/*
    * Copyright 2014 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.handler.ssl;
  
  import io.netty.buffer.ByteBufAllocator;
  import io.netty.util.internal.EmptyArrays;
  import io.netty.util.internal.logging.InternalLogger;
  import io.netty.util.internal.logging.InternalLoggerFactory;
  
  import java.io.File;
  import java.io.IOException;
  import java.security.InvalidAlgorithmParameterException;
  import java.security.KeyException;
  import java.security.KeyStore;
  import java.security.KeyStoreException;
  import java.security.NoSuchAlgorithmException;
  import java.security.PrivateKey;
  import java.security.Security;
  import java.security.UnrecoverableKeyException;
  import java.security.cert.CertificateException;
  import java.security.cert.X509Certificate;
  import java.security.spec.InvalidKeySpecException;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  
  import javax.crypto.NoSuchPaddingException;
  import javax.net.ssl.KeyManagerFactory;
  import javax.net.ssl.SSLContext;
  import javax.net.ssl.SSLEngine;
  import javax.net.ssl.SSLSessionContext;
  
  import static io.netty.handler.ssl.SslUtils.DEFAULT_CIPHER_SUITES;
  import static io.netty.handler.ssl.SslUtils.addIfSupported;
  import static io.netty.handler.ssl.SslUtils.useFallbackCiphersIfDefaultIsEmpty;
  import static io.netty.util.internal.ObjectUtil.checkNotNull;
  
  /**
   * An {@link SslContext} which uses JDK's SSL/TLS implementation.
   */
  public class JdkSslContext extends SslContext {
  
      private static final InternalLogger logger = InternalLoggerFactory.getInstance(JdkSslContext.class);
  
      static final String PROTOCOL = "TLS";
      private static final String[] DEFAULT_PROTOCOLS;
      private static final List<String> DEFAULT_CIPHERS;
      private static final Set<String> SUPPORTED_CIPHERS;
  
      static {
          SSLContext context;
          int i;
          try {
              context = SSLContext.getInstance(PROTOCOL);
              context.init(null, null, null);
          } catch (Exception e) {
              throw new Error("failed to initialize the default SSL context", e);
          }
  
          SSLEngine engine = context.createSSLEngine();
  
          // Choose the sensible default list of protocols.
          final String[] supportedProtocols = engine.getSupportedProtocols();
          Set<String> supportedProtocolsSet = new HashSet<String>(supportedProtocols.length);
          for (i = 0; i < supportedProtocols.length; ++i) {
              supportedProtocolsSet.add(supportedProtocols[i]);
          }
          List<String> protocols = new ArrayList<String>();
          addIfSupported(
                  supportedProtocolsSet, protocols,
                  "TLSv1.2", "TLSv1.1", "TLSv1");
  
          if (!protocols.isEmpty()) {
              DEFAULT_PROTOCOLS = protocols.toArray(new String[protocols.size()]);
          } else {
              DEFAULT_PROTOCOLS = engine.getEnabledProtocols();
          }
  
          // Choose the sensible default list of cipher suites.
          final String[] supportedCiphers = engine.getSupportedCipherSuites();
          SUPPORTED_CIPHERS = new HashSet<String>(supportedCiphers.length);
          for (i = 0; i < supportedCiphers.length; ++i) {
             String supportedCipher = supportedCiphers[i];
             SUPPORTED_CIPHERS.add(supportedCipher);
             // IBM's J9 JVM utilizes a custom naming scheme for ciphers and only returns ciphers with the "SSL_"
             // prefix instead of the "TLS_" prefix (as defined in the JSSE cipher suite names [1]). According to IBM's
             // documentation [2] the "SSL_" prefix is "interchangeable" with the "TLS_" prefix.
             // See the IBM forum discussion [3] and issue on IBM's JVM [4] for more details.
             //[1] http://docs.oracle.com/javase/8/docs/technotes/guides/security/StandardNames.html#ciphersuites
             //[2] https://www.ibm.com/support/knowledgecenter/en/SSYKE2_8.0.0/com.ibm.java.security.component.80.doc/
             // security-component/jsse2Docs/ciphersuites.html
             //[3] https://www.ibm.com/developerworks/community/forums/html/topic?id=9b5a56a9-fa46-4031-b33b-df91e28d77c2
             //[4] https://www.ibm.com/developerworks/rfe/execute?use_case=viewRfe&CR_ID=71770
             if (supportedCipher.startsWith("SSL_")) {
                 final String tlsPrefixedCipherName = "TLS_" + supportedCipher.substring("SSL_".length());
                 try {
                     engine.setEnabledCipherSuites(new String[]{tlsPrefixedCipherName});
                     SUPPORTED_CIPHERS.add(tlsPrefixedCipherName);
                 } catch (IllegalArgumentException ignored) {
                     // The cipher is not supported ... move on to the next cipher.
                 }
             }
         }
         List<String> ciphers = new ArrayList<String>();
         addIfSupported(SUPPORTED_CIPHERS, ciphers, DEFAULT_CIPHER_SUITES);
         useFallbackCiphersIfDefaultIsEmpty(ciphers, engine.getEnabledCipherSuites());
         DEFAULT_CIPHERS = Collections.unmodifiableList(ciphers);
 
         if (logger.isDebugEnabled()) {
             logger.debug("Default protocols (JDK): {} ", Arrays.asList(DEFAULT_PROTOCOLS));
             logger.debug("Default cipher suites (JDK): {}", DEFAULT_CIPHERS);
         }
     }
 
     private final String[] protocols;
     private final String[] cipherSuites;
     private final List<String> unmodifiableCipherSuites;
     @SuppressWarnings("deprecation")
     private final JdkApplicationProtocolNegotiator apn;
     private final ClientAuth clientAuth;
     private final SSLContext sslContext;
     private final boolean isClient;
 
     /**
      * Creates a new {@link JdkSslContext} from a pre-configured {@link SSLContext}.
      *
      * @param sslContext the {@link SSLContext} to use.
      * @param isClient {@code true} if this context should create {@link SSLEngine}s for client-side usage.
      * @param clientAuth the {@link ClientAuth} to use. This will only be used when {@param isClient} is {@code false}.
      */
     public JdkSslContext(SSLContext sslContext, boolean isClient,
                          ClientAuth clientAuth) {
         this(sslContext, isClient, null, IdentityCipherSuiteFilter.INSTANCE,
                 JdkDefaultApplicationProtocolNegotiator.INSTANCE, clientAuth, null, false);
     }
 
     /**
      * Creates a new {@link JdkSslContext} from a pre-configured {@link SSLContext}.
      *
      * @param sslContext the {@link SSLContext} to use.
      * @param isClient {@code true} if this context should create {@link SSLEngine}s for client-side usage.
      * @param ciphers the ciphers to use or {@code null} if the standard should be used.
      * @param cipherFilter the filter to use.
      * @param apn the {@link ApplicationProtocolConfig} to use.
      * @param clientAuth the {@link ClientAuth} to use. This will only be used when {@param isClient} is {@code false}.
      */
     public JdkSslContext(SSLContext sslContext, boolean isClient, Iterable<String> ciphers,
                          CipherSuiteFilter cipherFilter, ApplicationProtocolConfig apn,
                          ClientAuth clientAuth) {
         this(sslContext, isClient, ciphers, cipherFilter, toNegotiator(apn, !isClient), clientAuth, null, false);
     }
 
     @SuppressWarnings("deprecation")
     JdkSslContext(SSLContext sslContext, boolean isClient, Iterable<String> ciphers, CipherSuiteFilter cipherFilter,
                   JdkApplicationProtocolNegotiator apn, ClientAuth clientAuth, String[] protocols, boolean startTls) {
         super(startTls);
         this.apn = checkNotNull(apn, "apn");
         this.clientAuth = checkNotNull(clientAuth, "clientAuth");
         cipherSuites = checkNotNull(cipherFilter, "cipherFilter").filterCipherSuites(
                 ciphers, DEFAULT_CIPHERS, SUPPORTED_CIPHERS);
         this.protocols = protocols == null ? DEFAULT_PROTOCOLS : protocols;
         unmodifiableCipherSuites = Collections.unmodifiableList(Arrays.asList(cipherSuites));
         this.sslContext = checkNotNull(sslContext, "sslContext");
         this.isClient = isClient;
     }
 
