问题描述
我如何获得使用Windows库中的NAT的外部IP地址?我试图找到任何INATExternalIPAddressCallback信息,但只找到用C一个例子++使用不可用接口C#。任何指导,将不胜感激。
How do I get the external IP Address of a NAT using the windows library? I am trying to find any information on INATExternalIPAddressCallback, but have only found one example in C++ using unavailable interfaces to C#. Any guidance would be much appreciated.
-Karl
推荐答案
对不起,我不从Windows使用UPnP服务的现有API回答,但它migh帮助你。
Sorry, that I don't answer with an existing API from Windows that uses the UPNP service, but it migh help you
您也可以使用STUN服务器在互联网上也有很多开放的人,每一个VoIP服务提供商有一个。
You could also use a STUN-server on the internet, there are many open ones, every VOIP provider has one.http://en.wikipedia.org/wiki/STUNhttp://tools.ietf.org/html/rfc3489
如打开一个UDP套接字,连接到stun.gmx.net端口3478和发送的一揽子贷款是这样的:
e.g. open an UDP-socket, connect to stun.gmx.net on port 3478 and send a paket like this:
using System;
using System.Net;
using System.Collections.Generic;
using System.Text;
using System.Security.Cryptography;
namespace xxx
{
class STUNPacket
{
static RNGCryptoServiceProvider m_rand=new RNGCryptoServiceProvider();
private byte[] m_requestid=new byte[16];
public STUNPacket()
{
m_rand.GetBytes(m_requestid);
}
public byte[] CreateRequest()
{
byte[] packet=new byte[0x1c] {
//Header:
0x00,0x01, //Art des STUN-Pakets: 0x0001=Binding Request
0x00,0x08, //Länge des Pakets ohne Header
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, //Transkations-ID
//Message-Attribute:
0x00,0x03, //Typ: Change-Request
0x00,0x04, //Länge: 4 Bytes
0x00,0x00,0x00,0x00 //Weder IP, noch Port ändern
};
for(int i=0;i<16;i++)
packet[i+4]=m_requestid[i];
return packet;
}
public IPEndPoint ParseResponse(byte[] paket)
{
if (paket.Length<20)
throw new Exception("STUN-Response zu kurz, um einen Header zu haben");
if (paket[0]!=1||paket[1]!=1)
throw new Exception("STUN-Reposne hat falschen Typ, muss Binding-Response sein");
for (int i=0;i<16;i++)
if (paket[i+4]!=m_requestid[i])
throw new Exception("STUN-Antwort hat falsche Transkations-ID");
int size=paket[2]*256+paket[3];
int pos=20;
for(;;)
{
if (size<4)
throw new Exception("Verbleibende Nachricht zu kurz für weiteren Attributheader, "+
"Mapped-Adress-Attribut nicht gefunden");
int attrsize=paket[pos+2]*256+paket[pos+3];
if (pos+4+attrsize>paket.Length)
throw new Exception("Attributheader hat Länge, die nicht mehr ins Paket passt");
//Wenn kein Mapped-Adress-Attribut, dann überspringen
if (paket[pos]!=0||paket[pos+1]!=1)
{
pos+=attrsize;
continue;
}
if (attrsize<8)
throw new Exception("Mapped-Adress-Attribut ist zu kurz");
if (paket[pos+5]!=1)
throw new Exception("Adreßfamilie von Mapped-Adress ist nicht IPV4");
int port=paket[pos+6]*256+paket[pos+7];
IPAddress adress=new IPAddress(new byte[4] { paket[pos+8],paket[pos+9],paket[pos+10],paket[pos+11] });
return new IPEndPoint(adress,port);
}
}
}
}
}
由ParseResponse返回的IP地址应该是您的IP地址像外界看到它。
The IP-address returned by ParseResponse should be your ip adress like the outside world sees it.
注意,将不能够得到您的外部IP,无需使用互联网服务器的任何帮助,或直接通过UPnP从服务器
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