Use function pointers for interop in System.Net.NetworkInformation (d…

…otnet#52192)

src/libraries/Common/src/Interop/Unix/System.Native/Interop.EnumerateInterfaceAddresses.cs

@@ -42,19 +42,15 @@ public unsafe struct NetworkInterfaceInfo
             private fixed byte __padding[3];
         }
 
-        public unsafe delegate void IPv4AddressDiscoveredCallback(string ifaceName, IpAddressInfo* ipAddressInfo);
-        public unsafe delegate void IPv6AddressDiscoveredCallback(string ifaceName, IpAddressInfo* ipAddressInfo, uint* scopeId);
-        public unsafe delegate void LinkLayerAddressDiscoveredCallback(string ifaceName, LinkLayerAddressInfo* llAddress);
-        public unsafe delegate void DnsAddessDiscoveredCallback(IpAddressInfo* gatewayAddress);
-
         [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_EnumerateInterfaceAddresses")]
-        public static extern int EnumerateInterfaceAddresses(
-            IPv4AddressDiscoveredCallback ipv4Found,
-            IPv6AddressDiscoveredCallback? ipv6Found,
-            LinkLayerAddressDiscoveredCallback? linkLayerFound);
+        public static extern unsafe int EnumerateInterfaceAddresses(
+            void* context,
+            delegate* unmanaged<void*, byte*, IpAddressInfo*, void> ipv4Found,
+            delegate* unmanaged<void*, byte*, IpAddressInfo*, uint*, void> ipv6Found,
+            delegate* unmanaged<void*, byte*, LinkLayerAddressInfo*, void> linkLayerFound);
 
         [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_EnumerateGatewayAddressesForInterface")]
-        public static extern int EnumerateGatewayAddressesForInterface(uint interfaceIndex, DnsAddessDiscoveredCallback onGatewayFound);
+        public static extern unsafe int EnumerateGatewayAddressesForInterface(void* context, uint interfaceIndex, delegate* unmanaged<void*, IpAddressInfo*, void> onGatewayFound);
 
         [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_GetNetworkInterfaces")]
         public static unsafe extern int GetNetworkInterfaces(ref int count, ref NetworkInterfaceInfo* addrs, ref int addressCount, ref IpAddressInfo *aa);

src/libraries/Common/src/Interop/Unix/System.Native/Interop.NetworkChange.cs

@@ -16,15 +16,13 @@ public enum NetworkChangeKind
             AvailabilityChanged = 2
         }
 
-        public delegate void NetworkChangeEvent(int socket, NetworkChangeKind kind);
-
         [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_CreateNetworkChangeListenerSocket")]
         public static extern Error CreateNetworkChangeListenerSocket(out int socket);
 
         [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_CloseNetworkChangeListenerSocket")]
         public static extern Error CloseNetworkChangeListenerSocket(int socket);
 
         [DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_ReadEvents")]
-        public static extern void ReadEvents(int socket, NetworkChangeEvent onNetworkChange);
+        public static extern unsafe void ReadEvents(int socket, delegate* unmanaged<int, NetworkChangeKind, void> onNetworkChange);
     }
 }

src/libraries/Native/Unix/System.Native/pal_interfaceaddresses.c

@@ -95,7 +95,8 @@ static inline uint8_t mask2prefix(uint8_t* mask, int length)
 }
 #endif
 
-int32_t SystemNative_EnumerateInterfaceAddresses(IPv4AddressFound onIpv4Found,
+int32_t SystemNative_EnumerateInterfaceAddresses(void* context,
+                                               IPv4AddressFound onIpv4Found,
                                                IPv6AddressFound onIpv6Found,
                                                LinkLayerAddressFound onLinkLayerFound)
 {
@@ -142,7 +143,7 @@ int32_t SystemNative_EnumerateInterfaceAddresses(IPv4AddressFound onIpv4Found,
                 // ifa_netmask can be NULL according to documentation, probably P2P interfaces.
                 iai.PrefixLength = mask_sain != NULL ? mask2prefix((uint8_t*)&mask_sain->sin_addr.s_addr, NUM_BYTES_IN_IPV4_ADDRESS) : NUM_BYTES_IN_IPV4_ADDRESS * 8;
 
