15 static SOCKET s = INVALID_SOCKET;
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 */
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... */
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 */
81 #define TELQUAL_IS 0 /* option is... */
82 #define TELQUAL_SEND 1 /* send option */
83 #define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
93 #define iswritable(x) ( (x) != IAC && (x) != CR )
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);
108 static void telnet_size(void);
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 */
116 REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE
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,
125 static struct Opt o_nenv = {WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON,
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};
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
140 static int sb_opt, sb_len;
141 static char *sb_buf = NULL;
142 static int sb_size = 0;
143 #define SB_DELTA 1024
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;
151 ret = send (s, outbuf+outbuf_reap, len, 0);
153 outbuf_reap = (outbuf_reap + ret) & OUTBUF_MASK;
159 static void s_write (void *buf, int len) {
160 unsigned char *p = buf;
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;
171 static void c_write (char *buf, int 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;
179 if( inbuf_head == inbuf_reap ) len++; else break;
184 static void log_option (char *sender, int cmd, int option) {
186 sprintf(buf, "%s:\t%s %s", sender,
187 (cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
188 cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<??>"),
193 static void send_opt (int cmd, int option) {
196 b[0] = IAC; b[1] = cmd; b[2] = option;
198 log_option("client", cmd, option);
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;
207 static void activate_option (struct Opt *o) {
208 if (o->send == WILL && o->option == TELOPT_NAWS)
210 if (o->send == WILL &&
211 (o->option == TELOPT_NEW_ENVIRON ||
212 o->option == TELOPT_OLD_ENVIRON)) {
214 * We may only have one kind of ENVIRON going at a time.
215 * This is a hack, but who cares.
217 deactivate_option (o->option==TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
221 static void refused_option (struct Opt *o) {
222 if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
223 o_oenv.state == INACTIVE) {
224 send_opt (WILL, TELOPT_OLD_ENVIRON);
225 o_oenv.state = REQUESTED;
229 static void proc_rec_opt (int cmd, int option) {
232 log_option ("server", cmd, option);
233 for (o = opts; *o; o++) {
234 if ((*o)->option == option && (*o)->ack == cmd) {
235 switch ((*o)->state) {
237 (*o)->state = ACTIVE;
238 activate_option (*o);
243 (*o)->state = ACTIVE;
244 send_opt ((*o)->send, option);
245 activate_option (*o);
247 case REALLY_INACTIVE:
248 send_opt ((*o)->nsend, option);
252 } else if ((*o)->option == option && (*o)->nak == cmd) {
253 switch ((*o)->state) {
255 (*o)->state = INACTIVE;
259 (*o)->state = INACTIVE;
260 send_opt ((*o)->nsend, option);
263 case REALLY_INACTIVE:
270 * If we reach here, the option was one we weren't prepared to
271 * cope with. So send a negative ack.
273 send_opt ((cmd == WILL ? DONT : WONT), option);
276 static void process_subneg (void) {
277 unsigned char b[2048], *p, *q;
283 if (sb_len == 1 && sb_buf[0] == TELQUAL_SEND) {
284 char logbuf[sizeof(cfg.termspeed)+80];
285 b[0] = IAC; b[1] = SB; b[2] = TELOPT_TSPEED;
287 strcpy(b+4, cfg.termspeed);
288 n = 4 + strlen(cfg.termspeed);
289 b[n] = IAC; b[n+1] = SE;
291 logevent("server:\tSB TSPEED SEND");
292 sprintf(logbuf, "client:\tSB TSPEED IS %s", cfg.termspeed);
295 logevent ("server:\tSB TSPEED <something weird>");
298 if (sb_len == 1 && sb_buf[0] == TELQUAL_SEND) {
299 char logbuf[sizeof(cfg.termtype)+80];
300 b[0] = IAC; b[1] = SB; b[2] = TELOPT_TTYPE;
302 for (n = 0; cfg.termtype[n]; n++)
303 b[n+4] = (cfg.termtype[n] >= 'a' && cfg.termtype[n] <= 'z' ?
304 cfg.termtype[n] + 'A'-'a' : cfg.termtype[n]);
305 b[n+4] = IAC; b[n+5] = SE;
308 logevent("server:\tSB TTYPE SEND");
309 sprintf(logbuf, "client:\tSB TTYPE IS %s", b+4);
312 logevent("server:\tSB TTYPE <something weird>\r\n");
314 case TELOPT_OLD_ENVIRON:
315 case TELOPT_NEW_ENVIRON:
318 if (p < q && *p == TELQUAL_SEND) {
321 sprintf (logbuf, "server:\tSB %s SEND", telopt(sb_opt));
323 if (sb_opt == TELOPT_OLD_ENVIRON) {
324 if (cfg.rfc_environ) {
332 * Try to guess the sense of VAR and VALUE.
