What the developer wrote
Authored by Calvin Kim
netsync: add fetchHeaders
fetchHeaders picks a random peer at a higher advertised block and
requests headers from them.
What changed, and why it matters
This commit adds a new internal helper function called fetchHeaders to the Bitcoin network synchronization code. It simply picks a peer that claims to have a higher block and asks that peer for block headers. There is no indication of a bug fix or security patch; it appears to be a normal feature/refactoring addition.
No security action required. Review as part of normal code quality and integration testing.
Security signals we found
No strong security signals were identified.
Evidence from the diff
The diff introduces fetchHeaders() in netsync/manager.go. The function obtains the current best header height, queries peers advertising a higher block, selects one at random, builds a block locator, and sends a getheaders message. It sets headersFirstMode and syncPeer. No existing behavior is removed or altered; this is additive code.
Changed components
netsync/manager.goInspect captured patch +28 / −0
diff --git a/netsync/manager.go b/netsync/manager.go
index 5f40ff8..69bb3f7 100644
--- a/netsync/manager.go
+++ b/netsync/manager.go
@@ -284,6 +284,34 @@ func (sm *SyncManager) isInIBDMode() bool {
return true
}
+// fetchHeaders randomly picks a peer that has a higher advertised header
+// and pushes a get headers message to it.
+func (sm *SyncManager) fetchHeaders() {
+ _, height := sm.chain.BestHeader()
+ higherPeers := sm.fetchHigherPeers(height)
+ if len(higherPeers) == 0 {
+ log.Warnf("No sync peer candidates available")
+ return
+ }
+ bestPeer := higherPeers[rand.Intn(len(higherPeers))]
+
+ locator, err := sm.chain.LatestBlockLocatorByHeader()
+ if err != nil {
+ log.Errorf("Failed to get block locator for the "+
+ "latest block header: %v", err)
+ return
+ }
+
+ log.Infof("Downloading headers for blocks %d to "+
+ "%d from peer %s", height+1,
+ bestPeer.LastBlock(), bestPeer.Addr())
+
+ bestPeer.PushGetHeadersMsg(locator, &zeroHash)
+
+ sm.headersFirstMode = true
+ sm.syncPeer = bestPeer
+}
+
// startSync will choose the best peer among the available candidate peers to
// download/sync the blockchain from. When syncing is already running, it
// simply returns. It also examines the candidates for any which are no longer
Why this scored 15/100
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