Author: pfg
Date: Tue Jun 21 15:47:54 2016
New Revision: 302061
URL: https://svnweb.freebsd.org/changeset/base/302061
Log:
MFC r301549, r301550:
ng_mppc(4): Bring netgraph(3) MPPC compression support.
Support for compression has been available from July 2007 but it
was never imported due to concerns with patents once held by
STAC/HiFn. The issues have clearly been resolved so bring it
in now.
Special thanks to Brett Glass for preserving the code and
pointing documentation for the expiration case.
Taken from: mav (through Brett Glass)
Added:
stable/10/sys/net/mppc.h
- copied unchanged from r301549, head/sys/net/mppc.h
stable/10/sys/net/mppcc.c
- copied unchanged from r301549, head/sys/net/mppcc.c
stable/10/sys/net/mppcd.c
- copied unchanged from r301549, head/sys/net/mppcd.c
Modified:
stable/10/share/man/man4/ng_mppc.4
stable/10/sys/modules/netgraph/mppc/Makefile
Directory Properties:
stable/10/ (props changed)
Modified: stable/10/share/man/man4/ng_mppc.4
==============================================================================
--- stable/10/share/man/man4/ng_mppc.4 Tue Jun 21 15:38:20 2016
(r302060)
+++ stable/10/share/man/man4/ng_mppc.4 Tue Jun 21 15:47:54 2016
(r302061)
@@ -35,7 +35,7 @@
.\" $Whistle: ng_mppc.8,v 1.1 1999/12/08 20:20:39 archie Exp $
.\" $FreeBSD$
.\"
-.Dd December 8, 1999
+.Dd June 7, 2016
.Dt NG_MPPC 4
.Os
.Sh NAME
@@ -153,12 +153,6 @@ and
are supplied to selectively compile in either or both capabilities.
At least one of these must be defined, or else this node type is useless.
.Pp
-The MPPC protocol requires proprietary compression code available
-from Hi/Fn (formerly STAC).
-These files must be obtained elsewhere and added to the kernel
-sources before this node type will compile with the
-.Dv NETGRAPH_MPPC_COMPRESSION
-option.
.Sh SEE ALSO
.Xr netgraph 4 ,
.Xr ng_ppp 4 ,
Modified: stable/10/sys/modules/netgraph/mppc/Makefile
==============================================================================
--- stable/10/sys/modules/netgraph/mppc/Makefile Tue Jun 21 15:38:20
2016 (r302060)
+++ stable/10/sys/modules/netgraph/mppc/Makefile Tue Jun 21 15:47:54
2016 (r302061)
@@ -4,11 +4,10 @@
KMOD= ng_mppc
SRCS= ng_mppc.c opt_netgraph.h
-NETGRAPH_MPPC_COMPRESSION?= 0
+NETGRAPH_MPPC_COMPRESSION?= 1
NETGRAPH_MPPC_ENCRYPTION?= 1
.if ${NETGRAPH_MPPC_COMPRESSION} > 0
-# XXX These files don't exist yet, but hopefully someday they will...
.PATH: ${.CURDIR}/../../../net
SRCS+= mppcc.c mppcd.c
.endif
Copied: stable/10/sys/net/mppc.h (from r301549, head/sys/net/mppc.h)
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ stable/10/sys/net/mppc.h Tue Jun 21 15:47:54 2016 (r302061, copy
of r301549, head/sys/net/mppc.h)
@@ -0,0 +1,62 @@
+/*-
+ * Copyright (c) 2007 Alexander Motin <m...@freebsd.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice unmodified, this list of conditions, and the following
+ * disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * MPPC decompression library.
+ * Version 1.0
+ *
+ * Note that Hi/Fn (later acquired by Exar Corporation) held US patents
+ * on some implementation-critical aspects of MPPC compression.
+ * These patents lapsed due to non-payment of fees in 2007 and by 2015
+ * expired altogether.
