C#实现同步模式下的端口映射程序
今天打算写一个FtpServer玩一下的,需要看看ftp软件常用命令形式(完整实现所有ftp命令太麻烦),最开始打算通过抓包看cuteftp是如何访问ftpserver的,但要把其中的命令保存下来还得一条条复制,太麻烦,便通过proxy模式写了一个代理程序,来获取其交互的命令,写了一个简单的同步模式下的端口映射程序后,发现比常用的异步proxy要简单的多,便把这段代码贴出来,以备日后查询:
class Program { static void Main(string[] args) { TcpListener listener = new TcpListener(new IPEndPoint(IPAddress.Loopback, 8000)); listener.Start(); while (true) { var client = listener.AcceptTcpClient(); Console.WriteLine("connected"); var proxy = new TcpClient(); Console.WriteLine("remote connected"); proxy.Connect(new IPEndPoint(IPAddress.Loopback, 21)); new SyncProxy("client->remote",proxy.GetStream(), client.GetStream()); new SyncProxy("remote->client",client.GetStream(), proxy.GetStream()); } } } class SyncProxy { NetworkStream read; NetworkStream write; string name; public SyncProxy(string name, NetworkStream read,NetworkStream write) { this.name = name; this.read = read; this.write = write; System.Threading.ThreadPool.QueueUserWorkItem(PipeStream); } void PipeStream(object state) { byte[] buffer = new byte[1500]; int count = 0; while (true) { try { count = read.Read(buffer, 0, buffer.Length); } catch (Exception) { count = 0; } if (count == 0) { Console.WriteLine(name+" closed"); write.Close(); break; } Console.Write(name + ": "+ Encoding.Default.GetString(buffer, 0, count)); write.Write(buffer, 0, count); } } }
通过它获取到的cuteFtp交互命令如下:
connected
remote connected
client->remote: 220 Serv-U FTP Server v6.0 for WinSock ready...
remote->client: USER 1
client->remote: 331 User name okay, need password.
remote->client: PASS 1
client->remote: 230 User logged in, proceed.
remote->client: PWD
client->remote: 257 "/" is current directory.
remote->client: FEAT
client->remote: 211-Extension supported
client->remote: CLNT
MDTM
MDTM YYYYMMDDHHMMSS[+-TZ];filename
SIZE
SITE PSWD;EXEC;SET;INDEX;ZONE;CHMOD;MSG
REST STREAM
XCRC filename;start;end
MODE Z
211 End
remote->client: REST 0
client->remote: 350 Restarting at 0. Send STORE or RETRIEVE.
remote->client: PASV
client->remote: 227 Entering Passive Mode (127,0,0,1,29,18)
remote->client: LIST
client->remote: 150 Opening ASCII mode data connection for /bin/ls.
client->remote: 226 Transfer complete.
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