ifplugd 实现网口检测

转自http://linux.die.net/man/8/ifplugd

Name

ifplugd - A link detection daemon for ethernet devices

Synopsis

ifplugd [options]

Description

ifplugd is a daemon which will automatically configure your ethernet device when a cable is plugged in and automatically unconfigure it if the cable is pulled. This is useful on laptops with on-board network adapters, since it will only configure the interface when a cable is really connected.

It uses your distribution's native ifup/ifdown programs, but can be configured to do anything you wish when the state of the interface changes. It may ignore short unplugged whiles (-d option) or plugged whiles (-u option).

ifplugd may be used in "compatibility mode" by specifying -F on the command line. Than ifplugd will treat network drivers which do not support link beat querying as always online.

Options

-a | --no-auto

Do not enable interface automatically (default: off)

-n | --no-daemon

Do not daemonize (for debugging) (default: off)

-s | --no-syslog

Do not use syslog, use stdout instead (for debugging) (default: off).

-b | --no-beep

Do not beep (off)

-f | --ignore-fail

Ignore detection failure, retry instead. Failure is treated as "no link". (default: off)

-F | --ignore-fail-positive

Ignore detection failure, retry instead. Failure is treated as "link detected". (default: off)

-i | --iface= IFACE

Specify ethernet interface (default: eth0)

-r | --run= EXEC

Specify program to execute when link status changes (default: /etc/ifplugd/ifplugd.action)

-I | --ignore-retval

Don't exit on nonzero return value of program executed on link change. (default: off)

-t | --poll-time= SECS

Specify poll time in seconds (default: 1)

-u | --delay-up= SECS

Specify delay for configuring interface (default: 0)

-d | --delay-down= SECS

Specify delay for deconfiguring interface (default: 5)

-m | --api-mode= MODE

Force a specific link beat detection ioctl() API. Possible values are auto, iff, wlan, ethtool, mii, and priv for automatic detection, interface flag (IFF_RUNNING), wireless extension, SIOCETHTOOL, SIOCGMIIREG resp. SIOCPRIV. Only the first character of the argument is relevant, case insensitive. (default: auto)

-p | --no-startup

Don't call the script to bring up network on deamon start (default: off)

-q | --no-shutdown

Don't call the script for network shutdown on deamon quit (default: off)

-w | --wait-on-fork

When daemonizing, wait until the background process finished with the initial link beat detection. When this is enabled, the parent process will return the link status on exit. 1 means link beat detected, 2 stands for link beat not detected, everything else is an error.

-W | --wait-on-kill

When killing a running daemon (with -k) wait until the daemon died.

-x | --extra-arg= ARG

Specify an extra argument to be passed to the action script.

-M | --monitor

Don't fail when the network interface is not available, instead use NETLINK to monitor device avaibility. The is useful for PCMCIA devices and similar.

-h | --help

Show help

-k | --kill

Kill a running daemon (Specify -i to select the daemon instance to kill)

-c | --check-running

Check if a daemon is running for a given network interface. Sets the return value to 0 if a daemon is already running or to 255 if not.

-v | --version

Show version

-S | --supend

Suspend a running daemon. The daemon will no longer check the link status until it is resumed (-R) again. (Specify -i to select the daemon instance to suspend.)

-R | --resume

Resume a suspended daemon. (Specify -i to select the daemon instance to resume.)

-z | --info

Request that a running daemon shall write its status information to syslog. (Specify -i to select the daemon instance to send the request to.)

Files

/etc/ifplugd/ifplugd.conf: this file is sourced by the init script /etc/init.d/ifplugd and contains the interface to be monitored and the options to be used.

/etc/ifplugd/ifplugd.action: this is the script which will be called by the daemon whenever the state of the interface changes. It takes two areguments: the first is the interface name (eg. eth0), the second either "up" or "down".

/var/run/ifplugd.<iface>.pid: the pid file for ifplugd.

Environment

The action script will be called with two environment variables set:

IFPLUGD_PREVIOUS The previous link status. Either "up", "down", "error" or "disabled". The former values should be obvious, the latter is set on daemon startup.

IFPLUGD_CURRENT The current link status. See above for possible values.

Signals

SIGINT, SIGTERM ifplugd will quit, possibly running the shutdown script. This is issued by passing -k to ifplugd.

SIGQUIT ifplugd will quit, the shutdown script is never run.

SIGHUP ifplugd will write its status information to syslog. This is issued by -z.

SIGUSR1 ifplugd will go to suspend mode. (-S)

SIGUSR2 ifplugd will resume from suspend mode. (-R)

Author

ifplugd was written by Lennart Poettering <mzvscyhtq (at) 0pointer (dot) de>. ifplugd is available at http://0pointer.de/lennart/projects/ifplugd/

See Also

ifplugd.conf(5), ifup(8), interfaces(5), ifconfig(8), ifplugstatus(8)

Comments

This man page was written using xmltoman(1) by Oliver Kurth.

Referenced By

waproamd(8)

转自http://blog.chinaunix.net/uid-9672747-id-3278700.html

ifplugd检测eth0拔插消息 (2012-07-18 15:21) 一键转载

分类： Linux常用知识

 

为了检测固定网线口的拔插消息，在busybox里配置了ifplugd

 

ptions:
        -n              Don't daemonize
        -s              Don't log to syslog
        -i IFACE        Interface
        -f/-F           Treat link detection error as link down/link up
                        (otherwise exit on error)
        -a              Don't up interface at each link probe
        -M              Monitor creation/destruction of interface
                        (otherwise it must exist)
        -r PROG         Script to run
        -x ARG          Extra argument for script
        -I              Don't exit on nonzero exit code from script
        -p              Don't run script on daemon startup
        -q              Don't run script on daemon quit
        -l              Run script on startup even if no cable is detected
        -t SECS         Poll time in seconds
        -u SECS         Delay before running script after link up
        -d SECS         Delay after link down
        -m MODE         API mode (mii, priv, ethtool, wlan, iff, auto)
        -k              Kill running daemon

 

系统起来后运行ifplugd -nI -i eth0 -r /etc/network/if.sh会在当前shell启动ifplugd并检测网口状态

# ifplugd -nI -i eth0 -r /etc/network/if.sh
ifplugd(eth0): started: BusyBox v1.16.1 (2011-01-28 11:42:48 HKT)
ifplugd(eth0): using SIOCETHTOOL detection mode
ifplugd(eth0): link is up
ifplugd(eth0): executing '/etc/network/if.sh eth0 up'
ifplugd(eth0): exit code: 0
GMAC:eth0: Link is down
ifplugd(eth0): link is down
ifplugd(eth0): executing '/etc/network/if.sh eth0 down'
ifplugd(eth0): exit code: 0
GMAC:eth0 : Link is Up
ifplugd(eth0): link is up
ifplugd(eth0): executing '/etc/network/if.sh eth0 up'
ifplugd(eth0): exit code: 0

 

基于上面的资料我做了个简单的网口检测程序

从上面的红色字体可以看出当ifplugd指令执行的时候会调用后面的指定的脚本，并且向脚本中传递参数

在文件系统中装上ifplugd后，启动ifplugd作为守护进程在后台执行，同时指定网口改变时执行的脚本文件，当网口和断开分别执行不同的程序，

 

脚本：

#!/bin/sh
echo "if1.sh"
echo $#
echo $0
echo $1
echo $2
if [ $# -eq 2 ];then
   if [ $1 = "eth0" ];then
   echo -n "ech0  "
   fi
   if [ $2 = "up" ];then
   echo "up"
   exec /etc/network/net_up
   elif [ $2 = "down" ];then
   echo "down"
   exec /etc/network/net_down
   elif [ $2 = "disable" ];then
   echo "disable"
   elif [ $2 = "error" ];then
   echo "error"
   fi
fi