A two-day Networking Track will be featured at this year’s Linux Plumbers Conference; it will run the first two days of LPC, November 13-14. The track will consist of a series of talks, including a keynote from David S. Miller: “This talk is not about XDP: From Resource Limits to SKB Lists”.
Official Networking Track website: http://vger.kernel.org/lpc-networking2018.html
XDP already offers rich facilities for high performance packet
processing, and has seen deployment in several production systems.
However, this does not mean that XDP is a finished system; on the
contrary, improvements are being added in every release of Linux, and
rough edges are constantly being filed down. The purpose of this talk is
to discuss some of these possibilities for future...
XDP is a framework for running BPF programs in the NIC driver to allow
decisions about the fate of a received packet at the earliest point in
the Linux networking stack. For the most part the BPF programs rely on
maps to drive packet decisions, maps that are managed for example by a
userspace agent. This architecture has implications on how the system is
configured, monitored and debugged.
Over the past several years, BPF has steadily become more powerful in multiple
ways: Through building more intelligence into the verifier which allows more
complex programs to be loaded, and through extension of the API such as by
adding new map types and new native BPF function calls. While BPF has its roots
in applying filters at the socket layer, the ability to introspect the...
In this talk we describe our experiences in evaluating DC-TCP. Preliminary testing with Netesto uncovered issues with our NIC that affected fairness between flows, as well as bugs in the DC-TCP code path in Linux that resulted in RPC tail latencies of up to 200ms. Once we fixed those issues, we proceeded to test in a 6 rack mini cluster running some of our production applications. This testing...
Linux bridge is deployed on Hosts, Hypervisors, Container OS's and in most recent years on data center switches. It is complete in its feature set with forwarding, learning, proxy and snooping functions. It can bridge Layer-2 domains between VM's, Containers, Racks, POD's and between data centers as seen with Ethernet-Virtual Private networks [1, 2]. With Linux bridge deployments moving up the...
The eXpress Data Path (XDP) is a new kernel-feature, intended to provide
fast packet processing as close as possible to device hardware. XDP
builds on top of the extended Berkely Packet Filter (eBPF) and allows
users to write a C-like packet processing program, which can be attached
to the device driver’s receiving queue. When the device observes an
incoming packet, the user-defined XDP...
Port mirroring is one of the most common network troubleshooting
techniques. SPAN (Switch Port Analyzer) allows a user to send a copy
of the monitored traffic to a local or remote device using a sniffer
or packet analyzer. RSPAN is similar, but sends and received traffic
on a VLAN. ERSPAN extends the port mirroring capability from Layer 2
to Layer 3, allowing the mirrored traffic to be...
AF_XDP is a new socket type for raw frames to be introduced in 4.18
(in linux-next at the time of writing). The current code base offers
throughput numbers north of 20 Mpps per application core for 64-byte
packets on our system, however there are a lot of optimizations that
could be performed in order to increase this even further. The focus
of this paper is the performance optimizations we...
iptables have been the typical tool to create firewall for linux hosts. We have used them at Facebook for setting up host firewalls on our servers across a variety of tiers. In this proposal, we introduce a eBPF / XDP based firewall solution which we use for packet filtering and has parity to our iptables implementation. We discuss various aspects of this. Following is a brief summary of...
This talk is a continuation of the initial XDP HW-based hints work presented at NetDev 2.1 in Seoul, South Korea.
It will start with focus on showcasing new prototypes to allow an XDP program to request required HW-generated metadata hints from a NIC. The talk will show how the hints are generated by the NIC and what are the performance characteristics for various XDP applications. We also...
SCTP is a transport protocol, like TCP and UDP, originating from SIGTRAN
IETF Working Group in the early 2000's with the initial objective of
supporting the transport of PSTN signalling over IP networks. It featured
multi-homing and multi-stream from the beginning, and since then there
have been a number of improvements that help it serve other purposes too,
such as support for Partial...
phylib has provided the API Ethernet MAC drivers have used to control
Copper PHYs for many years. However with the advent of MACs/PHYs with
bandwidth of > 1Gbps, SERDES interfaces and fibre optical modules,
phylib is not sufficient. phylink provides an API which MAC drivers
can use to control these more complex and dynamic, possibly
hot-pluggable PHYs. This presentation will explain why...
This talk is divided into two parts, first we present on kTLS, the current kernel's
sockmap BPF architecture for L7 policy enforcement, as well as the kernel's ULP and
strparser framework which is utilized by both in order to hook into socket callbacks
and determine message boundaries for subsequent processing.
We further elaborate on the challenges we face when trying to combine kTLS with...
UDP is a popular foundation for new protocols. It is available across
operating systems without superuser privileges and widely supported
by middleboxes. Shipping protocols in userspace on top of
a robust UDP stack allows for rapid deployment, experimentation
and innovation of network protocols.
But implementing protocols in userspace has limitations. The
environment lacks access to features...
Among the various ways of using eBPF, OVS has been exploring the power
of eBPF in three: (1) attaching eBPF to TC, (2) offloading a subset of
processing to XDP, and (3) by-passing the kernel using AF_XDP.
Unfortunately, as of today, none of the three approaches satisfies the
requirements of OVS. In this presentation, we’d like to share the
challenges we faced, experience learned, and seek for...
Over the last 10 years the world has seen NICs go from single port,
single netdev devices, to multi-port, hardware switching, CPU/NFP
having, FPGA carrying, hundreds of attached netdev providing,
behemoths. This presentation will begin with an overview of the
current state of filtering and scheduling, and the evolution of the
kernel and networking hardware interfaces. (HINT: it’s a bit of...
Today every packet which is reaching Facebook’s network is being processed by XDP enabled application. We have been using it for more then 1.5 years and this talk is about evolution of XDP and BPF which has been driven by our production needs. I’m going to talk about history of changes in core BPF components as well as will show why and how it was done. What performance improvements did we get...
Currently the Linux kernel implements two distinct datapaths for Open
vSwitch: the ovskdp and the TC DP. The latter has been added recently
mainly to allow HW offload, while the former is usually preferred for
SW based forwarding due to functional and performance reasons.
We evaluate both datapaths in a typical forwarding scenario - the PVP
test - using the perf tool to identify bottlenecks...
eBPF (extended Berkeley Packet Filter) has been shown to be a flexible
kernel construct used for a variety of use cases, such as load balancing,
intrusion detection systems (IDS), tracing and many others. One such
emerging use case revolves around the proposal made by William Tu for
the use of eBPF as a data path for Open vSwitch. However, there are
broader switching use cases developing...
Linux currently provides mechanisms for managing and allocating many of the system resources such as CPU, Memory, etc. Network resource management is more complicated since networking deals not only with a local resource, such as CPU management does, but can also deal with a global resource. The goal is not only to provide a mechanism for allocating the local network resource (NIC bandwidth),...