/* TODO: csum_tcpudp_magic could be speeded up, and csum_fold as well */
#ifndef _CRIS_CHECKSUM_H
#define _CRIS_CHECKSUM_H
#include
/*
* 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
*/
unsigned int csum_partial(const unsigned char * buff, int len, unsigned int 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
*/
unsigned int csum_partial_copy_nocheck(const char *src, char *dst,
int len, unsigned int sum);
/*
* Fold a partial checksum into a word
*/
extern inline unsigned int csum_fold(unsigned int sum)
{
/* the while loop is unnecessary really, it's always enough with two
iterations */
while(sum >> 16)
sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */
return ~sum;
}
extern unsigned int csum_partial_copy_from_user(const char *src, char *dst,
int len, unsigned int sum,
int *errptr);
/*
* This is a version of ip_compute_csum() optimized for IP headers,
* which always checksum on 4 octet boundaries.
*
*/
extern inline unsigned short ip_fast_csum(unsigned char * 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
*/
extern 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
*/
extern inline unsigned short ip_compute_csum(unsigned char * buff, int len) {
return csum_fold (csum_partial(buff, len, 0));
}
#endif