grepcidr.sgml

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<refentry>
  <refentryinfo>
    <author>
      <firstname>Jem</firstname>
      <surname>Berkes</surname>
    </author>
    <address>
      <email>jem@berkes.ca</email>
    </address>
    <copyright>
      <year>2013</year>
      <holder>Jem Berkes</holder>
    </copyright>
    <date>Jan 4, 2014</date>
  </refentryinfo>
  <refmeta>
    <refentrytitle>GREPCIDR</refentrytitle>
    <manvolnum>1</manvolnum>
  </refmeta>
  <refnamediv>
    <refname>grepcidr</refname>

    <refpurpose>Filter IPv4 and IPv6 addresses matching CIDR patterns</refpurpose>
  </refnamediv>
  <refsynopsisdiv>
    <cmdsynopsis>
      <command>grepcidr</command>
      <arg><option><replaceable>OPTIONS</replaceable></option></arg>
      <arg choice="req">PATTERN</arg>
	 <arg><option><replaceable>FILE...</replaceable></option></arg>
    </cmdsynopsis>
    <cmdsynopsis>
      <command>grepcidr</command>
      <arg><option><replaceable>OPTIONS</replaceable></option></arg>
      <arg><option>-e <replaceable>PATTERN</replaceable></option> | <option>-f <replaceable>PATFILE</replaceable></option></arg>
	 <arg><option><replaceable>FILE...</replaceable></option></arg>
    </cmdsynopsis>
  </refsynopsisdiv>
  <refsect1>
    <title>DESCRIPTION</title>
	<para>
	<command>grepcidr</command> can be used to filter a list of IP addresses against one or more
	Classless Inter-Domain Routing (CIDR) specifications.  As with grep, there
	are options to invert matching and load patterns from a file.  <command>grepcidr</command> is
	capable of efficiently processing large numbers of IPs and networks.
	</para>
  </refsect1>
  <refsect1>
    <title>OPTIONS</title>

    <variablelist>
      <varlistentry>
        <term><option>-V</option></term>
        <listitem>
          <para>Show software version</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><option>-c</option></term>
        <listitem>
          <para>Display count of the matching lines, instead of showing the lines</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><option>-i</option></term>
        <listitem>
          <para>Inverse match, include lines without an IP, implies -v</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><option>-s</option></term>
        <listitem>
          <para>Enforce strict alignment of CIDR mask; host portion must be all zero</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><option>-v</option></term>
        <listitem>
          <para>Invert the sense of matching, output lines with IPs that don't match</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><option>-x</option></term>
        <listitem>
          <para>Strict matching, only look at start of line</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><option>-e</option></term>
        <listitem>
          <para>Specify individual IP or CIDR pattern(s) on command-line</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><option>-f</option></term>
        <listitem>
          <para>Load individual IP or CIDR pattern(s) from file</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><option>-p</option></term>
        <listitem>
          <para>Output the pattern that matches a line, not the line itself</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>
  
  <refsect1>
	<title>USAGE NOTES</title>
	<para>
	PATTERN specified on the command line may contain multiple patterns
	separated by whitespace or commas. For long lists of network patterns,
	use <option>-f</option> to load a file where each line contains one pattern (can be IPv4
	or IPv6).  Blank lines and comments starting with # are ignored.
	</para>
	<para>Each IPv4 pattern, whether on command line or loaded from a file, may be:</para>
	<programlisting>
	a.b.c.d/xy        (CIDR format)
	a.b.c.d-e.f.g.h   (IP range)
	a.b.c.d           (Single IP)
	</programlisting>
	<para>And similarly for IPv6:</para>
	<programlisting>
	a:b:c::/xyz       (CIDR format)
	a:b:c::           (Single IP)
	</programlisting>
	<para>
	Dotted-decimal IPv4 format, or any legal IPv6 format is supported (see: man inet_pton).
	</para>
	<para>
	IP addresses that appear anywhere on the input line will be compared and
	matched against the patterns.  To be recognized, an IP (field) must end
	with terminating text.  An IPv4 field terminates upon anything other than
	alphanumeric or dot.  An IPv6 field terminates upon anything other than
	alphanumeric, dot, or colon.  This is to prevent accidental matching of
	ambiguous text such as host names containing reverse DNS.
	</para>
	<para>
	Use the <option>-x</option> option to do a strict parse without searching the whole line,
	and <command>grepcidr</command> will only look for the single IP at the start of the line.
	</para>
	
  </refsect1>


  <refsect1>
    <title>EXAMPLES</title>

    <para><emphasis><command>grepcidr</command> -f ournetworks blacklist &gt; abuse.log</emphasis></para>
    <para>Find customers (CIDR ranges in file) that appear in blacklist</para>
    
    <para><emphasis><command>grepcidr</command> 2001:db8::/32 log.1 log.2</emphasis></para>
    <para>Search for this IPv6 network inside two files</para>

    <para><emphasis><command>grepcidr</command> 127.0.0.0/8 iplog</emphasis></para>
    <para>Searches for any localnet IP addresses inside the iplog file</para>

    <para><emphasis><command>grepcidr</command> "192.168.0.1-192.168.10.13" iplog</emphasis></para>
    <para>Searches for IPs matching indicated range in the iplog file</para>

    <para><emphasis><command>script</command> | <command>grepcidr</command> -vf whitelist &gt; blacklist</emphasis></para>
    <para>Create a blacklist, with whitelisted networks removed (inverse)</para>

    <para><emphasis><command>grepcidr</command> -f list1 list2</emphasis></para>
    <para>Cross-reference two lists, outputs IPs common to both lists</para>

  </refsect1>

  <refsect1>
    <title>EXIT STATUS</title>
    <para>
	As with grep: the exit status is 0 if matching IPs are found, and 1
	if not found.  If an error occurred the exit status is 2. 
    </para>
  </refsect1>
  
  <refsect1>
    <title>AUTHOR</title>
    <para>This software and manual page was written by Jem Berkes &lt;jem@berkes.ca&gt;
	based on the first man page and DocBook format contributed by Ryan Finnie.
	Permission is granted to copy, distribute and/or modify this document under
	the terms of the GNU General Public License, Version 2 or any later version
	published by the Free Software Foundation.
	</para>
  </refsect1>

  <refsect1>
    <title>WEB SITE</title>
    <para>
	http://www.pc-tools.net/unix/grepcidr/
    </para>
  </refsect1>

  <refsect1>
	<title>THANKS</title>
	
	<para>
	Sponsored in part by the Spamhaus Project, http://www.spamhaus.org/
	</para>
	
	<para>
	Thanks to John Levine &lt;johnl@taugh.com&gt; for sharing his alternative
	implementation.  I used a couple ideas from his code, such as portable 128-bit
	numbers and support for multiple input files. However, John's version is quite
	different and represents a significant fork in the project.
	</para>
	
	<para>
	Thanks to Ryan Finnie &lt;ryan@finnie.org&gt; for his work on the Debian package.
	I've adopted several of his changes including the Makefile, and the DocBook
	format which now is the source of the man page.  Thanks to Ryan for writing
	the first manual in DocBook format.
	</para>

	<para>
	Many thanks to Dick Wesseling &lt;ftu@fi.uu.nl&gt; who suggested an improved data
	structure format as well as binary search, to improve grepcidr performance.
	</para>

  </refsect1>
</refentry>

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