api.cpp

/*****************************************************************************
Copyright (c) 2001 - 2011, The Board of Trustees of the University of Illinois.
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

* Redistributions of source code must retain the above
  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the
  above copyright notice, this list of conditions
  and the following disclaimer in the documentation
  and/or other materials provided with the distribution.

* Neither the name of the University of Illinois
  nor the names of its contributors may be used to
  endorse or promote products derived from this
  software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*****************************************************************************/

/*****************************************************************************
written by
   Yunhong Gu, last updated 07/09/2011
*****************************************************************************/

#ifdef WIN32
   #include <winsock2.h>
   #include <ws2tcpip.h>
   #ifdef LEGACY_WIN32
      #include <wspiapi.h>
   #endif
#else
   #include <unistd.h>
#endif
#include <cstring>
#include "api.h"
#include "core.h"

using namespace std;

CUDTSocket::CUDTSocket():
m_Status(INIT),
m_TimeStamp(0),
m_iIPversion(0),
m_pSelfAddr(NULL),
m_pPeerAddr(NULL),
m_SocketID(0),
m_ListenSocket(0),
m_PeerID(0),
m_iISN(0),
m_pUDT(NULL),
m_pQueuedSockets(NULL),
m_pAcceptSockets(NULL),
m_AcceptCond(),
m_AcceptLock(),
m_uiBackLog(0),
m_iMuxID(-1)
{

}

CUDTSocket::~CUDTSocket()
{
   if (AF_INET == m_iIPversion)
   {
      delete (sockaddr_in*)m_pSelfAddr;
      delete (sockaddr_in*)m_pPeerAddr;
   }
   else
   {
      delete (sockaddr_in6*)m_pSelfAddr;
      delete (sockaddr_in6*)m_pPeerAddr;
   }

   delete m_pUDT;
   m_pUDT = NULL;

   delete m_pQueuedSockets;
   delete m_pAcceptSockets;

}

////////////////////////////////////////////////////////////////////////////////

CUDTUnited::CUDTUnited():
m_Sockets(),
m_ControlLock(),
m_IDLock(),
m_SocketID(0),
m_TLSError(),
m_mMultiplexer(),
m_MultiplexerLock(),
m_pCache(NULL),
m_bClosing(false),
m_GCStopLock(),
m_GCStopCond(),
m_InitLock(),
m_iInstanceCount(0),
m_bGCStatus(false),
m_GCThread(),
m_ClosedSockets()
{
   // Socket ID MUST start from a random value
   srand((unsigned int)CTimer::getTime());
   m_SocketID = 1 + (int)((1 << 30) * (double(rand()) / RAND_MAX));

   #ifndef WIN32
      pthread_key_create(&m_TLSError, TLSDestroy);
   #else
      m_TLSError = TlsAlloc();
   #endif

   m_pCache = new CCache<CInfoBlock>;
}

CUDTUnited::~CUDTUnited()
{

   #ifndef WIN32
      pthread_key_delete(m_TLSError);
   #else
      TlsFree(m_TLSError);
   #endif

   delete m_pCache;
}

int CUDTUnited::startup()
{
   CGuard gcinit(m_InitLock);

   if (m_iInstanceCount++ > 0)
      return 0;

   // Global initialization code
   #ifdef WIN32
      WORD wVersionRequested;
      WSADATA wsaData;
      wVersionRequested = MAKEWORD(2, 2);

      if (0 != WSAStartup(wVersionRequested, &wsaData))
         throw CUDTException(1, 0,  WSAGetLastError());
   #endif

   //init CTimer::EventLock

   if (m_bGCStatus)
      return true;

   m_bClosing = false;

   m_GCThread = std::thread(garbageCollect,this);

   m_bGCStatus = true;

   return 0;
}

int CUDTUnited::cleanup()
{
   CGuard gcinit(m_InitLock);

   if (--m_iInstanceCount > 0)
      return 0;

   //destroy CTimer::EventLock

   if (!m_bGCStatus)
      return 0;

   m_bClosing = true;

   m_GCStopCond.notify_one();
   m_GCThread.join();

   m_bGCStatus = false;

   // Global destruction code
   #ifdef WIN32
      WSACleanup();
   #endif

   return 0;
}

UDTSOCKET CUDTUnited::newSocket(int af, int type)
{
   if ((type != SOCK_STREAM) && (type != SOCK_DGRAM))
      throw CUDTException(5, 3, 0);

   CUDTSocket* ns = NULL;

   try
   {
      ns = new CUDTSocket;
      ns->m_pUDT = new CUDT;
      if (AF_INET == af)
      {
         ns->m_pSelfAddr = (sockaddr*)(new sockaddr_in);
         ((sockaddr_in*)(ns->m_pSelfAddr))->sin_port = 0;
      }
      else
      {
         ns->m_pSelfAddr = (sockaddr*)(new sockaddr_in6);
         ((sockaddr_in6*)(ns->m_pSelfAddr))->sin6_port = 0;
      }
   }
   catch (...)
   {
      delete ns;
      throw CUDTException(3, 2, 0);
   }

   CGuard::enterCS(m_IDLock);
   ns->m_SocketID = -- m_SocketID;
   CGuard::leaveCS(m_IDLock);

   ns->m_Status = INIT;
   ns->m_ListenSocket = 0;
   ns->m_pUDT->m_SocketID = ns->m_SocketID;
   ns->m_pUDT->m_iSockType = (SOCK_STREAM == type) ? UDT_STREAM : UDT_DGRAM;
   ns->m_pUDT->m_iIPversion = ns->m_iIPversion = af;
   ns->m_pUDT->m_pCache = m_pCache;

   // protect the m_Sockets structure.
   CGuard::enterCS(m_ControlLock);
   try
   {
      m_Sockets[ns->m_SocketID] = ns;
   }
   catch (...)
   {
      //failure and rollback
      CGuard::leaveCS(m_ControlLock);
      delete ns;
      ns = NULL;
   }
   CGuard::leaveCS(m_ControlLock);

   if (NULL == ns)
      throw CUDTException(3, 2, 0);

   return ns->m_SocketID;
}

int CUDTUnited::newConnection(const UDTSOCKET listen, const sockaddr* peer, CHandShake* hs)
{
   CUDTSocket* ns = NULL;
   CUDTSocket* ls = locate(listen);

   if (NULL == ls)
      return -1;

   // if this connection has already been processed
   if (NULL != (ns = locate(peer, hs->m_iID, hs->m_iISN)))
   {
      if (ns->m_pUDT->m_bBroken)
      {
         // last connection from the "peer" address has been broken
         ns->m_Status = CLOSED;
         ns->m_TimeStamp = CTimer::getTime();

         CGuard::enterCS(ls->m_AcceptLock);
         ls->m_pQueuedSockets->erase(ns->m_SocketID);
         ls->m_pAcceptSockets->erase(ns->m_SocketID);
         CGuard::leaveCS(ls->m_AcceptLock);
      }
      else
      {
         // connection already exist, this is a repeated connection request
         // respond with existing HS information

         hs->m_iISN = ns->m_pUDT->m_iISN;
         hs->m_iMSS = ns->m_pUDT->m_iMSS;
         hs->m_iFlightFlagSize = ns->m_pUDT->m_iFlightFlagSize;
         hs->m_iReqType = -1;
         hs->m_iID = ns->m_SocketID;

         return 0;

         //except for this situation a new connection should be started
      }
   }

   // exceeding backlog, refuse the connection request
   if (ls->m_pQueuedSockets->size() >= ls->m_uiBackLog)
      return -1;

   try
   {
      ns = new CUDTSocket;
      ns->m_pUDT = new CUDT(*(ls->m_pUDT));
      if (AF_INET == ls->m_iIPversion)
      {
         ns->m_pSelfAddr = (sockaddr*)(new sockaddr_in);
         ((sockaddr_in*)(ns->m_pSelfAddr))->sin_port = 0;
         ns->m_pPeerAddr = (sockaddr*)(new sockaddr_in);
         memcpy(ns->m_pPeerAddr, peer, sizeof(sockaddr_in));
      }
      else
      {
         ns->m_pSelfAddr = (sockaddr*)(new sockaddr_in6);
         ((sockaddr_in6*)(ns->m_pSelfAddr))->sin6_port = 0;
         ns->m_pPeerAddr = (sockaddr*)(new sockaddr_in6);
         memcpy(ns->m_pPeerAddr, peer, sizeof(sockaddr_in6));
      }
   }
   catch (...)
   {
      delete ns;
      return -1;
   }

   CGuard::enterCS(m_IDLock);
   ns->m_SocketID = -- m_SocketID;
   CGuard::leaveCS(m_IDLock);

   ns->m_ListenSocket = listen;
   ns->m_iIPversion = ls->m_iIPversion;
   ns->m_pUDT->m_SocketID = ns->m_SocketID;
   ns->m_PeerID = hs->m_iID;
   ns->m_iISN = hs->m_iISN;

   int error = 0;

   try
   {
      // bind to the same addr of listening socket
      ns->m_pUDT->open();
      updateMux(ns, ls);
      ns->m_pUDT->connect(peer, hs);
   }
   catch (...)
   {
      error = 1;
      goto ERR_ROLLBACK;
   }

   ns->m_Status = CONNECTED;

   // copy address information of local node
   ns->m_pUDT->m_pSndQueue->m_pChannel->getSockAddr(ns->m_pSelfAddr);
   CIPAddress::pton(ns->m_pSelfAddr, ns->m_pUDT->m_piSelfIP, ns->m_iIPversion);

   // protect the m_Sockets structure.
   CGuard::enterCS(m_ControlLock);
   try
   {
      m_Sockets[ns->m_SocketID] = ns;
      m_PeerRec[(ns->m_PeerID << 30) + ns->m_iISN].insert(ns->m_SocketID);
   }
   catch (...)
   {
      error = 2;
   }
   CGuard::leaveCS(m_ControlLock);

   CGuard::enterCS(ls->m_AcceptLock);
   try
   {
      ls->m_pQueuedSockets->insert(ns->m_SocketID);
   }
   catch (...)
   {
      error = 3;
   }
   CGuard::leaveCS(ls->m_AcceptLock);

   // acknowledge users waiting for new connections on the listening socket
   m_EPoll.update_events(listen, ls->m_pUDT->m_sPollID, UDT_EPOLL_IN, true);

   CTimer::triggerEvent();

   ERR_ROLLBACK:
   if (error > 0)
   {
      ns->m_pUDT->close();
      ns->m_Status = CLOSED;
      ns->m_TimeStamp = CTimer::getTime();

      return -1;
   }

   // wake up a waiting accept() call
   ls->m_AcceptLock.lock();
   ls->m_AcceptCond.notify_one();
   ls->m_AcceptLock.unlock();

   return 1;
}

CUDT* CUDTUnited::lookup(const UDTSOCKET u)
{
   // protects the m_Sockets structure
   CGuard cg(m_ControlLock);

   map<UDTSOCKET, CUDTSocket*>::iterator i = m_Sockets.find(u);

   if ((i == m_Sockets.end()) || (i->second->m_Status == CLOSED))
      throw CUDTException(5, 4, 0);

   return i->second->m_pUDT;
}

UDTSTATUS CUDTUnited::getStatus(const UDTSOCKET u)
{
   // protects the m_Sockets structure
   CGuard cg(m_ControlLock);

   map<UDTSOCKET, CUDTSocket*>::iterator i = m_Sockets.find(u);

   if (i == m_Sockets.end())
   {
      if (m_ClosedSockets.find(u) != m_ClosedSockets.end())
         return CLOSED;

      return NONEXIST;
   }

   if (i->second->m_pUDT->m_bBroken)
      return BROKEN;

   return i->second->m_Status;   
}

int CUDTUnited::bind(const UDTSOCKET u, const sockaddr* name, int namelen)
{
   CUDTSocket* s = locate(u);
   if (NULL == s)
      throw CUDTException(5, 4, 0);

   CGuard cg(s->m_ControlLock);

   // cannot bind a socket more than once
   if (INIT != s->m_Status)
      throw CUDTException(5, 0, 0);

   // check the size of SOCKADDR structure
   if (AF_INET == s->m_iIPversion)
   {
      if (namelen != sizeof(sockaddr_in))
         throw CUDTException(5, 3, 0);
   }
   else
   {
      if (namelen != sizeof(sockaddr_in6))
         throw CUDTException(5, 3, 0);
   }

   s->m_pUDT->open();
   updateMux(s, name);
   s->m_Status = OPENED;

   // copy address information of local node
   s->m_pUDT->m_pSndQueue->m_pChannel->getSockAddr(s->m_pSelfAddr);

   return 0;
}

int CUDTUnited::bind(UDTSOCKET u, UDPSOCKET udpsock)
{
   CUDTSocket* s = locate(u);
   if (NULL == s)
      throw CUDTException(5, 4, 0);

   CGuard cg(s->m_ControlLock);

   // cannot bind a socket more than once
   if (INIT != s->m_Status)
      throw CUDTException(5, 0, 0);

   sockaddr_in name4;
   sockaddr_in6 name6;
   sockaddr* name;
   socklen_t namelen;

   if (AF_INET == s->m_iIPversion)
   {
      namelen = sizeof(sockaddr_in);
      name = (sockaddr*)&name4;
   }
   else
   {
      namelen = sizeof(sockaddr_in6);
      name = (sockaddr*)&name6;
   }

   if (-1 == ::getsockname(udpsock, name, &namelen))
      throw CUDTException(5, 3);

   s->m_pUDT->open();
   updateMux(s, name, &udpsock);
   s->m_Status = OPENED;

   // copy address information of local node
   s->m_pUDT->m_pSndQueue->m_pChannel->getSockAddr(s->m_pSelfAddr);

   return 0;
}

int CUDTUnited::listen(const UDTSOCKET u, int backlog)
{
   CUDTSocket* s = locate(u);
   if (NULL == s)
      throw CUDTException(5, 4, 0);

   CGuard cg(s->m_ControlLock);

   // do nothing if the socket is already listening
   if (LISTENING == s->m_Status)
      return 0;

   // a socket can listen only if is in OPENED status
   if (OPENED != s->m_Status)
      throw CUDTException(5, 5, 0);

   // listen is not supported in rendezvous connection setup
   if (s->m_pUDT->m_bRendezvous)
      throw CUDTException(5, 7, 0);

   if (backlog <= 0)
      throw CUDTException(5, 3, 0);

   s->m_uiBackLog = backlog;

   try
   {
      s->m_pQueuedSockets = new set<UDTSOCKET>;
      s->m_pAcceptSockets = new set<UDTSOCKET>;
   }
   catch (...)
   {
      delete s->m_pQueuedSockets;
      delete s->m_pAcceptSockets;
      throw CUDTException(3, 2, 0);
   }

   s->m_pUDT->listen();

   s->m_Status = LISTENING;

   return 0;
}

UDTSOCKET CUDTUnited::accept(const UDTSOCKET listen, sockaddr* addr, int* addrlen)
{
   if ((NULL != addr) && (NULL == addrlen))
      throw CUDTException(5, 3, 0);

