編輯：經過很多更多的測試，除非啓用UPnP，否則對我來說這似乎不起作用。所以我在這裏寫的很多東西可能會發現很有用，但很多人沒有啓用UPnP（因爲它存在安全風險），所以它不適用於他們。
下面是一些使用PubNub作爲中繼服務器的代碼:)。我不建議在沒有測試的情況下使用此代碼，因爲它不完美（我不確定它是否安全或正確的方式做事？idk我不是網絡專家），但它應該給你一個想法做什麼。它至少在我的愛好項目中爲我工作至今。它缺少的東西是：
- 測試客戶端是否在您的LAN上。我只發送給您的局域網和另一個網絡上的設備，但效率非常低。
- 測試客戶端何時停止偵聽，例如，如果他們關閉了程序。因爲這是UDP，所以它是無狀態的，因此無論我們是否將消息發送到無效，但我們可能不應該這樣做，如果沒有人得到它們
- 我使用Open.NAT以編程方式執行端口轉發，但這可能不起作用在某些設備上。具體來說，它使用的UPnP有點不安全，需要UDP端口1900手動端口轉發。一旦他們這樣做了，它在大多數路由器上都得到支持，但許多人還沒有這樣做。
因此，首先，您需要一種獲取外部和本地IP的方法。這裏是讓你的本地IP代碼：
// From http://stackoverflow.com/questions/6803073/get-local-ip-address
public string GetLocalIp()
{
var host = Dns.GetHostEntry(Dns.GetHostName());
foreach (var ip in host.AddressList)
{
if (ip.AddressFamily == AddressFamily.InterNetwork)
{
return ip.ToString();
}
}
throw new Exception("Failed to get local IP");
}
而且這裏是通過努力，旨在回報您的外部IP一些網站讓你的外部IP一些代碼
public string GetExternalIp()
{
for (int i = 0; i < 2; i++)
{
string res = GetExternalIpWithTimeout(400);
if (res != "")
{
return res;
}
}
throw new Exception("Failed to get external IP");
}
private static string GetExternalIpWithTimeout(int timeoutMillis)
{
string[] sites = new string[] {
"http://ipinfo.io/ip",
"http://icanhazip.com/",
"http://ipof.in/txt",
"http://ifconfig.me/ip",
"http://ipecho.net/plain"
};
foreach (string site in sites)
{
try
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(site);
request.Timeout = timeoutMillis;
using (var webResponse = (HttpWebResponse)request.GetResponse())
{
using (Stream responseStream = webResponse.GetResponseStream())
{
using (StreamReader responseReader = new System.IO.StreamReader(responseStream, Encoding.UTF8))
{
return responseReader.ReadToEnd().Trim();
}
}
}
}
catch
{
continue;
}
}
return "";
}
現在，我們需要找到一個開放端口並將其轉發到外部端口。如上所述，我使用了Open.NAT。首先，您在查看registered UDP ports之後，將您認爲合理的端口列表放在一起。下面是例如幾個：
public static int[] ports = new int[]
{
5283,
5284,
5285,
5286,
5287,
5288,
5289,
5290,
5291,
5292,
5293,
5294,
5295,
5296,
5297
};
現在我們可以通過他們，並希望找到一個循環，是不是在使用使用的端口轉發：
public UdpClient GetUDPClientFromPorts(out Socket portHolder, out string localIp, out int localPort, out string externalIp, out int externalPort)
{
localIp = GetLocalIp();
externalIp = GetExternalIp();
var discoverer = new Open.Nat.NatDiscoverer();
var device = discoverer.DiscoverDeviceAsync().Result;
IPAddress localAddr = IPAddress.Parse(localIp);
int workingPort = -1;
for (int i = 0; i < ports.Length; i++)
{
try
{
// You can alternatively test tcp with nc -vz externalip 5293 in linux and
// udp with nc -vz -u externalip 5293 in linux
Socket tempServer = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
tempServer.Bind(new IPEndPoint(localAddr, ports[i]));
tempServer.Close();
workingPort = ports[i];
break;
}
catch
{
// Binding failed, port is in use, try next one
}
}
if (workingPort == -1)
{
throw new Exception("Failed to connect to a port");
}
int localPort = workingPort;
// You could try a different external port if the below code doesn't work
externalPort = workingPort;
// Mapping ports
device.CreatePortMapAsync(new Open.Nat.Mapping(Open.Nat.Protocol.Udp, localPort, externalPort));
// Bind a socket to our port to "claim" it or cry if someone else is now using it
try
{
portHolder = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
portHolder.Bind(new IPEndPoint(localAddr, localPort));
}
catch
{
throw new Exception("Failed, someone is now using local port: " + localPort);
