/* * ppp_deflate.c - interface the zlib procedures for Deflate compression * and decompression (as used by gzip) to the PPP code. * * Copyright (c) 1994 The Australian National University. * All rights reserved. * * Permission to use, copy, modify, and distribute this software and its * documentation is hereby granted, provided that the above copyright * notice appears in all copies. This software is provided without any * warranty, express or implied. The Australian National University * makes no representations about the suitability of this software for * any purpose. * * IN NO EVENT SHALL THE AUSTRALIAN NATIONAL UNIVERSITY BE LIABLE TO ANY * PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF * THE AUSTRALIAN NATIONAL UNIVERSITY HAS BEEN ADVISED OF THE POSSIBILITY * OF SUCH DAMAGE. * * THE AUSTRALIAN NATIONAL UNIVERSITY SPECIFICALLY DISCLAIMS ANY WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY * AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS * ON AN "AS IS" BASIS, AND THE AUSTRALIAN NATIONAL UNIVERSITY HAS NO * OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, * OR MODIFICATIONS. * * $Id: deflate.c,v 1.3 1999/04/16 11:35:59 paulus Exp $ */ #include <sys/types.h> #include <stddef.h> #include <stdlib.h> #ifdef PPP_DEFS_IN_NET #include <net/ppp_defs.h> #else #include "ppp_defs.h" #endif #include "ppp-comp.h" #include "zlib.h" #if DO_DEFLATE #define DEFLATE_DEBUG 1 /* * State for a Deflate (de)compressor. */ struct deflate_state { int seqno; int w_size; int unit; int hdrlen; int mru; int debug; z_stream strm; struct compstat stats; }; #define DEFLATE_OVHD 2 /* Deflate overhead/packet */ static void *z_alloc __P((void *, u_int items, u_int size)); static void z_free __P((void *, void *ptr, u_int nb)); static void *z_decomp_alloc __P((u_char *options, int opt_len)); static void z_decomp_free __P((void *state)); static int z_decomp_init __P((void *state, u_char *options, int opt_len, int unit, int hdrlen, int mru, int debug)); static void z_incomp __P((void *state, u_char *dmsg, int len)); static int z_decompress __P((void *state, u_char *cmp, int inlen, u_char *dmp, int *outlenp)); static void z_decomp_reset __P((void *state)); static void z_comp_stats __P((void *state, struct compstat *stats)); /* * Procedures exported to if_ppp.c. */ struct compressor ppp_deflate = { CI_DEFLATE, /* compress_proto */ z_decomp_alloc, /* decomp_alloc */ z_decomp_free, /* decomp_free */ z_decomp_init, /* decomp_init */ z_decomp_reset, /* decomp_reset */ z_decompress, /* decompress */ z_incomp, /* incomp */ z_comp_stats, /* decomp_stat */ }; /* * Space allocation and freeing routines for use by zlib routines. */ static void * z_alloc(notused, items, size) void *notused; u_int items, size; { return malloc(items * size); } static void z_free(notused, ptr, nbytes) void *notused; void *ptr; u_int nbytes; { free(ptr); } static void z_comp_stats(arg, stats) void *arg; struct compstat *stats; { struct deflate_state *state = (struct deflate_state *) arg; u_int out; *stats = state->stats; stats->ratio = stats->unc_bytes; out = stats->comp_bytes + stats->unc_bytes; if (stats->ratio <= 0x7ffffff) stats->ratio <<= 8; else out >>= 8; if (out != 0) stats->ratio /= out; } /* * Allocate space for a decompressor. */ static void * z_decomp_alloc(options, opt_len) u_char *options; int opt_len; { struct deflate_state *state; int w_size; if (opt_len != CILEN_DEFLATE || options[0] != CI_DEFLATE || options[1] != CILEN_DEFLATE || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL || options[3] != DEFLATE_CHK_SEQUENCE) return NULL; w_size = DEFLATE_SIZE(options[2]); if (w_size < DEFLATE_MIN_SIZE || w_size > DEFLATE_MAX_SIZE) return NULL; state = (struct deflate_state *) malloc(sizeof(*state)); if (state == NULL) return NULL; state->strm.next_out = NULL; state->strm.zalloc = (alloc_func) z_alloc; state->strm.zfree = (free_func) z_free; if (inflateInit2(&state->strm, -w_size) != Z_OK) { free(state); return NULL; } state->w_size = w_size; memset(&state->stats, 0, sizeof(state->stats)); return (void *) state; } static void z_decomp_free(arg) void *arg; { struct deflate_state *state = (struct deflate_state *) arg; inflateEnd(&state->strm); free(state); } static int z_decomp_init(arg, options, opt_len, unit, hdrlen, mru, debug) void *arg; u_char *options; int opt_len, unit, hdrlen, mru, debug; { struct deflate_state *state = (struct deflate_state *) arg; if (opt_len < CILEN_DEFLATE || options[0] != CI_DEFLATE || options[1] != CILEN_DEFLATE || DEFLATE_METHOD(options[2]) != DEFLATE_METHOD_VAL || DEFLATE_SIZE(options[2]) != state->w_size || options[3] != DEFLATE_CHK_SEQUENCE) return 0; state->seqno = 0; state->unit = unit; state->hdrlen = hdrlen; state->debug = debug; state->mru = mru; inflateReset(&state->strm); return 1; } static void z_decomp_reset(arg) void *arg; { struct deflate_state *state = (struct deflate_state *) arg; state->seqno = 0; inflateReset(&state->strm); } /* * Decompress a Deflate-compressed packet. * * Because of patent problems, we return DECOMP_ERROR for errors * found by inspecting the input data and for system problems, but * DECOMP_FATALERROR for any errors which could possibly be said to * be being detected "after" decompression. For DECOMP_ERROR, * we can issue a CCP reset-request; for DECOMP_FATALERROR, we may be * infringing a patent of Motorola's if we do, so we take CCP down * instead. * * Given that the frame has the correct sequence number and a good FCS, * errors such as invalid codes in the input most likely indicate a * bug, so we return DECOMP_FATALERROR for them in order to turn off * compression, even though they are detected by inspecting the input. */ static int z_decompress(arg, mi, inlen, mo, outlenp) void *arg; u_char *mi, *mo; int inlen, *outlenp; { struct deflate_state *state = (struct deflate_state *) arg; u_char *rptr, *wptr; int rlen, olen, ospace; int seq, i, flush, r, decode_proto; rptr = mi; if (*rptr == 0) ++rptr; ++rptr; /* Check the sequence number. */ seq = (rptr[0] << 8) + rptr[1]; rptr += 2; if (seq != state->seqno) { #if !DEFLATE_DEBUG if (state->debug) #endif printf("z_decompress%d: bad seq # %d, expected %d\n", state->unit, seq, state->seqno); return DECOMP_ERROR; } ++state->seqno; /* * Set up to call inflate. */ wptr = mo; state->strm.next_in = rptr; state->strm.avail_in = mi + inlen - rptr; rlen = state->strm.avail_in + PPP_HDRLEN + DEFLATE_OVHD; state->strm.next_out = wptr; state->strm.avail_out = state->mru + 2; r = inflate(&state->strm, Z_PACKET_FLUSH); if (r != Z_OK) { #if !DEFLATE_DEBUG if (state->debug) #endif printf("z_decompress%d: inflate returned %d (%s)\n", state->unit, r, (state->strm.msg? state->strm.msg: "")); return DECOMP_FATALERROR; } olen = state->mru + 2 - state->strm.avail_out; *outlenp = olen; if ((wptr[0] & 1) != 0) ++olen; /* for suppressed protocol high byte */ olen += 2; /* for address, control */ #if DEFLATE_DEBUG if (olen > state->mru + PPP_HDRLEN) printf("ppp_deflate%d: exceeded mru (%d > %d)\n", state->unit, olen, state->mru + PPP_HDRLEN); #endif state->stats.unc_bytes += olen; state->stats.unc_packets++; state->stats.comp_bytes += rlen; state->stats.comp_packets++; return DECOMP_OK; } /* * Incompressible data has arrived - add it to the history. */ static void z_incomp(arg, mi, mlen) void *arg; u_char *mi; int mlen; { struct deflate_state *state = (struct deflate_state *) arg; u_char *rptr; int rlen, proto, r; /* * Check that the protocol is one we handle. */ rptr = mi; proto = rptr[0]; if ((proto & 1) == 0) proto = (proto << 8) + rptr[1]; if (proto > 0x3fff || proto == 0xfd || proto == 0xfb) return; ++state->seqno; if (rptr[0] == 0) ++rptr; rlen = mi + mlen - rptr; state->strm.next_in = rptr; state->strm.avail_in = rlen; r = inflateIncomp(&state->strm); if (r != Z_OK) { /* gak! */ #if !DEFLATE_DEBUG if (state->debug) #endif printf("z_incomp%d: inflateIncomp returned %d (%s)\n", state->unit, r, (state->strm.msg? state->strm.msg: "")); return; } /* * Update stats. */ if (proto <= 0xff) ++rlen; rlen += 2; state->stats.inc_bytes += rlen; state->stats.inc_packets++; state->stats.unc_bytes += rlen; state->stats.unc_packets++; } #endif /* DO_DEFLATE */