/* TODO: csum_tcpudp_magic could be speeded up, and csum_fold as well */

#ifndef _CRIS_CHECKSUM_H
#define _CRIS_CHECKSUM_H

#include <arch/checksum.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
*/
__wsum csum_partial(const void *buff, int len, __wsum sum);

/*
* 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
*/

__wsum csum_partial_copy_nocheck(const void *src, void *dst,
int len, __wsum sum);

/*
* Fold a partial checksum into a word
*/

static inline __sum16 csum_fold(__wsum csum)
{
u32 sum = (__force u32)csum;
sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */
sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */
return (__force __sum16)~sum;
}

extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
int len, __wsum sum,
int *errptr);

/*
* This is a version of ip_compute_csum() optimized for IP headers,
* which always checksum on 4 octet boundaries.
*
*/

static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
{
return csum_fold(csum_partial(iph, ihl * 4, 0));
}

/*
* computes the checksum of the TCP/UDP pseudo-header
* returns a 16-bit checksum, already complemented
*/

static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
unsigned short len,
unsigned short proto,
__wsum 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 __sum16 ip_compute_csum(const void *buff, int len)
{
return csum_fold (csum_partial(buff, len, 0));
}

#endif