/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* Checksumming functions for IP, TCP, UDP and so on
*
* Authors: Jorge Cwik, <jorge@laser.satlink.net>
* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
* Borrows very liberally from tcp.c and ip.c, see those
* files for more names.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _CHECKSUM_H
#define _CHECKSUM_H
#include <linux/errno.h>
#include <asm/types.h>
#include <asm/byteorder.h>
#include <asm/uaccess.h>
#include <asm/checksum.h>
#ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
static inline
unsigned int csum_and_copy_from_user (const unsigned char __user *src, unsigned char *dst,
int len, int sum, int *err_ptr)
{
if (access_ok(VERIFY_READ, src, len))
return csum_partial_copy_from_user(src, dst, len, sum, err_ptr);
if (len)
*err_ptr = -EFAULT;
return sum;
}
#endif
#ifndef HAVE_CSUM_COPY_USER
static __inline__ unsigned int csum_and_copy_to_user
(const unsigned char *src, unsigned char __user *dst, int len, unsigned int sum, int *err_ptr)
{
sum = csum_partial(src, len, sum);
if (access_ok(VERIFY_WRITE, dst, len)) {
if (copy_to_user(dst, src, len) == 0)
return sum;
}
if (len)
*err_ptr = -EFAULT;
return -1; /* invalid checksum */
}
#endif
static inline unsigned int csum_add(unsigned int csum, unsigned int addend)
{
csum += addend;
return csum + (csum < addend);
}
static inline unsigned int csum_sub(unsigned int csum, unsigned int addend)
{
return csum_add(csum, ~addend);
}
static inline unsigned int
csum_block_add(unsigned int csum, unsigned int csum2, int offset)
{
if (offset&1)
csum2 = ((csum2&0xFF00FF)<<8)+((csum2>>8)&0xFF00FF);
return csum_add(csum, csum2);
}
static inline unsigned int
csum_block_sub(unsigned int csum, unsigned int csum2, int offset)
{
if (offset&1)
csum2 = ((csum2&0xFF00FF)<<8)+((csum2>>8)&0xFF00FF);
return csum_sub(csum, csum2);
}
#endif
