[u/mdw/putty] / telnet.c

#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_closing(Plug plug, char *error_msg, int error_code,
			  int calling_back)
{
    sk_close(s);
    s = NULL;
    if (error_msg) {
	/* A socket error has occurred. */
	connection_fatal(error_msg);
    }				       /* Otherwise, the remote side closed the connection normally. */
    return 0;
}

static int telnet_receive(Plug plug, int urgent, char *data, int len)
{
    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)
{
    static struct plug_function_table fn_table = {
	telnet_closing,
	telnet_receive
    }, *fn_table_ptr = &fn_table;

    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, &fn_table_ptr);
    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
};
Commit	Line	Data
374330e2	1	#include <windows.h>
	2	#include <stdio.h>
	3	#include <stdlib.h>
374330e2	4
	5	#include "putty.h"
	6
	7	#ifndef FALSE
	8	#define FALSE 0
	9	#endif
	10	#ifndef TRUE
	11	#define TRUE 1
	12	#endif
	13
8df7a775	14	static Socket s = NULL;
374330e2	15
32874aea	16	#define IAC 255 /* interpret as command: */
	17	#define DONT 254 /* you are not to use option */
	18	#define DO 253 /* please, you use option */
	19	#define WONT 252 /* I won't use option */
	20	#define WILL 251 /* I will use option */
	21	#define SB 250 /* interpret as subnegotiation */
	22	#define SE 240 /* end sub negotiation */
	23
	24	#define GA 249 /* you may reverse the line */
	25	#define EL 248 /* erase the current line */
	26	#define EC 247 /* erase the current character */
	27	#define AYT 246 /* are you there */
	28	#define AO 245 /* abort output--but let prog finish */
	29	#define IP 244 /* interrupt process--permanently */
	30	#define BREAK 243 /* break */
	31	#define DM 242 /* data mark--for connect. cleaning */
	32	#define NOP 241 /* nop */
	33	#define EOR 239 /* end of record (transparent mode) */
	34	#define ABORT 238 /* Abort process */
	35	#define SUSP 237 /* Suspend process */
	36	#define xEOF 236 /* End of file: EOF is already used... */
	37
	38	#define TELOPT_BINARY 0 /* 8-bit data path */
	39	#define TELOPT_ECHO 1 /* echo */
	40	#define TELOPT_RCP 2 /* prepare to reconnect */
	41	#define TELOPT_SGA 3 /* suppress go ahead */
	42	#define TELOPT_NAMS 4 /* approximate message size */
	43	#define TELOPT_STATUS 5 /* give status */
	44	#define TELOPT_TM 6 /* timing mark */
	45	#define TELOPT_RCTE 7 /* remote controlled transmission and echo */
	46	#define TELOPT_NAOL 8 /* negotiate about output line width */
	47	#define TELOPT_NAOP 9 /* negotiate about output page size */
	48	#define TELOPT_NAOCRD 10 /* negotiate about CR disposition */
	49	#define TELOPT_NAOHTS 11 /* negotiate about horizontal tabstops */
	50	#define TELOPT_NAOHTD 12 /* negotiate about horizontal tab disposition */
	51	#define TELOPT_NAOFFD 13 /* negotiate about formfeed disposition */
	52	#define TELOPT_NAOVTS 14 /* negotiate about vertical tab stops */