   CUDTSocket* ls = locate(listen);

   if (ls == NULL)
      throw CUDTException(5, 4, 0);

   // the "listen" socket must be in LISTENING status
   if (LISTENING != ls->m_Status)
      throw CUDTException(5, 6, 0);

   // no "accept" in rendezvous connection setup
   if (ls->m_pUDT->m_bRendezvous)
      throw CUDTException(5, 7, 0);

   UDTSOCKET u = CUDT::INVALID_SOCK;
   bool accepted = false;

   // !!only one conection can be set up each time!!
    while (!accepted)
    {
		std::unique_lock<std::mutex> lk(ls->m_AcceptLock);
        if ((LISTENING != ls->m_Status) || ls->m_pUDT->m_bBroken)
        {
			// This socket has been closed.
			accepted = true;
        }
        else if (ls->m_pQueuedSockets->size() > 0)
        {
			u = *(ls->m_pQueuedSockets->begin());
			ls->m_pAcceptSockets->insert(ls->m_pAcceptSockets->end(), u);
			ls->m_pQueuedSockets->erase(ls->m_pQueuedSockets->begin());
			accepted = true;
        }
        else if (!ls->m_pUDT->m_bSynRecving)
        {
			accepted = true;
        }

		if (!accepted && (LISTENING == ls->m_Status)){
			ls->m_AcceptCond.wait(lk);
		}

		if (ls->m_pQueuedSockets->empty()){
			m_EPoll.update_events(listen, ls->m_pUDT->m_sPollID, UDT_EPOLL_IN, false);
		}

		ls->m_AcceptLock.unlock();
	}

   if (u == CUDT::INVALID_SOCK)
   {
      // non-blocking receiving, no connection available
      if (!ls->m_pUDT->m_bSynRecving)
         throw CUDTException(6, 2, 0);

      // listening socket is closed
      throw CUDTException(5, 6, 0);
   }

   if ((addr != NULL) && (addrlen != NULL))
   {
      if (AF_INET == locate(u)->m_iIPversion)
         *addrlen = sizeof(sockaddr_in);
      else
         *addrlen = sizeof(sockaddr_in6);

      // copy address information of peer node
      memcpy(addr, locate(u)->m_pPeerAddr, *addrlen);
   }

   return u;
}

int CUDTUnited::connect(const UDTSOCKET u, const sockaddr* name, int namelen)
{
   CUDTSocket* s = locate(u);
   if (NULL == s)
      throw CUDTException(5, 4, 0);

   CGuard cg(s->m_ControlLock);

   // check the size of SOCKADDR structure
   if (AF_INET == s->m_iIPversion)
   {
      if (namelen != sizeof(sockaddr_in))
         throw CUDTException(5, 3, 0);
   }
   else
   {
      if (namelen != sizeof(sockaddr_in6))
         throw CUDTException(5, 3, 0);
   }

   // a socket can "connect" only if it is in INIT or OPENED status
   if (INIT == s->m_Status)
   {
      if (!s->m_pUDT->m_bRendezvous)
      {
         s->m_pUDT->open();
         updateMux(s);
         s->m_Status = OPENED;
      }
      else
         throw CUDTException(5, 8, 0);
   }
   else if (OPENED != s->m_Status)
      throw CUDTException(5, 2, 0);

   // connect_complete() may be called before connect() returns.
   // So we need to update the status before connect() is called,
   // otherwise the status may be overwritten with wrong value (CONNECTED vs. CONNECTING).
   s->m_Status = CONNECTING;
   try
   {
      s->m_pUDT->connect(name);
   }
   catch (CUDTException e)
   {
      s->m_Status = OPENED;
      throw e;
   }

   // record peer address
   delete s->m_pPeerAddr;
   if (AF_INET == s->m_iIPversion)
   {
      s->m_pPeerAddr = (sockaddr*)(new sockaddr_in);
      memcpy(s->m_pPeerAddr, name, sizeof(sockaddr_in));
   }
   else
   {
      s->m_pPeerAddr = (sockaddr*)(new sockaddr_in6);
      memcpy(s->m_pPeerAddr, name, sizeof(sockaddr_in6));
   }

   return 0;
}

void CUDTUnited::connect_complete(const UDTSOCKET u)
{
   CUDTSocket* s = locate(u);
   if (NULL == s)
      throw CUDTException(5, 4, 0);

   // copy address information of local node
   // the local port must be correctly assigned BEFORE CUDT::connect(),
   // otherwise if connect() fails, the multiplexer cannot be located by garbage collection and will cause leak
   s->m_pUDT->m_pSndQueue->m_pChannel->getSockAddr(s->m_pSelfAddr);
   CIPAddress::pton(s->m_pSelfAddr, s->m_pUDT->m_piSelfIP, s->m_iIPversion);

   s->m_Status = CONNECTED;
}

int CUDTUnited::close(const UDTSOCKET u)
{
   CUDTSocket* s = locate(u);
   if (NULL == s)
      throw CUDTException(5, 4, 0);

   CGuard socket_cg(s->m_ControlLock);

   if (s->m_Status == LISTENING)
   {
      if (s->m_pUDT->m_bBroken)
         return 0;

      s->m_TimeStamp = CTimer::getTime();
      s->m_pUDT->m_bBroken = true;

      // broadcast all "accept" waiting
	  s->m_AcceptLock.lock();
	  s->m_AcceptCond.notify_all();
	  s->m_AcceptLock.unlock();

      return 0;
   }

   s->m_pUDT->close();

   // synchronize with garbage collection.
   CGuard manager_cg(m_ControlLock);

   // since "s" is located before m_ControlLock, locate it again in case it became invalid
   map<UDTSOCKET, CUDTSocket*>::iterator i = m_Sockets.find(u);
   if ((i == m_Sockets.end()) || (i->second->m_Status == CLOSED))
      return 0;
   s = i->second;

   s->m_Status = CLOSED;

   // a socket will not be immediated removed when it is closed
   // in order to prevent other methods from accessing invalid address
   // a timer is started and the socket will be removed after approximately 1 second
   s->m_TimeStamp = CTimer::getTime();

   m_Sockets.erase(s->m_SocketID);
   m_ClosedSockets.insert(pair<UDTSOCKET, CUDTSocket*>(s->m_SocketID, s));

   CTimer::triggerEvent();

   return 0;
}

int CUDTUnited::getpeername(const UDTSOCKET u, sockaddr* name, int* namelen)
{
   if (CONNECTED != getStatus(u))
      throw CUDTException(2, 2, 0);

   CUDTSocket* s = locate(u);

   if (NULL == s)
      throw CUDTException(5, 4, 0);

   if (!s->m_pUDT->m_bConnected || s->m_pUDT->m_bBroken)
      throw CUDTException(2, 2, 0);

   if (AF_INET == s->m_iIPversion)
      *namelen = sizeof(sockaddr_in);
   else
      *namelen = sizeof(sockaddr_in6);

   // copy address information of peer node
   memcpy(name, s->m_pPeerAddr, *namelen);

   return 0;
}

int CUDTUnited::getsockname(const UDTSOCKET u, sockaddr* name, int* namelen)
{
   CUDTSocket* s = locate(u);

   if (NULL == s)
      throw CUDTException(5, 4, 0);

   if (s->m_pUDT->m_bBroken)
      throw CUDTException(5, 4, 0);

   if (INIT == s->m_Status)
      throw CUDTException(2, 2, 0);

   if (AF_INET == s->m_iIPversion)
      *namelen = sizeof(sockaddr_in);
   else
      *namelen = sizeof(sockaddr_in6);

