[linux-2.6-block.git] / arch / ia64 / lib / checksum.c

/*
 * Network checksum routines
 *
 * Copyright (C) 1999, 2003 Hewlett-Packard Co
 *	Stephane Eranian <eranian@hpl.hp.com>
 *
 * Most of the code coming from arch/alpha/lib/checksum.c
 *
 * This file contains network checksum routines that are better done
 * in an architecture-specific manner due to speed..
 */

#include <linux/module.h>
#include <linux/string.h>

#include <asm/byteorder.h>

static inline unsigned short
from64to16 (unsigned long x)
{
	/* add up 32-bit words for 33 bits */
	x = (x & 0xffffffff) + (x >> 32);
	/* add up 16-bit and 17-bit words for 17+c bits */
	x = (x & 0xffff) + (x >> 16);
	/* add up 16-bit and 2-bit for 16+c bit */
	x = (x & 0xffff) + (x >> 16);
	/* add up carry.. */
	x = (x & 0xffff) + (x >> 16);
	return x;
}

/*
 * computes the checksum of the TCP/UDP pseudo-header
 * returns a 16-bit checksum, already complemented.
 */
unsigned short int
csum_tcpudp_magic (unsigned long saddr, unsigned long daddr, unsigned short len,
		   unsigned short proto, unsigned int sum)
{
	return ~from64to16(saddr + daddr + sum + ((unsigned long) ntohs(len) << 16) +
			   ((unsigned long) proto << 8));
}

EXPORT_SYMBOL(csum_tcpudp_magic);

unsigned int
csum_tcpudp_nofold (unsigned long saddr, unsigned long daddr, unsigned short len,
		    unsigned short proto, unsigned int sum)
{
	unsigned long result;

	result = (saddr + daddr + sum +
		  ((unsigned long) ntohs(len) << 16) +
		  ((unsigned long) proto << 8));

	/* Fold down to 32-bits so we don't lose in the typedef-less network stack.  */
	/* 64 to 33 */
	result = (result & 0xffffffff) + (result >> 32);
	/* 33 to 32 */
	result = (result & 0xffffffff) + (result >> 32);
	return result;
}

extern unsigned long do_csum (const unsigned char *, long);

/*
 * 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)
{
	unsigned long result = do_csum(buff, len);

	/* add in old sum, and carry.. */
	result += sum;
	/* 32+c bits -> 32 bits */
	result = (result & 0xffffffff) + (result >> 32);
	return result;
}

EXPORT_SYMBOL(csum_partial);

/*
 * this routine is used for miscellaneous IP-like checksums, mainly
 * in icmp.c
 */
unsigned short
ip_compute_csum (unsigned char * buff, int len)
{
	return ~do_csum(buff,len);
}

EXPORT_SYMBOL(ip_compute_csum);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* Network checksum routines
	3	*
	4	* Copyright (C) 1999, 2003 Hewlett-Packard Co
	5	* Stephane Eranian <eranian@hpl.hp.com>
	6	*
	7	* Most of the code coming from arch/alpha/lib/checksum.c
	8	*
	9	* This file contains network checksum routines that are better done
	10	* in an architecture-specific manner due to speed..
	11	*/
	12
	13	#include <linux/module.h>
	14	#include <linux/string.h>
	15
	16	#include <asm/byteorder.h>
	17
	18	static inline unsigned short
	19	from64to16 (unsigned long x)
	20	{
	21	/* add up 32-bit words for 33 bits */
	22	x = (x & 0xffffffff) + (x >> 32);
	23	/* add up 16-bit and 17-bit words for 17+c bits */
	24	x = (x & 0xffff) + (x >> 16);
	25	/* add up 16-bit and 2-bit for 16+c bit */
	26	x = (x & 0xffff) + (x >> 16);
	27	/* add up carry.. */
	28	x = (x & 0xffff) + (x >> 16);
	29	return x;
	30	}
	31
	32	/*
	33	* computes the checksum of the TCP/UDP pseudo-header
	34	* returns a 16-bit checksum, already complemented.
	35	*/
	36	unsigned short int
	37	csum_tcpudp_magic (unsigned long saddr, unsigned long daddr, unsigned short len,
	38	unsigned short proto, unsigned int sum)
	39	{
	40	return ~from64to16(saddr + daddr + sum + ((unsigned long) ntohs(len) << 16) +
	41	((unsigned long) proto << 8));
	42	}
	43
	44	EXPORT_SYMBOL(csum_tcpudp_magic);
	45
	46	unsigned int
	47	csum_tcpudp_nofold (unsigned long saddr, unsigned long daddr, unsigned short len,
	48	unsigned short proto, unsigned int sum)
	49	{
	50	unsigned long result;
	51
	52	result = (saddr + daddr + sum +
	53	((unsigned long) ntohs(len) << 16) +
	54	((unsigned long) proto << 8));
	55
	56	/* Fold down to 32-bits so we don't lose in the typedef-less network stack. */
	57	/* 64 to 33 */
	58	result = (result & 0xffffffff) + (result >> 32);
	59	/* 33 to 32 */
	60	result = (result & 0xffffffff) + (result >> 32);
	61	return result;
	62	}
	63
	64	extern unsigned long do_csum (const unsigned char *, long);
65
66	/*
67	* computes the checksum of a memory block at buff, length len,
68	* and adds in "sum" (32-bit)
69	*
70	* returns a 32-bit number suitable for feeding into itself
71	* or csum_tcpudp_magic
72	*
73	* this function must be called with even lengths, except
74	* for the last fragment, which may be odd
75	*
76	* it's best to have buff aligned on a 32-bit boundary
77	*/
78	unsigned int
79	csum_partial (const unsigned char * buff, int len, unsigned int sum)
80	{
81	unsigned long result = do_csum(buff, len);
82
83	/* add in old sum, and carry.. */
84	result += sum;
85	/* 32+c bits -> 32 bits */
86	result = (result & 0xffffffff) + (result >> 32);
87	return result;
88	}
89
90	EXPORT_SYMBOL(csum_partial);
91
92	/*
93	* this routine is used for miscellaneous IP-like checksums, mainly
94	* in icmp.c
95	*/
96	unsigned short
97	ip_compute_csum (unsigned char * buff, int len)
98	{
99	return ~do_csum(buff,len);
100	}
101
102	EXPORT_SYMBOL(ip_compute_csum);