Socks 5 UDP connection

Question

I m trying to connect to an UDP Socks5 proxy, but no server will reply to my initial handshake. Wire shark shows that the right signal is going to the server, but no reply is receive

#define PUT_BYTE(ptr,data) (*(unsigned char*)ptr = data)



static int Connect_proxy(SOCKET sock,sockaddr_in Rcv_address) {

char buff[200],*ptr;
sockaddr_in SenderAddrTemp;
int SenderAddrSize= sizeof(SenderAddrTemp);

ptr=buff;
int iResult;

PUT_BYTE(ptr++,5);
PUT_BYTE(ptr++,1);
PUT_BYTE(ptr++,0);  


iResult = sendto(sock,
    buff, ptr-buff, 0, (SOCKADDR *) & Rcv_address, sizeof (Rcv_address));

if (iResult == SOCKET_ERROR) {
    wprintf(L"[Send]Conection request failed with error: %d\n",      WSAGetLastError());
    //closesocket(sock);
    //WSACleanup();
    return -1;

}
iResult = recvfrom(sock,buff, 200, 0, (SOCKADDR *) & SenderAddrTemp, &SenderAddrSize);
if (iResult==-1) { 
    wprintf(L"[Recv] Connection request failed with error: %d\n", WSAGetLastError());
    return -1;
}
else
    if (iResult==2)  {
        wprintf(L"OK");
    }

    return 0;

}

The socket init is :

    iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (iResult != NO_ERROR) {
    wprintf(L"WSAStartup failed with error: %d\n", iResult);
    return 1;
}

//---------------------------------------------
// Create a socket for sending data
SendSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (SendSocket == INVALID_SOCKET) {
    wprintf(L"socket failed with error: %ld\n", WSAGetLastError());
    WSACleanup();
    return 1;
}


RecvAddr.sin_family = AF_INET;
RecvAddr.sin_port = htons(8888);
RecvAddr.sin_addr.s_addr = inet_addr("114.207.246.173");

service.sin_family = AF_INET;
service.sin_addr.s_addr = htonl(INADDR_ANY);
service.sin_port = htons(0);

bind(SendSocket, (SOCKADDR *) &service, sizeof (service));

if (iResult == SOCKET_ERROR) {
    wprintf(L"bind failed with error %u\n", WSAGetLastError());
    closesocket(SendSocket);
    WSACleanup();
    return 1;
}
Connect_proxy(SendSocket,RecvAddr);

Thanks!

Answer 1

Fixed:

Although the socks connection will be UDP, the handshake must be done in TCP

SendSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); //this must became a TCP socket SOCK_STREAM