* The secure communications modes include:
* The cipher suite used is established by a negotiation process called * "handshaking". The goal of this process is to create or rejoin a * "session", which may protect many connections over time. After * handshaking has completed, you can access session attributes by * using the {@link #getSession()} method. *
* The SSLSocket class provides much of the same security
* functionality, but all of the inbound and outbound data is
* automatically transported using the underlying {@link
* java.net.Socket Socket}, which by design uses a blocking model.
* While this is appropriate for many applications, this model does not
* provide the scalability required by large servers.
*
* The primary distinction of an SSLEngine is that it
* operates on inbound and outbound byte streams, independent of the
* transport mechanism. It is the responsibility of the
* SSLEngine user to arrange for reliable I/O transport to
* the peer. By separating the SSL/TLS abstraction from the I/O
* transport mechanism, the SSLEngine can be used for a
* wide variety of I/O types, such as {@link
* java.nio.channels.spi.AbstractSelectableChannel#configureBlocking(boolean)
* non-blocking I/O (polling)}, {@link java.nio.channels.Selector
* selectable non-blocking I/O}, {@link java.net.Socket Socket} and the
* traditional Input/OutputStreams, local {@link java.nio.ByteBuffer
* ByteBuffers} or byte arrays, future asynchronous
* I/O models , and so on.
*
* At a high level, the SSLEngine appears thus:
*
*
* app data * * | ^ * | | | * v | | * +----+-----|-----+----+ * | | | * | SSL|Engine | * wrap() | | | unwrap() * | OUTBOUND | INBOUND | * | | | * +----+-----|-----+----+ * | | ^ * | | | * v | * * net data ** Application data (also known as plaintext or cleartext) is data which * is produced or consumed by an application. Its counterpart is * network data, which consists of either handshaking and/or ciphertext * (encrypted) data, and destined to be transported via an I/O * mechanism. Inbound data is data which has been received from the * peer, and outbound data is destined for the peer. *
* (In the context of an SSLEngine, the term "handshake
* data" is taken to mean any data exchanged to establish and control a
* secure connection. Handshake data includes the SSL/TLS messages
* "alert", "change_cipher_spec," and "handshake.")
*
* There are five distinct phases to an SSLEngine.
*
*
SSLEngine has been created and
* initialized, but has not yet been used. During this phase, an
* application may set any SSLEngine-specific settings
* (enabled cipher suites, whether the SSLEngine should
* handshake in client or server mode, and so on). Once
* handshaking has begun, though, any new settings (except
* client/server mode, see below) will be used for
* the next handshake.
*
* SSLEngine. Outbound
* application messages are encrypted and integrity protected,
* and inbound messages reverse the process.
*
* SSLEngine
* configuration settings will not be used until the next
* handshake.
*
* SSLEngine and should
* send/receive any remaining messages to the peer before
* closing the underlying transport mechanism. Once an engine is
* closed, it is not reusable: a new SSLEngine must
* be created.
* SSLEngine is created by calling {@link
* SSLContext#createSSLEngine()} from an initialized
* SSLContext. Any configuration
* parameters should be set before making the first call to
* wrap(), unwrap(), or
* beginHandshake(). These methods all trigger the
* initial handshake.
*
* Data moves through the engine by calling {@link #wrap(ByteBuffer,
* ByteBuffer) wrap()} or {@link #unwrap(ByteBuffer, ByteBuffer)
* unwrap()} on outbound or inbound data, respectively. Depending on
* the state of the SSLEngine, a wrap() call
* may consume application data from the source buffer and may produce
* network data in the destination buffer. The outbound data
* may contain application and/or handshake data. A call to
* unwrap() will examine the source buffer and may
* advance the handshake if the data is handshaking information, or
* may place application data in the destination buffer if the data
* is application. The state of the underlying SSL/TLS algorithm
* will determine when data is consumed and produced.
*
* Calls to wrap() and unwrap() return an
* SSLEngineResult which indicates the status of the
* operation, and (optionally) how to interact with the engine to make
* progress.
*
* The SSLEngine produces/consumes complete SSL/TLS
* packets only, and does not store application data internally between
* calls to wrap()/unwrap(). Thus input and output
* ByteBuffers must be sized appropriately to hold the
* maximum record that can be produced. Calls to {@link
* SSLSession#getPacketBufferSize()} and {@link
* SSLSession#getApplicationBufferSize()} should be used to determine
* the appropriate buffer sizes. The size of the outbound application
* data buffer generally does not matter. If buffer conditions do not
* allow for the proper consumption/production of data, the application
* must determine (via {@link SSLEngineResult}) and correct the
* problem, and then try the call again.
