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	// Copyright (c) 2009-2010 Satoshi Nakamoto
	// Copyright (c) 2009-2014 The Bitcoin Core developers
	// Distributed under the MIT software license, see the accompanying
	// file COPYING or http://www.opensource.org/licenses/mit-license.php.

	#if defined(HAVE_CONFIG_H)
	#include "config/bitcoin-config.h"
	#endif

	#include "net.h"

	#include "addrman.h"
	#include "chainparams.h"
	#include "clientversion.h"
	#include "crypto/common.h"
	#include "hash.h"
	#include "primitives/transaction.h"
	#include "scheduler.h"
	#include "ui_interface.h"
	#include "utilstrencodings.h"

	#ifdef WIN32
	#include <string.h>
	#else
	#include <fcntl.h>
	#endif

	#ifdef USE_UPNP
	#include <miniupnpc/miniupnpc.h>
	#include <miniupnpc/miniwget.h>
	#include <miniupnpc/upnpcommands.h>
	#include <miniupnpc/upnperrors.h>
	#endif

	#include <boost/filesystem.hpp>
	#include <boost/thread.hpp>

	// Dump addresses to peers.dat every 15 minutes (900s)
	#define DUMP_ADDRESSES_INTERVAL 900

	#if !defined(HAVE_MSG_NOSIGNAL) && !defined(MSG_NOSIGNAL)
	#define MSG_NOSIGNAL 0
	#endif

	// Fix for ancient MinGW versions, that don't have defined these in ws2tcpip.h.
	// Todo: Can be removed when our pull-tester is upgraded to a modern MinGW version.
	#ifdef WIN32
	#ifndef PROTECTION_LEVEL_UNRESTRICTED
	#define PROTECTION_LEVEL_UNRESTRICTED 10
	#endif
	#ifndef IPV6_PROTECTION_LEVEL
	#define IPV6_PROTECTION_LEVEL 23
	#endif
	#endif

	using namespace std;

	namespace {
	const int MAX_OUTBOUND_CONNECTIONS = 8;

	struct ListenSocket {
	SOCKET socket;
	bool whitelisted;

	ListenSocket(SOCKET socket, bool whitelisted) : socket(socket), whitelisted(whitelisted) {}
	};
	}

	//
	// Global state variables
	//
	bool fDiscover = true;
	bool fListen = true;
	uint64_t nLocalServices = NODE_NETWORK;
	CCriticalSection cs_mapLocalHost;
	map<CNetAddr, LocalServiceInfo> mapLocalHost;
	static bool vfReachable[NET_MAX] = {};
	static bool vfLimited[NET_MAX] = {};
	static CNode* pnodeLocalHost = NULL;
	uint64_t nLocalHostNonce = 0;
	static std::vector<ListenSocket> vhListenSocket;
	CAddrMan addrman;
	int nMaxConnections = DEFAULT_MAX_PEER_CONNECTIONS;
	bool fAddressesInitialized = false;
	std::string strSubVersion;

	vector<CNode*> vNodes;
	CCriticalSection cs_vNodes;
	map<CInv, CDataStream> mapRelay;
	deque<pair<int64_t, CInv> > vRelayExpiration;
	CCriticalSection cs_mapRelay;
	limitedmap<CInv, int64_t> mapAlreadyAskedFor(MAX_INV_SZ);

	static deque<string> vOneShots;
	CCriticalSection cs_vOneShots;

	set<CNetAddr> setservAddNodeAddresses;
	CCriticalSection cs_setservAddNodeAddresses;

	vector<std::string> vAddedNodes;
	CCriticalSection cs_vAddedNodes;

	NodeId nLastNodeId = 0;
	CCriticalSection cs_nLastNodeId;

	static CSemaphore *semOutbound = NULL;
	boost::condition_variable messageHandlerCondition;

	// Signals for message handling
	static CNodeSignals g_signals;
	CNodeSignals& GetNodeSignals() { return g_signals; }

	void AddOneShot(const std::string& strDest)
	{
	LOCK(cs_vOneShots);
	vOneShots.push_back(strDest);
	}

	unsigned short GetListenPort()
	{
	return (unsigned short)(GetArg("-port", Params().GetDefaultPort()));
	}

	// find 'best' local address for a particular peer
	bool GetLocal(CService& addr, const CNetAddr *paddrPeer)
	{
	if (!fListen)
	return false;

	int nBestScore = -1;
	int nBestReachability = -1;
	{
	LOCK(cs_mapLocalHost);
	for (map<CNetAddr, LocalServiceInfo>::iterator it = mapLocalHost.begin(); it != mapLocalHost.end(); it++)
	{
	int nScore = (*it).second.nScore;
	int nReachability = (*it).first.GetReachabilityFrom(paddrPeer);
	if (nReachability > nBestReachability \|\| (nReachability == nBestReachability && nScore > nBestScore))
	{
	addr = CService((it).first, (it).second.nPort);
	nBestReachability = nReachability;
	nBestScore = nScore;
	}
	}
	}
	return nBestScore >= 0;
	}

	//! Convert the pnSeeds6 array into usable address objects.
	static std::vector<CAddress> convertSeed6(const std::vector<SeedSpec6> &vSeedsIn)
	{
	// It'll only connect to one or two seed nodes because once it connects,
	// it'll get a pile of addresses with newer timestamps.
	// Seed nodes are given a random 'last seen time' of between one and two
	// weeks ago.
	const int64_t nOneWeek = 72460*60;
	std::vector<CAddress> vSeedsOut;
	vSeedsOut.reserve(vSeedsIn.size());
	for (std::vector<SeedSpec6>::const_iterator i(vSeedsIn.begin()); i != vSeedsIn.end(); ++i)
	{
	struct in6_addr ip;
	memcpy(&ip, i->addr, sizeof(ip));
	CAddress addr(CService(ip, i->port));
	addr.nTime = GetTime() - GetRand(nOneWeek) - nOneWeek;
	vSeedsOut.push_back(addr);
	}
	return vSeedsOut;
	}

	// get best local address for a particular peer as a CAddress
	// Otherwise, return the unroutable 0.0.0.0 but filled in with
	// the normal parameters, since the IP may be changed to a useful
	// one by discovery.
	CAddress GetLocalAddress(const CNetAddr *paddrPeer)
	{
	CAddress ret(CService("0.0.0.0",GetListenPort()),0);
	CService addr;
	if (GetLocal(addr, paddrPeer))
	{
	ret = CAddress(addr);
	}
	ret.nServices = nLocalServices;
	ret.nTime = GetAdjustedTime();
	return ret;
	}

	int GetnScore(const CService& addr)
	{
	LOCK(cs_mapLocalHost);
	if (mapLocalHost.count(addr) == LOCAL_NONE)
	return 0;
	return mapLocalHost[addr].nScore;
	}

	// Is our peer's addrLocal potentially useful as an external IP source?
	bool IsPeerAddrLocalGood(CNode *pnode)
	{
	return fDiscover && pnode->addr.IsRoutable() && pnode->addrLocal.IsRoutable() &&
	!IsLimited(pnode->addrLocal.GetNetwork());
	}

	// pushes our own address to a peer
	void AdvertizeLocal(CNode *pnode)
	{
	if (fListen && pnode->fSuccessfullyConnected)
	{
	CAddress addrLocal = GetLocalAddress(&pnode->addr);
	// If discovery is enabled, sometimes give our peer the address it
	// tells us that it sees us as in case it has a better idea of our
	// address than we do.
	if (IsPeerAddrLocalGood(pnode) && (!addrLocal.IsRoutable() \|\|
	GetRand((GetnScore(addrLocal) > LOCAL_MANUAL) ? 8:2) == 0))
	{
	addrLocal.SetIP(pnode->addrLocal);
	}
	if (addrLocal.IsRoutable())
	{
	pnode->PushAddress(addrLocal);
	}
	}
	}

	void SetReachable(enum Network net, bool fFlag)
	{
	LOCK(cs_mapLocalHost);
	vfReachable[net] = fFlag;
	if (net == NET_IPV6 && fFlag)
	vfReachable[NET_IPV4] = true;
	}

	// learn a new local address
	bool AddLocal(const CService& addr, int nScore)
	{
	if (!addr.IsRoutable())
	return false;

	if (!fDiscover && nScore < LOCAL_MANUAL)
	return false;

	if (IsLimited(addr))
	return false;

	LogPrintf("AddLocal(%s,%i)\n", addr.ToString(), nScore);

	{
	LOCK(cs_mapLocalHost);
	bool fAlready = mapLocalHost.count(addr) > 0;
	LocalServiceInfo &info = mapLocalHost[addr];
	if (!fAlready \|\| nScore >= info.nScore) {
	info.nScore = nScore + (fAlready ? 1 : 0);
	info.nPort = addr.GetPort();
	}
	SetReachable(addr.GetNetwork());
	}

	return true;
	}

	bool AddLocal(const CNetAddr &addr, int nScore)
	{
	return AddLocal(CService(addr, GetListenPort()), nScore);
	}

	/** Make a particular network entirely off-limits (no automatic connects to it) */
	void SetLimited(enum Network net, bool fLimited)
	{
	if (net == NET_UNROUTABLE)
	return;
	LOCK(cs_mapLocalHost);
	vfLimited[net] = fLimited;
	}

	bool IsLimited(enum Network net)
	{
	LOCK(cs_mapLocalHost);
	return vfLimited[net];
	}

	bool IsLimited(const CNetAddr &addr)
	{
	return IsLimited(addr.GetNetwork());
	}

	/** vote for a local address */
	bool SeenLocal(const CService& addr)
	{
	{
	LOCK(cs_mapLocalHost);
	if (mapLocalHost.count(addr) == 0)
	return false;
	mapLocalHost[addr].nScore++;
	}
	return true;
	}


	/** check whether a given address is potentially local */
	bool IsLocal(const CService& addr)
	{
	LOCK(cs_mapLocalHost);
	return mapLocalHost.count(addr) > 0;
	}

	/** check whether a given network is one we can probably connect to */
	bool IsReachable(enum Network net)
	{
	LOCK(cs_mapLocalHost);
	return vfReachable[net] && !vfLimited[net];
	}

	/** check whether a given address is in a network we can probably connect to */
	bool IsReachable(const CNetAddr& addr)
	{
	enum Network net = addr.GetNetwork();
	return IsReachable(net);
	}

	void AddressCurrentlyConnected(const CService& addr)
	{
	addrman.Connected(addr);
	}


	uint64_t CNode::nTotalBytesRecv = 0;
	uint64_t CNode::nTotalBytesSent = 0;
	CCriticalSection CNode::cs_totalBytesRecv;
	CCriticalSection CNode::cs_totalBytesSent;

