370 строки
9.2 KiB
C
370 строки
9.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* 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.
|
|
*
|
|
* 1998/8/31 Andreas Schwab:
|
|
* Zero out rest of buffer on exception in
|
|
* csum_partial_copy_from_user.
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <net/checksum.h>
|
|
|
|
/*
|
|
* computes a partial checksum, e.g. for TCP/UDP fragments
|
|
*/
|
|
|
|
__wsum csum_partial(const void *buff, int len, __wsum sum)
|
|
{
|
|
unsigned long tmp1, tmp2;
|
|
/*
|
|
* Experiments with ethernet and slip connections show that buff
|
|
* is aligned on either a 2-byte or 4-byte boundary.
|
|
*/
|
|
__asm__("movel %2,%3\n\t"
|
|
"btst #1,%3\n\t" /* Check alignment */
|
|
"jeq 2f\n\t"
|
|
"subql #2,%1\n\t" /* buff%4==2: treat first word */
|
|
"jgt 1f\n\t"
|
|
"addql #2,%1\n\t" /* len was == 2, treat only rest */
|
|
"jra 4f\n"
|
|
"1:\t"
|
|
"addw %2@+,%0\n\t" /* add first word to sum */
|
|
"clrl %3\n\t"
|
|
"addxl %3,%0\n" /* add X bit */
|
|
"2:\t"
|
|
/* unrolled loop for the main part: do 8 longs at once */
|
|
"movel %1,%3\n\t" /* save len in tmp1 */
|
|
"lsrl #5,%1\n\t" /* len/32 */
|
|
"jeq 2f\n\t" /* not enough... */
|
|
"subql #1,%1\n"
|
|
"1:\t"
|
|
"movel %2@+,%4\n\t"
|
|
"addxl %4,%0\n\t"
|
|
"movel %2@+,%4\n\t"
|
|
"addxl %4,%0\n\t"
|
|
"movel %2@+,%4\n\t"
|
|
"addxl %4,%0\n\t"
|
|
"movel %2@+,%4\n\t"
|
|
"addxl %4,%0\n\t"
|
|
"movel %2@+,%4\n\t"
|
|
"addxl %4,%0\n\t"
|
|
"movel %2@+,%4\n\t"
|
|
"addxl %4,%0\n\t"
|
|
"movel %2@+,%4\n\t"
|
|
"addxl %4,%0\n\t"
|
|
"movel %2@+,%4\n\t"
|
|
"addxl %4,%0\n\t"
|
|
"dbra %1,1b\n\t"
|
|
"clrl %4\n\t"
|
|
"addxl %4,%0\n\t" /* add X bit */
|
|
"clrw %1\n\t"
|
|
"subql #1,%1\n\t"
|
|
"jcc 1b\n"
|
|
"2:\t"
|
|
"movel %3,%1\n\t" /* restore len from tmp1 */
|
|
"andw #0x1c,%3\n\t" /* number of rest longs */
|
|
"jeq 4f\n\t"
|
|
"lsrw #2,%3\n\t"
|
|
"subqw #1,%3\n"
|
|
"3:\t"
|
|
/* loop for rest longs */
|
|
"movel %2@+,%4\n\t"
|
|
"addxl %4,%0\n\t"
|
|
"dbra %3,3b\n\t"
|
|
"clrl %4\n\t"
|
|
"addxl %4,%0\n" /* add X bit */
|
|
"4:\t"
|
|
/* now check for rest bytes that do not fit into longs */
|
|
"andw #3,%1\n\t"
|
|
"jeq 7f\n\t"
|
|
"clrl %4\n\t" /* clear tmp2 for rest bytes */
|
|
"subqw #2,%1\n\t"
|
|
"jlt 5f\n\t"
|
|
"movew %2@+,%4\n\t" /* have rest >= 2: get word */
|
|
"swap %4\n\t" /* into bits 16..31 */
|
|
"tstw %1\n\t" /* another byte? */
|
|
"jeq 6f\n"
|
|
"5:\t"
|
|
"moveb %2@,%4\n\t" /* have odd rest: get byte */
|
|
"lslw #8,%4\n\t" /* into bits 8..15; 16..31 untouched */
|
|
"6:\t"
|
|
"addl %4,%0\n\t" /* now add rest long to sum */
|
|
"clrl %4\n\t"
|
|
"addxl %4,%0\n" /* add X bit */
|
|
"7:\t"
|
|
: "=d" (sum), "=d" (len), "=a" (buff),
|
|
"=&d" (tmp1), "=&d" (tmp2)
|
|
: "0" (sum), "1" (len), "2" (buff)
|
|
);
|
|
return(sum);
|
|
}
|
|
|
|
EXPORT_SYMBOL(csum_partial);
|
|
|
|
|
|
/*
|
|
* copy from user space while checksumming, with exception handling.
