| /* SCTP kernel reference Implementation |
| * Copyright (c) 1999-2001 Motorola, Inc. |
| * Copyright (c) 2001-2003 International Business Machines, Corp. |
| * |
| * This file is part of the SCTP kernel reference Implementation |
| * |
| * SCTP Checksum functions |
| * |
| * The SCTP reference implementation is free software; |
| * you can redistribute it and/or modify it under the terms of |
| * the GNU General Public License as published by |
| * the Free Software Foundation; either version 2, or (at your option) |
| * any later version. |
| * |
| * The SCTP reference implementation is distributed in the hope that it |
| * will be useful, but WITHOUT ANY WARRANTY; without even the implied |
| * ************************ |
| * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. |
| * See the GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with GNU CC; see the file COPYING. If not, write to |
| * the Free Software Foundation, 59 Temple Place - Suite 330, |
| * Boston, MA 02111-1307, USA. |
| * |
| * Please send any bug reports or fixes you make to the |
| * email address(es): |
| * lksctp developers <lksctp-developers@lists.sourceforge.net> |
| * |
| * Or submit a bug report through the following website: |
| * http://www.sf.net/projects/lksctp |
| * |
| * Written or modified by: |
| * Dinakaran Joseph |
| * Jon Grimm <jgrimm@us.ibm.com> |
| * Sridhar Samudrala <sri@us.ibm.com> |
| * |
| * Any bugs reported given to us we will try to fix... any fixes shared will |
| * be incorporated into the next SCTP release. |
| */ |
| |
| /* The following code has been taken directly from |
| * draft-ietf-tsvwg-sctpcsum-03.txt |
| * |
| * The code has now been modified specifically for SCTP knowledge. |
| */ |
| |
| #include <linux/types.h> |
| #include <net/sctp/sctp.h> |
| |
| #define CRC32C_POLY 0x1EDC6F41 |
| #define CRC32C(c,d) (c=(c>>8)^crc_c[(c^(d))&0xFF]) |
| /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| /* Copyright 2001, D. Otis. Use this program, code or tables */ |
| /* extracted from it, as desired without restriction. */ |
| /* */ |
| /* 32 Bit Reflected CRC table generation for SCTP. */ |
| /* To accommodate serial byte data being shifted out least */ |
| /* significant bit first, the table's 32 bit words are reflected */ |
| /* which flips both byte and bit MS and LS positions. The CRC */ |
| /* is calculated MS bits first from the perspective of the serial*/ |
| /* stream. The x^32 term is implied and the x^0 term may also */ |
| /* be shown as +1. The polynomial code used is 0x1EDC6F41. */ |
| /* Castagnoli93 */ |
| /* x^32+x^28+x^27+x^26+x^25+x^23+x^22+x^20+x^19+x^18+x^14+x^13+ */ |
| /* x^11+x^10+x^9+x^8+x^6+x^0 */ |
| /* Guy Castagnoli Stefan Braeuer and Martin Herrman */ |
| /* "Optimization of Cyclic Redundancy-Check Codes */ |
| /* with 24 and 32 Parity Bits", */ |
| /* IEEE Transactions on Communications, Vol.41, No.6, June 1993 */ |
