FreeBSD/Linux Kernel Cross Reference
sys/bsd/net/ppp_deflate.c

     /*
      * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
      *
      * @APPLE_LICENSE_HEADER_START@
      * 
      * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
      * 
      * This file contains Original Code and/or Modifications of Original Code
      * as defined in and that are subject to the Apple Public Source License
     * Version 2.0 (the 'License'). You may not use this file except in
     * compliance with the License. Please obtain a copy of the License at
     * http://www.opensource.apple.com/apsl/ and read it before using this
     * file.
     * 
     * The Original Code and all software distributed under the License are
     * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
     * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
     * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
     * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
     * Please see the License for the specific language governing rights and
     * limitations under the License.
     * 
     * @APPLE_LICENSE_HEADER_END@
     */
    /*
     * ppp_deflate.c - interface the zlib procedures for Deflate compression
     * and decompression (as used by gzip) to the PPP code.
     * This version is for use with mbufs on BSD-derived systems.
     *
     * 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.
     */
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/malloc.h>
    #include <sys/mbuf.h>
    #include <net/ppp_defs.h>
    #include <net/zlib.h>
    
    #define PACKETPTR       struct mbuf *
    #include <net/ppp_comp.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));
    static void     *z_comp_alloc __P((u_char *options, int opt_len));
    static void     *z_decomp_alloc __P((u_char *options, int opt_len));
    static void     z_comp_free __P((void *state));
    static void     z_decomp_free __P((void *state));
    static int      z_comp_init __P((void *state, u_char *options, int opt_len,
                                     int unit, int hdrlen, int debug));
    static int      z_decomp_init __P((void *state, u_char *options, int opt_len,
                                         int unit, int hdrlen, int mru, int debug));
    static int      z_compress __P((void *state, struct mbuf **mret,
                                      struct mbuf *mp, int slen, int maxolen));
    static void     z_incomp __P((void *state, struct mbuf *dmsg));
    static int      z_decompress __P((void *state, struct mbuf *cmp,
                                        struct mbuf **dmpp));
    static void     z_comp_reset __P((void *state));
   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_comp_alloc,               /* comp_alloc */
       z_comp_free,                /* comp_free */
       z_comp_init,                /* comp_init */
       z_comp_reset,               /* comp_reset */
       z_compress,                 /* compress */
       z_comp_stats,               /* comp_stat */
       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 */
   };
   
   struct compressor ppp_deflate_draft = {
       CI_DEFLATE_DRAFT,           /* compress_proto */
       z_comp_alloc,               /* comp_alloc */
       z_comp_free,                /* comp_free */
       z_comp_init,                /* comp_init */
       z_comp_reset,               /* comp_reset */
       z_compress,                 /* compress */
       z_comp_stats,               /* comp_stat */
       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.
    */
   void *
   z_alloc(notused, items, size)
       void *notused;
       u_int items, size;
   {
       void *ptr;
   
       MALLOC(ptr, void *, items * size, M_DEVBUF, M_NOWAIT);
       return ptr;
   }
   
   void
   z_free(notused, ptr)
       void *notused;
       void *ptr;
   {
       FREE(ptr, M_DEVBUF);
   }
   
   /*
    * Allocate space for a compressor.
    */
   static void *
   z_comp_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[0] != CI_DEFLATE_DRAFT)
           || 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;
   
       MALLOC(state, struct deflate_state *, sizeof(struct deflate_state),
              M_DEVBUF, M_NOWAIT);
       if (state == NULL)
           return NULL;
   
       state->strm.next_in = NULL;
       state->strm.zalloc = z_alloc;
       state->strm.zfree = z_free;
       if (deflateInit2(&state->strm, Z_DEFAULT_COMPRESSION, DEFLATE_METHOD_VAL,
                        -w_size, 8, Z_DEFAULT_STRATEGY) != Z_OK) {
           FREE(state, M_DEVBUF);
           return NULL;
       }
   
       state->w_size = w_size;
       bzero(&state->stats, sizeof(state->stats));
       return (void *) state;
   }
   
