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// Copyright (c) 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef QUICHE_QUIC_TEST_TOOLS_SIMULATOR_PACKET_FILTER_H_
#define QUICHE_QUIC_TEST_TOOLS_SIMULATOR_PACKET_FILTER_H_
#include "net/third_party/quiche/src/quic/test_tools/simulator/port.h"
namespace quic {
namespace simulator {
// Packet filter allows subclasses to filter out the packets that enter the
// input port and exit the output port. Packets in the other direction are
// always passed through.
//
// The filter wraps around the input endpoint, and exposes the resulting
// filtered endpoint via the output() method. For example, if initially there
// are two endpoints, A and B, connected via a symmetric link:
//
// QuicEndpoint endpoint_a;
// QuicEndpoint endpoint_b;
//
// [...]
//
// SymmetricLink a_b_link(&endpoint_a, &endpoint_b, ...);
//
// and the goal is to filter the traffic from A to B, then the new invocation
// would be as follows:
//
// PacketFilter filter(&simulator, "A-to-B packet filter", endpoint_a);
// SymmetricLink a_b_link(&filter, &endpoint_b, ...);
//
// Note that the filter drops the packet instanteneously, without it ever
// reaching the output wire. This means that in a direct endpoint-to-endpoint
// scenario, whenever the packet is dropped, the link would become immediately
// available for the next packet.
class PacketFilter : public Endpoint, public ConstrainedPortInterface {
public:
// Initialize the filter by wrapping around |input|. Does not take the
// ownership of |input|.
PacketFilter(Simulator* simulator, std::string name, Endpoint* input);
PacketFilter(const PacketFilter&) = delete;
PacketFilter& operator=(const PacketFilter&) = delete;
~PacketFilter() override;
// Implementation of ConstrainedPortInterface.
void AcceptPacket(std::unique_ptr<Packet> packet) override;
QuicTime::Delta TimeUntilAvailable() override;
// Implementation of Endpoint interface methods.
UnconstrainedPortInterface* GetRxPort() override;
void SetTxPort(ConstrainedPortInterface* port) override;
// Implementation of Actor interface methods.
void Act() override;
protected:
// Returns true if the packet should be passed through, and false if it should
// be dropped. The function is called once per packet, in the order that the
// packets arrive, so it is safe for the function to alter the internal state
// of the filter.
virtual bool FilterPacket(const Packet& packet) = 0;
private:
// The port onto which the filtered packets are egressed.
ConstrainedPortInterface* output_tx_port_;
// The original network endpoint wrapped by the class.
Endpoint* input_;
};
} // namespace simulator
} // namespace quic
#endif // QUICHE_QUIC_TEST_TOOLS_SIMULATOR_PACKET_FILTER_H_
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