ServU plug-in Design

ServU is a widely used FTP service.Program. It features simplicity, superior performance, stability, and strong scalability. It can better support FTP applications with large concurrent streams and high bandwidth.

ServU supports extension of its functions in the form of plug-ins (C ++ DLL.

I. ServU Workflow

A) default processing process of ServU


1. The client sends a download request

2. The ServU kernel processes the request.

3. Return the processing result (for example, permission judgment)

4. Return the FTP message to the client.

B) operation process when the ins and ServU are combined

1. The client sends a download request

2. The ServU notifies the DLL plug-in the form of an event to process the request.

3A. The DLL plugin captures and processes the event and returns it directly to the ServU service.

3B. The DLL plug-in ignores this event and transfers it to The ServU kernel for processing.

4. The ServU kernel processes the request.

5. Return the FTP message to the client.

Ii. Plug-in configuration

Add the following content to the servudaemon. ini configuration file:

[External] 'plug-in configuration section Clientcheckdll1 = cutesuhook. dll 'client event processing plug-in Eventhookdll1 = cutesuhook. dll 'event processing plug-in

Iii. public interfaces of plug-ins

There are two types of plug-in events: client events and ftpevent events.

Two types of events are triggered by ServU and passed to the plug-in DLL.

The plug-in needs to capture client events and ftpevent events. The C ++ prototype of the capturing function is:

[Export word callback handleeventhook (rftpeventstr * peventstruc ); Export int _ cdecl handleclientevent (rclienteventstr * peventstruc ); # Define export extern "C" _ declspec (dllexport)

Note: You need to export these functions (Export)

RelatedCode: Cutesuhook. Def

[Library cutesuhook Exports Handleeventhook @ 1 Handleclientevent @ 2

Iv. Event Description struct prototype(C # description)

Customer Event Structure

[internal sealed class clientevent {// rclienteventstr structure equivalent to C ++ Public int event ; // event code (4) Public int flag ; // flag. The specific meaning depends on the event (4) Public String User ; // User Name (40) Public String aux ; // auxiliary information (512) Public String hostip ; // server IP address (16) Public uint sessionid ; // unique session ID (4) Public int domainid ; // unique domain ID (4) Public int domainport ; // domain port number (4) };

FTP Event Structure

[Internal sealed class ftpevent {// equivalent to the rftpeventstr structure of C ++ Public uint Event ; // Event code (4) Public uint Subevent ; // Subevent code (4) Public uint Sessionid ; // Unique session ID (4) Public String User ; // User Name (40) Public StringClientip ; // Client IP address (16) Public String Domainip ; // Domain IP (16) Public uint Duration ; // Event cycle, Run Time (4) Public uint Size ; // Object size (for example, file) (4) Public uint Hwindow ; // Send to the window handle (4) Public uint Message ; // Message to be sent (4) Public intptr Preplytext ; // Reply message address (4) Public String Replytext ; // Reply message (this item is not included in the C ++ struct) Public String Auxone ; // Note 1 (512) Public String Auxtwo ; // Note 2 (512) Public int Domainport ; // Domain port number Public uint Domainid ; // Domain ID Public uint Hisize ; // Size information };

V. Event code

Customer Event code table

Internal Enum clienteventcode: int { Connect = 31, // connection event Close = 32, // close the event Secureonly = 40 // whether the user must log on through a secure connection Loginmesfile = 1, // Log On request file Signonmes = 36, // message file for User Login Signoffmes = 37, // The message file before the user exits Password = 3, // verify the User Password Ipaccess = 4, // verify the IP address Writefile = 5, // verify the write permission (Note: only when a new file is created) Readfile = 6, // verify the read permission Modifyfile = 7, // verify the modification permission Listdir = 9, // verify the permission of the running File Changedir = 10, // verify the permission to jump to the specified directory Deletedir = 11, // verify the permission to delete the Directory Createdir = 12, // verify the permission to create a directory Appendfile = 35, // verify the resume permission) Execprog = 8, // verify the permission of the running File Homedir = 2, // return the user's home path Relpaths = 14, // whether to display the relative path relative to the Home Directory Hidehidden = 13, // verify the permission to view the hidden file Alwayslogin = 23, // always Allow Logon Oneloginperip = 24, // whether each IP address allows only one user to log on Logclientip = 25, // whether to record the log of the specified IP Address Speedlimit = 26, // speed limit (bandwidth limit) Maxusers = 29, // maximum number of users (an account) Maxloginperip = 33, // maximum number of logon users per IP Address Timeout = 28, // idle time timeout (unit: minute) Sessiontimeout = 39 // set the user's timeout time (unit: minute) }

Note 1: Common events

Connect,Ipaccess,Password,Loginmsgfile,Homedir

NOTE 2: event occurrence Sequence

Connect->Ipaccess(X)->Password->Password->Ipaccess->Event. Login->Event. Close

Note 1: Common events

Login,Close,Hookcommand,Hookreply,Abortdown,Progdown,Enddown,Hookdown

NOTE 2: event occurrence Sequence

Login->Hookcommand/Hookreply/Hookdown->Progdown->Abortdown/Enddown

FTP event encoding table

Internal Enum ftpeventcode: int { Connect = 2, // when the client connects to the server Close = 3, // occurs before the client is disconnected Login = 8, // when the customer successfully logs on Startup = 9, // when the upload starts Abortup = 13, // when the upload is terminated Progup = 20, // This event will occur continuously during the upload Process Endup = 10, // when the upload is successful Startdown = 11, // The download starts. Abortdown = 14, // when the download ends Progdown = 21, // This event will occur continuously during the download process Enddown = 12, // when the download is successful Chgdir = 18, // This occurs when the user changes the directory. Hookdown = 100, // triggered when the client needs to be downloaded Hookup = 101, // triggered when the client needs to upload Hooksite = 108, // triggered when the site XXX command is executed Hookchgdir = 109, // occurs when the client changes the current directory Hookcommand = 110, // triggered when the client issues a command Hookreply = 111 // FTP reply message will trigger this event }