In split view situation, the canonical chain may only be served by a
tiny amount of peers, and branches may span long durations. Minority
branches may still have a large weight from attestations and should
be discovered. To assist with that, add a branch discovery module that
assists in such a situation by specifically targeting peers with unknown
histories and downloading from them, in addition to sync manager work
which handles popular branches.
The various `PeerScore` constants are used for both beacon blocks and
LC objects, and will likely also find use for EIP4844 blob sidecars.
Renaming them to use more generically applicable names not referring
to blocks explicitly aymore.
* Add `NoMonitor` flag to stop SyncManager from monitoring sync situation.
* Remove `toleranceValue` and `PeerScoreHeadTooNew`.
Co-authored-by: Etan Kissling <etan@status.im>
* Harden handling of unviable forks
In our current handling of unviable forks, we allow peers to send us
blocks that come from a different fork - this is not necessarily an
error as it can happen naturally, but it does open up the client to a
case where the same unviable fork keeps getting requested - rather than
allowing this to happen, we'll now give these peers a small negative
score - if it keeps happening, we'll disconnect them.
* keep track of unviable forks in quarantine, to avoid filling it with
known junk
* collect peer scores in single module
* descore peers when they send unviable blocks during sync
* don't give score for duplicate blocks
* increase quarantine size to a level that allows finality to happen
under optimal conditions - this helps avoid downloading the same blocks
over and over in case of an unviable fork
* increase initial score for new peers to make room for one more failure
before disconnection
* log and score invalid/unviable blocks in requestmanager too
* avoid ChainDAG dependency in quarantine
* reject gossip blocks with unviable parent
* continue processing unviable sync blocks in order to build unviable
dag
* docs
* Update beacon_chain/consensus_object_pools/block_pools_types.nim
* add unviable queue test
Etan Kissling
Jacek Sieka
tersec
Eugene Kabanov
Miran