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XPRXModem
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dlink.c
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1991-08-26
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553 lines
/* dlink - data link transfer routines for bmodem */
/*
* by David Betz, BYTE Magazine/BIX
*
* statements involving bm_infoinit(), bm_info() added by Willy Langeveld for
* VLT
*
* ANSIsized and made re-entrant by Marc Boucher for XPR implementation.
*
* 91.08.13 [astp] Fixed pre-computed crc table, which I added 91.08.10 *sigh*
*/
#include <string.h>
#include <stdio.h>
#include "xprxmodem.h"
#include "proto-dlink.h"
#include "proto-xprxmodem.h"
#include "proto-callback.h"
#define WTYPE unsigned short
/* useful definitions */
#define TRUE 1
#define FALSE 0
/* protocol characters */
#define SOH 0x01 /* start of a 128 byte block */
#define STX 0x02 /* start of a 1024 byte block */
#define EOT 0x04 /* end of a complete file */
#define ACK 0x06 /* positive acknowledgement */
#define NAK 0x15 /* negative acknowledgement */
#define CAN 0x18 /* cancel transfer */
#define CRC 'C' /* CRC request (instead of NAK to start a
* transfer) */
/* routine status codes */
#define DT_EOF -1
#define DT_OK 1
/* number of times to retry */
#define RETRY 10
/* timeout loop counters */
#define STIME 4 /* timeout between characters of a packet */
#define LTIME 20 /* timeout waiting for an ACK/NAK */
#define XTIME 60 /* timeout waiting for initial NAK */
/* dlabort - wait for the line to clear */
static void dlabort(struct XPR_IO * IO)
{
int res;
do
res = md_get(IO, STIME);
while ((res != DT_TIME) && (res != DT_ERR));
}
/* chk_compute - compute the checksum */
static int chk_compute(unsigned char *buf, int len)
{
int chk, i;
for (chk = i = 0; i < len; ++i)
chk += buf[i];
return (chk & 0xFF);
}
#ifndef PRECOMPUTECRC
/* crc_compute - compute the CRC value */
static int crc_compute(unsigned char *buf, int len)
{
int crc, shifter, highbit, i;
buf[len++] = '\0';
buf[len++] = '\0';
for (crc = i = 0; i < len; ++i)
for (shifter = 0x80; shifter; shifter >>= 1) {
highbit = crc & 0x8000;
crc <<= 1;
crc |= (buf[i] & shifter ? 1 : 0);
if (highbit)
crc ^= 0x1021;
}
return (crc & 0xFFFF);
}
#else
/*
* Pre-computed CRC polynomials (crctab) by Mark G. Mendel, 7/86
* (Network Systems Corp.); Credit also due to Stephen Satchell
* (Satchell Evaluations) for the improved updcrc (crc_compute)
* function, and Chuck Forsberg (Omen Technology) who wrote RBSB.c
* which Stephen extracted the original CRC table & functions.
*/
static WTYPE crctab[256] = /* as calculated by initcrctab() */ {
0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
} ;
static WTYPE crc_compute(unsigned char *buf, int len)
{
register WTYPE crc = 0;
register unsigned char *cp = buf;
buf[len++] = '\0';
buf[len++] = '\0';
while( len-- ) {
crc = crctab[((crc >> 8) & 255)] ^ (crc << 8) ^ *cp++;
}
return( crc );
}
#endif
static char *blkchk[] =
{"Checksum", "CRC-16"};
static char *timefmt = "%02ld:%02ld:%02ld";
static void bm_info(struct XPR_IO * IO, int error)
{
long (*xupdate) (), (*xchkmisc) (void);
struct XPR_UPDATE xpru;
long secs, micros, elapsed;
char buff1[20], buff2[20];
int blksiz, Iblknum;
blksiz=IO->xpr_data->msglength;
Iblknum=IO->xpr_data->blknum;
xchkmisc = IO->xpr_chkmisc;
if (xchkmisc)
xchkmisc();
/*
* Calculate elapsed time in tenths of seconds
*/
CurrentTime(&secs, µs);
secs -= IO->xpr_data->startsecs;
micros -= IO->xpr_data->startmics;
elapsed = (secs * 10L) + (micros / 100000L);
/*
* Always update data rate and elapsed time
*/
xpru.xpru_updatemask = XPRU_DATARATE | XPRU_ELAPSEDTIME;
sprintf(buff1, timefmt, secs / 3600L, (secs / 60L) % 60L, secs % 60L);
xpru.xpru_elapsedtime = buff1;
if (elapsed)
xpru.xpru_datarate = ((long) blksiz * Iblknum * 10L) / elapsed;
else
xpru.xpru_datarate = 0;
/*
* If we know the file size and the data rate we can compute the
* estimated time.
