From 2e972be64082be766e06ea9ef645e1137f8ad50f Mon Sep 17 00:00:00 2001
From: Gav Wood <i@gavwood.com>
Date: Sat, 11 Oct 2014 15:44:24 +0200
Subject: [PATCH] Efforts to make reconnect timing strategy more expansive and
 consistent.

---
 libp2p/Host.cpp    | 39 +++++++++++++++++++++------------------
 libp2p/Host.h      |  5 +++--
 libp2p/Session.cpp | 13 ++++++++-----
 libp2p/Session.h   |  3 ---
 4 files changed, 32 insertions(+), 28 deletions(-)

diff --git a/libp2p/Host.cpp b/libp2p/Host.cpp
index 2c93e64e0..b3b8cdbc1 100644
--- a/libp2p/Host.cpp
+++ b/libp2p/Host.cpp
@@ -506,6 +506,7 @@ void Node::connect(Host* _h)
 		if (ec)
 		{
 			clog(NetConnect) << "Connection refused to node" << id.abridged() << "@" << address << "(" << ec.message() << ")";
+			lastDisconnect = TCPError;
 			_h->m_ready += index;
 		}
 		else
@@ -533,26 +534,33 @@ bool Host::havePeer(NodeId _id) const
 	return !!m_peers.count(_id);
 }
 
-unsigned cumulativeFallback(unsigned _failed, DisconnectReason _r)
+unsigned Node::fallbackSeconds() const
 {
-	switch (_r)
+	switch (lastDisconnect)
 	{
 	case BadProtocol:
-		return 30 * (_failed + 1);
+		return 30 * (failedAttempts + 1);
 	case UselessPeer:
 	case TooManyPeers:
 	case ClientQuit:
-		return 15 * (_failed + 1);
+		return 15 * (failedAttempts + 1);
+	case NoDisconnect:
+		return 0;
 	default:
-		if (_failed < 5)
-			return _failed * 5;
-		else if (_failed < 15)
-			return 25 + (_failed - 5) * 10;
+		if (failedAttempts < 5)
+			return failedAttempts * 5;
+		else if (failedAttempts < 15)
+			return 25 + (failedAttempts - 5) * 10;
 		else
-			return 25 + 100 + (_failed - 15) * 20;
+			return 25 + 100 + (failedAttempts - 15) * 20;
 	}
 }
 
+bool Node::shouldReconnect() const
+{
+	return chrono::system_clock::now() > lastAttempted + chrono::seconds(fallbackSeconds());
+}
+
 void Host::growPeers()
 {
 	RecursiveGuard l(x_peers);
@@ -564,7 +572,7 @@ void Host::growPeers()
 			toTry -= m_private;
 		set<Node> ns;
 		for (auto i: toTry)
-			if (chrono::system_clock::now() > m_nodes[m_nodesList[i]]->lastAttempted + chrono::seconds(cumulativeFallback(m_nodes[m_nodesList[i]]->failedAttempts, m_nodes[m_nodesList[i]]->lastDisconnect)))
+			if (m_nodes[m_nodesList[i]]->shouldReconnect())
 				ns.insert(*m_nodes[m_nodesList[i]]);
 
 		if (ns.size())
@@ -577,18 +585,13 @@ void Host::growPeers()
 		else
 		{
 			ensureAccepting();
-			requestNodes();
+			for (auto const& i: m_peers)
+				if (auto p = i.second.lock())
+					p->ensureNodesRequested();
 		}
 	}
 }
 
-void Host::requestNodes()
-{
-	for (auto const& i: m_peers)
-		if (auto p = i.second.lock())
-			p->ensureNodesRequested();
-}
-
 void Host::prunePeers()
 {
 	RecursiveGuard l(x_peers);
diff --git a/libp2p/Host.h b/libp2p/Host.h
index a7beb8c35..52e4af6be 100644
--- a/libp2p/Host.h
+++ b/libp2p/Host.h
@@ -75,6 +75,9 @@ struct Node
 	int secondsSinceLastConnected() const { return lastConnected == std::chrono::system_clock::time_point() ? -1 : (int)std::chrono::duration_cast<std::chrono::seconds>(std::chrono::system_clock::now() - lastConnected).count(); }
 	int secondsSinceLastAttempted() const { return lastAttempted == std::chrono::system_clock::time_point() ? -1 : (int)std::chrono::duration_cast<std::chrono::seconds>(std::chrono::system_clock::now() - lastAttempted).count(); }
 
+	unsigned fallbackSeconds() const;
+	bool shouldReconnect() const;
+
 	bool isOffline() const { return lastDisconnect == -1 || lastAttempted > lastConnected; }
 	bool operator<(Node const& _n) const
 	{
@@ -200,8 +203,6 @@ private:
 	std::shared_ptr<Node> noteNode(NodeId _id, bi::tcp::endpoint const& _a, Origin _o, bool _ready, NodeId _oldId = h256());
 	Nodes potentialPeers(RangeMask<unsigned> const& _known);
 
-	void requestNodes();
-
 	std::string m_clientVersion;											///< Our version string.
 
 	NetworkPreferences m_netPrefs;											///< Network settings.
diff --git a/libp2p/Session.cpp b/libp2p/Session.cpp
index 7c0d291c4..79b84111a 100644
--- a/libp2p/Session.cpp
+++ b/libp2p/Session.cpp
@@ -249,12 +249,15 @@ bool Session::interpret(RLP const& _r)
 	{
 		string reason = "Unspecified";
 		auto r = (DisconnectReason)_r[1].toInt<int>();
-		if (_r[1].isInt())
+		if (!_r[1].isInt())
+			drop(BadProtocol);
+		else
+		{
 			reason = reasonOf(r);
-
-		clogS(NetMessageSummary) << "Disconnect (reason: " << reason << ")";
-		drop(DisconnectRequested);
-		return true;
+			clogS(NetMessageSummary) << "Disconnect (reason: " << reason << ")";
+			drop(DisconnectRequested);
+		}
+		break;
 	}
 	case PingPacket:
 	{
diff --git a/libp2p/Session.h b/libp2p/Session.h
index 289abca26..f76162cca 100644
--- a/libp2p/Session.h
+++ b/libp2p/Session.h
@@ -93,9 +93,6 @@ private:
 	/// Perform a read on the socket.
 	void doRead();
 
-	/// The
-	void writeImpl(bytes& _buffer);
-
 	/// Perform a single round of the write operation. This could end up calling itself asynchronously.
 	void write();