Tinc

https://silvenga.com/deploy-a-tinc-mesh-vpn-running-tap/

http://www.allsundry.com/2011/04/10/tinc-better-than-openvpn/

All the setup you need:

In /etc/netname/tinc.conf:
Name = host1
ConnectTo = host2

In /etc/netname/tinc-up
ifconfig $INTERFACE 192.168.XX.1 netmask 255.255.0.0

# Generate keypairs for host
tincd -n netname -K

# Create file for this host. Prepend to /etc/netname/hosts/host1
Address = host1.full.domain.com
Subnet = 192.168.XX.0/24