7308ec6890
IPCP, CCP and LCP are now just derived FSMs. Comment each of the FSM implementations so that we can tell what's going on. Revise the state transitions so that CCP and IPCP actually send terminate REQs when appropriate. The OS & IPCP layers are still like spagetti (next job).
345 lines
8.1 KiB
C
345 lines
8.1 KiB
C
/*-
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* Copyright (c) 1997 Brian Somers <brian@Awfulhak.org>
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* Ian Donaldson <iand@labtam.labtam.oz.au>
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* Carsten Bormann <cabo@cs.tu-berlin.de>
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* Dave Rand <dlr@bungi.com>/<dave_rand@novell.com>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: pred.c,v 1.20.2.2 1998/01/30 19:46:04 brian Exp $
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*/
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#include <sys/param.h>
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#include <netinet/in.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "command.h"
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#include "mbuf.h"
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#include "log.h"
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#include "defs.h"
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#include "loadalias.h"
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#include "vars.h"
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#include "timer.h"
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#include "fsm.h"
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#include "hdlc.h"
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#include "lcpproto.h"
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#include "lcp.h"
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#include "ccp.h"
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#include "throughput.h"
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#include "link.h"
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#include "pred.h"
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/* The following hash code is the heart of the algorithm:
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* It builds a sliding hash sum of the previous 3-and-a-bit characters
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* which will be used to index the guess table.
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* A better hash function would result in additional compression,
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* at the expense of time.
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*/
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#define IHASH(x) do {iHash = (iHash << 4) ^ (x);} while(0)
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#define OHASH(x) do {oHash = (oHash << 4) ^ (x);} while(0)
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#define GUESS_TABLE_SIZE 65536
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static unsigned short int iHash, oHash;
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static unsigned char *InputGuessTable;
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static unsigned char *OutputGuessTable;
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static int
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compress(u_char * source, u_char * dest, int len)
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{
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int i, bitmask;
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unsigned char *flagdest, flags, *orgdest;
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orgdest = dest;
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while (len) {
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flagdest = dest++;
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flags = 0; /* All guess wrong initially */
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for (bitmask = 1, i = 0; i < 8 && len; i++, bitmask <<= 1) {
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if (OutputGuessTable[oHash] == *source) {
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flags |= bitmask; /* Guess was right - don't output */
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} else {
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OutputGuessTable[oHash] = *source;
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*dest++ = *source; /* Guess wrong, output char */
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}
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OHASH(*source++);
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len--;
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}
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*flagdest = flags;
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}
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return (dest - orgdest);
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}
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static void
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SyncTable(u_char * source, u_char * dest, int len)
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{
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while (len--) {
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if (InputGuessTable[iHash] != *source) {
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InputGuessTable[iHash] = *source;
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}
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IHASH(*dest++ = *source++);
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}
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}
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static int
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decompress(u_char * source, u_char * dest, int len)
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{
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int i, bitmask;
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unsigned char flags, *orgdest;
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orgdest = dest;
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while (len) {
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flags = *source++;
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len--;
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for (i = 0, bitmask = 1; i < 8; i++, bitmask <<= 1) {
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if (flags & bitmask) {
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*dest = InputGuessTable[iHash]; /* Guess correct */
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} else {
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if (!len)
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break; /* we seem to be really done -- cabo */
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InputGuessTable[iHash] = *source; /* Guess wrong */
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*dest = *source++; /* Read from source */
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len--;
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}
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IHASH(*dest++);
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}
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}
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return (dest - orgdest);
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}
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static void
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Pred1TermInput(void)
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{
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if (InputGuessTable != NULL) {
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free(InputGuessTable);
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InputGuessTable = NULL;
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}
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}
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static void
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Pred1TermOutput(void)
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{
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if (OutputGuessTable != NULL) {
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free(OutputGuessTable);
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OutputGuessTable = NULL;
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}
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}
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static void
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Pred1ResetInput(void)
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{
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iHash = 0;
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memset(InputGuessTable, '\0', GUESS_TABLE_SIZE);
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LogPrintf(LogCCP, "Predictor1: Input channel reset\n");
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}
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static void
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Pred1ResetOutput(void)
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{
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oHash = 0;
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memset(OutputGuessTable, '\0', GUESS_TABLE_SIZE);
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LogPrintf(LogCCP, "Predictor1: Output channel reset\n");
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}
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static int
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Pred1InitInput(void)
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{
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if (InputGuessTable == NULL)
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if ((InputGuessTable = malloc(GUESS_TABLE_SIZE)) == NULL)
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return 0;
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Pred1ResetInput();
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return 1;
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}
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static int
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Pred1InitOutput(void)
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{
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if (OutputGuessTable == NULL)
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if ((OutputGuessTable = malloc(GUESS_TABLE_SIZE)) == NULL)
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return 0;
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Pred1ResetOutput();
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return 1;
