mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-16 08:44:21 +08:00
547c178b72
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
102 lines
2.5 KiB
C
102 lines
2.5 KiB
C
/*
|
|
* Network checksum routines
|
|
*
|
|
* Copyright (C) 1999, 2003 Hewlett-Packard Co
|
|
* Stephane Eranian <eranian@hpl.hp.com>
|
|
*
|
|
* Most of the code coming from arch/alpha/lib/checksum.c
|
|
*
|
|
* This file contains network checksum routines that are better done
|
|
* in an architecture-specific manner due to speed..
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/string.h>
|
|
|
|
#include <asm/byteorder.h>
|
|
|
|
static inline unsigned short
|
|
from64to16 (unsigned long x)
|
|
{
|
|
/* add up 32-bit words for 33 bits */
|
|
x = (x & 0xffffffff) + (x >> 32);
|
|
/* add up 16-bit and 17-bit words for 17+c bits */
|
|
x = (x & 0xffff) + (x >> 16);
|
|
/* add up 16-bit and 2-bit for 16+c bit */
|
|
x = (x & 0xffff) + (x >> 16);
|
|
/* add up carry.. */
|
|
x = (x & 0xffff) + (x >> 16);
|
|
return x;
|
|
}
|
|
|
|
/*
|
|
* computes the checksum of the TCP/UDP pseudo-header
|
|
* returns a 16-bit checksum, already complemented.
|
|
*/
|
|
__sum16
|
|
csum_tcpudp_magic (__be32 saddr, __be32 daddr, unsigned short len,
|
|
unsigned short proto, __wsum sum)
|
|
{
|
|
return (__force __sum16)~from64to16(
|
|
(__force u64)saddr + (__force u64)daddr +
|
|
(__force u64)sum + ((len + proto) << 8));
|
|
}
|
|
|
|
EXPORT_SYMBOL(csum_tcpudp_magic);
|
|
|
|
__wsum
|
|
csum_tcpudp_nofold (__be32 saddr, __be32 daddr, unsigned short len,
|
|
unsigned short proto, __wsum sum)
|
|
{
|
|
unsigned long result;
|
|
|
|
result = (__force u64)saddr + (__force u64)daddr +
|
|
(__force u64)sum + ((len + proto) << 8);
|
|
|
|
/* Fold down to 32-bits so we don't lose in the typedef-less network stack. */
|
|
/* 64 to 33 */
|
|
result = (result & 0xffffffff) + (result >> 32);
|
|
/* 33 to 32 */
|
|
result = (result & 0xffffffff) + (result >> 32);
|
|
return (__force __wsum)result;
|
|
}
|
|
EXPORT_SYMBOL(csum_tcpudp_nofold);
|
|
|
|
extern unsigned long do_csum (const unsigned char *, long);
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
u64 result = do_csum(buff, len);
|
|
|
|
/* add in old sum, and carry.. */
|
|
result += (__force u32)sum;
|
|
/* 32+c bits -> 32 bits */
|
|
result = (result & 0xffffffff) + (result >> 32);
|
|
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);
|