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- /*
- * 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
- 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));
- }
- static inline __wsum csum_sub(__wsum csum, __wsum addend)
- {
- return csum_add(csum, ~addend);
- }
- static inline __wsum
- csum_block_add(__wsum csum, __wsum csum2, int offset)
- {
- u32 sum = (__force u32)csum2;
- if (offset&1)
- sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF);
- return csum_add(csum, (__force __wsum)sum);
- }
- static inline __wsum
- csum_block_sub(__wsum csum, __wsum csum2, int offset)
- {
- u32 sum = (__force u32)csum2;
- if (offset&1)
- sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF);
- return csum_sub(csum, (__force __wsum)sum);
- }
- static inline __wsum csum_unfold(__sum16 n)
- {
- return (__force __wsum)n;
- }
- #define CSUM_MANGLED_0 ((__force __sum16)0xffff)
- #endif
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