}
// Make a UDP Client that will use that port
UdpClient udpClient = new UdpClient(localPort);
return udpClient;
}
現在的PubNub中繼服務器代碼（ P2PPeer將在後面定義）。有很多在這裏，所以我不真的會解釋，但有希望的代碼是很清楚，以幫助您瞭解什麼是對
public delegate void NewPeerCallback(P2PPeer newPeer);
public event NewPeerCallback OnNewPeerConnection;
public Pubnub pubnub;
public string pubnubChannelName;
public string localIp;
public string externalIp;
public int localPort;
public int externalPort;
public UdpClient udpClient;
HashSet<string> uniqueIdsPubNubSeen;
object peerLock = new object();
Dictionary<string, P2PPeer> connectedPeers;
string myPeerDataString;
public void InitPubnub(string pubnubPublishKey, string pubnubSubscribeKey, string pubnubChannelName)
{
uniqueIdsPubNubSeen = new HashSet<string>();
connectedPeers = new Dictionary<string, P2PPeer>;
pubnub = new Pubnub(pubnubPublishKey, pubnubSubscribeKey);
myPeerDataString = localIp + " " + externalIp + " " + localPort + " " + externalPort + " " + pubnub.SessionUUID;
this.pubnubChannelName = pubnubChannelName;
pubnub.Subscribe<string>(
pubnubChannelName,
OnPubNubMessage,
OnPubNubConnect,
OnPubNubError);
return pubnub;
}
//// Subscribe callbacks
void OnPubNubConnect(string res)
{
pubnub.Publish<string>(pubnubChannelName, connectionDataString, OnPubNubTheyGotMessage, OnPubNubMessageFailed);
}
void OnPubNubError(PubnubClientError clientError)
{
throw new Exception("PubNub error on subscribe: " + clientError.Message);
}
void OnPubNubMessage(string message)
{
// The message will be the string ["localIp externalIp localPort externalPort","messageId","channelName"]
string[] splitMessage = message.Trim().Substring(1, message.Length - 2).Split(new char[] { ',' });
string peerDataString = splitMessage[0].Trim().Substring(1, splitMessage[0].Trim().Length - 2);
// If you want these, I don't need them
//string peerMessageId = splitMessage[1].Trim().Substring(1, splitMessage[1].Trim().Length - 2);
//string channelName = splitMessage[2].Trim().Substring(1, splitMessage[2].Trim().Length - 2);
string[] pieces = peerDataString.Split(new char[] { ' ', '\t' });
string peerLocalIp = pieces[0].Trim();
string peerExternalIp = pieces[1].Trim();
string peerLocalPort = int.Parse(pieces[2].Trim());
string peerExternalPort = int.Parse(pieces[3].Trim());
string peerPubnubUniqueId = pieces[4].Trim();
pubNubUniqueId = pieces[4].Trim();
// If you are on the same device then you have to do this for it to work idk why
if (peerLocalIp == localIp && peerExternalIp == externalIp)
{
peerLocalIp = "127.0.0.1";
}
// From me, ignore
if (peerPubnubUniqueId == pubnub.SessionUUID)
{
return;
}
// We haven't set up our connection yet, what are we doing
if (udpClient == null)
{
return;
}
// From someone else
IPEndPoint peerEndPoint = new IPEndPoint(IPAddress.Parse(peerExternalIp), peerExternalPort);
IPEndPoint peerEndPointLocal = new IPEndPoint(IPAddress.Parse(peerLocalIp), peerLocalPort);
// First time we have heard from them
if (!uniqueIdsPubNubSeen.Contains(peerPubnubUniqueId))
{
uniqueIdsPubNubSeen.Add(peerPubnubUniqueId);
// Dummy messages to do UDP hole punching, these may or may not go through and that is fine
udpClient.Send(new byte[10], 10, peerEndPoint);
udpClient.Send(new byte[10], 10, peerEndPointLocal); // This is if they are on a LAN, we will try both
pubnub.Publish<string>(pubnubChannelName, myPeerDataString, OnPubNubTheyGotMessage, OnPubNubMessageFailed);
}
// Second time we have heard from them, after then we don't care because we are connected
else if (!connectedPeers.ContainsKey(peerPubnubUniqueId))
{
//bool isOnLan = IsOnLan(IPAddress.Parse(peerExternalIp)); TODO, this would be nice to test for
bool isOnLan = false; // For now we will just do things for both
P2PPeer peer = new P2PPeer(peerLocalIp, peerExternalIp, peerLocalPort, peerExternalPort, this, isOnLan);
lock (peerLock)
{
connectedPeers.Add(peerPubnubUniqueId, peer);
}
// More dummy messages because why not
udpClient.Send(new byte[10], 10, peerEndPoint);
udpClient.Send(new byte[10], 10, peerEndPointLocal);
pubnub.Publish<string>(pubnubChannelName, connectionDataString, OnPubNubTheyGotMessage, OnPubNubMessageFailed);
if (OnNewPeerConnection != null)
{
OnNewPeerConnection(peer);
}
}
}
//// Publish callbacks
void OnPubNubTheyGotMessage(object result)
{
}
void OnPubNubMessageFailed(PubnubClientError clientError)
{
throw new Exception("PubNub error on publish: " + clientError.Message);
}
去這裏是一個P2PPeer
public class P2PPeer
{
public string localIp;
public string externalIp;
public int localPort;
public int externalPort;
public bool isOnLan;
P2PClient client;
public delegate void ReceivedBytesFromPeerCallback(byte[] bytes);
public event ReceivedBytesFromPeerCallback OnReceivedBytesFromPeer;
public P2PPeer(string localIp, string externalIp, int localPort, int externalPort, P2PClient client, bool isOnLan)
{
this.localIp = localIp;
this.externalIp = externalIp;
this.localPort = localPort;
this.externalPort = externalPort;
this.client = client;
this.isOnLan = isOnLan;
if (isOnLan)
{
IPEndPoint endPointLocal = new IPEndPoint(IPAddress.Parse(localIp), localPort);
Thread localListener = new Thread(() => ReceiveMessage(endPointLocal));
localListener.IsBackground = true;
localListener.Start();
}
else
{
IPEndPoint endPoint = new IPEndPoint(IPAddress.Parse(externalIp), externalPort);
Thread externalListener = new Thread(() => ReceiveMessage(endPoint));
externalListener.IsBackground = true;
externalListener.Start();
}
}
public void SendBytes(byte[] data)
{
if (client.udpClient == null)
{
throw new Exception("P2PClient doesn't have a udpSocket open anymore");
}
//if (isOnLan) // This would work but I'm not sure how to test if they are on LAN so I'll just use both for now
{
client.udpClient.Send(data, data.Length, new IPEndPoint(IPAddress.Parse(localIp), localPort));
}
//else
{
client.udpClient.Send(data, data.Length, new IPEndPoint(IPAddress.Parse(externalIp), externalPort));
}
}
// Encoded in UTF8
public void SendString(string str)
{
SendBytes(System.Text.Encoding.UTF8.GetBytes(str));
}
void ReceiveMessage(IPEndPoint endPoint)
{
while (client.udpClient != null)
{
byte[] message = client.udpClient.Receive(ref endPoint);
if (OnReceivedBytesFromPeer != null)
{
OnReceivedBytesFromPeer(message);
}
//string receiveString = Encoding.UTF8.GetString(message);
//Console.Log("got: " + receiveString);
}
}
}
最後，這裏是我所有usings：
using PubNubMessaging.Core; // Get from PubNub GitHub for C#, I used the Unity3D library
using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Net.Sockets;
using System.Text;
using System.Threading;
我打開的意見和問題，隨時給反饋，如果這裏的東西是不好的做法，或不工作。從我的代碼翻譯中引入了一些錯誤，我最終會在這裏修復這些錯誤，但這至少應該讓您知道該怎麼做。
如何處理有關IP或端口的數據包丟失的情況？ – user1914692 2014-07-07 16:36:23