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 * $FreeBSD: releng/5.1/sys/i386/include/in_cksum.h 98648 2002-06-22 22:35:53Z jdp $
37 */
38
39 #ifndef _MACHINE_IN_CKSUM_H_
40 #define _MACHINE_IN_CKSUM_H_ 1
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 #ifdef __GNUC__
57 static __inline u_int
58 in_cksum_hdr(const struct ip *ip)
59 {
60 register u_int sum = 0;
61
62 /* __volatile is necessary here because the condition codes are used. */
63 #define ADD(n) __asm __volatile ("addl %1, %0" : "+r" (sum) : \
64 "g" (((const u_int32_t *)ip)[n / 4]))
65 #define ADDC(n) __asm __volatile ("adcl %1, %0" : "+r" (sum) : \
66 "g" (((const u_int32_t *)ip)[n / 4]))
67 #define MOP __asm __volatile ("adcl $0, %0" : "+r" (sum))
68
69 ADD(0);
70 ADDC(4);
71 ADDC(8);
72 ADDC(12);
73 ADDC(16);
74 MOP;
75 #undef ADD
76 #undef ADDC
77 #undef MOP
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
93 static __inline u_short
94 in_addword(u_short sum, u_short b)
95 {
96 /* __volatile is necessary because the condition codes are used. */
97 __asm __volatile ("addw %1, %0" : "+r" (sum) : "r" (b));
98 __asm __volatile ("adcw $0, %0" : "+r" (sum));
99
100 return (sum);
101 }
102
103 static __inline u_short
104 in_pseudo(u_int sum, u_int b, u_int c)
105 {
106 /* __volatile is necessary because the condition codes are used. */
107 __asm __volatile ("addl %1, %0" : "+r" (sum) : "g" (b));
108 __asm __volatile ("adcl %1, %0" : "+r" (sum) : "g" (c));
109 __asm __volatile ("adcl $0, %0" : "+r" (sum));
110
111 sum = (sum & 0xffff) + (sum >> 16);
112 if (sum > 0xffff)
113 sum -= 0xffff;
114 return (sum);
115 }
116
117 #else
118 u_int in_cksum_hdr(const struct ip *);
119 #define in_cksum_update(ip) \
120 do { \
121 int __tmpsum; \
122 __tmpsum = (int)ntohs(ip->ip_sum) + 256; \
123 ip->ip_sum = htons(__tmpsum + (__tmpsum >> 16)); \
124 } while(0)
125
126 #endif
127
128 #ifdef _KERNEL
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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