/*
* Copyright (c) 2001, 2002, 2003, 2004 Cisco Systems, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Cisco Systems, Inc.
* 4. Neither the name of the project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY CISCO SYSTEMS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL CISCO SYSTEMS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
/* 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 */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
u_int32_t
update_crc32(u_int32_t crc32c,
unsigned char *buffer,
unsigned int length)
{
unsigned int i;
for (i = 0; i < length; i++) {
SCTP_CRC32C(crc32c, buffer[i]);
}
return (crc32c);
}
u_int32_t
sctp_csum_finalize(u_int32_t crc32c)
{
u_int32_t result;
#if BYTE_ORDER == BIG_ENDIAN
u_int8_t byte0, byte1, byte2, byte3;
#endif
/* Complement the result */
result = ~crc32c;
#if BYTE_ORDER == BIG_ENDIAN
/*
* For BIG-ENDIAN.. aka Motorola byte order the result is in
* little-endian form. So we must manually swap the bytes. Then
* we can call htonl() which does nothing...
*/
byte0 = result & 0x000000ff;
byte1 = (result >> 8) & 0x000000ff;
byte2 = (result >> 16) & 0x000000ff;
byte3 = (result >> 24) & 0x000000ff;
result = ((byte0 << 24) | (byte1 << 16) | (byte2 << 8) | byte3);
crc32c = htonl(result);
#else
/*
* For INTEL platforms the result comes out in network order.
* No htonl is required or the swap above. So we optimize out
* both the htonl and the manual swap above.
*/
crc32c = result;
#endif
return (crc32c);
}
