1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * S390 fast network checksum routines
4 *
5 * S390 version
6 * Copyright IBM Corp. 1999
7 * Author(s): Ulrich Hild (first version)
8 * Martin Schwidefsky (heavily optimized CKSM version)
9 * D.J. Barrow (third attempt)
10 */
11
12 #ifndef _S390_CHECKSUM_H
13 #define _S390_CHECKSUM_H
14
15 #include <linux/instrumented.h>
16 #include <linux/kmsan-checks.h>
17 #include <linux/in6.h>
18
19 static inline __wsum cksm(const void *buff, int len, __wsum sum)
20 {
21 union register_pair rp = {
22 .even = (unsigned long)buff,
23 .odd = (unsigned long)len,
24 };
25
26 instrument_read(buff, len);
27 kmsan_check_memory(buff, len);
28 asm volatile("\n"
29 "0: cksm %[sum],%[rp]\n"
30 " jo 0b\n"
31 : [sum] "+&d" (sum), [rp] "+&d" (rp.pair) : : "cc", "memory");
32 return sum;
33 }
34
35 __wsum csum_partial(const void *buff, int len, __wsum sum);
36
37 #define _HAVE_ARCH_CSUM_AND_COPY
38 __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len);
39
40 /*
41 * Fold a partial checksum without adding pseudo headers.
42 */
43 static inline __sum16 csum_fold(__wsum sum)
44 {
45 u32 csum = (__force u32) sum;
46
47 csum += (csum >> 16) | (csum << 16);
48 csum >>= 16;
49 return (__force __sum16) ~csum;
50 }
51
52 /*
53 * This is a version of ip_compute_csum() optimized for IP headers,
54 * which always checksums on 4 octet boundaries.
55 */
56 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
57 {
58 __u64 csum = 0;
59 __u32 *ptr = (u32 *)iph;
60
61 csum += *ptr++;
62 csum += *ptr++;
63 csum += *ptr++;
64 csum += *ptr++;
65 ihl -= 4;
66 while (ihl--)
67 csum += *ptr++;
68 csum += (csum >> 32) | (csum << 32);
69 return csum_fold((__force __wsum)(csum >> 32));
70 }
71
72 /*
73 * Computes the checksum of the TCP/UDP pseudo-header.
74 * Returns a 32-bit checksum.
75 */
76 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
77 __u8 proto, __wsum sum)
78 {
79 __u64 csum = (__force __u64)sum;
80
81 csum += (__force __u32)saddr;
82 csum += (__force __u32)daddr;
83 csum += len;
84 csum += proto;
85 csum += (csum >> 32) | (csum << 32);
86 return (__force __wsum)(csum >> 32);
87 }
88
89 /*
90 * Computes the checksum of the TCP/UDP pseudo-header.
91 * Returns a 16-bit checksum, already complemented.
92 */
93 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
94 __u8 proto, __wsum sum)
95 {
96 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
97 }
98
99 /*
100 * Used for miscellaneous IP-like checksums, mainly icmp.
101 */
102 static inline __sum16 ip_compute_csum(const void *buff, int len)
103 {
104 return csum_fold(csum_partial(buff, len, 0));
105 }
106
107 #define _HAVE_ARCH_IPV6_CSUM
108 static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
109 const struct in6_addr *daddr,
110 __u32 len, __u8 proto, __wsum csum)
111 {
112 __u64 sum = (__force __u64)csum;
113
114 sum += (__force __u32)saddr->s6_addr32[0];
115 sum += (__force __u32)saddr->s6_addr32[1];
116 sum += (__force __u32)saddr->s6_addr32[2];
117 sum += (__force __u32)saddr->s6_addr32[3];
118 sum += (__force __u32)daddr->s6_addr32[0];
119 sum += (__force __u32)daddr->s6_addr32[1];
120 sum += (__force __u32)daddr->s6_addr32[2];
121 sum += (__force __u32)daddr->s6_addr32[3];
122 sum += len;
123 sum += proto;
124 sum += (sum >> 32) | (sum << 32);
125 return csum_fold((__force __wsum)(sum >> 32));
126 }
127
128 #endif /* _S390_CHECKSUM_H */
129
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