21 static SOCKET s = INVALID_SOCKET;
23 #define IAC 255 /* interpret as command: */
24 #define DONT 254 /* you are not to use option */
25 #define DO 253 /* please, you use option */
26 #define WONT 252 /* I won't use option */
27 #define WILL 251 /* I will use option */
28 #define SB 250 /* interpret as subnegotiation */
29 #define SE 240 /* end sub negotiation */
31 #define GA 249 /* you may reverse the line */
32 #define EL 248 /* erase the current line */
33 #define EC 247 /* erase the current character */
34 #define AYT 246 /* are you there */
35 #define AO 245 /* abort output--but let prog finish */
36 #define IP 244 /* interrupt process--permanently */
37 #define BREAK 243 /* break */
38 #define DM 242 /* data mark--for connect. cleaning */
39 #define NOP 241 /* nop */
40 #define EOR 239 /* end of record (transparent mode) */
41 #define ABORT 238 /* Abort process */
42 #define SUSP 237 /* Suspend process */
43 #define xEOF 236 /* End of file: EOF is already used... */
45 #define TELOPT_BINARY 0 /* 8-bit data path */
46 #define TELOPT_ECHO 1 /* echo */
47 #define TELOPT_RCP 2 /* prepare to reconnect */
48 #define TELOPT_SGA 3 /* suppress go ahead */
49 #define TELOPT_NAMS 4 /* approximate message size */
50 #define TELOPT_STATUS 5 /* give status */
51 #define TELOPT_TM 6 /* timing mark */
52 #define TELOPT_RCTE 7 /* remote controlled transmission and echo */
53 #define TELOPT_NAOL 8 /* negotiate about output line width */
54 #define TELOPT_NAOP 9 /* negotiate about output page size */
55 #define TELOPT_NAOCRD 10 /* negotiate about CR disposition */
56 #define TELOPT_NAOHTS 11 /* negotiate about horizontal tabstops */
57 #define TELOPT_NAOHTD 12 /* negotiate about horizontal tab disposition */
58 #define TELOPT_NAOFFD 13 /* negotiate about formfeed disposition */
59 #define TELOPT_NAOVTS 14 /* negotiate about vertical tab stops */
60 #define TELOPT_NAOVTD 15 /* negotiate about vertical tab disposition */
61 #define TELOPT_NAOLFD 16 /* negotiate about output LF disposition */
62 #define TELOPT_XASCII 17 /* extended ascic character set */
63 #define TELOPT_LOGOUT 18 /* force logout */
64 #define TELOPT_BM 19 /* byte macro */
65 #define TELOPT_DET 20 /* data entry terminal */
66 #define TELOPT_SUPDUP 21 /* supdup protocol */
67 #define TELOPT_SUPDUPOUTPUT 22 /* supdup output */
68 #define TELOPT_SNDLOC 23 /* send location */
69 #define TELOPT_TTYPE 24 /* terminal type */
70 #define TELOPT_EOR 25 /* end or record */
71 #define TELOPT_TUID 26 /* TACACS user identification */
72 #define TELOPT_OUTMRK 27 /* output marking */
73 #define TELOPT_TTYLOC 28 /* terminal location number */
74 #define TELOPT_3270REGIME 29 /* 3270 regime */
75 #define TELOPT_X3PAD 30 /* X.3 PAD */
76 #define TELOPT_NAWS 31 /* window size */
77 #define TELOPT_TSPEED 32 /* terminal speed */
78 #define TELOPT_LFLOW 33 /* remote flow control */
79 #define TELOPT_LINEMODE 34 /* Linemode option */
80 #define TELOPT_XDISPLOC 35 /* X Display Location */
81 #define TELOPT_OLD_ENVIRON 36 /* Old - Environment variables */
82 #define TELOPT_AUTHENTICATION 37/* Authenticate */
83 #define TELOPT_ENCRYPT 38 /* Encryption option */
84 #define TELOPT_NEW_ENVIRON 39 /* New - Environment variables */
85 #define TELOPT_EXOPL 255 /* extended-options-list */
87 #define TELQUAL_IS 0 /* option is... */