+ */
+
+#ifndef _NET_MPPC_H_
+#define _NET_MPPC_H_
+
+#define MPPC_MANDATORY_COMPRESS_FLAGS 0
+#define MPPC_MANDATORY_DECOMPRESS_FLAGS 0
+
+#define MPPC_SAVE_HISTORY 1
+
+#define MPPC_OK 5
+#define MPPC_EXPANDED 8
+#define MPPC_RESTART_HISTORY 16
+#define MPPC_DEST_EXHAUSTED 32
+
+extern size_t MPPC_SizeOfCompressionHistory(void);
+extern size_t MPPC_SizeOfDecompressionHistory(void);
+
+extern void MPPC_InitCompressionHistory(char *history);
+extern void MPPC_InitDecompressionHistory(char *history);
+
+extern int MPPC_Compress(u_char **src, u_char **dst, u_long *srcCnt, u_long
*dstCnt, char *history, int flags, int undef);
+extern int MPPC_Decompress(u_char **src, u_char **dst, u_long *srcCnt, u_long
*dstCnt, char *history, int flags);
+
+#endif
Copied: stable/10/sys/net/mppcc.c (from r301549, head/sys/net/mppcc.c)
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ stable/10/sys/net/mppcc.c Tue Jun 21 15:47:54 2016 (r302061, copy
of r301549, head/sys/net/mppcc.c)
@@ -0,0 +1,299 @@
+/*-
+ * Copyright (c) 2002-2004 Jan Dubiec <j...@slackware.pl>
+ * Copyright (c) 2007 Alexander Motin <m...@freebsd.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice unmodified, this list of conditions, and the following
+ * disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * MPPC decompression library.
+ * Version 1.0
+ *
+ * Note that Hi/Fn (later acquired by Exar Corporation) held US patents
+ * on some implementation-critical aspects of MPPC compression.
+ * These patents lapsed due to non-payment of fees in 2007 and by 2015
+ * expired altogether.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+
+#include <net/mppc.h>
+
+#define MPPE_HIST_LEN 8192
+
+#define HASH(x)
(((40543*(((((x)[0]<<4)^(x)[1])<<4)^(x)[2]))>>4) & 0x1fff)
+
+struct MPPC_comp_state {
+ uint8_t hist[2*MPPE_HIST_LEN];
+ uint16_t histptr;
+ uint16_t hash[MPPE_HIST_LEN];
+};
+
+/* Inserts 1 to 8 bits into the output buffer. */
+static void __inline
+putbits8(uint8_t *buf, uint32_t val, const uint32_t n, uint32_t *i, uint32_t
*l)
+{
+ buf += *i;
+ if (*l >= n) {
+ *l = (*l) - n;
+ val <<= *l;
+ *buf = *buf | (val & 0xff);
+ if (*l == 0) {
+ *l = 8;
+ (*i)++;
+ *(++buf) = 0;
+ }
+ } else {
+ (*i)++;
+ *l = 8 - n + (*l);
+ val <<= *l;
+ *buf = *buf | ((val >> 8) & 0xff);
+ *(++buf) = val & 0xff;
+ }
+}
+
+/* Inserts 9 to 16 bits into the output buffer. */
+static void __inline
+putbits16(uint8_t *buf, uint32_t val, const uint32_t n, uint32_t *i, uint32_t
*l)
+{
+ buf += *i;
+ if (*l >= n - 8) {
+ (*i)++;
+ *l = 8 - n + (*l);
+ val <<= *l;
+ *buf = *buf | ((val >> 8) & 0xff);
+ *(++buf) = val & 0xff;
+ if (*l == 0) {
+ *l = 8;
+ (*i)++;
+ *(++buf) = 0;
+ }
+ } else {
+ (*i)++; (*i)++;
+ *l = 16 - n + (*l);
+ val <<= *l;
+ *buf = *buf | ((val >> 16) & 0xff);
+ *(++buf) = (val >> 8) & 0xff;
+ *(++buf) = val & 0xff;
+ }
+}
+
+/* Inserts 17 to 24 bits into the output buffer. */
+static void __inline
+putbits24(uint8_t *buf, uint32_t val, const uint32_t n, uint32_t *i, uint32_t
*l)
+{
+ buf += *i;
+ if (*l >= n - 16) {
+ (*i)++; (*i)++;
+ *l = 16 - n + (*l);
+ val <<= *l;
+ *buf = *buf | ((val >> 16) & 0xff);
+ *(++buf) = (val >> 8) & 0xff;
+ *(++buf) = val & 0xff;
+ if (*l == 0) {
+ *l = 8;
+ (*i)++;
+ *(++buf) = 0;
+ }
+ } else {
+ (*i)++; (*i)++; (*i)++;
+ *l = 24 - n + (*l);
+ val <<= *l;
+ *buf = *buf | ((val >> 24) & 0xff);
+ *(++buf) = (val >> 16) & 0xff;
+ *(++buf) = (val >> 8) & 0xff;
+ *(++buf) = val & 0xff;
+ }
+}
+
+size_t MPPC_SizeOfCompressionHistory(void)
+{
+ return (sizeof(struct MPPC_comp_state));
+}
+
+void MPPC_InitCompressionHistory(char *history)
+{
+ struct MPPC_comp_state *state = (struct MPPC_comp_state*)history;
+
+ bzero(history, sizeof(struct MPPC_comp_state));
+ state->histptr = MPPE_HIST_LEN;
+}
+
+int MPPC_Compress(u_char **src, u_char **dst, u_long *srcCnt, u_long *dstCnt,
char *history, int flags, int undef)
+{
+ struct MPPC_comp_state *state = (struct MPPC_comp_state*)history;
+ uint32_t olen, off, len, idx, i, l;
+ uint8_t *hist, *sbuf, *p, *q, *r, *s;
+ int rtn = MPPC_OK;
+
+ /*
+ * At this point, to avoid possible buffer overflow caused by packet
+ * expansion during/after compression, we should make sure we have
+ * space for the worst case.