| /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ |
| static const __u32 crc_c[256] = { |
| 0x00000000, 0xF26B8303, 0xE13B70F7, 0x1350F3F4, |
| 0xC79A971F, 0x35F1141C, 0x26A1E7E8, 0xD4CA64EB, |
| 0x8AD958CF, 0x78B2DBCC, 0x6BE22838, 0x9989AB3B, |
| 0x4D43CFD0, 0xBF284CD3, 0xAC78BF27, 0x5E133C24, |
| 0x105EC76F, 0xE235446C, 0xF165B798, 0x030E349B, |
| 0xD7C45070, 0x25AFD373, 0x36FF2087, 0xC494A384, |
| 0x9A879FA0, 0x68EC1CA3, 0x7BBCEF57, 0x89D76C54, |
| 0x5D1D08BF, 0xAF768BBC, 0xBC267848, 0x4E4DFB4B, |
| 0x20BD8EDE, 0xD2D60DDD, 0xC186FE29, 0x33ED7D2A, |
| 0xE72719C1, 0x154C9AC2, 0x061C6936, 0xF477EA35, |
| 0xAA64D611, 0x580F5512, 0x4B5FA6E6, 0xB93425E5, |
| 0x6DFE410E, 0x9F95C20D, 0x8CC531F9, 0x7EAEB2FA, |
| 0x30E349B1, 0xC288CAB2, 0xD1D83946, 0x23B3BA45, |
| 0xF779DEAE, 0x05125DAD, 0x1642AE59, 0xE4292D5A, |
| 0xBA3A117E, 0x4851927D, 0x5B016189, 0xA96AE28A, |
| 0x7DA08661, 0x8FCB0562, 0x9C9BF696, 0x6EF07595, |
| 0x417B1DBC, 0xB3109EBF, 0xA0406D4B, 0x522BEE48, |
| 0x86E18AA3, 0x748A09A0, 0x67DAFA54, 0x95B17957, |
| 0xCBA24573, 0x39C9C670, 0x2A993584, 0xD8F2B687, |
| 0x0C38D26C, 0xFE53516F, 0xED03A29B, 0x1F682198, |
| 0x5125DAD3, 0xA34E59D0, 0xB01EAA24, 0x42752927, |
| 0x96BF4DCC, 0x64D4CECF, 0x77843D3B, 0x85EFBE38, |
| 0xDBFC821C, 0x2997011F, 0x3AC7F2EB, 0xC8AC71E8, |
| 0x1C661503, 0xEE0D9600, 0xFD5D65F4, 0x0F36E6F7, |
| 0x61C69362, 0x93AD1061, 0x80FDE395, 0x72966096, |
| 0xA65C047D, 0x5437877E, 0x4767748A, 0xB50CF789, |
| 0xEB1FCBAD, 0x197448AE, 0x0A24BB5A, 0xF84F3859, |
| 0x2C855CB2, 0xDEEEDFB1, 0xCDBE2C45, 0x3FD5AF46, |
| 0x7198540D, 0x83F3D70E, 0x90A324FA, 0x62C8A7F9, |
| 0xB602C312, 0x44694011, 0x5739B3E5, 0xA55230E6, |
| 0xFB410CC2, 0x092A8FC1, 0x1A7A7C35, 0xE811FF36, |
| 0x3CDB9BDD, 0xCEB018DE, 0xDDE0EB2A, 0x2F8B6829, |
| 0x82F63B78, 0x709DB87B, 0x63CD4B8F, 0x91A6C88C, |
| 0x456CAC67, 0xB7072F64, 0xA457DC90, 0x563C5F93, |
| 0x082F63B7, 0xFA44E0B4, 0xE9141340, 0x1B7F9043, |
| 0xCFB5F4A8, 0x3DDE77AB, 0x2E8E845F, 0xDCE5075C, |
| 0x92A8FC17, 0x60C37F14, 0x73938CE0, 0x81F80FE3, |
| 0x55326B08, 0xA759E80B, 0xB4091BFF, 0x466298FC, |
| 0x1871A4D8, 0xEA1A27DB, 0xF94AD42F, 0x0B21572C, |
| 0xDFEB33C7, 0x2D80B0C4, 0x3ED04330, 0xCCBBC033, |
| 0xA24BB5A6, 0x502036A5, 0x4370C551, 0xB11B4652, |
| 0x65D122B9, 0x97BAA1BA, 0x84EA524E, 0x7681D14D, |
| 0x2892ED69, 0xDAF96E6A, 0xC9A99D9E, 0x3BC21E9D, |
| 0xEF087A76, 0x1D63F975, 0x0E330A81, 0xFC588982, |
| 0xB21572C9, 0x407EF1CA, 0x532E023E, 0xA145813D, |
| 0x758FE5D6, 0x87E466D5, 0x94B49521, 0x66DF1622, |
| 0x38CC2A06, 0xCAA7A905, 0xD9F75AF1, 0x2B9CD9F2, |
| 0xFF56BD19, 0x0D3D3E1A, 0x1E6DCDEE, 0xEC064EED, |
| 0xC38D26C4, 0x31E6A5C7, 0x22B65633, 0xD0DDD530, |
| 0x0417B1DB, 0xF67C32D8, 0xE52CC12C, 0x1747422F, |
| 0x49547E0B, 0xBB3FFD08, 0xA86F0EFC, 0x5A048DFF, |
| 0x8ECEE914, 0x7CA56A17, 0x6FF599E3, 0x9D9E1AE0, |
| 0xD3D3E1AB, 0x21B862A8, 0x32E8915C, 0xC083125F, |
