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108 lines
3.1 KiB
108 lines
3.1 KiB
20 years ago
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#ifdef __KERNEL__
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#ifndef _PPC_CHECKSUM_H
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#define _PPC_CHECKSUM_H
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/*
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* computes the checksum of a memory block at buff, length len,
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* and adds in "sum" (32-bit)
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*
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* returns a 32-bit number suitable for feeding into itself
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* or csum_tcpudp_magic
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*
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* this function must be called with even lengths, except
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* for the last fragment, which may be odd
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*
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* it's best to have buff aligned on a 32-bit boundary
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*/
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extern unsigned int csum_partial(const unsigned char * buff, int len,
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unsigned int sum);
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/*
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* Computes the checksum of a memory block at src, length len,
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* and adds in "sum" (32-bit), while copying the block to dst.
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* If an access exception occurs on src or dst, it stores -EFAULT
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* to *src_err or *dst_err respectively (if that pointer is not
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* NULL), and, for an error on src, zeroes the rest of dst.
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*
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* Like csum_partial, this must be called with even lengths,
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* except for the last fragment.
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*/
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extern unsigned int csum_partial_copy_generic(const char *src, char *dst,
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int len, unsigned int sum,
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int *src_err, int *dst_err);
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#define csum_partial_copy_from_user(src, dst, len, sum, errp) \
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csum_partial_copy_generic((__force void *)(src), (dst), (len), (sum), (errp), NULL)
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/* FIXME: this needs to be written to really do no check -- Cort */
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#define csum_partial_copy_nocheck(src, dst, len, sum) \
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csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL)
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/*
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* turns a 32-bit partial checksum (e.g. from csum_partial) into a
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* 1's complement 16-bit checksum.
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*/
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static inline unsigned int csum_fold(unsigned int sum)
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{
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unsigned int tmp;
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/* swap the two 16-bit halves of sum */
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__asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum));
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/* if there is a carry from adding the two 16-bit halves,
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it will carry from the lower half into the upper half,
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giving us the correct sum in the upper half. */
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sum = ~(sum + tmp) >> 16;
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return sum;
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}
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/*
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* this routine is used for miscellaneous IP-like checksums, mainly
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* in icmp.c
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*/
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static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
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{
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return csum_fold(csum_partial(buff, len, 0));
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}
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/*
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* FIXME: I swiped this one from the sparc and made minor modifications.
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* It may not be correct. -- Cort
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*/
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static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
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unsigned long daddr,
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unsigned short len,
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unsigned short proto,
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unsigned int sum)
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{
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__asm__("\n\
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addc %0,%0,%1 \n\
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adde %0,%0,%2 \n\
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adde %0,%0,%3 \n\
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addze %0,%0 \n\
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"
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: "=r" (sum)
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: "r" (daddr), "r"(saddr), "r"((proto<<16)+len), "0"(sum));
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return sum;
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}
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/*
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* This is a version of ip_compute_csum() optimized for IP headers,
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* which always checksum on 4 octet boundaries. ihl is the number
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* of 32-bit words and is always >= 5.
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*/
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extern unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl);
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/*
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* computes the checksum of the TCP/UDP pseudo-header
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* returns a 16-bit checksum, already complemented
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*/
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extern unsigned short csum_tcpudp_magic(unsigned long saddr,
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unsigned long daddr,
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unsigned short len,
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unsigned short proto,
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unsigned int sum);
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#endif
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#endif /* __KERNEL__ */
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