From 3b54b49b0b899c56c25c0691117b529664145a24 Mon Sep 17 00:00:00 2001
From: Arkadiy Paronyan <arkady.paronyan@gmail.com>
Date: Fri, 24 Mar 2017 18:55:57 +0100
Subject: [PATCH] Resilient warp sync (#5018)

---
 sync/src/chain.rs           | 33 +++++++++++++++++++--------------
 sync/src/snapshot.rs        |  5 +++++
 util/network/src/session.rs |  4 ++--
 3 files changed, 26 insertions(+), 16 deletions(-)

diff --git a/sync/src/chain.rs b/sync/src/chain.rs
index 47ddf6ab1..df5f65a86 100644
--- a/sync/src/chain.rs
+++ b/sync/src/chain.rs
@@ -164,8 +164,8 @@ const HEADERS_TIMEOUT_SEC: u64 = 15;
 const BODIES_TIMEOUT_SEC: u64 = 10;
 const RECEIPTS_TIMEOUT_SEC: u64 = 10;
 const FORK_HEADER_TIMEOUT_SEC: u64 = 3;
-const SNAPSHOT_MANIFEST_TIMEOUT_SEC: u64 = 3;
-const SNAPSHOT_DATA_TIMEOUT_SEC: u64 = 60;
+const SNAPSHOT_MANIFEST_TIMEOUT_SEC: u64 = 5;
+const SNAPSHOT_DATA_TIMEOUT_SEC: u64 = 120;
 
 #[derive(Copy, Clone, Eq, PartialEq, Debug)]
 /// Sync state
@@ -463,12 +463,7 @@ impl ChainSync {
 	/// Reset sync. Clear all downloaded data but keep the queue
 	fn reset(&mut self, io: &mut SyncIo) {
 		self.new_blocks.reset();
-		self.snapshot.clear();
 		let chain_info = io.chain().chain_info();
-		if self.state == SyncState::SnapshotData {
-			debug!(target:"sync", "Aborting snapshot restore");
-			io.snapshot_service().abort_restore();
-		}
 		for (_, ref mut p) in &mut self.peers {
 			if p.block_set != Some(BlockSet::OldBlocks) {
 				p.reset_asking();
@@ -487,6 +482,11 @@ impl ChainSync {
 	/// Restart sync
 	pub fn reset_and_continue(&mut self, io: &mut SyncIo) {
 		trace!(target: "sync", "Restarting");
+		if self.state == SyncState::SnapshotData {
+			debug!(target:"sync", "Aborting snapshot restore");
+			io.snapshot_service().abort_restore();
+		}
+		self.snapshot.clear();
 		self.reset(io);
 		self.continue_sync(io);
 	}
@@ -499,7 +499,7 @@ impl ChainSync {
 	}
 
 	fn maybe_start_snapshot_sync(&mut self, io: &mut SyncIo) {
-		if self.state != SyncState::WaitingPeers {
+		if self.state != SyncState::WaitingPeers && self.state != SyncState::Blocks && self.state != SyncState::Waiting {
 			return;
 		}
 		// Make sure the snapshot block is not too far away from best block and network best block and
@@ -531,7 +531,7 @@ impl ChainSync {
 			(best_hash, max_peers, snapshot_peers)
 		};
 
-		let timeout = self.sync_start_time.map_or(false, |t| ((time::precise_time_ns() - t) / 1_000_000_000) > WAIT_PEERS_TIMEOUT_SEC);
+		let timeout = (self.state == SyncState::WaitingPeers) && self.sync_start_time.map_or(false, |t| ((time::precise_time_ns() - t) / 1_000_000_000) > WAIT_PEERS_TIMEOUT_SEC);
 
 		if let (Some(hash), Some(peers)) = (best_hash, best_hash.map_or(None, |h| snapshot_peers.get(&h))) {
 			if max_peers >= SNAPSHOT_MIN_PEERS {
@@ -549,13 +549,18 @@ impl ChainSync {
 	}
 
 	fn start_snapshot_sync(&mut self, io: &mut SyncIo, peers: &[PeerId]) {
-		self.snapshot.clear();
-		for p in peers {
-			if self.peers.get(p).map_or(false, |p| p.asking == PeerAsking::Nothing) {
-				self.request_snapshot_manifest(io, *p);
+		if !self.snapshot.have_manifest() {
+			for p in peers {
+				if self.peers.get(p).map_or(false, |p| p.asking == PeerAsking::Nothing) {
+					self.request_snapshot_manifest(io, *p);
+				}
 			}
+			self.state = SyncState::SnapshotManifest;
+			trace!(target: "sync", "New snapshot sync with {:?}", peers);
+		} else {
+			self.state = SyncState::SnapshotData;
+			trace!(target: "sync", "Resumed snapshot sync with {:?}", peers);
 		}
-		self.state = SyncState::SnapshotManifest;
 	}
 
 	/// Restart sync disregarding the block queue status. May end up re-downloading up to QUEUE_SIZE blocks
diff --git a/sync/src/snapshot.rs b/sync/src/snapshot.rs
index c19860101..94794a4d4 100644
--- a/sync/src/snapshot.rs
+++ b/sync/src/snapshot.rs
@@ -54,6 +54,11 @@ impl Snapshot {
 		self.snapshot_hash = None;
 	}
 
+	/// Check if currently downloading a snapshot.
+	pub fn have_manifest(&self) -> bool {
+		self.snapshot_hash.is_some()
+	}
+
 	/// Reset collection for a manifest RLP
 	pub fn reset_to(&mut self, manifest: &ManifestData, hash: &H256) {
 		self.clear();
diff --git a/util/network/src/session.rs b/util/network/src/session.rs
index 59eac6e5d..8affb4cf7 100644
--- a/util/network/src/session.rs
+++ b/util/network/src/session.rs
@@ -35,8 +35,8 @@ use stats::NetworkStats;
 use time;
 
 // Timeout must be less than (interval - 1).
-const PING_TIMEOUT_SEC: u64 = 15;
-const PING_INTERVAL_SEC: u64 = 30;
+const PING_TIMEOUT_SEC: u64 = 60;
+const PING_INTERVAL_SEC: u64 = 120;
 
 #[derive(Debug, Clone)]
 enum ProtocolState {