352 lines
9.0 KiB
C
352 lines
9.0 KiB
C
/*
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* ppp_deflate.c - interface the zlib procedures for Deflate compression
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* and decompression (as used by gzip) to the PPP code.
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*
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* Copyright (c) 1994 The Australian National University.
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* All rights reserved.
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*
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* Permission to use, copy, modify, and distribute this software and its
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* documentation is hereby granted, provided that the above copyright
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* notice appears in all copies. This software is provided without any
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* warranty, express or implied. The Australian National University
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* makes no representations about the suitability of this software for
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* any purpose.
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*
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* IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY
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* PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
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* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
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* THE AUSTRALIAN NATIONAL UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*
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* THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES,
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* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
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* ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO
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* OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS,
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* OR MODIFICATIONS.
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*
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* $Id: deflate.c,v 1.5 2002/05/30 12:29:04 agc Exp $
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*/
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#include <sys/types.h>
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#include <stdio.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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#include "pppdump.h"
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#include <net/ppp_defs.h>
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#include <net/ppp-comp.h>
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#include <zlib.h>
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#if DO_DEFLATE
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#define DEFLATE_DEBUG 1
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/*
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* State for a Deflate (de)compressor.
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*/
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struct deflate_state {
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int seqno;
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int w_size;
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int unit;
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int hdrlen;
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int mru;
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int debug;
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z_stream strm;
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struct compstat stats;
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};
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#define DEFLATE_OVHD 2 /* Deflate overhead/packet */
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static void *z_alloc __P((void *, u_int items, u_int size));
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static void z_free __P((void *, void *ptr, u_int nb));
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static void *z_decomp_alloc __P((u_char *options, int opt_len));
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static void z_decomp_free __P((void *state));
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static int z_decomp_init __P((void *state, u_char *options, int opt_len,
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int unit, int hdrlen, int mru, int debug));
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static void z_incomp __P((void *state, PACKETPTR mi));
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static int z_decompress __P((void *state, PACKETPTR mi, PACKETPTR *mo));
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static void z_decomp_reset __P((void *state));
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static void z_comp_stats __P((void *state, struct compstat *stats));
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/*
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* Procedures exported to if_ppp.c.
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*/
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struct compressor ppp_deflate = {
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CI_DEFLATE, /* compress_proto */
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NULL, /* comp_alloc */
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NULL, /* comp_free */
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NULL, /* comp_init */
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NULL, /* comp_reset */
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NULL, /* comp_compress */
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NULL, /* comp_stat */
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z_decomp_alloc, /* decomp_alloc */
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z_decomp_free, /* decomp_free */
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z_decomp_init, /* decomp_init */
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z_decomp_reset, /* decomp_reset */
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z_decompress, /* decompress */
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z_incomp, /* incomp */
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z_comp_stats, /* decomp_stat */
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};
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/*
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* Space allocation and freeing routines for use by zlib routines.
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*/
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static void *
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z_alloc(notused, items, size)
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void *notused;
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u_int items, size;
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{
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return malloc(items * size);
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}
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static void
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z_free(notused, ptr, nbytes)
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void *notused;
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void *ptr;
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u_int nbytes;
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{
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free(ptr);
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}
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static void
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z_comp_stats(arg, stats)
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void *arg;
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struct compstat *stats;
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{
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struct deflate_state *state = (struct deflate_state *) arg;
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u_int out;
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*stats = state->stats;
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stats->ratio = stats->unc_bytes;
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out = stats->comp_bytes + stats->unc_bytes;
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if (stats->ratio <= 0x7ffffff)
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stats->ratio <<= 8;
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else
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out >>= 8;
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if (out != 0)
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stats->ratio /= out;
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}
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/*
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* Allocate space for a decompressor.
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*/
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static void *
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z_decomp_alloc(options, opt_len)
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u_char *options;
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int opt_len;
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{
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struct deflate_state *state;
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int w_size;
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if (opt_len != CILEN_DEFLATE || options[0] != CI_DEFLATE
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|| options[1] != CILEN_DEFLATE
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|| DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
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|| options[3] != DEFLATE_CHK_SEQUENCE)
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return NULL;
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w_size = DEFLATE_SIZE(options[2]);
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if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE)
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return NULL;
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state = (struct deflate_state *) malloc(sizeof(*state));
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if (state == NULL)
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return NULL;
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state->strm.next_out = NULL;
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state->strm.zalloc = (alloc_func) z_alloc;
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state->strm.zfree = (free_func) z_free;
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if (inflateInit2(&state->strm, -w_size) != Z_OK) {
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free(state);
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return NULL;
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}
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state->w_size = w_size;
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memset(&state->stats, 0, sizeof(state->stats));
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return (void *) state;
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}
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static void
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z_decomp_free(arg)
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void *arg;
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{
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struct deflate_state *state = (struct deflate_state *) arg;
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inflateEnd(&state->strm);
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free(state);
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}
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static int
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z_decomp_init(arg, options, opt_len, unit, hdrlen, mru, debug)
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void *arg;
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u_char *options;
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int opt_len, unit, hdrlen, mru, debug;
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{
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struct deflate_state *state = (struct deflate_state *) arg;
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if (opt_len < CILEN_DEFLATE || options[0] != CI_DEFLATE
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|| options[1] != CILEN_DEFLATE
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|| DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL
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|| DEFLATE_SIZE(options[2]) != state->w_size
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|| options[3] != DEFLATE_CHK_SEQUENCE)
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return 0;
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state->seqno = 0;
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state->unit = unit;
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state->hdrlen = hdrlen;
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state->debug = debug;
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state->mru = mru;
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inflateReset(&state->strm);
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return 1;
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}
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static void
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z_decomp_reset(arg)
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void *arg;
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{
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struct deflate_state *state = (struct deflate_state *) arg;
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state->seqno = 0;
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inflateReset(&state->strm);
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}
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/*
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* Decompress a Deflate-compressed packet.
