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putty/telnet.c

650 строки
18 KiB
C
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#include <windows.h>
#include <stdio.h>
#include <stdlib.h>
#include "putty.h"
#ifndef FALSE
#define FALSE 0
#endif
#ifndef TRUE
#define TRUE 1
#endif
static Socket s = NULL;
#define IAC 255 /* interpret as command: */
#define DONT 254 /* you are not to use option */
#define DO 253 /* please, you use option */
#define WONT 252 /* I won't use option */
#define WILL 251 /* I will use option */
#define SB 250 /* interpret as subnegotiation */
#define SE 240 /* end sub negotiation */
#define GA 249 /* you may reverse the line */
#define EL 248 /* erase the current line */
#define EC 247 /* erase the current character */
#define AYT 246 /* are you there */
#define AO 245 /* abort output--but let prog finish */
#define IP 244 /* interrupt process--permanently */
#define BREAK 243 /* break */
#define DM 242 /* data mark--for connect. cleaning */
#define NOP 241 /* nop */
#define EOR 239 /* end of record (transparent mode) */
#define ABORT 238 /* Abort process */
#define SUSP 237 /* Suspend process */
#define xEOF 236 /* End of file: EOF is already used... */
#define TELOPT_BINARY 0 /* 8-bit data path */
#define TELOPT_ECHO 1 /* echo */
#define TELOPT_RCP 2 /* prepare to reconnect */
#define TELOPT_SGA 3 /* suppress go ahead */
#define TELOPT_NAMS 4 /* approximate message size */
#define TELOPT_STATUS 5 /* give status */
#define TELOPT_TM 6 /* timing mark */
#define TELOPT_RCTE 7 /* remote controlled transmission and echo */
#define TELOPT_NAOL 8 /* negotiate about output line width */
#define TELOPT_NAOP 9 /* negotiate about output page size */
#define TELOPT_NAOCRD 10 /* negotiate about CR disposition */
#define TELOPT_NAOHTS 11 /* negotiate about horizontal tabstops */
#define TELOPT_NAOHTD 12 /* negotiate about horizontal tab disposition */
#define TELOPT_NAOFFD 13 /* negotiate about formfeed disposition */
#define TELOPT_NAOVTS 14 /* negotiate about vertical tab stops */
#define TELOPT_NAOVTD 15 /* negotiate about vertical tab disposition */
#define TELOPT_NAOLFD 16 /* negotiate about output LF disposition */
#define TELOPT_XASCII 17 /* extended ascic character set */
#define TELOPT_LOGOUT 18 /* force logout */
#define TELOPT_BM 19 /* byte macro */
#define TELOPT_DET 20 /* data entry terminal */
#define TELOPT_SUPDUP 21 /* supdup protocol */
#define TELOPT_SUPDUPOUTPUT 22 /* supdup output */
#define TELOPT_SNDLOC 23 /* send location */
#define TELOPT_TTYPE 24 /* terminal type */
#define TELOPT_EOR 25 /* end or record */
#define TELOPT_TUID 26 /* TACACS user identification */
#define TELOPT_OUTMRK 27 /* output marking */
#define TELOPT_TTYLOC 28 /* terminal location number */
#define TELOPT_3270REGIME 29 /* 3270 regime */
#define TELOPT_X3PAD 30 /* X.3 PAD */
#define TELOPT_NAWS 31 /* window size */
#define TELOPT_TSPEED 32 /* terminal speed */
#define TELOPT_LFLOW 33 /* remote flow control */
#define TELOPT_LINEMODE 34 /* Linemode option */
#define TELOPT_XDISPLOC 35 /* X Display Location */
#define TELOPT_OLD_ENVIRON 36 /* Old - Environment variables */
#define TELOPT_AUTHENTICATION 37/* Authenticate */
#define TELOPT_ENCRYPT 38 /* Encryption option */
#define TELOPT_NEW_ENVIRON 39 /* New - Environment variables */
