1<html><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968"><title>bpf_check_classic</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="index.html" title="Linux Networking and Network Devices APIs"><link rel="up" href="ch01s03.html" title="Socket Filter"><link rel="prev" href="API-sk-filter.html" title="sk_filter"><link rel="next" href="API-bpf-prog-create.html" title="bpf_prog_create"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span class="phrase">bpf_check_classic</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="API-sk-filter.html">Prev</a>&#160;</td><th width="60%" align="center">Socket Filter</th><td width="20%" align="right">&#160;<a accesskey="n" href="API-bpf-prog-create.html">Next</a></td></tr></table><hr></div><div class="refentry"><a name="API-bpf-check-classic"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>bpf_check_classic &#8212; 
2     verify socket filter code
3 </p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">bpf_check_classic </b>(</code></td><td>const struct sock_filter * <var class="pdparam">filter</var>, </td></tr><tr><td>&#160;</td><td>unsigned int <var class="pdparam">flen</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer">&#160;</div></div></div><div class="refsect1"><a name="idp1096676828"></a><h2>Arguments</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="parameter"><code>filter</code></em></span></dt><dd><p>
4     filter to verify
5    </p></dd><dt><span class="term"><em class="parameter"><code>flen</code></em></span></dt><dd><p>
6     length of filter
7    </p></dd></dl></div></div><div class="refsect1"><a name="idp1096679452"></a><h2>Description</h2><p>
8   Check the user's filter code. If we let some ugly
9   filter code slip through kaboom! The filter must contain
10   no references or jumps that are out of range, no illegal
11   instructions, and must end with a RET instruction.
12   </p><p>
13
14   All jumps are forward as they are not signed.
15   </p><p>
16
17   Returns 0 if the rule set is legal or -EINVAL if not.
18</p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="API-sk-filter.html">Prev</a>&#160;</td><td width="20%" align="center"><a accesskey="u" href="ch01s03.html">Up</a></td><td width="40%" align="right">&#160;<a accesskey="n" href="API-bpf-prog-create.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top"><span class="phrase">sk_filter</span>&#160;</td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top">&#160;<span class="phrase">bpf_prog_create</span></td></tr></table></div></body></html>
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