man
8 NETWORKMANAGER-DISPATCHER
NETWORKMANAGER-DISPATCHER(Network management daemoNETWORKMANAGER-DISPATCHER(8)
NAME
NetworkManager-dispatcher - Dispatch user scripts for NetworkManager
SYNOPSIS
NetworkManager [OPTIONS...]
DESCRIPTION
NetworkManager-dispatcher service is a D-Bus activated service that
runs user provided scripts upon certain changes in NetworkManager.
NetworkManager-dispatcher will execute scripts in the
/{etc,usr/lib}/NetworkManager/dispatcher.d directory or subdirectories
in alphabetical order in response to network events. Files in /etc take
precedence over identically-named files in /usr/lib. Each script should
be a regular executable file owned by root. Furthermore, it must not be
writable by group or other, and not setuid.
Each script receives two arguments, the first being the interface name
of the device an operation just happened on, and second the action. For
device actions, the interface is the name of the kernel interface
suitable for IP configuration. Thus it is either VPN_IP_IFACE,
DEVICE_IP_IFACE, or DEVICE_IFACE, as applicable. For the hostname
action the device name is always "none". For connectivity-change and
dns-change it is empty.
The actions are:
pre-up
The interface is connected to the network but is not yet fully
activated. Scripts acting on this event must be placed or symlinked
into the /etc/NetworkManager/dispatcher.d/pre-up.d directory, and
NetworkManager will wait for script execution to complete before
indicating to applications that the interface is fully activated.
up
The interface has been activated.
pre-down
The interface will be deactivated but has not yet been disconnected
from the network. Scripts acting on this event must be placed or
symlinked into the /etc/NetworkManager/dispatcher.d/pre-down.d
directory, and NetworkManager will wait for script execution to
complete before disconnecting the interface from its network. Note
that this event is not emitted for forced disconnections, like when
carrier is lost or a wireless signal fades. It is only emitted when
there is an opportunity to cleanly handle a network disconnection
event.
down
The interface has been deactivated.
vpn-pre-up
The VPN is connected to the network but is not yet fully activated.
Scripts acting on this event must be placed or symlinked into the
/etc/NetworkManager/dispatcher.d/pre-up.d directory, and
NetworkManager will wait for script execution to complete before
indicating to applications that the VPN is fully activated.
vpn-up
A VPN connection has been activated.
vpn-pre-down
The VPN will be deactivated but has not yet been disconnected from
the network. Scripts acting on this event must be placed or
symlinked into the /etc/NetworkManager/dispatcher.d/pre-down.d
directory, and NetworkManager will wait for script execution to
complete before disconnecting the VPN from its network. Note that
this event is not emitted for forced disconnections, like when the
VPN terminates unexpectedly or general connectivity is lost. It is
only emitted when there is an opportunity to cleanly handle a VPN
disconnection event.
vpn-down
A VPN connection has been deactivated.
hostname
The system hostname has been updated. Use gethostname(2) to
retrieve it. The interface name (first argument) is empty and no
environment variable is set for this action.
dhcp4-change
The DHCPv4 lease has changed (renewed, rebound, etc).
dhcp6-change
The DHCPv6 lease has changed (renewed, rebound, etc).
connectivity-change
The network connectivity state has changed (no connectivity, went
online, etc).
reapply
The connection was reapplied on the device.
dns-change
The DNS configuration has changed. This action is raised even if
NetworkManager is configured to not manage resolv.conf (for
example, via dns=none). In such case, the dispatch script can
discover the DNS configuration provided by currently active
connections by looking at file /run/NetworkManager/resolv.conf
device-add
This action is called when a connection of type generic has the
generic.device-handler property set. The property indicates the
name of a dispatcher script to be executed in directory
/{etc,usr/lib}/NetworkManager/dispatcher.d/device. Note that
differently from other actions, only one script is executed.
The script needs to perform any action needed to create the device
for the generic connection. On successful termination, the script
returns zero. Otherwise, it returns a non-zero value to indicate an
error. The script can return values to NetworkManager by writing to
standard output; each line should contain a key name followed by
the equal sign '=' and a key value. The keys understood at the
moment are:
IFINDEX
Indicates the interface index of the interface created by the
script. This key is required when the script succeeds; if it is
not set, the activation will fail. The key is ignored in case
of script failure.
ERROR
Specifies an error message indicating the cause of the script
failure. It is ignored when the script succeeds.