	53	#define TELOPT_NAOVTD 15 /* negotiate about vertical tab disposition */
	54	#define TELOPT_NAOLFD 16 /* negotiate about output LF disposition */
	55	#define TELOPT_XASCII 17 /* extended ascic character set */
	56	#define TELOPT_LOGOUT 18 /* force logout */
	57	#define TELOPT_BM 19 /* byte macro */
	58	#define TELOPT_DET 20 /* data entry terminal */
	59	#define TELOPT_SUPDUP 21 /* supdup protocol */
	60	#define TELOPT_SUPDUPOUTPUT 22 /* supdup output */
	61	#define TELOPT_SNDLOC 23 /* send location */
	62	#define TELOPT_TTYPE 24 /* terminal type */
	63	#define TELOPT_EOR 25 /* end or record */
	64	#define TELOPT_TUID 26 /* TACACS user identification */
	65	#define TELOPT_OUTMRK 27 /* output marking */
	66	#define TELOPT_TTYLOC 28 /* terminal location number */
	67	#define TELOPT_3270REGIME 29 /* 3270 regime */
	68	#define TELOPT_X3PAD 30 /* X.3 PAD */
	69	#define TELOPT_NAWS 31 /* window size */
	70	#define TELOPT_TSPEED 32 /* terminal speed */
	71	#define TELOPT_LFLOW 33 /* remote flow control */
	72	#define TELOPT_LINEMODE 34 /* Linemode option */
	73	#define TELOPT_XDISPLOC 35 /* X Display Location */
	74	#define TELOPT_OLD_ENVIRON 36 /* Old - Environment variables */
	75	#define TELOPT_AUTHENTICATION 37 /* Authenticate */
	76	#define TELOPT_ENCRYPT 38 /* Encryption option */
	77	#define TELOPT_NEW_ENVIRON 39 /* New - Environment variables */
	78	#define TELOPT_EXOPL 255 /* extended-options-list */
	79
80	#define TELQUAL_IS 0 /* option is... */
81	#define TELQUAL_SEND 1 /* send option */
82	#define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
374330e2	83	#define BSD_VAR 1
	84	#define BSD_VALUE 0
	85	#define RFC_VAR 0
	86	#define RFC_VALUE 1
	87
	88	#define CR 13
	89	#define LF 10
	90	#define NUL 0
	91
	92	#define iswritable(x) ( (x) != IAC && (x) != CR )
	93
32874aea	94	static char *telopt(int opt)
32874aea	95	{
374330e2	96	#define i(x) if (opt == TELOPT_ ## x) return #x;
32874aea	97	i(BINARY);
	98	i(ECHO);
	99	i(RCP);
	100	i(SGA);
	101	i(NAMS);
	102	i(STATUS);
	103	i(TM);
	104	i(RCTE);
	105	i(NAOL);
	106	i(NAOP);
	107	i(NAOCRD);
	108	i(NAOHTS);
	109	i(NAOHTD);
	110	i(NAOFFD);
	111	i(NAOVTS);
	112	i(NAOVTD);
	113	i(NAOLFD);
	114	i(XASCII);
	115	i(LOGOUT);
	116	i(BM);
	117	i(DET);
	118	i(SUPDUP);
	119	i(SUPDUPOUTPUT);
	120	i(SNDLOC);
	121	i(TTYPE);
	122	i(EOR);
	123	i(TUID);
	124	i(OUTMRK);
	125	i(TTYLOC);
	126	i(X3PAD);
	127	i(NAWS);
	128	i(TSPEED);
	129	i(LFLOW);
	130	i(LINEMODE);
	131	i(XDISPLOC);
	132	i(OLD_ENVIRON);
	133	i(AUTHENTICATION);
	134	i(ENCRYPT);
	135	i(NEW_ENVIRON);
	136	i(EXOPL);
374330e2	137	#undef i
	138	return "<unknown>";
	139	}
	140
	141	static void telnet_size(void);
	142
	143	struct Opt {
	144	int send; /* what we initially send */
	145	int nsend; /* -ve send if requested to stop it */
	146	int ack, nak; /* +ve and -ve acknowledgements */
	147	int option; /* the option code */
	148	enum {
	149	REQUESTED, ACTIVE, INACTIVE, REALLY_INACTIVE
	150	} state;
	151	};
	152
