Subversion Repositories or1k

#ifndef _OR32_CHECKSUM_H
#define _OR32_CHECKSUM_H
 
#include <linux/config.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
 */
unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum);
 
/*
 * the same as csum_partial_copy, 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, int sum);
 
 
/*
 * the same as csum_partial_copy, but copies from user space.
 *
 * here even more important to align src and dst on a 32-bit (or even
 * better 64-bit) boundary
 */
 
unsigned int csum_partial_copy_fromuser(const char *src, char *dst, int len, int sum);
 
unsigned short ip_fast_csum(unsigned char *iph, unsigned int ihl);
 
/*
 *	Fold a partial checksum without adding pseudo headers
 */
 
static inline unsigned short 
csum_fold(unsigned int sum)
{
	sum = (sum & 0xffff) + (sum >> 16);
	sum = (sum & 0xffff) + (sum >> 16);
	return ~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)
{
	unsigned long result = saddr;
 
	result += daddr;
	result += (daddr > result);
 
	result += len;
	result += (len > result);
 
	result += proto;
	result += (proto > result);
 
	result += sum;
        result += (sum > result);
 
	result = (result >> 16) + (result & 0xffff);
	result = (result >> 16) + (result & 0xffff);
 
	return ~result;
}
 
extern unsigned short
ip_compute_csum(const unsigned char * buff, int len);
 
#endif /* _OR32_CHECKSUM_H */