in_cksum.h revision 194111
1/*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * from tahoe: in_cksum.c 1.2 86/01/05 30 * from: @(#)in_cksum.c 1.3 (Berkeley) 1/19/91 31 * from: Id: in_cksum.c,v 1.8 1995/12/03 18:35:19 bde Exp 32 * $FreeBSD: head/sys/i386/include/in_cksum.h 194111 2009-06-13 14:00:10Z ed $ 33 */ 34 35#ifndef _MACHINE_IN_CKSUM_H_ 36#define _MACHINE_IN_CKSUM_H_ 1 37 38#ifndef _SYS_CDEFS_H_ 39#error this file needs sys/cdefs.h as a prerequisite 40#endif 41 42/* 43 * MP safe (alfred) 44 */ 45 46#include <sys/cdefs.h> 47 48#define in_cksum(m, len) in_cksum_skip(m, len, 0) 49 50/* 51 * It it useful to have an Internet checksum routine which is inlineable 52 * and optimized specifically for the task of computing IP header checksums 53 * in the normal case (where there are no options and the header length is 54 * therefore always exactly five 32-bit words. 55 */ 56#if defined(__GNUCLIKE_ASM) && !defined(__INTEL_COMPILER) 57static __inline u_int 58in_cksum_hdr(const struct ip *ip) 59{ 60 u_int sum = 0; 61 62 __asm( 63 "addl %1, %0\n" 64 "adcl %2, %0\n" 65 "adcl %3, %0\n" 66 "adcl %4, %0\n" 67 "adcl %5, %0\n" 68 "adcl $0, %0" 69 : "+r" (sum) 70 : "g" (((const u_int32_t *)ip)[0]), 71 "g" (((const u_int32_t *)ip)[1]), 72 "g" (((const u_int32_t *)ip)[2]), 73 "g" (((const u_int32_t *)ip)[3]), 74 "g" (((const u_int32_t *)ip)[4]) 75 : "cc" 76 ); 77 sum = (sum & 0xffff) + (sum >> 16); 78 if (sum > 0xffff) 79 sum -= 0xffff; 80 81 return ~sum & 0xffff; 82} 83 84static __inline void 85in_cksum_update(struct ip *ip) 86{ 87 int __tmpsum; 88 __tmpsum = (int)ntohs(ip->ip_sum) + 256; 89 ip->ip_sum = htons(__tmpsum + (__tmpsum >> 16)); 90} 91 92static __inline u_short 93in_addword(u_short sum, u_short b) 94{ 95 __asm( 96 "addw %1, %0\n" 97 "adcw $0, %0" 98 : "+r" (sum) 99 : "g" (b) 100 : "cc" 101 ); 102 return (sum); 103} 104 105static __inline u_short 106in_pseudo(u_int sum, u_int b, u_int c) 107{ 108 __asm( 109 "addl %1, %0\n" 110 "adcl %2, %0\n" 111 "adcl $0, %0" 112 : "+r" (sum) 113 : "g" (b), 114 "g" (c) 115 : "cc" 116 ); 117 sum = (sum & 0xffff) + (sum >> 16); 118 if (sum > 0xffff) 119 sum -= 0xffff; 120 return (sum); 121} 122 123#else 124#define in_cksum_update(ip) \ 125 do { \ 126 int __tmpsum; \ 127 __tmpsum = (int)ntohs(ip->ip_sum) + 256; \ 128 ip->ip_sum = htons(__tmpsum + (__tmpsum >> 16)); \ 129 } while(0) 130 131#endif 132 133#ifdef _KERNEL 134#if !defined(__GNUCLIKE_ASM) || defined(__INTEL_COMPILER) 135u_int in_cksum_hdr(const struct ip *ip); 136u_short in_addword(u_short sum, u_short b); 137u_short in_pseudo(u_int sum, u_int b, u_int c); 138#endif 139u_short in_cksum_skip(struct mbuf *m, int len, int skip); 140#endif /* _KERNEL */ 141 142#endif /* _MACHINE_IN_CKSUM_H_ */ 143