338 } else if (*p == BSD_VAR) {
346 * With NEW_ENVIRON, the sense of VAR and VALUE
352 b[0] = IAC; b[1] = SB; b[2] = sb_opt;
358 while (*e && *e != '\t') b[n++] = *e++;
361 while (*e) b[n++] = *e++;
365 b[n++] = var; b[n++] = 'U'; b[n++] = 'S';
366 b[n++] = 'E'; b[n++] = 'R'; b[n++] = value;
368 while (*e) b[n++] = *e++;
370 b[n++] = IAC; b[n++] = SE;
372 sprintf(logbuf, "client:\tSB %s IS %s", telopt(sb_opt),
373 n==6 ? "<nothing>" : "<stuff>");
381 TOPLEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
382 SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
383 } telnet_state = TOPLEVEL;
385 static void do_telnet_read (char *buf, int len) {
389 int c = (unsigned char) *buf++;
391 switch (telnet_state) {
394 if (c == NUL && telnet_state == SEENCR)
395 telnet_state = TOPLEVEL;
397 telnet_state = SEENIAC;
405 telnet_state = SEENCR;
407 telnet_state = TOPLEVEL;
411 if (c == DO) telnet_state = SEENDO;
412 else if (c == DONT) telnet_state = SEENDONT;
413 else if (c == WILL) telnet_state = SEENWILL;
414 else if (c == WONT) telnet_state = SEENWONT;
415 else if (c == SB) telnet_state = SEENSB;
417 /* ignore everything else; print it if it's IAC */
422 telnet_state = TOPLEVEL;
426 proc_rec_opt (WILL, c);
427 telnet_state = TOPLEVEL;
430 proc_rec_opt (WONT, c);
431 telnet_state = TOPLEVEL;
434 proc_rec_opt (DO, c);
435 telnet_state = TOPLEVEL;
438 proc_rec_opt (DONT, c);
439 telnet_state = TOPLEVEL;
444 telnet_state = SUBNEGOT;
448 telnet_state = SUBNEG_IAC;
451 if (sb_len >= sb_size) {
455 realloc(sb_buf, sb_size) :
462 if (sb_len < sb_size)
463 sb_buf[sb_len++] = c;
464 telnet_state = SUBNEGOT;/* in case we came here by goto */
469 goto subneg_addchar; /* yes, it's a hack, I know, but... */
472 telnet_state = TOPLEVEL;
480 * Called to set up the Telnet connection. Will arrange for
481 * WM_NETEVENT messages to be passed to the specified window, whose
482 * window procedure should then call telnet_msg().
484 * Returns an error message, or NULL on success.
486 * Also places the canonical host name into `realhost'.
488 static char *telnet_init (HWND hwnd, char *host, int port, char **realhost) {
496 if ( (a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
497 if ( (h = gethostbyname(host)) == NULL)
498 switch (WSAGetLastError()) {
499 case WSAENETDOWN: return "Network is down";
500 case WSAHOST_NOT_FOUND: case WSANO_DATA:
501 return "Host does not exist";
502 case WSATRY_AGAIN: return "Host not found";
503 default: return "gethostbyname: unknown error";
505 memcpy (&a, h->h_addr, sizeof(a));
506 *realhost = h->h_name;
512 port = 23; /* default telnet port */
517 s = socket(AF_INET, SOCK_STREAM, 0);
518 if (s == INVALID_SOCKET)
519 switch (WSAGetLastError()) {
520 case WSAENETDOWN: return "Network is down";
521 case WSAEAFNOSUPPORT: return "TCP/IP support not present";
522 default: return "socket(): unknown error";
528 setsockopt (s, SOL_SOCKET, SO_OOBINLINE, (void *)&b, sizeof(b));
533 * Bind to local address.
535 addr.sin_family = AF_INET;
536 addr.sin_addr.s_addr = htonl(INADDR_ANY);
537 addr.sin_port = htons(0);
538 if (bind (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
539 switch (WSAGetLastError()) {
540 case WSAENETDOWN: return "Network is down";
541 default: return "bind(): unknown error";
545 * Connect to remote address.