*/
if (IO->xpr_data->filsiz) {
if (xpru.xpru_datarate) {
xpru.xpru_updatemask |= XPRU_EXPECTTIME;
secs = IO->xpr_data->filsiz / xpru.xpru_datarate;
sprintf(buff2, timefmt, secs / 3600L, (secs / 60L) % 60L, secs % 60L);
xpru.xpru_expecttime = buff2;
}
}
/*
* On error, timeout or otherwise, update different things
*/
if (error == DT_ERR) {
IO->xpr_data->numerrs++;
xpru.xpru_updatemask |= XPRU_ERRORS;
xpru.xpru_errors = IO->xpr_data->numerrs;
} else if (error == DT_TIME) {
IO->xpr_data->numtime++;
xpru.xpru_updatemask |= XPRU_TIMEOUTS;
xpru.xpru_timeouts = IO->xpr_data->numtime;
} else {
xpru.xpru_updatemask |= XPRU_BLOCKS | XPRU_BLOCKSIZE |
XPRU_BLOCKCHECK | XPRU_BYTES;
xpru.xpru_blocks = (long) Iblknum;
xpru.xpru_blocksize = (long) blksiz;
xpru.xpru_bytes = (long) blksiz *(long) Iblknum;
xpru.xpru_blockcheck = IO->xpr_data->crcmode ? blkchk[1] : blkchk[0];
}
/*
* Do the actual update
*/
if ((xupdate = IO->xpr_update) != NULL)
calla(xupdate, &xpru);
return;
}
/* mdsnd - send a buffer of data */
static int mdsnd(struct XPR_IO * IO)
{
int plength, retries, ch;
/* setup the packet header */
IO->xpr_data->packet[0] = IO->xpr_data->msgstart;
IO->xpr_data->packet[1] = IO->xpr_data->blknum;
IO->xpr_data->packet[2] = ~IO->xpr_data->blknum;
/* compute the block check code */
if (IO->xpr_data->crcmode) { /* compute the CRC */
long dumb_index;/* workaround manx expression too complex bug */
IO->xpr_data->chksum = (int)crc_compute(IO->xpr_data->buffer, IO->xpr_data->msglength);
IO->xpr_data->buffer[IO->xpr_data->msglength] = IO->xpr_data->chksum >> 8;
dumb_index = IO->xpr_data->msglength + 1;
IO->xpr_data->buffer[dumb_index] = IO->xpr_data->chksum;
plength = IO->xpr_data->msglength + 5;
} else { /* compute the checksum */
long dumb_index;/* workaround manx expression too complex bug */
IO->xpr_data->chksum = chk_compute(IO->xpr_data->buffer, IO->xpr_data->msglength);
dumb_index = IO->xpr_data->msglength;
IO->xpr_data->buffer[dumb_index] = IO->xpr_data->chksum;
plength = IO->xpr_data->msglength + 4;
}
/* send data and wait for an ACK */
for (retries = 0; retries < RETRY; retries++) {
/* send the data */
md_write(IO, (char *)IO->xpr_data->packet, plength);
/* return on an ACK */
if ((ch = md_get(IO, LTIME)) == ACK)
return (DT_OK);
/* abort transfer on two successive CAN's */
else if (ch == CAN) {
if ((ch = md_get(IO, STIME)) == ACK)
return (DT_OK);
else if (ch == CAN)
break;
} else if (ch == DT_ERR) {
dlabort(IO);
md_put(IO, CAN);
md_put(IO, CAN);
return (DT_ERR);
}
bm_info(IO, ch);
}
/* return failure */
return (DT_ERR);
}
/* msgput - put a message data character */
static int msgput(struct XPR_IO * IO, int ch)
{
int sts;
IO->xpr_data->buffer[IO->xpr_data->bufptr++] = ch;
if (IO->xpr_data->bufptr == IO->xpr_data->msglength) {
bm_info(IO, 0);
if ((sts = mdsnd(IO)) != DT_OK)
return (sts);
++IO->xpr_data->blknum;