+
+ * Maximum MPPC packet expansion is 12.5%. This is the worst case when
+ * all octets in the input buffer are >= 0x80 and we cannot find any
+ * repeated tokens.
+ */
+ if (*dstCnt < (*srcCnt * 9 / 8 + 2)) {
+ rtn &= ~MPPC_OK;
+ return (rtn);
+ }
+
+ /* We can't compress more then MPPE_HIST_LEN bytes in a call. */
+ if (*srcCnt > MPPE_HIST_LEN) {
+ rtn &= ~MPPC_OK;
+ return (rtn);
+ }
+
+ hist = state->hist + MPPE_HIST_LEN;
+ /* check if there is enough room at the end of the history */
+ if (state->histptr + *srcCnt >= 2*MPPE_HIST_LEN) {
+ rtn |= MPPC_RESTART_HISTORY;
+ state->histptr = MPPE_HIST_LEN;
+ memcpy(state->hist, hist, MPPE_HIST_LEN);
+ }
+ /* Add packet to the history. */
+ sbuf = state->hist + state->histptr;
+ memcpy(sbuf, *src, *srcCnt);
+ state->histptr += *srcCnt;
+
+ /* compress data */
+ r = sbuf + *srcCnt;
+ **dst = olen = i = 0;
+ l = 8;
+ while (i < *srcCnt - 2) {
+ s = q = sbuf + i;
+
+ /* Prognose matching position using hash function. */
+ idx = HASH(s);
+ p = hist + state->hash[idx];
+ state->hash[idx] = (uint16_t) (s - hist);
+ if (p > s) /* It was before MPPC_RESTART_HISTORY. */
+ p -= MPPE_HIST_LEN; /* Try previous history buffer. */
+ off = s - p;
+
+ /* Check our prognosis. */
+ if (off > MPPE_HIST_LEN - 1 || off < 1 || *p++ != *s++ ||
+ *p++ != *s++ || *p++ != *s++) {
+ /* No match found; encode literal byte. */
+ if ((*src)[i] < 0x80) { /* literal byte < 0x80 */
+ putbits8(*dst, (uint32_t) (*src)[i], 8, &olen, &l);
+ } else { /* literal byte >= 0x80 */
+ putbits16(*dst, (uint32_t) (0x100|((*src)[i]&0x7f)), 9,
+ &olen, &l);
+ }
+ ++i;
+ continue;
+ }
+
+ /* Find length of the matching fragment */
+#if defined(__amd64__) || defined(__i386__)
+ /* Optimization for CPUs without strict data aligning requirements */
+ while ((*((uint32_t*)p) == *((uint32_t*)s)) && (s < (r - 3))) {
+ p+=4;
+ s+=4;
+ }
+#endif
+ while((*p++ == *s++) && (s <= r));
+ len = s - q - 1;
+ i += len;
+
+ /* At least 3 character match found; code data. */
+ /* Encode offset. */
+ if (off < 64) { /* 10-bit offset; 0 <= offset < 64 */
+ putbits16(*dst, 0x3c0|off, 10, &olen, &l);
+ } else if (off < 320) { /* 12-bit offset; 64 <= offset < 320 */
+ putbits16(*dst, 0xe00|(off-64), 12, &olen, &l);
+ } else if (off < 8192) { /* 16-bit offset; 320 <= offset < 8192
*/
+ putbits16(*dst, 0xc000|(off-320), 16, &olen, &l);
+ } else { /* NOTREACHED */
+ rtn &= ~MPPC_OK;
+ return rtn;
+ }
+
+ /* Encode length of match. */
+ if (len < 4) { /* length = 3 */
+ putbits8(*dst, 0, 1, &olen, &l);
+ } else if (len < 8) { /* 4 <= length < 8 */
+ putbits8(*dst, 0x08|(len&0x03), 4, &olen, &l);
+ } else if (len < 16) { /* 8 <= length < 16 */
+ putbits8(*dst, 0x30|(len&0x07), 6, &olen, &l);
+ } else if (len < 32) { /* 16 <= length < 32 */
+ putbits8(*dst, 0xe0|(len&0x0f), 8, &olen, &l);
+ } else if (len < 64) { /* 32 <= length < 64 */
+ putbits16(*dst, 0x3c0|(len&0x1f), 10, &olen, &l);
+ } else if (len < 128) { /* 64 <= length < 128 */
+ putbits16(*dst, 0xf80|(len&0x3f), 12, &olen, &l);
+ } else if (len < 256) { /* 128 <= length < 256 */
+ putbits16(*dst, 0x3f00|(len&0x7f), 14, &olen, &l);
+ } else if (len < 512) { /* 256 <= length < 512 */
+ putbits16(*dst, 0xfe00|(len&0xff), 16, &olen, &l);
+ } else if (len < 1024) { /* 512 <= length < 1024 */
+ putbits24(*dst, 0x3fc00|(len&0x1ff), 18, &olen, &l);
+ } else if (len < 2048) { /* 1024 <= length < 2048 */
+ putbits24(*dst, 0xff800|(len&0x3ff), 20, &olen, &l);
+ } else if (len < 4096) { /* 2048 <= length < 4096 */
+ putbits24(*dst, 0x3ff000|(len&0x7ff), 22, &olen, &l);
+ } else if (len < 8192) { /* 4096 <= length < 8192 */
+ putbits24(*dst, 0xffe000|(len&0xfff), 24, &olen, &l);
+ } else { /* NOTREACHED */
+ rtn &= ~MPPC_OK;
+ return (rtn);
+ }
+ }
+
+ /* Add remaining octets to the output. */
+ while(*srcCnt - i > 0) {
+ if ((*src)[i] < 0x80) { /* literal byte < 0x80 */
+ putbits8(*dst, (uint32_t) (*src)[i++], 8, &olen, &l);
+ } else { /* literal byte >= 0x80 */
+ putbits16(*dst, (uint32_t) (0x100|((*src)[i++]&0x7f)), 9, &olen,
+ &l);
+ }
+ }
+
+ /* Reset unused bits of the last output octet. */
+ if ((l != 0) && (l != 8)) {
+ putbits8(*dst, 0, l, &olen, &l);
+ }
+
+ /* If result is bigger then original, set flag and flush history. */
+ if ((*srcCnt < olen) || ((flags & MPPC_SAVE_HISTORY) == 0)) {
+ if (*srcCnt < olen)
+ rtn |= MPPC_EXPANDED;
+ bzero(history, sizeof(struct MPPC_comp_state));
+ state->histptr = MPPE_HIST_LEN;
+ }
+
+ *src += *srcCnt;
+ *srcCnt = 0;
+ *dst += olen;
+ *dstCnt -= olen;
+
+ return (rtn);
+}
Copied: stable/10/sys/net/mppcd.c (from r301549, head/sys/net/mppcd.c)
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ stable/10/sys/net/mppcd.c Tue Jun 21 15:47:54 2016 (r302061, copy
of r301549, head/sys/net/mppcd.c)
@@ -0,0 +1,284 @@
+/*-
+ * Copyright (c) 2002-2004 Jan Dubiec <j...@slackware.pl>
+ * Copyright (c) 2007 Alexander Motin <m...@freebsd.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice unmodified, this list of conditions, and the following
+ * disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * MPPC decompression library.
+ * Version 1.0
+ *
+ * Note that Hi/Fn (later acquired by Exar Corporation) held US patents
+ * on some implementation-critical aspects of MPPC compression.
+ * These patents lapsed due to non-payment of fees in 2007 and by 2015
+ * expired altogether.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+
+#include <net/mppc.h>
+
+#define MPPE_HIST_LEN 8192
+
+struct MPPC_decomp_state {
+ uint8_t hist[2*MPPE_HIST_LEN];
+ uint16_t histptr;
+};
+
+static uint32_t __inline
+getbits(const uint8_t *buf, const uint32_t n, uint32_t *i, uint32_t *l)
+{
+ static const uint32_t m[] = {0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f,
0x7f, 0xff};
+ uint32_t res, ol;
+
+ ol = *l;
+ if (*l >= n) {
+ *l = (*l) - n;
+ res = (buf[*i] & m[ol]) >> (*l);
+ if (*l == 0) {
+ *l = 8;
+ (*i)++;
+ }
+ } else {
+ *l = 8 - n + (*l);
+ res = (buf[(*i)++] & m[ol]) << 8;
+ res = (res | buf[*i]) >> (*l);
+ }
+
+ return (res);
+}
+
+static uint32_t __inline
+getbyte(const uint8_t *buf, const uint32_t i, const uint32_t l)
+{
+ if (l == 8) {
+ return (buf[i]);
+ } else {
+ return ((((buf[i] << 8) | buf[i+1]) >> l) & 0xff);
+ }
+}
+
+static void __inline
+lamecopy(uint8_t *dst, uint8_t *src, uint32_t len)
+{
+ while (len--)
+ *dst++ = *src++;
+}
+
+size_t MPPC_SizeOfDecompressionHistory(void)
+{
+ return (sizeof(struct MPPC_decomp_state));
+}
+
+void MPPC_InitDecompressionHistory(char *history)
+{
+ struct MPPC_decomp_state *state = (struct MPPC_decomp_state*)history;
+
+ bzero(history, sizeof(struct MPPC_decomp_state));
+ state->histptr = MPPE_HIST_LEN;
+}
+
+int MPPC_Decompress(u_char **src, u_char **dst, u_long *srcCnt, u_long
*dstCnt, char *history, int flags)
+{
+ struct MPPC_decomp_state *state = (struct MPPC_decomp_state*)history;
+ uint32_t olen, off, len, bits, val, sig, i, l;
+ uint8_t *hist, *s;
+ u_char *isrc = *src;
+ int rtn = MPPC_OK;
+
+ if ((flags & MPPC_RESTART_HISTORY) != 0) {
+ memcpy(state->hist, state->hist + MPPE_HIST_LEN, MPPE_HIST_LEN);
+ state->histptr = MPPE_HIST_LEN;
+ }
+
+ hist = state->hist + state->histptr;
+ olen = len = i = 0;
+ l = 8;
+ bits = *srcCnt * 8;
+ while (bits >= 8) {
+ val = getbyte(isrc, i++, l);
+ if (val < 0x80) { /* literal byte < 0x80 */
+ if (state->histptr < 2*MPPE_HIST_LEN) {
+ /* Copy uncompressed byte to the history. */
+ (state->hist)[(state->histptr)++] = (uint8_t) val;
+ } else {
+ /* Buffer overflow; drop packet. */
+ rtn &= ~MPPC_OK;
+ return rtn;
+ }
+ olen++;
+ bits -= 8;
+ continue;
+ }
+
+ sig = val & 0xc0;
+ if (sig == 0x80) { /* literal byte >= 0x80 */
+ if (state->histptr < 2*MPPE_HIST_LEN) {
+ /* Copy uncompressed byte to the history. */
+ (state->hist)[(state->histptr)++] =
+ (uint8_t) (0x80|((val&0x3f)<<1)|getbits(isrc, 1 , &i ,&l));
+ } else {
+ /* buffer overflow; drop packet */
+ rtn &= ~MPPC_OK;
+ return (rtn);
+ }
+ olen++;
+ bits -= 9;
+ continue;
+ }
+
+ /* Not a literal byte so it must be an (offset,length) pair */
+ /* decode offset */
+ sig = val & 0xf0;
+ if (sig == 0xf0) { /* 10-bit offset; 0 <= offset < 64 */
+ off = (((val&0x0f)<<2)|getbits(isrc, 2 , &i ,&l));
+ bits -= 10;
+ } else {
+ if (sig == 0xe0) { /* 12-bit offset; 64 <= offset < 320 */
+ off = ((((val&0x0f)<<4)|getbits(isrc, 4 , &i ,&l))+64);
+ bits -= 12;
+ } else {
