/*======================================================================*
 *                                                                      *
 *            Program to process ExpressNET! Calls                      *
 *                                                                      *
 *======================================================================*/

#version        $50
#reserve        6
#copyright      "Nhshost.cmd    Written By Stephen J. Carden Copyright 1995 K-Products"
#address        $7000

#include        runtime.h
#include        bbs_pro.h

#define         DISK2       2
#define         C_MODEM     5
#define         _ACK_       6
#define         _NAK_       24
#define         _EOT_       4


char    hs_buffer [40];

char    callfn [40];

int     node;
char    timeout;


main()
{
    strcpy (callfn, "Dx:>PRO>NETWORK>X_");
    callfn [2] = s_netdr;
    printf ("%c%e%e%e%e%e __ExpressNET! Hi Speed Host Activated__%e%e",125);
    if (handshake()) {
	invoker = $C0;
	strcpy (parm1, callfn);
	chain ("NSRXFER");
    }
    chain ("WAITCALL");
}


/*==================================================================*
 *  handshake - Attempt to handshake with the host system.          *
 *                                                                  *
 *              Returns:  0 - unable to establish connection.       *
 *                        1 - connected, chain to netmodem.         *
 *==================================================================*/

handshake()
{
    byte file_here, cksum, valid;
    char ch, temp [10];
    byte x, tries;
    int  usernum, tempnum;

    trans = 0;
    printf ("%eHandshaking with remote caller...");
    seconds = 0;
    ch = 0;
    purge_modem();
    do {                                        /* wait for $fc to start  */
	if (bytes_in())
	    ch = getd (C_MODEM);
    } while (ch != $fc && seconds < 20);
    if (ch != $fc)
	return (0);
    seconds = 0;
    valid   = 0;
    tries   = 0;
    do {
	++tries;
	purge_modem();
	putd (C_MODEM, _NAK_);                  /* request header   */
	cksum = 0;
	for (x = 0; x < 21; ++x) {              /* 21-byte header   */
	    hs_buffer [x] = getx (3);
	    if (timeout) break;
	}
	if (timeout == 0) {
	    cksum = 0;
	    for (x = 0; x < 20; ++x)
		cksum = cksum + hs_buffer [x];
	    if (cksum == hs_buffer [20]) {
		node    = hs_buffer [17] * 256 + hs_buffer [16];
		usernum = hs_buffer [19] * 256 + hs_buffer [18];
		printf("%e%e Node: %d%e", node);
		printf(" User: %d%e", usernum);
		printf("Pword: %s%e", hs_buffer);
		MIOsuspend();
		if (open_ulog() < 128) {
		    if (read_user (usernum) < 128) {
			if (strcmpi(t_pword, hs_buffer) != 0)
			    printf("%eInvalid password!%e");
			else {
			    tempnum = valc (t_name);
			    if (tempnum == node)
				valid = 1;
			    else
				printf("%eInvalid node access!%e");
			 }
		    }
		}
		close_ulog();
		MIOresume();
	    }
	}
    } while (valid == 0 && tries < 10);
    if (tries > 9)                             /* couldn't handshake   */
	return (0);
    printf("%e%eNode #%d online!%e", node);
    strc (node, temp);
    strcat (callfn, temp);                      /* complete filename    */
    strcat (callfn, ".ARC");
    MIOsuspend();
    file_here = 1;
    if (open (DISK2, callfn, 4, 0) != OK)       /* file to send?    */
	file_here = 0;
    close (DISK2);
    MIOresume();
    if (file_here == 0) {
	printf("%e%eNo packet to send...%e", node);
	putd (C_MODEM, _EOT_);
	putd (C_MODEM, _EOT_);
	putd (C_MODEM, _EOT_);
	putd (C_MODEM, _EOT_);
	putd (C_MODEM, _EOT_);
	return (0);
     }
    else {
	putd (C_MODEM, _ACK_);
	putd (C_MODEM, _ACK_);
	putd (C_MODEM, _ACK_);
	putd (C_MODEM, _ACK_);
	return (1);
    }
}


/*==================================================================*
 *  getx  -  get input from modem with "secs" timeout.              *
 *==================================================================*/

getx (byte secs)
{
    timeout = 0;
    seconds = 0;
    do {
	if (bytes_in())
	    return (getd (C_MODEM));
    } while (seconds < secs);
    timeout = 1;
}



/*==================================================================*
 *  purge_modem - remove all incoming data from the modem           *
 *==================================================================*/

purge_modem()
{
    char ch;
    while (bytes_in())
	ch = getd (C_MODEM);
}