|
|
*/
|
|
|
|
__wsum
|
|
csum_and_copy_from_user(const void __user *src, void *dst, int len)
|
|
{
|
|
/*
|
|
* GCC doesn't like more than 10 operands for the asm
|
|
* statements so we have to use tmp2 for the error
|
|
* code.
|
|
*/
|
|
unsigned long tmp1, tmp2;
|
|
__wsum sum = ~0U;
|
|
|
|
__asm__("movel %2,%4\n\t"
|
|
"btst #1,%4\n\t" /* Check alignment */
|
|
"jeq 2f\n\t"
|
|
"subql #2,%1\n\t" /* buff%4==2: treat first word */
|
|
"jgt 1f\n\t"
|
|
"addql #2,%1\n\t" /* len was == 2, treat only rest */
|
|
"jra 4f\n"
|
|
"1:\n"
|
|
"10:\t"
|
|
"movesw %2@+,%4\n\t" /* add first word to sum */
|
|
"addw %4,%0\n\t"
|
|
"movew %4,%3@+\n\t"
|
|
"clrl %4\n\t"
|
|
"addxl %4,%0\n" /* add X bit */
|
|
"2:\t"
|
|
/* unrolled loop for the main part: do 8 longs at once */
|
|
"movel %1,%4\n\t" /* save len in tmp1 */
|
|
"lsrl #5,%1\n\t" /* len/32 */
|
|
"jeq 2f\n\t" /* not enough... */
|
|
"subql #1,%1\n"
|
|
"1:\n"
|
|
"11:\t"
|
|
"movesl %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"12:\t"
|
|
"movesl %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"13:\t"
|
|
"movesl %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"14:\t"
|
|
"movesl %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"15:\t"
|
|
"movesl %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"16:\t"
|
|
"movesl %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"17:\t"
|
|
"movesl %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"18:\t"
|
|
"movesl %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"dbra %1,1b\n\t"
|
|
"clrl %5\n\t"
|
|
"addxl %5,%0\n\t" /* add X bit */
|
|
"clrw %1\n\t"
|
|
"subql #1,%1\n\t"
|
|
"jcc 1b\n"
|
|
"2:\t"
|
|
"movel %4,%1\n\t" /* restore len from tmp1 */
|
|
"andw #0x1c,%4\n\t" /* number of rest longs */
|
|
"jeq 4f\n\t"
|
|
"lsrw #2,%4\n\t"
|
|
"subqw #1,%4\n"
|
|
"3:\n"
|
|
/* loop for rest longs */
|
|
"19:\t"
|
|
"movesl %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"dbra %4,3b\n\t"
|
|
"clrl %5\n\t"
|
|
"addxl %5,%0\n" /* add X bit */
|
|
"4:\t"
|
|
/* now check for rest bytes that do not fit into longs */
|
|
"andw #3,%1\n\t"
|
|
"jeq 7f\n\t"
|
|
"clrl %5\n\t" /* clear tmp2 for rest bytes */
|
|
"subqw #2,%1\n\t"
|
|
"jlt 5f\n\t"
|
|
"20:\t"
|
|
"movesw %2@+,%5\n\t" /* have rest >= 2: get word */
|
|
"movew %5,%3@+\n\t"
|
|
"swap %5\n\t" /* into bits 16..31 */
|
|
"tstw %1\n\t" /* another byte? */
|
|
"jeq 6f\n"
|
|
"5:\n"
|
|
"21:\t"
|
|
"movesb %2@,%5\n\t" /* have odd rest: get byte */
|
|
"moveb %5,%3@+\n\t"
|
|
"lslw #8,%5\n\t" /* into bits 8..15; 16..31 untouched */
|
|
"6:\t"
|
|
"addl %5,%0\n\t" /* now add rest long to sum */
|
|
"clrl %5\n\t"
|
|
"addxl %5,%0\n\t" /* add X bit */
|
|
"7:\t"
|
|
".section .fixup,\"ax\"\n"
|
|
".even\n"
|
|
/* If any exception occurs, return 0 */
|
|
"90:\t"
|
|
"clrl %0\n"
|
|
"jra 7b\n"
|
|
".previous\n"
|
|
".section __ex_table,\"a\"\n"
|
|
".long 10b,90b\n"
|
|
".long 11b,90b\n"
|
|
".long 12b,90b\n"
|
|
".long 13b,90b\n"
|
|
".long 14b,90b\n"
|
|
".long 15b,90b\n"
