46 lines
1.0 KiB
Groff
46 lines
1.0 KiB
Groff
.TH ONEC_SUM 3
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.SH NAME
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oneC_sum \- One's complement internet checksum
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.SH SYNOPSIS
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.ft B
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.nf
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#define _MINIX_SOURCE 1
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#include <stddef.h>
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#include <sys/types.h>
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#include <net/gen/oneCsum.h>
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u16_t oneC_sum(u16_t \fIprev\fP, void *\fIdata\fP, size_t \fIsize\fP)
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.fi
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.ft R
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.SH DESCRIPTION
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.B OneC_sum
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is used to calculate the one's complement checksum needed for IP network
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packets.
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A good document about the Internet Checksum is RFC-1071 (Computing the
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Internet checksum).
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.PP
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.B OneC_sum
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expects three parameters:
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.TP 10
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.I prev
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The checksum of previous blocks of data that are to be included in the
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checksum.
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The value of prev in first call to oneC_sum should be 0.
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.TP
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.I data
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A pointer to the block of data.
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The data is interpreted as a series of 16 bit numbers in network byte order, but
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an odd number of bytes is also allowed.
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.TP
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.I size
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The size of the data in bytes.
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.SH "SEE ALSO"
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.BR ip (4).
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.br
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.B RFC-1071
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.SH AUTHOR
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Philip Homburg (philip@cs.vu.nl)
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.\"
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.\" $PchId: oneC_sum.3,v 1.3 1996/02/22 21:05:31 philip Exp $
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