Commit f845fced authored by Bob Copeland's avatar Bob Copeland Committed by Jan Kara
Browse files

udf: use crc_itu_t from lib instead of udf_crc 



As pointed out by Sergey Vlasov, UDF implements its own version of
the CRC ITU-T V.41.  Convert it to use the one in the library.

Signed-off-by: default avatarBob Copeland <me@bobcopeland.com>
Cc: Sergey Vlasov <vsu@altlinux.ru>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 706047a7

fs/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -663,6 +663,7 @@ config ZISOFS 


config UDF_FS

	tristate "UDF file system support"

	select CRC_ITU_T

	help

	  This is the new file system used on some CD-ROMs and DVDs. Say Y if

	  you intend to mount DVD discs or CDRW's written in packet mode, or

fs/udf/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -6,4 +6,4 @@ obj-$(CONFIG_UDF_FS) += udf.o 


udf-objs     := balloc.o dir.o file.o ialloc.o inode.o lowlevel.o namei.o \

		partition.o super.o truncate.o symlink.o fsync.o \

		crc.o directory.o misc.o udftime.o unicode.o
 
		directory.o misc.o udftime.o unicode.o

fs/udf/crc.c

deleted100644 → 0
+0 −172
Original line number Diff line number Diff line 
/*

 * crc.c

 *

 * PURPOSE

 *	Routines to generate, calculate, and test a 16-bit CRC.

 *

 * DESCRIPTION

 *	The CRC code was devised by Don P. Mitchell of AT&T Bell Laboratories

 *	and Ned W. Rhodes of Software Systems Group. It has been published in

 *	"Design and Validation of Computer Protocols", Prentice Hall,

 *	Englewood Cliffs, NJ, 1991, Chapter 3, ISBN 0-13-539925-4.

 *

 *	Copyright is held by AT&T.

 *

 *	AT&T gives permission for the free use of the CRC source code.

 *

 * COPYRIGHT

 *	This file is distributed under the terms of the GNU General Public

 *	License (GPL). Copies of the GPL can be obtained from:

 *		ftp://prep.ai.mit.edu/pub/gnu/GPL

 *	Each contributing author retains all rights to their own work.

 */



#include "udfdecl.h"



