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/*
* linux/include/asm-arm/checksum.h
*
* IP checksum routines
*
* Copyright (C) Original authors of ../asm-i386/checksum.h
* Copyright (C) 1996,1997,1998 Russell King
*/
#ifndef __ASM_ARM_CHECKSUM_H
#define __ASM_ARM_CHECKSUM_H
#ifndef __ASM_ARM_SEGMENT_H
#include <asm/segment.h>
#endif
/*
* 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);
/*
* the same as csum_partial, but copies from src while it
* checksums, and handles user-space pointer exceptions correctly, when needed.
*
* here even more important to align src and dst on a 32-bit (or even
* better 64-bit) boundary
*/
unsigned int
csum_partial_copy_nocheck(const char *src, char *dst, int len, int sum);
unsigned int
csum_partial_copy_from_user(const char *src, char *dst, int len, int sum, int *err_ptr);
#if 0
/*
* This combination is currently not used, but possible:
*/
unsigned int
csum_partial_copy_to_user(const char *src, char *dst, int len, int sum, int *err_ptr);
#endif
/*
* These are the old (and unsafe) way of doing checksums, a warning message will be
* printed if they are used and an exception occurs.
*
* these functions should go away after some time.
*/
#define csum_partial_copy_fromuser csum_partial_copy
unsigned int
csum_partial_copy(const char *src, char *dst, int len, int sum);
/*
* This is a version of ip_compute_csum() optimized for IP headers,
* which always checksum on 4 octet boundaries.
*
* Converted and optimised for ARM by R. M. King.
*
* Note: the order that the LDM registers are loaded with respect to
* the adc's doesn't matter.
*/
static inline unsigned short
ip_fast_csum(unsigned char * iph, unsigned int ihl)
{
unsigned int sum, tmp1;
__asm__ __volatile__("
sub %2, %2, #5
ldr %0, [%1], #4
ldr %3, [%1], #4
adds %0, %0, %3
ldr %3, [%1], #4
adcs %0, %0, %3
ldr %3, [%1], #4
adcs %0, %0, %3
1: ldr %3, [%1], #4
adcs %0, %0, %3
tst %2, #15
subne %2, %2, #1
bne 1b
adc %0, %0, #0
adds %0, %0, %0, lsl #16
addcs %0, %0, #0x10000
mvn %0, %0
mov %0, %0, lsr #16
"
: "=&r" (sum), "=&r" (iph), "=&r" (ihl), "=&r" (tmp1)
: "1" (iph), "2" (ihl));
return(sum);
}
/*
* Fold a partial checksum without adding pseudo headers
*/
static inline unsigned int
csum_fold(unsigned int sum)
{
__asm__("
adds %0, %0, %0, lsl #16
addcs %0, %0, #0x10000"
: "=r" (sum)
: "0" (sum));
return (~sum) >> 16;
}
static inline unsigned long
csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, unsigned short len,
unsigned short proto, unsigned int sum)
{
__asm__("
adds %0, %0, %1
adcs %0, %0, %2
adcs %0, %0, %3
adc %0, %0, #0"
: "=&r"(sum)
: "r" (daddr), "r" (saddr), "r" ((ntohs(len)<<16)+proto*256), "0" (sum));
return sum;
}
/*
* computes the checksum of the TCP/UDP pseudo-header
* returns a 16-bit checksum, already complemented
*/
static inline unsigned short int
csum_tcpudp_magic(unsigned long saddr, unsigned long daddr, unsigned short len,
unsigned short proto, unsigned int 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 unsigned short
ip_compute_csum(unsigned char * buff, int len)
{
return csum_fold(csum_partial(buff, len, 0));
}
#define _HAVE_ARCH_IPV6_CSUM
extern unsigned long
__csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr, __u32 len,
__u32 proto, unsigned int sum);
extern __inline__ unsigned short int
csum_ipv6_magic(struct in6_addr *saddr, struct in6_addr *daddr, __u16 len,
unsigned short proto, unsigned int sum)
{
return csum_fold(__csum_ipv6_magic(saddr, daddr, htonl((__u32)len),
htonl(proto), sum));
}
#endif
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