bionic (8) netplugd.8.gz

NAME

     netplugd — network cable hotplug management daemon

SYNOPSIS

     netplugd [-FP] [-c config_file] [-s script_file] [-i interface_pattern] [-p pid_file]

DESCRIPTION

     netplugd is a daemon that responds to network link events from the Linux kernel, such as a network
     interface losing or acquiring a carrier signal.

     When an Ethernet-style network interface on a host is plugged into a powered-up switch, hub, or other host,
     the two use a carrier signal to establish that the link is alive.  The Linux kernel makes this information
     available through its netlink(7) interface.

     The netplugd daemon listens for carrier detection and loss messages from the kernel's netlink(7) subsystem.
     When a carrier signal is detected on an interface, it runs a script to bring the interface up.  When
     carrier is lost, netplugd runs a script to bring the interface down.  netplugd does not define any policies
     for how to manage interfaces; it leaves that to a script, /etc/netplug.d/netplug, which is described in
     FILES below.

     You tell netplugd which interfaces it should manage by giving it a list of shell-style glob patterns, which
     it matches against using the fnmatch(3) function.  For example, a pattern of eth[13] will tell netplugd to
     only manage eth1 and eth3, if those interfaces exist.  If the interfaces are not known to the kernel at the
     time you start netplugd, perhaps because they are unplugged PCMCIA network interfaces or devices whose
     drivers have not yet been installed, netplugd will start to manage them as soon as they are plugged in or
     their drivers are available.

OPTIONS

     -F      Run in the foreground; do not detach and run as a daemon.  Messages are logged to stdout or stderr,
             instead of using the syslog(3) mechanism.  This option is useful mainly for debugging your
             configuration.

     -P      Prevent autoprobing for interfaces.  The netplugd daemon normally probes for all possible interface
             names that might match the patterns you tell it to manage.  This is necessary in order to get
             network driver modules (the default with almost all Linux distributions) loaded and set up, so that
             they can provide link status notifications to the netplugd daemon.  Autoprobing should always be
             safe, and doesn't take long.  Disable it with caution.

     -c config_file
             Specify the name of a file from which to read patterns that describe the interfaces to manage.  You
             can provide this option multiple times to read from more than one file.  If you do not provide this
             option at all, netplugd will attempt to read from a default config file.  If you do not want
             netplugd to try to read from any real config files, you can specify /dev/null as a config file.

     -s script_file
             Specify an alternative script file path, override /etc/netplug.d/netplug

     -i interface_pattern
             Specify a pattern that will be used to match interface names that netplugd should manage.  You can
             provide this option multiple times to specify multiple patterns.

     -p pid_file
             Write the daemon's process ID to the file pid_file.  If you tell netplugd to run in the foreground,
             this option is ignored.

FILES

     /etc/netplug/netplugd.conf
             Default config file to read, if none is specified on the command line.  The config file format is
             one pattern per line, with white space, empty lines, and comments starting with a # character
             ignored.  Patterns are standard shell-style glob patterns, e.g. "eth[0-9]".

     /etc/netplug.d/netplug
             The "policy" program (typically a shell script) that netplugd uses to probe for interfaces, and to
             bring them up or down in response to network link events.  This program is called with the name of
             the interface as its first argument, and one of the following options:

             in      A cable was plugged in, or carrier came up.  The command should bring the interface up.
                     The command is run asynchronously, and it should exit with status 0 on success.

             out     A cable was plugged out, or carrier went down.  The command should bring the interface
                     down.  The command is run asynchronously, and it should exit with status 0 on success.

             probe   The command should load and initialise the driver for this interface, if possible, and
                     bring the interface into the "up" state, so that it can generate netlink(7) events.  The
                     command is run synchronously; it must exit with status code 0 if it succeeds, otherwise
                     with a non-zero exit code or signal.

     /etc/init.d/netplug
             The init(8) script that starts, stops, and displays status of the netplugd daemon.

AUTHOR

     netplugd was written by Bryan O'Sullivan <bos@serpentine.com>.

COPYRIGHT AND LICENSE

     Copyright 2003 PathScale, Inc.  Copyright 2003, 2004, 2005 Bryan O'Sullivan

     netplugd is free software; you can redistribute it and/or modify it under the terms of the GNU General
     Public License, version 2, as published by the Free Software Foundation.  You are forbidden from
     redistributing or modifying it under the terms of any other license, including other versions of the GNU
     General Public License.

     netplugd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the
     implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
     License for more details.

SEE ALSO

     cardmgr(5), hotplug(8), ip(8), netlink(7)