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<div class="section" id="examples">
<h1>Examples<a class="headerlink" href="#examples" title="Permalink to this headline">¶</a></h1>
<div class="section" id="rules">
<h2>Rules<a class="headerlink" href="#rules" title="Permalink to this headline">¶</a></h2>
<p>In <code class="docutils literal"><span class="pre">python-iptables</span></code>, you usually first create a rule, and set any
source/destination address, in/out interface and protocol specifiers, for
example:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">iptc</span>
<span class="gp">>>> </span><span class="n">rule</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Rule</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">in_interface</span> <span class="o">=</span> <span class="s2">"eth0"</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">src</span> <span class="o">=</span> <span class="s2">"192.168.1.0/255.255.255.0"</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">protocol</span> <span class="o">=</span> <span class="s2">"tcp"</span>
</pre></div>
</div>
<p>This creates a rule that will match TCP packets coming in on eth0, with a
source IP address of 192.168.1.0/255.255.255.0.</p>
<p>A rule may contain matches and a target. A match is like a filter matching
certain packet attributes, while a target tells what to do with the packet
(drop it, accept it, transform it somehow, etc). One can create a match or
target via a Rule:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">rule</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Rule</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">m</span> <span class="o">=</span> <span class="n">rule</span><span class="o">.</span><span class="n">create_match</span><span class="p">(</span><span class="s2">"tcp"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">t</span> <span class="o">=</span> <span class="n">rule</span><span class="o">.</span><span class="n">create_target</span><span class="p">(</span><span class="s2">"DROP"</span><span class="p">)</span>
</pre></div>
</div>
<p>Match and target parameters can be changed after creating them. It is also
perfectly valid to create a match or target via instantiating them with
their constructor, but you still need a rule and you have to add the matches
and the target to their rule manually:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">rule</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Rule</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">match</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Match</span><span class="p">(</span><span class="n">rule</span><span class="p">,</span> <span class="s2">"tcp"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">target</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Target</span><span class="p">(</span><span class="n">rule</span><span class="p">,</span> <span class="s2">"DROP"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">add_match</span><span class="p">(</span><span class="n">match</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">target</span> <span class="o">=</span> <span class="n">target</span>
</pre></div>
</div>
<p>Any parameters a match or target might take can be set via the attributes of
the object. To set the destination port for a TCP match:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">rule</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Rule</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">protocol</span> <span class="o">=</span> <span class="s2">"tcp"</span>
<span class="gp">>>> </span><span class="n">match</span> <span class="o">=</span> <span class="n">rule</span><span class="o">.</span><span class="n">create_match</span><span class="p">(</span><span class="s2">"tcp"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">match</span><span class="o">.</span><span class="n">dport</span> <span class="o">=</span> <span class="s2">"80"</span>
</pre></div>
</div>
<p>To set up a rule that matches packets marked with 0xff:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">rule</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Rule</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">protocol</span> <span class="o">=</span> <span class="s2">"tcp"</span>
<span class="gp">>>> </span><span class="n">match</span> <span class="o">=</span> <span class="n">rule</span><span class="o">.</span><span class="n">create_match</span><span class="p">(</span><span class="s2">"mark"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">match</span><span class="o">.</span><span class="n">mark</span> <span class="o">=</span> <span class="s2">"0xff"</span>
</pre></div>
</div>
<p>Parameters are always strings. You can supply any string as the parameter
value, but note that most extensions validate their parameters. For example
this:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">rule</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Rule</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">protocol</span> <span class="o">=</span> <span class="s2">"tcp"</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">target</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Target</span><span class="p">(</span><span class="n">rule</span><span class="p">,</span> <span class="s2">"ACCEPT"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">match</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Match</span><span class="p">(</span><span class="n">rule</span><span class="p">,</span> <span class="s2">"state"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">chain</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Chain</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">FILTER</span><span class="p">),</span> <span class="s2">"INPUT"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">match</span><span class="o">.</span><span class="n">state</span> <span class="o">=</span> <span class="s2">"RELATED,ESTABLISHED"</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">add_match</span><span class="p">(</span><span class="n">match</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">chain</span><span class="o">.</span><span class="n">insert_rule</span><span class="p">(</span><span class="n">rule</span><span class="p">)</span>
</pre></div>
</div>
<p>will work. However, if you change the <cite>state</cite> parameter:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">rule</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Rule</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">protocol</span> <span class="o">=</span> <span class="s2">"tcp"</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">target</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Target</span><span class="p">(</span><span class="n">rule</span><span class="p">,</span> <span class="s2">"ACCEPT"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">match</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Match</span><span class="p">(</span><span class="n">rule</span><span class="p">,</span> <span class="s2">"state"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">chain</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Chain</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">FILTER</span><span class="p">),</span> <span class="s2">"INPUT"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">match</span><span class="o">.</span><span class="n">state</span> <span class="o">=</span> <span class="s2">"RELATED,ESTABLISHED,FOOBAR"</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">add_match</span><span class="p">(</span><span class="n">match</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">chain</span><span class="o">.</span><span class="n">insert_rule</span><span class="p">(</span><span class="n">rule</span><span class="p">)</span>
</pre></div>
</div>
<p><code class="docutils literal"><span class="pre">python-iptables</span></code> will throw an exception:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">Traceback</span> <span class="p">(</span><span class="n">most</span> <span class="n">recent</span> <span class="n">call</span> <span class="n">last</span><span class="p">):</span>
<span class="n">File</span> <span class="s2">"state.py"</span><span class="p">,</span> <span class="n">line</span> <span class="mi">7</span><span class="p">,</span> <span class="ow">in</span> <span class="o"><</span><span class="n">module</span><span class="o">></span>
<span class="n">match</span><span class="o">.</span><span class="n">state</span> <span class="o">=</span> <span class="s2">"RELATED,ESTABLISHED,FOOBAR"</span>
<span class="n">File</span> <span class="s2">"/home/user/Projects/python-iptables/iptc/ip4tc.py"</span><span class="p">,</span> <span class="n">line</span> <span class="mi">369</span><span class="p">,</span> <span class="ow">in</span> <span class="fm">__setattr__</span>
<span class="bp">self</span><span class="o">.</span><span class="n">parse</span><span class="p">(</span><span class="n">name</span><span class="o">.</span><span class="n">replace</span><span class="p">(</span><span class="s2">"_"</span><span class="p">,</span> <span class="s2">"-"</span><span class="p">),</span> <span class="n">value</span><span class="p">)</span>
<span class="n">File</span> <span class="s2">"/home/user/Projects/python-iptables/iptc/ip4tc.py"</span><span class="p">,</span> <span class="n">line</span> <span class="mi">286</span><span class="p">,</span> <span class="ow">in</span> <span class="n">parse</span>
<span class="bp">self</span><span class="o">.</span><span class="n">_parse</span><span class="p">(</span><span class="n">argv</span><span class="p">,</span> <span class="n">inv</span><span class="p">,</span> <span class="n">entry</span><span class="p">)</span>
<span class="n">File</span> <span class="s2">"/home/user/Projects/python-iptables/iptc/ip4tc.py"</span><span class="p">,</span> <span class="n">line</span> <span class="mi">516</span><span class="p">,</span> <span class="ow">in</span> <span class="n">_parse</span>
<span class="n">ct</span><span class="o">.</span><span class="n">cast</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_ptrptr</span><span class="p">,</span> <span class="n">ct</span><span class="o">.</span><span class="n">POINTER</span><span class="p">(</span><span class="n">ct</span><span class="o">.</span><span class="n">c_void_p</span><span class="p">)))</span>
<span class="n">File</span> <span class="s2">"/home/user/Projects/python-iptables/iptc/xtables.py"</span><span class="p">,</span> <span class="n">line</span> <span class="mi">736</span><span class="p">,</span> <span class="ow">in</span> <span class="n">new</span>
<span class="n">ret</span> <span class="o">=</span> <span class="n">fn</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">)</span>
<span class="n">File</span> <span class="s2">"/home/user/Projects/python-iptables/iptc/xtables.py"</span><span class="p">,</span> <span class="n">line</span> <span class="mi">1031</span><span class="p">,</span> <span class="ow">in</span> <span class="n">parse_match</span>
<span class="n">argv</span><span class="p">[</span><span class="mi">1</span><span class="p">]))</span>
<span class="n">iptc</span><span class="o">.</span><span class="n">xtables</span><span class="o">.</span><span class="n">XTablesError</span><span class="p">:</span> <span class="n">state</span><span class="p">:</span> <span class="n">parameter</span> <span class="n">error</span> <span class="o">-</span><span class="mi">2</span> <span class="p">(</span><span class="n">RELATED</span><span class="p">,</span><span class="n">ESTABLISHED</span><span class="p">,</span><span class="n">FOOBAR</span><span class="p">)</span>
</pre></div>
</div>
<p>Certain parameters take a string that optionally consists of multiple words.
