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<?xml version='1.0'?> <!--*-nxml-*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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Copyright 2010 Lennart Poettering
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<refentry id="systemd.socket">
<refentryinfo>
<title>systemd.socket</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Lennart</firstname>
<surname>Poettering</surname>
<email>lennart@poettering.net</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>systemd.socket</refentrytitle>
<manvolnum>5</manvolnum>
</refmeta>
<refnamediv>
<refname>systemd.socket</refname>
<refpurpose>Socket unit configuration</refpurpose>
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</refnamediv>
<refsynopsisdiv>
<para><filename><replaceable>socket</replaceable>.socket</filename></para>
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</refsynopsisdiv>
<refsect1>
<title>Description</title>
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<para>A unit configuration file whose name ends in
<literal>.socket</literal> encodes information about
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an IPC or network socket or a file system FIFO
controlled and supervised by systemd, for socket-based
activation.</para>
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<para>This man page lists the configuration options
specific to this unit type. See
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
for the common options of all unit configuration
files. The common configuration items are configured
in the generic [Unit] and [Install] sections. The
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socket specific configuration options are configured
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in the [Socket] section.</para>
<para>Additional options are listed in
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
which define the execution environment the
<option>ExecStartPre=</option>,
<option>ExecStartPost=</option>,
<option>ExecStopPre=</option> and
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<option>ExecStopPost=</option> commands are executed
in, and in
<citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
which define the way the processes are terminated, and
in
<citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
which configure resource control settings for the
processes of the socket.</para>
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<para>For each socket file, a matching service file
must exist, describing the service to start on
incoming traffic on the socket (see
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<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
for more information about .service files). The name
of the .service unit is by default the same as the
name of the .socket unit, but can be altered with the
<option>Service=</option> option described below.
Depending on the setting of the <option>Accept=</option>
option described below, this .service unit must either
be named like the .socket unit, but with the suffix
replaced, unless overridden with
<option>Service=</option>; or it must be a template
unit named the same way. Example: a socket file
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<filename>foo.socket</filename> needs a matching
service <filename>foo.service</filename> if
<option>Accept=false</option> is set. If
<option>Accept=true</option> is set, a service
template file <filename>foo@.service</filename> must
exist from which services are instantiated for each
incoming connection.</para>
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<para>Unless <varname>DefaultDependencies=</varname>
is set to <option>false</option>, socket units will
implicitly have dependencies of type
<varname>Requires=</varname> and
<varname>After=</varname> on
<filename>sysinit.target</filename> as well as
dependencies of type <varname>Conflicts=</varname> and
<varname>Before=</varname> on
<filename>shutdown.target</filename>. These ensure
that socket units pull in basic system
initialization, and are terminated cleanly prior to
system shutdown. Only sockets involved with early
boot or late system shutdown should disable this
option.</para>
<para>Socket units will have a
<varname>Before=</varname> dependency on the service
which they trigger added implicitly. No implicit
<varname>WantedBy=</varname> or
<varname>RequiredBy=</varname> dependency from the
socket to the service is added. This means that the
service may be started without the socket, in which
case it must be able to open sockets by itself. To
prevent this, an explicit <varname>Requires=</varname>
dependency may be added.</para>
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<para>Socket units may be used to implement on-demand
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starting of services, as well as parallelized starting
of services. See the blog stories linked at the end
for an introduction.</para>
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<para>Note that the daemon software configured for
socket activation with socket units needs to be able
to accept sockets from systemd, either via systemd's
native socket passing interface (see
<citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
for details) or via the traditional
<citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>-style
socket passing (i.e. sockets passed in via standard input and
output, using <varname>StandardInput=socket</varname>
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in the service file).</para>
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</refsect1>
<refsect1>
<title>Options</title>
<para>Socket files must include a [Socket] section,
which carries information about the socket or FIFO it
supervises. A number of options that may be used in
this section are shared with other unit types. These
options are documented in
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
and
<citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
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options specific to the [Socket] section of socket
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units are the following:</para>
<variablelist class='unit-directives'>
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<varlistentry>
<term><varname>ListenStream=</varname></term>
<term><varname>ListenDatagram=</varname></term>
<term><varname>ListenSequentialPacket=</varname></term>
<listitem><para>Specifies an address
to listen on for a stream
(<constant>SOCK_STREAM</constant>), datagram (<constant>SOCK_DGRAM</constant>),
or sequential packet
(<constant>SOCK_SEQPACKET</constant>) socket, respectively. The address
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can be written in various formats:</para>
<para>If the address starts with a
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slash (<literal>/</literal>), it is read as file system
socket in the <constant>AF_UNIX</constant> socket
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family.</para>
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<para>If the address starts with an at
symbol (<literal>@</literal>), it is read as abstract
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namespace socket in the
<constant>AF_UNIX</constant>
family. The <literal>@</literal> is
replaced with a
<constant>NUL</constant> character
before binding. For details, see
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<citerefentry><refentrytitle>unix</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
<para>If the address string is a
single number, it is read as port
number to listen on via
IPv6. Depending on the value of
<varname>BindIPv6Only=</varname> (see below) this
might result in the service being
available via both IPv6 and IPv4 (default) or
just via IPv6.
</para>
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<para>If the address string is a
string in the format v.w.x.y:z, it is
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read as IPv4 specifier for listening
on an address v.w.x.y on a port
z.</para>
<para>If the address string is a
string in the format [x]:y, it is read
as IPv6 address x on a port y. Note
that this might make the service
available via IPv4, too, depending on
the <varname>BindIPv6Only=</varname>
setting (see below).
</para>
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<para>Note that <constant>SOCK_SEQPACKET</constant>
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(i.e. <varname>ListenSequentialPacket=</varname>)
is only available for <constant>AF_UNIX</constant>
sockets. <constant>SOCK_STREAM</constant>
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(i.e. <varname>ListenStream=</varname>)
when used for IP sockets refers to TCP
sockets, <constant>SOCK_DGRAM</constant>
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(i.e. <varname>ListenDatagram=</varname>)
to UDP.</para>
<para>These options may be specified
more than once in which case incoming
traffic on any of the sockets will
trigger service activation, and all
listed sockets will be passed to the
service, regardless of whether there is
incoming traffic on them or not. If
the empty string is assigned to any of
these options, the list of addresses
to listen on is reset, all prior uses
of any of these options will have no
effect.</para>
<para>It is also possible to have more
than one socket unit for the same
service when using
<varname>Service=</varname>, and the
service will receive all the sockets
configured in all the socket units.
Sockets configured in one unit are
passed in the order of configuration,
but no ordering between socket units
is specified.</para>
<para>If an IP address is used here,
it is often desirable to listen on it
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before the interface it is configured
on is up and running, and even
regardless of whether it will be up and
running at any point. To deal with this,
it is recommended to set the
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<varname>FreeBind=</varname> option
described below.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>ListenFIFO=</varname></term>
<listitem><para>Specifies a file
system FIFO to listen on. This expects
an absolute file system path as
argument. Behavior otherwise is very
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similar to the
<varname>ListenDatagram=</varname>
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directive above.</para></listitem>
</varlistentry>
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<varlistentry>
<term><varname>ListenSpecial=</varname></term>
<listitem><para>Specifies a special
file in the file system to listen
on. This expects an absolute file
system path as argument. Behavior
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otherwise is very similar to the
<varname>ListenFIFO=</varname>
directive above. Use this to open
character device nodes as well as
special files in
<filename>/proc</filename> and
<filename>/sys</filename>.</para></listitem>
</varlistentry>
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<varlistentry>
<term><varname>ListenNetlink=</varname></term>
<listitem><para>Specifies a Netlink
family to create a socket for to
listen on. This expects a short string
referring to the <constant>AF_NETLINK</constant> family
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name (such as <varname>audit</varname>
or <varname>kobject-uevent</varname>)
as argument, optionally suffixed by a
whitespace followed by a multicast
group integer. Behavior otherwise is
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very similar to the
<varname>ListenDatagram=</varname>
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directive above.</para></listitem>
</varlistentry>
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<varlistentry>
<term><varname>ListenMessageQueue=</varname></term>
<listitem><para>Specifies a POSIX
message queue name to listen on. This
expects a valid message queue name
(i.e. beginning with /). Behavior
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otherwise is very similar to the
<varname>ListenFIFO=</varname>
directive above. On Linux message
queue descriptors are actually file
descriptors and can be inherited
between processes.</para></listitem>
</varlistentry>
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<varlistentry>
<term><varname>BindIPv6Only=</varname></term>
<listitem><para>Takes a one of
<option>default</option>,
<option>both</option> or
<option>ipv6-only</option>. Controls
the IPV6_V6ONLY socket option (see
<citerefentry><refentrytitle>ipv6</refentrytitle><manvolnum>7</manvolnum></citerefentry>
for details). If
<option>both</option>, IPv6 sockets
bound will be accessible via both IPv4
and IPv6. If
<option>ipv6-only</option>, they will
be accessible via IPv6 only. If
<option>default</option> (which is the
default, surprise!), the system wide
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default setting is used, as controlled
by
<filename>/proc/sys/net/ipv6/bindv6only</filename>,
which in turn defaults to the
equivalent of
<option>both</option>.</para>
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</listitem>
</varlistentry>
<varlistentry>
<term><varname>Backlog=</varname></term>
<listitem><para>Takes an unsigned
integer argument. Specifies the number
of connections to queue that have not
been accepted yet. This setting
matters only for stream and sequential
packet sockets. See
<citerefentry><refentrytitle>listen</refentrytitle><manvolnum>2</manvolnum></citerefentry>
for details. Defaults to SOMAXCONN
(128).</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>BindToDevice=</varname></term>
<listitem><para>Specifies a network
interface name to bind this socket
to. If set, traffic will only be
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accepted from the specified network
interfaces. This controls the
SO_BINDTODEVICE socket option (see
<citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
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for details). If this option is used,
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an automatic dependency from this
socket unit on the network interface
device unit
(<citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>
is created.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>DirectoryMode=</varname></term>
<listitem><para>If listening on a file
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system socket or FIFO, the parent
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directories are automatically created
if needed. This option specifies the
file system access mode used when
creating these directories. Takes an
access mode in octal
notation. Defaults to
0755.</para></listitem>
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</varlistentry>
<varlistentry>
<term><varname>SocketMode=</varname></term>
<listitem><para>If listening on a file
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system socket or FIFO, this option
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specifies the file system access mode
used when creating the file
node. Takes an access mode in octal
notation. Defaults to
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0666.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>Accept=</varname></term>
<listitem><para>Takes a boolean
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argument. If true, a service instance
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is spawned for each incoming
connection and only the connection
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socket is passed to it. If false, all
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listening sockets themselves are
passed to the started service unit,
and only one service unit is spawned
for all connections (also see
above). This value is ignored for
datagram sockets and FIFOs where a
single service unit unconditionally
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handles all incoming traffic. Defaults
to <option>false</option>. For
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performance reasons, it is recommended
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to write new daemons only in a way
that is suitable for
<option>Accept=false</option>. A
daemon listening on an <constant>AF_UNIX</constant> socket
may, but does not need to, call
<citerefentry><refentrytitle>close</refentrytitle><manvolnum>2</manvolnum></citerefentry>
on the received socket before
exiting. However, it must not unlink
the socket from a file system. It
should not invoke
<citerefentry><refentrytitle>shutdown</refentrytitle><manvolnum>2</manvolnum></citerefentry>
on sockets it got with
<varname>Accept=false</varname>, but
it may do so for sockets it got with
<varname>Accept=true</varname> set.
Setting <varname>Accept=true</varname>
is mostly useful to allow daemons
designed for usage with
<citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>
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to work unmodified with systemd socket
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activation.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>MaxConnections=</varname></term>
<listitem><para>The maximum number of
connections to simultaneously run
services instances for, when
<option>Accept=true</option> is
set. If more concurrent connections
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are coming in, they will be refused
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until at least one existing connection
is terminated. This setting has no
effect on sockets configured with
<option>Accept=false</option> or datagram
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sockets. Defaults to
64.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>KeepAlive=</varname></term>
<listitem><para>Takes a boolean
argument. If true, the TCP/IP stack
will send a keep alive message after
2h (depending on the configuration of
<filename>/proc/sys/net/ipv4/tcp_keepalive_time</filename>)
for all TCP streams accepted on this
socket. This controls the SO_KEEPALIVE
socket option (see
<citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
and the <ulink
url="http://www.tldp.org/HOWTO/html_single/TCP-Keepalive-HOWTO/">TCP
Keepalive HOWTO</ulink> for details.)
Defaults to
<option>false</option>.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>Priority=</varname></term>
<listitem><para>Takes an integer
argument controlling the priority for
all traffic sent from this
socket. This controls the SO_PRIORITY
socket option (see
<citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
for details.).</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>ReceiveBuffer=</varname></term>
<term><varname>SendBuffer=</varname></term>
<listitem><para>Takes an integer
argument controlling the receive or
send buffer sizes of this socket,
respectively. This controls the
SO_RCVBUF and SO_SNDBUF socket options
(see
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<citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
for details.). The usual suffixes K,
M, G are supported and are understood
to the base of 1024.</para></listitem>
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</varlistentry>
<varlistentry>
<term><varname>IPTOS=</varname></term>
<listitem><para>Takes an integer
argument controlling the IP
Type-Of-Service field for packets
generated from this socket. This
controls the IP_TOS socket option (see
<citerefentry><refentrytitle>ip</refentrytitle><manvolnum>7</manvolnum></citerefentry>
for details.). Either a numeric string
or one of <option>low-delay</option>,
<option>throughput</option>,
<option>reliability</option> or
<option>low-cost</option> may be
specified.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>IPTTL=</varname></term>
<listitem><para>Takes an integer
argument controlling the IPv4
Time-To-Live/IPv6 Hop-Count field for
packets generated from this
socket. This sets the
IP_TTL/IPV6_UNICAST_HOPS socket
options (see
<citerefentry><refentrytitle>ip</refentrytitle><manvolnum>7</manvolnum></citerefentry>
and
<citerefentry><refentrytitle>ipv6</refentrytitle><manvolnum>7</manvolnum></citerefentry>
for details.)</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>Mark=</varname></term>
<listitem><para>Takes an integer
value. Controls the firewall mark of
packets generated by this socket. This
can be used in the firewall logic to
filter packets from this socket. This
sets the SO_MARK socket option. See
<citerefentry><refentrytitle>iptables</refentrytitle><manvolnum>8</manvolnum></citerefentry>
for details.</para></listitem>
</varlistentry>
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<varlistentry>
<term><varname>ReusePort=</varname></term>
<listitem><para>Takes a boolean
value. If true, allows multiple <citerefentry><refentrytitle>bind</refentrytitle><manvolnum>2</manvolnum></citerefentry>s
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to this TCP or UDP port. This
controls the SO_REUSEPORT socket
option. See
<citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
for details.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>SmackLabel=</varname></term>
<term><varname>SmackLabelIPIn=</varname></term>
<term><varname>SmackLabelIPOut=</varname></term>
<listitem><para>Takes a string
value. Controls the extended
attributes
<literal>security.SMACK64</literal>,
<literal>security.SMACK64IPIN</literal>
and
<literal>security.SMACK64IPOUT</literal>,
respectively, i.e. the security label
of the FIFO, or the security label for
the incoming or outgoing connections
of the socket, respectively. See
<ulink
url="https://www.kernel.org/doc/Documentation/security/Smack.txt">Smack.txt</ulink>
for details.</para></listitem>
</varlistentry>
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<varlistentry>
<term><varname>PipeSize=</varname></term>
<listitem><para>Takes an size in
bytes. Controls the pipe buffer size
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of FIFOs configured in this socket
unit. See
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<citerefentry><refentrytitle>fcntl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
for details. The usual suffixes K, M,
G are supported and are understood to
the base of 1024.</para></listitem>
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</varlistentry>
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<varlistentry>
<term><varname>MessageQueueMaxMessages=</varname>,
<varname>MessageQueueMessageSize=</varname></term>
<listitem><para>These two settings
take integer values and control the
mq_maxmsg field or the mq_msgsize field, respectively, when
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creating the message queue. Note that
either none or both of these variables
need to be set. See
<citerefentry><refentrytitle>mq_setattr</refentrytitle><manvolnum>3</manvolnum></citerefentry>
for details.</para></listitem>
</varlistentry>
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<varlistentry>
<term><varname>FreeBind=</varname></term>
<listitem><para>Takes a boolean
value. Controls whether the socket can
be bound to non-local IP
addresses. This is useful to configure
sockets listening on specific IP
addresses before those IP addresses
are successfully configured on a
network interface. This sets the
IP_FREEBIND socket option. For
robustness reasons it is recommended
to use this option whenever you bind a
socket to a specific IP
address. Defaults to <option>false</option>.</para></listitem>
</varlistentry>
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<varlistentry>
<term><varname>Transparent=</varname></term>
<listitem><para>Takes a boolean
value. Controls the IP_TRANSPARENT
socket option. Defaults to
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<option>false</option>.</para></listitem>
</varlistentry>
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<varlistentry>
<term><varname>Broadcast=</varname></term>
<listitem><para>Takes a boolean
value. This controls the SO_BROADCAST
socket option, which allows broadcast
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datagrams to be sent from this
socket. Defaults to
<option>false</option>.</para></listitem>
</varlistentry>
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<varlistentry>
<term><varname>PassCredentials=</varname></term>
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<listitem><para>Takes a boolean
value. This controls the SO_PASSCRED
socket option, which allows <constant>AF_UNIX</constant> sockets to
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receive the credentials of the sending
process in an ancillary message.
Defaults to
<option>false</option>.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>PassSecurity=</varname></term>
<listitem><para>Takes a boolean
value. This controls the SO_PASSSEC
socket option, which allows <constant>AF_UNIX</constant>
sockets to receive the security
context of the sending process in an
ancillary message. Defaults to
<option>false</option>.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>TCPCongestion=</varname></term>
<listitem><para>Takes a string
value. Controls the TCP congestion
algorithm used by this socket. Should
be one of "westwood", "veno", "cubic",
"lp" or any other available algorithm
supported by the IP stack. This
setting applies only to stream
sockets.</para></listitem>
</varlistentry>
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<varlistentry>
<term><varname>ExecStartPre=</varname></term>
<term><varname>ExecStartPost=</varname></term>
<listitem><para>Takes one or more
command lines, which are executed
before or after the listening
sockets/FIFOs are created and
bound, respectively. The first token of the command
line must be an absolute filename,
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then followed by arguments for the
process. Multiple command lines may be
specified following the same scheme as
used for
<varname>ExecStartPre=</varname> of
service unit files.</para></listitem>
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</varlistentry>
<varlistentry>
<term><varname>ExecStopPre=</varname></term>
<term><varname>ExecStopPost=</varname></term>
<listitem><para>Additional commands
that are executed before or after
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the listening sockets/FIFOs are closed
and removed, respectively. Multiple command lines
may be specified following the same
scheme as used for
<varname>ExecStartPre=</varname> of
service unit files.</para></listitem>
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</varlistentry>
<varlistentry>
<term><varname>TimeoutSec=</varname></term>
<listitem><para>Configures the time to
wait for the commands specified in
<varname>ExecStartPre=</varname>,
<varname>ExecStartPost=</varname>,
<varname>ExecStopPre=</varname> and
<varname>ExecStopPost=</varname> to
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finish. If a command does not exit
within the configured time, the socket
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will be considered failed and be shut
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down again. All commands still running,
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will be terminated forcibly via
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<constant>SIGTERM</constant>, and after another delay of
this time with <constant>SIGKILL</constant>. (See
<option>KillMode=</option> in <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>.)
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Takes a unit-less value in seconds, or
a time span value such as "5min
20s". Pass 0 to disable the timeout
logic. Defaults to <varname>TimeoutStartSec=</varname> from the
manager configuration file.</para></listitem>
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</varlistentry>
<varlistentry>
<term><varname>Service=</varname></term>
<listitem><para>Specifies the service
unit name to activate on incoming
traffic. This setting is only allowed
for sockets with
<varname>Accept=no</varname>. It
defaults to the service that bears the
same name as the socket (with the
suffix replaced). In most cases, it
should not be necessary to use this
option.</para></listitem>
</varlistentry>
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</variablelist>
<para>Check
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
and
<citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
for more settings.</para>
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</refsect1>
<refsect1>
<title>See Also</title>
<para>
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
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</para>
<para>
For more extensive descriptions see the "systemd for Developers" series:
<ulink url="http://0pointer.de/blog/projects/socket-activation.html">Socket Activation</ulink>,
<ulink url="http://0pointer.de/blog/projects/socket-activation2.html">Socket Activation, part II</ulink>,
<ulink url="http://0pointer.de/blog/projects/inetd.html">Converting inetd Services</ulink>,
<ulink url="http://0pointer.de/blog/projects/socket-activated-containers.html">Socket Activated Internet Services and OS Containers</ulink>.
</para>
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</refsect1>
</refentry>