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//
// Authors:
// Alan McGovern alan.mcgovern@gmail.com
// Ben Motmans <ben.motmans@gmail.com>
// Nicholas Terry <nick.i.terry@gmail.com>
//
// Copyright (C) 2006 Alan McGovern
// Copyright (C) 2007 Ben Motmans
// Copyright (C) 2014 Nicholas Terry
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System;
using System.Collections.Generic;
using System.Text;
using System.Net;
using Mono.Nat.Pmp;
using System.Net.NetworkInformation;
using System.Net.Sockets;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using System.Linq;
namespace Mono.Nat
{
internal class PmpSearcher : ISearcher, IDisposable
{
private ILogger _logger;
private int timeout = 250;
private DateTime nextSearch;
public event EventHandler<DeviceEventArgs> DeviceFound;
public PmpSearcher(ILogger logger)
{
_logger = logger;
CreateSocketsAndAddGateways();
}
public void Dispose()
{
var list = sockets.ToList();
sockets.Clear();
foreach (var s in list)
{
using (s)
{
s.Close();
}
}
}
private List<UdpClient> sockets;
private Dictionary<UdpClient, List<IPEndPoint>> gatewayLists;
private void CreateSocketsAndAddGateways()
{
sockets = new List<UdpClient>();
gatewayLists = new Dictionary<UdpClient, List<IPEndPoint>>();
try
{
foreach (NetworkInterface n in NetworkInterface.GetAllNetworkInterfaces())
{
if (n.OperationalStatus != OperationalStatus.Up && n.OperationalStatus != OperationalStatus.Unknown)
continue;
IPInterfaceProperties properties = n.GetIPProperties();
List<IPEndPoint> gatewayList = new List<IPEndPoint>();
foreach (GatewayIPAddressInformation gateway in properties.GatewayAddresses)
{
if (gateway.Address.AddressFamily == AddressFamily.InterNetwork)
{
gatewayList.Add(new IPEndPoint(gateway.Address, PmpConstants.ServerPort));
}
}
if (gatewayList.Count == 0)
{
/* Mono on OSX doesn't give any gateway addresses, so check DNS entries */
foreach (var gw2 in properties.DnsAddresses)
{
if (gw2.AddressFamily == AddressFamily.InterNetwork)
{
gatewayList.Add(new IPEndPoint(gw2, PmpConstants.ServerPort));
}
}
foreach (var unicast in properties.UnicastAddresses)
{
if (/*unicast.DuplicateAddressDetectionState == DuplicateAddressDetectionState.Preferred
&& unicast.AddressPreferredLifetime != UInt32.MaxValue
&& */unicast.Address.AddressFamily == AddressFamily.InterNetwork)
{
var bytes = unicast.Address.GetAddressBytes();
bytes[3] = 1;
gatewayList.Add(new IPEndPoint(new IPAddress(bytes), PmpConstants.ServerPort));
}
}
}
if (gatewayList.Count > 0)
{
foreach (UnicastIPAddressInformation address in properties.UnicastAddresses)
{
if (address.Address.AddressFamily == AddressFamily.InterNetwork)
{
UdpClient client;
try
{
client = new UdpClient(new IPEndPoint(address.Address, 0));
}
catch (SocketException)
{
continue; // Move on to the next address.
}
gatewayLists.Add(client, gatewayList);
sockets.Add(client);
}
}
}
}
}
catch (Exception)
{
// NAT-PMP does not use multicast, so there isn't really a good fallback.
}
}
public async void Search()
{
foreach (UdpClient s in sockets)
{
try
{
await Search(s).ConfigureAwait(false);
}
catch
{
// Ignore any search errors
}
}
}
async Task Search(UdpClient client)
{
// Sort out the time for the next search first. The spec says the
// timeout should double after each attempt. Once it reaches 64 seconds
// (and that attempt fails), assume no devices available
nextSearch = DateTime.Now.AddMilliseconds(timeout);
timeout *= 2;
// We've tried 9 times as per spec, try searching again in 5 minutes
if (timeout == 128 * 1000)
{
timeout = 250;
nextSearch = DateTime.Now.AddMinutes(10);
return;
}
// The nat-pmp search message. Must be sent to GatewayIP:53531
byte[] buffer = new byte[] { PmpConstants.Version, PmpConstants.OperationCode };
foreach (IPEndPoint gatewayEndpoint in gatewayLists[client])
{
await client.SendAsync(buffer, buffer.Length, gatewayEndpoint).ConfigureAwait(false);
}
}
bool IsSearchAddress(IPAddress address)
{
foreach (List<IPEndPoint> gatewayList in gatewayLists.Values)
foreach (IPEndPoint gatewayEndpoint in gatewayList)
if (gatewayEndpoint.Address.Equals(address))
return true;
return false;
}
public void Handle(IPAddress localAddress, byte[] response, IPEndPoint endpoint)
{
if (!IsSearchAddress(endpoint.Address))
return;
if (response.Length != 12)
return;
if (response[0] != PmpConstants.Version)
return;
if (response[1] != PmpConstants.ServerNoop)
return;
int errorcode = IPAddress.NetworkToHostOrder(BitConverter.ToInt16(response, 2));
if (errorcode != 0)
_logger.LogDebug("Non zero error: {0}", errorcode);
IPAddress publicIp = new IPAddress(new byte[] { response[8], response[9], response[10], response[11] });
nextSearch = DateTime.Now.AddMinutes(5);
timeout = 250;
OnDeviceFound(new DeviceEventArgs(new PmpNatDevice(endpoint.Address, publicIp, _logger)));
}
public DateTime NextSearch
{
get { return nextSearch; }
}
private void OnDeviceFound(DeviceEventArgs args)
{
if (DeviceFound != null)
DeviceFound(this, args);
}
public NatProtocol Protocol
{
get { return NatProtocol.Pmp; }
}
}
}
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