SNAP: Stateful Network-Wide Abstractions for Packet Processing

Early programming languages for software-defined networking (SDN) were built on top of the simple match-action paradigm offered by OpenFlow 1.0. However, emerging hardware and software switches offer much more sophisticated support for persistent state in the data plane, without involving a central controller. Nevertheless, managing stateful, distributed systems efficiently and correctly is known to be one of the most challenging programming problems. To simplify this new SDN problem, we introduce SNAP. SNAP offers a simpler "centralized" stateful programming model, by allowing programmers to develop programs on top of one big switch rather than many. These programs may contain reads and writes to global, persistent arrays, and as a result, programmers can implement a broad range of applications, from stateful firewalls to fine-grained traffic monitoring. The SNAP compiler relieves programmers of having to worry about how to distribute, place, and optimize access to these stateful arrays by doing it all for them. More specifically, the compiler discovers read/write dependencies between arrays and translates one-big-switch programs into an efficient internal representation based on a novel variant of binary decision diagrams. This internal representation is used to construct a mixed-integer linear program, which jointly optimizes the placement of state and the routing of traffic across the underlying physical topology. We have implemented a prototype compiler and applied it to about 20 SNAP programs over various topologies to demonstrate our techniques' scalability

Experience with abstract notation one

The development of computer science has produced a vast number of machine architectures, programming languages, and compiler technologies. The cross product of these three characteristics defines the spectrum of previous and present data representation methodologies. With regard to computer networks, the uniqueness of these methodologies presents an obstacle when disparate host environments are to be interconnected. Interoperability within a heterogeneous network relies upon the establishment of data representation commonality. The International Standards Organization (ISO) is currently developing the abstract syntax notation one standard (ASN.1) and the basic encoding rules standard (BER) that collectively address this problem. When used within the presentation layer of the open systems interconnection reference model, these two standards provide the data representation commonality required to facilitate interoperability. The details of a compiler that was built to automate the use of ASN.1 and BER are described. From this experience, insights into both standards are given and potential problems relating to this development effort are discussed

The TASTE Toolset: turning human designed heterogeneous systems into computer built homogeneous software.

The TASTE tool-set results from spin-off studies of the ASSERT project, which started in 2004 with the objective to propose innovative and pragmatic solutions to develop real-time software. One of the primary targets was satellite flight software, but it appeared quickly that their characteristics were shared among various embedded systems. The solutions that we developed now comprise a process and several tools ; the development process is based on the idea that real-time, embedded systems are heterogeneous by nature and that a unique UML-like language was not helping neither their construction, nor their validation. Rather than inventing yet another "ultimate" language, TASTE makes the link between existing and mature technologies such as Simulink, SDL, ASN.1, C, Ada, and generates complete, homogeneous software-based systems that one can straightforwardly download and execute on a physical target. Our current prototype is moving toward a marketed product, and sequel studies are already in place to support, among others, FPGA systems

An implementation and analysis of the Abstract Syntax Notation One and the basic encoding rules

The details of abstract syntax notation one standard (ASN.1) and the basic encoding rules standard (BER) that collectively solve the problem of data transfer across incompatible host environments are presented, and a compiler that was built to automate their use is described. Experiences with this compiler are also discussed which provide a quantitative analysis of the performance costs associated with the application of these standards. An evaluation is offered as to how well suited ASN.1 and BER are in solving the common data representation problem

Everything counts in small amounts

This paper describes an encoding tool which utilises the "data is code" principle of symbolic expressions available in Lisp-like languages to allow the scripting of tightly packed, cross-platform network protocols. This dynamic approach provides specific flexibility when working on embedded systems as it reduces the amount of cross compilation and deploy cycles that occur following more traditional development approaches. In addition, the separation of how the data is encoded from the compiled application facilitates a concept known as extensibility of the network protocol without requiring special handling

A Data Transformation System for Biological Data Sources

Scientific data of importance to biologists in the Human Genome Project resides not only in conventional databases, but in structured files maintained in a number of different formats (e.g. ASN.1 and ACE) as well a.s sequence analysis packages (e.g. BLAST and FASTA). These formats and packages contain a number of data types not found in conventional databases, such as lists and variants, and may be deeply nested. We present in this paper techniques for querying and transforming such data, and illustrate their use in a prototype system developed in conjunction with the Human Genome Center for Chromosome 22. We also describe optimizations performed by the system, a crucial issue for bulk data

Seedemu: The Seed Internet Emulator

I studied and experimented with the idea of building an emulator for the Internet. While there are various already available options for such a task, none of them takes the emulation of the entire Internet as an important feature in mind. Those emulators and simulators can handle small-scale networks pretty well, but lacks the ability to handle large-size networks, mainly due to: - Not being able to run many nodes, or requires very powerful hardware to do so,- Lacks convenient ways to build a large emulation, and - Lacks reusability: once something is built, it is very hard to re-use them in another emulation I explored, in the context of for-education Internet emulators, different ways to overcome the above limitations. I came up with a framework that enables one to create emulation using code. The framework provides basic components of the Internet. Some examples include routers, servers, networks, Internet exchanges, autonomous systems, and DNS infrastructure. Building emulation with code means it is easy to build emulation with complex topologies since one can make use of the common control structures like loops, subroutines, and functions. The framework exploits the idea of ``layers.\u27\u27 The idea of ``\emph{layers}\u27\u27 can be seen as an analogy of the idea of ``layers\u27\u27 in image processing software, in the sense that each layer contains parts of the image (in this case, part of the emulation), and need to be ``rendered\u27\u27 to obtain the resulting image. There are two types of layers, base layers and service layers. Base layers describe the ``base\u27\u27 of the topologies, like how routers, servers, and networks are connected, how autonomous systems are peered with each other; service layers describe the high-level services on the Internet. Examples of services layers are web servers, DNS servers, ethereum nodes, and botnet nodes. No layers are tied to any other layers, meaning each layer can be individually manipulated, exported, and re-used in another emulation. One can build an entire DNS infrastructure, complete with root DNS, TLD DNS, and deploy it on any base layer, even with vastly different underlying topologies. The result of the rendered layer is a set of data structures that represents the objects in a network emulation, like host, router, and networks. These representations can then be ``compiled\u27\u27 into something that one can execute using a compiler. The main target platform of the framework is Docker. The source of the SEEDEMU project is publicly available on Github: https://github.com/seed-labs/seed-emulator

Eliminating Network Protocol Vulnerabilities Through Abstraction and Systems Language Design

Incorrect implementations of network protocol message specifications affect the stability, security, and cost of network system development. Most implementation defects fall into one of three categories of well defined message constraints. However, the general process of constructing network protocol stacks and systems does not capture these categorical con- straints. We introduce a systems programming language with new abstractions that capture these constraints. Safe and efficient implementations of standard message handling operations are synthesized by our compiler, and whole-program analysis is used to ensure constraints are never violated. We present language examples using the OpenFlow protocol