WebSVN - shark - Blame - Rev 1618 - /shark/branches/xen/drivers/linuxc26/include/asm/checksum.h

Rev	Author	Line No.	Line
422	giacomo	1	#ifndef _I386_CHECKSUM_H
		2	#define _I386_CHECKSUM_H
		3
		4	#include <linux/in6.h>
		5
		6	/*
		7	* computes the checksum of a memory block at buff, length len,
		8	* and adds in "sum" (32-bit)
		9	*
		10	* returns a 32-bit number suitable for feeding into itself
		11	* or csum_tcpudp_magic
		12	*
		13	* this function must be called with even lengths, except
		14	* for the last fragment, which may be odd
		15	*
		16	* it's best to have buff aligned on a 32-bit boundary
		17	*/
		18	asmlinkage unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum);
		19
		20	/*
		21	* the same as csum_partial, but copies from src while it
		22	* checksums, and handles user-space pointer exceptions correctly, when needed.
		23	*
		24	* here even more important to align src and dst on a 32-bit (or even
		25	* better 64-bit) boundary
		26	*/
		27
		28	asmlinkage unsigned int csum_partial_copy_generic( const char src, char dst, int len, int sum,
		29	int src_err_ptr, int dst_err_ptr);
		30
		31	/*
		32	* Note: when you get a NULL pointer exception here this means someone
		33	* passed in an incorrect kernel address to one of these functions.
		34	*
		35	* If you use these functions directly please don't forget the
		36	* verify_area().
		37	*/
		38	static __inline__
		39	unsigned int csum_partial_copy_nocheck ( const char src, char dst,
		40	int len, int sum)
		41	{
		42	return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL);
		43	}
		44
		45	static __inline__
		46	unsigned int csum_partial_copy_from_user ( const char src, char dst,
		47	int len, int sum, int *err_ptr)
		48	{
		49	return csum_partial_copy_generic ( src, dst, len, sum, err_ptr, NULL);
		50	}
		51
		52	/*
		53	* This is a version of ip_compute_csum() optimized for IP headers,
		54	* which always checksum on 4 octet boundaries.
		55	*
		56	* By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
		57	* Arnt Gulbrandsen.
		58	*/
		59	static inline unsigned short ip_fast_csum(unsigned char * iph,
		60	unsigned int ihl)
		61	{
		62	unsigned int sum;
		63
		64	__asm__ __volatile__(
		65	"movl (%1), %0 ;\n"
		66	"subl $4, %2 ;\n"
		67	"jbe 2f ;\n"
		68	"addl 4(%1), %0 ;\n"
		69	"adcl 8(%1), %0 ;\n"
		70	"adcl 12(%1), %0 ;\n"
		71	"1: adcl 16(%1), %0 ;\n"
		72	"lea 4(%1), %1 ;\n"
		73	"decl %2 ;\n"
		74	"jne 1b ;\n"
		75	"adcl $0, %0 ;\n"
		76	"movl %0, %2 ;\n"
		77	"shrl $16, %0 ;\n"
		78	"addw %w2, %w0 ;\n"
		79	"adcl $0, %0 ;\n"
		80	"notl %0 ;\n"
		81	"2: ;\n"
		82	/* Since the input registers which are loaded with iph and ipl
		83	are modified, we must also specify them as outputs, or gcc
		84	will assume they contain their original values. */
		85	: "=r" (sum), "=r" (iph), "=r" (ihl)
		86	: "1" (iph), "2" (ihl)
		87	: "memory");
		88	return(sum);
		89	}
		90
		91	/*
		92	* Fold a partial checksum
		93	*/
		94
		95	static inline unsigned int csum_fold(unsigned int sum)
		96	{
		97	__asm__(
		98	"addl %1, %0 ;\n"
		99	"adcl $0xffff, %0 ;\n"
		100	: "=r" (sum)
		101	: "r" (sum << 16), "0" (sum & 0xffff0000)
		102	);
		103	return (~sum) >> 16;
		104	}
		105
		106	static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
		107	unsigned long daddr,
		108	unsigned short len,
		109	unsigned short proto,
		110	unsigned int sum)
		111	{
		112	__asm__(
		113	"addl %1, %0 ;\n"
		114	"adcl %2, %0 ;\n"
		115	"adcl %3, %0 ;\n"
		116	"adcl $0, %0 ;\n"
		117	: "=r" (sum)
		118	: "g" (daddr), "g"(saddr), "g"((ntohs(len)<<16)+proto*256), "0"(sum));
		119	return sum;
		120	}
		121
		122	/*
		123	* computes the checksum of the TCP/UDP pseudo-header
		124	* returns a 16-bit checksum, already complemented
		125	*/
		126	static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
		127	unsigned long daddr,
		128	unsigned short len,
		129	unsigned short proto,
		130	unsigned int sum)
		131	{
		132	return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
		133	}
		134
		135	/*
		136	* this routine is used for miscellaneous IP-like checksums, mainly
		137	* in icmp.c
		138	*/
		139
		140	static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
		141	{
		142	return csum_fold (csum_partial(buff, len, 0));
		143	}
		144
		145	#define _HAVE_ARCH_IPV6_CSUM
		146	static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
		147	struct in6_addr *daddr,
		148	__u32 len,
		149	unsigned short proto,
		150	unsigned int sum)
		151	{
		152	__asm__(
		153	"addl 0(%1), %0 ;\n"
		154	"adcl 4(%1), %0 ;\n"
		155	"adcl 8(%1), %0 ;\n"
		156	"adcl 12(%1), %0 ;\n"
		157	"adcl 0(%2), %0 ;\n"
		158	"adcl 4(%2), %0 ;\n"
		159	"adcl 8(%2), %0 ;\n"
		160	"adcl 12(%2), %0 ;\n"
		161	"adcl %3, %0 ;\n"
		162	"adcl %4, %0 ;\n"
		163	"adcl $0, %0 ;\n"
		164	: "=&r" (sum)
		165	: "r" (saddr), "r" (daddr),
		166	"r"(htonl(len)), "r"(htonl(proto)), "0"(sum));
		167
		168	return csum_fold(sum);
		169	}
		170
		171	/*
		172	* Copy and checksum to user
		173	*/
		174	#define HAVE_CSUM_COPY_USER
		175	static __inline__ unsigned int csum_and_copy_to_user(const char src, char dst,
		176	int len, int sum, int *err_ptr)
		177	{
		178	if (access_ok(VERIFY_WRITE, dst, len))
		179	return csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr);
		180
		181	if (len)
		182	*err_ptr = -EFAULT;
		183
		184	return -1; /* invalid checksum */
		185	}
		186
		187	#endif

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