iOS Microchip Ethernet Discoverer

I can send/receive with socket as this tutorial

Now, i want to use UDP to discover an embedded device’s IP address when plugged into a DCHP enabled network. With a GUI based iOS app broadcasting a UDP discovery request, embedded devices can receive the request and reply to the iOS app, announcing their presence and IP address on the network.

My app will listen to the PORT 30303 for a discovery request.

This is open source of PC app:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net.Sockets;

namespace Embedded_Device_Discoverer
{
    public partial class Form1 : Form
    {
        public delegate void AsyncCallback(IAsyncResult ar);
        public delegate void AddTolstDiscoveredDevices(object o);

        private UdpState GlobalUDP;

        public Form1()
        {
            InitializeComponent();
        }

        struct UdpState
        {
            public System.Net.IPEndPoint EP;
            public System.Net.Sockets.UdpClient UDPClient;
        }

        private void cmdDiscoverDevices_Click(object sender, EventArgs e)
        {
            try
            {
                // Clear the listbox of all current discovery responses
                listView1.Items.Clear();

                // Try to send the discovery request message
                byte[] DiscoverMsg = Encoding.ASCII.GetBytes("Discovery: Who is out there?");
                GlobalUDP.UDPClient.Send(DiscoverMsg, DiscoverMsg.Length, new System.Net.IPEndPoint(System.Net.IPAddress.Parse("255.255.255.255"), 30303));
            }
            catch
            {
                MessageBox.Show("Unable to transmit discovery message.  Check network connectivity and ensure that no other instances of this program are running.", "Error", MessageBoxButtons.OK);
                return;
            }
        }

        public void AddDiscoveryEntry(object o)
        {
            //lstDiscoveredDevices.Items.Add(o);
            listView1.Items.Add(new ListViewItem(((string)(o)).Split('\n')));
        }

        public void ReceiveCallback(IAsyncResult ar)
        {
            UdpState MyUDP = (UdpState)ar.AsyncState;

            // Obtain the UDP message body and convert it to a string, with remote IP address attached as well
            string ReceiveString = Encoding.ASCII.GetString(MyUDP.UDPClient.EndReceive(ar, ref MyUDP.EP));
            ReceiveString = MyUDP.EP.Address.ToString() + "\n" + ReceiveString.Replace("\r\n", "\n");

            // Configure the UdpClient class to accept more messages, if they arrive
            MyUDP.UDPClient.BeginReceive(ReceiveCallback, MyUDP);

            // Write the received UDP message text to the listbox in a thread-safe manner
            //lstDiscoveredDevices.Invoke(new AddTolstDiscoveredDevices(AddDiscoveryEntry), ReceiveString);
            listView1.Invoke(new AddTolstDiscoveredDevices(AddDiscoveryEntry), ReceiveString);
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            try
            {
                GlobalUDP.UDPClient = new UdpClient();
                GlobalUDP.EP = new System.Net.IPEndPoint(System.Net.IPAddress.Parse("255.255.255.255"), 30303);
                System.Net.IPEndPoint BindEP = new System.Net.IPEndPoint(System.Net.IPAddress.Any, 30303);
                byte[] DiscoverMsg = Encoding.ASCII.GetBytes("Discovery: Who is out there?");

                // Set the local UDP port to listen on
                GlobalUDP.UDPClient.Client.Bind(BindEP);

                // Enable the transmission of broadcast packets without having them be received by ourself
                GlobalUDP.UDPClient.EnableBroadcast = true;
                GlobalUDP.UDPClient.MulticastLoopback = false;

                // Configure ourself to receive discovery responses
                GlobalUDP.UDPClient.BeginReceive(ReceiveCallback, GlobalUDP);

                // Transmit the discovery request message
                GlobalUDP.UDPClient.Send(DiscoverMsg, DiscoverMsg.Length, new System.Net.IPEndPoint(System.Net.IPAddress.Parse("255.255.255.255"), 30303));
            }
            catch
            {
                MessageBox.Show("Unable to transmit discovery message.  Check network connectivity and ensure that no other instances of this program are running.", "Error", MessageBoxButtons.OK);
                return;
            }
        }

        private void listView1_ItemActivate(object sender, EventArgs e)
        {
            System.Diagnostics.Process.Start("http://" + listView1.SelectedItems[0].Text);
        }
    }
}

How can i do it with iOS and Objective C?

Thank you

You can start from here for device discovery

https://github.com/cybergarage/CyberLink4C