Config::Model::models::Systemd::Section::Socket - Configuration class
Systemd::Section::Socket
Configuration classes used by Config::Model
A unit configuration file whose name ends in ".socket" encodes
information about an IPC or network socket or a file system FIFO controlled
and supervised by systemd, for socket-based activation.
This man page lists the configuration options specific to this unit type. See
systemd.unit(5) for the common options of all unit configuration files.
The common configuration items are configured in the generic [Unit] and
[Install] sections. The socket specific configuration options are configured
in the [Socket] section.
Additional options are listed in
systemd.exec(5), which define the
execution environment the "ExecStartPre", "ExecStartPost",
"ExecStopPre" and "ExecStopPost" commands are executed in,
and in
systemd.kill(5), which define the way the processes are
terminated, and in
systemd.resource-control(5), which configure
resource control settings for the processes of the socket.
For each socket unit, a matching service unit must exist, describing the service
to start on incoming traffic on the socket (see
systemd.service(5) for
more information about .service units). The name of the .service unit is by
default the same as the name of the .socket unit, but can be altered with the
"Service" option described below. Depending on the setting of the
"Accept" option described below, this .service unit must either be
named like the .socket unit, but with the suffix replaced, unless overridden
with "Service"; or it must be a template unit named the same way.
Example: a socket file "foo.socket" needs a matching service
"foo.service" if "Accept=no" is set. If
"Accept=yes" is set, a service template "
[email protected]"
must exist from which services are instantiated for each incoming connection.
No implicit "WantedBy" or "RequiredBy" 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 "Requires" dependency may be added.
Socket units may be used to implement on-demand starting of services, as well as
parallelized starting of services. See the blog stories linked at the end for
an introduction.
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
sd_listen_fds(3) for details about the
precise protocol used and the order in which the file descriptors are passed)
or via traditional
inetd(8)-style socket passing (i.e. sockets passed
in via standard input and output, using "StandardInput=socket" in
the service file).
All network sockets allocated through ".socket" units are allocated in
the host's network namespace (see
network_namespaces(7)). This does not
mean however that the service activated by a configured socket unit has to be
part of the host's network namespace as well. It is supported and even good
practice to run services in their own network namespace (for example through
"PrivateNetwork", see
systemd.exec(5)), receiving only the
sockets configured through socket-activation from the host's namespace. In
such a set-up communication within the host's network namespace is only
permitted through the activation sockets passed in while all sockets allocated
from the service code itself will be associated with the service's own
namespace, and thus possibly subject to a restrictive configuration. This
configuration class was generated from systemd documentation. by parse-man.pl
<
https://github.com/dod38fr/config-model-systemd/contrib/parse-man.pl>
Specifies an address to listen on for a stream ("SOCK_STREAM"),
datagram ("SOCK_DGRAM"), or sequential packet
("SOCK_SEQPACKET") socket, respectively. The address can be written
in various formats:
If the address starts with a slash ("/"), it is read as file system
socket in the "AF_UNIX" socket family.
If the address starts with an at symbol ("@"), it is read as abstract
namespace socket in the "AF_UNIX" family. The "@" is
replaced with a "NUL" character before binding. For details, see
unix(7).
If the address string is a single number, it is read as port number to listen on
via IPv6. Depending on the value of "BindIPv6Only" (see below) this
might result in the service being available via both IPv6 and IPv4 (default)
or just via IPv6.
If the address string is a string in the format "v.w.x.y:z", it is
interpreted as IPv4 address v.w.x.y and port z.
If the address string is a string in the format "[x]:y", it is
interpreted as IPv6 address x and port y. An optional interface scope
(interface name or number) may be specified after a "%" symbol:
"[x]:y%dev". Interface scopes are only useful with link-local
addresses, because the kernel ignores them in other cases. Note that if an
address is specified as IPv6, it might still make the service available via
IPv4 too, depending on the "BindIPv6Only" setting (see below).
If the address string is a string in the format "vsock:x:y", it is
read as CID x on a port y address in the "AF_VSOCK" family. The CID
is a unique 32-bit integer identifier in "AF_VSOCK" analogous to an
IP address. Specifying the CID is optional, and may be set to the empty
string.
Note that "SOCK_SEQPACKET" (i.e. "ListenSequentialPacket")
is only available for "AF_UNIX" sockets. "SOCK_STREAM"
(i.e. "ListenStream") when used for IP sockets refers to TCP
sockets, "SOCK_DGRAM" (i.e. "ListenDatagram") to UDP.
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.
It is also possible to have more than one socket unit for the same service when
using "Service", 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.
If an IP address is used here, it is often desirable to listen on it 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 "FreeBind" option described below.
Optional. Type list of uniline.
Specifies an address to listen on for a stream ("SOCK_STREAM"),
datagram ("SOCK_DGRAM"), or sequential packet
("SOCK_SEQPACKET") socket, respectively. The address can be written
in various formats:
If the address starts with a slash ("/"), it is read as file system
socket in the "AF_UNIX" socket family.
If the address starts with an at symbol ("@"), it is read as abstract
namespace socket in the "AF_UNIX" family. The "@" is
replaced with a "NUL" character before binding. For details, see
unix(7).
If the address string is a single number, it is read as port number to listen on
via IPv6. Depending on the value of "BindIPv6Only" (see below) this
might result in the service being available via both IPv6 and IPv4 (default)
or just via IPv6.
If the address string is a string in the format "v.w.x.y:z", it is
interpreted as IPv4 address v.w.x.y and port z.
If the address string is a string in the format "[x]:y", it is
interpreted as IPv6 address x and port y. An optional interface scope
(interface name or number) may be specified after a "%" symbol:
"[x]:y%dev". Interface scopes are only useful with link-local
addresses, because the kernel ignores them in other cases. Note that if an
address is specified as IPv6, it might still make the service available via
IPv4 too, depending on the "BindIPv6Only" setting (see below).
If the address string is a string in the format "vsock:x:y", it is
read as CID x on a port y address in the "AF_VSOCK" family. The CID
is a unique 32-bit integer identifier in "AF_VSOCK" analogous to an
IP address. Specifying the CID is optional, and may be set to the empty
string.
Note that "SOCK_SEQPACKET" (i.e. "ListenSequentialPacket")
is only available for "AF_UNIX" sockets. "SOCK_STREAM"
(i.e. "ListenStream") when used for IP sockets refers to TCP
sockets, "SOCK_DGRAM" (i.e. "ListenDatagram") to UDP.
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.
It is also possible to have more than one socket unit for the same service when
using "Service", 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.
If an IP address is used here, it is often desirable to listen on it 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 "FreeBind" option described below.
Optional. Type list of uniline.
Specifies an address to listen on for a stream ("SOCK_STREAM"),
datagram ("SOCK_DGRAM"), or sequential packet
("SOCK_SEQPACKET") socket, respectively. The address can be written
in various formats:
If the address starts with a slash ("/"), it is read as file system
socket in the "AF_UNIX" socket family.
If the address starts with an at symbol ("@"), it is read as abstract
namespace socket in the "AF_UNIX" family. The "@" is
replaced with a "NUL" character before binding. For details, see
unix(7).
If the address string is a single number, it is read as port number to listen on
via IPv6. Depending on the value of "BindIPv6Only" (see below) this
might result in the service being available via both IPv6 and IPv4 (default)
or just via IPv6.
If the address string is a string in the format "v.w.x.y:z", it is
interpreted as IPv4 address v.w.x.y and port z.
If the address string is a string in the format "[x]:y", it is
interpreted as IPv6 address x and port y. An optional interface scope
(interface name or number) may be specified after a "%" symbol:
"[x]:y%dev". Interface scopes are only useful with link-local
addresses, because the kernel ignores them in other cases. Note that if an
address is specified as IPv6, it might still make the service available via
IPv4 too, depending on the "BindIPv6Only" setting (see below).
If the address string is a string in the format "vsock:x:y", it is
read as CID x on a port y address in the "AF_VSOCK" family. The CID
is a unique 32-bit integer identifier in "AF_VSOCK" analogous to an
IP address. Specifying the CID is optional, and may be set to the empty
string.
Note that "SOCK_SEQPACKET" (i.e. "ListenSequentialPacket")
is only available for "AF_UNIX" sockets. "SOCK_STREAM"
(i.e. "ListenStream") when used for IP sockets refers to TCP
sockets, "SOCK_DGRAM" (i.e. "ListenDatagram") to UDP.
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.
It is also possible to have more than one socket unit for the same service when
using "Service", 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.
If an IP address is used here, it is often desirable to listen on it 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 "FreeBind" option described below.
Optional. Type list of uniline.
Specifies a file system FIFO (see
fifo(7) for details) to listen on. This
expects an absolute file system path as argument. Behavior otherwise is very
similar to the "ListenDatagram" directive above.
Optional. Type
list of uniline.
Specifies a special file in the file system to listen on. This expects an
absolute file system path as argument. Behavior otherwise is very similar to
the "ListenFIFO" directive above. Use this to open character device
nodes as well as special files in "/proc/" and "/sys/".
Optional. Type list of uniline.
Specifies a Netlink family to create a socket for to listen on. This expects a
short string referring to the "AF_NETLINK" family name (such as
"audit" or "kobject-uevent") as argument, optionally
suffixed by a whitespace followed by a multicast group integer. Behavior
otherwise is very similar to the "ListenDatagram" directive above.
Optional. Type list of uniline.
Specifies a POSIX message queue name to listen on (see
mq_overview(7) for
details). This expects a valid message queue name (i.e. beginning with
"/"). Behavior otherwise is very similar to the
"ListenFIFO" directive above. On Linux message queue descriptors are
actually file descriptors and can be inherited between processes.
Optional. Type list of uniline.
Specifies a USB FunctionFS <
https://docs.kernel.org/usb/functionfs.html>
endpoints location to listen on, for implementation of USB gadget functions.
This expects an absolute file system path of a FunctionFS mount point as the
argument. Behavior otherwise is very similar to the "ListenFIFO"
directive above. Use this to open the FunctionFS endpoint "ep0".
When using this option, the activated service has to have the
"USBFunctionDescriptors" and "USBFunctionStrings" options
set.
Optional. Type list of uniline.
Takes one of "udplite" or "sctp". The socket will use the
UDP-Lite ("IPPROTO_UDPLITE") or SCTP ("IPPROTO_SCTP")
protocol, respectively.
Optional. Type enum. choice: 'udplite', 'sctp'.
Takes one of "default", "both" or "ipv6-only".
Controls the IPV6_V6ONLY socket option (see
ipv6(7) for details). If
"both", IPv6 sockets bound will be accessible via both IPv4 and
IPv6. If "ipv6-only", they will be accessible via IPv6 only. If
"default" (which is the default, surprise!), the system wide default
setting is used, as controlled by "/proc/sys/net/ipv6/bindv6only",
which in turn defaults to the equivalent of "both".
Optional.
Type enum. choice: 'default', 'both', 'ipv6-only'.
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
listen(2) for details. Defaults to
SOMAXCONN (128).
Optional. Type uniline.
Specifies a network interface name to bind this socket to. If set, traffic will
only be accepted from the specified network interfaces. This controls the
"SO_BINDTODEVICE" socket option (see
socket(7) for details).
If this option is used, an implicit dependency from this socket unit on the
network interface device unit is created (see
systemd.device(5)). Note
that setting this parameter might result in additional dependencies to be
added to the unit (see above).
Optional. Type uniline.
Takes a UNIX user/group name. When specified, all "AF_UNIX" sockets
and FIFO nodes in the file system are owned by the specified user and group.
If unset (the default), the nodes are owned by the root user/group (if run in
system context) or the invoking user/group (if run in user context). If only a
user is specified but no group, then the group is derived from the user's
default group.
Optional. Type uniline.
Takes a UNIX user/group name. When specified, all "AF_UNIX" sockets
and FIFO nodes in the file system are owned by the specified user and group.
If unset (the default), the nodes are owned by the root user/group (if run in
system context) or the invoking user/group (if run in user context). If only a
user is specified but no group, then the group is derived from the user's
default group.
Optional. Type uniline.
If listening on a file system socket or FIFO, this option specifies the file
system access mode used when creating the file node. Takes an access mode in
octal notation. Defaults to 0666.
Optional. Type uniline.
If listening on a file system socket or FIFO, the parent 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.
Optional. Type uniline.
Takes a boolean argument. If yes, a service instance is spawned for each
incoming connection and only the connection socket is passed to it. If no, all
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 handles all incoming traffic. Defaults to "no". For
performance reasons, it is recommended to write new daemons only in a way that
is suitable for "Accept=no". A daemon listening on an
"AF_UNIX" socket may, but does not need to, call
close(2) on
the received socket before exiting. However, it must not unlink the socket
from a file system. It should not invoke
shutdown(2) on sockets it got
with "Accept=no", but it may do so for sockets it got with
"Accept=yes" set. Setting "Accept=yes" is mostly useful to
allow daemons designed for usage with
inetd(8) to work unmodified with
systemd socket activation.
For IPv4 and IPv6 connections, the "REMOTE_ADDR" environment variable
will contain the remote IP address, and "REMOTE_PORT" will contain
the remote port. This is the same as the format used by CGI. For
"SOCK_RAW", the port is the IP protocol.
It is recommended to set "CollectMode=inactive-or-failed" for service
instances activated via "Accept=yes", to ensure that failed
connection services are cleaned up and released from memory, and do not
accumulate.
Optional. Type boolean.
Takes a boolean argument. May only be used in conjunction with
"ListenSpecial". If true, the specified special file is opened in
read-write mode, if false, in read-only mode. Defaults to false.
Optional.
Type boolean.
Takes a boolean argument. May only be used when "Accept=no". If yes,
the socket's buffers are cleared after the triggered service exited. This
causes any pending data to be flushed and any pending incoming connections to
be rejected. If no, the socket's buffers won't be cleared, permitting the
service to handle any pending connections after restart, which is the usually
expected behaviour. Defaults to "no".
Optional. Type boolean.
The maximum number of connections to simultaneously run services instances for,
when "Accept=yes" is set. If more concurrent connections are coming
in, they will be refused until at least one existing connection is terminated.
This setting has no effect on sockets configured with "Accept=no" or
datagram sockets. Defaults to 64.
Optional. Type uniline.
The maximum number of connections for a service per source IP address. This is
very similar to the "MaxConnections" directive above. Disabled by
default.
Optional. Type uniline.
Takes a boolean argument. If true, the TCP/IP stack will send a keep alive
message after 2h (depending on the configuration of
"/proc/sys/net/ipv4/tcp_keepalive_time") for all TCP streams
accepted on this socket. This controls the "SO_KEEPALIVE" socket
option (see
socket(7) and the TCP Keepalive HOWTO
<
http://www.tldp.org/HOWTO/html_single/TCP-Keepalive-HOWTO/> for
details.) Defaults to "false".
Optional. Type boolean.
Takes time (in seconds) as argument. The connection needs to remain idle before
TCP starts sending keepalive probes. This controls the TCP_KEEPIDLE socket
option (see
socket(7) and the TCP Keepalive HOWTO
<
http://www.tldp.org/HOWTO/html_single/TCP-Keepalive-HOWTO/> for
details.) Defaults value is 7200 seconds (2 hours).
Optional. Type
integer.
Takes time (in seconds) as argument between individual keepalive probes, if the
socket option "SO_KEEPALIVE" has been set on this socket. This
controls the "TCP_KEEPINTVL" socket option (see
socket(7) and
the TCP Keepalive HOWTO
<
http://www.tldp.org/HOWTO/html_single/TCP-Keepalive-HOWTO/> for
details.) Defaults value is 75 seconds.
Optional. Type integer.
Takes an integer as argument. It is the number of unacknowledged probes to send
before considering the connection dead and notifying the application layer.
This controls the TCP_KEEPCNT socket option (see
socket(7) and the TCP
Keepalive HOWTO
<
http://www.tldp.org/HOWTO/html_single/TCP-Keepalive-HOWTO/> for
details.) Defaults value is 9.
Optional. Type integer.
Takes a boolean argument. TCP Nagle's algorithm works by combining a number of
small outgoing messages, and sending them all at once. This controls the
TCP_NODELAY socket option (see
tcp(7)). Defaults to "false".
Optional. Type boolean.
Takes an integer argument controlling the priority for all traffic sent from
this socket. This controls the "SO_PRIORITY" socket option (see
socket(7) for details.).
Optional. Type integer.
Takes time (in seconds) as argument. If set, the listening process will be
awakened only when data arrives on the socket, and not immediately when
connection is established. When this option is set, the
"TCP_DEFER_ACCEPT" socket option will be used (see
tcp(7)),
and the kernel will ignore initial ACK packets without any data. The argument
specifies the approximate amount of time the kernel should wait for incoming
data before falling back to the normal behavior of honoring empty ACK packets.
This option is beneficial for protocols where the client sends the data first
(e.g. HTTP, in contrast to SMTP), because the server process will not be woken
up unnecessarily before it can take any action.
If the client also uses the "TCP_DEFER_ACCEPT" option, the latency of
the initial connection may be reduced, because the kernel will send data in
the final packet establishing the connection (the third packet in the
"three-way handshake").
Disabled by default.
Optional. Type integer.
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
socket(7) for details.). The
usual suffixes K, M, G are supported and are understood to the base of 1024.
Optional. Type uniline.
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
socket(7) for details.). The
usual suffixes K, M, G are supported and are understood to the base of 1024.
