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 <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 __wsum csum_partial(const void *buff, int len, __wsum 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 __wsum csum_partial_copy_nocheck(const void *src, void *dst,
31 int len, __wsum sum);
32
33 /*
34 * Fold a partial checksum into a word
35 */
36
csum_fold(__wsum csum)37 static inline __sum16 csum_fold(__wsum csum)
38 {
39 u32 sum = (__force u32)csum;
40 sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */
41 sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */
42 return (__force __sum16)~sum;
43 }
44
45 extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
46 int len, __wsum sum,
47 int *errptr);
48
49 /*
50 * This is a version of ip_compute_csum() optimized for IP headers,
51 * which always checksum on 4 octet boundaries.
52 *
53 */
54
ip_fast_csum(const void * iph,unsigned int ihl)55 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
56 {
57 return csum_fold(csum_partial(iph, ihl * 4, 0));
58 }
59
60 /*
61 * computes the checksum of the TCP/UDP pseudo-header
62 * returns a 16-bit checksum, already complemented
63 */
64
csum_tcpudp_magic(__be32 saddr,__be32 daddr,unsigned short len,unsigned short proto,__wsum sum)65 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
66 unsigned short len,
67 unsigned short proto,
68 __wsum sum)
69 {
70 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
71 }
72
73 /*
74 * this routine is used for miscellaneous IP-like checksums, mainly
75 * in icmp.c
76 */
77
ip_compute_csum(const void * buff,int len)78 static inline __sum16 ip_compute_csum(const void *buff, int len)
79 {
80 return csum_fold (csum_partial(buff, len, 0));
81 }
82
83 #endif
84