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Diffstat (limited to 'net/sctp/crc32c.c')
| -rw-r--r-- | net/sctp/crc32c.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/net/sctp/crc32c.c b/net/sctp/crc32c.c new file mode 100644 index 000000000000..31f05ec8e1d3 --- /dev/null +++ b/net/sctp/crc32c.c @@ -0,0 +1,220 @@ +/* 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; +} |