	CNode* FindNode(const CNetAddr& ip)
	{
	LOCK(cs_vNodes);
	BOOST_FOREACH(CNode* pnode, vNodes)
	if ((CNetAddr)pnode->addr == ip)
	return (pnode);
	return NULL;
	}

	CNode* FindNode(const CSubNet& subNet)
	{
	LOCK(cs_vNodes);
	BOOST_FOREACH(CNode* pnode, vNodes)
	if (subNet.Match((CNetAddr)pnode->addr))
	return (pnode);
	return NULL;
	}

	CNode* FindNode(const std::string& addrName)
	{
	LOCK(cs_vNodes);
	BOOST_FOREACH(CNode* pnode, vNodes)
	if (pnode->addrName == addrName)
	return (pnode);
	return NULL;
	}

	CNode* FindNode(const CService& addr)
	{
	LOCK(cs_vNodes);
	BOOST_FOREACH(CNode* pnode, vNodes)
	if ((CService)pnode->addr == addr)
	return (pnode);
	return NULL;
	}

	CNode* ConnectNode(CAddress addrConnect, const char *pszDest)
	{
	if (pszDest == NULL) {
	if (IsLocal(addrConnect))
	return NULL;

	// Look for an existing connection
	CNode* pnode = FindNode((CService)addrConnect);
	if (pnode)
	{
	pnode->AddRef();
	return pnode;
	}
	}

	/// debug print
	LogPrint("net", "trying connection %s lastseen=%.1fhrs\n",
	pszDest ? pszDest : addrConnect.ToString(),
	pszDest ? 0.0 : (double)(GetAdjustedTime() - addrConnect.nTime)/3600.0);

	// Connect
	SOCKET hSocket;
	bool proxyConnectionFailed = false;
	if (pszDest ? ConnectSocketByName(addrConnect, hSocket, pszDest, Params().GetDefaultPort(), nConnectTimeout, &proxyConnectionFailed) :
	ConnectSocket(addrConnect, hSocket, nConnectTimeout, &proxyConnectionFailed))
	{
	if (!IsSelectableSocket(hSocket)) {
	LogPrintf("Cannot create connection: non-selectable socket created (fd >= FD_SETSIZE ?)\n");
	CloseSocket(hSocket);
	return NULL;
	}

	addrman.Attempt(addrConnect);

	// Add node
	CNode* pnode = new CNode(hSocket, addrConnect, pszDest ? pszDest : "", false);
	pnode->AddRef();

	{
	LOCK(cs_vNodes);
	vNodes.push_back(pnode);
	}

	pnode->nTimeConnected = GetTime();

	return pnode;
	} else if (!proxyConnectionFailed) {
	// If connecting to the node failed, and failure is not caused by a problem connecting to
	// the proxy, mark this as an attempt.
	addrman.Attempt(addrConnect);
	}

	return NULL;
	}

	void CNode::CloseSocketDisconnect()
	{
	fDisconnect = true;
	if (hSocket != INVALID_SOCKET)
	{
	LogPrint("net", "disconnecting peer=%d\n", id);
	CloseSocket(hSocket);
	}

	// in case this fails, we'll empty the recv buffer when the CNode is deleted
	TRY_LOCK(cs_vRecvMsg, lockRecv);
	if (lockRecv)
	vRecvMsg.clear();
	}

	void CNode::PushVersion()
	{
	int nBestHeight = g_signals.GetHeight().get_value_or(0);

	int64_t nTime = (fInbound ? GetAdjustedTime() : GetTime());
	CAddress addrYou = (addr.IsRoutable() && !IsProxy(addr) ? addr : CAddress(CService("0.0.0.0",0)));
	CAddress addrMe = GetLocalAddress(&addr);
	GetRandBytes((unsigned char*)&nLocalHostNonce, sizeof(nLocalHostNonce));
	if (fLogIPs)
	LogPrint("net", "send version message: version %d, blocks=%d, us=%s, them=%s, peer=%d\n", PROTOCOL_VERSION, nBestHeight, addrMe.ToString(), addrYou.ToString(), id);
	else
	LogPrint("net", "send version message: version %d, blocks=%d, us=%s, peer=%d\n", PROTOCOL_VERSION, nBestHeight, addrMe.ToString(), id);
	PushMessage("version", PROTOCOL_VERSION, nLocalServices, nTime, addrYou, addrMe,
	nLocalHostNonce, strSubVersion, nBestHeight, true);
	}





	banmap_t CNode::setBanned;
	CCriticalSection CNode::cs_setBanned;
	bool CNode::setBannedIsDirty;

	void CNode::ClearBanned()
	{
	LOCK(cs_setBanned);
	setBanned.clear();
	setBannedIsDirty = true;
	}

	bool CNode::IsBanned(CNetAddr ip)
	{
	bool fResult = false;
	{
	LOCK(cs_setBanned);
	for (banmap_t::iterator it = setBanned.begin(); it != setBanned.end(); it++)
	{
	CSubNet subNet = (*it).first;
	CBanEntry banEntry = (*it).second;

	if(subNet.Match(ip) && GetTime() < banEntry.nBanUntil)
	fResult = true;
	}
	}
	return fResult;
	}

	bool CNode::IsBanned(CSubNet subnet)
	{
	bool fResult = false;
	{
	LOCK(cs_setBanned);
	banmap_t::iterator i = setBanned.find(subnet);
	if (i != setBanned.end())
	{
	CBanEntry banEntry = (*i).second;
	if (GetTime() < banEntry.nBanUntil)
	fResult = true;
	}
	}
	return fResult;
	}

	void CNode::Ban(const CNetAddr& addr, const BanReason &banReason, int64_t bantimeoffset, bool sinceUnixEpoch) {
	CSubNet subNet(addr);
	Ban(subNet, banReason, bantimeoffset, sinceUnixEpoch);
	}

	void CNode::Ban(const CSubNet& subNet, const BanReason &banReason, int64_t bantimeoffset, bool sinceUnixEpoch) {
	CBanEntry banEntry(GetTime());
	banEntry.banReason = banReason;
	if (bantimeoffset <= 0)
	{
	bantimeoffset = GetArg("-bantime", 606024); // Default 24-hour ban
	sinceUnixEpoch = false;
	}
	banEntry.nBanUntil = (sinceUnixEpoch ? 0 : GetTime() )+bantimeoffset;


	LOCK(cs_setBanned);
	if (setBanned[subNet].nBanUntil < banEntry.nBanUntil)
	setBanned[subNet] = banEntry;

	setBannedIsDirty = true;
	}

	bool CNode::Unban(const CNetAddr &addr) {
	CSubNet subNet(addr);
	return Unban(subNet);
	}

	bool CNode::Unban(const CSubNet &subNet) {
	LOCK(cs_setBanned);
	if (setBanned.erase(subNet))
	{
	setBannedIsDirty = true;
	return true;
	}
	return false;
	}

	void CNode::GetBanned(banmap_t &banMap)
	{
	LOCK(cs_setBanned);
	banMap = setBanned; //create a thread safe copy
	}

	void CNode::SetBanned(const banmap_t &banMap)
	{
	LOCK(cs_setBanned);
	setBanned = banMap;
	setBannedIsDirty = true;
	}

	void CNode::SweepBanned()
	{
	int64_t now = GetTime();

	LOCK(cs_setBanned);
	banmap_t::iterator it = setBanned.begin();
	while(it != setBanned.end())
	{
	CBanEntry banEntry = (*it).second;
	if(now > banEntry.nBanUntil)
	{
	setBanned.erase(it++);
	setBannedIsDirty = true;
	}
	else
	++it;
	}
	}

	bool CNode::BannedSetIsDirty()
	{
	LOCK(cs_setBanned);
	return setBannedIsDirty;
	}

	void CNode::SetBannedSetDirty(bool dirty)
	{
	LOCK(cs_setBanned); //reuse setBanned lock for the isDirty flag
	setBannedIsDirty = dirty;
	}


	std::vector<CSubNet> CNode::vWhitelistedRange;
	CCriticalSection CNode::cs_vWhitelistedRange;

	bool CNode::IsWhitelistedRange(const CNetAddr &addr) {
	LOCK(cs_vWhitelistedRange);
	BOOST_FOREACH(const CSubNet& subnet, vWhitelistedRange) {
	if (subnet.Match(addr))
	return true;
	}
	return false;
	}

	void CNode::AddWhitelistedRange(const CSubNet &subnet) {
	LOCK(cs_vWhitelistedRange);
	vWhitelistedRange.push_back(subnet);
	}

	#undef X
	#define X(name) stats.name = name
	void CNode::copyStats(CNodeStats &stats)
	{
	stats.nodeid = this->GetId();
	X(nServices);
	X(nLastSend);
	X(nLastRecv);
	X(nTimeConnected);
	X(nTimeOffset);
	X(addrName);
	X(nVersion);
	X(cleanSubVer);
	X(fInbound);
	X(nStartingHeight);
	X(nSendBytes);
	X(nRecvBytes);
	X(fWhitelisted);

	// It is common for nodes with good ping times to suddenly become lagged,
	// due to a new block arriving or other large transfer.
	// Merely reporting pingtime might fool the caller into thinking the node was still responsive,
	// since pingtime does not update until the ping is complete, which might take a while.
	// So, if a ping is taking an unusually long time in flight,
	// the caller can immediately detect that this is happening.
	int64_t nPingUsecWait = 0;
	if ((0 != nPingNonceSent) && (0 != nPingUsecStart)) {
	nPingUsecWait = GetTimeMicros() - nPingUsecStart;
	}

	// Raw ping time is in microseconds, but show it to user as whole seconds (Bitcoin users should be well used to small numbers with many decimal places by now :)
	stats.dPingTime = (((double)nPingUsecTime) / 1e6);
	stats.dPingMin = (((double)nMinPingUsecTime) / 1e6);
	stats.dPingWait = (((double)nPingUsecWait) / 1e6);

	// Leave string empty if addrLocal invalid (not filled in yet)
	stats.addrLocal = addrLocal.IsValid() ? addrLocal.ToString() : "";
	}
	#undef X

	// requires LOCK(cs_vRecvMsg)
	bool CNode::ReceiveMsgBytes(const char *pch, unsigned int nBytes)
	{
	while (nBytes > 0) {

	// get current incomplete message, or create a new one
	if (vRecvMsg.empty() \|\|
	vRecvMsg.back().complete())
	vRecvMsg.push_back(CNetMessage(Params().MessageStart(), SER_NETWORK, nRecvVersion));

	CNetMessage& msg = vRecvMsg.back();

	// absorb network data
	int handled;
	if (!msg.in_data)
	handled = msg.readHeader(pch, nBytes);
	else
	handled = msg.readData(pch, nBytes);

	if (handled < 0)
	return false;

	if (msg.in_data && msg.hdr.nMessageSize > MAX_PROTOCOL_MESSAGE_LENGTH) {
	LogPrint("net", "Oversized message from peer=%i, disconnecting\n", GetId());
	return false;
	}

	pch += handled;
	nBytes -= handled;

	if (msg.complete()) {
	msg.nTime = GetTimeMicros();
	messageHandlerCondition.notify_one();
	}
	}

	return true;
	}

	int CNetMessage::readHeader(const char *pch, unsigned int nBytes)
	{
	// copy data to temporary parsing buffer
	unsigned int nRemaining = 24 - nHdrPos;
	unsigned int nCopy = std::min(nRemaining, nBytes);

	memcpy(&hdrbuf[nHdrPos], pch, nCopy);
	nHdrPos += nCopy;

	// if header incomplete, exit
	if (nHdrPos < 24)
	return nCopy;

	// deserialize to CMessageHeader
	try {
	hdrbuf >> hdr;
	}
	catch (const std::exception&) {
	return -1;
	}

	// reject messages larger than MAX_SIZE
	if (hdr.nMessageSize > MAX_SIZE)
	return -1;

	// switch state to reading message data
	in_data = true;

	return nCopy;
	}

	int CNetMessage::readData(const char *pch, unsigned int nBytes)
	{
	unsigned int nRemaining = hdr.nMessageSize - nDataPos;
	unsigned int nCopy = std::min(nRemaining, nBytes);

	if (vRecv.size() < nDataPos + nCopy) {
	// Allocate up to 256 KiB ahead, but never more than the total message size.
	vRecv.resize(std::min(hdr.nMessageSize, nDataPos + nCopy + 256 * 1024));
	}

	memcpy(&vRecv[nDataPos], pch, nCopy);
	nDataPos += nCopy;

	return nCopy;
	}









	// requires LOCK(cs_vSend)
	void SocketSendData(CNode *pnode)
	{
	std::deque<CSerializeData>::iterator it = pnode->vSendMsg.begin();

	while (it != pnode->vSendMsg.end()) {
	const CSerializeData &data = *it;
	assert(data.size() > pnode->nSendOffset);
	int nBytes = send(pnode->hSocket, &data[pnode->nSendOffset], data.size() - pnode->nSendOffset, MSG_NOSIGNAL \| MSG_DONTWAIT);
	if (nBytes > 0) {
	pnode->nLastSend = GetTime();
	pnode->nSendBytes += nBytes;
	pnode->nSendOffset += nBytes;
	pnode->RecordBytesSent(nBytes);
	if (pnode->nSendOffset == data.size()) {
	pnode->nSendOffset = 0;
	pnode->nSendSize -= data.size();
	it++;
	} else {
	// could not send full message; stop sending more
	break;
	}
	} else {
	if (nBytes < 0) {
	// error
	int nErr = WSAGetLastError();
	if (nErr != WSAEWOULDBLOCK && nErr != WSAEMSGSIZE && nErr != WSAEINTR && nErr != WSAEINPROGRESS)
	{
	LogPrintf("socket send error %s\n", NetworkErrorString(nErr));
	pnode->CloseSocketDisconnect();
	}
	}
	// couldn't send anything at all
	break;
	}
	}

	if (it == pnode->vSendMsg.end()) {
	assert(pnode->nSendOffset == 0);
	assert(pnode->nSendSize == 0);
	}
	pnode->vSendMsg.erase(pnode->vSendMsg.begin(), it);
	}

	static list<CNode*> vNodesDisconnected;

	class CNodeRef {
	public:
	CNodeRef(CNode *pnode) : _pnode(pnode) {
	LOCK(cs_vNodes);
	_pnode->AddRef();
	}

	~CNodeRef() {
	LOCK(cs_vNodes);
	_pnode->Release();
	}

	CNode& operator () const {return _pnode;};
	CNode* operator ->() const {return _pnode;};

	CNodeRef& operator =(const CNodeRef& other)
	{
	if (this != &other) {
	LOCK(cs_vNodes);

	_pnode->Release();
	_pnode = other._pnode;
	_pnode->AddRef();
	}
	return *this;
	}

	CNodeRef(const CNodeRef& other):
	_pnode(other._pnode)
	{
	LOCK(cs_vNodes);
	_pnode->AddRef();
	}
	private:
	CNode *_pnode;
	};

	static bool ReverseCompareNodeMinPingTime(const CNodeRef &a, const CNodeRef &b)
	{
	return a->nMinPingUsecTime > b->nMinPingUsecTime;
	}

	static bool ReverseCompareNodeTimeConnected(const CNodeRef &a, const CNodeRef &b)
	{
	return a->nTimeConnected > b->nTimeConnected;
	}

	class CompareNetGroupKeyed
	{
	std::vector<unsigned char> vchSecretKey;
	public:
	CompareNetGroupKeyed()
	{
	vchSecretKey.resize(32, 0);
	GetRandBytes(vchSecretKey.data(), vchSecretKey.size());
	}

	bool operator()(const CNodeRef &a, const CNodeRef &b)
	{
	std::vector<unsigned char> vchGroupA, vchGroupB;
	CSHA256 hashA, hashB;
	std::vector<unsigned char> vchA(32), vchB(32);

	vchGroupA = a->addr.GetGroup();
	vchGroupB = b->addr.GetGroup();

	hashA.Write(begin_ptr(vchGroupA), vchGroupA.size());
	hashB.Write(begin_ptr(vchGroupB), vchGroupB.size());

	hashA.Write(begin_ptr(vchSecretKey), vchSecretKey.size());
	hashB.Write(begin_ptr(vchSecretKey), vchSecretKey.size());

	hashA.Finalize(begin_ptr(vchA));
	hashB.Finalize(begin_ptr(vchB));

	return vchA < vchB;
	}
	};

	static bool AttemptToEvictConnection(bool fPreferNewConnection) {
	std::vector<CNodeRef> vEvictionCandidates;
	{
	LOCK(cs_vNodes);

	BOOST_FOREACH(CNode *node, vNodes) {
	if (node->fWhitelisted)
	continue;
	if (!node->fInbound)
	continue;
	if (node->fDisconnect)
	continue;
	if (node->addr.IsLocal())
	continue;
	vEvictionCandidates.push_back(CNodeRef(node));
	}
	}

	if (vEvictionCandidates.empty()) return false;

	// Protect connections with certain characteristics

	// Deterministically select 4 peers to protect by netgroup.
	// An attacker cannot predict which netgroups will be protected.
	static CompareNetGroupKeyed comparerNetGroupKeyed;
	std::sort(vEvictionCandidates.begin(), vEvictionCandidates.end(), comparerNetGroupKeyed);
	vEvictionCandidates.erase(vEvictionCandidates.end() - std::min(4, static_cast<int>(vEvictionCandidates.size())), vEvictionCandidates.end());

	if (vEvictionCandidates.empty()) return false;

	// Protect the 8 nodes with the best ping times.
	// An attacker cannot manipulate this metric without physically moving nodes closer to the target.
	std::sort(vEvictionCandidates.begin(), vEvictionCandidates.end(), ReverseCompareNodeMinPingTime);
	vEvictionCandidates.erase(vEvictionCandidates.end() - std::min(8, static_cast<int>(vEvictionCandidates.size())), vEvictionCandidates.end());

	if (vEvictionCandidates.empty()) return false;

	// Protect the half of the remaining nodes which have been connected the longest.
	// This replicates the existing implicit behavior.
	std::sort(vEvictionCandidates.begin(), vEvictionCandidates.end(), ReverseCompareNodeTimeConnected);
	vEvictionCandidates.erase(vEvictionCandidates.end() - static_cast<int>(vEvictionCandidates.size() / 2), vEvictionCandidates.end());

	if (vEvictionCandidates.empty()) return false;

	// Identify the network group with the most connections
	std::vector<unsigned char> naMostConnections;
	unsigned int nMostConnections = 0;
	std::map<std::vector<unsigned char>, std::vector<CNodeRef> > mapAddrCounts;
	BOOST_FOREACH(const CNodeRef &node, vEvictionCandidates) {
	mapAddrCounts[node->addr.GetGroup()].push_back(node);

	if (mapAddrCounts[node->addr.GetGroup()].size() > nMostConnections) {
	nMostConnections = mapAddrCounts[node->addr.GetGroup()].size();
	naMostConnections = node->addr.GetGroup();
	}
	}

	// Reduce to the network group with the most connections
	vEvictionCandidates = mapAddrCounts[naMostConnections];

	// Do not disconnect peers if there is only 1 connection from their network group
	if (vEvictionCandidates.size() <= 1)
	// unless we prefer the new connection (for whitelisted peers)
	if (!fPreferNewConnection)
	return false;

	// Disconnect the most recent connection from the network group with the most connections
	std::sort(vEvictionCandidates.begin(), vEvictionCandidates.end(), ReverseCompareNodeTimeConnected);
	vEvictionCandidates[0]->fDisconnect = true;

	return true;
	}

	static void AcceptConnection(const ListenSocket& hListenSocket) {
	struct sockaddr_storage sockaddr;
	socklen_t len = sizeof(sockaddr);
	SOCKET hSocket = accept(hListenSocket.socket, (struct sockaddr*)&sockaddr, &len);
	CAddress addr;
	int nInbound = 0;
	int nMaxInbound = nMaxConnections - MAX_OUTBOUND_CONNECTIONS;

	if (hSocket != INVALID_SOCKET)
	if (!addr.SetSockAddr((const struct sockaddr*)&sockaddr))
	LogPrintf("Warning: Unknown socket family\n");

	bool whitelisted = hListenSocket.whitelisted \|\| CNode::IsWhitelistedRange(addr);
	{
	LOCK(cs_vNodes);
	BOOST_FOREACH(CNode* pnode, vNodes)
	if (pnode->fInbound)
	nInbound++;
	}

	if (hSocket == INVALID_SOCKET)
	{
	int nErr = WSAGetLastError();
	if (nErr != WSAEWOULDBLOCK)
	LogPrintf("socket error accept failed: %s\n", NetworkErrorString(nErr));
	return;
	}

	if (!IsSelectableSocket(hSocket))
	{
	LogPrintf("connection from %s dropped: non-selectable socket\n", addr.ToString());
	CloseSocket(hSocket);
	return;
	}

	if (CNode::IsBanned(addr) && !whitelisted)
	{
	LogPrintf("connection from %s dropped (banned)\n", addr.ToString());
	CloseSocket(hSocket);
	return;
	}

	if (nInbound >= nMaxInbound)
	{
	if (!AttemptToEvictConnection(whitelisted)) {
	// No connection to evict, disconnect the new connection
	LogPrint("net", "failed to find an eviction candidate - connection dropped (full)\n");
	CloseSocket(hSocket);
	return;
	}
	}

	CNode* pnode = new CNode(hSocket, addr, "", true);
	pnode->AddRef();
	pnode->fWhitelisted = whitelisted;

	LogPrint("net", "connection from %s accepted\n", addr.ToString());

	{
	LOCK(cs_vNodes);
	vNodes.push_back(pnode);
	}
	}

	void ThreadSocketHandler()
	{
	unsigned int nPrevNodeCount = 0;
	while (true)
	{
	//
	// Disconnect nodes
	//
	{
	LOCK(cs_vNodes);
	// Disconnect unused nodes
	vector<CNode*> vNodesCopy = vNodes;
	BOOST_FOREACH(CNode* pnode, vNodesCopy)
	{
	if (pnode->fDisconnect \|\|
	(pnode->GetRefCount() <= 0 && pnode->vRecvMsg.empty() && pnode->nSendSize == 0 && pnode->ssSend.empty()))
	{
	// remove from vNodes
	vNodes.erase(remove(vNodes.begin(), vNodes.end(), pnode), vNodes.end());

	// release outbound grant (if any)
	pnode->grantOutbound.Release();

	// close socket and cleanup
	pnode->CloseSocketDisconnect();

	// hold in disconnected pool until all refs are released
	if (pnode->fNetworkNode \|\| pnode->fInbound)
	pnode->Release();
	vNodesDisconnected.push_back(pnode);
	}
	}
	}
	{
	// Delete disconnected nodes
	list<CNode*> vNodesDisconnectedCopy = vNodesDisconnected;
	BOOST_FOREACH(CNode* pnode, vNodesDisconnectedCopy)
	{
	// wait until threads are done using it
	if (pnode->GetRefCount() <= 0)
	{
	bool fDelete = false;
	{
	TRY_LOCK(pnode->cs_vSend, lockSend);
	if (lockSend)
	{
	TRY_LOCK(pnode->cs_vRecvMsg, lockRecv);
	if (lockRecv)
	{
	TRY_LOCK(pnode->cs_inventory, lockInv);
	if (lockInv)
	fDelete = true;
	}
	}
	}
	if (fDelete)
	{
	vNodesDisconnected.remove(pnode);
	delete pnode;
	}
	}
	}
	}
	if(vNodes.size() != nPrevNodeCount) {
	nPrevNodeCount = vNodes.size();
	uiInterface.NotifyNumConnectionsChanged(nPrevNodeCount);
	}

	//
	// Find which sockets have data to receive
	//
	struct timeval timeout;
	timeout.tv_sec = 0;
	timeout.tv_usec = 50000; // frequency to poll pnode->vSend

	fd_set fdsetRecv;
	fd_set fdsetSend;
	fd_set fdsetError;
	FD_ZERO(&fdsetRecv);
	FD_ZERO(&fdsetSend);
	FD_ZERO(&fdsetError);
	SOCKET hSocketMax = 0;
	bool have_fds = false;

	BOOST_FOREACH(const ListenSocket& hListenSocket, vhListenSocket) {
	FD_SET(hListenSocket.socket, &fdsetRecv);
	hSocketMax = max(hSocketMax, hListenSocket.socket);
	have_fds = true;
	}

	{
	LOCK(cs_vNodes);
	BOOST_FOREACH(CNode* pnode, vNodes)
	{
	if (pnode->hSocket == INVALID_SOCKET)
	continue;
	FD_SET(pnode->hSocket, &fdsetError);
	hSocketMax = max(hSocketMax, pnode->hSocket);
	have_fds = true;

	// Implement the following logic:
	// * If there is data to send, select() for sending data. As this only
	// happens when optimistic write failed, we choose to first drain the
	// write buffer in this case before receiving more. This avoids
	// needlessly queueing received data, if the remote peer is not themselves
	// receiving data. This means properly utilizing TCP flow control signalling.
	// * Otherwise, if there is no (complete) message in the receive buffer,
	// or there is space left in the buffer, select() for receiving data.
	// * (if neither of the above applies, there is certainly one message
	// in the receiver buffer ready to be processed).
	// Together, that means that at least one of the following is always possible,
	// so we don't deadlock:
	// * We send some data.
	// * We wait for data to be received (and disconnect after timeout).
	// * We process a message in the buffer (message handler thread).
	{
	TRY_LOCK(pnode->cs_vSend, lockSend);
	if (lockSend && !pnode->vSendMsg.empty()) {
	FD_SET(pnode->hSocket, &fdsetSend);
	continue;
	}
	}
	{
	TRY_LOCK(pnode->cs_vRecvMsg, lockRecv);
	if (lockRecv && (
	pnode->vRecvMsg.empty() \|\| !pnode->vRecvMsg.front().complete() \|\|
	pnode->GetTotalRecvSize() <= ReceiveFloodSize()))
	FD_SET(pnode->hSocket, &fdsetRecv);
	}
	}
	}

	int nSelect = select(have_fds ? hSocketMax + 1 : 0,
	&fdsetRecv, &fdsetSend, &fdsetError, &timeout);
	boost::this_thread::interruption_point();

	if (nSelect == SOCKET_ERROR)
	{
	if (have_fds)
	{
	int nErr = WSAGetLastError();
	LogPrintf("socket select error %s\n", NetworkErrorString(nErr));
	for (unsigned int i = 0; i <= hSocketMax; i++)
	FD_SET(i, &fdsetRecv);
	}
	FD_ZERO(&fdsetSend);
	FD_ZERO(&fdsetError);
	MilliSleep(timeout.tv_usec/1000);
	}

	//
	// Accept new connections
	//
	BOOST_FOREACH(const ListenSocket& hListenSocket, vhListenSocket)
	{
	if (hListenSocket.socket != INVALID_SOCKET && FD_ISSET(hListenSocket.socket, &fdsetRecv))
	{
	AcceptConnection(hListenSocket);
	}
	}

	//
	// Service each socket
	//
	vector<CNode*> vNodesCopy;
	{
	LOCK(cs_vNodes);
	vNodesCopy = vNodes;
	BOOST_FOREACH(CNode* pnode, vNodesCopy)
	pnode->AddRef();
	}
	BOOST_FOREACH(CNode* pnode, vNodesCopy)
	{
	boost::this_thread::interruption_point();

	//
	// Receive
	//
	if (pnode->hSocket == INVALID_SOCKET)
	continue;
	if (FD_ISSET(pnode->hSocket, &fdsetRecv) \|\| FD_ISSET(pnode->hSocket, &fdsetError))
	{
	TRY_LOCK(pnode->cs_vRecvMsg, lockRecv);
	if (lockRecv)
	{
	{
	// typical socket buffer is 8K-64K
	char pchBuf[0x10000];
	int nBytes = recv(pnode->hSocket, pchBuf, sizeof(pchBuf), MSG_DONTWAIT);
	if (nBytes > 0)
	{
	if (!pnode->ReceiveMsgBytes(pchBuf, nBytes))
	pnode->CloseSocketDisconnect();
	pnode->nLastRecv = GetTime();
	pnode->nRecvBytes += nBytes;
	pnode->RecordBytesRecv(nBytes);
	}
	else if (nBytes == 0)
	{
	// socket closed gracefully
	if (!pnode->fDisconnect)
	LogPrint("net", "socket closed\n");
	pnode->CloseSocketDisconnect();
	}
	else if (nBytes < 0)
	{
	// error
	int nErr = WSAGetLastError();
	if (nErr != WSAEWOULDBLOCK && nErr != WSAEMSGSIZE && nErr != WSAEINTR && nErr != WSAEINPROGRESS)
	{
	if (!pnode->fDisconnect)
	LogPrintf("socket recv error %s\n", NetworkErrorString(nErr));
	pnode->CloseSocketDisconnect();
	}
	}
	}
	}
	}

	//
	// Send
	//
	if (pnode->hSocket == INVALID_SOCKET)
	continue;
	if (FD_ISSET(pnode->hSocket, &fdsetSend))
	{
	TRY_LOCK(pnode->cs_vSend, lockSend);
	if (lockSend)
	SocketSendData(pnode);
	}

	//
	// Inactivity checking
	//
	int64_t nTime = GetTime();
	if (nTime - pnode->nTimeConnected > 60)
	{
	if (pnode->nLastRecv == 0 \|\| pnode->nLastSend == 0)
	{
	LogPrint("net", "socket no message in first 60 seconds, %d %d from %d\n", pnode->nLastRecv != 0, pnode->nLastSend != 0, pnode->id);
	pnode->fDisconnect = true;
	}
	else if (nTime - pnode->nLastSend > TIMEOUT_INTERVAL)
	{
	LogPrintf("socket sending timeout: %is\n", nTime - pnode->nLastSend);
	pnode->fDisconnect = true;
	}
	else if (nTime - pnode->nLastRecv > (pnode->nVersion > BIP0031_VERSION ? TIMEOUT_INTERVAL : 90*60))
	{
	LogPrintf("socket receive timeout: %is\n", nTime - pnode->nLastRecv);
	pnode->fDisconnect = true;
	}
	else if (pnode->nPingNonceSent && pnode->nPingUsecStart + TIMEOUT_INTERVAL * 1000000 < GetTimeMicros())
	{
	LogPrintf("ping timeout: %fs\n", 0.000001 * (GetTimeMicros() - pnode->nPingUsecStart));
	pnode->fDisconnect = true;
	}
	}
	}
	{
	LOCK(cs_vNodes);
	BOOST_FOREACH(CNode* pnode, vNodesCopy)
	pnode->Release();
	}
	}
	}









