dotnet · jkotas · Jun 17, 2022 · Jun 17, 2022 · Jun 17, 2022
diff --git a/src/libraries/Common/src/Interop/Windows/IpHlpApi/Interop.FIXED_INFO.cs b/src/libraries/Common/src/Interop/Windows/IpHlpApi/Interop.FIXED_INFO.cs
@@ -12,21 +12,34 @@ internal static partial class IpHlpApi
         public const int MAX_DOMAIN_NAME_LEN = 128;
         public const int MAX_SCOPE_ID_LEN = 256;
 
-        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
-        public struct FIXED_INFO
+        [StructLayout(LayoutKind.Sequential)]
+        public unsafe struct FIXED_INFO
         {
-            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAX_HOSTNAME_LEN + 4)]
-            public string hostName;
-            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAX_DOMAIN_NAME_LEN + 4)]
-            public string domainName;
+            private fixed byte _hostName[MAX_HOSTNAME_LEN + 4];
+            public string HostName => CreateString(ref _hostName[0], MAX_HOSTNAME_LEN + 4);
+
+            private fixed byte _domainName[MAX_DOMAIN_NAME_LEN + 4];
+            public string DomainName => CreateString(ref _domainName[0], MAX_DOMAIN_NAME_LEN + 4);
+
             public IntPtr currentDnsServer; // IpAddressList*
             public IP_ADDR_STRING DnsServerList;
             public uint nodeType;
-            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = MAX_SCOPE_ID_LEN + 4)]
-            public string scopeId;
-            public bool enableRouting;
-            public bool enableProxy;
-            public bool enableDns;
+
+            private fixed byte _scopeId[MAX_SCOPE_ID_LEN + 4];
+            public string ScopeId => CreateString(ref _scopeId[0], MAX_SCOPE_ID_LEN + 4);
+
+            public uint enableRouting;
+            public uint enableProxy;
+            public uint enableDns;
+
+            private static string CreateString(ref byte firstByte, int maxLength)
+            {
+                fixed (byte* ptr = &firstByte)
+                {
+                    int terminator = new ReadOnlySpan<byte>(ptr, maxLength).IndexOf((byte)0);
+                    return Marshal.PtrToStringAnsi((IntPtr)ptr, (terminator >= 0) ? terminator : maxLength);
+                }
+            }
         }
     }
 }
diff --git a/src/libraries/Common/src/Interop/Windows/IpHlpApi/Interop.ICMP.cs b/src/libraries/Common/src/Interop/Windows/IpHlpApi/Interop.ICMP.cs
@@ -13,15 +13,15 @@ internal static partial class IpHlpApi
         internal const int IP_STATUS_BASE = 11000;
 
         [StructLayout(LayoutKind.Sequential)]
-        internal struct IPOptions
+        internal struct IP_OPTION_INFORMATION
         {
             internal byte ttl;
             internal byte tos;
             internal byte flags;
             internal byte optionsSize;
             internal IntPtr optionsData;
 
-            internal IPOptions(PingOptions? options)
+            internal IP_OPTION_INFORMATION(PingOptions? options)
             {
                 ttl = 128;
                 tos = 0;
@@ -42,39 +42,38 @@ internal IPOptions(PingOptions? options)
         }
 
         [StructLayout(LayoutKind.Sequential)]
-        internal struct IcmpEchoReply
+        internal struct ICMP_ECHO_REPLY
         {
             internal uint address;
             internal uint status;
             internal uint roundTripTime;
             internal ushort dataSize;
             internal ushort reserved;
             internal IntPtr data;
-            internal IPOptions options;
+            internal IP_OPTION_INFORMATION options;
         }
 
         [StructLayout(LayoutKind.Sequential, Pack = 1)]
-        internal struct Ipv6Address
+        internal unsafe struct IPV6_ADDRESS_EX
         {
-            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 6)]
-            internal byte[] Goo;
-            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 16)]
+            internal ushort port;
+            internal uint flowinfo;
+
             // Replying address.
-            internal byte[] Address;
+            private fixed byte _Address[16];
+            internal byte[] Address => MemoryMarshal.CreateReadOnlySpan(ref _Address[0], 16).ToArray();
+
             internal uint ScopeID;
         }
 
         [StructLayout(LayoutKind.Sequential)]
-        internal struct Icmp6EchoReply
+        internal struct ICMPV6_ECHO_REPLY
         {
-            internal Ipv6Address Address;
+            internal IPV6_ADDRESS_EX Address;
             // Reply IP_STATUS.
             internal uint Status;
             // RTT in milliseconds.
             internal uint RoundTripTime;
-            internal IntPtr data;
-            // internal IPOptions options;
-            // internal IntPtr data; data os after tjos
         }
 
         internal sealed class SafeCloseIcmpHandle : SafeHandleZeroOrMinusOneIsInvalid
@@ -101,10 +100,10 @@ protected override bool ReleaseHandle()
 
         [LibraryImport(Interop.Libraries.IpHlpApi, SetLastError = true)]
         internal static partial uint IcmpSendEcho2(SafeCloseIcmpHandle icmpHandle, SafeWaitHandle Event, IntPtr apcRoutine, IntPtr apcContext,
-            uint ipAddress, SafeLocalAllocHandle data, ushort dataSize, ref IPOptions options, SafeLocalAllocHandle replyBuffer, uint replySize, uint timeout);
+            uint ipAddress, SafeLocalAllocHandle data, ushort dataSize, ref IP_OPTION_INFORMATION options, SafeLocalAllocHandle replyBuffer, uint replySize, uint timeout);
 
         [LibraryImport(Interop.Libraries.IpHlpApi, SetLastError = true)]
         internal static partial uint Icmp6SendEcho2(SafeCloseIcmpHandle icmpHandle, SafeWaitHandle Event, IntPtr apcRoutine, IntPtr apcContext,
-            byte[] sourceSocketAddress, byte[] destSocketAddress, SafeLocalAllocHandle data, ushort dataSize, ref IPOptions options, SafeLocalAllocHandle replyBuffer, uint replySize, uint timeout);
+            byte[] sourceSocketAddress, byte[] destSocketAddress, SafeLocalAllocHandle data, ushort dataSize, ref IP_OPTION_INFORMATION options, SafeLocalAllocHandle replyBuffer, uint replySize, uint timeout);
     }
 }
diff --git a/src/libraries/Common/src/Interop/Windows/IpHlpApi/Interop.IP_ADDR_STRING.cs b/src/libraries/Common/src/Interop/Windows/IpHlpApi/Interop.IP_ADDR_STRING.cs
@@ -8,14 +8,12 @@ internal static partial class Interop
 {
     internal static partial class IpHlpApi
     {
-        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
-        public struct IP_ADDR_STRING
+        [StructLayout(LayoutKind.Sequential)]
+        public unsafe struct IP_ADDR_STRING
         {
-            public IntPtr Next; // struct _IpAddressList*
-            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)]
-            public string IpAddress;
-            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 16)]
-            public string IpMask;
+            public IP_ADDR_STRING* Next;
+            public fixed byte IpAddress[16];
+            public fixed byte IpMask[16];
             public uint Context;
         }
     }

diff --git a/src/libraries/Common/src/Interop/Windows/IpHlpApi/Interop.NetworkInformation.cs b/src/libraries/Common/src/Interop/Windows/IpHlpApi/Interop.NetworkInformation.cs
@@ -157,14 +157,7 @@ internal unsafe struct IpAdapterAddresses
 
             private fixed byte _address[MAX_ADAPTER_ADDRESS_LENGTH];
             private uint _addressLength;
-            internal byte[] Address
-            {
-                get
-                {
-                    fixed (byte* pAddress = _address)
-                        return new ReadOnlySpan<byte>(pAddress, (int)_addressLength).ToArray();
-                }
-            }
+            internal byte[] Address => MemoryMarshal.CreateReadOnlySpan<byte>(ref _address[0], (int)_addressLength).ToArray();
 
             internal AdapterFlags flags;
             internal uint mtu;
@@ -173,14 +166,7 @@ internal byte[] Address
             internal uint ipv6Index;
 
             private fixed uint _zoneIndices[16];
-            internal uint[] ZoneIndices
-            {
-                get
-                {
-                    fixed (uint* pZoneIndices = _zoneIndices)
-                        return new ReadOnlySpan<uint>(pZoneIndices, 16).ToArray();
-                }
-            }
+            internal uint[] ZoneIndices => MemoryMarshal.CreateReadOnlySpan<uint>(ref _zoneIndices[0], 16).ToArray();
 
             internal IntPtr firstPrefix;
 

diff --git a/src/libraries/Common/src/System/Net/NetworkInformation/HostInformationPal.Windows.cs b/src/libraries/Common/src/System/Net/NetworkInformation/HostInformationPal.Windows.cs
@@ -12,61 +12,113 @@ namespace System.Net.NetworkInformation
     internal static class HostInformationPal
     {
         // Changing this information requires a reboot, so it's safe to cache.
-        private static Interop.IpHlpApi.FIXED_INFO s_fixedInfo;
-        private static bool s_fixedInfoInitialized;
+        private static string? s_hostName;
+        private static string? s_domainName;
+        private static uint s_nodeType;
+        private static string? s_scopeId;
+        private static bool s_enableRouting;
+        private static bool s_enableProxy;
+        private static bool s_enableDns;
+
+        private static volatile bool s_initialized;
         private static object s_syncObject = new object();
 
         public static string GetHostName()
         {
-            return FixedInfo.hostName;
+            EnsureInitialized();
+            return s_hostName!;
         }
 
         public static string GetDomainName()
         {
-            return FixedInfo.domainName;
+            EnsureInitialized();
+            return s_domainName!;
+        }
+
+        public static uint GetNodeType()
+        {
+            EnsureInitialized();
+            return s_nodeType;
+        }
+
+        public static string GetScopeId()
+        {
+            EnsureInitialized();
+            return s_scopeId!;
+        }
+
+        public static bool GetEnableRouting()
+        {
+            EnsureInitialized();
+            return s_enableRouting;
         }
 
-        private static unsafe Interop.IpHlpApi.FIXED_INFO GetFixedInfo()
+        public static bool GetEnableProxy()
         {
-            uint size = 0;
-            Interop.IpHlpApi.FIXED_INFO fixedInfo = default;
+            EnsureInitialized();
+            return s_enableProxy;
+        }
 
-            // First we need to get the size of the buffer
-            uint result = Interop.IpHlpApi.GetNetworkParams(IntPtr.Zero, &size);
+        public static bool GetEnableDns()
+        {
+            EnsureInitialized();
+            return s_enableDns;
+        }
 
-            while (result == Interop.IpHlpApi.ERROR_BUFFER_OVERFLOW)
+        private static void EnsureInitialized()
+        {
+            if (!s_initialized)
+                Initialize();
+        }
+
+        private static unsafe void Initialize()
+        {
+            lock (s_syncObject)
             {
-                IntPtr buffer = Marshal.AllocHGlobal((int)size);
-                try
+                if (s_initialized)
+                    return;
+
+                uint size = 0;
+
+                // First we need to get the size of the buffer
+                uint result = Interop.IpHlpApi.GetNetworkParams(IntPtr.Zero, &size);
+
+                while (result == Interop.IpHlpApi.ERROR_BUFFER_OVERFLOW)
                 {
-                    result = Interop.IpHlpApi.GetNetworkParams(buffer, &size);
-                    if (result == Interop.IpHlpApi.ERROR_SUCCESS)
+                    IntPtr buffer = Marshal.AllocHGlobal((int)size);
+                    try
                     {
-                        fixedInfo = Marshal.PtrToStructure<Interop.IpHlpApi.FIXED_INFO>(buffer);
+                        result = Interop.IpHlpApi.GetNetworkParams(buffer, &size);
+                        if (result == Interop.IpHlpApi.ERROR_SUCCESS)
+                        {
+                            Interop.IpHlpApi.FIXED_INFO* pFixedInfo = (Interop.IpHlpApi.FIXED_INFO*)buffer;
+
+                            s_hostName = pFixedInfo->HostName;
+                            s_domainName = pFixedInfo->DomainName;
+
+                            s_hostName = pFixedInfo->HostName;
+                            s_domainName = pFixedInfo->DomainName;
+                            s_nodeType = pFixedInfo->nodeType;
+                            s_scopeId = pFixedInfo->ScopeId;
+                            s_enableRouting = pFixedInfo->enableRouting != 0;
+                            s_enableProxy = pFixedInfo->enableProxy != 0;
+                            s_enableDns = pFixedInfo->enableDns != 0;
+
+                            s_initialized = true;
+                        }
+                    }
+                    finally
+                    {
+                        Marshal.FreeHGlobal(buffer);
                     }
                 }
-                finally
+
+                // If the result include there being no information, we'll still throw
+                if (result != Interop.IpHlpApi.ERROR_SUCCESS)
                 {
-                    Marshal.FreeHGlobal(buffer);
+                    throw new Win32Exception((int)result);
                 }
             }
-
-            // If the result include there being no information, we'll still throw
-            if (result != Interop.IpHlpApi.ERROR_SUCCESS)
-            {
-                throw new Win32Exception((int)result);
-            }
-
-            return fixedInfo;
-        }
-
-        public static ref readonly Interop.IpHlpApi.FIXED_INFO FixedInfo
-        {
-            get
-            {
-                LazyInitializer.EnsureInitialized(ref s_fixedInfo, ref s_fixedInfoInitialized, ref s_syncObject, () => GetFixedInfo());
-                return ref s_fixedInfo;
-            }
         }
     }
 }
diff --git a/...stem.Net.NetworkInformation/src/System/Net/NetworkInformation/SystemIPGlobalProperties.cs b/...stem.Net.NetworkInformation/src/System/Net/NetworkInformation/SystemIPGlobalProperties.cs
@@ -19,7 +19,7 @@ public override string HostName
         {
             get
             {
-                return HostInformationPal.FixedInfo.hostName;
+                return HostInformationPal.GetHostName();
             }
         }
 
@@ -28,7 +28,7 @@ public override string DomainName
         {
             get
             {
-                return HostInformationPal.FixedInfo.domainName;
+                return HostInformationPal.GetDomainName();
             }
         }
 
@@ -48,7 +48,7 @@ public override NetBiosNodeType NodeType
         {
             get
             {
-                return (NetBiosNodeType)HostInformationPal.FixedInfo.nodeType;
+                return (NetBiosNodeType)HostInformationPal.GetNodeType();
             }
         }
 
@@ -57,7 +57,7 @@ public override string DhcpScopeName
         {
             get
             {
-                return HostInformationPal.FixedInfo.scopeId;
+                return HostInformationPal.GetScopeId();
             }
         }
 
@@ -66,7 +66,7 @@ public override bool IsWinsProxy
         {
             get
             {
-                return (HostInformationPal.FixedInfo.enableProxy);
+                return HostInformationPal.GetEnableProxy();
             }
         }
 

diff --git a/...m.Net.NetworkInformation/src/System/Net/NetworkInformation/SystemIPInterfaceProperties.cs b/...m.Net.NetworkInformation/src/System/Net/NetworkInformation/SystemIPInterfaceProperties.cs
@@ -26,11 +26,11 @@ internal sealed class SystemIPInterfaceProperties : IPInterfaceProperties
         private readonly GatewayIPAddressInformationCollection _gatewayAddresses;
         private readonly InternalIPAddressCollection _dhcpServers;
 
-        internal SystemIPInterfaceProperties(in Interop.IpHlpApi.FIXED_INFO fixedInfo, in Interop.IpHlpApi.IpAdapterAddresses ipAdapterAddresses)
+        internal SystemIPInterfaceProperties(in Interop.IpHlpApi.IpAdapterAddresses ipAdapterAddresses)
         {
             _adapterFlags = ipAdapterAddresses.flags;
             _dnsSuffix = ipAdapterAddresses.DnsSuffix;
-            _dnsEnabled = fixedInfo.enableDns;
+            _dnsEnabled = HostInformationPal.GetEnableDns();
             _dynamicDnsEnabled = ((ipAdapterAddresses.flags & Interop.IpHlpApi.AdapterFlags.DnsEnabled) > 0);
 
             _multicastAddresses = SystemMulticastIPAddressInformation.ToMulticastIpAddressInformationCollection(
@@ -58,7 +58,7 @@ internal SystemIPInterfaceProperties(in Interop.IpHlpApi.FIXED_INFO fixedInfo, i
 
             if ((_adapterFlags & Interop.IpHlpApi.AdapterFlags.IPv4Enabled) != 0)
             {
-                _ipv4Properties = new SystemIPv4InterfaceProperties(fixedInfo, ipAdapterAddresses);
+                _ipv4Properties = new SystemIPv4InterfaceProperties(ipAdapterAddresses);
             }
 
             if ((_adapterFlags & Interop.IpHlpApi.AdapterFlags.IPv6Enabled) != 0)