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Robert de Bath's patch: integrate line disciplines into Telnet and have them
[u/mdw/putty] / telnet.c
1 #include <windows.h>
2 #include <stdio.h>
3 #include <stdlib.h>
4 #include <winsock.h>
5
6 #include "putty.h"
7
8 #ifndef FALSE
9 #define FALSE 0
10 #endif
11 #ifndef TRUE
12 #define TRUE 1
13 #endif
14
15 static SOCKET s = INVALID_SOCKET;
16
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 */
24
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... */
38
39 #define TELOPT_BINARY 0 /* 8-bit data path */
40 #define TELOPT_ECHO 1 /* echo */
41 #define TELOPT_RCP 2 /* prepare to reconnect */
42 #define TELOPT_SGA 3 /* suppress go ahead */
43 #define TELOPT_NAMS 4 /* approximate message size */
44 #define TELOPT_STATUS 5 /* give status */
45 #define TELOPT_TM 6 /* timing mark */
46 #define TELOPT_RCTE 7 /* remote controlled transmission and echo */
47 #define TELOPT_NAOL 8 /* negotiate about output line width */
48 #define TELOPT_NAOP 9 /* negotiate about output page size */
49 #define TELOPT_NAOCRD 10 /* negotiate about CR disposition */
50 #define TELOPT_NAOHTS 11 /* negotiate about horizontal tabstops */
51 #define TELOPT_NAOHTD 12 /* negotiate about horizontal tab disposition */
52 #define TELOPT_NAOFFD 13 /* negotiate about formfeed disposition */
53 #define TELOPT_NAOVTS 14 /* negotiate about vertical tab stops */
54 #define TELOPT_NAOVTD 15 /* negotiate about vertical tab disposition */
55 #define TELOPT_NAOLFD 16 /* negotiate about output LF disposition */
56 #define TELOPT_XASCII 17 /* extended ascic character set */
57 #define TELOPT_LOGOUT 18 /* force logout */
58 #define TELOPT_BM 19 /* byte macro */
59 #define TELOPT_DET 20 /* data entry terminal */
60 #define TELOPT_SUPDUP 21 /* supdup protocol */
61 #define TELOPT_SUPDUPOUTPUT 22 /* supdup output */
62 #define TELOPT_SNDLOC 23 /* send location */
63 #define TELOPT_TTYPE 24 /* terminal type */
64 #define TELOPT_EOR 25 /* end or record */
65 #define TELOPT_TUID 26 /* TACACS user identification */
66 #define TELOPT_OUTMRK 27 /* output marking */
67 #define TELOPT_TTYLOC 28 /* terminal location number */
68 #define TELOPT_3270REGIME 29 /* 3270 regime */
69 #define TELOPT_X3PAD 30 /* X.3 PAD */
70 #define TELOPT_NAWS 31 /* window size */
71 #define TELOPT_TSPEED 32 /* terminal speed */
72 #define TELOPT_LFLOW 33 /* remote flow control */
73 #define TELOPT_LINEMODE 34 /* Linemode option */
74 #define TELOPT_XDISPLOC 35 /* X Display Location */
75 #define TELOPT_OLD_ENVIRON 36 /* Old - Environment variables */
76 #define TELOPT_AUTHENTICATION 37/* Authenticate */
77 #define TELOPT_ENCRYPT 38 /* Encryption option */
78 #define TELOPT_NEW_ENVIRON 39 /* New - Environment variables */
79 #define TELOPT_EXOPL 255 /* extended-options-list */
80
81 #define TELQUAL_IS 0 /* option is... */
82 #define TELQUAL_SEND 1 /* send option */
83 #define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
84 #define BSD_VAR 1
85 #define BSD_VALUE 0
86 #define RFC_VAR 0
87 #define RFC_VALUE 1
88
89 #define CR 13
90 #define LF 10
91 #define NUL 0
92
93 #define iswritable(x) ( (x) != IAC && (x) != CR )
94
95 static char *telopt(int opt) {
96 #define i(x) if (opt == TELOPT_ ## x) return #x;
97 i(BINARY); i(ECHO); i(RCP); i(SGA); i(NAMS); i(STATUS); i(TM); i(RCTE);
98 i(NAOL); i(NAOP); i(NAOCRD); i(NAOHTS); i(NAOHTD); i(NAOFFD); i(NAOVTS);
99 i(NAOVTD); i(NAOLFD); i(XASCII); i(LOGOUT); i(BM); i(DET); i(SUPDUP);
100 i(SUPDUPOUTPUT); i(SNDLOC); i(TTYPE); i(EOR); i(TUID); i(OUTMRK);