#define TELOPT_EXOPL 255 /* extended-options-list */
#define TELQUAL_IS 0 /* option is... */
#define TELQUAL_SEND 1 /* send option */
#define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
#define BSD_VAR 1
#define BSD_VALUE 0
#define RFC_VAR 0
#define RFC_VALUE 1
#define CR 13
#define LF 10
#define NUL 0
#define iswritable(x) ( (x) != IAC && (x) != CR )
static char *telopt(int opt) {
#define i(x) if (opt == TELOPT_ ## x) return #x;
i(BINARY); i(ECHO); i(RCP); i(SGA); i(NAMS); i(STATUS); i(TM); i(RCTE);
i(NAOL); i(NAOP); i(NAOCRD); i(NAOHTS); i(NAOHTD); i(NAOFFD); i(NAOVTS);
i(NAOVTD); i(NAOLFD); i(XASCII); i(LOGOUT); i(BM); i(DET); i(SUPDUP);
i(SUPDUPOUTPUT); i(SNDLOC); i(TTYPE); i(EOR); i(TUID); i(OUTMRK);
i(TTYLOC); i(X3PAD); i(NAWS); i(TSPEED); i(LFLOW); i(LINEMODE);
i(XDISPLOC); i(OLD_ENVIRON); i(AUTHENTICATION); i(ENCRYPT);
i(NEW_ENVIRON); i(EXOPL);
#undef i
return "<unknown>";
}
static void telnet_size(void);
struct Opt {
int send; /* what we initially send */
int nsend; /* -ve send if requested to stop it */
int ack, nak; /* +ve and -ve acknowledgements */
int option; /* the option code */
enum {
REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE
} state;
};
static struct Opt o_naws = {WILL, WONT, DO, DONT, TELOPT_NAWS, REQUESTED};
static struct Opt o_tspeed = {WILL, WONT, DO, DONT, TELOPT_TSPEED, REQUESTED};
static struct Opt o_ttype = {WILL, WONT, DO, DONT, TELOPT_TTYPE, REQUESTED};
static struct Opt o_oenv = {WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON,
INACTIVE};
static struct Opt o_nenv = {WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON,
REQUESTED};
static struct Opt o_echo = {DO, DONT, WILL, WONT, TELOPT_ECHO, REQUESTED};
static struct Opt o_we_sga = {WILL, WONT, DO, DONT, TELOPT_SGA, REQUESTED};
static struct Opt o_they_sga = {DO, DONT, WILL, WONT, TELOPT_SGA, REQUESTED};
static struct Opt *opts[] = {
&o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,
&o_we_sga, &o_they_sga, NULL
};
static int echoing = TRUE, editing = TRUE;
static int in_synch;
static int sb_opt, sb_len;
static char *sb_buf = NULL;
static int sb_size = 0;
#define SB_DELTA 1024
static void c_write1(int c) {
char cc = (char)c;
from_backend(0, &cc, 1);
}
static void log_option (char *sender, int cmd, int option) {
char buf[50];
sprintf(buf, "%s:\t%s %s", sender,
(cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<??>"),
telopt(option));
logevent(buf);
}
static void send_opt (int cmd, int option) {
unsigned char b[3];
b[0] = IAC; b[1] = cmd; b[2] = option;
sk_write(s, b, 3);
log_option("client", cmd, option);
}
static void deactivate_option (struct Opt *o) {
if (o->state == REQUESTED || o->state == ACTIVE)
send_opt (o->nsend, o->option);
o->state = REALLY_INACTIVE;
}
/*
* Generate side effects of enabling or disabling an option.
*/
static void option_side_effects(struct Opt *o, int enabled) {
if (o->option == TELOPT_ECHO && o->send == DO)
echoing = !enabled;
else if (o->option = TELOPT_SGA && o->send == DO)
editing = !enabled;
ldisc_send(NULL, 0); /* cause ldisc to notice the change */
}
static void activate_option (struct Opt *o) {
if (o->send == WILL && o->option == TELOPT_NAWS)
telnet_size();
if (o->send == WILL &&
(o->option == TELOPT_NEW_ENVIRON ||
o->option == TELOPT_OLD_ENVIRON)) {
/*
* We may only have one kind of ENVIRON going at a time.
* This is a hack, but who cares.