32874aea	153	static struct Opt o_naws =
	154	{ WILL, WONT, DO, DONT, TELOPT_NAWS, REQUESTED };
	155	static struct Opt o_tspeed =
	156	{ WILL, WONT, DO, DONT, TELOPT_TSPEED, REQUESTED };
	157	static struct Opt o_ttype =
	158	{ WILL, WONT, DO, DONT, TELOPT_TTYPE, REQUESTED };
	159	static struct Opt o_oenv = { WILL, WONT, DO, DONT, TELOPT_OLD_ENVIRON,
	160	INACTIVE
	161	};
	162	static struct Opt o_nenv = { WILL, WONT, DO, DONT, TELOPT_NEW_ENVIRON,
	163	REQUESTED
	164	};
	165	static struct Opt o_echo =
	166	{ DO, DONT, WILL, WONT, TELOPT_ECHO, REQUESTED };
	167	static struct Opt o_we_sga =
	168	{ WILL, WONT, DO, DONT, TELOPT_SGA, REQUESTED };
	169	static struct Opt o_they_sga =
	170	{ DO, DONT, WILL, WONT, TELOPT_SGA, REQUESTED };
374330e2	171
	172	static struct Opt *opts[] = {
	173	&o_naws, &o_tspeed, &o_ttype, &o_oenv, &o_nenv, &o_echo,
	174	&o_we_sga, &o_they_sga, NULL
	175	};
	176
0965bee0	177	static int echoing = TRUE, editing = TRUE;
0965bee0	178
374330e2	179	static int in_synch;
374330e2	180	static int sb_opt, sb_len;
	181	static char *sb_buf = NULL;
	182	static int sb_size = 0;
	183	#define SB_DELTA 1024
	184
32874aea	185	static void c_write1(int c)
	186	{
	187	char cc = (char) c;
fe50e814	188	from_backend(0, &cc, 1);
	189	}
	190
32874aea	191	static void log_option(char *sender, int cmd, int option)
32874aea	192	{
374330e2	193	char buf[50];
	194	sprintf(buf, "%s:\t%s %s", sender,
	195	(cmd == WILL ? "WILL" : cmd == WONT ? "WONT" :
	196	cmd == DO ? "DO" : cmd == DONT ? "DONT" : "<??>"),
	197	telopt(option));
c5e9c988	198	logevent(buf);
374330e2	199	}
374330e2	200
32874aea	201	static void send_opt(int cmd, int option)
32874aea	202	{
374330e2	203	unsigned char b[3];
374330e2	204
32874aea	205	b[0] = IAC;
	206	b[1] = cmd;
	207	b[2] = option;
8df7a775	208	sk_write(s, b, 3);
374330e2	209	log_option("client", cmd, option);
	210	}
	211
32874aea	212	static void deactivate_option(struct Opt *o)
32874aea	213	{
374330e2	214	if (o->state == REQUESTED \|\| o->state == ACTIVE)
32874aea	215	send_opt(o->nsend, o->option);
374330e2	216	o->state = REALLY_INACTIVE;
	217	}
	218
708bbbbe	219	/*
	220	* Generate side effects of enabling or disabling an option.
	221	*/
32874aea	222	static void option_side_effects(struct Opt *o, int enabled)
32874aea	223	{
0965bee0	224	if (o->option == TELOPT_ECHO && o->send == DO)
32874aea	225	echoing = !enabled;
b6c680d4	226	else if (o->option == TELOPT_SGA && o->send == DO)
32874aea	227	editing = !enabled;
32874aea	228	ldisc_send(NULL, 0); /* cause ldisc to notice the change */
708bbbbe	229	}
708bbbbe	230
32874aea	231	static void activate_option(struct Opt *o)
32874aea	232	{
374330e2	233	if (o->send == WILL && o->option == TELOPT_NAWS)
	234	telnet_size();
	235	if (o->send == WILL &&
	236	(o->option == TELOPT_NEW_ENVIRON \|\|
	237	o->option == TELOPT_OLD_ENVIRON)) {
	238	/*
	239	* We may only have one kind of ENVIRON going at a time.
	240	* This is a hack, but who cares.
