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Prevent network errors from summarily closing the window when CoE is off
[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 static int in_synch;
137 static int sb_opt, sb_len;
138 static char *sb_buf = NULL;
139 static int sb_size = 0;
140 #define SB_DELTA 1024
141
142 static void try_write (void) {
143 while (outbuf_head != outbuf_reap) {
144 int end = (outbuf_reap < outbuf_head ? outbuf_head : OUTBUF_SIZE);
145 int len = end - outbuf_reap;
146 int ret;
147
148 ret = send (s, outbuf+outbuf_reap, len, 0);
149 if (ret > 0)
150 outbuf_reap = (outbuf_reap + ret) & OUTBUF_MASK;
151 if (ret < len)
152 return;
153 }
154 }
155
156 static void s_write (void *buf, int len) {
157 unsigned char *p = buf;
158 while (len--) {
159 int new_head = (outbuf_head + 1) & OUTBUF_MASK;
160 if (new_head != outbuf_reap) {
161 outbuf[outbuf_head] = *p++;
162 outbuf_head = new_head;
163 }
164 }
165 try_write();
166 }
167
168 static void log_option (char *sender, int cmd, int option) {
169 char buf[50];
170 sprintf(buf, "%s:\t%s %s", sender,
171 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
172 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<??>"),
173 telopt(option));
174 logevent(buf);
175 }
176
177 static void send_opt (int cmd, int option) {
178 unsigned char b[3];
179
180 b[0] = IAC; b[1] = cmd; b[2] = option;
181 s_write (b, 3);
182 log_option("client", cmd, option);
183 }
184
185 static void deactivate_option (struct Opt *o) {
186 if (o->state == REQUESTED || o->state == ACTIVE)
187 send_opt (o->nsend, o->option);
188 o->state = REALLY_INACTIVE;
189 }
190
191 static void activate_option (struct Opt *o) {
192 if (o->send == WILL && o->option == TELOPT_NAWS)
193 telnet_size();
194 if (o->send == WILL &&
195 (o->option == TELOPT_NEW_ENVIRON ||
196 o->option == TELOPT_OLD_ENVIRON)) {
197 /*
198 * We may only have one kind of ENVIRON going at a time.
199 * This is a hack, but who cares.
200 */
201 deactivate_option (o->option==TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
202 }
203 if (o->option == TELOPT_ECHO && cfg.ldisc_term)
204 ldisc = &ldisc_simple;
205 }
206
207 static void refused_option (struct Opt *o) {
208 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
209 o_oenv.state == INACTIVE) {
210 send_opt (WILL, TELOPT_OLD_ENVIRON);
211 o_oenv.state = REQUESTED;
212 }
213 if (o->option == TELOPT_ECHO && cfg.ldisc_term)
214 ldisc = &ldisc_term;
215 }
216
217 static void proc_rec_opt (int cmd, int option) {
218 struct Opt **o;
219
220 log_option ("server", cmd, option);
221 for (o = opts; *o; o++) {
222 if ((*o)->option == option && (*o)->ack == cmd) {
223 switch ((*o)->state) {
224 case REQUESTED:
225 (*o)->state = ACTIVE;
226 activate_option (*o);
227 break;
228 case ACTIVE:
229 break;
230 case INACTIVE:
231 (*o)->state = ACTIVE;
232 send_opt ((*o)->send, option);
233 activate_option (*o);
234 break;
235 case REALLY_INACTIVE:
236 send_opt ((*o)->nsend, option);
237 break;
238 }
239 return;
240 } else if ((*o)->option == option && (*o)->nak == cmd) {
241 switch ((*o)->state) {
242 case REQUESTED:
243 (*o)->state = INACTIVE;
244 refused_option (*o);
245 break;
246 case ACTIVE:
247 (*o)->state = INACTIVE;
248 send_opt ((*o)->nsend, option);
249 break;
250 case INACTIVE:
251 case REALLY_INACTIVE:
252 break;
253 }
254 return;
255 }
256 }
257 /*
258 * If we reach here, the option was one we weren't prepared to
259 * cope with. So send a negative ack.
