123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118 |
- /* $Id$ */
- /*
- * Copyright (c) 2001-2010 Aaron Turner <aturner at synfin dot net>
- * Copyright (c) 2013-2015 Fred Klassen <tcpreplay at appneta dot com> - AppNeta
- *
- * The Tcpreplay Suite of tools 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 3 of the
- * License, or with the authors permission any later version.
- *
- * The Tcpreplay Suite 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 the Tcpreplay Suite. If not, see <http://www.gnu.org/licenses/>.
- */
- #pragma once
- #include "defines.h"
- #include "config.h"
- /*
- * shamelessly stolen from Linux kernel
- *
- * Implements RFC 1624 (Incremental Internet Checksum)
- * 3. Discussion states :
- * HC' = ~(~HC + ~m + m')
- * m : old value of a 16bit field
- * m' : new value of a 16bit field
- */
- typedef uint16_t __le16;
- typedef uint16_t __be16;
- typedef uint32_t __le32;
- typedef uint32_t __be32;
- typedef uint16_t __sum16;
- typedef uint32_t __wsum;
- /*
- * Fold a partial checksum
- */
- static inline __sum16
- csum_fold(__wsum csum)
- {
- uint32_t sum = (uint32_t)csum;
- sum = (sum & 0xffff) + (sum >> 16);
- sum = (sum & 0xffff) + (sum >> 16);
- return (__sum16)~sum;
- }
- static inline __wsum
- csum_add(__wsum csum, __wsum addend)
- {
- uint32_t res = (uint32_t)csum;
- res += (uint32_t)addend;
- return (__wsum)(res + (res < (uint32_t)addend));
- }
- static inline __wsum
- csum_sub(__wsum csum, __wsum addend)
- {
- return csum_add(csum, ~addend);
- }
- static inline __sum16
- csum16_add(__sum16 csum, __be16 addend)
- {
- uint16_t res = (uint16_t)csum;
- res += (uint16_t)addend;
- return (__sum16)(res + (res < (uint16_t)addend));
- }
- static inline __sum16
- csum16_sub(__sum16 csum, __be16 addend)
- {
- return csum16_add(csum, ~addend);
- }
- static inline __wsum
- csum_unfold(__sum16 n)
- {
- return (__wsum)n;
- }
- __wsum csum_partial(const void *buff, int len, __wsum wsum);
- static inline void
- csum_replace16(__sum16 *sum, const __be32 *from, const __be32 *to)
- {
- __be32 diff[] = {
- ~from[0],
- ~from[1],
- ~from[2],
- ~from[3],
- to[0],
- to[1],
- to[2],
- to[3],
- };
- *sum = csum_fold(csum_partial(diff, sizeof(diff), ~csum_unfold(*sum)));
- }
- static inline void
- csum_replace4(__sum16 *sum, __be32 from, __be32 to)
- {
- *sum = csum_fold(csum_add(csum_sub(~csum_unfold(*sum), from), to));
- }
- static inline void
- csum_replace2(__sum16 *sum, __be16 from, __be16 to)
- {
- *sum = ~csum16_add(csum16_sub(~(*sum), from), to);
- }
|