66 lines
1.6 KiB
C
66 lines
1.6 KiB
C
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/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ASM_GENERIC_CHECKSUM_H
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#define __ASM_GENERIC_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 __wsum csum_partial(const void *buff, int len, __wsum sum);
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#ifndef ip_fast_csum
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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.
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*/
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extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
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#endif
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#ifndef csum_fold
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/*
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* Fold a partial checksum
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*/
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static inline __sum16 csum_fold(__wsum csum)
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{
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u32 sum = (__force u32)csum;
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sum = (sum & 0xffff) + (sum >> 16);
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sum = (sum & 0xffff) + (sum >> 16);
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return (__force __sum16)~sum;
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}
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#endif
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#ifndef csum_tcpudp_nofold
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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 __wsum
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csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
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__u8 proto, __wsum sum);
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#endif
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#ifndef csum_tcpudp_magic
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static inline __sum16
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csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
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__u8 proto, __wsum sum)
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{
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return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
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}
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#endif
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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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extern __sum16 ip_compute_csum(const void *buff, int len);
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#endif /* __ASM_GENERIC_CHECKSUM_H */
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