tap interfaces disabled in linux bridge

https://serverfault.com/questions/540831/tap-interfaces-always-disabled-in-linux-bridge

tap interfaces always disabled in linux bridge

I have a physical interface eth0, and I want to create two virtual interfaces and bridge them with eth0. For this purpose I do:

#Create the virtual interfacestunctl -t tap0tunctl -t tap1ifconfig tap0 upifconfig tap1 up#Create the bridgebrctl addbr br0brctl stp br0 offbrctl addif br0 eth0brctl addif br0 tap0brctl addif br0 tap1#Turning up the bridgeifconfig br0 up

However my problem if that the tap interfaces always appear disabled in the bridge, and no traffic flows to them.

$brctl show br0bridge name bridge id       STP enabled interfacesbr0     8000.080027cabeba   no          eth2                                        tap0                                        tap1$brctl showstp br0br0 bridge id      8000.080027cabeba designated root    8000.080027cabeba root port         0            path cost          0 max age          20.00         bridge max age        20.00 hello time        2.00         bridge hello time      2.00 forward delay        15.00         bridge forward delay      15.00 ageing time         300.01 hello timer           0.00         tcn timer          0.00 topology change timer     0.00         gc timer         298.42 flags          eth2 (1) port id        8001            state            forwarding designated root    8000.080027cabeba   path cost          4 designated bridge  8000.080027cabeba   message age timer      0.00 designated port    8001            forward delay timer   12.97 designated cost       0            hold timer         1.24 flags          tap0 (2) port id        8002            state              disabled designated root    8000.080027cabeba   path cost        100 designated bridge  8000.080027cabeba   message age timer      0.00 designated port    8002            forward delay timer    0.00 designated cost       0            hold timer         0.00 flags          tap1 (3) port id        8003            state              disabled designated root    8000.080027cabeba   path cost        100 designated bridge  8000.080027cabeba   message age timer      0.00 designated port    8003            forward delay timer    0.00 designated cost       0            hold timer         0.00 flags    

Is there any way to set the tap interfaces in forwarding state? I do not understand why they are not because STP is disabled.

Cheers

Daniel

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Answer

Carrier (IFF_RUNNING) is only set on a tap when a user has the device handle open.

For a persistent tap created with tunctl, you need an application which attaches to the tap, eg:

• http://backreference.org/2010/03/26/tuntap-interface-tutorial/

or

        http://blog.csdn.net/ztguang/article/details/72890346