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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
//
// Receiver side of reliability layer
#ifndef OPENVPN_RELIABLE_RELRECV_H
#define OPENVPN_RELIABLE_RELRECV_H
#include <openvpn/common/size.hpp>
#include <openvpn/common/exception.hpp>
#include <openvpn/common/msgwin.hpp>
#include <openvpn/reliable/relcommon.hpp>
namespace openvpn {
template <typename PACKET>
class ReliableRecvTemplate
{
public:
OPENVPN_SIMPLE_EXCEPTION(rel_next_sequenced_not_ready);
typedef reliable::id_t id_t;
class Message : public ReliableMessageBase<PACKET>
{
friend class ReliableRecvTemplate;
};
ReliableRecvTemplate()
{
}
ReliableRecvTemplate(const id_t span, id_t start_at = 0)
{
init(span, start_at);
}
void init(const id_t span, id_t start_at = 0)
{
window_.init(start_at, span);
}
// Call with unsequenced packet off of the wire.
// Will return receive flags below.
enum
{
ACK_TO_SENDER = (1 << 0), // ACK for this packet should be returned to sender
IN_WINDOW = (1 << 1) // Packet is in-window (otherwise, packet is dropped)
};
unsigned int receive(const PACKET &packet, const id_t id)
{
unsigned int rflags;
if (window_.in_window(id))
{
Message &m = window_.ref_by_id(id);
m.id_ = id;
m.packet = packet;
rflags = ACK_TO_SENDER | IN_WINDOW;
}
else
rflags = window_.pre_window(id) ? ACK_TO_SENDER : 0;
return rflags;
}
// Return true if next_sequenced() is ready to return next message
bool ready() const
{
return window_.head_defined();
}
// Return next message in sequence.
// Requires that ready() returns true.
Message &next_sequenced()
{
return window_.ref_head();
}
// Call after message returned by receive is ready to
// be disposed of.
void advance()
{
window_.rm_head_nocheck();
}
private:
MessageWindow<Message, id_t> window_;
};
} // namespace openvpn
#endif // OPENVPN_RELIABLE_RELRECV_H
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