88 #define TELQUAL_SEND 1 /* send option */
89 #define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
99 #define iswritable(x) ( (x) != IAC && (x) != CR )
101 static char *telopt(int opt) {
102 #define i(x) if (opt == TELOPT_ ## x) return #x;
103 i(BINARY); i(ECHO); i(RCP); i(SGA); i(NAMS); i(STATUS); i(TM); i(RCTE);
104 i(NAOL); i(NAOP); i(NAOCRD); i(NAOHTS); i(NAOHTD); i(NAOFFD); i(NAOVTS);
105 i(NAOVTD); i(NAOLFD); i(XASCII); i(LOGOUT); i(BM); i(DET); i(SUPDUP);
106 i(SUPDUPOUTPUT); i(SNDLOC); i(TTYPE); i(EOR); i(TUID); i(OUTMRK);
107 i(TTYLOC); i(X3PAD); i(NAWS); i(TSPEED); i(LFLOW); i(LINEMODE);
108 i(XDISPLOC); i(OLD_ENVIRON); i(AUTHENTICATION); i(ENCRYPT);
109 i(NEW_ENVIRON); i(EXOPL);
114 static void telnet_size(void);
117 int send; /* what we initially send */
118 int nsend; /* -ve send if requested to stop it */
119 int ack, nak; /* +ve and -ve acknowledgements */
120 int option; /* the option code */
122 REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE
126 static struct Opt o_naws = {WILL, WONT, DO, DONT, TELOPT_NAWS, REQUESTED};
127 static struct Opt o_tspeed = {WILL, WONT, DO, DONT, TELOPT_TSPEED, REQUESTED};
128 static struct Opt o_ttype = {WILL, WONT, DO, DONT, TELOPT_TTYPE, REQUESTED};
129 static struct Opt o_oenv = {WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON,
131 static struct Opt o_nenv = {WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON,
133 static struct Opt o_echo = {DO, DONT, WILL, WONT, TELOPT_ECHO, REQUESTED};
134 static struct Opt o_we_sga = {WILL, WONT, DO, DONT, TELOPT_SGA, REQUESTED};
135 static struct Opt o_they_sga = {DO, DONT, WILL, WONT, TELOPT_SGA, REQUESTED};
137 static struct Opt *opts[] = {
138 &o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,
139 &o_we_sga, &o_they_sga, NULL
143 static int sb_opt, sb_len;
144 static char *sb_buf = NULL;
145 static int sb_size = 0;
146 #define SB_DELTA 1024
148 static void try_write (void) {
149 while (outbuf_head != outbuf_reap) {
150 int end = (outbuf_reap < outbuf_head ? outbuf_head : OUTBUF_SIZE);
151 int len = end - outbuf_reap;
154 ret = send (s, outbuf+outbuf_reap, len, 0);
156 outbuf_reap = (outbuf_reap + ret) & OUTBUF_MASK;
162 static void s_write (void *buf, int len) {
163 unsigned char *p = buf;
165 int new_head = (outbuf_head + 1) & OUTBUF_MASK;
166 if (new_head != outbuf_reap) {
167 outbuf[outbuf_head] = *p++;
168 outbuf_head = new_head;
174 static void c_write1(int c) {
176 from_backend(0, &cc, 1);
179 static void log_option (char *sender, int cmd, int option) {
181 sprintf(buf, "%s:\t%s %s", sender,
182 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
183 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<??>"),
188 static void send_opt (int cmd, int option) {
191 b[0] = IAC; b[1] = cmd; b[2] = option;
193 log_option("client", cmd, option);
196 static void deactivate_option (struct Opt *o) {
197 if (o->state == REQUESTED || o->state == ACTIVE)
198 send_opt (o->nsend, o->option);
199 o->state = REALLY_INACTIVE;
202 static void activate_option (struct Opt *o) {
203 if (o->send == WILL && o->option == TELOPT_NAWS)
205 if (o->send == WILL &&
206 (o->option == TELOPT_NEW_ENVIRON ||
207 o->option == TELOPT_OLD_ENVIRON)) {
209 * We may only have one kind of ENVIRON going at a time.
210 * This is a hack, but who cares.
