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

This is actually the intended behaviour, right? The routed interface
is down, so the IP address on it and connected to it are unreachable.




-a

On 11 January 2016 at 14:52, Olivier Cochard-Labbé <olivier_at_cochard.me> wrote:
> After weeks of troubleshooting, at last I found how to reproduce this
> problem ;-)
>
> Here is the setup:
>
> LAN0 <--> [(re0) fbsd router (bridge0 addm re1 addm wlan0)] <--> Wireless
> LAN
>
> If interface re1 (bridge0 member with wlan0) is in "active" status
> (=ethernet cable plugged to something): I don't have any problem, all is
> working great for my wireless clients connected to wlan0: They can ping
> devices in LAN0.
> But once I've unplug the ethernet cable connected to re1 (bridge member
> with wlan0) and re1 state switch to "no carrier", Wireless LAN clients are
> not able to reach LAN0.
>
> Here is my rc.conf with simple subnetting for Adrian ;-)
>
> wlans_ath0="wlan0"
> ifconfig_wlan0="hostap channel 6"
> create_args_wlan0="wlanmode hostap"
> cloned_interfaces="bridge0"
> ifconfig_re0="inet 1.0.0.1/24"
> ifconfig_re1="up"
> ifconfig_bridge0="inet 1.1.1.1/24 addm re1 addm wlan0 up"
> gateway_enable="YES"
>
> And an example with re1 in "no carrier" status:
>
> 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
>
> => from a wireless LAN client (1.1.1.2) I'm trying to ping a host on LAN0
> (1.0.0.2):
>
> root_at_fbsd-router:~ # tcpdump -pni re0
> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
> listening on re0, link-type EN10MB (Ethernet), capture size 262144 bytes
> 23:38:04.466866 ARP, Request who-has 1.0.0.2 tell 1.0.0.1, length 28
> 23:38:04.467052 ARP, Reply 1.0.0.2 is-at 00:08:a2:09:c4:a2, length 46
> 23:38:04.467090 IP 1.1.1.2 > 1.0.0.2: ICMP echo request, id 72, seq 1,
> length 64
> 23:38:04.467226 IP 1.0.0.2 > 1.1.1.2: ICMP echo reply, id 72, seq 1, length
> 64
> 23:38:04.467300 IP 1.0.0.1 > 1.0.0.2: ICMP host 1.1.1.2 unreachable, length
> 36
> 23:38:05.483053 IP 1.1.1.2 > 1.0.0.2: ICMP echo request, id 72, seq 2,
> length 64
> 23:38:05.483259 IP 1.0.0.2 > 1.1.1.2: ICMP echo reply, id 72, seq 2, length
> 64
> 23:38:05.483318 IP 1.0.0.1 > 1.0.0.2: ICMP host 1.1.1.2 unreachable, length
> 36
> 23:38:06.387304 IP 1.1.1.2 > 1.0.0.2: ICMP echo request, id 72, seq 3,
> length 64
> 23:38:06.387466 IP 1.0.0.2 > 1.1.1.2: ICMP echo reply, id 72, seq 3, length
> 64
> 23:38:06.387514 IP 1.0.0.1 > 1.0.0.2: ICMP host 1.1.1.2 unreachable, length
> 36
> ^C
> 11 packets captured
> 11 packets received by filter
> 0 packets dropped by kernel
> 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 fc:64:ba:97:c0:ff on bridge0 expires in 1168 seconds [bridge]
> ? (1.0.0.1) at 00:0d:b9:3c:ae:24 on re0 permanent [ethernet]
>
> => The FreeBSD router answers "unreacheable" to the host: My wireless LAN
> client never get the ICMP reply.
>
> => Now I plug eth1 to a dummy machine (just for changing its status):
>
> 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>)
>         status: active
>
> => and I restart the same ping from the wireless LAN client:
>
> root_at_fbsd-router:~ # tcpdump -pni re0
> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
> listening on re0, link-type EN10MB (Ethernet), capture size 262144 bytes
> 23:44:08.597429 IP 1.1.1.2 > 1.0.0.2: ICMP echo request, id 74, seq 1,
> length 64
> 23:44:08.597660 IP 1.0.0.2 > 1.1.1.2: ICMP echo reply, id 74, seq 1, length
> 64
> 23:44:09.604447 IP 1.1.1.2 > 1.0.0.2: ICMP echo request, id 74, seq 2,
> length 64
> 23:44:09.604683 IP 1.0.0.2 > 1.1.1.2: ICMP echo reply, id 74, seq 2, length
> 64
> 23:44:10.609711 IP 1.1.1.2 > 1.0.0.2: ICMP echo request, id 74, seq 3,
> length 64
> 23:44:10.609874 IP 1.0.0.2 > 1.1.1.2: ICMP echo reply, id 74, seq 3, length
> 64
>
> => It's works :-)
>
> How the status of a member of the bridge can impact the routing behavior of
> other interfaces ?
> How to fix this problem ?
>
> Thanks
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