/* * 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 inline__wsum csum_and_copy_from_user (const void __user *src, void *dst,				      int len, __wsum 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__ __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len, __wsum 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 (__force __wsum)-1; /* invalid checksum */}#endif static inline __wsum csum_add(__wsum csum, __wsum addend){	u32 res = (__force u32)csum;	res += (__force u32)addend;	return (__force __wsum)(res + (res < (__force u32)addend));} static inline __wsum csum_sub(__wsum csum, __wsum addend){	return csum_add(csum, ~addend);} static inline __wsumcsum_block_add(__wsum csum, __wsum csum2, int offset){	u32 sum = (__force u32)csum2;	if (offset&1)		sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF);	return csum_add(csum, (__force __wsum)sum);} static inline __wsumcsum_block_sub(__wsum csum, __wsum csum2, int offset){	u32 sum = (__force u32)csum2;	if (offset&1)		sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF);	return csum_sub(csum, (__force __wsum)sum);} static inline __wsum csum_unfold(__sum16 n){	return (__force __wsum)n;} #define CSUM_MANGLED_0 ((__force __sum16)0xffff) static inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to){	__be32 diff[] = { ~from, to }; 	*sum = csum_fold(csum_partial(diff, sizeof(diff), ~csum_unfold(*sum)));} static inline void csum_replace2(__sum16 *sum, __be16 from, __be16 to){	csum_replace4(sum, (__force __be32)from, (__force __be32)to);} struct sk_buff;extern void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,				     __be32 from, __be32 to, int pseudohdr); static inline void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb,					    __be16 from, __be16 to,					    int pseudohdr){	inet_proto_csum_replace4(sum, skb, (__force __be32)from,				 (__force __be32)to, pseudohdr);} #endif