eBPF Load balancer

Linux eBPF load balancer to be attached into SO_REUSEPORT socket group.

This eBPF program allows load balance packets based on their src IP. All packets from the same src IP will land into the same collector.

Dependencies

This project uses autotools, gcc and clang to compile.

On Ubuntu:

$ sudo apt install autoconf libtool make automake gcc pkg-config

On Centos (tested on Centos 8):

$ sudo yum install autoconf libtool make automake pkgconf

eBPF Dependencies

To use eBPF loadbalancing Python3 is needed for eBPF compilation. Another requirement is libbpf (github.com/libbpf/libbpf) >= 0.4.0.

On Ubuntu:

$ sudo apt install clang libbpf-dev linux-tools-$(uname -r)

On Centos (tested on Centos 8):

$ sudo yum install clang
$ sudo dnf --enablerepo=powertools install libbpf-devel
$ sudo dnf install bpftool

Install

To install src code:

$ ./bootstrap
$ ./configure       # See ./configure --help for options
$ make
$ make install      # Usually needs sudo permissions

Configure options

There are some custom ./configure options :

• --with-pkgconfigdir=[/own_path/pkgconfig]: overwrite pkgconfig directory to install .pc file [default: ${PREFIX}/lib/pkgconfig]
• --with-linux=[/own_path/linux/src]: linux source code necesary for eBPF compilation [default: /usr/src/linux]. (On Ubuntu use /usr/src/-generic version)
• --enable-debug: enable logs in both user-space and kernel-space eBPF program.

Usage

See main example. This example initializes an UDP socket bound to an address/port and attaches the eBPF load balancer to the socket.

There is a udp_publisher to test the collector.

Running

To test the loadbalancer, multiple instances should be launched. In this example, messages will be loadbalanced to 3 instances based on their src IP.

To run 3 collectors:

$ cd src
$ sudo bash -c 'ulimit -l unlimited; ./main 10.0.2.15 10001 0 3'   // first collector
$ sudo bash -c 'ulimit -l unlimited; ./main 10.0.2.15 10001 1 3'   // second collector
$ sudo bash -c 'ulimit -l unlimited; ./main 10.0.2.15 10001 2 3'   // third collector

To see the loadbalancer working, you should instance multiple publishers sending from different src ips, otherwise, all packets will be hashed to the same collector.

Publisher:

$ cd src
$ ./udp_publisher 10.0.2.15 10001 100

Debug

To show the maps:

(sudo may be needed)

$ bpftool map dump name tcp_balancing_t
$ bpftool map dump name udp_balancing_t

Logs in eBPF program can be activated using the flag --enable-debug of autotools. Logs for eBPF program are in /sys/kernel/debug/tracing/trace

Credits

This repository is based on reuseport, a loadbalancer used in pmacct.