static const uint16_t crc_table[256] = {

	0x0000U, 0x1021U, 0x2042U, 0x3063U, 0x4084U, 0x50a5U, 0x60c6U, 0x70e7U,

	0x8108U, 0x9129U, 0xa14aU, 0xb16bU, 0xc18cU, 0xd1adU, 0xe1ceU, 0xf1efU,

	0x1231U, 0x0210U, 0x3273U, 0x2252U, 0x52b5U, 0x4294U, 0x72f7U, 0x62d6U,

	0x9339U, 0x8318U, 0xb37bU, 0xa35aU, 0xd3bdU, 0xc39cU, 0xf3ffU, 0xe3deU,

	0x2462U, 0x3443U, 0x0420U, 0x1401U, 0x64e6U, 0x74c7U, 0x44a4U, 0x5485U,

	0xa56aU, 0xb54bU, 0x8528U, 0x9509U, 0xe5eeU, 0xf5cfU, 0xc5acU, 0xd58dU,

	0x3653U, 0x2672U, 0x1611U, 0x0630U, 0x76d7U, 0x66f6U, 0x5695U, 0x46b4U,

	0xb75bU, 0xa77aU, 0x9719U, 0x8738U, 0xf7dfU, 0xe7feU, 0xd79dU, 0xc7bcU,

	0x48c4U, 0x58e5U, 0x6886U, 0x78a7U, 0x0840U, 0x1861U, 0x2802U, 0x3823U,

	0xc9ccU, 0xd9edU, 0xe98eU, 0xf9afU, 0x8948U, 0x9969U, 0xa90aU, 0xb92bU,

	0x5af5U, 0x4ad4U, 0x7ab7U, 0x6a96U, 0x1a71U, 0x0a50U, 0x3a33U, 0x2a12U,

	0xdbfdU, 0xcbdcU, 0xfbbfU, 0xeb9eU, 0x9b79U, 0x8b58U, 0xbb3bU, 0xab1aU,

	0x6ca6U, 0x7c87U, 0x4ce4U, 0x5cc5U, 0x2c22U, 0x3c03U, 0x0c60U, 0x1c41U,

	0xedaeU, 0xfd8fU, 0xcdecU, 0xddcdU, 0xad2aU, 0xbd0bU, 0x8d68U, 0x9d49U,

	0x7e97U, 0x6eb6U, 0x5ed5U, 0x4ef4U, 0x3e13U, 0x2e32U, 0x1e51U, 0x0e70U,

	0xff9fU, 0xefbeU, 0xdfddU, 0xcffcU, 0xbf1bU, 0xaf3aU, 0x9f59U, 0x8f78U,

	0x9188U, 0x81a9U, 0xb1caU, 0xa1ebU, 0xd10cU, 0xc12dU, 0xf14eU, 0xe16fU,

	0x1080U, 0x00a1U, 0x30c2U, 0x20e3U, 0x5004U, 0x4025U, 0x7046U, 0x6067U,

	0x83b9U, 0x9398U, 0xa3fbU, 0xb3daU, 0xc33dU, 0xd31cU, 0xe37fU, 0xf35eU,

	0x02b1U, 0x1290U, 0x22f3U, 0x32d2U, 0x4235U, 0x5214U, 0x6277U, 0x7256U,

	0xb5eaU, 0xa5cbU, 0x95a8U, 0x8589U, 0xf56eU, 0xe54fU, 0xd52cU, 0xc50dU,

	0x34e2U, 0x24c3U, 0x14a0U, 0x0481U, 0x7466U, 0x6447U, 0x5424U, 0x4405U,

	0xa7dbU, 0xb7faU, 0x8799U, 0x97b8U, 0xe75fU, 0xf77eU, 0xc71dU, 0xd73cU,

	0x26d3U, 0x36f2U, 0x0691U, 0x16b0U, 0x6657U, 0x7676U, 0x4615U, 0x5634U,

	0xd94cU, 0xc96dU, 0xf90eU, 0xe92fU, 0x99c8U, 0x89e9U, 0xb98aU, 0xa9abU,

	0x5844U, 0x4865U, 0x7806U, 0x6827U, 0x18c0U, 0x08e1U, 0x3882U, 0x28a3U,

	0xcb7dU, 0xdb5cU, 0xeb3fU, 0xfb1eU, 0x8bf9U, 0x9bd8U, 0xabbbU, 0xbb9aU,

	0x4a75U, 0x5a54U, 0x6a37U, 0x7a16U, 0x0af1U, 0x1ad0U, 0x2ab3U, 0x3a92U,

	0xfd2eU, 0xed0fU, 0xdd6cU, 0xcd4dU, 0xbdaaU, 0xad8bU, 0x9de8U, 0x8dc9U,

	0x7c26U, 0x6c07U, 0x5c64U, 0x4c45U, 0x3ca2U, 0x2c83U, 0x1ce0U, 0x0cc1U,

	0xef1fU, 0xff3eU, 0xcf5dU, 0xdf7cU, 0xaf9bU, 0xbfbaU, 0x8fd9U, 0x9ff8U,

	0x6e17U, 0x7e36U, 0x4e55U, 0x5e74U, 0x2e93U, 0x3eb2U, 0x0ed1U, 0x1ef0U

};



/*

 * udf_crc

 *

 * PURPOSE

 *	Calculate a 16-bit CRC checksum using ITU-T V.41 polynomial.

 *

 * DESCRIPTION

 *	The OSTA-UDF(tm) 1.50 standard states that using CRCs is mandatory.

 *	The polynomial used is:	x^16 + x^12 + x^15 + 1

 *

 * PRE-CONDITIONS

 *	data		Pointer to the data block.

 *	size		Size of the data block.

 *

 * POST-CONDITIONS

 *	<return>	CRC of the data block.

 *

 * HISTORY

 *	July 21, 1997 - Andrew E. Mileski

 *	Adapted from OSTA-UDF(tm) 1.50 standard.

 */

uint16_t udf_crc(const uint8_t *data, uint32_t size, uint16_t crc)

{

	while (size--)

		crc = crc_table[(crc >> 8 ^ *(data++)) & 0xffU] ^ (crc << 8);



	return crc;

}



/****************************************************************************/

#if defined(TEST)



/*

 * PURPOSE

 *	Test udf_crc()

 *

 * HISTORY

 *	July 21, 1997 - Andrew E. Mileski

 *	Adapted from OSTA-UDF(tm) 1.50 standard.

 */



unsigned char bytes[] = { 0x70U, 0x6AU, 0x77U };



int main(void)

{

	unsigned short x;



	x = udf_crc(bytes, sizeof bytes);

	printf("udf_crc: calculated = %4.4x, correct = %4.4x\n", x, 0x3299U);



	return 0;

}



#endif /* defined(TEST) */



/****************************************************************************/

#if defined(GENERATE)



/*

 * PURPOSE

 *	Generate a table for fast 16-bit CRC calculations (any polynomial).

 *

 * DESCRIPTION

 *	The ITU-T V.41 polynomial is 010041.

