path: root/src/modules/netlib/netlibopenconn.cpp

/*

Miranda IM: the free IM client for Microsoft* Windows*

Copyright 2000-2012 Miranda ICQ/IM project, 
all portions of this codebase are copyrighted to the people 
listed in contributors.txt.

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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/
#include "commonheaders.h"
#include "netlib.h"

extern CRITICAL_SECTION csNetlibUser;
extern HANDLE hConnectionOpenMutex;
extern DWORD g_LastConnectionTick;
extern int connectionTimeout;
static int iUPnPCleanup = 0;

#define RECV_DEFAULT_TIMEOUT	60000

//returns in network byte order
DWORD DnsLookup(struct NetlibUser *nlu,const char *szHost)
{
	HOSTENT* host;
	DWORD ip = inet_addr(szHost);
	if (ip != INADDR_NONE)
		return ip;

	__try 
	{
		host = gethostbyname(szHost);
		if ( host )
			return *(u_long*)host->h_addr_list[0];

		NetlibLogf(nlu,"%s %d: %s() for host %s failed (%u)",__FILE__,__LINE__,"gethostbyname", szHost, WSAGetLastError());
	}
	__except(EXCEPTION_EXECUTE_HANDLER) {}

	return 0;
}

int WaitUntilReadable(SOCKET s, DWORD dwTimeout, bool check)
{
	fd_set readfd;
	TIMEVAL tv;

	if (s == INVALID_SOCKET) return SOCKET_ERROR;

	tv.tv_sec  = dwTimeout / 1000;
	tv.tv_usec = (dwTimeout % 1000) * 1000;

	FD_ZERO(&readfd);
	FD_SET(s, &readfd);

	int result = select(0, &readfd, 0, 0, &tv);
	if (result == 0 && !check) SetLastError(ERROR_TIMEOUT);
	return result;
}

int WaitUntilWritable(SOCKET s,DWORD dwTimeout)
{
	fd_set writefd;
	TIMEVAL tv;

	tv.tv_sec = dwTimeout / 1000;
	tv.tv_usec = (dwTimeout % 1000) * 1000;

	FD_ZERO(&writefd);
	FD_SET(s, &writefd);

	switch(select(0, 0, &writefd, 0, &tv)) 
	{
	case 0:
		SetLastError(ERROR_TIMEOUT);
	case SOCKET_ERROR:
		return 0;
	}
	return 1;
}

bool RecvUntilTimeout(struct NetlibConnection *nlc, char *buf, int len, int flags, DWORD dwTimeout)
{
	int nReceived = 0;
	DWORD dwTimeNow, dwCompleteTime = GetTickCount() + dwTimeout;

	while ((dwTimeNow = GetTickCount()) < dwCompleteTime) 
	{
		if (WaitUntilReadable(nlc->s, dwCompleteTime - dwTimeNow) <= 0) return false; 
		nReceived = NLRecv(nlc, buf, len, flags);
		if (nReceived <= 0) return false;

		buf += nReceived;
		len -= nReceived;
		if (len <= 0) return true;
	}
	SetLastError( ERROR_TIMEOUT );
	return false;
}

static int NetlibInitSocks4Connection(NetlibConnection *nlc, NetlibUser *nlu, NETLIBOPENCONNECTION *nloc)
{	
	//	http://www.socks.nec.com/protocol/socks4.protocol and http://www.socks.nec.com/protocol/socks4a.protocol
	if (!nloc->szHost || !nloc->szHost[0]) return 0;

	size_t nHostLen = strlen(nloc->szHost) + 1;
	size_t nUserLen = nlu->settings.szProxyAuthUser ? strlen(nlu->settings.szProxyAuthUser) + 1 : 1;
	size_t len = 8 + nUserLen;

	char* pInit = (char*)alloca(len + nHostLen);
	pInit[0] = 4;	// SOCKS4
	pInit[1] = 1;	//connect
	*(PWORD)&pInit[2] = htons(nloc->wPort);

	if (nUserLen <= 1) pInit[8] = 0;
	else memcpy(&pInit[8], nlu->settings.szProxyAuthUser, nUserLen);

	//if cannot resolve host, try resolving through proxy (requires SOCKS4a)  
	DWORD ip = DnsLookup(nlu, nloc->szHost);
	*(PDWORD)&pInit[4] = ip ? ip : 0x01000000; 	
	if (!ip) 
	{
		memcpy(&pInit[len], nloc->szHost, nHostLen);
		len += nHostLen;
	}

	if (NLSend(nlc, pInit, (int)len, MSG_DUMPPROXY) == SOCKET_ERROR) 
	{
		NetlibLogf(nlu,"%s %d: %s() failed (%u)",__FILE__,__LINE__,"NLSend",GetLastError());
		return 0;
	}

	char reply[8];
	if (!RecvUntilTimeout(nlc, reply, sizeof(reply), MSG_DUMPPROXY, RECV_DEFAULT_TIMEOUT)) 
	{
		NetlibLogf(nlu,"%s %d: %s() failed (%u)",__FILE__,__LINE__,"RecvUntilTimeout",GetLastError());
		return 0;
	}

	switch ((BYTE)reply[1]) 
	{
	case 90: return 1;
	case 91: SetLastError(ERROR_ACCESS_DENIED); break;
	case 92: SetLastError(ERROR_CONNECTION_UNAVAIL); break;
	case 93: SetLastError(ERROR_INVALID_ACCESS); break;
	default: SetLastError(ERROR_INVALID_DATA); break;
	}
	NetlibLogf(nlu,"%s %d: Proxy connection failed (%x %u)",__FILE__,__LINE__, (BYTE)reply[1], GetLastError());
	return 0;
}

static int NetlibInitSocks5Connection(struct NetlibConnection *nlc,struct NetlibUser *nlu,NETLIBOPENCONNECTION *nloc)
{	//rfc1928
	BYTE buf[258];

	buf[0]=5;  //yep, socks5
	buf[1]=1;  //one auth method
	buf[2]=nlu->settings.useProxyAuth?2:0;
	if(NLSend(nlc,(char*)buf,3,MSG_DUMPPROXY)==SOCKET_ERROR) {
		NetlibLogf(nlu,"%s %d: %s() failed (%u)",__FILE__,__LINE__,"NLSend",GetLastError());
		return 0;
	}

	//confirmation of auth method
	if (!RecvUntilTimeout(nlc,(char*)buf,2,MSG_DUMPPROXY,RECV_DEFAULT_TIMEOUT)) {
		NetlibLogf(nlu,"%s %d: %s() failed (%u)",__FILE__,__LINE__,"RecvUntilTimeout",GetLastError());
		return 0;
	}
	if((buf[1]!=0 && buf[1]!=2)) {
		SetLastError(ERROR_INVALID_ID_AUTHORITY);
		NetlibLogf(nlu,"%s %d: %s() failed (%u)",__FILE__,__LINE__,"NLRecv",GetLastError());
		return 0;
	}

	if(buf[1]==2) {		//rfc1929
		int nUserLen,nPassLen;
		PBYTE pAuthBuf;

		nUserLen=lstrlenA(nlu->settings.szProxyAuthUser);
		nPassLen=lstrlenA(nlu->settings.szProxyAuthPassword);
		pAuthBuf=(PBYTE)mir_alloc(3+nUserLen+nPassLen);
		pAuthBuf[0]=1;		//auth version
		pAuthBuf[1]=nUserLen;
		memcpy(pAuthBuf+2,nlu->settings.szProxyAuthUser,nUserLen);
		pAuthBuf[2+nUserLen]=nPassLen;
		memcpy(pAuthBuf+3+nUserLen,nlu->settings.szProxyAuthPassword,nPassLen);
		if(NLSend(nlc,(char*)pAuthBuf,3+nUserLen+nPassLen,MSG_DUMPPROXY)==SOCKET_ERROR) {
			NetlibLogf(nlu,"%s %d: %s() failed (%u)",__FILE__,__LINE__,"NLSend",GetLastError());
			mir_free(pAuthBuf);
			return 0;
		}
		mir_free(pAuthBuf);

		if (!RecvUntilTimeout(nlc,(char*)buf,2,MSG_DUMPPROXY,RECV_DEFAULT_TIMEOUT)) {
			NetlibLogf(nlu,"%s %d: %s() failed (%u)",__FILE__,__LINE__,"RecvUntilTimeout",GetLastError());
			return 0;
		}
		if(buf[1]) {
			SetLastError(ERROR_ACCESS_DENIED);
			NetlibLogf(nlu,"%s %d: %s() failed (%u)",__FILE__,__LINE__,"RecvUntilTimeout",GetLastError());
			return 0;
		}
	}