IO->xpr_data->bufptr = 0;
}
return (ch);
}
/* mdrcv - receive a buffer of data */
static int mdrcv(struct XPR_IO * IO)
{
int plength, i, ch, retries;
/* receive data */
for (retries = 0; retries < RETRY + 1; retries++) {
/* check for data packet or eot */
if ((ch = md_get(IO, LTIME)) == DT_TIME) {
bm_info(IO, ch);
md_put(IO, IO->xpr_data->nak);
continue;
} else if (ch == DT_ERR) {
bm_info(IO, ch);
dlabort(IO);
md_put(IO, CAN);
md_put(IO, CAN);
return (DT_ERR);
} else if (ch == EOT) { /* end of transfer */
md_put(IO, ACK);
return (DT_EOF);
} else if (ch == SOH) /* start of a short packet */
IO->xpr_data->msglength = SMSGLEN;
else if (ch == STX) /* start of a long packet */
IO->xpr_data->msglength = LMSGLEN;
else {
bm_info(IO, DT_ERR);
dlabort(IO);
md_put(IO, IO->xpr_data->nak);
continue;
}
/* reset the NAK character */
IO->xpr_data->nak = NAK;
/* compute the packet length */
plength = IO->xpr_data->msglength + (IO->xpr_data->crcmode ? 5 : 4);
/* receive the data */
for (i = 1; i < plength; IO->xpr_data->packet[i++] = ch) {
if ((ch = md_get(IO, STIME)) == DT_TIME)
break;
else if (ch == DT_ERR)
break;
}
/* check for timeout */
if (ch == DT_TIME) {
bm_info(IO, ch);
md_put(IO, NAK);
continue;
}
if (ch == DT_ERR) {
bm_info(IO, ch);
dlabort(IO);
md_put(IO, CAN);
md_put(IO, CAN);
return (DT_ERR);
}
/* check the block number */
if (IO->xpr_data->packet[1] != (~IO->xpr_data->packet[2] & 0xFF)) {
bm_info(IO, DT_ERR);
md_put(IO, NAK);
continue;
}
/* check the block check code */
if (IO->xpr_data->crcmode) { /* CRC */
IO->xpr_data->chksum = (IO->xpr_data->buffer[IO->xpr_data->msglength] << 8) | IO->xpr_data->buffer[IO->xpr_data->msglength + 1];
if (IO->xpr_data->chksum != (int)crc_compute(IO->xpr_data->buffer, IO->xpr_data->msglength)) {
bm_info(IO, DT_ERR);
md_put(IO, NAK);
continue;
}
} else { /* checksum */
IO->xpr_data->chksum = IO->xpr_data->buffer[IO->xpr_data->msglength];
if (IO->xpr_data->chksum != chk_compute(IO->xpr_data->buffer, IO->xpr_data->msglength)) {
bm_info(IO, DT_ERR);
md_put(IO, NAK);
continue;
}
}
/* check the block number */
if (IO->xpr_data->packet[1] == (IO->xpr_data->blknum & 0xFF)) {
md_put(IO, ACK);
return (DT_OK);
} else if (IO->xpr_data->packet[1] != ((IO->xpr_data->blknum - 1) & 0xFF)) {
bm_info(IO, DT_ERR);
dlabort(IO);
md_put(IO, CAN);
md_put(IO, CAN);
return (DT_ERR);
}
/* send a ack */
md_put(IO, ACK);
}
/* return failure */
return (DT_ERR);
}
/* msgget - get a message data character */
static int msgget(struct XPR_IO * IO)
{
int sts;
if (IO->xpr_data->bufptr == IO->xpr_data->msglength) {
if ((sts = mdrcv(IO)) != DT_OK)
return (sts);
bm_info(IO, 0);
++IO->xpr_data->blknum;
IO->xpr_data->bufptr = 0;
}
return (IO->xpr_data->buffer[IO->xpr_data->bufptr++]);
}
/* dl_snd - send data across the link */
int dl_snd(struct XPR_IO * IO, int (*getch) (struct XPR_IO * IO))
{
int ch, retries;
IO->xpr_data->abort = 0;