|
|
".long 16b,90b\n"
|
|
".long 17b,90b\n"
|
|
".long 18b,90b\n"
|
|
".long 19b,90b\n"
|
|
".long 20b,90b\n"
|
|
".long 21b,90b\n"
|
|
".previous"
|
|
: "=d" (sum), "=d" (len), "=a" (src), "=a" (dst),
|
|
"=&d" (tmp1), "=d" (tmp2)
|
|
: "0" (sum), "1" (len), "2" (src), "3" (dst)
|
|
);
|
|
|
|
return sum;
|
|
}
|
|
|
|
|
|
/*
|
|
* copy from kernel space while checksumming, otherwise like csum_partial
|
|
*/
|
|
|
|
__wsum
|
|
csum_partial_copy_nocheck(const void *src, void *dst, int len)
|
|
{
|
|
unsigned long tmp1, tmp2;
|
|
__wsum sum = 0;
|
|
__asm__("movel %2,%4\n\t"
|
|
"btst #1,%4\n\t" /* Check alignment */
|
|
"jeq 2f\n\t"
|
|
"subql #2,%1\n\t" /* buff%4==2: treat first word */
|
|
"jgt 1f\n\t"
|
|
"addql #2,%1\n\t" /* len was == 2, treat only rest */
|
|
"jra 4f\n"
|
|
"1:\t"
|
|
"movew %2@+,%4\n\t" /* add first word to sum */
|
|
"addw %4,%0\n\t"
|
|
"movew %4,%3@+\n\t"
|
|
"clrl %4\n\t"
|
|
"addxl %4,%0\n" /* add X bit */
|
|
"2:\t"
|
|
/* unrolled loop for the main part: do 8 longs at once */
|
|
"movel %1,%4\n\t" /* save len in tmp1 */
|
|
"lsrl #5,%1\n\t" /* len/32 */
|
|
"jeq 2f\n\t" /* not enough... */
|
|
"subql #1,%1\n"
|
|
"1:\t"
|
|
"movel %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"movel %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"movel %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"movel %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"movel %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"movel %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"movel %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"movel %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"dbra %1,1b\n\t"
|
|
"clrl %5\n\t"
|
|
"addxl %5,%0\n\t" /* add X bit */
|
|
"clrw %1\n\t"
|
|
"subql #1,%1\n\t"
|
|
"jcc 1b\n"
|
|
"2:\t"
|
|
"movel %4,%1\n\t" /* restore len from tmp1 */
|
|
"andw #0x1c,%4\n\t" /* number of rest longs */
|
|
"jeq 4f\n\t"
|
|
"lsrw #2,%4\n\t"
|
|
"subqw #1,%4\n"
|
|
"3:\t"
|
|
/* loop for rest longs */
|
|
"movel %2@+,%5\n\t"
|
|
"addxl %5,%0\n\t"
|
|
"movel %5,%3@+\n\t"
|
|
"dbra %4,3b\n\t"
|
|
"clrl %5\n\t"
|
|
"addxl %5,%0\n" /* add X bit */
|
|
"4:\t"
|
|
/* now check for rest bytes that do not fit into longs */
|
|
"andw #3,%1\n\t"
|
|
"jeq 7f\n\t"
|
|
"clrl %5\n\t" /* clear tmp2 for rest bytes */
|
|
"subqw #2,%1\n\t"
|
|
"jlt 5f\n\t"
|
|
"movew %2@+,%5\n\t" /* have rest >= 2: get word */
|
|
"movew %5,%3@+\n\t"
|
|
"swap %5\n\t" /* into bits 16..31 */
|
|
"tstw %1\n\t" /* another byte? */
|
|
"jeq 6f\n"
|
|
"5:\t"
|
|
"moveb %2@,%5\n\t" /* have odd rest: get byte */
|
|
"moveb %5,%3@+\n\t"
|
|
"lslw #8,%5\n" /* into bits 8..15; 16..31 untouched */
|
|
"6:\t"
|
|
"addl %5,%0\n\t" /* now add rest long to sum */
|
|
"clrl %5\n\t"
|
|
"addxl %5,%0\n" /* add X bit */
|
|
"7:\t"
|
|
: "=d" (sum), "=d" (len), "=a" (src), "=a" (dst),
|
|
"=&d" (tmp1), "=&d" (tmp2)
|
|
: "0" (sum), "1" (len), "2" (src), "3" (dst)
|
|
);
|
|
return(sum);
|
|
}
|
|
EXPORT_SYMBOL(csum_partial_copy_nocheck);
|