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Author Topic: Connected UDP  (Read 3015 times)

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bugy

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Connected UDP
« on: September 24, 2010, 06:30:40 pm »
Hi,
A few days ago my friend wrote a post concerning using UDP. He was suggested that he should create Connected UDP on his own and also to start a new thread concerning that. So that's what I'm doing now.

We tried to google it, but we didn't find the solution.

This is the modified code. I combined it to a single program in hope that the variable IPClient stores some additional information about the client , but it doesn't seem so.

Code: [Select]

#include <SFML/Network.hpp>
#include <iostream>

using namespace std;
using namespace sf;

void server(int);
void client(int);


IPAddress IPClient;

int main()
{
    cout << "Type: \'s\' to run server or \'c\' to run client." <<endl;
    char input;
    cin >> input;

    if(input == 's')
    {
        server(0);
        client(1);
    }
    else if(input == 'c')
    {
        client(0);
        server(1);
    }

    system("Pause");
}

void server(int param)
{
    SocketUDP Server;

    if(param == 0)
    {
        if (!Server.Bind(10023))
        {
            cout << "Error" << endl;
        }
    }
    else if(param == 1)
    {
        if (!Server.Bind(10024))
        {
            cout << "Error" << endl;
        }
    }


    cout << "Server initialized." << endl;

    IPAddress SenderIP;
    unsigned short SenderPort;
    sf::Packet Packet;

    while (true)
    {
        sf::Socket::Status SocketStatus = Server.Receive(Packet, SenderIP, SenderPort);

        cout << endl <<endl << "Socket status: " << SocketStatus  << endl << "---------------" <<endl;

        if(SocketStatus == sf::Socket::Done)
        {
            // Extract the message and display it
            string message;
            Packet >> message;
            cout << "IP: " << SenderIP << endl << "Port: "<< SenderPort << endl << "Message: " << message<< endl;
            IPClient = SenderIP;
            return;
        }

    }

    Server.Close();
}

void client(int param)
{
    cout << "Client Initialized." << endl;

    int ServPort;
    IPAddress ServIP;

    if(param == 0)
    {    
        IPAddress ServIPBuff("here comes server IP"); // !!!
        ServIP = ServIPBuff;
        ServPort = 10023;
    }
    else if(param == 1)
    {
        ServIP = IPClient;
        ServPort = 10024;
    }

    if (!ServIP.IsValid()){
        cout << "Niepoprawny adres serwera" << endl;
    }

    SocketUDP Client;
    string Message = "Hi, I'm a client !";
    sf::Packet PacketToSend;
    PacketToSend << Message;

    cout << "Press Enter to send packet." <<endl;
    getchar();

    char input = getchar();
    while(input == 10)
    {

        if (Client.Send(PacketToSend, ServIP, ServPort) != Socket::Done)
            cout << "Pierdolony error!" << endl;
        else
            cout << "Message sent to server : \"" << Message << "\"" << endl;

        input = getchar();
        if(input == 'z') break;
    }

    Client.Close();
}



It simply listens for packets in server mode and resends a packet to the client after server receives one.
In client mode it sends a packet (or more) to a server and after you type 'z'. It starts listening for packets sent back from the server.

Everything works fine on LAN. But when I run the server mode on a real server (RPS with public ip) there occurs a problem. Server receives a packet from my computer (non-public, local ip) and than tries to send a packet back. Unfortunately it never is received by my computer.

So how should I modify it to have the effect of Connected UDP?

Bye

Mindiell

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Connected UDP
« Reply #1 on: September 29, 2010, 09:09:17 am »
Excuse me, but you are doing very strange things here...
- When lauching the server, the server is never finishing, so client(1) will never be launched.
- Why stopping the clien to start a server (with z), when launching client ?

What is important is that UDP socket can send and receive, no need to be a server in order to receive packets.
What is meant by "connected UDP" is that your packets must manage a "virtual connexion" between server and client :
- ask to connect to the server
- if authorized, connect effectively
- when deconnecting, send it to the server in order the server deconnect the client
- etc...

So, I would modify your code as this (directly, no verification, there can be some errors ;) ) :
Code: [Select]
int main()
{
    cout << "Type: \'s\' to run server or \'c\' to run client." <<endl;
    char input;
    cin >> input;

    if(input == 's')
    {
        server();
    }
    else if(input == 'c')
    {
        client();
    }
}


Code: [Select]
void server(int param)
{
    SocketUDP Server;

    if (!Server.Bind(10023))
    {
        cout << "Error" << endl;
        return;
    }
    cout << "Server initialized." << endl;

    std::vector<IPAddress> MyClients; // Important : the list of clients connected
    IPAddress SenderIP;
    unsigned short SenderPort;
    sf::Packet Packet;

    while (true)
    {
        if(Server.Receive(Packet, SenderIP, SenderPort) == sf::Socket::Done)
        {
            // Extract the message to know what to do
            string message;
            Packet >> message;

            // Is a new client trying to connect ?
            if (message=="CONN")
            {
            //... Verify that the client is not connected yet  (in our client vector)
            //... If not, verify we are not going over the MAX CLIENT count
            //... If not, send to the client that the connection is ok (message="OK")
            //... Add the IPAddress of the client in our vector
            }
            //A connected client is sending a message
            {
            //... Verify that the client is a connected one (in our client vector)
            //... If not, do nothing or send it something to explain
            //... If yes, ok, you can use the message
            //... If the message is "DECO", then remove the client from the vector, because it just deconnect !
            }
        }
    }
    Server.Close();
}


By the way, you'll need something to close the server properly.
Mindiell
----

bugy

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Connected UDP
« Reply #2 on: October 02, 2010, 04:53:31 pm »
Thanks buddy. It really helped. Now I've got both way working transmission. :)

Bye

 

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