UDP to UDP 数据转发

目的
希望读者在阅读本文之前，已经读过了《『黑客编程』一、TCP to TCP 数据转发》，UDP to UDP可以用作QQ通过转发代理聊天的功能。
应用机器A，提供UDP端口的服务，转发代理机器B，提供UDP转发端口服务，客户机C通过UDP把数据发送到B,B再转发给A，并把A发送的数据转发
给C。

设计
//主程序
Main()
{
beginthread(u2uMainThread());
}

//主线程
u2uMainThread(Param)
{
while(true)
{
创建"本地接收数据SOCK"，用来接收并转发客户端C发送过来的数据
while(read>0)
{
等待并接收客户端C数据
等到后，查找"目标SOCK"
if(没有找到)
{
创建一个新的"目标SOCK"
"目标SOCK"创建成功后，创建"Wait Thread"，
}
用"目标SOCK"发送数据到应用A
}
}
}
//Wait 线程
Wait Thread(Param)
{
创建"目标SOCK"->"连接SOCK"数据转发Thread
等待这个线程结束
释放SOCK资源
}
//TCP2TCP数据转发线程
UDP2UDP Thread(Param)
{
SOCK FROM,TO
while(read >0)
{
readfrom(From,Buff);
Sendto(To,Buff);
}
}

参考代码
参数结构
struct AGENTTCPUDPGATEWAYINFO
{
char TargetIP[40];
int TargetPort;
int LocalPort;
int LocalTmpPort;
};

//主线程
DWORD WINAPI u2umainthread(LPVOID lpvoid)
{
//获取参数
AGENTTCPUDPGATEWAYINFO *pasi = (AGENTTCPUDPGATEWAYINFO*)lpvoid;
AGENTTCPUDPGATEWAYINFO asi;
memcpy(&asi,pasi,sizeof(AGENTTCPUDPGATEWAYINFO));
delete pasi; pasi = NULL;
//-b

int iRet;
struct sockaddr_in UDPLocal,Target;
SOCKET s[2];//s[0]=>UDP socket s[1]=>TCP socket
HANDLE hThread[2]={NULL,NULL};

printf("/nOK!Work mode is udp2udp.");

//监听本地UDP port的地址结构
UDPLocal.sin_family=AF_INET;
UDPLocal.sin_addr.s_addr=INADDR_ANY;
UDPLocal.sin_port=htons(asi.LocalPort);
//目标地址结构
Target.sin_family=AF_INET;
Target.sin_addr.s_addr=inet_addr(asi.TargetIP);
Target.sin_port=htons(asi.TargetPort);
//开始循环
while(1)
{
printf("/n/n************Udp2Udp Start new**************/n/n");
_DelSock(s[0]);
//创建一个UDP socket
s[0]=socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
if(s[0]==INVALID_SOCKET)
{
ShowError("/nUdp2Udp:Create UDP socket");
Sleep(5000);
continue;
}
_AddSock(s[0]);
//bind UDP socket
iRet=bind(s[0],(struct sockaddr *)&UDPLocal,sizeof(UDPLocal));
if(iRet == SOCKET_ERROR)
{
printf("/nUdp2Udp:Bind UDP port %d failed.",asi.LocalPort);
Sleep(5000);
continue;
}
else
printf("/nUdp2Udp:Bind UDP port %d ok.",asi.LocalPort);

// DWORD threadid=GetCurrentThreadId();
struct sockaddr_in from;
int dwSize=sizeof(from);
char incomingbuff[maxsize];
int read = 1;
while(read >0)
{
read=recvfrom(s[0],incomingbuff,maxsize,0,(SOCKADDR *)&from,&dwSize);
if(read <=0 ) break;
s[1] = udpsvrGetSock1(from) ;
if(s[1] == 0)
{
//创建一个UDP socket
s[1]=socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP);
if(s[1]==INVALID_SOCKET)
{
ShowError("/nTcp2Udp:Create UDP socket");
Sleep(5000);
continue;
}
BOOL bindok = FALSE;
int LocalTmpPort = asi.LocalTmpPort;
if(LocalTmpPort<1) LocalTmpPort = 4000;
while(LocalTmpPort <65535)
{
//监听本地UDP port的地址结构
UDPLocal.sin_family=AF_INET;
UDPLocal.sin_addr.s_addr=INADDR_ANY;
UDPLocal.sin_port=htons(LocalTmpPort);
//bind UDP socket
iRet=bind(s[1],(struct sockaddr *)&UDPLocal,sizeof(UDPLocal));
if(iRet == SOCKET_ERROR)
{
printf("/nTcp2Udp:Bind UDP port %d failed.",LocalTmpPort);
LocalTmpPort ++ ;
Sleep(50);
continue;
}
else
{
printf("/nTcp2Udp:Bind UDP port %d ok.",LocalTmpPort);
bindok = TRUE;
break;
}
}
if(!bindok)
{
_DelSock(s[0]);
_DelSock(s[1]);
Sleep(5000);
continue;
}

DATAREDIRDPARAM* ptdataredird = new DATAREDIRDPARAM;
ptdataredird->sock[0] = s[0];//udp
ptdataredird->sock[1] = s[1];//udp
memcpy(&ptdataredird->sinudp ,&from,sizeof(sockaddr_in));
ptdataredird->sinudpisfilled = TRUE;
udpsvrAddDataRedird(ptdataredird);
DATAREDIRDPARAM* ptdataredird2 = new DATAREDIRDPARAM;
memcpy(ptdataredird2,ptdataredird,sizeof(DATAREDIRDPARAM));
DWORD threadid;
HANDLE htcp2udpThread = CreateThread(NULL,0,u2uwaitthread,(LPVOID)ptdataredird2,NULL,&threadid);
CloseHandle(htcp2udpThread);
}
printf("/ntUdp2Tcp: recvfrom %s:%d %d bytes.",inet_ntoa(from.sin_addr),ntohs(from.sin_port),read);
int iUDPRepeat = 3;
int npos=0;
while(npos < read)
{
int nsendcount=sendto(s[1],incomingbuff+npos,read-npos,0,(SOCKADDR *)&Target,sizeof(Target));
if(nsendcount == SOCKET_ERROR)
{
ShowError("sendto");
//重复发送次数自减一
if((iUDPRepeat--)>0)
{
printf("/nUDP2UDP Try %d times to send.",iUDPRepeat);
continue;
}
}
if(nsendcount <= 0 ) return 0;
printf("/nUDP2UDP:sendto %s:%d %d bytes.",inet_ntoa(Target.sin_addr),ntohs(Target.sin_port),nsendcount);
npos += nsendcount;
}
}
udpsvrDelAllDataRedird(s[0]);
printf("/n/n**************OK!Udp2Tcp do next******************/n/n");
}//end of while
return 0;
}
//监护线程
DWORD WINAPI u2uwaitthread(LPVOID lpvoid)
{
DATAREDIRDPARAM* pdrp = (DATAREDIRDPARAM*)lpvoid;
HANDLE hThread;
DWORD id;
hThread = CreateThread(NULL,0,udp2udp,(LPVOID)pdrp,NULL,&id);
_AddThread(hThread);
DWORD waiter;
waiter = WaitForSingleObject(hThread,INFINITE);
udpsvrDelDataRedird(pdrp->sock[1]);
_DelThread(hThread);
printf("/nUdp2Tcp: Socket closed./n");
delete pdrp;
ExitThread(0);
return 0;
}
//
//UDP socket数据转发函数，从s[0]接收数据，转发到s[1]
//
DWORD WINAPI udp2udp(LPVOID lpvoid)
{
DATAREDIRDPARAM *tudp = (DATAREDIRDPARAM*)lpvoid;
SOCKET *s = tudp->sock;

DWORD threadid=GetCurrentThreadId();
printf("/n***New UDP2UDP Thread %d recvfrom %d sendto %d./n",threadid,s[1],s[0]);

struct sockaddr_in from;
int dwSize=sizeof(from);
int iUDPRepeat=3;//UDP发送失败后重复的次数

char incomingbuff[maxsize];
int read = 1;
while(read >0)
{
read=recvfrom(s[1],incomingbuff,maxsize,0,(SOCKADDR *)&from,&dwSize);
if(read <=0 ) break;
printf("/nUDP2UDP[%d] recvfrom %s:%d %d bytes.",threadid,inet_ntoa(from.sin_addr),ntohs(from.sin_port),read);
iUDPRepeat = 3;
int npos=0;
while(npos < read)
{
int nsendcount=sendto(s[0],incomingbuff+npos,read-npos,0,(SOCKADDR *)&tudp->sinudp,sizeof(tudp->sinudp));
if(nsendcount == SOCKET_ERROR)
{
ShowError("sendto");
//重复发送次数自减一
if((iUDPRepeat--)>0)
{
printf("/nUDP2UDP Try %d times to send.",iUDPRepeat);
continue;
}
}
if(nsendcount <= 0 ) return 0;
printf("/nUDP2UDP[%d] sendto %s:%d %d bytes.",threadid,inet_ntoa(tudp->sinudp.sin_addr),ntohs(tudp->sinudp.sin_port),nsendcount);
npos += nsendcount;
}
}
printf("/nUDP2UDP Thread %d LastError %d",threadid,GetLastError());
return 0;
}