Last year we started wrapping the Peer object in a shared pointer,
which is used now in the managers.
This continues the idea by making the PrivacySegment use smart
pointers too and the P2PNetInterface is changed to do the same
for downstream applications.
When the SyncChainAction was written, various interactions we do
today in the ConnectionManager did not happen yet. Features in
Peer didn't exist yet.
This updates the SyncChainAction to take those items into account
and be more responsive and conclue we are 'up to date' faster,
while also leaving behind a better state.
Now we have 3 more logically divided interfaces for the listener
pattern (callbacks).
A P2PNetInterface for peers maintainance.
A DataListenerInterface for the sections getting new data.
And last the new HeaderSyncInterface about the state of the
header-chain (application wide).
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 :)
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 NetworkManager usage was mostly for low connection counts and this
made defaults selection easy.
With more usages it is important to allow the NWM-connection to be more
configurable about memory usage and leaner in general.
This changes the headers-buffers (used to create envelopes) to not be per
connection anymore but per thread using the tread_local keyword.
This changes the ring-buffers to become configurable using
NetworkConnections::setMessageQueueSizes().
Also removing some include statements where they were not really needed
in the P2PNet lib.
We reuse the NetworkManager lower level code in order to connect
to the Bitcoin P2P network.
This implements the basics for anyone wanting to be a player on
this network.
tomFlowee
TomZ