 *

 * HISTORY

 *	July 21, 1997 - Andrew E. Mileski

 *	Adapted from OSTA-UDF(tm) 1.50 standard.

 */



#include <stdio.h>



int main(int argc, char **argv)

{

	unsigned long crc, poly;

	int n, i;



	/* Get the polynomial */

	sscanf(argv[1], "%lo", &poly);

	if (poly & 0xffff0000U) {

		fprintf(stderr, "polynomial is too large\en");

		exit(1);

	}



	printf("/* CRC 0%o */\n", poly);



	/* Create a table */

	printf("static unsigned short crc_table[256] = {\n");

	for (n = 0; n < 256; n++) {

		if (n % 8 == 0)

			printf("\t");

		crc = n << 8;

		for (i = 0; i < 8; i++) {

			if (crc & 0x8000U)

				crc = (crc << 1) ^ poly;

			else

				crc <<= 1;

			crc &= 0xFFFFU;

		}

		if (n == 255)

			printf("0x%04xU ", crc);

		else

			printf("0x%04xU, ", crc);

		if (n % 8 == 7)

			printf("\n");

	}

	printf("};\n");



	return 0;

}



#endif /* defined(GENERATE) */

fs/udf/inode.c

+6 −5
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ 
#include <linux/buffer_head.h>

#include <linux/writeback.h>

#include <linux/slab.h>

#include <linux/crc-itu-t.h>



#include "udf_i.h"

#include "udf_sb.h"
@@ -1419,9 +1420,9 @@ static int udf_update_inode(struct inode *inode, int do_sync) 
						iinfo->i_location.

							logicalBlockNum);

		use->descTag.descCRCLength = cpu_to_le16(crclen);

		use->descTag.descCRC = cpu_to_le16(udf_crc((char *)use +

							   sizeof(tag), crclen,

							   0));

		use->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)use +

							   sizeof(tag),

							   crclen));

		use->descTag.tagChecksum = udf_tag_checksum(&use->descTag);



		mark_buffer_dirty(bh);
@@ -1584,8 +1585,8 @@ static int udf_update_inode(struct inode *inode, int do_sync) 
	crclen += iinfo->i_lenEAttr + iinfo->i_lenAlloc -

								sizeof(tag);

	fe->descTag.descCRCLength = cpu_to_le16(crclen);

	fe->descTag.descCRC = cpu_to_le16(udf_crc((char *)fe + sizeof(tag),

						  crclen, 0));

	fe->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)fe + sizeof(tag),

						  crclen));

	fe->descTag.tagChecksum = udf_tag_checksum(&fe->descTag);



	/* write the data blocks */

fs/udf/misc.c

+7 −5
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <linux/fs.h>

#include <linux/string.h>

#include <linux/buffer_head.h>

#include <linux/crc-itu-t.h>



#include "udf_i.h"

#include "udf_sb.h"
@@ -135,8 +136,8 @@ struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size, 
		/* rewrite CRC + checksum of eahd */

		crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(tag);

		eahd->descTag.descCRCLength = cpu_to_le16(crclen);

		eahd->descTag.descCRC = cpu_to_le16(udf_crc((char *)eahd +

						sizeof(tag), crclen, 0));

		eahd->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)eahd +

						sizeof(tag), crclen));

		eahd->descTag.tagChecksum = udf_tag_checksum(&eahd->descTag);

		iinfo->i_lenEAttr += size;

		return (struct genericFormat *)&ea[offset];
@@ -241,8 +242,9 @@ struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block, 


	/* Verify the descriptor CRC */

	if (le16_to_cpu(tag_p->descCRCLength) + sizeof(tag) > sb->s_blocksize ||

	    le16_to_cpu(tag_p->descCRC) == udf_crc(bh->b_data + sizeof(tag),

					le16_to_cpu(tag_p->descCRCLength), 0))

	    le16_to_cpu(tag_p->descCRC) == crc_itu_t(0,

					bh->b_data + sizeof(tag),

					le16_to_cpu(tag_p->descCRCLength)))

		return bh;



	udf_debug("Crc failure block %d: crc = %d, crclen = %d\n", block,
@@ -266,7 +268,7 @@ void udf_update_tag(char *data, int length) 
	length -= sizeof(tag);



	tptr->descCRCLength = cpu_to_le16(length);

	tptr->descCRC = cpu_to_le16(udf_crc(data + sizeof(tag), length, 0));

	tptr->descCRC = cpu_to_le16(crc_itu_t(0, data + sizeof(tag), length));

	tptr->tagChecksum = udf_tag_checksum(tptr);

}