260 */
261 send_opt ((cmd == WILL ? DONT : WONT), option);
262 }
263
264 static void process_subneg (void) {
265 unsigned char b[2048], *p, *q;
266 int var, value, n;
267 char *e;
268
269 switch (sb_opt) {
270 case TELOPT_TSPEED:
271 if (sb_len == 1 && sb_buf[0] == TELQUAL_SEND) {
272 char logbuf[sizeof(cfg.termspeed)+80];
273 b[0] = IAC; b[1] = SB; b[2] = TELOPT_TSPEED;
274 b[3] = TELQUAL_IS;
275 strcpy(b+4, cfg.termspeed);
276 n = 4 + strlen(cfg.termspeed);
277 b[n] = IAC; b[n+1] = SE;
278 s_write (b, n+2);
279 logevent("server:\tSB TSPEED SEND");
280 sprintf(logbuf, "client:\tSB TSPEED IS %s", cfg.termspeed);
281 logevent (logbuf);
282 } else
283 logevent ("server:\tSB TSPEED <something weird>");
284 break;
285 case TELOPT_TTYPE:
286 if (sb_len == 1 && sb_buf[0] == TELQUAL_SEND) {
287 char logbuf[sizeof(cfg.termtype)+80];
288 b[0] = IAC; b[1] = SB; b[2] = TELOPT_TTYPE;
289 b[3] = TELQUAL_IS;
290 for (n = 0; cfg.termtype[n]; n++)
291 b[n+4] = (cfg.termtype[n] >= 'a' && cfg.termtype[n] <= 'z' ?
292 cfg.termtype[n] + 'A'-'a' : cfg.termtype[n]);
293 b[n+4] = IAC; b[n+5] = SE;
294 s_write (b, n+6);
295 b[n+4] = 0;
296 logevent("server:\tSB TTYPE SEND");
297 sprintf(logbuf, "client:\tSB TTYPE IS %s", b+4);
298 logevent(logbuf);
299 } else
300 logevent("server:\tSB TTYPE <something weird>\r\n");
301 break;
302 case TELOPT_OLD_ENVIRON:
303 case TELOPT_NEW_ENVIRON:
304 p = sb_buf;
305 q = p + sb_len;
306 if (p < q && *p == TELQUAL_SEND) {
307 char logbuf[50];
308 p++;
309 sprintf (logbuf, "server:\tSB %s SEND", telopt(sb_opt));
310 logevent (logbuf);
311 if (sb_opt == TELOPT_OLD_ENVIRON) {
312 if (cfg.rfc_environ) {
313 value = RFC_VALUE;
314 var = RFC_VAR;
315 } else {
316 value = BSD_VALUE;
317 var = BSD_VAR;
318 }
319 /*
320 * Try to guess the sense of VAR and VALUE.
321 */
322 while (p < q) {
323 if (*p == RFC_VAR) {
324 value = RFC_VALUE;
325 var = RFC_VAR;
326 } else if (*p == BSD_VAR) {
327 value = BSD_VALUE;
328 var = BSD_VAR;
329 }
330 p++;
331 }
332 } else {
333 /*
334 * With NEW_ENVIRON, the sense of VAR and VALUE
335 * isn't in doubt.
336 */
337 value = RFC_VALUE;
338 var = RFC_VAR;
339 }
340 b[0] = IAC; b[1] = SB; b[2] = sb_opt;
341 b[3] = TELQUAL_IS;
342 n = 4;
343 e = cfg.environmt;
344 while (*e) {
345 b[n++] = var;
346 while (*e && *e != '\t') b[n++] = *e++;
347 if (*e == '\t') e++;
348 b[n++] = value;
349 while (*e) b[n++] = *e++;
350 e++;
351 }
352 if (*cfg.username) {
353 b[n++] = var; b[n++] = 'U'; b[n++] = 'S';
354 b[n++] = 'E'; b[n++] = 'R'; b[n++] = value;
355 e = cfg.username;
356 while (*e) b[n++] = *e++;
357 }
358 b[n++] = IAC; b[n++] = SE;
359 s_write (b, n);
360 sprintf(logbuf, "client:\tSB %s IS %s", telopt(sb_opt),
361 n==6 ? "<nothing>" : "<stuff>");
362 logevent (logbuf);
363 }
364 break;
365 }
366 }
367
368 static enum {
369 TOPLEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
370 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
371 } telnet_state = TOPLEVEL;
372
373 static void do_telnet_read (char *buf, int len) {
374
375 while (len--) {
376 int c = (unsigned char) *buf++;
377
378 switch (telnet_state) {
379 case TOPLEVEL:
380 case SEENCR:
381 if (c == NUL && telnet_state == SEENCR)
382 telnet_state = TOPLEVEL;
383 else if (c == IAC)
384 telnet_state = SEENIAC;
385 else {
386 if (!in_synch)
387 c_write1(c);
388
389 #if 1
390 /* I can't get the F***ing winsock to insert the urgent IAC
391 * into the right position! Even with SO_OOBINLINE it gives
392 * it to recv too soon. And of course the DM byte (that
393 * arrives in the same packet!) appears several K later!!