*/
deactivate_option (o->option==TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
}
option_side_effects(o, 1);
}
static void refused_option (struct Opt *o) {
if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
o_oenv.state == INACTIVE) {
send_opt (WILL, TELOPT_OLD_ENVIRON);
o_oenv.state = REQUESTED;
}
option_side_effects(o, 0);
}
static void proc_rec_opt (int cmd, int option) {
struct Opt **o;
log_option ("server", cmd, option);
for (o = opts; *o; o++) {
if ((*o)->option == option && (*o)->ack == cmd) {
switch ((*o)->state) {
case REQUESTED:
(*o)->state = ACTIVE;
activate_option (*o);
break;
case ACTIVE:
break;
case INACTIVE:
(*o)->state = ACTIVE;
send_opt ((*o)->send, option);
activate_option (*o);
break;
case REALLY_INACTIVE:
send_opt ((*o)->nsend, option);
break;
}
return;
} else if ((*o)->option == option && (*o)->nak == cmd) {
switch ((*o)->state) {
case REQUESTED:
(*o)->state = INACTIVE;
refused_option (*o);
break;
case ACTIVE:
(*o)->state = INACTIVE;
send_opt ((*o)->nsend, option);
option_side_effects(*o, 0);
break;
case INACTIVE:
case REALLY_INACTIVE:
break;
}
return;
}
}
/*
* If we reach here, the option was one we weren't prepared to
* cope with. So send a negative ack.
*/
send_opt ((cmd == WILL ? DONT : WONT), option);
}
static void process_subneg (void) {
unsigned char b[2048], *p, *q;
int var, value, n;
char *e;
switch (sb_opt) {
case TELOPT_TSPEED:
if (sb_len == 1 && sb_buf[0] == TELQUAL_SEND) {
char logbuf[sizeof(cfg.termspeed)+80];
b[0] = IAC; b[1] = SB; b[2] = TELOPT_TSPEED;
b[3] = TELQUAL_IS;
strcpy(b+4, cfg.termspeed);
n = 4 + strlen(cfg.termspeed);
b[n] = IAC; b[n+1] = SE;
sk_write(s, b, n+2);
logevent("server:\tSB TSPEED SEND");
sprintf(logbuf, "client:\tSB TSPEED IS %s", cfg.termspeed);
logevent (logbuf);
} else
logevent ("server:\tSB TSPEED <something weird>");
break;
case TELOPT_TTYPE:
if (sb_len == 1 && sb_buf[0] == TELQUAL_SEND) {
char logbuf[sizeof(cfg.termtype)+80];
b[0] = IAC; b[1] = SB; b[2] = TELOPT_TTYPE;
b[3] = TELQUAL_IS;
for (n = 0; cfg.termtype[n]; n++)
b[n+4] = (cfg.termtype[n] >= 'a' && cfg.termtype[n] <= 'z' ?
cfg.termtype[n] + 'A'-'a' : cfg.termtype[n]);
b[n+4] = IAC; b[n+5] = SE;
sk_write(s, b, n+6);
b[n+4] = 0;
logevent("server:\tSB TTYPE SEND");
sprintf(logbuf, "client:\tSB TTYPE IS %s", b+4);
logevent(logbuf);
} else
logevent("server:\tSB TTYPE <something weird>\r\n");
break;
case TELOPT_OLD_ENVIRON:
case TELOPT_NEW_ENVIRON:
p = sb_buf;
q = p + sb_len;
if (p < q && *p == TELQUAL_SEND) {
char logbuf[50];
p++;
sprintf (logbuf, "server:\tSB %s SEND", telopt(sb_opt));
logevent (logbuf);
if (sb_opt == TELOPT_OLD_ENVIRON) {
if (cfg.rfc_environ) {
value = RFC_VALUE;
var = RFC_VAR;
} else {
value = BSD_VALUE;
var = BSD_VAR;
}
/*
* Try to guess the sense of VAR and VALUE.
*/
while (p < q) {
if (*p == RFC_VAR) {
value = RFC_VALUE;
var = RFC_VAR;
} else if (*p == BSD_VAR) {
value = BSD_VALUE;
var = BSD_VAR;
}
p++;
}
} else {
/*
* With NEW_ENVIRON, the sense of VAR and VALUE
* isn't in doubt.
