- A full description of this example can be found in Chapter 7. It contains shows how to use this program against a webserver and has a full explanation of the arguments used. Please refer to the book.
- Please remember that the examples here are tested in the Vagrant machine. Please read more in README.md.
- Make sure to change the example accordingly if you wish to build somewhere else, open an issue if you have problems doing so!
- All the dependencies are already handled if you followed the instructions in the main README.md.
VERY VERY VERY IMPORTANT NOTE ON LOCKING YOURSELF OUT OF THE MACHINE: The code in this example basically filters all the TCP packets to a given network interface. If you are connected via SSH to this machine, make sure to use another interface or change the program accordingly. The Vagrant environment already does this if you need a quick win!
In the machine:
Enter into this example folder:
cd ~/linux-observability-with-bpf/code/chapter-7/iproute2You can now use the compile.sh script to create the program.o ELF file.
Now that you have it, you can load the program to an interface. We will use eth1 again because the program
blocks TCP packets and we are connected to the Vagrant machine trough SSH :)
sudo ip link set dev eth1 xdp obj program.o sec mysectionPlease note that you can see that the program was loaded by doing an ip a and looking for xdpgeneric in the eth network interface.
To unload the program you have to do:
sudo ip link set dev eth1 xdp off