   static void
   z_comp_free(arg)
       void *arg;
   {
       struct deflate_state *state = (struct deflate_state *) arg;
   
       deflateEnd(&state->strm);
       FREE(state, M_DEVBUF);
   }
   
   static int
   z_comp_init(arg, options, opt_len, unit, hdrlen, debug)
       void *arg;
       u_char *options;
       int opt_len, unit, hdrlen, debug;
   {
       struct deflate_state *state = (struct deflate_state *) arg;
   
       if (opt_len < CILEN_DEFLATE
           || (options[0] != CI_DEFLATE && options[0] != CI_DEFLATE_DRAFT)
           || 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;
   
       deflateReset(&state->strm);
   
       return 1;
   }
   
   static void
   z_comp_reset(arg)
       void *arg;
   {
       struct deflate_state *state = (struct deflate_state *) arg;
   
       state->seqno = 0;
       deflateReset(&state->strm);
   }
   
   int
   z_compress(arg, mret, mp, orig_len, maxolen)
       void *arg;
       struct mbuf **mret;         /* compressed packet (out) */
       struct mbuf *mp;            /* uncompressed packet (in) */
       int orig_len, maxolen;
   {
       struct deflate_state *state = (struct deflate_state *) arg;
       u_char *rptr, *wptr;
       int proto, olen, wspace, r, flush;
       struct mbuf *m;
   
       /*
        * Check that the protocol is in the range we handle.
        */
       rptr = mtod(mp, u_char *);
       proto = PPP_PROTOCOL(rptr);
       if (proto > 0x3fff || proto == 0xfd || proto == 0xfb) {
           *mret = NULL;
           return orig_len;
       }
   
       /* Allocate one mbuf initially. */
       if (maxolen > orig_len)
           maxolen = orig_len;
       MGET(m, M_DONTWAIT, MT_DATA);
       *mret = m;
       if (m != NULL) {
           m->m_len = 0;
           if (maxolen + state->hdrlen > MLEN)
               MCLGET(m, M_DONTWAIT);
           wspace = M_TRAILINGSPACE(m);
           if (state->hdrlen + PPP_HDRLEN + 2 < wspace) {
               m->m_data += state->hdrlen;
               wspace -= state->hdrlen;
           }
           wptr = mtod(m, u_char *);
   
           /*
            * Copy over the PPP header and store the 2-byte sequence number.
            */
           wptr[0] = PPP_ADDRESS(rptr);
           wptr[1] = PPP_CONTROL(rptr);
           wptr[2] = PPP_COMP >> 8;
           wptr[3] = PPP_COMP;
           wptr += PPP_HDRLEN;
           wptr[0] = state->seqno >> 8;
           wptr[1] = state->seqno;
           wptr += 2;
           state->strm.next_out = wptr;
           state->strm.avail_out = wspace - (PPP_HDRLEN + 2);
       } else {
           state->strm.next_out = NULL;
           state->strm.avail_out = 1000000;
           wptr = NULL;
           wspace = 0;
       }
       ++state->seqno;
   
       rptr += (proto > 0xff)? 2: 3;       /* skip 1st proto byte if 0 */
       state->strm.next_in = rptr;
       state->strm.avail_in = mtod(mp, u_char *) + mp->m_len - rptr;
       mp = mp->m_next;
       flush = (mp == NULL)? Z_PACKET_FLUSH: Z_NO_FLUSH;
       olen = 0;
       for (;;) {
           r = deflate(&state->strm, flush);
           if (r != Z_OK) {
               printf("z_compress: deflate returned %d (%s)\n",
                      r, (state->strm.msg? state->strm.msg: ""));
               break;
           }
           if (flush != Z_NO_FLUSH && state->strm.avail_out != 0)
               break;              /* all done */
           if (state->strm.avail_in == 0 && mp != NULL) {
               state->strm.next_in = mtod(mp, u_char *);
               state->strm.avail_in = mp->m_len;
               mp = mp->m_next;
               if (mp == NULL)
                   flush = Z_PACKET_FLUSH;
           }
           if (state->strm.avail_out == 0) {
               if (m != NULL) {
                   m->m_len = wspace;
                   olen += wspace;
                   MGET(m->m_next, M_DONTWAIT, MT_DATA);
                   m = m->m_next;
                   if (m != NULL) {
                       m->m_len = 0;
                       if (maxolen - olen > MLEN)
                           MCLGET(m, M_DONTWAIT);
                       state->strm.next_out = mtod(m, u_char *);
                       state->strm.avail_out = wspace = M_TRAILINGSPACE(m);
                   }
               }
               if (m == NULL) {
                   state->strm.next_out = NULL;
                   state->strm.avail_out = 1000000;
               }
           }
       }
       if (m != NULL)
           olen += (m->m_len = wspace - state->strm.avail_out);
   
