Date: Tue, 21 Jun 2016 15:47:54 +0000 (UTC) From: "Pedro F. Giffuni" <pfg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r302061 - in stable/10: share/man/man4 sys/modules/netgraph/mppc sys/net Message-ID: <201606211547.u5LFlsx7033903@repo.freebsd.org>
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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 <mav@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 <jdx@slackware.pl> + * Copyright (c) 2007 Alexander Motin <mav@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 <jdx@slackware.pl> + * Copyright (c) 2007 Alexander Motin <mav@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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