Hi,

I just verified again.
The ! route problem seems to occur during startup of a host.
The two hosts are literally kept next to each other.
10.0.0.1 is the gateway to the internet.

Below is the routing table for host 10.0.0.3

$ route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
10.0.0.0        *               255.255.255.0   U     0 0        0 wlan1
10.0.0.0        -               255.255.255.0   !     -1 -        0 -
10.0.0.1        -               255.255.255.255 !H    -1 -        0 -
192.168.0.0     -               255.255.255.0   !     -1 -        0 -
192.168.0.7     -               255.255.255.255 !H    -1 -        0 -


For this particular test, 10.0.0.3 was up and running first and then after a few minutes I started 10.0.0.1
Both are configured as ad-hoc networks
I restarted the babeld service multiple times on 10.0.0.1 but the routing table of 10.0.0.3 won't fix.
After I restart babeld service on 10.0.0.3, routes are fine.

-----------

Also I verified that
-C 'redistribute proto 3 allow'
works as intended, but only after I restart the babeld service on 10.0.0.3 after which all the routes were set correctly.

Thanks,
Regards,



On Wednesday 08 January 2014 04:43 PM, Harshal Vora wrote:
Hi Matthieu, Thanks for the reply.
My reply inline.


On Wednesday 08 January 2014 04:11 PM, Matthieu Boutier wrote:
But on few occasions, it inserts negative routes with Flag set to !H and metric 
set to -1 for hosts which are in direct range of each other.
I don't know what is "!", perhaps "unreachable". This seems (for the moment) 
quite normal : you're moving, so the metric changes (it will increase at some point), and at some 
point, you will be out of feasible routes. Babel then must consider that the node has failed, and 
set the route as unreachable to avoid some routing loops. It is well explained in the 2.8 paragraph 
of the RFC :
        http://www.ietf.org/rfc/rfc6126.txt

        ! is "Reject Route" as mentioned here.
        http://unixhelp.ed.ac.uk/CGI/man-cgi?route+8
        I agree with you that if the route is unreachable then babel
        must consider that the node has failed.
        But this happened even when the hosts were kept stationary
        near to each other.

        The RFC mentions

        *the time for which such a route
            must be maintained should be the worst-case propagation time of the
            retraction of the route to C.*

        Is there any value for this then I can  try waiting for so long the 
next time

These negative routes remain persistent until i restart babeld and sometimes 
until i reboot the host.
Shouldn't it be auto-corrected?
It should. How many time before reboot ?

        I waited for approximately 2-3 minutes before reboot. In the
        mean time I was restarting babeld
        Also I enabled level 3 logs for babeld. I could see requests
        coming in from the hosts for which there were unreachable routes.

Is there any way to fix this?
What version (or commit) are you using ? Which OS ?

This happened in two different hosts (Both arm processors, babeld v. 1.3.1-1 from apt-get)
        1) Hackberry
                        kernel: linux-sunxi-v3.4.24-r1
                        OS: Ubuntu 12.10  --
        
|http://cdimage.ubuntu.com/ubuntu-core/releases/12.10/release/ubuntu-core-12.10-core-armhf.tar.gz|

        2) Raspberry pi Model B
                Kernel: rasppi_linux_rpi-3.6.y
                OS: raspbian


Also, is it possible to redistribute routes added with proto kernel or boot?
Yes. Proto boot is avoided by default, so you must add a configuration line, as 
:
        redistribute proto 3 allow

        I will give it a try. Thanks.
        From the file /etc/iproute2/rt_protos

        2       kernel
        3       boot
        4       static

        Thus I assume 3 will enable routes enabled by boot protocol


Best regards,
Matthieu



Regards,

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