	#ifdef USE_UPNP
	void ThreadMapPort()
	{
	std::string port = strprintf("%u", GetListenPort());
	const char * multicastif = 0;
	const char * minissdpdpath = 0;
	struct UPNPDev * devlist = 0;
	char lanaddr[64];

	#ifndef UPNPDISCOVER_SUCCESS
	/* miniupnpc 1.5 */
	devlist = upnpDiscover(2000, multicastif, minissdpdpath, 0);
	#elif MINIUPNPC_API_VERSION < 14
	/* miniupnpc 1.6 */
	int error = 0;
	devlist = upnpDiscover(2000, multicastif, minissdpdpath, 0, 0, &error);
	#else
	/* miniupnpc 1.9.20150730 */
	int error = 0;
	devlist = upnpDiscover(2000, multicastif, minissdpdpath, 0, 0, 2, &error);
	#endif

	struct UPNPUrls urls;
	struct IGDdatas data;
	int r;

	r = UPNP_GetValidIGD(devlist, &urls, &data, lanaddr, sizeof(lanaddr));
	if (r == 1)
	{
	if (fDiscover) {
	char externalIPAddress[40];
	r = UPNP_GetExternalIPAddress(urls.controlURL, data.first.servicetype, externalIPAddress);
	if(r != UPNPCOMMAND_SUCCESS)
	LogPrintf("UPnP: GetExternalIPAddress() returned %d\n", r);
	else
	{
	if(externalIPAddress[0])
	{
	LogPrintf("UPnP: ExternalIPAddress = %s\n", externalIPAddress);
	AddLocal(CNetAddr(externalIPAddress), LOCAL_UPNP);
	}
	else
	LogPrintf("UPnP: GetExternalIPAddress failed.\n");
	}
	}

	string strDesc = "Bitcoin " + FormatFullVersion();

	try {
	while (true) {
	#ifndef UPNPDISCOVER_SUCCESS
	/* miniupnpc 1.5 */
	r = UPNP_AddPortMapping(urls.controlURL, data.first.servicetype,
	port.c_str(), port.c_str(), lanaddr, strDesc.c_str(), "TCP", 0);
	#else
	/* miniupnpc 1.6 */
	r = UPNP_AddPortMapping(urls.controlURL, data.first.servicetype,
	port.c_str(), port.c_str(), lanaddr, strDesc.c_str(), "TCP", 0, "0");
	#endif

	if(r!=UPNPCOMMAND_SUCCESS)
	LogPrintf("AddPortMapping(%s, %s, %s) failed with code %d (%s)\n",
	port, port, lanaddr, r, strupnperror(r));
	else
	LogPrintf("UPnP Port Mapping successful.\n");;

	MilliSleep(20601000); // Refresh every 20 minutes
	}
	}
	catch (const boost::thread_interrupted&)
	{
	r = UPNP_DeletePortMapping(urls.controlURL, data.first.servicetype, port.c_str(), "TCP", 0);
	LogPrintf("UPNP_DeletePortMapping() returned: %d\n", r);
	freeUPNPDevlist(devlist); devlist = 0;
	FreeUPNPUrls(&urls);
	throw;
	}
	} else {
	LogPrintf("No valid UPnP IGDs found\n");
	freeUPNPDevlist(devlist); devlist = 0;
	if (r != 0)
	FreeUPNPUrls(&urls);
	}
	}

	void MapPort(bool fUseUPnP)
	{
	static boost::thread* upnp_thread = NULL;

	if (fUseUPnP)
	{
	if (upnp_thread) {
	upnp_thread->interrupt();
	upnp_thread->join();
	delete upnp_thread;
	}
	upnp_thread = new boost::thread(boost::bind(&TraceThread<void (*)()>, "upnp", &ThreadMapPort));
	}
	else if (upnp_thread) {
	upnp_thread->interrupt();
	upnp_thread->join();
	delete upnp_thread;
	upnp_thread = NULL;
	}
	}

	#else
	void MapPort(bool)
	{
	// Intentionally left blank.
	}
	#endif






	void ThreadDNSAddressSeed()
	{
	// goal: only query DNS seeds if address need is acute
	if ((addrman.size() > 0) &&
	(!GetBoolArg("-forcednsseed", false))) {
	MilliSleep(11 * 1000);

	LOCK(cs_vNodes);
	if (vNodes.size() >= 2) {
	LogPrintf("P2P peers available. Skipped DNS seeding.\n");
	return;
	}
	}

	const vector<CDNSSeedData> &vSeeds = Params().DNSSeeds();
	int found = 0;

	LogPrintf("Loading addresses from DNS seeds (could take a while)\n");

	BOOST_FOREACH(const CDNSSeedData &seed, vSeeds) {
	if (HaveNameProxy()) {
	AddOneShot(seed.host);
	} else {
	vector<CNetAddr> vIPs;
	vector<CAddress> vAdd;
	if (LookupHost(seed.host.c_str(), vIPs))
	{
	BOOST_FOREACH(const CNetAddr& ip, vIPs)
	{
	int nOneDay = 24*3600;
	CAddress addr = CAddress(CService(ip, Params().GetDefaultPort()));
	addr.nTime = GetTime() - 3nOneDay - GetRand(4nOneDay); // use a random age between 3 and 7 days old
	vAdd.push_back(addr);
	found++;
	}
	}
	addrman.Add(vAdd, CNetAddr(seed.name, true));
	}
	}

	LogPrintf("%d addresses found from DNS seeds\n", found);
	}












	void DumpAddresses()
	{
	int64_t nStart = GetTimeMillis();

	CAddrDB adb;
	adb.Write(addrman);

	LogPrint("net", "Flushed %d addresses to peers.dat %dms\n",
	addrman.size(), GetTimeMillis() - nStart);
	}

	void DumpData()
	{
	DumpAddresses();

	if (CNode::BannedSetIsDirty())
	{
	DumpBanlist();
	CNode::SetBannedSetDirty(false);
	}
	}

	void static ProcessOneShot()
	{
	string strDest;
	{
	LOCK(cs_vOneShots);
	if (vOneShots.empty())
	return;
	strDest = vOneShots.front();
	vOneShots.pop_front();
	}
	CAddress addr;
	CSemaphoreGrant grant(*semOutbound, true);
	if (grant) {
	if (!OpenNetworkConnection(addr, &grant, strDest.c_str(), true))
	AddOneShot(strDest);
	}
	}

	void ThreadOpenConnections()
	{
	// Connect to specific addresses
	if (mapArgs.count("-connect") && mapMultiArgs["-connect"].size() > 0)
	{
	for (int64_t nLoop = 0;; nLoop++)
	{
	ProcessOneShot();
	BOOST_FOREACH(const std::string& strAddr, mapMultiArgs["-connect"])
	{
	CAddress addr;
	OpenNetworkConnection(addr, NULL, strAddr.c_str());
	for (int i = 0; i < 10 && i < nLoop; i++)
	{
	MilliSleep(500);
	}
	}
	MilliSleep(500);
	}
	}

	// Initiate network connections
	int64_t nStart = GetTime();
	while (true)
	{
	ProcessOneShot();

	MilliSleep(500);

	CSemaphoreGrant grant(*semOutbound);
	boost::this_thread::interruption_point();

	// Add seed nodes if DNS seeds are all down (an infrastructure attack?).
	if (addrman.size() == 0 && (GetTime() - nStart > 60)) {
	static bool done = false;
	if (!done) {
	LogPrintf("Adding fixed seed nodes as DNS doesn't seem to be available.\n");
	addrman.Add(convertSeed6(Params().FixedSeeds()), CNetAddr("127.0.0.1"));
	done = true;
	}
	}

	//
	// Choose an address to connect to based on most recently seen
	//
	CAddress addrConnect;

	// Only connect out to one peer per network group (/16 for IPv4).
	// Do this here so we don't have to critsect vNodes inside mapAddresses critsect.
	int nOutbound = 0;
	set<vector<unsigned char> > setConnected;
	{
	LOCK(cs_vNodes);
	BOOST_FOREACH(CNode* pnode, vNodes) {
	if (!pnode->fInbound) {
	setConnected.insert(pnode->addr.GetGroup());
	nOutbound++;
	}
	}
	}

	int64_t nANow = GetAdjustedTime();

	int nTries = 0;
	while (true)
	{
	CAddrInfo addr = addrman.Select();

	// if we selected an invalid address, restart
	if (!addr.IsValid() \|\| setConnected.count(addr.GetGroup()) \|\| IsLocal(addr))
	break;

	// If we didn't find an appropriate destination after trying 100 addresses fetched from addrman,
	// stop this loop, and let the outer loop run again (which sleeps, adds seed nodes, recalculates
	// already-connected network ranges, ...) before trying new addrman addresses.
	nTries++;
	if (nTries > 100)
	break;

	if (IsLimited(addr))
	continue;

	// only consider very recently tried nodes after 30 failed attempts
	if (nANow - addr.nLastTry < 600 && nTries < 30)
	continue;

	// do not allow non-default ports, unless after 50 invalid addresses selected already
	if (addr.GetPort() != Params().GetDefaultPort() && nTries < 50)
	continue;

	addrConnect = addr;
	break;
	}

	if (addrConnect.IsValid())
	OpenNetworkConnection(addrConnect, &grant);
	}
	}

	void ThreadOpenAddedConnections()
	{
	{
	LOCK(cs_vAddedNodes);
	vAddedNodes = mapMultiArgs["-addnode"];
	}

	if (HaveNameProxy()) {
	while(true) {
	list<string> lAddresses(0);
	{
	LOCK(cs_vAddedNodes);
	BOOST_FOREACH(const std::string& strAddNode, vAddedNodes)
	lAddresses.push_back(strAddNode);
	}
	BOOST_FOREACH(const std::string& strAddNode, lAddresses) {
	CAddress addr;
	CSemaphoreGrant grant(*semOutbound);
	OpenNetworkConnection(addr, &grant, strAddNode.c_str());
	MilliSleep(500);
	}
	MilliSleep(120000); // Retry every 2 minutes
	}
	}

	for (unsigned int i = 0; true; i++)
	{
	list<string> lAddresses(0);
	{
	LOCK(cs_vAddedNodes);
	BOOST_FOREACH(const std::string& strAddNode, vAddedNodes)
	lAddresses.push_back(strAddNode);
	}

	list<vector<CService> > lservAddressesToAdd(0);
	BOOST_FOREACH(const std::string& strAddNode, lAddresses) {
	vector<CService> vservNode(0);
	if(Lookup(strAddNode.c_str(), vservNode, Params().GetDefaultPort(), fNameLookup, 0))
	{
	lservAddressesToAdd.push_back(vservNode);
	{
	LOCK(cs_setservAddNodeAddresses);
	BOOST_FOREACH(const CService& serv, vservNode)
	setservAddNodeAddresses.insert(serv);
	}
	}
	}
	// Attempt to connect to each IP for each addnode entry until at least one is successful per addnode entry
	// (keeping in mind that addnode entries can have many IPs if fNameLookup)
	{
	LOCK(cs_vNodes);
	BOOST_FOREACH(CNode* pnode, vNodes)
	for (list<vector<CService> >::iterator it = lservAddressesToAdd.begin(); it != lservAddressesToAdd.end(); it++)
	BOOST_FOREACH(const CService& addrNode, *(it))
	if (pnode->addr == addrNode)
	{
	it = lservAddressesToAdd.erase(it);
	it--;
	break;
	}
	}
	BOOST_FOREACH(vector<CService>& vserv, lservAddressesToAdd)
	{
	CSemaphoreGrant grant(*semOutbound);
	OpenNetworkConnection(CAddress(vserv[i % vserv.size()]), &grant);
	MilliSleep(500);
	}
	MilliSleep(120000); // Retry every 2 minutes
	}
	}

	// if successful, this moves the passed grant to the constructed node
	bool OpenNetworkConnection(const CAddress& addrConnect, CSemaphoreGrant grantOutbound, const char pszDest, bool fOneShot)
	{
	//
	// Initiate outbound network connection
	//
	boost::this_thread::interruption_point();
	if (!pszDest) {
	if (IsLocal(addrConnect) \|\|
	FindNode((CNetAddr)addrConnect) \|\| CNode::IsBanned(addrConnect) \|\|
	FindNode(addrConnect.ToStringIPPort()))
	return false;
	} else if (FindNode(std::string(pszDest)))
	return false;

	CNode* pnode = ConnectNode(addrConnect, pszDest);
	boost::this_thread::interruption_point();

	if (!pnode)
	return false;
	if (grantOutbound)
	grantOutbound->MoveTo(pnode->grantOutbound);
	pnode->fNetworkNode = true;
	if (fOneShot)
	pnode->fOneShot = true;

	return true;
	}


	void ThreadMessageHandler()
	{
	boost::mutex condition_mutex;
	boost::unique_lock<boost::mutex> lock(condition_mutex);

	SetThreadPriority(THREAD_PRIORITY_BELOW_NORMAL);
	while (true)
	{
	vector<CNode*> vNodesCopy;
	{
	LOCK(cs_vNodes);
	vNodesCopy = vNodes;
	BOOST_FOREACH(CNode* pnode, vNodesCopy) {
	pnode->AddRef();
	}
	}

	// Poll the connected nodes for messages
	CNode* pnodeTrickle = NULL;
	if (!vNodesCopy.empty())
	pnodeTrickle = vNodesCopy[GetRand(vNodesCopy.size())];

	bool fSleep = true;

	BOOST_FOREACH(CNode* pnode, vNodesCopy)
	{
	if (pnode->fDisconnect)
	continue;

	// Receive messages
	{
	TRY_LOCK(pnode->cs_vRecvMsg, lockRecv);
	if (lockRecv)
	{
	if (!g_signals.ProcessMessages(pnode))
	pnode->CloseSocketDisconnect();

	if (pnode->nSendSize < SendBufferSize())
	{
	if (!pnode->vRecvGetData.empty() \|\| (!pnode->vRecvMsg.empty() && pnode->vRecvMsg[0].complete()))
	{
	fSleep = false;
	}
	}
	}
	}
	boost::this_thread::interruption_point();

	// Send messages
	{
	TRY_LOCK(pnode->cs_vSend, lockSend);
	if (lockSend)
	g_signals.SendMessages(pnode, pnode == pnodeTrickle \|\| pnode->fWhitelisted);
	}
	boost::this_thread::interruption_point();
	}

	{
	LOCK(cs_vNodes);
	BOOST_FOREACH(CNode* pnode, vNodesCopy)
	pnode->Release();
	}

	if (fSleep)
	messageHandlerCondition.timed_wait(lock, boost::posix_time::microsec_clock::universal_time() + boost::posix_time::milliseconds(100));
	}
	}






	bool BindListenPort(const CService &addrBind, string& strError, bool fWhitelisted)
	{
	strError = "";
	int nOne = 1;

	// Create socket for listening for incoming connections
	struct sockaddr_storage sockaddr;
	socklen_t len = sizeof(sockaddr);
	if (!addrBind.GetSockAddr((struct sockaddr*)&sockaddr, &len))
	{
	strError = strprintf("Error: Bind address family for %s not supported", addrBind.ToString());
	LogPrintf("%s\n", strError);
	return false;
	}

	SOCKET hListenSocket = socket(((struct sockaddr*)&sockaddr)->sa_family, SOCK_STREAM, IPPROTO_TCP);
	if (hListenSocket == INVALID_SOCKET)
	{
	strError = strprintf("Error: Couldn't open socket for incoming connections (socket returned error %s)", NetworkErrorString(WSAGetLastError()));
	LogPrintf("%s\n", strError);
	return false;
	}
	if (!IsSelectableSocket(hListenSocket))
	{
	strError = "Error: Couldn't create a listenable socket for incoming connections";
	LogPrintf("%s\n", strError);
	return false;
	}


	#ifndef WIN32
	#ifdef SO_NOSIGPIPE
	// Different way of disabling SIGPIPE on BSD
	setsockopt(hListenSocket, SOL_SOCKET, SO_NOSIGPIPE, (void*)&nOne, sizeof(int));
	#endif
	// Allow binding if the port is still in TIME_WAIT state after
	// the program was closed and restarted.
	setsockopt(hListenSocket, SOL_SOCKET, SO_REUSEADDR, (void*)&nOne, sizeof(int));
	#else
	setsockopt(hListenSocket, SOL_SOCKET, SO_REUSEADDR, (const char*)&nOne, sizeof(int));
	#endif

	// Set to non-blocking, incoming connections will also inherit this
	if (!SetSocketNonBlocking(hListenSocket, true)) {
	strError = strprintf("BindListenPort: Setting listening socket to non-blocking failed, error %s\n", NetworkErrorString(WSAGetLastError()));
	LogPrintf("%s\n", strError);
	return false;
	}

	// some systems don't have IPV6_V6ONLY but are always v6only; others do have the option
	// and enable it by default or not. Try to enable it, if possible.
	if (addrBind.IsIPv6()) {
	#ifdef IPV6_V6ONLY
	#ifdef WIN32
	setsockopt(hListenSocket, IPPROTO_IPV6, IPV6_V6ONLY, (const char*)&nOne, sizeof(int));
	#else
	setsockopt(hListenSocket, IPPROTO_IPV6, IPV6_V6ONLY, (void*)&nOne, sizeof(int));
	#endif
	#endif
	#ifdef WIN32
	int nProtLevel = PROTECTION_LEVEL_UNRESTRICTED;
	setsockopt(hListenSocket, IPPROTO_IPV6, IPV6_PROTECTION_LEVEL, (const char*)&nProtLevel, sizeof(int));
	#endif
	}

	if (::bind(hListenSocket, (struct sockaddr*)&sockaddr, len) == SOCKET_ERROR)
	{
	int nErr = WSAGetLastError();
	if (nErr == WSAEADDRINUSE)
	strError = strprintf(_("Unable to bind to %s on this computer. Bitcoin Core is probably already running."), addrBind.ToString());
	else
	strError = strprintf(_("Unable to bind to %s on this computer (bind returned error %s)"), addrBind.ToString(), NetworkErrorString(nErr));
	LogPrintf("%s\n", strError);
	CloseSocket(hListenSocket);
	return false;
	}
	LogPrintf("Bound to %s\n", addrBind.ToString());

	// Listen for incoming connections
	if (listen(hListenSocket, SOMAXCONN) == SOCKET_ERROR)
	{
	strError = strprintf(_("Error: Listening for incoming connections failed (listen returned error %s)"), NetworkErrorString(WSAGetLastError()));
	LogPrintf("%s\n", strError);
	CloseSocket(hListenSocket);
	return false;
	}

	vhListenSocket.push_back(ListenSocket(hListenSocket, fWhitelisted));

	if (addrBind.IsRoutable() && fDiscover && !fWhitelisted)
	AddLocal(addrBind, LOCAL_BIND);

	return true;
	}

	void static Discover(boost::thread_group& threadGroup)
	{
	if (!fDiscover)
	return;

	#ifdef WIN32
	// Get local host IP
	char pszHostName[256] = "";
	if (gethostname(pszHostName, sizeof(pszHostName)) != SOCKET_ERROR)
	{
	vector<CNetAddr> vaddr;
	if (LookupHost(pszHostName, vaddr))
	{
	BOOST_FOREACH (const CNetAddr &addr, vaddr)
	{
	if (AddLocal(addr, LOCAL_IF))
	LogPrintf("%s: %s - %s\n", __func__, pszHostName, addr.ToString());
	}
	}
	}
	#else
	// Get local host ip
	struct ifaddrs* myaddrs;
	if (getifaddrs(&myaddrs) == 0)
	{
	for (struct ifaddrs* ifa = myaddrs; ifa != NULL; ifa = ifa->ifa_next)
	{
	if (ifa->ifa_addr == NULL) continue;
	if ((ifa->ifa_flags & IFF_UP) == 0) continue;
	if (strcmp(ifa->ifa_name, "lo") == 0) continue;
	if (strcmp(ifa->ifa_name, "lo0") == 0) continue;
	if (ifa->ifa_addr->sa_family == AF_INET)
	{
	struct sockaddr_in* s4 = (struct sockaddr_in*)(ifa->ifa_addr);
	CNetAddr addr(s4->sin_addr);
	if (AddLocal(addr, LOCAL_IF))
	LogPrintf("%s: IPv4 %s: %s\n", __func__, ifa->ifa_name, addr.ToString());
	}
	else if (ifa->ifa_addr->sa_family == AF_INET6)
	{
	struct sockaddr_in6* s6 = (struct sockaddr_in6*)(ifa->ifa_addr);
	CNetAddr addr(s6->sin6_addr);
	if (AddLocal(addr, LOCAL_IF))
	LogPrintf("%s: IPv6 %s: %s\n", __func__, ifa->ifa_name, addr.ToString());
	}
	}
	freeifaddrs(myaddrs);
	}
	#endif
	}

	void StartNode(boost::thread_group& threadGroup, CScheduler& scheduler)
	{
	uiInterface.InitMessage(_("Loading addresses..."));
	// Load addresses for peers.dat
	int64_t nStart = GetTimeMillis();
	{
	CAddrDB adb;
	if (!adb.Read(addrman))
	LogPrintf("Invalid or missing peers.dat; recreating\n");
	}

	//try to read stored banlist
	CBanDB bandb;
	banmap_t banmap;
	if (!bandb.Read(banmap))
	LogPrintf("Invalid or missing banlist.dat; recreating\n");

	CNode::SetBanned(banmap); //thread save setter
	CNode::SetBannedSetDirty(false); //no need to write down just read or nonexistent data
	CNode::SweepBanned(); //sweap out unused entries

	LogPrintf("Loaded %i addresses from peers.dat %dms\n",
	addrman.size(), GetTimeMillis() - nStart);
	fAddressesInitialized = true;

	if (semOutbound == NULL) {
	// initialize semaphore
	int nMaxOutbound = min(MAX_OUTBOUND_CONNECTIONS, nMaxConnections);
	semOutbound = new CSemaphore(nMaxOutbound);
	}

	if (pnodeLocalHost == NULL)
	pnodeLocalHost = new CNode(INVALID_SOCKET, CAddress(CService("127.0.0.1", 0), nLocalServices));

	Discover(threadGroup);

	//
	// Start threads
	//

	if (!GetBoolArg("-dnsseed", true))
	LogPrintf("DNS seeding disabled\n");
	else
	threadGroup.create_thread(boost::bind(&TraceThread<void (*)()>, "dnsseed", &ThreadDNSAddressSeed));

	// Map ports with UPnP
	MapPort(GetBoolArg("-upnp", DEFAULT_UPNP));

	// Send and receive from sockets, accept connections
	threadGroup.create_thread(boost::bind(&TraceThread<void (*)()>, "net", &ThreadSocketHandler));

	// Initiate outbound connections from -addnode
	threadGroup.create_thread(boost::bind(&TraceThread<void (*)()>, "addcon", &ThreadOpenAddedConnections));

	// Initiate outbound connections
	threadGroup.create_thread(boost::bind(&TraceThread<void (*)()>, "opencon", &ThreadOpenConnections));

	// Process messages
	threadGroup.create_thread(boost::bind(&TraceThread<void (*)()>, "msghand", &ThreadMessageHandler));

	// Dump network addresses
	scheduler.scheduleEvery(&DumpData, DUMP_ADDRESSES_INTERVAL);
	}

	bool StopNode()
	{
	LogPrintf("StopNode()\n");
	MapPort(false);
	if (semOutbound)
	for (int i=0; i<MAX_OUTBOUND_CONNECTIONS; i++)
	semOutbound->post();

	if (fAddressesInitialized)
	{
	DumpData();
	fAddressesInitialized = false;
	}

	return true;
	}

	class CNetCleanup
	{
	public:
	CNetCleanup() {}

	~CNetCleanup()
	{
	// Close sockets
	BOOST_FOREACH(CNode* pnode, vNodes)
	if (pnode->hSocket != INVALID_SOCKET)
	CloseSocket(pnode->hSocket);
	BOOST_FOREACH(ListenSocket& hListenSocket, vhListenSocket)
	if (hListenSocket.socket != INVALID_SOCKET)
	if (!CloseSocket(hListenSocket.socket))
	LogPrintf("CloseSocket(hListenSocket) failed with error %s\n", NetworkErrorString(WSAGetLastError()));

	// clean up some globals (to help leak detection)
	BOOST_FOREACH(CNode *pnode, vNodes)
	delete pnode;
	BOOST_FOREACH(CNode *pnode, vNodesDisconnected)
	delete pnode;
	vNodes.clear();
	vNodesDisconnected.clear();
	vhListenSocket.clear();
	delete semOutbound;
	semOutbound = NULL;
	delete pnodeLocalHost;
	pnodeLocalHost = NULL;

	#ifdef WIN32
	// Shutdown Windows Sockets
	WSACleanup();
	#endif
	}
	}
	instance_of_cnetcleanup;







	void RelayTransaction(const CTransaction& tx)
	{
	CDataStream ss(SER_NETWORK, PROTOCOL_VERSION);
	ss.reserve(10000);
	ss << tx;
	RelayTransaction(tx, ss);
	}

	void RelayTransaction(const CTransaction& tx, const CDataStream& ss)
	{
	CInv inv(MSG_TX, tx.GetHash());
	{
	LOCK(cs_mapRelay);
	// Expire old relay messages
	while (!vRelayExpiration.empty() && vRelayExpiration.front().first < GetTime())
	{
	mapRelay.erase(vRelayExpiration.front().second);
	vRelayExpiration.pop_front();
	}

	// Save original serialized message so newer versions are preserved
	mapRelay.insert(std::make_pair(inv, ss));
	vRelayExpiration.push_back(std::make_pair(GetTime() + 15 * 60, inv));
	}
	LOCK(cs_vNodes);
	BOOST_FOREACH(CNode* pnode, vNodes)
	{
	if(!pnode->fRelayTxes)
	continue;
	LOCK(pnode->cs_filter);
	if (pnode->pfilter)
	{
	if (pnode->pfilter->IsRelevantAndUpdate(tx))
	pnode->PushInventory(inv);
	} else
	pnode->PushInventory(inv);
	}
	}

	void CNode::RecordBytesRecv(uint64_t bytes)
	{
	LOCK(cs_totalBytesRecv);
	nTotalBytesRecv += bytes;
	}

	void CNode::RecordBytesSent(uint64_t bytes)
	{
	LOCK(cs_totalBytesSent);
	nTotalBytesSent += bytes;
	}

	uint64_t CNode::GetTotalBytesRecv()
	{
	LOCK(cs_totalBytesRecv);
	return nTotalBytesRecv;
	}

	uint64_t CNode::GetTotalBytesSent()
	{
	LOCK(cs_totalBytesSent);
	return nTotalBytesSent;
	}

	void CNode::Fuzz(int nChance)
	{
	if (!fSuccessfullyConnected) return; // Don't fuzz initial handshake
	if (GetRand(nChance) != 0) return; // Fuzz 1 of every nChance messages

	switch (GetRand(3))
	{
	case 0:
	// xor a random byte with a random value:
	if (!ssSend.empty()) {
	CDataStream::size_type pos = GetRand(ssSend.size());
	ssSend[pos] ^= (unsigned char)(GetRand(256));
	}
	break;
	case 1:
	// delete a random byte:
	if (!ssSend.empty()) {
	CDataStream::size_type pos = GetRand(ssSend.size());
	ssSend.erase(ssSend.begin()+pos);
	}
	break;
	case 2:
	// insert a random byte at a random position
	{
	CDataStream::size_type pos = GetRand(ssSend.size());
	char ch = (char)GetRand(256);
	ssSend.insert(ssSend.begin()+pos, ch);
	}
	break;
	}
	// Chance of more than one change half the time:
	// (more changes exponentially less likely):
	Fuzz(2);
	}

	//
	// CAddrDB
	//

	CAddrDB::CAddrDB()
	{
	pathAddr = GetDataDir() / "peers.dat";
	}

	bool CAddrDB::Write(const CAddrMan& addr)
	{
	// Generate random temporary filename
	unsigned short randv = 0;
	GetRandBytes((unsigned char*)&randv, sizeof(randv));
	std::string tmpfn = strprintf("peers.dat.%04x", randv);

	// serialize addresses, checksum data up to that point, then append csum
	CDataStream ssPeers(SER_DISK, CLIENT_VERSION);
	ssPeers << FLATDATA(Params().MessageStart());
	ssPeers << addr;
	uint256 hash = Hash(ssPeers.begin(), ssPeers.end());
	ssPeers << hash;

	// open temp output file, and associate with CAutoFile
	boost::filesystem::path pathTmp = GetDataDir() / tmpfn;
	FILE *file = fopen(pathTmp.string().c_str(), "wb");
	CAutoFile fileout(file, SER_DISK, CLIENT_VERSION);
	if (fileout.IsNull())
	return error("%s: Failed to open file %s", __func__, pathTmp.string());

	// Write and commit header, data
	try {
	fileout << ssPeers;
	}
	catch (const std::exception& e) {
	return error("%s: Serialize or I/O error - %s", __func__, e.what());
	}
	FileCommit(fileout.Get());
	fileout.fclose();

	// replace existing peers.dat, if any, with new peers.dat.XXXX
	if (!RenameOver(pathTmp, pathAddr))
	return error("%s: Rename-into-place failed", __func__);

	return true;
	}

	bool CAddrDB::Read(CAddrMan& addr)
	{
	// open input file, and associate with CAutoFile
	FILE *file = fopen(pathAddr.string().c_str(), "rb");
	CAutoFile filein(file, SER_DISK, CLIENT_VERSION);
	if (filein.IsNull())
	return error("%s: Failed to open file %s", __func__, pathAddr.string());

	// use file size to size memory buffer
	uint64_t fileSize = boost::filesystem::file_size(pathAddr);
	uint64_t dataSize = 0;
	// Don't try to resize to a negative number if file is small
	if (fileSize >= sizeof(uint256))
	dataSize = fileSize - sizeof(uint256);
	vector<unsigned char> vchData;
	vchData.resize(dataSize);
	uint256 hashIn;

	// read data and checksum from file
	try {
	filein.read((char *)&vchData[0], dataSize);
	filein >> hashIn;
	}
	catch (const std::exception& e) {
	return error("%s: Deserialize or I/O error - %s", __func__, e.what());
	}
	filein.fclose();

	CDataStream ssPeers(vchData, SER_DISK, CLIENT_VERSION);

	// verify stored checksum matches input data
	uint256 hashTmp = Hash(ssPeers.begin(), ssPeers.end());
	if (hashIn != hashTmp)
	return error("%s: Checksum mismatch, data corrupted", __func__);

	unsigned char pchMsgTmp[4];
	try {
	// de-serialize file header (network specific magic number) and ..
	ssPeers >> FLATDATA(pchMsgTmp);

	// ... verify the network matches ours
	if (memcmp(pchMsgTmp, Params().MessageStart(), sizeof(pchMsgTmp)))
	return error("%s: Invalid network magic number", __func__);

	// de-serialize address data into one CAddrMan object
	ssPeers >> addr;
	}
	catch (const std::exception& e) {
	return error("%s: Deserialize or I/O error - %s", __func__, e.what());
	}

	return true;
	}

	unsigned int ReceiveFloodSize() { return 1000GetArg("-maxreceivebuffer", 51000); }
	unsigned int SendBufferSize() { return 1000GetArg("-maxsendbuffer", 11000); }

	CNode::CNode(SOCKET hSocketIn, const CAddress& addrIn, const std::string& addrNameIn, bool fInboundIn) :
	ssSend(SER_NETWORK, INIT_PROTO_VERSION),
	addrKnown(5000, 0.001),
	setInventoryKnown(SendBufferSize() / 1000)
	{
	nServices = 0;
	hSocket = hSocketIn;
	nRecvVersion = INIT_PROTO_VERSION;
	nLastSend = 0;
	nLastRecv = 0;
	nSendBytes = 0;
	nRecvBytes = 0;
	nTimeConnected = GetTime();
	nTimeOffset = 0;
	addr = addrIn;
	addrName = addrNameIn == "" ? addr.ToStringIPPort() : addrNameIn;
	nVersion = 0;
	strSubVer = "";
	fWhitelisted = false;
	fOneShot = false;
	fClient = false; // set by version message
	fInbound = fInboundIn;
	fNetworkNode = false;
	fSuccessfullyConnected = false;
	fDisconnect = false;
	nRefCount = 0;
	nSendSize = 0;
	nSendOffset = 0;
	hashContinue = uint256();
	nStartingHeight = -1;
	fGetAddr = false;
	fRelayTxes = false;
	pfilter = new CBloomFilter();
	nPingNonceSent = 0;
	nPingUsecStart = 0;
	nPingUsecTime = 0;
	fPingQueued = false;
	nMinPingUsecTime = std::numeric_limits<int64_t>::max();

	{
	LOCK(cs_nLastNodeId);
	id = nLastNodeId++;
	}

	if (fLogIPs)
	LogPrint("net", "Added connection to %s peer=%d\n", addrName, id);
	else
	LogPrint("net", "Added connection peer=%d\n", id);

	// Be shy and don't send version until we hear
	if (hSocket != INVALID_SOCKET && !fInbound)
	PushVersion();

	GetNodeSignals().InitializeNode(GetId(), this);
	}

	CNode::~CNode()
	{
	CloseSocket(hSocket);

	if (pfilter)
	delete pfilter;

	GetNodeSignals().FinalizeNode(GetId());
	}

	void CNode::AskFor(const CInv& inv)
	{
	if (mapAskFor.size() > MAPASKFOR_MAX_SZ)
	return;
	// We're using mapAskFor as a priority queue,
	// the key is the earliest time the request can be sent
	int64_t nRequestTime;
	limitedmap<CInv, int64_t>::const_iterator it = mapAlreadyAskedFor.find(inv);
	if (it != mapAlreadyAskedFor.end())
	nRequestTime = it->second;
	else
	nRequestTime = 0;
	LogPrint("net", "askfor %s %d (%s) peer=%d\n", inv.ToString(), nRequestTime, DateTimeStrFormat("%H:%M:%S", nRequestTime/1000000), id);

	// Make sure not to reuse time indexes to keep things in the same order
	int64_t nNow = GetTimeMicros() - 1000000;
	static int64_t nLastTime;
	++nLastTime;
	nNow = std::max(nNow, nLastTime);
	nLastTime = nNow;

	// Each retry is 2 minutes after the last
	nRequestTime = std::max(nRequestTime + 2 * 60 * 1000000, nNow);
	if (it != mapAlreadyAskedFor.end())
	mapAlreadyAskedFor.update(it, nRequestTime);
	else
	mapAlreadyAskedFor.insert(std::make_pair(inv, nRequestTime));
	mapAskFor.insert(std::make_pair(nRequestTime, inv));
	}

	void CNode::BeginMessage(const char* pszCommand) EXCLUSIVE_LOCK_FUNCTION(cs_vSend)
	{
	ENTER_CRITICAL_SECTION(cs_vSend);
	assert(ssSend.size() == 0);
	ssSend << CMessageHeader(Params().MessageStart(), pszCommand, 0);
	LogPrint("net", "sending: %s ", SanitizeString(pszCommand));
	}

	void CNode::AbortMessage() UNLOCK_FUNCTION(cs_vSend)
	{
	ssSend.clear();

	LEAVE_CRITICAL_SECTION(cs_vSend);

	LogPrint("net", "(aborted)\n");
	}

	void CNode::EndMessage() UNLOCK_FUNCTION(cs_vSend)
	{
	// The -*messagestest options are intentionally not documented in the help message,
	// since they are only used during development to debug the networking code and are
	// not intended for end-users.
	if (mapArgs.count("-dropmessagestest") && GetRand(GetArg("-dropmessagestest", 2)) == 0)
	{
	LogPrint("net", "dropmessages DROPPING SEND MESSAGE\n");
	AbortMessage();
	return;
	}
	if (mapArgs.count("-fuzzmessagestest"))
	Fuzz(GetArg("-fuzzmessagestest", 10));

	if (ssSend.size() == 0)
	{
	LEAVE_CRITICAL_SECTION(cs_vSend);
	return;
	}
	// Set the size
	unsigned int nSize = ssSend.size() - CMessageHeader::HEADER_SIZE;
	WriteLE32((uint8_t*)&ssSend[CMessageHeader::MESSAGE_SIZE_OFFSET], nSize);

	// Set the checksum
	uint256 hash = Hash(ssSend.begin() + CMessageHeader::HEADER_SIZE, ssSend.end());
	unsigned int nChecksum = 0;
	memcpy(&nChecksum, &hash, sizeof(nChecksum));
	assert(ssSend.size () >= CMessageHeader::CHECKSUM_OFFSET + sizeof(nChecksum));
	memcpy((char*)&ssSend[CMessageHeader::CHECKSUM_OFFSET], &nChecksum, sizeof(nChecksum));

	LogPrint("net", "(%d bytes) peer=%d\n", nSize, id);

	std::deque<CSerializeData>::iterator it = vSendMsg.insert(vSendMsg.end(), CSerializeData());
	ssSend.GetAndClear(*it);
	nSendSize += (*it).size();

	// If write queue empty, attempt "optimistic write"
	if (it == vSendMsg.begin())
	SocketSendData(this);

	LEAVE_CRITICAL_SECTION(cs_vSend);
	}

	//
	// CBanDB
	//

	CBanDB::CBanDB()
	{
	pathBanlist = GetDataDir() / "banlist.dat";
	}

	bool CBanDB::Write(const banmap_t& banSet)
	{
	// Generate random temporary filename
	unsigned short randv = 0;
	GetRandBytes((unsigned char*)&randv, sizeof(randv));
	std::string tmpfn = strprintf("banlist.dat.%04x", randv);

	// serialize banlist, checksum data up to that point, then append csum
	CDataStream ssBanlist(SER_DISK, CLIENT_VERSION);
	ssBanlist << FLATDATA(Params().MessageStart());
	ssBanlist << banSet;
	uint256 hash = Hash(ssBanlist.begin(), ssBanlist.end());
	ssBanlist << hash;

	// open temp output file, and associate with CAutoFile
	boost::filesystem::path pathTmp = GetDataDir() / tmpfn;
	FILE *file = fopen(pathTmp.string().c_str(), "wb");
	CAutoFile fileout(file, SER_DISK, CLIENT_VERSION);
	if (fileout.IsNull())
	return error("%s: Failed to open file %s", __func__, pathTmp.string());

	// Write and commit header, data
	try {
	fileout << ssBanlist;
	}
	catch (const std::exception& e) {
	return error("%s: Serialize or I/O error - %s", __func__, e.what());
	}
	FileCommit(fileout.Get());
	fileout.fclose();

	// replace existing banlist.dat, if any, with new banlist.dat.XXXX
	if (!RenameOver(pathTmp, pathBanlist))
	return error("%s: Rename-into-place failed", __func__);

	return true;
	}

	bool CBanDB::Read(banmap_t& banSet)
	{
	// open input file, and associate with CAutoFile
	FILE *file = fopen(pathBanlist.string().c_str(), "rb");
	CAutoFile filein(file, SER_DISK, CLIENT_VERSION);
	if (filein.IsNull())
	return error("%s: Failed to open file %s", __func__, pathBanlist.string());

	// use file size to size memory buffer
	uint64_t fileSize = boost::filesystem::file_size(pathBanlist);
	uint64_t dataSize = 0;
	// Don't try to resize to a negative number if file is small
	if (fileSize >= sizeof(uint256))
	dataSize = fileSize - sizeof(uint256);
	vector<unsigned char> vchData;
	vchData.resize(dataSize);
	uint256 hashIn;

	// read data and checksum from file
	try {
	filein.read((char *)&vchData[0], dataSize);
	filein >> hashIn;
	}
	catch (const std::exception& e) {
	return error("%s: Deserialize or I/O error - %s", __func__, e.what());
	}
	filein.fclose();

	CDataStream ssBanlist(vchData, SER_DISK, CLIENT_VERSION);

	// verify stored checksum matches input data
	uint256 hashTmp = Hash(ssBanlist.begin(), ssBanlist.end());
	if (hashIn != hashTmp)
	return error("%s: Checksum mismatch, data corrupted", __func__);

	unsigned char pchMsgTmp[4];
	try {
	// de-serialize file header (network specific magic number) and ..
	ssBanlist >> FLATDATA(pchMsgTmp);

	// ... verify the network matches ours
	if (memcmp(pchMsgTmp, Params().MessageStart(), sizeof(pchMsgTmp)))
	return error("%s: Invalid network magic number", __func__);

	// de-serialize address data into one CAddrMan object
	ssBanlist >> banSet;
	}
	catch (const std::exception& e) {
	return error("%s: Deserialize or I/O error - %s", __func__, e.what());
	}

	return true;
	}

	void DumpBanlist()
	{
	int64_t nStart = GetTimeMillis();

	CNode::SweepBanned(); //clean unused entries (if bantime has expired)

	CBanDB bandb;
	banmap_t banmap;
	CNode::GetBanned(banmap);
	bandb.Write(banmap);

	LogPrint("net", "Flushed %d banned node ips/subnets to banlist.dat %dms\n",
	banmap.size(), GetTimeMillis() - nStart);
	}

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