mirror of
https://github.com/torvalds/linux
synced 2024-11-05 18:23:50 +00:00
1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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.
|
|
*/
|
|
unsigned short int
|
|
csum_tcpudp_magic (unsigned long saddr, unsigned long daddr, unsigned short len,
|
|
unsigned short proto, unsigned int sum)
|
|
{
|
|
return ~from64to16(saddr + daddr + sum + ((unsigned long) ntohs(len) << 16) +
|
|
((unsigned long) proto << 8));
|
|
}
|
|
|
|
EXPORT_SYMBOL(csum_tcpudp_magic);
|
|
|
|
unsigned int
|
|
csum_tcpudp_nofold (unsigned long saddr, unsigned long daddr, unsigned short len,
|
|
unsigned short proto, unsigned int sum)
|
|
{
|
|
unsigned long result;
|
|
|
|
result = (saddr + daddr + sum +
|
|
((unsigned long) ntohs(len) << 16) +
|
|
((unsigned long) 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 result;
|
|
}
|
|
|
|
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
|
|
*/
|
|
unsigned int
|
|
csum_partial (const unsigned char * buff, int len, unsigned int sum)
|
|
{
|
|
unsigned long result = do_csum(buff, len);
|
|
|
|
/* add in old sum, and carry.. */
|
|
result += sum;
|
|
/* 32+c bits -> 32 bits */
|
|
result = (result & 0xffffffff) + (result >> 32);
|
|
return result;
|
|
}
|
|
|
|
EXPORT_SYMBOL(csum_partial);
|
|
|
|
/*
|
|
* this routine is used for miscellaneous IP-like checksums, mainly
|
|
* in icmp.c
|
|
*/
|
|
unsigned short
|
|
ip_compute_csum (unsigned char * buff, int len)
|
|
{
|
|
return ~do_csum(buff,len);
|
|
}
|
|
|
|
EXPORT_SYMBOL(ip_compute_csum);
|