네트워크 케이블 / 커넥터의 물리적 연결 상태를 감지하는 방법은 무엇입니까?

네트워크 케이블 / 커넥터의 물리적 연결 상태를 감지하는 방법은 무엇입니까?

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Linux 환경에서 RJ45 커넥터의 물리적 연결 또는 연결 해제 상태를 소켓에 감지해야합니다. BASH 스크립팅 만 사용하는 것이 좋습니다.

다른 사이트에서 제안 된 다음 솔루션은이 목적으로 작동하지 않습니다.

1. 'ifconfig'사용-네트워크 케이블이 연결되어 있지만 네트워크가 올바르게 구성되지 않았거나 현재 작동하지 않기 때문입니다.
2. 호스트 핑-제품이 알 수없는 네트워크 구성 및 알 수없는 호스트를 사용하여 LAN 내에 있기 때문에.

/ proc 파일 시스템에서 사용할 수있는 상태가 있습니까 (다른 모든 것이 있습니까)?

Linux 세계는 아이콘 트레이에서 팝업되는 자체 Windows 버전 버블을 어떻게 사용하여 네트워크 케이블을 막았다 고 가정합니까?

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켄트 프레드릭 과 로타 , 당신의 대답은 모두 내 필요를 충족시킵니다 ... 많은 감사합니다! 내가 어느 것을 사용할 것인가 ... 나는 아직도 모른다.

나는 당신을 정답으로 둘 수 없다고 생각합니까? 그리고 내가 당신을 선택하는 것이 아마 당신에게 공평합니다. 내가 생각하는 동전을 뒤집어? 다시 한 번 감사합니다!

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당신은 노드를보고 싶어

/ sys / class / net /

나는 내 실험 :

전선 연결 :

eth0/carrier:1
eth0/operstate:unknown

와이어 제거 :

eth0/carrier:0
eth0/operstate:down

다시 연결 한 전선 :

eth0/carrier:1
eth0/operstate:up

_{사이드 트릭 : 한 번에 모든 속성을 쉽게 수확 할 수 있습니다.}

grep "" eth0/* 

이것은 멋진 key:value쌍 목록을 형성합니다 .

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ethtool 을 사용할 수 있습니다 :

$ sudo ethtool eth0
Settings for eth0:
    Supported ports: [ TP ]
    Supported link modes:   10baseT/Half 10baseT/Full
                            100baseT/Half 100baseT/Full
                            1000baseT/Full
    Supports auto-negotiation: Yes
    Advertised link modes:  10baseT/Half 10baseT/Full
                            100baseT/Half 100baseT/Full
                            1000baseT/Full
    Advertised auto-negotiation: Yes
    Speed: 1000Mb/s
    Duplex: Full
    Port: Twisted Pair
    PHYAD: 0
    Transceiver: internal
    Auto-negotiation: on
    Supports Wake-on: umbg
    Wake-on: g
    Current message level: 0x00000007 (7)
    Link detected: yes

링크 상태 만 얻으려면 grep을 사용할 수 있습니다.

$ sudo ethtool eth0 | grep Link
    Link detected: yes

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'ip monitor'를 사용하여 REAL TIME 링크 상태를 변경하십시오.

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cat /sys/class/net/ethX 가장 쉬운 방법입니다.

인터페이스가 작동해야합니다. 그렇지 않으면 잘못된 인수 오류가 발생합니다.

먼저 :

ifconfig ethX up

그때:

cat /sys/class/net/ethX

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On the low level, these events can be caught using rtnetlink sockets, without any polling. Side note: if you use rtnetlink, you have to work together with udev, or your program may get confused when udev renames a new network interface.

The problem with doing network configurations with shell scripts is that shell scripts are terrible for event handling (such as a network cable being plugged in and out). If you need something more powerful, take a look at my NCD programming language, a programming language designed for network configurations.

For example, a simple NCD script that will print "cable in" and "cable out" to stdout (assuming the interface is already up):

process foo {
    # Wait for device to appear and be configured by udev.
    net.backend.waitdevice("eth0");
    # Wait for cable to be plugged in.
    net.backend.waitlink("eth0");
    # Print "cable in" when we reach this point, and "cable out"
    # when we regress.
    println("cable in");   # or pop_bubble("Network cable in.");
    rprintln("cable out"); # or rpop_bubble("Network cable out!");
                           # just joking, there's no pop_bubble() in NCD yet :)
}

(internally, net.backend.waitlink() uses rtnetlink, and net.backend.waitdevice() uses udev)

The idea of NCD is that you use it exclusively to configure the network, so normally, configuration commands would come in between, such as:

process foo {
    # Wait for device to appear and be configured by udev.
    net.backend.waitdevice("eth0");
    # Set device up.
    net.up("eth0");
    # Wait for cable to be plugged in.
    net.backend.waitlink("eth0");
    # Add IP address to device.
    net.ipv4.addr("eth0", "192.168.1.61", "24");
}

The important part to note is that execution is allowed to regress; in the second example, for instance, if the cable is pulled out, the IP address will automatically be removed.

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There exists two daemons that detect these events:

ifplugd and netplugd

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Most modern Linux distributions use NetworkManager for this. You could use D-BUS to listen for the events.

If you want a command-line tool to check the status, you can also use mii-tool, given that you have Ethernet in mind.

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I use this command to check a wire is connected:

cd /sys/class/net/
grep "" eth0/operstate

If the result will be up or down. Sometimes it shows unknown, then you need to check

eth0/carrier

It shows 0 or 1

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Some precisions and tricks

1. I do all this as normal user (not root)

2. Grab infos from dmesg

   Using dmesg is one of the 1st things to do for inquiring current state of system:

   dmesg | sed '/eth.*Link is/h;${x;p};d'
   

   could answer something like:

   [936536.904154] e1000e: eth0 NIC Link is Down
   

   or

   [936555.596870] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
   

   depending on state, message could vary depending on hardware and drivers used.

   Nota: this could by written dmesg|grep eth.*Link.is|tail -n1 but I prefer using sed.

   dmesg | sed '/eth.*Link is/h;${x;s/^.*Link is //;p};d'
   Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
   
   dmesg | sed '/eth.*Link is/h;${x;s/^.*Link is //;p};d'
   Down
   

3. Test around /sys pseudo filesystem

   Reading or writting under /syscould break your system, especially if run as root! You've been warned ;-)

   This is a pooling method, not a real event tracking.

   cd /tmp
   grep -H . /sys/class/net/eth0/* 2>/dev/null >ethstate
   while ! read -t 1;do
       grep -H . /sys/class/net/eth0/* 2>/dev/null |
           diff -u ethstate - |
           tee >(patch -p0) |
           grep ^+
     done
   

   Could render something like (once you've unplugged and plugged back, depending ):

   +++ -   2016-11-18 14:18:29.577094838 +0100
   +/sys/class/net/eth0/carrier:0
   +/sys/class/net/eth0/carrier_changes:9
   +/sys/class/net/eth0/duplex:unknown
   +/sys/class/net/eth0/operstate:down
   +/sys/class/net/eth0/speed:-1
   +++ -   2016-11-18 14:18:48.771581903 +0100
   +/sys/class/net/eth0/carrier:1
   +/sys/class/net/eth0/carrier_changes:10
   +/sys/class/net/eth0/duplex:full
   +/sys/class/net/eth0/operstate:up
   +/sys/class/net/eth0/speed:100
   

   (Hit Enter to exit loop)

   Nota: This require patch to be installed.

4. In fine, there must already be something about this...

   Depending on Linux Installation, you could add if-up and if-down scripts to be able to react to this kind of events.

   On Debian based (like Ubuntu), you could store your scripts into

   /etc/network/if-down.d
   /etc/network/if-post-down.d
   /etc/network/if-pre-up.d
   /etc/network/if-up.d
   

   see man interfaces for more infos.

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tail -f /var/log/syslog | grep -E 'link (up|down)'

or for me faster gets:

tail -f /var/log/syslog | grep 'link \(up\|down\)'

It will listen to the syslog file.

Result (if disconnect and after 4 seconds connect again):

Jan 31 13:21:09 user kernel: [19343.897157] r8169 0000:06:00.0 enp6s0: link down
Jan 31 13:21:13 user kernel: [19347.143506] r8169 0000:06:00.0 enp6s0: link up

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on arch linux. (im not sure on other distros) you can view the operstate. which shows up if connected or down if not the operstate lives on

/sys/class/net/(interface name here)/operstate
#you can also put watch 
watch -d -n -1 /sys/class/net/(interface name here)/operstate

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You can use ifconfig.

# ifconfig eth0 up
# ifconfig eth0

If the entry shows RUNNING, the interface is physically connected. This will be shown regardless if the interface is configured.

This is just another way to get the information in /sys/class/net/eth0/operstate.

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I was using my OpenWRT enhanced device as a repeater (which adds virtual ethernet and wireless lan capabilities) and found that the /sys/class/net/eth0 carrier and opstate values were unreliable. I played around with /sys/class/net/eth0.1 and /sys/class/net/eth0.2 as well with (at least to my finding) no reliable way to detect that something was physically plugged in and talking on any of the ethernet ports. I figured out a bit crude but seemingly reliable way to detect if anything had been plugged in since the last reboot/poweron state at least (which worked exactly as I needed it to in my case).

ifconfig eth0 | grep -o 'RX packets:[0-9]*' | grep -o '[0-9]*'

You'll get a 0 if nothing has been plugged in and something > 0 if anything has been plugged in (even if it was plugged in and since removed) since the last power on or reboot cycle.

Hope this helps somebody out at least!

참고URL : https://stackoverflow.com/questions/808560/how-to-detect-the-physical-connected-state-of-a-network-cable-connector