*
* For example, unwrap() will return a {@link
* SSLEngineResult.Status#BUFFER_OVERFLOW} result if the engine
* determines that there is not enough destination buffer space available.
* Applications should call {@link SSLSession#getApplicationBufferSize()}
* and compare that value with the space available in the destination buffer,
* enlarging the buffer if necessary. Similarly, if unwrap()
* were to return a {@link SSLEngineResult.Status#BUFFER_UNDERFLOW}, the
* application should call {@link SSLSession#getPacketBufferSize()} to ensure
* that the source buffer has enough room to hold a record (enlarging if
* necessary), and then obtain more inbound data.
*
*
{@code
* SSLEngineResult r = engine.unwrap(src, dst);
* switch (r.getStatus()) {
* BUFFER_OVERFLOW:
* // Could attempt to drain the dst buffer of any already obtained
* // data, but we'll just increase it to the size needed.
* int appSize = engine.getSession().getApplicationBufferSize();
* ByteBuffer b = ByteBuffer.allocate(appSize + dst.position());
* dst.flip();
* b.put(dst);
* dst = b;
* // retry the operation.
* break;
* BUFFER_UNDERFLOW:
* int netSize = engine.getSession().getPacketBufferSize();
* // Resize buffer if needed.
* if (netSize > dst.capacity()) {
* ByteBuffer b = ByteBuffer.allocate(netSize);
* src.flip();
* b.put(src);
* src = b;
* }
* // Obtain more inbound network data for src,
* // then retry the operation.
* break;
* // other cases: CLOSED, OK.
* }
* }
*
*
* Unlike SSLSocket, all methods of SSLEngine are
* non-blocking. SSLEngine implementations may
* require the results of tasks that may take an extended period of
* time to complete, or may even block. For example, a TrustManager
* may need to connect to a remote certificate validation service,
* or a KeyManager might need to prompt a user to determine which
* certificate to use as part of client authentication. Additionally,
* creating cryptographic signatures and verifying them can be slow,
* seemingly blocking.
*
* For any operation which may potentially block, the
* SSLEngine will create a {@link java.lang.Runnable}
* delegated task. When SSLEngineResult indicates that a
* delegated task result is needed, the application must call {@link
* #getDelegatedTask()} to obtain an outstanding delegated task and
* call its {@link java.lang.Runnable#run() run()} method (possibly using
* a different thread depending on the compute strategy). The
* application should continue obtaining delegated tasks until no more
* exist, and try the original operation again.
*
* At the end of a communication session, applications should properly
* close the SSL/TLS link. The SSL/TLS protocols have closure handshake
* messages, and these messages should be communicated to the peer
* before releasing the SSLEngine and closing the
* underlying transport mechanism. A close can be initiated by one of:
* an SSLException, an inbound closure handshake message, or one of the
* close methods. In all cases, closure handshake messages are
* generated by the engine, and wrap() should be repeatedly
* called until the resulting SSLEngineResult's status
* returns "CLOSED", or {@link #isOutboundDone()} returns true. All
* data obtained from the wrap() method should be sent to the
* peer.
*
* {@link #closeOutbound()} is used to signal the engine that the * application will not be sending any more data. *
* A peer will signal its intent to close by sending its own closure
* handshake message. After this message has been received and
* processed by the local SSLEngine's unwrap()
* call, the application can detect the close by calling
* unwrap() and looking for a SSLEngineResult
* with status "CLOSED", or if {@link #isInboundDone()} returns true.
* If for some reason the peer closes the communication link without
* sending the proper SSL/TLS closure message, the application can
* detect the end-of-stream and can signal the engine via {@link
* #closeInbound()} that there will no more inbound messages to
* process. Some applications might choose to require orderly shutdown
* messages from a peer, in which case they can check that the closure
* was generated by a handshake message and not by an end-of-stream
* condition.
*
* There are two groups of cipher suites which you will need to know * about when managing cipher suites: * *
* Each SSL/TLS connection must have one client and one server, thus
* each endpoint must decide which role to assume. This choice determines
* who begins the handshaking process as well as which type of messages
* should be sent by each party. The method {@link
* #setUseClientMode(boolean)} configures the mode. Once the initial
* handshaking has started, an SSLEngine can not switch
* between client and server modes, even when performing renegotiations.
*
* Applications might choose to process delegated tasks in different
* threads. When an SSLEngine
* is created, the current {@link java.security.AccessControlContext}
* is saved. All future delegated tasks will be processed using this
* context: that is, all access control decisions will be made using the
* context captured at engine creation.
*
*
wrap() and unwrap() methods
* may execute concurrently of each other.
