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154 lines
3.9 KiB
154 lines
3.9 KiB
/* |
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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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__wsum csum_and_copy_from_user (const void __user *src, void *dst, |
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int len, __wsum 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__ __wsum csum_and_copy_to_user |
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(const void *src, void __user *dst, int len, __wsum 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 (__force __wsum)-1; /* invalid checksum */ |
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} |
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#endif |
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#ifndef HAVE_ARCH_CSUM_ADD |
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static inline __wsum csum_add(__wsum csum, __wsum addend) |
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{ |
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u32 res = (__force u32)csum; |
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res += (__force u32)addend; |
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return (__force __wsum)(res + (res < (__force u32)addend)); |
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} |
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#endif |
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static inline __wsum csum_sub(__wsum csum, __wsum addend) |
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{ |
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return csum_add(csum, ~addend); |
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} |
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static inline __sum16 csum16_add(__sum16 csum, __be16 addend) |
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{ |
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u16 res = (__force u16)csum; |
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res += (__force u16)addend; |
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return (__force __sum16)(res + (res < (__force u16)addend)); |
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} |
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static inline __sum16 csum16_sub(__sum16 csum, __be16 addend) |
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{ |
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return csum16_add(csum, ~addend); |
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} |
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static inline __wsum |
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csum_block_add(__wsum csum, __wsum csum2, int offset) |
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{ |
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u32 sum = (__force u32)csum2; |
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if (offset&1) |
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sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF); |
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return csum_add(csum, (__force __wsum)sum); |
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} |
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static inline __wsum |
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csum_block_add_ext(__wsum csum, __wsum csum2, int offset, int len) |
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{ |
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return csum_block_add(csum, csum2, offset); |
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} |
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static inline __wsum |
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csum_block_sub(__wsum csum, __wsum csum2, int offset) |
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{ |
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u32 sum = (__force u32)csum2; |
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if (offset&1) |
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sum = ((sum&0xFF00FF)<<8)+((sum>>8)&0xFF00FF); |
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return csum_sub(csum, (__force __wsum)sum); |
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} |
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static inline __wsum csum_unfold(__sum16 n) |
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{ |
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return (__force __wsum)n; |
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} |
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static inline __wsum csum_partial_ext(const void *buff, int len, __wsum sum) |
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{ |
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return csum_partial(buff, len, sum); |
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} |
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#define CSUM_MANGLED_0 ((__force __sum16)0xffff) |
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static inline void csum_replace4(__sum16 *sum, __be32 from, __be32 to) |
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{ |
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*sum = csum_fold(csum_add(csum_sub(~csum_unfold(*sum), from), to)); |
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} |
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/* Implements RFC 1624 (Incremental Internet Checksum) |
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* 3. Discussion states : |
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* HC' = ~(~HC + ~m + m') |
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* m : old value of a 16bit field |
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* m' : new value of a 16bit field |
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*/ |
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static inline void csum_replace2(__sum16 *sum, __be16 old, __be16 new) |
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{ |
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*sum = ~csum16_add(csum16_sub(~(*sum), old), new); |
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} |
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struct sk_buff; |
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void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb, |
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__be32 from, __be32 to, int pseudohdr); |
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void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb, |
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const __be32 *from, const __be32 *to, |
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int pseudohdr); |
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static inline void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb, |
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__be16 from, __be16 to, |
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int pseudohdr) |
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{ |
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inet_proto_csum_replace4(sum, skb, (__force __be32)from, |
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(__force __be32)to, pseudohdr); |
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} |
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#endif
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