in_cksum.h revision 143063
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 143063 2005-03-02 21:33:29Z joerg $ 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 register u_int sum = 0; 61 62 __asm __volatile ( 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 ); 76 sum = (sum & 0xffff) + (sum >> 16); 77 if (sum > 0xffff) 78 sum -= 0xffff; 79 80 return ~sum & 0xffff; 81} 82 83static __inline void 84in_cksum_update(struct ip *ip) 85{ 86 int __tmpsum; 87 __tmpsum = (int)ntohs(ip->ip_sum) + 256; 88 ip->ip_sum = htons(__tmpsum + (__tmpsum >> 16)); 89} 90 91static __inline u_short 92in_addword(u_short sum, u_short b) 93{ 94 /* __volatile is necessary because the condition codes are used. */ 95 __asm __volatile ("addw %1, %0" : "+r" (sum) : "r" (b)); 96 __asm __volatile ("adcw $0, %0" : "+r" (sum)); 97 98 return (sum); 99} 100 101static __inline u_short 102in_pseudo(u_int sum, u_int b, u_int c) 103{ 104 /* __volatile is necessary because the condition codes are used. */ 105 __asm __volatile ("addl %1, %0" : "+r" (sum) : "g" (b)); 106 __asm __volatile ("adcl %1, %0" : "+r" (sum) : "g" (c)); 107 __asm __volatile ("adcl $0, %0" : "+r" (sum)); 108 109 sum = (sum & 0xffff) + (sum >> 16); 110 if (sum > 0xffff) 111 sum -= 0xffff; 112 return (sum); 113} 114 115#else 116#define in_cksum_update(ip) \ 117 do { \ 118 int __tmpsum; \ 119 __tmpsum = (int)ntohs(ip->ip_sum) + 256; \ 120 ip->ip_sum = htons(__tmpsum + (__tmpsum >> 16)); \ 121 } while(0) 122 123#endif 124 125#ifdef _KERNEL 126#if !defined(__GNUCLIKE_ASM) || defined(__INTEL_COMPILER) 127u_int in_cksum_hdr(const struct ip *ip); 128u_short in_addword(u_short sum, u_short b); 129u_short in_pseudo(u_int sum, u_int b, u_int c); 130#endif 131u_short in_cksum_skip(struct mbuf *m, int len, int skip); 132#endif /* _KERNEL */ 133 134#endif /* _MACHINE_IN_CKSUM_H_ */ 135