| 0x144976B4, 0xE622F5B7, 0xF5720643, 0x07198540, |
| 0x590AB964, 0xAB613A67, 0xB831C993, 0x4A5A4A90, |
| 0x9E902E7B, 0x6CFBAD78, 0x7FAB5E8C, 0x8DC0DD8F, |
| 0xE330A81A, 0x115B2B19, 0x020BD8ED, 0xF0605BEE, |
| 0x24AA3F05, 0xD6C1BC06, 0xC5914FF2, 0x37FACCF1, |
| 0x69E9F0D5, 0x9B8273D6, 0x88D28022, 0x7AB90321, |
| 0xAE7367CA, 0x5C18E4C9, 0x4F48173D, 0xBD23943E, |
| 0xF36E6F75, 0x0105EC76, 0x12551F82, 0xE03E9C81, |
| 0x34F4F86A, 0xC69F7B69, 0xD5CF889D, 0x27A40B9E, |
| 0x79B737BA, 0x8BDCB4B9, 0x988C474D, 0x6AE7C44E, |
| 0xBE2DA0A5, 0x4C4623A6, 0x5F16D052, 0xAD7D5351, |
| }; |
| |
| __u32 sctp_start_cksum(__u8 *buffer, __u16 length) |
| { |
| __u32 crc32 = ~(__u32) 0; |
| __u32 i; |
| |
| /* Optimize this routine to be SCTP specific, knowing how |
| * to skip the checksum field of the SCTP header. |
| */ |
| |
| /* Calculate CRC up to the checksum. */ |
| for (i = 0; i < (sizeof(struct sctphdr) - sizeof(__u32)); i++) |
| CRC32C(crc32, buffer[i]); |
| |
| /* Skip checksum field of the header. */ |
| for (i = 0; i < sizeof(__u32); i++) |
| CRC32C(crc32, 0); |
| |
| /* Calculate the rest of the CRC. */ |
| for (i = sizeof(struct sctphdr); i < length ; i++) |
| CRC32C(crc32, buffer[i]); |
| |
| return crc32; |
| } |
| |
| __u32 sctp_update_cksum(__u8 *buffer, __u16 length, __u32 crc32) |
| { |
| __u32 i; |
| |
| for (i = 0; i < length ; i++) |
| CRC32C(crc32, buffer[i]); |
| |
| return crc32; |
| } |
| |
| __u32 sctp_update_copy_cksum(__u8 *to, __u8 *from, __u16 length, __u32 crc32) |
| { |
| __u32 i; |
| __u32 *_to = (__u32 *)to; |
| __u32 *_from = (__u32 *)from; |
| |
| for (i = 0; i < (length/4); i++) { |
| _to[i] = _from[i]; |
| CRC32C(crc32, from[i*4]); |
| CRC32C(crc32, from[i*4+1]); |
| CRC32C(crc32, from[i*4+2]); |
| CRC32C(crc32, from[i*4+3]); |
| } |
| |
| return crc32; |
| } |
| |
| __u32 sctp_end_cksum(__u32 crc32) |
| { |
| __u32 result; |
| __u8 byte0, byte1, byte2, byte3; |
| |
| result = ~crc32; |
| |
| /* result now holds the negated polynomial remainder; |
| * since the table and algorithm is "reflected" [williams95]. |
| * That is, result has the same value as if we mapped the message |
| * to a polyomial, computed the host-bit-order polynomial |
| * remainder, performed final negation, then did an end-for-end |
| * bit-reversal. |
| * Note that a 32-bit bit-reversal is identical to four inplace |
| * 8-bit reversals followed by an end-for-end byteswap. |
| * In other words, the bytes of each bit are in the right order, |
| * but the bytes have been byteswapped. So we now do an explicit |
| * byteswap. On a little-endian machine, this byteswap and |
| * the final ntohl cancel out and could be elided. |
| */ |
| byte0 = result & 0xff; |
| byte1 = (result>>8) & 0xff; |
| byte2 = (result>>16) & 0xff; |
| byte3 = (result>>24) & 0xff; |
| |
| crc32 = ((byte0 << 24) | |
| (byte1 << 16) | |
| (byte2 << 8) | |
| byte3); |
| return crc32; |
| } |
