plugins/wimax/wimax_bits.h

   1 /* wimax_bits.h
   2  * WiMax MAC Management UL-MAP Message decoder
   3  *
   4  * Copyright (c) 2007 by Intel Corporation.
   5  *
   6  * Author: Mike Harvey <michael.harvey@intel.com>
   7  *
   8  * $Id$
   9  *
  10  * Wireshark - Network traffic analyzer
  11  * By Gerald Combs <gerald@wireshark.org>
  12  * Copyright 1999 Gerald Combs
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License
  16  * as published by the Free Software Foundation; either version 2
  17  * of the License, or (at your option) any later version.
  18  *
  19  * This program 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 General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, write to the Free Software
  26  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  27  */
  28
  29 #ifndef __wimax_bits_h__
  30 #define __wimax_bits_h__
  31
  32 #include <wsutil/pint.h>
  33
  34 /********************************************************************
  35  * Functions for working with nibbles and bits
  36  */
  37
  38 /* SWAR functions */
  39 #define _BITS(n,hi,lo) (((n)>>(lo))&((1<<(((hi)-(lo))+1))-1))
  40 #define _ADD_SWAP(x,y) { (x) = (x) + (y); (y) = (x) - (y); (x) = (x) - (y); }
  41 #define _XOR_SWAP(x,y) { (x) ^= (y); (y) ^= (x); (x) ^= (y); }
  42 #define _SWAP(x,y) do { int t = (x); (x) = (y); (y) = t; } while(0)
  43
  44
  45 /********************************************************************
  46  * Functions for working with nibbles
  47  *
  48  */
  49
  50 #define NIBBLE_MASK 0x0F
  51 #define BYTE_MASK 0xFF
  52
  53 /* extract the nibble at the given nibble address 'n' of buffer 'b' */
  54 #define NIB_NIBBLE(n,b) \
  55     (((n) & 1) \
  56     ?  (b)[(n)/2] & NIBBLE_MASK \
  57     : ((b)[(n)/2] >> 4) & NIBBLE_MASK)
  58
  59 /* extract the byte at the given nibble address 'n' of buffer 'b' */
  60 #define NIB_BYTE(n,b) \
  61     (n) & 1 \
  62     ? (pntohs( (b)+(n)/2 ) >> 4) & BYTE_MASK \
  63     : (b)[(n)/2]
  64     /*
  65     ? (pletohs((b)+(n)/2) >> 4) & BYTE_MASK \
  66     */
  67
  68 /* extract 12 bits at the given nibble address */
  69 #define NIB_BITS12(n,b) \
  70       (NIB_NIBBLE(n,b+1) | (NIB_BYTE(n,b) << 4))
  71
  72 /* extract the word at the given nibble address 'n' of buffer 'b' */
  73 #define NIB_WORD(n,b) \
  74     (n) & 1 \
  75     ? (gint)((pntohl(((b) + (n)/2)) >> 12) & 0x0000FFFF) \
  76     : pntohs((b) + (n)/2)
  77     /*
  78     : pletohs((b) + (n)/2)
  79     ? (pletohl((b)+(n)/2) >> 12) & 0x0000FFFF \
  80     */
  81
  82 /* extract the word at the given nibble address 'n' of buffer 'b' */
  83 #define NIB_LONG(n,b) \
  84     (n) & 1 \
  85     ? (pntohl(((b) + (n)/2)) << 4) | (((b)[(n)/2 + 4] >> 4) & NIBBLE_MASK) \
  86     : pntohl((b) + (n)/2)
  87     /*
  88     ? (pletohl((b) + (n)/2) << 4) | (((b)[(n)/2 + 4] >> 4) & NIBBLE_MASK) \
  89     : pletohl((b) + (n)/2)
  90     */
  91
  92 /* Only currently used with nib == 1 or 2 */
  93 #define NIB_NIBS(nib, buf, num) \
  94     ((num) == 1 ? NIB_NIBBLE(nib,buf) : \
  95     ((num) == 2 ? NIB_BYTE(nib,buf) : \
  96     ((num) == 3 ? NIB_BITS12(nib,buf) : \
  97     ((num) == 4 ? NIB_WORD(nib,buf) : \
  98     0))))
  99
 100
 101 /* to highlight nibfields correctly in wireshark
 102  * AddItem(..., WSADDR(buf,bit), WSLEN(bit), ...) */
 103
 104 /* determine starting byte to highlight a series of nibbles */
 105 #define NIB_ADDR(nib) ((nib)/2)
 106 /* determine number of bytes to highlight a series of nibbles */
 107 #define NIB_LEN(nib,len)   ((1 +  ((nib)   &1) + (len))/2)
 108
 109 #define NIBHI(nib,len)  NIB_ADDR(nib),NIB_LEN(nib,len)
 110
 111 /********************************************************************
 112  * bitfield functions - for extracting bitfields from a buffer
 113  *
 114  * TODO: 64 bit functions use two 32-bit values;
 115  * would be better to use 32+8 bits to avoid overrunning buffers
 116  *
 117  */
 118
 119 /* find the byte-address for the bitfield */
 120 #define ADDR(bit)   ((bit) / 8)
 121 #define ADDR16(bit) ((bit) / 8)
