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General

XDP CPUMap

An update on XDP and CPUMap.

http://vger.kernel.org/netconf2017_files/XDP_devel_update_NetConf2017_Seoul.pdf

Categories
General

Routing and Switching in XDP

https://lkml.org/lkml/2017/10/10/88

https://lkml.org/lkml/2017/10/10/90

Updated patches:

https://lkml.org/lkml/2017/11/4/192

https://lkml.org/lkml/2017/11/4/193

Categories
General

Tracing Packets Through the Kernel

https://blog.yadutaf.fr/2017/07/28/tracing-a-packet-journey-using-linux-tracepoints-perf-ebpf/

Very interesting. The key is that eBPF programs can be attached to tracepoints.

Categories
General

eBPF and XDP Stuff

Worked example of DDOS protection using XDP. It also has this interesting slide:

BPF and XDP Reference Guide

eBPF, part 1: Past, Present, and Future

Categories
General

eBPF Longest Prefix Match Maps

Coming soon to a 4.11 kernel near you, eBPF maps that can do longest prefix matches for things like IP routing.

Awesome.

Categories
General

eBPF Map Size Limits

Recently, I’ve done some work with eBPF and specifically the in-kernel maps that are manipulated and shared by both kernel and user space code.

When doing this I ran into permission errors when installing large maps. It took a little while to figure out that the cause of this was the root user’s locked memory limit being too low (thanks Daniel Borkmann).

The locked memory limit is modified with ulimit:

ulimit -l unlimited