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

[Michael Rack]

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?

------------------------
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
-- 
RSM Freilassing                 Tel.: +49 8654 607110
Nocksteinstr. 13                Fax.: +49 8654 670438
D-83395 Freilassing            www.rsm-freilassing.de

-------------- next part --------------
DebugLevel      0
IpVersion       4
FIBMetric       "flat"
ClearScreen     yes

Hna4
{
        192.168.90.0     255.255.255.224
}

RtTable 100
RtTableDefault 253

AllowNoInt      yes
TosValue        16

Willingness             3
LinkQualityLevel        2
LinkQualityAlgorithm    "etx_ff"

UseHysteresis   no
Pollrate        0.05
NicChgsPollInt  3.0

TcRedundancy    2
MprCoverage     1

LoadPlugin "olsrd_txtinfo.so.0.1"
{
        PlParam "port" "2001"
        PlParam "listen" "0.0.0.0"
        PlParam "Host" "127.0.0.1"
}

InterfaceDefaults
{
        HelloInterval           2.0
        HelloValidityTime       60.0
        TcInterval              5.0
        TcValidityTime          120.0
        MidInterval             5.0
        MidValidityTime         120.0
        HnaInterval             5.0
        HnaValidityTime         120.0
}

Interface "tap0"
{
        LinkQualityMult         default 0.2
        Ip4Broadcast            255.255.255.255
        Mode "ether"
}

Interface "eth0"
{
        Ip4Broadcast            255.255.255.255
        Mode "ether"
}