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  • uspace/lib/net/generic/net_checksum.c

    r00d7e1b rccca251  
    4040
    4141/** Big-endian encoding CRC divider. */
    42 #define CRC_DIVIDER_BE  0x04c11db7
     42#define CRC_DIVIDER_BE  0x04c11db7
    4343
    4444/** Little-endian encoding CRC divider. */
    45 #define CRC_DIVIDER_LE  0xedb88320
    46 
    47 /** Polynomial used in multicast address hashing */
    48 #define CRC_MCAST_POLYNOMIAL  0x04c11db6
     45#define CRC_DIVIDER_LE  0xedb88320
    4946
    5047/** Compacts the computed checksum to the 16 bit number adding the carries.
     
    206203}
    207204
    208 /** Compute the IP header checksum.
     205/** Computes the ip header checksum.
    209206 *
    210207 * To compute the checksum of a new packet, the checksum header field must be
     
    224221}
    225222
    226 /** Compute the standard hash from MAC
    227  *
    228  * Hashing MAC into 64 possible values and using the value as index to
    229  * 64bit number.
    230  *
    231  * The code is copied from qemu-0.13's implementation of ne2000 and rt8139
    232  * drivers, but according to documentation there it originates in FreeBSD.
    233  *
    234  * @param[in] addr The 6-byte MAC address to be hashed
    235  *
    236  * @return 64-bit number with only single bit set to 1
    237  *
    238  */
    239 uint64_t multicast_hash(const uint8_t addr[6])
    240 {
    241         uint32_t crc;
    242     int carry, i, j;
    243     uint8_t b;
    244 
    245     crc = 0xffffffff;
    246     for (i = 0; i < 6; i++) {
    247         b = addr[i];
    248         for (j = 0; j < 8; j++) {
    249             carry = ((crc & 0x80000000L) ? 1 : 0) ^ (b & 0x01);
    250             crc <<= 1;
    251             b >>= 1;
    252             if (carry)
    253                 crc = ((crc ^ CRC_MCAST_POLYNOMIAL) | carry);
    254         }
    255     }
    256        
    257     uint64_t one64 = 1;
    258     return one64 << (crc >> 26);
    259 }
    260 
    261223/** @}
    262224 */
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