forked from rrcarlosr/Jetpack
186 lines
4.6 KiB
C
186 lines
4.6 KiB
C
/*
|
|
* INET An implementation of the TCP/IP protocol suite for the LINUX
|
|
* operating system. INET is implemented using the BSD Socket
|
|
* interface as the means of communication with the user level.
|
|
*
|
|
* Checksumming functions for IP, TCP, UDP and so on
|
|
*
|
|
* Authors: Jorge Cwik, <jorge@laser.satlink.net>
|
|
* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
|
|
* Borrows very liberally from tcp.c and ip.c, see those
|
|
* files for more names.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the License, or (at your option) any later version.
|
|
*/
|
|
|
|
#ifndef _CHECKSUM_H
|
|
#define _CHECKSUM_H
|
|
|
|
#include <linux/errno.h>
|
|
#include <asm/types.h>
|
|
#include <asm/byteorder.h>
|
|
#include <asm/uaccess.h>
|
|
#include <asm/checksum.h>
|
|
|
|
#ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
|
|
static inline
|
|
__wsum csum_and_copy_from_user (const void __user *src, void *dst,
|
|
int len, __wsum sum, int *err_ptr)
|
|
{
|
|
if (access_ok(VERIFY_READ, src, len))
|
|
return csum_partial_copy_from_user(src, dst, len, sum, err_ptr);
|
|
|
|
if (len)
|
|
*err_ptr = -EFAULT;
|
|
|
|
return sum;
|
|
}
|
|
#endif
|
|
|
|
#ifndef HAVE_CSUM_COPY_USER
|
|
static __inline__ __wsum csum_and_copy_to_user
|
|
(const void *src, void __user *dst, int len, __wsum sum, int *err_ptr)
|
|
{
|
|
sum = csum_partial(src, len, sum);
|
|
|
|
if (access_ok(VERIFY_WRITE, dst, len)) {
|
|
if (copy_to_user(dst, src, len) == 0)
|
|
return sum;
|
|
}
|
|
if (len)
|
|
*err_ptr = -EFAULT;
|
|
|
|
return (__force __wsum)-1; /* invalid checksum */
|
|
}
|
|
#endif
|
|
|
|
#ifndef HAVE_ARCH_CSUM_ADD
|
|
static inline __wsum csum_add(__wsum csum, __wsum addend)
|
|
{
|
|
u32 res = (__force u32)csum;
|
|
res += (__force u32)addend;
|
|
return (__force __wsum)(res + (res < (__force u32)addend));
|
|
}
|
|
#endif
|
|
|
|
static inline __wsum csum_sub(__wsum csum, __wsum addend)
|
|
{
|
|
return csum_add(csum, ~addend);
|
|
}
|
|
|
|
static inline __sum16 csum16_add(__sum16 csum, __be16 addend)
|
|
{
|
|
u16 res = (__force u16)csum;
|
|
|
|
res += (__force u16)addend;
|
|
return (__force __sum16)(res + (res < (__force u16)addend));
|
|
}
|
|
|
|
static inline __sum16 csum16_sub(__sum16 csum, __be16 addend)
|
|
{
|
|
return csum16_add(csum, ~addend);
|
|
}
|
|
|
|
static inline __wsum
|
|
csum_block_add(__wsum csum, __wsum csum2, int offset)
|
|
{
|
|
u32 sum = (__force u32)csum2;
|
|
|
|
/* rotate sum to align it with a 16b boundary */
|
|
if (offset & 1)
|
|
sum = ror32(sum, 8);
|
|
|
|
return csum_add(csum, (__force __wsum)sum);
|
|
}
|
|
|
|
static inline __wsum
|
|
csum_block_add_ext(__wsum csum, __wsum csum2, int offset, int len)
|
|
{
|
|
return csum_block_add(csum, csum2, offset);
|
|
}
|
|
|
|
static inline __wsum
|
|
csum_block_sub(__wsum csum, __wsum csum2, int offset)
|
|
{
|
|
return csum_block_add(csum, ~csum2, offset);
|
|
}
|
|
|
|
static inline __wsum csum_unfold(__sum16 n)
|
|
{
|
|
return (__force __wsum)n;
|
|
}
|
|
|
|
static inline __wsum csum_partial_ext(const void *buff, int len, __wsum sum)
|
|
{
|
|
return csum_partial(buff, len, sum);
|
|
}
|
|
|
|
#define CSUM_MANGLED_0 ((__force __sum16)0xffff)
|
|
|
|
static inline void csum_replace_by_diff(__sum16 *sum, __wsum diff)
|
|
{
|
|
*sum = csum_fold(csum_add(diff, ~csum_unfold(*sum)));
|
|
}
|
|
|
|
static inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to)
|
|
{
|
|
__wsum tmp = csum_sub(~csum_unfold(*sum), (__force __wsum)from);
|
|
|
|
*sum = csum_fold(csum_add(tmp, (__force __wsum)to));
|
|
}
|
|
|
|
/* Implements RFC 1624 (Incremental Internet Checksum)
|
|
* 3. Discussion states :
|
|
* HC' = ~(~HC + ~m + m')
|
|
* m : old value of a 16bit field
|
|
* m' : new value of a 16bit field
|
|
*/
|
|
static inline void csum_replace2(__sum16 *sum, __be16 old, __be16 new)
|
|
{
|
|
*sum = ~csum16_add(csum16_sub(~(*sum), old), new);
|
|
}
|
|
|
|
struct sk_buff;
|
|
void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
|
|
__be32 from, __be32 to, bool pseudohdr);
|
|
void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
|
|
const __be32 *from, const __be32 *to,
|
|
bool pseudohdr);
|
|
void inet_proto_csum_replace_by_diff(__sum16 *sum, struct sk_buff *skb,
|
|
__wsum diff, bool pseudohdr);
|
|
|
|
static inline void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb,
|
|
__be16 from, __be16 to,
|
|
bool pseudohdr)
|
|
{
|
|
inet_proto_csum_replace4(sum, skb, (__force __be32)from,
|
|
(__force __be32)to, pseudohdr);
|
|
}
|
|
|
|
static inline __wsum remcsum_adjust(void *ptr, __wsum csum,
|
|
int start, int offset)
|
|
{
|
|
__sum16 *psum = (__sum16 *)(ptr + offset);
|
|
__wsum delta;
|
|
|
|
/* Subtract out checksum up to start */
|
|
csum = csum_sub(csum, csum_partial(ptr, start, 0));
|
|
|
|
/* Set derived checksum in packet */
|
|
delta = csum_sub((__force __wsum)csum_fold(csum),
|
|
(__force __wsum)*psum);
|
|
*psum = csum_fold(csum);
|
|
|
|
return delta;
|
|
}
|
|
|
|
static inline void remcsum_unadjust(__sum16 *psum, __wsum delta)
|
|
{
|
|
*psum = csum_fold(csum_sub(delta, *psum));
|
|
}
|
|
|
|
#endif
|