projects / people / ms / suricata.git / blame
| Commit | Line | Data |
|---|---|---|
| e0b9e852 JI |
1 | /* |
| 2 | * Reference: OpenBSD's pf.c. | |
| 3 | * | |
| 4 | * Copyright (c) 2001 Daniel Hartmeier | |
| 5 | * Copyright (c) 2002 - 2008 Henning Brauer | |
| 6 | * All rights reserved. | |
| 7 | * | |
| 8 | * Redistribution and use in source and binary forms, with or without | |
| 9 | * modification, are permitted provided that the following conditions | |
| 10 | * are met: | |
| 11 | * | |
| 12 | * - Redistributions of source code must retain the above copyright | |
| 13 | * notice, this list of conditions and the following disclaimer. | |
| 14 | * - Redistributions in binary form must reproduce the above | |
| 15 | * copyright notice, this list of conditions and the following | |
| 16 | * disclaimer in the documentation and/or other materials provided | |
| 17 | * with the distribution. | |
| 18 | * | |
| 19 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 20 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 21 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS | |
| 22 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE | |
| 23 | * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, | |
| 24 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, | |
| 25 | * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
| 26 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER | |
| 27 | * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
| 28 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN | |
| 29 | * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
| 30 | * POSSIBILITY OF SUCH DAMAGE. | |
| 31 | * | |
| 32 | * Effort sponsored in part by the Defense Advanced Research Projects | |
| 33 | * Agency (DARPA) and Air Force Research Laboratory, Air Force | |
| 34 | * Materiel Command, USAF, under agreement number F30602-01-2-0537. | |
| 35 | */ | |
| 36 | ||
| 37 | #include <stdint.h> | |
| 38 | ||
| ab1200fb VJ |
39 | #include "util-fix_checksum.h" |
| 40 | ||
| e0b9e852 JI |
41 | /** |
| 42 | * \brief Fix-up an IP checksum. | |
| 43 | * | |
| 44 | * \param sum The current checksum. | |
| 45 | * \param old Value of old header parameter. | |
| 46 | * \param new Value of new header parameter. | |
| 47 | * | |
| 48 | * \retval New checksum. | |
| 49 | */ | |
| 50 | uint16_t | |
| 51 | FixChecksum(uint16_t sum, uint16_t old, uint16_t new) | |
| 52 | { | |
| 53 | uint32_t l; | |
| 54 | ||
| 55 | l = sum + old - new; | |
| 56 | l = (l >> 16) + (l & 65535); | |
| 57 | l = l & 65535; | |
| 58 | ||
| 59 | return l; | |
| 60 | } |