将C＃客户端连接到C ++服务器

Question

I just can't get it to work, I'm frustrated.

My C++ code ( _details is addrinfo* and _socket is SOCKET ):

struct addrinfo hints;
_socket = socket(AF_INET, SOCK_STREAM, 0);
if (_socket < 0)
    throw "Invalid socket";
ZeroMemory(&hints, sizeof(hints));
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
hints.ai_flags = AI_PASSIVE;


if (getaddrinfo(NULL, Port.c_str(), &hints, &_details) != 0)
{
    throw "GetAddrInfo failed";
}

if ((bind(_socket, _details->ai_addr, this->_details->ai_addrlen)) != 0)
{
    throw "Bind Unsuccessful";
}

freeaddrinfo(this->_details);
if (listen(this->_socket, SOMAXCONN) != 0)
        throw "Listen Unsuccessful";
client = accept(this->_socket, (struct sockaddr*)&client_addr, &addrlen);

A simple C++ server. C++ and Python clients work perfectly with the above server, and doing everything as expected.

Then comes the client:

        Socket s;

        IPAddress ip = Dns.GetHostEntry("127.0.0.1").AddressList[0];
        int port = 7777;
        IPEndPoint remoteEP = new IPEndPoint(ip, port);

        s = new Socket(AddressFamily.InterNetworkV6,
            SocketType.Stream, ProtocolType.Tcp);

        bool isConnected = false;
        while (!isConnected)
        {
            try
            {
                s.Connect(remoteEP);
                isConnected = true;
            }
            catch (Exception e1)
            {
                System.Threading.Thread.Sleep(2000);
            }
        }

The C# client works perfectly with a C# server.

Each of these work, together - they just don't. I try to connect to the server but the client always ends up throwing System.Net.Sockets SocketException with the error code of 10061 , claiming that the C++ server rejects it.

One thread on SO asked a similar question, receiving the answer that he should sleep after every connection request and then try again (as you can see, done already).

Another thread, on another site, claimed that the problem is in the server and that he converted the C++ server parameters from host byte order to network byte order:

listenSocketAddress.sin_port = htons((u_short)port);
listenSocketAddress.sin_addr.S_un.S_addr = htonl(INADDR_ANY);

but I use addrinfo which doesn't contain the same variables as sockaddr_in .

How can I connect those two?

Answer 1

As far as I can tell, your C++ side is using IPv4 ( AF_INET ), while your C# side is using IPv6 ( AddressFamily.InterNetworkV6 ). Either change the server to use IPv6, or change the client to use IPv4. Or ideally, let them use whichever works best, and use hostnames instead of IP addresses.