Avissar Software

IndiFTPD Source Code Notes

Building IndiFTPD - Windows - IndiFTPD can be built for Windows using either "Microsoft Visual Studio .NET 2003" or "Microsoft Visual C++ 6.0". The project files for both Microsoft compilers are located in the indiftpd sub-directory. When using VS .NET indiftpd.sln should be used to open the project. For VC++ 6.0 indiftpd.dsw should be used. To use SSL with IndiFTPD first download the latest OpenSSL source code for version 0.9.6 (available at www.openssl.org). Then build it as described in the OpenSSL documentation. If you already have a build of the libeay32.lib and ssleay32.lib libraries, along with the associated header files, you can skip building OpenSSL. The directions below assume you are building OpenSSL version 0.9.6l with the root directory at the same level as the "ftps" directory. If the libraries and include files are located elsewhere you will need to set the paths accordingly. To enable SSL using "Microsoft Visual Studio .NET 2003" set the following properties for the indiftpd project: > "C/C++ -> General -> Additional Include Directories" add ..\..\openssl-0.9.6l\include > "C/C++ -> Preprocessor -> Preprocessor Definitions" add ENABLE_SSL > "Linker -> General -> Additional Library Directories" add ..\..\openssl-0.9.6l\out32 > "Linker -> Input -> Additional Dependencies" add Gdi32.lib libeay32.lib ssleay32.lib To enable SSL using "Microsoft Visual C++ 6.0" set the following settings for the indiftpd project: > "C/C++ (tab) -> Preprocessor (Category:) -> Additional include directories:" add ..\..\openssl-0.9.6l\include > "C/C++ (tab) -> Preprocessor (Category:) -> Preprocessor definitions:" add ENABLE_SSL > "Link (tab) -> Input (Category:) -> Additional library path:" add ..\..\openssl-0.9.6l\out32 > "Link (tab) -> Input (Category:) -> Object/library modules:" add Gdi32.lib libeay32.lib ssleay32.lib - UNIX - For the UNIX systems (Linux, Solaris, and FreeBSD) the Makefile, also located in the indiftpd sub-directory, should be used. The makefile has one required parameter and one optional parameter. The parameters are passed to the Makefile via environment variables. The required variable, called "platform", must be set to either linux, solaris, or freebsd. The optional parameter, called "opensslroot", must contain the path to the root of the OpenSSL directory tree. Below are two examples of how to use the make command: Example1: make platform=linux Example2: make platform=solaris opensslroot=../../openssl-0.9.6l The library options used in the Makefile may create dependencies on certain shared objects (Ex. libstdc++.so.5). To avoid these dependencies the static libraries should be included instead. For example, the option "-lstdc++" may be replaced with "/usr/lib/gcc-lib/i386-redhat-linux/3.2.2/libstdc++.a" to remove the dependency on the libstdc++.so.5 shared object (library). The path to the libstdc++.a library will vary on different versions of UNIX. Also, using the statically linked libraries will increase the size of the executable. To use SSL download the latest OpenSSL source code for version 0.9.6 (available at www.openssl.org). Then build the code as described in the OpenSSL documentation. Next set the "opensslroot" parameter for the make command to point to the root of the OpenSSL directory tree. If the "opensslroot" parameter is omitted IndiFTPD will be built without SSL support. About the code The IndiFTPD code is partitioned into two primary pieces: the server core, and the specific server implementation. The core contains all the code for a basic FTP server. The only file that must be added to make the core a functional server is an implementation of the main() function. For an example of a minimal implementation of the server core see basicmain.cpp in the "basicftpd" subdirectory. To build BasicFTPD use one of the project files (in Windows) or the Makefile (in UNIX) -- the build process for BasicFTPD is similar to IndiFTPD. IndiFTPD is also designed to be easily extended by simply adding new methods to override the default FTP command implementations. To add new functionality you can simply add methods to the CIndiFtps class. The 2 classes in the core that will most often be overridden are CFtps (in Ftps.cpp/Ftps.h) and CSiteInfo (in SiteInfo.cpp/SiteInfo.h). The CFtps class contains the handlers for all the FTP commands (Ex. LIST, PASV, CWD, etc). It also stores all the state for a client connection. An instance of CFtps is created for each client connection. For an example of how to implement new FTP commands see the CInfiFtps class (in IndiFtps.cpp/ IndiFtps.h). The CSiteInfo class stores all the information for the FTP server. Only 1 instance of the CSiteInfo class should be created in the main() function and passed in to all threads. As a general convention all thread synchronization is contained in the CSiteInfo class. When shared information is needed by a thread, a new copy of the information is returned and never a pointer to the actual shared information. For an example of overriding the CSiteInfo class see the CIndiSiteInfo class (in IndiSiteInfo.cpp/IndiSiteInfo.h). Below is a short description of each core class: CBlowfishCrypt [BlowfishCrypt.cpp/BlowfishCrypt.h]: Implementation of Bruce Schneier's BLOWFISH algorithm from "Applied Cryptography", Second Edition. CCmdLine [CmdLine.cpp/CmdLine.h]: Used to store and manipulate a command line input. This class is used to parse a command line into its individual arguments or recombine an array of arguments into a single string. It can also be used to parse lines in a configuration file. The parse method in CCmdLine can parse a string based on any delimiting character. CCrypto [Crypto.cpp/Crypto.h]: Provides encryption and decryption using the Blowfish algorithm. This class contains methods to encrypt a buffer into a HEX string or decrypt an encrypted HEX string -- used for passwords. CDll [Dll.cpp/Dll.h]: Implements a doubly-linked list. This is used to store information such as the list of users on the site. CFSUtils [FSUtils.cpp/FSUtils.h]: Provides utility functions used for file system access. This class contains methods for directory listing, building and validating paths, getting information about files or directories, deleting and renaming files, getting/setting the current working directory, etc. CFtps [Ftps.cpp/Ftps.h]: Primary class for the FTP server. This class contains all the functions used to handle the FTP commands (Ex. LIST, CWD) as well as storing the current state for each client connection (logged in users). CFtpsXfer [FtpsXfer.cpp/FtpsXfer.h]: This class contains the methods for transferring data. This class is called from the global function ftpsXferThread() that is used to start new threads for FTP data connections. This class is used for data transfer commands such as LIST, RETR, and STOR. CLog [Log.cpp/Log.h]: Basic class for writing to a log file. CService [Service.cpp/Service.h]: This class contains methods to setup an application to run as a service -- not used in IndiFTPD. Currently this is mostly useful for Windows. CSiteInfo [SiteInfo.cpp/SiteInfo.h]: This class is used to store and access information about the server such as configuration information or getting a list of users for the site. Only 1 instance of this class should be created and passed to all the client connection threads. Any information that is shared among the client threads should be accessed through this class. CSock [Sock.cpp/Sock.h]: This class is used to abstract TCP/IP sockets. It contains methods for opening client and server connections, getting the IP address and port of client or server connections, sending and receiving data over the network, setting the options for the connection, etc. CSSLSock [SSLSock.cpp/SSLSock.h]: Implements SSL functionality using the OpenSSL libraries. This class contains methods for generating X509 certificates, public and private keys, negotiating SSL client and server connections, sending and receiving data over SSL, etc. CStrUtils [StrUtils.cpp/StrUtils.h]: Contains string handling methods such as string comparisons, changing the case of a string, matching wildcards, reading a string from the terminal without displaying the typed input, building strings using format options, etc. CTermcli [Termcli.cpp/Termcli.h]: Used to send and receive terminal commands as a client. For example, when sending and receiving commands on the FTP control connection as a client. CTermsrv [Termsrv.cpp/Termsrv.h]: Used to send and receive terminal commands as a server. For example, when sending and receiving commands on the FTP control connection as a server. CThr [Thr.cpp/Thr.h]: Provides threading support. This class contains methods to create and destroy threads along with synchronization functions. CTimer [Timer.cpp/Timer.h]: Provides millisecond accurate timing functions. This class is used to time the duration of events such as data transfers as well as regulate transfer rates. It also contains the sleep method used to block a thread for a specified amount of time.