Fix scope id test failures on mac and linux (#1754)

Author: halter73

src/Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv/Internal/Networking/SockAddr.cs

@@ -93,7 +93,20 @@ public unsafe IPEndPoint GetIPEndPoint()
                     *((long*)(b + 8)) = _field2;
                 }
 
-                return new IPEndPoint(new IPAddress(bytes, scopeid: _field3 & 0xFFFFFFFF), port);
+                return new IPEndPoint(new IPAddress(bytes, ScopeId), port);
+            }
+        }
+
+        public uint ScopeId
+        {
+            get
+            {
+                return (uint)_field3;
+            }
+            set
+            {
+                _field3 &= unchecked ((long)0xFFFFFFFF00000000);
+                _field3 |= value;
             }
         }
 

src/Microsoft.AspNetCore.Server.Kestrel.Transport.Libuv/Internal/Networking/UvTcpHandle.cs

@@ -44,6 +44,13 @@ public void Bind(IPEndPoint endPoint)
                 {
                     throw error1;
                 }
+
+                if (endPoint.Address.ScopeId != addr.ScopeId)
+                {
+                    // IPAddress.ScopeId cannot be less than 0 or greater than 0xFFFFFFFF
+                    // https://msdn.microsoft.com/en-us/library/system.net.ipaddress.scopeid(v=vs.110).aspx
+                    addr.ScopeId = (uint)endPoint.Address.ScopeId;
+                }
             }
 
             _uv.tcp_bind(this, ref addr, 0);

test/Microsoft.AspNetCore.Server.Kestrel.FunctionalTests/AddressRegistrationTests.cs

@@ -109,8 +109,6 @@ public async Task RegisterAddresses_IPv6Port80_Success(string addressInput, Func
         [ConditionalTheory, MemberData(nameof(AddressRegistrationDataIPv6ScopeId))]
         [IPv6SupportedCondition]
         [IPv6ScopeIdPresentCondition]
-        [OSSkipCondition(OperatingSystems.MacOSX, SkipReason = "Causing test failures")]
-        [OSSkipCondition(OperatingSystems.Linux, SkipReason = "Causing test failures")]
         public async Task RegisterAddresses_IPv6ScopeId_Success(string addressInput, Func<IServerAddressesFeature, string[]> testUrls)
         {
             await RegisterAddresses_Success(addressInput, testUrls);