86 lines
2.4 KiB
C
86 lines
2.4 KiB
C
|
/* $Id: old_checksum.c,v 1.3 2003/10/27 08:04:32 starvik Exp $
|
||
|
|
*
|
||
|
|
* 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>
|
||
|
|
* Lots of code moved from tcp.c and ip.c; see those files
|
||
|
|
* for more names.
|
||
|
|
*
|
||
|
|
* 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.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <net/checksum.h>
|
||
|
|
#include <net/module.h>
|
||
|
|
|
||
|
|
#undef PROFILE_CHECKSUM
|
||
|
|
|
||
|
|
#ifdef PROFILE_CHECKSUM
|
||
|
|
/* these are just for profiling the checksum code with an oscillioscope.. uh */
|
||
|
|
#if 0
|
||
|
|
#define BITOFF *((unsigned char *)0xb0000030) = 0xff
|
||
|
|
#define BITON *((unsigned char *)0xb0000030) = 0x0
|
||
|
|
#endif
|
||
|
|
#include <asm/io.h>
|
||
|
|
#define CBITON LED_ACTIVE_SET(1)
|
||
|
|
#define CBITOFF LED_ACTIVE_SET(0)
|
||
|
|
#define BITOFF
|
||
|
|
#define BITON
|
||
|
|
#else
|
||
|
|
#define BITOFF
|
||
|
|
#define BITON
|
||
|
|
#define CBITOFF
|
||
|
|
#define CBITON
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/*
|
||
|
|
* computes a partial checksum, e.g. for TCP/UDP fragments
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <asm/delay.h>
|
||
|
|
|
||
|
|
unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum)
|
||
|
|
{
|
||
|
|
/*
|
||
|
|
* Experiments with ethernet and slip connections show that buff
|
||
|
|
* is aligned on either a 2-byte or 4-byte boundary.
|
||
|
|
*/
|
||
|
|
const unsigned char *endMarker = buff + len;
|
||
|
|
const unsigned char *marker = endMarker - (len % 16);
|
||
|
|
#if 0
|
||
|
|
if((int)buff & 0x3)
|
||
|
|
printk("unaligned buff %p\n", buff);
|
||
|
|
__delay(900); /* extra delay of 90 us to test performance hit */
|
||
|
|
#endif
|
||
|
|
BITON;
|
||
|
|
while (buff < marker) {
|
||
|
|
sum += *((unsigned short *)buff)++;
|
||
|
|
sum += *((unsigned short *)buff)++;
|
||
|
|
sum += *((unsigned short *)buff)++;
|
||
|
|
sum += *((unsigned short *)buff)++;
|
||
|
|
sum += *((unsigned short *)buff)++;
|
||
|
|
sum += *((unsigned short *)buff)++;
|
||
|
|
sum += *((unsigned short *)buff)++;
|
||
|
|
sum += *((unsigned short *)buff)++;
|
||
|
|
}
|
||
|
|
marker = endMarker - (len % 2);
|
||
|
|
while(buff < marker) {
|
||
|
|
sum += *((unsigned short *)buff)++;
|
||
|
|
}
|
||
|
|
if(endMarker - buff > 0) {
|
||
|
|
sum += *buff; /* add extra byte seperately */
|
||
|
|
}
|
||
|
|
BITOFF;
|
||
|
|
return(sum);
|
||
|
|
}
|
||
|
|
|
||
|
|
EXPORT_SYMBOL(csum_partial);
|