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Checking-in on Network Functions
by Zeeshan Lakhani and Heather Miller
The rise of network functions?
Checking-in on Network Functions 2 Lakhani/Miller
Checking-in on Network Functions by Zeeshan Lakhani and Heather - - PowerPoint PPT Presentation
Checking-in on Network Functions by Zeeshan Lakhani and Heather - - PowerPoint PPT Presentation
Checking-in on Network Functions by Zeeshan Lakhani and Heather Miller @ The rise of network functions? Lakhani/Miller Checking-in on Network Functions 2 The rise of network functions? LB Firewall IDS Lakhani/Miller Checking-in on
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The rise of network functions?
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∨ Firewall IDS LB
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The rise of network functions?
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∨ Firewall IDS LB
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The rise of network functions?
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∨ Firewall IDS LB
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The rise of network functions?
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writing and modeling
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Pyretic Slick NetKat
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The rise of network functions?
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writing and modeling
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Writing network functions is not “composed of nothing more than algorithms and small programs”[1] complex routing and load balancing policies traffic monitoring experimental/new specifications, protocols, and headers computation and aggregation (e.g. In-Network Computation is a Dumb Idea Whose Time Has Come)
[1] Cultures of programming: Understanding the history of programming through controversies and technical artifacts by Tomas Petricek, University of Kent, UK, 2019
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Motivation
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Motivation
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If I program in React, can I program a network function?
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Motivation
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If I program in React, can I program a network function?
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How do we know what we’re doing is right?
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Motivation
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If I program in React, can I program a network function?
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How do we know what we’re doing is right? How can we iterate?
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Motivation
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Limits of Correctness e.g. reliance on OpenFlow protocol
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Motivation
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Limits of Correctness e.g. reliance on OpenFlow protocol Arbitrary (ad-hoc) Logic & Variable-length Data, e.g. Ipv6 Extensions, ndp options packet length failure and reconfiguration
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Motivation
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[2]
[2] The Click Modular Router by Eddie Kohler, et. al., Laboratory for Computer Science, MIT, 1999
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Two examples
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MTU: Send Too Big
swap ethernet addresses swap src/dst change protocol set mtu info calculate checksum
Ipv6 Extension Headers: SRH
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Two examples
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MTU: Send Too Big
swap ethernet addresses swap src/dst change protocol set mtu info calculate checksum
Ipv6 Extension Headers: SRH
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Kinds of Contracts
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Kinds of Contracts
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focused on how runtime contracts can be turned on for monitoring and testing situations so that developers can “sit back, and just watch their contracts be violated” erased on release binaries Design by Contract
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Kinds of Contracts
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focused on how runtime contracts can be turned on for monitoring and testing situations so that developers can “sit back, and just watch their contracts be violated” erased on release binaries Design by Contract Static Assertions compile-time assertions for consts, statics remain in release binaries
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Kinds of Contracts
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focused on how runtime contracts can be turned on for monitoring and testing situations so that developers can “sit back, and just watch their contracts be violated” erased on release binaries Design by Contract Static Assertions compile-time assertions for consts, statics remain in release binaries
Static Order- Preserving Headers
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Kinds of Contracts: Design by Contract
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Kinds of Contracts: Design by Contract
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Kinds of Contracts: Design by Contract
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Kinds of Contracts: Static Assertions
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Kinds of Contracts: Static Assertions
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Kinds of Contracts: Static Assertions
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Kinds of Contracts: Static Order-Persevering Headers
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Kinds of Contracts: Static Order-Persevering Headers
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Implementation
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Implementation
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prototyped as a gradual extension to NetBricks (i.e. NetBricks: Taking the V out of NFV, OSDI 2016)
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Implementation
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prototyped as a gradual extension to NetBricks (i.e. NetBricks: Taking the V out of NFV, OSDI 2016)
Focused on Zero-Copy Sofu Isolation
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Implementation
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prototyped as a gradual extension to NetBricks (i.e. NetBricks: Taking the V out of NFV, OSDI 2016) implemented as a small rust library to easily write specifications, which generates code for validations and assertions at compile-time
Focused on Zero-Copy Sofu Isolation
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Implementation
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prototyped as a gradual extension to NetBricks (i.e. NetBricks: Taking the V out of NFV, OSDI 2016) implemented as a small rust library to easily write specifications, which generates code for validations and assertions at compile-time
Focused on Zero-Copy Sofu Isolation macros turn checks into static and dynamic contracts
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Implementation
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In Action
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In Action
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- rder is checked
statically via a trace of packet contents
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In Action
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- rder is checked
statically via a trace of packet contents pre-checks validate incoming contents and store contents @ runtime
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In Action
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- rder is checked
statically via a trace of packet contents pre-checks validate incoming contents and store contents @ runtime post-checks validate transformed contents against pre-check contents
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Evaluation
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Evaluation
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Design Phase
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Evaluation: Syntax Added
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Evaluation: Compilation Time
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Evaluation: Runtime Cost
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Due to: mirroring and tracing packet contents runtime checks storage overhead
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Evaluation: Runtime Cost
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Due to: mirroring and tracing packet contents runtime checks storage overhead
Design Phase
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Future Work
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deployment models / running contracts in simulation / CI e.g. via Mininet / Containernet (further) leverage static analysis of input programs interactive feedback (many examples in UI tooling and langs like Elm and Rust) program slicing refinement via domain-specific heuristics and constraint solving
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In Practice
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Scoped Side Effects cascade packet length checksum etc… Typed Packets
Header : TCP Envelope : T < T : IpPacket >
λ → λ
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Takeaways
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we need betuer approaches to VERIFY and INTERACT with network functions and packet processing program properties here, we provide a HYBRID-APPROACH and implementation for GRADUALLY checking and validating the arbitrary logic and side effects by COMBINING design by contract, static assertions and type-checking, and code generation via macros all without PENALIZING programmers at development time