Leveraging eBPF for programmable network functions with IPv6 segment routing

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.

A Theoretical Framework for Network Monitoring Exploiting Segment Routing Counters

“…The feature of SR of keeping flow state information only at the head end node of a policy, is a crucial aspect for the reliability of the proposed delay measurement tool. In [28], eBPF is exploited as a method to add programmability to the data plane, i.e., to define programs and routines to be applied on incoming packets. In particular, a new type of function SID is defined, named END.BPF, which allows to the source node to ask to a given network node to apply a eBPF program on a packet.…”

Beyond socket options: making the linux TCP stack truly extensible

“…Several networking use cases already leverage eBPF. For example, XDP uses it for fast packet processing [37], IPv6 Segment Routing uses it to support network programming [67] and it improves the extensibility of Open vSwitch [61]. A key benefit of the in-kernel eBPF virtual machine is that each eBPF bytecode is provably verified before being injected inside the kernel.…”

Cadeia-Aberta: Arquitetura para SFC em Kernel Usando eBPF

“…Os autores também adicionaram o mecanismo da biblioteca libpcap a um switch OpenFlow para executar esse bytecode [Jouet et al 2015]. Xhonneaux et al [Xhonneux et al 2018] também utiliza programas eBPF para habilitar a arquitetura de SFC utilizando roteamento por segmento, discutido anteriormente. No contexto de segurança, Betrone et al propõem uma nova ferramenta iptables baseada em eBPF.…”