101 i(TTYLOC); i(X3PAD); i(NAWS); i(TSPEED); i(LFLOW); i(LINEMODE);
102 i(XDISPLOC); i(OLD_ENVIRON); i(AUTHENTICATION); i(ENCRYPT);
103 i(NEW_ENVIRON); i(EXOPL);
104 #undef i
105 return "<unknown>";
106 }
107
108 static void telnet_size(void);
109
110 struct Opt {
111 int send; /* what we initially send */
112 int nsend; /* -ve send if requested to stop it */
113 int ack, nak; /* +ve and -ve acknowledgements */
114 int option; /* the option code */
115 enum {
116 REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE
117 } state;
118 };
119
120 static struct Opt o_naws = {WILL, WONT, DO, DONT, TELOPT_NAWS, REQUESTED};
121 static struct Opt o_tspeed = {WILL, WONT, DO, DONT, TELOPT_TSPEED, REQUESTED};
122 static struct Opt o_ttype = {WILL, WONT, DO, DONT, TELOPT_TTYPE, REQUESTED};
123 static struct Opt o_oenv = {WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON,
124 INACTIVE};
125 static struct Opt o_nenv = {WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON,
126 REQUESTED};
127 static struct Opt o_echo = {DO, DONT, WILL, WONT, TELOPT_ECHO, REQUESTED};
128 static struct Opt o_we_sga = {WILL, WONT, DO, DONT, TELOPT_SGA, REQUESTED};
129 static struct Opt o_they_sga = {DO, DONT, WILL, WONT, TELOPT_SGA, REQUESTED};
130
131 static struct Opt *opts[] = {
132 &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,
133 &o_we_sga, &o_they_sga, NULL
134 };
135
136 #if 0
137 static int in_synch;
138 #endif
139
140 static int sb_opt, sb_len;
141 static char *sb_buf = NULL;
142 static int sb_size = 0;
143 #define SB_DELTA 1024
144
145 static void try_write (void) {
146 while (outbuf_head != outbuf_reap) {
147 int end = (outbuf_reap < outbuf_head ? outbuf_head : OUTBUF_SIZE);
148 int len = end - outbuf_reap;
149 int ret;
150
151 ret = send (s, outbuf+outbuf_reap, len, 0);
152 if (ret > 0)
153 outbuf_reap = (outbuf_reap + ret) & OUTBUF_MASK;
154 if (ret < len)
155 return;
156 }
157 }
158
159 static void s_write (void *buf, int len) {
160 unsigned char *p = buf;
161 while (len--) {
162 int new_head = (outbuf_head + 1) & OUTBUF_MASK;
163 if (new_head != outbuf_reap) {
164 outbuf[outbuf_head] = *p++;
165 outbuf_head = new_head;
166 }
167 }
168 try_write();
169 }
170
171 static void c_write (char *buf, int len) {
172 while (len--) {
173 int new_head = (inbuf_head + 1) & INBUF_MASK;
174 if (new_head != inbuf_reap) {
175 inbuf[inbuf_head] = *buf++;
176 inbuf_head = new_head;
177 } else {
178 term_out();
179 if( inbuf_head == inbuf_reap ) len++; else break;
180 }
181 }
182 }
183
184 static void log_option (char *sender, int cmd, int option) {
185 char buf[50];
186 sprintf(buf, "%s:\t%s %s", sender,
187 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
188 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<??>"),
189 telopt(option));
190 logevent(buf);
191 }
192
193 static void send_opt (int cmd, int option) {
194 unsigned char b[3];
195
196 b[0] = IAC; b[1] = cmd; b[2] = option;
197 s_write (b, 3);
198 log_option("client", cmd, option);
199 }
200
201 static void deactivate_option (struct Opt *o) {
202 if (o->state == REQUESTED || o->state == ACTIVE)
203 send_opt (o->nsend, o->option);
204 o->state = REALLY_INACTIVE;
205 }
206
207 static void activate_option (struct Opt *o) {
208 if (o->send == WILL && o->option == TELOPT_NAWS)
209 telnet_size();
210 if (o->send == WILL &&
211 (o->option == TELOPT_NEW_ENVIRON ||
212 o->option == TELOPT_OLD_ENVIRON)) {
213 /*
214 * We may only have one kind of ENVIRON going at a time.