Since the dispatcher service captures stdout for parsing those
keys, anything written to stdout will not appear in the dispatcher
service journal log. Use stderr if you want to print messages to
the journal (for example, for debugging). Only the first 8KiB of
stdout are considered and among those, only the first 64 lines; the
rest is ignored.
device-delete
This action is the counterpart of device-add and is called to
delete the device for a generic connection. All the aspects
described for device-add also apply to this action, with the only
exception that key IFINDEX is ignored. It is not necessary to
delete the kernel link in the handler because NetworkManager
already does that; therefore the action is useful for any
additional cleanup needed.
The environment contains more information about the interface and the
connection. The following variables are available for the use in the
dispatcher scripts:
NM_DISPATCHER_ACTION
The dispatcher action like "up" or "dhcp4-change", identical to the
first command line argument. Since NetworkManager 1.12.0.
CONNECTION_UUID
The UUID of the connection profile.
CONNECTION_ID
The name (ID) of the connection profile.
CONNECTION_DBUS_PATH
The NetworkManager D-Bus path of the connection.
CONNECTION_FILENAME
The backing file name of the connection profile (if any).
CONNECTION_EXTERNAL
If "1", this indicates that the connection describes a network
configuration created outside of NetworkManager.
DEVICE_IFACE
The interface name of the control interface of the device.
Depending on the device type, this differs from DEVICE_IP_IFACE.
For example for ADSL devices, this could be 'atm0' or for WWAN
devices it might be 'ttyUSB0'.
DEVICE_IP_IFACE
The IP interface name of the device. This is the network interface
on which IP addresses and routes will be configured.
IP4_ADDRESS_N
The IPv4 address in the format "address/prefix gateway", where N is
a number from 0 to (# IPv4 addresses - 1). gateway item in this
variable is deprecated, use IP4_GATEWAY instead.
IP4_NUM_ADDRESSES
The variable contains the number of IPv4 addresses the script may
expect.
IP4_GATEWAY
The gateway IPv4 address in traditional numbers-and-dots notation.
IP4_ROUTE_N
The IPv4 route in the format "address/prefix next-hop metric",
where N is a number from 0 to (# IPv4 routes - 1).
IP4_NUM_ROUTES
The variable contains the number of IPv4 routes the script may
expect.
IP4_NAMESERVERS
The variable contains a space-separated list of the DNS servers.
IP4_DOMAINS
The variable contains a space-separated list of the search domains.
DHCP4_<dhcp-option-name>
If the connection used DHCP for address configuration, the received
DHCP configuration is passed in the environment using standard DHCP
option names, prefixed with "DHCP4_", like
"DHCP4_HOST_NAME=foobar".
IP6_<name> and DHCP6_<name>
The same variables as for IPv4 are available for IPv6, but the
prefixes are IP6_ and DHCP6_ instead.
CONNECTIVITY_STATE
The network connectivity state, which can take the values defined
by the NMConnectivityState type, from the
org.freedesktop.NetworkManager D-Bus API: UNKNOWN, NONE, PORTAL,
LIMITED or FULL. Note: this variable will only be set for
connectivity-change actions.
In case of VPN, VPN_IP_IFACE is set, and IP4_*, IP6_* variables with
VPN prefix are exported too, like VPN_IP4_ADDRESS_0,
VPN_IP4_NUM_ADDRESSES.
The content of the user setting for the connection being activated is
also passed via environment variables. Each key is stored in a variable
with name CONNECTION_USER_ concatenated with the encoding of the key
name. The encoding works as follows:
o lowercase letters become uppercase
o uppercase letters are prefixed with an underscore
o numbers do not change
o a dot is replaced with a double underscore
o any other character is encoded with an underscore followed by its
3-digit octal representation
For example, key test.foo-Bar2 is stored in a variable named
CONNECTION_USER_TEST__FOO_055_BAR2.
Dispatcher scripts are run one at a time, but asynchronously from the
main NetworkManager process, and will be killed if they run for too
long. If your script might take arbitrarily long to complete, you
should spawn a child process and have the parent return immediately.
Scripts that are symbolic links pointing inside the
/etc/NetworkManager/dispatcher.d/no-wait.d/ directory are run
immediately, without waiting for the termination of previous scripts,
and in parallel. Also beware that once a script is queued, it will
always be run, even if a later event renders it obsolete. (Eg, if an
interface goes up, and then back down again quickly, it is possible
that one or more "up" scripts will be run after the interface has gone
down.)
BUGS
Please report any bugs you find in NetworkManager at the NetworkManager
issue tracker[1].
SEE ALSO
NetworkManager home page[2], NetworkManager(8),
NOTES
1. NetworkManager issue tracker
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/issues
2. NetworkManager home page
https://networkmanager.dev
NetworkManager-dispatcher 1 NETWORKMANAGER-DISPATCHER(8)