ns3::TapBridge Class Reference
[Bridge]

A bridge to make it appear that a real host process is connected to an ns-3 net device. More...

#include <tap-bridge.h>

Inheritance diagram for ns3::TapBridge:

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List of all members.

Public Types

enum  Mode { ILLEGAL, CONFIGURE_LOCAL, USE_LOCAL, USE_BRIDGE }

Public Member Functions

Ptr< NetDeviceGetBridgedNetDevice (void)
 Get the bridged net device.
void SetBridgedNetDevice (Ptr< NetDevice > bridgedDevice)
 Set the ns-3 net device to bridge.
void Start (Time tStart)
 Set a start time for the device.
void Stop (Time tStop)
void SetMode (TapBridge::Mode mode)
TapBridge::Mode GetMode (void)
virtual void SetIfIndex (const uint32_t index)
virtual uint32_t GetIfIndex (void) const
virtual Ptr< ChannelGetChannel (void) const
virtual void SetAddress (Address address)
virtual Address GetAddress (void) const
virtual bool SetMtu (const uint16_t mtu)
virtual uint16_t GetMtu (void) const
virtual bool IsLinkUp (void) const
virtual void SetLinkChangeCallback (Callback< void > callback)
virtual bool IsBroadcast (void) const
virtual Address GetBroadcast (void) const
virtual bool IsMulticast (void) const
virtual Address GetMulticast (Ipv4Address multicastGroup) const
 Make and return a MAC multicast address using the provided multicast group.
virtual bool IsPointToPoint (void) const
 Return true if the net device is on a point-to-point link.
virtual bool IsBridge (void) const
 Return true if the net device is acting as a bridge.
virtual bool Send (Ptr< Packet > packet, const Address &dest, uint16_t protocolNumber)
virtual bool SendFrom (Ptr< Packet > packet, const Address &source, const Address &dest, uint16_t protocolNumber)
virtual Ptr< NodeGetNode (void) const
virtual void SetNode (Ptr< Node > node)
virtual bool NeedsArp (void) const
virtual void SetReceiveCallback (NetDevice::ReceiveCallback cb)
virtual void SetPromiscReceiveCallback (NetDevice::PromiscReceiveCallback cb)
virtual bool SupportsSendFrom () const
virtual Address GetMulticast (Ipv6Address addr) const
 Get the MAC multicast address corresponding to the IPv6 address provided.

Static Public Member Functions

static TypeId GetTypeId (void)
 This method returns the TypeId associated to ns3::TapBridge.

Protected Member Functions

virtual void DoDispose (void)


Detailed Description

A bridge to make it appear that a real host process is connected to an ns-3 net device.

The upshot is that the Tap Bridge appears to bridge a tap device on a Linux host in the "real world" to an ns-3 net device in the simulation and make is appear that a ns-3 net device is actually installed in the Linux host. In order to do this on the ns-3 side, we need a "ghost node" in the simulation to hold the bridged ns-3 net device and the TapBridge. This node should not actually do anything else in the simulation since its job is simply to make the net device appear in Linux. This is not just arbitrary policy, it is because:

Of course, if you understand all of the issues you can take control of your own destiny and do whatever you want -- we do not actively prevent you from using the ghost node for anything you decide. You will be able to perform typical ns-3 operations on the ghost node if you so desire. The internet stack, for example, must be there and functional on that node in order to participate in IP address assignment and global routing. However, as mentioned above, interfaces talking any Tap Bridge or associated bridged net devices will not work completely. If you understand exactly what you are doing, you can set up other interfaces and devices on the ghost node and use them; or take advantage of the operational send side of the bridged devices to create traffic generators. We generally recommend that you treat this node as a ghost of the Linux host and leave it to itself, though.


Member Enumeration Documentation

Enumeration of the operating modes supported in the class.

Enumerator:
ILLEGAL  mode not set
CONFIGURE_LOCAL  ns-3 creates and configures tap device
USE_LOCAL  ns-3 uses a pre-created tap, without configuring it
USE_BRIDGE  ns-3 uses a pre-created tap, and bridges to a bridging net device


Member Function Documentation

virtual void ns3::TapBridge::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.

virtual Address ns3::TapBridge::GetAddress ( void   )  const [virtual]

Returns:
the current Address of this interface.

Implements ns3::NetDevice.

Ptr<NetDevice> ns3::TapBridge::GetBridgedNetDevice ( void   ) 

Get the bridged net device.

The bridged net device is the ns-3 device to which this bridge is connected,

Returns:
the bridged net device.

virtual Address ns3::TapBridge::GetBroadcast ( void   )  const [virtual]

Returns:
the broadcast address supported by this netdevice.
Calling this method is invalid if IsBroadcast returns not true.

Implements ns3::NetDevice.

virtual Ptr<Channel> ns3::TapBridge::GetChannel ( void   )  const [virtual]

Returns:
the channel this NetDevice is connected to. The value returned can be zero if the NetDevice is not yet connected to any channel or if the underlying NetDevice has no concept of a channel. i.e., callers _must_ check for zero and be ready to handle it.

Implements ns3::NetDevice.

virtual uint32_t ns3::TapBridge::GetIfIndex ( void   )  const [virtual]

Returns:
index ifIndex of the device

Implements ns3::NetDevice.

