Obsolete IPNetwork

[Tratcher]

The BCL is planning a replacement for this type: dotnet/runtime#79946

We should consume theirs when available and obsolete ours.

aspnetcore/src/Middleware/HttpOverrides/src/IPNetwork.cs

Line 13 in 83d6c56

public class IPNetwork

aspnetcore/src/Middleware/HttpOverrides/src/ForwardedHeadersOptions.cs

Line 73 in 83d6c56

public IList<IPNetwork> KnownNetworks { get; } = new List<IPNetwork>() { new IPNetwork(IPAddress.Loopback, 8) };

Consider adding an implicit converter to minimize the breaking changes in the short term.

[ghost]

Thanks for contacting us.

We're moving this issue to the .NET 8 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
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[stylpe]

This should no longer be blocked, right? I can make a PR for this if you'd like.

There are 3 concrete changes, right?

• Obsolete HttpOverrides.IPNetwork
• Add an implicit conversion from that class to System.Net.IPNetwork
• Change ForwardedHeadersOptions to use System.Net.IPNetwork

That should keep all existing usage working, I think.

[stylpe]

I started working on this proactively, and discovered that the HttpOverrides version accepts any IPAddress in the constructors (and masks it during each comparison), while the System.Net version only accepts a value that is a valid network prefix given the accompanying prefix length (which I knew, but I initially assumed the original HttpOverrides edition worked the same way). This obviously makes most of the tests go haywire since the test data is "bad" according to the new version.

So I'd propose the following additional changes:

• Expand the implicit conversion operator to apply the subnet mask to the IPAddress before passing it to the new class' constructor
• Scrub the test data to fit the new constraint
• Possibly even reimplement the HttpOverrides version to internally delegate everything to the System.Net version, then delete the IPNetwork tests (moving any cases to dotnet/runtime that are not already there)

But I suspect this difference might be too much of a breaking change in the first place to mark it obsolete?