Currently we used forward block syncing, while with this changes we do two step backwards header sync and then forward block sync using already known headers. This enables the node to know in advance the tip of the peers they will sync from
Add an additional byte to SessionBitFlags to accommodate SESSION_REFINE
and reduce the risk of logic errors.
Additionally:
* `!SESSION_SEED & !SESSION_REFINE` is now referred to as `SESSION_DEFAULT`
* `!SESSION_REFINE` is refered to as `SESSION_NET`.
* `SESSION_ALL` has been deleted since it was conceptually out-dated
* Binaries have been updated.
Add an additional byte to SessionBitFlags to accommodate SESSION_REFINE
and reduce the risk of logic errors.
Additionally:
* `!SESSION_SEED & !SESSION_REFINE` is now referred to as `SESSION_DEFAULT`
* `!SESSION_REFINE` is refered to as `SESSION_NET`.
* `SESSION_ALL` has been deleted since it was conceptually out-dated
* Binaries have been updated.
* Move greylist refinery and ping self process into Session.
* Remove hosts/ submodule and return store to net/hosts.rs
* Temporarily disable Gold/ Grey list upgrade and downgrade (we will move into RefineSession)
this leads to cleaner code since depending on the use case we still do
different things with the HostState following move_host(). However it
does mean that unregister() has to be called manually in some cases.
Previously there was a bug which happened v rarely in which:
> Outbound and Manual Session are waiting on a stop signal
> Outbound/ Manual receives a stop signal, de-registers channel (in move_host)
> Channel is selected by Slot 1 to be connected to, state is changed to Connect
> remove_sub_on_stop() receives a stop signal, de-registers channel
> Channel is selected by Slot 5 connected to, state is changed to Connect
> Slot 1 connects, state is changed to Connected
> Slot 5 connects -> panic!
To avoid this happening, we move unregister() out of move_host and perform the sequence:
recv stop signal -> move_host to greylist (if outbond/manual) -> unregister()
We do this inside the shared method remove_sub_on_stop to ensure the execution path always happens in the same way.