394 *
395 * Oh well, we do get the DM in the right place so I'll
396 * just stop hiding on the next 0xf2 and hope for the best.
397 */
398 else if (c == DM) in_synch = 0;
399 #endif
400 if (c == CR)
401 telnet_state = SEENCR;
402 else
403 telnet_state = TOPLEVEL;
404 }
405 break;
406 case SEENIAC:
407 if (c == DO) telnet_state = SEENDO;
408 else if (c == DONT) telnet_state = SEENDONT;
409 else if (c == WILL) telnet_state = SEENWILL;
410 else if (c == WONT) telnet_state = SEENWONT;
411 else if (c == SB) telnet_state = SEENSB;
412 else if (c == DM) {
413 in_synch = 0;
414 telnet_state = TOPLEVEL;
415 }
416 else {
417 /* ignore everything else; print it if it's IAC */
418 if (c == IAC) {
419 c_write1(c);
420 }
421 telnet_state = TOPLEVEL;
422 }
423 break;
424 case SEENWILL:
425 proc_rec_opt (WILL, c);
426 telnet_state = TOPLEVEL;
427 break;
428 case SEENWONT:
429 proc_rec_opt (WONT, c);
430 telnet_state = TOPLEVEL;
431 break;
432 case SEENDO:
433 proc_rec_opt (DO, c);
434 telnet_state = TOPLEVEL;
435 break;
436 case SEENDONT:
437 proc_rec_opt (DONT, c);
438 telnet_state = TOPLEVEL;
439 break;
440 case SEENSB:
441 sb_opt = c;
442 sb_len = 0;
443 telnet_state = SUBNEGOT;
444 break;
445 case SUBNEGOT:
446 if (c == IAC)
447 telnet_state = SUBNEG_IAC;
448 else {
449 subneg_addchar:
450 if (sb_len >= sb_size) {
451 char *newbuf;
452 sb_size += SB_DELTA;
453 newbuf = (sb_buf ?
454 srealloc(sb_buf, sb_size) :
455 smalloc(sb_size));
456 if (newbuf)
457 sb_buf = newbuf;
458 else
459 sb_size -= SB_DELTA;
460 }
461 if (sb_len < sb_size)
462 sb_buf[sb_len++] = c;
463 telnet_state = SUBNEGOT;/* in case we came here by goto */
464 }
465 break;
466 case SUBNEG_IAC:
467 if (c != SE)
468 goto subneg_addchar; /* yes, it's a hack, I know, but... */
469 else {
470 process_subneg();
471 telnet_state = TOPLEVEL;
472 }
473 break;
474 }
475 }
476 }
477
478 /*
479 * Called to set up the Telnet connection. Will arrange for
480 * WM_NETEVENT messages to be passed to the specified window, whose
481 * window procedure should then call telnet_msg().
482 *
483 * Returns an error message, or NULL on success.
484 *
485 * Also places the canonical host name into `realhost'.
486 */
487 static char *telnet_init (HWND hwnd, char *host, int port, char **realhost) {
488 SOCKADDR_IN addr;
489 struct hostent *h;
490 unsigned long a;
491
492 /*
493 * Try to find host.
494 */
495 if ( (a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
496 if ( (h = gethostbyname(host)) == NULL)
497 switch (WSAGetLastError()) {
498 case WSAENETDOWN: return "Network is down";
499 case WSAHOST_NOT_FOUND: case WSANO_DATA:
500 return "Host does not exist";
501 case WSATRY_AGAIN: return "Host not found";
502 default: return "gethostbyname: unknown error";
503 }
504 memcpy (&a, h->h_addr, sizeof(a));
505 *realhost = h->h_name;
506 } else
507 *realhost = host;
508 a = ntohl(a);
509
510 if (port < 0)
511 port = 23; /* default telnet port */
512
513 /*
514 * Open socket.