     /**
      * Returns the JDK {@link SSLContext} object held by this context.
      */
     public final SSLContext context() {
         return sslContext;
     }
 
     @Override
     public final boolean isClient() {
         return isClient;
     }
 
     /**
      * Returns the JDK {@link SSLSessionContext} object held by this context.
      */
     @Override
     public final SSLSessionContext sessionContext() {
         if (isServer()) {
             return context().getServerSessionContext();
         } else {
             return context().getClientSessionContext();
         }
     }
 
     @Override
     public final List<String> cipherSuites() {
         return unmodifiableCipherSuites;
     }
 
     @Override
     public final long sessionCacheSize() {
         return sessionContext().getSessionCacheSize();
     }
 
     @Override
     public final long sessionTimeout() {
         return sessionContext().getSessionTimeout();
     }
 
     @Override
     public final SSLEngine newEngine(ByteBufAllocator alloc) {
         return configureAndWrapEngine(context().createSSLEngine(), alloc);
     }
 
     @Override
     public final SSLEngine newEngine(ByteBufAllocator alloc, String peerHost, int peerPort) {
         return configureAndWrapEngine(context().createSSLEngine(peerHost, peerPort), alloc);
     }
 
     @SuppressWarnings("deprecation")
     private SSLEngine configureAndWrapEngine(SSLEngine engine, ByteBufAllocator alloc) {
         engine.setEnabledCipherSuites(cipherSuites);
         engine.setEnabledProtocols(protocols);
         engine.setUseClientMode(isClient());
         if (isServer()) {
             switch (clientAuth) {
                 case OPTIONAL:
                     engine.setWantClientAuth(true);
                     break;
                 case REQUIRE:
                     engine.setNeedClientAuth(true);
                     break;
                 case NONE:
                     break; // exhaustive cases
                 default:
                     throw new Error("Unknown auth " + clientAuth);
             }
         }
         JdkApplicationProtocolNegotiator.SslEngineWrapperFactory factory = apn.wrapperFactory();
         if (factory instanceof JdkApplicationProtocolNegotiator.AllocatorAwareSslEngineWrapperFactory) {
             return ((JdkApplicationProtocolNegotiator.AllocatorAwareSslEngineWrapperFactory) factory)
                     .wrapSslEngine(engine, alloc, apn, isServer());
         }
         return factory.wrapSslEngine(engine, apn, isServer());
     }
 
     @Override
     public final JdkApplicationProtocolNegotiator applicationProtocolNegotiator() {
         return apn;
     }
 
     /**
      * Translate a {@link ApplicationProtocolConfig} object to a {@link JdkApplicationProtocolNegotiator} object.
      * @param config The configuration which defines the translation
      * @param isServer {@code true} if a server {@code false} otherwise.
      * @return The results of the translation
      */
     @SuppressWarnings("deprecation")
     static JdkApplicationProtocolNegotiator toNegotiator(ApplicationProtocolConfig config, boolean isServer) {
         if (config == null) {
             return JdkDefaultApplicationProtocolNegotiator.INSTANCE;
         }
 