*
* * For example: * *
* synchronized (outboundLock) {
* sslEngine.wrap(src, dst);
* outboundQueue.put(dst);
* }
*
*
* As a corollary, two threads must not attempt to call the same method
* (either wrap() or unwrap()) concurrently,
* because there is no way to guarantee the eventual packet ordering.
* SSLEngine providing no hints
* for an internal session reuse strategy.
*
* @see SSLContext#createSSLEngine()
* @see SSLSessionContext
*/
protected SSLEngine() {
}
/**
* Constructor for an SSLEngine.
*
* SSLEngine implementations may use the
* peerHost and peerPort parameters as hints
* for their internal session reuse strategy.
*
* Some cipher suites (such as Kerberos) require remote hostname * information. Implementations of this class should use this * constructor to use Kerberos. *
* The parameters are not authenticated by the
* SSLEngine.
*
* @param peerHost the name of the peer host
* @param peerPort the port number of the peer
* @see SSLContext#createSSLEngine(String, int)
* @see SSLSessionContext
*/
protected SSLEngine(String peerHost, int peerPort) {
this.peerHost = peerHost;
this.peerPort = peerPort;
}
/**
* Returns the host name of the peer.
*
* Note that the value is not authenticated, and should not be * relied upon. * * @return the host name of the peer, or null if nothing is * available. */ public String getPeerHost() { return peerHost; } /** * Returns the port number of the peer. *
* Note that the value is not authenticated, and should not be * relied upon. * * @return the port number of the peer, or -1 if nothing is * available. */ public int getPeerPort() { return peerPort; } /** * Attempts to encode a buffer of plaintext application data into * SSL/TLS network data. *
* An invocation of this method behaves in exactly the same manner * as the invocation: *
* {@link #wrap(ByteBuffer [], int, int, ByteBuffer)
* engine.wrap(new ByteBuffer [] { src }, 0, 1, dst);}
* ByteBuffer containing outbound application data
* @param dst
* a ByteBuffer to hold outbound network data
* @return an SSLEngineResult describing the result
* of this operation.
* @throws SSLException
* A problem was encountered while processing the
* data that caused the SSLEngine to abort.
* See the class description for more information on
* engine closure.
* @throws ReadOnlyBufferException
* if the dst buffer is read-only.
* @throws IllegalArgumentException
* if either src or dst
* is null.
* @throws IllegalStateException if the client/server mode
* has not yet been set.
* @see #wrap(ByteBuffer [], int, int, ByteBuffer)
*/
public SSLEngineResult wrap(ByteBuffer src,
ByteBuffer dst) throws SSLException {
return wrap(new ByteBuffer [] { src }, 0, 1, dst);
}
/**
* Attempts to encode plaintext bytes from a sequence of data
* buffers into SSL/TLS network data.
* * An invocation of this method behaves in exactly the same manner * as the invocation: *
* {@link #wrap(ByteBuffer [], int, int, ByteBuffer)
* engine.wrap(srcs, 0, srcs.length, dst);}
* ByteBuffers containing the
* outbound application data
* @param dst
* a ByteBuffer to hold outbound network data
* @return an SSLEngineResult describing the result
* of this operation.
* @throws SSLException
* A problem was encountered while processing the
* data that caused the SSLEngine to abort.
* See the class description for more information on
* engine closure.
* @throws ReadOnlyBufferException
* if the dst buffer is read-only.
* @throws IllegalArgumentException
* if either srcs or dst
* is null, or if any element in srcs is null.
* @throws IllegalStateException if the client/server mode
* has not yet been set.
* @see #wrap(ByteBuffer [], int, int, ByteBuffer)
*/
public SSLEngineResult wrap(ByteBuffer [] srcs,
ByteBuffer dst) throws SSLException {
if (srcs == null) {
throw new IllegalArgumentException("src == null");
}
return wrap(srcs, 0, srcs.length, dst);
}
/**
* Attempts to encode plaintext bytes from a subsequence of data
* buffers into SSL/TLS network data. This "gathering"
* operation encodes, in a single invocation, a sequence of bytes
* from one or more of a given sequence of buffers. Gathering
* wraps are often useful when implementing network protocols or
* file formats that, for example, group data into segments
* consisting of one or more fixed-length headers followed by a
* variable-length body. See
* {@link java.nio.channels.GatheringByteChannel} for more
* information on gathering, and {@link
* java.nio.channels.GatheringByteChannel#write(ByteBuffer[],
* int, int)} for more information on the subsequence
* behavior.
