[CentOS] Persisting iproute2 routes and rules

Greetings!

I have defined a few routes and rules with:

ip route add ...
ip rule add ...

And now I'd like to persist those so they're loaded when the system boots up.

I'm doing this by means of calling a specific script from
/etc/rc.d/rc.local but I believe there must be something cleaner than
that, like another existing file.

Thanks in advance,
Diogo