 122 #define ADDR32(bit) ((bit) / 8)
 123
 124 /* find the offset (from the MSB) to the start of the bitfield */
 125 #define OFFSET(bit)    ((bit) % 8)
 126 #define OFFSET16(bit)  ((bit) % 8)
 127 #define OFFSET32(bit)  ((bit) % 8)
 128
 129 /* find the number of bits to shift right (SHIFT64 is upper dword) */
 130 #define SHIFT(bit,num)    ( 8 - ((bit)%8) - (num))
 131 #define SHIFT16(bit,num)  (16 - ((bit)%8) - (num))
 132 #define SHIFT32(bit,num)  (32 - ((bit)%8) - (num))
 133 #define SHIFT64a(bit,num) (num - (32 - OFFSET32(bit)))
 134 #define SHIFT64b(bit,num) (32 - ((num) - (32 - OFFSET32(bit))))
 135
 136 /* create a mask to mask off the bitfield */
 137 #define MASK8(num)       (0xFF >> (8 - (num)))
 138 #define MASK16(num)      (0xFFFF >> (16 - (num)))
 139 #define MASK32(num)      (0xFFFFFFFF >> (32 - (num)))
 140 #define MASK64a(bit)     (MASK32(32 - OFFSET32(bit)))
 141 #define MASK64b(bit,num) (MASK32(num - (32 - OFFSET32(bit))))
 142
 143 /* note that if you have a bitfield of length 2 or more, it may cross a
 144  * byte boundary so you should use BIT_BITS16 */
 145
 146 /* extract a single bit
 147  * bit ... bit address
 148  * buf ... buffer
 149  */
 150 #define BIT_BIT(bit, buf) \
 151     (( (buf)[ADDR(bit)] >> SHIFT(bit,1) ) & 0x1)
 152
 153 /* extract bitfield up to 9 bits
 154  * bit ... bit address
 155  * buf ... buffer
 156  * num ... length of bitfield
 157  */
 158 #define BIT_BITS16(bit, buf, num) \
 159     (( pntohs(buf+ADDR16(bit)) >> SHIFT16(bit,num) ) & MASK16(num))
 160
 161 /* extract bitfield up to 24 bits
 162  * bit ... bit address
 163  * buf ... buffer
 164  * num ... length of bitfield
 165  */
 166
 167 #define BIT_BITS32(bit, buf, num) \
 168       ((pntohl(buf+ADDR32(bit)) >> SHIFT32(bit,num) ) & MASK32(num))
 169
 170 /* bitfield up to 32 bits */
 171 #define BIT_BITS64a(bit, buf, num) \
 172       ((pntohl(buf+ADDR32(bit)) & MASK64a(bit)) << SHIFT64a(bit,num))
 173
 174 #define BIT_BITS64b(bit, buf, num) \
 175       ((pntohl(buf+ADDR32(bit)+4) >> SHIFT64b(bit,num) ) & MASK64b(bit,num))
 176
 177 #define BIT_BITS64(bit, buf, num) \
 178       ( (OFFSET32(bit)+(num)) <= 32 \
 179       ? BIT_BITS32(bit,buf,num) \
 180       : BIT_BITS64a(bit,buf,num) \
 181       | BIT_BITS64b(bit,buf,num) )
 182
 183 #define BIT_BITS(bit, buf, num) \
 184     ((num) ==  1 ? (gint)BIT_BIT(bit,buf) : \
 185     ((num) <=  9 ? (gint)BIT_BITS16(bit,buf,num) : \
 186     ((num) <= 24 ? (gint)BIT_BITS32(bit,buf,num) : \
 187     ((num) <= 32 ? (gint)BIT_BITS64(bit,buf,num) : \
 188                    (gint)0 ))))
 189
 190 /* to highlight bitfields correctly in wireshark
 191  * AddItem(..., WSADDR(buf,bit), WSLEN(bit), ...) */
 192
 193 /* determine starting byte to highlight a series of nibbles */
 194 #define BIT_ADDR(bit) (ADDR(bit))
 195 /* determine number of bytes to highlight */
 196 #define BIT_LEN(bit,len) (1 + ((OFFSET(bit) + len - 1) / 8))
 197
 198 #define BITHI(bit,len)  BIT_ADDR(bit),BIT_LEN(bit,len)
 199
 200 /* CONVENIENCE FUNCTIONS */
 201
 202 #define BIT_NIBBLE(bit,buf) BIT_BITS16(bit,buf,4)
 203 #define BIT_BYTE(bit,buf) BIT_BITS16(bit,buf,8)
 204 #define BIT_WORD(bit,buf) BIT_BITS32(bit,buf,16)
 205 #define BIT_WORD24(bit,buf) BIT_BITS32(bit,buf,24)
 206 #define BIT_LONG(bit,buf) BIT_BITS64(bit,buf,32)
 207
 208 /********************************************************************
 209  * padding functions - return number of nibbles/bits needed to
 210  * pad to a byte boundary */
 211
 212 #define BIT_PADDING(bit, bits) ((bit) % (bits)) ? ((bits) - ((bit) % (bits))) : 0
 213 #define NIB_PADDING(nib) ((nib) & 0x1)
 214
 215 /********************************************************************
 216  * conversion functions - between bytes, nibbles, and bits */
 217
 218 #define BYTE_TO_BIT(n)  ((n) * 8)
 219 #define BYTE_TO_NIB(n)  ((n) * 2)
 220
 221 #define BIT_TO_BYTE(n)  ((n) / 8)
 222 #define BIT_TO_NIB(n)   ((n) / 4)
 223
 224 #define NIB_TO_BYTE(n)  ((n) / 2)
 225 #define NIB_TO_BIT(n)   ((n) * 4)
 226
 227 #endif
 228