[Bridge] brctl problem: broadcast doesn't get through

["Ireneusz Szcześniak" <irek.szczesniak@gmail.com>]

Hi,

I'm creating a bridge, and then add to it two tap interfaces. No 
physical interface is added to the bridge. These are the commands:

brctl addbr test
ip tuntap add mode tap tap0
ip tuntap add mode tap tap1
ifconfig test up
ifconfig tap0 up
ifconfig tap1 up
brctl addif test tap0
brctl addif test tap1

The problem is that the bridge doesn't seem to work correctly. I sent 
through tap0 some broadcast frames (WOL frames), and they didn't reach 
tap1. I was sending packets with:

etherwake -b -i tap0 00:00:00:00:00:00

The tshark command for tap0 showed the frames being sent with tap0, 
but another tshark for tap1 didn't show them.

Then I added to tap0 the IP address 192.168.10.1/24, and did:

arping 192.168.1.2

I saw ARP request broadcast frames on tap0, but they didn't reach tap1.

This is the output of ifconfig for test, tap0, and tap1 interfaces:

root@computer:~# ifconfig test
test Link encap:Ethernet HWaddr 02:07:b1:eb:2c:2a
inet6 addr: fe80::944b:d9ff:fe10:b240/64 Scope:Link
UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:19 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:3377 (3.2 KiB)

root@computer:~# ifconfig tap0
tap0 Link encap:Ethernet HWaddr 02:07:b1:eb:2c:2a
inet addr:192.168.10.0 Bcast:192.168.10.255 Mask:255.255.255.0
inet6 addr: fe80::7:b1ff:feeb:2c2a/64 Scope:Link
UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:278 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)

root@computer:~# ifconfig tap1
tap1 Link encap:Ethernet HWaddr b2:ee:2c:f9:d5:0d
inet6 addr: fe80::b0ee:2cff:fef9:d50d/64 Scope:Link
UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:19 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)

The output of the brctl:

root@computer:~# brctl show
bridge name bridge id STP enabled interfaces
pan0 8000.000000000000 no
test 8000.0207b1eb2c2a no tap0
tap1
root@computer:~# brctl showmacs test
port no mac addr is local? ageing timer
1 02:07:b1:eb:2c:2a yes 0.00
2 b2:ee:2c:f9:d5:0d yes 0.00

The output of route:

root@computer:/home/iszczesniak# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.2.0 0.0.0.0 255.255.255.0 U 2 0 0 eth1
192.168.10.0 0.0.0.0 255.255.255.0 U 0 0 0 tap0
169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 eth1
0.0.0.0 192.168.2.1 0.0.0.0 UG 0 0 0 eth1

What am I doing wrong?


Thanks,
Irek

-- 
Ireneusz (Irek) Szczesniak
http://www.irkos.org