215 * This is a hack, but who cares.
216 */
217 deactivate_option (o->option==TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
218 }
219 if (o->option == TELOPT_ECHO)
220 {
221 cfg.ldisc_term = FALSE;
222 ldisc = &ldisc_simple;
223 }
224 }
225
226 static void refused_option (struct Opt *o) {
227 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
228 o_oenv.state == INACTIVE) {
229 send_opt (WILL, TELOPT_OLD_ENVIRON);
230 o_oenv.state = REQUESTED;
231 }
232 if (o->option == TELOPT_ECHO)
233 {
234 cfg.ldisc_term = TRUE;
235 ldisc = &ldisc_term;
236 }
237 }
238
239 static void proc_rec_opt (int cmd, int option) {
240 struct Opt **o;
241
242 log_option ("server", cmd, option);
243 for (o = opts; *o; o++) {
244 if ((*o)->option == option && (*o)->ack == cmd) {
245 switch ((*o)->state) {
246 case REQUESTED:
247 (*o)->state = ACTIVE;
248 activate_option (*o);
249 break;
250 case ACTIVE:
251 break;
252 case INACTIVE:
253 (*o)->state = ACTIVE;
254 send_opt ((*o)->send, option);
255 activate_option (*o);
256 break;
257 case REALLY_INACTIVE:
258 send_opt ((*o)->nsend, option);
259 break;
260 }
261 return;
262 } else if ((*o)->option == option && (*o)->nak == cmd) {
263 switch ((*o)->state) {
264 case REQUESTED:
265 (*o)->state = INACTIVE;
266 refused_option (*o);
267 break;
268 case ACTIVE:
269 (*o)->state = INACTIVE;
270 send_opt ((*o)->nsend, option);
271 break;
272 case INACTIVE:
273 case REALLY_INACTIVE:
274 break;
275 }
276 return;
277 }
278 }
279 /*
280 * If we reach here, the option was one we weren't prepared to
281 * cope with. So send a negative ack.
282 */
283 send_opt ((cmd == WILL ? DONT : WONT), option);
284 }
285
286 static void process_subneg (void) {
287 unsigned char b[2048], *p, *q;
288 int var, value, n;
289 char *e;
290
291 switch (sb_opt) {
292 case TELOPT_TSPEED:
293 if (sb_len == 1 && sb_buf[0] == TELQUAL_SEND) {
294 char logbuf[sizeof(cfg.termspeed)+80];
295 b[0] = IAC; b[1] = SB; b[2] = TELOPT_TSPEED;
296 b[3] = TELQUAL_IS;
297 strcpy(b+4, cfg.termspeed);
298 n = 4 + strlen(cfg.termspeed);
299 b[n] = IAC; b[n+1] = SE;
300 s_write (b, n+2);
301 logevent("server:\tSB TSPEED SEND");
302 sprintf(logbuf, "client:\tSB TSPEED IS %s", cfg.termspeed);
303 logevent (logbuf);
304 } else
305 logevent ("server:\tSB TSPEED <something weird>");
306 break;
307 case TELOPT_TTYPE:
308 if (sb_len == 1 && sb_buf[0] == TELQUAL_SEND) {
309 char logbuf[sizeof(cfg.termtype)+80];
310 b[0] = IAC; b[1] = SB; b[2] = TELOPT_TTYPE;
311 b[3] = TELQUAL_IS;
312 for (n = 0; cfg.termtype[n]; n++)
313 b[n+4] = (cfg.termtype[n] >= 'a' && cfg.termtype[n] <= 'z' ?