	241	*/
32874aea	242	deactivate_option(o->option ==
32874aea	243	TELOPT_NEW_ENVIRON ? &o_oenv : &o_nenv);
374330e2	244	}
708bbbbe	245	option_side_effects(o, 1);
374330e2	246	}
374330e2	247
32874aea	248	static void refused_option(struct Opt *o)
32874aea	249	{
374330e2	250	if (o->send == WILL && o->option == TELOPT_NEW_ENVIRON &&
374330e2	251	o_oenv.state == INACTIVE) {
32874aea	252	send_opt(WILL, TELOPT_OLD_ENVIRON);
374330e2	253	o_oenv.state = REQUESTED;
374330e2	254	}
708bbbbe	255	option_side_effects(o, 0);
374330e2	256	}
374330e2	257
32874aea	258	static void proc_rec_opt(int cmd, int option)
32874aea	259	{
374330e2	260	struct Opt **o;
374330e2	261
32874aea	262	log_option("server", cmd, option);
374330e2	263	for (o = opts; *o; o++) {
	264	if ((o)->option == option && (o)->ack == cmd) {
	265	switch ((*o)->state) {
	266	case REQUESTED:
	267	(*o)->state = ACTIVE;
32874aea	268	activate_option(*o);
374330e2	269	break;
	270	case ACTIVE:
	271	break;
	272	case INACTIVE:
	273	(*o)->state = ACTIVE;
32874aea	274	send_opt((*o)->send, option);
32874aea	275	activate_option(*o);
374330e2	276	break;
374330e2	277	case REALLY_INACTIVE:
32874aea	278	send_opt((*o)->nsend, option);
374330e2	279	break;
	280	}
	281	return;
	282	} else if ((o)->option == option && (o)->nak == cmd) {
	283	switch ((*o)->state) {
	284	case REQUESTED:
	285	(*o)->state = INACTIVE;
32874aea	286	refused_option(*o);
374330e2	287	break;
	288	case ACTIVE:
	289	(*o)->state = INACTIVE;
32874aea	290	send_opt((*o)->nsend, option);
32874aea	291	option_side_effects(*o, 0);
374330e2	292	break;
	293	case INACTIVE:
	294	case REALLY_INACTIVE:
	295	break;
	296	}
	297	return;
	298	}
	299	}
	300	/*
	301	* If we reach here, the option was one we weren't prepared to
	302	* cope with. So send a negative ack.
	303	*/
32874aea	304	send_opt((cmd == WILL ? DONT : WONT), option);
374330e2	305	}
374330e2	306
32874aea	307	static void process_subneg(void)
32874aea	308	{
374330e2	309	unsigned char b[2048], p, q;
	310	int var, value, n;
	311	char *e;
	312
	313	switch (sb_opt) {
	314	case TELOPT_TSPEED:
	315	if (sb_len == 1 && sb_buf[0] == TELQUAL_SEND) {
32874aea	316	char logbuf[sizeof(cfg.termspeed) + 80];
	317	b[0] = IAC;
	318	b[1] = SB;
	319	b[2] = TELOPT_TSPEED;
374330e2	320	b[3] = TELQUAL_IS;
32874aea	321	strcpy(b + 4, cfg.termspeed);
374330e2	322	n = 4 + strlen(cfg.termspeed);
32874aea	323	b[n] = IAC;
	324	b[n + 1] = SE;
	325	sk_write(s, b, n + 2);
c5e9c988	326	logevent("server:\tSB TSPEED SEND");
374330e2	327	sprintf(logbuf, "client:\tSB TSPEED IS %s", cfg.termspeed);
32874aea	328	logevent(logbuf);
374330e2	329	} else
32874aea	330	logevent("server:\tSB TSPEED <something weird>");
374330e2	331	break;
	332	case TELOPT_TTYPE:
	333	if (sb_len == 1 && sb_buf[0] == TELQUAL_SEND) {
32874aea	334	char logbuf[sizeof(cfg.termtype) + 80];
	335	b[0] = IAC;
	336	b[1] = SB;
	337	b[2] = TELOPT_TTYPE;
374330e2	338	b[3] = TELQUAL_IS;
374330e2	339	for (n = 0; cfg.termtype[n]; n++)
32874aea	340	b[n + 4] = (cfg.termtype[n] >= 'a'
	341	&& cfg.termtype[n] <=
	342	'z' ? cfg.termtype[n] + 'A' -
	343	'a' : cfg.termtype[n]);
	344	b[n + 4] = IAC;
	345	b[n + 5] = SE;
	346	sk_write(s, b, n + 6);
	347	b[n + 4] = 0;
c5e9c988	348	logevent("server:\tSB TTYPE SEND");
32874aea	349	sprintf(logbuf, "client:\tSB TTYPE IS %s", b + 4);
c5e9c988	350	logevent(logbuf);
374330e2	351	} else
c5e9c988	352	logevent("server:\tSB TTYPE <something weird>\r\n");
374330e2	353	break;
374330e2	354	case TELOPT_OLD_ENVIRON:
32874aea	355	case TELOPT_NEW_ENVIRON:
374330e2	356	p = sb_buf;
	357	q = p + sb_len;
	358	if (p < q && *p == TELQUAL_SEND) {
	359	char logbuf[50];
	360	p++;
32874aea	361	sprintf(logbuf, "server:\tSB %s SEND", telopt(sb_opt));
32874aea	362	logevent(logbuf);
374330e2	363	if (sb_opt == TELOPT_OLD_ENVIRON) {
	364	if (cfg.rfc_environ) {
	365	value = RFC_VALUE;
	366	var = RFC_VAR;
	367	} else {
	368	value = BSD_VALUE;
	369	var = BSD_VAR;
	370	}
	371	/*
	372	* Try to guess the sense of VAR and VALUE.
	373	*/
	374	while (p < q) {
	375	if (*p == RFC_VAR) {
	376	value = RFC_VALUE;
	377	var = RFC_VAR;
	378	} else if (*p == BSD_VAR) {
	379	value = BSD_VALUE;
	380	var = BSD_VAR;
	381	}
	382	p++;
	383	}
	384	} else {
	385	/*
	386	* With NEW_ENVIRON, the sense of VAR and VALUE
	387	* isn't in doubt.
	388	*/
	389	value = RFC_VALUE;
	390	var = RFC_VAR;
	391	}
32874aea	392	b[0] = IAC;
	393	b[1] = SB;
	394	b[2] = sb_opt;
374330e2	395	b[3] = TELQUAL_IS;
374330e2	396	n = 4;
32874aea	397	e = cfg.environmt;
374330e2	398	while (*e) {
374330e2	399	b[n++] = var;
32874aea	400	while (e && e != '\t')
	401	b[n++] = *e++;
	402	if (*e == '\t')
	403	e++;
374330e2	404	b[n++] = value;
32874aea	405	while (*e)
32874aea	406	b[n++] = *e++;
374330e2	407	e++;
	408	}
	409	if (*cfg.username) {
32874aea	410	b[n++] = var;
	411	b[n++] = 'U';
	412	b[n++] = 'S';
	413	b[n++] = 'E';
	414	b[n++] = 'R';
	415	b[n++] = value;
374330e2	416	e = cfg.username;
32874aea	417	while (*e)
32874aea	418	b[n++] = *e++;
374330e2	419	}
32874aea	420	b[n++] = IAC;
32874aea	421	b[n++] = SE;
8df7a775	422	sk_write(s, b, n);
374330e2	423	sprintf(logbuf, "client:\tSB %s IS %s", telopt(sb_opt),
32874aea	424	n == 6 ? "<nothing>" : "<stuff>");
32874aea	425	logevent(logbuf);
374330e2	426	}
	427	break;
	428	}
	429	}
	430
	431	static enum {
	432	TOPLEVEL, SEENIAC, SEENWILL, SEENWONT, SEENDO, SEENDONT,
	433	SEENSB, SUBNEGOT, SUBNEG_IAC, SEENCR
	434	} telnet_state = TOPLEVEL;
	435
32874aea	436	static void do_telnet_read(char *buf, int len)
32874aea	437	{
374330e2	438
	439	while (len--) {
	440	int c = (unsigned char) *buf++;
	441
	442	switch (telnet_state) {
	443	case TOPLEVEL:
	444	case SEENCR:
	445	if (c == NUL && telnet_state == SEENCR)
	446	telnet_state = TOPLEVEL;
	447	else if (c == IAC)
	448	telnet_state = SEENIAC;
	449	else {
374330e2	450	if (!in_synch)
c9def1b8	451	c_write1(c);
2f938b83	452
	453	#if 1
	454	/* I can't get the F***ing winsock to insert the urgent IAC
	455	* into the right position! Even with SO_OOBINLINE it gives
	456	* it to recv too soon. And of course the DM byte (that
	457	* arrives in the same packet!) appears several K later!!
