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DEFINITIONS
This source file includes following definitions.
- csum_partial_copy_nocheck
- csum_partial_copy_from_user
- ip_fast_csum
- csum_fold
- csum_tcpudp_nofold
- csum_tcpudp_magic
- ip_compute_csum
- csum_ipv6_magic
- csum_and_copy_to_user
#ifndef ASM_X86__CHECKSUM_32_H
#define ASM_X86__CHECKSUM_32_H
#include <linux/in6.h>
#include <asm/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
*/
asmlinkage __wsum csum_partial(const void *buff, int len, __wsum 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
*/
asmlinkage __wsum csum_partial_copy_generic(const void *src, void *dst,
int len, __wsum sum,
int *src_err_ptr, int *dst_err_ptr);
/*
* 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)
{
return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL);
}
static inline __wsum csum_partial_copy_from_user(const void __user *src,
void *dst,
int len, __wsum sum,
int *err_ptr)
{
might_sleep();
return csum_partial_copy_generic((__force void *)src, dst,
len, sum, err_ptr, NULL);
}
/*
* This is a version of ip_compute_csum() optimized for IP headers,
* which always checksum on 4 octet boundaries.
*
* By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
* Arnt Gulbrandsen.
*/
static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
{
unsigned int sum;
asm volatile("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: ;\n"
/* Since the input registers which are loaded with iph and ihl
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;
}
/*
* Fold a partial checksum
*/
static inline __sum16 csum_fold(__wsum sum)
{
asm("addl %1, %0 ;\n"
"adcl $0xffff, %0 ;\n"
: "=r" (sum)
: "r" ((__force u32)sum << 16),
"0" ((__force u32)sum & 0xffff0000));
return (__force __sum16)(~(__force u32)sum >> 16);
}
static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
unsigned short len,
unsigned short 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,
unsigned short len,
unsigned short proto,
__wsum sum)
{
return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
}
/*
* this routine is used for miscellaneous IP-like checksums, mainly
* in icmp.c
*/
static inline __sum16 ip_compute_csum(const void *buff, int len)
{
return csum_fold(csum_partial(buff, len, 0));
}
#define _HAVE_ARCH_IPV6_CSUM
static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
const struct in6_addr *daddr,
__u32 len, unsigned short proto,
__wsum sum)
{
asm("addl 0(%1), %0 ;\n"
"adcl 4(%1), %0 ;\n"
"adcl 8(%1), %0 ;\n"
"adcl 12(%1), %0 ;\n"
"adcl 0(%2), %0 ;\n"
"adcl 4(%2), %0 ;\n"
"adcl 8(%2), %0 ;\n"
"adcl 12(%2), %0 ;\n"
"adcl %3, %0 ;\n"
"adcl %4, %0 ;\n"
"adcl $0, %0 ;\n"
: "=&r" (sum)
: "r" (saddr), "r" (daddr),
"r" (htonl(len)), "r" (htonl(proto)), "0" (sum));
return csum_fold(sum);
}
/*
* Copy and checksum to user
*/
#define HAVE_CSUM_COPY_USER
static inline __wsum csum_and_copy_to_user(const void *src,
void __user *dst,
int len, __wsum sum,
int *err_ptr)
{
might_sleep();
if (access_ok(VERIFY_WRITE, dst, len))
return csum_partial_copy_generic(src, (__force void *)dst,
len, sum, NULL, err_ptr);
if (len)
*err_ptr = -EFAULT;
return (__force __wsum)-1; /* invalid checksum */
}
#endif /* ASM_X86__CHECKSUM_32_H */