zmodem.c

一个通讯程序源码

#if defined(WHT) && !defined(SHOW_ZHDR_TYPE)
#define SHOW_ZHDR_TYPE
#endif
/*+-------------------------------------------------------------------------
	zmodem.c - ZMODEM protocol primitives
    based on code by Chuck Forsberg

  Defined functions:
	noxrd7()
	rclhdr(hdr)
	stohdr(pos)
	zdlread()
	zgeth1()
	zgethdr(hdr,eflag)
	zgethex()
	zputhex(c)
	zrbhdr(hdr)
	zrbhdr32(hdr)
	zrdat32(buf,length)
	zrdata(buf,length)
	zrhhdr(hdr)
	zsbh32(type,hdr)
	zsbhdr(type,hdr)
	zsda32(buf,length,frameend)
	zsdata(buf,length,frameend)
	zsendline(c)
	zshhdr(type,hdr)

--------------------------------------------------------------------------*/
/*+:EDITS:*/
/*:09-10-1992-14:00-wht@n4hgf-ECU release 3.20 */
/*:08-22-1992-15:39-wht@n4hgf-ECU release 3.20 BETA */
/*:07-25-1991-12:59-wht@n4hgf-ECU release 3.10 */
/*:08-14-1990-20:41-wht@n4hgf-ecu3.00-flush old edit history */

#include "zmodem.h"			/* wht */

extern char s128[];				/* wht */
extern int Zctlesc;				/* wht */
extern int Zmodem;				/* wht */
extern long cr3tab[];			/* wht */
extern unsigned Baudrate;		/* wht */
extern unsigned short crctab[];	/* wht */

int Rxtimeout = 100;		/* Tenths of seconds to wait for something */

#if !defined(UNSL)
#define UNSL
#endif

static lastsent;	/* Last char we sent */
static evenp;		/* Even parity seen on header */

/* Globals used by ZMODEM functions */
char Attn[ZATTNLEN+1];	/* Attention string rx sends to tx on err */
char Rxhdr[4];		/* Received header */
char Txhdr[4];		/* Transmitted header */
int Crc32;		/* Display flag indicating 32 bit CRC being received */
int Crc32t;		/* Display flag indicating 32 bit CRC being sent */
int Rxcount;		/* Count of data bytes received */
int Rxframeind;		/* ZBIN ZBIN32,or ZHEX type of frame received */
int Rxtype;		/* Type of header received */
int Txfcs32;		/* TURE means send binary frames with 32 bit FCS */
int Zrwindow;	/* RX window size (controls garbage count) */
long Rxpos;	/* Received file position */
long Txpos;	/* Transmitted file position */

char *frametypes[] = {
	"Carrier Lost",		/* -3 */
	"TIMEOUT",			/* -2 */
	"ERROR",			/* -1 */
/* #define FTOFFSET 3 moved to zmodem.h */
	"ZRQINIT",
	"ZRINIT",
	"ZSINIT",
	"ZACK ",
	"ZFILE",
	"ZSKIP",
	"ZNAK ",
	"ZABORT",
	"ZFIN ",
	"ZRPOS",
	"ZDATA",
	"ZEOF ",
	"ZFERR",
	"ZCRC ",
	"ZCHALLENGE",
	"ZCOMPL",
	"ZCAN ",
	"ZFREECNT",
	"ZCOMMAND",
	"ZSTDERR",
	"xxxxx"
#define FRTYPES 22	/* Total number of frame types in this array */
	/*  not including psuedo negative entries */
};

/*
 * Send character c with ZMODEM escape sequence encoding.
 *  Escape XON,XOFF. Escape CR following @ (Telenet net escape)
 */
void
zsendline(c)
int c;
{

	/* Quick check for non control characters */
	if(c & 0140)
		xsendline(lastsent = c);
	else 
	{
		switch(c &= 0377)
		{
		case ZDLE:
			xsendline(ZDLE);
			xsendline(lastsent = (c ^= 0100));
			break;
		case 015:
		case 0215:
			if(!Zctlesc && (lastsent & 0177) != '@')
				goto sendit;
			/* **** FALL THRU TO **** */
		case 020:
		case 021:
		case 023:
		case 0220:
		case 0221:
		case 0223:
			xsendline(ZDLE);
			c ^= 0100;
sendit:
			xsendline(lastsent = c);
			break;
		default:
			if(Zctlesc && ! (c & 0140))
			{
				xsendline(ZDLE);
				c ^= 0100;
			}
			xsendline(lastsent = c);
		}
	}
}

static char masked[] = "8 bit transparent path required";
static char badcrc[] = "Bad CRC";

