1 /*
2 * Copyright 2016 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * https://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package io.netty.channel.kqueue;
17
18 import io.netty.channel.ChannelOption;
19 import io.netty.channel.unix.FileDescriptor;
20 import io.netty.util.internal.SystemPropertyUtil;
21 import io.netty.util.internal.logging.InternalLogger;
22 import io.netty.util.internal.logging.InternalLoggerFactory;
23
24 /**
25 * If KQueue is available the JNI resources will be loaded when this class loads.
26 */
27 public final class KQueue {
28 private static final Throwable UNAVAILABILITY_CAUSE;
29
30 static {
31 Throwable cause = null;
32 if (SystemPropertyUtil.getBoolean("io.netty.transport.noNative", false)) {
33 cause = new UnsupportedOperationException(
34 "Native transport was explicit disabled with -Dio.netty.transport.noNative=true");
35 } else {
36 FileDescriptor kqueueFd = null;
37 try {
38 kqueueFd = Native.newKQueue();
39 } catch (Throwable t) {
40 cause = t;
41 } finally {
42 if (kqueueFd != null) {
43 try {
44 kqueueFd.close();
45 } catch (Exception ignore) {
46 // ignore
47 }
48 }
49 }
50 }
51 if (cause != null) {
52 InternalLogger logger = InternalLoggerFactory.getInstance(KQueue.class);
53 if (logger.isTraceEnabled()) {
54 logger.debug("KQueue support is not available", cause);
55 } else if (logger.isDebugEnabled()) {
56 logger.debug("KQueue support is not available: {}", cause.getMessage());
57 }
58 }
59 UNAVAILABILITY_CAUSE = cause;
60 }
61
62 /**
63 * Returns {@code true} if and only if the <a href="https://netty.io/wiki/native-transports.html">{@code
64 * netty-transport-native-kqueue}</a> is available.
65 */
66 public static boolean isAvailable() {
67 return UNAVAILABILITY_CAUSE == null;
68 }
69
70 /**
71 * Ensure that <a href="https://netty.io/wiki/native-transports.html">{@code netty-transport-native-kqueue}</a> is
72 * available.
73 *
74 * @throws UnsatisfiedLinkError if unavailable
75 */
76 public static void ensureAvailability() {
77 if (UNAVAILABILITY_CAUSE != null) {
78 throw (Error) new UnsatisfiedLinkError(
79 "failed to load the required native library").initCause(UNAVAILABILITY_CAUSE);
80 }
81 }
82
83 /**
84 * Returns the cause of unavailability of <a href="https://netty.io/wiki/native-transports.html">{@code
85 * netty-transport-native-kqueue}</a>.
86 *
87 * @return the cause if unavailable. {@code null} if available.
88 */
89 public static Throwable unavailabilityCause() {
90 return UNAVAILABILITY_CAUSE;
91 }
92
93 /**
94 * Returns {@code true} if the kqueue native transport is both {@linkplain #isAvailable() available} and supports
95 * {@linkplain ChannelOption#TCP_FASTOPEN_CONNECT client-side TCP FastOpen}.
96 *
97 * @return {@code true} if it's possible to use client-side TCP FastOpen via kqueue, otherwise {@code false}.
98 */
99 public static boolean isTcpFastOpenClientSideAvailable() {
100 return isAvailable() && Native.IS_SUPPORTING_TCP_FASTOPEN_CLIENT;
101 }
102
103 /**
104 * Returns {@code true} if the kqueue native transport is both {@linkplain #isAvailable() available} and supports
105 * {@linkplain ChannelOption#TCP_FASTOPEN server-side TCP FastOpen}.
106 *
107 * @return {@code true} if it's possible to use server-side TCP FastOpen via kqueue, otherwise {@code false}.
108 */
109 public static boolean isTcpFastOpenServerSideAvailable() {
110 return isAvailable() && Native.IS_SUPPORTING_TCP_FASTOPEN_SERVER;
111 }
112
113 private KQueue() {
114 }
115 }