1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* TODO: csum_tcpudp_magic could be speeded up, and csum_fold as well */
3
4 #ifndef _CRIS_CHECKSUM_H
5 #define _CRIS_CHECKSUM_H
6
7 #include <arch/checksum.h>
8
9 /*
10 * computes the checksum of a memory block at buff, length len,
11 * and adds in "sum" (32-bit)
12 *
13 * returns a 32-bit number suitable for feeding into itself
14 * or csum_tcpudp_magic
15 *
16 * this function must be called with even lengths, except
17 * for the last fragment, which may be odd
18 *
19 * it's best to have buff aligned on a 32-bit boundary
20 */
21 __wsum csum_partial(const void *buff, int len, __wsum sum);
22
23 /*
24 * the same as csum_partial, but copies from src while it
25 * checksums
26 *
27 * here even more important to align src and dst on a 32-bit (or even
28 * better 64-bit) boundary
29 */
30
31 __wsum csum_partial_copy_nocheck(const void *src, void *dst,
32 int len, __wsum sum);
33
34 /*
35 * Fold a partial checksum into a word
36 */
37
csum_fold(__wsum csum)38 static inline __sum16 csum_fold(__wsum csum)
39 {
40 u32 sum = (__force u32)csum;
41 sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */
42 sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */
43 return (__force __sum16)~sum;
44 }
45
46 extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
47 int len, __wsum sum,
48 int *errptr);
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 */
55
ip_fast_csum(const void * iph,unsigned int ihl)56 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
57 {
58 return csum_fold(csum_partial(iph, ihl * 4, 0));
59 }
60
61 /*
62 * computes the checksum of the TCP/UDP pseudo-header
63 * returns a 16-bit checksum, already complemented
64 */
65
csum_tcpudp_magic(__be32 saddr,__be32 daddr,__u32 len,__u8 proto,__wsum sum)66 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
67 __u32 len, __u8 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