* * Depending on the state of the SSLEngine, this method may produce * network data without consuming any application data (for example, * it may generate handshake data.) *
* The application is responsible for reliably transporting the * network data to the peer, and for ensuring that data created by * multiple calls to wrap() is transported in the same order in which * it was generated. The application must properly synchronize * multiple calls to this method. *
* If this SSLEngine has not yet started its initial
* handshake, this method will automatically start the handshake.
*
* This method will attempt to produce SSL/TLS records, and will
* consume as much source data as possible, but will never consume
* more than the sum of the bytes remaining in each buffer. Each
* ByteBuffer's position is updated to reflect the
* amount of data consumed or produced. The limits remain the
* same.
*
* The underlying memory used by the srcs and
* dst ByteBuffers must not be the same.
*
* See the class description for more information on engine closure.
*
* @param srcs
* an array of ByteBuffers containing the
* outbound application data
* @param offset
* The offset within the buffer array of the first buffer from
* which bytes are to be retrieved; it must be non-negative
* and no larger than srcs.length
* @param length
* The maximum number of buffers to be accessed; it must be
* non-negative and no larger than
* srcs.length - offset
* @param dst
* a ByteBuffer to hold outbound network data
* @return an SSLEngineResult describing the result
* of this operation.
* @throws SSLException
* A problem was encountered while processing the
* data that caused the SSLEngine to abort.
* See the class description for more information on
* engine closure.
* @throws IndexOutOfBoundsException
* if the preconditions on the offset and
* length parameters do not hold.
* @throws ReadOnlyBufferException
* if the dst buffer is read-only.
* @throws IllegalArgumentException
* if either srcs or dst
* is null, or if any element in the srcs
* subsequence specified is null.
* @throws IllegalStateException if the client/server mode
* has not yet been set.
* @see java.nio.channels.GatheringByteChannel
* @see java.nio.channels.GatheringByteChannel#write(
* ByteBuffer[], int, int)
*/
public abstract SSLEngineResult wrap(ByteBuffer [] srcs, int offset,
int length, ByteBuffer dst) throws SSLException;
/**
* Attempts to decode SSL/TLS network data into a plaintext
* application data buffer.
*
* An invocation of this method behaves in exactly the same manner * as the invocation: *
* {@link #unwrap(ByteBuffer, ByteBuffer [], int, int)
* engine.unwrap(src, new ByteBuffer [] { dst }, 0, 1);}
* ByteBuffer containing inbound network data.
* @param dst
* a ByteBuffer to hold inbound application data.
* @return an SSLEngineResult describing the result
* of this operation.
* @throws SSLException
* A problem was encountered while processing the
* data that caused the SSLEngine to abort.
* See the class description for more information on
* engine closure.
* @throws ReadOnlyBufferException
* if the dst buffer is read-only.
* @throws IllegalArgumentException
* if either src or dst
* is null.
* @throws IllegalStateException if the client/server mode
* has not yet been set.
* @see #unwrap(ByteBuffer, ByteBuffer [], int, int)
*/
public SSLEngineResult unwrap(ByteBuffer src,
ByteBuffer dst) throws SSLException {
return unwrap(src, new ByteBuffer [] { dst }, 0, 1);
}
/**
* Attempts to decode SSL/TLS network data into a sequence of plaintext
* application data buffers.
* * An invocation of this method behaves in exactly the same manner * as the invocation: *
* {@link #unwrap(ByteBuffer, ByteBuffer [], int, int)
* engine.unwrap(src, dsts, 0, dsts.length);}
* ByteBuffer containing inbound network data.
* @param dsts
* an array of ByteBuffers to hold inbound
* application data.
* @return an SSLEngineResult describing the result
* of this operation.
* @throws SSLException
* A problem was encountered while processing the
* data that caused the SSLEngine to abort.
* See the class description for more information on
* engine closure.
* @throws ReadOnlyBufferException
* if any of the dst buffers are read-only.
* @throws IllegalArgumentException
* if either src or dsts
* is null, or if any element in dsts is null.
* @throws IllegalStateException if the client/server mode
* has not yet been set.
* @see #unwrap(ByteBuffer, ByteBuffer [], int, int)
*/
public SSLEngineResult unwrap(ByteBuffer src,
ByteBuffer [] dsts) throws SSLException {
if (dsts == null) {
throw new IllegalArgumentException("dsts == null");
}
return unwrap(src, dsts, 0, dsts.length);
}
/**
* Attempts to decode SSL/TLS network data into a subsequence of
* plaintext application data buffers. This "scattering"
* operation decodes, in a single invocation, a sequence of bytes
* into one or more of a given sequence of buffers. Scattering
* unwraps are often useful when implementing network protocols or
* file formats that, for example, group data into segments
* consisting of one or more fixed-length headers followed by a
* variable-length body. See
* {@link java.nio.channels.ScatteringByteChannel} for more
* information on scattering, and {@link
* java.nio.channels.ScatteringByteChannel#read(ByteBuffer[],
* int, int)} for more information on the subsequence
* behavior.
