The Link Demo illustrates the basic Liveness and AIT (atomic information transfer) link protocols. It involves direct communication between two server/host machines. AIT can be shown either via command-line tools, or an interactive web page.
The configuration for a basic link demo involves several moving parts.
Major components include:
- An Ethernet connection between machines
- eBPF/XDP programs running in each kernel
- A privileged App Server to access the eBPF Map interface
- A Web Server to handle browser requests
- A client Web Browser to run the interactive visualization(s)
Since there are so many moving parts to the link demo, it's always a good idea to make sure everything is as up-to-date as possible.
$ sudo apt update
$ sudo apt upgrade
$ sudo apt autoremove
$ sudo reboot
(If you need to update your kernel for XDP, see Build Custom Kernel)
$ cd ~/dev/eBPF
$ git pull
$ cd proto
$ make clean all test
$ cd ../XDP
$ make clean all test
$ cd ../http
$ make clean all test
$ sudo make install
Now, follow the Setup instructions to make sure everything is up and running.
Assuming a power-cycle reboot of the machines in the demo configuration, and the software components have already been built, the following steps are required to prepare for the demo:
First, make sure that the eBPF/XDP hook is loaded with the AIT protocol driver.
$ cd ~/dev/eBPF/XDP
$ sudo ip -force link set dev eth0 xdp obj ait_kern.o
Second, start up the AIT application server to provide access to the eBPF Map.
$ cd ~/dev/eBPF/http
$ sudo cgi-fcgi -start -connect /run/ebpf_map.sock ./ebpf_fcgi
$ sudo chown www-data /run/ebpf_map.sock
Finally, open a browser window on the client machine
to display the Link Demo GUI at http://localhost/link_demo.html
(replace localhost with the hostname or IP address of the server).
An HTML page for debugging is available directly from the FastCGI server at
http://localhost/ebpf_map/ait.html