515 */
516 s = socket(AF_INET, SOCK_STREAM, 0);
517 if (s == INVALID_SOCKET)
518 switch (WSAGetLastError()) {
519 case WSAENETDOWN: return "Network is down";
520 case WSAEAFNOSUPPORT: return "TCP/IP support not present";
521 default: return "socket(): unknown error";
522 }
523
524 {
525 BOOL b = TRUE;
526 setsockopt (s, SOL_SOCKET, SO_OOBINLINE, (void *)&b, sizeof(b));
527 }
528
529 /*
530 * Bind to local address.
531 */
532 addr.sin_family = AF_INET;
533 addr.sin_addr.s_addr = htonl(INADDR_ANY);
534 addr.sin_port = htons(0);
535 if (bind (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
536 switch (WSAGetLastError()) {
537 case WSAENETDOWN: return "Network is down";
538 default: return "bind(): unknown error";
539 }
540
541 /*
542 * Connect to remote address.
543 */
544 addr.sin_addr.s_addr = htonl(a);
545 addr.sin_port = htons((short)port);
546 if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
547 switch (WSAGetLastError()) {
548 case WSAENETDOWN: return "Network is down";
549 case WSAECONNREFUSED: return "Connection refused";
550 case WSAENETUNREACH: return "Network is unreachable";
551 case WSAEHOSTUNREACH: return "No route to host";
552 default: return "connect(): unknown error";
553 }
554
555 if (hwnd && WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ |
556 FD_WRITE | FD_OOB | FD_CLOSE) == SOCKET_ERROR)
557 switch (WSAGetLastError()) {
558 case WSAENETDOWN: return "Network is down";
559 default: return "WSAAsyncSelect(): unknown error";
560 }
561
562 /*
563 * Initialise option states.
564 */
565 if( cfg.ldisc_term )
566 {
567 struct Opt **o;
568
569 for (o = opts; *o; o++)
570 if ((*o)->state == REQUESTED)
571 (*o)->state = INACTIVE;
572 }
573 else
574 {
575 struct Opt **o;
576
577 for (o = opts; *o; o++)
578 if ((*o)->state == REQUESTED)
579 send_opt ((*o)->send, (*o)->option);
580 }
581
582 /*
583 * Set up SYNCH state.
584 */
585 in_synch = FALSE;
586 return NULL;
587 }
588
589 /*
590 * Process a WM_NETEVENT message. Will return 0 if the connection
591 * has closed, or <0 for a socket error.
592 */
593 static int telnet_msg (WPARAM wParam, LPARAM lParam) {
594 int ret;
595 /* This needs to be larger than the packet size now that inbuf
596 * cannot overflow, in fact the fewer calls we make to windows
597 * the faster we will run!
598 */
599 char buf[16384];
600
601 /*
602 * Because reading less than the whole of the available pending
603 * data can generate an FD_READ event, we need to allow for the
604 * possibility that FD_READ may arrive with FD_CLOSE already in
605 * the queue; so it's possible that we can get here even with s
606 * invalid. If so, we return 1 and don't worry about it.
607 */
608 if (s == INVALID_SOCKET)
609 return 1;
610
611 if (WSAGETSELECTERROR(lParam) != 0) {
612 closesocket(s);
613 s = INVALID_SOCKET;
614 return -WSAGETSELECTERROR(lParam);
615 }
616
617 switch (WSAGETSELECTEVENT(lParam)) {
618 case FD_READ:
619 case FD_CLOSE:
620 {
621 int clear_of_oob = 1;
622 if (ioctlsocket (s, SIOCATMARK, &clear_of_oob) < 0 )
623 return -20000-WSAGetLastError();
624
625 in_synch = !clear_of_oob;
626
627 do {
628 ret = recv(s, buf, sizeof(buf), 0);
629 if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK)
630 return 1;
631 if (ret < 0) { /* any _other_ error */
632 closesocket(s);
633 s = INVALID_SOCKET;
634 return -10000-WSAGetLastError();
635 }
636 if (ret == 0) {
637 s = INVALID_SOCKET;
638 return 0;
639 }
640 do_telnet_read (buf, ret);
641 } while (in_synch);
642 }
643 return 1;
644 case FD_WRITE:
645 if (outbuf_head != outbuf_reap)
646 try_write();
647 return 1;
648 }
649 return 1; /* shouldn't happen, but WTF */
650 }
651
652 /*
653 * Called to send data down the Telnet connection.
654 */
655 static void telnet_send (char *buf, int len) {
656 char *p;
657 static unsigned char iac[2] = { IAC, IAC };
658 static unsigned char cr[2] = { CR, NUL };
659 static unsigned char nl[2] = { CR, LF };
660
661 if (s == INVALID_SOCKET)
662 return;
663
664 p = buf;
665 while (p < buf+len) {
666 char *q = p;
667
668 while (iswritable((unsigned char)*p) && p < buf+len) p++;
669 s_write (q, p-q);
670
671 while (p < buf+len && !iswritable((unsigned char)*p)) {
672 s_write ((unsigned char)*p == IAC ? iac : nl, 2);
673 p++;
674 }
675 }
676 }
677
678 /*
679 * Called to set the size of the window from Telnet's POV.
680 */
681 static void telnet_size(void) {
682 unsigned char b[16];
683 char logbuf[50];
684
685 if (s == INVALID_SOCKET || o_naws.state != ACTIVE)
686 return;
687 b[0] = IAC; b[1] = SB; b[2] = TELOPT_NAWS;
688 b[3] = cols >> 8; b[4] = cols & 0xFF;
689 b[5] = rows >> 8; b[6] = rows & 0xFF;
690 b[7] = IAC; b[8] = SE;
691 s_write (b, 9);
692 sprintf(logbuf, "client:\tSB NAWS %d,%d",
693 ((unsigned char)b[3] << 8) + (unsigned char)b[4],
694 ((unsigned char)b[5] << 8) + (unsigned char)b[6]);
695 logevent (logbuf);
696 }
697
698 /*
699 * Send Telnet special codes.
700 */
701 static void telnet_special (Telnet_Special code) {
702 unsigned char b[2];
703
704 if (s == INVALID_SOCKET)
705 return;
706
707 b[0] = IAC;
708 switch (code) {
709 case TS_AYT: b[1] = AYT; s_write (b, 2); break;
710 case TS_BRK: b[1] = BREAK; s_write (b, 2); break;
711 case TS_EC: b[1] = EC; s_write (b, 2); break;
712 case TS_EL: b[1] = EL; s_write (b, 2); break;
713 case TS_GA: b[1] = GA; s_write (b, 2); break;
714 case TS_NOP: b[1] = NOP; s_write (b, 2); break;
715 case TS_ABORT: b[1] = ABORT; s_write (b, 2); break;
716 case TS_AO: b[1] = AO; s_write (b, 2); break;
717 case TS_IP: b[1] = IP; s_write (b, 2); break;
718 case TS_SUSP: b[1] = SUSP; s_write (b, 2); break;
719 case TS_EOR: b[1] = EOR; s_write (b, 2); break;
720 case TS_EOF: b[1] = xEOF; s_write (b, 2); break;
721 case TS_SYNCH:
722 outbuf_head = outbuf_reap = 0;
723 b[1] = DM;
724 send (s, b, 2, MSG_OOB);
725 break;
726 case TS_RECHO:
727 if (o_echo.state == INACTIVE || o_echo.state == REALLY_INACTIVE) {
728 o_echo.state = REQUESTED;
729 send_opt (o_echo.send, o_echo.option);
730 }
731 break;
732 case TS_LECHO:
733 if (o_echo.state == ACTIVE) {
734 o_echo.state = REQUESTED;
735 send_opt (o_echo.nsend, o_echo.option);
736 }
737 break;
738 }
739 }
740
741 static SOCKET telnet_socket(void) { return s; }
742
743 static int telnet_sendok(void) { return 1; }
744
745 Backend telnet_backend = {
746 telnet_init,
747 telnet_msg,
748 telnet_send,
749 telnet_size,
750 telnet_special,
751 telnet_socket,
752 telnet_sendok
753 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator