<box begindoc>**This is automatically generated documentation.**  Edit after the "[[#COMMENTS|COMMENTS]]" heading; changes to the main body will be lost.</box>

====== click-fastclassifier ======

specializes Classifier code in a Click configuration

===== SYNOPSIS =====

**click-fastclassifier** 
[//options//]
[//param//=//value// ...]
[//router-file//]

===== DESCRIPTION =====

The
**click-fastclassifier** 
tool speeds up a Click configuration by creating fast versions of all its
[[:elements/Classifier|Classifier]],
[[:elements/IPClassifier|IPClassifier]],
and
[[:elements/IPFilter|IPFilter]]
elements. It reads a router configuration file in the
[[language]]
language and creates specialized C%%+%%+ source code for each Classifier-like
element. A Classifier is expanded into a series of if statements; for
example, the expansion of 'Classifier(0/80, -%%)%%' contains something like
this function:

  inline void
  FastClassifier_a_ac::length_unchecked_push(Packet *p)
  {
    const unsigned *data = (const unsigned *)(p->data() - 0);
   step_0:
    if ((data[0] & 255U) == 128U) {
      output(0).push(p);
      return;
    }
    output(1).push(p);
    return;
  }

After creating the source code,
**click-fastclassifier** 
will optionally compile it into dynamically loadable packages. The
Classifier elements in the input configuration are changed to use new
FastClassifier elements, and the resulting configuration, plus source code
and any compiled packages, are combined into an archive and written to the
standard output. You can install such an archive into the
[[linuxmodule]]
Linux kernel module with
[[click-install]]:\\
\\

    % click-fastclassifier -k CONFIGURATION | click-install

The
[[userdriver]]
user level driver can read the archives directly.

The
**click-fastclassifier** 
transformation can be reversed with the
**--reverse** 
option.

===== OPTIONS =====

If any filename argument is a single dash "-",
**click-fastclassifier** 
will use the standard input or output instead, as appropriate.

 ? **-f** //file// \\ **--file** //file//
 ! Read the router configuration to transform from //file//. The default is the standard input.
 ? **-e** //expr// \\ **--expression** //expr//
 ! Use //expr//, a string in the Click language, as the router configuration to transform.
 ? **-o** //file// \\ **--output** //file//
 ! Write the output router configuration to //file//. The default is the standard output.
 ? **-k**, **--kernel**
 ! Generate a dynamically loadable package for the [[linuxmodule]] Linux kernel module.
 ? **-u**, **--user**
 ! Generate a dynamically loadable package for the [[userdriver]] user-level driver.
 ? **-s**, **--source**
 ! Output only the source code for the FastClassifier elements.
 ? **-c**, **--config**
 ! Output only the new configuration (the one that includes FastClassifiers).
 ? **-r**, **--reverse**
 ! Reverse the tranformation. That is, remove any existing FastClassifier elements and replace them with equivalent Classifiers.
 ? **-q**, **--quiet**
 ! Compile code quietly (without echoing commands or top-level warnings).
 ? **--help**
 ! Print usage information and exit.
 ? **--version**
 ! Print the version number and some quickie warranty information and exit.

===== SEE ALSO =====

[[userdriver]],
[[click-devirtualize]],
[[click-install]],
[[language]],
[[linuxmodule]],
[[:elements/Classifier|Classifier]],
[[:elements/IPClassifier|IPClassifier]],
[[:elements/IPFilter|IPFilter]]

===== AUTHOR =====

Eddie Kohler, kohler@cs.ucla.edu\\
[[http://www.pdos.lcs.mit.edu/click/|http://www.pdos.lcs.mit.edu/click/]]


===== COMMENTS =====