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/*
* BK Id: SCCS/s.checksum.h 1.8 05/17/01 18:14:24 cort
*/
#ifdef __KERNEL__
#ifndef _PPC_CHECKSUM_H
#define _PPC_CHECKSUM_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
*/
extern unsigned int csum_partial(const unsigned char * buff, int len,
unsigned int sum);
/*
* Computes the checksum of a memory block at src, length len,
* and adds in "sum" (32-bit), while copying the block to dst.
* If an access exception occurs on src or dst, it stores -EFAULT
* to *src_err or *dst_err respectively (if that pointer is not
* NULL), and, for an error on src, zeroes the rest of dst.
*
* Like csum_partial, this must be called with even lengths,
* except for the last fragment.
*/
extern unsigned int csum_partial_copy_generic(const char *src, char *dst,
int len, unsigned int sum,
int *src_err, int *dst_err);
#define csum_partial_copy_from_user(src, dst, len, sum, errp) \
csum_partial_copy_generic((src), (dst), (len), (sum), (errp), 0)
/* FIXME: this needs to be written to really do no check -- Cort */
#define csum_partial_copy_nocheck(src, dst, len, sum) \
csum_partial_copy_generic((src), (dst), (len), (sum), 0, 0)
/*
* Old versions which ignore errors.
*/
#define csum_partial_copy(src, dst, len, sum) \
csum_partial_copy_generic((src), (dst), (len), (sum), 0, 0)
#define csum_partial_copy_fromuser(src, dst, len, sum) \
csum_partial_copy_generic((src), (dst), (len), (sum), 0, 0)
/*
* turns a 32-bit partial checksum (e.g. from csum_partial) into a
* 1's complement 16-bit checksum.
*/
static inline unsigned int csum_fold(unsigned int sum)
{
unsigned int tmp;
/* swap the two 16-bit halves of sum */
__asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
/* if there is a carry from adding the two 16-bit halves,
it will carry from the lower half into the upper half,
giving us the correct sum in the upper half. */
sum = ~(sum + tmp) >> 16;
return sum;
}
/*
* this routine is used for miscellaneous IP-like checksums, mainly
* in icmp.c
*/
static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
{
return csum_fold(csum_partial(buff, len, 0));
}
/*
* FIXME: I swiped this one from the sparc and made minor modifications.
* It may not be correct. -- Cort
*/
static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
unsigned long daddr,
unsigned short len,
unsigned short proto,
unsigned int sum)
{
__asm__("\n\
addc %0,%0,%1 \n\
adde %0,%0,%2 \n\
adde %0,%0,%3 \n\
addze %0,%0 \n\
"
: "=r" (sum)
: "r" (daddr), "r"(saddr), "r"((proto<<16)+len), "0"(sum));
return sum;
}
/*
* This is a version of ip_compute_csum() optimized for IP headers,
* which always checksum on 4 octet boundaries. ihl is the number
* of 32-bit words and is always >= 5.
*/
extern unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl);
/*
* computes the checksum of the TCP/UDP pseudo-header
* returns a 16-bit checksum, already complemented
*/
extern unsigned short csum_tcpudp_magic(unsigned long saddr,
unsigned long daddr,
unsigned short len,
unsigned short proto,
unsigned int sum);
#endif
#endif /* __KERNEL__ */
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