//
// SecureSocketImpl.h
//
// Library: NetSSL_OpenSSL
// Package: SSLSockets
// Module:  SecureSocketImpl
//
// Definition of the SecureSocketImpl class.
//
// Copyright (c) 2006-2010, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef NetSSL_SecureSocketImpl_INCLUDED
#define NetSSL_SecureSocketImpl_INCLUDED


#include <openssl/bio.h>
#include <openssl/ssl.h>
#include "Poco/Net/Context.h"
#include "Poco/Net/NetSSL.h"
#include "Poco/Net/Session.h"
#include "Poco/Net/SocketImpl.h"
#include "Poco/Net/X509Certificate.h"

#include <mutex>

namespace Poco
{
namespace Net
{


    class HostEntry;


    class NetSSL_API SecureSocketImpl
    /// The SocketImpl for SecureStreamSocket.
    {
    public:
        SecureSocketImpl(Poco::AutoPtr<SocketImpl> pSocketImpl, Context::Ptr pContext);
        /// Creates the SecureSocketImpl using an already
        /// connected stream socket.

        virtual ~SecureSocketImpl();
        /// Destroys the SecureSocketImpl.

        SocketImpl * acceptConnection(SocketAddress & clientAddr);
        /// Get the next completed connection from the
        /// socket's completed connection queue.
        ///
        /// If the queue is empty, waits until a connection
        /// request completes.
        ///
        /// Returns a new SSL socket for the connection
        /// with the client.
        ///
        /// The client socket's address is returned in clientAddr.

        void connect(const SocketAddress & address, bool performHandshake);
        /// Initializes the socket and establishes a secure connection to
        /// the TCP server at the given address.
        ///
        /// If performHandshake is true, the SSL handshake is performed immediately
        /// after establishing the connection. Otherwise, the handshake is performed
        /// the first time sendBytes(), receiveBytes() or completeHandshake() is called.

        void connect(const SocketAddress & address, const Poco::Timespan & timeout, bool performHandshake);
        /// Initializes the socket, sets the socket timeout and
        /// establishes a secure connection to the TCP server at the given address.
        ///
        /// If performHandshake is true, the SSL handshake is performed immediately
        /// after establishing the connection. Otherwise, the handshake is performed
        /// the first time sendBytes(), receiveBytes() or completeHandshake() is called.

        void connectNB(const SocketAddress & address);
        /// Initializes the socket and establishes a secure connection to
        /// the TCP server at the given address. Prior to opening the
        /// connection the socket is set to nonblocking mode.

        void bind(const SocketAddress & address, bool reuseAddress = false, bool reusePort = false);
        /// Bind a local address to the socket.
        ///
        /// This is usually only done when establishing a server
        /// socket. SSL clients should not bind a socket to a
        /// specific address.
        ///
        /// If reuseAddress is true, sets the SO_REUSEADDR
        /// socket option.

        void listen(int backlog = 64);
        /// Puts the socket into listening state.
        ///
        /// The socket becomes a passive socket that
        /// can accept incoming connection requests.
        ///
        /// The backlog argument specifies the maximum
        /// number of connections that can be queued
        /// for this socket.

        void shutdown();
        /// Shuts down the connection by attempting
        /// an orderly SSL shutdown, then actually
        /// shutting down the TCP connection.

        void close();
        /// Close the socket.

        void abort();
        /// Aborts the connection by closing the
        /// underlying TCP connection. No orderly SSL shutdown
        /// is performed.

        int sendBytes(const void * buffer, int length, int flags = 0);
        /// Sends the contents of the given buffer through
        /// the socket. Any specified flags are ignored.
        ///
        /// Returns the number of bytes sent, which may be
        /// less than the number of bytes specified.

        int receiveBytes(void * buffer, int length, int flags = 0);
        /// Receives data from the socket and stores it
        /// in buffer. Up to length bytes are received.
        ///
        /// Returns the number of bytes received.

        int available() const;
        /// Returns the number of bytes available from the
        /// SSL buffer for immediate reading.

        int completeHandshake();
        /// Completes the SSL handshake.
        ///
        /// If the SSL connection was the result of an accept(),
        /// the server-side handshake is completed, otherwise
        /// a client-side handshake is performed.

        poco_socket_t sockfd();
        /// Returns the underlying socket descriptor.

        X509 * peerCertificate() const;
        /// Returns the peer's certificate.

        Context::Ptr context() const;
        /// Returns the SSL context used for this socket.

        void verifyPeerCertificate();
        /// Performs post-connect (or post-accept) peer certificate validation,
        /// using the peer host name set with setPeerHostName(), or the peer's
        /// IP address string if no peer host name has been set.

        void verifyPeerCertificate(const std::string & hostName);
        /// Performs post-connect (or post-accept) peer certificate validation
        /// using the given peer host name.

        void setPeerHostName(const std::string & hostName);
        /// Sets the peer host name for certificate validation purposes.

        const std::string & getPeerHostName() const;
        /// Returns the peer host name.

        Session::Ptr currentSession();
        /// Returns the SSL session of the current connection,
        /// for reuse in a future connection (if session caching
        /// is enabled).
        ///
        /// If no connection is established, returns null.

        void useSession(Session::Ptr pSession);
        /// Sets the SSL session to use for the next
        /// connection. Setting a previously saved Session
        /// object is necessary to enable session caching.
        ///
        /// To remove the currently set session, a null pointer
        /// can be given.
        ///
        /// Must be called before connect() to be effective.

        bool sessionWasReused();
        /// Returns true iff a reused session was negotiated during
        /// the handshake.

        virtual void setBlocking(bool flag);
        /// Sets the socket in blocking mode if flag is true,
        /// disables blocking mode if flag is false.

        virtual bool getBlocking() const;
        /// Returns the blocking mode of the socket.
        /// This method will only work if the blocking modes of
        /// the socket are changed via the setBlocking method!


    protected:
        void acceptSSL();
        /// Assume per-object mutex is locked.
        /// Performs a server-side SSL handshake and certificate verification.

        void connectSSL(bool performHandshake);
        /// Performs a client-side SSL handshake and establishes a secure
        /// connection over an already existing TCP connection.

        long verifyPeerCertificateImpl(const std::string & hostName);
        /// Performs post-connect (or post-accept) peer certificate validation.

        static bool isLocalHost(const std::string & hostName);
        /// Returns true iff the given host name is the local host
        /// (either "localhost" or "127.0.0.1").

        bool mustRetry(int rc, Poco::Timespan & remaining_time);
        /// Returns true if the last operation should be retried,
        /// otherwise false.
        ///
        /// In case of an SSL_ERROR_WANT_READ error, and if the socket is
        /// blocking, waits for the underlying socket to become readable.
        ///
        /// In case of an SSL_ERROR_WANT_WRITE error, and if the socket is
        /// blocking, waits for the underlying socket to become writable.
        ///
        /// Can also throw a Poco::TimeoutException if the socket does
        /// not become readable or writable within the sockets
        /// receive or send timeout.

        int handleError(int rc);
        /// Handles an SSL error by throwing an appropriate exception.

        void reset();
        /// Prepares the socket for re-use.
        ///
        /// After closing and resetting a socket, the socket can
        /// be used for a new connection.
        ///
        /// Note that simply closing a socket is not sufficient
        /// to be able to re-use it again.

        Poco::Timespan getMaxTimeout();

    private:
        SecureSocketImpl(const SecureSocketImpl &);
        SecureSocketImpl & operator=(const SecureSocketImpl &);

        mutable std::recursive_mutex _mutex;
        SSL * _pSSL; // GUARDED_BY _mutex
        Poco::AutoPtr<SocketImpl> _pSocket;
        Context::Ptr _pContext;
        bool _needHandshake;
        std::string _peerHostName;
        Session::Ptr _pSession;

        friend class SecureStreamSocketImpl;
    };


    //
    // inlines
    //
    inline poco_socket_t SecureSocketImpl::sockfd()
    {
        return _pSocket->sockfd();
    }


    inline Context::Ptr SecureSocketImpl::context() const
    {
        return _pContext;
    }


    inline const std::string & SecureSocketImpl::getPeerHostName() const
    {
        return _peerHostName;
    }


}
} // namespace Poco::Net


#endif // NetSSL_SecureSocketImpl_INCLUDED