	458	*
	459	* Oh well, we do get the DM in the right place so I'll
	460	* just stop hiding on the next 0xf2 and hope for the best.
	461	*/
32874aea	462	else if (c == DM)
32874aea	463	in_synch = 0;
2f938b83	464	#endif
374330e2	465	if (c == CR)
	466	telnet_state = SEENCR;
	467	else
	468	telnet_state = TOPLEVEL;
	469	}
	470	break;
	471	case SEENIAC:
32874aea	472	if (c == DO)
	473	telnet_state = SEENDO;
	474	else if (c == DONT)
	475	telnet_state = SEENDONT;
	476	else if (c == WILL)
	477	telnet_state = SEENWILL;
	478	else if (c == WONT)
	479	telnet_state = SEENWONT;
	480	else if (c == SB)
	481	telnet_state = SEENSB;
2f938b83	482	else if (c == DM) {
32874aea	483	in_synch = 0;
2f938b83	484	telnet_state = TOPLEVEL;
32874aea	485	} else {
ded38628	486	/* ignore everything else; print it if it's IAC */
ded38628	487	if (c == IAC) {
c9def1b8	488	c_write1(c);
ded38628	489	}
300d41b0	490	telnet_state = TOPLEVEL;
300d41b0	491	}
374330e2	492	break;
374330e2	493	case SEENWILL:
32874aea	494	proc_rec_opt(WILL, c);
374330e2	495	telnet_state = TOPLEVEL;
	496	break;
	497	case SEENWONT:
32874aea	498	proc_rec_opt(WONT, c);
374330e2	499	telnet_state = TOPLEVEL;
	500	break;
	501	case SEENDO:
32874aea	502	proc_rec_opt(DO, c);
374330e2	503	telnet_state = TOPLEVEL;
	504	break;
	505	case SEENDONT:
32874aea	506	proc_rec_opt(DONT, c);
374330e2	507	telnet_state = TOPLEVEL;
	508	break;
	509	case SEENSB:
	510	sb_opt = c;
	511	sb_len = 0;
	512	telnet_state = SUBNEGOT;
	513	break;
	514	case SUBNEGOT:
	515	if (c == IAC)
	516	telnet_state = SUBNEG_IAC;
	517	else {
32874aea	518	subneg_addchar:
374330e2	519	if (sb_len >= sb_size) {
	520	char *newbuf;
	521	sb_size += SB_DELTA;
	522	newbuf = (sb_buf ?
c9def1b8	523	srealloc(sb_buf, sb_size) :
c9def1b8	524	smalloc(sb_size));
374330e2	525	if (newbuf)
	526	sb_buf = newbuf;
	527	else
	528	sb_size -= SB_DELTA;
	529	}
	530	if (sb_len < sb_size)
	531	sb_buf[sb_len++] = c;
32874aea	532	telnet_state = SUBNEGOT; /* in case we came here by goto */
374330e2	533	}
	534	break;
	535	case SUBNEG_IAC:
	536	if (c != SE)
	537	goto subneg_addchar; /* yes, it's a hack, I know, but... */
	538	else {
	539	process_subneg();
	540	telnet_state = TOPLEVEL;
	541	}
	542	break;
	543	}
	544	}
	545	}
	546
32874aea	547	static int telnet_closing(Plug plug, char *error_msg, int error_code,
	548	int calling_back)
	549	{
7e78000d	550	sk_close(s);
	551	s = NULL;
	552	if (error_msg) {
32874aea	553	/* A socket error has occurred. */
	554	connection_fatal(error_msg);
	555	} /* Otherwise, the remote side closed the connection normally. */
7e78000d	556	return 0;
	557	}
	558
32874aea	559	static int telnet_receive(Plug plug, int urgent, char *data, int len)
	560	{
	561	if (urgent)
	562	in_synch = TRUE;
	563	do_telnet_read(data, len);
8df7a775	564	return 1;
	565	}
	566
374330e2	567	/*
8df7a775	568	* Called to set up the Telnet connection.