212 deactivate_option (o->option==TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
214 if (o->option == TELOPT_ECHO && cfg.ldisc_term)
215 ldisc = &ldisc_simple;
218 static void refused_option (struct Opt *o) {
219 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
220 o_oenv.state == INACTIVE) {
221 send_opt (WILL, TELOPT_OLD_ENVIRON);
222 o_oenv.state = REQUESTED;
224 if (o->option == TELOPT_ECHO && cfg.ldisc_term)
228 static void proc_rec_opt (int cmd, int option) {
231 log_option ("server", cmd, option);
232 for (o = opts; *o; o++) {
233 if ((*o)->option == option && (*o)->ack == cmd) {
234 switch ((*o)->state) {
236 (*o)->state = ACTIVE;
237 activate_option (*o);
242 (*o)->state = ACTIVE;
243 send_opt ((*o)->send, option);
244 activate_option (*o);
246 case REALLY_INACTIVE:
247 send_opt ((*o)->nsend, option);
251 } else if ((*o)->option == option && (*o)->nak == cmd) {
252 switch ((*o)->state) {
254 (*o)->state = INACTIVE;
258 (*o)->state = INACTIVE;
259 send_opt ((*o)->nsend, option);
262 case REALLY_INACTIVE:
269 * If we reach here, the option was one we weren't prepared to
270 * cope with. So send a negative ack.
272 send_opt ((cmd == WILL ? DONT : WONT), option);
275 static void process_subneg (void) {
276 unsigned char b[2048], *p, *q;
282 if (sb_len == 1 && sb_buf[0] == TELQUAL_SEND) {
283 char logbuf[sizeof(cfg.termspeed)+80];
284 b[0] = IAC; b[1] = SB; b[2] = TELOPT_TSPEED;
286 strcpy(b+4, cfg.termspeed);
287 n = 4 + strlen(cfg.termspeed);
288 b[n] = IAC; b[n+1] = SE;
290 logevent("server:\tSB TSPEED SEND");
291 sprintf(logbuf, "client:\tSB TSPEED IS %s", cfg.termspeed);
294 logevent ("server:\tSB TSPEED <something weird>");
297 if (sb_len == 1 && sb_buf[0] == TELQUAL_SEND) {
298 char logbuf[sizeof(cfg.termtype)+80];
299 b[0] = IAC; b[1] = SB; b[2] = TELOPT_TTYPE;
301 for (n = 0; cfg.termtype[n]; n++)
302 b[n+4] = (cfg.termtype[n] >= 'a' && cfg.termtype[n] <= 'z' ?
303 cfg.termtype[n] + 'A'-'a' : cfg.termtype[n]);
304 b[n+4] = IAC; b[n+5] = SE;
307 logevent("server:\tSB TTYPE SEND");
308 sprintf(logbuf, "client:\tSB TTYPE IS %s", b+4);
311 logevent("server:\tSB TTYPE <something weird>\r\n");
313 case TELOPT_OLD_ENVIRON:
314 case TELOPT_NEW_ENVIRON:
317 if (p < q && *p == TELQUAL_SEND) {
320 sprintf (logbuf, "server:\tSB %s SEND", telopt(sb_opt));
322 if (sb_opt == TELOPT_OLD_ENVIRON) {
323 if (cfg.rfc_environ) {
331 * Try to guess the sense of VAR and VALUE.
337 } else if (*p == BSD_VAR) {
345 * With NEW_ENVIRON, the sense of VAR and VALUE
351 b[0] = IAC; b[1] = SB; b[2] = sb_opt;
357 while (*e && *e != '\t') b[n++] = *e++;
360 while (*e) b[n++] = *e++;
364 b[n++] = var; b[n++] = 'U'; b[n++] = 'S';
365 b[n++] = 'E'; b[n++] = 'R'; b[n++] = value;
367 while (*e) b[n++] = *e++;
369 b[n++] = IAC; b[n++] = SE;
371 sprintf(logbuf, "client:\tSB %s IS %s", telopt(sb_opt),
372 n==6 ? "<nothing>" : "<stuff>");
380 TOPLEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
381 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
382 } telnet_state = TOPLEVEL;
384 static void do_telnet_read (char *buf, int len) {
387 int c = (unsigned char) *buf++;
389 switch (telnet_state) {
392 if (c == NUL && telnet_state == SEENCR)
393 telnet_state = TOPLEVEL;
395 telnet_state = SEENIAC;
401 /* I can't get the F***ing winsock to insert the urgent IAC
402 * into the right position! Even with SO_OOBINLINE it gives
403 * it to recv too soon. And of course the DM byte (that
404 * arrives in the same packet!) appears several K later!!
