1 /* 2 * This code implements the AUTODIN II polynomial used by Ethernet, 3 * and can be used to calculate multicast address hash indices. 4 * It assumes that the low order bits will be transmitted first, 5 * and consequently the low byte should be sent first when 6 * the crc computation is finished. The crc should be complemented 7 * before transmission. 8 * The variable corresponding to the macro argument "crc" should 9 * be an unsigned long and should be preset to all ones for Ethernet 10 * use. An error-free packet will leave 0xDEBB20E3 in the crc. 11 * Spencer Garrett <srg@quick.com> 12 */ 13 14 #include <sys/types.h> 15 16 #include <stdio.h> 17 #include <stdint.h> 18 #include <unistd.h> 19 20 #include "extern.h" 21 22 #define CRC(crc, ch) (crc = (crc >> 8) ^ crctab[(crc ^ (ch)) & 0xff]) 23 24 /* generated using the AUTODIN II polynomial 25 * x^32 + x^26 + x^23 + x^22 + x^16 + 26 * x^12 + x^11 + x^10 + x^8 + x^7 + x^5 + x^4 + x^2 + x^1 + 1 27 */ 28 static const uint32_t crctab[256] = { 29 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 30 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3, 31 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 32 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 33 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 34 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 35 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 36 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5, 37 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, 38 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 39 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 40 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59, 41 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 42 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f, 43 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 44 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 45 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 46 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433, 47 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 48 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, 49 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 50 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 51 0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 52 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65, 53 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 54 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 55 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, 56 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 57 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 58 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f, 59 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 60 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 61 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 62 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 63 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 64 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 65 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 66 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7, 67 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, 68 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 69 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 70 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b, 71 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 72 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79, 73 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 74 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 75 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 76 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d, 77 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 78 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, 79 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 80 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 81 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 82 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777, 83 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 84 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 85 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 86 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 87 0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 88 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, 89 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 90 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf, 91 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, 92 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d, 93 }; 94 95 static uint32_t crc32_total = 0; 96 97 int 98 crc32(int fd, uint32_t *cval, off_t *clen) 99 { 100 uint32_t lcrc = ~0; 101 int nr ; 102 off_t len ; 103 char buf[BUFSIZ], *p ; 104 105 len = 0 ; 106 crc32_total = ~crc32_total ; 107 while ((nr = read(fd, buf, sizeof(buf))) > 0) 108 for (len += nr, p = buf; nr--; ++p) { 109 CRC(lcrc, *p) ; 110 CRC(crc32_total, *p) ; 111 } 112 if (nr < 0) 113 return 1 ; 114 115 *clen = len ; 116 *cval = ~lcrc ; 117 crc32_total = ~crc32_total ; 118 return 0 ; 119 } 120