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.TH CLICK-ALIGN 1 "27/Nov/1999" "Version \*V"
.SH NAME
click-align \- adds required Align elements to a Click configuration
'
.SH SYNOPSIS
.B click-align
.RI \%[ options ]
.RI \%[ router\-file ]
'
.SH DESCRIPTION
The
.B click-align
tool makes Click router configurations usable on machines that don't
support unaligned accesses. It reads a router configuration file in the
.M click 5
language, adds any required
.M Align n
elements, and writes the new configuration to the standard output.
.PP
Several Click elements, such as
.M CheckIPHeader n
and
.M ToLinux n ,
have alignment requirements. The CheckIPHeader element, for example,
expects that the packet begins with an IP header, and that this IP header
is four-byte-aligned. Normally, Click does not guarantee this: elements
cannot know how input packets will be aligned. The
.B click-align
tool first analyzes the router configuration, then inserts
.M Align n
elements as required to ensure that packets will be properly aligned. It
also adds an
.M AlignmentInfo n
element so elements can figure out what packet alignment they can expect.
.PP
The list of alignment requirements is currently built in to the
.B click-align
tool and cannot be changed except by recompilation.
'
.SH "OPTIONS"
'
If any filename argument is a single dash "-",
.B click-align
will use the standard input or output instead, as appropriate.
'
.TP 5
.BI \-f " file"
.PD 0
.TP
.BI \-\-file " file"
Read the router configuration to transform from
.IR file .
The default is the standard input.
'
.Sp
.TP
.BI \-e " expr"
.PD 0
.TP
.BI \-\-expr " expr"
Use
.IR expr ,
a string in the Click language, as the router configuration to transform.
'
.Sp
.TP
.BI \-o " file"
.TP
.BI \-\-output " file"
Write the output router configuration to
.IR file .
The default is the standard output.
'
.Sp
.TP 5
.BI \-\-help
Print usage information and exit.
'
.Sp
.TP
.BI \-\-version
Print the version number and some quickie warranty information and exit.
'
.PD
'
.SH "SEE ALSO"
.M click 5 ,
.M Align n ,
.M AlignmentInfo n
'
.SH AUTHOR
.na
Eddie Kohler, kohler@cs.ucla.edu
.br
http://www.pdos.lcs.mit.edu/click/
'