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/5.3/sys/i386/include/in_cksum.h 128019 2004-04-07 20:46:16Z imp $
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_ */
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