Implement IPv4 Route Policy to prefer babel routes

[spolack]

Implement following changes which are preparing the migration towards using babel also for IPv4 - #964

• Add new Routing Tables to avoid babel routes compete with olsrd, which could lead to routing loops. We have to ensure that the routes get installed only in the appropriate tables, never in the default/main.

  babel-default # Contains default routes from babel
  babel-ff # Contains freifunk routes (hna) from babel
  olsr-default # Contains default routes from olsr
  olsr-ff #  Contains freifunk routes (hna) from olsr
  

• Setup routing policy in following order:

  babel-ff -> olsrd-ff -> babel-default -> olsrd-default
  

• Ensure that olsrd and babeld install IPv4 routes only in the appropriate tables. Unfortunately babeld is not able to install routes in different policies, therefore routes are installed in "intermediate" table babel-src, from which they are leaked conditionally into babel-ff and babel-default using bird2. In addition it has to be ensured that the babel-src table is also used to lookup IPv6 targets.

With these changes in place we have ensured that babeld and olsrd routes never compete and babel is prefered whenever a route is there, but if not it is routed using olsr.

[Noki]

Installed it on w38b-core an also my test router noki-core, so far without any issues. Seems to work exactly the same as before.

[spolack]

@Noki can you confirm the route policy and routing tables are filled accordingly to the scheme?

ip rule
ip -6 rule

ip route show table babel-ff
ip route show table olsr-ff
ip route show table babel-default
ip route show table olsr-default

[Noki]

@Noki can you confirm the route policy and routing tables are filled accordingly to the scheme?

ip rule
ip -6 rule

ip route show table babel-ff
ip route show table olsr-ff
ip route show table babel-default
ip route show table olsr-default

Yes, from my understanding that is the case. Looks good to me. Looking forward for a first babel-default route for IPv4 ;-)

[spolack]

I'd propose to depoloy that change to a few high traffic nodes like

• Sama
• Zwingli
• RHNK

in order to check for sideeffects we might have overseen yet at our stub sites.

[Noki]

Deployed to:

• w38b
• rhnk
• zwingli
• sama
• dorfplatz
• gruni73
• scharni

[PolynomialDivision]

If you look at the babel neighbours, we see that there is no ipv4 neighbours but ipv4 routes. Is that intended?

[Noki]

If you look at the babel neighbours, we see that there is no ipv4 neighbours but ipv4 routes. Is that intended?

@PolynomialDivision you might have spotted the routes from the f2a nodes etc. setup by patrick. They were in there before...

[PolynomialDivision]

@spolack what about announcing the default ipv4 via babeld?