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1 | <?xml version='1.0'?> <!--*-nxml-*--> |
2 | <?xml-stylesheet type="text/xsl" href="http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl"?> | |
3 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" | |
4 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> | |
5 | ||
6 | <!-- | |
7 | This file is part of systemd. | |
8 | ||
9 | Copyright 2010 Lennart Poettering | |
10 | ||
11 | systemd is free software; you can redistribute it and/or modify it | |
5430f7f2 LP |
12 | under the terms of the GNU Lesser General Public License as published by |
13 | the Free Software Foundation; either version 2.1 of the License, or | |
1f812fea LP |
14 | (at your option) any later version. |
15 | ||
16 | systemd is distributed in the hope that it will be useful, but | |
17 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
5430f7f2 | 19 | Lesser General Public License for more details. |
1f812fea | 20 | |
5430f7f2 | 21 | You should have received a copy of the GNU Lesser General Public License |
1f812fea LP |
22 | along with systemd; If not, see <http://www.gnu.org/licenses/>. |
23 | --> | |
24 | ||
25 | <refentry id="systemd.socket"> | |
26 | <refentryinfo> | |
27 | <title>systemd.socket</title> | |
28 | <productname>systemd</productname> | |
29 | ||
30 | <authorgroup> | |
31 | <author> | |
32 | <contrib>Developer</contrib> | |
33 | <firstname>Lennart</firstname> | |
34 | <surname>Poettering</surname> | |
35 | <email>lennart@poettering.net</email> | |
36 | </author> | |
37 | </authorgroup> | |
38 | </refentryinfo> | |
39 | ||
40 | <refmeta> | |
41 | <refentrytitle>systemd.socket</refentrytitle> | |
42 | <manvolnum>5</manvolnum> | |
43 | </refmeta> | |
44 | ||
45 | <refnamediv> | |
46 | <refname>systemd.socket</refname> | |
34511ca7 | 47 | <refpurpose>Socket unit configuration</refpurpose> |
1f812fea LP |
48 | </refnamediv> |
49 | ||
50 | <refsynopsisdiv> | |
e670b166 | 51 | <para><filename><replaceable>socket</replaceable>.socket</filename></para> |
1f812fea LP |
52 | </refsynopsisdiv> |
53 | ||
54 | <refsect1> | |
55 | <title>Description</title> | |
56 | ||
65232ea7 | 57 | <para>A unit configuration file whose name ends in |
479fe882 | 58 | <literal>.socket</literal> encodes information about |
65232ea7 LP |
59 | an IPC or network socket or a file system FIFO |
60 | controlled and supervised by systemd, for socket-based | |
61 | activation.</para> | |
1f812fea LP |
62 | |
63 | <para>This man page lists the configuration options | |
64 | specific to this unit type. See | |
65 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
66 | for the common options of all unit configuration | |
67 | files. The common configuration items are configured | |
68 | in the generic [Unit] and [Install] sections. The | |
cdb788e4 | 69 | socket specific configuration options are configured |
1f812fea LP |
70 | in the [Socket] section.</para> |
71 | ||
72 | <para>Additional options are listed in | |
ba60f905 LP |
73 | <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
74 | which define the execution environment the | |
75 | <option>ExecStartPre=</option>, | |
76 | <option>ExecStartPost=</option>, | |
77 | <option>ExecStopPre=</option> and | |
89ca6994 | 78 | <option>ExecStopPost=</option> commands are executed |
4819ff03 | 79 | in, and in |
d868475a | 80 | <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
3fde5f30 LP |
81 | which define the way the processes are terminated, and |
82 | in | |
83 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
84 | which configure resource control settings for the | |
85 | processes of the socket.</para> | |
1f812fea | 86 | |
73e231ab | 87 | <para>For each socket file, a matching service file |
3cf148f3 ZJS |
88 | must exist, describing the service to start on |
89 | incoming traffic on the socket (see | |
65232ea7 | 90 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
3cf148f3 ZJS |
91 | for more information about .service files). The name |
92 | of the .service unit is by default the same as the | |
66f756d4 | 93 | name of the .socket unit, but can be altered with the |
3cf148f3 | 94 | <option>Service=</option> option described below. |
66f756d4 | 95 | Depending on the setting of the <option>Accept=</option> |
3cf148f3 ZJS |
96 | option described below, this .service unit must either |
97 | be named like the .socket unit, but with the suffix | |
98 | replaced, unless overridden with | |
99 | <option>Service=</option>; or it must be a template | |
100 | unit named the same way. Example: a socket file | |
1f812fea LP |
101 | <filename>foo.socket</filename> needs a matching |
102 | service <filename>foo.service</filename> if | |
103 | <option>Accept=false</option> is set. If | |
3cf148f3 ZJS |
104 | <option>Accept=true</option> is set, a service |
105 | template file <filename>foo@.service</filename> must | |
106 | exist from which services are instantiated for each | |
107 | incoming connection.</para> | |
65232ea7 | 108 | |
62adf224 LP |
109 | <para>Unless <varname>DefaultDependencies=</varname> |
110 | is set to <option>false</option>, socket units will | |
111 | implicitly have dependencies of type | |
112 | <varname>Requires=</varname> and | |
113 | <varname>After=</varname> on | |
114 | <filename>sysinit.target</filename> as well as | |
115 | dependencies of type <varname>Conflicts=</varname> and | |
116 | <varname>Before=</varname> on | |
117 | <filename>shutdown.target</filename>. These ensure | |
118 | that socket units pull in basic system | |
119 | initialization, and are terminated cleanly prior to | |
120 | system shutdown. Only sockets involved with early | |
121 | boot or late system shutdown should disable this | |
122 | option.</para> | |
123 | ||
b200a92c JSJ |
124 | <para>Socket units will have a |
125 | <varname>Before=</varname> dependency on the service | |
126 | which they trigger added implicitly. No implicit | |
127 | <varname>WantedBy=</varname> or | |
128 | <varname>RequiredBy=</varname> dependency from the | |
129 | socket to the service is added. This means that the | |
130 | service may be started without the socket, in which | |
131 | case it must be able to open sockets by itself. To | |
132 | prevent this, an explicit <varname>Requires=</varname> | |
133 | dependency may be added.</para> | |
3cf148f3 | 134 | |
65232ea7 | 135 | <para>Socket units may be used to implement on-demand |
b439c6ee | 136 | starting of services, as well as parallelized starting |
3cf148f3 | 137 | of services. See the blog stories linked at the end |
66f756d4 | 138 | for an introduction.</para> |
be039669 LP |
139 | |
140 | <para>Note that the daemon software configured for | |
141 | socket activation with socket units needs to be able | |
142 | to accept sockets from systemd, either via systemd's | |
143 | native socket passing interface (see | |
144 | <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
145 | for details) or via the traditional | |
146 | <citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>-style | |
6db27428 ZJS |
147 | socket passing (i.e. sockets passed in via standard input and |
148 | output, using <varname>StandardInput=socket</varname> | |
be039669 | 149 | in the service file).</para> |
1f812fea LP |
150 | </refsect1> |
151 | ||
152 | <refsect1> | |
153 | <title>Options</title> | |
154 | ||
155 | <para>Socket files must include a [Socket] section, | |
156 | which carries information about the socket or FIFO it | |
157 | supervises. A number of options that may be used in | |
158 | this section are shared with other unit types. These | |
159 | options are documented in | |
4819ff03 LP |
160 | <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
161 | and | |
162 | <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The | |
65232ea7 | 163 | options specific to the [Socket] section of socket |
1f812fea LP |
164 | units are the following:</para> |
165 | ||
ccc9a4f9 | 166 | <variablelist class='unit-directives'> |
1f812fea LP |
167 | <varlistentry> |
168 | <term><varname>ListenStream=</varname></term> | |
169 | <term><varname>ListenDatagram=</varname></term> | |
170 | <term><varname>ListenSequentialPacket=</varname></term> | |
171 | <listitem><para>Specifies an address | |
172 | to listen on for a stream | |
74d00578 | 173 | (<constant>SOCK_STREAM</constant>), datagram (<constant>SOCK_DGRAM</constant>), |
16dad32e | 174 | or sequential packet |
74d00578 | 175 | (<constant>SOCK_SEQPACKET</constant>) socket, respectively. The address |
1f812fea LP |
176 | can be written in various formats:</para> |
177 | ||
178 | <para>If the address starts with a | |
05cc7267 | 179 | slash (<literal>/</literal>), it is read as file system |
74d00578 | 180 | socket in the <constant>AF_UNIX</constant> socket |
1f812fea LP |
181 | family.</para> |
182 | ||
05cc7267 | 183 | <para>If the address starts with an at |
79640424 | 184 | symbol (<literal>@</literal>), it is read as abstract |
05cc7267 ZJS |
185 | namespace socket in the |
186 | <constant>AF_UNIX</constant> | |
187 | family. The <literal>@</literal> is | |
188 | replaced with a | |
189 | <constant>NUL</constant> character | |
79640424 | 190 | before binding. For details, see |
1f812fea LP |
191 | <citerefentry><refentrytitle>unix</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> |
192 | ||
193 | <para>If the address string is a | |
79640424 | 194 | single number, it is read as port |
5198dabc LP |
195 | number to listen on via |
196 | IPv6. Depending on the value of | |
197 | <varname>BindIPv6Only=</varname> (see below) this | |
198 | might result in the service being | |
199 | available via both IPv6 and IPv4 (default) or | |
200 | just via IPv6. | |
201 | </para> | |
1f812fea LP |
202 | |
203 | <para>If the address string is a | |
79640424 | 204 | string in the format v.w.x.y:z, it is |
1f812fea LP |
205 | read as IPv4 specifier for listening |
206 | on an address v.w.x.y on a port | |
207 | z.</para> | |
208 | ||
209 | <para>If the address string is a | |
79640424 | 210 | string in the format [x]:y, it is read |
5198dabc LP |
211 | as IPv6 address x on a port y. Note |
212 | that this might make the service | |
213 | available via IPv4, too, depending on | |
214 | the <varname>BindIPv6Only=</varname> | |
215 | setting (see below). | |
216 | </para> | |
1f812fea | 217 | |
74d00578 | 218 | <para>Note that <constant>SOCK_SEQPACKET</constant> |
1f812fea | 219 | (i.e. <varname>ListenSequentialPacket=</varname>) |
74d00578 ZJS |
220 | is only available for <constant>AF_UNIX</constant> |
221 | sockets. <constant>SOCK_STREAM</constant> | |
1f812fea LP |
222 | (i.e. <varname>ListenStream=</varname>) |
223 | when used for IP sockets refers to TCP | |
74d00578 | 224 | sockets, <constant>SOCK_DGRAM</constant> |
1f812fea LP |
225 | (i.e. <varname>ListenDatagram=</varname>) |
226 | to UDP.</para> | |
227 | ||
228 | <para>These options may be specified | |
229 | more than once in which case incoming | |
74051b9b LP |
230 | traffic on any of the sockets will |
231 | trigger service activation, and all | |
232 | listed sockets will be passed to the | |
494a6682 | 233 | service, regardless of whether there is |
74051b9b LP |
234 | incoming traffic on them or not. If |
235 | the empty string is assigned to any of | |
236 | these options, the list of addresses | |
237 | to listen on is reset, all prior uses | |
238 | of any of these options will have no | |
239 | effect.</para> | |
240 | ||
3cf148f3 ZJS |
241 | <para>It is also possible to have more |
242 | than one socket unit for the same | |
243 | service when using | |
244 | <varname>Service=</varname>, and the | |
245 | service will receive all the sockets | |
246 | configured in all the socket units. | |
247 | Sockets configured in one unit are | |
248 | passed in the order of configuration, | |
249 | but no ordering between socket units | |
250 | is specified.</para> | |
251 | ||
74051b9b LP |
252 | <para>If an IP address is used here, |
253 | it is often desirable to listen on it | |
1f812fea LP |
254 | before the interface it is configured |
255 | on is up and running, and even | |
494a6682 | 256 | regardless of whether it will be up and |
73e231ab | 257 | running at any point. To deal with this, |
74051b9b | 258 | it is recommended to set the |
1f812fea LP |
259 | <varname>FreeBind=</varname> option |
260 | described below.</para></listitem> | |
261 | </varlistentry> | |
262 | ||
263 | <varlistentry> | |
264 | <term><varname>ListenFIFO=</varname></term> | |
265 | <listitem><para>Specifies a file | |
266 | system FIFO to listen on. This expects | |
267 | an absolute file system path as | |
c5315881 | 268 | argument. Behavior otherwise is very |
1f812fea LP |
269 | similar to the |
270 | <varname>ListenDatagram=</varname> | |
7a22745a LP |
271 | directive above.</para></listitem> |
272 | </varlistentry> | |
273 | ||
b0a3f2bc LP |
274 | <varlistentry> |
275 | <term><varname>ListenSpecial=</varname></term> | |
276 | <listitem><para>Specifies a special | |
277 | file in the file system to listen | |
278 | on. This expects an absolute file | |
c5315881 | 279 | system path as argument. Behavior |
b0a3f2bc LP |
280 | otherwise is very similar to the |
281 | <varname>ListenFIFO=</varname> | |
282 | directive above. Use this to open | |
283 | character device nodes as well as | |
284 | special files in | |
285 | <filename>/proc</filename> and | |
286 | <filename>/sys</filename>.</para></listitem> | |
287 | </varlistentry> | |
288 | ||
7a22745a LP |
289 | <varlistentry> |
290 | <term><varname>ListenNetlink=</varname></term> | |
291 | <listitem><para>Specifies a Netlink | |
292 | family to create a socket for to | |
293 | listen on. This expects a short string | |
74d00578 | 294 | referring to the <constant>AF_NETLINK</constant> family |
7a22745a LP |
295 | name (such as <varname>audit</varname> |
296 | or <varname>kobject-uevent</varname>) | |
297 | as argument, optionally suffixed by a | |
298 | whitespace followed by a multicast | |
c5315881 | 299 | group integer. Behavior otherwise is |
7a22745a LP |
300 | very similar to the |
301 | <varname>ListenDatagram=</varname> | |
1f812fea LP |
302 | directive above.</para></listitem> |
303 | </varlistentry> | |
304 | ||
916abb21 LP |
305 | <varlistentry> |
306 | <term><varname>ListenMessageQueue=</varname></term> | |
307 | <listitem><para>Specifies a POSIX | |
308 | message queue name to listen on. This | |
309 | expects a valid message queue name | |
c5315881 | 310 | (i.e. beginning with /). Behavior |
916abb21 LP |
311 | otherwise is very similar to the |
312 | <varname>ListenFIFO=</varname> | |
313 | directive above. On Linux message | |
314 | queue descriptors are actually file | |
315 | descriptors and can be inherited | |
316 | between processes.</para></listitem> | |
317 | </varlistentry> | |
318 | ||
1f812fea LP |
319 | <varlistentry> |
320 | <term><varname>BindIPv6Only=</varname></term> | |
321 | <listitem><para>Takes a one of | |
322 | <option>default</option>, | |
323 | <option>both</option> or | |
324 | <option>ipv6-only</option>. Controls | |
325 | the IPV6_V6ONLY socket option (see | |
326 | <citerefentry><refentrytitle>ipv6</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
327 | for details). If | |
328 | <option>both</option>, IPv6 sockets | |
329 | bound will be accessible via both IPv4 | |
330 | and IPv6. If | |
331 | <option>ipv6-only</option>, they will | |
332 | be accessible via IPv6 only. If | |
333 | <option>default</option> (which is the | |
79640424 | 334 | default, surprise!), the system wide |
1f812fea LP |
335 | default setting is used, as controlled |
336 | by | |
5198dabc LP |
337 | <filename>/proc/sys/net/ipv6/bindv6only</filename>, |
338 | which in turn defaults to the | |
339 | equivalent of | |
340 | <option>both</option>.</para> | |
1f812fea LP |
341 | </listitem> |
342 | </varlistentry> | |
343 | ||
344 | <varlistentry> | |
345 | <term><varname>Backlog=</varname></term> | |
346 | <listitem><para>Takes an unsigned | |
347 | integer argument. Specifies the number | |
348 | of connections to queue that have not | |
349 | been accepted yet. This setting | |
350 | matters only for stream and sequential | |
351 | packet sockets. See | |
352 | <citerefentry><refentrytitle>listen</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
353 | for details. Defaults to SOMAXCONN | |
354 | (128).</para></listitem> | |
355 | </varlistentry> | |
356 | ||
357 | <varlistentry> | |
358 | <term><varname>BindToDevice=</varname></term> | |
359 | <listitem><para>Specifies a network | |
360 | interface name to bind this socket | |
79640424 | 361 | to. If set, traffic will only be |
1f812fea LP |
362 | accepted from the specified network |
363 | interfaces. This controls the | |
364 | SO_BINDTODEVICE socket option (see | |
365 | <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
b439c6ee | 366 | for details). If this option is used, |
1f812fea LP |
367 | an automatic dependency from this |
368 | socket unit on the network interface | |
369 | device unit | |
370 | (<citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
371 | is created.</para></listitem> | |
372 | </varlistentry> | |
373 | ||
374 | <varlistentry> | |
375 | <term><varname>DirectoryMode=</varname></term> | |
376 | <listitem><para>If listening on a file | |
7277f5a9 | 377 | system socket or FIFO, the parent |
1f812fea LP |
378 | directories are automatically created |
379 | if needed. This option specifies the | |
380 | file system access mode used when | |
dd1eb43b LP |
381 | creating these directories. Takes an |
382 | access mode in octal | |
383 | notation. Defaults to | |
384 | 0755.</para></listitem> | |
1f812fea LP |
385 | </varlistentry> |
386 | ||
387 | <varlistentry> | |
388 | <term><varname>SocketMode=</varname></term> | |
389 | <listitem><para>If listening on a file | |
7277f5a9 | 390 | system socket or FIFO, this option |
1f812fea LP |
391 | specifies the file system access mode |
392 | used when creating the file | |
dd1eb43b LP |
393 | node. Takes an access mode in octal |
394 | notation. Defaults to | |
1f812fea LP |
395 | 0666.</para></listitem> |
396 | </varlistentry> | |
397 | ||
398 | <varlistentry> | |
399 | <term><varname>Accept=</varname></term> | |
400 | <listitem><para>Takes a boolean | |
b439c6ee | 401 | argument. If true, a service instance |
1f812fea LP |
402 | is spawned for each incoming |
403 | connection and only the connection | |
b439c6ee | 404 | socket is passed to it. If false, all |
1f812fea LP |
405 | listening sockets themselves are |
406 | passed to the started service unit, | |
407 | and only one service unit is spawned | |
408 | for all connections (also see | |
409 | above). This value is ignored for | |
3c86d34c LP |
410 | datagram sockets and FIFOs where a |
411 | single service unit unconditionally | |
1f812fea LP |
412 | handles all incoming traffic. Defaults |
413 | to <option>false</option>. For | |
b439c6ee | 414 | performance reasons, it is recommended |
1f812fea LP |
415 | to write new daemons only in a way |
416 | that is suitable for | |
3c86d34c | 417 | <option>Accept=false</option>. A |
74d00578 | 418 | daemon listening on an <constant>AF_UNIX</constant> socket |
3c86d34c | 419 | may, but does not need to, call |
77f40f16 | 420 | <citerefentry><refentrytitle>close</refentrytitle><manvolnum>2</manvolnum></citerefentry> |
3c86d34c LP |
421 | on the received socket before |
422 | exiting. However, it must not unlink | |
e9dd9f95 JSJ |
423 | the socket from a file system. It |
424 | should not invoke | |
77f40f16 | 425 | <citerefentry><refentrytitle>shutdown</refentrytitle><manvolnum>2</manvolnum></citerefentry> |
3c86d34c LP |
426 | on sockets it got with |
427 | <varname>Accept=false</varname>, but | |
428 | it may do so for sockets it got with | |
429 | <varname>Accept=true</varname> set. | |
430 | Setting <varname>Accept=true</varname> | |
431 | is mostly useful to allow daemons | |
432 | designed for usage with | |
433 | <citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
b439c6ee | 434 | to work unmodified with systemd socket |
1f812fea LP |
435 | activation.</para></listitem> |
436 | </varlistentry> | |
437 | ||
438 | <varlistentry> | |
439 | <term><varname>MaxConnections=</varname></term> | |
440 | <listitem><para>The maximum number of | |
441 | connections to simultaneously run | |
442 | services instances for, when | |
443 | <option>Accept=true</option> is | |
444 | set. If more concurrent connections | |
b439c6ee | 445 | are coming in, they will be refused |
1f812fea LP |
446 | until at least one existing connection |
447 | is terminated. This setting has no | |
e9dd9f95 | 448 | effect on sockets configured with |
f848f8d8 | 449 | <option>Accept=false</option> or datagram |
1f812fea LP |
450 | sockets. Defaults to |
451 | 64.</para></listitem> | |
452 | </varlistentry> | |
453 | ||
454 | <varlistentry> | |
455 | <term><varname>KeepAlive=</varname></term> | |
456 | <listitem><para>Takes a boolean | |
457 | argument. If true, the TCP/IP stack | |
458 | will send a keep alive message after | |
459 | 2h (depending on the configuration of | |
460 | <filename>/proc/sys/net/ipv4/tcp_keepalive_time</filename>) | |
461 | for all TCP streams accepted on this | |
462 | socket. This controls the SO_KEEPALIVE | |
463 | socket option (see | |
464 | <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
465 | and the <ulink | |
466 | url="http://www.tldp.org/HOWTO/html_single/TCP-Keepalive-HOWTO/">TCP | |
467 | Keepalive HOWTO</ulink> for details.) | |
468 | Defaults to | |
469 | <option>false</option>.</para></listitem> | |
470 | </varlistentry> | |
471 | ||
472 | <varlistentry> | |
473 | <term><varname>Priority=</varname></term> | |
474 | <listitem><para>Takes an integer | |
475 | argument controlling the priority for | |
476 | all traffic sent from this | |
477 | socket. This controls the SO_PRIORITY | |
478 | socket option (see | |
479 | <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
480 | for details.).</para></listitem> | |
481 | </varlistentry> | |
482 | ||
483 | <varlistentry> | |
484 | <term><varname>ReceiveBuffer=</varname></term> | |
485 | <term><varname>SendBuffer=</varname></term> | |
486 | <listitem><para>Takes an integer | |
487 | argument controlling the receive | |
16dad32e AE |
488 | or send buffer sizes of this |
489 | socket, respectively. This controls the SO_RCVBUF | |
490 | and SO_SNDBUF socket options (see | |
1f812fea LP |
491 | <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
492 | for details.).</para></listitem> | |
493 | </varlistentry> | |
494 | ||
495 | <varlistentry> | |
496 | <term><varname>IPTOS=</varname></term> | |
497 | <listitem><para>Takes an integer | |
498 | argument controlling the IP | |
499 | Type-Of-Service field for packets | |
500 | generated from this socket. This | |
501 | controls the IP_TOS socket option (see | |
502 | <citerefentry><refentrytitle>ip</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
503 | for details.). Either a numeric string | |
504 | or one of <option>low-delay</option>, | |
505 | <option>throughput</option>, | |
506 | <option>reliability</option> or | |
507 | <option>low-cost</option> may be | |
508 | specified.</para></listitem> | |
509 | </varlistentry> | |
510 | ||
511 | <varlistentry> | |
512 | <term><varname>IPTTL=</varname></term> | |
513 | <listitem><para>Takes an integer | |
514 | argument controlling the IPv4 | |
515 | Time-To-Live/IPv6 Hop-Count field for | |
516 | packets generated from this | |
517 | socket. This sets the | |
518 | IP_TTL/IPV6_UNICAST_HOPS socket | |
519 | options (see | |
520 | <citerefentry><refentrytitle>ip</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
521 | and | |
522 | <citerefentry><refentrytitle>ipv6</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
523 | for details.)</para></listitem> | |
524 | </varlistentry> | |
525 | ||
526 | <varlistentry> | |
527 | <term><varname>Mark=</varname></term> | |
528 | <listitem><para>Takes an integer | |
529 | value. Controls the firewall mark of | |
530 | packets generated by this socket. This | |
531 | can be used in the firewall logic to | |
532 | filter packets from this socket. This | |
533 | sets the SO_MARK socket option. See | |
534 | <citerefentry><refentrytitle>iptables</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
535 | for details.</para></listitem> | |
536 | </varlistentry> | |
537 | ||
f7db7a69 SL |
538 | <varlistentry> |
539 | <term><varname>ReusePort=</varname></term> | |
540 | <listitem><para>Takes a boolean | |
ac8e20c6 | 541 | value. If true, allows multiple <citerefentry><refentrytitle>bind</refentrytitle><manvolnum>2</manvolnum></citerefentry>s |
f7db7a69 SL |
542 | to this TCP or UDP port. This |
543 | controls the SO_REUSEPORT socket | |
544 | option. See | |
545 | <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
546 | for details.</para></listitem> | |
547 | </varlistentry> | |
548 | ||
0eb59ccf AK |
549 | <varlistentry> |
550 | <term><varname>SmackLabel=</varname></term> | |
551 | <term><varname>SmackLabelIPIn=</varname></term> | |
552 | <term><varname>SmackLabelIPOut=</varname></term> | |
553 | <listitem><para>Takes a string | |
554 | value. Controls the extended | |
555 | attributes | |
556 | <literal>security.SMACK64</literal>, | |
557 | <literal>security.SMACK64IPIN</literal> | |
558 | and | |
559 | <literal>security.SMACK64IPOUT</literal>, | |
560 | respectively, i.e. the security label | |
561 | of the FIFO, or the security label for | |
562 | the incoming or outgoing connections | |
e9dd9f95 | 563 | of the socket, respectively. See |
0eb59ccf AK |
564 | <ulink |
565 | url="https://www.kernel.org/doc/Documentation/security/Smack.txt">Smack.txt</ulink> | |
566 | for details.</para></listitem> | |
567 | </varlistentry> | |
568 | ||
1f812fea LP |
569 | <varlistentry> |
570 | <term><varname>PipeSize=</varname></term> | |
571 | <listitem><para>Takes an integer | |
572 | value. Controls the pipe buffer size | |
573 | of FIFOs configured in this socket | |
e9dd9f95 | 574 | unit. See |
1f812fea LP |
575 | <citerefentry><refentrytitle>fcntl</refentrytitle><manvolnum>2</manvolnum></citerefentry> |
576 | for details.</para></listitem> | |
577 | </varlistentry> | |
578 | ||
916abb21 LP |
579 | <varlistentry> |
580 | <term><varname>MessageQueueMaxMessages=</varname>, | |
581 | <varname>MessageQueueMessageSize=</varname></term> | |
582 | <listitem><para>These two settings | |
583 | take integer values and control the | |
16dad32e | 584 | mq_maxmsg field or the mq_msgsize field, respectively, when |
916abb21 LP |
585 | creating the message queue. Note that |
586 | either none or both of these variables | |
587 | need to be set. See | |
588 | <citerefentry><refentrytitle>mq_setattr</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
589 | for details.</para></listitem> | |
590 | </varlistentry> | |
591 | ||
1f812fea LP |
592 | <varlistentry> |
593 | <term><varname>FreeBind=</varname></term> | |
594 | <listitem><para>Takes a boolean | |
595 | value. Controls whether the socket can | |
596 | be bound to non-local IP | |
597 | addresses. This is useful to configure | |
598 | sockets listening on specific IP | |
599 | addresses before those IP addresses | |
600 | are successfully configured on a | |
601 | network interface. This sets the | |
602 | IP_FREEBIND socket option. For | |
603 | robustness reasons it is recommended | |
604 | to use this option whenever you bind a | |
605 | socket to a specific IP | |
606 | address. Defaults to <option>false</option>.</para></listitem> | |
607 | </varlistentry> | |
608 | ||
6b6d2dee LP |
609 | <varlistentry> |
610 | <term><varname>Transparent=</varname></term> | |
611 | <listitem><para>Takes a boolean | |
612 | value. Controls the IP_TRANSPARENT | |
271b032a | 613 | socket option. Defaults to |
6b6d2dee LP |
614 | <option>false</option>.</para></listitem> |
615 | </varlistentry> | |
616 | ||
ec6370a2 LP |
617 | <varlistentry> |
618 | <term><varname>Broadcast=</varname></term> | |
619 | <listitem><para>Takes a boolean | |
620 | value. This controls the SO_BROADCAST | |
271b032a | 621 | socket option, which allows broadcast |
ec6370a2 LP |
622 | datagrams to be sent from this |
623 | socket. Defaults to | |
624 | <option>false</option>.</para></listitem> | |
625 | </varlistentry> | |
626 | ||
42e87475 | 627 | <varlistentry> |
271b032a | 628 | <term><varname>PassCredentials=</varname></term> |
42e87475 MS |
629 | <listitem><para>Takes a boolean |
630 | value. This controls the SO_PASSCRED | |
74d00578 | 631 | socket option, which allows <constant>AF_UNIX</constant> sockets to |
42e87475 MS |
632 | receive the credentials of the sending |
633 | process in an ancillary message. | |
634 | Defaults to | |
635 | <option>false</option>.</para></listitem> | |
636 | </varlistentry> | |
637 | ||
54ecda32 LP |
638 | <varlistentry> |
639 | <term><varname>PassSecurity=</varname></term> | |
640 | <listitem><para>Takes a boolean | |
641 | value. This controls the SO_PASSSEC | |
74d00578 | 642 | socket option, which allows <constant>AF_UNIX</constant> |
54ecda32 LP |
643 | sockets to receive the security |
644 | context of the sending process in an | |
e9dd9f95 | 645 | ancillary message. Defaults to |
54ecda32 LP |
646 | <option>false</option>.</para></listitem> |
647 | </varlistentry> | |
648 | ||
cebf8b20 TT |
649 | <varlistentry> |
650 | <term><varname>TCPCongestion=</varname></term> | |
651 | <listitem><para>Takes a string | |
652 | value. Controls the TCP congestion | |
653 | algorithm used by this socket. Should | |
654 | be one of "westwood", "veno", "cubic", | |
655 | "lp" or any other available algorithm | |
656 | supported by the IP stack. This | |
657 | setting applies only to stream | |
658 | sockets.</para></listitem> | |
659 | </varlistentry> | |
660 | ||
1f812fea LP |
661 | <varlistentry> |
662 | <term><varname>ExecStartPre=</varname></term> | |
663 | <term><varname>ExecStartPost=</varname></term> | |
b3eaa628 LP |
664 | <listitem><para>Takes one or more |
665 | command lines, which are executed | |
16dad32e | 666 | before or after the listening |
b3eaa628 | 667 | sockets/FIFOs are created and |
16dad32e | 668 | bound, respectively. The first token of the command |
e9dd9f95 | 669 | line must be an absolute filename, |
1f812fea | 670 | then followed by arguments for the |