* * Depending on the state of the SSLEngine, this method may consume * network data without producing any application data (for example, * it may consume handshake data.) *
* The application is responsible for reliably obtaining the network * data from the peer, and for invoking unwrap() on the data in the * order it was received. The application must properly synchronize * multiple calls to this method. *
* If this SSLEngine has not yet started its initial
* handshake, this method will automatically start the handshake.
*
* This method will attempt to consume one complete SSL/TLS network
* packet, but will never consume more than the sum of the bytes
* remaining in the buffers. Each ByteBuffer's
* position is updated to reflect the amount of data consumed or
* produced. The limits remain the same.
*
* The underlying memory used by the src and
* dsts ByteBuffers must not be the same.
*
* The inbound network buffer may be modified as a result of this * call: therefore if the network data packet is required for some * secondary purpose, the data should be duplicated before calling this * method. Note: the network data will not be useful to a second * SSLEngine, as each SSLEngine contains unique random state which * influences the SSL/TLS messages. *
* See the class description for more information on engine closure.
*
* @param src
* a ByteBuffer containing inbound network data.
* @param dsts
* an array of ByteBuffers to hold inbound
* application data.
* @param offset
* The offset within the buffer array of the first buffer from
* which bytes are to be transferred; it must be non-negative
* and no larger than dsts.length.
* @param length
* The maximum number of buffers to be accessed; it must be
* non-negative and no larger than
* dsts.length - offset.
* @return an SSLEngineResult describing the result
* of this operation.
* @throws SSLException
* A problem was encountered while processing the
* data that caused the SSLEngine to abort.
* See the class description for more information on
* engine closure.
* @throws IndexOutOfBoundsException
* If the preconditions on the offset and
* length parameters do not hold.
* @throws ReadOnlyBufferException
* if any of the dst buffers are read-only.
* @throws IllegalArgumentException
* if either src or dsts
* is null, or if any element in the dsts
* subsequence specified is null.
* @throws IllegalStateException if the client/server mode
* has not yet been set.
* @see java.nio.channels.ScatteringByteChannel
* @see java.nio.channels.ScatteringByteChannel#read(
* ByteBuffer[], int, int)
*/
public abstract SSLEngineResult unwrap(ByteBuffer src,
ByteBuffer [] dsts, int offset, int length) throws SSLException;
/**
* Returns a delegated Runnable task for
* this SSLEngine.
*
* SSLEngine operations may require the results of
* operations that block, or may take an extended period of time to
* complete. This method is used to obtain an outstanding {@link
* java.lang.Runnable} operation (task). Each task must be assigned
* a thread (possibly the current) to perform the {@link
* java.lang.Runnable#run() run} operation. Once the
* run method returns, the Runnable object
* is no longer needed and may be discarded.
*
* Delegated tasks run in the AccessControlContext
* in place when this object was created.
*
* A call to this method will return each outstanding task * exactly once. *
* Multiple delegated tasks can be run in parallel.
*
* @return a delegated Runnable task, or null
* if none are available.
*/
public abstract Runnable getDelegatedTask();
/**
* Signals that no more inbound network data will be sent
* to this SSLEngine.
*
* If the application initiated the closing process by calling * {@link #closeOutbound()}, under some circumstances it is not * required that the initiator wait for the peer's corresponding * close message. (See section 7.2.1 of the TLS specification (RFC 2246) for more * information on waiting for closure alerts.) In such cases, this * method need not be called. *
* But if the application did not initiate the closure process, or * if the circumstances above do not apply, this method should be * called whenever the end of the SSL/TLS data stream is reached. * This ensures closure of the inbound side, and checks that the * peer followed the SSL/TLS close procedure properly, thus * detecting possible truncation attacks. *
* This method is idempotent: if the inbound side has already * been closed, this method does not do anything. *
* {@link #wrap(ByteBuffer, ByteBuffer) wrap()} should be
* called to flush any remaining handshake data.
*
* @throws SSLException
* if this engine has not received the proper SSL/TLS close
* notification message from the peer.
*
* @see #isInboundDone()
* @see #isOutboundDone()
*/
public abstract void closeInbound() throws SSLException;
/**
* Returns whether {@link #unwrap(ByteBuffer, ByteBuffer)} will
* accept any more inbound data messages.
*
* @return true if the SSLEngine will not
* consume anymore network data (and by implication,
* will not produce any more application data.)
* @see #closeInbound()
*/
public abstract boolean isInboundDone();
/**
* Signals that no more outbound application data will be sent
* on this SSLEngine.
*
* This method is idempotent: if the outbound side has already * been closed, this method does not do anything. *
* {@link #wrap(ByteBuffer, ByteBuffer)} should be * called to flush any remaining handshake data. * * @see #isOutboundDone() */ public abstract void closeOutbound(); /** * Returns whether {@link #wrap(ByteBuffer, ByteBuffer)} will * produce any more outbound data messages. *
* Note that during the closure phase, a SSLEngine may
* generate handshake closure data that must be sent to the peer.
* wrap() must be called to generate this data. When
* this method returns true, no more outbound data will be created.
*
* @return true if the SSLEngine will not produce
* any more network data
*
* @see #closeOutbound()
* @see #closeInbound()
*/
public abstract boolean isOutboundDone();
/**
* Returns the names of the cipher suites which could be enabled for use
* on this engine. Normally, only a subset of these will actually
* be enabled by default, since this list may include cipher suites which
* do not meet quality of service requirements for those defaults. Such
* cipher suites might be useful in specialized applications.
*
* @return an array of cipher suite names
* @see #getEnabledCipherSuites()
* @see #setEnabledCipherSuites(String [])
*/
public abstract String [] getSupportedCipherSuites();
/**
* Returns the names of the SSL cipher suites which are currently
* enabled for use on this engine. When an SSLEngine is first
* created, all enabled cipher suites support a minimum quality of
* service. Thus, in some environments this value might be empty.
*
* Even if a suite has been enabled, it might never be used. (For * example, the peer does not support it, the requisite * certificates/private keys for the suite are not available, or an * anonymous suite is enabled but authentication is required.) * * @return an array of cipher suite names * @see #getSupportedCipherSuites() * @see #setEnabledCipherSuites(String []) */ public abstract String [] getEnabledCipherSuites(); /** * Sets the cipher suites enabled for use on this engine. *
* Each cipher suite in the suites parameter must have
* been listed by getSupportedCipherSuites(), or the method will
* fail. Following a successful call to this method, only suites
* listed in the suites parameter are enabled for use.
*
* See {@link #getEnabledCipherSuites()} for more information
* on why a specific cipher suite may never be used on a engine.
*
* @param suites Names of all the cipher suites to enable
* @throws IllegalArgumentException when one or more of the ciphers
* named by the parameter is not supported, or when the
* parameter is null.
* @see #getSupportedCipherSuites()
* @see #getEnabledCipherSuites()
*/
public abstract void setEnabledCipherSuites(String suites []);
/**
* Returns the names of the protocols which could be enabled for use
* with this SSLEngine.
*
* @return an array of protocols supported
*/
public abstract String [] getSupportedProtocols();
/**
* Returns the names of the protocol versions which are currently
* enabled for use with this SSLEngine.
*
* @return an array of protocols
* @see #setEnabledProtocols(String [])
*/
public abstract String [] getEnabledProtocols();
/**
* Set the protocol versions enabled for use on this engine.
*
* The protocols must have been listed by getSupportedProtocols()
* as being supported. Following a successful call to this method,
* only protocols listed in the protocols parameter
* are enabled for use.
*
* @param protocols Names of all the protocols to enable.
* @throws IllegalArgumentException when one or more of
* the protocols named by the parameter is not supported or
* when the protocols parameter is null.
* @see #getEnabledProtocols()
*/
public abstract void setEnabledProtocols(String protocols[]);
/**
* Returns the SSLSession in use in this
* SSLEngine.
*
* These can be long lived, and frequently correspond to an entire * login session for some user. The session specifies a particular * cipher suite which is being actively used by all connections in * that session, as well as the identities of the session's client * and server. *
* Unlike {@link SSLSocket#getSession()} * this method does not block until handshaking is complete. *
* Until the initial handshake has completed, this method returns
* a session object which reports an invalid cipher suite of
* "SSL_NULL_WITH_NULL_NULL".
*
* @return the SSLSession for this SSLEngine
* @see SSLSession
*/
public abstract SSLSession getSession();
/**
* Returns the {@code SSLSession} being constructed during a SSL/TLS
* handshake.
