Changes in uspace/lib/net/generic/net_checksum.c [00d7e1b:ccca251] in mainline
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uspace/lib/net/generic/net_checksum.c
r00d7e1b rccca251 40 40 41 41 /** Big-endian encoding CRC divider. */ 42 #define CRC_DIVIDER_BE 42 #define CRC_DIVIDER_BE 0x04c11db7 43 43 44 44 /** 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 49 46 50 47 /** Compacts the computed checksum to the 16 bit number adding the carries. … … 206 203 } 207 204 208 /** Compute the IPheader checksum.205 /** Computes the ip header checksum. 209 206 * 210 207 * To compute the checksum of a new packet, the checksum header field must be … … 224 221 } 225 222 226 /** Compute the standard hash from MAC227 *228 * Hashing MAC into 64 possible values and using the value as index to229 * 64bit number.230 *231 * The code is copied from qemu-0.13's implementation of ne2000 and rt8139232 * drivers, but according to documentation there it originates in FreeBSD.233 *234 * @param[in] addr The 6-byte MAC address to be hashed235 *236 * @return 64-bit number with only single bit set to 1237 *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 }260 261 223 /** @} 262 224 */
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