/* Send ZMODEM CRC-32 binary header hdr of type type */
void
zsbh32(type,hdr)
int type;
register char *hdr;
{
	register int n;
	register UNSL long crc;

	sprintf(s128,
#ifdef SHOW_ZHDR_TYPE
		"B32 %s %ld",
#else
		"hdr %s %ld",
#endif
		frametypes[type+FTOFFSET],rclhdr(hdr));
	report_last_txhdr(s128,0);
	report_tx_ind(1);
	xsendline(ZBIN32);  
	zsendline(type);
	crc = 0xFFFFFFFFL; 
	crc = UPDC32(type,crc);

	for(n=4; --n >= 0; ++hdr)
	{
		crc = UPDC32((0377 & *hdr),crc);
		zsendline(*hdr);
	}
	crc = ~crc;
	for(n=4; --n >= 0;)
	{
		zsendline((int)crc);
		crc >>= 8;
	}
	report_tx_ind(0);
}

/* Send ZMODEM binary header hdr of type type */
void
zsbhdr(type,hdr)
int type;
register unsigned char *hdr;
{
	register int n;
	register unsigned crc;

	xsendline(ZPAD); 
	xsendline(ZDLE);

	if(Crc32t=Txfcs32)
		zsbh32(type,hdr);
	else 
	{
		sprintf(s128,
#ifdef SHOW_ZHDR_TYPE
			"B16 %s %ld",
#else
			"hdr %s %ld",
#endif
			frametypes[type+FTOFFSET],rclhdr(hdr));
		report_last_txhdr(s128,0);
		report_tx_ind(1);

		xsendline(ZBIN); 
		zsendline(type); 
		crc = updcrc(type,0);

		for(n=4; --n >= 0; ++hdr)
		{
			zsendline(*hdr);
			crc = updcrc(*hdr,crc);
		}
		crc = updcrc(0,updcrc(0,crc));
		zsendline(crc>>8);
		zsendline(crc);
		report_tx_ind(0);
	}
	if(type != ZDATA)
		flushline();
}

/*
 * Send binary array buf of length length,with ending ZDLE sequence frameend
 */
static char *Zendnames[] = { "ZCRCE","ZCRCG","ZCRCQ","ZCRCW"};

void
zsda32(buf,length,frameend)
register char *buf;
int length;
int frameend;
{
	register int c;
	register UNSL long crc;

	sprintf(s128,
#ifdef SHOW_ZHDR_TYPE
		"D32 %s %d",
#else
		"data %s %d",
#endif
		Zendnames[frameend-ZCRCE&3],length);
	report_last_txhdr(s128,0);
	report_tx_ind(1);

	crc = 0xFFFFFFFFL;
	for(;--length >= 0; ++buf)
	{
		c = *buf & 0377;
		if(c & 0140)
			xsendline(lastsent = c);
		else
			zsendline(c);
		crc = UPDC32(c,crc);
	}
	xsendline(ZDLE); 
	xsendline(frameend);
	crc = UPDC32(frameend,crc);

	crc = ~crc;
	for(length=4; --length >= 0;)
	{
		zsendline((int)crc);  
		crc >>= 8;
	}
	report_tx_ind(0);
}

void
zsdata(buf,length,frameend)
register unsigned char *buf;
int length;
int frameend;
{
	register unsigned short crc;

	if(Crc32t)
		zsda32(buf,length,frameend);
	else 
	{
		sprintf(s128,
#ifdef SHOW_ZHDR_TYPE
			"D16 %s %d",
#else
			"data %s %d",
#endif
			Zendnames[frameend-ZCRCE&3],length);
		report_last_txhdr(s128,0);
		report_tx_ind(1);
		crc = 0;
		for(;--length >= 0; ++buf)
		{
			zsendline(*buf); 
			crc = updcrc(*buf,crc);
		}
		xsendline(ZDLE); 
		xsendline(frameend);
		crc = updcrc(frameend,crc);

		crc = updcrc(0,updcrc(0,crc));
		zsendline(crc>>8); 
		zsendline(crc);
		report_tx_ind(0);
	}
	if(frameend == ZCRCW)
	{
		xsendline(XON);  
		flushline();
	}

