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1da177e4 LT |
1 | #ifdef __KERNEL__ |
2 | #ifndef _PPC_CHECKSUM_H | |
3 | #define _PPC_CHECKSUM_H | |
4 | ||
5 | ||
6 | /* | |
7 | * computes the checksum of a memory block at buff, length len, | |
8 | * and adds in "sum" (32-bit) | |
9 | * | |
10 | * returns a 32-bit number suitable for feeding into itself | |
11 | * or csum_tcpudp_magic | |
12 | * | |
13 | * this function must be called with even lengths, except | |
14 | * for the last fragment, which may be odd | |
15 | * | |
16 | * it's best to have buff aligned on a 32-bit boundary | |
17 | */ | |
18 | extern unsigned int csum_partial(const unsigned char * buff, int len, | |
19 | unsigned int sum); | |
20 | ||
21 | /* | |
22 | * Computes the checksum of a memory block at src, length len, | |
23 | * and adds in "sum" (32-bit), while copying the block to dst. | |
24 | * If an access exception occurs on src or dst, it stores -EFAULT | |
25 | * to *src_err or *dst_err respectively (if that pointer is not | |
26 | * NULL), and, for an error on src, zeroes the rest of dst. | |
27 | * | |
28 | * Like csum_partial, this must be called with even lengths, | |
29 | * except for the last fragment. | |
30 | */ | |
31 | extern unsigned int csum_partial_copy_generic(const char *src, char *dst, | |
32 | int len, unsigned int sum, | |
33 | int *src_err, int *dst_err); | |
34 | ||
35 | #define csum_partial_copy_from_user(src, dst, len, sum, errp) \ | |
36 | csum_partial_copy_generic((__force void *)(src), (dst), (len), (sum), (errp), NULL) | |
37 | ||
38 | /* FIXME: this needs to be written to really do no check -- Cort */ | |
39 | #define csum_partial_copy_nocheck(src, dst, len, sum) \ | |
40 | csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL) | |
41 | ||
42 | /* | |
43 | * turns a 32-bit partial checksum (e.g. from csum_partial) into a | |
44 | * 1's complement 16-bit checksum. | |
45 | */ | |
46 | static inline unsigned int csum_fold(unsigned int sum) | |
47 | { | |
48 | unsigned int tmp; | |
49 | ||
50 | /* swap the two 16-bit halves of sum */ | |
51 | __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum)); | |
52 | /* if there is a carry from adding the two 16-bit halves, | |
53 | it will carry from the lower half into the upper half, | |
54 | giving us the correct sum in the upper half. */ | |
55 | sum = ~(sum + tmp) >> 16; | |
56 | return sum; | |
57 | } | |
58 | ||
59 | /* | |
60 | * this routine is used for miscellaneous IP-like checksums, mainly | |
61 | * in icmp.c | |
62 | */ | |
63 | static inline unsigned short ip_compute_csum(unsigned char * buff, int len) | |
64 | { | |
65 | return csum_fold(csum_partial(buff, len, 0)); | |
66 | } | |
67 | ||
68 | /* | |
69 | * FIXME: I swiped this one from the sparc and made minor modifications. | |
70 | * It may not be correct. -- Cort | |
71 | */ | |
72 | static inline unsigned long csum_tcpudp_nofold(unsigned long saddr, | |
73 | unsigned long daddr, | |
74 | unsigned short len, | |
75 | unsigned short proto, | |
76 | unsigned int sum) | |
77 | { | |
78 | __asm__("\n\ | |
79 | addc %0,%0,%1 \n\ | |
80 | adde %0,%0,%2 \n\ | |
81 | adde %0,%0,%3 \n\ | |
82 | addze %0,%0 \n\ | |
83 | " | |
84 | : "=r" (sum) | |
85 | : "r" (daddr), "r"(saddr), "r"((proto<<16)+len), "0"(sum)); | |
86 | return sum; | |
87 | } | |
88 | ||
89 | /* | |
90 | * This is a version of ip_compute_csum() optimized for IP headers, | |
91 | * which always checksum on 4 octet boundaries. ihl is the number | |
92 | * of 32-bit words and is always >= 5. | |
93 | */ | |
94 | extern unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl); | |
95 | ||
96 | /* | |
97 | * computes the checksum of the TCP/UDP pseudo-header | |
98 | * returns a 16-bit checksum, already complemented | |
99 | */ | |
100 | extern unsigned short csum_tcpudp_magic(unsigned long saddr, | |
101 | unsigned long daddr, | |
102 | unsigned short len, | |
103 | unsigned short proto, | |
104 | unsigned int sum); | |
105 | ||
106 | #endif | |
107 | #endif /* __KERNEL__ */ |