/* setup message length */
if (IO->xpr_data->big) {
IO->xpr_data->msgstart = STX;
IO->xpr_data->msglength = LMSGLEN;
} else {
IO->xpr_data->msgstart = SOH;
IO->xpr_data->msglength = SMSGLEN;
}
/* initialize */
IO->xpr_data->blknum = 1; /* start a block number 1 */
IO->xpr_data->bufptr = 0; /* start with an empty buffer */
/* wait for the initial NAK (or CRC) */
for (retries = 0; retries < RETRY; retries++)
if ((ch = md_get(IO, XTIME)) == NAK) { /* start of checksum
* transfer */
IO->xpr_data->crcmode = FALSE;
break;
} else if (IO->xpr_data->crc_conf && ch == CRC) { /* start of CRC transfer */
IO->xpr_data->crcmode = TRUE;
break;
} else if (ch == DT_ERR) {
bm_info(IO, DT_ERR);
dlabort(IO);
return (FALSE);
} else if (ch == DT_TIME) {
bm_info(IO, DT_TIME);
dlabort(IO);
return (FALSE);
} else
dlabort(IO);
/* check for failure */
if (retries >= RETRY)
return (FALSE);
/* send each byte */
while ((ch = (*getch) (IO)) != EOF)
if (msgput(IO, ch) == DT_ERR)
return (FALSE);
/* flush partial buffer */
if (IO->xpr_data->bufptr > 0)
while (IO->xpr_data->bufptr > 0)
if (msgput(IO, 0) == DT_ERR)
return (FALSE);
/* send EOT and wait for ACK */
for (retries = 0; retries < RETRY; retries++) {
md_put(IO, EOT);
if (md_get(IO, LTIME) == ACK)
return (TRUE);
}
/* return failure */
return (FALSE);
}
/* dl_rcv - receive data across the link */
int dl_rcv(struct XPR_IO * IO, void (*putch) (struct XPR_IO * IO, int ch))
{
int ch;
/* initialize */
IO->xpr_data->abort = 0;
IO->xpr_data->blknum = 1;
IO->xpr_data->bufptr = IO->xpr_data->msglength = SMSGLEN;
/* send the initial NAK (or CRC) */
IO->xpr_data->nak = (IO->xpr_data->crc_conf ? CRC : NAK);
IO->xpr_data->crcmode = IO->xpr_data->crc_conf;
md_put(IO, IO->xpr_data->nak);
/* receive each byte */
while ((ch = msgget(IO)) != DT_EOF && ch != DT_ERR)
(*putch) (IO, ch);
/* return with status */
return (ch == DT_EOF);
}
void bm_infoinit(struct XPR_IO * IO, int send, long size)
{
long (*xupdate) ();
struct XPR_UPDATE xpru;
char buff[20];
IO->xpr_data->numerrs = 0L;
IO->xpr_data->numtime = 0L;
if (send)
strcpy(buff, "Send ");
else
strcpy(buff, "Receive ");
if (IO->xpr_data->ascii)
strcat(buff, "Text ");
else
strcat(buff, "Binary");
xpru.xpru_updatemask = XPRU_MSG | XPRU_FILENAME |
XPRU_BLOCKSIZE | XPRU_BLOCKCHECK | XPRU_BYTES |
XPRU_BLOCKS | XPRU_TIMEOUTS | XPRU_ERRORS;
IO->xpr_data->filsiz = size;
if (size)
xpru.xpru_updatemask |= XPRU_FILESIZE;
xpru.xpru_filename = IO->xpr_filename;
xpru.xpru_filesize = size;
xpru.xpru_msg = buff;
xpru.xpru_blocks = 0L;
xpru.xpru_errors = 0L;
xpru.xpru_timeouts = 0L;
xpru.xpru_blocksize = IO->xpr_data->big ? 1024L : 128L;
xpru.xpru_blockcheck = IO->xpr_data->crc_conf ? blkchk[1] : blkchk[0];
xpru.xpru_bytes = 0L;
if ((xupdate = IO->xpr_update) != NULL)
calla(xupdate, &xpru);
CurrentTime(&IO->xpr_data->startsecs, &IO->xpr_data->startmics);
return;
}