374330e2	569	*
	570	* Returns an error message, or NULL on success.
	571	*
	572	* Also places the canonical host name into `realhost'.
	573	*/
32874aea	574	static char telnet_init(char host, int port, char **realhost)
32874aea	575	{
7e78000d	576	static struct plug_function_table fn_table = {
	577	telnet_closing,
	578	telnet_receive
	579	}, *fn_table_ptr = &fn_table;
	580
8df7a775	581	SockAddr addr;
8df7a775	582	char *err;
374330e2	583
	584	/*
	585	* Try to find host.
	586	*/
8df7a775	587	addr = sk_namelookup(host, realhost);
32874aea	588	if ((err = sk_addr_error(addr)))
8df7a775	589	return err;
374330e2	590
	591	if (port < 0)
	592	port = 23; /* default telnet port */
	593
	594	/*
	595	* Open socket.
	596	*/
7e78000d	597	s = sk_new(addr, port, 0, 1, &fn_table_ptr);
32874aea	598	if ((err = sk_socket_error(s)))
8df7a775	599	return err;
374330e2	600
8df7a775	601	sk_addr_free(addr);
374330e2	602
	603	/*
	604	* Initialise option states.
	605	*/
	606	{
	607	struct Opt **o;
	608
	609	for (o = opts; *o; o++)
	610	if ((*o)->state == REQUESTED)
32874aea	611	send_opt((o)->send, (o)->option);
374330e2	612	}
374330e2	613
374330e2	614	/*
	615	* Set up SYNCH state.
	616	*/
	617	in_synch = FALSE;
6f34e365	618
374330e2	619	return NULL;
	620	}
	621
	622	/*
374330e2	623	* Called to send data down the Telnet connection.
374330e2	624	*/
32874aea	625	static void telnet_send(char *buf, int len)
32874aea	626	{
374330e2	627	char *p;
	628	static unsigned char iac[2] = { IAC, IAC };
	629	static unsigned char cr[2] = { CR, NUL };
eb5e1db9	630	static unsigned char nl[2] = { CR, LF };
374330e2	631
8df7a775	632	if (s == NULL)
374330e2	633	return;
	634
	635	p = buf;
32874aea	636	while (p < buf + len) {
374330e2	637	char *q = p;
374330e2	638
32874aea	639	while (iswritable((unsigned char) *p) && p < buf + len)
	640	p++;
	641	sk_write(s, q, p - q);
374330e2	642
32874aea	643	while (p < buf + len && !iswritable((unsigned char) *p)) {
32874aea	644	sk_write(s, (unsigned char) *p == IAC ? iac : nl, 2);
374330e2	645	p++;
	646	}
	647	}
	648	}
	649
	650	/*
	651	* Called to set the size of the window from Telnet's POV.
	652	*/
32874aea	653	static void telnet_size(void)
32874aea	654	{
374330e2	655	unsigned char b[16];
	656	char logbuf[50];
	657
8df7a775	658	if (s == NULL \|\| o_naws.state != ACTIVE)
374330e2	659	return;
32874aea	660	b[0] = IAC;
	661	b[1] = SB;
	662	b[2] = TELOPT_NAWS;
	663	b[3] = cols >> 8;
	664	b[4] = cols & 0xFF;
	665	b[5] = rows >> 8;
	666	b[6] = rows & 0xFF;
	667	b[7] = IAC;
	668	b[8] = SE;
8df7a775	669	sk_write(s, b, 9);
374330e2	670	sprintf(logbuf, "client:\tSB NAWS %d,%d",
32874aea	671	((unsigned char) b[3] << 8) + (unsigned char) b[4],
	672	((unsigned char) b[5] << 8) + (unsigned char) b[6]);
	673	logevent(logbuf);
374330e2	674	}
	675
	676	/*
	677	* Send Telnet special codes.
