Re: forwarding didn't work if wlan0 is member of a bridge

From: Olivier Cochard-Labbé <olivier_at_cochard.me>
Date: Tue, 12 Jan 2016 23:00:43 +0100
On Tue, Jan 12, 2016 at 9:52 PM, Alexander V. Chernikov <
melifaro_at_freebsd.org> wrote:

>
> Could you show 'netstat -rn' output when one of bridge members is down?
> Btw, I tried to reproduce it today (but, with ix0 instead of wlan0) and I
> wasn't able to trigger the problem.
>
>
​Sure,

here some output with the re1 (member of bridge) unplugged:

root_at_
​fbsd-router
:~ # ifconfig bridge0
bridge0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu
1500
        ether 02:6b:c0:de:b8:00
        inet 1.1.1.1 netmask 0xffffff00 broadcast 1.1.1.255
        nd6 options=9<PERFORMNUD,IFDISABLED>
        groups: bridge
        id 00:00:00:00:00:00 priority 32768 hellotime 2 fwddelay 15
        maxage 20 holdcnt 6 proto rstp maxaddr 2000 timeout 1200
        root id 00:00:00:00:00:00 priority 32768 ifcost 0 port 0
        member: wlan0 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP>
                ifmaxaddr 0 port 5 priority 128 path cost 33333
        member: re1 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP>
                ifmaxaddr 0 port 2 priority 128 path cost 55

root_at_
​fbsd-router
:~ # ifconfig re1
re1: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> metric 0
mtu 1500

options=82099<RXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,WOL_MAGIC,LINKSTATE>
        ether 00:0d:b9:3c:ae:25
        nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
        media: Ethernet autoselect (none)
        status: no carrier
root_at_
​fbsd-router​
:~ # netstat -r
​4​
n
Routing tables

Internet:
Destination        Gateway            Flags     Netif Expire
1.0.0.0/24         link#1             U           re0
1.0.0.1            link#1             UHS         lo0
1.1.1.0/24         link#6             U       bridge0
1.1.1.1            link#6             UHS         lo0
127.0.0.1          link#4             UH          lo0

During this "one-member-unplugged", the freebsd-router can still ping each
hosts on different connected interface, it just "refuse" to forward between
its interfaces:

root_at_fbsd-router:~ # ping 1.1.1.2 (the wireless client connected to wlan0,
member of the bridge0 interface)
PING 1.1.1.2 (1.1.1.2): 56 data bytes
64 bytes from 1.1.1.2: icmp_seq=0 ttl=64 time=4.600 ms
64 bytes from 1.1.1.2: icmp_seq=1 ttl=64 time=5.878 ms
^C
--- 1.1.1.2 ping statistics ---
2 packets transmitted, 2 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 4.600/5.239/5.878/0.639 ms
root_at_fbsd-router:~ # ping 1.0.0.2 (an host on the LAN0)
PING 1.0.0.2 (1.0.0.2): 56 data bytes
64 bytes from 1.0.0.2: icmp_seq=0 ttl=64 time=0.282 ms
64 bytes from 1.0.0.2: icmp_seq=1 ttl=64 time=0.280 ms
^C
--- 1.0.0.2 ping statistics ---
2 packets transmitted, 2 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.280/0.281/0.282/0.001 ms
root_at_fbsd-router:~ # arp -na
? (1.1.1.1) at 02:6b:c0:de:b8:00 on bridge0 permanent [bridge]
? (1.1.1.2) at 00:c0:ca:7e:8b:fe on bridge0 expires in 1055 seconds [bridge]
? (1.0.0.1) at 00:0d:b9:3c:ae:24 on re0 permanent [ethernet]
? (1.0.0.2) at 0c:c4:7a:6b:a6:d3 on re0 expires in 1106 seconds [ethernet]

​And the wireless client (1.1.1.2) can still ping the fbsd-router bridge
interface (1.1.1.1) too (for answering to the Adrian question).​

Now I replug re1:

root_at_fbsd-router:~ # ifconfig re1
re1: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> metric 0
mtu 1500

options=82099<RXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,WOL_MAGIC,LINKSTATE>
        ether 00:0d:b9:3c:ae:25
        nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
        media: Ethernet autoselect (1000baseT <full-duplex,master>)
        status: active

and here are netstat output (no changes with previous):

root_at_fbsd-router:~ # netstat -r4n
Routing tables

Internet:
Destination        Gateway            Flags     Netif Expire
1.0.0.0/24         link#1             U           re0
1.0.0.1            link#1             UHS         lo0
1.1.1.0/24         link#6             U       bridge0
1.1.1.1            link#6             UHS         lo0
127.0.0.1          link#4             UH          lo0

Because you didn't reach to reproduce with ix0 in place of wlan0, I've did
some modification to my bridge setup:
1. In place of using re1+wlan0, I've put re1+re2 in the bridge0. And I've
connected an host on re2: I didn't reach to reproduce the problem too, then I
confirm we didn't have this bug with 2 Ethernet Interfaces.

2. In place of using PCI ath(4) (Atheros 9280), I've plugged an USB rum(4)
(old Ralink) and configured it as wlan0 like was the ath0: the bridge0 was
reverted to re1+wlan0.
And I reach to reproduce the problem with a different wireless card: This
thread seems correctly belong to the "wireless" mailing-list :-)
Received on Tue Jan 12 2016 - 21:01:06 UTC

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