406 * Oh well, we do get the DM in the right place so I'll
407 * just stop hiding on the next 0xf2 and hope for the best.
409 else if (c == DM) in_synch = 0;
412 telnet_state = SEENCR;
414 telnet_state = TOPLEVEL;
418 if (c == DO) telnet_state = SEENDO;
419 else if (c == DONT) telnet_state = SEENDONT;
420 else if (c == WILL) telnet_state = SEENWILL;
421 else if (c == WONT) telnet_state = SEENWONT;
422 else if (c == SB) telnet_state = SEENSB;
425 telnet_state = TOPLEVEL;
428 /* ignore everything else; print it if it's IAC */
432 telnet_state = TOPLEVEL;
436 proc_rec_opt (WILL, c);
437 telnet_state = TOPLEVEL;
440 proc_rec_opt (WONT, c);
441 telnet_state = TOPLEVEL;
444 proc_rec_opt (DO, c);
445 telnet_state = TOPLEVEL;
448 proc_rec_opt (DONT, c);
449 telnet_state = TOPLEVEL;
454 telnet_state = SUBNEGOT;
458 telnet_state = SUBNEG_IAC;
461 if (sb_len >= sb_size) {
465 srealloc(sb_buf, sb_size) :
472 if (sb_len < sb_size)
473 sb_buf[sb_len++] = c;
474 telnet_state = SUBNEGOT;/* in case we came here by goto */
479 goto subneg_addchar; /* yes, it's a hack, I know, but... */
482 telnet_state = TOPLEVEL;
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().
494 * Returns an error message, or NULL on success.
496 * Also places the canonical host name into `realhost'.
498 static char *telnet_init (HWND hwnd, char *host, int port, char **realhost) {
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";
515 memcpy (&a, h->h_addr, sizeof(a));
516 *realhost = h->h_name;
522 port = 23; /* default telnet port */
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";
537 setsockopt (s, SOL_SOCKET, SO_OOBINLINE, (void *)&b, sizeof(b));
541 * Bind to local address.
543 addr.sin_family = AF_INET;
544 addr.sin_addr.s_addr = htonl(INADDR_ANY);
545 addr.sin_port = htons(0);
546 if (bind (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
547 switch (WSAGetLastError()) {
548 case WSAENETDOWN: return "Network is down";
549 default: return "bind(): unknown error";
553 * Connect to remote address.
555 addr.sin_addr.s_addr = htonl(a);
556 addr.sin_port = htons((short)port);
557 if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
558 switch (WSAGetLastError()) {
559 case WSAENETDOWN: return "Network is down";
560 case WSAECONNREFUSED: return "Connection refused";
561 case WSAENETUNREACH: return "Network is unreachable";
562 case WSAEHOSTUNREACH: return "No route to host";
563 default: return "connect(): unknown error";
566 if (hwnd && WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ |
567 FD_WRITE | FD_OOB | FD_CLOSE) == SOCKET_ERROR)
568 switch (WSAGetLastError()) {
569 case WSAENETDOWN: return "Network is down";
570 default: return "WSAAsyncSelect(): unknown error";
574 * Initialise option states.
580 for (o = opts; *o; o++)
581 if ((*o)->state == REQUESTED)
582 (*o)->state = INACTIVE;
588 for (o = opts; *o; o++)
589 if ((*o)->state == REQUESTED)
590 send_opt ((*o)->send, (*o)->option);
594 * Set up SYNCH state.
599 * We have no pre-session phase.
607 * Process a WM_NETEVENT message. Will return 0 if the connection
608 * has closed, or <0 for a socket error.
