linux/arch/x86/include/asm/checksum_64.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_CHECKSUM_64_H
#define _ASM_X86_CHECKSUM_64_H

/*
 * Checksums for x86-64
 * Copyright 2002 by Andi Kleen, SuSE Labs
 * with some code from asm-x86/checksum.h
 */

#include <linux/compiler.h>
#include <asm/byteorder.h>

/**
 * csum_fold - Fold and invert a 32bit checksum.
 * sum: 32bit unfolded sum
 *
 * Fold a 32bit running checksum to 16bit and invert it. This is usually
 * the last step before putting a checksum into a packet.
 * Make sure not to mix with 64bit checksums.
 */
static inline __sum16 csum_fold(__wsum sum)
{ … }

/*
 *	This is a version of ip_compute_csum() optimized for IP headers,
 *	which always checksum on 4 octet boundaries.
 *
 *	By Jorge Cwik <[email protected]>, adapted for linux by
 *	Arnt Gulbrandsen.
 */

/**
 * ip_fast_csum - Compute the IPv4 header checksum efficiently.
 * iph: ipv4 header
 * ihl: length of header / 4
 */
static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
{ … }

/**
 * csum_tcpup_nofold - Compute an IPv4 pseudo header checksum.
 * @saddr: source address
 * @daddr: destination address
 * @len: length of packet
 * @proto: ip protocol of packet
 * @sum: initial sum to be added in (32bit unfolded)
 *
 * Returns the pseudo header checksum the input data. Result is
 * 32bit unfolded.
 */
static inline __wsum
csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
		   __u8 proto, __wsum sum)
{ … }


/**
 * csum_tcpup_magic - Compute an IPv4 pseudo header checksum.
 * @saddr: source address
 * @daddr: destination address
 * @len: length of packet
 * @proto: ip protocol of packet
 * @sum: initial sum to be added in (32bit unfolded)
 *
 * Returns the 16bit pseudo header checksum the input data already
 * complemented and ready to be filled in.
 */
static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
					__u32 len, __u8 proto,
					__wsum sum)
{ … }

/**
 * csum_partial - Compute an internet checksum.
 * @buff: buffer to be checksummed
 * @len: length of buffer.
 * @sum: initial sum to be added in (32bit unfolded)
 *
 * Returns the 32bit unfolded internet checksum of the buffer.
 * Before filling it in it needs to be csum_fold()'ed.
 * buff should be aligned to a 64bit boundary if possible.
 */
extern __wsum csum_partial(const void *buff, int len, __wsum sum);

/* Do not call this directly. Use the wrappers below */
extern __visible __wsum csum_partial_copy_generic(const void *src, void *dst, int len);

extern __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len);
extern __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len);
extern __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len);

/**
 * ip_compute_csum - Compute an 16bit IP checksum.
 * @buff: buffer address.
 * @len: length of buffer.
 *
 * Returns the 16bit folded/inverted checksum of the passed buffer.
 * Ready to fill in.
 */
extern __sum16 ip_compute_csum(const void *buff, int len);

/**
 * csum_ipv6_magic - Compute checksum of an IPv6 pseudo header.
 * @saddr: source address
 * @daddr: destination address
 * @len: length of packet
 * @proto: protocol of packet
 * @sum: initial sum (32bit unfolded) to be added in
 *
 * Computes an IPv6 pseudo header checksum. This sum is added the checksum
 * into UDP/TCP packets and contains some link layer information.
 * Returns the unfolded 32bit checksum.
 */

struct in6_addr;

#define _HAVE_ARCH_IPV6_CSUM …
extern __sum16
csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr,
		__u32 len, __u8 proto, __wsum sum);

static inline unsigned add32_with_carry(unsigned a, unsigned b)
{ … }

#define HAVE_ARCH_CSUM_ADD
static inline __wsum csum_add(__wsum csum, __wsum addend)
{ … }

#endif /* _ASM_X86_CHECKSUM_64_H */