*/
value = RFC_VALUE;
var = RFC_VAR;
}
b[0] = IAC; b[1] = SB; b[2] = sb_opt;
b[3] = TELQUAL_IS;
n = 4;
e = cfg.environmt;
while (*e) {
b[n++] = var;
while (*e && *e != '\t') b[n++] = *e++;
if (*e == '\t') e++;
b[n++] = value;
while (*e) b[n++] = *e++;
e++;
}
if (*cfg.username) {
b[n++] = var; b[n++] = 'U'; b[n++] = 'S';
b[n++] = 'E'; b[n++] = 'R'; b[n++] = value;
e = cfg.username;
while (*e) b[n++] = *e++;
}
b[n++] = IAC; b[n++] = SE;
sk_write(s, b, n);
sprintf(logbuf, "client:\tSB %s IS %s", telopt(sb_opt),
n==6 ? "<nothing>" : "<stuff>");
logevent (logbuf);
}
break;
}
}
static enum {
TOPLEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
} telnet_state = TOPLEVEL;
static void do_telnet_read (char *buf, int len) {
while (len--) {
int c = (unsigned char) *buf++;
switch (telnet_state) {
case TOPLEVEL:
case SEENCR:
if (c == NUL && telnet_state == SEENCR)
telnet_state = TOPLEVEL;
else if (c == IAC)
telnet_state = SEENIAC;
else {
if (!in_synch)
c_write1(c);
#if 1
/* I can't get the F***ing winsock to insert the urgent IAC
* into the right position! Even with SO_OOBINLINE it gives
* it to recv too soon. And of course the DM byte (that
* arrives in the same packet!) appears several K later!!
*
* Oh well, we do get the DM in the right place so I'll
* just stop hiding on the next 0xf2 and hope for the best.
*/
else if (c == DM) in_synch = 0;
#endif
if (c == CR)
telnet_state = SEENCR;
else
telnet_state = TOPLEVEL;
}
break;
case SEENIAC:
if (c == DO) telnet_state = SEENDO;
else if (c == DONT) telnet_state = SEENDONT;
else if (c == WILL) telnet_state = SEENWILL;
else if (c == WONT) telnet_state = SEENWONT;
else if (c == SB) telnet_state = SEENSB;
else if (c == DM) {
in_synch = 0;
telnet_state = TOPLEVEL;
}
else {
/* ignore everything else; print it if it's IAC */
if (c == IAC) {
c_write1(c);
}
telnet_state = TOPLEVEL;
}
break;
case SEENWILL:
proc_rec_opt (WILL, c);
telnet_state = TOPLEVEL;
break;
case SEENWONT:
proc_rec_opt (WONT, c);
telnet_state = TOPLEVEL;
break;
case SEENDO:
proc_rec_opt (DO, c);
telnet_state = TOPLEVEL;
break;
case SEENDONT:
proc_rec_opt (DONT, c);
telnet_state = TOPLEVEL;
break;
case SEENSB:
sb_opt = c;
sb_len = 0;
telnet_state = SUBNEGOT;
break;
case SUBNEGOT:
if (c == IAC)
telnet_state = SUBNEG_IAC;
else {
subneg_addchar:
if (sb_len >= sb_size) {
char *newbuf;
sb_size += SB_DELTA;
newbuf = (sb_buf ?
srealloc(sb_buf, sb_size) :
smalloc(sb_size));
if (newbuf)
sb_buf = newbuf;
else
sb_size -= SB_DELTA;
}
if (sb_len < sb_size)
sb_buf[sb_len++] = c;
telnet_state = SUBNEGOT;/* in case we came here by goto */
}
break;
case SUBNEG_IAC:
if (c != SE)
goto subneg_addchar; /* yes, it's a hack, I know, but... */
else {
process_subneg();
telnet_state = TOPLEVEL;
}
break;
}
}
}
static int telnet_receive(Socket skt, int urgent, char *data, int len) {
if (urgent==3) {
/* A socket error has occurred. */
sk_close(s);
s = NULL;
connection_fatal(data);
return 0;
} else if (!len) {
/* Connection has closed. */
sk_close(s);
s = NULL;
return 0;
}
if(urgent) in_synch = TRUE;
do_telnet_read (data, len);
return 1;
}
/*
* Called to set up the Telnet connection.
*
* Returns an error message, or NULL on success.
*
* Also places the canonical host name into `realhost'.
*/
static char *telnet_init (char *host, int port, char **realhost) {
SockAddr addr;
char *err;
/*
* Try to find host.
