Static routing protocol for IP version 4 stacks. More...

#include <ipv4-static-routing.h>

Inheritance diagram for ns3::Ipv4StaticRouting:

Collaboration diagram for ns3::Ipv4StaticRouting:

Public Member Functions
	Ipv4StaticRouting ()
	Construct an empty Ipv4StaticRouting routing protocol,.
virtual bool	RequestRoute (uint32_t ifIndex, Ipv4Header const &ipHeader, Ptr< Packet > packet, RouteReplyCallback routeReply)
	Request that a check for a route bw performed and if a route is found that the packet be sent on its way using the pre-packaged send callback.
virtual bool	RequestIfIndex (Ipv4Address destination, uint32_t &ifIndex)
	Check to see if we can determine the interface index that will be used if a packet is sent to this destination.
void	AddHostRouteTo (Ipv4Address dest, Ipv4Address nextHop, uint32_t interface)
	Add a host route to the static routing table.
void	AddHostRouteTo (Ipv4Address dest, uint32_t interface)
	Add a host route to the static routing table.
void	AddNetworkRouteTo (Ipv4Address network, Ipv4Mask networkMask, Ipv4Address nextHop, uint32_t interface)
	Add a network route to the static routing table.
void	AddNetworkRouteTo (Ipv4Address network, Ipv4Mask networkMask, uint32_t interface)
	Add a network route to the static routing table.
void	SetDefaultRoute (Ipv4Address nextHop, uint32_t interface)
	Add a default route to the static routing table.
uint32_t	GetNRoutes (void)
	Get the number of individual unicast routes that have been added to the routing table.
Ipv4Route *	GetDefaultRoute (void)
	Get the default route from the static routing table.
Ipv4Route *	GetRoute (uint32_t i)
	Get a route from the static unicast routing table.
void	RemoveRoute (uint32_t i)
	Remove a route from the static unicast routing table.
void	AddMulticastRoute (Ipv4Address origin, Ipv4Address group, uint32_t inputInterface, std::vector< uint32_t > outputInterfaces)
	Add a multicast route to the static routing table.
void	SetDefaultMulticastRoute (uint32_t outputInterface)
	Add a default multicast route to the static routing table.
uint32_t	GetNMulticastRoutes (void) const
	Get the number of individual multicast routes that have been added to the routing table.
Ipv4MulticastRoute *	GetMulticastRoute (uint32_t i) const
	Get a route from the static multicast routing table.
Ipv4MulticastRoute *	GetDefaultMulticastRoute (void) const
	Get the default multicast route from the static routing table.
bool	RemoveMulticastRoute (Ipv4Address origin, Ipv4Address group, uint32_t inputInterface)
	Remove a route from the static multicast routing table.
void	RemoveMulticastRoute (uint32_t index)
	Remove a route from the static multicast routing table.
Protected Member Functions
void	DoDispose (void)

Detailed Description

Static routing protocol for IP version 4 stacks.

In ns-3 we have the concept of a pluggable routing protocol. Routing protocols are added to a list maintained by the Ipv4L3Protocol. Every stack gets one routing protocol for free -- the Ipv4StaticRouting routing protocol is added in the constructor of the Ipv4L3Protocol (this is the piece of code that implements the functionality of the IP layer).

The Ipv4StaticRouting class inherits from the abstract base class Ipv4RoutingProtocol that defines the interface methods that a routing protocol must support.

When a packet arrives in the Ipv4L3Protocol for transmission, it comes either from a local source via Ipv4L3Protocol::Send or from a remote source via Ipv4L3Protocol::Forwarding. In both cases, a function is called (Ipv4L3Protocol::Lookup) to look up the routing information for the packet.

The lookup function iterates through the list of routing protocols asking each to see if it can find a route and send the packet. A callback is provided during each of these calls that should be considered a pre- packaged send call. This is done to allow asynchronous calls into routing subsystems in order to support on-demand routing, for example. The method for requesting this operation is Ipv4StaticRouting::RequestRoute for the static routing protocol.

Each routing protocol is also free to implement its own methods for managing routes which you will find below. This class manages a set of "static" or manually configured routes for host, network and multicast routes.

See also:: Ipv4RoutingProtocol; Ipv4L3Protocol::AddRoutingProtocol; Ipv4L3Protocol::Ipv4L3Protocol

Member Function Documentation

void ns3::Ipv4StaticRouting::AddHostRouteTo	(	Ipv4Address	dest,
		Ipv4Address	nextHop,
		uint32_t	interface
	)

Add a host route to the static routing table.

Parameters:

	dest	The Ipv4Address destination for this route.
	nextHop	The Ipv4Address of the next hop in the route.
	interface	The network interface index used to send packets to the destination.

See also:: Ipv4Address

void ns3::Ipv4StaticRouting::AddHostRouteTo	(	Ipv4Address	dest,
		uint32_t	interface
	)

Add a host route to the static routing table.

Parameters:

	dest	The Ipv4Address destination for this route.
	interface	The network interface index used to send packets to the destination.

See also:: Ipv4Address

void ns3::Ipv4StaticRouting::AddMulticastRoute	(	Ipv4Address	origin,
		Ipv4Address	group,
		uint32_t	inputInterface,
		std::vector< uint32_t >	outputInterfaces
	)

Add a multicast route to the static routing table.

A multicast route must specify an origin IP address, a multicast group and an input network interface index as conditions and provide a vector of output network interface indices over which packets matching the conditions are sent.

Typically there are two main types of multicast routes: routes of the first kind are used during forwarding. All of the conditions must be exlicitly provided. The second kind of routes are used to get packets off of a local node. The difference is in the input interface. Routes for forwarding will always have an explicit input interface specified. Routes off of a node will always set the input interface to a wildcard specified by the index Ipv4RoutingProtocol::IF_INDEX_ANY.

For routes off of a local node wildcards may be used in the origin and multicast group addresses. The wildcard used for Ipv4Adresses is that address returned by Ipv4Address::GetAny () -- typically "0.0.0.0". Usage of a wildcard allows one to specify default behavior to varying degrees.

For example, making the origin address a wildcard, but leaving the multicast group specific allows one (in the case of a node with multiple interfaces) to create different routes using different output interfaces for each multicast group.

If the origin and multicast addresses are made wildcards, you have created essentially a default multicast address that can forward to multiple interfaces. Compare this to the actual default multicast address that is limited to specifying a single output interface for compatibility with existing functionality in other systems.

Parameters:

	origin	The Ipv4Address of the origin of packets for this route. May be Ipv4Address:GetAny for open groups.
	group	The Ipv4Address of the multicast group or this route.
	inputInterface	The input network interface index over which to expect packets destined for this route. May be Ipv4RoutingProtocol::IF_INDEX_ANY for packets of local origin.
	outputInterfaces	A vector of network interface indices used to specify how to send packets to the destination(s).

See also:: Ipv4Address

void ns3::Ipv4StaticRouting::AddNetworkRouteTo	(	Ipv4Address	network,
		Ipv4Mask	networkMask,
		Ipv4Address	nextHop,
		uint32_t	interface
	)

Add a network route to the static routing table.

Parameters:

	network	The Ipv4Address network for this route.
	networkMask	The Ipv4Mask to extract the network.
	nextHop	The next hop in the route to the destination network.
	interface	The network interface index used to send packets to the destination.

See also:: Ipv4Address

void ns3::Ipv4StaticRouting::AddNetworkRouteTo	(	Ipv4Address	network,
		Ipv4Mask	networkMask,
		uint32_t	interface
	)

Add a network route to the static routing table.

Parameters:

	network	The Ipv4Address network for this route.
	networkMask	The Ipv4Mask to extract the network.
	interface	The network interface index used to send packets to the destination.

See also:: Ipv4Address

void ns3::Ipv4StaticRouting::DoDispose ( void ) [protected, virtual]

This method is called by Object::Dispose or by the object's destructor, whichever comes first.

Subclasses are expected to implement their real destruction code in an overriden version of this method and chain up to their parent's implementation once they are done. i.e., for simplicity, the destructor of every subclass should be empty and its content should be moved to the associated DoDispose method.

Reimplemented from ns3::Object.

Ipv4MulticastRoute* ns3::Ipv4StaticRouting::GetDefaultMulticastRoute ( void ) const

Get the default multicast route from the static routing table.

Returns:: If the default route is set, a pointer to that Ipv4MulticastRoute is returned, otherwise a zero pointer is returned.

See also:: Ipv4Route

Ipv4Route* ns3::Ipv4StaticRouting::GetDefaultRoute ( void )

Get the default route from the static routing table.

Returns:: If the default route is set, a pointer to that Ipv4Route is returned, otherwise a zero pointer is returned.

See also:: Ipv4Route

Ipv4MulticastRoute* ns3::Ipv4StaticRouting::GetMulticastRoute ( uint32_t i ) const

Get a route from the static multicast routing table.

Externally, the multicast static routing table appears simply as a table with n entries. The one sublety of note is that if a default route has been set it will appear as the zeroth entry in the table. This means that if you add only a default route, the table will have one entry that can be accessed either by explicity calling GetDefaultMulticastRoute () or by calling GetMulticastRoute (0).

Similarly, if the default route has been set, calling RemoveMulticastRoute (0) will remove the default route.

Parameters:

i

The index (into the routing table) of the multicast route to retrieve. If the default route has been set, it will occupy index zero.

Returns:: If route i is set, a pointer to that Ipv4MulticastRoute is returned, otherwise a zero pointer is returned.

See also:: Ipv4MulticastRoute; Ipv4StaticRouting::RemoveRoute

uint32_t ns3::Ipv4StaticRouting::GetNMulticastRoutes ( void ) const

Get the number of individual multicast routes that have been added to the routing table.

Warning:: The default multicast route counts as one of the routes.

uint32_t ns3::Ipv4StaticRouting::GetNRoutes ( void )

Get the number of individual unicast routes that have been added to the routing table.

Warning:: The default route counts as one of the routes.

Ipv4Route* ns3::Ipv4StaticRouting::GetRoute ( uint32_t i )

Get a route from the static unicast routing table.

Externally, the unicast static routing table appears simply as a table with n entries. The one sublety of note is that if a default route has been set it will appear as the zeroth entry in the table. This means that if you add only a default route, the table will have one entry that can be accessed either by explicity calling GetDefaultRoute () or by calling GetRoute (0).

Similarly, if the default route has been set, calling RemoveRoute (0) will remove the default route.

Parameters:

i

The index (into the routing table) of the route to retrieve. If the default route has been set, it will occupy index zero.

Returns:: If route is set, a pointer to that Ipv4Route is returned, otherwise a zero pointer is returned.

See also:: Ipv4Route; Ipv4StaticRouting::RemoveRoute

void ns3::Ipv4StaticRouting::RemoveMulticastRoute ( uint32_t index )

Remove a route from the static multicast routing table.

Externally, the multicast static routing table appears simply as a table with n entries. The one sublety of note is that if a default multicast route has been set it will appear as the zeroth entry in the table. This means that if the default route has been set, calling RemoveMulticastRoute (0) will remove the default route.

Parameters:

index

The index (into the multicast routing table) of the route to remove. If the default route has been set, it will occupy index zero.

See also:: Ipv4Route; Ipv4StaticRouting::GetRoute; Ipv4StaticRouting::AddRoute

bool ns3::Ipv4StaticRouting::RemoveMulticastRoute	(	Ipv4Address	origin,
		Ipv4Address	group,
		uint32_t	inputInterface
	)

Remove a route from the static multicast routing table.

Externally, the multicast static routing table appears simply as a table with n entries. The one sublety of note is that if a default multicast route has been set it will appear as the zeroth entry in the table. This means that the default route may be removed by calling this method with appropriate wildcard parameters.

This method causes the multicast routing table to be searched for the first route that matches the parameters and removes it.

Wildcards may be provided to this function, but the wildcards are used to exacly match wildcards in the routes (see AddMulticastRoute). That is, calling RemoveMulticastRoute with the origin set to "0.0.0.0" will not remove routes with any address in the origin, but will only remove routes with "0.0.0.0" set as the the origin.

Parameters:

	origin	The IP address specified as the origin of packets for the route.
	group	The IP address specified as the multicast group addres of the route.
	inputInterface	The network interface index specified as the expected input interface for the route.

Returns:: true if a route was found and removed, false otherwise.

See also:: Ipv4MulticastRoute; Ipv4StaticRouting::AddMulticastRoute

void ns3::Ipv4StaticRouting::RemoveRoute ( uint32_t i )

Remove a route from the static unicast routing table.

Externally, the unicast static routing table appears simply as a table with n entries. The one sublety of note is that if a default route has been set it will appear as the zeroth entry in the table. This means that if the default route has been set, calling RemoveRoute (0) will remove the default route.

Parameters:

i

The index (into the routing table) of the route to remove. If the default route has been set, it will occupy index zero.

See also:: Ipv4Route; Ipv4StaticRouting::GetRoute; Ipv4StaticRouting::AddRoute

virtual bool ns3::Ipv4StaticRouting::RequestIfIndex	(	Ipv4Address	destination,
		uint32_t &	ifIndex
	)			`[virtual]`

Check to see if we can determine the interface index that will be used if a packet is sent to this destination.

This method addresses a problem in the IP stack where a destination address must be present and checksummed into the IP header before the actual interface over which the packet is sent can be determined. The answer is to implement a known and intentional cross-layer violation. This is the endpoint of a call chain that started up quite high in the stack (sockets) and has found its way down to the Ipv4L3Protocol which is consulting the routing protocols for what they would do if presented with a packet of the given destination.

