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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* Checksumming functions for IP, TCP, UDP and so on
*
* Authors: Jorge Cwik, <jorge@laser.satlink.net>
* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
* Borrows very liberally from tcp.c and ip.c, see those
* files for more names.
*/
#ifndef _CHECKSUM_H
#define _CHECKSUM_H
#include <linux/errno.h>
#include <asm/types.h>
#include <asm/byteorder.h>
#include <linux/uaccess.h>
#include <asm/checksum.h>
#ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
static __always_inline
__wsum csum_and_copy_from_user (const void __user *src, void *dst,
int len)
{
if (copy_from_user(dst, src, len))
return 0;
return csum_partial(dst, len, ~0U);
}
#endif
#ifndef HAVE_CSUM_COPY_USER
static __always_inline __wsum csum_and_copy_to_user
(const void *src, void __user *dst, int len)
{
__wsum sum = csum_partial(src, len, ~0U);
if (copy_to_user(dst, src, len) == 0)
return sum;
return 0;
}
#endif
#ifndef _HAVE_ARCH_CSUM_AND_COPY
static __always_inline __wsum
csum_partial_copy_nocheck(const void *src, void *dst, int len)
{
memcpy(dst, src, len);
return csum_partial(dst, len, 0);
}
#endif
#ifndef HAVE_ARCH_CSUM_ADD
static __always_inline __wsum csum_add(__wsum csum, __wsum addend)
{
u32 res = (__force u32)csum;
res += (__force u32)addend;
return (__force __wsum)(res + (res < (__force u32)addend));
}
#endif
static __always_inline __wsum csum_sub(__wsum csum, __wsum addend)
{
return csum_add(csum, ~addend);
}
static __always_inline __sum16 csum16_add(__sum16 csum, __be16 addend)
{
u16 res = (__force u16)csum;
res += (__force u16)addend;
return (__force __sum16)(res + (res < (__force u16)addend));
}
static __always_inline __sum16 csum16_sub(__sum16 csum, __be16 addend)
{
return csum16_add(csum, ~addend);
}
static __always_inline __wsum csum_shift(__wsum sum, int offset)
{
/* rotate sum to align it with a 16b boundary */
if (offset & 1)
return (__force __wsum)ror32((__force u32)sum, 8);
return sum;
}
static __always_inline __wsum
csum_block_add(__wsum csum, __wsum csum2, int offset)
{
return csum_add(csum, csum_shift(csum2, offset));
}
static __always_inline __wsum
csum_block_add_ext(__wsum csum, __wsum csum2, int offset, int len)
{
return csum_block_add(csum, csum2, offset);
}
static __always_inline __wsum
csum_block_sub(__wsum csum, __wsum csum2, int offset)
{
return csum_block_add(csum, ~csum2, offset);
}
static __always_inline __wsum csum_unfold(__sum16 n)
{
return (__force __wsum)n;
}
static __always_inline
__wsum csum_partial_ext(const void *buff, int len, __wsum sum)
{
return csum_partial(buff, len, sum);
}
#define CSUM_MANGLED_0 ((__force __sum16)0xffff)
static __always_inline void csum_replace_by_diff(__sum16 *sum, __wsum diff)
{
*sum = csum_fold(csum_add(diff, ~csum_unfold(*sum)));
}
static __always_inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to)
{
__wsum tmp = csum_sub(~csum_unfold(*sum), (__force __wsum)from);
*sum = csum_fold(csum_add(tmp, (__force __wsum)to));
}
/* Implements RFC 1624 (Incremental Internet Checksum)
* 3. Discussion states :
* HC' = ~(~HC + ~m + m')
* m : old value of a 16bit field
* m' : new value of a 16bit field
*/
static __always_inline void csum_replace2(__sum16 *sum, __be16 old, __be16 new)
{
*sum = ~csum16_add(csum16_sub(~(*sum), old), new);
}
static inline void csum_replace(__wsum *csum, __wsum old, __wsum new)
{
*csum = csum_add(csum_sub(*csum, old), new);
}
struct sk_buff;
void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
__be32 from, __be32 to, bool pseudohdr);
void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
const __be32 *from, const __be32 *to,
bool pseudohdr);
void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb,
__wsum diff, bool pseudohdr);
static __always_inline
void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb,
__be16 from, __be16 to, bool pseudohdr)
{
inet_proto_csum_replace4(sum, skb, (__force __be32)from,
(__force __be32)to, pseudohdr);
}
static __always_inline __wsum remcsum_adjust(void *ptr, __wsum csum,
int start, int offset)
{
__sum16 *psum = (__sum16 *)(ptr + offset);
__wsum delta;
/* Subtract out checksum up to start */
csum = csum_sub(csum, csum_partial(ptr, start, 0));
/* Set derived checksum in packet */
delta = csum_sub((__force __wsum)csum_fold(csum),
(__force __wsum)*psum);
*psum = csum_fold(csum);
return delta;
}
static __always_inline void remcsum_unadjust(__sum16 *psum, __wsum delta)
{
*psum = csum_fold(csum_sub(delta, (__force __wsum)*psum));
}
#endif
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