[Olsr-dev] Use Case for rttable_tunnel

[Henning Rogge]

On Wed March 3 2010 11:46:55 Sven-Ola Tuecke wrote:
> Hey,
> 
> the (new) rttable_tunnel parameter as well as the following defaults will
> break some features:
> 
> #define DEF_RTTABLE_DEFAULT  112
> #define DEF_RTTABLE_TUNNEL   113
> 
> Obviously, the tunnel-default-route should not be executed if olsrd sets a
> standard default route. I presume, the author has some "ip rules add" in
> mind otherwise it's useless...?
OLSR (if policy routing is activated) use the rtnetlink socket to set up the 
necessary policy rules for a working setup.

If policy routing is deactivated, all rules are written into the default 
table.

> Where I expect conflicts: at a given time only ONE default route will be
> used by a particular station/user. I use that rttable_default setting for
> users which will join the mesh but do not want to share their inet
> connection (aka. my-Internet-for-me-alone). He/she will (of course) not
> block inet traffic generated by others. As a second use case, there is the
> "dyn_gw_plain" stuff. Which (if the gateway is unusable) shifts the
> 254-default route in a background table only valid for the current device.
> This is necessary, otherwise you cannot determine if that gateway will
> come up again.
if you have a default route which has a policy priority better than 
rttable_tunnel (and rttable_default) and only applies to the local device, you 
still should be able to get this setting working I think.

> Can someone shed some light on this setting? (BTW: there will be no
> IPv6-ipip-tunnel without backporting some 2.6.x code to linux-2.4)
ipv6 on kernel 2.4 is a problem because we have no policy routing there (for 
ipv6). So kernel 2.4 devices might be not a good choice for using IPv6.

Henning Rogge

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