/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ typedef struct Opt	Opt; int debug;#define DPRINT if(debug)fprint enum{	/* control characters */	Se=		240,		/* end subnegotiation */	NOP=		241,	Mark=		242,		/* data mark */	Break=		243,	Interrupt=	244,	Abort=		245,		/* TENEX ^O */	AreYouThere=	246,	Erasechar=	247,		/* erase last character */	Eraseline=	248,		/* erase line */	GoAhead=	249,		/* half duplex clear to send */	Sb=		250,		/* start subnegotiation */	Will=		251,	Wont=		252,	Do=		253,	Dont=		254,	Iac=		255, 	/* options */	Binary=		0,	Echo,	SGA,	Stat,	Timing,	Det,	Term,	EOR,	Uid,	Outmark,	Ttyloc,	M3270,	Padx3,	Window,	Speed,	Flow,	Line,	Xloc,	Extend,}; struct Opt{	char	*name;	int	code;	char	noway;		int	(*change)(Biobuf*, int);	/* routine for status change */	int	(*sub)(Biobuf*, uchar*, int n);	/* routine for subnegotiation */	char	remote;				/* remote value */	char	local;				/* local value */}; Opt opt[] ={[Binary]	{ "binary",		0,  0, },[Echo]		{ "echo",		1,  0, },[SGA]		{ "suppress Go Ahead",	3,  0, },[Stat]		{ "status",		5,  1, },[Timing]	{ "timing",		6,  1, },[Det]		{ "det",		20, 1, },[Term]		{ "terminal",		24, 0, },[EOR]		{ "end of record",	25, 1, },[Uid]		{ "uid",		26, 1, },[Outmark]	{ "outmark",		27, 1, },[Ttyloc]	{ "ttyloc",		28, 1, },[M3270]		{ "3270 mode",		29, 1, },[Padx3]		{ "pad x.3",		30, 1, },[Window]	{ "window size",	31, 1, },[Speed]		{ "speed",		32, 1, },[Flow]		{ "flow control",	33, 1, },[Line]		{ "line mode",		34, 1, },[Xloc]		{ "X display loc",	35, 0, },[Extend]	{ "Extended",		255, 1, },}; int	control(Biobuf*, int);Opt*	findopt(int);int	will(Biobuf*);int	wont(Biobuf*);int	doit(Biobuf*);int	dont(Biobuf*);int	sub(Biobuf*);int	send2(int, int, int);int	send3(int, int, int, int);int	sendnote(int, char*);void	fatal(char*, void*, void*);char*	syserr(void);int	wasintr(void);long	iread(int, void*, int);long	iwrite(int, void*, int);void	binit(Biobuf*, int);void	berase(Biobuf*);void	bkill(Biobuf*); /* *  parse telnet control messages */intcontrol(Biobuf *bp, int c){	if(c < 0)		return -1;	switch(c){	case AreYouThere:		fprint(Bfildes(bp), "Plan 9 telnet, version 1\r\n");		break;	case Sb:		return sub(bp);	case Will:		return will(bp);	case Wont:		return wont(bp);	case Do:		return doit(bp);	case Dont:		return dont(bp);	case Se:		fprint(2, "telnet: SE without an SB\n");		break;	default:		break;	}	return 0;} Opt*findopt(int c){	Opt *o; 	for(o = opt; o <= &opt[Extend]; o++)		if(o->code == c)			return o;	return 0;} intwill(Biobuf *bp){	Opt *o;	int c;	int rv = 0; 	c = Bgetc(bp);	if(c < 0)		return -1;	DPRINT(2, "will %d\n", c);	o = findopt(c);	if(o == 0){		send3(Bfildes(bp), Iac, Dont, c);		return 0;	}	if(o->noway)		send3(Bfildes(bp), Iac, Dont, c);	else if(o->remote == 0)		rv |= send3(Bfildes(bp), Iac, Do, c);	if(o->remote == 0){		if(o->change)			rv |= (*o->change)(bp, Will);	}	o->remote = 1;	return rv;} intwont(Biobuf *bp){	Opt *o;	int c;	int rv = 0; 	c = Bgetc(bp);	if(c < 0)		return -1;	DPRINT(2, "wont %d\n", c);	o = findopt(c);	if(o == 0)		return 0;	if(o->remote){		if(o->change)			rv |= (*o->change)(bp, Wont);		rv |= send3(Bfildes(bp), Iac, Dont, c);	}	o->remote = 0;	return rv;} intdoit(Biobuf *bp){	Opt *o;	int c;	int rv = 0; 	c = Bgetc(bp);	if(c < 0)		return -1;	DPRINT(2, "do %d\n", c);	o = findopt(c);	if(o == 0 || o->noway){		send3(Bfildes(bp), Iac, Wont, c);		return 0;	}	if(o->noway)		return 0;	if(o->local == 0){		if(o->change)			rv |= (*o->change)(bp, Do);		rv |= send3(Bfildes(bp), Iac, Will, c);	}	o->local = 1;	return rv;} intdont(Biobuf *bp){	Opt *o;	int c;	int rv = 0; 	c = Bgetc(bp);	if(c < 0)		return -1;	DPRINT(2, "dont %d\n", c);	o = findopt(c);	if(o == 0)		return 0;	if(o->noway)		return 0;	if(o->local){		o->local = 0;		if(o->change)			rv |= (*o->change)(bp, Dont);		rv |= send3(Bfildes(bp), Iac, Wont, c);	}	o->local = 0;	return rv;} /* read in a subnegotiation message and pass it to a routine for that option */intsub(Biobuf *bp){	uchar subneg[128];	uchar *p;	Opt *o;	int c; 	p = subneg;	for(;;){		c = Bgetc(bp);		if(c == Iac){			c = Bgetc(bp);			if(c == Se)				break;			if(p < &subneg[sizeof(subneg)])				*p++ = Iac;		}		if(c < 0)			return -1;		if(p < &subneg[sizeof(subneg)])			*p++ = c;	}	if(p == subneg)		return 0;	DPRINT(2, "sub %d %d n = %d\n", subneg[0], subneg[1], (int)(p - subneg - 1));	o = findopt(subneg[0]);	if(o == 0 || o->sub == 0)		return 0;	return (*o->sub)(bp, subneg+1, p - subneg - 1);} voidsendd(int c0, int c1){	char *t = 0; 	switch(c0){	case Will:		t = "Will";		break;	case Wont:		t = "Wont";		break;	case Do:		t = "Do";		break;	case Dont:		t = "Dont";		break;	}	if(t)		DPRINT(2, "r %s %d\n", t, c1);} intsend2(int f, int c0, int c1){	uchar buf[2]; 	buf[0] = c0;	buf[1] = c1;	return iwrite(f, buf, 2) == 2 ? 0 : -1;} intsend3(int f, int c0, int c1, int c2){	uchar buf[3]; 	buf[0] = c0;	buf[1] = c1;	buf[2] = c2;	sendd(c1, c2);	return iwrite(f, buf, 3) == 3 ? 0 : -1;} intsendnote(int pid, char *msg){	int fd;	char name[128]; 	sprint(name, "/proc/%d/note", pid);	fd = open(name, OWRITE);	if(fd < 0)		return -1;	if(write(fd, msg, strlen(msg))!=strlen(msg))		return -1;	return close(fd);} voidfatal(char *fmt, void *a0, void *a1){	char buf[128]; 	sprint(buf, fmt, a0, a1);	fprint(2, "%s: %s\n", argv0, buf);	exits(buf);} char*syserr(void){	static char err[ERRMAX]; 	errstr(err, sizeof err);	return err;} intwasintr(void){	return strcmp(syserr(), "interrupted") == 0;} longiread(int f, void *a, int n){	long m; 	for(;;){		m = read(f, a, n);		if(m >= 0 || !wasintr())			break;	}	return m;} longiwrite(int f, void *a, int n){	long m; 	m = write(f, a, n);	if(m < 0 && wasintr())		return n;	return m;}