547 addr.sin_addr.s_addr = htonl(a);
548 addr.sin_port = htons((short)port);
549 if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
550 switch (WSAGetLastError()) {
551 case WSAENETDOWN: return "Network is down";
552 case WSAECONNREFUSED: return "Connection refused";
553 case WSAENETUNREACH: return "Network is unreachable";
554 case WSAEHOSTUNREACH: return "No route to host";
555 default: return "connect(): unknown error";
558 if (WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ |
559 FD_WRITE | FD_OOB | FD_CLOSE) == SOCKET_ERROR)
560 switch (WSAGetLastError()) {
561 case WSAENETDOWN: return "Network is down";
562 default: return "WSAAsyncSelect(): unknown error";
566 * Initialise option states.
571 for (o = opts; *o; o++)
572 if ((*o)->state == REQUESTED)
573 send_opt ((*o)->send, (*o)->option);
578 * Set up SYNCH state.
587 * Process a WM_NETEVENT message. Will return 0 if the connection
588 * has closed, or <0 for a socket error.
590 static int telnet_msg (WPARAM wParam, LPARAM lParam) {
595 * Because reading less than the whole of the available pending
596 * data can generate an FD_READ event, we need to allow for the
597 * possibility that FD_READ may arrive with FD_CLOSE already in
598 * the queue; so it's possible that we can get here even with s
599 * invalid. If so, we return 1 and don't worry about it.
601 if (s == INVALID_SOCKET)
604 if (WSAGETSELECTERROR(lParam) != 0)
605 return -WSAGETSELECTERROR(lParam);
607 switch (WSAGETSELECTEVENT(lParam)) {
610 ret = recv(s, buf, sizeof(buf), 0);
611 if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK)
613 if (ret < 0) /* any _other_ error */
614 return -10000-WSAGetLastError();
622 if (ioctlsocket (s, SIOCATMARK, &i) < 0) {
623 return -20000-WSAGetLastError();
629 do_telnet_read (buf, ret);
633 ret = recv(s, buf, sizeof(buf), 0);
635 telnet_state = TOPLEVEL;
637 ret = recv(s, buf, 1, MSG_OOB);
639 do_telnet_read (buf, ret);
641 if (ret < 0 && WSAGetLastError() != WSAEWOULDBLOCK)
642 return -30000-WSAGetLastError();
645 if (outbuf_head != outbuf_reap)
649 return 1; /* shouldn't happen, but WTF */
653 * Called to send data down the Telnet connection.
655 static void telnet_send (char *buf, int len) {
657 static unsigned char iac[2] = { IAC, IAC };
658 static unsigned char cr[2] = { CR, NUL };
660 if (s == INVALID_SOCKET)
664 while (p < buf+len) {
667 while (iswritable((unsigned char)*p) && p < buf+len) p++;
670 while (p < buf+len && !iswritable((unsigned char)*p)) {
671 s_write ((unsigned char)*p == IAC ? iac : cr, 2);
678 * Called to set the size of the window from Telnet's POV.
680 static void telnet_size(void) {
684 if (s == INVALID_SOCKET || o_naws.state != ACTIVE)
686 b[0] = IAC; b[1] = SB; b[2] = TELOPT_NAWS;
687 b[3] = cols >> 8; b[4] = cols & 0xFF;
688 b[5] = rows >> 8; b[6] = rows & 0xFF;
689 b[7] = IAC; b[8] = SE;
691 sprintf(logbuf, "client:\tSB NAWS %d,%d",
692 ((unsigned char)b[3] << 8) + (unsigned char)b[4],
693 ((unsigned char)b[5] << 8) + (unsigned char)b[6]);
698 * Send Telnet special codes.
700 static void telnet_special (Telnet_Special code) {
703 if (s == INVALID_SOCKET)
708 case TS_AYT: b[1] = AYT; s_write (b, 2); break;
709 case TS_BRK: b[1] = BREAK; s_write (b, 2); break;
710 case TS_EC: b[1] = EC; s_write (b, 2); break;
711 case TS_EL: b[1] = EL; s_write (b, 2); break;
712 case TS_GA: b[1] = GA; s_write (b, 2); break;
713 case TS_NOP: b[1] = NOP; s_write (b, 2); break;
714 case TS_ABORT: b[1] = ABORT; s_write (b, 2); break;
715 case TS_AO: b[1] = AO; s_write (b, 2); break;
716 case TS_IP: b[1] = IP; s_write (b, 2); break;
717 case TS_SUSP: b[1] = SUSP; s_write (b, 2); break;
718 case TS_EOR: b[1] = EOR; s_write (b, 2); break;
719 case TS_EOF: b[1] = xEOF; s_write (b, 2); break;
721 outbuf_head = outbuf_reap = 0;
723 send (s, b, 1, MSG_OOB);
728 Backend telnet_backend = {