1 /* 2 * util/rfc_1982.h - RFC 1982 Serial Number Arithmetic 3 * 4 * Copyright (c) 2023, NLnet Labs. All rights reserved. 5 * 6 * This software is open source. 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 notice, 13 * this list of conditions and the following disclaimer. 14 * 15 * Redistributions in binary form must reproduce the above copyright notice, 16 * this list of conditions and the following disclaimer in the documentation 17 * and/or other materials provided with the distribution. 18 * 19 * Neither the name of the NLNET LABS nor the names of its contributors may 20 * be used to endorse or promote products derived from this software without 21 * specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 27 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 29 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 30 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 31 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 32 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 33 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 /** 37 * \file 38 * 39 * This file contains functions for RFC 1982 serial number arithmetic. 40 */ 41 #ifndef RFC_1982_H 42 #define RFC_1982_H 43 44 /** 45 * RFC 1982 comparison, uses unsigned integers, and tries to avoid 46 * compiler optimization (eg. by avoiding a-b<0 comparisons). 47 * @param a: value to compare. 48 * @param b: value to compare. 49 * @return 0 if equal, 1 if a > b, else -1. 50 */ 51 int compare_1982(uint32_t a, uint32_t b); 52 53 /** 54 * RFC 1982 subtraction, uses unsigned integers, and tries to avoid 55 * compiler optimization (eg. by avoiding a-b<0 comparisons). 56 * @param a: value to subtract from. 57 * @param b: value to subtract. 58 * @return the difference between them if we know that b is larger than a, 59 * that is the distance between them in serial number arithmetic. 60 */ 61 uint32_t subtract_1982(uint32_t a, uint32_t b); 62 63 #endif /* RFC_1982_H */ 64