   // copy address information of local node
   memcpy(name, s->m_pSelfAddr, *namelen);

   return 0;
}

int CUDTUnited::select(ud_set* readfds, ud_set* writefds, ud_set* exceptfds, const timeval* timeout)
{
   uint64_t entertime = CTimer::getTime();

   uint64_t to;
   if (NULL == timeout)
      to = 0xFFFFFFFFFFFFFFFFULL;
   else
      to = timeout->tv_sec * 1000000 + timeout->tv_usec;

   // initialize results
   int count = 0;
   set<UDTSOCKET> rs, ws, es;

   // retrieve related UDT sockets
   vector<CUDTSocket*> ru, wu, eu;
   CUDTSocket* s;
   if (NULL != readfds)
      for (set<UDTSOCKET>::iterator i1 = readfds->begin(); i1 != readfds->end(); ++ i1)
      {
         if (BROKEN == getStatus(*i1))
         {
            rs.insert(*i1);
            ++ count;
         }
         else if (NULL == (s = locate(*i1)))
            throw CUDTException(5, 4, 0);
         else
            ru.push_back(s);
      }
   if (NULL != writefds)
      for (set<UDTSOCKET>::iterator i2 = writefds->begin(); i2 != writefds->end(); ++ i2)
      {
         if (BROKEN == getStatus(*i2))
         {
            ws.insert(*i2);
            ++ count;
         }
         else if (NULL == (s = locate(*i2)))
            throw CUDTException(5, 4, 0);
         else
            wu.push_back(s);
      }
   if (NULL != exceptfds)
      for (set<UDTSOCKET>::iterator i3 = exceptfds->begin(); i3 != exceptfds->end(); ++ i3)
      {
         if (BROKEN == getStatus(*i3))
         {
            es.insert(*i3);
            ++ count;
         }
         else if (NULL == (s = locate(*i3)))
            throw CUDTException(5, 4, 0);
         else
            eu.push_back(s);
      }

   do
   {
      // query read sockets
      for (vector<CUDTSocket*>::iterator j1 = ru.begin(); j1 != ru.end(); ++ j1)
      {
         s = *j1;

         if ((s->m_pUDT->m_bConnected && (s->m_pUDT->m_pRcvBuffer->getRcvDataSize() > 0) && ((s->m_pUDT->m_iSockType == UDT_STREAM) || (s->m_pUDT->m_pRcvBuffer->getRcvMsgNum() > 0)))
            || (!s->m_pUDT->m_bListening && (s->m_pUDT->m_bBroken || !s->m_pUDT->m_bConnected))
            || (s->m_pUDT->m_bListening && (s->m_pQueuedSockets->size() > 0))
            || (s->m_Status == CLOSED))
         {
            rs.insert(s->m_SocketID);
            ++ count;
         }
      }

      // query write sockets
      for (vector<CUDTSocket*>::iterator j2 = wu.begin(); j2 != wu.end(); ++ j2)
      {
         s = *j2;

         if ((s->m_pUDT->m_bConnected && (s->m_pUDT->m_pSndBuffer->getCurrBufSize() < s->m_pUDT->m_iSndBufSize))
            || s->m_pUDT->m_bBroken || !s->m_pUDT->m_bConnected || (s->m_Status == CLOSED))
         {
            ws.insert(s->m_SocketID);
            ++ count;
         }
      }

      // query exceptions on sockets
      for (vector<CUDTSocket*>::iterator j3 = eu.begin(); j3 != eu.end(); ++ j3)
      {
         // check connection request status, not supported now
      }

      if (0 < count)
         break;

      CTimer::waitForEvent();
   } while (to > CTimer::getTime() - entertime);

   if (NULL != readfds)
      *readfds = rs;

   if (NULL != writefds)
      *writefds = ws;

   if (NULL != exceptfds)
      *exceptfds = es;

   return count;
}

int CUDTUnited::selectEx(const vector<UDTSOCKET>& fds, vector<UDTSOCKET>* readfds, vector<UDTSOCKET>* writefds, vector<UDTSOCKET>* exceptfds, int64_t msTimeOut)
{
   uint64_t entertime = CTimer::getTime();

   uint64_t to;
   if (msTimeOut >= 0)
      to = msTimeOut * 1000;
   else
      to = 0xFFFFFFFFFFFFFFFFULL;

   // initialize results
   int count = 0;
   if (NULL != readfds)
      readfds->clear();
   if (NULL != writefds)
      writefds->clear();
   if (NULL != exceptfds)
      exceptfds->clear();

   do
   {
      for (vector<UDTSOCKET>::const_iterator i = fds.begin(); i != fds.end(); ++ i)
      {
         CUDTSocket* s = locate(*i);

         if ((NULL == s) || s->m_pUDT->m_bBroken || (s->m_Status == CLOSED))
         {
            if (NULL != exceptfds)
            {
               exceptfds->push_back(*i);
               ++ count;
            }
            continue;
         }

         if (NULL != readfds)
         {
            if ((s->m_pUDT->m_bConnected && (s->m_pUDT->m_pRcvBuffer->getRcvDataSize() > 0) && ((s->m_pUDT->m_iSockType == UDT_STREAM) || (s->m_pUDT->m_pRcvBuffer->getRcvMsgNum() > 0)))
               || (s->m_pUDT->m_bListening && (s->m_pQueuedSockets->size() > 0)))
            {
               readfds->push_back(s->m_SocketID);
               ++ count;
            }
         }

         if (NULL != writefds)
         {
            if (s->m_pUDT->m_bConnected && (s->m_pUDT->m_pSndBuffer->getCurrBufSize() < s->m_pUDT->m_iSndBufSize))
            {
               writefds->push_back(s->m_SocketID);
               ++ count;
            }
         }
      }

      if (count > 0)
         break;

      CTimer::waitForEvent();
   } while (to > CTimer::getTime() - entertime);

   return count;
}

int CUDTUnited::epoll_create()
{
   return m_EPoll.create();
}

int CUDTUnited::epoll_add_usock(const int eid, const UDTSOCKET u, const int* events)
{
   CUDTSocket* s = locate(u);
   int ret = -1;
   if (NULL != s)
   {
      ret = m_EPoll.add_usock(eid, u, events);
      s->m_pUDT->addEPoll(eid);
   }
   else
   {
      throw CUDTException(5, 4);
   }

   return ret;
}

int CUDTUnited::epoll_add_ssock(const int eid, const SYSSOCKET s, const int* events)
{
   return m_EPoll.add_ssock(eid, s, events);
}

int CUDTUnited::epoll_remove_usock(const int eid, const UDTSOCKET u)
{
   int ret = m_EPoll.remove_usock(eid, u);

   CUDTSocket* s = locate(u);
   if (NULL != s)
   {
      s->m_pUDT->removeEPoll(eid);
   }
   //else
   //{
   //   throw CUDTException(5, 4);
   //}

   return ret;
}

int CUDTUnited::epoll_remove_ssock(const int eid, const SYSSOCKET s)
{
   return m_EPoll.remove_ssock(eid, s);
}

int CUDTUnited::epoll_wait(const int eid, set<UDTSOCKET>* readfds, set<UDTSOCKET>* writefds, int64_t msTimeOut, set<SYSSOCKET>* lrfds, set<SYSSOCKET>* lwfds)
{
   return m_EPoll.wait(eid, readfds, writefds, msTimeOut, lrfds, lwfds);
}

int CUDTUnited::epoll_release(const int eid)
{
   return m_EPoll.release(eid);
}

CUDTSocket* CUDTUnited::locate(const UDTSOCKET u)
{
   CGuard cg(m_ControlLock);

   map<UDTSOCKET, CUDTSocket*>::iterator i = m_Sockets.find(u);

   if ((i == m_Sockets.end()) || (i->second->m_Status == CLOSED))
      return NULL;

   return i->second;
}

CUDTSocket* CUDTUnited::locate(const sockaddr* peer, const UDTSOCKET id, int32_t isn)
{
   CGuard cg(m_ControlLock);

   map<int64_t, set<UDTSOCKET> >::iterator i = m_PeerRec.find((id << 30) + isn);
   if (i == m_PeerRec.end())
      return NULL;

   for (set<UDTSOCKET>::iterator j = i->second.begin(); j != i->second.end(); ++ j)
   {
      map<UDTSOCKET, CUDTSocket*>::iterator k = m_Sockets.find(*j);
      // this socket might have been closed and moved m_ClosedSockets
      if (k == m_Sockets.end())
         continue;

      if (CIPAddress::ipcmp(peer, k->second->m_pPeerAddr, k->second->m_iIPversion))
         return k->second;
   }

   return NULL;
}

void CUDTUnited::checkBrokenSockets()
{
   CGuard cg(m_ControlLock);

