[Olsr-users] Flushing routes when an interface gets removed

[Ferry Huberts]

On 06/03/14 17:52, Michael Rack wrote:
> Hi!
>
> I use olsrd v0.6.6 with two interfaces:
>
>      * tap0 = VPN Tunnel over DSL for Backup reasons
>      * eth0 = 1 GBit Ethernet Port
>
> The tap0-Interface is installed static via (ip tuntap add dev tap0 mode
> tap).
> Routes via tap0 are devaluated (LinkQualityMult default 0.2), so eth0 is
> most the preference.
>
> Now the strange behavior:
>
> When the tap0-Interface get up and running, olsrd adds the interface
> "olsrd[28954]: Adding interface tap0". The additional routes get
> inserted and the internal routes will be calculated. So far no problem,
> and just as wanted.
>
> But when i shutdown the VPN-Link (there are no routes via tap0 active)
> the complete routing table gets flushed. So i have a short takeout up to
> 5 seconds.
>
> The LogFile says: "olsrd[28954]: Removing interface vpn01". Thats ok,
> but why get all routes via eth0 also flushed?

It shouldn't.
Henning, ideas?

>
> ------------------------
> VPN IS ACTIVE:
>
> ~ # ip route show table default
> default via ***.***.***.*** dev eth0 metric 2 onlink
>
> ~ # ip route show table oslr | grep 'tap0'
> {0 routes}
>
> ~ # ip route show table oslr | grep 'eth0'
> {88 routes}
>
>
> ------------------------
> SHUTDOWN VPN:
>
> ~ # ip route show table default
> {0 routes}
>
> ~ # ip route show table oslr | grep 'tap0'
> {0 routes}
>
> ~ # ip route show table oslr | grep 'eth0'
> {0 routes}
>
> after 5 seconds, the last commands return 88 inserted routes.
>
> ------------------------
> Log-File /var/log/messages
>
> Mar  6 17:34:48 myvpnrouter vtund[29019]: VTun client ver 3.X 09/18/2013
> started
> Mar  6 17:34:48 myvpnrouter vtund[29019]: Connecting to 80.255.15.136
> Mar  6 17:34:48 myvpnrouter vtund[29019]: Session
> myvpnrouter-dsl-backup[xxx.xxx.xxx.xxx] opened
> Mar  6 17:34:48 myvpnrouter olsrd[28954]: Writing '0' (was 0) to
> /proc/sys/net/ipv4/conf/vpn01/send_redirects
> Mar  6 17:34:48 myvpnrouter olsrd[28954]: Writing '0' (was 0) to
> /proc/sys/net/ipv4/conf/vpn01/rp_filter
> Mar  6 17:34:48 myvpnrouter olsrd[28954]: Adding interface vpn01
> Mar  6 17:34:48 myvpnrouter vtund[29019]: UDP connection initialized
> ......
> Mar  6 17:41:40 myvpnrouter vtund[29019]: Closing connection
> Mar  6 17:41:40 myvpnrouter vtund[29019]: Session
> myvpnrouter-dsl-backup[xxx.xxx.xxx.xxx] closed
> Mar  6 17:41:40 myvpnrouter vtund[29019]: Exit
> Mar  6 17:41:41 myvpnrouter olsrd[28954]: Removing interface vpn01
>
>
>
> Why is olsrd flushing all routes when a interface gets removed?
>
>
>
> Liebe Grüße aus Freilassing,
>
> Michael Rack
> RSM Freilassing
>
>

-- 
Ferry Huberts