88 lines
2.2 KiB
C
88 lines
2.2 KiB
C
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/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* Checksumming functions for IP, TCP, UDP and so on
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*
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* Authors: Jorge Cwik, <jorge@laser.satlink.net>
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* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
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* Borrows very liberally from tcp.c and ip.c, see those
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* files for more names.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef _CHECKSUM_H
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#define _CHECKSUM_H
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#include <linux/errno.h>
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#include <asm/types.h>
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#include <asm/byteorder.h>
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#include <asm/uaccess.h>
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#include <asm/checksum.h>
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#ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
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static inline
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unsigned int csum_and_copy_from_user (const unsigned char __user *src, unsigned char *dst,
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int len, int sum, int *err_ptr)
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{
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if (access_ok(VERIFY_READ, src, len))
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return csum_partial_copy_from_user(src, dst, len, sum, err_ptr);
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if (len)
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*err_ptr = -EFAULT;
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return sum;
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}
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#endif
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#ifndef HAVE_CSUM_COPY_USER
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static __inline__ unsigned int csum_and_copy_to_user
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(const unsigned char *src, unsigned char __user *dst, int len, unsigned int sum, int *err_ptr)
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{
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sum = csum_partial(src, len, sum);
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if (access_ok(VERIFY_WRITE, dst, len)) {
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if (copy_to_user(dst, src, len) == 0)
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return sum;
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}
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if (len)
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*err_ptr = -EFAULT;
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return -1; /* invalid checksum */
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}
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#endif
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static inline unsigned int csum_add(unsigned int csum, unsigned int addend)
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{
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csum += addend;
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return csum + (csum < addend);
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}
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static inline unsigned int csum_sub(unsigned int csum, unsigned int addend)
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{
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return csum_add(csum, ~addend);
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}
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static inline unsigned int
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csum_block_add(unsigned int csum, unsigned int csum2, int offset)
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{
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if (offset&1)
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csum2 = ((csum2&0xFF00FF)<<8)+((csum2>>8)&0xFF00FF);
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return csum_add(csum, csum2);
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}
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static inline unsigned int
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csum_block_sub(unsigned int csum, unsigned int csum2, int offset)
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{
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if (offset&1)
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csum2 = ((csum2&0xFF00FF)<<8)+((csum2>>8)&0xFF00FF);
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return csum_sub(csum, csum2);
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}
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#endif
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