release/src/router/openvpn/lzo.h

   1 /*
   2  *  OpenVPN -- An application to securely tunnel IP networks
   3  *             over a single UDP port, with support for SSL/TLS-based
   4  *             session authentication and key exchange,
   5  *             packet encryption, packet authentication, and
   6  *             packet compression.
   7  *
   8  *  Copyright (C) 2002-2009 OpenVPN Technologies, Inc. <sales@openvpn.net>
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License version 2
  12  *  as published by the Free Software Foundation.
  13  *
  14  *  This program is distributed in the hope that it will be useful,
  15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *  GNU General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License
  20  *  along with this program (see the file COPYING included with this
  21  *  distribution); if not, write to the Free Software Foundation, Inc.,
  22  *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  */
  24
  25 #ifndef OPENVPN_LZO_H
  26 #define OPENVPN_LZO_H
  27
  28 #ifdef USE_LZO
  29
  30 #ifdef LZO_HEADER_DIR
  31 #include "lzo/lzoutil.h"
  32 #include "lzo/lzo1x.h"
  33 #else
  34 #include "lzoutil.h"
  35 #include "lzo1x.h"
  36 #endif
  37
  38 #include "buffer.h"
  39 #include "mtu.h"
  40 #include "common.h"
  41 #include "status.h"
  42
  43 /* LZO flags */
  44 #define LZO_SELECTED   (1<<0)
  45 #define LZO_ON         (1<<1)
  46 #define LZO_ADAPTIVE   (1<<2)
  47
  48 /*
  49  * Use LZO compress routine lzo1x_1_15_compress which is described
  50  * as faster but needs a bit more memory than the standard routine.
  51  * Use safe decompress (i.e. check for buffer overflows).
  52  * You may want to use the non-safe version
  53  * of decompress if speed is essential and if you know
  54  * that you will always be using a MAC to verify the
  55  * integrity of incoming packets.
  56  */
  57 #define LZO_COMPRESS    lzo1x_1_15_compress
  58 #define LZO_WORKSPACE   LZO1X_1_15_MEM_COMPRESS
  59 #define LZO_DECOMPRESS  lzo1x_decompress_safe
  60
  61 #define LZO_EXTRA_BUFFER(len) ((len)/8 + 128 + 3)       /* LZO 2.0 worst case size expansion. */
  62
  63 /*
  64  * Don't try to compress any packet smaller than this.
  65  */
  66 #define COMPRESS_THRESHOLD 100
  67
  68 /*
  69  * Length of prepended prefix on LZO packets
  70  */
  71 #define LZO_PREFIX_LEN 1
  72
  73 /*
  74  * Adaptive compress parameters
  75  */
  76 #define AC_SAMP_SEC    2      /* number of seconds in sample period */
  77 #define AC_MIN_BYTES   1000   /* sample period must have at least n bytes
  78                                  to be valid for testing */
  79 #define AC_SAVE_PCT    5      /* turn off compress if we didn't save at
  80                                  least this % during sample period */
  81 #define AC_OFF_SEC     60     /* if we turn off compression, don't do sample
  82                                  retest for n seconds */
  83
  84 struct lzo_adaptive_compress {
  85   bool compress_state;
  86   time_t next;
  87   int n_total;
  88   int n_comp;
  89 };
  90
  91 /*
  92  * Compress and Uncompress routines.
  93  */
  94
  95 struct lzo_compress_workspace
  96 {
  97   lzo_voidp wmem;
  98   int wmem_size;
  99   struct lzo_adaptive_compress ac;
 100   unsigned int flags;
 101   bool defined;
 102
 103   /* statistics */
 104   counter_type pre_decompress;
 105   counter_type post_decompress;
 106   counter_type pre_compress;
 107   counter_type post_compress;
 108 };
 109
 110 void lzo_adjust_frame_parameters(struct frame *frame);
 111
 112 void lzo_compress_init (struct lzo_compress_workspace *lzowork, unsigned int flags);
 113
 114 void lzo_compress_uninit (struct lzo_compress_workspace *lzowork);
 115
 116 void lzo_modify_flags (struct lzo_compress_workspace *lzowork, unsigned int flags);
 117
 118 void lzo_compress (struct buffer *buf, struct buffer work,
 119                    struct lzo_compress_workspace *lzowork,
 120                    const struct frame* frame);
 121
 122 void lzo_decompress (struct buffer *buf, struct buffer work,
 123                      struct lzo_compress_workspace *lzowork,
 124                      const struct frame* frame);
 125
 126 void lzo_print_stats (const struct lzo_compress_workspace *lzo_compwork, struct status_output *so);
 127
 128 static inline bool
 129 lzo_defined (const struct lzo_compress_workspace *lzowork)
 130 {
 131   return lzowork->defined;
 132 }
 133
 134
 135 #endif /* USE_LZO */
 136 #endif