1 /* SCTP kernel reference Implementation 2 * Copyright (c) 1999-2001 Motorola, Inc. 3 * Copyright (c) 2001-2003 International Business Machines, Corp. 4 * 5 * This file is part of the SCTP kernel reference Implementation 6 * 7 * SCTP Checksum functions 8 * 9 * The SCTP reference implementation is free software; 10 * you can redistribute it and/or modify it under the terms of 11 * the GNU General Public License as published by 12 * the Free Software Foundation; either version 2, or (at your option) 13 * any later version. 14 * 15 * The SCTP reference implementation is distributed in the hope that it 16 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 17 * ************************ 18 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 19 * See the GNU General Public License for more details. 20 * 21 * You should have received a copy of the GNU General Public License 22 * along with GNU CC; see the file COPYING. If not, write to 23 * the Free Software Foundation, 59 Temple Place - Suite 330, 24 * Boston, MA 02111-1307, USA. 25 * 26 * Please send any bug reports or fixes you make to the 27 * email address(es): 28 * lksctp developers <lksctp-developers@lists.sourceforge.net> 29 * 30 * Or submit a bug report through the following website: 31 * http://www.sf.net/projects/lksctp 32 * 33 * Written or modified by: 34 * Dinakaran Joseph 35 * Jon Grimm <jgrimm@us.ibm.com> 36 * Sridhar Samudrala <sri@us.ibm.com> 37 * 38 * Rewritten to use libcrc32c by: 39 * Vlad Yasevich <vladislav.yasevich@hp.com> 40 * 41 * Any bugs reported given to us we will try to fix... any fixes shared will 42 * be incorporated into the next SCTP release. 43 */ 44 45 #include <linux/types.h> 46 #include <net/sctp/sctp.h> 47 #include <linux/crc32c.h> 48 49 static inline __be32 sctp_crc32c(__be32 crc, u8 *buffer, u16 length) 50 { 51 return (__force __be32)crc32c((__force u32)crc, buffer, length); 52 } 53 54 static inline __be32 sctp_start_cksum(__u8 *buffer, __u16 length) 55 { 56 __be32 crc = ~cpu_to_be32(0); 57 __u8 zero[sizeof(__u32)] = {0}; 58 59 /* Optimize this routine to be SCTP specific, knowing how 60 * to skip the checksum field of the SCTP header. 61 */ 62 63 /* Calculate CRC up to the checksum. */ 64 crc = sctp_crc32c(crc, buffer, sizeof(struct sctphdr) - sizeof(__u32)); 65 66 /* Skip checksum field of the header. */ 67 crc = sctp_crc32c(crc, zero, sizeof(__u32)); 68 69 /* Calculate the rest of the CRC. */ 70 crc = sctp_crc32c(crc, &buffer[sizeof(struct sctphdr)], 71 length - sizeof(struct sctphdr)); 72 return crc; 73 } 74 75 static inline __be32 sctp_update_cksum(__u8 *buffer, __u16 length, __be32 crc32) 76 { 77 return sctp_crc32c(crc32, buffer, length); 78 } 79 80 static inline __be32 sctp_end_cksum(__be32 crc32) 81 { 82 return (__force __be32)~cpu_to_le32((__force u32)crc32); 83 } 84