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: releng/8.0/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)
57 static __inline u_int
58 in_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
84 static __inline void
85 in_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
92 static __inline u_short
93 in_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
105 static __inline u_short
106 in_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)
135 u_int in_cksum_hdr(const struct ip *ip);
136 u_short in_addword(u_short sum, u_short b);
137 u_short in_pseudo(u_int sum, u_int b, u_int c);
138 #endif
139 u_short in_cksum_skip(struct mbuf *m, int len, int skip);
140 #endif /* _KERNEL */
141
142 #endif /* _MACHINE_IN_CKSUM_H_ */
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