148 строки
3.4 KiB
C
148 строки
3.4 KiB
C
/*
|
|
* S390 fast network checksum routines
|
|
*
|
|
* S390 version
|
|
* Copyright IBM Corp. 1999
|
|
* Author(s): Ulrich Hild (first version)
|
|
* Martin Schwidefsky (heavily optimized CKSM version)
|
|
* D.J. Barrow (third attempt)
|
|
*/
|
|
|
|
#ifndef _S390_CHECKSUM_H
|
|
#define _S390_CHECKSUM_H
|
|
|
|
#include <asm/uaccess.h>
|
|
|
|
/*
|
|
* 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
|
|
*/
|
|
static inline __wsum
|
|
csum_partial(const void *buff, int len, __wsum sum)
|
|
{
|
|
register unsigned long reg2 asm("2") = (unsigned long) buff;
|
|
register unsigned long reg3 asm("3") = (unsigned long) len;
|
|
|
|
asm volatile(
|
|
"0: cksm %0,%1\n" /* do checksum on longs */
|
|
" jo 0b\n"
|
|
: "+d" (sum), "+d" (reg2), "+d" (reg3) : : "cc", "memory");
|
|
return sum;
|
|
}
|
|
|
|
/*
|
|
* the same as csum_partial_copy, but copies from user space.
|
|
*
|
|
* here even more important to align src and dst on a 32-bit (or even
|
|
* better 64-bit) boundary
|
|
*
|
|
* Copy from userspace and compute checksum. If we catch an exception
|
|
* then zero the rest of the buffer.
|
|
*/
|
|
static inline __wsum
|
|
csum_partial_copy_from_user(const void __user *src, void *dst,
|
|
int len, __wsum sum,
|
|
int *err_ptr)
|
|
{
|
|
int missing;
|
|
|
|
missing = copy_from_user(dst, src, len);
|
|
if (missing) {
|
|
memset(dst + len - missing, 0, missing);
|
|
*err_ptr = -EFAULT;
|
|
}
|
|
|
|
return csum_partial(dst, len, sum);
|
|
}
|
|
|
|
|
|
static inline __wsum
|
|
csum_partial_copy_nocheck (const void *src, void *dst, int len, __wsum sum)
|
|
{
|
|
memcpy(dst,src,len);
|
|
return csum_partial(dst, len, sum);
|
|
}
|
|
|
|
/*
|
|
* Fold a partial checksum without adding pseudo headers
|
|
*/
|
|
static inline __sum16 csum_fold(__wsum sum)
|
|
{
|
|
u32 csum = (__force u32) sum;
|
|
|
|
csum += (csum >> 16) + (csum << 16);
|
|
csum >>= 16;
|
|
return (__force __sum16) ~csum;
|
|
}
|
|
|
|
/*
|
|
* This is a version of ip_compute_csum() optimized for IP headers,
|
|
* which always checksum on 4 octet boundaries.
|
|
*
|
|
*/
|
|
static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
|
|
{
|
|
return csum_fold(csum_partial(iph, ihl*4, 0));
|
|
}
|
|
|
|
/*
|
|
* computes the checksum of the TCP/UDP pseudo-header
|
|
* returns a 32-bit checksum
|
|
*/
|
|
static inline __wsum
|
|
csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
|
|
unsigned short len, unsigned short proto,
|
|
__wsum sum)
|
|
{
|
|
__u32 csum = (__force __u32)sum;
|
|
|
|
csum += (__force __u32)saddr;
|
|
if (csum < (__force __u32)saddr)
|
|
csum++;
|
|
|
|
csum += (__force __u32)daddr;
|
|
if (csum < (__force __u32)daddr)
|
|
csum++;
|
|
|
|
csum += len + proto;
|
|
if (csum < len + proto)
|
|
csum++;
|
|
|
|
return (__force __wsum)csum;
|
|
}
|
|
|
|
/*
|
|
* computes the checksum of the TCP/UDP pseudo-header
|
|
* returns a 16-bit checksum, already complemented
|
|
*/
|
|
|
|
static inline __sum16
|
|
csum_tcpudp_magic(__be32 saddr, __be32 daddr,
|
|
unsigned short len, unsigned short proto,
|
|
__wsum sum)
|
|
{
|
|
return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
|
|
}
|
|
|
|
/*
|
|
* this routine is used for miscellaneous IP-like checksums, mainly
|
|
* in icmp.c
|
|
*/
|
|
|
|
static inline __sum16 ip_compute_csum(const void *buff, int len)
|
|
{
|
|
return csum_fold(csum_partial(buff, len, 0));
|
|
}
|
|
|
|
#endif /* _S390_CHECKSUM_H */
|
|
|
|
|