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