Optional. Type uniline.
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
ip(7) for details.). Either a numeric string or one of
"low-delay", "throughput", "reliability" or
"low-cost" may be specified.
Optional. Type integer.
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
ip(7) and
ipv6(7) for details.)
Optional. Type integer.
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
iptables(8) for details.
Optional. Type integer.
Takes a boolean value. If true, allows multiple
bind(2)s to this TCP or
UDP port. This controls the "SO_REUSEPORT" socket option. See
socket(7) for details.
Optional. Type boolean.
Takes a string value. Controls the extended attributes
"security.SMACK64", "security.SMACK64IPIN" and
"security.SMACK64IPOUT", respectively, i.e. the security label of
the FIFO, or the security label for the incoming or outgoing connections of
the socket, respectively. See Smack
<
https://docs.kernel.org/admin-guide/LSM/Smack.html> for details.
Optional. Type uniline.
Takes a string value. Controls the extended attributes
"security.SMACK64", "security.SMACK64IPIN" and
"security.SMACK64IPOUT", respectively, i.e. the security label of
the FIFO, or the security label for the incoming or outgoing connections of
the socket, respectively. See Smack
<
https://docs.kernel.org/admin-guide/LSM/Smack.html> for details.
Optional. Type uniline.
Takes a string value. Controls the extended attributes
"security.SMACK64", "security.SMACK64IPIN" and
"security.SMACK64IPOUT", respectively, i.e. the security label of
the FIFO, or the security label for the incoming or outgoing connections of
the socket, respectively. See Smack
<
https://docs.kernel.org/admin-guide/LSM/Smack.html> for details.
Optional. Type uniline.
Takes a boolean argument. When true, systemd will attempt to figure out the
SELinux label used for the instantiated service from the information handed by
the peer over the network. Note that only the security level is used from the
information provided by the peer. Other parts of the resulting SELinux context
originate from either the target binary that is effectively triggered by
socket unit or from the value of the "SELinuxContext" option. This
configuration option applies only when activated service is passed in single
socket file descriptor, i.e. service instances that have standard input
connected to a socket or services triggered by exactly one socket unit. Also
note that this option is useful only when MLS/MCS SELinux policy is deployed.
Defaults to "false".
Optional. Type boolean.
Takes a size in bytes. Controls the pipe buffer size of FIFOs configured in this
socket unit. See
fcntl(2) for details. The usual suffixes K, M, G are
supported and are understood to the base of 1024.
Optional. Type uniline.
These two settings take integer values and control the mq_maxmsg field or the
mq_msgsize field, respectively, when creating the message queue. Note that
either none or both of these variables need to be set. See
mq_setattr(3) for details.
Optional. Type uniline.
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"/"IPV6_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
"false".
Optional. Type boolean.
Takes a boolean value. Controls the
"IP_TRANSPARENT"/"IPV6_TRANSPARENT" socket option.
Defaults to "false".
Optional. Type boolean.
Takes a boolean value. This controls the "SO_BROADCAST" socket option,
which allows broadcast datagrams to be sent from this socket. Defaults to
"false".
Optional. Type boolean.
Takes a boolean value. This controls the "SO_PASSCRED" socket option,
which allows "AF_UNIX" sockets to receive the credentials of the
sending process in an ancillary message. Defaults to "false".
Optional. Type boolean.
Takes a boolean value. This controls the "SO_PASSSEC" socket option,
which allows "AF_UNIX" sockets to receive the security context of
the sending process in an ancillary message. Defaults to "false".
Optional. Type boolean.
Takes a boolean value. This controls the "IP_PKTINFO",
"IPV6_RECVPKTINFO", "NETLINK_PKTINFO" or
"PACKET_AUXDATA" socket options, which enable reception of
additional per-packet metadata as ancillary message, on "AF_INET",
"AF_INET6", "AF_UNIX" and "AF_PACKET" sockets.
Defaults to "false".
Optional. Type boolean.
Takes one of "off", "us" (alias: "usec",
"Xs") or "ns" (alias: "nsec"). This controls the
"SO_TIMESTAMP" or "SO_TIMESTAMPNS" socket options, and
enables whether ingress network traffic shall carry timestamping metadata.
Defaults to "off".
Optional. Type enum. choice: 'off', 'us',
'usec', 'Xs', 'ns', 'nsec'.
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.
Optional. Type uniline.
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, then followed by arguments
for the process. Multiple command lines may be specified following the same
scheme as used for "ExecStartPre" of service unit files.