*
* TLS protocols may negotiate parameters that are needed when using * an instance of this class, but before the {@code SSLSession} has * been completely initialized and made available via {@code getSession}. * For example, the list of valid signature algorithms may restrict * the type of certificates that can used during TrustManager * decisions, or the maximum TLS fragment packet sizes can be * resized to better support the network environment. *
* This method provides early access to the {@code SSLSession} being * constructed. Depending on how far the handshake has progressed, * some data may not yet be available for use. For example, if a * remote server will be sending a Certificate chain, but that chain * has yet not been processed, the {@code getPeerCertificates} * method of {@code SSLSession} will throw a * SSLPeerUnverifiedException. Once that chain has been processed, * {@code getPeerCertificates} will return the proper value. * * @see SSLSocket * @see SSLSession * @see ExtendedSSLSession * @see X509ExtendedKeyManager * @see X509ExtendedTrustManager * * @return null if this instance is not currently handshaking, or * if the current handshake has not progressed far enough to * create a basic SSLSession. Otherwise, this method returns the * {@code SSLSession} currently being negotiated. * @throws UnsupportedOperationException if the underlying provider * does not implement the operation. * * @since 1.7 */ public SSLSession getHandshakeSession() { throw new UnsupportedOperationException(); } /** * Initiates handshaking (initial or renegotiation) on this SSLEngine. *
* This method is not needed for the initial handshake, as the
* wrap() and unwrap() methods will
* implicitly call this method if handshaking has not already begun.
*
* Note that the peer may also request a session renegotiation with
* this SSLEngine by sending the appropriate
* session renegotiate handshake message.
*
* Unlike the {@link SSLSocket#startHandshake() * SSLSocket#startHandshake()} method, this method does not block * until handshaking is completed. *
* To force a complete SSL/TLS session renegotiation, the current * session should be invalidated prior to calling this method. *
* Some protocols may not support multiple handshakes on an existing
* engine and may throw an SSLException.
*
* @throws SSLException
* if a problem was encountered while signaling the
* SSLEngine to begin a new handshake.
* See the class description for more information on
* engine closure.
* @throws IllegalStateException if the client/server mode
* has not yet been set.
* @see SSLSession#invalidate()
*/
public abstract void beginHandshake() throws SSLException;
/**
* Returns the current handshake status for this SSLEngine.
*
* @return the current SSLEngineResult.HandshakeStatus.
*/
public abstract SSLEngineResult.HandshakeStatus getHandshakeStatus();
/**
* Configures the engine to use client (or server) mode when
* handshaking.
*
* This method must be called before any handshaking occurs. * Once handshaking has begun, the mode can not be reset for the * life of this engine. *
* Servers normally authenticate themselves, and clients * are not required to do so. * * @param mode true if the engine should start its handshaking * in "client" mode * @throws IllegalArgumentException if a mode change is attempted * after the initial handshake has begun. * @see #getUseClientMode() */ public abstract void setUseClientMode(boolean mode); /** * Returns true if the engine is set to use client mode when * handshaking. * * @return true if the engine should do handshaking * in "client" mode * @see #setUseClientMode(boolean) */ public abstract boolean getUseClientMode(); /** * Configures the engine to require client authentication. This * option is only useful for engines in the server mode. *
* An engine's client authentication setting is one of the following: *
* Unlike {@link #setWantClientAuth(boolean)}, if this option is set and * the client chooses not to provide authentication information * about itself, the negotiations will stop and the engine will * begin its closure procedure. *
* Calling this method overrides any previous setting made by * this method or {@link #setWantClientAuth(boolean)}. * * @param need set to true if client authentication is required, * or false if no client authentication is desired. * @see #getNeedClientAuth() * @see #setWantClientAuth(boolean) * @see #getWantClientAuth() * @see #setUseClientMode(boolean) */ public abstract void setNeedClientAuth(boolean need); /** * Returns true if the engine will require client authentication. * This option is only useful to engines in the server mode. * * @return true if client authentication is required, * or false if no client authentication is desired. * @see #setNeedClientAuth(boolean) * @see #setWantClientAuth(boolean) * @see #getWantClientAuth() * @see #setUseClientMode(boolean) */ public abstract boolean getNeedClientAuth(); /** * Configures the engine to request client authentication. * This option is only useful for engines in the server mode. *
* An engine's client authentication setting is one of the following: *
* Unlike {@link #setNeedClientAuth(boolean)}, if this option is set and * the client chooses not to provide authentication information * about itself, the negotiations will continue. *
* Calling this method overrides any previous setting made by * this method or {@link #setNeedClientAuth(boolean)}. * * @param want set to true if client authentication is requested, * or false if no client authentication is desired. * @see #getWantClientAuth() * @see #setNeedClientAuth(boolean) * @see #getNeedClientAuth() * @see #setUseClientMode(boolean) */ public abstract void setWantClientAuth(boolean want); /** * Returns true if the engine will request client authentication. * This option is only useful for engines in the server mode. * * @return true if client authentication is requested, * or false if no client authentication is desired. * @see #setNeedClientAuth(boolean) * @see #getNeedClientAuth() * @see #setWantClientAuth(boolean) * @see #setUseClientMode(boolean) */ public abstract boolean getWantClientAuth(); /** * Controls whether new SSL sessions may be established by this engine. * If session creations are not allowed, and there are no * existing sessions to resume, there will be no successful * handshaking. * * @param flag true indicates that sessions may be created; this * is the default. false indicates that an existing session * must be resumed * @see #getEnableSessionCreation() */ public abstract void setEnableSessionCreation(boolean flag); /** * Returns true if new SSL sessions may be established by this engine. * * @return true indicates that sessions may be created; this * is the default. false indicates that an existing session * must be resumed * @see #setEnableSessionCreation(boolean) */ public abstract boolean getEnableSessionCreation(); /** * Returns the SSLParameters in effect for this SSLEngine. * The ciphersuites and protocols of the returned SSLParameters * are always non-null. * * @return the SSLParameters in effect for this SSLEngine. * @since 1.6 */ public SSLParameters getSSLParameters() { SSLParameters params = new SSLParameters(); params.setCipherSuites(getEnabledCipherSuites()); params.setProtocols(getEnabledProtocols()); if (getNeedClientAuth()) { params.setNeedClientAuth(true); } else if (getWantClientAuth()) { params.setWantClientAuth(true); } return params; } /** * Applies SSLParameters to this engine. * *
This means: *
* If supported by the underlying SSL/TLS/DTLS implementation, * application name negotiation mechanisms such as RFC 7301 , the * Application-Layer Protocol Negotiation (ALPN), can negotiate * application-level values between peers. * * @implSpec * The implementation in this class throws * {@code UnsupportedOperationException} and performs no other action. * * @return null if it has not yet been determined if application * protocols might be used for this connection, an empty * {@code String} if application protocols values will not * be used, or a non-empty application protocol {@code String} * if a value was successfully negotiated. * @throws UnsupportedOperationException if the underlying provider * does not implement the operation. * @since 8 */ public String getApplicationProtocol() { throw new UnsupportedOperationException(); } /** * Returns the application protocol value negotiated on a SSL/TLS * handshake currently in progress. *
* Like {@link #getHandshakeSession()}, * a connection may be in the middle of a handshake. The * application protocol may or may not yet be available. * * @implSpec * The implementation in this class throws * {@code UnsupportedOperationException} and performs no other action. * * @return null if it has not yet been determined if application * protocols might be used for this handshake, an empty * {@code String} if application protocols values will not * be used, or a non-empty application protocol {@code String} * if a value was successfully negotiated. * @throws UnsupportedOperationException if the underlying provider * does not implement the operation. * @since 8 */ public String getHandshakeApplicationProtocol() { throw new UnsupportedOperationException(); } /** * Registers a callback function that selects an application protocol * value for a SSL/TLS/DTLS handshake. * The function overrides any values supplied using * {@link SSLParameters#setApplicationProtocols * SSLParameters.setApplicationProtocols} and it supports the following * type parameters: *
** * For example, the following call registers a callback function that * examines the TLS handshake parameters and selects an application protocol * name: **
*- {@code SSLEngine} *
- The function's first argument allows the current {@code SSLEngine} * to be inspected, including the handshake session and configuration * settings. *
- {@code List
} * - The function's second argument lists the application protocol names * advertised by the TLS peer. *
- {@code String} *
- The function's result is an application protocol name, or null to * indicate that none of the advertised names are acceptable. * If the return value is an empty {@code String} then application * protocol indications will not be used. * If the return value is null (no value chosen) or is a value that * was not advertised by the peer, the underlying protocol will * determine what action to take. (For example, ALPN will send a * "no_application_protocol" alert and terminate the connection.) *
{@code
* serverEngine.setHandshakeApplicationProtocolSelector(
* (serverEngine, clientProtocols) -> {
* SSLSession session = serverEngine.getHandshakeSession();
* return chooseApplicationProtocol(
* serverEngine,
* clientProtocols,
* session.getProtocol(),
* session.getCipherSuite());
* });
* }
*
* @apiNote
* This method should be called by TLS server applications before the TLS
* handshake begins. Also, this {@code SSLEngine} should be configured with
* parameters that are compatible with the application protocol selected by
* the callback function. For example, enabling a poor choice of cipher
* suites could result in no suitable application protocol.
* See {@link SSLParameters}.
*
* @implSpec
* The implementation in this class throws
* {@code UnsupportedOperationException} and performs no other action.
*
* @param selector the callback function, or null to disable the callback
* functionality.
* @throws UnsupportedOperationException if the underlying provider
* does not implement the operation.
* @since 8
*/
public void setHandshakeApplicationProtocolSelector(
BiFunction