The comment match is a good example:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">rule</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Rule</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">src</span> <span class="o">=</span> <span class="s2">"127.0.0.1"</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">protocol</span> <span class="o">=</span> <span class="s2">"udp"</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">target</span> <span class="o">=</span> <span class="n">rule</span><span class="o">.</span><span class="n">create_target</span><span class="p">(</span><span class="s2">"ACCEPT"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">match</span> <span class="o">=</span> <span class="n">rule</span><span class="o">.</span><span class="n">create_match</span><span class="p">(</span><span class="s2">"comment"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">match</span><span class="o">.</span><span class="n">comment</span> <span class="o">=</span> <span class="s2">"this is a test comment"</span>
<span class="gp">>>> </span><span class="n">chain</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Chain</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">FILTER</span><span class="p">),</span> <span class="s2">"INPUT"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">chain</span><span class="o">.</span><span class="n">insert_rule</span><span class="p">(</span><span class="n">rule</span><span class="p">)</span>
</pre></div>
</div>
<p>Note that this is still just one parameter value.</p>
<p>However, when a match or a target takes multiple parameter values, that needs
to be passed in as a list. Let’s assume you have created and set up an
<code class="docutils literal"><span class="pre">ipset</span></code> called <code class="docutils literal"><span class="pre">blacklist</span></code> via the <code class="docutils literal"><span class="pre">ipset</span></code> command. To create a rule
with a match for this set:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">rule</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Rule</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">m</span> <span class="o">=</span> <span class="n">rule</span><span class="o">.</span><span class="n">create_match</span><span class="p">(</span><span class="s2">"set"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">m</span><span class="o">.</span><span class="n">match_set</span> <span class="o">=</span> <span class="p">[</span><span class="s1">'blacklist'</span><span class="p">,</span> <span class="s1">'src'</span><span class="p">]</span>
</pre></div>
</div>
<p>Note how this time a list was used for the parameter value, since the <code class="docutils literal"><span class="pre">set</span></code>
match <code class="docutils literal"><span class="pre">match_set</span></code> parameter expects two values. See the <code class="docutils literal"><span class="pre">iptables</span></code>
manpages to find out what the extensions you use expect. See <a class="reference external" href="http://ipset.netfilter.org/">ipset</a> for more
information.</p>
<p>When you are ready constructing your rule, add them to the chain you want it
to show up in:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">chain</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Chain</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">FILTER</span><span class="p">),</span> <span class="s2">"INPUT"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">chain</span><span class="o">.</span><span class="n">insert_rule</span><span class="p">(</span><span class="n">rule</span><span class="p">)</span>
</pre></div>
</div>
<p>This will put your rule into the INPUT chain in the filter table.</p>
</div>
<div class="section" id="chains-and-tables">
<h2>Chains and tables<a class="headerlink" href="#chains-and-tables" title="Permalink to this headline">¶</a></h2>
<p>You can of course also check what a rule’s source/destination address,
in/out inteface etc is. To print out all rules in the FILTER table:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">iptc</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">FILTER</span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">for</span> <span class="n">chain</span> <span class="ow">in</span> <span class="n">table</span><span class="o">.</span><span class="n">chains</span><span class="p">:</span>
<span class="gp">>>> </span> <span class="nb">print</span> <span class="s2">"======================="</span>
<span class="gp">>>> </span> <span class="nb">print</span> <span class="s2">"Chain "</span><span class="p">,</span> <span class="n">chain</span><span class="o">.</span><span class="n">name</span>
<span class="gp">>>> </span> <span class="k">for</span> <span class="n">rule</span> <span class="ow">in</span> <span class="n">chain</span><span class="o">.</span><span class="n">rules</span><span class="p">:</span>
<span class="gp">>>> </span> <span class="nb">print</span> <span class="s2">"Rule"</span><span class="p">,</span> <span class="s2">"proto:"</span><span class="p">,</span> <span class="n">rule</span><span class="o">.</span><span class="n">protocol</span><span class="p">,</span> <span class="s2">"src:"</span><span class="p">,</span> <span class="n">rule</span><span class="o">.</span><span class="n">src</span><span class="p">,</span> <span class="s2">"dst:"</span><span class="p">,</span> \
<span class="gp">>>> </span> <span class="n">rule</span><span class="o">.</span><span class="n">dst</span><span class="p">,</span> <span class="s2">"in:"</span><span class="p">,</span> <span class="n">rule</span><span class="o">.</span><span class="n">in_interface</span><span class="p">,</span> <span class="s2">"out:"</span><span class="p">,</span> <span class="n">rule</span><span class="o">.</span><span class="n">out_interface</span><span class="p">,</span>
<span class="gp">>>> </span> <span class="nb">print</span> <span class="s2">"Matches:"</span><span class="p">,</span>
<span class="gp">>>> </span> <span class="k">for</span> <span class="n">match</span> <span class="ow">in</span> <span class="n">rule</span><span class="o">.</span><span class="n">matches</span><span class="p">:</span>
<span class="gp">>>> </span> <span class="nb">print</span> <span class="n">match</span><span class="o">.</span><span class="n">name</span><span class="p">,</span>
<span class="gp">>>> </span> <span class="nb">print</span> <span class="s2">"Target:"</span><span class="p">,</span>
<span class="gp">>>> </span> <span class="nb">print</span> <span class="n">rule</span><span class="o">.</span><span class="n">target</span><span class="o">.</span><span class="n">name</span>
<span class="gp">>>> </span><span class="nb">print</span> <span class="s2">"======================="</span>
</pre></div>
</div>
<p>As you see in the code snippet above, rules are organized into chains, and
chains are in tables. You have a fixed set of tables; for IPv4:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="o">*</span> <span class="n">FILTER</span><span class="p">,</span>
<span class="o">*</span> <span class="n">NAT</span><span class="p">,</span>
<span class="o">*</span> <span class="n">MANGLE</span> <span class="ow">and</span>
<span class="o">*</span> <span class="n">RAW</span><span class="o">.</span>
</pre></div>
</div>
<p>For IPv6 the tables are:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="o">*</span> <span class="n">FILTER</span><span class="p">,</span>
<span class="o">*</span> <span class="n">MANGLE</span><span class="p">,</span>
<span class="o">*</span> <span class="n">RAW</span> <span class="ow">and</span>
<span class="o">*</span> <span class="n">SECURITY</span><span class="o">.</span>
</pre></div>
</div>
<p>To access a table:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">iptc</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">FILTER</span><span class="p">)</span>
<span class="gp">>>> </span><span class="nb">print</span> <span class="n">table</span><span class="o">.</span><span class="n">name</span>
<span class="go">filter</span>
</pre></div>
</div>
<p>To create a new chain in the FILTER table:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">iptc</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">FILTER</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">chain</span> <span class="o">=</span> <span class="n">table</span><span class="o">.</span><span class="n">create_chain</span><span class="p">(</span><span class="s2">"testchain"</span><span class="p">)</span>
<span class="go">$ sudo iptables -L -n</span>
<span class="go">[...]</span>
<span class="go">Chain testchain (0 references)</span>
<span class="go">target prot opt source destination</span>
</pre></div>
</div>
<p>To access an existing chain:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">iptc</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">FILTER</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">chain</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Chain</span><span class="p">(</span><span class="n">table</span><span class="p">,</span> <span class="s2">"INPUT"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">chain</span><span class="o">.</span><span class="n">name</span>
<span class="go">'INPUT'</span>
<span class="gp">>>> </span><span class="nb">len</span><span class="p">(</span><span class="n">chain</span><span class="o">.</span><span class="n">rules</span><span class="p">)</span>
<span class="go">10</span>
<span class="go">>>></span>
</pre></div>
</div>
</div>
<div class="section" id="more-about-matches-and-targets">
<h2>More about matches and targets<a class="headerlink" href="#more-about-matches-and-targets" title="Permalink to this headline">¶</a></h2>
<p>There are basic targets, such as <code class="docutils literal"><span class="pre">DROP</span></code> and <code class="docutils literal"><span class="pre">ACCEPT</span></code>. E.g. to reject
packets with source address <code class="docutils literal"><span class="pre">127.0.0.1/255.0.0.0</span></code> coming in on any of the
<code class="docutils literal"><span class="pre">eth</span></code> interfaces:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">iptc</span>
<span class="gp">>>> </span><span class="n">chain</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Chain</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">FILTER</span><span class="p">),</span> <span class="s2">"INPUT"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">rule</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Rule</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">in_interface</span> <span class="o">=</span> <span class="s2">"eth+"</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">src</span> <span class="o">=</span> <span class="s2">"127.0.0.1/255.0.0.0"</span>
<span class="gp">>>> </span><span class="n">target</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Target</span><span class="p">(</span><span class="n">rule</span><span class="p">,</span> <span class="s2">"DROP"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">target</span> <span class="o">=</span> <span class="n">target</span>
<span class="gp">>>> </span><span class="n">chain</span><span class="o">.</span><span class="n">insert_rule</span><span class="p">(</span><span class="n">rule</span><span class="p">)</span>
</pre></div>
</div>
<p>To instantiate a target or match, we can either create an object like above,
or use the <code class="docutils literal"><span class="pre">rule.create_target(target_name)</span></code> and
<code class="docutils literal"><span class="pre">rule.create_match(match_name)</span></code> methods. For example, in the code above
target could have been created as:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">target</span> <span class="o">=</span> <span class="n">rule</span><span class="o">.</span><span class="n">create_target</span><span class="p">(</span><span class="s2">"DROP"</span><span class="p">)</span>
</pre></div>
</div>
<p>instead of:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">target</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Target</span><span class="p">(</span><span class="n">rule</span><span class="p">,</span> <span class="s2">"DROP"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">target</span> <span class="o">=</span> <span class="n">target</span>
</pre></div>
</div>
<p>The former also adds the match or target to the rule, saving a call.</p>
<p>Another example, using a target which takes parameters. Let’s mark packets
going to <code class="docutils literal"><span class="pre">192.168.1.2</span></code> UDP port <code class="docutils literal"><span class="pre">1234</span></code> with <code class="docutils literal"><span class="pre">0xffff</span></code>:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">iptc</span>
<span class="gp">>>> </span><span class="n">chain</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Chain</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">MANGLE</span><span class="p">),</span> <span class="s2">"PREROUTING"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">rule</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Rule</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">dst</span> <span class="o">=</span> <span class="s2">"192.168.1.2"</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">protocol</span> <span class="o">=</span> <span class="s2">"udp"</span>
<span class="gp">>>> </span><span class="n">match</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Match</span><span class="p">(</span><span class="n">rule</span><span class="p">,</span> <span class="s2">"udp"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">match</span><span class="o">.</span><span class="n">dport</span> <span class="o">=</span> <span class="s2">"1234"</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">add_match</span><span class="p">(</span><span class="n">match</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">target</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Target</span><span class="p">(</span><span class="n">rule</span><span class="p">,</span> <span class="s2">"MARK"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">target</span><span class="o">.</span><span class="n">set_mark</span> <span class="o">=</span> <span class="s2">"0xffff"</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">target</span> <span class="o">=</span> <span class="n">target</span>
<span class="gp">>>> </span><span class="n">chain</span><span class="o">.</span><span class="n">insert_rule</span><span class="p">(</span><span class="n">rule</span><span class="p">)</span>
</pre></div>
</div>
<p>Matches are optional (specifying a target is mandatory). E.g. to insert a rule
to NAT TCP packets going out via <code class="docutils literal"><span class="pre">eth0</span></code>:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">iptc</span>
<span class="gp">>>> </span><span class="n">chain</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Chain</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">NAT</span><span class="p">),</span> <span class="s2">"POSTROUTING"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">rule</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Rule</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">protocol</span> <span class="o">=</span> <span class="s2">"tcp"</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">out_interface</span> <span class="o">=</span> <span class="s2">"eth0"</span>
<span class="gp">>>> </span><span class="n">target</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Target</span><span class="p">(</span><span class="n">rule</span><span class="p">,</span> <span class="s2">"MASQUERADE"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">target</span><span class="o">.</span><span class="n">to_ports</span> <span class="o">=</span> <span class="s2">"1234"</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">target</span> <span class="o">=</span> <span class="n">target</span>
<span class="gp">>>> </span><span class="n">chain</span><span class="o">.</span><span class="n">insert_rule</span><span class="p">(</span><span class="n">rule</span><span class="p">)</span>
</pre></div>
</div>
<p>Here only the properties of the rule decide whether the rule will be applied
to a packet.</p>
<p>Matches are optional, but we can add multiple matches to a rule. In the
following example we will do that, using the <code class="docutils literal"><span class="pre">iprange</span></code> and the <code class="docutils literal"><span class="pre">tcp</span></code>
matches:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">iptc</span>
<span class="gp">>>> </span><span class="n">rule</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Rule</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">protocol</span> <span class="o">=</span> <span class="s2">"tcp"</span>
<span class="gp">>>> </span><span class="n">match</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Match</span><span class="p">(</span><span class="n">rule</span><span class="p">,</span> <span class="s2">"tcp"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">match</span><span class="o">.</span><span class="n">dport</span> <span class="o">=</span> <span class="s2">"22"</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">add_match</span><span class="p">(</span><span class="n">match</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">match</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Match</span><span class="p">(</span><span class="n">rule</span><span class="p">,</span> <span class="s2">"iprange"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">match</span><span class="o">.</span><span class="n">src_range</span> <span class="o">=</span> <span class="s2">"192.168.1.100-192.168.1.200"</span>