314 cfg.termtype[n] + 'A'-'a' : cfg.termtype[n]);
315 b[n+4] = IAC; b[n+5] = SE;
316 s_write (b, n+6);
317 b[n+4] = 0;
318 logevent("server:\tSB TTYPE SEND");
319 sprintf(logbuf, "client:\tSB TTYPE IS %s", b+4);
320 logevent(logbuf);
321 } else
322 logevent("server:\tSB TTYPE <something weird>\r\n");
323 break;
324 case TELOPT_OLD_ENVIRON:
325 case TELOPT_NEW_ENVIRON:
326 p = sb_buf;
327 q = p + sb_len;
328 if (p < q && *p == TELQUAL_SEND) {
329 char logbuf[50];
330 p++;
331 sprintf (logbuf, "server:\tSB %s SEND", telopt(sb_opt));
332 logevent (logbuf);
333 if (sb_opt == TELOPT_OLD_ENVIRON) {
334 if (cfg.rfc_environ) {
335 value = RFC_VALUE;
336 var = RFC_VAR;
337 } else {
338 value = BSD_VALUE;
339 var = BSD_VAR;
340 }
341 /*
342 * Try to guess the sense of VAR and VALUE.
343 */
344 while (p < q) {
345 if (*p == RFC_VAR) {
346 value = RFC_VALUE;
347 var = RFC_VAR;
348 } else if (*p == BSD_VAR) {
349 value = BSD_VALUE;
350 var = BSD_VAR;
351 }
352 p++;
353 }
354 } else {
355 /*
356 * With NEW_ENVIRON, the sense of VAR and VALUE
357 * isn't in doubt.
358 */
359 value = RFC_VALUE;
360 var = RFC_VAR;
361 }
362 b[0] = IAC; b[1] = SB; b[2] = sb_opt;
363 b[3] = TELQUAL_IS;
364 n = 4;
365 e = cfg.environmt;
366 while (*e) {
367 b[n++] = var;
368 while (*e && *e != '\t') b[n++] = *e++;
369 if (*e == '\t') e++;
370 b[n++] = value;
371 while (*e) b[n++] = *e++;
372 e++;
373 }
374 if (*cfg.username) {
375 b[n++] = var; b[n++] = 'U'; b[n++] = 'S';
376 b[n++] = 'E'; b[n++] = 'R'; b[n++] = value;
377 e = cfg.username;
378 while (*e) b[n++] = *e++;
379 }
380 b[n++] = IAC; b[n++] = SE;
381 s_write (b, n);
382 sprintf(logbuf, "client:\tSB %s IS %s", telopt(sb_opt),
383 n==6 ? "<nothing>" : "<stuff>");
384 logevent (logbuf);
385 }
386 break;
387 }
388 }
389
390 static enum {
391 TOPLEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
392 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
393 } telnet_state = TOPLEVEL;
394
395 static void do_telnet_read (char *buf, int len) {
396 unsigned char b[10];
397
398 while (len--) {
399 int c = (unsigned char) *buf++;
400
401 switch (telnet_state) {
402 case TOPLEVEL:
403 case SEENCR:
404 if (c == NUL && telnet_state == SEENCR)
405 telnet_state = TOPLEVEL;
406 else if (c == IAC)
407 telnet_state = SEENIAC;
408 else {
409 b[0] = c;
410 #if 0
411 if (!in_synch)
412 #endif
413 c_write (b, 1);
414 if (c == CR)
415 telnet_state = SEENCR;
416 else
417 telnet_state = TOPLEVEL;
418 }
419 break;
420 case SEENIAC:
421 if (c == DO) telnet_state = SEENDO;
