1 /*
2 * junixsocket
3 *
4 * Copyright 2009-2026 Christian Kohlschütter
5 *
6 * Licensed under the Apache License, Version 2.0 (the "License");
7 * you may not use this file except in compliance with the License.
8 * You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18 package org.newsclub.net.unix.vsock;
19
20 import java.io.FileDescriptor;
21 import java.io.IOException;
22 import java.net.Socket;
23 import java.net.SocketException;
24
25 import org.newsclub.net.unix.AFSocket;
26 import org.newsclub.net.unix.AFSocketCapability;
27 import org.newsclub.net.unix.AFSocketFactory;
28 import org.newsclub.net.unix.AFVSOCKSocketAddress;
29 import org.newsclub.net.unix.AFVSOCKSocketImplExtensions;
30
31 import com.kohlschutter.annotations.compiletime.SuppressFBWarnings;
32
33 /**
34 * Implementation of an {@code AF_VSOCK} socket.
35 *
36 * @author Christian Kohlschütter
37 */
38 public final class AFVSOCKSocket extends AFSocket<AFVSOCKSocketAddress> implements
39 AFVSOCKSocketExtensions {
40 private static AFVSOCKSocketImplExtensions staticExtensions = null;
41
42 AFVSOCKSocket(FileDescriptor fdObj, AFSocketFactory<AFVSOCKSocketAddress> factory)
43 throws SocketException {
44 super(new AFVSOCKSocketImpl(fdObj), factory);
45 }
46
47 private static synchronized AFVSOCKSocketImplExtensions getStaticImplExtensions()
48 throws IOException {
49 if (staticExtensions == null) {
50 try (AFVSOCKSocket socket = new AFVSOCKSocket(null, null)) {
51 staticExtensions = (AFVSOCKSocketImplExtensions) socket.getImplExtensions();
52 }
53 }
54 return staticExtensions;
55 }
56
57 /**
58 * Returns <code>true</code> iff {@link AFVSOCKSocket}s (sockets of type "AF_VSOCK") are supported
59 * by the current Java VM and the kernel.
60 *
61 * To support {@link AFVSOCKSocket}s, a custom JNI library must be loaded that is supplied with
62 * <em>junixsocket</em>, and the system must support AF_VSOCK sockets.
63 *
64 * This call is equivalent to checking {@link AFSocket#isSupported()} and
65 * {@link AFSocket#supports(AFSocketCapability)} with {@link AFSocketCapability#CAPABILITY_VSOCK}.
66 *
67 * @return {@code true} iff supported.
68 */
69 @SuppressFBWarnings("HSM_HIDING_METHOD")
70 public static boolean isSupported() {
71 return AFSocket.isSupported() && AFSocket.supports(AFSocketCapability.CAPABILITY_VSOCK);
72 }
73
74 @Override
75 protected AFVSOCKSocketChannel newChannel() {
76 return new AFVSOCKSocketChannel(this);
77 }
78
79 /**
80 * Creates a new, unbound {@link AFSocket}.
81 *
82 * This "default" implementation is a bit "lenient" with respect to the specification.
83 *
84 * In particular, we ignore calls to {@link Socket#getTcpNoDelay()} and
85 * {@link Socket#setTcpNoDelay(boolean)}.
86 *
87 * @return A new, unbound socket.
88 * @throws IOException if the operation fails.
89 */
90 public static AFVSOCKSocket newInstance() throws IOException {
91 return (AFVSOCKSocket) AFSocket.newInstance(AFVSOCKSocket::new, (AFVSOCKSocketFactory) null);
92 }
93
94 static AFVSOCKSocket newInstance(AFVSOCKSocketFactory factory) throws SocketException {
95 return (AFVSOCKSocket) AFSocket.newInstance(AFVSOCKSocket::new, factory);
96 }
97
98 /**
99 * Creates a new, unbound, "strict" {@link AFSocket}.
100 *
101 * This call uses an implementation that tries to be closer to the specification than
102 * {@link #newInstance()}, at least for some cases.
103 *
104 * @return A new, unbound socket.
105 * @throws IOException if the operation fails.
106 */
107 public static AFVSOCKSocket newStrictInstance() throws IOException {
108 return (AFVSOCKSocket) AFSocket.newInstance(AFVSOCKSocket::new, (AFVSOCKSocketFactory) null);
109 }
110
111 /**
112 * Creates a new {@link AFSocket} and connects it to the given {@link AFVSOCKSocketAddress}.
113 *
114 * @param addr The address to connect to.
115 * @return A new, connected socket.
116 * @throws IOException if the operation fails.
117 */
118 public static AFVSOCKSocket connectTo(AFVSOCKSocketAddress addr) throws IOException {
119 return (AFVSOCKSocket) AFSocket.connectTo(AFVSOCKSocket::new, addr);
120 }
121
122 @Override
123 public AFVSOCKSocketChannel getChannel() {
124 return (AFVSOCKSocketChannel) super.getChannel();
125 }
126
127 /**
128 * Returns the local CID.
129 *
130 * If the system does not support vsock, or status about support cannot be retrieved, -1
131 * ({@link AFVSOCKSocketAddress#VMADDR_CID_ANY}) is returned. The value may be cached upon
132 * initialization of the library.
133 *
134 * @return The CID, or -1.
135 * @throws IOException on error.
136 */
137 public static int getLocalCID() throws IOException {
138 return getStaticImplExtensions().getLocalCID();
139 }
140
141 /**
142 * Very basic self-test function.
143 *
144 * Prints "supported" and "capabilities" status to System.out.
145 *
146 * @param args ignored.
147 */
148 public static void main(String[] args) {
149 // If you want to run this directly from within Eclipse, see
150 // org.newsclub.net.unix.vsock.SocketTest#testMain.
151 System.out.print(AFVSOCKSocket.class.getName() + ".isSupported(): ");
152 System.out.flush();
153 System.out.println(AFVSOCKSocket.isSupported());
154 }
155 }