git.distorted.org.uk Git - u/mdw/catacomb/blob - buf.h

   1 /* -*-c-*-
   2  *
   3  * $Id: buf.h,v 1.4 2004/04/08 01:36:15 mdw Exp $
   4  *
   5  * Reading and writing packet buffers
   6  *
   7  * (c) 2001 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of Catacomb.
  13  *
  14  * Catacomb is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU Library General Public License as
  16  * published by the Free Software Foundation; either version 2 of the
  17  * License, or (at your option) any later version.
  18  *
  19  * Catacomb is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU Library General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU Library General Public
  25  * License along with Catacomb; if not, write to the Free
  26  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  27  * MA 02111-1307, USA.
  28  */
  29
  30 #ifndef CATACOMB_BUF_H
  31 #define CATACOMB_BUF_H
  32
  33 #ifdef __cplusplus
  34   extern "C" {
  35 #endif
  36
  37 /*----- Header files ------------------------------------------------------*/
  38
  39 #include <stddef.h>
  40
  41 #include <mLib/bits.h>
  42
  43 #ifndef CATACOMB_MP_H
  44 #  include "mp.h"
  45 #endif
  46
  47 #ifndef CATACOMB_EC_H
  48 #  include "ec.h"
  49 #endif
  50
  51 /*----- Data structures ---------------------------------------------------*/
  52
  53 /* --- Buffers --- *
  54  *
  55  * Buffers provide a simple stream-like interface for building and parsing
  56  * packets.
  57  */
  58
  59 typedef struct buf {
  60   octet *base, *p, *limit;              /* Pointers to the buffer */
  61   unsigned f;                           /* Various flags */
  62 } buf;
  63
  64 #define BF_BROKEN 1u                    /* Buffer is broken */
  65
  66 /*----- Useful macros -----------------------------------------------------*/
  67
  68 #define BBASE(b) ((b)->base)
  69 #define BLIM(b) ((b)->limit)
  70 #define BCUR(b) ((b)->p)
  71 #define BSZ(b) ((b)->limit - (b)->base)
  72 #define BLEN(b) ((b)->p - (b)->base)
  73 #define BLEFT(b) ((b)->limit - (b)->p)
  74 #define BSTEP(b, sz) ((b)->p += (sz))
  75 #define BBAD(b) ((b)->f & BF_BROKEN)
  76 #define BOK(b) (!BBAD(b))
  77
  78 #define BENSURE(b, sz)                                                  \
  79   (BBAD(b) ? -1 : (sz) > BLEFT(b) ? (b)->f |= BF_BROKEN, -1 : 0)
  80
  81 /*----- Functions provided ------------------------------------------------*/
  82
  83 /* --- @buf_init@ --- *
  84  *
  85  * Arguments:   @buf *b@ = pointer to a buffer block
  86  *              @void *p@ = pointer to a buffer
  87  *              @size_t sz@ = size of the buffer
  88  *
  89  * Returns:     ---
  90  *
  91  * Use:         Initializes the buffer block appropriately.
  92  */
  93
  94 extern void buf_init(buf */*b*/, void */*p*/, size_t /*sz*/);
  95
  96 /* --- @buf_break@ --- *
  97  *
  98  * Arguments:   @buf *b@ = pointer to a buffer block
  99  *
 100  * Returns:     Some negative value.
 101  *
 102  * Use:         Marks a buffer as broken.
 103  */
 104
 105 extern int buf_break(buf */*b*/);
 106
 107 /* --- @buf_flip@ --- *
 108  *
 109  * Arguments:   @buf *b@ = pointer to a buffer block
 110  *
 111  * Returns:     ---
 112  *
 113  * Use:         Flips a buffer so that if you've just been writing to it,
 114  *              you can now read from the bit you've written.
 115  */
 116
 117 extern void buf_flip(buf */*b*/);
 118
 119 /* --- @buf_ensure@ --- *
 120  *
 121  * Arguments:   @buf *b@ = pointer to a buffer block
 122  *              @size_t sz@ = size of data wanted
 123  *
 124  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 125  *
 126  * Use:         Ensures that there are @sz@ bytes still in the buffer.
 127  */
 128
 129 extern int buf_ensure(buf */*b*/, size_t /*sz*/);
 130
 131 /* --- @buf_get@ --- *
 132  *
 133  * Arguments:   @buf *b@ = pointer to a buffer block
 134  *              @size_t sz@ = size of the buffer
 135  *
 136  * Returns:     Pointer to the place in the buffer.
 137  *
 138  * Use:         Reserves a space in the buffer of the requested size, and
 139  *              returns its start address.
 140  */
 141
 142 extern void *buf_get(buf */*b*/, size_t /*sz*/);
 143
 144 /* --- @buf_put@ --- *
 145  *
 146  * Arguments:   @buf *b@ = pointer to a buffer block
 147  *              @const void *p@ = pointer to a buffer
 148  *              @size_t sz@ = size of the buffer
 149  *
 150  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 151  *
 152  * Use:         Fetches data from some place and puts it in the buffer
 153  */
 154
 155 extern int buf_put(buf */*b*/, const void */*p*/, size_t /*sz*/);
 156
 157 /* --- @buf_getbyte@ --- *
 158  *
 159  * Arguments:   @buf *b@ = pointer to a buffer block
 160  *
 161  * Returns:     A byte, or less than zero if there wasn't a byte there.
 162  *
 163  * Use:         Gets a single byte from a buffer.
 164  */
 165
 166 extern int buf_getbyte(buf */*b*/);
 167
 168 /* --- @buf_putbyte@ --- *
 169  *
 170  * Arguments:   @buf *b@ = pointer to a buffer block
 171  *              @int ch@ = byte to write
 172  *
 173  * Returns:     Zero if OK, nonzero if there wasn't enough space.
 174  *
 175  * Use:         Puts a single byte in a buffer.
 176  */
 177
 178 extern int buf_putbyte(buf */*b*/, int /*ch*/);
 179
 180 /* --- @buf_getu16@ --- *
 181  *
 182  * Arguments:   @buf *b@ = pointer to a buffer block
 183  *              @uint16 *w@ = where to put the word
 184  *
 185  * Returns:     Zero if OK, or nonzero if there wasn't a word there.
 186  *
 187  * Use:         Gets a 16-bit word from a buffer.
 188  */
 189
 190 extern int buf_getu16(buf */*b*/, uint16 */*w*/);
 191
 192 /* --- @buf_putu16@ --- *
 193  *
 194  * Arguments:   @buf *b@ = pointer to a buffer block
 195  *              @uint16 w@ = word to write
 196  *
 197  * Returns:     Zero if OK, nonzero if there wasn't enough space.
 198  *
 199  * Use:         Puts a 16-but word in a buffer.
 200  */
 201
 202 extern int buf_putu16(buf */*b*/, uint16 /*w*/);
 203
 204 /* --- @buf_getu32@ --- *
 205  *
 206  * Arguments:   @buf *b@ = pointer to a buffer block
 207  *              @uint32 *w@ = where to put the word
 208  *
 209  * Returns:     Zero if OK, or nonzero if there wasn't a word there.
 210  *
 211  * Use:         Gets a 32-bit word from a buffer.
 212  */
 213
 214 extern int buf_getu32(buf */*b*/, uint32 */*w*/);
 215
 216 /* --- @buf_putu32@ --- *
 217  *
 218  * Arguments:   @buf *b@ = pointer to a buffer block
 219  *              @uint32 w@ = word to write
 220  *
 221  * Returns:     Zero if OK, nonzero if there wasn't enough space.
 222  *
 223  * Use:         Puts a 32-but word in a buffer.
 224  */
 225
 226 extern int buf_putu32(buf */*b*/, uint32 /*w*/);
 227
 228 /* --- @buf_getmp@ --- *
 229  *
 230  * Arguments:   @buf *b@ = pointer to a buffer block
 231  *
 232  * Returns:     A multiprecision integer, or null if there wasn't one there.
 233  *
 234  * Use:         Gets a multiprecision integer from a buffer.
 235  */
 236
 237 extern mp *buf_getmp(buf */*b*/);
 238
 239 /* --- @buf_putmp@ --- *
 240  *
 241  * Arguments:   @buf *b@ = pointer to a buffer block
 242  *              @mp *m@ = a multiprecision integer
 243  *
 244  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 245  *
 246  * Use:         Puts a multiprecision integer to a buffer.
 247  */
 248
 249 extern int buf_putmp(buf */*b*/, mp */*m*/);
 250
 251 /* --- @buf_getec@ --- *
 252  *
 253  * Arguments:   @buf *b@ = pointer to a buffer block
 254  *              @ec *p@ = where to put the point
 255  *
 256  * Returns:     Zero if it worked, nonzero if it failed.
 257  *
 258  * Use:         Gets a multiprecision integer from a buffer.  The point must
 259  *              be initialized.
 260  */
 261
 262 extern int buf_getec(buf */*b*/, ec */*p*/);
 263
 264 /* --- @buf_putec@ --- *
 265  *
 266  * Arguments:   @buf *b@ = pointer to a buffer block
 267  *              @ec *p@ = an elliptic curve point
 268  *
 269  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 270  *
 271  * Use:         Puts an elliptic curve point to a buffer.
 272  */
 273
 274 extern int buf_putec(buf */*b*/, ec */*p*/);
 275
 276 /*----- That's all, folks -------------------------------------------------*/
 277
 278 #ifdef __cplusplus
 279   }
 280 #endif
 281
 282 #endif