[Windows] Fix Discovery of MAC Address

[CrystalP]

Description

Fix the CNetworkInterfaceWin32::GetHostMacAddress() function on Windows. It seems to have stopped working with PR #14369 which added support for IPv6.
A pointer dereference was missing and the wrong data was passed to the Windows API ResolveIpNetEntry2() for host discovery. It always failed with error 87 (ERROR_INVALID_PARAMETER).

For style, I could have gone the way below instead for the same result, but is it a safe way to copy structs of various sizes?

neighborIp.Address.Ipv4 = *reinterpret_cast<const struct sockaddr_in*>(host);
...
neighborIp.Address.Ipv6 = *reinterpret_cast<const struct sockaddr_in6*>(host);

Also added a small optimization to look for the host in the OS cache before hitting the wire with a resolution request.

I think this can be backported.

Motivation and context

Should fix the broken WOL issue reported in forum https://forum.kodi.tv/showthread.php?tid=377218 and #25058.

How has this been tested?

Windows 10, IPv4.
The hosts are resolved when activating the WOL setting of Kodi, toast messages appear and a wakeonlan.xml file with valid addresses is generated.

IPv6 support is not in a shape that allows testing of MAC resolution.

What is the effect on users?

Working WOL function on Windows.

Types of change

• Bug fix (non-breaking change which fixes an issue)
• Clean up (non-breaking change which removes non-working, unmaintained functionality)
• Improvement (non-breaking change which improves existing functionality)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that will cause existing functionality to change)
• Cosmetic change (non-breaking change that doesn't touch code)
• Student submission (PR was done for educational purposes and will be treated as such)
• None of the above (please explain below)

Checklist:

• My code follows the Code Guidelines of this project
• My change requires a change to the documentation, either Doxygen or wiki
• I have updated the documentation accordingly
• I have read the Contributing document
• I have added tests to cover my change
• All new and existing tests passed

[CrystalP]

Jenkins build this please

[thexai]

Good find!

Tested on windows 11 and is working.

[thexai]

Suggested change

	struct sockaddr sockHost = {};
	sockaddr sockHost = {};

Seems rare the use of "struct" word here. I mean struct is for define a struct but here is declare a struct already defined in Windows headers.

Same thing in CNetworkWin32::PingHost and CNetworkInterfaceWin32::GetHostMacAddress

[CrystalP]

True, I didn't question the unnecessary C syntax. That's the reason why the format bot insisted on weird formatting in the initialization. Changed, but it's not broken and I'm not changing the other ones of the file.

[Zebraitis]

May 5th v22 nightly User Acceptance Test results: The server wakes from sleep. But...

• It finds the MAC address if the Win11 NAS server shared sources are defined by IP Address.

• It fails MAC discovery if the Win11 NAS server shared sources are defined by samba name.

For me, this is a huge improvement. However, it does throw up the red MAC Discovery Fail message, which will likely cause confusion for some users.