TCP实现P2P通信、TCP穿越NAT的方法、TCP打洞
当有新的客户端连接到服务器时，服务器负责将该客户端的信息（IP地址、端口号）发送给其他客户端。
//
// 执行者：客户端A
// 有新客户端B登录了，我（客户端A）连接服务器端口 SRV_TCP_HOLE_PORT ，申请与客户端B建立直接的TCP连接
//
BOOL Handle_NewUserLogin ( CSocket &MainSock, t_NewUserLoginPkt *pNewUserLoginPkt )
{
printf ( "New user ( %s:%u:%u ) login server\n", pNewUserLoginPkt->szClientIP,
pNewUserLoginPkt->nClientPort, pNewUserLoginPkt->dwID );
BOOL bRet = FALSE;
DWORD dwThreadID = 0;
t_ReqConnClientPkt ReqConnClientPkt;
CSocket Sock;
CString csSocketAddress;
char szRecvBuffer[NET_BUFFER_SIZE] = {0};
int nRecvBytes = 0;
// 创建打洞Socket，连接服务器协助打洞的端口号 SRV_TCP_HOLE_PORT
try
{
if ( !Sock.Socket () )
{
printf ( "Create socket failed : %s\n", hwFormatMessage(GetLastError()) );
goto finished;
}
UINT nOptValue = 1;
if ( !Sock.SetSockOpt ( SO_REUSEADDR, &nOptValue , sizeof(UINT) ) )
{
printf ( "SetSockOpt socket failed : %s\n", hwFormatMessage(GetLastError()) );
goto finished;
}
if ( !Sock.Bind ( 0 ) )
{
printf ( "Bind socket failed : %s\n", hwFormatMessage(GetLastError()) );
goto finished;
}
if ( !Sock.Connect ( g_pServerAddess, SRV_TCP_HOLE_PORT ) )
{
printf ( "Connect to [%s:%d] failed : %s\n", g_pServerAddess,
SRV_TCP_HOLE_PORT, hwFormatMessage(GetLastError()) );
goto finished;
}
}
catch ( CException e )
{
char szError[255] = {0};
e.GetErrorMessage( szError, sizeof(szError) );
printf ( "Exception occur, %s\n", szError );
goto finished;
}
g_pSock_MakeHole = &Sock;
ASSERT ( g_nHolePort == 0 );
VERIFY ( Sock.GetSockName ( csSocketAddress, g_nHolePort ) );
// 创建一个线程来侦听端口 g_nHolePort 的连接请求
dwThreadID = 0;
g_hThread_Listen = ::CreateThread ( NULL, 0, ::ThreadProc_Listen, LPVOID(NULL), 0, &dwThreadID );
if (!HANDLE_IS_VALID(g_hThread_Listen) ) return FALSE;
Sleep ( 3000 );
// 我（客户端A）向服务器协助打洞的端口号 SRV_TCP_HOLE_PORT 发送申请，希望与新登录的客户端B建立连接
// 服务器会将我的打洞用的外部IP和端口号告诉客户端B
ASSERT ( g_WelcomePkt.dwID > 0 );
ReqConnClientPkt.dwInviterID = g_WelcomePkt.dwID;
ReqConnClientPkt.dwInvitedID = pNewUserLoginPkt->dwID;
if ( Sock.Send ( &ReqConnClientPkt, sizeof(t_ReqConnClientPkt) ) != sizeof(t_ReqConnClientPkt) )
goto finished;
// 等待服务器回应，将客户端B的外部IP地址和端口号告诉我（客户端A）
nRecvBytes = Sock.Receive ( szRecvBuffer, sizeof(szRecvBuffer) );
if ( nRecvBytes > 0 )
{
ASSERT ( nRecvBytes == sizeof(t_SrvReqDirectConnectPkt) );
PACKET_TYPE *pePacketType = (PACKET_TYPE*)szRecvBuffer;
ASSERT ( pePacketType && *pePacketType == PACKET_TYPE_TCP_DIRECT_CONNECT );
Sleep ( 1000 );
Handle_SrvReqDirectConnect ( (t_SrvReqDirectConnectPkt*)szRecvBuffer );
printf ( "Handle_SrvReqDirectConnect end\n" );
}
// 对方断开连接了
else
{
goto finished;
}
bRet = TRUE;
finished:
g_pSock_MakeHole = NULL;
return bRet;
}
