checksum.h

 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#ifdef CONFIG_64BIT
13
14#define _HAVE_ARCH_IPV6_CSUM
15__sum16 csum_ipv6_magic(const struct in6_addr *saddr,
16			const struct in6_addr *daddr,
17			__u32 len, __u8 proto, __wsum sum);
18
19/*
20 * turns a 32-bit partial checksum (e.g. from csum_partial) into a
21 * 1's complement 16-bit checksum.
22 */
23static inline __sum16 csum_fold(__wsum sum)
24{
25	u32 tmp = (__force u32)sum;
26
27	/*
28	 * swap the two 16-bit halves of sum
29	 * if there is a carry from adding the two 16-bit halves,
30	 * it will carry from the lower half into the upper half,
31	 * giving us the correct sum in the upper half.
32	 */
33	return (__force __sum16)(~(tmp + rol32(tmp, 16)) >> 16);
34}
35#define csum_fold csum_fold
36
37/*
38 * This is a version of ip_compute_csum() optimized for IP headers,
39 * which always checksum on 4 octet boundaries.  ihl is the number
40 * of 32-bit words and is always >= 5.
41 */
42static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
43{
44	u64 sum;
45	__uint128_t tmp;
46	int n = ihl; /* we want it signed */
47
48	tmp = *(const __uint128_t *)iph;
49	iph += 16;
50	n -= 4;
51	tmp += ((tmp >> 64) | (tmp << 64));
52	sum = tmp >> 64;
53	do {
54		sum += *(const u32 *)iph;
55		iph += 4;
56	} while (--n > 0);
57
58	sum += ror64(sum, 32);
59	return csum_fold((__force __wsum)(sum >> 32));
60}
61#define ip_fast_csum ip_fast_csum
62
63extern unsigned int do_csum(const unsigned char *buff, int len);
64#define do_csum do_csum
65
66#endif
67
68#include <asm-generic/checksum.h>
69
70#endif	/* __ASM_CHECKSUM_H */