1 #ifndef _METAG_CHECKSUM_H
2 #define _METAG_CHECKSUM_H
3
4 /*
5 * computes the checksum of a memory block at buff, length len,
6 * and adds in "sum" (32-bit)
7 *
8 * returns a 32-bit number suitable for feeding into itself
9 * or csum_tcpudp_magic
10 *
11 * this function must be called with even lengths, except
12 * for the last fragment, which may be odd
13 *
14 * it's best to have buff aligned on a 32-bit boundary
15 */
16 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
17
18 /*
19 * the same as csum_partial, but copies from src while it
20 * checksums
21 *
22 * here even more important to align src and dst on a 32-bit (or even
23 * better 64-bit) boundary
24 */
25 extern __wsum csum_partial_copy(const void *src, void *dst, int len,
26 __wsum sum);
27
28 /*
29 * the same as csum_partial_copy, but copies from user space.
30 *
31 * here even more important to align src and dst on a 32-bit (or even
32 * better 64-bit) boundary
33 */
34 extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
35 int len, __wsum sum, int *csum_err);
36
37 #define csum_partial_copy_nocheck(src, dst, len, sum) \
38 csum_partial_copy((src), (dst), (len), (sum))
39
40 /*
41 * Fold a partial checksum
42 */
csum_fold(__wsum csum)43 static inline __sum16 csum_fold(__wsum csum)
44 {
45 u32 sum = (__force u32)csum;
46 sum = (sum & 0xffff) + (sum >> 16);
47 sum = (sum & 0xffff) + (sum >> 16);
48 return (__force __sum16)~sum;
49 }
50
51 /*
52 * This is a version of ip_compute_csum() optimized for IP headers,
53 * which always checksum on 4 octet boundaries.
54 */
55 extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
56
57 /*
58 * computes the checksum of the TCP/UDP pseudo-header
59 * returns a 16-bit checksum, already complemented
60 */
csum_tcpudp_nofold(__be32 saddr,__be32 daddr,unsigned short len,unsigned short proto,__wsum sum)61 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
62 unsigned short len,
63 unsigned short proto,
64 __wsum sum)
65 {
66 unsigned long len_proto = (proto + len) << 8;
67 asm ("ADD %0, %0, %1\n"
68 "ADDS %0, %0, %2\n"
69 "ADDCS %0, %0, #1\n"
70 "ADDS %0, %0, %3\n"
71 "ADDCS %0, %0, #1\n"
72 : "=d" (sum)
73 : "d" (daddr), "d" (saddr), "d" (len_proto),
74 "0" (sum)
75 : "cc");
76 return sum;
77 }
78
79 static inline __sum16
csum_tcpudp_magic(__be32 saddr,__be32 daddr,unsigned short len,unsigned short proto,__wsum sum)80 csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len,
81 unsigned short proto, __wsum sum)
82 {
83 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
84 }
85
86 /*
87 * this routine is used for miscellaneous IP-like checksums, mainly
88 * in icmp.c
89 */
90 extern __sum16 ip_compute_csum(const void *buff, int len);
91
92 #endif /* _METAG_CHECKSUM_H */
93