add generic lib/checksum.c

#ifndef __ASM_GENERIC_CHECKSUM_H

#define __ASM_GENERIC_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

 */

extern __wsum csum_partial(const void *buff, int len, __wsum sum);

/*

 * the same as csum_partial, but copies from src while it

 * checksums

 *

 * here even more important to align src and dst on a 32-bit (or even

 * better 64-bit) boundary

 */

extern __wsum csum_partial_copy(const void *src, void *dst, int len, __wsum sum);

/*

 * the same as csum_partial_copy, but copies from user space.

 *

 * here even more important to align src and dst on a 32-bit (or even

 * better 64-bit) boundary

 */

extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,

					int len, __wsum sum, int *csum_err);

#define csum_partial_copy_nocheck(src, dst, len, sum)	\

	csum_partial_copy((src), (dst), (len), (sum))

/*

 * This is a version of ip_compute_csum() optimized for IP headers,

 * which always checksum on 4 octet boundaries.

 */

extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);

/*

 * Fold a partial checksum

 */

static inline __sum16 csum_fold(__wsum csum)

{

	u32 sum = (__force u32)csum;

	sum = (sum & 0xffff) + (sum >> 16);

	sum = (sum & 0xffff) + (sum >> 16);

	return (__force __sum16)~sum;

}

#ifndef csum_tcpudp_nofold

/*

 * computes the checksum of the TCP/UDP pseudo-header

 * returns a 16-bit checksum, already complemented

 */

extern __wsum

csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,

		unsigned short proto, __wsum sum);

#endif

static inline __sum16

csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len,

		  unsigned short proto, __wsum 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

 */

extern __sum16 ip_compute_csum(const void *buff, int len);

#endif /* __ASM_GENERIC_CHECKSUM_H */

obj-$(CONFIG_DMA_API_DEBUG) += dma-debug.o

obj-$(CONFIG_DMA_API_DEBUG) += dma-debug.o

obj-$(CONFIG_GENERIC_CSUM) += checksum.o

hostprogs-y	:= gen_crc32table

hostprogs-y	:= gen_crc32table

clean-files	:= crc32table.h

clean-files	:= crc32table.h

/*

 *

 * 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.

 *

 *		IP/TCP/UDP checksumming routines

 *

 * Authors:	Jorge Cwik, <jorge@laser.satlink.net>

 *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>

 *		Tom May, <ftom@netcom.com>

 *		Andreas Schwab, <schwab@issan.informatik.uni-dortmund.de>

 *		Lots of code moved from tcp.c and ip.c; see those files

 *		for more names.

 *

 * 03/02/96	Jes Sorensen, Andreas Schwab, Roman Hodek:

 *		Fixed some nasty bugs, causing some horrible crashes.

 *		A: At some points, the sum (%0) was used as

 *		length-counter instead of the length counter

 *		(%1). Thanks to Roman Hodek for pointing this out.

 *		B: GCC seems to mess up if one uses too many

 *		data-registers to hold input values and one tries to

 *		specify d0 and d1 as scratch registers. Letting gcc

 *		choose these registers itself solves the problem.

 *

 *		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.

 */

/* Revised by Kenneth Albanowski for m68knommu. Basic problem: unaligned access

 kills, so most of the assembly has to go. */

#include <linux/module.h>

#include <net/checksum.h>

#include <asm/byteorder.h>

static inline unsigned short from32to16(unsigned long x)

{

	/* add up 16-bit and 16-bit for 16+c bit */

	x = (x & 0xffff) + (x >> 16);

	/* add up carry.. */

	x = (x & 0xffff) + (x >> 16);

	return x;

}

static unsigned int do_csum(const unsigned char *buff, int len)

{

	int odd, count;

	unsigned long result = 0;

	if (len <= 0)

		goto out;

	odd = 1 & (unsigned long) buff;

	if (odd) {

		result = *buff;

		len--;

		buff++;

	}

	count = len >> 1;		/* nr of 16-bit words.. */

	if (count) {

		if (2 & (unsigned long) buff) {

			result += *(unsigned short *) buff;

			count--;

			len -= 2;

			buff += 2;

		}

		count >>= 1;		/* nr of 32-bit words.. */

		if (count) {

			unsigned long carry = 0;

			do {

				unsigned long w = *(unsigned long *) buff;

				count--;

				buff += 4;

				result += carry;

				result += w;

				carry = (w > result);

			} while (count);

			result += carry;

			result = (result & 0xffff) + (result >> 16);

		}

		if (len & 2) {

			result += *(unsigned short *) buff;

			buff += 2;

		}

	}

	if (len & 1)

		result += (*buff << 8);

	result = from32to16(result);

	if (odd)

		result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);

out:

	return result;

}

/*

 *	This is a version of ip_compute_csum() optimized for IP headers,

 *	which always checksum on 4 octet boundaries.

 */

__sum16 ip_fast_csum(const void *iph, unsigned int ihl)

{

	return (__force __sum16)~do_csum(iph, ihl*4);

}

EXPORT_SYMBOL(ip_fast_csum);

/*

 * 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

 */

__wsum csum_partial(const void *buff, int len, __wsum wsum)

{

	unsigned int sum = (__force unsigned int)wsum;

	unsigned int result = do_csum(buff, len);

	/* add in old sum, and carry.. */

	result += sum;

	if (sum > result)

		result += 1;

	return (__force __wsum)result;

}

EXPORT_SYMBOL(csum_partial);

/*

 * this routine is used for miscellaneous IP-like checksums, mainly

 * in icmp.c

 */

__sum16 ip_compute_csum(const void *buff, int len)

{

	return (__force __sum16)~do_csum(buff, len);

}

EXPORT_SYMBOL(ip_compute_csum);

/*

 * copy from fs while checksumming, otherwise like csum_partial

 */

__wsum

csum_partial_copy_from_user(const void __user *src, void *dst, int len,

						__wsum sum, int *csum_err)

{

	int missing;

	missing = __copy_from_user(dst, src, len);

	if (missing) {

		memset(dst + len - missing, 0, missing);

		*csum_err = -EFAULT;

	} else

		*csum_err = 0;

	return csum_partial(dst, len, sum);

}

EXPORT_SYMBOL(csum_partial_copy_from_user);

/*

 * copy from ds while checksumming, otherwise like csum_partial

 */

__wsum

csum_partial_copy(const void *src, void *dst, int len, __wsum sum)

{

	memcpy(dst, src, len);

	return csum_partial(dst, len, sum);

}

EXPORT_SYMBOL(csum_partial_copy);

#ifndef csum_tcpudp_nofold

__wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,

			unsigned short len,

			unsigned short proto,

			__wsum sum)

{

	unsigned long long s = (__force u32)sum;

	s += (__force u32)saddr;

	s += (__force u32)daddr;

#ifdef __BIG_ENDIAN

	s += proto + len;

#else

	s += (proto + len) << 8;

#endif

	s += (s >> 32);

	return (__force __wsum)s;

}

EXPORT_SYMBOL(csum_tcpudp_nofold);

#endif