/*
 * 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.
 *
 * Copyright (C) Equator Technologies
 */
#ifndef _ASM_BSP_CHECKSUM_H_
#define _ASM_BSP_CHECKSUM_H_

/*
 *	This is a version of ip_compute_csum() optimized for IP headers,
 *	which always checksum on 4 octet boundaries.
 */
extern unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl);


/*
 * computes the checksum of the TCP/UDP pseudo-header
 * returns a 16-bit checksum, already complemented
 */
extern unsigned short int csum_tcpudp_magic(unsigned long long saddr,
					   unsigned long long daddr,
					   unsigned short len,
					   unsigned short proto,
					   unsigned int sum);

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

/*
 * 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
 */
extern 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

/*
 * the same as csum_partial, but copies from src while it
 * checksums
 *
 * here even more important to align src and dst on a 32-bit (or even
 * better 64-bit) boundary
 */
unsigned int csum_partial_copy(const char *src, char *dst, int len, unsigned int sum);

/*
 * this routine is used for miscellaneous IP-like checksums, mainly
 * in icmp.c
 */

extern unsigned short ip_compute_csum(unsigned char * buff, int len);

/*
 *	Fold a partial checksum without adding pseudo headers
 */
static inline unsigned short int csum_fold(unsigned int sum)
{
	sum = (sum & 0xffff) + (sum >> 16);
	sum = (sum & 0xffff) + (sum >> 16);
	return ~sum;
}

#endif /* _ASM_BSP_CHECKSUM_H_ */
