[strongSwan] Split tunneling with Strongswan 5.x

[kgardenia42]

Hi,

If I wanted to *only* tunnel traffic destined for (say) 172.16.32.0/24
but wanted the (IOS based, IKEv1) clients to send everything else
direct (not via the VPN tunnel).  (I believe this is called
split-tunneling but maybe that is not correct).

It seems that the mechanics of that should be to push out a route to
the client which it should tunnel data destined for.  I have read the
manual and am wondering if "rightsubnet" serves this purpose?
Currently I have this set to 0.0.0.0/0 for my config.

Am I on the right track with rightsubnet or otherwise how should i go
about this?  I just need some rough pointers.  Or do I need a plugin
for this?

Thanks,