Instead of assigning a privacy segment at connect, wait until we have
determined if this peer is on the same chain as us before we allocate a
peer slot.
This also helps us limit the amount of peers we send our bloom filter to.
This is done in several steps:
1. Separate my height from the remote peer heights.
Instead of assuming we have one height, recognize that a peer may
not be at the tip at the same time we are. We monitor headers/invs
to update the 'peerHeight' variable.
2. Ask for merkle blocks from a peer to the maximum height of that
peer (but not later than what we validated to be true).
This avoids us asking past the remotes tip which they didn't like.
3. Redo the SyncSPVAction to use all this and make it much more
reliable in finding peers to download from and getting all the
changes as fast as possible.
In most cases headers would be automatically downloaded if we didn't
connect to that peer for a while, but that is not a guarentee so lets
make sure we actually start downloading headers from any peer we can :)
We connect to the "first" priority stated segments first, in order to
allow the UX to be made much better since it may take a bit of time to
find peers.
To send out transactions in the p2p net is quite a lot of work,
you need to find multiple peers to send the transaction to. First
you send an INV, then you respond to a getData to actually send
the transaction and last you wait for 'reject' messages that may
indicate that there is something wrong with the transaction.
This introduces the BroadcastTxData class that wraps a transaction
and gets callbacks for sending and for rejects, abstracting away
all the complexity for the user.
The uint256 and CKeyID classes are the same baseclass with template
differences only, which makes them fragile to use for overloading.
As such rename the convenience overload slightly.
Based on the idea that randomly selecting a peer from our database will
prioritize based on the peers punishment score, this sets the punishment
for never connected-to peers at 10 (out of 1000) just to give a minor
benefit to speeding up the meshing.
tomFlowee
TomZ