE;
289 (*o)->state = INACTIVE;
290 send_opt((*o)->nsend, option);
291 option_side_effects(*o, 0);
294 case REALLY_INACTIVE:
301 * If we reach here, the option was one we weren't prepared to
302 * cope with. So send a negative ack.
304 send_opt((cmd == WILL ? DONT : WONT), option);
307 static void process_subneg(void)
309 unsigned char b[2048], *p, *q;
315 if (sb_len == 1 && sb_buf[0] == TELQUAL_SEND) {
316 char logbuf[sizeof(cfg.termspeed) + 80];
319 b[2] = TELOPT_TSPEED;
321 strcpy(b + 4, cfg.termspeed);
322 n = 4 + strlen(cfg.termspeed);
325 sk_write(s, b, n + 2);
326 logevent("server:\tSB TSPEED SEND");
327 sprintf(logbuf, "client:\tSB TSPEED IS %s", cfg.termspeed);
330 logevent("server:\tSB TSPEED <something weird>");
333 if (sb_len == 1 && sb_buf[0] == TELQUAL_SEND) {
334 char logbuf[sizeof(cfg.termtype) + 80];
339 for (n = 0; cfg.termtype[n]; n++)
340 b[n + 4] = (cfg.termtype[n] >= 'a'
341 && cfg.termtype[n] <=
342 'z' ? cfg.termtype[n] + 'A' -
343 'a' : cfg.termtype[n]);
346 sk_write(s, b, n + 6);
348 logevent("server:\tSB TTYPE SEND");
349 sprintf(logbuf, "client:\tSB TTYPE IS %s", b + 4);
352 logevent("server:\tSB TTYPE <something weird>\r\n");
354 case TELOPT_OLD_ENVIRON:
355 case TELOPT_NEW_ENVIRON:
358 if (p < q && *p == TELQUAL_SEND) {
361 sprintf(logbuf, "server:\tSB %s SEND", telopt(sb_opt));
363 if (sb_opt == TELOPT_OLD_ENVIRON) {
364 if (cfg.rfc_environ) {
372 * Try to guess the sense of VAR and VALUE.
378 } else if (*p == BSD_VAR) {
386 * With NEW_ENVIRON, the sense of VAR and VALUE
400 while (*e && *e != '\t')
423 sprintf(logbuf, "client:\tSB %s IS %s", telopt(sb_opt),
424 n == 6 ? "<nothing>" : "<stuff>");
432 TOPLEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
433 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
434 } telnet_state = TOPLEVEL;
436 static void do_telnet_read(char *buf, int len)
440 int c = (unsigned char) *buf++;
442 switch (telnet_state) {
445 if (c == NUL && telnet_state == SEENCR)
446 telnet_state = TOPLEVEL;
448 telnet_state = SEENIAC;
454 /* I can't get the F***ing winsock to insert the urgent IAC
455 * into the right position! Even with SO_OOBINLINE it gives
456 * it to recv too soon. And of course the DM byte (that
457 * arrives in the same packet!) appears several K later!!
459 * Oh well, we do get the DM in the right place so I'll
460 * just stop hiding on the next 0xf2 and hope for the best.
466 telnet_state = SEENCR;
468 telnet_state = TOPLEVEL;
473 telnet_state = SEENDO;
475 telnet_state = SEENDONT;
477 telnet_state = SEENWILL;
479 telnet_state = SEENWONT;
481 telnet_state = SEENSB;
484 telnet_state = TOPLEVEL;
486 /* ignore everything else; print it if it's IAC */
490 telnet_state = TOPLEVEL;
494 proc_rec_opt(WILL, c);
495 telnet_state = TOPLEVEL;
498 proc_rec_opt(WONT, c);
499 telnet_state = TOPLEVEL;
503 telnet_state = TOPLEVEL;
506 proc_rec_opt(DONT, c);
507 telnet_state = TOPLEVEL;
512 telnet_state = SUBNEGOT;
516 telnet_state = SUBNEG_IAC;
519 if (sb_len >= sb_size) {
523 srealloc(sb_buf, sb_size) :
530 if (sb_len < sb_size)
531 sb_buf[sb_len++] = c;
532 telnet_state = SUBNEGOT; /* in case we came here by goto */
537 goto subneg_addchar; /* yes, it's a hack, I know, but... */
540 telnet_state = TOPLEVEL;
547 static int telnet_closing(Plug plug, char *error_msg, int error_code,
553 /* A socket error has occurred. */
554 connection_fatal(error_msg);
555 } /* Otherwise, the remote side closed the connection normally. */
559 static int telnet_receive(Plug plug, int urgent, char *data, int len)
563 do_telnet_read(data, len);
568 * Called to set up the Telnet connection.
570 * Returns an error message, or NULL on success.
572 * Also places the canonical host name into `realhost'.
574 static char *telnet_init(char *host, int port, char **realhost)
576 static struct plug_function_table fn_table = {
579 }, *fn_table_ptr = &fn_table;
587 addr = sk_namelookup(host, realhost);
588 if ((err = sk_addr_error(addr)))
592 port = 23; /* default telnet port */
597 s = sk_new(addr, port, 0, 1, &fn_table_ptr);
598 if ((err = sk_socket_error(s)))
604 * Initialise option states.
609 for (o = opts; *o; o++)
610 if ((*o)->state == REQUESTED)
611 send_opt((*o)->send, (*o)->option);
615 * Set up SYNCH state.
623 * Called to send data down the Telnet connection.
625 static void telnet_send(char *buf, int len)
628 static unsigned char iac[2] = { IAC, IAC };
629 static unsigned char cr[2] = { CR, NUL };
630 static unsigned char nl[2] = { CR, LF };
636 while (p < buf + len) {
639 while (iswritable((unsigned char) *p) && p < buf + len)
641 sk_write(s, q, p - q);
643 while (p < buf + len && !iswritable((unsigned char) *p)) {
644 sk_write(s, (unsigned char) *p == IAC ? iac : nl, 2);
651 * Called to set the size of the window from Telnet's POV.
653 static void telnet_size(void)
658 if (s == NULL || o_naws.state != ACTIVE)
670 sprintf(logbuf, "client:\tSB NAWS %d,%d",
671 ((unsigned char) b[3] << 8) + (unsigned char) b[4],
672 ((unsigned char) b[5] << 8) + (unsigned char) b[6]);
677 * Send Telnet special codes.
679 static void telnet_special(Telnet_Special code)
739 sk_write_oob(s, b + 1, 1);
742 if (o_echo.state == INACTIVE || o_echo.state == REALLY_INACTIVE) {
743 o_echo.state = REQUESTED;
744 send_opt(o_echo.send, o_echo.option);
748 if (o_echo.state == ACTIVE) {
749 o_echo.state = REQUESTED;
750 send_opt(o_echo.nsend, o_echo.option);
754 if (o_they_sga.state == ACTIVE) {
762 static Socket telnet_socket(void)
767 static int telnet_sendok(void)
772 static int telnet_ldisc(int option)
774 if (option == LD_ECHO)
776 if (option == LD_EDIT)
781 Backend telnet_backend = {