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

   1 /* -*-c-*-
   2  *
   3  * $Id: buf.h,v 1.3 2004/04/01 12:50:09 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 /*----- Revision history --------------------------------------------------*
  31  *
  32  * $Log: buf.h,v $
  33  * Revision 1.3  2004/04/01 12:50:09  mdw
  34  * Add cyclic group abstraction, with test code.  Separate off exponentation
  35  * functions for better static linking.  Fix a buttload of bugs on the way.
  36  * Generally ensure that negative exponents do inversion correctly.  Add
  37  * table of standard prime-field subgroups.  (Binary field subgroups are
  38  * currently unimplemented but easy to add if anyone ever finds a good one.)
  39  *
  40  * Revision 1.2  2003/11/10 22:18:30  mdw
  41  * Build fixes.
  42  *
  43  * Revision 1.1  2003/10/11 21:02:33  mdw
  44  * Import buf stuff from tripe.
  45  *
  46  * Revision 1.1  2001/06/19 22:09:54  mdw
  47  * Expose interface, for use in the proxy.
  48  *
  49  */
  50
  51 #ifndef CATACOMB_BUF_H
  52 #define CATACOMB_BUF_H
  53
  54 #ifdef __cplusplus
  55   extern "C" {
  56 #endif
  57
  58 /*----- Header files ------------------------------------------------------*/
  59
  60 #include <stddef.h>
  61
  62 #include <mLib/bits.h>
  63
  64 #ifndef CATACOMB_MP_H
  65 #  include "mp.h"
  66 #endif
  67
  68 #ifndef CATACOMB_EC_H
  69 #  include "ec.h"
  70 #endif
  71
  72 /*----- Data structures ---------------------------------------------------*/
  73
  74 /* --- Buffers --- *
  75  *
  76  * Buffers provide a simple stream-like interface for building and parsing
  77  * packets.
  78  */
  79
  80 typedef struct buf {
  81   octet *base, *p, *limit;              /* Pointers to the buffer */
  82   unsigned f;                           /* Various flags */
  83 } buf;
  84
  85 #define BF_BROKEN 1u                    /* Buffer is broken */
  86
  87 /*----- Useful macros -----------------------------------------------------*/
  88
  89 #define BBASE(b) ((b)->base)
  90 #define BLIM(b) ((b)->limit)
  91 #define BCUR(b) ((b)->p)
  92 #define BSZ(b) ((b)->limit - (b)->base)
  93 #define BLEN(b) ((b)->p - (b)->base)
  94 #define BLEFT(b) ((b)->limit - (b)->p)
  95 #define BSTEP(b, sz) ((b)->p += (sz))
  96 #define BBAD(b) ((b)->f & BF_BROKEN)
  97 #define BOK(b) (!BBAD(b))
  98
  99 #define BENSURE(b, sz)                                                  \
 100   (BBAD(b) ? -1 : (sz) > BLEFT(b) ? (b)->f |= BF_BROKEN, -1 : 0)
 101
 102 /*----- Functions provided ------------------------------------------------*/
 103
 104 /* --- @buf_init@ --- *
 105  *
 106  * Arguments:   @buf *b@ = pointer to a buffer block
 107  *              @void *p@ = pointer to a buffer
 108  *              @size_t sz@ = size of the buffer
 109  *
 110  * Returns:     ---
 111  *
 112  * Use:         Initializes the buffer block appropriately.
 113  */
 114
 115 extern void buf_init(buf */*b*/, void */*p*/, size_t /*sz*/);
 116
 117 /* --- @buf_break@ --- *
 118  *
 119  * Arguments:   @buf *b@ = pointer to a buffer block
 120  *
 121  * Returns:     Some negative value.
 122  *
 123  * Use:         Marks a buffer as broken.
 124  */
 125
 126 extern int buf_break(buf */*b*/);
 127
 128 /* --- @buf_flip@ --- *
 129  *
 130  * Arguments:   @buf *b@ = pointer to a buffer block
 131  *
 132  * Returns:     ---
 133  *
 134  * Use:         Flips a buffer so that if you've just been writing to it,
 135  *              you can now read from the bit you've written.
 136  */
 137
 138 extern void buf_flip(buf */*b*/);
 139
 140 /* --- @buf_ensure@ --- *
 141  *
 142  * Arguments:   @buf *b@ = pointer to a buffer block
 143  *              @size_t sz@ = size of data wanted
 144  *
 145  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 146  *
 147  * Use:         Ensures that there are @sz@ bytes still in the buffer.
 148  */
 149
 150 extern int buf_ensure(buf */*b*/, size_t /*sz*/);
 151
 152 /* --- @buf_get@ --- *
 153  *
 154  * Arguments:   @buf *b@ = pointer to a buffer block
 155  *              @size_t sz@ = size of the buffer
 156  *
 157  * Returns:     Pointer to the place in the buffer.
 158  *
 159  * Use:         Reserves a space in the buffer of the requested size, and
 160  *              returns its start address.