<span class="gp">>>> </span><span class="n">match</span><span class="o">.</span><span class="n">dst_range</span> <span class="o">=</span> <span class="s2">"172.22.33.106"</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">add_match</span><span class="p">(</span><span class="n">match</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">target</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Target</span><span class="p">(</span><span class="n">rule</span><span class="p">,</span> <span class="s2">"DROP"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">chain</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Chain</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">FILTER</span><span class="p">),</span> <span class="s2">"INPUT"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">chain</span><span class="o">.</span><span class="n">insert_rule</span><span class="p">(</span><span class="n">rule</span><span class="p">)</span>
</pre></div>
</div>
<p>This is the <code class="docutils literal"><span class="pre">python-iptables</span></code> equivalent of the following iptables command:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="c1"># iptables -A INPUT -p tcp –destination-port 22 -m iprange –src-range 192.168.1.100-192.168.1.200 –dst-range 172.22.33.106 -j DROP</span>
</pre></div>
</div>
<p>You can of course negate matches, just like when you use <code class="docutils literal"><span class="pre">!</span></code> in front of a
match with iptables. For example:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">iptc</span>
<span class="gp">>>> </span><span class="n">rule</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Rule</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">match</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Match</span><span class="p">(</span><span class="n">rule</span><span class="p">,</span> <span class="s2">"mac"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">match</span><span class="o">.</span><span class="n">mac_source</span> <span class="o">=</span> <span class="s2">"!00:11:22:33:44:55"</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">add_match</span><span class="p">(</span><span class="n">match</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">rule</span><span class="o">.</span><span class="n">target</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Target</span><span class="p">(</span><span class="n">rule</span><span class="p">,</span> <span class="s2">"ACCEPT"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">chain</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Chain</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">FILTER</span><span class="p">),</span> <span class="s2">"INPUT"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">chain</span><span class="o">.</span><span class="n">insert_rule</span><span class="p">(</span><span class="n">rule</span><span class="p">)</span>
</pre></div>
</div>
<p>This results in:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span>$ sudo iptables -L -n
Chain INPUT (policy ACCEPT)
target prot opt source destination
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 MAC ! 00:11:22:33:44:55
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
</pre></div>
</div>
</div>
<div class="section" id="counters">
<h2>Counters<a class="headerlink" href="#counters" title="Permalink to this headline">¶</a></h2>
<p>You can query rule and chain counters, e.g.:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">iptc</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">FILTER</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">chain</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Chain</span><span class="p">(</span><span class="n">table</span><span class="p">,</span> <span class="s1">'OUTPUT'</span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">for</span> <span class="n">rule</span> <span class="ow">in</span> <span class="n">chain</span><span class="o">.</span><span class="n">rules</span><span class="p">:</span>
<span class="gp">>>> </span> <span class="p">(</span><span class="n">packets</span><span class="p">,</span> <span class="nb">bytes</span><span class="p">)</span> <span class="o">=</span> <span class="n">rule</span><span class="o">.</span><span class="n">get_counters</span><span class="p">()</span>
<span class="gp">>>> </span> <span class="nb">print</span> <span class="n">packets</span><span class="p">,</span> <span class="nb">bytes</span>
</pre></div>
</div>
<p>However, the counters are only refreshed when the underlying low-level
iptables connection is refreshed in <code class="docutils literal"><span class="pre">Table</span></code> via <code class="docutils literal"><span class="pre">table.refresh()</span></code>. For
example:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">time</span><span class="o">,</span> <span class="nn">sys</span>
<span class="gp">>>> </span><span class="kn">import</span> <span class="nn">iptc</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">FILTER</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">chain</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Chain</span><span class="p">(</span><span class="n">table</span><span class="p">,</span> <span class="s1">'OUTPUT'</span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">for</span> <span class="n">rule</span> <span class="ow">in</span> <span class="n">chain</span><span class="o">.</span><span class="n">rules</span><span class="p">:</span>
