1 /* 2 * Copyright (c) 2011 Apple Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. The rights granted to you under the License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 13 * terms of an Apple operating system software license agreement. 14 * 15 * Please obtain a copy of the License at 16 * http://www.opensource.apple.com/apsl/ and read it before using this file. 17 * 18 * The Original Code and all software distributed under the License are 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28 29 #ifndef _NET_FLOWHASH_H_ 30 #define _NET_FLOWHASH_H_ 31 32 #include <sys/types.h> 33 34 #ifdef __cplusplus 35 extern "C" { 36 #endif 37 38 /* 39 * If 32-bit hash value is too large, use this macro to truncate 40 * it to n-bit; masking is a faster operation than modulus. 41 */ 42 #define HASHMASK(n) ((1UL << (n)) - 1) 43 44 /* 45 * Returns 32-bit hash value. Hashes which are capable of returning 46 * more bits currently have their results truncated to 32-bit. 47 */ 48 typedef u_int32_t net_flowhash_fn_t(const void *, u_int32_t, const u_int32_t); 49 50 extern net_flowhash_fn_t *net_flowhash; 51 extern net_flowhash_fn_t net_flowhash_mh3_x86_32; 52 extern net_flowhash_fn_t net_flowhash_mh3_x64_128; 53 extern net_flowhash_fn_t net_flowhash_jhash; 54 #ifdef __cplusplus 55 } 56 #endif 57 58 #endif /* _NET_FLOWHASH_H_ */ 59