Rendezvous/src/FinalFactory.Rendezvous.Server/Abuse/TrustedProxyForwarding.cs

using System.Net;
using Microsoft.AspNetCore.HttpOverrides;

namespace FinalFactory.Rendezvous.Server.Abuse;

internal static class TrustedProxyForwarding
{
    public static bool IsEnabled(AbuseProtectionOptions options) =>
        options.TrustedProxyAddresses is { Length: > 0 };

    public static void Configure(
        ForwardedHeadersOptions forwarded,
        AbuseProtectionOptions abuse)
    {
        forwarded.ForwardedHeaders = ForwardedHeaders.XForwardedFor;
        forwarded.ForwardLimit = 1;
        forwarded.KnownProxies.Clear();
        forwarded.KnownIPNetworks.Clear();
        foreach (string address in abuse.TrustedProxyAddresses ?? [])
        {
            forwarded.KnownProxies.Add(IPAddress.Parse(address));
        }
    }
}