Use id instead of ip address to detect echo message

Protocol/Station.cs

@@ -1,166 +1,174 @@
-using DropZone.Utils;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Net;
-using System.Net.NetworkInformation;
-using System.Net.Sockets;
-using System.Text;
-using System.Threading;
-
-namespace DropZone.Protocol
-{
-    public class Station
-    {
-        private const string HeaderPrefix = "DROP_ZONE";
-
-        public string Name { get; }
-        private readonly UdpClient _client;
-        private readonly ThreadWrapper _thread;
-        private readonly Dictionary<string, Neighbor> _neighbors = new Dictionary<string, Neighbor>();
-        private readonly Timer _timer;
-
-        public Action OnNeighborsChanged { get; set; }
-
-        public List<Neighbor> Neighbors
-        {
-            get
-            {
-                lock (this)
-                {
-                    return _neighbors.Values.ToList();
-                }
-            }
-        }
-
-        public Station(string name)
-        {
-            Name = name;
-            _client = new UdpClient();
-            _thread = new ThreadWrapper
-            {
-                DoWork = ScanNeighbors
-            };
-            _timer = new Timer(UpdateNeighborsStatus);
-        }
-
-        public Neighbor GetNeighbor(string address)
-        {
-            lock (this)
-            {
-                var found = _neighbors.Values.FirstOrDefault(neighbor => neighbor.Address == address);
-                return found ?? new Neighbor { Address = address };
-            }
-        }
-
-        private void ScanNeighbors()
-        {
-            var localAddresses = GetAllIPAddresses();
-
-            while (true)
-            {
-                var from = new IPEndPoint(IPAddress.Any, 0);
-                var buffer = _client.Receive(ref from);
-                var header = Encoding.UTF8.GetString(buffer, 0, buffer.Length);
-                var parts = header.Split(new[] { '|' }, 2);
-
-                Debugger.Log("Received broadcast header: " + header);
-
-                if (parts.Length != 2 || parts[0] != HeaderPrefix)
-                    continue;
-
-                var address = from.Address.ToString();
-                if (localAddresses.Contains(address))
-                    continue;
-
-                var name = parts[1];
-                var neighbor = new Neighbor
-                {
-                    Name = name,
-                    LastOnline = DateTime.Now,
-                    Address = address
-                };
-
-                lock (this)
-                {
-                    var oldSize = _neighbors.Count;
-
-                    _neighbors[address] = neighbor;
-
-                    if (oldSize != _neighbors.Count)
-                        OnNeighborsChanged?.Invoke();
-                }
-            }
-        }
-
-        private List<string> GetAllIPAddresses()
-        {
-            var ret = new List<string>();
-            foreach (var netInterface in NetworkInterface.GetAllNetworkInterfaces())
-            {
-                var ipProps = netInterface.GetIPProperties();
-                foreach (var address in ipProps.UnicastAddresses)
-                {
-                    if (address.Address.AddressFamily == AddressFamily.InterNetwork)
-                        ret.Add(address.Address.ToString());
-                }
-            }
-
-            return ret;
-        }
-
-        private void UpdateNeighborsStatus(object state)
-        {
-            Ping();
-
-            lock (this)
-            {
-                var now = DateTime.Now;
-                var pairs = _neighbors.ToArray();
-                foreach (var pair in pairs)
-                {
-                    if (now - pair.Value.LastOnline > Constants.ShortestOnlineTime)
-                    {
-                        _neighbors.Remove(pair.Key);
-                    }
-                }
-
-                if (_neighbors.Count != pairs.Length)
-                    OnNeighborsChanged?.Invoke();
-            }
-        }
-
-        private async void Ping()
-        {
-            var header = $"{HeaderPrefix}|{Name}";
-            var bytes = Encoding.UTF8.GetBytes(header);
-            await _client.SendAsync(bytes, bytes.Length, "255.255.255.255", Constants.StationPort);
-        }
-
-        public void Start()
-        {
-            _client.Client.Bind(new IPEndPoint(IPAddress.Any, Constants.StationPort));
-            _thread.Start();
-            _timer.Change(0, 2000);
-        }
-
-        public void Stop()
-        {
-            _timer.Dispose();
-            _client.Close();
-        }
-
-        public class Neighbor
-        {
-            public string Address { get; set; }
-            public string Name { get; set; }
-            public DateTime LastOnline { get; set; }
-
-            public override string ToString()
-            {
-                var name = string.IsNullOrEmpty(Name) ? "UNKNOWN" : Name;
-                return $"{name} [{Address}]";
-            }
-        }
-    }
+using DropZone.Utils;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net;
+using System.Net.Sockets;
+using System.Text;
+using System.Threading;
+
+namespace DropZone.Protocol
+{
+    public class Station
+    {
+        private const string HeaderPrefix = "DROP_ZONE";
+
+        public string Name { get; }
+        private readonly UdpClient _client;
+        private readonly ThreadWrapper _thread;
+        private readonly Dictionary<string, Neighbor> _neighbors = new Dictionary<string, Neighbor>();
+        private readonly Timer _timer;
+        private readonly string _id;
+
+        public Action OnNeighborsChanged { get; set; }
+
+        public List<Neighbor> Neighbors
+        {
+            get
+            {
+                lock (this)
+                {
+                    return _neighbors.Values.ToList();
+                }
+            }
+        }
+
+        public Station(string name)
+        {
+            Name = name;
+            _id = Guid.NewGuid().ToString();
+            _client = new UdpClient();
+            _thread = new ThreadWrapper
+            {
+                DoWork = ScanNeighbors
+            };
+            _timer = new Timer(UpdateNeighborsStatus);
+        }
+
+        public Neighbor GetNeighbor(string address)
+        {
+            lock (this)
+            {
+                var found = _neighbors.Values.FirstOrDefault(neighbor => neighbor.Address == address);
+                return found ?? new Neighbor { Address = address };
+            }
+        }
+
+        private void ScanNeighbors()
+        {
+            while (true)
+            {
+                var from = new IPEndPoint(IPAddress.Any, 0);
+                var buffer = _client.Receive(ref from);
+                var header = Encoding.UTF8.GetString(buffer, 0, buffer.Length);
+
+                Debugger.Log("Received broadcast header: " + header);
+
+                var pingInfo = PingInfo.Parse(header);
+                if (pingInfo == null || pingInfo.Id == _id)
+                    continue;
+
+                var address = from.Address.ToString();
+                var neighbor = new Neighbor
+                {
+                    Name = pingInfo.Name,
+                    LastOnline = DateTime.Now,
+                    Address = address
+                };
+
+                lock (this)
+                {
+                    var oldSize = _neighbors.Count;
+
+                    _neighbors[address] = neighbor;
+
+                    if (oldSize != _neighbors.Count)
+                        OnNeighborsChanged?.Invoke();
+                }
+            }
+        }
+
+        private void UpdateNeighborsStatus(object state)
+        {
+            Ping();
+
+            lock (this)
+            {
+                var now = DateTime.Now;
+                var pairs = _neighbors.ToArray();
+                foreach (var pair in pairs)
+                {
+                    if (now - pair.Value.LastOnline > Constants.ShortestOnlineTime)
+                    {
+                        _neighbors.Remove(pair.Key);
+                    }
+                }
+
+                if (_neighbors.Count != pairs.Length)
+                    OnNeighborsChanged?.Invoke();
+            }
+        }
+
+        private async void Ping()
+        {
+            var header = new PingInfo { Id = _id, Name = Name }.BuildMessage();
+            var bytes = Encoding.UTF8.GetBytes(header);
+            await _client.SendAsync(bytes, bytes.Length, "255.255.255.255", Constants.StationPort);
+        }
+
+        public void Start()
+        {
+            _client.Client.Bind(new IPEndPoint(IPAddress.Any, Constants.StationPort));
+            _thread.Start();
+            _timer.Change(0, 2000);
+        }
+
+        public void Stop()
+        {
+            _timer.Dispose();
+            _client.Close();
+        }
+
+        public class Neighbor
+        {
+            public string Address { get; set; }
+            public string Name { get; set; }
+            public DateTime LastOnline { get; set; }
+
+            public override string ToString()
+            {
+                var name = string.IsNullOrEmpty(Name) ? "UNKNOWN" : Name;
+                return $"{name} [{Address}]";
+            }
+        }
+
+        private class PingInfo
+        {
+            public string Name { get; set; }
+            public string Id { get; set; }
+
+            public string BuildMessage()
+            {
+                return $"{HeaderPrefix}|{Name}|{Id}";
+            }
+
+            public static PingInfo Parse(string st)
+            {
+                if (string.IsNullOrEmpty(st))
+                    return null;
+
+                var parts = st.Split(new[] { '|' }, 3);
+                if (parts.Length != 3 || parts[0] != HeaderPrefix)
+                    return null;
+
+                var name = parts[1];
+                var id = parts[2];
+                return new PingInfo
+                {
+                    Name = name,
+                    Id = id
+                };
+            }
+        }
+    }
 }