fix: ignore duplicate disallowed networks or ones which contain another

- Call Distinct() before processing
- And remove any disallowed network which is already contained fully within another one, and
  thus has no effect. (This caused bugs in the calculation logic)

Author: fabyr

WireguardAllowedIPs/Core/Calculator.cs

@@ -38,8 +38,14 @@ public static IPv4Network[] CalculateAllowedIPv4s(IPv4Network[] allowed, IPv4Net
         if(disallowed.Length == 0)
             return allowed;
         List<IPv4Network> result = new();
+
+        // Remove duplicates
+        disallowed = disallowed.Distinct().ToArray();
 
-        IPv4Network[] sortedDisallowed = disallowed.OrderBy(x => x.GetLowAddressValue()).ToArray();
+        // Remove disallowed ranges which are already contained within another disallowed range
+        // Then sort by ascending address value
+        IPv4Network[] sortedDisallowed = disallowed.Where(x => !disallowed.Any(y => !x.Equals(y) && y.Contains(x)))
+                                         .OrderBy(x => x.GetLowAddressValue()).ToArray();
 
         IPv4Network last = new(0, 32);
 
@@ -73,7 +79,10 @@ public static IPv6Network[] CalculateAllowedIPv6s(IPv6Network[] allowed, IPv6Net
             return allowed;
         List<IPv6Network> result = new();
 
-        IPv6Network[] sortedDisallowed = disallowed.OrderBy(x => x.GetLowAddressValue()).ToArray();
+        disallowed = disallowed.Distinct().ToArray();
+        
+        IPv6Network[] sortedDisallowed = disallowed.Where(x => !disallowed.Any(y => !x.Equals(y) && y.Contains(x)))
+                                         .OrderBy(x => x.GetLowAddressValue()).ToArray();
 
         IPv6Network last = new(UInt128.Zero, 128);