Holds information about DHCP service enabling status. More...

#include <network_state.h>

Public Types
typedef std::set< std::string >	Networks
	Type of the container holding collection of shared network names. More...

enum	Origin { Origin::USER_COMMAND, Origin::HA_COMMAND, Origin::DB_CONNECTION }
	Origin of the network state transition. More...

enum	ServerType { DHCPv4, DHCPv6 }
	DHCP server type. More...

typedef std::set< SubnetID >	Subnets
	Type of the container holding collection of subnet identifiers. More...

Public Member Functions
	NetworkState (const ServerType &server_type)
	Constructor. More...

void	delayedEnableAll (const unsigned int seconds, const NetworkState::Origin &origin)
	Schedules enabling DHCP service in the future. More...

void	disableService (const NetworkState::Origin &origin)
	Disable the DHCP service state for respective transition origin. More...

void	enableAll (const NetworkState::Origin &origin)
	Enables DHCP service globally and for scopes which have been disabled as a result of control command. More...

void	enableService (const NetworkState::Origin &origin)
	Enable the DHCP service state for respective transition origin. More...

bool	isDelayedEnableAll () const
	Checks if delayed enabling of DHCP services is scheduled. More...

bool	isServiceEnabled () const
	Checks if the DHCP service is globally enabled. More...

void	reset (const NetworkState::Origin &type)
	Reset internal counters. More...

Selective disabling/enabling DHCP service per scopes
void	selectiveDisable (const NetworkState::Subnets &subnets)
	Disable DHCP service for selected subnets. More...

void	selectiveDisable (const NetworkState::Networks &networks)
	Disable DHCP service for selected networks. More...

void	selectiveEnable (const NetworkState::Subnets &subnets)
	Enable DHCP service for selected subnets. More...

void	selectiveEnable (const NetworkState::Networks &networks)
	Enable DHCP service for selected networks. More...

Detailed Description

Holds information about DHCP service enabling status.

When the DHCP server receives a command to disable DHCP service entirely or for specific networks, this has to be recorded to allow for re-enabling DHCP service for these networks as a result of receiving a command from the administrator or when the timeout for re-enabling the service occurs. Currently there are two types of command originating either from user or HA internal mechanism. The global state can also be altered by the DB recovery mechanism which disables the service on connection loss and re-enables it after the connection is restored. Because the server supports recovery for multiple connections, this is implemented using an internal counter. Combining all the origins of the alteration of the network state, the behavior is: a) the network state is disabled if any of the originators explicitly set the disabled flag. b) the network state is restored only if all originators explicitly clear the disabled flag. In the future, it will be possible to specify "disabled" parameter for a subnet (or network) in the configuration file to indicate that this subnet should be excluded from the service. When a command is subsequently sent to temporarily disable a service for some other subnets for a specified amount of time, only these subnets should be re-enabled when the time elapses. This class fulfills this requirement by recording the subnets disabled with a command and re-enabling them when required. The subnets specified as "disabled" in the configuration file should remain disabled until explicitly enabled with a control command.

This class also allows for disabling the DHCP service globally. In this case the server drops all received packets.

The "dhcp-disable" and "dhcp-enable" commands are used for globally disabling and enabling the DHCP service. The "dhcp-disable-scopes" and "dhcp-enable-scopes" commands are used to disable and enable DHCP service for subnets and networks. In case of the "dhcp-disable" and "dhcp-disable-scopes" commands, it is possible to specify "max-period" parameter which provides a timeout, after which the settings are reverted (service is re-enabled globally and/or for specific scopes).

Disabling DHCP service with a timeout is useful to guard against issues when the controlling client dies after disabling the DHCP service on the server, e.g. failover peers may instruct each other to disable the DHCP service while database synchronization takes place. If the peer subsequently dies, the surviving server must re-enable DHCP on its own.

Todo:: This class currently supports only the case of globally disabling the DHCP service. Disabling per network/subnet will be added later.

Definition at line 70 of file network_state.h.

Member Typedef Documentation

typedef std::set<std::string> isc::dhcp::NetworkState::Networks

Type of the container holding collection of shared network names.

Definition at line 98 of file network_state.h.

typedef std::set<SubnetID> isc::dhcp::NetworkState::Subnets

Type of the container holding collection of subnet identifiers.

Definition at line 95 of file network_state.h.

Member Enumeration Documentation

enum isc::dhcp::NetworkState::Origin

strong

Origin of the network state transition.

