1995-01-31 06:29:58 +00:00
|
|
|
#include "fsm.h"
|
|
|
|
#include "hdlc.h"
|
|
|
|
#include "lcpproto.h"
|
|
|
|
#include "ccp.h"
|
|
|
|
|
|
|
|
/*
|
1995-05-30 03:57:47 +00:00
|
|
|
*
|
1997-06-09 23:38:38 +00:00
|
|
|
* $Id: pred.c,v 1.12 1997/06/09 03:27:35 brian Exp $
|
1995-05-30 03:57:47 +00:00
|
|
|
*
|
1995-01-31 06:29:58 +00:00
|
|
|
* pred.c -- Test program for Dave Rand's rendition of the
|
|
|
|
* predictor algorithm
|
|
|
|
* Updated by: iand@labtam.labtam.oz.au (Ian Donaldson)
|
|
|
|
* Updated by: Carsten Bormann <cabo@cs.tu-berlin.de>
|
|
|
|
* Original : Dave Rand <dlr@bungi.com>/<dave_rand@novell.com>
|
|
|
|
*/
|
|
|
|
|
|
|
|
/* The following hash code is the heart of the algorithm:
|
|
|
|
* It builds a sliding hash sum of the previous 3-and-a-bit characters
|
|
|
|
* which will be used to index the guess table.
|
|
|
|
* A better hash function would result in additional compression,
|
|
|
|
* at the expense of time.
|
|
|
|
*/
|
1997-05-10 01:22:19 +00:00
|
|
|
#define IHASH(x) do {iHash = (iHash << 4) ^ (x);} while(0)
|
|
|
|
#define OHASH(x) do {oHash = (oHash << 4) ^ (x);} while(0)
|
1995-01-31 06:29:58 +00:00
|
|
|
|
|
|
|
static unsigned short int iHash, oHash;
|
|
|
|
static unsigned char InputGuessTable[65536];
|
|
|
|
static unsigned char OutputGuessTable[65536];
|
|
|
|
|
|
|
|
static int
|
|
|
|
compress(source, dest, len)
|
|
|
|
unsigned char *source, *dest;
|
|
|
|
int len;
|
|
|
|
{
|
|
|
|
int i, bitmask;
|
|
|
|
unsigned char *flagdest, flags, *orgdest;
|
|
|
|
|
|
|
|
orgdest = dest;
|
|
|
|
while (len) {
|
|
|
|
flagdest = dest++; flags = 0; /* All guess wrong initially */
|
|
|
|
for (bitmask=1, i=0; i < 8 && len; i++, bitmask <<= 1) {
|
|
|
|
if (OutputGuessTable[oHash] == *source) {
|
|
|
|
flags |= bitmask; /* Guess was right - don't output */
|
|
|
|
} else {
|
|
|
|
OutputGuessTable[oHash] = *source;
|
|
|
|
*dest++ = *source; /* Guess wrong, output char */
|
|
|
|
}
|
|
|
|
OHASH(*source++);len--;
|
|
|
|
}
|
|
|
|
*flagdest = flags;
|
|
|
|
}
|
|
|
|
return(dest - orgdest);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void
|
|
|
|
SyncTable(source, dest, len)
|
|
|
|
unsigned char *source, *dest;
|
|
|
|
int len;
|
|
|
|
{
|
|
|
|
|
|
|
|
while (len--) {
|
|
|
|
if (InputGuessTable[iHash] != *source) {
|
|
|
|
InputGuessTable[iHash] = *source;
|
|
|
|
}
|
|
|
|
IHASH(*dest++ = *source++);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
