--- /dev/null
+/*
+ * 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 1.1 1999/03/23 03:21:57 paulus Exp $
+ */
+
+#include <sys/types.h>
+#include <stdlib.h>
+#include "ppp_defs.h"
+#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;
+ bzero(&state->stats, 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 */
projects / ppp.git / blobdiff