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/*
* Licensed under the GPL
*/
#ifndef __UM_SYSDEP_CHECKSUM_H
#define __UM_SYSDEP_CHECKSUM_H
#include "linux/in6.h"
#include "linux/string.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
*/
unsigned int csum_partial(const unsigned char * buff, int len,
unsigned int sum);
/*
* Note: when you get a NULL pointer exception here this means someone
* passed in an incorrect kernel address to one of these functions.
*
* If you use these functions directly please don't forget the
* access_ok().
*/
static __inline__
unsigned int csum_partial_copy_nocheck(const unsigned char *src, unsigned char *dst,
int len, int sum)
{
memcpy(dst, src, len);
return csum_partial(dst, len, 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
*/
static __inline__
unsigned int csum_partial_copy_from_user(const unsigned char *src, unsigned char *dst,
int len, int sum, int *err_ptr)
{
if(copy_from_user(dst, src, len)){
*err_ptr = -EFAULT;
return(-1);
}
return csum_partial(dst, len, sum);
}
/*
* 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_from_user
/*
* This is a version of ip_compute_csum() optimized for IP headers,
* which always checksum on 4 octet boundaries.
*
* By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
* Arnt Gulbrandsen.
*/
static inline unsigned short ip_fast_csum(unsigned char * iph,
unsigned int ihl)
{
unsigned int sum;
__asm__ __volatile__(
"movl (%1), %0 ;\n"
"subl $4, %2 ;\n"
"jbe 2f ;\n"
"addl 4(%1), %0 ;\n"
"adcl 8(%1), %0 ;\n"
"adcl 12(%1), %0 ;\n"
"1: adcl 16(%1), %0 ;\n"
"lea 4(%1), %1 ;\n"
"decl %2 ;\n"
"jne 1b ;\n"
"adcl $0, %0 ;\n"
"movl %0, %2 ;\n"
"shrl $16, %0 ;\n"
"addw %w2, %w0 ;\n"
"adcl $0, %0 ;\n"
"notl %0 ;\n"
"2: ;\n"
/* Since the input registers which are loaded with iph and ipl
are modified, we must also specify them as outputs, or gcc
will assume they contain their original values. */
: "=r" (sum), "=r" (iph), "=r" (ihl)
: "1" (iph), "2" (ihl)
: "memory");
return sum;
}
/*
* Fold a partial checksum
*/
static inline unsigned int csum_fold(unsigned int sum)
{
__asm__(
"addl %1, %0 ;\n"
"adcl $0xffff, %0 ;\n"
: "=r" (sum)
: "r" (sum << 16), "0" (sum & 0xffff0000)
);
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__(
"addl %1, %0 ;\n"
"adcl %2, %0 ;\n"
"adcl %3, %0 ;\n"
"adcl $0, %0 ;\n"
: "=r" (sum)
: "g" (daddr), "g"(saddr), "g"((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
static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
struct in6_addr *daddr,
__u32 len,
unsigned short proto,
unsigned int sum)
{
__asm__(
"addl 0(%1), %0 ;\n"
"adcl 4(%1), %0 ;\n"
"adcl 8(%1), %0 ;\n"
"adcl 12(%1), %0 ;\n"
"adcl 0(%2), %0 ;\n"
"adcl 4(%2), %0 ;\n"
"adcl 8(%2), %0 ;\n"
"adcl 12(%2), %0 ;\n"
"adcl %3, %0 ;\n"
"adcl %4, %0 ;\n"
"adcl $0, %0 ;\n"
: "=&r" (sum)
: "r" (saddr), "r" (daddr),
"r"(htonl(len)), "r"(htonl(proto)), "0"(sum));
return csum_fold(sum);
}
/*
* Copy and checksum to user
*/
#define HAVE_CSUM_COPY_USER
static __inline__ unsigned int csum_and_copy_to_user(const unsigned char *src,
unsigned char *dst,
int len, int sum, int *err_ptr)
{
if (access_ok(VERIFY_WRITE, dst, len)){
if(copy_to_user(dst, src, len)){
*err_ptr = -EFAULT;
return(-1);
}
return csum_partial(src, len, sum);
}
if (len)
*err_ptr = -EFAULT;
return -1; /* invalid checksum */
}
#endif
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* Emacs will notice this stuff at the end of the file and automatically
* adjust the settings for this buffer only. This must remain at the end
* of the file.
* ---------------------------------------------------------------------------
* Local variables:
* c-file-style: "linux"
* End:
*/
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