422 else if (c == DONT) telnet_state = SEENDONT;
423 else if (c == WILL) telnet_state = SEENWILL;
424 else if (c == WONT) telnet_state = SEENWONT;
425 else if (c == SB) telnet_state = SEENSB;
426 else {
427 /* ignore everything else; print it if it's IAC */
428 if (c == IAC) {
429 b[0] = c;
430 c_write(b,1);
431 }
432 telnet_state = TOPLEVEL;
433 }
434 break;
435 case SEENWILL:
436 proc_rec_opt (WILL, c);
437 telnet_state = TOPLEVEL;
438 break;
439 case SEENWONT:
440 proc_rec_opt (WONT, c);
441 telnet_state = TOPLEVEL;
442 break;
443 case SEENDO:
444 proc_rec_opt (DO, c);
445 telnet_state = TOPLEVEL;
446 break;
447 case SEENDONT:
448 proc_rec_opt (DONT, c);
449 telnet_state = TOPLEVEL;
450 break;
451 case SEENSB:
452 sb_opt = c;
453 sb_len = 0;
454 telnet_state = SUBNEGOT;
455 break;
456 case SUBNEGOT:
457 if (c == IAC)
458 telnet_state = SUBNEG_IAC;
459 else {
460 subneg_addchar:
461 if (sb_len >= sb_size) {
462 char *newbuf;
463 sb_size += SB_DELTA;
464 newbuf = (sb_buf ?
465 realloc(sb_buf, sb_size) :
466 malloc(sb_size));
467 if (newbuf)
468 sb_buf = newbuf;
469 else
470 sb_size -= SB_DELTA;
471 }
472 if (sb_len < sb_size)
473 sb_buf[sb_len++] = c;
474 telnet_state = SUBNEGOT;/* in case we came here by goto */
475 }
476 break;
477 case SUBNEG_IAC:
478 if (c != SE)
479 goto subneg_addchar; /* yes, it's a hack, I know, but... */
480 else {
481 process_subneg();
482 telnet_state = TOPLEVEL;
483 }
484 break;
485 }
486 }
487 }
488
489 /*
490 * Called to set up the Telnet connection. Will arrange for
491 * WM_NETEVENT messages to be passed to the specified window, whose
492 * window procedure should then call telnet_msg().
493 *
494 * Returns an error message, or NULL on success.
495 *
496 * Also places the canonical host name into `realhost'.
497 */
498 static char *telnet_init (HWND hwnd, char *host, int port, char **realhost) {
499 SOCKADDR_IN addr;
500 struct hostent *h;
501 unsigned long a;
502
503 /*
504 * Try to find host.
505 */
506 if ( (a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
507 if ( (h = gethostbyname(host)) == NULL)
508 switch (WSAGetLastError()) {
509 case WSAENETDOWN: return "Network is down";
510 case WSAHOST_NOT_FOUND: case WSANO_DATA:
511 return "Host does not exist";
512 case WSATRY_AGAIN: return "Host not found";
513 default: return "gethostbyname: unknown error";
514 }
515 memcpy (&a, h->h_addr, sizeof(a));
516 *realhost = h->h_name;
517 } else
518 *realhost = host;
519 a = ntohl(a);
520
521 if (port < 0)
522 port = 23; /* default telnet port */
523
524 /*
525 * Open socket.