<span class="gp">>>> </span> <span class="p">(</span><span class="n">packets</span><span class="p">,</span> <span class="nb">bytes</span><span class="p">)</span> <span class="o">=</span> <span class="n">rule</span><span class="o">.</span><span class="n">get_counters</span><span class="p">()</span>
<span class="gp">>>> </span> <span class="nb">print</span> <span class="n">packets</span><span class="p">,</span> <span class="nb">bytes</span>
<span class="gp">>>> </span><span class="nb">print</span> <span class="s2">"Please send some traffic"</span>
<span class="gp">>>> </span><span class="n">sys</span><span class="o">.</span><span class="n">stdout</span><span class="o">.</span><span class="n">flush</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mi">3</span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">for</span> <span class="n">rule</span> <span class="ow">in</span> <span class="n">chain</span><span class="o">.</span><span class="n">rules</span><span class="p">:</span>
<span class="gp">>>> </span> <span class="c1"># Here you will get back the same counter values as above</span>
<span class="gp">>>> </span> <span class="p">(</span><span class="n">packets</span><span class="p">,</span> <span class="nb">bytes</span><span class="p">)</span> <span class="o">=</span> <span class="n">rule</span><span class="o">.</span><span class="n">get_counters</span><span class="p">()</span>
<span class="gp">>>> </span> <span class="nb">print</span> <span class="n">packets</span><span class="p">,</span> <span class="nb">bytes</span>
</pre></div>
</div>
<p>This will show you the same counter values even if there was traffic hitting
your rules. You have to refresh your table to get update your counters:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">time</span><span class="o">,</span> <span class="nn">sys</span>
<span class="gp">>>> </span><span class="kn">import</span> <span class="nn">iptc</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">FILTER</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">chain</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Chain</span><span class="p">(</span><span class="n">table</span><span class="p">,</span> <span class="s1">'OUTPUT'</span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">for</span> <span class="n">rule</span> <span class="ow">in</span> <span class="n">chain</span><span class="o">.</span><span class="n">rules</span><span class="p">:</span>
<span class="gp">>>> </span> <span class="p">(</span><span class="n">packets</span><span class="p">,</span> <span class="nb">bytes</span><span class="p">)</span> <span class="o">=</span> <span class="n">rule</span><span class="o">.</span><span class="n">get_counters</span><span class="p">()</span>
<span class="gp">>>> </span> <span class="nb">print</span> <span class="n">packets</span><span class="p">,</span> <span class="nb">bytes</span>
<span class="gp">>>> </span><span class="nb">print</span> <span class="s2">"Please send some traffic"</span>
<span class="gp">>>> </span><span class="n">sys</span><span class="o">.</span><span class="n">stdout</span><span class="o">.</span><span class="n">flush</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mi">3</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">table</span><span class="o">.</span><span class="n">refresh</span><span class="p">()</span> <span class="c1"># Here: refresh table to update rule counters</span>
<span class="gp">>>> </span><span class="k">for</span> <span class="n">rule</span> <span class="ow">in</span> <span class="n">chain</span><span class="o">.</span><span class="n">rules</span><span class="p">:</span>
<span class="gp">>>> </span> <span class="p">(</span><span class="n">packets</span><span class="p">,</span> <span class="nb">bytes</span><span class="p">)</span> <span class="o">=</span> <span class="n">rule</span><span class="o">.</span><span class="n">get_counters</span><span class="p">()</span>
<span class="gp">>>> </span> <span class="nb">print</span> <span class="n">packets</span><span class="p">,</span> <span class="nb">bytes</span>
</pre></div>
</div>
<p>What is more, if you add:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">iptables</span> <span class="o">-</span><span class="n">A</span> <span class="n">OUTPUT</span> <span class="o">-</span><span class="n">p</span> <span class="n">tcp</span> <span class="o">--</span><span class="n">sport</span> <span class="mi">80</span>
<span class="n">iptables</span> <span class="o">-</span><span class="n">A</span> <span class="n">OUTPUT</span> <span class="o">-</span><span class="n">p</span> <span class="n">tcp</span> <span class="o">--</span><span class="n">sport</span> <span class="mi">22</span>
</pre></div>
</div>
<p>you can query rule and chain counters together with the protocol and sport(or
dport), e.g.:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">iptc</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">FILTER</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">chain</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Chain</span><span class="p">(</span><span class="n">table</span><span class="p">,</span> <span class="s1">'OUTPUT'</span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">for</span> <span class="n">rule</span> <span class="ow">in</span> <span class="n">chain</span><span class="o">.</span><span class="n">rules</span><span class="p">:</span>
<span class="gp">>>> </span> <span class="k">for</span> <span class="n">match</span> <span class="ow">in</span> <span class="n">rule</span><span class="o">.</span><span class="n">matches</span><span class="p">:</span>
<span class="gp">>>> </span> <span class="p">(</span><span class="n">packets</span><span class="p">,</span> <span class="nb">bytes</span><span class="p">)</span> <span class="o">=</span> <span class="n">rule</span><span class="o">.</span><span class="n">get_counters</span><span class="p">()</span>
<span class="gp">>>> </span> <span class="nb">print</span> <span class="n">packets</span><span class="p">,</span> <span class="nb">bytes</span><span class="p">,</span> <span class="n">match</span><span class="o">.</span><span class="n">name</span><span class="p">,</span> <span class="n">match</span><span class="o">.</span><span class="n">sport</span>
</pre></div>
</div>
</div>
<div class="section" id="autocommit">
<h2>Autocommit<a class="headerlink" href="#autocommit" title="Permalink to this headline">¶</a></h2>
<p><code class="docutils literal"><span class="pre">Python-iptables</span></code> by default automatically performs an iptables commit after
each operation. That is, after you add a rule in <code class="docutils literal"><span class="pre">python-iptables</span></code>, that
will take effect immediately.</p>
<p>It may happen that you want to batch together certain operations. A typical
use case is traversing a chain and removing rules matching a specific
criteria. If you do this with autocommit enabled, after the first delete
operation, your chain’s state will change and you have to restart the
traversal. You can do something like this:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">iptc</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">FILTER</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">removed</span> <span class="o">=</span> <span class="kc">True</span>
<span class="gp">>>> </span><span class="n">chain</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Chain</span><span class="p">(</span><span class="n">table</span><span class="p">,</span> <span class="s2">"FORWARD"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">while</span> <span class="n">removed</span> <span class="o">==</span> <span class="kc">True</span><span class="p">:</span>
<span class="gp">>>> </span> <span class="n">removed</span> <span class="o">=</span> <span class="kc">False</span>
<span class="gp">>>> </span> <span class="k">for</span> <span class="n">rule</span> <span class="ow">in</span> <span class="n">chain</span><span class="o">.</span><span class="n">rules</span><span class="p">:</span>
<span class="gp">>>> </span> <span class="k">if</span> <span class="n">rule</span><span class="o">.</span><span class="n">out_interface</span> <span class="ow">and</span> <span class="s2">"eth0"</span> <span class="ow">in</span> <span class="n">rule</span><span class="o">.</span><span class="n">out_interface</span><span class="p">:</span>
<span class="gp">>>> </span> <span class="n">chain</span><span class="o">.</span><span class="n">delete_rule</span><span class="p">(</span><span class="n">rule</span><span class="p">)</span>
<span class="gp">>>> </span> <span class="n">removed</span> <span class="o">=</span> <span class="kc">True</span>
<span class="gp">>>> </span> <span class="k">break</span>
</pre></div>
</div>
<p>This is clearly not ideal and the code is not very readable. An alternative is
to disable autocommits, traverse the chain, removing one or more rules, than
commit it:</p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">iptc</span>
<span class="gp">>>> </span><span class="n">table</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="p">(</span><span class="n">iptc</span><span class="o">.</span><span class="n">Table</span><span class="o">.</span><span class="n">FILTER</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">table</span><span class="o">.</span><span class="n">autocommit</span> <span class="o">=</span> <span class="kc">False</span>
<span class="gp">>>> </span><span class="n">chain</span> <span class="o">=</span> <span class="n">iptc</span><span class="o">.</span><span class="n">Chain</span><span class="p">(</span><span class="n">table</span><span class="p">,</span> <span class="s2">"FORWARD"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="k">for</span> <span class="n">rule</span> <span class="ow">in</span> <span class="n">chain</span><span class="o">.</span><span class="n">rules</span><span class="p">:</span>
<span class="gp">>>> </span> <span class="k">if</span> <span class="n">rule</span><span class="o">.</span><span class="n">out_interface</span> <span class="ow">and</span> <span class="s2">"eth0"</span> <span class="ow">in</span> <span class="n">rule</span><span class="o">.</span><span class="n">out_interface</span><span class="p">:</span>
<span class="gp">>>> </span> <span class="n">chain</span><span class="o">.</span><span class="n">delete_rule</span><span class="p">(</span><span class="n">rule</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">table</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">table</span><span class="o">.</span><span class="n">autocommit</span> <span class="o">=</span> <span class="kc">True</span>
</pre></div>
</div>
<p>The drawback is that <cite>Table</cite> is a singleton, and if you disable autocommit, it
will be disabled for all instances of that <cite>Table</cite>.</p>
</div>
</div>
</div>
</div>
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<h3><a href="index.html">Table Of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">Examples</a><ul>
<li><a class="reference internal" href="#rules">Rules</a></li>
<li><a class="reference internal" href="#chains-and-tables">Chains and tables</a></li>
<li><a class="reference internal" href="#more-about-matches-and-targets">More about matches and targets</a></li>
<li><a class="reference internal" href="#counters">Counters</a></li>
<li><a class="reference internal" href="#autocommit">Autocommit</a></li>
</ul>
</li>
</ul>
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