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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __UM_CHECKSUM_H
#define __UM_CHECKSUM_H
#include <linux/string.h>
#include <linux/in6.h>
#include <linux/uaccess.h>
/*
* computes the checksum of a memory block at buff, length len,
* and adds in "sum" (32-bit)
*
* returns a 32-bit number suitable for feeding into itself
* or csum_tcpudp_magic
*
* this function must be called with even lengths, except
* for the last fragment, which may be odd
*
* it's best to have buff aligned on a 32-bit boundary
*/
extern __wsum csum_partial(const void *buff, int len, __wsum sum);
/*
* Note: when you get a NULL pointer exception here this means someone
* passed in an incorrect kernel address to one of these functions.
*
* If you use these functions directly please don't forget the
* access_ok().
*/
static __inline__
__wsum csum_partial_copy_nocheck(const void *src, void *dst,
int len, __wsum sum)
{
memcpy(dst, src, len);
return csum_partial(dst, len, sum);
}
/*
* the same as csum_partial, but copies from src while it
* checksums, and handles user-space pointer exceptions correctly, when needed.
*
* here even more important to align src and dst on a 32-bit (or even
* better 64-bit) boundary
*/
static __inline__
__wsum csum_partial_copy_from_user(const void __user *src, void *dst,
int len, __wsum sum, int *err_ptr)
{
if (copy_from_user(dst, src, len)) {
*err_ptr = -EFAULT;
return (__force __wsum)-1;
}
return csum_partial(dst, len, sum);
}
/**
* 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)
{
__asm__(
" addl %1,%0\n"
" adcl $0xffff,%0"
: "=r" (sum)
: "r" ((__force u32)sum << 16),
"0" ((__force u32)sum & 0xffff0000)
);
return (__force __sum16)(~(__force u32)sum >> 16);
}
/**
* 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)
{
asm(" addl %1, %0\n"
" adcl %2, %0\n"
" adcl %3, %0\n"
" adcl $0, %0\n"
: "=r" (sum)
: "g" (daddr), "g" (saddr), "g" ((len + proto) << 8), "0" (sum));
return sum;
}
/*
* computes the checksum of the TCP/UDP pseudo-header
* returns a 16-bit checksum, already complemented
*/
static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
__u32 len, __u8 proto,
__wsum sum)
{
return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
}
/**
* 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)
{
unsigned int sum;
asm( " movl (%1), %0\n"
" subl $4, %2\n"
" jbe 2f\n"
" addl 4(%1), %0\n"
" adcl 8(%1), %0\n"
" adcl 12(%1), %0\n"
"1: adcl 16(%1), %0\n"
" lea 4(%1), %1\n"
" decl %2\n"
" jne 1b\n"
" adcl $0, %0\n"
" movl %0, %2\n"
" shrl $16, %0\n"
" addw %w2, %w0\n"
" adcl $0, %0\n"
" notl %0\n"
"2:"
/* Since the input registers which are loaded with iph and ipl
are modified, we must also specify them as outputs, or gcc
will assume they contain their original values. */
: "=r" (sum), "=r" (iph), "=r" (ihl)
: "1" (iph), "2" (ihl)
: "memory");
return (__force __sum16)sum;
}
#ifdef CONFIG_X86_32
# include "checksum_32.h"
#else
# include "checksum_64.h"
#endif
#endif
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