chromium/net/third_party/quiche/src/quiche/quic/test_tools/simulator/packet_filter.h

// 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 "quiche/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 { … };

}  // namespace simulator
}  // namespace quic
#endif  // QUICHE_QUIC_TEST_TOOLS_SIMULATOR_PACKET_FILTER_H_