Implement an app to route cargo at a "transport hub"

[gnarea]

Describe the problem

Couriers currently have to stop at a location with access to the Internet so that they can relay their data. However, there's no reason why they couldn't just hand it over to another courier if the initial courier won't be able to stop by a location with access to the Internet.

Describe the solution you'd like

Like real-world couriers, this could be solved with a "transport hub":

• Last-mile couriers relay cargo between end users and the local transport hub.
• Long-distance couriers relay cargo between transport hubs.

Additionally, either type of courier may have a location with access to the Internet as one of its stops -- in fact, at least one courier route in any region must have one.

This transport hub app would have to keep track of the route for each courier that connects to it and the private gateways whose cargoes have gone through it recently (along with their corresponding routes), so that it route cargo to the appropriate routes.

Note that the app wouldn't need to know the actual stops in the routes. It just needs the id of the route, whether one of the stops provides access to the Internet and the id of any other transport hubs found in the route.

Additional context

See also:

• Allow couriers to relay cargo via other couriers relaynet-courier-android#495
• Make private gateways use a different identity key pair when communicating via couriers AwalaApp/specs#71
• Prevent a compromised courier from tracking cargo to/from private gateways AwalaApp/specs#54