-                onIpv4Found(actualName, &iai);
+                onIpv4Found(context, actualName, &iai);
             }
         }
         else if (family == AF_INET6)
@@ -160,7 +161,7 @@ int32_t SystemNative_EnumerateInterfaceAddresses(IPv4AddressFound onIpv4Found,
 
                 struct sockaddr_in6* mask_sain6 = (struct sockaddr_in6*)current->ifa_netmask;
                 iai.PrefixLength = mask_sain6 != NULL ? mask2prefix((uint8_t*)&mask_sain6->sin6_addr.s6_addr, NUM_BYTES_IN_IPV6_ADDRESS) : NUM_BYTES_IN_IPV6_ADDRESS * 8;
-                onIpv6Found(actualName, &iai, &scopeId);
+                onIpv6Found(context, actualName, &iai, &scopeId);
             }
         }
 #if defined(AF_PACKET)
@@ -186,7 +187,7 @@ int32_t SystemNative_EnumerateInterfaceAddresses(IPv4AddressFound onIpv4Found,
                 lla.HardwareType = MapHardwareType(sall->sll_hatype);
 
                 memcpy_s(&lla.AddressBytes, sizeof_member(LinkLayerAddressInfo, AddressBytes), &sall->sll_addr, sall->sll_halen);
-                onLinkLayerFound(current->ifa_name, &lla);
+                onLinkLayerFound(context, current->ifa_name, &lla);
             }
         }
 #elif defined(AF_LINK)
@@ -223,7 +224,7 @@ int32_t SystemNative_EnumerateInterfaceAddresses(IPv4AddressFound onIpv4Found,
                 }
 #endif
                 memcpy_s(&lla.AddressBytes, sizeof_member(LinkLayerAddressInfo, AddressBytes), (uint8_t*)LLADDR(sadl), sadl->sdl_alen);
-                onLinkLayerFound(current->ifa_name, &lla);
+                onLinkLayerFound(context, current->ifa_name, &lla);
             }
         }
 #endif
@@ -233,6 +234,7 @@ int32_t SystemNative_EnumerateInterfaceAddresses(IPv4AddressFound onIpv4Found,
     return 0;
 #else
     // Not supported on e.g. Android. Also, prevent a compiler error because parameters are unused
+    (void)context;
     (void)onIpv4Found;
     (void)onIpv6Found;
     (void)onLinkLayerFound;
@@ -460,7 +462,7 @@ int32_t SystemNative_GetNetworkInterfaces(int32_t * interfaceCount, NetworkInter
 }
 
 #if HAVE_RT_MSGHDR && defined(CTL_NET)
-int32_t SystemNative_EnumerateGatewayAddressesForInterface(uint32_t interfaceIndex, GatewayAddressFound onGatewayFound)
+int32_t SystemNative_EnumerateGatewayAddressesForInterface(void* context, uint32_t interfaceIndex, GatewayAddressFound onGatewayFound)
 {
     static struct in6_addr anyaddr = IN6ADDR_ANY_INIT;
     int routeDumpName[] = {CTL_NET, AF_ROUTE, 0, 0, NET_RT_DUMP, 0};
@@ -558,16 +560,17 @@ int32_t SystemNative_EnumerateGatewayAddressesForInterface(uint32_t interfaceInd
                 // Ignore other address families.
                 continue;
             }
-            onGatewayFound(&iai);
+            onGatewayFound(context, &iai);
         }
     }
 
     free(buffer);
     return 0;
 }
 #else
-int32_t SystemNative_EnumerateGatewayAddressesForInterface(uint32_t interfaceIndex, GatewayAddressFound onGatewayFound)
+int32_t SystemNative_EnumerateGatewayAddressesForInterface(void* context, uint32_t interfaceIndex, GatewayAddressFound onGatewayFound)
 {
+    (void)context;
     (void)interfaceIndex;
     (void)onGatewayFound;
     errno = ENOTSUP;

src/libraries/Native/Unix/System.Native/pal_interfaceaddresses.h

@@ -47,13 +47,13 @@ typedef struct
     uint8_t __padding[3];
 } NetworkInterfaceInfo;
 
