Research On Telnet And FTP Protocol In A Localized Operating System

With the development of modern computer science and technology,a global information society is rapidly forming.At the same time,the major impact of information security on national economic development and social stability is becoming increasingly prominent.The development of independent and controllable localized operating system technology is urgent.The current mainstream embedded operating systems in our country are mostly imported from abroad.Security issues become the top priority,especially when it comes to important fields such as national military and aerospace.We must always be alert that external attackers will use the technical vulnerabilities to bypass the system’s safe operation mechanism and obtain user privacy and data,including operating system privilege escalation or backdoor programs,etc.Therefore,our country has continuously increased the importance and protection of localized operating systems with independent intellectual property rights.This project combines the research and development process of a network protocol stack in a domestic operating system.It studies the remote login and file transfer module of the protocol stack,which mainly focuses on the design and application of the Telnet protocol and the FTP protocol in the domestic embedded operating system.Firstly,research and analyze the application layer protocol of a domestic operating system and the function call interface of the Socket module.Combining the SOCKET virtualization technology,insert the BSD4.4 Socket between the application layer and the transport layer of the existing network model called TCP/IP.Telnet protocol and FTP protocol are completed to directly connect with BSD4.4 Socket.Secondly,in the Telnet protocol,the server can generate multiple threads at the same time.The client optimizes the finite state machine based on the Linux system and designs a new state machine that simplifies the negotiation of options,which pass the test and apply to the domestic operating system successfully.The error automatic debugging function is designed in the FTP protocol,and the data sending function and receiving function are optimized to improve the transmission rate.Finally,realize the BSD4.4 Socket interface of the domestic platform.Adopt the method of stripping application files.The written Telnet protocol and FTP protocol source code are combined with the BSD4.4 Socket protocol to realize the transplantation of a domestic embedded operating system.After the test part runs in the Linux environment successfully,it is transplanted to a localized system environment in a certain aerospace field for testing and passing.The remote login and file transfer based on the domestic operating system,which is researched and implemented in the thesis,meets the design requirement and achieves the expected goal.The system implements the built-in Telnet protocol and FTP protocol,which provides more complete functions for the localized platform,which has the characteristics of low power consumption and high security,etc.The most important thing is the independent and controllable purpose that can be achieved.