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*
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* Because of patent problems, we return DECOMP_ERROR for errors
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* found by inspecting the input data and for system problems, but
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* DECOMP_FATALERROR for any errors which could possibly be said to
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* be being detected "after" decompression. For DECOMP_ERROR,
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* we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be
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* infringing a patent of Motorola's if we do, so we take CCP down
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* instead.
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*
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* Given that the frame has the correct sequence number and a good FCS,
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* errors such as invalid codes in the input most likely indicate a
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* bug, so we return DECOMP_FATALERROR for them in order to turn off
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* compression, even though they are detected by inspecting the input.
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*/
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static int
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z_decompress(arg, mi, mo)
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void *arg;
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PACKETPTR mi;
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PACKETPTR *mo;
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{
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struct deflate_state *state = (struct deflate_state *) arg;
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u_char *rptr, *wptr;
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int rlen, olen;
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int seq, r;
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rptr = mi->buf;
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if (*rptr == 0)
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++rptr;
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++rptr;
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/* Check the sequence number. */
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seq = (rptr[0] << 8) + rptr[1];
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rptr += 2;
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if (seq != state->seqno) {
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#if !DEFLATE_DEBUG
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if (state->debug)
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#endif
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printf("z_decompress%d: bad seq # %d, expected %d\n",
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state->unit, seq, state->seqno);
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return DECOMP_ERROR;
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}
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++state->seqno;
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/*
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* Set up to call inflate.
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*/
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wptr = (*mo)->buf;
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state->strm.next_in = rptr;
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state->strm.avail_in = mi->buf + mi->len - rptr;
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rlen = state->strm.avail_in + PPP_HDRLEN + DEFLATE_OVHD;
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state->strm.next_out = wptr;
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state->strm.avail_out = state->mru + 2;
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r = inflate(&state->strm, Z_PACKET_FLUSH);
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if (r != Z_OK) {
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#if !DEFLATE_DEBUG
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if (state->debug)
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#endif
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printf("z_decompress%d: inflate returned %d (%s)\n",
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state->unit, r, (state->strm.msg? state->strm.msg: ""));
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return DECOMP_FATALERROR;
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}
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olen = state->mru + 2 - state->strm.avail_out;
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(*mo)->len = olen;
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if ((wptr[0] & 1) != 0)
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++olen; /* for suppressed protocol high byte */
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olen += 2; /* for address, control */
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#if DEFLATE_DEBUG
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if (olen > state->mru + PPP_HDRLEN)
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printf("ppp_deflate%d: exceeded mru (%d > %d)\n",
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state->unit, olen, state->mru + PPP_HDRLEN);
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#endif
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state->stats.unc_bytes += olen;
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state->stats.unc_packets++;
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state->stats.comp_bytes += rlen;
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state->stats.comp_packets++;
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return DECOMP_OK;
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}
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/*
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* Incompressible data has arrived - add it to the history.
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*/
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static void
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z_incomp(arg, mi)
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void *arg;
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PACKETPTR mi;
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{
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struct deflate_state *state = (struct deflate_state *) arg;
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u_char *rptr;
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int rlen, proto, r;
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/*
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* Check that the protocol is one we handle.
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*/
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rptr = mi->buf;
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proto = rptr[0];
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if ((proto & 1) == 0)
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proto = (proto << 8) + rptr[1];
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if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
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return;
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++state->seqno;
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if (rptr[0] == 0)
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++rptr;
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rlen = mi->buf + mi->len - rptr;
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state->strm.next_in = rptr;
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state->strm.avail_in = rlen;
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r = inflateIncomp(&state->strm);
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if (r != Z_OK) {
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/* gak! */
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#if !DEFLATE_DEBUG
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if (state->debug)
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#endif
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printf("z_incomp%d: inflateIncomp returned %d (%s)\n",
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state->unit, r, (state->strm.msg? state->strm.msg: ""));
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return;
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}
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/*
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* Update stats.
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*/
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if (proto <= 0xff)
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++rlen;
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rlen += 2;
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state->stats.inc_bytes += rlen;
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state->stats.inc_packets++;
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state->stats.unc_bytes += rlen;
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state->stats.unc_packets++;
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}
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#endif /* DO_DEFLATE */
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