Firewall with OpenFlow

For the firewall function demonstration, we will use the existing ryu/app/rest_firewall.py application and combine the knowledge we gained in this chapter about the REST API and flow modification. This is a simplified version of the Ryu book firewall example, https://osrg.github.io/ryu-book/en/html/rest_firewall.html. Besides firewall operations, the Ryu firewall example in the link provided illustrates the usage of multi-tenancy with VLAN. The example covered in this section will focus on the correlation between the firewall application and OpenFlow for learning purposes. This section and the linked example would be good complements of each other. If you take a look at the rest_firewall.py code, you will notice a lot of similarities with ofctl_rest.py. In fact, most of the rest_* applications have similar functions when it comes to callback functions and URL dispatch. This is great news for us, since we only have to learn the pattern once and can apply it to multiple...