docs/manual/mod/mod_reqtimeout.xml

<?xml version="1.0"?>
<!DOCTYPE modulesynopsis SYSTEM "../style/modulesynopsis.dtd">
<?xml-stylesheet type="text/xsl" href="../style/manual.en.xsl"?>
<!-- $LastChangedRevision$ -->

<!--
 Licensed to the Apache Software Foundation (ASF) under one or more
 contributor license agreements.  See the NOTICE file distributed with
 this work for additional information regarding copyright ownership.
 The ASF licenses this file to You under the Apache License, Version 2.0
 (the "License"); you may not use this file except in compliance with
 the License.  You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
-->

<modulesynopsis metafile="mod_reqtimeout.xml.meta">

<name>mod_reqtimeout</name>
<description>Set timeout and minimum data rate for receiving requests
</description>
<status>Extension</status>
<sourcefile>mod_reqtimeout.c</sourcefile>
<identifier>reqtimeout_module</identifier>

<summary>
    <p>This module provides a convenient way to set timeouts and minimum data
    rates for receiving requests. Should a timeout occur or a data rate be
    to low, the corresponding connection will be closed by the server.</p>

    <p>This is logged at <directive module="core">LogLevel</directive>
    <code>info</code>.</p>
    
    <p>If needed, the <directive module="core">LogLevel</directive> directive
    can be tweaked to explicitly log it:</p>
    <highlight language="config">
      LogLevel reqtimeout:info
    </highlight>
</summary>

<section id="examples"><title>Examples</title>

    <ol>
      <li>
        Allow for 5 seconds to complete the TLS handshake, 10 seconds to
        receive the request headers and 30 seconds for receiving the
        request body:

        <highlight language="config">
          RequestReadTimeout handshake=5 header=10 body=30
        </highlight>
      </li>

      <li>
        Allow at least 10 seconds to receive the request body.
        If the client sends data, increase the timeout by 1 second for every
        1000 bytes received, with no upper limit for the timeout (except for
        the limit given indirectly by
        <directive module="core">LimitRequestBody</directive>):

        <highlight language="config">
          RequestReadTimeout body=10,MinRate=1000
        </highlight>
      </li>

      <li>
        Allow at least 10 seconds to receive the request headers.
        If the client sends data, increase the timeout by 1 second for every
        500 bytes received. But do not allow more than 30 seconds for the
        request headers:

        <highlight language="config">
          RequestReadTimeout header=10-30,MinRate=500
        </highlight>
      </li>

      <li>
        Usually, a server should have both header and body timeouts configured.
        If a common configuration is used for http and https virtual hosts, the
        timeouts should not be set too low:

        <highlight language="config">
          RequestReadTimeout header=20-40,MinRate=500 body=20,MinRate=500
        </highlight>
      </li>

    </ol>
</section>

<directivesynopsis>
<name>RequestReadTimeout</name>
<description>Set timeout values for completing the TLS handshake, receiving
the request headers and/or body from client.
</description>
<syntax>RequestReadTimeout
[handshake=<var>timeout</var>[-<var>maxtimeout</var>][,MinRate=<var>rate</var>]
[header=<var>timeout</var>[-<var>maxtimeout</var>][,MinRate=<var>rate</var>]
[body=<var>timeout</var>[-<var>maxtimeout</var>][,MinRate=<var>rate</var>]
</syntax>
<default>RequestReadTimeout handshake=0 header=20-40,MinRate=500 body=20,MinRate=500</default>
<contextlist><context>server config</context><context>virtual host</context>
</contextlist>
<compatibility>Defaulted to disabled in version 2.3.14 and earlier. The
<code>handshake</code> stage is available since version 2.4.39.
</compatibility>

<usage>
    <p>This directive can set various timeouts for completing the TLS handshake,
    receiving the request headers and/or the request body from the client.
    If the client fails to complete each of these stages within the configured
    time, a <code>408 REQUEST TIME OUT</code> error is sent.</p>

    <p>For SSL virtual hosts, the <code>handshake</code> timeout values is the time
    needed to do the initial SSL handshake.  If the user's browser is configured to
    query certificate revocation lists and the CRL server is not reachable, the
    initial SSL handshake may take a significant time until the browser gives up
    waiting for the CRL.  Therefore the <code>handshake</code> timeout should take
    this possible overhead into consideration for SSL virtual hosts (if necessary).
    The body timeout values include the time needed for SSL renegotiation
    (if necessary).</p>

    <p>When an <directive module="core">AcceptFilter</directive> is in use
    (usually the case on Linux and FreeBSD), the socket is not sent to the
    server process before at least one byte (or the whole request for
    <code>httpready</code>) is received. The handshake and header timeouts
    configured with <directive>RequestReadTimeout</directive> are only effective
    after the server process has received the socket.</p>

    <p>When waiting for a subsequent request on a kept-alive
    connection, the timeout configured by <directive
    module="core">KeepAliveTimeout</directive> applies regardless of
    whether <directive>RequestReadTimeout</directive> is also
    used.</p>
    
    <p>For each of the three timeout stages (handshake, header or body), there are
    three ways to specify the timeout:
    </p>

    <ul>

    <li><strong>Fixed timeout value</strong>:<br />

    <example><var>stage</var>=<var>timeout</var></example>

    <p>The time in seconds allowed for completing the whole stage (handshaking,
    reading all of the request headers or body). A value of 0 means no limit.</p>
    </li>

    <li><strong>Disable module for a vhost</strong>:<br />

    <example>handshake=0 header=0 body=0</example>

    <p>This disables <module>mod_reqtimeout</module> completely (note that
    <code>handshake=0</code> is the default already and could be omitted).</p>
    </li>

    <li><strong>Timeout value that is increased when data is
    received</strong>:<br />
    <example>
    <var>stage</var>=<var>timeout</var>,MinRate=<var>data_rate</var>
    </example>

    <p>Same as above, but whenever data is received, the timeout value is
    increased according to the specified minimum data rate (in bytes per
    second).</p>
    </li>

    <li><strong>Timeout value that is increased when data is received, with an
    upper bound</strong>:<br />
    <example>
    <var>stage</var>=<var>timeout</var>-<var>maxtimeout</var>,MinRate=<var>data_rate</var>
    </example>

    <p>Same as above, but the timeout will not be increased above the second
    value of the specified timeout range.</p>
    </li>

    </ul>

</usage>

</directivesynopsis>

</modulesynopsis>