Supporting auto network device

[SebaLukas]

Describe your changes

Now the first ipv6 interface is selected if the interface name is auto. Super helpful, running in the SIL.

Issue ticket number and link

Checklist before requesting a review

• I have performed a self-review of my code
• I have made corresponding changes to the documentation
• I read the contribution documentation and made sure that my changes meet its requirements

[MarzellT]

I mean it's not really part of this Pull Request, but why don't we return the address in the get_first_sockaddr_in6_for_interface function instead of returning bool? This seems to me like C style instead of C++.

[a-w50]

I mean it's not really part of this Pull Request, but why don't we return the address in the get_first_sockaddr_in6_for_interface function instead of returning bool? This seems to me like C style instead of C++.

You can't return address directly, because if no device is found, what would you return? One could use a std::optional<address> as return value or even a std::unique_ptr<address>. It depends quite a bit but I would agree that a std::optional might be the best option here.

[MarzellT]

I mean it's not really part of this Pull Request, but why don't we return the address in the get_first_sockaddr_in6_for_interface function instead of returning bool? This seems to me like C style instead of C++.

You can't return address directly, because if no device is found, what would you return? One could use a std::optional<address> as return value or even a std::unique_ptr<address>. It depends quite a bit but I would agree that a std::optional might be the best option here.

I think a std::optional or throwing an exception would be fitting but I just wanted to raise this to discuss using this style in general