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}
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static int
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Pred1Output(struct link *l, int pri, u_short proto, struct mbuf * bp)
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{
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struct mbuf *mwp;
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u_char *cp, *wp, *hp;
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int orglen, len;
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u_char bufp[MAX_MTU + 2];
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u_short fcs;
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orglen = plength(bp) + 2; /* add count of proto */
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mwp = mballoc((orglen + 2) / 8 * 9 + 12, MB_HDLCOUT);
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hp = wp = MBUF_CTOP(mwp);
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cp = bufp;
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*wp++ = *cp++ = orglen >> 8;
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*wp++ = *cp++ = orglen & 0377;
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*cp++ = proto >> 8;
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*cp++ = proto & 0377;
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mbread(bp, cp, orglen - 2);
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fcs = HdlcFcs(INITFCS, bufp, 2 + orglen);
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fcs = ~fcs;
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len = compress(bufp + 2, wp, orglen);
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LogPrintf(LogDEBUG, "Pred1Output: orglen (%d) --> len (%d)\n", orglen, len);
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CcpInfo.uncompout += orglen;
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if (len < orglen) {
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*hp |= 0x80;
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wp += len;
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CcpInfo.compout += len;
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} else {
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memcpy(wp, bufp + 2, orglen);
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wp += orglen;
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CcpInfo.compout += orglen;
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}
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*wp++ = fcs & 0377;
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*wp++ = fcs >> 8;
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mwp->cnt = wp - MBUF_CTOP(mwp);
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HdlcOutput(l, PRI_NORMAL, PROTO_COMPD, mwp);
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return 1;
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}
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static struct mbuf *
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Pred1Input(u_short *proto, struct mbuf *bp)
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{
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u_char *cp, *pp;
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int len, olen, len1;
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struct mbuf *wp;
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u_char *bufp;
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u_short fcs;
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wp = mballoc(MAX_MTU + 2, MB_IPIN);
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cp = MBUF_CTOP(bp);
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olen = plength(bp);
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pp = bufp = MBUF_CTOP(wp);
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*pp++ = *cp & 0177;
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len = *cp++ << 8;
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*pp++ = *cp;
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len += *cp++;
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CcpInfo.uncompin += len & 0x7fff;
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if (len & 0x8000) {
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len1 = decompress(cp, pp, olen - 4);
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CcpInfo.compin += olen;
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len &= 0x7fff;
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if (len != len1) { /* Error is detected. Send reset request */
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LogPrintf(LogCCP, "Pred1: Length error\n");
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CcpSendResetReq(&CcpInfo.fsm);
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pfree(bp);
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pfree(wp);
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return NULL;
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}
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cp += olen - 4;
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pp += len1;
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} else {
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CcpInfo.compin += len;
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SyncTable(cp, pp, len);
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cp += len;
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pp += len;
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}
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*pp++ = *cp++; /* CRC */
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*pp++ = *cp++;
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fcs = HdlcFcs(INITFCS, bufp, wp->cnt = pp - bufp);
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if (fcs != GOODFCS)
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LogPrintf(LogDEBUG, "Pred1Input: fcs = 0x%04x (%s), len = 0x%x,"
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" olen = 0x%x\n", fcs, (fcs == GOODFCS) ? "good" : "bad",
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len, olen);
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if (fcs == GOODFCS) {
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wp->offset += 2; /* skip length */
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wp->cnt -= 4; /* skip length & CRC */
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pp = MBUF_CTOP(wp);
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*proto = *pp++;
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if (*proto & 1) {
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wp->offset++;
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wp->cnt--;
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} else {
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wp->offset += 2;
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wp->cnt -= 2;
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*proto = (*proto << 8) | *pp++;
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}
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pfree(bp);
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return wp;
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} else {
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LogDumpBp(LogHDLC, "Bad FCS", wp);
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CcpSendResetReq(&CcpInfo.fsm);
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pfree(wp);
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}
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pfree(bp);
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return NULL;
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}
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static void
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Pred1DictSetup(u_short proto, struct mbuf * bp)
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{
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}
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static const char *
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Pred1DispOpts(struct lcp_opt *o)
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{
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return NULL;
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}
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static void
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Pred1GetOpts(struct lcp_opt *o)
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{
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o->id = TY_PRED1;
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o->len = 2;
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}
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static int
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Pred1SetOpts(struct lcp_opt *o)
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{
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if (o->id != TY_PRED1 || o->len != 2) {
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Pred1GetOpts(o);
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return MODE_NAK;
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}
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return MODE_ACK;
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}
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const struct ccp_algorithm Pred1Algorithm = {
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TY_PRED1,
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ConfPred1,
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Pred1DispOpts,
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{
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Pred1GetOpts,
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Pred1SetOpts,
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Pred1InitInput,
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Pred1TermInput,
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Pred1ResetInput,
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Pred1Input,
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Pred1DictSetup
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},
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{
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Pred1GetOpts,
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Pred1SetOpts,
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Pred1InitOutput,
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Pred1TermOutput,
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Pred1ResetOutput,
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Pred1Output
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},
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};
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