-typedef void (*IPv4AddressFound)(const char* interfaceName, IpAddressInfo* addressInfo);
-typedef void (*IPv6AddressFound)(const char* interfaceName, IpAddressInfo* info, uint32_t* scopeId);
-typedef void (*LinkLayerAddressFound)(const char* interfaceName, LinkLayerAddressInfo* llAddress);
-typedef void (*GatewayAddressFound)(IpAddressInfo* addressInfo);
+typedef void (*IPv4AddressFound)(void* context, const char* interfaceName, IpAddressInfo* addressInfo);
+typedef void (*IPv6AddressFound)(void* context, const char* interfaceName, IpAddressInfo* info, uint32_t* scopeId);
+typedef void (*LinkLayerAddressFound)(void* context, const char* interfaceName, LinkLayerAddressInfo* llAddress);
+typedef void (*GatewayAddressFound)(void* context, IpAddressInfo* addressInfo);
 
 PALEXPORT  int32_t SystemNative_EnumerateInterfaceAddresses(
-    IPv4AddressFound onIpv4Found, IPv6AddressFound onIpv6Found, LinkLayerAddressFound onLinkLayerFound);
+    void* context, IPv4AddressFound onIpv4Found, IPv6AddressFound onIpv6Found, LinkLayerAddressFound onLinkLayerFound);
 PALEXPORT int32_t SystemNative_GetNetworkInterfaces(int32_t * interfaceCount, NetworkInterfaceInfo** interfaces, int32_t * addressCount, IpAddressInfo **addressList);
 
-PALEXPORT int32_t SystemNative_EnumerateGatewayAddressesForInterface(uint32_t interfaceIndex, GatewayAddressFound onGatewayFound);
+PALEXPORT int32_t SystemNative_EnumerateGatewayAddressesForInterface(void* context, uint32_t interfaceIndex, GatewayAddressFound onGatewayFound);

src/libraries/System.Net.NetworkInformation/src/System.Net.NetworkInformation.csproj

@@ -194,6 +194,7 @@
     <Reference Include="System.Net.Primitives" />
     <Reference Include="System.Net.Sockets" />
     <Reference Include="System.Runtime" />
+    <Reference Include="System.Runtime.CompilerServices.Unsafe" />
     <Reference Include="System.Runtime.InteropServices" />
     <Reference Include="System.Threading" />
     <Reference Include="System.Threading.Overlapped" />

src/libraries/System.Net.NetworkInformation/src/System/Net/NetworkInformation/BsdIPv4GlobalStatistics.cs

@@ -2,6 +2,8 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Collections.Generic;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 
 namespace System.Net.NetworkInformation
 {
@@ -25,6 +27,21 @@ internal sealed class BsdIPv4GlobalStatistics : IPGlobalStatistics
         private readonly int _numIPAddresses;
         private readonly int _numRoutes;
 
+        private struct Context
+        {
+            internal int _numIPAddresses;
+            internal HashSet<string> _interfaceSet;
+        }
+
+        [UnmanagedCallersOnly]
+        private static unsafe void ProcessIpv4Address(void* pContext, byte* ifaceName, Interop.Sys.IpAddressInfo* ipAddr)
+        {
+            ref Context context = ref Unsafe.As<byte, Context>(ref *(byte*)pContext);
+
+            context._interfaceSet.Add(new string((sbyte*)ifaceName));
+            context._numIPAddresses++;
+        }
+
         public unsafe BsdIPv4GlobalStatistics()
         {
             Interop.Sys.IPv4GlobalStatistics statistics;
@@ -48,19 +65,18 @@ public unsafe BsdIPv4GlobalStatistics()
             _defaultTtl = statistics.DefaultTtl;
             _forwarding = statistics.Forwarding == 1;
 
-            HashSet<string> interfaceSet = new HashSet<string>();
-            int numIPAddresses = 0;
+            Context context;
+            context._numIPAddresses = 0;
+            context._interfaceSet = new HashSet<string>();
+
             Interop.Sys.EnumerateInterfaceAddresses(
-                (name, addressInfo) =>
-                {
-                    interfaceSet.Add(name);
-                    numIPAddresses++;
-                },
+                Unsafe.AsPointer(ref context),
+                &ProcessIpv4Address,
                 null,
                 null);
 
-            _numInterfaces = interfaceSet.Count;
-            _numIPAddresses = numIPAddresses;
+            _numInterfaces = context._interfaceSet.Count;
+            _numIPAddresses = context._numIPAddresses;
 
             _numRoutes = Interop.Sys.GetNumRoutes();
             if (_numRoutes == -1)

src/libraries/System.Net.NetworkInformation/src/System/Net/NetworkInformation/BsdIpInterfaceProperties.cs

@@ -2,6 +2,8 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Collections.Generic;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 
 namespace System.Net.NetworkInformation
 {
@@ -40,36 +42,43 @@ public override IPv6InterfaceProperties GetIPv6Properties()
             return _ipv6Properties;
         }
 
+        private struct Context
+        {
+            internal int _interfaceIndex;
+            internal HashSet<IPAddress> _addressSet;
+        }
+
         private static unsafe GatewayIPAddressInformationCollection GetGatewayAddresses(int interfaceIndex)
         {
-            HashSet<IPAddress> addressSet = new HashSet<IPAddress>();
-            if (Interop.Sys.EnumerateGatewayAddressesForInterface((uint)interfaceIndex,
-                (gatewayAddressInfo) =>
-                {
-                    byte[] ipBytes = new byte[gatewayAddressInfo->NumAddressBytes];
-                    fixed (byte* ipArrayPtr = ipBytes)
-                    {
-                        Buffer.MemoryCopy(gatewayAddressInfo->AddressBytes, ipArrayPtr, ipBytes.Length, ipBytes.Length);
-                    }
-                    IPAddress ipAddress = new IPAddress(ipBytes);
-                    if (ipAddress.IsIPv6LinkLocal)
-                    {
-                        // For Link-Local addresses add ScopeId as that is not part of the route entry.
-                        ipAddress.ScopeId = interfaceIndex;
-                    }
-                    addressSet.Add(ipAddress);
-                }) == -1)
+            Context context;
+            context._interfaceIndex = interfaceIndex;
+            context._addressSet = new HashSet<IPAddress>();
+            if (Interop.Sys.EnumerateGatewayAddressesForInterface(Unsafe.AsPointer(ref context), (uint)interfaceIndex, &OnGatewayFound) == -1)
             {
                 throw new NetworkInformationException(SR.net_PInvokeError);
             }
 
             GatewayIPAddressInformationCollection collection = new GatewayIPAddressInformationCollection();
-            foreach (IPAddress address in addressSet)
+            foreach (IPAddress address in context._addressSet)
             {
                 collection.InternalAdd(new SimpleGatewayIPAddressInformation(address));
             }
 
             return collection;
         }
+
+        [UnmanagedCallersOnly]
+        private static unsafe void OnGatewayFound(void* pContext, Interop.Sys.IpAddressInfo* gatewayAddressInfo)
+        {
+            ref Context context = ref Unsafe.As<byte, Context>(ref *(byte*)pContext);
+
+            IPAddress ipAddress = new IPAddress(new Span<byte>(gatewayAddressInfo->AddressBytes, gatewayAddressInfo->NumAddressBytes).ToArray());
+            if (ipAddress.IsIPv6LinkLocal)
+            {
+                // For Link-Local addresses add ScopeId as that is not part of the route entry.
+                ipAddress.ScopeId = context._interfaceIndex;
+            }
+            context._addressSet.Add(ipAddress);
+        }
     }
 }