Getting basic UDP example working?

[Patrickyp]

Hi, Not really an issue but I am a newbie c++ programmer trying to get a very basic UDP communication example working. I am running echo_server.cpp on 1 computer and echo_client_conn.cpp on another computer. I am getting

input: Error while reading! (Connection refused)

when I run the client program. The server program doesn't seem to be giving error. Can you help me diagnose what is the issue? I did not change anything besides the host value. Also ping to the server from client works. Thanks!

# include <iostream>
# include "../headers/inetserverdgram.hpp"
# include "../headers/exception.hpp"
# include <cstring>

// Server for echo_client_*.cpp
// simply receives a message and sends an answer.

int main(void)
{
    using std::string;

    string host = "192.168.0.111"; //ip address of server computer
    string port = "1234";

    string answer("Hello back from the server!");
    string from;
    string fromport;
    string buf;

    buf.resize(32);

    try {
	libsocket::inet_dgram_server srv(host,port,LIBSOCKET_BOTH);

	for (;;)
	{
	    srv.rcvfrom(buf,from,fromport);

	    std::cout << "Datagram from " << from << ":" << fromport << " " << buf << std::endl;

	    srv.sndto(answer,from,fromport);
	}

	srv.destroy();
    } catch (const libsocket::socket_exception& exc)
    {
	std::cerr << exc.mesg;
    }


    return 0;
}

client code
# include <iostream>
# include <unistd.h>
# include "../headers/inetclientdgram.hpp"
# include "../headers/exception.hpp"

/*
 * Sends and receives messages via connected UDP sockets
 */

int main(void)
{
    using std::string;

    string host = "192.168.0.111";//also put address of server here?
    string port = "1234";

    string answer;

    answer.resize(32);

    libsocket::inet_dgram_client sock(LIBSOCKET_IPv4);

    try {
	std::cout << sock.gethost();
    } catch (const libsocket::socket_exception& exc)
    {
	std::cerr << exc.mesg;
    }

    try {
	for ( int i = 0; i < 20; i++ )
	{
	    sock.connect(host,port);

	    sock << "Hello, server";

	    sock >> answer;

	    std::cout << "Answer from server: " << answer << std::endl;

	    sock.deconnect();
	}
    } catch ( const libsocket::socket_exception& exc )
    {
	std::cerr << exc.mesg;
    }

    sock.destroy();

    return 0;
}

[Patrickyp]

Now I have the following error on my server side:

/home/pi/gitlibs/inetdgram.cpp:88: inet_dgram_rcvfrom() - recvfrom() failed -- could not receive data from peer! (Success!)

Client seems to be running on infinite loop still.

[dermesser]

Do you have any firewall or network restrictions in place? Does it work when running server and client on the same machine?