On 04/26/2013 09:30 PM, cmsv wrote:
I have reached a point where i need to start using the uevent functionality to work around some network scenarios when the gateways lose internet access but i am having a bit of a difficult time understanding how to do it since making use of uevents which is something new to me.
The explanation here is not helping much either http://www.open-mesh.org/projects/batman-adv/wiki/Uevent
and i understand that i might need to go to the basics to understand it and learn how to code.
My need to use uevents to change a nodes behaviour is to change a node from server to client and vice versa when it loses connectivity to the WAN (not for example losing connectivity to the dsl router that is actually the gateway but that has the node as a LAN client)
I am assuming that uevents will allow me to work with this physical setup correct?
As far as i understand now and if i am not mistaken when a gateway loses WAN connectivity the node that is making use of uevents will change the node from "server" to "client" on batman-adv .
That won't happen automatically, you need some userspace script to handle the event and change batman-adv gw mode
Please check
https://colectivo.altermundi.net/projects/altermesh-packages/repository/show...
which in turn depends on
https://colectivo.altermundi.net/projects/altermesh-packages/repository/show...
you should read the source code of batman-adv-auto-gw-mode (just a few lines / files) and i'll comment a bit about it along this email,
you can grab the "binaries" (actually ipk-packaged bash scripts) and try them right away
http://chef.mesh.altermundi.net/downloads/r36139/ar71xx/packages/batman-adv-... http://chef.mesh.altermundi.net/downloads/r36139/ar71xx/packages/watchping_2...
mind you, the default behaviour of sending the hostname in dhcp requests has changed in recent trunk builds, so this feature might not work reliable; but on the other hand, that might not make any difference in your scenario :) (you don't seem to care about hostnames)
Now my question is if i can also make it to change the dhcp setup from dhcp server to inactive and receive it´s dhcp service from another gateway node
In theory something like this would be executed on openwrt when a gateway node detects no connectivity to the wan:
uci set batman-adv.bat0.gw_mode=client ; uci commit batman-adv ; batman-adv reboot ; uci set dhcp.lan.force=0 ; uci set dhcp.lan.ignore=1 ; uci commit dhcp ; /etc/init.d/dnsmasq restart ;
when it detects wan connectivity it will want to become a server and will auto execute:
uci set batman-adv.bat0.gw_mode=server ; uci commit batman-adv ; batman-adv reboot ; uci set dhcp.lan.force=1 ; uci set dhcp.lan.ignore=0 ; uci commit dhcp ; /etc/init.d/dnsmasq restart ;
A small script can even be made in order so simplify things either automatically or manually and lets call it: gateway-mode client-mode
this would equiv to
/etc/watchping/wan-ok.d/batman-gw /etc/watchping/wan-fail.d/batman-gw
Upon detecting no WAN connectivity the script will be activated.
Am i on the right track so far (at least in theory) ?
Now the second part is how to detect WAN connectivity which is different from noticing that there is no connectivity to the actual gw router that has the node on it's LAN.
I thought about a ping test to a few address from which after 100% loss reply from all; something or Uevent will activate the gateway/client mode script but it creates another problem ahead.
In a quick conversation with ordex on irc i understand that i have to invoke the wiki docs uevent functions with the parameters i want at the moment i decide. This can be the gateway/client mode script
Yes, in my case /etc/hotplug.d/net/99-batman-gw
correct ?
Since uevent is something new to me; can someone recommend some freshman tutorial that may take me in the right direction. I have no clue where or how to start looking to code it and also when coded; where will it be added.
I also would like to ask anyone that has uevent working how they are using it for the same type of need and maybe even share some recipe.