How can I activate UDP forwarding for USB communication between a PC and an Android app

I have an real Android device connected to a computer via USB. I managed to activate TCP port forwarding with adb forward tcp:<port> tcp:<port> and successfully communicate with sockets but I don't know how to do the same for UDP.

EDIT : I launched my application on the emulator and typed telnet localhost 5554 and redir add udp:<port>:<port> and it
worked, my function executeCMD is functionnal because when I try ls
it's working.

Some websites said to use redir like this redir add udp:<port>:<port> but when I do so I obtain an error :

usage:


 redir --lport=<n> --cport=<n> [options]


 redir --inetd --cport=<n>




 Options are:-


  --lport=<n>
  port to listen on


  --laddr=IP

address of interface to listen on


  --cport=<n>
  port to connect to


  --caddr=<host>

remote host to connect to


  --inetd
  run from inetd


  --debug
  output debugging info


  --timeout=<n>
set timeout to n seconds


  --syslog
 log messages to syslog


  --name=<str>
 tag syslog messages with 'str'


  --connect=<str> CONNECT string passed to proxy server


  --bind_addr=IP  bind() outgoing IP to given addr


  --ftp=<type>

  redirect ftp connections


where type is either port, pasv, both


  --transproxy
 run in linux's transparent proxy mode


  --bufsize=<octets>  size of the buffer


  --max_bandwidth=<bit-per-sec>
limit the bandwidth


  --random_wait=<millisec>
 wait before each packet


  --wait_in_out=<flag>
 1 wait for in, 2 out, 3 in&out




 Version 2.2.1.

Then I thought this command should be launch on the Android device so I created this method :

 public String executeCMD(String cmd){



 StringBuffer output = new StringBuffer();



 try{



  Process process = Runtime.getRuntime().exec(cmd);



  BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));



  int read;


  char[] buffer = new char[4096];


  while ((read = reader.read(buffer)) > 0) output.append(buffer, 0, read);





  reader.close();



  process.waitFor();





 
}
 catch(IOException e){
 e.printStackTrace();



 
}
 catch(InterruptedException e){
 e.printStackTrace();
 
}





 return output.toString();



}

And when I called it like that :

executeCMD("redir add udp:" + UDP_PORT + ":" + UDP_PORT)

I get no output and the UDP server on the Android app can't communicate with the UDP client.

So I'm a bit lost... I'll continue searching but If you can help me; go ahead.

Thanks.