*/
addr = sk_namelookup(host, realhost);
if ( (err = sk_addr_error(addr)) )
return err;
if (port < 0)
port = 23; /* default telnet port */
/*
* Open socket.
*/
s = sk_new(addr, port, 0, 1, telnet_receive);
if ( (err = sk_socket_error(s)) )
return err;
sk_addr_free(addr);
/*
* Initialise option states.
*/
{
struct Opt **o;
for (o = opts; *o; o++)
if ((*o)->state == REQUESTED)
send_opt ((*o)->send, (*o)->option);
}
/*
* Set up SYNCH state.
*/
in_synch = FALSE;
return NULL;
}
/*
* Called to send data down the Telnet connection.
*/
static void telnet_send (char *buf, int len) {
char *p;
static unsigned char iac[2] = { IAC, IAC };
static unsigned char cr[2] = { CR, NUL };
static unsigned char nl[2] = { CR, LF };
if (s == NULL)
return;
p = buf;
while (p < buf+len) {
char *q = p;
while (iswritable((unsigned char)*p) && p < buf+len) p++;
sk_write(s, q, p-q);
while (p < buf+len && !iswritable((unsigned char)*p)) {
sk_write(s, (unsigned char)*p == IAC ? iac : nl, 2);
p++;
}
}
}
/*
* Called to set the size of the window from Telnet's POV.
*/
static void telnet_size(void) {
unsigned char b[16];
char logbuf[50];
if (s == NULL || o_naws.state != ACTIVE)
return;
b[0] = IAC; b[1] = SB; b[2] = TELOPT_NAWS;
b[3] = cols >> 8; b[4] = cols & 0xFF;
b[5] = rows >> 8; b[6] = rows & 0xFF;
b[7] = IAC; b[8] = SE;
sk_write(s, b, 9);
sprintf(logbuf, "client:\tSB NAWS %d,%d",
((unsigned char)b[3] << 8) + (unsigned char)b[4],
((unsigned char)b[5] << 8) + (unsigned char)b[6]);
logevent (logbuf);
}
/*
* Send Telnet special codes.
*/
static void telnet_special (Telnet_Special code) {
unsigned char b[2];
if (s == NULL)
return;
b[0] = IAC;
switch (code) {
case TS_AYT: b[1] = AYT; sk_write(s, b, 2); break;
case TS_BRK: b[1] = BREAK; sk_write(s, b, 2); break;
case TS_EC: b[1] = EC; sk_write(s, b, 2); break;
case TS_EL: b[1] = EL; sk_write(s, b, 2); break;
case TS_GA: b[1] = GA; sk_write(s, b, 2); break;
case TS_NOP: b[1] = NOP; sk_write(s, b, 2); break;
case TS_ABORT: b[1] = ABORT; sk_write(s, b, 2); break;
case TS_AO: b[1] = AO; sk_write(s, b, 2); break;
case TS_IP: b[1] = IP; sk_write(s, b, 2); break;
case TS_SUSP: b[1] = SUSP; sk_write(s, b, 2); break;
case TS_EOR: b[1] = EOR; sk_write(s, b, 2); break;
case TS_EOF: b[1] = xEOF; sk_write(s, b, 2); break;
case TS_SYNCH:
b[1] = DM;
sk_write (s, b, 1);
sk_write_oob (s, b+1, 1);
break;
case TS_RECHO:
if (o_echo.state == INACTIVE || o_echo.state == REALLY_INACTIVE) {
o_echo.state = REQUESTED;
send_opt (o_echo.send, o_echo.option);
}
break;
case TS_LECHO:
if (o_echo.state == ACTIVE) {
o_echo.state = REQUESTED;
send_opt (o_echo.nsend, o_echo.option);
}
break;
case TS_PING:
if (o_they_sga.state == ACTIVE) {
b[1] = NOP;
sk_write(s, b, 2);
}
break;
}
}
static Socket telnet_socket(void) { return s; }
static int telnet_sendok(void) { return 1; }
static int telnet_ldisc(int option) {
if (option == LD_ECHO) return echoing;
if (option == LD_EDIT) return editing;
return FALSE;
}
Backend telnet_backend = {
telnet_init,
telnet_send,
telnet_size,
telnet_special,
telnet_socket,
telnet_sendok,
telnet_ldisc,
23
};
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