Content based packet filtering in linux kernel using deterministic finite automata

Bilal, Tahir
In this thesis, we present a content based packet filtering Architecture in Linux using Deterministic Finite Automata and iptables framework. New generation firewalls and intrusion detection systems not only filter or inspect network packets according to their header fields but also take into account the content of payload. These systems use a set of signatures in the form of regular expressions or plain strings to scan network packets. This scanning phase is a CPU intensive task which may degrade network performance. Currently, the Linux kernel firewall scans network packets separately for each signature in the signature set provided by the user. This approach constitutes a considerable bottleneck to network performance. We implement a content based packet filtering architecture and a multiple string matching extension for the Linux kernel firewall that matches all signatures at once, and show that we are able to filter network traffic by consuming constant bandwidth regardless of the number of signatures. Furthermore, we show that we can do packet filtering in multi-gigabit rates.


Dosso - automatic detector of shared objects in multithreaded java programs
Tolubaeva, Munara; Betin Can, Aysu; Department of Information Systems (2009)
In this thesis, we present a simple and efficient automated analysis tool called DoSSO that detects shared objects in multithreaded Java programs. DoSSO reports only the shared objects that are modified by at least one thread. Based on this tool, we propose a new approach in developing concurrent software where programmers implement the system without considering synchronization issues first and then use appropriate locking mechanism only for the objects reported by DoSSO. To evaluate the applicability of D...
Data sharing and access with a corba data distribution service implementation
Dursun, Mustafa; Bilgen, Semih; Department of Electrical and Electronics Engineering (2006)
Data Distribution Service (DDS) specification defines an API for Data-Centric Publish-Subscribe (DCPS) model to achieve efficient data distribution in distributed computing environments. Lack of definition of interoperability architecture in DDS specification obstructs data distribution between different and heterogeneous DDS implementations. In this thesis, DDS is implemented as a CORBA service to achieve interoperability and a QoS policy is proposed for faster data distribution with CORBA features.
Implementation of concurrent constraint transaction logic and its user interface
Altunyuva, Fethi; Karagöz, Pınar; Department of Computer Engineering (2006)
This thesis implements a logical formalism framework called Concurrent Constraint Transaction Logic (abbr.,CCTR) which was defined for modeling and scheduling of workflows under resource allocation and cost constraints and develops an extensible and flexible graphical user interface for the framework. CCTR extends Concurrent Transaction Logic and integrates with Constraint Logic Programming to find the correct scheduling of tasks that involves resource and cost constraints. The developed system, which integ...
Ontology-based spatio-temporal video management system
Şimşek, Atakan; Çiçekli, Fehime Nihan; Department of Computer Engineering (2009)
In this thesis, a system, called Ontology-Based Spatio-Temporal Video Management System (OntoVMS) is developed in order to supply a framework which can be used for semantic data modeling and querying in video files. OntoVMS supports semantic data modeling which can be divided into concept modeling, spatio-temporal relation and trajectory data modeling. The system uses Rhizomik MPEG-7 Ontology as the core ontology. Moreover ontology expression capability is extended by automatically attaching domain ontologi...
Design and implementation of a plug-in framework for distributed object technologies
Kadıoğlu, Koray; Doğru, Ali Hikmet; Department of Computer Engineering (2006)
This thesis presents a framework design and implementation that enables run-time selection of different remote call mechanisms. In order to implement an extendable and modular system with run-time upgrading facility, a plug-in framework design is used. Since such a design requires enhanced usage of run-time facilities of the programming language that is used to implement the framework, in this study Java is selected because of its reflection and dynamic class loading facilities. A sample usage of this frame...
Citation Formats
T. Bilal, “Content based packet filtering in linux kernel using deterministic finite automata,” M.S. - Master of Science, Middle East Technical University, 2011.