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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 | */ | |
26 | unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum); | |
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 | ||
36 | unsigned int | |
37 | csum_partial_copy_nocheck(const char *src, char *dst, int len, int sum); | |
38 | ||
39 | unsigned int | |
40 | csum_partial_copy_from_user(const char __user *src, char *dst, int len, int sum, int *err_ptr); | |
41 | ||
42 | /* | |
43 | * This is the old (and unsafe) way of doing checksums, a warning message will | |
44 | * be printed if it is used and an exception occurs. | |
45 | * | |
46 | * this functions should go away after some time. | |
47 | */ | |
48 | #define csum_partial_copy(src,dst,len,sum) csum_partial_copy_nocheck(src,dst,len,sum) | |
49 | ||
50 | /* | |
51 | * This is a version of ip_compute_csum() optimized for IP headers, | |
52 | * which always checksum on 4 octet boundaries. | |
53 | */ | |
54 | static inline unsigned short | |
55 | ip_fast_csum(unsigned char * iph, unsigned int ihl) | |
56 | { | |
57 | unsigned int sum, tmp1; | |
58 | ||
59 | __asm__ __volatile__( | |
60 | "ldr %0, [%1], #4 @ ip_fast_csum \n\ | |
61 | ldr %3, [%1], #4 \n\ | |
62 | sub %2, %2, #5 \n\ | |
63 | adds %0, %0, %3 \n\ | |
64 | ldr %3, [%1], #4 \n\ | |
65 | adcs %0, %0, %3 \n\ | |
66 | ldr %3, [%1], #4 \n\ | |
67 | 1: adcs %0, %0, %3 \n\ | |
68 | ldr %3, [%1], #4 \n\ | |
69 | tst %2, #15 @ do this carefully \n\ | |
70 | subne %2, %2, #1 @ without destroying \n\ | |
71 | bne 1b @ the carry flag \n\ | |
72 | adcs %0, %0, %3 \n\ | |
73 | adc %0, %0, #0 \n\ | |
74 | adds %0, %0, %0, lsl #16 \n\ | |
75 | addcs %0, %0, #0x10000 \n\ | |
76 | mvn %0, %0 \n\ | |
77 | mov %0, %0, lsr #16" | |
78 | : "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (tmp1) | |
79 | : "1" (iph), "2" (ihl) | |
80 | : "cc"); | |
81 | return sum; | |
82 | } | |
83 | ||
84 | /* | |
85 | * Fold a partial checksum without adding pseudo headers | |
86 | */ | |
87 | static inline unsigned int | |
88 | csum_fold(unsigned int sum) | |
89 | { | |
90 | __asm__( | |
91 | "adds %0, %1, %1, lsl #16 @ csum_fold \n\ | |
92 | addcs %0, %0, #0x10000" | |
93 | : "=r" (sum) | |
94 | : "r" (sum) | |
95 | : "cc"); | |
96 | return (~sum) >> 16; | |
97 | } | |
98 | ||
99 | static inline unsigned int | |
100 | csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, unsigned short len, | |
101 | unsigned int proto, unsigned int sum) | |
102 | { | |
103 | __asm__( | |
104 | "adds %0, %1, %2 @ csum_tcpudp_nofold \n\ | |
105 | adcs %0, %0, %3 \n\ | |
106 | adcs %0, %0, %4 \n\ | |
107 | adcs %0, %0, %5 \n\ | |
108 | adc %0, %0, #0" | |
109 | : "=&r"(sum) | |
110 | : "r" (sum), "r" (daddr), "r" (saddr), "r" (ntohs(len)), "Ir" (ntohs(proto)) | |
111 | : "cc"); | |
112 | return sum; | |
113 | } | |
114 | /* | |
115 | * computes the checksum of the TCP/UDP pseudo-header | |
116 | * returns a 16-bit checksum, already complemented | |
117 | */ | |
118 | static inline unsigned short int | |
119 | csum_tcpudp_magic(unsigned long saddr, unsigned long daddr, unsigned short len, | |
120 | unsigned int proto, unsigned int sum) | |
121 | { | |
122 | __asm__( | |
123 | "adds %0, %1, %2 @ csum_tcpudp_magic \n\ | |
124 | adcs %0, %0, %3 \n\ | |
125 | adcs %0, %0, %4 \n\ | |
126 | adcs %0, %0, %5 \n\ | |
127 | adc %0, %0, #0 \n\ | |
128 | adds %0, %0, %0, lsl #16 \n\ | |
129 | addcs %0, %0, #0x10000 \n\ | |
130 | mvn %0, %0" | |
131 | : "=&r"(sum) | |
132 | : "r" (sum), "r" (daddr), "r" (saddr), "r" (ntohs(len)), "Ir" (ntohs(proto)) | |
133 | : "cc"); | |
134 | return sum >> 16; | |
135 | } | |
136 | ||
137 | ||
138 | /* | |
139 | * this routine is used for miscellaneous IP-like checksums, mainly | |
140 | * in icmp.c | |
141 | */ | |
142 | static inline unsigned short | |
143 | ip_compute_csum(unsigned char * buff, int len) | |
144 | { | |
145 | return csum_fold(csum_partial(buff, len, 0)); | |
146 | } | |
147 | ||
148 | #define _HAVE_ARCH_IPV6_CSUM | |
149 | extern unsigned long | |
150 | __csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr, __u32 len, | |
151 | __u32 proto, unsigned int sum); | |
152 | ||
153 | static inline unsigned short int | |
154 | csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr, __u32 len, | |
155 | unsigned short proto, unsigned int sum) | |
156 | { | |
157 | return csum_fold(__csum_ipv6_magic(saddr, daddr, htonl(len), | |
158 | htonl(proto), sum)); | |
159 | } | |
160 | #endif |