#ifndef _I386_CHECKSUM_H#define _I386_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 */asmlinkage 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, and handles user-space pointer exceptions correctly, when needed. * * here even more important to align src and dst on a 32-bit (or even * better 64-bit) boundary */asmlinkage unsigned int csum_partial_copy_generic( const char *src, char *dst, int len, int sum,						   int *src_err_ptr, int *dst_err_ptr);/* *	Note: when you get a NULL pointer exception here this means someone *	passed in an incorrect kernel address to one of these functions.  *	 *	If you use these functions directly please don't forget the  *	verify_area(). */static __inline__unsigned int csum_partial_copy_nocheck ( const char *src, char *dst,					int len, int sum){	return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL);}static __inline__unsigned int csum_partial_copy_from_user ( const char *src, char *dst,						int len, int sum, int *err_ptr){	return csum_partial_copy_generic ( src, dst, len, sum, err_ptr, NULL);}/* * These are the old (and unsafe) way of doing checksums, a warning message will be * printed if they are used and an exeption occurs. * * these functions should go away after some time. */#define csum_partial_copy_fromuser csum_partial_copyunsigned int csum_partial_copy( const char *src, char *dst, int len, int sum);/* *	This is a version of ip_compute_csum() optimized for IP headers, *	which always checksum on 4 octet boundaries. * *	By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by *	Arnt Gulbrandsen. */static inline unsigned short ip_fast_csum(unsigned char * iph,					  unsigned int ihl) {	unsigned int sum;	__asm__ __volatile__("	    movl (%1), %0	    subl $4, %2	    jbe 2f	    addl 4(%1), %0	    adcl 8(%1), %0	    adcl 12(%1), %01:	    adcl 16(%1), %0	    lea 4(%1), %1	    decl %2	    jne	1b	    adcl $0, %0	    movl %0, %2	    shrl $16, %0	    addw %w2, %w0	    adcl $0, %0	    notl %02:	    "	/* Since the input registers which are loaded with iph and ipl	   are modified, we must also specify them as outputs, or gcc	   will assume they contain their original values. */	: "=r" (sum), "=r" (iph), "=r" (ihl)	: "1" (iph), "2" (ihl));	return(sum);}/* *	Fold a partial checksum */static inline unsigned int csum_fold(unsigned int sum){	__asm__("		addl %1, %0		adcl $0xffff, %0		"		: "=r" (sum)		: "r" (sum << 16), "0" (sum & 0xffff0000)	);	return (~sum) >> 16;} static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,						   unsigned long daddr,						   unsigned short len,						   unsigned short proto,						   unsigned int sum) {    __asm__("	addl %1, %0	adcl %2, %0	adcl %3, %0	adcl $0, %0	"	: "=r" (sum)	: "g" (daddr), "g"(saddr), "g"((ntohs(len)<<16)+proto*256), "0"(sum));    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) {	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 unsigned short ip_compute_csum(unsigned char * buff, int len) {    return csum_fold (csum_partial(buff, len, 0));}#define _HAVE_ARCH_IPV6_CSUMstatic __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,						     struct in6_addr *daddr,						     __u32 len,						     unsigned short proto,						     unsigned int sum) {	__asm__("		addl 0(%1), %0		adcl 4(%1), %0		adcl 8(%1), %0		adcl 12(%1), %0		adcl 0(%2), %0		adcl 4(%2), %0		adcl 8(%2), %0		adcl 12(%2), %0		adcl %3, %0		adcl %4, %0		adcl $0, %0		"		: "=&r" (sum)		: "r" (saddr), "r" (daddr), 		  "r"(htonl(len)), "r"(htonl(proto)), "0"(sum));	return csum_fold(sum);}/*  *	Copy and checksum to user */#define HAVE_CSUM_COPY_USERstatic __inline__ unsigned int csum_and_copy_to_user (const char *src, char *dst,				    int len, int sum, int *err_ptr){	if (access_ok(VERIFY_WRITE, dst, len))		return csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr);	if (len)		*err_ptr = -EFAULT;	return -1; /* invalid checksum */}#endif