public void GetHostEntryCallback(IAsyncResult ar)
{
try
{
DNSCbContext ct = (DNSCbContext)ar.AsyncState;
IPHostEntry ipHostInfo = Dns.EndGetHostEntry(ar);
IPAddress ipAddress = ipHostInfo.AddressList[0];
DNSCache.GetInstence().Put(ct.host, ipAddress);
IPEndPoint remoteEP = new IPEndPoint(ipAddress, ct.port);
remote = new Socket(ipAddress.AddressFamily,
SocketType.Stream, ProtocolType.Tcp);
remote.BeginConnect(remoteEP,
new AsyncCallback(remoteConnectCallback), null);
}
catch (Exception)
{
try
{
DNSCbContext ct = (DNSCbContext)ar.AsyncState;
Console.WriteLine("Unknow Host " + ct.host);
this.Close();
}
catch (Exception)
{
//already recycle
}
}
}
public static DNSCache GetInstence()
{
if (instence == null)
{
instence = new DNSCache();
}
return instence;
}
public static DNSCache GetInstence()
{
if (instence == null)
{
instence = new DNSCache();
}
return(instence);
}
//Single thread
private void handshakeReceiveCallback(IAsyncResult ar)
{
//this check is moved to except
//try
//{
// //already recycle
// lock (this)
// {
// if (closed)
// return;
// }
//}
//catch (Exception)
//{
// return;
//}
try
{
int bytesRead = connection.EndReceive(ar);
if (bytesRead == 0)
{
throw new Exception("Error When handshakeReceiveCallback");
}
//Console.WriteLine("bytesRead" + bytesRead.ToString() + " stage" + stage.ToString());
if (stage == 0)
{
//recv numbers of ivlen data
byte[] iv = encryptor.Decrypt(this.connetionBuffer, bytesRead);
//Decrypt sucessful
//iv
stage = 1;
connection.BeginReceive(this.connetionBuffer, 0, 1, 0,
new AsyncCallback(handshakeReceiveCallback), null);
}
else if (stage == 1)
{
byte[] buff = encryptor.Decrypt(this.connetionBuffer, bytesRead);
//Decrypt sucessful
//addrtype
char addrtype = (char)buff[0];
if (addrtype == 1)
{
//type of ipv4
stage = 4;
connection.BeginReceive(this.connetionBuffer, 0, 4, 0,
new AsyncCallback(handshakeReceiveCallback), addrtype);
}
else if (addrtype == 3)
{
//type of url
stage = 3;
connection.BeginReceive(this.connetionBuffer, 0, 1, 0,
new AsyncCallback(handshakeReceiveCallback), addrtype);
}
else if (addrtype == 4)
{
//type of ipv6
stage = 4;
connection.BeginReceive(this.connetionBuffer, 0, 16, 0,
new AsyncCallback(handshakeReceiveCallback), addrtype);
}
else
{
throw new Exception("Error Socket5 AddrType");
}
}
else if (stage == 3)
{
//addr len
byte[] buff = encryptor.Decrypt(this.connetionBuffer, bytesRead);
stage = 4;
//recv addr
connection.BeginReceive(this.connetionBuffer, 0, buff[0], 0,
new AsyncCallback(handshakeReceiveCallback), ar.AsyncState);
}
else if (stage == 4)
{
//addr
byte[] buff = encryptor.Decrypt(this.connetionBuffer, bytesRead);
if (1 == (char)ar.AsyncState)
{
//ipv4
destAddr = string.Format("{0:D}.{1:D}.{2:D}.{3:D}", buff[0], buff[1], buff[2], buff[3]);
}
else if (3 == (char)ar.AsyncState)
{
//ipv6 url
destAddr = ASCIIEncoding.Default.GetString(buff);
}
else
{
//url
destAddr = string.Format("[{0:x2}{1:x2}:{2:x2}{3:x2}:{4:x2}{5:x2}:{6:x2}{7:x2}:{8:x2}{9:x2}:{10:x2}{11:x2}:{12:x2}{13:x2}:{14:x2}{15:x2}]"
, buff[0], buff[1], buff[2], buff[3], buff[4], buff[5], buff[6], buff[7], buff[8], buff[9], buff[10], buff[11], buff[12], buff[13], buff[14], buff[15]);
}
stage = 5;
//recv port
connection.BeginReceive(this.connetionBuffer, 0, 2, 0,
new AsyncCallback(handshakeReceiveCallback), null);
}
else if (stage == 5)
{
//port
byte[] buff = encryptor.Decrypt(this.connetionBuffer, bytesRead);
int port = (int)(buff[0] << 8) + (int)buff[1];
stage = 6;
//handshake completed
lock (timeOutTimer)
{
this.timeOutTimer.Dispose();
timeOutTimer = null;
}
//Begin to connect remote
IPAddress ipAddress;
bool parsed = IPAddress.TryParse(destAddr, out ipAddress);
if (!parsed)
{
IPAddress cache_ipAddress = DNSCache.GetInstence().Get(destAddr);
if (cache_ipAddress == null)
{
DNSCbContext ct = new DNSCbContext(destAddr, port);
Dns.BeginGetHostEntry(destAddr, new AsyncCallback(GetHostEntryCallback), ct);
return;
}
ipAddress = cache_ipAddress;
}
IPEndPoint remoteEP = new IPEndPoint(ipAddress, port);
remote = new Socket(ipAddress.AddressFamily,
SocketType.Stream, ProtocolType.Tcp);
remote.BeginConnect(remoteEP,
new AsyncCallback(remoteConnectCallback), null);
}
}
catch (Exception e)
{
try
{
//handshake time out
lock (timeOutTimer)
{
if (timeOutTimer != null)
{
this.timeOutTimer.Dispose();
}
timeOutTimer = null;
}
Console.WriteLine(e.ToString());
this.Close();
}
catch (Exception)
{
//already recycle
}
}
}
