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/9.2/sys/i386/include/in_cksum.h 238228 2012-07-08 10:46:55Z bz $
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 #if defined(IPVERSION) && (IPVERSION == 4)
58 static __inline u_int
59 in_cksum_hdr(const struct ip *ip)
60 {
61 u_int sum = 0;
62
63 __asm(
64 "addl %1, %0\n"
65 "adcl %2, %0\n"
66 "adcl %3, %0\n"
67 "adcl %4, %0\n"
68 "adcl %5, %0\n"
69 "adcl $0, %0"
70 : "+r" (sum)
71 : "g" (((const u_int32_t *)ip)[0]),
72 "g" (((const u_int32_t *)ip)[1]),
73 "g" (((const u_int32_t *)ip)[2]),
74 "g" (((const u_int32_t *)ip)[3]),
75 "g" (((const u_int32_t *)ip)[4])
76 : "cc"
77 );
78 sum = (sum & 0xffff) + (sum >> 16);
79 if (sum > 0xffff)
80 sum -= 0xffff;
81
82 return ~sum & 0xffff;
83 }
84
85 static __inline void
86 in_cksum_update(struct ip *ip)
87 {
88 int __tmpsum;
89 __tmpsum = (int)ntohs(ip->ip_sum) + 256;
90 ip->ip_sum = htons(__tmpsum + (__tmpsum >> 16));
91 }
92 #endif
93
94 static __inline u_short
95 in_addword(u_short sum, u_short b)
96 {
97 __asm(
98 "addw %1, %0\n"
99 "adcw $0, %0"
100 : "+r" (sum)
101 : "g" (b)
102 : "cc"
103 );
104 return (sum);
105 }
106
107 static __inline u_short
108 in_pseudo(u_int sum, u_int b, u_int c)
109 {
110 __asm(
111 "addl %1, %0\n"
112 "adcl %2, %0\n"
113 "adcl $0, %0"
114 : "+r" (sum)
115 : "g" (b),
116 "g" (c)
117 : "cc"
118 );
119 sum = (sum & 0xffff) + (sum >> 16);
120 if (sum > 0xffff)
121 sum -= 0xffff;
122 return (sum);
123 }
124
125 #else
126 #if defined(IPVERSION) && (IPVERSION == 4)
127 #define in_cksum_update(ip) \
128 do { \
129 int __tmpsum; \
130 __tmpsum = (int)ntohs(ip->ip_sum) + 256; \
131 ip->ip_sum = htons(__tmpsum + (__tmpsum >> 16)); \
132 } while(0)
133
134 #endif
135 #endif
136
137 #ifdef _KERNEL
138 #if !defined(__GNUCLIKE_ASM) || defined(__INTEL_COMPILER)
139 #if defined(IPVERSION) && (IPVERSION == 4)
140 u_int in_cksum_hdr(const struct ip *ip);
141 #endif
142 u_short in_addword(u_short sum, u_short b);
143 u_short in_pseudo(u_int sum, u_int b, u_int c);
144 #endif
145 u_short in_cksum_skip(struct mbuf *m, int len, int skip);
146 #endif /* _KERNEL */
147
148 #endif /* _MACHINE_IN_CKSUM_H_ */
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