526 */
527 s = socket(AF_INET, SOCK_STREAM, 0);
528 if (s == INVALID_SOCKET)
529 switch (WSAGetLastError()) {
530 case WSAENETDOWN: return "Network is down";
531 case WSAEAFNOSUPPORT: return "TCP/IP support not present";
532 default: return "socket(): unknown error";
533 }
534
535 #if 0
536 {
537 BOOL b = TRUE;
538 setsockopt (s, SOL_SOCKET, SO_OOBINLINE, (void *)&b, sizeof(b));
539 }
540 #endif
541
542 /*
543 * Bind to local address.
544 */
545 addr.sin_family = AF_INET;
546 addr.sin_addr.s_addr = htonl(INADDR_ANY);
547 addr.sin_port = htons(0);
548 if (bind (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
549 switch (WSAGetLastError()) {
550 case WSAENETDOWN: return "Network is down";
551 default: return "bind(): unknown error";
552 }
553
554 /*
555 * Connect to remote address.
556 */
557 addr.sin_addr.s_addr = htonl(a);
558 addr.sin_port = htons((short)port);
559 if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
560 switch (WSAGetLastError()) {
561 case WSAENETDOWN: return "Network is down";
562 case WSAECONNREFUSED: return "Connection refused";
563 case WSAENETUNREACH: return "Network is unreachable";
564 case WSAEHOSTUNREACH: return "No route to host";
565 default: return "connect(): unknown error";
566 }
567
568 if (WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ |
569 FD_WRITE | FD_OOB | FD_CLOSE) == SOCKET_ERROR)
570 switch (WSAGetLastError()) {
571 case WSAENETDOWN: return "Network is down";
572 default: return "WSAAsyncSelect(): unknown error";
573 }
574
575 /*
576 * Initialise option states.
577 */
578 {
579 struct Opt **o;
580
581 for (o = opts; *o; o++)
582 if ((*o)->state == REQUESTED)
583 send_opt ((*o)->send, (*o)->option);
584 }
585
586 #if 0
587 /*
588 * Set up SYNCH state.
589 */
590 in_synch = FALSE;
591 #endif
592
593 return NULL;
594 }
595
596 /*
597 * Process a WM_NETEVENT message. Will return 0 if the connection
598 * has closed, or <0 for a socket error.
599 */
600 static int telnet_msg (WPARAM wParam, LPARAM lParam) {
601 int ret;
602 char buf[256];
603
604 /*
605 * Because reading less than the whole of the available pending
606 * data can generate an FD_READ event, we need to allow for the
607 * possibility that FD_READ may arrive with FD_CLOSE already in
608 * the queue; so it's possible that we can get here even with s
609 * invalid. If so, we return 1 and don't worry about it.
610 */
611 if (s == INVALID_SOCKET)
612 return 1;
613
614 if (WSAGETSELECTERROR(lParam) != 0)
615 return -WSAGETSELECTERROR(lParam);
616
617 switch (WSAGETSELECTEVENT(lParam)) {
618 case FD_READ:
619 case FD_CLOSE:
620 ret = recv(s, buf, sizeof(buf), 0);
621 if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK)
622 return 1;
623 if (ret < 0) /* any _other_ error */
624 return -10000-WSAGetLastError();
625 if (ret == 0) {
626 s = INVALID_SOCKET;
627 return 0;
628 }
629 #if 0
630 if (in_synch) {
631 BOOL i;
632 if (ioctlsocket (s, SIOCATMARK, &i) < 0) {
633 return -20000-WSAGetLastError();
634 }
635 if (i)
636 in_synch = FALSE;
637 }
638 #endif
639 do_telnet_read (buf, ret);
640 return 1;
641 case FD_OOB:
642 do {
643 ret = recv(s, buf, sizeof(buf), 0);
644 } while (ret > 0);
645 telnet_state = TOPLEVEL;
646 do {
647 ret = recv(s, buf, 1, MSG_OOB);
648 if (ret > 0)
649 do_telnet_read (buf, ret);
650 } while (ret > 0);
651 if (ret < 0 && WSAGetLastError() != WSAEWOULDBLOCK)
652 return -30000-WSAGetLastError();
653 return 1;
654 case FD_WRITE:
655 if (outbuf_head != outbuf_reap)
656 try_write();
657 return 1;
658 }
659 return 1; /* shouldn't happen, but WTF */
660 }
661
662 /*
663 * Called to send data down the Telnet connection.
