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1da177e4 LT |
1 | /* TODO: csum_tcpudp_magic could be speeded up, and csum_fold as well */ |
2 | ||
3 | #ifndef _CRIS_CHECKSUM_H | |
4 | #define _CRIS_CHECKSUM_H | |
5 | ||
6 | #include <asm/arch/checksum.h> | |
7 | ||
8 | /* | |
9 | * computes the checksum of a memory block at buff, length len, | |
10 | * and adds in "sum" (32-bit) | |
11 | * | |
12 | * returns a 32-bit number suitable for feeding into itself | |
13 | * or csum_tcpudp_magic | |
14 | * | |
15 | * this function must be called with even lengths, except | |
16 | * for the last fragment, which may be odd | |
17 | * | |
18 | * it's best to have buff aligned on a 32-bit boundary | |
19 | */ | |
20 | unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum); | |
21 | ||
22 | /* | |
23 | * the same as csum_partial, but copies from src while it | |
24 | * checksums | |
25 | * | |
26 | * here even more important to align src and dst on a 32-bit (or even | |
27 | * better 64-bit) boundary | |
28 | */ | |
29 | ||
30 | unsigned int csum_partial_copy_nocheck(const char *src, char *dst, | |
31 | int len, unsigned int sum); | |
32 | ||
33 | /* | |
34 | * Fold a partial checksum into a word | |
35 | */ | |
36 | ||
37 | extern inline unsigned int csum_fold(unsigned int sum) | |
38 | { | |
39 | /* the while loop is unnecessary really, it's always enough with two | |
40 | iterations */ | |
41 | ||
42 | while(sum >> 16) | |
43 | sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */ | |
44 | ||
45 | return ~sum; | |
46 | } | |
47 | ||
48 | extern unsigned int csum_partial_copy_from_user(const char *src, char *dst, | |
49 | int len, unsigned int sum, | |
50 | int *errptr); | |
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 | */ | |
57 | ||
58 | extern inline unsigned short ip_fast_csum(unsigned char * iph, | |
59 | unsigned int ihl) | |
60 | { | |
61 | return csum_fold(csum_partial(iph, ihl * 4, 0)); | |
62 | } | |
63 | ||
64 | /* | |
65 | * computes the checksum of the TCP/UDP pseudo-header | |
66 | * returns a 16-bit checksum, already complemented | |
67 | */ | |
68 | ||
69 | extern inline unsigned short int csum_tcpudp_magic(unsigned long saddr, | |
70 | unsigned long daddr, | |
71 | unsigned short len, | |
72 | unsigned short proto, | |
73 | unsigned int sum) | |
74 | { | |
75 | return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum)); | |
76 | } | |
77 | ||
78 | /* | |
79 | * this routine is used for miscellaneous IP-like checksums, mainly | |
80 | * in icmp.c | |
81 | */ | |
82 | ||
83 | extern inline unsigned short ip_compute_csum(unsigned char * buff, int len) { | |
84 | return csum_fold (csum_partial(buff, len, 0)); | |
85 | } | |
86 | ||
87 | #endif |