static int
|
|
|
|
decompress(source, dest, len)
|
|
|
|
unsigned char *source, *dest;
|
|
|
|
int len;
|
|
|
|
{
|
|
|
|
int i, bitmask;
|
|
|
|
unsigned char flags, *orgdest;
|
|
|
|
|
|
|
|
orgdest = dest;
|
|
|
|
while (len) {
|
|
|
|
flags = *source++;
|
|
|
|
len--;
|
|
|
|
for (i=0, bitmask = 1; i < 8; i++, bitmask <<= 1) {
|
|
|
|
if (flags & bitmask) {
|
|
|
|
*dest = InputGuessTable[iHash]; /* Guess correct */
|
|
|
|
} else {
|
|
|
|
if (!len)
|
|
|
|
break; /* we seem to be really done -- cabo */
|
|
|
|
InputGuessTable[iHash] = *source; /* Guess wrong */
|
|
|
|
*dest = *source++; /* Read from source */
|
|
|
|
len--;
|
|
|
|
}
|
|
|
|
IHASH(*dest++);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
return(dest - orgdest);
|
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
Pred1Init(direction)
|
|
|
|
int direction;
|
|
|
|
{
|
|
|
|
if (direction & 1) { /* Input part */
|
|
|
|
iHash = 0;
|
|
|
|
bzero(InputGuessTable, sizeof(InputGuessTable));
|
|
|
|
}
|
|
|
|
if (direction & 2) { /* Output part */
|
|
|
|
oHash = 0;
|
|
|
|
bzero(OutputGuessTable, sizeof(OutputGuessTable));
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
void
|
1997-05-10 01:22:19 +00:00
|
|
|
Pred1Output(int pri, u_short proto, struct mbuf *bp)
|
1995-01-31 06:29:58 +00:00
|
|
|
{
|
|
|
|
struct mbuf *mwp;
|
|
|
|
u_char *cp, *wp, *hp;
|
|
|
|
int orglen, len;
|
1997-06-09 23:38:38 +00:00
|
|
|
u_char bufp[MAX_MTU+2];
|
1995-01-31 06:29:58 +00:00
|
|
|
u_short fcs;
|
|
|
|
|
|
|
|
orglen = plength(bp) + 2; /* add count of proto */
|
|
|
|
mwp = mballoc((orglen+2)/8*9+12, MB_HDLCOUT);
|
|
|
|
hp = wp = MBUF_CTOP(mwp);
|
|
|
|
cp = bufp;
|
|
|
|
*wp++ = *cp++ = orglen >> 8;
|
|
|
|
*wp++ = *cp++ = orglen & 0377;
|
|
|
|
*cp++ = proto >> 8;
|
|
|
|
*cp++ = proto & 0377;
|
|
|
|
mbread(bp, cp, orglen-2);
|
|
|
|
fcs = HdlcFcs(INITFCS, bufp, 2+orglen);
|
|
|
|
fcs = ~fcs;
|
|
|
|
|
|
|
|
len = compress(bufp + 2, wp, orglen);
|
1997-06-09 03:27:43 +00:00
|
|
|
LogPrintf(LogDEBUG, "Pred1Output: orglen (%d) --> len (%d)\n", orglen, len);
|
1995-01-31 06:29:58 +00:00
|
|
|
CcpInfo.orgout += orglen;
|
|
|
|
if (len < orglen) {
|
|
|
|
*hp |= 0x80;
|
|
|
|
wp += len;
|
|
|
|
CcpInfo.compout += len;
|
|
|
|
} else {
|
|
|
|
bcopy(bufp+2, wp, orglen);
|
|
|
|
wp += orglen;
|
|
|
|
CcpInfo.compout += orglen;
|
|
|
|
}
|
|
|
|
|
|
|
|
*wp++ = fcs & 0377;
|
|
|
|
