I am developing a peer to peer call. I am using de.javawi.jstun.test .
I found this constructor in de.javawi.jstun.test.DiscoveryTest .
public DiscoveryTest(InetAddress sourceIaddress, int sourcePort, String stunServer, int stunServerPort) {
this.sourceIaddress = sourceIaddress;
this.sourcePort = sourcePort;
this.stunServer = stunServer;
this.stunServerPort = stunServerPort;
}
My question is What is the difference between the Source Port and the StunServerPort??
stunServerPort is the port the STUN server listens on for incoming binding requests. This is typically one of the standard STUN ports: 3478 or 3479.
sourcePort is the port the client behind a NAT has obtained locally to create a socket with. Most often, the client attempting to do P2P will ask the OS to randomly pick an available local port to send/receive from. You can probably pass 0 for sourcePort and let it pick the port for you as well. Or if you already have a socket, use the same port as your local, and DiscoveryTest will set the reuseaddr flag so it can have a socket co-exist.
Related
I've implemented a Xamarin app that successfully peers to another instance of itself running on another device using WiFiP2PManager, OnPeersAvailable and OnConnectionInfoAvailable (etc.).
My challenge now is I'd like the group owner to specify the PORT the client(s) will use to connect.
SERVER
var serverSocket = new ServerSocket(port); <<< PASS THIS PORT NUMBER TO THE CLIENT.
client = serverSocket.Accept();
CLIENT
client = new Socket();
InetSocketAddress socketAddress = new InetSocketAddress(address, port); <<< PORT PASSED FROM THE SERVER
client.Connect(socketAddress);
Is there any way I can pass additional information to the peer that it can use for connection, such as the port number?
Thanks
-John
I want to make 2 devices communicate via sockets.
I use this code for the client socket:
Socket socket = Gdx.net.newClientSocket(Net.Protocol.TCP, adress, 1337, socketHints);
(SocketHints: timeout = 4000)
I get a GdxRuntimeException each time this line is being executed. What is wrong with the socket?
Screenshot of stack trace
You get that message because the socket couldn't be opened.
Note the last line about the return in the API:
newClientSocket:
Socket newClientSocket(Net.Protocol protocol,
java.lang.String host,
int port,
SocketHints hints)
Creates a new TCP client socket that connects to the given host and port.
Parameters:
host - the host address
port - the port
hints - additional SocketHints used to create the socket. Input null to use the default setting provided by the system.
Returns:
GdxRuntimeException in case the socket couldn't be opened
Try doing some debugging to find out why you are getting this error.
Is the port already in use? Are you trying to open more than one connection on the same port? Is the server IP valid? Maybe something else is causing the issue?
I want to setup a datastreaming server in Processing, so the Client sends a String to the Server and the Server answeres it. For example Client - Server "Cupcake" then Server - Client "Cupcakce sounds funny" so the Server answeres the string. I tried this with the UDP library and opened the port on the server. But when the server had to answer the Clinet it did'nt work, because I can't open the client's ports. Any solutions?
Sounds like you need two-way communication.
Using UDP you would need two sketches that are both UDP servers and clients.
e.g.
sketch #1 listens on port 12000
sketch #1 sends data on port 12001
sketch #2 listens on port 12001
sketch #2 sends data on port 12000
You can also use TCP sockets.
As the Server you can use Examples > Libraries > Network > ChatServer
I'm surprised there's no ChatClient example, but you can get away with something like this:
import javax.swing.*;
import processing.net.*;
int port = 10002;
Client myClient;
void setup()
{
size(400, 400);
textFont(createFont("SanSerif", 16));
myClient = new Client(this, "localhost", port); // Starts a client on port 10002
background(0);
}
void draw()
{
background(0);
text("client - press ENTER to type\nconnected:"+myClient.active(), 15, 45);
}
void keyReleased() {
if (keyCode == ENTER) {
String message = JOptionPane.showInputDialog(null, "message: ", "TCP Client messaging", JOptionPane.QUESTION_MESSAGE);
println(message);
if (myClient.active() && message != null) {
myClient.write(message);
}
}
}
Note: The server must be running before the client so the client can connect.
Be sure to checkout the difference between UDP and TCP protocols to work out which one makes most sense to use in your case (especially if you pan to use more clients).
Another option worth looking into is WebSockets. This would allow you to have a WebSocket server in Processing and the client could either be another Processing sketch or simply any browser with WebSocket support(e.g. most modern)
I'm currently starting a Tcl socket server like this:
socket -server Server 0
This lets the operating system pick an available port to start listening on. The question is that I don't want it to pick any port between 1025 and 64k, instead want to know if I can specify a range of ports? Something like this:
socket -server Server 40000-41000
And then the operating system would pick an available port between 40000 and 41000 for the server to listen on. Is there a way to do this? I can't find it in the Tcl API, but is there some nice API call way to do it rather than iterating through the port range until finding an available port?
The OS itself doesn't provide an API capable of doing that, and Tcl doesn't wrap one up for you as it is actually a pretty rare requirement. Conventionally, servers either listen on specific ports (so clients can know exactly what service to ask for; e.g., 21 for FTP, 22 for SSH, 25 for SMTP, 80 for HTTP, 161 for SNMP, 443 for HTTPS, 993 for secure IMAP) or the clients have some other way of being told what to ask for and genuinely any port will do (0 is the special “pick a card, any card” address). You can ask a Tcl server socket for what port it is actually using fconfigure:
set portNumber [lindex [fconfigure $socket -sockname] 2]
But to get a server socket on a port in a specific range? No API for that. We have to cook something ourselves:
for {set port 40000} {$port <= 41000} {incr port} {
if {![catch {
set sock [socket -server $yourHandler $port]
}]} then {
break
}
}
# If we failed...
if {![info exist sock]} {
error "No ports free in range 40k-41k"
}
This works because failing to bind the port will make the socket creation fail (neatly, catchably) and you can then try to bind the next port. It will take a while to scan over the port range, but it will work.
It's probably neater to wrap this up in a procedure. And Tcl 8.6's try construct will make the code a little less obscure:
proc portInRange {from to handler} {
for {set p $from} {$p <= $to} {incr p} {
try {
return [socket -server $handler $p]
} on error {} continue
}
error "No ports free in range $from-$to"
}
No, there's no API for that.
Generally servers listen on a specific port so that the clients can find the server. So such an API is not particularly useful.
Best to just write it yourself.
I would like to fetch the IP address and port number of an incoming TCP/IP connection. Unfortunately gen_tcp's accept and recv functions only give back a socket, while gen_udp's recv function also gives back the address information. Is there a straightforward way to collect address information belonging to a socket in Erlang?
You need inet/peername 1. From the Erlang inet docs:
peername(Socket) -> {ok, {Address, Port}} | {error, posix()}
Types:
Socket = socket()
Address = ip_address()
Port = int()
Returns the address and port for the other end of a connection.