linux/include/asm-sh64/checksum.h

#ifndef __ASM_SH64_CHECKSUM_H
#define __ASM_SH64_CHECKSUM_H

/*
 * 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.
 *
 * include/asm-sh64/checksum.h
 *
 * Copyright (C) 2000, 2001  Paolo Alberelli
 *
 */

#include <asm/registers.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
 */
asmlinkage unsigned int csum_partial(const unsigned char *buff, int len,
				     unsigned int 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().
 */


unsigned int csum_partial_copy_nocheck(const char *src, char *dst, int len,
				       unsigned int sum);

unsigned int csum_partial_copy_from_user(const char *src, char *dst,
					 int len, int sum, int *err_ptr);

/*
 * These are the old (and unsafe) way of doing checksums, a warning message will be
 * printed if they are used and an exeption occurs.
 *
 * these functions should go away after some time.
 */

#define csum_partial_copy_fromuser csum_partial_copy

unsigned int csum_partial_copy(const char *src, char *dst, int len,
			       unsigned int sum);

static inline unsigned short csum_fold(unsigned int sum)
{
        sum = (sum & 0xffff) + (sum >> 16);
        sum = (sum & 0xffff) + (sum >> 16);
        return ~(sum);
}

unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl);

unsigned long csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr,
				 unsigned short len, unsigned short proto,
				 unsigned int 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));
}

#endif /* __ASM_SH64_CHECKSUM_H */