okhttp3.internal.connection.ConnectionSpecSelector Maven / Gradle / Ivy
/*
* Copyright (C) 2015 Square, Inc.
*
* Licensed 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 okhttp3.internal.connection;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.ProtocolException;
import java.net.UnknownServiceException;
import java.security.cert.CertificateException;
import java.util.Arrays;
import java.util.List;
import javax.net.ssl.SSLHandshakeException;
import javax.net.ssl.SSLPeerUnverifiedException;
import javax.net.ssl.SSLProtocolException;
import javax.net.ssl.SSLSocket;
import okhttp3.ConnectionSpec;
import okhttp3.internal.Internal;
/**
* Handles the connection spec fallback strategy: When a secure socket connection fails due to a
* handshake / protocol problem the connection may be retried with different protocols. Instances
* are stateful and should be created and used for a single connection attempt.
*/
public final class ConnectionSpecSelector {
private final List connectionSpecs;
private int nextModeIndex;
private boolean isFallbackPossible;
private boolean isFallback;
public ConnectionSpecSelector(List connectionSpecs) {
this.nextModeIndex = 0;
this.connectionSpecs = connectionSpecs;
}
/**
* Configures the supplied {@link SSLSocket} to connect to the specified host using an appropriate
* {@link ConnectionSpec}. Returns the chosen {@link ConnectionSpec}, never {@code null}.
*
* @throws IOException if the socket does not support any of the TLS modes available
*/
public ConnectionSpec configureSecureSocket(SSLSocket sslSocket) throws IOException {
ConnectionSpec tlsConfiguration = null;
for (int i = nextModeIndex, size = connectionSpecs.size(); i < size; i++) {
ConnectionSpec connectionSpec = connectionSpecs.get(i);
if (connectionSpec.isCompatible(sslSocket)) {
tlsConfiguration = connectionSpec;
nextModeIndex = i + 1;
break;
}
}
if (tlsConfiguration == null) {
// This may be the first time a connection has been attempted and the socket does not support
// any the required protocols, or it may be a retry (but this socket supports fewer
// protocols than was suggested by a prior socket).
throw new UnknownServiceException(
"Unable to find acceptable protocols. isFallback=" + isFallback
+ ", modes=" + connectionSpecs
+ ", supported protocols=" + Arrays.toString(sslSocket.getEnabledProtocols()));
}
isFallbackPossible = isFallbackPossible(sslSocket);
Internal.instance.apply(tlsConfiguration, sslSocket, isFallback);
return tlsConfiguration;
}
/**
* Reports a failure to complete a connection. Determines the next {@link ConnectionSpec} to try,
* if any.
*
* @return {@code true} if the connection should be retried using {@link
* #configureSecureSocket(SSLSocket)} or {@code false} if not
*/
public boolean connectionFailed(IOException e) {
// Any future attempt to connect using this strategy will be a fallback attempt.
isFallback = true;
if (!isFallbackPossible) {
return false;
}
// If there was a protocol problem, don't recover.
if (e instanceof ProtocolException) {
return false;
}
// If there was an interruption or timeout (SocketTimeoutException), don't recover.
// For the socket connect timeout case we do not try the same host with a different
// ConnectionSpec: we assume it is unreachable.
if (e instanceof InterruptedIOException) {
return false;
}
// Look for known client-side or negotiation errors that are unlikely to be fixed by trying
// again with a different connection spec.
if (e instanceof SSLHandshakeException) {
// If the problem was a CertificateException from the X509TrustManager,
// do not retry.
if (e.getCause() instanceof CertificateException) {
return false;
}
}
if (e instanceof SSLPeerUnverifiedException) {
// e.g. a certificate pinning error.
return false;
}
// On Android, SSLProtocolExceptions can be caused by TLS_FALLBACK_SCSV failures, which means we
// retry those when we probably should not.
return (e instanceof SSLHandshakeException || e instanceof SSLProtocolException);
}
/**
* Returns {@code true} if any later {@link ConnectionSpec} in the fallback strategy looks
* possible based on the supplied {@link SSLSocket}. It assumes that a future socket will have the
* same capabilities as the supplied socket.
*/
private boolean isFallbackPossible(SSLSocket socket) {
for (int i = nextModeIndex; i < connectionSpecs.size(); i++) {
if (connectionSpecs.get(i).isCompatible(socket)) {
return true;
}
}
return false;
}
}