In most network applications, managing incoming flow is an important thing, and is a quite hard thing to set up. In case your algorithm is too restrictive, you will drop too much connection, and in case it’s too permissive, you will accept undesired connections. The real need is to tell your application: « Accept N connection(s) in a X second(s) time range ».
The way you should decide if a connection have to be dropped or not is looking in an historic of X second(s) how many connection(s) from an IP have been performed, and then deducing the count. This is the « simple » algorithm that does that: