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 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * from tahoe: in_cksum.c 1.2 86/01/05 34 * from: @(#)in_cksum.c 1.3 (Berkeley) 1/19/91 35 * from: Id: in_cksum.c,v 1.8 1995/12/03 18:35:19 bde Exp 36 * $Id: in_cksum.h,v 1.4 1997/02/22 09:34:42 peter Exp $ 37 */ 38 39 #ifndef _MACHINE_IN_CKSUM_H_ 40 #define _MACHINE_IN_CKSUM_H_ 1 41 42 #include <sys/cdefs.h> 43 44 /* 45 * It it useful to have an Internet checksum routine which is inlineable 46 * and optimized specifically for the task of computing IP header checksums 47 * in the normal case (where there are no options and the header length is 48 * therefore always exactly five 32-bit words. 49 */ 50 #ifdef __GNUC__ 51 static __inline u_int 52 in_cksum_hdr(const struct ip *ip) 53 { 54 register u_int sum = 0; 55 56 #define ADD(n) __asm("addl " #n "(%2), %0" : "=r" (sum) : "0" (sum), "r" (ip)) 57 #define ADDC(n) __asm("adcl " #n "(%2), %0" : "=r" (sum) : "0" (sum), "r" (ip)) 58 #define MOP __asm("adcl $0, %0" : "=r" (sum) : "0" (sum)) 59 60 ADD(0); 61 ADDC(4); 62 ADDC(8); 63 ADDC(12); 64 ADDC(16); 65 MOP; 66 #undef ADD 67 #undef ADDC 68 #undef MOP 69 sum = (sum & 0xffff) + (sum >> 16); 70 if (sum > 0xffff) 71 sum -= 0xffff; 72 73 return ~sum & 0xffff; 74 } 75 76 static __inline void 77 in_cksum_update(struct ip *ip) 78 { 79 int __tmpsum; 80 __tmpsum = (int)ntohs(ip->ip_sum) + 256; 81 ip->ip_sum = htons(__tmpsum + (__tmpsum >> 16)); 82 } 83 84 #else 85 u_int in_cksum_hdr __P((const struct ip *)); 86 #define in_cksum_update(ip) \ 87 do { \ 88 int __tmpsum; \ 89 __tmpsum = (int)ntohs(ip->ip_sum) + 256; \ 90 ip->ip_sum = htons(__tmpsum + (__tmpsum >> 16)); \ 91 } while(0) 92 93 #endif 94 95 typedef unsigned in_psum_t; 96 #ifdef KERNEL 97 in_psum_t in_cksum_partial(in_psum_t psum, const u_short *w, int len); 98 int in_cksum_finalize(in_psum_t psum); 99 #endif /* KERNEL */ 100 101 #endif /* _MACHINE_IN_CKSUM_H_ */ 102