Optional. Type list of uniline.
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, then followed by arguments
for the process. Multiple command lines may be specified following the same
scheme as used for "ExecStartPre" of service unit files.
Optional. Type list of uniline.
Additional commands that are executed before or after the listening
sockets/FIFOs are closed and removed, respectively. Multiple command lines may
be specified following the same scheme as used for "ExecStartPre" of
service unit files.
Optional. Type list of uniline.
Additional commands that are executed before or after the listening
sockets/FIFOs are closed and removed, respectively. Multiple command lines may
be specified following the same scheme as used for "ExecStartPre" of
service unit files.
Optional. Type list of uniline.
Configures the time to wait for the commands specified in
"ExecStartPre", "ExecStartPost", "ExecStopPre"
and "ExecStopPost" to finish. If a command does not exit within the
configured time, the socket will be considered failed and be shut down again.
All commands still running will be terminated forcibly via
"SIGTERM", and after another delay of this time with
"SIGKILL". (See "KillMode" in
systemd.kill(5).)
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
"DefaultTimeoutStartSec" from the manager configuration file (see
systemd-system.conf(5)).
Optional. Type uniline.
Specifies the service unit name to activate on incoming traffic. This setting is
only allowed for sockets with "Accept=no". 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. Note that setting
this parameter might result in additional dependencies to be added to the unit
(see above).
Optional. Type uniline.
Takes a boolean argument. If enabled, any file nodes created by this socket unit
are removed when it is stopped. This applies to "AF_UNIX" sockets in
the file system, POSIX message queues, FIFOs, as well as any symlinks to them
configured with "Symlinks". Normally, it should not be necessary to
use this option, and is not recommended as services might continue to run
after the socket unit has been terminated and it should still be possible to
communicate with them via their file system node. Defaults to off.
Optional. Type boolean.
Takes a list of file system paths. The specified paths will be created as
symlinks to the "AF_UNIX" socket path or FIFO path of this socket
unit. If this setting is used, only one "AF_UNIX" socket in the file
system or one FIFO may be configured for the socket unit. Use this option to
manage one or more symlinked alias names for a socket, binding their lifecycle
together. Note that if creation of a symlink fails this is not considered
fatal for the socket unit, and the socket unit may still start. If an empty
string is assigned, the list of paths is reset. Defaults to an empty list.
Optional. Type uniline.
Assigns a name to all file descriptors this socket unit encapsulates. This is
useful to help activated services identify specific file descriptors, if
multiple fds are passed. Services may use the
sd_listen_fds_with_names(3) call to acquire the names configured for
the received file descriptors. Names may contain any ASCII character, but must
exclude control characters and ":", and must be at most 255
characters in length. If this setting is not used, the file descriptor name
defaults to the name of the socket unit, including its ".socket"
suffix.
Optional. Type uniline.
Configures a limit on how often this socket unit may be activated within a
specific time interval. The "TriggerLimitIntervalSec" may be used to
configure the length of the time interval in the usual time units
"us", "ms", "s", "min", "h",
X and defaults to 2s (See
systemd.time(7) for details on the various
time units understood). The "TriggerLimitBurst" setting takes a
positive integer value and specifies the number of permitted activations per
time interval, and defaults to 200 for "Accept=yes" sockets (thus by
default permitting 200 activations per 2s), and 20 otherwise (20 activations
per 2s). Set either to 0 to disable any form of trigger rate limiting. If the
limit is hit, the socket unit is placed into a failure mode, and will not be
connectible anymore until restarted. Note that this limit is enforced before
the service activation is enqueued.
Optional. Type uniline.
Configures a limit on how often this socket unit may be activated within a
specific time interval. The "TriggerLimitIntervalSec" may be used to
configure the length of the time interval in the usual time units
"us", "ms", "s", "min", "h",
X and defaults to 2s (See
systemd.time(7) for details on the various
time units understood). The "TriggerLimitBurst" setting takes a
positive integer value and specifies the number of permitted activations per
time interval, and defaults to 200 for "Accept=yes" sockets (thus by
default permitting 200 activations per 2s), and 20 otherwise (20 activations
per 2s). Set either to 0 to disable any form of trigger rate limiting. If the
limit is hit, the socket unit is placed into a failure mode, and will not be
connectible anymore until restarted. Note that this limit is enforced before
the service activation is enqueued.
Optional. Type uniline.
- •
- cme
- 2010-2016 Lennart Poettering and others
- 2016 Dominique Dumont
- LGPLv2.1+