140 lines
3.5 KiB
C
140 lines
3.5 KiB
C
/*
|
|
* File: arch/blackfin/lib/checksum.c
|
|
* Based on: none - original work
|
|
* Author:
|
|
*
|
|
* Created:
|
|
* Description: 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.
|
|
*
|
|
* Modified:
|
|
* Copyright 2004-2006 Analog Devices Inc.
|
|
*
|
|
* Bugs: Enter bugs at http://blackfin.uclinux.org/
|
|
*
|
|
* 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.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, see the file COPYING, or write
|
|
* to the Free Software Foundation, Inc.,
|
|
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#include <net/checksum.h>
|
|
#include <asm/checksum.h>
|
|
|
|
#ifdef CONFIG_IP_CHECKSUM_L1
|
|
static unsigned short do_csum(const unsigned char *buff, int len)__attribute__((l1_text));
|
|
#endif
|
|
|
|
static unsigned short do_csum(const unsigned char *buff, int len)
|
|
{
|
|
register unsigned long sum = 0;
|
|
int swappem = 0;
|
|
|
|
if (1 & (unsigned long)buff) {
|
|
sum = *buff << 8;
|
|
buff++;
|
|
len--;
|
|
++swappem;
|
|
}
|
|
|
|
while (len > 1) {
|
|
sum += *(unsigned short *)buff;
|
|
buff += 2;
|
|
len -= 2;
|
|
}
|
|
|
|
if (len > 0)
|
|
sum += *buff;
|
|
|
|
/* Fold 32-bit sum to 16 bits */
|
|
while (sum >> 16)
|
|
sum = (sum & 0xffff) + (sum >> 16);
|
|
|
|
if (swappem)
|
|
sum = ((sum & 0xff00) >> 8) + ((sum & 0x00ff) << 8);
|
|
|
|
return sum;
|
|
|
|
}
|
|
|
|
/*
|
|
* This is a version of ip_compute_csum() optimized for IP headers,
|
|
* which always checksum on 4 octet boundaries.
|
|
*/
|
|
__sum16 ip_fast_csum(unsigned char *iph, unsigned int ihl)
|
|
{
|
|
return (__force __sum16)~do_csum(iph, ihl * 4);
|
|
}
|
|
|
|
/*
|
|
* 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 sum)
|
|
{
|
|
/*
|
|
* Just in case we get nasty checksum data...
|
|
* Like 0xffff6ec3 in the case of our IPv6 multicast header.
|
|
* We fold to begin with, as well as at the end.
|
|
*/
|
|
sum = (sum & 0xffff) + (sum >> 16);
|
|
|
|
sum += do_csum(buff, len);
|
|
|
|
sum = (sum & 0xffff) + (sum >> 16);
|
|
|
|
return sum;
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
if (csum_err)
|
|
*csum_err = 0;
|
|
memcpy(dst, (__force void *)src, len);
|
|
return csum_partial(dst, len, sum);
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
}
|