/* Internet Telnet client
 * Copyright 1991 Phil Karn, KA9Q
 */
#include <stdio.h>
#ifdef	__TURBOC__
#include <io.h>
#include <fcntl.h>
#endif
#include "global.h"
#include "mbuf.h"
#include "socket.h"
#include "telnet.h"
#include "session.h"
#include "proc.h"
#include "tty.h"
#include "commands.h"
#include "netuser.h"

static int filemode __ARGS((FILE *fp,int mode));
#define	CTLZ	26

int Refuse_echo = 0;
int Tn_cr_mode = 0;    /* if true turn <cr> to <cr-nul> */

#ifdef	DEBUG
char *T_options[] = {
	"Transmit Binary",
	"Echo",
	"",
	"Suppress Go Ahead",
	"",
	"Status",
	"Timing Mark"
};
#endif

/* Execute user telnet command */
int
dotelnet(argc,argv,p)
int argc;
char *argv[];
void *p;
{
	struct session *sp;
	struct sockaddr_in fsocket;

	/* Allocate a session descriptor */
	if((sp = newsession(argv[1],TELNET)) == NULLSESSION){
		tprintf("Too many sessions\n");
		return 1;
	}
	fsocket.sin_family = AF_INET;
	if(argc < 3)
		fsocket.sin_port = IPPORT_TELNET;
	else
		fsocket.sin_port = atoi(argv[2]);

	tprintf("Resolving %s... ",sp->name);
	if((fsocket.sin_addr.s_addr = resolve(sp->name)) == 0){
		tprintf(Badhost,sp->name);
		keywait(NULLCHAR,1);
		freesession(sp);
		return 1;
	}
	if((sp->s = socket(AF_INET,SOCK_STREAM,0)) == -1){
		tprintf("Can't create socket\n");
		keywait(NULLCHAR,1);
		freesession(sp);
		return 1;
	}
	return tel_connect(sp,(char *)&fsocket,SOCKSIZE);
}
/* Generic interactive connect routine, used by Telnet, AX.25, NET/ROM */
int
tel_connect(sp,fsocket,len)
struct session *sp;
char *fsocket;
int len;
{
	unsigned int index;
	struct telnet tn;

	index = sp - Sessions;
	memset((char *)&tn,0,sizeof(tn));
	tn.eolmode = Tn_cr_mode;
	tn.session = sp;	/* Upward pointer */
	sp->cb.telnet = &tn;	/* Downward pointer */
	sockmode(sp->s,SOCK_ASCII);	/* Default to ascii mode */

	tprintf("Trying %s...\n",psocket((struct sockaddr *)fsocket));
	if(connect(sp->s,fsocket,len) == -1){
  		tprintf("%s session %u failed: %s errno %d\n",
		 Sestypes[sp->type], index, sockerr(sp->s),errno);

		keywait(NULLCHAR,1);
		freesession(sp);
		return 1;
	}
	tprintf("%s session ",Sestypes[sp->type]);
	tprintf("%u connected to %s\n",index,sp->name);
	tnrecv(&tn);
	return 0;
}

/* Telnet input routine, common to both telnet and ttylink */
void
tnrecv(tn)
struct telnet *tn;
{
	int c,s,index;
	struct session *sp;
	char *cp;

	sp = tn->session;
	s = sp->s;

	index = sp - Sessions;

	/* Fork off the transmit process */
	sp->proc1 = newproc("tel_out",1024,tel_output,0,tn,NULL,0);

	/* Process input on the connection */
	while((c = recvchar(s)) != -1){
		if(c != IAC){
			/* Ordinary character */
			if(!tn->remote[TN_TRANSMIT_BINARY])
				c &= 0x7f;

			tputc((char)c);
			continue;
		}
		/* IAC received, get command sequence */
		c = recvchar(s);
		switch(c){
		case WILL:
			c = recvchar(s);
			willopt(tn,c);
			break;
		case WONT:
			c = recvchar(s);
			wontopt(tn,c);
			break;
		case DO:
			c = recvchar(s);
			doopt(tn,c);
			break;
		case DONT:
			c = recvchar(s);
			dontopt(tn,c);
			break;
		case IAC:	/* Escaped IAC */
			tputc(IAC);
			break;
		}
	}
quit:	/* A close was received from the remote host.
	 * Notify the user, kill the output task and wait for a response
	 * from the user before freeing the session.
	 */
	sockmode(sp->output,SOCK_ASCII); /* Restore newline translation */
	cp = sockerr(s);
	tprintf("%s session %u", Sestypes[sp->type],index);
	tprintf(" closed: %s\n", cp != NULLCHAR ? cp : "EOF");
	killproc(sp->proc1);
	sp->proc1 = NULLPROC;
	close_s(sp->s);
	sp->s = -1;
	keywait(NULLCHAR,1);
	freesession(sp);
}

/* User telnet output task, started by user telnet command */
void
tel_output(unused,tn1,p)
int unused;
void *tn1;
void *p;
{
	struct session *sp;
	int c;
	struct telnet *tn;

	tn = (struct telnet *)tn1;
	sp = tn->session;

	/* Send whatever's typed on the terminal */
	while((c = recvchar(sp->input)) != EOF){
		usputc(sp->s,(char)c);
		if(!tn->remote[TN_ECHO] && sp->record != NULLFILE)
			putc(c,sp->record);

		/* By default, output is transparent in remote echo mode.
		 * If eolmode is set, turn a cr into cr-null.
		 * This can only happen when in remote echo (raw) mode, since
		 * the tty driver normally maps \r to \n in cooked mode.
		 */
		if(c == '\r' && tn->eolmode)
			usputc(sp->s,'\0');

		if(tn->remote[TN_ECHO])
			usflush(sp->s);
	}
	/* Make sure our parent doesn't try to kill us after we exit */
	sp->proc1 = NULLPROC;
}
int
doecho(argc,argv,p)
int argc;
char *argv[];
void *p;
{
	if(argc < 2){
		if(Refuse_echo)
			tprintf("Refuse\n");
		else
			tprintf("Accept\n");
	} else {
		if(argv[1][0] == 'r')
			Refuse_echo = 1;
		else if(argv[1][0] == 'a')
			Refuse_echo = 0;
		else
			return -1;
	}
	return 0;
}
/* set for unix end of line for remote echo mode telnet */
int
doeol(argc,argv,p)
int argc;
char *argv[];
void *p;
{
	if(argc < 2){
		if(Tn_cr_mode)
			tprintf("null\n");
		else
			tprintf("standard\n");
	} else {
		if(argv[1][0] == 'n')
			Tn_cr_mode = 1;
		else if(argv[1][0] == 's')
			Tn_cr_mode = 0;
		else {
			tprintf("Usage: %s [standard|null]\n",argv[0]);
			return -1;
		}
	}
	return 0;
}

/* The guts of the actual Telnet protocol: negotiating options */
void
willopt(tn,opt)
struct telnet *tn;
int opt;
{
	int ack;

#ifdef	DEBUG
	printf("recv: will ");
	if(uchar(opt) <= NOPTIONS)
		printf("%s\n",T_options[opt]);
	else
		printf("%u\n",opt);
#endif
	
	switch(uchar(opt)){
	case TN_TRANSMIT_BINARY:
	case TN_ECHO:
	case TN_SUPPRESS_GA:
		if(tn->remote[uchar(opt)] == 1)
			return;		/* Already set, ignore to prevent loop */
		if(uchar(opt) == TN_ECHO){
			if(Refuse_echo){
				/* User doesn't want to accept */
				ack = DONT;
				break;
			} else {
				/* Put tty into raw mode */
				tn->session->ttystate.edit = 0;
				tn->session->ttystate.echo = 0;
				sockmode(tn->session->s,SOCK_BINARY);
				sockmode(tn->session->input,SOCK_BINARY);
				sockmode(tn->session->output,SOCK_BINARY);
				if(tn->session->record != NULLFILE)
					filemode(tn->session->record,SOCK_BINARY);

			}
		}
		tn->remote[uchar(opt)] = 1;
		ack = DO;			
		break;
	default:
		ack = DONT;	/* We don't know what he's offering; refuse */
	}
	answer(tn,ack,opt);
}
void
wontopt(tn,opt)
struct telnet *tn;
int opt;
{
#ifdef	DEBUG
	printf("recv: wont ");
	if(uchar(opt) <= NOPTIONS)
		printf("%s\n",T_options[uchar(opt)]);
	else
		printf("%u\n",uchar(opt));
#endif
	if(uchar(opt) <= NOPTIONS){
		if(tn->remote[uchar(opt)] == 0)
			return;		/* Already clear, ignore to prevent loop */
		tn->remote[uchar(opt)] = 0;
		if(uchar(opt) == TN_ECHO){
			/* Put tty into cooked mode */
			tn->session->ttystate.edit = 1;
			tn->session->ttystate.echo = 1;
			sockmode(tn->session->s,SOCK_ASCII);
			sockmode(tn->session->input,SOCK_ASCII);
			sockmode(tn->session->output,SOCK_ASCII);
			if(tn->session->record != NULLFILE)
				filemode(tn->session->record,SOCK_ASCII);
		}
	}
	answer(tn,DONT,opt);	/* Must always accept */
}
void
doopt(tn,opt)
struct telnet *tn;
int opt;
{
	int ack;

#ifdef	DEBUG
	printf("recv: do ");
	if(uchar(opt) <= NOPTIONS)
		printf("%s\n",T_options[uchar(opt)]);
	else
		printf("%u\n",uchar(opt));
#endif
	switch(uchar(opt)){
#ifdef	FUTURE	/* Use when local options are implemented */
		if(tn->local[uchar(opt)] == 1)
			return;		/* Already set, ignore to prevent loop */
		tn->local[uchar(opt)] = 1;
		ack = WILL;
		break;
#endif
	default:
		ack = WONT;	/* Don't know what it is */
	}
	answer(tn,ack,opt);
}
void
dontopt(tn,opt)
struct telnet *tn;
int opt;
{
#ifdef	DEBUG
	printf("recv: dont ");
	if(uchar(opt) <= NOPTIONS)
		printf("%s\n",T_options[uchar(opt)]);
	else
		printf("%u\n",uchar(opt));
#endif
	if(uchar(opt) <= NOPTIONS){
		if(tn->local[uchar(opt)] == 0){
			/* Already clear, ignore to prevent loop */
			return;
		}
		tn->local[uchar(opt)] = 0;
	}
	answer(tn,WONT,opt);
}
void
answer(tn,r1,r2)
struct telnet *tn;
int r1,r2;
{
	char s[3];

#ifdef	DEBUG
	switch(r1){
	case WILL:
		printf("sent: will ");
		break;
	case WONT:
		printf("sent: wont ");
		break;
	case DO:
		printf("sent: do ");
		break;
	case DONT:
		printf("sent: dont ");
		break;
	}
	if(r2 <= NOPTIONS)
		printf("%s\n",T_options[r2]);
	else
		printf("%u\n",r2);
#endif

	s[0] = IAC;
	s[1] = r1;
	s[2] = r2;
	send(tn->session->s,s,3,0);
}
#ifdef	__TURBOC__
/* Set end-of-line translation mode on file */
static int
filemode(fp,mode)
FILE *fp;
int mode;
{
	int omode;

	if(fp == NULLFILE)
		return -1;

	if(fp->flags & _F_BIN)
		omode = SOCK_BINARY;
	else
		omode = SOCK_ASCII;

	switch(mode){
	case SOCK_BINARY:
		fp->flags = _F_BIN;
		setmode(fileno(fp),O_BINARY);
		break;
	case SOCK_ASCII:
		fp->flags &= ~_F_BIN;
		setmode(fileno(fp),O_TEXT);
		break;
	}
	return omode;
}
#else
static int
filemode(fp,mode)
FILE *fp;
int mode;
{
	return 0;
}
#endif