}

/* Send a byte as two hex digits */
void
zputhex(c)
register int c;
{
	static char digits[]	= "0123456789abcdef";

	sendline(digits[(c&0xF0)>>4]);
	sendline(digits[(c)&0xF]);
}

void
zshhdr(type,hdr)
int type;
register unsigned char *hdr;
{
	register int n;
	register unsigned short crc;


	sprintf(s128,
#ifdef SHOW_ZHDR_TYPE
		"HEX %s %ld",
#else
		"hdr %s %ld",
#endif
		frametypes[type+FTOFFSET],rclhdr(hdr));
	report_last_txhdr(s128,0);
	report_tx_ind(1);
	sendline(ZPAD); 
	sendline(ZPAD); 
	sendline(ZDLE); 
	sendline(ZHEX);
	zputhex(type);
	Crc32t = 0;

	crc = updcrc(type,0);
	for(n=4; --n >= 0; ++hdr)
	{
		zputhex(*hdr); 
		crc = updcrc(*hdr,crc);
/*		crc = updcrc((0377 & *hdr),crc);  original - wht */
	}
	crc = updcrc(0,updcrc(0,crc));
	zputhex(crc>>8); 
	zputhex(crc);

	/* Make it printable on remote machine */
	sendline(015); 
	sendline(012);
	/*
	 * Uncork the remote in case a fake XOFF has stopped data flow
	 */
	if(type != ZFIN && type != ZACK)
		sendline(021);
	flushline();
	report_tx_ind(0);
}

/*
 * Receive array buf of max length with ending ZDLE sequence
 *  and CRC.  Returns the ending character or error code.
 *  NB: On errors may store length+1 bytes!
 */
int
zrdat32(buf,length)
register char *buf;
int length;
{
	register int c;
	register UNSL long crc;
	register char *end;
	register int d;

	report_rx_ind(1);
	crc = 0xFFFFFFFFL;  
	Rxcount = 0;  
	end = buf + length;
	while(buf <= end)
	{
		if((c = zdlread()) & ~0377)
		{
crcfoo:
			switch(c)
			{
			case GOTCRCE:
			case GOTCRCG:
			case GOTCRCQ:
			case GOTCRCW:
				d = c;  
				c &= 0377;
				crc = UPDC32(c,crc);
				if((c = zdlread()) & ~0377)
					goto crcfoo;
				crc = UPDC32(c,crc);
				if((c = zdlread()) & ~0377)
					goto crcfoo;
				crc = UPDC32(c,crc);
				if((c = zdlread()) & ~0377)
					goto crcfoo;
				crc = UPDC32(c,crc);
				if((c = zdlread()) & ~0377)
					goto crcfoo;
				crc = UPDC32(c,crc);
				if(crc != 0xDEBB20E3)
				{
					report_str(badcrc,0);
					report_rx_ind(0);
					return(ERROR);
				}
				Rxcount = length - (end - buf);
				report_rxblklen(Rxcount);
				sprintf(s128,
#ifdef SHOW_ZHDR_TYPE
					"D32 %s %d",
#else
					"data %s %d",
#endif
					Zendnames[d-GOTCRCE&3],Rxcount);
				report_last_rxhdr(s128,0);
				report_rx_ind(0);
				return(d);
			case GOTCAN:
				report_str("Sender Canceled",1);
				report_rx_ind(0);
				return(ZCAN);
			case TIMEOUT:
				report_str("TIMEOUT",0);
				report_rx_ind(0);
				return(c);
			default:
				report_str("Bad data subpacket",0);
				report_rx_ind(0);
				return(c);
			}
		}
		*buf++ = c;
		crc = UPDC32(c,crc);
	}
	report_str("Data subpacket too long",0);
	report_rx_ind(0);
	return(ERROR);
}

int
zrdata(buf,length)
register char *buf;
int length;
{
	register int c;
	register unsigned short crc;
	register char *end;
	register int d;


	if(Rxframeind == ZBIN32)
		return(zrdat32(buf,length));

	report_rx_ind(1);
	crc = Rxcount = 0;  
	end = buf + length;
	while(buf <= end)
	{
		if((c = zdlread()) & ~0377)
		{
crcfoo:
			switch(c)
			{
			case GOTCRCE: