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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2016 ARM Ltd.
* Copyright (C) 2023 Loongson Technology Corporation Limited
*/
#ifndef __ASM_CHECKSUM_H
#define __ASM_CHECKSUM_H
#include <linux/bitops.h>
#include <linux/in6.h>
#define _HAVE_ARCH_IPV6_CSUM
__sum16 csum_ipv6_magic(const struct in6_addr *saddr,
const struct in6_addr *daddr,
__u32 len, __u8 proto, __wsum sum);
/*
* turns a 32-bit partial checksum (e.g. from csum_partial) into a
* 1's complement 16-bit checksum.
*/
static inline __sum16 csum_fold(__wsum sum)
{
u32 tmp = (__force u32)sum;
/*
* swap the two 16-bit halves of sum
* if there is a carry from adding the two 16-bit halves,
* it will carry from the lower half into the upper half,
* giving us the correct sum in the upper half.
*/
return (__force __sum16)(~(tmp + rol32(tmp, 16)) >> 16);
}
#define csum_fold csum_fold
/*
* This is a version of ip_compute_csum() optimized for IP headers,
* which always checksum on 4 octet boundaries. ihl is the number
* of 32-bit words and is always >= 5.
*/
static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
{
u64 sum;
__uint128_t tmp;
int n = ihl; /* we want it signed */
tmp = *(const __uint128_t *)iph;
iph += 16;
n -= 4;
tmp += ((tmp >> 64) | (tmp << 64));
sum = tmp >> 64;
do {
sum += *(const u32 *)iph;
iph += 4;
} while (--n > 0);
sum += ror64(sum, 32);
return csum_fold((__force __wsum)(sum >> 32));
}
#define ip_fast_csum ip_fast_csum
extern unsigned int do_csum(const unsigned char *buff, int len);
#define do_csum do_csum
#include <asm-generic/checksum.h>
#endif /* __ASM_CHECKSUM_H */
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