       /*
        * See if we managed to reduce the size of the packet.
        */
       if (m != NULL && olen < orig_len) {
           state->stats.comp_bytes += olen;
           state->stats.comp_packets++;
       } else {
           if (*mret != NULL) {
               m_freem(*mret);
               *mret = NULL;
           }
           state->stats.inc_bytes += orig_len;
           state->stats.inc_packets++;
           olen = orig_len;
       }
       state->stats.unc_bytes += orig_len;
       state->stats.unc_packets++;
   
       return olen;
   }
   
   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->inc_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[0] != CI_DEFLATE_DRAFT)
           || 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;
   
       MALLOC(state, struct deflate_state *, sizeof(struct deflate_state),
              M_DEVBUF, M_NOWAIT);
       if (state == NULL)
           return NULL;
   
       state->strm.next_out = NULL;
       state->strm.zalloc = z_alloc;
       state->strm.zfree = z_free;
       if (inflateInit2(&state->strm, -w_size) != Z_OK) {
           FREE(state, M_DEVBUF);
           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, M_DEVBUF);
   }
   
   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[0] != CI_DEFLATE_DRAFT)
           || 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.
    */
   int
   z_decompress(arg, mi, mop)
       void *arg;
       struct mbuf *mi, **mop;
   {
       struct deflate_state *state = (struct deflate_state *) arg;
       struct mbuf *mo, *mo_head;
       u_char *rptr, *wptr;
       int rlen, olen, ospace;
       int seq, i, flush, r, decode_proto;
       u_char hdr[PPP_HDRLEN + DEFLATE_OVHD];
   
       *mop = NULL;
       rptr = mtod(mi, u_char *);
       rlen = mi->m_len;
       for (i = 0; i < PPP_HDRLEN + DEFLATE_OVHD; ++i) {
           while (rlen <= 0) {
               mi = mi->m_next;
               if (mi == NULL)
                   return DECOMP_ERROR;
               rptr = mtod(mi, u_char *);
               rlen = mi->m_len;
           }
           hdr[i] = *rptr++;
           --rlen;
       }
   
       /* Check the sequence number. */
       seq = (hdr[PPP_HDRLEN] << 8) + hdr[PPP_HDRLEN+1];
       if (seq != state->seqno) {
           if (state->debug)
               printf("z_decompress%d: bad seq # %d, expected %d\n",
                      state->unit, seq, state->seqno);
           return DECOMP_ERROR;
       }
       ++state->seqno;
   
       /* Allocate an output mbuf. */
       MGETHDR(mo, M_DONTWAIT, MT_DATA);
       if (mo == NULL)
           return DECOMP_ERROR;
       mo_head = mo;
       mo->m_len = 0;
       mo->m_next = NULL;
       MCLGET(mo, M_DONTWAIT);
       ospace = M_TRAILINGSPACE(mo);
       if (state->hdrlen + PPP_HDRLEN < ospace) {
           mo->m_data += state->hdrlen;
           ospace -= state->hdrlen;
       }
   
       /*
        * Fill in the first part of the PPP header.  The protocol field
        * comes from the decompressed data.
        */
       wptr = mtod(mo, u_char *);
       wptr[0] = PPP_ADDRESS(hdr);
       wptr[1] = PPP_CONTROL(hdr);
       wptr[2] = 0;
   