	678	*/
32874aea	679	static void telnet_special(Telnet_Special code)
32874aea	680	{
374330e2	681	unsigned char b[2];
374330e2	682
8df7a775	683	if (s == NULL)
374330e2	684	return;
	685
	686	b[0] = IAC;
	687	switch (code) {
32874aea	688	case TS_AYT:
	689	b[1] = AYT;
	690	sk_write(s, b, 2);
	691	break;
	692	case TS_BRK:
	693	b[1] = BREAK;
	694	sk_write(s, b, 2);
	695	break;
	696	case TS_EC:
	697	b[1] = EC;
	698	sk_write(s, b, 2);
	699	break;
	700	case TS_EL:
	701	b[1] = EL;
	702	sk_write(s, b, 2);
	703	break;
	704	case TS_GA:
	705	b[1] = GA;
	706	sk_write(s, b, 2);
	707	break;
	708	case TS_NOP:
	709	b[1] = NOP;
	710	sk_write(s, b, 2);
	711	break;
	712	case TS_ABORT:
	713	b[1] = ABORT;
	714	sk_write(s, b, 2);
	715	break;
	716	case TS_AO:
	717	b[1] = AO;
	718	sk_write(s, b, 2);
	719	break;
	720	case TS_IP:
	721	b[1] = IP;
	722	sk_write(s, b, 2);
	723	break;
	724	case TS_SUSP:
	725	b[1] = SUSP;
	726	sk_write(s, b, 2);
	727	break;
	728	case TS_EOR:
	729	b[1] = EOR;
	730	sk_write(s, b, 2);
	731	break;
	732	case TS_EOF:
	733	b[1] = xEOF;
	734	sk_write(s, b, 2);
	735	break;
374330e2	736	case TS_SYNCH:
32874aea	737	b[1] = DM;
	738	sk_write(s, b, 1);
	739	sk_write_oob(s, b + 1, 1);
	740	break;
684d367c	741	case TS_RECHO:
	742	if (o_echo.state == INACTIVE \|\| o_echo.state == REALLY_INACTIVE) {
	743	o_echo.state = REQUESTED;
32874aea	744	send_opt(o_echo.send, o_echo.option);
684d367c	745	}
	746	break;
	747	case TS_LECHO:
	748	if (o_echo.state == ACTIVE) {
	749	o_echo.state = REQUESTED;
32874aea	750	send_opt(o_echo.nsend, o_echo.option);
684d367c	751	}
374330e2	752	break;
32874aea	753	case TS_PING:
ec55b220	754	if (o_they_sga.state == ACTIVE) {
32874aea	755	b[1] = NOP;
32874aea	756	sk_write(s, b, 2);
ec55b220	757	}
32874aea	758	break;
374330e2	759	}
	760	}
	761
32874aea	762	static Socket telnet_socket(void)
	763	{
	764	return s;
	765	}
8ccc75b0	766
32874aea	767	static int telnet_sendok(void)
	768	{
	769	return 1;
	770	}
4017be6d	771
32874aea	772	static int telnet_ldisc(int option)
	773	{
	774	if (option == LD_ECHO)
	775	return echoing;
	776	if (option == LD_EDIT)
	777	return editing;
0965bee0	778	return FALSE;
	779	}
	780
374330e2	781	Backend telnet_backend = {
374330e2	782	telnet_init,
374330e2	783	telnet_send,
374330e2	784	telnet_size,
4017be6d	785	telnet_special,
8ccc75b0	786	telnet_socket,
97db3be4	787	telnet_sendok,
0965bee0	788	telnet_ldisc,
97db3be4	789	23
374330e2	790	};