common/vsoc/shm/socket_forward_layout.h

/*
 * Copyright (C) 2018 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#pragma once

#include "common/vsoc/shm/base.h"
#include "common/vsoc/shm/circqueue.h"
#include "common/vsoc/shm/lock.h"
#include "common/vsoc/shm/version.h"

// Memory layout for wifi packet exchange region.
namespace vsoc {
namespace layout {
namespace socket_forward {

constexpr std::size_t kMaxPacketSize = 8192;

struct QueuePair {
  // Traffic originating from host that proceeds towards guest.
  CircularPacketQueue<16, kMaxPacketSize> host_to_guest;
  // Traffic originating from guest that proceeds towards host.
  CircularPacketQueue<16, kMaxPacketSize> guest_to_host;

  enum QueueState : std::uint32_t {
    INACTIVE = 0,
    HOST_CONNECTED = 1,
    BOTH_CONNECTED = 2,
    HOST_CLOSED = 3,
    GUEST_CLOSED = 4,
    // If both are closed then the queue goes back to INACTIVE
    // BOTH_CLOSED = 0,
  };
  QueueState queue_state_;
  std::uint32_t port_;

  SpinLock queue_state_lock_;

  bool Recover() {
    bool recovered = false;
    bool rval = host_to_guest.Recover();
    recovered = recovered || rval;
    rval = guest_to_host.Recover();
    recovered = recovered || rval;
    rval = queue_state_lock_.Recover();
    recovered = recovered || rval;
    // TODO: Put queue_state_ and port_ recovery here, probably after grabbing
    // the queue_state_lock_.
    return recovered;
  }
};

struct SocketForwardLayout : public RegionLayout {
  bool Recover() {
    bool recovered = false;
    for (auto& i : queues_) {
      bool rval = i.Recover();
      recovered = recovered || rval;
    }
    //TODO: consider handling the sequence number here
    return recovered;
  }

  QueuePair queues_[version_info::socket_forward::kNumQueues];
  std::atomic_uint32_t seq_num;
  static const char* region_name;
};

ASSERT_SHM_COMPATIBLE(SocketForwardLayout, socket_forward);

}  // namespace socket_forward
}  // namespace layout
}  // namespace vsoc