+ if ((sig&0xe0) == 0xc0) {/* 16-bit offset; 320 <= offset < 8192
*/
+ off = ((((val&0x1f)<<8)|getbyte(isrc, i++, l))+320);
+ bits -= 16;
+ if (off > MPPE_HIST_LEN - 1) {
+ rtn &= ~MPPC_OK;
+ return (rtn);
+ }
+ } else { /* NOTREACHED */
+ rtn &= ~MPPC_OK;
+ return (rtn);
+ }
+ }
+ }
+ /* Decode length of match. */
+ val = getbyte(isrc, i, l);
+ if ((val & 0x80) == 0x00) { /* len = 3 */
+ len = 3;
+ bits--;
+ getbits(isrc, 1 , &i ,&l);
+ } else if ((val & 0xc0) == 0x80) { /* 4 <= len < 8 */
+ len = 0x04 | ((val>>4) & 0x03);
+ bits -= 4;
+ getbits(isrc, 4 , &i ,&l);
+ } else if ((val & 0xe0) == 0xc0) { /* 8 <= len < 16 */
+ len = 0x08 | ((val>>2) & 0x07);
+ bits -= 6;
+ getbits(isrc, 6 , &i ,&l);
+ } else if ((val & 0xf0) == 0xe0) { /* 16 <= len < 32 */
+ len = 0x10 | (val & 0x0f);
+ bits -= 8;
+ i++;
+ } else {
+ bits -= 8;
+ val = (val << 8) | getbyte(isrc, ++i, l);
+ if ((val & 0xf800) == 0xf000) { /* 32 <= len < 64 */
+ len = 0x0020 | ((val >> 6) & 0x001f);
+ bits -= 2;
+ getbits(isrc, 2 , &i ,&l);
+ } else if ((val & 0xfc00) == 0xf800) { /* 64 <= len < 128 */
+ len = 0x0040 | ((val >> 4) & 0x003f);
+ bits -= 4;
+ getbits(isrc, 4 , &i ,&l);
+ } else if ((val & 0xfe00) == 0xfc00) { /* 128 <= len < 256 */
+ len = 0x0080 | ((val >> 2) & 0x007f);
+ bits -= 6;
+ getbits(isrc, 6 , &i ,&l);
+ } else if ((val & 0xff00) == 0xfe00) { /* 256 <= len < 512 */
+ len = 0x0100 | (val & 0x00ff);
+ bits -= 8;
+ i++;
+ } else {
+ bits -= 8;
+ val = (val << 8) | getbyte(isrc, ++i, l);
+ if ((val & 0xff8000) == 0xff0000) { /* 512 <= len < 1024 */
+ len = 0x000200 | ((val >> 6) & 0x0001ff);
+ bits -= 2;
+ getbits(isrc, 2 , &i ,&l);
+ } else if ((val & 0xffc000) == 0xff8000) {/* 1024 <= len < 2048
*/
+ len = 0x000400 | ((val >> 4) & 0x0003ff);
+ bits -= 4;
+ getbits(isrc, 4 , &i ,&l);
+ } else if ((val & 0xffe000) == 0xffc000) {/* 2048 <= len < 4096
*/
+ len = 0x000800 | ((val >> 2) & 0x0007ff);
+ bits -= 6;
+ getbits(isrc, 6 , &i ,&l);
+ } else if ((val & 0xfff000) == 0xffe000) {/* 4096 <= len < 8192
*/
+ len = 0x001000 | (val & 0x000fff);
+ bits -= 8;
+ i++;
+ } else { /* NOTREACHED */
+ rtn &= ~MPPC_OK;
+ return (rtn);
+ }
+ }
+ }
+
+ s = state->hist + state->histptr;
+ state->histptr += len;
+ olen += len;
+ if (state->histptr < 2*MPPE_HIST_LEN) {
+ /* Copy uncompressed bytes to the history. */
+
+ /*
+ * In some cases len may be greater than off. It means that memory
+ * areas pointed by s and s-off overlap. To decode that strange case
+ * data should be copied exactly by address increasing to make
+ * some data repeated.
+ */
+ lamecopy(s, s - off, len);
+ } else {
+ /* Buffer overflow; drop packet. */
+ rtn &= ~MPPC_OK;
+ return (rtn);
+ }
+ }
+
+ /* Do PFC decompression. */
+ len = olen;
+ if ((hist[0] & 0x01) != 0) {
+ (*dst)[0] = 0;
+ (*dst)++;
+ len++;
+ }
+
+ if (len <= *dstCnt) {
+ /* Copy uncompressed packet to the output buffer. */
+ memcpy(*dst, hist, olen);
+ } else {
+ /* Buffer overflow; drop packet. */
+ rtn |= MPPC_DEST_EXHAUSTED;
+ }
+
+ *src += *srcCnt;
+ *srcCnt = 0;
+ *dst += len;
+ *dstCnt -= len;
+
+ return (rtn);
+}
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