Move get_ip_address_if() to NetworkStack and include it in multihoming test

[michalpasztamobica]

Summary of changes

When working on multihoming feature, get_ip_address_if() was wrongly put into OnboardNetworkStack::Interface. This is incorrect, because every of those interfaces only knows its own address, so it could only return and empty address in case the name doesn't match its name or it actual address if it does. Further more, the OnboardNetworkStack::Interface::get_ip_address_if() was not internally connected to any public API.

Instead get_ip_address_if() should only be an API of NetworkStack and implemented in LWIP class. This way we can make best use of the feature: the stack holding multiple interfaces will find the one with a matching name and return its address.

We haven't noticed this, because, the function was never called in our greentea tests. I don't think it deserves its own dedicated test, but at least I added checks confirming that the API returns the same addresses that the eth/wifi interfaces do, based on their string name identifiers.

Impact of changes

No real impact - the NetworkStack::get_ip_address_if() function will become usable.

Migration actions required

None.

Documentation

Already in place

---

Pull request type

[x] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[] Feature update (New feature / Functionality change / New API)
[] Major update (Breaking change E.g. Return code change / API behaviour change)

---

Test results

[] No Tests required for this change (E.g docs only update)
[] Covered by existing mbed-os tests (Greentea or Unittest)
[x] Tests / results supplied as part of this PR

---

Reviewers

@kjbracey-arm
@AnttiKauppila
@tymoteuszblochmobica

---

[ciarmcom]

@michalpasztamobica, thank you for your changes.
@AnttiKauppila @tymoteuszblochmobica @kjbracey-arm @ARMmbed/mbed-os-test @ARMmbed/mbed-os-ipcore @ARMmbed/mbed-os-maintainers please review.

[kjbracey]

Only question is whether reworking a broken API is a breaking change.

[bulislaw]

Hey some of the deprecated methods seem to be silently dropped, also is this a breaking change from the user's point of view?

[kjbracey]

OnboardNetworkStack::Interface is not visible to application-type code - it's visible to drivers like UbloxWifiInterface or whatever that have registered themselves with the OnboardNetworkStack. They would use those methods to implement their application-facing NetworkInterface methods.

The particular method being removed has no obvious use though - it is not needed to implement any NetworkInterface calls. It seems it was put into OnboardNetworkStack::Interface without any thought about what the layers were doing, and then LWIP implemented that instead of the NetworkStack::get_ip_address_if it should have implemented.

[michalpasztamobica]

@bulislaw , that is true - I did not move the string-based methods as they are on their way for removal anyway in another PR. Should I add them back?

@kjbracey-arm , just addressed the other question. Thanks, Kevin!

[bulislaw]

@bulislaw , that is true - I did not move the string-based methods as they are on their way for removal anyway in another PR. Should I add them back?

Nah, but can you explicitly remove them with a separate commit so it's accounted for?

[michalpasztamobica]

@bulislaw , I rearranged the commits, according to your suggestion. I hope I got it right?

[adbridge]

CI started

[mbed-ci]

Test run: SUCCESS

Summary: 11 of 11 test jobs passed
Build number : 1
Build artifacts