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/*
* 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.
*/
/*
* Fixes:
*
* Ralf Baechle : generic ipv6 checksum
* <ralf@waldorf-gmbh.de>
*/
#ifndef _CHECKSUM_H
#define _CHECKSUM_H
#include <asm/types.h>
#include <asm/byteorder.h>
#include <net/ip.h>
#include <asm/uaccess.h>
#include <asm/checksum.h>
#ifndef _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 csum)
{
int carry;
__u32 ulen;
__u32 uproto;
csum += saddr->s6_addr32[0];
carry = (csum < saddr->s6_addr32[0]);
csum += carry;
csum += saddr->s6_addr32[1];
carry = (csum < saddr->s6_addr32[1]);
csum += carry;
csum += saddr->s6_addr32[2];
carry = (csum < saddr->s6_addr32[2]);
csum += carry;
csum += saddr->s6_addr32[3];
carry = (csum < saddr->s6_addr32[3]);
csum += carry;
csum += daddr->s6_addr32[0];
carry = (csum < daddr->s6_addr32[0]);
csum += carry;
csum += daddr->s6_addr32[1];
carry = (csum < daddr->s6_addr32[1]);
csum += carry;
csum += daddr->s6_addr32[2];
carry = (csum < daddr->s6_addr32[2]);
csum += carry;
csum += daddr->s6_addr32[3];
carry = (csum < daddr->s6_addr32[3]);
csum += carry;
ulen = htonl((__u32) len);
csum += ulen;
carry = (csum < ulen);
csum += carry;
uproto = htonl(proto);
csum += uproto;
carry = (csum < uproto);
csum += carry;
return csum_fold(csum);
}
#endif
#ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
static inline
unsigned int csum_and_copy_from_user (const char *src, char *dst,
int len, int sum, int *err_ptr)
{
if (verify_area(VERIFY_READ, src, len) == 0)
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 char *src, char *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
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