664 */
665 static void telnet_send (char *buf, int len) {
666 char *p;
667 static unsigned char iac[2] = { IAC, IAC };
668 static unsigned char cr[2] = { CR, NUL };
669
670 if (s == INVALID_SOCKET)
671 return;
672
673 p = buf;
674 while (p < buf+len) {
675 char *q = p;
676
677 while (iswritable((unsigned char)*p) && p < buf+len) p++;
678 s_write (q, p-q);
679
680 while (p < buf+len && !iswritable((unsigned char)*p)) {
681 s_write ((unsigned char)*p == IAC ? iac : cr, 2);
682 p++;
683 }
684 }
685 }
686
687 /*
688 * Called to set the size of the window from Telnet's POV.
689 */
690 static void telnet_size(void) {
691 unsigned char b[16];
692 char logbuf[50];
693
694 if (s == INVALID_SOCKET || o_naws.state != ACTIVE)
695 return;
696 b[0] = IAC; b[1] = SB; b[2] = TELOPT_NAWS;
697 b[3] = cols >> 8; b[4] = cols & 0xFF;
698 b[5] = rows >> 8; b[6] = rows & 0xFF;
699 b[7] = IAC; b[8] = SE;
700 s_write (b, 9);
701 sprintf(logbuf, "client:\tSB NAWS %d,%d",
702 ((unsigned char)b[3] << 8) + (unsigned char)b[4],
703 ((unsigned char)b[5] << 8) + (unsigned char)b[6]);
704 logevent (logbuf);
705 }
706
707 /*
708 * Send Telnet special codes.
709 */
710 static void telnet_special (Telnet_Special code) {
711 unsigned char b[2];
712
713 if (s == INVALID_SOCKET)
714 return;
715
716 b[0] = IAC;
717 switch (code) {
718 case TS_AYT: b[1] = AYT; s_write (b, 2); break;
719 case TS_BRK: b[1] = BREAK; s_write (b, 2); break;
720 case TS_EC: b[1] = EC; s_write (b, 2); break;
721 case TS_EL: b[1] = EL; s_write (b, 2); break;
722 case TS_GA: b[1] = GA; s_write (b, 2); break;
723 case TS_NOP: b[1] = NOP; s_write (b, 2); break;
724 case TS_ABORT: b[1] = ABORT; s_write (b, 2); break;
725 case TS_AO: b[1] = AO; s_write (b, 2); break;
726 case TS_IP: b[1] = IP; s_write (b, 2); break;
727 case TS_SUSP: b[1] = SUSP; s_write (b, 2); break;
728 case TS_EOR: b[1] = EOR; s_write (b, 2); break;
729 case TS_EOF: b[1] = xEOF; s_write (b, 2); break;
730 case TS_SYNCH:
731 outbuf_head = outbuf_reap = 0;
732 b[1] = DM;
733 send (s, b, 2, MSG_OOB);
734 break;
735 case TS_RECHO:
736 if (o_echo.state == INACTIVE || o_echo.state == REALLY_INACTIVE) {
737 o_echo.state = REQUESTED;
738 send_opt (o_echo.send, o_echo.option);
739 }
740 break;
741 case TS_LECHO:
742 if (o_echo.state == ACTIVE) {
743 o_echo.state = REQUESTED;
744 send_opt (o_echo.nsend, o_echo.option);
745 }
746 break;
747 }
748 }
749
750 Backend telnet_backend = {
751 telnet_init,
752 telnet_msg,
753 telnet_send,
754 telnet_size,
755 telnet_special
756 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator