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
) {
95 #define i(x) if (opt == TELOPT_ ## x) return #x;
96 i(BINARY
); i(ECHO
); i(RCP
); i(SGA
); i(NAMS
); i(STATUS
); i(TM
); i(RCTE
);
97 i(NAOL
); i(NAOP
); i(NAOCRD
); i(NAOHTS
); i(NAOHTD
); i(NAOFFD
); i(NAOVTS
);
98 i(NAOVTD
); i(NAOLFD
); i(XASCII
); i(LOGOUT
); i(BM
); i(DET
); i(SUPDUP
);
99 i(SUPDUPOUTPUT
); i(SNDLOC
); i(TTYPE
); i(EOR
); i(TUID
); i(OUTMRK
);
100 i(TTYLOC
); i(X3PAD
); i(NAWS
); i(TSPEED
); i(LFLOW
); i(LINEMODE
);
101 i(XDISPLOC
); i(OLD_ENVIRON
); i(AUTHENTICATION
); i(ENCRYPT
);
102 i(NEW_ENVIRON
); i(EXOPL
);
107 static void telnet_size(void);
110 int send
; /* what we initially send */
111 int nsend
; /* -ve send if requested to stop it */
112 int ack
, nak
; /* +ve and -ve acknowledgements */
113 int option
; /* the option code */
115 REQUESTED
, ACTIVE
, INACTIVE
, REALLY_INACTIVE
119 static struct Opt o_naws
= {WILL
, WONT
, DO
, DONT
, TELOPT_NAWS
, REQUESTED
};
120 static struct Opt o_tspeed
= {WILL
, WONT
, DO
, DONT
, TELOPT_TSPEED
, REQUESTED
};
121 static struct Opt o_ttype
= {WILL
, WONT
, DO
, DONT
, TELOPT_TTYPE
, REQUESTED
};
122 static struct Opt o_oenv
= {WILL
, WONT
, DO
, DONT
, TELOPT_OLD_ENVIRON
,
124 static struct Opt o_nenv
= {WILL
, WONT
, DO
, DONT
, TELOPT_NEW_ENVIRON
,
126 static struct Opt o_echo
= {DO
, DONT
, WILL
, WONT
, TELOPT_ECHO
, REQUESTED
};
127 static struct Opt o_we_sga
= {WILL
, WONT
, DO
, DONT
, TELOPT_SGA
, REQUESTED
};
128 static struct Opt o_they_sga
= {DO
, DONT
, WILL
, WONT
, TELOPT_SGA
, REQUESTED
};
130 static struct Opt
*opts
[] = {
131 &o_naws
, &o_tspeed
, &o_ttype
, &o_oenv
, &o_nenv
, &o_echo
,
132 &o_we_sga
, &o_they_sga
, NULL
135 static int echoing
= TRUE
, editing
= TRUE
;
138 static int sb_opt
, sb_len
;
139 static char *sb_buf
= NULL
;
140 static int sb_size
= 0;
141 #define SB_DELTA 1024
143 static void c_write1(int c
) {
145 from_backend(0, &cc
, 1);
148 static void log_option (char *sender
, int cmd
, int option
) {
150 sprintf(buf
, "%s:\t%s %s", sender
,
151 (cmd
== WILL ?
"WILL" : cmd
== WONT ?
"WONT" :
152 cmd
== DO ?
"DO" : cmd
== DONT ?
"DONT" : "<??>"),
157 static void send_opt (int cmd
, int option
) {
160 b
[0] = IAC
; b
[1] = cmd
; b
[2] = option
;
162 log_option("client", cmd
, option
);
165 static void deactivate_option (struct Opt
*o
) {
166 if (o
->state
== REQUESTED
|| o
->state
== ACTIVE
)
167 send_opt (o
->nsend
, o
->option
);
168 o
->state
= REALLY_INACTIVE
;
172 * Generate side effects of enabling or disabling an option.
174 static void option_side_effects(struct Opt
*o
, int enabled
) {
175 if (o
->option
== TELOPT_ECHO
&& o
->send
== DO
)
177 else if (o
->option
== TELOPT_SGA
&& o
->send
== DO
)
179 ldisc_send(NULL
, 0); /* cause ldisc to notice the change */
182 static void activate_option (struct Opt
*o
) {
183 if (o
->send
== WILL
&& o
->option
== TELOPT_NAWS
)
185 if (o
->send
== WILL
&&
186 (o
->option
== TELOPT_NEW_ENVIRON
||
187 o
->option
== TELOPT_OLD_ENVIRON
)) {
189 * We may only have one kind of ENVIRON going at a time.
190 * This is a hack, but who cares.
192 deactivate_option (o
->option
==TELOPT_NEW_ENVIRON ?
&o_oenv
: &o_nenv
);
194 option_side_effects(o
, 1);
197 static void refused_option (struct Opt
*o
) {
198 if (o
->send
== WILL
&& o
->option
== TELOPT_NEW_ENVIRON
&&
199 o_oenv
.state
== INACTIVE
) {
200 send_opt (WILL
, TELOPT_OLD_ENVIRON
);
201 o_oenv
.state
= REQUESTED
;
203 option_side_effects(o
, 0);
206 static void proc_rec_opt (int cmd
, int option
) {
209 log_option ("server", cmd
, option
);
210 for (o
= opts
; *o
; o
++) {
211 if ((*o
)->option
== option
&& (*o
)->ack
== cmd
) {
212 switch ((*o
)->state
) {
214 (*o
)->state
= ACTIVE
;
215 activate_option (*o
);
220 (*o
)->state
= ACTIVE
;
221 send_opt ((*o
)->send
, option
);
222 activate_option (*o
);
224 case REALLY_INACTIVE
:
225 send_opt ((*o
)->nsend
, option
);
229 } else if ((*o
)->option
== option
&& (*o
)->nak
== cmd
) {
230 switch ((*o
)->state
) {
232 (*o
)->state
= INACTIVE
;
236 (*o
)->state
= INACTIVE
;
237 send_opt ((*o
)->nsend
, option
);
238 option_side_effects(*o
, 0);
241 case REALLY_INACTIVE
:
248 * If we reach here, the option was one we weren't prepared to
249 * cope with. So send a negative ack.
251 send_opt ((cmd
== WILL ? DONT
: WONT
), option
);
254 static void process_subneg (void) {
255 unsigned char b
[2048], *p
, *q
;
261 if (sb_len
== 1 && sb_buf
[0] == TELQUAL_SEND
) {
262 char logbuf
[sizeof(cfg
.termspeed
)+80];
263 b
[0] = IAC
; b
[1] = SB
; b
[2] = TELOPT_TSPEED
;
265 strcpy(b
+4, cfg
.termspeed
);
266 n
= 4 + strlen(cfg
.termspeed
);
267 b
[n
] = IAC
; b
[n
+1] = SE
;
269 logevent("server:\tSB TSPEED SEND");
270 sprintf(logbuf
, "client:\tSB TSPEED IS %s", cfg
.termspeed
);
273 logevent ("server:\tSB TSPEED <something weird>");
276 if (sb_len
== 1 && sb_buf
[0] == TELQUAL_SEND
) {
277 char logbuf
[sizeof(cfg
.termtype
)+80];
278 b
[0] = IAC
; b
[1] = SB
; b
[2] = TELOPT_TTYPE
;
280 for (n
= 0; cfg
.termtype
[n
]; n
++)
281 b
[n
+4] = (cfg
.termtype
[n
] >= 'a' && cfg
.termtype
[n
] <= 'z' ?
282 cfg
.termtype
[n
] + 'A'-'a' : cfg
.termtype
[n
]);
283 b
[n
+4] = IAC
; b
[n
+5] = SE
;
286 logevent("server:\tSB TTYPE SEND");
287 sprintf(logbuf
, "client:\tSB TTYPE IS %s", b
+4);
290 logevent("server:\tSB TTYPE <something weird>\r\n");
292 case TELOPT_OLD_ENVIRON
:
293 case TELOPT_NEW_ENVIRON
:
296 if (p
< q
&& *p
== TELQUAL_SEND
) {
299 sprintf (logbuf
, "server:\tSB %s SEND", telopt(sb_opt
));
301 if (sb_opt
== TELOPT_OLD_ENVIRON
) {
302 if (cfg
.rfc_environ
) {
310 * Try to guess the sense of VAR and VALUE.
316 } else if (*p
== BSD_VAR
) {
324 * With NEW_ENVIRON, the sense of VAR and VALUE
330 b
[0] = IAC
; b
[1] = SB
; b
[2] = sb_opt
;
336 while (*e
&& *e
!= '\t') b
[n
++] = *e
++;
339 while (*e
) b
[n
++] = *e
++;
343 b
[n
++] = var
; b
[n
++] = 'U'; b
[n
++] = 'S';
344 b
[n
++] = 'E'; b
[n
++] = 'R'; b
[n
++] = value
;
346 while (*e
) b
[n
++] = *e
++;
348 b
[n
++] = IAC
; b
[n
++] = SE
;
350 sprintf(logbuf
, "client:\tSB %s IS %s", telopt(sb_opt
),
351 n
==6 ?
"<nothing>" : "<stuff>");
359 TOPLEVEL
, SEENIAC
, SEENWILL
, SEENWONT
, SEENDO
, SEENDONT
,
360 SEENSB
, SUBNEGOT
, SUBNEG_IAC
, SEENCR
361 } telnet_state
= TOPLEVEL
;
363 static void do_telnet_read (char *buf
, int len
) {
366 int c
= (unsigned char) *buf
++;
368 switch (telnet_state
) {
371 if (c
== NUL
&& telnet_state
== SEENCR
)
372 telnet_state
= TOPLEVEL
;
374 telnet_state
= SEENIAC
;
380 /* I can't get the F***ing winsock to insert the urgent IAC
381 * into the right position! Even with SO_OOBINLINE it gives
382 * it to recv too soon. And of course the DM byte (that
383 * arrives in the same packet!) appears several K later!!
385 * Oh well, we do get the DM in the right place so I'll
386 * just stop hiding on the next 0xf2 and hope for the best.
388 else if (c
== DM
) in_synch
= 0;
391 telnet_state
= SEENCR
;
393 telnet_state
= TOPLEVEL
;
397 if (c
== DO
) telnet_state
= SEENDO
;
398 else if (c
== DONT
) telnet_state
= SEENDONT
;
399 else if (c
== WILL
) telnet_state
= SEENWILL
;
400 else if (c
== WONT
) telnet_state
= SEENWONT
;
401 else if (c
== SB
) telnet_state
= SEENSB
;
404 telnet_state
= TOPLEVEL
;
407 /* ignore everything else; print it if it's IAC */
411 telnet_state
= TOPLEVEL
;
415 proc_rec_opt (WILL
, c
);
416 telnet_state
= TOPLEVEL
;
419 proc_rec_opt (WONT
, c
);
420 telnet_state
= TOPLEVEL
;
423 proc_rec_opt (DO
, c
);
424 telnet_state
= TOPLEVEL
;
427 proc_rec_opt (DONT
, c
);
428 telnet_state
= TOPLEVEL
;
433 telnet_state
= SUBNEGOT
;
437 telnet_state
= SUBNEG_IAC
;
440 if (sb_len
>= sb_size
) {
444 srealloc(sb_buf
, sb_size
) :
451 if (sb_len
< sb_size
)
452 sb_buf
[sb_len
++] = c
;
453 telnet_state
= SUBNEGOT
;/* in case we came here by goto */
458 goto subneg_addchar
; /* yes, it's a hack, I know, but... */
461 telnet_state
= TOPLEVEL
;
468 static int telnet_closing (Plug plug
, char *error_msg
, int error_code
, int calling_back
) {
472 /* A socket error has occurred. */
473 connection_fatal (error_msg
);
474 } /* Otherwise, the remote side closed the connection normally. */
478 static int telnet_receive(Plug plug
, int urgent
, char *data
, int len
) {
479 if(urgent
) in_synch
= TRUE
;
480 do_telnet_read (data
, len
);
485 * Called to set up the Telnet connection.
487 * Returns an error message, or NULL on success.
489 * Also places the canonical host name into `realhost'.
