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/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1995, 96, 97, 98, 99, 2001 by Ralf Baechle
* Copyright (C) 1999 Silicon Graphics, Inc.
* Copyright (C) 2001 Thiemo Seufer.
* Copyright (C) 2002 Maciej W. Rozycki
*/
#ifndef _ASM_CHECKSUM_H
#define _ASM_CHECKSUM_H
#include <linux/config.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
*/
unsigned int csum_partial(const unsigned char *buff, int len, unsigned int sum);
/*
* this is a new version of the above that records errors it finds in *errp,
* but continues and zeros the rest of the buffer.
*/
unsigned int csum_partial_copy_from_user(const unsigned char __user *src,
unsigned char *dst, int len,
unsigned int sum, int *errp);
/*
* Copy and checksum to user
*/
#define HAVE_CSUM_COPY_USER
static inline unsigned int csum_and_copy_to_user (const unsigned char *src,
unsigned char __user *dst,
int len, int sum,
int *err_ptr)
{
might_sleep();
sum = csum_partial(src, len, sum);
if (copy_to_user(dst, src, len)) {
*err_ptr = -EFAULT;
return -1;
}
return sum;
}
/*
* the same as csum_partial, but copies from user space (but on MIPS
* we have just one address space, so this is identical to the above)
*/
unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst,
int len, unsigned int sum);
/*
* Fold a partial checksum without adding pseudo headers
*/
static inline unsigned short int csum_fold(unsigned int sum)
{
__asm__(
" .set push # csum_fold\n"
" .set noat \n"
" sll $1, %0, 16 \n"
" addu %0, $1 \n"
" sltu $1, %0, $1 \n"
" srl %0, %0, 16 \n"
" addu %0, $1 \n"
" xori %0, 0xffff \n"
" .set pop"
: "=r" (sum)
: "0" (sum));
return sum;
}
/*
* 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 unsigned short ip_fast_csum(unsigned char *iph, unsigned int ihl)
{
unsigned int *word = (unsigned int *) iph;
unsigned int *stop = word + ihl;
unsigned int csum;
int carry;
csum = word[0];
csum += word[1];
carry = (csum < word[1]);
csum += carry;
csum += word[2];
carry = (csum < word[2]);
csum += carry;
csum += word[3];
carry = (csum < word[3]);
csum += carry;
word += 4;
do {
csum += *word;
carry = (csum < *word);
csum += carry;
word++;
} while (word != stop);
return csum_fold(csum);
}
static inline unsigned int csum_tcpudp_nofold(unsigned long saddr,
unsigned long daddr, unsigned short len, unsigned short proto,
unsigned int sum)
{
__asm__(
" .set push # csum_tcpudp_nofold\n"
" .set noat \n"
#ifdef CONFIG_32BIT
" addu %0, %2 \n"
" sltu $1, %0, %2 \n"
" addu %0, $1 \n"
" addu %0, %3 \n"
" sltu $1, %0, %3 \n"
" addu %0, $1 \n"
" addu %0, %4 \n"
" sltu $1, %0, %4 \n"
" addu %0, $1 \n"
#endif
#ifdef CONFIG_64BIT
" daddu %0, %2 \n"
" daddu %0, %3 \n"
" daddu %0, %4 \n"
" dsll32 $1, %0, 0 \n"
" daddu %0, $1 \n"
" dsra32 %0, %0, 0 \n"
#endif
" .set pop"
: "=r" (sum)
: "0" (daddr), "r"(saddr),
#ifdef __MIPSEL__
"r" (((unsigned long)htons(len)<<16) + proto*256),
#else
"r" (((unsigned long)(proto)<<16) + len),
#endif
"r" (sum));
return sum;
}
/*
* computes the checksum of the TCP/UDP pseudo-header
* returns a 16-bit checksum, already complemented
*/
static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
unsigned long daddr,
unsigned short len,
unsigned short proto,
unsigned int 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 unsigned short ip_compute_csum(unsigned char * buff, int len)
{
return csum_fold(csum_partial(buff, len, 0));
}
#define _HAVE_ARCH_IPV6_CSUM
static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
struct in6_addr *daddr,
__u32 len,
unsigned short proto,
unsigned int sum)
{
__asm__(
" .set push # csum_ipv6_magic\n"
" .set noreorder \n"
" .set noat \n"
" addu %0, %5 # proto (long in network byte order)\n"
" sltu $1, %0, %5 \n"
" addu %0, $1 \n"
" addu %0, %6 # csum\n"
" sltu $1, %0, %6 \n"
" lw %1, 0(%2) # four words source address\n"
" addu %0, $1 \n"
" addu %0, %1 \n"
" sltu $1, %0, %1 \n"
" lw %1, 4(%2) \n"
" addu %0, $1 \n"
" addu %0, %1 \n"
" sltu $1, %0, %1 \n"
" lw %1, 8(%2) \n"
" addu %0, $1 \n"
" addu %0, %1 \n"
" sltu $1, %0, %1 \n"
" lw %1, 12(%2) \n"
" addu %0, $1 \n"
" addu %0, %1 \n"
" sltu $1, %0, %1 \n"
" lw %1, 0(%3) \n"
" addu %0, $1 \n"
" addu %0, %1 \n"
" sltu $1, %0, %1 \n"
" lw %1, 4(%3) \n"
" addu %0, $1 \n"
" addu %0, %1 \n"
" sltu $1, %0, %1 \n"
" lw %1, 8(%3) \n"
" addu %0, $1 \n"
" addu %0, %1 \n"
" sltu $1, %0, %1 \n"
" lw %1, 12(%3) \n"
" addu %0, $1 \n"
" addu %0, %1 \n"
" sltu $1, %0, %1 \n"
" addu %0, $1 # Add final carry\n"
" .set pop"
: "=r" (sum), "=r" (proto)
: "r" (saddr), "r" (daddr),
"0" (htonl(len)), "1" (htonl(proto)), "r" (sum));
return csum_fold(sum);
}
#endif /* _ASM_CHECKSUM_H */
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