A Caching SFC Proxy Based on eBPF
Marco Haeberle, Benjamin Steinert, Michael A. Weiss, Michael Menth · 2022
Service Functions (SFs) are intermediate processing nodes on the path of IP packets. With SF chaining (SFC), packets can be steered to multiple physical or virtual SFs in a specific order. SFC-unaware SFs can be used flexibly but they do not support SFC-specific encapsulation of packets. Therefore, an SFC proxy needs to remove the encapsulation of a packet before processing by an SFC-unaware SF, and to add it again afterwards. Such an SFC proxy typically runs on a server hosting virtual network functions (VNFs) that serve as SFs. Simple SFC proxies adapt a flow-specific static header stack. That is, each VNF requires an own SFC proxy, and the proxy cannot be extended to support per-packet metadata in the SFC encapsulation. The caching SFC proxy presented in this work caches packet-specific headers while packets are processed by a VNF, i.e., packet-specific header information is preserved. We present concept, use cases, and an eBPF-based implementation of the caching SFC proxy. In addition, we evaluate the performance of a prototype.