610 static int telnet_msg (WPARAM wParam, LPARAM lParam) {
612 /* This needs to be larger than the packet size now that inbuf
613 * cannot overflow, in fact the fewer calls we make to windows
614 * the faster we will run!
619 * Because reading less than the whole of the available pending
620 * data can generate an FD_READ event, we need to allow for the
621 * possibility that FD_READ may arrive with FD_CLOSE already in
622 * the queue; so it's possible that we can get here even with s
623 * invalid. If so, we return 1 and don't worry about it.
625 if (s == INVALID_SOCKET)
628 if (WSAGETSELECTERROR(lParam) != 0) {
631 return -WSAGETSELECTERROR(lParam);
634 switch (WSAGETSELECTEVENT(lParam)) {
638 int clear_of_oob = 1;
640 /* Don't check for error return; some shims don't support
643 ioctlsocket (s, SIOCATMARK, &clear_of_oob);
645 in_synch = !clear_of_oob;
648 ret = recv(s, buf, sizeof(buf), 0);
649 if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK)
651 if (ret < 0) { /* any _other_ error */
654 return -10000-WSAGetLastError();
660 do_telnet_read (buf, ret);
665 if (outbuf_head != outbuf_reap)
669 return 1; /* shouldn't happen, but WTF */
673 * Called to send data down the Telnet connection.
675 static void telnet_send (char *buf, int len) {
677 static unsigned char iac[2] = { IAC, IAC };
678 static unsigned char cr[2] = { CR, NUL };
679 static unsigned char nl[2] = { CR, LF };
681 if (s == INVALID_SOCKET)
685 while (p < buf+len) {
688 while (iswritable((unsigned char)*p) && p < buf+len) p++;
691 while (p < buf+len && !iswritable((unsigned char)*p)) {
692 s_write ((unsigned char)*p == IAC ? iac : nl, 2);
699 * Called to set the size of the window from Telnet's POV.
701 static void telnet_size(void) {
705 if (s == INVALID_SOCKET || o_naws.state != ACTIVE)
707 b[0] = IAC; b[1] = SB; b[2] = TELOPT_NAWS;
708 b[3] = cols >> 8; b[4] = cols & 0xFF;
709 b[5] = rows >> 8; b[6] = rows & 0xFF;
710 b[7] = IAC; b[8] = SE;
712 sprintf(logbuf, "client:\tSB NAWS %d,%d",
713 ((unsigned char)b[3] << 8) + (unsigned char)b[4],
714 ((unsigned char)b[5] << 8) + (unsigned char)b[6]);
719 * Send Telnet special codes.
721 static void telnet_special (Telnet_Special code) {
724 if (s == INVALID_SOCKET)
729 case TS_AYT: b[1] = AYT; s_write (b, 2); break;
730 case TS_BRK: b[1] = BREAK; s_write (b, 2); break;
731 case TS_EC: b[1] = EC; s_write (b, 2); break;
732 case TS_EL: b[1] = EL; s_write (b, 2); break;
733 case TS_GA: b[1] = GA; s_write (b, 2); break;
734 case TS_NOP: b[1] = NOP; s_write (b, 2); break;
735 case TS_ABORT: b[1] = ABORT; s_write (b, 2); break;
736 case TS_AO: b[1] = AO; s_write (b, 2); break;
737 case TS_IP: b[1] = IP; s_write (b, 2); break;
738 case TS_SUSP: b[1] = SUSP; s_write (b, 2); break;
739 case TS_EOR: b[1] = EOR; s_write (b, 2); break;
740 case TS_EOF: b[1] = xEOF; s_write (b, 2); break;
742 outbuf_head = outbuf_reap = 0;
744 send (s, b, 2, MSG_OOB);
747 if (o_echo.state == INACTIVE || o_echo.state == REALLY_INACTIVE) {
748 o_echo.state = REQUESTED;
749 send_opt (o_echo.send, o_echo.option);
753 if (o_echo.state == ACTIVE) {
754 o_echo.state = REQUESTED;
755 send_opt (o_echo.nsend, o_echo.option);
759 if (o_they_sga.state == ACTIVE) {
767 static SOCKET telnet_socket(void) { return s; }
769 static int telnet_sendok(void) { return 1; }
771 Backend telnet_backend = {