[lwip-users] simhost linux-bridge

[Andreas Becker]

Hi All,

I develop my lwIP applications with linux using the TAPif.
When if I assign an private network to the lwIP Stack everything works fine.

Now I tried to give the lwIP Stack an  IP-Number of my lokal Network. Let's 
say: 192.168.0.10.

So I use the linux (ethernet-) bridge with an real ethernet interface (eth1) 
on one side and the tap0 device on the other side. 
For this it is usefull to remove the IP address of both devices.
# ifconfig tap0 0.0.0.0 promisc
# ifconfig eth1 0.0.0.0 promisc

Then build the bridge with brctl (bridge-utils):
// create empty bridge device ( like eth0)
# brctl addbr br0        

// set the IP of the bridge 
# ifconfig br0 

// eth1 is a member of the bridge
# brctl addif br0 eth1

//  tap0 is also a member of the bridge
# brctl addif br0 tap0

The setup is done. But it works only in one direction:
If I ping the lwIP Stack from another Host. The pings go from the Ethernet to 
the "br0" device to the "tap0" device. There the lwIP generates an answer an 
sends it to the asking host (correct IP + Ethernet-Mac). But then the 
packages blow up. They do not go back to the "br0" device. 
(seen with Ethereal)

Did anybody know, why this does not work in both direction's (ipv4.forward is 
enabled) ?

The only thing I wanted to do is to give the lwIP-Stack the posibility to 
send and recieve broadcasts to my lokal network. Any Ideas?

Thanks for your help!

-- 
Dipl.-Ing.(FH) Andreas Becker
Entwicklung

dSys e.K.
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D-89077 Ulm
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