[strongSwan] Handling of overlapping tunnel establishment

[Tobias Brunner]

Hi Joern,

> Immediately strongswan deletes Child SA of its own initiated tunnel

Stating this without also providing the reason for it (or at least a
log) makes it hard to help you.  If you are getting errors related to
reqids when the daemon attempts to install the IPsec policies, you
should update to 5.3.x.

Regards,
Tobias