zm.c

Debian Linux下的通讯程序

/*
 *   Z M . C
 *    ZMODEM protocol primitives
 *    05-09-88  Chuck Forsberg Omen Technology Inc
 *
 * Entry point Functions:
 *	zsbhdr(type, hdr) send binary header
 *	zshhdr(type, hdr) send hex header
 *	zgethdr(hdr, eflag) receive header - binary or hex
 *	zsdata(buf, len, frameend) send data
 *	zrdata(buf, len) receive data
 *	stohdr(pos) store position data in Txhdr
 *	long rclhdr(hdr) recover position offset from header
 */

#ifndef CANFDX
#include "zmodem.h"
int Rxtimeout = 100;		/* Tenths of seconds to wait for something */
#endif

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

static lastsent;	/* Last char we sent */
static Not8bit;		/* Seven bits seen on header */

static char *frametypes[] = {
	"Carrier Lost",		/* -3 */
	"TIMEOUT",		/* -2 */
	"ERROR",		/* -1 */
#define FTOFFSET 3
	"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 */
};

static char badcrc[] = "Bad CRC";

static void zsendline_init(char *);
/*
 * Send character c with ZMODEM escape sequence encoding.
 *  Escape XON, XOFF. Escape CR following @ (Telenet net escape)
 */
void
#ifdef __GNUC__
	/* this saves about one function call per 4 Bytes */
inline
#endif
zsendline(int c)
{
	static int last_esc=-2;
	static char tab[256];
	if (Zctlesc!=last_esc) {
		zsendline_init(tab);
		last_esc=Zctlesc;
	}

	switch(tab[(unsigned) (c&=0377)])
	{
	case 0: 
		xsendline(lastsent = c); 
		break;
	case 1:
		xsendline(ZDLE);
		c ^= 0100;
		xsendline(lastsent = c);
		break;
	case 2:
		if ((lastsent & 0177) != '@') {
			xsendline(lastsent = c);
		} else {
			xsendline(ZDLE);
			c ^= 0100;
			xsendline(lastsent = c);
		}
		break;
	}
}

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

	vfile("zsbhdr: %s %lx", frametypes[type+FTOFFSET], rclhdr(hdr));
	if (type == ZDATA)
		for (n = Znulls; --n >=0; )
			xsendline(0);

	xsendline(ZPAD); xsendline(ZDLE);

	if (Crc32t=Txfcs32)
		zsbh32(hdr, type);
	else {
		xsendline(ZBIN); zsendline(type); crc = updcrc(type, 0);

		for (n=4; --n >= 0; ++hdr) {
			zsendline(*hdr);
			crc = updcrc((0377& *hdr), crc);
		}
		crc = updcrc(0,updcrc(0,crc));
		zsendline(crc>>8);
		zsendline(crc);
	}
	if (type != ZDATA)
		flushmo();
}


/* Send ZMODEM binary header hdr of type type */
zsbh32(hdr, type)
register char *hdr;
{
	register int n;
	register unsigned long crc;

	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;
	}
}

/* Send ZMODEM HEX header hdr of type type */
zshhdr(type, hdr)
register char *hdr;
{
	register int n;
	register unsigned short crc;
	char s[30];
	size_t len;

	vfile("zshhdr: %s %lx", frametypes[type+FTOFFSET], rclhdr(hdr));
	s[0]=ZPAD;
	s[1]=ZPAD;
	s[2]=ZDLE;
	s[3]=ZHEX;
	zputhex(type,s+4);
	len=6;
	Crc32t = 0;

	crc = updcrc(type, 0);
	for (n=4; --n >= 0; ++hdr) {
		zputhex(*hdr,s+len); 
		len += 2;
		crc = updcrc((0377 & *hdr), crc);
	}
	crc = updcrc(0,updcrc(0,crc));
	zputhex(crc>>8,s+len); 
	zputhex(crc,s+len+2);
	len+=4;

	/* Make it printable on remote machine */
	s[len++]=015;
	s[len++]=0212;
	/*
	 * Uncork the remote in case a fake XOFF has stopped data flow
	 */
	if (type != ZFIN && type != ZACK)
	{
		s[len++]=021;
	}
	flushmo();
	write(1,s,len);
}

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

	vfile("zsdata: %d %s", length, Zendnames[frameend-ZCRCE&3]);
	if (Crc32t)
		zsda32(buf, length, frameend);
	else {
		crc = 0;
		for (;--length >= 0; ++buf) {
			zsendline(*buf); crc = updcrc((0377 & *buf), crc);
		}
		xsendline(ZDLE); xsendline(frameend);
		crc = updcrc(frameend, crc);

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

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

	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;) {
		c=(int) crc;
		if (c & 0140)
			xsendline(lastsent = c);
		else
			zsendline(c);
		crc >>= 8;
	}
}

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

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

	crc = Rxcount = 0;  end = buf + length;
	while (buf <= end) {
		if ((c = zdlread()) & ~0377) {
crcfoo:
			switch (c) {
			case GOTCRCE:
			case GOTCRCG:
			case GOTCRCQ:
			case GOTCRCW:
				crc = updcrc((d=c)&0377, crc);
				if ((c = zdlread()) & ~0377)
					goto crcfoo;
				crc = updcrc(c, crc);
				if ((c = zdlread()) & ~0377)
					goto crcfoo;
				crc = updcrc(c, crc);
				if (crc & 0xFFFF) {
					zperr(badcrc);
					return ERROR;
				}
				Rxcount = length - (end - buf);
				vfile("zrdata: %d  %s", Rxcount,
				 Zendnames[d-GOTCRCE&3]);
				return d;
			case GOTCAN:
				zperr("Sender Canceled");
				return ZCAN;
			case TIMEOUT:
				zperr("TIMEOUT");
				return c;
			default:
				zperr("Bad data subpacket");
				return c;
			}
		}
		*buf++ = c;
		crc = updcrc(c, crc);
	}
	zperr("Data subpacket too long");
	return ERROR;
}

zrdat32(buf, length)
register char *buf;
{
	register int c;
	register unsigned long crc;
	register char *end;
	register int d;


	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) {
					zperr(badcrc);
					return ERROR;
				}
				Rxcount = length - (end - buf);
				vfile("zrdat32: %d %s", Rxcount,
				 Zendnames[d-GOTCRCE&3]);
				return d;
			case GOTCAN:
				zperr("Sender Canceled");
				return ZCAN;
			case TIMEOUT:
				zperr("TIMEOUT");
				return c;
			default:
				zperr("Bad data subpacket");
				return c;
			}
		}
		*buf++ = c;
		crc = UPDC32(c, crc);
	}
	zperr("Data subpacket too long");
	return ERROR;
}


/*
 * Read a ZMODEM header to hdr, either binary or hex.
 *  eflag controls local display of non zmodem characters:
 *	0:  no display
 *	1:  display printing characters only
 *	2:  display all non ZMODEM characters
 *  On success, set Zmodem to 1, set Rxpos and return type of header.
 *   Otherwise return negative on error.
 *   Return ERROR instantly if ZCRCW sequence, for fast error recovery.
 */
zgethdr(hdr, eflag)
char *hdr;
{
	register int c, n, cancount;

	n = Zrwindow + Baudrate;	/* Max bytes before start of frame */
	Rxframeind = Rxtype = 0;

startover:
	cancount = 5;
again:
	/* Return immediate ERROR if ZCRCW sequence seen */
	switch (c = readline(Rxtimeout)) {
	case RCDO:
	case TIMEOUT:
		goto fifi;
	case CAN:
gotcan:
		if (--cancount <= 0) {
			c = ZCAN; goto fifi;
		}
		switch (c = readline(1)) {
		case TIMEOUT:
			goto again;
		case ZCRCW: