From 5d2238d179c0da4f7b88feee263649d0d67453e3 Mon Sep 17 00:00:00 2001
From: Gav Wood <i@gavwood.com>
Date: Fri, 10 Oct 2014 17:03:46 +0200
Subject: [PATCH] Manage dead nodes.

---
 alethzero/MainWin.cpp |  5 +++--
 libp2p/Host.cpp       | 11 ++++-------
 libp2p/Host.h         |  1 +
 libp2p/Session.cpp    | 25 ++++++++++++++++---------
 4 files changed, 24 insertions(+), 18 deletions(-)

diff --git a/alethzero/MainWin.cpp b/alethzero/MainWin.cpp
index 77384d7ea..f55bf2d9f 100644
--- a/alethzero/MainWin.cpp
+++ b/alethzero/MainWin.cpp
@@ -766,10 +766,11 @@ void Main::refreshNetwork()
 	auto ns = web3()->nodes();
 	ui->nodes->clear();
 	for (p2p::Node const& i: ns)
-		ui->nodes->addItem(QString("[%1%3] %2 - ( =%5s | /%4s | %6 | %7x ) - *%8 $%9")
+		if (!i.dead)
+			ui->nodes->addItem(QString("[%1%3] %2 - ( =%5s | /%4s | %6 | %7x ) - *%8 $%9")
 						   .arg(QString::fromStdString(i.id.abridged()))
 						   .arg(QString::fromStdString(toString(i.address)))
-						   .arg(i.id == web3()->id() ? " self" : i.isOffline() ? "" : " PEER")
+						   .arg(i.id == web3()->id() ? " self" : i.isOffline() ? " ripe" : " ----")
 						   .arg(i.secondsSinceLastAttempted())
 						   .arg(i.secondsSinceLastConnected())
 						   .arg(QString::fromStdString(reasonOf(i.lastDisconnect)))
diff --git a/libp2p/Host.cpp b/libp2p/Host.cpp
index 82de1727e..44fa137e5 100644
--- a/libp2p/Host.cpp
+++ b/libp2p/Host.cpp
@@ -354,24 +354,21 @@ shared_ptr<Node> Host::noteNode(NodeId _id, bi::tcp::endpoint const& _a, Origin
 	unsigned i;
 	if (!m_nodes.count(_id))
 	{
-		shared_ptr<Node> old;
 		if (m_nodes.count(_oldId))
 		{
-			old = m_nodes[_oldId];
-			i = old->index;
+			i = m_nodes[_oldId]->index;
 			m_nodes.erase(_oldId);
 			m_nodesList[i] = _id;
-			m_nodes[id()] = make_shared<Node>();
 		}
 		else
 		{
 			i = m_nodesList.size();
 			m_nodesList.push_back(_id);
-			m_nodes[_id] = make_shared<Node>();
 		}
+		m_nodes[_id] = make_shared<Node>();
+		m_nodes[_id]->id = _id;
 		m_nodes[_id]->address = _a;
 		m_nodes[_id]->index = i;
-		m_nodes[_id]->id = _id;
 		m_nodes[_id]->idOrigin = _o;
 	}
 	else
@@ -665,7 +662,7 @@ bytes Host::saveNodes() const
 		for (auto const& i: m_nodes)
 		{
 			Node const& n = *(i.second);
-			if (n.id != id() && !isPrivateAddress(n.address.address()))
+			if (!n.dead && n.id != id() && !isPrivateAddress(n.address.address()))
 			{
 				nodes.appendList(10);
 				if (n.address.address().is_v4())
diff --git a/libp2p/Host.h b/libp2p/Host.h
index 43a5afb25..a7beb8c35 100644
--- a/libp2p/Host.h
+++ b/libp2p/Host.h
@@ -64,6 +64,7 @@ struct Node
 	bi::tcp::endpoint address;						///< As reported from the node itself.
 	int score = 0;									///< All time cumulative.
 	int rating = 0;									///< Trending.
+	bool dead = false;								///< If true, we believe this node is permanently dead - forget all about it.
 	std::chrono::system_clock::time_point lastConnected;
 	std::chrono::system_clock::time_point lastAttempted;
 	unsigned failedAttempts = 0;
diff --git a/libp2p/Session.cpp b/libp2p/Session.cpp
index d647d97dc..3f224a72d 100644
--- a/libp2p/Session.cpp
+++ b/libp2p/Session.cpp
@@ -62,7 +62,7 @@ Session::Session(Host* _s, bi::tcp::socket _socket, std::shared_ptr<Node> const&
 
 Session::~Session()
 {
-	if (id() && !isPermanentProblem(m_node->lastDisconnect))
+	if (id() && (!m_node || (!isPermanentProblem(m_node->lastDisconnect) && !m_node->dead)))
 		m_server->m_ready += m_node->index;
 
 	// Read-chain finished for one reason or another.
@@ -201,14 +201,6 @@ bool Session::interpret(RLP const& _r)
 			return false;
 		}
 
-		if (m_server->havePeer(id))
-		{
-			// Already connected.
-			clogS(NetWarn) << "Already connected to a peer with id" << id.abridged();
-			disconnect(DuplicatePeer);
-			return false;
-		}
-
 		if (m_node && m_node->id != id)
 		{
 			if (m_force || m_node->idOrigin <= Origin::SelfThird)
@@ -220,6 +212,21 @@ bool Session::interpret(RLP const& _r)
 				disconnect(UnexpectedIdentity);
 				return false;
 			}
+
+			if (m_server->havePeer(id))
+			{
+				m_node->dead = true;
+				disconnect(DuplicatePeer);
+				return false;
+			}
+		}
+
+		if (m_server->havePeer(id))
+		{
+			// Already connected.
+			clogS(NetWarn) << "Already connected to a peer with id" << id.abridged();
+			disconnect(DuplicatePeer);
+			return false;
 		}
 
 		if (!id)