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1/* checksum.h: FRV checksumming
2 *
3 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#ifndef _ASM_CHECKSUM_H
13#define _ASM_CHECKSUM_H
14
15#include <linux/in6.h>
16
17/*
18 * computes the checksum of a memory block at buff, length len,
19 * and adds in "sum" (32-bit)
20 *
21 * returns a 32-bit number suitable for feeding into itself
22 * or csum_tcpudp_magic
23 *
24 * this function must be called with even lengths, except
25 * for the last fragment, which may be odd
26 *
27 * it's best to have buff aligned on a 32-bit boundary
28 */
29unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum);
30
31/*
32 * the same as csum_partial, but copies from src while it
33 * checksums
34 *
35 * here even more important to align src and dst on a 32-bit (or even
36 * better 64-bit) boundary
37 */
38unsigned int csum_partial_copy(const char *src, char *dst, int len, int sum);
39
40/*
41 * the same as csum_partial_copy, but copies from user space.
42 *
43 * here even more important to align src and dst on a 32-bit (or even
44 * better 64-bit) boundary
45 */
46extern unsigned int csum_partial_copy_from_user(const char *src, char *dst,
47 int len, int sum, int *csum_err);
48
49#define csum_partial_copy_nocheck(src, dst, len, sum) \
50 csum_partial_copy((src), (dst), (len), (sum))
51
52/*
53 * This is a version of ip_compute_csum() optimized for IP headers,
54 * which always checksum on 4 octet boundaries.
55 *
56 */
57static inline
58unsigned short ip_fast_csum(unsigned char *iph, unsigned int ihl)
59{
60 unsigned int tmp, inc, sum = 0;
61
62 asm(" addcc gr0,gr0,gr0,icc0\n" /* clear icc0.C */
63 " subi %1,#4,%1 \n"
64 "0: \n"
65 " ldu.p @(%1,%3),%4 \n"
66 " subicc %2,#1,%2,icc1 \n"
67 " addxcc.p %4,%0,%0,icc0 \n"
68 " bhi icc1,#2,0b \n"
69
70 /* fold the 33-bit result into 16-bits */
71 " addxcc gr0,%0,%0,icc0 \n"
72 " srli %0,#16,%1 \n"
73 " sethi #0,%0 \n"
74 " add %1,%0,%0 \n"
75 " srli %0,#16,%1 \n"
76 " add %1,%0,%0 \n"
77
78 : "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (inc), "=&r"(tmp)
79 : "0" (sum), "1" (iph), "2" (ihl), "3" (4),
80 "m"(*(volatile struct { int _[100]; } *)iph)
81 : "icc0", "icc1"
82 );
83
84 return ~sum;
85}
86
87/*
88 * Fold a partial checksum
89 */
90static inline unsigned int csum_fold(unsigned int sum)
91{
92 unsigned int tmp;
93
94 asm(" srli %0,#16,%1 \n"
95 " sethi #0,%0 \n"
96 " add %1,%0,%0 \n"
97 " srli %0,#16,%1 \n"
98 " add %1,%0,%0 \n"
99 : "=r"(sum), "=&r"(tmp)
100 : "0"(sum)
101 );
102
103 return ~sum;
104}
105
106/*
107 * computes the checksum of the TCP/UDP pseudo-header
108 * returns a 16-bit checksum, already complemented
109 */
110static inline unsigned int
111csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, unsigned short len,
112 unsigned short proto, unsigned int sum)
113{
114 asm(" addcc %1,%0,%0,icc0 \n"
115 " addxcc %2,%0,%0,icc0 \n"
116 " addxcc %3,%0,%0,icc0 \n"
117 " addxcc gr0,%0,%0,icc0 \n"
118 : "=r" (sum)
119 : "r" (daddr), "r" (saddr), "r" (len + proto), "0"(sum)
120 : "icc0"
121 );
122 return sum;
123}
124
125static inline unsigned short int
126csum_tcpudp_magic(unsigned long saddr, unsigned long daddr, unsigned short len,
127 unsigned short proto, unsigned int sum)
128{
129 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
130}
131
132/*
133 * this routine is used for miscellaneous IP-like checksums, mainly
134 * in icmp.c
135 */
136extern unsigned short ip_compute_csum(const unsigned char * buff, int len);
137
138#define _HAVE_ARCH_IPV6_CSUM
139static inline unsigned short int
140csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr,
141 __u32 len, unsigned short proto, unsigned int sum)
142{
143 unsigned long tmp, tmp2;
144
145 asm(" addcc %2,%0,%0,icc0 \n"
146
147 /* add up the source addr */
148 " ldi @(%3,0),%1 \n"
149 " addxcc %1,%0,%0,icc0 \n"
150 " ldi @(%3,4),%2 \n"
151 " addxcc %2,%0,%0,icc0 \n"
152 " ldi @(%3,8),%1 \n"
153 " addxcc %1,%0,%0,icc0 \n"
154 " ldi @(%3,12),%2 \n"
155 " addxcc %2,%0,%0,icc0 \n"
156
157 /* add up the dest addr */
158 " ldi @(%4,0),%1 \n"
159 " addxcc %1,%0,%0,icc0 \n"
160 " ldi @(%4,4),%2 \n"
161 " addxcc %2,%0,%0,icc0 \n"
162 " ldi @(%4,8),%1 \n"
163 " addxcc %1,%0,%0,icc0 \n"
164 " ldi @(%4,12),%2 \n"
165 " addxcc %2,%0,%0,icc0 \n"
166
167 /* fold the 33-bit result into 16-bits */
168 " addxcc gr0,%0,%0,icc0 \n"
169 " srli %0,#16,%1 \n"
170 " sethi #0,%0 \n"
171 " add %1,%0,%0 \n"
172 " srli %0,#16,%1 \n"
173 " add %1,%0,%0 \n"
174
175 : "=r" (sum), "=&r" (tmp), "=r" (tmp2)
176 : "r" (saddr), "r" (daddr), "0" (sum), "2" (len + proto)
177 : "icc0"
178 );
179
180 return ~sum;
181}
182
183#endif /* _ASM_CHECKSUM_H */