7551d83c35
Mainly focus on files that use BSD 2-Clause license, however the tool I was using misidentified many licenses so this was mostly a manual - error prone - task. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts. No functional change intended.
348 lines
8.8 KiB
C
348 lines
8.8 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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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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* $FreeBSD$
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*/
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#include <sys/types.h>
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#include <stdlib.h>
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#include <string.h>
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#include <termios.h>
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#include "defs.h"
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#include "layer.h"
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#include "mbuf.h"
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#include "log.h"
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#include "timer.h"
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#include "fsm.h"
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#include "lqr.h"
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#include "hdlc.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 HASH(state, x) state->hash = (state->hash << 4) ^ (x)
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#define GUESS_TABLE_SIZE 65536
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struct pred1_state {
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u_short hash;
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u_char dict[GUESS_TABLE_SIZE];
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};
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static int
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compress(struct pred1_state *state, 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 (state->dict[state->hash] == *source) {
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flags |= bitmask; /* Guess was right - don't output */
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} else {
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state->dict[state->hash] = *source;
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*dest++ = *source; /* Guess wrong, output char */
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}
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HASH(state, *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(struct pred1_state *state, u_char *source, u_char *dest, int len)
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{
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while (len--) {
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*dest++ = state->dict[state->hash] = *source;
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HASH(state, *source++);
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}
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}
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static int
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decompress(struct pred1_state *state, 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 = state->dict[state->hash]; /* 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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state->dict[state->hash] = *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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HASH(state, *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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Pred1Term(void *v)
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{
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struct pred1_state *state = (struct pred1_state *)v;
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free(state);
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}
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static void
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Pred1ResetInput(void *v)
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{
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struct pred1_state *state = (struct pred1_state *)v;
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state->hash = 0;
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memset(state->dict, '\0', sizeof state->dict);
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log_Printf(LogCCP, "Predictor1: Input channel reset\n");
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}
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static int
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Pred1ResetOutput(void *v)
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{
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struct pred1_state *state = (struct pred1_state *)v;
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state->hash = 0;
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memset(state->dict, '\0', sizeof state->dict);
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log_Printf(LogCCP, "Predictor1: Output channel reset\n");
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return 1; /* Ask FSM to ACK */
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}
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static void *
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Pred1InitInput(struct bundle *bundle __unused, struct fsm_opt *o __unused)
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{
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struct pred1_state *state;
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state = (struct pred1_state *)malloc(sizeof(struct pred1_state));
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if (state != NULL)
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Pred1ResetInput(state);
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return state;
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}
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static void *
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Pred1InitOutput(struct bundle *bundle __unused, struct fsm_opt *o __unused)
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{
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struct pred1_state *state;
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state = (struct pred1_state *)malloc(sizeof(struct pred1_state));
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if (state != NULL)
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Pred1ResetOutput(state);
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return state;
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}
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static struct mbuf *
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Pred1Output(void *v, struct ccp *ccp, struct link *l __unused,
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int pri __unused, u_short *proto, struct mbuf *bp)
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{
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struct pred1_state *state = (struct pred1_state *)v;
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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 = m_length(bp) + 2; /* add count of proto */
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mwp = m_get((orglen + 2) / 8 * 9 + 12, MB_CCPOUT);
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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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mbuf_Read(bp, cp, orglen - 2);
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fcs = hdlc_Fcs(bufp, 2 + orglen);
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fcs = ~fcs;
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len = compress(state, bufp + 2, wp, orglen);
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log_Printf(LogDEBUG, "Pred1Output: orglen (%d) --> len (%d)\n", orglen, len);
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ccp->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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ccp->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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ccp->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->m_len = wp - MBUF_CTOP(mwp);
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*proto = ccp_Proto(ccp);
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return mwp;
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}
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static struct mbuf *
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Pred1Input(void *v, struct ccp *ccp, u_short *proto, struct mbuf *bp)
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{
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struct pred1_state *state = (struct pred1_state *)v;
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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 = m_get(MAX_MRU + 2, MB_CCPIN);
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cp = MBUF_CTOP(bp);
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olen = m_length(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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ccp->uncompin += len & 0x7fff;
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if (len & 0x8000) {
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len1 = decompress(state, cp, pp, olen - 4);
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ccp->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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log_Printf(LogCCP, "Pred1: Length error (got %d, not %d)\n", len1, len);
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fsm_Reopen(&ccp->fsm);
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m_freem(bp);
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m_freem(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 if (len + 4 != olen) {
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log_Printf(LogCCP, "Pred1: Length error (got %d, not %d)\n", len + 4, olen);
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fsm_Reopen(&ccp->fsm);
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m_freem(wp);
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m_freem(bp);
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return NULL;
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} else {
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ccp->compin += len;
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SyncTable(state, 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 = hdlc_Fcs(bufp, wp->m_len = pp - bufp);
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if (fcs == GOODFCS) {
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wp->m_offset += 2; /* skip length */
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wp->m_len -= 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->m_offset++;
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wp->m_len--;
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} else {
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wp->m_offset += 2;
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wp->m_len -= 2;
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*proto = (*proto << 8) | *pp++;
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}
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m_freem(bp);
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return wp;
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} else {
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const char *pre = *MBUF_CTOP(bp) & 0x80 ? "" : "un";
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log_Printf(LogDEBUG, "Pred1Input: fcs = 0x%04x (%scompressed), len = 0x%x,"
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" olen = 0x%x\n", fcs, pre, len, olen);
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log_Printf(LogCCP, "%s: Bad %scompressed CRC-16\n",
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ccp->fsm.link->name, pre);
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fsm_Reopen(&ccp->fsm);
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m_freem(wp);
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}
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m_freem(bp);
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return NULL;
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}
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static void
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Pred1DictSetup(void *v __unused, struct ccp *ccp __unused,
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u_short proto __unused, struct mbuf *bp __unused)
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{
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/* Nothing to see here */
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}
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static const char *
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Pred1DispOpts(struct fsm_opt *o __unused)
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{
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return NULL;
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}
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static void
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Pred1InitOptsOutput(struct bundle *bundle __unused, struct fsm_opt *o,
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const struct ccp_config *cfg __unused)
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{
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o->hdr.len = 2;
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}
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static int
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Pred1SetOpts(struct bundle *bundle __unused, struct fsm_opt *o,
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const struct ccp_config *cfg __unused)
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{
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if (o->hdr.len != 2) {
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o->hdr.len = 2;
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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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CCP_NEG_PRED1,
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Pred1DispOpts,
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ccp_DefaultUsable,
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ccp_DefaultRequired,
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{
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Pred1SetOpts,
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Pred1InitInput,
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Pred1Term,
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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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0,
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Pred1InitOptsOutput,
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Pred1SetOpts,
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Pred1InitOutput,
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Pred1Term,
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Pred1ResetOutput,
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Pred1Output
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},
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};
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