       /*
        * Set up to call inflate.  We set avail_out to 1 initially so we can
        * look at the first byte of the output and decide whether we have
        * a 1-byte or 2-byte protocol field.
        */
       state->strm.next_in = rptr;
       state->strm.avail_in = rlen;
       mi = mi->m_next;
       flush = (mi == NULL)? Z_PACKET_FLUSH: Z_NO_FLUSH;
       rlen += PPP_HDRLEN + DEFLATE_OVHD;
       state->strm.next_out = wptr + 3;
       state->strm.avail_out = 1;
       decode_proto = 1;
       olen = PPP_HDRLEN;
   
       /*
        * Call inflate, supplying more input or output as needed.
        */
       for (;;) {
           r = inflate(&state->strm, 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: ""));
               m_freem(mo_head);
               return DECOMP_FATALERROR;
           }
           if (flush != Z_NO_FLUSH && state->strm.avail_out != 0)
               break;              /* all done */
           if (state->strm.avail_in == 0 && mi != NULL) {
               state->strm.next_in = mtod(mi, u_char *);
               state->strm.avail_in = mi->m_len;
               rlen += mi->m_len;
               mi = mi->m_next;
               if (mi == NULL)
                   flush = Z_PACKET_FLUSH;
           }
           if (state->strm.avail_out == 0) {
               if (decode_proto) {
                   state->strm.avail_out = ospace - PPP_HDRLEN;
                   if ((wptr[3] & 1) == 0) {
                       /* 2-byte protocol field */
                       wptr[2] = wptr[3];
                       --state->strm.next_out;
                       ++state->strm.avail_out;
                       --olen;
                   }
                   decode_proto = 0;
               } else {
                   mo->m_len = ospace;
                   olen += ospace;
                   MGET(mo->m_next, M_DONTWAIT, MT_DATA);
                   mo = mo->m_next;
                   if (mo == NULL) {
                       m_freem(mo_head);
                       return DECOMP_ERROR;
                   }
                   MCLGET(mo, M_DONTWAIT);
                   state->strm.next_out = mtod(mo, u_char *);
                   state->strm.avail_out = ospace = M_TRAILINGSPACE(mo);
               }
           }
       }
       if (decode_proto) {
           m_freem(mo_head);
           return DECOMP_ERROR;
       }
       olen += (mo->m_len = ospace - state->strm.avail_out);
   #if DEFLATE_DEBUG
       if (state->debug && 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++;
   
       *mop = mo_head;
       return DECOMP_OK;
   }
   
   /*
    * Incompressible data has arrived - add it to the history.
    */
   static void
   z_incomp(arg, mi)
       void *arg;
       struct mbuf *mi;
   {
       struct deflate_state *state = (struct deflate_state *) arg;
       u_char *rptr;
       int rlen, proto, r;
   
       /*
        * Check that the protocol is one we handle.
        */
       rptr = mtod(mi, u_char *);
       proto = PPP_PROTOCOL(rptr);
       if (proto > 0x3fff || proto == 0xfd || proto == 0xfb)
           return;
   
       ++state->seqno;
   
       /*
        * Iterate through the mbufs, adding the characters in them
        * to the decompressor's history.  For the first mbuf, we start
        * at the either the 1st or 2nd byte of the protocol field,
        * depending on whether the protocol value is compressible.
        */
       rlen = mi->m_len;
       state->strm.next_in = rptr + 3;
       state->strm.avail_in = rlen - 3;
       if (proto > 0xff) {
           --state->strm.next_in;
           ++state->strm.avail_in;
       }
       for (;;) {
           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;
           }
           mi = mi->m_next;
           if (mi == NULL)
               break;
           state->strm.next_in = mtod(mi, u_char *);
           state->strm.avail_in = mi->m_len;
           rlen += mi->m_len;
       }
   
       /*
        * Update stats.
        */
       state->stats.inc_bytes += rlen;
       state->stats.inc_packets++;
       state->stats.unc_bytes += rlen;
       state->stats.unc_packets++;
   }
   
   #endif /* DO_DEFLATE */

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