How to make a caching direct proxy?

Question

proxy

Hey! You need a transparent proxy between LAN and WAN with the following properties:

• if the WAN is available, the packet is sent to its destination;
  
• if the WAN is not available, the packet is saved, and when the link is restored, it is sent to its destination, while the client in the LAN must be sure that the packet has flown away.
  

In the second case, packets must be stored/sent in order of arrival.
The proxy must work at the network layer - and then it's a router, or at the HTTP protocol layer.
If you limit yourself to the HTTP level, then you can try to make such a proxy based on some Celery, but I want a ready-made solution.

Answer 1

Suddenly!
Yes, this is Delay-tolerant networking , Interplanetary Internet and all that. There is even an implementation on SF .
I will think whether such a microscope is suitable for my tasks.