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 * $FreeBSD$ 33 */ 34 35 #ifndef _MACHINE_IN_CKSUM_H_ 36 #define _MACHINE_IN_CKSUM_H_ 1 37 38 /* 39 * MP safe (alfred) 40 */ 41 42 #include <sys/cdefs.h> 43 44 #define in_cksum(m, len) in_cksum_skip(m, len, 0) 45 46 /* 47 * It it useful to have an Internet checksum routine which is inlineable 48 * and optimized specifically for the task of computing IP header checksums 49 * in the normal case (where there are no options and the header length is 50 * therefore always exactly five 32-bit words. 51 */ 52 #if defined(__GNUC__) && !defined(__INTEL_COMPILER) 53 static __inline u_int 54 in_cksum_hdr(const struct ip *ip) 55 { 56 register u_int sum = 0; 57 58 /* __volatile is necessary here because the condition codes are used. */ 59 #define ADD(n) __asm __volatile ("addl %1, %0" : "+r" (sum) : \ 60 "g" (((const u_int32_t *)ip)[n / 4])) 61 #define ADDC(n) __asm __volatile ("adcl %1, %0" : "+r" (sum) : \ 62 "g" (((const u_int32_t *)ip)[n / 4])) 63 #define MOP __asm __volatile ("adcl $0, %0" : "+r" (sum)) 64 65 ADD(0); 66 ADDC(4); 67 ADDC(8); 68 ADDC(12); 69 ADDC(16); 70 MOP; 71 #undef ADD 72 #undef ADDC 73 #undef MOP 74 sum = (sum & 0xffff) + (sum >> 16); 75 if (sum > 0xffff) 76 sum -= 0xffff; 77 78 return ~sum & 0xffff; 79 } 80 81 static __inline void 82 in_cksum_update(struct ip *ip) 83 { 84 int __tmpsum; 85 __tmpsum = (int)ntohs(ip->ip_sum) + 256; 86 ip->ip_sum = htons(__tmpsum + (__tmpsum >> 16)); 87 } 88 89 static __inline u_short 90 in_addword(u_short sum, u_short b) 91 { 92 /* __volatile is necessary because the condition codes are used. */ 93 __asm __volatile ("addw %1, %0" : "+r" (sum) : "r" (b)); 94 __asm __volatile ("adcw $0, %0" : "+r" (sum)); 95 96 return (sum); 97 } 98 99 static __inline u_short 100 in_pseudo(u_int sum, u_int b, u_int c) 101 { 102 /* __volatile is necessary because the condition codes are used. */ 103 __asm __volatile ("addl %1, %0" : "+r" (sum) : "g" (b)); 104 __asm __volatile ("adcl %1, %0" : "+r" (sum) : "g" (c)); 105 __asm __volatile ("adcl $0, %0" : "+r" (sum)); 106 107 sum = (sum & 0xffff) + (sum >> 16); 108 if (sum > 0xffff) 109 sum -= 0xffff; 110 return (sum); 111 } 112 113 #else 114 #define in_cksum_update(ip) \ 115 do { \ 116 int __tmpsum; \ 117 __tmpsum = (int)ntohs(ip->ip_sum) + 256; \ 118 ip->ip_sum = htons(__tmpsum + (__tmpsum >> 16)); \ 119 } while(0) 120 121 #endif 122 123 #ifdef _KERNEL 124 #if !defined(__GNUC__) || defined(__INTEL_COMPILER) 125 u_int in_cksum_hdr(const struct ip *ip); 126 u_short in_addword(u_short sum, u_short b); 127 u_short in_pseudo(u_int sum, u_int b, u_int c); 128 #endif 129 u_short in_cksum_skip(struct mbuf *m, int len, int skip); 130 #endif /* _KERNEL */ 131 132 #endif /* _MACHINE_IN_CKSUM_H_ */ 133