Recovery State Machine

The recovery state machine is described in the following diagram:

A slight change in the actual implementation: upon exiting from the "check connectivity" state when connection status is "disconnected", if the latest recovery was router recovery and it was performed within the last hour, then router recovery is skipped and modem recovery is performed. This modification was added after I saw that sometimes router recovery succeeds but after a short time connectivity is lost. Then if router recovery is done connectivity returns again for a short time and so on. So if the last recovery was router recovery and it was done within the last hour, modem recovery is performed first. If connectivity is not resumed, then router recovery is attempted, according to the state diagram above.