tcplink.hpp

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//    OpenVPN -- An application to securely tunnel IP networks
//               over a single port, with support for SSL/TLS-based
//               session authentication and key exchange,
//               packet encryption, packet authentication, and
//               packet compression.
//
//    Copyright (C) 2012- OpenVPN Inc.
//
//    SPDX-License-Identifier: MPL-2.0 OR AGPL-3.0-only WITH openvpn3-openssl-exception
//
 
// Low-level TCP transport object.
 
#ifndef OPENVPN_TRANSPORT_TCPLINK_H
#define OPENVPN_TRANSPORT_TCPLINK_H
 
#include <deque>
#include <utility> // for std::move
#include <memory>
 
#include <openvpn/io/io.hpp>
 
#include <openvpn/common/bigmutex.hpp>
#include <openvpn/common/size.hpp>
#include <openvpn/common/rc.hpp>
#include <openvpn/common/socktypes.hpp>
#include <openvpn/frame/frame.hpp>
#include <openvpn/log/sessionstats.hpp>
#include <openvpn/transport/pktstream.hpp>
#include <openvpn/transport/mutate.hpp>
#include <openvpn/transport/tcplinkcommon.hpp>
 
#ifdef OPENVPN_GREMLIN
#include <openvpn/transport/gremlin.hpp>
#endif
 
namespace openvpn::TCPTransport {
 
template <typename Protocol, typename ReadHandler, bool RAW_MODE_ONLY>
class TCPLink : public LinkCommon<Protocol,
                                  ReadHandler,
                                  RAW_MODE_ONLY>
{
    using Queue = std::deque<BufferPtr>;
 
  public:
    using Base = LinkCommon<Protocol,
                            ReadHandler,
                            RAW_MODE_ONLY>;
    using Ptr = RCPtr<TCPLink>;
 
    using protocol = Protocol;
 
    friend Base;
 
    TCPLink(ReadHandler read_handler_arg,
            typename Protocol::socket &socket_arg,
            const size_t send_queue_max_size_arg, // 0 to disable
            const size_t free_list_max_size_arg,
            const Frame::Context &frame_context_arg,
            const SessionStats::Ptr &stats_arg)
        : Base(read_handler_arg,
               socket_arg,
               send_queue_max_size_arg,
               free_list_max_size_arg,
               frame_context_arg,
               stats_arg)
    {
    }
 
  private:
    // Called by LinkCommon
    void from_app_send_buffer(BufferPtr &buf) override
    {
        Base::queue_send_buffer(buf);
    }
 
    void recv_buffer(PacketFrom::SPtr &pfp, const size_t bytes_recvd) override
    {
        bool requeue = true;
        OPENVPN_LOG_TCPLINK_VERBOSE("TCP recv raw="
                                    << Base::raw_mode_read << " size=" << bytes_recvd);
 
        pfp->buf.set_size(bytes_recvd);
        requeue = Base::process_recv_buffer(pfp->buf);
        if (!Base::halt && requeue)
            Base::queue_recv(pfp.release()); // reuse PacketFrom object
    }
};
} // namespace openvpn::TCPTransport
 
#endif