xref: /freebsd/sys/amd64/include/in_cksum.h (revision cc16dea626cf2fc80cde667ac4798065108e596c)
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 #ifndef _SYS_CDEFS_H_
39 #error this file needs sys/cdefs.h as a prerequisite
40 #endif
41 
42 #include <sys/cdefs.h>
43 
44 #define in_cksum(m, len)	in_cksum_skip(m, len, 0)
45 
46 #if defined(IPVERSION) && (IPVERSION == 4)
47 /*
48  * It it useful to have an Internet checksum routine which is inlineable
49  * and optimized specifically for the task of computing IP header checksums
50  * in the normal case (where there are no options and the header length is
51  * therefore always exactly five 32-bit words.
52  */
53 #ifdef __CC_SUPPORTS___INLINE
54 
55 static __inline void
56 in_cksum_update(struct ip *ip)
57 {
58 	int __tmpsum;
59 	__tmpsum = (int)ntohs(ip->ip_sum) + 256;
60 	ip->ip_sum = htons(__tmpsum + (__tmpsum >> 16));
61 }
62 
63 #else
64 
65 #define	in_cksum_update(ip) \
66 	do { \
67 		int __tmpsum; \
68 		__tmpsum = (int)ntohs(ip->ip_sum) + 256; \
69 		ip->ip_sum = htons(__tmpsum + (__tmpsum >> 16)); \
70 	} while(0)
71 
72 #endif
73 #endif
74 
75 #ifdef _KERNEL
76 #if defined(IPVERSION) && (IPVERSION == 4)
77 u_int in_cksum_hdr(const struct ip *ip);
78 #endif
79 u_short	in_addword(u_short sum, u_short b);
80 u_short	in_pseudo(u_int sum, u_int b, u_int c);
81 u_short	in_cksum_skip(struct mbuf *m, int len, int skip);
82 #endif
83 
84 #endif /* _MACHINE_IN_CKSUM_H_ */
85