         switch(config.protocol()) {
         case NONE:
             return JdkDefaultApplicationProtocolNegotiator.INSTANCE;
         case ALPN:
             if (isServer) {
                 switch(config.selectorFailureBehavior()) {
                 case FATAL_ALERT:
                     return new JdkAlpnApplicationProtocolNegotiator(true, config.supportedProtocols());
                 case NO_ADVERTISE:
                     return new JdkAlpnApplicationProtocolNegotiator(false, config.supportedProtocols());
                 default:
                     throw new UnsupportedOperationException(new StringBuilder("JDK provider does not support ")
                     .append(config.selectorFailureBehavior()).append(" failure behavior").toString());
                 }
             } else {
                 switch(config.selectedListenerFailureBehavior()) {
                 case ACCEPT:
                     return new JdkAlpnApplicationProtocolNegotiator(false, config.supportedProtocols());
                 case FATAL_ALERT:
                     return new JdkAlpnApplicationProtocolNegotiator(true, config.supportedProtocols());
                 default:
                     throw new UnsupportedOperationException(new StringBuilder("JDK provider does not support ")
                     .append(config.selectedListenerFailureBehavior()).append(" failure behavior").toString());
                 }
             }
         case NPN:
             if (isServer) {
                 switch(config.selectedListenerFailureBehavior()) {
                 case ACCEPT:
                     return new JdkNpnApplicationProtocolNegotiator(false, config.supportedProtocols());
                 case FATAL_ALERT:
                     return new JdkNpnApplicationProtocolNegotiator(true, config.supportedProtocols());
                 default:
                     throw new UnsupportedOperationException(new StringBuilder("JDK provider does not support ")
                     .append(config.selectedListenerFailureBehavior()).append(" failure behavior").toString());
                 }
             } else {
                 switch(config.selectorFailureBehavior()) {
                 case FATAL_ALERT:
                     return new JdkNpnApplicationProtocolNegotiator(true, config.supportedProtocols());
                 case NO_ADVERTISE:
                     return new JdkNpnApplicationProtocolNegotiator(false, config.supportedProtocols());
                 default:
                     throw new UnsupportedOperationException(new StringBuilder("JDK provider does not support ")
                     .append(config.selectorFailureBehavior()).append(" failure behavior").toString());
                 }
             }
         default:
             throw new UnsupportedOperationException(new StringBuilder("JDK provider does not support ")
             .append(config.protocol()).append(" protocol").toString());
         }
     }
 
     /**
      * Build a {@link KeyManagerFactory} based upon a key file, key file password, and a certificate chain.
      * @param certChainFile a X.509 certificate chain file in PEM format
      * @param keyFile a PKCS#8 private key file in PEM format
      * @param keyPassword the password of the {@code keyFile}.
      *                    {@code null} if it's not password-protected.
      * @param kmf The existing {@link KeyManagerFactory} that will be used if not {@code null}
      * @return A {@link KeyManagerFactory} based upon a key file, key file password, and a certificate chain.
      * @deprecated will be removed.
      */
     @Deprecated
     protected static KeyManagerFactory buildKeyManagerFactory(File certChainFile, File keyFile, String keyPassword,
             KeyManagerFactory kmf)
                     throws UnrecoverableKeyException, KeyStoreException, NoSuchAlgorithmException,
                     NoSuchPaddingException, InvalidKeySpecException, InvalidAlgorithmParameterException,
                     CertificateException, KeyException, IOException {
         String algorithm = Security.getProperty("ssl.KeyManagerFactory.algorithm");
         if (algorithm == null) {
             algorithm = "SunX509";
         }
         return buildKeyManagerFactory(certChainFile, algorithm, keyFile, keyPassword, kmf);
     }
 
     /**
      * Build a {@link KeyManagerFactory} based upon a key algorithm, key file, key file password,
      * and a certificate chain.
      * @param certChainFile a X.509 certificate chain file in PEM format
      * @param keyAlgorithm the standard name of the requested algorithm. See the Java Secure Socket Extension
      * Reference Guide for information about standard algorithm names.
      * @param keyFile a PKCS#8 private key file in PEM format
      * @param keyPassword the password of the {@code keyFile}.
      *                    {@code null} if it's not password-protected.
      * @param kmf The existing {@link KeyManagerFactory} that will be used if not {@code null}
      * @return A {@link KeyManagerFactory} based upon a key algorithm, key file, key file password,
      * and a certificate chain.
      * @deprecated will be removed.
      */
     @Deprecated
     protected static KeyManagerFactory buildKeyManagerFactory(File certChainFile,
             String keyAlgorithm, File keyFile, String keyPassword, KeyManagerFactory kmf)
                     throws KeyStoreException, NoSuchAlgorithmException, NoSuchPaddingException,
                     InvalidKeySpecException, InvalidAlgorithmParameterException, IOException,
                     CertificateException, KeyException, UnrecoverableKeyException {
         return buildKeyManagerFactory(toX509Certificates(certChainFile), keyAlgorithm,
                                       toPrivateKey(keyFile, keyPassword), keyPassword, kmf);
     }
 }