//this file is part of eMule
//Copyright (C)2002-2008 Merkur ( strEmail.Format("%s@%s", "devteam", "emule-project.net") / http://www.emule-project.net )
//
//This program is free software; you can redistribute it and/or
//modify it under the terms of the GNU General Public License
//as published by the Free Software Foundation; either
//version 2 of the License, or (at your option) any later version.
//
//This program is distributed in the hope that it will be useful,
//but WITHOUT ANY WARRANTY; without even the implied warranty of
//MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//GNU General Public License for more details.
//
//You should have received a copy of the GNU General Public License
//along with this program; if not, write to the Free Software
//Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#include "stdafx.h"
#include "emule.h"
#include "UDPSocket.h"
#include "SearchList.h"
#include "DownloadQueue.h"
#include "Statistics.h"
#include "Server.h"
#include "Preferences.h"
#include "OtherFunctions.h"
#include "ServerList.h"
#include "Opcodes.h"
#include "SafeFile.h"
#include "PartFile.h"
#include "Packets.h"
#include "IPFilter.h"
#include "emuledlg.h"
#include "ServerWnd.h"
#include "SearchDlg.h"
#include "Log.h"
#include "Sockets.h"
#include "FirewallOpener.h" // Improved ICS-Firewall support [MoNKi] - Max

//Xman
#include "BandWidthControl.h" // Maella -Accurate measure of bandwidth: eDonkey data + control, network adapter-

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif


#pragma pack(1)
struct SServerUDPPacket
{
	BYTE* packet;
	int size;
	uint32 dwIP;
	uint16 nPort;
};
#pragma pack()

struct SRawServerPacket
{
	SRawServerPacket(BYTE* pPacket, UINT uSize, uint16 nPort) {
		m_pPacket = pPacket;
		m_uSize = uSize;
		m_nPort = nPort;
	}
	~SRawServerPacket() {
		delete[] m_pPacket;
	}
	BYTE* m_pPacket;
	UINT m_uSize;
	uint16 m_nPort;
};

struct SServerDNSRequest
{
	SServerDNSRequest(HANDLE hDNSTask, CServer* pServer) {
		m_dwCreated = GetTickCount();
		m_hDNSTask = hDNSTask;
		memset(m_DnsHostBuffer, 0, sizeof m_DnsHostBuffer);
		m_pServer = pServer;
	}
	~SServerDNSRequest() {
		if (m_hDNSTask)
			WSACancelAsyncRequest(m_hDNSTask);
		delete m_pServer;
		POSITION pos = m_aPackets.GetHeadPosition();
		while (pos)
			delete m_aPackets.GetNext(pos);
	}
	DWORD m_dwCreated;
	HANDLE m_hDNSTask;
	char m_DnsHostBuffer[MAXGETHOSTSTRUCT];
	CServer* m_pServer;
	CTypedPtrList<CPtrList, SRawServerPacket*> m_aPackets;
};

#define WM_DNSLOOKUPDONE	(WM_USER+0x101)		// does not need to be placed in "UserMsgs.h"

BEGIN_MESSAGE_MAP(CUDPSocketWnd, CWnd)
	ON_MESSAGE(WM_DNSLOOKUPDONE, OnDNSLookupDone)
END_MESSAGE_MAP()

LRESULT CUDPSocketWnd::OnDNSLookupDone(WPARAM wParam, LPARAM lParam)
{
	m_pOwner->DnsLookupDone(wParam, lParam);
	return true;
}

CUDPSocket::CUDPSocket()
{
	m_hWndResolveMessage = NULL;
	m_bWouldBlock = false;
}

CUDPSocket::~CUDPSocket()
{
    theApp.uploadBandwidthThrottler->RemoveFromAllQueues(this); // ZZ:UploadBandWithThrottler (UDP)

	//Xman Code Improvement
	/*
	POSITION pos = controlpacket_queue.GetHeadPosition();
	while (pos) {
		SServerUDPPacket* p = controlpacket_queue.GetNext(pos);
		delete[] p->packet;
		delete p;
	}
	m_udpwnd.DestroyWindow();

	pos = m_aDNSReqs.GetHeadPosition();
	*/
	while (!controlpacket_queue.IsEmpty())
	{
		SServerUDPPacket* p = controlpacket_queue.RemoveHead();
		delete[] p->packet;
		delete p;
	}
	m_udpwnd.DestroyWindow();

	POSITION pos = m_aDNSReqs.GetHeadPosition();
	//Xman end
	while (pos)
		delete m_aDNSReqs.GetNext(pos);
}

bool CUDPSocket::Create()
{
	if (thePrefs.GetServerUDPPort())
	{
		VERIFY( m_udpwnd.CreateEx(0, AfxRegisterWndClass(0), _T("eMule Async DNS Resolve Socket Wnd #1"), WS_OVERLAPPED, 0, 0, 0, 0, NULL, NULL));
	    m_hWndResolveMessage = m_udpwnd.m_hWnd;
	    m_udpwnd.m_pOwner = this;
		if (!CAsyncSocket::Create(thePrefs.GetServerUDPPort()==0xFFFF ? 0 : thePrefs.GetServerUDPPort(), SOCK_DGRAM, FD_READ | FD_WRITE, thePrefs.GetBindAddrW())){
			LogError(LOG_STATUSBAR, _T("Error: Server UDP socket: Failed to create server UDP socket - %s"), GetErrorMessage(GetLastError()));
			return false;
		}
		// ==> UPnP support [MoNKi] - leuk_he
		/*
#ifdef DUAL_UPNP //zz_fly :: dual upnp
		//ACAT UPnP
		if(thePrefs.m_bUseACATUPnPCurrent && thePrefs.GetUPnPNat()){
			CString client;
			UINT port;
			MyUPnP::UPNPNAT_MAPPING mapping;

			GetSockName(client, port);
			mapping.internalPort = mapping.externalPort = (WORD)port;
			mapping.protocol = MyUPnP::UNAT_UDP;
			mapping.description = "Server UDP Port";
			theApp.AddUPnPNatPort(&mapping, thePrefs.GetUPnPNatTryRandom());
		}
#endif //zz_fly :: dual upnp
		*/
		// Don't add UPnP port mapping if is a random port and we don't want
		// to clear mappings on close
		if(theApp.m_UPnP_IGDControlPoint->IsUpnpAcceptsPorts() &&
			(!(thePrefs.GetServerUDPPort()==0xFFFF && !thePrefs.GetUPnPClearOnClose())))
		{
			CString client;
			UINT port;
			GetSockName(client, port);

			// ==> Improved ICS-Firewall support [MoNKi] - Max
			if(thePrefs.GetICFSupport() && thePrefs.GetICFSupportServerUDP()){
				if (theApp.m_pFirewallOpener->OpenPort((uint16)port, NAT_PROTOCOL_UDP, EMULE_DEFAULTRULENAME_SERVERUDP, thePrefs.IsOpenPortsOnStartupEnabled() || thePrefs.GetServerUDPPort()==0xFFFF))
					Log(GetResString(IDS_FO_TEMPUDP_S), port);
				else
					Log(GetResString(IDS_FO_TEMPUDP_F), port);
			}
			// <== Improved ICS-Firewall support [MoNKi] - Max

			theApp.m_UPnP_IGDControlPoint->AddPortMapping((uint16)port,
				CUPnP_IGDControlPoint::UNAT_UDP,
				_T("Server UDP Port"));
		}
		// <== UPnP support [MoNKi] - leuk_he

		return true;
	}
	return false;
}

void CUDPSocket::OnReceive(int nErrorCode)
{
	if (nErrorCode)
	{
		if (thePrefs.GetDebugServerUDPLevel() > 0)
			Debug(_T("Error: Server UDP socket: Receive failed - %s\n"), GetErrorMessage(nErrorCode, 1));
		if (thePrefs.GetVerbose())
			DebugLogError(_T("Error: Server UDP socket: Receive failed - %s"), GetErrorMessage(nErrorCode, 1));
	}

	BYTE buffer[5000];
	BYTE* pBuffer = buffer;
	SOCKADDR_IN sockAddr = {0};
	int iSockAddrLen = sizeof sockAddr;
	int length = ReceiveFrom(buffer, sizeof buffer, (SOCKADDR*)&sockAddr, &iSockAddrLen);
	if (length != SOCKET_ERROR)
	{
		//Xman
		// Maella -Accurate measure of bandwidth: eDonkey data + control, network adapter-
		if(length > 0){ 		
			theApp.pBandWidthControl->AddeMuleInUDPOverall(length);
		}
		// Maella end

		int nPayLoadLen = length;
		CServer* pServer = theApp.serverlist->GetServerByIPUDP(sockAddr.sin_addr.S_un.S_addr, ntohs(sockAddr.sin_port), true);
		if (pServer != NULL && thePrefs.IsServerCryptLayerUDPEnabled() &&
			((pServer->GetServerKeyUDP() != 0 && pServer->SupportsObfuscationUDP()) || (pServer->GetCryptPingReplyPending() && pServer->GetChallenge() != 0)))
		{
			// TODO
			uint32 dwKey = 0;
			if (pServer->GetCryptPingReplyPending() && pServer->GetChallenge() != 0 /* && pServer->GetPort() == ntohs(sockAddr.sin_port) - 12 */)
				dwKey = pServer->GetChallenge();
			else
				dwKey = pServer->GetServerKeyUDP();

			ASSERT( dwKey != 0 );
			nPayLoadLen = DecryptReceivedServer(buffer, length, &pBuffer, dwKey,sockAddr.sin_addr.S_un.S_addr);
			if (nPayLoadLen == length)
				DebugLogWarning(_T("Expected encrypted packet, but received unencrytped from server %s, UDPKey %u, Challenge: %u"), pServer->GetListName(), pServer->GetServerKeyUDP(), pServer->GetChallenge());
			else if (thePrefs.GetDebugServerUDPLevel() > 0)
				DEBUG_ONLY(DebugLog(_T("Received encrypted packet from server %s, UDPKey %u, Challenge: %u"), pServer->GetListName(), pServer->GetServerKeyUDP(), pServer->GetChallenge()));
		}

		if (pBuffer[0] == OP_EDONKEYPROT)
			ProcessPacket(pBuffer+2, nPayLoadLen-2, pBuffer[1], sockAddr.sin_addr.S_un.S_addr, ntohs(sockAddr.sin_port));
		else if (thePrefs.GetDebugServerUDPLevel() > 0)
			Debug(_T("***NOTE: ServerUDPMessage from %s:%u - Unknown protocol 0x%02x\n, Encrypted: %s"), ipstr(sockAddr.sin_addr), ntohs(sockAddr.sin_port)-4, pBuffer[0], (nPayLoadLen == length) ? _T("Yes") : _T("No"));
	}
	else
	{
		DWORD dwError = WSAGetLastError();
		if (thePrefs.GetDebugServerUDPLevel() > 0) {
			CString strServerInfo;
			if (iSockAddrLen > 0 && sockAddr.sin_addr.S_un.S_addr != 0 && sockAddr.sin_addr.S_un.S_addr != INADDR_NONE)
				strServerInfo.Format(_T(" from %s:%u"), ipstr(sockAddr.sin_addr), ntohs(sockAddr.sin_port)-4);
			Debug(_T("Error: Server UDP socket: Failed to receive data%s: %s\n"), strServerInfo, GetErrorMessage(dwError, 1));
		}
		if (dwError == WSAECONNRESET)
		{
			// Depending on local and remote OS and depending on used local (remote?) router we may receive
			// WSAECONNRESET errors. According some KB articels, this is a special way of winsock to report 
			// that a sent UDP packet was not received by the remote host because it was not listening on 
			// the specified port -> no server running there.
			//

			// If we are not currently pinging this server, increase the failure counter
			CServer* pServer = theApp.serverlist->GetServerByIPUDP(sockAddr.sin_addr.S_un.S_addr, ntohs(sockAddr.sin_port), true);
			if (pServer && !pServer->GetCryptPingReplyPending() && GetTickCount() - pServer->GetLastPinged() >= SEC2MS(30))
			{
				pServer->AddFailedCount();
				theApp.emuledlg->serverwnd->serverlistctrl.RefreshServer(pServer);
			}
			else if (pServer && pServer->GetCryptPingReplyPending())
				DEBUG_ONLY(DebugLog(_T("CryptPing failed (WSACONNRESET) for server %s"), pServer->GetListName()));

		}
		else if (thePrefs.GetVerbose())
		{
			CString strServerInfo;
			if (iSockAddrLen > 0 && sockAddr.sin_addr.S_un.S_addr != 0 && sockAddr.sin_addr.S_un.S_addr != INADDR_NONE)
				strServerInfo.Format(_T(" from %s:%u"), ipstr(sockAddr.sin_addr), ntohs(sockAddr.sin_port)-4);
			DebugLogError(_T("Error: Server UDP socket: Failed to receive data%s: %s"), strServerInfo, GetErrorMessage(dwError, 1));
		}
	}
}

bool CUDPSocket::ProcessPacket(const BYTE* packet, UINT size, UINT opcode, uint32 nIP, uint16 nUDPPort)
{
	try
	{
		theStats.AddDownDataOverheadServer(size);
		CServer* pServer = theApp.serverlist->GetServerByIPUDP(nIP, nUDPPort, true);
		if (pServer) {
			pServer->ResetFailedCount();
			theApp.emuledlg->serverwnd->serverlistctrl.RefreshServer(pServer);
		}

		switch (opcode)
		{
			case OP_GLOBSEARCHRES:{
				CSafeMemFile data(packet, size);
				// process all search result packets
				int iLeft;
				int iDbgPacket = 1;
				do{
					if (thePrefs.GetDebugServerUDPLevel() > 0){
						if (data.GetLength() - data.GetPosition() >= 16+4+2){
							const BYTE* pDbgPacket = data.GetBuffer() + data.GetPosition();
							Debug(_T("ServerUDPMessage from %-21s - OP_GlobSearchResult(%u); %s\n"), ipstr(nIP, nUDPPort-4), iDbgPacket++, DbgGetFileInfo(pDbgPacket), DbgGetClientID(PeekUInt32(pDbgPacket+16)), PeekUInt16(pDbgPacket+20));
						}
					}
					UINT uResultCount = theApp.searchlist->ProcessUDPSearchAnswer(data, true/*pServer->GetUnicodeSupport()*/, nIP, nUDPPort-4);
					theApp.emuledlg->searchwnd->AddGlobalEd2kSearchResults(uResultCount);

					// check if there is another source packet
					iLeft = (int)(data.GetLength() - data.GetPosition());
					if (iLeft >= 2){
						uint8 protocol = data.ReadUInt8();
						iLeft--;
						if (protocol != OP_EDONKEYPROT){
							data.Seek(-1, SEEK_CUR);
							iLeft += 1;
							break;
						}

						uint8 opcode = data.ReadUInt8();
						iLeft--;
						if (opcode != OP_GLOBSEARCHRES){
							data.Seek(-2, SEEK_CUR);
							iLeft += 2;
							break;
						}
					}
				}
				while (iLeft > 0);

				if (iLeft > 0 && thePrefs.GetDebugServerUDPLevel() > 0){
					Debug(_T("***NOTE: OP_GlobSearchResult contains %d additional bytes\n"), iLeft);
					if (thePrefs.GetDebugServerUDPLevel() > 1)
						DebugHexDump(data);
				}
				break;
			}
			case OP_GLOBFOUNDSOURCES:{
				CSafeMemFile data(packet, size);
				// process all source packets
				int iLeft;
				int iDbgPacket = 1;
				do{
					uchar fileid[16];
					data.ReadHash16(fileid);
					if (thePrefs.GetDebugServerUDPLevel() > 0)
						Debug(_T("ServerUDPMessage from %-21s - OP_GlobFoundSources(%u); %s\n"), ipstr(nIP, nUDPPort-4), iDbgPacket++, DbgGetFileInfo(fileid));
					if (CPartFile* file = theApp.downloadqueue->GetFileByID(fileid))
						file->AddSources(&data, nIP, nUDPPort-4, false);
					else{
						// skip sources for that file
						UINT count = data.ReadUInt8();
						data.Seek(count*(4+2), SEEK_CUR);
					}

					// check if there is another source packet
					iLeft = (int)(data.GetLength() - data.GetPosition());
					if (iLeft >= 2){
						uint8 protocol = data.ReadUInt8();
						iLeft--;
						if (protocol != OP_EDONKEYPROT){
							data.Seek(-1, SEEK_CUR);
							iLeft += 1;
							break;
						}

						uint8 opcode = data.ReadUInt8();
						iLeft--;
						if (opcode != OP_GLOBFOUNDSOURCES){
							data.Seek(-2, SEEK_CUR);
							iLeft += 2;
							break;
						}
					}
				}
				while (iLeft > 0);

				if (iLeft > 0 && thePrefs.GetDebugServerUDPLevel() > 0){
					Debug(_T("***NOTE: OP_GlobFoundSources contains %d additional bytes\n"), iLeft);
					if (thePrefs.GetDebugServerUDPLevel() > 1)
						DebugHexDump(data);
				}
				break;
			}
 			case OP_GLOBSERVSTATRES:{
				if (thePrefs.GetDebugServerUDPLevel() > 0)
					Debug(_T("ServerUDPMessage from %-21s - OP_GlobServStatRes\n"), ipstr(nIP, nUDPPort-4));
				if (size < 12 || pServer == NULL)
					return true;
				uint32 challenge = PeekUInt32(packet);
				if (challenge != pServer->GetChallenge()){
					if (thePrefs.GetDebugServerUDPLevel() > 0)
						Debug(_T("***NOTE: Received unexpected challenge %08x (waiting on packet with challenge %08x)\n"), challenge, pServer->GetChallenge());
					return true;
				}
				if (pServer != NULL){
					pServer->SetChallenge(0);
					pServer->SetCryptPingReplyPending(false);
					uint32 tNow = (uint32)time(NULL);
					pServer->SetLastPingedTime(tNow - (rand() % HR2S(1))); // if we used Obfuscated ping, we still need to reset the time properly
				}
				uint32 cur_user = PeekUInt32(packet+4);
				uint32 cur_files = PeekUInt32(packet+8);
				uint32 cur_maxusers = 0;
				uint32 cur_softfiles = 0;
				uint32 cur_hardfiles = 0;
				uint32 uUDPFlags = 0;
				uint32 uLowIDUsers = 0;
				uint32 dwServerUDPKey = 0;
				uint16 nTCPObfuscationPort = 0;
				uint16 nUDPObfuscationPort = 0;

				if (size >= 16){
					cur_maxusers = PeekUInt32(packet+12);
				}
				if (size >= 24){
					cur_softfiles = PeekUInt32(packet+16);
					cur_hardfiles = PeekUInt32(packet+20);
				}
				if (size >= 28){
					uUDPFlags = PeekUInt32(packet+24);
					if (thePrefs.GetDebugServerUDPLevel() > 0){
						CString strInfo;
						const DWORD dwKnownBits = SRV_UDPFLG_EXT_GETSOURCES | SRV_UDPFLG_EXT_GETFILES | SRV_UDPFLG_NEWTAGS | SRV_UDPFLG_UNICODE | SRV_UDPFLG_EXT_GETSOURCES2 | SRV_UDPFLG_LARGEFILES | SRV_UDPFLG_UDPOBFUSCATION | SRV_UDPFLG_TCPOBFUSCATION;
						if (uUDPFlags & ~dwKnownBits)
							strInfo.AppendFormat(_T("  ***UnkUDPFlags=0x%08x"), uUDPFlags & ~dwKnownBits);
						if (uUDPFlags & SRV_UDPFLG_EXT_GETSOURCES)
							strInfo.AppendFormat(_T("  ExtGetSources=1"));
						if (uUDPFlags & SRV_UDPFLG_EXT_GETSOURCES2)
							strInfo.AppendFormat(_T("  ExtGetSources2=1"));
						if (uUDPFlags & SRV_UDPFLG_EXT_GETFILES)
							strInfo.AppendFormat(_T("  ExtGetFiles=1"));
						if (uUDPFlags & SRV_UDPFLG_NEWTAGS)
							strInfo.AppendFormat(_T("  NewTags=1"));
						if (uUDPFlags & SRV_UDPFLG_UNICODE)
							strInfo.AppendFormat(_T("  Unicode=1"));
						if (uUDPFlags & SRV_UDPFLG_LARGEFILES)
							strInfo.AppendFormat(_T("  LargeFiles=1"));
						if (uUDPFlags & SRV_UDPFLG_UDPOBFUSCATION)
							strInfo.AppendFormat(_T("  UDP_Obfuscation=1"));
						if (uUDPFlags & SRV_UDPFLG_TCPOBFUSCATION)
							strInfo.AppendFormat(_T("  TCP_Obfuscation=1"));
						Debug(_T("%s\n"), strInfo);
					}
				}
				if (size >= 32){
					uLowIDUsers = PeekUInt32(packet+28);
				}
				if (size >= 40){
					// TODO debug check if this packet was encrypted if it has a key
					nUDPObfuscationPort = PeekUInt16(packet+32);	
					nTCPObfuscationPort = PeekUInt16(packet+34);;
					dwServerUDPKey = PeekUInt32(packet+36);
					if (pServer != NULL)
						DEBUG_ONLY(DebugLog(_T("New UDP key for server %s: UDPKey %u - Old Key %u"), pServer->GetListName(), dwServerUDPKey, pServer->GetServerKeyUDP()));
				}
				if (thePrefs.GetDebugServerUDPLevel() > 0){
					if (size > 40){
						Debug(_T("***NOTE: OP_GlobServStatRes contains %d additional bytes\n"), size-40);
						if (thePrefs.GetDebugServerUDPLevel() > 1)
							DbgGetHexDump(packet+32, size-32);
					}
				}
				if (pServer){
					pServer->SetPing(::GetTickCount() - pServer->GetLastPinged());
					pServer->SetUserCount(cur_user);
					pServer->SetFileCount(cur_files);
					pServer->SetMaxUsers(cur_maxusers);
					pServer->SetSoftFiles(cur_softfiles);
					pServer->SetHardFiles(cur_hardfiles);
					pServer->SetServerKeyUDP(dwServerUDPKey);
					pServer->SetObfuscationPortTCP(nTCPObfuscationPort);
					pServer->SetObfuscationPortUDP(nUDPObfuscationPort);
					// if the received UDP flags do not match any already stored UDP flags, 
					// reset the server version string because the version (which was determined by last connecting to
					// that server) is most likely not accurat any longer.
					// this may also give 'false' results because we don't know the UDP flags when connecting to a server
					// with TCP.
					//if (pServer->GetUDPFlags() != uUDPFlags)
					//	pServer->SetVersion(_T(""));
					pServer->SetUDPFlags(uUDPFlags);
					pServer->SetLowIDUsers(uLowIDUsers);
					theApp.emuledlg->serverwnd->serverlistctrl.RefreshServer(pServer);
				
					pServer->SetLastDescPingedCount(false);
					if (pServer->GetLastDescPingedCount() < 2)
					{
						// eserver 16.45+ supports a new OP_SERVER_DESC_RES answer, if the OP_SERVER_DESC_REQ contains a uint32
						// challenge, the server returns additional info with OP_SERVER_DESC_RES. To properly distinguish the
						// old and new OP_SERVER_DESC_RES answer, the challenge has to be selected carefully. The first 2 bytes 
						// of the challenge (in network byte order) MUST NOT be a valid string-len-int16!
						Packet* packet = new Packet(OP_SERVER_DESC_REQ, 4);
						uint32 uDescReqChallenge = ((uint32)GetRandomUInt16() << 16) + INV_SERV_DESC_LEN; // 0xF0FF = an 'invalid' string length.
						pServer->SetDescReqChallenge(uDescReqChallenge);
						PokeUInt32(packet->pBuffer, uDescReqChallenge);
						theStats.AddUpDataOverheadServer(packet->size);
						if (thePrefs.GetDebugServerUDPLevel() > 0)
							Debug(_T(">>> Sending OP__ServDescReq     to server %s:%u, challenge %08x\n"), pServer->GetAddress(), pServer->GetPort(), uDescReqChallenge);
						theApp.serverconnect->SendUDPPacket(packet, pServer, true);
					}
					else
					{
						pServer->SetLastDescPingedCount(true);
					}
				}
				break;
			}

 			case OP_SERVER_DESC_RES:{
				if (thePrefs.GetDebugServerUDPLevel() > 0)
					Debug(_T("ServerUDPMessage from %-21s - OP_ServerDescRes\n"), ipstr(nIP, nUDPPort-4));
				if (!pServer)
					return true;

				// old packet: <name_len 2><name name_len><desc_len 2 desc_en>
				// new packet: <challenge 4><taglist>
				//
				// NOTE: To properly distinguish between the two packets which are both useing the same opcode...
				// the first two bytes of <challenge> (in network byte order) have to be an invalid <name_len> at least.

				CSafeMemFile srvinfo(packet, size);
				if (size >= 8 && PeekUInt16(packet) == INV_SERV_DESC_LEN)
				{
					if (pServer->GetDescReqChallenge() != 0 && PeekUInt32(packet) == pServer->GetDescReqChallenge())
					{
						pServer->SetDescReqChallenge(0);
						(void)srvinfo.ReadUInt32(); // skip challenge
						UINT uTags = srvinfo.ReadUInt32();
						for (UINT i = 0; i < uTags; i++)
						{
							CTag tag(&srvinfo, true/*pServer->GetUnicodeSupport()*/);
							if (tag.GetNameID() == ST_SERVERNAME && tag.IsStr())
								pServer->SetListName(tag.GetStr());
							else if (tag.GetNameID() == ST_DESCRIPTION && tag.IsStr())
								pServer->SetDescription(tag.GetStr());
							else if (tag.GetNameID() == ST_DYNIP && tag.IsStr())
							{
								// Verify that we really received a DN.
								if (inet_addr(CStringA(tag.GetStr())) == INADDR_NONE)
								{
									CString strOldDynIP = pServer->GetDynIP();
									pServer->SetDynIP(tag.GetStr());
									// If a dynIP-server changed its address or, if this is the
									// first time we get the dynIP-address for a server which we
									// already have as non-dynIP in our list, we need to remove
									// an already available server with the same 'dynIP:port'.
									if (strOldDynIP.CompareNoCase(pServer->GetDynIP()) != 0)
										theApp.serverlist->RemoveDuplicatesByAddress(pServer);
								}
							}
							else if (tag.GetNameID() == ST_VERSION && tag.IsStr())
								pServer->SetVersion(tag.GetStr());
							else if (tag.GetNameID() == ST_VERSION && tag.IsInt()){
								CString strVersion;
								strVersion.Format(_T("%u.%02u"), tag.GetInt() >> 16, tag.GetInt() & 0xFFFF);
								pServer->SetVersion(strVersion);
							}
							else if (tag.GetNameID() == ST_AUXPORTSLIST && tag.IsStr())
								// currently not implemented.
								; // <string> = <port> [, <port>...]
							else{
								if (thePrefs.GetDebugServerUDPLevel() > 0)
									Debug(_T("***NOTE: Unknown tag in OP_ServerDescRes: %s\n"), tag.GetFullInfo());
							}
						}
					}
					else
					{
						// A server sent us a new server description packet (including a challenge) although we did not
						// ask for it. This may happen, if there are multiple servers running on the same machine with
						// multiple IPs. If such a server is asked for a description, the server will answer 2 times,
						// but with the same IP.

						if (thePrefs.GetDebugServerUDPLevel() > 0)
							Debug(_T("***NOTE: Received unexpected new format OP_ServerDescRes from %s with challenge %08x (waiting on packet with challenge %08x)\n"), ipstr(nIP, nUDPPort-4), PeekUInt32(packet), pServer->GetDescReqChallenge());
						; // ignore this packet
					}
				}
				else
				{
					CString strName = srvinfo.ReadString(true/*pServer->GetUnicodeSupport()*/);
					CString strDesc = srvinfo.ReadString(true/*pServer->GetUnicodeSupport()*/);
					pServer->SetDescription(strDesc);
					pServer->SetListName(strName);
				}

				if (thePrefs.GetDebugServerUDPLevel() > 0){
					int iAddData = (int)(srvinfo.GetLength() - srvinfo.GetPosition());
					if (iAddData > 0){
						Debug(_T("***NOTE: OP_ServerDescRes contains %d additional bytes\n"), iAddData);
						if (thePrefs.GetDebugServerUDPLevel() > 1)
							DebugHexDump(srvinfo);
					}
				}
				theApp.emuledlg->serverwnd->serverlistctrl.RefreshServer(pServer);
				break;
			}
			default:
				if (thePrefs.GetDebugServerUDPLevel() > 0)
					Debug(_T("***NOTE: ServerUDPMessage from %s - Unknown packet: opcode=0x%02X  %s\n"), ipstr(nIP, nUDPPort-4), opcode, DbgGetHexDump(packet, size));
				return false;
		}

		return true;
	}
	catch(CFileException* error){
		TCHAR szError[MAX_CFEXP_ERRORMSG];
		error->m_strFileName = _T("server UDP packet");
		if (!error->GetErrorMessage(szError, ARRSIZE(szError)))
			szError[0] = _T('\0');
		ProcessPacketError(size, opcode, nIP, nUDPPort, szError);
		error->Delete();
		//ASSERT(0);
		if (opcode==OP_GLOBSEARCHRES || opcode==OP_GLOBFOUNDSOURCES)
			return true;
	}
	catch(CMemoryException* error){
		TCHAR szError[MAX_CFEXP_ERRORMSG];
		if (!error->GetErrorMessage(szError, ARRSIZE(szError)))
			szError[0] = _T('\0');
		ProcessPacketError(size, opcode, nIP, nUDPPort, szError);
		error->Delete();
		//ASSERT(0);
		if (opcode==OP_GLOBSEARCHRES || opcode==OP_GLOBFOUNDSOURCES)
			return true;
	}
	catch(CString error){
		ProcessPacketError(size, opcode, nIP, nUDPPort, error);
		//ASSERT(0);
	}
#ifndef _DEBUG
	catch(...){
		ProcessPacketError(size, opcode, nIP, nUDPPort, _T("Unknown exception"));
		ASSERT(0);
	}
#endif
	return false;
}

void CUDPSocket::ProcessPacketError(UINT size, UINT opcode, uint32 nIP, uint16 nUDPPort, LPCTSTR pszError)
{
	if (thePrefs.GetVerbose())
	{
		CString strName;
		CServer* pServer = theApp.serverlist->GetServerByIPUDP(nIP, nUDPPort);
		if (pServer)
			strName = _T(" (") + pServer->GetListName() + _T(")");
		DebugLogWarning(false, _T("Error: Failed to process server UDP packet from %s:%u%s opcode=0x%02x size=%u - %s"), ipstr(nIP), nUDPPort, strName, opcode, size, pszError);
	}
}

void CUDPSocket::DnsLookupDone(WPARAM wp, LPARAM lp)
{
	// A Winsock DNS task has completed. Search the according application data for that
	// task handle.
	SServerDNSRequest* pDNSReq = NULL;
	HANDLE hDNSTask = (HANDLE)wp;
	POSITION pos = m_aDNSReqs.GetHeadPosition();
	while (pos) {
		POSITION posPrev = pos;
		SServerDNSRequest* pCurDNSReq = m_aDNSReqs.GetNext(pos);
		if (pCurDNSReq->m_hDNSTask == hDNSTask) {
			// Remove this DNS task from our list
			m_aDNSReqs.RemoveAt(posPrev);
			pDNSReq = pCurDNSReq;
			break;
		}
	}
	if (pDNSReq == NULL) {
		if (thePrefs.GetVerbose())
			DebugLogError(_T("Error: Server UDP socket: Unknown DNS task completed"));
		return;
	}

	// DNS task did complete successfully?
	if (WSAGETASYNCERROR(lp) != 0) {
		if (thePrefs.GetVerbose())
			DebugLogWarning(_T("Error: Server UDP socket: Failed to resolve address for server '%s' (%s) - %s"), pDNSReq->m_pServer->GetListName(), pDNSReq->m_pServer->GetAddress(), GetErrorMessage(WSAGETASYNCERROR(lp), 1));
		delete pDNSReq;
		return;
	}

	// Get the IP value
	uint32 nIP = INADDR_NONE;
	int iBufLen = WSAGETASYNCBUFLEN(lp);
	if (iBufLen >= sizeof(HOSTENT)) {
		LPHOSTENT pHost = (LPHOSTENT)pDNSReq->m_DnsHostBuffer;
		if (pHost->h_length == 4 && pHost->h_addr_list && pHost->h_addr_list[0])
			nIP = ((LPIN_ADDR)(pHost->h_addr_list[0]))->s_addr;
	}

	if (nIP != INADDR_NONE)
	{
		DEBUG_ONLY( DebugLog(_T("Resolved DN for server '%s': IP=%s"), pDNSReq->m_pServer->GetAddress(), ipstr(nIP)) );

		bool bRemoveServer = false;
		if (!IsGoodIP(nIP)) {
			// However, if we are currently connected to a "not-good-ip", that IP can't
			// be that bad -- may only happen when debugging in a LAN.
			CServer* pConnectedServer = theApp.serverconnect->GetCurrentServer();
			if (!pConnectedServer || pConnectedServer->GetIP() != nIP) {
				if (thePrefs.GetLogFilteredIPs())
					AddDebugLogLine(false, _T("IPFilter(UDP/DNSResolve): Filtered server \"%s\" (IP=%s) - Invalid IP or LAN address."), pDNSReq->m_pServer->GetAddress(), ipstr(nIP));
				bRemoveServer = true;
			}
		}
		if (!bRemoveServer && thePrefs.GetFilterServerByIP() && theApp.ipfilter->IsFiltered(nIP)) {
			if (thePrefs.GetLogFilteredIPs())
				AddDebugLogLine(false, _T("IPFilter(UDP/DNSResolve): Filtered server \"%s\" (IP=%s) - IP filter (%s)"), pDNSReq->m_pServer->GetAddress(), ipstr(nIP), theApp.ipfilter->GetLastHit());
			bRemoveServer = true;
		}

		CServer* pServer = theApp.serverlist->GetServerByAddress(pDNSReq->m_pServer->GetAddress(), pDNSReq->m_pServer->GetPort());
		if (pServer) {
			pServer->SetIP(nIP);
			// If we already have entries in the server list (dynIP-servers without a DN)
			// with the same IP as this dynIP-server, remove the duplicates.
			theApp.serverlist->RemoveDuplicatesByIP(pServer);
		}

		if (bRemoveServer) {
			if (pServer)
				theApp.emuledlg->serverwnd->serverlistctrl.RemoveServer(pServer);
			delete pDNSReq;
			return;
		}
		//zz_fly :: support dynamic ip servers :: DolphinX :: Start
		if (pServer)
			pServer->ResetIP2Country(); //EastShare - added by AndCycle, IP to Country
		//zz_fly :: End

		// Send all of the queued packets for this server.
		POSITION posPacket = pDNSReq->m_aPackets.GetHeadPosition();
		while (posPacket) {
			SRawServerPacket* pServerPacket = pDNSReq->m_aPackets.GetNext(posPacket);
			SendBuffer(nIP, pServerPacket->m_nPort, pServerPacket->m_pPacket, pServerPacket->m_uSize);
			// Detach packet data
			pServerPacket->m_pPacket = NULL;
			pServerPacket->m_uSize = 0;
		}
	}
	else
	{
		// still no valid IP for this server
		if (thePrefs.GetVerbose())
			DebugLogWarning(_T("Error: Server UDP socket: Failed to resolve address for server '%s' (%s)"), pDNSReq->m_pServer->GetListName(), pDNSReq->m_pServer->GetAddress());
	}
	delete pDNSReq;
}

void CUDPSocket::OnSend(int nErrorCode)
{
	if (nErrorCode) {
		if (thePrefs.GetVerbose())
			DebugLogError(_T("Error: Server UDP socket: Failed to send packet - %s"), GetErrorMessage(nErrorCode, 1));
		return;
	}
	m_bWouldBlock = false;

// ZZ:UploadBandWithThrottler (UDP) -->
    sendLocker.Lock();
    if (!controlpacket_queue.IsEmpty()) {
        theApp.uploadBandwidthThrottler->QueueForSendingControlPacket(this);
    }
    sendLocker.Unlock();
// <-- ZZ:UploadBandWithThrottler (UDP)
}

SocketSentBytes CUDPSocket::SendControlData(uint32 maxNumberOfBytesToSend, uint32 /*minFragSize*/) // ZZ:UploadBandWithThrottler (UDP)
{
// ZZ:UploadBandWithThrottler (UDP) -->
	// NOTE: *** This function is invoked from a *different* thread!
    sendLocker.Lock();

    uint32 sentBytes = 0;
// <-- ZZ:UploadBandWithThrottler (UDP)
    while (controlpacket_queue.GetHeadPosition() != 0 && !IsBusy() && sentBytes < maxNumberOfBytesToSend) // ZZ:UploadBandWithThrottler (UDP)
	{
		SServerUDPPacket* packet = controlpacket_queue.GetHead();
        int sendSuccess = SendTo(packet->packet, packet->size, packet->dwIP, packet->nPort);
		if (sendSuccess >= 0)
		{
            if (sendSuccess > 0) {
                sentBytes += packet->size; // ZZ:UploadBandWithThrottler (UDP)
            }
			//Xman
			// Maella -Accurate measure of bandwidth: eDonkey data + control, network adapter-
			sentBytes += (20+8); //Header
			//Xman end

			controlpacket_queue.RemoveHead();
			delete[] packet->packet;
			delete packet;
		}
	}

// ZZ:UploadBandWithThrottler (UDP) -->
    if (!IsBusy() && !controlpacket_queue.IsEmpty()) {
        theApp.uploadBandwidthThrottler->QueueForSendingControlPacket(this);
    }
    sendLocker.Unlock();

    SocketSentBytes returnVal = { true, 0, sentBytes };
    return returnVal;
// <-- ZZ:UploadBandWithThrottler (UDP)
}

int CUDPSocket::SendTo(BYTE* lpBuf, int nBufLen, uint32 dwIP, uint16 nPort)
{
	// NOTE: *** This function is invoked from a *different* thread!
	int iResult = CAsyncSocket::SendTo(lpBuf, nBufLen, nPort, ipstr(dwIP));
	if (iResult == SOCKET_ERROR) {
		DWORD dwError = GetLastError();
		if (dwError == WSAEWOULDBLOCK) {
			m_bWouldBlock = true;
			return -1; // blocked
		}
		else{
			if (thePrefs.GetVerbose())
				theApp.QueueDebugLogLine(false, _T("Error: Server UDP socket: Failed to send packet to %s:%u - %s"), ipstr(dwIP), nPort, GetErrorMessage(dwError, 1));
			return 0; // error
		}
	}
	return 1; // success
}

void CUDPSocket::SendBuffer(uint32 nIP, uint16 nPort, BYTE* pPacket, UINT uSize)
{
// ZZ:UploadBandWithThrottler (UDP) -->
	SServerUDPPacket* newpending = new SServerUDPPacket;
	newpending->dwIP = nIP;
	newpending->nPort = nPort;
	newpending->packet = pPacket;
	newpending->size = uSize;
    sendLocker.Lock();
	controlpacket_queue.AddTail(newpending);
    sendLocker.Unlock();
    theApp.uploadBandwidthThrottler->QueueForSendingControlPacket(this);
// <-- ZZ:UploadBandWithThrottler (UDP)
}

void CUDPSocket::SendPacket(Packet* packet, CServer* pServer, uint16 nSpecialPort, BYTE* pInRawPacket, uint32 nRawLen)
{
	// Just for safety.. Ensure that there are no stalled DNS queries and/or packets
	// hanging endlessly in the queue.
	POSITION pos = m_aDNSReqs.GetHeadPosition();
	if (pos) {
		DWORD dwNow = GetTickCount();
		while (pos) {
			POSITION posPrev = pos;
			SServerDNSRequest* pDNSReq = m_aDNSReqs.GetNext(pos);
			if (dwNow - pDNSReq->m_dwCreated >= SEC2MS(60*2)) {
				delete pDNSReq;
				m_aDNSReqs.RemoveAt(posPrev);
			}
		}
	}

	// Create raw UDP packet
	BYTE* pRawPacket;
	UINT uRawPacketSize;
	uint16 nPort = 0;
	if (packet != NULL){
		pRawPacket = new BYTE[packet->size + 2];
		memcpy(pRawPacket, packet->GetUDPHeader(), 2);
		memcpy(pRawPacket + 2, packet->pBuffer, packet->size);
		uRawPacketSize = packet->size + 2;
		if (thePrefs.IsServerCryptLayerUDPEnabled() && pServer->GetServerKeyUDP() != 0 && pServer->SupportsObfuscationUDP()){
			uRawPacketSize = EncryptSendServer(&pRawPacket, uRawPacketSize, pServer->GetServerKeyUDP());
			if (thePrefs.GetDebugServerUDPLevel() > 0)
				DEBUG_ONLY(DebugLog(_T("Sending encrypted packet to server %s, UDPKey %u"), pServer->GetListName(), pServer->GetServerKeyUDP()));
			nPort = pServer->GetObfuscationPortUDP();
		}
		else
			nPort = pServer->GetPort() + 4;
	}
	else if (pInRawPacket != 0){
		// we don't encrypt rawpackets (!)
		pRawPacket = new BYTE[nRawLen];
		memcpy(pRawPacket, pInRawPacket, nRawLen);
		uRawPacketSize = nRawLen;
		nPort = pServer->GetPort() + 4;
	}
	else{
		ASSERT( false );
		return;
	}
	nPort = (nSpecialPort == 0) ? nPort : nSpecialPort;
	ASSERT( nPort != 0 );

	// Do we need to resolve the DN of this server?
	CT2CA pszHostAddressA(pServer->GetAddress());
	uint32 nIP = inet_addr(pszHostAddressA);
	if (nIP == INADDR_NONE)
	{
		// If there is already a DNS query ongoing or queued for this server, append the
		// current packet to this DNS query. The packet(s) will be sent later after the DNS
		// query has completed.
		POSITION pos = m_aDNSReqs.GetHeadPosition();
		while (pos) {
			SServerDNSRequest* pDNSReq = m_aDNSReqs.GetNext(pos);
			if (_stricmp(CStringA(pDNSReq->m_pServer->GetAddress()), pszHostAddressA) == 0) {
				SRawServerPacket* pServerPacket = new SRawServerPacket(pRawPacket, uRawPacketSize, nPort);
				pDNSReq->m_aPackets.AddTail(pServerPacket);
				return;
			}
		}

		// Create a new DNS query for this server
		SServerDNSRequest* pDNSReq = new SServerDNSRequest(0, new CServer(pServer));
		pDNSReq->m_hDNSTask = WSAAsyncGetHostByName(m_hWndResolveMessage, WM_DNSLOOKUPDONE,
								pszHostAddressA, pDNSReq->m_DnsHostBuffer, sizeof pDNSReq->m_DnsHostBuffer);
		if (pDNSReq->m_hDNSTask == NULL) {
			if (thePrefs.GetVerbose())
				DebugLogWarning(_T("Error: Server UDP socket: Failed to resolve address for '%hs' - %s"), pszHostAddressA, GetErrorMessage(GetLastError(), 1));
			delete pDNSReq;
			delete[] pRawPacket;
			return;
		}
		SRawServerPacket* pServerPacket = new SRawServerPacket(pRawPacket, uRawPacketSize, nPort);
		pDNSReq->m_aPackets.AddTail(pServerPacket);
		m_aDNSReqs.AddTail(pDNSReq);
	}
	else
	{
		// No DNS query needed for this server. Just send the packet.
		SendBuffer(nIP, nPort, pRawPacket, uRawPacketSize);
	}
}
