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/*
* Licensed under the GPL
*/
#ifndef __UM_SYSDEP_CHECKSUM_H
#define __UM_SYSDEP_CHECKSUM_H
#include "linux/string.h"
#include "linux/in6.h"
#include "asm/uaccess.h"
extern unsigned csum_partial(const unsigned char *buff, unsigned len,
unsigned 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__
unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst,
int len, int sum)
{
memcpy(dst, src, len);
return(csum_partial(dst, len, sum));
}
static __inline__
unsigned int csum_partial_copy_from_user(const unsigned char *src,
unsigned char *dst, int len, int sum,
int *err_ptr)
{
if(copy_from_user(dst, src, len)){
*err_ptr = -EFAULT;
return(-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 unsigned int csum_fold(unsigned int sum)
{
__asm__(
" addl %1,%0\n"
" adcl $0xffff,%0"
: "=r" (sum)
: "r" (sum << 16), "0" (sum & 0xffff0000)
);
return (~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 unsigned long
csum_tcpudp_nofold(unsigned saddr, unsigned daddr, unsigned short len,
unsigned short proto, unsigned int 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" ((ntohs(len)<<16)+proto*256), "0" (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));
}
/**
* ip_fast_csum - Compute the IPv4 header checksum efficiently.
* iph: ipv4 header
* ihl: length of header / 4
*/
static inline unsigned short ip_fast_csum(unsigned char *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(sum);
}
static inline unsigned add32_with_carry(unsigned a, unsigned b)
{
asm("addl %2,%0\n\t"
"adcl $0,%0"
: "=r" (a)
: "0" (a), "r" (b));
return a;
}
extern unsigned short ip_compute_csum(unsigned char * buff, int len);
#endif
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