Go to the source code of this file.
Functions | |
| bool | zrtpCheckCksum (uint8_t *buffer, uint16_t length, uint32_t crc32) |
| uint32_t | zrtpGenerateCksum (uint8_t *buffer, uint16_t length) |
| uint32_t | zrtpEndCksum (uint32_t crc32) |
|
||||||||||||||||
|
Definition at line 140 of file ZrtpCrc32.cxx. References zrtpEndCksum(), and zrtpGenerateCksum(). Referenced by ZrtpQueue::takeInDataPacket(). 00141 { 00142 uint32_t chksum = zrtpGenerateCksum(buffer, length); 00143 chksum = zrtpEndCksum(chksum); 00144 // fprintf(stderr, "Received crc %x, computed crc: %x\n", crc32, chksum); 00145 return (crc32 == chksum); 00146 }
|
|
|
Definition at line 161 of file ZrtpCrc32.cxx. Referenced by ZrtpQueue::sendDataZRTP(), and zrtpCheckCksum(). 00162 { 00163 uint32_t result; 00164 uint8_t byte0, byte1, byte2, byte3; 00165 00166 result = ~crc32; 00167 00168 /* result now holds the negated polynomial remainder; 00169 * since the table and algorithm is "reflected" [williams95]. 00170 * That is, result has the same value as if we mapped the message 00171 * to a polyomial, computed the host-bit-order polynomial 00172 * remainder, performed final negation, then did an end-for-end 00173 * bit-reversal. 00174 * Note that a 32-bit bit-reversal is identical to four inplace 00175 * 8-bit reversals followed by an end-for-end byteswap. 00176 * In other words, the bytes of each bit are in the right order, 00177 * but the bytes have been byteswapped. So we now do an explicit 00178 * byteswap. On a little-endian machine, this byteswap and 00179 * the final ntohl cancel out and could be elided. 00180 */ 00181 byte0 = result & 0xff; 00182 byte1 = (result>>8) & 0xff; 00183 byte2 = (result>>16) & 0xff; 00184 byte3 = (result>>24) & 0xff; 00185 00186 crc32 = ((byte0 << 24) | 00187 (byte1 << 16) | 00188 (byte2 << 8) | 00189 byte3); 00190 // fprintf(stderr, "Computed crc32: %x\n", crc32); 00191 return crc32; 00192 }
|
|
||||||||||||
|
Definition at line 148 of file ZrtpCrc32.cxx. References CRC32C. Referenced by ZrtpQueue::sendDataZRTP(), and zrtpCheckCksum(). 00149 { 00150 uint32_t crc32 = ~(uint32_t) 0; 00151 uint32_t i; 00152 00153 // fprintf(stderr, "Buffer %xl, length: %d\n", buffer, length); 00154 /* Calculate the CRC. */ 00155 for (i = 0; i < length ; i++) 00156 CRC32C(crc32, buffer[i]); 00157 00158 return crc32; 00159 }
|