b3eaa628 LP |
671 | process. Multiple command lines may be |
672 | specified following the same scheme as | |
673 | used for | |
674 | <varname>ExecStartPre=</varname> of | |
675 | service unit files.</para></listitem> | |
1f812fea LP |
676 | </varlistentry> |
677 | ||
678 | <varlistentry> | |
679 | <term><varname>ExecStopPre=</varname></term> | |
680 | <term><varname>ExecStopPost=</varname></term> | |
681 | <listitem><para>Additional commands | |
16dad32e | 682 | that are executed before or after |
1f812fea | 683 | the listening sockets/FIFOs are closed |
16dad32e | 684 | and removed, respectively. Multiple command lines |
b3eaa628 LP |
685 | may be specified following the same |
686 | scheme as used for | |
687 | <varname>ExecStartPre=</varname> of | |
688 | service unit files.</para></listitem> | |
1f812fea LP |
689 | </varlistentry> |
690 | ||
1f812fea LP |
691 | <varlistentry> |
692 | <term><varname>TimeoutSec=</varname></term> | |
693 | <listitem><para>Configures the time to | |
694 | wait for the commands specified in | |
695 | <varname>ExecStartPre=</varname>, | |
696 | <varname>ExecStartPost=</varname>, | |
697 | <varname>ExecStopPre=</varname> and | |
698 | <varname>ExecStopPost=</varname> to | |
b439c6ee KS |
699 | finish. If a command does not exit |
700 | within the configured time, the socket | |
1f812fea | 701 | will be considered failed and be shut |
b439c6ee | 702 | down again. All commands still running, |
1f812fea | 703 | will be terminated forcibly via |
05cc7267 ZJS |
704 | <constant>SIGTERM</constant>, and after another delay of |
705 | this time with <constant>SIGKILL</constant>. (See | |
4819ff03 | 706 | <option>KillMode=</option> in <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>.) |
1f812fea LP |
707 | Takes a unit-less value in seconds, or |
708 | a time span value such as "5min | |
709 | 20s". Pass 0 to disable the timeout | |
63ba209d | 710 | logic. Defaults to <varname>TimeoutStartSec=</varname> from the |
1f19a534 | 711 | manager configuration file.</para></listitem> |
1f812fea LP |
712 | </varlistentry> |
713 | ||
d9ff321a LP |
714 | <varlistentry> |
715 | <term><varname>Service=</varname></term> | |
716 | <listitem><para>Specifies the service | |
717 | unit name to activate on incoming | |
3cf148f3 ZJS |
718 | traffic. This setting is only allowed |
719 | for sockets with | |
720 | <varname>Accept=no</varname>. It | |
721 | defaults to the service that bears the | |
722 | same name as the socket (with the | |
73e231ab | 723 | suffix replaced). In most cases, it |
3cf148f3 ZJS |
724 | should not be necessary to use this |
725 | option.</para></listitem> | |
d9ff321a LP |
726 | </varlistentry> |
727 | ||
1f812fea | 728 | </variablelist> |
4819ff03 LP |
729 | |
730 | <para>Check | |
731 | <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
732 | and | |
733 | <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
734 | for more settings.</para> | |
735 | ||
1f812fea LP |
736 | </refsect1> |
737 | ||
738 | <refsect1> | |
739 | <title>See Also</title> | |
740 | <para> | |
f3e219a2 | 741 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
1f812fea LP |
742 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>, |
743 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
744 | <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
4819ff03 | 745 | <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
3fde5f30 | 746 | <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
9cc2c8b7 ZJS |
747 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
748 | <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
1f812fea | 749 | </para> |
7d617113 ZJS |
750 | |
751 | <para> | |
e9dd9f95 | 752 | For more extensive descriptions see the "systemd for Developers" series: |
7d617113 ZJS |
753 | <ulink url="http://0pointer.de/blog/projects/socket-activation.html">Socket Activation</ulink>, |
754 | <ulink url="http://0pointer.de/blog/projects/socket-activation2.html">Socket Activation, part II</ulink>, | |
755 | <ulink url="http://0pointer.de/blog/projects/inetd.html">Converting inetd Services</ulink>, | |
756 | <ulink url="http://0pointer.de/blog/projects/socket-activated-containers.html">Socket Activated Internet Services and OS Containers</ulink>. | |
757 | </para> | |
1f812fea LP |
758 | </refsect1> |
759 | ||
760 | </refentry> |