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Remove peers with unknown height, lower height or same height and same block signature (unless we don't have their block signature)

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Adapted from code originally written by catbref from before genesis, and essentially prevents syncing backwards. This needs significant testing on testnet.
This commit is contained in:
CalDescent 2022-04-16 11:30:07 +01:00
parent c59869982b
commit 895f02f178
2 changed files with 26 additions and 0 deletions
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23
src/main/java/org/qortal/controller/Controller.java
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@ -655,6 +655,29 @@ public class Controller extends Thread {
return lastMisbehaved != null && lastMisbehaved > NTP.getTime() - MISBEHAVIOUR_COOLOFF;
};
/** True if peer has unknown height, lower height or same height and same block signature (unless we don't have their block signature). */
public static Predicate<Peer> hasShorterBlockchain = peer -> {
BlockData highestBlockData = getInstance().getChainTip();
int ourHeight = highestBlockData.getHeight();
final PeerChainTipData peerChainTipData = peer.getChainTipData();
// Ensure we have chain tip data for this peer
if (peerChainTipData == null)
return true;
// Remove if peer is at a lower height than us
Integer peerHeight = peerChainTipData.getLastHeight();
if (peerHeight == null || peerHeight < ourHeight)
return true;
// Don't remove if peer is on a greater height chain than us, or if we don't have their block signature
if (peerHeight > ourHeight || peerChainTipData.getLastBlockSignature() == null)
return false;
// Remove if signatures match
return Arrays.equals(peerChainTipData.getLastBlockSignature(), highestBlockData.getSignature());
};
public static final Predicate<Peer> hasNoRecentBlock = peer -> {
final Long minLatestBlockTimestamp = getMinimumLatestBlockTimestamp();
final PeerChainTipData peerChainTipData = peer.getChainTipData();

3
src/main/java/org/qortal/controller/Synchronizer.java
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@ -235,6 +235,9 @@ public class Synchronizer extends Thread {
// Disregard peers that are on the same block as last sync attempt and we didn't like their chain
peers.removeIf(Controller.hasInferiorChainTip);
// Remove peers with unknown height, lower height or same height and same block signature (unless we don't have their block signature)
peers.removeIf(Controller.hasShorterBlockchain);
final int peersBeforeComparison = peers.size();
// Request recent block summaries from the remaining peers, and locate our common block with each