Feature/bind source ip

[hishamanver]

Includes changes from #22

What

• bind to local_ip and port when running in client mode (already done for server mode)
• if local port is not explicitly set, then a random free port will be assigned
• unit tests updated with new test cases

Why

When sending the INIT sctp message, we can see the following when executing the container on a Virtual Machine which has multiple interfaces

We have a usecase where we are attempting to run a diameter client from within a kubernetes cluster. The worker nodees have a large list of IP addresses associated with them. As a result the INIT message advertises all the ip addresses and the packet becomes too large leading to fragmentation

Before

After

reasonable size packet
(no ip address as this is not multihomed - https://www.rfc-editor.org/rfc/rfc9260.html#name-initiation-init-1)

Verification

$ python3 -m unittest tests/*.py
...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................
----------------------------------------------------------------------
Ran 483 tests in 84.340s

OK