	{	
		PBYTE pInit;
		int nHostLen;
		DWORD hostIP;

		if(nlc->dnsThroughProxy) {
			if((hostIP=inet_addr(nloc->szHost))==INADDR_NONE)
				nHostLen=lstrlenA(nloc->szHost)+1;
			else nHostLen=4;
		}
		else {
			if((hostIP=DnsLookup(nlu,nloc->szHost))==0)
				return 0;
			nHostLen=4;
		}
		pInit=(PBYTE)mir_alloc(6+nHostLen);
		pInit[0]=5;   //SOCKS5
		pInit[1]= nloc->flags & NLOCF_UDP ? 3 : 1; //connect or UDP
		pInit[2]=0;   //reserved
		if(hostIP==INADDR_NONE) {		 //DNS lookup through proxy
			pInit[3]=3;
			pInit[4]=nHostLen-1;
			memcpy(pInit+5,nloc->szHost,nHostLen-1);
		}
		else {
			pInit[3]=1;
			*(PDWORD)(pInit+4)=hostIP;
		}
		*(PWORD)(pInit+4+nHostLen)=htons(nloc->wPort);
		if(NLSend(nlc,(char*)pInit,6+nHostLen,MSG_DUMPPROXY)==SOCKET_ERROR) {
			NetlibLogf(nlu,"%s %d: %s() failed (%u)",__FILE__,__LINE__,"NLSend",GetLastError());
			mir_free(pInit);
			return 0;
		}
		mir_free(pInit);
	}

	if (!RecvUntilTimeout(nlc,(char*)buf,5,MSG_DUMPPROXY,RECV_DEFAULT_TIMEOUT)) {
		NetlibLogf(nlu,"%s %d: %s() failed (%u)",__FILE__,__LINE__,"RecvUntilTimeout",GetLastError());
		return 0;
	}

	if ( buf[0]!=5 || buf[1] ) {
		const char* err = "Unknown response"; 
		if ( buf[0] != 5 )
			SetLastError(ERROR_BAD_FORMAT);
		else
		{
			switch(buf[1]) 
			{
			case 1: SetLastError(ERROR_GEN_FAILURE); err = "General failure"; break;
			case 2: SetLastError(ERROR_ACCESS_DENIED); err = "Connection not allowed by ruleset";  break;
			case 3: SetLastError(WSAENETUNREACH); err = "Network unreachable"; break;
			case 4: SetLastError(WSAEHOSTUNREACH); err = "Host unreachable"; break;
			case 5: SetLastError(WSAECONNREFUSED); err = "Connection refused by destination host"; break;
			case 6: SetLastError(WSAETIMEDOUT); err = "TTL expired"; break;
			case 7: SetLastError(ERROR_CALL_NOT_IMPLEMENTED); err = "Command not supported / protocol error"; break;
			case 8: SetLastError(ERROR_INVALID_ADDRESS); err = "Address type not supported"; break;
			default: SetLastError(ERROR_INVALID_DATA); break;
			}
		}
		NetlibLogf(nlu,"%s %d: Proxy conection failed. %s.",__FILE__,__LINE__, err);
		return 0;
	}
	{
		int nRecvSize = 0;
		switch( buf[3] ) {
		case 1:// ipv4 addr
			nRecvSize = 5;
			break;
		case 3:// dns name addr
			nRecvSize = buf[4] + 2;
			break;
		case 4:// ipv6 addr
			nRecvSize = 17;
			break;
		default:
			NetlibLogf(nlu,"%s %d: %s() unknown address type (%u)",__FILE__,__LINE__,"NetlibInitSocks5Connection",(int)buf[3]);
			return 0;
		}
		if (!RecvUntilTimeout(nlc,(char*)buf,nRecvSize,MSG_DUMPPROXY,RECV_DEFAULT_TIMEOUT)) {
			NetlibLogf(nlu,"%s %d: %s() failed (%u)",__FILE__,__LINE__,"RecvUntilTimeout",GetLastError());
			return 0;
		}	
	}

	//connected
	return 1;
}

static bool NetlibInitHttpsConnection(struct NetlibConnection *nlc, struct NetlibUser *nlu, NETLIBOPENCONNECTION *nloc)
{	//rfc2817
	NETLIBHTTPREQUEST nlhrSend = {0}, *nlhrReply;
	char szUrl[512];

	nlhrSend.cbSize = sizeof(nlhrSend);
	nlhrSend.requestType = REQUEST_CONNECT;
	nlhrSend.flags = NLHRF_GENERATEHOST | NLHRF_DUMPPROXY | NLHRF_SMARTAUTHHEADER | NLHRF_HTTP11 | NLHRF_NOPROXY | NLHRF_REDIRECT;
	if (nlc->dnsThroughProxy) 
	{
		mir_snprintf(szUrl, SIZEOF(szUrl), "%s:%u", nloc->szHost, nloc->wPort);
	}
	else 
	{
		DWORD ip = DnsLookup(nlu, nloc->szHost);
		if (ip == 0) return false;
		mir_snprintf(szUrl, SIZEOF(szUrl), "%s:%u", inet_ntoa(*(PIN_ADDR)&ip), nloc->wPort);
	}
	nlhrSend.szUrl = szUrl;

	nlc->usingHttpGateway = true;

	if (NetlibHttpSendRequest((WPARAM)nlc, (LPARAM)&nlhrSend) == SOCKET_ERROR)
	{
		nlc->usingHttpGateway = false;
		return 0;
	}
	nlhrReply = NetlibHttpRecv(nlc, MSG_DUMPPROXY | MSG_RAW, MSG_DUMPPROXY | MSG_RAW, true);
	nlc->usingHttpGateway = false;
	if (nlhrReply == NULL) return false;
	if (nlhrReply->resultCode < 200 || nlhrReply->resultCode >= 300)
	{
		if (nlhrReply->resultCode == 403 && nlc->dnsThroughProxy) 
		{
			NetlibHttpFreeRequestStruct(0, (LPARAM)nlhrReply);
			nlc->dnsThroughProxy = 0;
			return NetlibInitHttpsConnection(nlc, nlu, nloc);
		}

		NetlibHttpSetLastErrorUsingHttpResult(nlhrReply->resultCode);
		NetlibLogf(nlu,"%s %d: %s request failed (%u %s)",__FILE__,__LINE__,nlu->settings.proxyType==PROXYTYPE_HTTP?"HTTP":"HTTPS",nlhrReply->resultCode,nlhrReply->szResultDescr);
		NetlibHttpFreeRequestStruct(0, (LPARAM)nlhrReply);
		return 0;
	}
	NetlibHttpFreeRequestStruct(0, (LPARAM)nlhrReply);
	//connected
	return true;
}

static void FreePartiallyInitedConnection(struct NetlibConnection *nlc)
{
	DWORD dwOriginalLastError=GetLastError();

	if (nlc->s!=INVALID_SOCKET) closesocket(nlc->s);
	mir_free(nlc->nlhpi.szHttpPostUrl);
	mir_free(nlc->nlhpi.szHttpGetUrl);
	mir_free((char*)nlc->nloc.szHost);
	mir_free(nlc->szProxyServer);
	NetlibDeleteNestedCS(&nlc->ncsSend);
	NetlibDeleteNestedCS(&nlc->ncsRecv);
	CloseHandle(nlc->hOkToCloseEvent);
	DeleteCriticalSection(&nlc->csHttpSequenceNums);
	mir_free(nlc);
	SetLastError(dwOriginalLastError);
}

static bool my_connectIPv4(NetlibConnection *nlc, NETLIBOPENCONNECTION * nloc)
{
	int rc = 0, retrycnt = 0;
	u_long notblocking = 1;	
	DWORD lasterr = 0;	
	static const TIMEVAL tv = { 1, 0 };

	unsigned int dwTimeout = (nloc->cbSize == sizeof(NETLIBOPENCONNECTION) && nloc->flags & NLOCF_V2) ? nloc->timeout : 0;
	// if dwTimeout is zero then its an old style connection or new with a 0 timeout, select() will error quicker anyway
	if (dwTimeout == 0) dwTimeout = 30;

	// this is for XP SP2 where there is a default connection attempt limit of 10/second
	if (connectionTimeout)
	{
		WaitForSingleObject(hConnectionOpenMutex, 10000);
		int waitdiff = GetTickCount() - g_LastConnectionTick;
		if (waitdiff < connectionTimeout) SleepEx(connectionTimeout, TRUE);
		g_LastConnectionTick = GetTickCount();
		ReleaseMutex(hConnectionOpenMutex);

		// might of died in between the wait
		if (Miranda_Terminated()) return false;
	}

    SOCKADDR_IN sin = {0};
   	sin.sin_family = AF_INET;

	if (nlc->proxyType)
	{
		if (!nlc->szProxyServer) return false;

		if (nloc)
			NetlibLogf(nlc->nlu,"(%p) Connecting to proxy %s:%d for %s:%d ....", nlc, nlc->szProxyServer, nlc->wProxyPort, nloc->szHost, nloc->wPort);
		else
			NetlibLogf(nlc->nlu,"(%p) Connecting to proxy %s:%d ....", nlc, nlc->szProxyServer, nlc->wProxyPort);
		
		sin.sin_port = htons(nlc->wProxyPort);
		sin.sin_addr.s_addr = DnsLookup(nlc->nlu, nlc->szProxyServer);
	}
	else
	{
		if (!nloc || !nloc->szHost) return false;
		NetlibLogf(nlc->nlu,"(%p) Connecting to server %s:%d....", nlc, nloc->szHost, nloc->wPort);

		sin.sin_port = htons(nloc->wPort);
		sin.sin_addr.s_addr = DnsLookup(nlc->nlu, nloc->szHost);
	}

retry:
	nlc->s = socket(AF_INET,nloc->flags & NLOCF_UDP ? SOCK_DGRAM : SOCK_STREAM, 0);
	if (nlc->s == INVALID_SOCKET) return false;

	// return the socket to non blocking
	if (ioctlsocket(nlc->s, FIONBIO, &notblocking) != 0) return false;

	if (nlc->nlu->settings.specifyOutgoingPorts && nlc->nlu->settings.szOutgoingPorts  && nlc->nlu->settings.szOutgoingPorts[0]) 
	{
		if (!BindSocketToPort(nlc->nlu->settings.szOutgoingPorts, nlc->s, &nlc->nlu->inportnum))
			NetlibLogf(nlc->nlu,"Netlib connect: Not enough ports for outgoing connections specified");
	} 

	// try a connect
	if (connect(nlc->s, (LPSOCKADDR)&sin, sizeof(sin)) == 0) 
	{
		goto unblock;
	}

	// didn't work, was it cos of nonblocking?
	if (WSAGetLastError() != WSAEWOULDBLOCK) 
	{
		rc = SOCKET_ERROR;
		goto unblock;
	}

	for (;;) 
	{		
		fd_set r, w, e;
		FD_ZERO(&r); FD_ZERO(&w); FD_ZERO(&e);
		FD_SET(nlc->s, &r);
		FD_SET(nlc->s, &w);
		FD_SET(nlc->s, &e);		
		if ((rc = select(0, &r, &w, &e, &tv)) == SOCKET_ERROR) 
			break;

		if (rc > 0) 
		{			
			if (FD_ISSET(nlc->s, &w))
			{
				// connection was successful
				rc = 0;
			}
			if (FD_ISSET(nlc->s, &r)) 
			{
				// connection was closed
				rc = SOCKET_ERROR;
				lasterr = WSAECONNRESET;
			}
			if (FD_ISSET(nlc->s, &e)) 
			{
				// connection failed.
				int len = sizeof(lasterr);
				rc = SOCKET_ERROR;
				getsockopt(nlc->s, SOL_SOCKET, SO_ERROR, (char*)&lasterr, &len);
				if (lasterr == WSAEADDRINUSE && ++retrycnt <= 2) 
				{
					closesocket(nlc->s);
					goto retry;
				}
			}
			break;
		} 
		else if (Miranda_Terminated()) 
		{
			rc = SOCKET_ERROR;
			lasterr = ERROR_TIMEOUT;
			break;
		} 
		else if (nloc->cbSize == sizeof(NETLIBOPENCONNECTION) && nloc->flags & NLOCF_V2 && 
			nloc->waitcallback != NULL && nloc->waitcallback(&dwTimeout) == 0)
		{
			rc = SOCKET_ERROR;
			lasterr = ERROR_TIMEOUT;
			break;
		}
		if (--dwTimeout == 0) 
		{
			rc = SOCKET_ERROR;
			lasterr = ERROR_TIMEOUT;
			break;
		}
	}

unblock:	
	notblocking = 0;
	ioctlsocket(nlc->s, FIONBIO, &notblocking);
	if (lasterr) SetLastError(lasterr);
	return rc == 0;
}

static bool my_connectIPv6(NetlibConnection *nlc, NETLIBOPENCONNECTION * nloc)
{
	int rc = SOCKET_ERROR, retrycnt = 0;
	u_long notblocking = 1;	
	DWORD lasterr = 0;	
	static const TIMEVAL tv = { 1, 0 };

	unsigned int dwTimeout = (nloc->cbSize == sizeof(NETLIBOPENCONNECTION) && nloc->flags & NLOCF_V2) ? nloc->timeout : 0;
	// if dwTimeout is zero then its an old style connection or new with a 0 timeout, select() will error quicker anyway
	if (dwTimeout == 0) dwTimeout = 30;

	// this is for XP SP2 where there is a default connection attempt limit of 10/second
	if (connectionTimeout)
	{
		WaitForSingleObject(hConnectionOpenMutex, 10000);
		int waitdiff = GetTickCount() - g_LastConnectionTick;
		if (waitdiff < connectionTimeout) SleepEx(connectionTimeout, TRUE);
		g_LastConnectionTick = GetTickCount();
		ReleaseMutex(hConnectionOpenMutex);

		// might of died in between the wait
		if (Miranda_Terminated()) return false;
	}

	char szPort[6];
	addrinfo *air = NULL, *ai, hints = {0};

	hints.ai_family = AF_UNSPEC;

	if (nloc->flags & NLOCF_UDP)
	{
		hints.ai_socktype = SOCK_DGRAM;
		hints.ai_protocol = IPPROTO_UDP;
	}
	else
	{
		hints.ai_socktype = SOCK_STREAM;
		hints.ai_protocol = IPPROTO_TCP;
	}
	
	if (nlc->proxyType)
	{
		if (!nlc->szProxyServer) return false;

		if (nloc)
			NetlibLogf(nlc->nlu,"(%p) Connecting to proxy %s:%d for %s:%d ....", nlc, nlc->szProxyServer, nlc->wProxyPort, nloc->szHost, nloc->wPort);
		else
			NetlibLogf(nlc->nlu,"(%p) Connecting to proxy %s:%d ....", nlc, nlc->szProxyServer, nlc->wProxyPort);

		_itoa(nlc->wProxyPort, szPort, 10);
		if (MyGetaddrinfo(nlc->szProxyServer, szPort, &hints, &air))
		{
			NetlibLogf(nlc->nlu,"%s %d: %s() for host %s failed (%u)",__FILE__,__LINE__,"getaddrinfo", nlc->szProxyServer, WSAGetLastError());
			return false;
		}
	}
	else
	{
		if (!nloc || !nloc->szHost) return false;
		NetlibLogf(nlc->nlu,"(%p) Connecting to server %s:%d....", nlc, nloc->szHost, nloc->wPort);

		_itoa(nlc->nloc.wPort, szPort, 10);

		if (MyGetaddrinfo(nlc->nloc.szHost, szPort, &hints, &air))
		{
			NetlibLogf(nlc->nlu,"%s %d: %s() for host %s failed (%u)",__FILE__,__LINE__,"getaddrinfo", nlc->nloc.szHost, WSAGetLastError());
			return false;
		}
	}

    for (ai = air; ai && !Miranda_Terminated(); ai = ai->ai_next)
	{
retry:
		nlc->s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
		if (nlc->s == INVALID_SOCKET) return false;

		// return the socket to non blocking
		if (ioctlsocket(nlc->s, FIONBIO, &notblocking) != 0) return false;

		if (nlc->nlu->settings.specifyOutgoingPorts && nlc->nlu->settings.szOutgoingPorts  && nlc->nlu->settings.szOutgoingPorts[0]) 
		{
			if (!BindSocketToPort(nlc->nlu->settings.szOutgoingPorts, nlc->s, &nlc->nlu->inportnum))
				NetlibLogf(nlc->nlu,"Netlib connect: Not enough ports for outgoing connections specified");
		} 

		// try a connect
		if (connect(nlc->s, ai->ai_addr, (int)ai->ai_addrlen) == 0) 
		{
			rc = 0;
			break;
		}

		// didn't work, was it cos of nonblocking?
		if (WSAGetLastError() != WSAEWOULDBLOCK) 
		{
			rc = SOCKET_ERROR;
			break;
		}

		for (;;) // timeout loop 
		{		
			fd_set r, w, e;
			FD_ZERO(&r); FD_ZERO(&w); FD_ZERO(&e);
			FD_SET(nlc->s, &r);
			FD_SET(nlc->s, &w);
			FD_SET(nlc->s, &e);		
			if ((rc = select(0, &r, &w, &e, &tv)) == SOCKET_ERROR) 
				break;

			if (rc > 0) 
			{			
				if (FD_ISSET(nlc->s, &w))
				{
					// connection was successful
					rc = 0;
					lasterr = 0;
				}
				if (FD_ISSET(nlc->s, &r)) 
				{
					// connection was closed
					rc = SOCKET_ERROR;
					lasterr = WSAECONNRESET;
				}
				if (FD_ISSET(nlc->s, &e)) 
				{
					// connection failed.
					int len = sizeof(lasterr);
					rc = SOCKET_ERROR;
					getsockopt(nlc->s, SOL_SOCKET, SO_ERROR, (char*)&lasterr, &len);
					if (lasterr == WSAEADDRINUSE && ++retrycnt <= 2) 
					{
						closesocket(nlc->s);
						nlc->s = INVALID_SOCKET;
						goto retry;
					}
				}
				break;
			} 
			else if (Miranda_Terminated()) 
			{
				rc = SOCKET_ERROR;
				lasterr = ERROR_TIMEOUT;
				break;
			} 
			else if (nloc->cbSize == sizeof(NETLIBOPENCONNECTION) && nloc->flags & NLOCF_V2 && 
				nloc->waitcallback != NULL && nloc->waitcallback(&dwTimeout) == 0)
			{
				rc = SOCKET_ERROR;
				lasterr = ERROR_TIMEOUT;
				break;
			}
			if (--dwTimeout == 0) 
			{
				rc = SOCKET_ERROR;
				lasterr = ERROR_TIMEOUT;
				break;
			}
		}

		if (rc == 0) break;

		closesocket(nlc->s);
		nlc->s = INVALID_SOCKET;
	}

	MyFreeaddrinfo(air);

	notblocking = 0;
	if (nlc->s != INVALID_SOCKET) ioctlsocket(nlc->s, FIONBIO, &notblocking);
	if (rc && lasterr) SetLastError(lasterr);
	return rc == 0;
}

static bool my_connect(NetlibConnection *nlc, NETLIBOPENCONNECTION * nloc)
{
	return MyGetaddrinfo && MyFreeaddrinfo ? my_connectIPv6(nlc, nloc) : my_connectIPv4(nlc, nloc);
}

static int NetlibHttpFallbackToDirect(struct NetlibConnection *nlc, struct NetlibUser *nlu, NETLIBOPENCONNECTION *nloc)
{
	NetlibDoClose(nlc, true);

	NetlibLogf(nlu,"Fallback to direct connection");

	nlc->proxyAuthNeeded = false;
	nlc->proxyType = 0;
	mir_free(nlc->szProxyServer); nlc->szProxyServer = NULL;
	if (!my_connect(nlc, nloc)) 
	{
		NetlibLogf(nlu, "%s %d: %s() failed (%u)", __FILE__, __LINE__, "connect", WSAGetLastError());
		return false;
	}
	return true;
}

bool NetlibDoConnect(NetlibConnection *nlc)
{
	NETLIBOPENCONNECTION *nloc = &nlc->nloc;
	NetlibUser *nlu = nlc->nlu;

	mir_free(nlc->szProxyServer); nlc->szProxyServer = NULL;

	bool usingProxy = false, forceHttps = false;
	if (nlu->settings.useProxy)
	{
		if (nlu->settings.proxyType == PROXYTYPE_IE)
		{
			usingProxy = NetlibGetIeProxyConn(nlc, false);
		}
		else
		{
			if (nlu->settings.szProxyServer && nlu->settings.szProxyServer[0])
			{
				nlc->szProxyServer = mir_strdup(nlu->settings.szProxyServer);
				nlc->wProxyPort = nlu->settings.wProxyPort;
				nlc->proxyType = nlu->settings.proxyType;
				usingProxy = true;
			}
		}
	}

retry:
	if (usingProxy) 
	{
		if (!my_connect(nlc, nloc)) 
		{
			usingProxy = false;
			nlc->proxyType = 0;
		}
	}
	if (!usingProxy)
	{
		my_connect(nlc, nloc);
	}

	if (nlc->s == INVALID_SOCKET) 
	{
		if (usingProxy && (nlc->proxyType == PROXYTYPE_HTTPS || nlc->proxyType == PROXYTYPE_HTTP))
		{
			usingProxy = false;
			if (!NetlibHttpFallbackToDirect(nlc, nlu, nloc))
			{
				NetlibLogf(nlu, "%s %d: %s() failed (%u)", __FILE__, __LINE__, "connect", WSAGetLastError());
				return false;
			}
		}
		else
		{
			if (nlu->settings.useProxy && !usingProxy && nlu->settings.proxyType == PROXYTYPE_IE && !forceHttps)
			{
				forceHttps = true;
				usingProxy = NetlibGetIeProxyConn(nlc, true);
				if (usingProxy) goto retry;
			}
			NetlibLogf(nlu, "%s %d: %s() failed (%u)", __FILE__, __LINE__, "connect", WSAGetLastError());
			return false;
		}
	}

	if (usingProxy && !((nloc->flags & (NLOCF_HTTP | NLOCF_SSL)) == NLOCF_HTTP && 
		(nlc->proxyType == PROXYTYPE_HTTP || nlc->proxyType == PROXYTYPE_HTTPS)))
	{
		if (!WaitUntilWritable(nlc->s, 30000)) return false;

		switch (nlc->proxyType) 
		{
		case PROXYTYPE_SOCKS4:
			if (!NetlibInitSocks4Connection(nlc, nlu, nloc)) return false;
			break;

		case PROXYTYPE_SOCKS5:
			if (!NetlibInitSocks5Connection(nlc, nlu, nloc)) return false;
			break;

		case PROXYTYPE_HTTPS:
			nlc->proxyAuthNeeded = true;
			if (!NetlibInitHttpsConnection(nlc, nlu, nloc))
			{
				usingProxy = false;
				if (!NetlibHttpFallbackToDirect(nlc, nlu, nloc))
					return false;
			}
			break;

		case PROXYTYPE_HTTP:
			nlc->proxyAuthNeeded = true;
			if (!(nlu->user.flags & NUF_HTTPGATEWAY || nloc->flags & NLOCF_HTTPGATEWAY) || nloc->flags & NLOCF_SSL)
			{
				//NLOCF_HTTP not specified and no HTTP gateway available: try HTTPS
				if (!NetlibInitHttpsConnection(nlc, nlu, nloc))
				{
					//can't do HTTPS: try direct
					usingProxy = false;
					if (!NetlibHttpFallbackToDirect(nlc, nlu, nloc))
						return false;
				}
			}
			else 
			{
				if (!NetlibInitHttpConnection(nlc, nlu, nloc)) return false;
			}
			break;

		default:
			SetLastError(ERROR_INVALID_PARAMETER);
			FreePartiallyInitedConnection(nlc);
			return false;
		}
	}
	else if (nloc->flags & NLOCF_HTTPGATEWAY)
	{
		if (!NetlibInitHttpConnection(nlc, nlu, nloc)) return false;
		nlc->usingDirectHttpGateway = true;
	}

	NetlibLogf(nlu,"(%d) Connected to %s:%d", nlc->s, nloc->szHost, nloc->wPort);

	if (NLOCF_SSL & nloc->flags)
	{
		return NetlibStartSsl((WPARAM)nlc, 0) != 0;
	}

	return true;
}

bool NetlibReconnect(NetlibConnection *nlc)
{
	char buf[4];
	bool opened = nlc->s != INVALID_SOCKET;  

	if (opened)
	{
		switch (WaitUntilReadable(nlc->s, 0, true))
		{
		case SOCKET_ERROR:
			opened = false;
			break;

		case 0:
			opened = true;
			break;

		case 1:
			opened = recv(nlc->s, buf, 1, MSG_PEEK) > 0;
			break;
		}

		if (!opened)
			NetlibDoClose(nlc, true);
	}

	if (!opened)
	{
		if (Miranda_Terminated()) return false;
		if (nlc->usingHttpGateway)
		{
			nlc->proxyAuthNeeded = true;
			return my_connect(nlc, &nlc->nloc);
		}
		else
			return NetlibDoConnect(nlc);
	}
	return true;
}

INT_PTR NetlibOpenConnection(WPARAM wParam,LPARAM lParam)
{
	NETLIBOPENCONNECTION *nloc = (NETLIBOPENCONNECTION*)lParam;
	struct NetlibUser *nlu = (struct NetlibUser*)wParam;
	struct NetlibConnection *nlc;

	NetlibLogf(nlu,"Connection request to %s:%d (Flags %x)....", nloc->szHost, nloc->wPort, nloc->flags);

	if (GetNetlibHandleType(nlu) != NLH_USER || !(nlu->user.flags & NUF_OUTGOING) || nloc == NULL ||
		(nloc->cbSize != NETLIBOPENCONNECTION_V1_SIZE && nloc->cbSize != sizeof(NETLIBOPENCONNECTION)) || 
		nloc->szHost == NULL || nloc->wPort == 0)
	{
		SetLastError(ERROR_INVALID_PARAMETER);
		return 0;
	}
	nlc = (struct NetlibConnection*)mir_calloc(sizeof(struct NetlibConnection));
	nlc->handleType = NLH_CONNECTION;
	nlc->nlu = nlu;
	nlc->nloc = *nloc;
	nlc->nloc.szHost = mir_strdup(nloc->szHost);
	nlc->s = INVALID_SOCKET;
	nlc->s2 = INVALID_SOCKET;
	nlc->dnsThroughProxy = nlu->settings.dnsThroughProxy != 0;

	InitializeCriticalSection(&nlc->csHttpSequenceNums);
	nlc->hOkToCloseEvent = CreateEvent(NULL,TRUE,TRUE,NULL);
	nlc->dontCloseNow = 0;
	NetlibInitializeNestedCS(&nlc->ncsSend);
	NetlibInitializeNestedCS(&nlc->ncsRecv);

	if (!NetlibDoConnect(nlc))
	{
		FreePartiallyInitedConnection(nlc);		
		return 0;
	}

	if (iUPnPCleanup == 0)
	{
		EnterCriticalSection(&csNetlibUser);
		if (iUPnPCleanup == 0) 
		{
			iUPnPCleanup = 1;
			forkthread(NetlibUPnPCleanup, 0, NULL);
		}
		LeaveCriticalSection(&csNetlibUser);
	}

	return (INT_PTR)nlc;
}

INT_PTR NetlibStartSsl(WPARAM wParam, LPARAM lParam)
{
	NetlibConnection *nlc = (NetlibConnection*)wParam;
	if (nlc == NULL) return 0;

	NETLIBSSL *sp = (NETLIBSSL*)lParam;
	const char *szHost = sp ? sp->host : nlc->nloc.szHost;

	NetlibLogf(nlc->nlu, "(%d %s) Starting SSL negotiation", nlc->s, szHost);
	nlc->hSsl = si.connect(nlc->s, szHost, nlc->nlu->settings.validateSSL);

	if (nlc->hSsl == NULL)
		NetlibLogf(nlc->nlu,"(%d %s) Failure to negotiate SSL connection", nlc->s, szHost);
	else
		NetlibLogf(nlc->nlu, "(%d %s) SSL negotiation successful", nlc->s, szHost);

	return nlc->hSsl != NULL;
}