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1da177e4 LT |
1 | /* |
2 | * linux/include/asm-arm/checksum.h | |
3 | * | |
4 | * IP checksum routines | |
5 | * | |
6 | * Copyright (C) Original authors of ../asm-i386/checksum.h | |
7 | * Copyright (C) 1996-1999 Russell King | |
8 | */ | |
9 | #ifndef __ASM_ARM_CHECKSUM_H | |
10 | #define __ASM_ARM_CHECKSUM_H | |
11 | ||
12 | #include <linux/in6.h> | |
13 | ||
14 | /* | |
15 | * computes the checksum of a memory block at buff, length len, | |
16 | * and adds in "sum" (32-bit) | |
17 | * | |
18 | * returns a 32-bit number suitable for feeding into itself | |
19 | * or csum_tcpudp_magic | |
20 | * | |
21 | * this function must be called with even lengths, except | |
22 | * for the last fragment, which may be odd | |
23 | * | |
24 | * it's best to have buff aligned on a 32-bit boundary | |
25 | */ | |
0ffb7122 | 26 | __wsum csum_partial(const void *buff, int len, __wsum sum); |
1da177e4 LT |
27 | |
28 | /* | |
29 | * the same as csum_partial, but copies from src while it | |
30 | * checksums, and handles user-space pointer exceptions correctly, when needed. | |
31 | * | |
32 | * here even more important to align src and dst on a 32-bit (or even | |
33 | * better 64-bit) boundary | |
34 | */ | |
35 | ||
0ffb7122 AV |
36 | __wsum |
37 | csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum); | |
1da177e4 | 38 | |
0ffb7122 AV |
39 | __wsum |
40 | csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *err_ptr); | |
1da177e4 LT |
41 | |
42 | /* | |
43 | * This is a version of ip_compute_csum() optimized for IP headers, | |
44 | * which always checksum on 4 octet boundaries. | |
45 | */ | |
0ffb7122 AV |
46 | static inline __sum16 |
47 | ip_fast_csum(const void *iph, unsigned int ihl) | |
1da177e4 LT |
48 | { |
49 | unsigned int sum, tmp1; | |
50 | ||
51 | __asm__ __volatile__( | |
52 | "ldr %0, [%1], #4 @ ip_fast_csum \n\ | |
53 | ldr %3, [%1], #4 \n\ | |
54 | sub %2, %2, #5 \n\ | |
55 | adds %0, %0, %3 \n\ | |
56 | ldr %3, [%1], #4 \n\ | |
57 | adcs %0, %0, %3 \n\ | |
58 | ldr %3, [%1], #4 \n\ | |
59 | 1: adcs %0, %0, %3 \n\ | |
60 | ldr %3, [%1], #4 \n\ | |
61 | tst %2, #15 @ do this carefully \n\ | |
62 | subne %2, %2, #1 @ without destroying \n\ | |
63 | bne 1b @ the carry flag \n\ | |
64 | adcs %0, %0, %3 \n\ | |
65 | adc %0, %0, #0 \n\ | |
66 | adds %0, %0, %0, lsl #16 \n\ | |
67 | addcs %0, %0, #0x10000 \n\ | |
68 | mvn %0, %0 \n\ | |
69 | mov %0, %0, lsr #16" | |
70 | : "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (tmp1) | |
71 | : "1" (iph), "2" (ihl) | |
72 | : "cc"); | |
0ffb7122 | 73 | return (__force __sum16)sum; |
1da177e4 LT |
74 | } |
75 | ||
76 | /* | |
77 | * Fold a partial checksum without adding pseudo headers | |
78 | */ | |
0ffb7122 | 79 | static inline __sum16 csum_fold(__wsum sum) |
1da177e4 LT |
80 | { |
81 | __asm__( | |
82 | "adds %0, %1, %1, lsl #16 @ csum_fold \n\ | |
83 | addcs %0, %0, #0x10000" | |
84 | : "=r" (sum) | |
85 | : "r" (sum) | |
86 | : "cc"); | |
0ffb7122 | 87 | return (__force __sum16)(~(__force u32)sum >> 16); |
1da177e4 LT |
88 | } |
89 | ||
0ffb7122 AV |
90 | static inline __wsum |
91 | csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len, | |
92 | unsigned short proto, __wsum sum) | |
1da177e4 LT |
93 | { |
94 | __asm__( | |
95 | "adds %0, %1, %2 @ csum_tcpudp_nofold \n\ | |
96 | adcs %0, %0, %3 \n\ | |
97 | adcs %0, %0, %4 \n\ | |
98 | adcs %0, %0, %5 \n\ | |
99 | adc %0, %0, #0" | |
100 | : "=&r"(sum) | |
0ffb7122 | 101 | : "r" (sum), "r" (daddr), "r" (saddr), "r" (htons(len)), "Ir" (htons(proto)) |
1da177e4 LT |
102 | : "cc"); |
103 | return sum; | |
104 | } | |
105 | /* | |
106 | * computes the checksum of the TCP/UDP pseudo-header | |
107 | * returns a 16-bit checksum, already complemented | |
108 | */ | |
0ffb7122 AV |
109 | static inline __sum16 |
110 | csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len, | |
111 | unsigned short proto, __wsum sum) | |
1da177e4 LT |
112 | { |
113 | __asm__( | |
114 | "adds %0, %1, %2 @ csum_tcpudp_magic \n\ | |
115 | adcs %0, %0, %3 \n\ | |
116 | adcs %0, %0, %4 \n\ | |
117 | adcs %0, %0, %5 \n\ | |
118 | adc %0, %0, #0 \n\ | |
119 | adds %0, %0, %0, lsl #16 \n\ | |
120 | addcs %0, %0, #0x10000 \n\ | |
121 | mvn %0, %0" | |
122 | : "=&r"(sum) | |
0ffb7122 | 123 | : "r" (sum), "r" (daddr), "r" (saddr), "r" (htons(len)), "Ir" (htons(proto)) |
1da177e4 | 124 | : "cc"); |
0ffb7122 | 125 | return (__force __sum16)((__force u32)sum >> 16); |
1da177e4 LT |
126 | } |
127 | ||
128 | ||
129 | /* | |
130 | * this routine is used for miscellaneous IP-like checksums, mainly | |
131 | * in icmp.c | |
132 | */ | |
0ffb7122 AV |
133 | static inline __sum16 |
134 | ip_compute_csum(const void *buff, int len) | |
1da177e4 LT |
135 | { |
136 | return csum_fold(csum_partial(buff, len, 0)); | |
137 | } | |
138 | ||
139 | #define _HAVE_ARCH_IPV6_CSUM | |
0ffb7122 AV |
140 | extern __wsum |
141 | __csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, __be32 len, | |
142 | __be32 proto, __wsum sum); | |
1da177e4 | 143 | |
0ffb7122 AV |
144 | static inline __sum16 |
145 | csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr, __u32 len, | |
146 | unsigned short proto, __wsum sum) | |
1da177e4 LT |
147 | { |
148 | return csum_fold(__csum_ipv6_magic(saddr, daddr, htonl(len), | |
149 | htonl(proto), sum)); | |
150 | } | |
151 | #endif |