network_state.cc

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// Copyright (C) 2017-2023 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
#include <config.h>
 
#include <exceptions/exceptions.h>
#include <dhcpsrv/network_state.h>
#include <dhcpsrv/timer_mgr.h>
#include <util/multi_threading_mgr.h>
#include <boost/enable_shared_from_this.hpp>
#include <functional>
#include <sstream>
#include <string>
#include <unordered_set>
 
using namespace isc::util;
 
namespace isc {
namespace dhcp {
 
class NetworkStateImpl : public boost::enable_shared_from_this<NetworkStateImpl> {
public:
 
    NetworkStateImpl(const NetworkState::ServerType& server_type)
        : server_type_(server_type), globally_disabled_(false),
          disabled_subnets_(), disabled_networks_(),
          timer_mgr_(TimerMgr::instance()), disabled_by_origin_(),
          disabled_by_db_connection_(0) {
    }
 
    ~NetworkStateImpl() {
        for (auto origin : disabled_by_origin_) {
            destroyTimer(origin);
        }
    }
 
    void setDisableService(const bool disable, unsigned int origin) {
        if (disable) {
            // Disable the service for any flag.
            globally_disabled_ = true;
            if (origin == NetworkState::DB_CONNECTION) {
                ++disabled_by_db_connection_;
            } else {
                disabled_by_origin_.insert(origin);
            }
        } else {
            if (origin == NetworkState::DB_CONNECTION) {
                // Never go below 0 (using unsigned type).
                // This should never happen anyway.
                if (disabled_by_db_connection_) {
                    --disabled_by_db_connection_;
                }
            } else {
                disabled_by_origin_.erase(origin);
            }
            // Enable the service only if all flags have been cleared.
            if (disabled_by_origin_.empty() && disabled_by_db_connection_ == 0) {
                globally_disabled_ = false;
            }
        }
    }
 
    void resetForDbConnection() {
        disabled_by_db_connection_ = 0;
        if (disabled_by_origin_.empty()) {
            globally_disabled_ = false;
        }
    }
 
    void delayedEnable(unsigned int origin) {
        setDisableService(false, origin);
        destroyTimer(origin);
    }
 
    void createTimer(const unsigned int seconds, unsigned int origin) {
        destroyTimer(origin);
        if (origin == NetworkState::DB_CONNECTION) {
            isc_throw(BadValue, "DB connection does not support delayed enable");
        }
        auto timer_name = getTimerName(origin);
        timer_mgr_->registerTimer(timer_name,
                                  std::bind(&NetworkStateImpl::delayedEnable,
                                            shared_from_this(), origin),
                                  seconds * 1000,
                                  asiolink::IntervalTimer::ONE_SHOT);
        timer_mgr_->setup(timer_name);
    }
 
    void destroyTimer(unsigned int origin) {
        if (origin == NetworkState::DB_CONNECTION) {
            return;
        }
        auto timer_name = getTimerName(origin);
        if (timer_mgr_->isTimerRegistered(timer_name)) {
            timer_mgr_->unregisterTimer(timer_name);
        }
    }
 
    std::string getTimerName(unsigned int origin) const {
        std::ostringstream timer_name;
        timer_name << "network-state-timer-" << origin;
        return (timer_name.str());
    }
 
    NetworkState::ServerType server_type_;
 
    bool globally_disabled_;
 
    NetworkState::Subnets disabled_subnets_;
 
    NetworkState::Networks disabled_networks_;
 
    TimerMgrPtr timer_mgr_;
 
    std::unordered_set<unsigned int> disabled_by_origin_;
 
    uint32_t disabled_by_db_connection_;
};
 
NetworkState::NetworkState(const NetworkState::ServerType& server_type)
    : impl_(new NetworkStateImpl(server_type)), mutex_(new std::mutex()) {
}
 
void
NetworkState::disableService(unsigned int origin) {
    MultiThreadingLock lock(*mutex_);
    impl_->setDisableService(true, origin);
}
 
void
NetworkState::enableService(unsigned int origin) {
    MultiThreadingLock lock(*mutex_);
    impl_->delayedEnable(origin);
}
 
void
NetworkState::resetForDbConnection() {
    MultiThreadingLock lock(*mutex_);
    impl_->resetForDbConnection();
}
 
void
NetworkState::delayedEnableService(const unsigned int seconds, unsigned int origin) {
    MultiThreadingLock lock(*mutex_);
    impl_->createTimer(seconds, origin);
}
 
bool
NetworkState::isServiceEnabled() const {
    MultiThreadingLock lock(*mutex_);
    return (!impl_->globally_disabled_);
}
 
bool
NetworkState::isDelayedEnableService() const {
    for (auto origin : impl_->disabled_by_origin_) {
        if (TimerMgr::instance()->isTimerRegistered(impl_->getTimerName(origin))) {
            return (true);
        }
    }
    return (false);
}
 
void
NetworkState::selectiveDisable(const NetworkState::Subnets&) {
    isc_throw(NotImplemented, "selectiveDisableService is not implemented");
}
 
void
NetworkState::selectiveDisable(const NetworkState::Networks&) {
    isc_throw(NotImplemented, "selectiveDisableService is not implemented");
}
 
void
NetworkState::selectiveEnable(const NetworkState::Subnets&) {
    isc_throw(NotImplemented, "selectiveEnableService is not implemented");
}
 
void
NetworkState::selectiveEnable(const NetworkState::Networks&) {
    isc_throw(NotImplemented, "selectiveEnableService is not implemented");
}
 
} // end of namespace isc::dhcp
} // end of namespace isc