Note that the a single interface index is returned. This means that if the destination address is a multicast, and an explicit route is present that includeds multiple output interfaces, that route cannot be used.

If there are multiple paths out of the node, the resolution is performed by Ipv4L3Protocol::GetIfIndexforDestination which has access to more contextual information that is useful for making a determination.

Parameters:

	destination	The Ipv4Address if the destination of a hypothetical packet. This may be a multicast group address.
	ifIndex	A reference to the interface index over which a packet sent to this destination would be sent.

Returns:: Returns true if a route is found to the destination that involves a single output interface index, otherwise returns false indicating that the next routing protocol should be consulted. In practice, the static routing protocol is the last chance protocol.

See also:: Ipv4StaticRouting; Ipv4RoutingProtocol; Ipv4L3Protocol

Implements ns3::Ipv4RoutingProtocol.

virtual bool ns3::Ipv4StaticRouting::RequestRoute	(	uint32_t	ifIndex,
		Ipv4Header const &	ipHeader,
		Ptr< Packet >	packet,
		RouteReplyCallback	routeReply
	)			`[virtual]`

Request that a check for a route bw performed and if a route is found that the packet be sent on its way using the pre-packaged send callback.

The source and destination IP addresses for the packet in question are found in the provided Ipv4Header. There are two major processing forks depending on the type of destination address.

If the destination address is unicast then the routing table is consulted for a route to the destination and if it is found, the routeReply callback is executed to send the packet (with the found route).

If the destination address is a multicast, then the exact processing steps depend on whether or not the packet has been sourced locally. This is determined by the parameter ifIndex. This is the interface index over which this packet was received. If the packet has not been received over a network interface, this index will be set to Ipv4RoutingProtocol::IF_INDEX_ANY (a very large number). In that case, we want to avoid the requirement that an explicit route out of each node must be set, so we don't do anything here.

If the packet is a multicast destination and has been received over a network interface, a call to this method implies that the packet is being forwarded. In that case, there must be an explicit route out of the node. A multicast route references the source address, the destination address (the multicast group) and the input interface in order to find a route. We consult the multicast routing table and, if a route is found, send the packet out of as many interfaces as required using the provided callback (think of it as a pre-packaged send call).

Parameters:

	ifIndex	The network interface index over which the packed was received. If the packet is from a local source, ifIndex will be set to Ipv4RoutingProtocol::IF_INDEX_ANY.
	ipHeader	the Ipv4Header containing the source and destination IP addresses for the packet.
	packet	The packet to be sent if a route is found.
	routeReply	A callback that packaged up the call to actually send the packet.

Returns:: Returns true if a route is found and the packet has been sent, otherwise returns false indicating that the next routing protocol should be consulted. In practice, the static routing protocol is the last chance protocol.

See also:: Ipv4StaticRouting; Ipv4RoutingProtocol

Implements ns3::Ipv4RoutingProtocol.

void ns3::Ipv4StaticRouting::SetDefaultMulticastRoute ( uint32_t outputInterface )

Add a default multicast route to the static routing table.

This is the multicast equivalent of the unicast version SetDefaultRoute. We tell the routing system what to do in the case where a specific route to a destination multicast group is not found. The system forwards packets out the specified interface in the hope that "something out there" knows better how to route the packet. This method is only used in initially sending packets off of a host. The default multicast route is not consulted during forwarding -- exact routes must be specified using AddMulticastRoute for that case.

Since we're basically sending packets to some entity we think may know better what to do, we don't pay attention to "subtleties" like origin address, nor do we worry about forwarding out multiple interfaces. If the default multicast route is set, it is returned as the selected route from LookupStatic irrespective of origin or multicast group if another specific route is not found.

Parameters:

outputInterface

The network interface index used to specify where to send packets in the case of unknown routes.

See also:: Ipv4Address

void ns3::Ipv4StaticRouting::SetDefaultRoute	(	Ipv4Address	nextHop,
		uint32_t	interface
	)

Add a default route to the static routing table.

This method tells the routing system what to do in the case where a specific route to a destination is not found. The system forwards packets to the specified node in the hope that it knows better how to route the packet.

If the default route is set, it is returned as the selected route from LookupStatic irrespective of destination address if no specific route is found.

Parameters:

	nextHop	The Ipv4Address to send packets to in the hope that they will be forwarded correctly.
	interface	The network interface index used to send packets.

See also:: Ipv4Address; Ipv4StaticRouting::Lookup

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

src/internet-stack/ipv4-static-routing.h

ns3::Ipv4StaticRouting Class Reference

Public Member Functions

Protected Member Functions

Detailed Description

Member Function Documentation