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/*
* Copyright (C) 2021 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 <libnl++/Socket.h>
#include <mutex>
#include <thread>
namespace android::nlinterceptor {
class InterceptorRelay {
public:
/**
* Wrapper around the netlink socket and thread which relays messages.
*
* \param nlFamily - netlink family to use for the netlink socket.
* \param clientNlPid - pid of the client netlink socket.
* \param clientName - name of the client to be used for debugging.
*/
InterceptorRelay(uint32_t nlFamily, uint32_t clientNlPid,
const std::string& clientName);
/**
* Stops the relay thread if running and destroys itself.
*/
~InterceptorRelay();
/**
* Returns the PID of the internal Netlink socket.
*
* \return value of PID,
*/
uint32_t getPid();
/**
* Spawns relay thread.
*/
bool start();
/**
* Subscribes the internal socket to a single Netlink multicast group.
*
* \param nlGroup - Netlink group to subscribe to.
* \returns - true for success, false for failure.
*/
bool subscribeGroup(uint32_t nlGroup);
/**
* Unsubscribes the internal socket from a single Netlink multicast group.
*
* \param nlGroup - Netlink group to unsubscribe from.
* \returns - true for success, false for failure.
*/
bool unsubscribeGroup(uint32_t nlGroup);
private:
std::string mClientName; ///< Name of client (Wificond, for example).
std::optional<nl::Socket> mNlSocket;
const uint32_t mClientNlPid = 0; ///< pid of client NL socket.
/**
* If set to true, the relay thread should be running. Setting this to false
* stops the relay thread.
*/
std::atomic_bool mRunning = false;
/**
* Reads incoming Netlink messages destined for mNlSocket. If from the
* kernel, the message is relayed to the client specified in the
* constructor. Otherwise, the message is relayed to the kernel. This will
* run as long as mRunning is set to true.
*/
void relayMessages();
std::thread mRelayThread;
};
} // namespace android::nlinterceptor
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