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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, 1996, 1997, 1998, 2001 by Ralf Baechle
*/
#ifndef _ASM_CHECKSUM_H
#define _ASM_CHECKSUM_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.
*/
#define csum_partial_copy_nocheck csum_partial_copy
/*
* 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 char *src, char *dst, int len,
unsigned int sum, int *errp);
/*
* Copy and checksum to user
*/
#define HAVE_CSUM_COPY_USER
extern inline unsigned int csum_and_copy_to_user (const char *src, char *dst,
int len, int sum,
int *err_ptr)
{
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)
*
* this is obsolete and will go away.
*/
#define csum_partial_copy_fromuser csum_partial_copy
unsigned int csum_partial_copy(const char *src, 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\tnoat\t\t\t# csum_fold\n\t"
"sll\t$1,%0,16\n\t"
"addu\t%0,$1\n\t"
"sltu\t$1,%0,$1\n\t"
"srl\t%0,%0,16\n\t"
"addu\t%0,$1\n\t"
"xori\t%0,0xffff\n\t"
".set\tat"
: "=r" (sum)
: "0" (sum)
: "$1");
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 sum;
unsigned long dummy;
/*
* This is for 32-bit MIPS processors.
*/
__asm__ __volatile__(
".set\tnoreorder\t\t\t# ip_fast_csum\n\t"
".set\tnoat\n\t"
"lw\t%0, (%1)\n\t"
"subu\t%2, 4\n\t"
"#blez\t%2, 2f\n\t"
" sll\t%2, 2\n\t"
"lw\t%3, 4(%1)\n\t"
"addu\t%2, %1\n\t"
"addu\t%0, %3\n\t"
"sltu\t$1, %0, %3\n\t"
"lw\t%3, 8(%1)\n\t"
"addu\t%0, $1\n\t"
"addu\t%0, %3\n\t"
"sltu\t$1, %0, %3\n\t"
"lw\t%3, 12(%1)\n\t"
"addu\t%0, $1\n\t"
"addu\t%0, %3\n\t"
"sltu\t$1, %0, %3\n\t"
"addu\t%0, $1\n"
"1:\tlw\t%3, 16(%1)\n\t"
"addiu\t%1, 4\n\t"
"addu\t%0, %3\n\t"
"sltu\t$1, %0, %3\n\t"
"bne\t%2, %1, 1b\n\t"
" addu\t%0, $1\n"
"2:\t.set\tat\n\t"
".set\treorder"
: "=&r" (sum), "=&r" (iph), "=&r" (ihl), "=&r" (dummy)
: "1" (iph), "2" (ihl)
: "$1");
return csum_fold(sum);
}
/*
* computes the checksum of the TCP/UDP pseudo-header
* returns a 16-bit checksum, already complemented
*/
static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
unsigned long daddr,
unsigned short len,
unsigned short proto,
unsigned int sum)
{
__asm__(
".set\tnoat\t\t\t# csum_tcpudp_nofold\n\t"
"addu\t%0, %2\n\t"
"sltu\t$1, %0, %2\n\t"
"addu\t%0, $1\n\t"
"addu\t%0, %3\n\t"
"sltu\t$1, %0, %3\n\t"
"addu\t%0, $1\n\t"
"addu\t%0, %4\n\t"
"sltu\t$1, %0, %4\n\t"
"addu\t%0, $1\n\t"
".set\tat"
: "=r" (sum)
: "0" (daddr), "r"(saddr),
#ifdef __MIPSEL__
"r" ((ntohs(len)<<16)+proto*256),
#else
"r" (((proto)<<16)+len),
#endif
"r" (sum)
: "$1");
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\tnoreorder\t\t\t# csum_ipv6_magic\n\t"
".set\tnoat\n\t"
"addu\t%0, %5\t\t\t# proto (long in network byte order)\n\t"
"sltu\t$1, %0, %5\n\t"
"addu\t%0, $1\n\t"
"addu\t%0, %6\t\t\t# csum\n\t"
"sltu\t$1, %0, %6\n\t"
"lw\t%1, 0(%2)\t\t\t# four words source address\n\t"
"addu\t%0, $1\n\t"
"addu\t%0, %1\n\t"
"sltu\t$1, %0, $1\n\t"
"lw\t%1, 4(%2)\n\t"
"addu\t%0, $1\n\t"
"addu\t%0, %1\n\t"
"sltu\t$1, %0, $1\n\t"
"lw\t%1, 8(%2)\n\t"
"addu\t%0, $1\n\t"
"addu\t%0, %1\n\t"
"sltu\t$1, %0, $1\n\t"
"lw\t%1, 12(%2)\n\t"
"addu\t%0, $1\n\t"
"addu\t%0, %1\n\t"
"sltu\t$1, %0, $1\n\t"
"lw\t%1, 0(%3)\n\t"
"addu\t%0, $1\n\t"
"addu\t%0, %1\n\t"
"sltu\t$1, %0, $1\n\t"
"lw\t%1, 4(%3)\n\t"
"addu\t%0, $1\n\t"
"addu\t%0, %1\n\t"
"sltu\t$1, %0, $1\n\t"
"lw\t%1, 8(%3)\n\t"
"addu\t%0, $1\n\t"
"addu\t%0, %1\n\t"
"sltu\t$1, %0, $1\n\t"
"lw\t%1, 12(%3)\n\t"
"addu\t%0, $1\n\t"
"addu\t%0, %1\n\t"
"sltu\t$1, %0, $1\n\t"
".set\tnoat\n\t"
".set\tnoreorder"
: "=r" (sum), "=r" (proto)
: "r" (saddr), "r" (daddr),
"0" (htonl(len)), "1" (htonl(proto)), "r" (sum)
: "$1");
return csum_fold(sum);
}
#endif /* _ASM_CHECKSUM_H */
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