Remove the custom topN generic function. Use slices.SortedFunc
(creates a sorted copy from an iterator) + slices.DeleteFunc (filters
score <= 0) from the standard library. No custom generics needed.
Replace peerWithStats wrapper, manual slice copying, and protectTopN
closure with a generic topN[T] function that sorts by score and
returns top elements. protectedPeers now works directly with
[]*p2p.Peer slices, building per-category score functions that close
over the stats map.
Compute the protected peer set once in dropRandomPeer via
protectedPeers(), then include protection as a condition in
selectDoNotDrop alongside trusted/static/recent checks. This
eliminates the separate filterProtectedPeers post-pass and the
awkward "all protected → skip" branch.
Rename filterProtectedPeers to protectedPeers, returning
map[*p2p.Peer]bool instead of filtering a slice. The map is
checked directly in selectDoNotDrop via protected[p].
protectTopN used maxPeers (configured capacity) to compute the
number of peers to protect. With small droppable sets this could
protect everyone, permanently disabling churn.
Use len(entries) (current droppable count in each category) instead.
With 20 droppable dialed peers and 10% fraction, 2 are protected.
With 3 droppable peers, 0 are protected — churn is never blocked.
Expand the txtracker package doc to describe the tracking flow
(NotifyReceived → chain head → finalization → peer credit) and its
role as stats provider for the dropper.
Rewrite the dropper struct comment to document the full behavior
including the inclusion-based peer protection: two scoring categories
(total finalized + recent EMA), top 10% per pool, union of protected
sets.
Change the long-term protection category from total inclusions to
total finalized inclusions. Finalized txs are harder to game (require
actual block finality, not just inclusion) and represent confirmed
on-chain value.
The recent-inclusion EMA stays on chain head inclusions for
responsiveness — a peer delivering txs that appear in the latest
blocks gets quick protection without waiting for finalization.
The tracker now checks CurrentFinalBlock() on each chain head event
and credits delivering peers for all newly finalized blocks since
the last check.
The dropper periodically disconnects random peers to create churn.
This was blind to peer quality. Add inclusion-based peer protection
using two categories:
1. Total inclusions: protects peers with the highest cumulative
count of delivered txs that were included on chain
2. Recent inclusions (EMA): protects peers with the best recent
inclusion rate, giving newly productive peers faster protection
Each category independently protects the top 10% of inbound and
top 10% of dialed peers. The union of both sets is protected. Only
peers with positive scores qualify.
The dropper defines its own PeerInclusionStats struct and callback
type (getPeerInclusionStatsFunc) so any stats provider (e.g. a
transaction tracker) can plug in without a package dependency. The
callback is nil by default (protection disabled until wired).
The protectionCategories slice is designed for easy extension —
adding a new category requires only appending a struct with a name,
scoring function, and protection fraction.
As of now, Geth disconnects peers only on protocol error or timeout,
meaning once connection slots are filled, the peerset is largely fixed.
As mentioned in https://github.com/ethereum/go-ethereum/issues/31321,
Geth should occasionally disconnect peers to ensure some churn.
What/when to disconnect could depend on:
- the state of geth (e.g. sync or not)
- current number of peers
- peer level metrics
This PR adds a very slow churn using a random drop.
---------
Signed-off-by: Csaba Kiraly <csaba.kiraly@gmail.com>
Co-authored-by: Felix Lange <fjl@twurst.com>