   // set of sockets To Be Closed and To Be Removed
   vector<UDTSOCKET> tbc;
   vector<UDTSOCKET> tbr;

   for (map<UDTSOCKET, CUDTSocket*>::iterator i = m_Sockets.begin(); i != m_Sockets.end(); ++ i)
   {
      // check broken connection
      if (i->second->m_pUDT->m_bBroken)
      {
         if (i->second->m_Status == LISTENING)
         {
            // for a listening socket, it should wait an extra 3 seconds in case a client is connecting
            if (CTimer::getTime() - i->second->m_TimeStamp < 3000000)
               continue;
         }
         else if ((i->second->m_pUDT->m_pRcvBuffer != NULL) && (i->second->m_pUDT->m_pRcvBuffer->getRcvDataSize() > 0) && (i->second->m_pUDT->m_iBrokenCounter -- > 0))
         {
            // if there is still data in the receiver buffer, wait longer
            continue;
         }

         //close broken connections and start removal timer
         i->second->m_Status = CLOSED;
         i->second->m_TimeStamp = CTimer::getTime();
         tbc.push_back(i->first);
         m_ClosedSockets[i->first] = i->second;

         // remove from listener's queue
         map<UDTSOCKET, CUDTSocket*>::iterator ls = m_Sockets.find(i->second->m_ListenSocket);
         if (ls == m_Sockets.end())
         {
            ls = m_ClosedSockets.find(i->second->m_ListenSocket);
            if (ls == m_ClosedSockets.end())
               continue;
         }

         CGuard::enterCS(ls->second->m_AcceptLock);
         ls->second->m_pQueuedSockets->erase(i->second->m_SocketID);
         ls->second->m_pAcceptSockets->erase(i->second->m_SocketID);
         CGuard::leaveCS(ls->second->m_AcceptLock);
      }
   }

   for (map<UDTSOCKET, CUDTSocket*>::iterator j = m_ClosedSockets.begin(); j != m_ClosedSockets.end(); ++ j)
   {
      if (j->second->m_pUDT->m_ullLingerExpiration > 0)
      {
         // asynchronous close: 
         if ((NULL == j->second->m_pUDT->m_pSndBuffer) || (0 == j->second->m_pUDT->m_pSndBuffer->getCurrBufSize()) || (j->second->m_pUDT->m_ullLingerExpiration <= CTimer::getTime()))
         {
            j->second->m_pUDT->m_ullLingerExpiration = 0;
            j->second->m_pUDT->m_bClosing = true;
            j->second->m_TimeStamp = CTimer::getTime();
         }
      }

      // timeout 1 second to destroy a socket AND it has been removed from RcvUList
      if ((CTimer::getTime() - j->second->m_TimeStamp > 1000000) && ((NULL == j->second->m_pUDT->m_pRNode) || !j->second->m_pUDT->m_pRNode->m_bOnList))
      {
         tbr.push_back(j->first);
      }
   }

   // move closed sockets to the ClosedSockets structure
   for (vector<UDTSOCKET>::iterator k = tbc.begin(); k != tbc.end(); ++ k)
      m_Sockets.erase(*k);

   // remove those timeout sockets
   for (vector<UDTSOCKET>::iterator l = tbr.begin(); l != tbr.end(); ++ l)
      removeSocket(*l);
}

void CUDTUnited::removeSocket(const UDTSOCKET u)
{
   map<UDTSOCKET, CUDTSocket*>::iterator i = m_ClosedSockets.find(u);

   // invalid socket ID
   if (i == m_ClosedSockets.end())
      return;

   // decrease multiplexer reference count, and remove it if necessary
   const int mid = i->second->m_iMuxID;

   if (NULL != i->second->m_pQueuedSockets)
   {
      CGuard::enterCS(i->second->m_AcceptLock);

      // if it is a listener, close all un-accepted sockets in its queue and remove them later
      for (set<UDTSOCKET>::iterator q = i->second->m_pQueuedSockets->begin(); q != i->second->m_pQueuedSockets->end(); ++ q)
      {
         m_Sockets[*q]->m_pUDT->m_bBroken = true;
         m_Sockets[*q]->m_pUDT->close();
         m_Sockets[*q]->m_TimeStamp = CTimer::getTime();
         m_Sockets[*q]->m_Status = CLOSED;
         m_ClosedSockets[*q] = m_Sockets[*q];
         m_Sockets.erase(*q);
      }

      CGuard::leaveCS(i->second->m_AcceptLock);
   }

   // remove from peer rec
   map<int64_t, set<UDTSOCKET> >::iterator j = m_PeerRec.find((i->second->m_PeerID << 30) + i->second->m_iISN);
   if (j != m_PeerRec.end())
   {
      j->second.erase(u);
      if (j->second.empty())
         m_PeerRec.erase(j);
   }

   // delete this one
   i->second->m_pUDT->close();
   delete i->second;
   m_ClosedSockets.erase(i);

   map<int, CMultiplexer>::iterator m;
   m = m_mMultiplexer.find(mid);
   if (m == m_mMultiplexer.end())
   {
      //something is wrong!!!
      return;
   }

   m->second.m_iRefCount --;
   if (0 == m->second.m_iRefCount)
   {
      m->second.m_pChannel->close();
      delete m->second.m_pSndQueue;
      delete m->second.m_pRcvQueue;
      delete m->second.m_pTimer;
      delete m->second.m_pChannel;
      m_mMultiplexer.erase(m);
   }
}

void CUDTUnited::setError(CUDTException* e)
{
   #ifndef WIN32
      delete (CUDTException*)pthread_getspecific(m_TLSError);
      pthread_setspecific(m_TLSError, e);
   #else
      CGuard tg(m_TLSLock);
      delete (CUDTException*)TlsGetValue(m_TLSError);
      TlsSetValue(m_TLSError, e);
      m_mTLSRecord[GetCurrentThreadId()] = e;
   #endif
}

CUDTException* CUDTUnited::getError()
{
   #ifndef WIN32
      if(NULL == pthread_getspecific(m_TLSError))
         pthread_setspecific(m_TLSError, new CUDTException);
      return (CUDTException*)pthread_getspecific(m_TLSError);
   #else
      CGuard tg(m_TLSLock);
      if(NULL == TlsGetValue(m_TLSError))
      {
         CUDTException* e = new CUDTException;
         TlsSetValue(m_TLSError, e);
         m_mTLSRecord[GetCurrentThreadId()] = e;
      }
      return (CUDTException*)TlsGetValue(m_TLSError);
   #endif
}

#ifdef WIN32
void CUDTUnited::checkTLSValue()
{
   CGuard tg(m_TLSLock);

   vector<DWORD> tbr;
   for (map<DWORD, CUDTException*>::iterator i = m_mTLSRecord.begin(); i != m_mTLSRecord.end(); ++ i)
   {
      HANDLE h = OpenThread(THREAD_QUERY_INFORMATION, FALSE, i->first);
      if (NULL == h)
      {
         tbr.push_back(i->first);
         break;
      }
      if (WAIT_OBJECT_0 == WaitForSingleObject(h, 0))
      {
         delete i->second;
         tbr.push_back(i->first);
      }
      CloseHandle(h);
   }
   for (vector<DWORD>::iterator j = tbr.begin(); j != tbr.end(); ++ j)
      m_mTLSRecord.erase(*j);
}
#endif

void CUDTUnited::updateMux(CUDTSocket* s, const sockaddr* addr, const UDPSOCKET* udpsock)
{
   CGuard cg(m_ControlLock);

   if ((s->m_pUDT->m_bReuseAddr) && (NULL != addr))
   {
      int port = (AF_INET == s->m_pUDT->m_iIPversion) ? ntohs(((sockaddr_in*)addr)->sin_port) : ntohs(((sockaddr_in6*)addr)->sin6_port);

      // find a reusable address
      for (map<int, CMultiplexer>::iterator i = m_mMultiplexer.begin(); i != m_mMultiplexer.end(); ++ i)
      {
         if ((i->second.m_iIPversion == s->m_pUDT->m_iIPversion) && (i->second.m_iMSS == s->m_pUDT->m_iMSS) && i->second.m_bReusable)
         {
            if (i->second.m_iPort == port)
            {
               // reuse the existing multiplexer
               ++ i->second.m_iRefCount;
               s->m_pUDT->m_pSndQueue = i->second.m_pSndQueue;
               s->m_pUDT->m_pRcvQueue = i->second.m_pRcvQueue;
               s->m_iMuxID = i->second.m_iID;
               return;
            }
         }
      }
   }

   // a new multiplexer is needed
   CMultiplexer m;
   m.m_iMSS = s->m_pUDT->m_iMSS;
   m.m_iIPversion = s->m_pUDT->m_iIPversion;
   m.m_iRefCount = 1;
   m.m_bReusable = s->m_pUDT->m_bReuseAddr;
   m.m_iID = s->m_SocketID;

   m.m_pChannel = new CChannel(s->m_pUDT->m_iIPversion);
   m.m_pChannel->setSndBufSize(s->m_pUDT->m_iUDPSndBufSize);
   m.m_pChannel->setRcvBufSize(s->m_pUDT->m_iUDPRcvBufSize);

   try
   {
      if (NULL != udpsock)
         m.m_pChannel->open(*udpsock);
      else
         m.m_pChannel->open(addr);
   }
   catch (CUDTException& e)
   {
      m.m_pChannel->close();
      delete m.m_pChannel;
      throw e;
   }

   sockaddr* sa = (AF_INET == s->m_pUDT->m_iIPversion) ? (sockaddr*) new sockaddr_in : (sockaddr*) new sockaddr_in6;
   m.m_pChannel->getSockAddr(sa);
   m.m_iPort = (AF_INET == s->m_pUDT->m_iIPversion) ? ntohs(((sockaddr_in*)sa)->sin_port) : ntohs(((sockaddr_in6*)sa)->sin6_port);
   if (AF_INET == s->m_pUDT->m_iIPversion) delete (sockaddr_in*)sa; else delete (sockaddr_in6*)sa;

   m.m_pTimer = new CTimer;

   m.m_pSndQueue = new CSndQueue;
   m.m_pSndQueue->init(m.m_pChannel, m.m_pTimer);
   m.m_pRcvQueue = new CRcvQueue;
   m.m_pRcvQueue->init(32, s->m_pUDT->m_iPayloadSize, m.m_iIPversion, 1024, m.m_pChannel, m.m_pTimer);

   m_mMultiplexer[m.m_iID] = m;

   s->m_pUDT->m_pSndQueue = m.m_pSndQueue;
   s->m_pUDT->m_pRcvQueue = m.m_pRcvQueue;
   s->m_iMuxID = m.m_iID;
}

void CUDTUnited::updateMux(CUDTSocket* s, const CUDTSocket* ls)
{
   CGuard cg(m_ControlLock);

   int port = (AF_INET == ls->m_iIPversion) ? ntohs(((sockaddr_in*)ls->m_pSelfAddr)->sin_port) : ntohs(((sockaddr_in6*)ls->m_pSelfAddr)->sin6_port);

   // find the listener's address
   for (map<int, CMultiplexer>::iterator i = m_mMultiplexer.begin(); i != m_mMultiplexer.end(); ++ i)
   {
      if (i->second.m_iPort == port)
      {
         // reuse the existing multiplexer
         ++ i->second.m_iRefCount;
         s->m_pUDT->m_pSndQueue = i->second.m_pSndQueue;
         s->m_pUDT->m_pRcvQueue = i->second.m_pRcvQueue;
         s->m_iMuxID = i->second.m_iID;
         return;
      }
   }
}

#ifndef WIN32
   void* CUDTUnited::garbageCollect(void* p)
#else
   DWORD WINAPI CUDTUnited::garbageCollect(LPVOID p)
#endif
{
   CUDTUnited* self = (CUDTUnited*)p;

   std::unique_lock<std::mutex> lk(self->m_GCStopLock);

   while (!self->m_bClosing)
   {
      self->checkBrokenSockets();

      #ifdef WIN32
         self->checkTLSValue();
      #endif


	  self->m_GCStopCond.wait_for(lk, std::chrono::milliseconds(1000));
   }

   // remove all sockets and multiplexers
   CGuard::enterCS(self->m_ControlLock);
   for (map<UDTSOCKET, CUDTSocket*>::iterator i = self->m_Sockets.begin(); i != self->m_Sockets.end(); ++ i)
   {
      i->second->m_pUDT->m_bBroken = true;
      i->second->m_pUDT->close();
      i->second->m_Status = CLOSED;
      i->second->m_TimeStamp = CTimer::getTime();
      self->m_ClosedSockets[i->first] = i->second;

      // remove from listener's queue
      map<UDTSOCKET, CUDTSocket*>::iterator ls = self->m_Sockets.find(i->second->m_ListenSocket);
      if (ls == self->m_Sockets.end())
      {
         ls = self->m_ClosedSockets.find(i->second->m_ListenSocket);
         if (ls == self->m_ClosedSockets.end())
            continue;
      }

      CGuard::enterCS(ls->second->m_AcceptLock);
      ls->second->m_pQueuedSockets->erase(i->second->m_SocketID);
      ls->second->m_pAcceptSockets->erase(i->second->m_SocketID);
      CGuard::leaveCS(ls->second->m_AcceptLock);
   }
   self->m_Sockets.clear();

   for (map<UDTSOCKET, CUDTSocket*>::iterator j = self->m_ClosedSockets.begin(); j != self->m_ClosedSockets.end(); ++ j)
   {
      j->second->m_TimeStamp = 0;
   }
   CGuard::leaveCS(self->m_ControlLock);

   while (true)
   {
      self->checkBrokenSockets();

      CGuard::enterCS(self->m_ControlLock);
      bool empty = self->m_ClosedSockets.empty();
      CGuard::leaveCS(self->m_ControlLock);

      if (empty)
         break;

      CTimer::sleep();
   }

   #ifndef WIN32
      return NULL;
   #else
      return 0;
   #endif
}

////////////////////////////////////////////////////////////////////////////////

int CUDT::startup()
{
   return s_UDTUnited.startup();
}

int CUDT::cleanup()
{
   return s_UDTUnited.cleanup();
}

UDTSOCKET CUDT::socket(int af, int type, int)
{
   if (!s_UDTUnited.m_bGCStatus)
      s_UDTUnited.startup();

   try
   {
      return s_UDTUnited.newSocket(af, type);
   }
   catch (CUDTException& e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return INVALID_SOCK;
   }
   catch (bad_alloc&)
   {
      s_UDTUnited.setError(new CUDTException(3, 2, 0));
      return INVALID_SOCK;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return INVALID_SOCK;
   }
}

int CUDT::bind(UDTSOCKET u, const sockaddr* name, int namelen)
{
   try
   {
      return s_UDTUnited.bind(u, name, namelen);
   }
   catch (CUDTException& e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (bad_alloc&)
   {
      s_UDTUnited.setError(new CUDTException(3, 2, 0));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::bind(UDTSOCKET u, UDPSOCKET udpsock)
{
   try
   {
      return s_UDTUnited.bind(u, udpsock);
   }
   catch (CUDTException& e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (bad_alloc&)
   {
      s_UDTUnited.setError(new CUDTException(3, 2, 0));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::listen(UDTSOCKET u, int backlog)
{
   try
   {
      return s_UDTUnited.listen(u, backlog);
   }
   catch (CUDTException& e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (bad_alloc&)
   {
      s_UDTUnited.setError(new CUDTException(3, 2, 0));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

UDTSOCKET CUDT::accept(UDTSOCKET u, sockaddr* addr, int* addrlen)
{
   try
   {
      return s_UDTUnited.accept(u, addr, addrlen);
   }
   catch (CUDTException& e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return INVALID_SOCK;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return INVALID_SOCK;
   }
}

int CUDT::connect(UDTSOCKET u, const sockaddr* name, int namelen)
{
   try
   {
      return s_UDTUnited.connect(u, name, namelen);
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (bad_alloc&)
   {
      s_UDTUnited.setError(new CUDTException(3, 2, 0));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::close(UDTSOCKET u)
{
   try
   {
      return s_UDTUnited.close(u);
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::getpeername(UDTSOCKET u, sockaddr* name, int* namelen)
{
   try
   {
      return s_UDTUnited.getpeername(u, name, namelen);
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::getsockname(UDTSOCKET u, sockaddr* name, int* namelen)
{
   try
   {
      return s_UDTUnited.getsockname(u, name, namelen);;
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::getsockopt(UDTSOCKET u, int, UDTOpt optname, void* optval, int* optlen)
{
   try
   {
      CUDT* udt = s_UDTUnited.lookup(u);
      udt->getOpt(optname, optval, *optlen);
      return 0;
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::setsockopt(UDTSOCKET u, int, UDTOpt optname, const void* optval, int optlen)
{
   try
   {
      CUDT* udt = s_UDTUnited.lookup(u);
      udt->setOpt(optname, optval, optlen);
      return 0;
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::send(UDTSOCKET u, const char* buf, int len, int)
{
   try
   {
      CUDT* udt = s_UDTUnited.lookup(u);
      return udt->send(buf, len);
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (bad_alloc&)
   {
      s_UDTUnited.setError(new CUDTException(3, 2, 0));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::recv(UDTSOCKET u, char* buf, int len, int)
{
   try
   {
      CUDT* udt = s_UDTUnited.lookup(u);
	  return udt->recv(buf, len);;
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::sendmsg(UDTSOCKET u, const char* buf, int len, int ttl, bool inorder)
{
   try
   {
      CUDT* udt = s_UDTUnited.lookup(u);
      return udt->sendmsg(buf, len, ttl, inorder);
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (bad_alloc&)
   {
      s_UDTUnited.setError(new CUDTException(3, 2, 0));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::recvmsg(UDTSOCKET u, char* buf, int len)
{
   try
   {
      CUDT* udt = s_UDTUnited.lookup(u);
      return udt->recvmsg(buf, len);
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int64_t CUDT::sendfile(UDTSOCKET u, fstream& ifs, int64_t& offset, int64_t size, int block)
{
   try
   {
      CUDT* udt = s_UDTUnited.lookup(u);
      return udt->sendfile(ifs, offset, size, block);
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (bad_alloc&)
   {
      s_UDTUnited.setError(new CUDTException(3, 2, 0));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int64_t CUDT::recvfile(UDTSOCKET u, fstream& ofs, int64_t& offset, int64_t size, int block)
{
   try
   {
      CUDT* udt = s_UDTUnited.lookup(u);
      return udt->recvfile(ofs, offset, size, block);
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::select(int, ud_set* readfds, ud_set* writefds, ud_set* exceptfds, const timeval* timeout)
{
   if ((NULL == readfds) && (NULL == writefds) && (NULL == exceptfds))
   {
      s_UDTUnited.setError(new CUDTException(5, 3, 0));
      return ERROR;
   }

   try
   {
      return s_UDTUnited.select(readfds, writefds, exceptfds, timeout);
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (bad_alloc&)
   {
      s_UDTUnited.setError(new CUDTException(3, 2, 0));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::selectEx(const vector<UDTSOCKET>& fds, vector<UDTSOCKET>* readfds, vector<UDTSOCKET>* writefds, vector<UDTSOCKET>* exceptfds, int64_t msTimeOut)
{
   if ((NULL == readfds) && (NULL == writefds) && (NULL == exceptfds))
   {
      s_UDTUnited.setError(new CUDTException(5, 3, 0));
      return ERROR;
   }

   try
   {
      return s_UDTUnited.selectEx(fds, readfds, writefds, exceptfds, msTimeOut);
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (bad_alloc&)
   {
      s_UDTUnited.setError(new CUDTException(3, 2, 0));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::epoll_create()
{
   try
   {
      return s_UDTUnited.epoll_create();
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::epoll_add_usock(const int eid, const UDTSOCKET u, const int* events)
{
   try
   {
      return s_UDTUnited.epoll_add_usock(eid, u, events);
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::epoll_add_ssock(const int eid, const SYSSOCKET s, const int* events)
{
   try
   {
      return s_UDTUnited.epoll_add_ssock(eid, s, events);
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::epoll_remove_usock(const int eid, const UDTSOCKET u)
{
   try
   {
      return s_UDTUnited.epoll_remove_usock(eid, u);
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::epoll_remove_ssock(const int eid, const SYSSOCKET s)
{
   try
   {
      return s_UDTUnited.epoll_remove_ssock(eid, s);
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::epoll_wait(const int eid, set<UDTSOCKET>* readfds, set<UDTSOCKET>* writefds, int64_t msTimeOut, set<SYSSOCKET>* lrfds, set<SYSSOCKET>* lwfds)
{
   try
   {
      return s_UDTUnited.epoll_wait(eid, readfds, writefds, msTimeOut, lrfds, lwfds);
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

int CUDT::epoll_release(const int eid)
{
   try
   {
      return s_UDTUnited.epoll_release(eid);
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

CUDTException& CUDT::getlasterror()
{
   return *s_UDTUnited.getError();
}

int CUDT::perfmon(UDTSOCKET u, CPerfMon* perf, bool clear)
{
   try
   {
      CUDT* udt = s_UDTUnited.lookup(u);
      udt->sample(perf, clear);
      return 0;
   }
   catch (CUDTException e)
   {
      s_UDTUnited.setError(new CUDTException(e));
      return ERROR;
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return ERROR;
   }
}

CUDT* CUDT::getUDTHandle(UDTSOCKET u)
{
   try
   {
      return s_UDTUnited.lookup(u);
   }
   catch (...)
   {
      return NULL;
   }
}

UDTSTATUS CUDT::getsockstate(UDTSOCKET u)
{
   try
   {
      return s_UDTUnited.getStatus(u);
   }
   catch (...)
   {
      s_UDTUnited.setError(new CUDTException(-1, 0, 0));
      return NONEXIST;
   }
}


////////////////////////////////////////////////////////////////////////////////

namespace UDT
{

int startup()
{
   return CUDT::startup();
}

int cleanup()
{
   return CUDT::cleanup();
}

UDTSOCKET socket(int af, int type, int protocol)
{
   return CUDT::socket(af, type, protocol);
}

int bind(UDTSOCKET u, const struct sockaddr* name, int namelen)
{
   return CUDT::bind(u, name, namelen);
}

int bind2(UDTSOCKET u, UDPSOCKET udpsock)
{
   return CUDT::bind(u, udpsock);
}

int listen(UDTSOCKET u, int backlog)
{
   return CUDT::listen(u, backlog);
}

UDTSOCKET accept(UDTSOCKET u, struct sockaddr* addr, int* addrlen)
{
   return CUDT::accept(u, addr, addrlen);
}

int connect(UDTSOCKET u, const struct sockaddr* name, int namelen)
{
   return CUDT::connect(u, name, namelen);
}

int close(UDTSOCKET u)
{
   return CUDT::close(u);
}

int getpeername(UDTSOCKET u, struct sockaddr* name, int* namelen)
{
   return CUDT::getpeername(u, name, namelen);
}

int getsockname(UDTSOCKET u, struct sockaddr* name, int* namelen)
{
   return CUDT::getsockname(u, name, namelen);
}

int getsockopt(UDTSOCKET u, int level, SOCKOPT optname, void* optval, int* optlen)
{
   return CUDT::getsockopt(u, level, optname, optval, optlen);
}

int setsockopt(UDTSOCKET u, int level, SOCKOPT optname, const void* optval, int optlen)
{
   return CUDT::setsockopt(u, level, optname, optval, optlen);
}

int send(UDTSOCKET u, const char* buf, int len, int flags)
{
   return CUDT::send(u, buf, len, flags);
}

int recv(UDTSOCKET u, char* buf, int len, int flags)
{
   return CUDT::recv(u, buf, len, flags);
}

int sendmsg(UDTSOCKET u, const char* buf, int len, int ttl, bool inorder)
{
   return CUDT::sendmsg(u, buf, len, ttl, inorder);
}

int recvmsg(UDTSOCKET u, char* buf, int len)
{
   return CUDT::recvmsg(u, buf, len);
}

int64_t sendfile(UDTSOCKET u, fstream& ifs, int64_t& offset, int64_t size, int block)
{
   return CUDT::sendfile(u, ifs, offset, size, block);
}

int64_t recvfile(UDTSOCKET u, fstream& ofs, int64_t& offset, int64_t size, int block)
{
   return CUDT::recvfile(u, ofs, offset, size, block);
}

int64_t sendfile2(UDTSOCKET u, const char* path, int64_t* offset, int64_t size, int block)
{
   fstream ifs(path, ios::binary | ios::in);
   int64_t ret = CUDT::sendfile(u, ifs, *offset, size, block);
   ifs.close();
   return ret;
}

int64_t recvfile2(UDTSOCKET u, const char* path, int64_t* offset, int64_t size, int block)
{
   fstream ofs(path, ios::binary | ios::out);
   int64_t ret = CUDT::recvfile(u, ofs, *offset, size, block);
   ofs.close();
   return ret;
}

int select(int nfds, UDSET* readfds, UDSET* writefds, UDSET* exceptfds, const struct timeval* timeout)
{
   return CUDT::select(nfds, readfds, writefds, exceptfds, timeout);
}

int selectEx(const vector<UDTSOCKET>& fds, vector<UDTSOCKET>* readfds, vector<UDTSOCKET>* writefds, vector<UDTSOCKET>* exceptfds, int64_t msTimeOut)
{
   return CUDT::selectEx(fds, readfds, writefds, exceptfds, msTimeOut);
}

int epoll_create()
{
   return CUDT::epoll_create();
}

int epoll_add_usock(int eid, UDTSOCKET u, const int* events)
{
   return CUDT::epoll_add_usock(eid, u, events);
}

int epoll_add_ssock(int eid, SYSSOCKET s, const int* events)
{
   return CUDT::epoll_add_ssock(eid, s, events);
}

int epoll_remove_usock(int eid, UDTSOCKET u)
{
   return CUDT::epoll_remove_usock(eid, u);
}

int epoll_remove_ssock(int eid, SYSSOCKET s)
{
   return CUDT::epoll_remove_ssock(eid, s);
}

int epoll_wait(int eid, set<UDTSOCKET>* readfds, set<UDTSOCKET>* writefds, int64_t msTimeOut, set<SYSSOCKET>* lrfds, set<SYSSOCKET>* lwfds)
{
   return CUDT::epoll_wait(eid, readfds, writefds, msTimeOut, lrfds, lwfds);
}

#define SET_RESULT(val, num, fds, it) \
   if ((val != NULL) && !val->empty()) \
   { \
      if (*num > static_cast<int>(val->size())) \
         *num = val->size(); \
      int count = 0; \
      for (it = val->begin(); it != val->end(); ++ it) \
      { \
         if (count >= *num) \
            break; \
         fds[count ++] = *it; \
      } \
   }
int epoll_wait2(int eid, UDTSOCKET* readfds, int* rnum, UDTSOCKET* writefds, int* wnum, int64_t msTimeOut,
                SYSSOCKET* lrfds, int* lrnum, SYSSOCKET* lwfds, int* lwnum)
{
   // This API is an alternative format for epoll_wait, created for compatability with other languages.
   // Users need to pass in an array for holding the returned sockets, with the maximum array length
   // stored in *rnum, etc., which will be updated with returned number of sockets.

   set<UDTSOCKET> readset;
   set<UDTSOCKET> writeset;
   set<SYSSOCKET> lrset;
   set<SYSSOCKET> lwset;
   set<UDTSOCKET>* rval = NULL;
   set<UDTSOCKET>* wval = NULL;
   set<SYSSOCKET>* lrval = NULL;
   set<SYSSOCKET>* lwval = NULL;
   if ((readfds != NULL) && (rnum != NULL))
      rval = &readset;
   if ((writefds != NULL) && (wnum != NULL))
      wval = &writeset;
   if ((lrfds != NULL) && (lrnum != NULL))
      lrval = &lrset;
   if ((lwfds != NULL) && (lwnum != NULL))
      lwval = &lwset;

   int ret = CUDT::epoll_wait(eid, rval, wval, msTimeOut, lrval, lwval);
   if (ret > 0)
   {
      set<UDTSOCKET>::const_iterator i;
      SET_RESULT(rval, rnum, readfds, i);
      SET_RESULT(wval, wnum, writefds, i);
      set<SYSSOCKET>::const_iterator j;
      SET_RESULT(lrval, lrnum, lrfds, j);
      SET_RESULT(lwval, lwnum, lwfds, j);
   }
   return ret;
}

int epoll_release(int eid)
{
   return CUDT::epoll_release(eid);
}

ERRORINFO& getlasterror()
{
   return CUDT::getlasterror();
}

int getlasterror_code()
{
   return CUDT::getlasterror().getErrorCode();
}

const char* getlasterror_desc()
{
   return CUDT::getlasterror().getErrorMessage();
}

int perfmon(UDTSOCKET u, TRACEINFO* perf, bool clear)
{
   return CUDT::perfmon(u, perf, clear);
}

UDTSTATUS getsockstate(UDTSOCKET u)
{
   return CUDT::getsockstate(u);
}

}  // namespace UDT