1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2016 ARM Ltd.
4 * Copyright (C) 2023 Loongson Technology Corporation Limited
5 */
6#ifndef __ASM_CHECKSUM_H
7#define __ASM_CHECKSUM_H
8
9#include <linux/bitops.h>
10#include <linux/in6.h>
11
12#define _HAVE_ARCH_IPV6_CSUM
13__sum16 csum_ipv6_magic(const struct in6_addr *saddr,
14			const struct in6_addr *daddr,
15			__u32 len, __u8 proto, __wsum sum);
16
17/*
18 * turns a 32-bit partial checksum (e.g. from csum_partial) into a
19 * 1's complement 16-bit checksum.
20 */
21static inline __sum16 csum_fold(__wsum sum)
22{
23	u32 tmp = (__force u32)sum;
24
25	/*
26	 * swap the two 16-bit halves of sum
27	 * if there is a carry from adding the two 16-bit halves,
28	 * it will carry from the lower half into the upper half,
29	 * giving us the correct sum in the upper half.
30	 */
31	return (__force __sum16)(~(tmp + rol32(tmp, 16)) >> 16);
32}
33#define csum_fold csum_fold
34
35/*
36 * This is a version of ip_compute_csum() optimized for IP headers,
37 * which always checksum on 4 octet boundaries.  ihl is the number
38 * of 32-bit words and is always >= 5.
39 */
40static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
41{
42	u64 sum;
43	__uint128_t tmp;
44	int n = ihl; /* we want it signed */
45
46	tmp = *(const __uint128_t *)iph;
47	iph += 16;
48	n -= 4;
49	tmp += ((tmp >> 64) | (tmp << 64));
50	sum = tmp >> 64;
51	do {
52		sum += *(const u32 *)iph;
53		iph += 4;
54	} while (--n > 0);
55
56	sum += ror64(sum, 32);
57	return csum_fold((__force __wsum)(sum >> 32));
58}
59#define ip_fast_csum ip_fast_csum
60
61extern unsigned int do_csum(const unsigned char *buff, int len);
62#define do_csum do_csum
63
64#include <asm-generic/checksum.h>
65
66#endif	/* __ASM_CHECKSUM_H */
67