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/* $Id: checksum.h,v 1.6 1998/09/19 19:19:36 ralf Exp $
*
* 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 by Ralf Baechle
*/
#ifndef __ASM_MIPS_CHECKSUM_H
#define __ASM_MIPS_CHECKSUM_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);
#define HAVE_CSUM_COPY_USER
unsigned int csum_and_copy_to_user (const char *src, char *dst,
int len, int sum, int *err_ptr);
/*
* 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* this is obsolete and will go away.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 noat
sll $1,%0,16
addu %0,$1
sltu $1,%0,$1
srl %0,%0,16
addu %0,$1
xori %0,0xffff
.set at"
: "=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 noreorder
.set noat
lw %0,(%1)
subu %2,4
#blez %2,2f
sll %2,2 # delay slot
lw %3,4(%1)
addu %2,%1 # delay slot
addu %0,%3
sltu $1,%0,%3
lw %3,8(%1)
addu %0,$1
addu %0,%3
sltu $1,%0,%3
lw %3,12(%1)
addu %0,$1
addu %0,%3
sltu $1,%0,%3
addu %0,$1
1: lw %3,16(%1)
addiu %1,4
addu %0,%3
sltu $1,%0,%3
bne %2,%1,1b
addu %0,$1 # delay slot
2: .set at
.set reorder"
: "=&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 noat
addu %0,%2
sltu $1,%0,%2
addu %0,$1
addu %0,%3
sltu $1,%0,%3
addu %0,$1
addu %0,%4
sltu $1,%0,%4
addu %0,$1
.set at"
: "=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,
__u16 len,
unsigned short proto,
unsigned int sum)
{
__asm__("
.set noreorder
.set noat
addu %0,%5 # proto (long in network byte order)
sltu $1,%0,%5
addu %0,$1
addu %0,%6 # csum
sltu $1,%0,%6
lw %1,0(%2) # four words source address
addu %0,$1
addu %0,%1
sltu $1,%0,$1
lw %1,4(%2)
addu %0,$1
addu %0,%1
sltu $1,%0,$1
lw %1,8(%2)
addu %0,$1
addu %0,%1
sltu $1,%0,$1
lw %1,12(%2)
addu %0,$1
addu %0,%1
sltu $1,%0,$1
lw %1,0(%3)
addu %0,$1
addu %0,%1
sltu $1,%0,$1
lw %1,4(%3)
addu %0,$1
addu %0,%1
sltu $1,%0,$1
lw %1,8(%3)
addu %0,$1
addu %0,%1
sltu $1,%0,$1
lw %1,12(%3)
addu %0,$1
addu %0,%1
sltu $1,%0,$1
.set noat
.set noreorder"
: "=r" (sum),
"=r" (proto)
: "r" (saddr),
"r" (daddr),
"0" (htonl((__u32) (len))),
"1" (htonl(proto)),
"r"(sum)
: "$1");
return csum_fold(sum);
}
#endif /* __ASM_MIPS_CHECKSUM_H */
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