The enumeration indicates the originator of the state transition of the network state: either user command, HA internal command or DB connection recovery mechanism.

Enumerator
USER_COMMAND	The network state is being altered by a user command.
HA_COMMAND	The network state is being altered by a HA internal command.
DB_CONNECTION	The network state is being altered by the DB connection recovery mechanics.

Definition at line 84 of file network_state.h.

enum isc::dhcp::NetworkState::ServerType

DHCP server type.

Enumerator
DHCPv4
DHCPv6

Definition at line 74 of file network_state.h.

Constructor & Destructor Documentation

isc::dhcp::NetworkState::NetworkState ( const ServerType & server_type )

Constructor.

Definition at line 240 of file network_state.cc.

Member Function Documentation

void isc::dhcp::NetworkState::delayedEnableAll	(	const unsigned int	seconds,
		const NetworkState::Origin &	origin
	)

Schedules enabling DHCP service in the future.

Parameters

seconds	Number of seconds after which the service should be enabled unless `enableAll` is enabled before that time.
origin	The origin of the state transition.

Definition at line 285 of file network_state.cc.

void isc::dhcp::NetworkState::disableService ( const NetworkState::Origin & origin )

Disable the DHCP service state for respective transition origin.

Note: If any of the user commands, HA internal commands or connection recovery processes disable the dhcp service, the service will remain disabled until all flags are cleared.

Parameters

origin The origin of the state transition.

Definition at line 245 of file network_state.cc.

void isc::dhcp::NetworkState::enableAll ( const NetworkState::Origin & origin )

Enables DHCP service globally and for scopes which have been disabled as a result of control command.

Parameters

origin The origin of the state transition.

Definition at line 275 of file network_state.cc.

void isc::dhcp::NetworkState::enableService ( const NetworkState::Origin & origin )

Enable the DHCP service state for respective transition origin.

Note: If any of the user commands, HA internal commands or connection recovery processes disable the dhcp service, the service will remain disabled until all flags are cleared.

Parameters

origin The origin of the state transition.

Definition at line 255 of file network_state.cc.

bool isc::dhcp::NetworkState::isDelayedEnableAll ( ) const

Checks if delayed enabling of DHCP services is scheduled.

It indicates that the timer is present which counts the time until enableAll function will be called automatically.

Returns: true if delayed enabling of the DHCP service is scheduled, false otherwise.

Definition at line 306 of file network_state.cc.

References isc::dhcp::TimerMgr::instance().

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bool isc::dhcp::NetworkState::isServiceEnabled ( ) const

Checks if the DHCP service is globally enabled.

Returns: true if the service is globally enabled, false otherwise.

Definition at line 296 of file network_state.cc.

void isc::dhcp::NetworkState::reset ( const NetworkState::Origin & type )

Reset internal counters.

Reset internal counters for a specific 'origin' after the server has been reconfigured or all the connections have been restored.

Parameters

type	The origin for which the state flags need to be reset.

Definition at line 265 of file network_state.cc.

void isc::dhcp::NetworkState::selectiveDisable ( const NetworkState::Subnets & subnets )

Disable DHCP service for selected subnets.

Parameters

subnets Collection of subnet identifiers for which the service should be disabled.

Exceptions

isc::NotImplemented

Definition at line 312 of file network_state.cc.

References isc_throw.

void isc::dhcp::NetworkState::selectiveDisable ( const NetworkState::Networks & networks )

Disable DHCP service for selected networks.

Parameters

networks Collection of shared network names for which the service should be disabled.

Exceptions

isc::NotImplemented

Definition at line 317 of file network_state.cc.

References isc_throw.

void isc::dhcp::NetworkState::selectiveEnable ( const NetworkState::Subnets & subnets )

Enable DHCP service for selected subnets.

Parameters

subnets Collection of subnet identifiers for which the service should be disabled.

Exceptions

isc::NotImplemented

Definition at line 322 of file network_state.cc.

References isc_throw.

void isc::dhcp::NetworkState::selectiveEnable ( const NetworkState::Networks & networks )

Enable DHCP service for selected networks.

Parameters

networks Collection of shared network names for which the service should be enabled.

Exceptions

isc::NotImplemented

Definition at line 327 of file network_state.cc.

References isc_throw.

The documentation for this class was generated from the following files:

Public Types

Public Member Functions

Detailed Description

Member Typedef Documentation

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation