Leveraging eBPF for programmable network functions with IPv6 Segment Routing

TL;DR

This paper demonstrates how eBPF in Linux can be used to implement flexible, programmable network functions within IPv6 Segment Routing, supporting SDN, NFV, and SFC with acceptable performance overhead.

Contribution

It introduces a Linux kernel extension using eBPF for in-network programmability with IPv6 Segment Routing, enabling custom network functions.

Findings

eBPF functions can be integrated with IPv6 Segment Routing in Linux.

The implementation supports diverse network functions like delay measurement and network discovery.

Performance overhead of eBPF functions is acceptable for practical use.

Abstract

With the advent of Software Defined Networks (SDN), Network Function Virtualisation (NFV) or Service Function Chaining (SFC), operators expect networks to support flexible services beyond the mere forwarding of packets. The network programmability framework which is being developed within the IETF by leveraging IPv6 Segment Routing enables the realisation of in-network functions. In this paper, we demonstrate that this vision of in-network programmability can be realised. By leveraging the eBPF support in the Linux kernel, we implement a flexible framework that allows network operators to encode their own network functions as eBPF code that is automatically executed while processing specific packets. Our lab measurements indicate that the overhead of calling such eBPF functions remains acceptable. Thanks to eBPF, operators can implement a variety of network functions. We describe the architecture of our implementation in the Linux kernel. This extension has been released with Linux 4.18. We illustrate the flexibility of our approach with three different use cases: delay measurements, hybrid networks and network discovery. Our lab measurements also indicate that the performance penalty of running eBPF network functions on Linux routers does not incur a significant overhead.