*wp++ = fcs >> 8;
|
|
|
|
mwp->cnt = wp - MBUF_CTOP(mwp);
|
1996-01-30 11:08:50 +00:00
|
|
|
HdlcOutput(PRI_NORMAL, PROTO_COMPD, mwp);
|
1995-01-31 06:29:58 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
Pred1Input(bp)
|
|
|
|
struct mbuf *bp;
|
|
|
|
{
|
|
|
|
u_char *cp, *pp;
|
|
|
|
int len, olen, len1;
|
|
|
|
struct mbuf *wp;
|
|
|
|
u_char *bufp;
|
|
|
|
u_short fcs, proto;
|
|
|
|
|
1997-06-09 23:38:38 +00:00
|
|
|
wp = mballoc(MAX_MTU+2, MB_IPIN);
|
1995-01-31 06:29:58 +00:00
|
|
|
cp = MBUF_CTOP(bp);
|
|
|
|
olen = plength(bp);
|
|
|
|
pp = bufp = MBUF_CTOP(wp);
|
|
|
|
*pp++ = *cp & 0177;
|
|
|
|
len = *cp++ << 8;
|
|
|
|
*pp++ = *cp;
|
|
|
|
len += *cp++;
|
|
|
|
CcpInfo.orgin += len & 0x7fff;
|
|
|
|
if (len & 0x8000) {
|
|
|
|
len1 = decompress(cp, pp, olen - 4);
|
|
|
|
CcpInfo.compin += olen;
|
|
|
|
len &= 0x7fff;
|
|
|
|
if (len != len1) { /* Error is detected. Send reset request */
|
1997-06-09 03:27:43 +00:00
|
|
|
LogPrintf(LogLCP, "%s: Length Error\n", CcpFsm.name);
|
1995-01-31 06:29:58 +00:00
|
|
|
CcpSendResetReq(&CcpFsm);
|
|
|
|
pfree(bp);
|
1996-01-30 11:08:50 +00:00
|
|
|
pfree(wp);
|
1995-01-31 06:29:58 +00:00
|
|
|
return;
|
|
|
|
}
|
|
|
|
cp += olen - 4;
|
|
|
|
pp += len1;
|
|
|
|
} else {
|
|
|
|
CcpInfo.compin += len;
|
|
|
|
SyncTable(cp, pp, len);
|
|
|
|
cp += len;
|
|
|
|
pp += len;
|
|
|
|
}
|
|
|
|
*pp++ = *cp++; /* CRC */
|
|
|
|
*pp++ = *cp++;
|
|
|
|
fcs = HdlcFcs(INITFCS, bufp, wp->cnt = pp - bufp);
|
1996-01-30 11:08:50 +00:00
|
|
|
if (fcs != GOODFCS)
|
1997-06-09 03:27:43 +00:00
|
|
|
LogPrintf(LogDEBUG, "Pred1Input: fcs = 0x%04x (%s), len = 0x%x,"
|
|
|
|
" olen = 0x%x\n", fcs, (fcs == GOODFCS)? "good" : "bad",
|
|
|
|
len, olen);
|
1995-01-31 06:29:58 +00:00
|
|
|
if (fcs == GOODFCS) {
|
|
|
|
wp->offset += 2; /* skip length */
|
|
|
|
wp->cnt -= 4; /* skip length & CRC */
|
|
|
|
pp = MBUF_CTOP(wp);
|
|
|
|
proto = *pp++;
|
|
|
|
if (proto & 1) {
|
|
|
|
wp->offset++;
|
|
|
|
wp->cnt--;
|
|
|
|
} else {
|
|
|
|
wp->offset += 2;
|
|
|
|
wp->cnt -= 2;
|
|
|
|
proto = (proto << 8) | *pp++;
|
|
|
|
}
|
|
|
|
DecodePacket(proto, wp);
|
|
|
|
}
|
1996-01-30 11:08:50 +00:00
|
|
|
else
|
|
|
|
{
|
1997-06-09 03:27:43 +00:00
|
|
|
LogDumpBp(LogHDLC, "Bad FCS", wp);
|
1996-07-21 13:01:27 +00:00
|
|
|
CcpSendResetReq(&CcpFsm);
|
1996-01-30 11:08:50 +00:00
|
|
|
pfree(wp);
|
|
|
|
}
|
1995-01-31 06:29:58 +00:00
|
|
|
pfree(bp);
|
|
|
|
}
|