 161  */
 162
 163 extern void *buf_get(buf */*b*/, size_t /*sz*/);
 164
 165 /* --- @buf_put@ --- *
 166  *
 167  * Arguments:   @buf *b@ = pointer to a buffer block
 168  *              @const void *p@ = pointer to a buffer
 169  *              @size_t sz@ = size of the buffer
 170  *
 171  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 172  *
 173  * Use:         Fetches data from some place and puts it in the buffer
 174  */
 175
 176 extern int buf_put(buf */*b*/, const void */*p*/, size_t /*sz*/);
 177
 178 /* --- @buf_getbyte@ --- *
 179  *
 180  * Arguments:   @buf *b@ = pointer to a buffer block
 181  *
 182  * Returns:     A byte, or less than zero if there wasn't a byte there.
 183  *
 184  * Use:         Gets a single byte from a buffer.
 185  */
 186
 187 extern int buf_getbyte(buf */*b*/);
 188
 189 /* --- @buf_putbyte@ --- *
 190  *
 191  * Arguments:   @buf *b@ = pointer to a buffer block
 192  *              @int ch@ = byte to write
 193  *
 194  * Returns:     Zero if OK, nonzero if there wasn't enough space.
 195  *
 196  * Use:         Puts a single byte in a buffer.
 197  */
 198
 199 extern int buf_putbyte(buf */*b*/, int /*ch*/);
 200
 201 /* --- @buf_getu16@ --- *
 202  *
 203  * Arguments:   @buf *b@ = pointer to a buffer block
 204  *              @uint16 *w@ = where to put the word
 205  *
 206  * Returns:     Zero if OK, or nonzero if there wasn't a word there.
 207  *
 208  * Use:         Gets a 16-bit word from a buffer.
 209  */
 210
 211 extern int buf_getu16(buf */*b*/, uint16 */*w*/);
 212
 213 /* --- @buf_putu16@ --- *
 214  *
 215  * Arguments:   @buf *b@ = pointer to a buffer block
 216  *              @uint16 w@ = word to write
 217  *
 218  * Returns:     Zero if OK, nonzero if there wasn't enough space.
 219  *
 220  * Use:         Puts a 16-but word in a buffer.
 221  */
 222
 223 extern int buf_putu16(buf */*b*/, uint16 /*w*/);
 224
 225 /* --- @buf_getu32@ --- *
 226  *
 227  * Arguments:   @buf *b@ = pointer to a buffer block
 228  *              @uint32 *w@ = where to put the word
 229  *
 230  * Returns:     Zero if OK, or nonzero if there wasn't a word there.
 231  *
 232  * Use:         Gets a 32-bit word from a buffer.
 233  */
 234
 235 extern int buf_getu32(buf */*b*/, uint32 */*w*/);
 236
 237 /* --- @buf_putu32@ --- *
 238  *
 239  * Arguments:   @buf *b@ = pointer to a buffer block
 240  *              @uint32 w@ = word to write
 241  *
 242  * Returns:     Zero if OK, nonzero if there wasn't enough space.
 243  *
 244  * Use:         Puts a 32-but word in a buffer.
 245  */
 246
 247 extern int buf_putu32(buf */*b*/, uint32 /*w*/);
 248
 249 /* --- @buf_getmp@ --- *
 250  *
 251  * Arguments:   @buf *b@ = pointer to a buffer block
 252  *
 253  * Returns:     A multiprecision integer, or null if there wasn't one there.
 254  *
 255  * Use:         Gets a multiprecision integer from a buffer.
 256  */
 257
 258 extern mp *buf_getmp(buf */*b*/);
 259
 260 /* --- @buf_putmp@ --- *
 261  *
 262  * Arguments:   @buf *b@ = pointer to a buffer block
 263  *              @mp *m@ = a multiprecision integer
 264  *
 265  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 266  *
 267  * Use:         Puts a multiprecision integer to a buffer.
 268  */
 269
 270 extern int buf_putmp(buf */*b*/, mp */*m*/);
 271
 272 /* --- @buf_getec@ --- *
 273  *
 274  * Arguments:   @buf *b@ = pointer to a buffer block
 275  *              @ec *p@ = where to put the point
 276  *
 277  * Returns:     Zero if it worked, nonzero if it failed.
 278  *
 279  * Use:         Gets a multiprecision integer from a buffer.  The point must
 280  *              be initialized.
 281  */
 282
 283 extern int buf_getec(buf */*b*/, ec */*p*/);
 284
 285 /* --- @buf_putec@ --- *
 286  *
 287  * Arguments:   @buf *b@ = pointer to a buffer block
 288  *              @ec *p@ = an elliptic curve point
 289  *
 290  * Returns:     Zero if it worked, nonzero if there wasn't enough space.
 291  *
 292  * Use:         Puts an elliptic curve point to a buffer.
 293  */
 294
 295 extern int buf_putec(buf */*b*/, ec */*p*/);
 296
 297 /*----- That's all, folks -------------------------------------------------*/
 298
 299 #ifdef __cplusplus
 300   }
 301 #endif
 302
 303 #endif