今天打算寫一個FtpServer玩一下的，需要看看ftp軟件常用命令形式（完整實現所有ftp命令太麻煩），最開始打算通過抓包看cuteftp是如何訪問ftpserver的，但要把其中的命令保存下來還得一條條復制，太麻煩，便通過proxy模式寫了一個代理程序，來獲取其交互的命令，寫了一個簡單的同步模式下的端口映射程序后，發現比常用的異步proxy要簡單的多，便把這段代碼貼出來，以備日后查詢：

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);
????????}
????}
}

通過它獲取到的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.

轉載于:https://www.cnblogs.com/TianFang/archive/2009/02/02/1382734.html

總結

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