If user explicit ask to use an Inet6Address we should try to do so in… (#10415)

Motivation:

Even if the system does not support ipv6 we should try to use it if the user explicit pass an Inet6Address. This way we ensure we fail and not try to convert this to an ipv4 address internally.

This incorrect behavior was introduced by 70731bfa7e

Modifications:

If the user explicit passed an Inet6Address we force the usage of ipv6

Result:

Fixes https://github.com/netty/netty/issues/10402

transport-native-epoll/src/test/java/io/netty/channel/epoll/LinuxSocketTest.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2020 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.channel.epoll;
+
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+
+import static org.junit.Assume.assumeTrue;
+
+public class LinuxSocketTest {
+    @BeforeClass
+    public static void loadJNI() {
+        assumeTrue(Epoll.isAvailable());
+    }
+
+    @Test(expected = IOException.class)
+    public void testBindNonIpv6SocketToInet6AddressThrows() throws Exception {
+        LinuxSocket socket = LinuxSocket.newSocketStream(false);
+        try {
+            socket.bind(new InetSocketAddress(InetAddress.getByAddress(
+                    new byte[]{'0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '1'}), 0));
+        } finally {
+            socket.close();
+        }
+    }
+
+    @Test(expected = IOException.class)
+    public void testConnectNonIpv6SocketToInet6AddressThrows() throws Exception {
+        LinuxSocket socket = LinuxSocket.newSocketStream(false);
+        try {
+            socket.connect(new InetSocketAddress(InetAddress.getByAddress(
+                    new byte[]{'0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '1'}), 1234));
+        } finally {
+            socket.close();
+        }
+    }
+}

transport-native-unix-common/src/main/java/io/netty/channel/unix/Socket.java

@@ -55,6 +55,13 @@ public class Socket extends FileDescriptor {
         this.ipv6 = isIPv6(fd);
     }
 
+    /**
+     * Returns {@code true} if we should use IPv6 internally, {@code false} otherwise.
+     */
+    private boolean useIpv6(InetAddress address) {
+        return ipv6 || address instanceof Inet6Address;
+    }
+
     public final void shutdown() throws IOException {
         shutdown(true, true);
     }
@@ -117,7 +124,7 @@ public class Socket extends FileDescriptor {
             scopeId = 0;
             address = ipv4MappedIpv6Address(addr.getAddress());
         }
-        int res = sendTo(fd, ipv6, buf, pos, limit, address, scopeId, port);
+        int res = sendTo(fd, useIpv6(addr), buf, pos, limit, address, scopeId, port);
         if (res >= 0) {
             return res;
         }
@@ -141,7 +148,7 @@ public class Socket extends FileDescriptor {
             scopeId = 0;
             address = ipv4MappedIpv6Address(addr.getAddress());
         }
-        int res = sendToAddress(fd, ipv6, memoryAddress, pos, limit, address, scopeId, port);
+        int res = sendToAddress(fd, useIpv6(addr), memoryAddress, pos, limit, address, scopeId, port);
         if (res >= 0) {
             return res;
         }
@@ -164,7 +171,7 @@ public class Socket extends FileDescriptor {
             scopeId = 0;
             address = ipv4MappedIpv6Address(addr.getAddress());
         }
-        int res = sendToAddresses(fd, ipv6, memoryAddress, length, address, scopeId, port);
+        int res = sendToAddresses(fd, useIpv6(addr), memoryAddress, length, address, scopeId, port);
         if (res >= 0) {
             return res;
         }
@@ -215,8 +222,9 @@ public class Socket extends FileDescriptor {
         int res;
         if (socketAddress instanceof InetSocketAddress) {
             InetSocketAddress inetSocketAddress = (InetSocketAddress) socketAddress;
-            NativeInetAddress address = NativeInetAddress.newInstance(inetSocketAddress.getAddress());
+            InetAddress inetAddress = inetSocketAddress.getAddress();
-            res = connect(fd, ipv6, address.address, address.scopeId, inetSocketAddress.getPort());
+            NativeInetAddress address = NativeInetAddress.newInstance(inetAddress);
+            res = connect(fd, useIpv6(inetAddress), address.address, address.scopeId, inetSocketAddress.getPort());
         } else if (socketAddress instanceof DomainSocketAddress) {
             DomainSocketAddress unixDomainSocketAddress = (DomainSocketAddress) socketAddress;
             res = connectDomainSocket(fd, unixDomainSocketAddress.path().getBytes(CharsetUtil.UTF_8));
@@ -255,8 +263,9 @@ public class Socket extends FileDescriptor {
     public final void bind(SocketAddress socketAddress) throws IOException {
         if (socketAddress instanceof InetSocketAddress) {
             InetSocketAddress addr = (InetSocketAddress) socketAddress;
-            NativeInetAddress address = NativeInetAddress.newInstance(addr.getAddress());
+            InetAddress inetAddress = addr.getAddress();
-            int res = bind(fd, ipv6, address.address, address.scopeId, addr.getPort());
+            NativeInetAddress address = NativeInetAddress.newInstance(inetAddress);
+            int res = bind(fd, useIpv6(inetAddress), address.address, address.scopeId, addr.getPort());
             if (res < 0) {
                 throw newIOException("bind", res);
             }