491 static char *telnet_init (char *host
, int port
, char **realhost
) {
492 static struct plug_function_table fn_table
= {
495 }, *fn_table_ptr
= &fn_table
;
503 addr
= sk_namelookup(host
, realhost
);
504 if ( (err
= sk_addr_error(addr
)) )
508 port
= 23; /* default telnet port */
513 s
= sk_new(addr
, port
, 0, 1, &fn_table_ptr
);
514 if ( (err
= sk_socket_error(s
)) )
520 * Initialise option states.
525 for (o
= opts
; *o
; o
++)
526 if ((*o
)->state
== REQUESTED
)
527 send_opt ((*o
)->send
, (*o
)->option
);
531 * Set up SYNCH state.
539 * Called to send data down the Telnet connection.
541 static void telnet_send (char *buf
, int len
) {
543 static unsigned char iac
[2] = { IAC
, IAC
};
544 static unsigned char cr
[2] = { CR
, NUL
};
545 static unsigned char nl
[2] = { CR
, LF
};
551 while (p
< buf
+len
) {
554 while (iswritable((unsigned char)*p
) && p
< buf
+len
) p
++;
557 while (p
< buf
+len
&& !iswritable((unsigned char)*p
)) {
558 sk_write(s
, (unsigned char)*p
== IAC ? iac
: nl
, 2);
565 * Called to set the size of the window from Telnet's POV.
567 static void telnet_size(void) {
571 if (s
== NULL
|| o_naws
.state
!= ACTIVE
)
573 b
[0] = IAC
; b
[1] = SB
; b
[2] = TELOPT_NAWS
;
574 b
[3] = cols
>> 8; b
[4] = cols
& 0xFF;
575 b
[5] = rows
>> 8; b
[6] = rows
& 0xFF;
576 b
[7] = IAC
; b
[8] = SE
;
578 sprintf(logbuf
, "client:\tSB NAWS %d,%d",
579 ((unsigned char)b
[3] << 8) + (unsigned char)b
[4],
580 ((unsigned char)b
[5] << 8) + (unsigned char)b
[6]);
585 * Send Telnet special codes.
587 static void telnet_special (Telnet_Special code
) {
595 case TS_AYT
: b
[1] = AYT
; sk_write(s
, b
, 2); break;
596 case TS_BRK
: b
[1] = BREAK
; sk_write(s
, b
, 2); break;
597 case TS_EC
: b
[1] = EC
; sk_write(s
, b
, 2); break;
598 case TS_EL
: b
[1] = EL
; sk_write(s
, b
, 2); break;
599 case TS_GA
: b
[1] = GA
; sk_write(s
, b
, 2); break;
600 case TS_NOP
: b
[1] = NOP
; sk_write(s
, b
, 2); break;
601 case TS_ABORT
: b
[1] = ABORT
; sk_write(s
, b
, 2); break;
602 case TS_AO
: b
[1] = AO
; sk_write(s
, b
, 2); break;
603 case TS_IP
: b
[1] = IP
; sk_write(s
, b
, 2); break;
604 case TS_SUSP
: b
[1] = SUSP
; sk_write(s
, b
, 2); break;
605 case TS_EOR
: b
[1] = EOR
; sk_write(s
, b
, 2); break;
606 case TS_EOF
: b
[1] = xEOF
; sk_write(s
, b
, 2); break;
610 sk_write_oob (s
, b
+1, 1);
613 if (o_echo
.state
== INACTIVE
|| o_echo
.state
== REALLY_INACTIVE
) {
614 o_echo
.state
= REQUESTED
;
615 send_opt (o_echo
.send
, o_echo
.option
);
619 if (o_echo
.state
== ACTIVE
) {
620 o_echo
.state
= REQUESTED
;
621 send_opt (o_echo
.nsend
, o_echo
.option
);
625 if (o_they_sga
.state
== ACTIVE
) {
633 static Socket
telnet_socket(void) { return s
; }
635 static int telnet_sendok(void) { return 1; }
637 static int telnet_ldisc(int option
) {
638 if (option
== LD_ECHO
) return echoing
;
639 if (option
== LD_EDIT
) return editing
;
643 Backend telnet_backend
= {