/* * INET		An implementation of the TCP/IP protocol suite for the LINUX *		operating system.  INET is implemented using the  BSD Socket *		interface as the means of communication with the user level. * *		Checksumming functions for IP, TCP, UDP and so on * * Authors:	Jorge Cwik, <jorge@laser.satlink.net> *		Arnt Gulbrandsen, <agulbra@nvg.unit.no> *		Borrows very liberally from tcp.c and ip.c, see those *		files for more names. * *		This program is free software; you can redistribute it and/or *		modify it under the terms of the GNU General Public License *		as published by the Free Software Foundation; either version *		2 of the License, or (at your option) any later version. */ #ifndef _CHECKSUM_H#define _CHECKSUM_H #include <linux/errno.h>#include <asm/types.h>#include <asm/byteorder.h>#include <asm/uaccess.h>#include <asm/checksum.h> #ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USERstatic inlineunsigned int csum_and_copy_from_user (const unsigned char __user *src, unsigned char *dst,				      int len, int sum, int *err_ptr){	if (access_ok(VERIFY_READ, src, len))		return csum_partial_copy_from_user(src, dst, len, sum, err_ptr); 	if (len)		*err_ptr = -EFAULT; 	return sum;}#endif #ifndef HAVE_CSUM_COPY_USERstatic __inline__ unsigned int csum_and_copy_to_user(const unsigned char *src, unsigned char __user *dst, int len, unsigned int sum, int *err_ptr){	sum = csum_partial(src, len, sum); 	if (access_ok(VERIFY_WRITE, dst, len)) {		if (copy_to_user(dst, src, len) == 0)			return sum;	}	if (len)		*err_ptr = -EFAULT; 	return -1; /* invalid checksum */}#endif static inline unsigned int csum_add(unsigned int csum, unsigned int addend){	csum += addend;	return csum + (csum < addend);} static inline unsigned int csum_sub(unsigned int csum, unsigned int addend){	return csum_add(csum, ~addend);} static inline unsigned intcsum_block_add(unsigned int csum, unsigned int csum2, int offset){	if (offset&1)		csum2 = ((csum2&0xFF00FF)<<8)+((csum2>>8)&0xFF00FF);	return csum_add(csum, csum2);} static inline unsigned intcsum_block_sub(unsigned int csum, unsigned int csum2, int offset){	if (offset&1)		csum2 = ((csum2&0xFF00FF)<<8)+((csum2>>8)&0xFF00FF);	return csum_sub(csum, csum2);} #endif