TapBridge::Mode ns3::TapBridge::GetMode ( void   ) 

Get the operating mode of this device.

Returns:
The operating mode of this device.

virtual uint16_t ns3::TapBridge::GetMtu ( void   )  const [virtual]

Returns:
the link-level MTU in bytes for this interface.
This value is typically used by the IP layer to perform IP fragmentation when needed.

Implements ns3::NetDevice.

virtual Address ns3::TapBridge::GetMulticast ( Ipv6Address  addr  )  const [virtual]

Get the MAC multicast address corresponding to the IPv6 address provided.

Parameters:
addr IPv6 address
Returns:
the MAC multicast address
Warning:
Calling this method is invalid if IsMulticast returns not true.

Implements ns3::NetDevice.

virtual Address ns3::TapBridge::GetMulticast ( Ipv4Address  multicastGroup  )  const [virtual]

Make and return a MAC multicast address using the provided multicast group.

RFC 1112 says that an Ipv4 host group address is mapped to an Ethernet multicast address by placing the low-order 23-bits of the IP address into the low-order 23 bits of the Ethernet multicast address 01-00-5E-00-00-00 (hex). Similar RFCs exist for Ipv6 and Eui64 mappings. This method performs the multicast address creation function appropriate to the underlying MAC address of the device. This MAC address is encapsulated in an abstract Address to avoid dependencies on the exact MAC address format.

A default imlementation of GetMulticast is provided, but this method simply NS_ASSERTS. In the case of net devices that do not support multicast, clients are expected to test NetDevice::IsMulticast and avoid attempting to map multicast packets. Subclasses of NetDevice that do support multicasting are expected to override this method and provide an implementation appropriate to the particular device.

Parameters:
multicastGroup The IP address for the multicast group destination of the packet.
Returns:
The MAC multicast Address used to send packets to the provided multicast group.
Warning:
Calling this method is invalid if IsMulticast returns not true.
See also:
Ipv4Address

Address

NetDevice::IsMulticast

Implements ns3::NetDevice.

virtual Ptr<Node> ns3::TapBridge::GetNode ( void   )  const [virtual]

Returns:
the node base class which contains this network interface.
When a subclass needs to get access to the underlying node base class to print the nodeid for example, it can invoke this method.

Implements ns3::NetDevice.

static TypeId ns3::TapBridge::GetTypeId ( void   )  [static]

This method returns the TypeId associated to ns3::TapBridge.

This object is accessible through the following paths with Config::Set and Config::Connect:

  • /NodeList/[i]/DeviceList/[i]/$ns3::TapBridge
Attributes defined for this type:
  • DeviceName: The name of the tap device to create.
    • Set with class: StringValue
    • Underlying type: std::string
    • Initial value:
    • Flags: construct write read
  • Gateway: The IP address of the default gateway to assign to the host machine, when in ConfigureLocal mode.
  • IpAddress: The IP address to assign to the tap device, when in ConfigureLocal mode. This address will override the discovered IP address of the simulated device.
  • MacAddress: The MAC address to assign to the tap device, when in ConfigureLocal mode. This address will override the discovered MAC address of the simulated device.
  • Netmask: The network mask to assign to the tap device, when in ConfigureLocal mode. This address will override the discovered MAC address of the simulated device.
    • Set with class: Ipv4MaskValue
    • Underlying type: Ipv4Mask
    • Initial value: 255.255.255.255
    • Flags: construct write read
  • Start: The simulation time at which to spin up the tap device read thread.
    • Set with class: TimeValue
    • Underlying type: Time
    • Initial value: 0ns
    • Flags: construct write read
  • Stop: The simulation time at which to tear down the tap device read thread.
    • Set with class: TimeValue
    • Underlying type: Time
    • Initial value: 0ns
    • Flags: construct write read
  • Mode: The operating and configuration mode to use.
    • Set with class: ns3::EnumValue
    • Underlying type: ConfigureLocal|UseLocal|UseBridge
    • Initial value: UseLocal
    • Flags: construct write
Attributes defined in parent class ns3::NetDevice:
  • Mtu: The MAC-level Maximum Transmission Unit
No TraceSources defined for this type.

Reimplemented from ns3::NetDevice.

virtual bool ns3::TapBridge::IsBridge ( void   )  const [virtual]

Return true if the net device is acting as a bridge.

Returns:
value of m_isBridge flag

Implements ns3::NetDevice.

virtual bool ns3::TapBridge::IsBroadcast ( void   )  const [virtual]

Returns:
true if this interface supports a broadcast address, false otherwise.

Implements ns3::NetDevice.

virtual bool ns3::TapBridge::IsLinkUp ( void   )  const [virtual]

Returns:
true if link is up; false otherwise

Implements ns3::NetDevice.

virtual bool ns3::TapBridge::IsMulticast ( void   )  const [virtual]

Returns:
value of m_isMulticast flag

Implements ns3::NetDevice.

virtual bool ns3::TapBridge::IsPointToPoint ( void   )  const [virtual]

Return true if the net device is on a point-to-point link.

Returns:
value of m_isPointToPoint flag

Implements ns3::NetDevice.

virtual bool ns3::TapBridge::NeedsArp ( void   )  const [virtual]

Returns:
true if ARP is needed, false otherwise.
Called by higher-layers to check if this NetDevice requires ARP to be used.

Implements ns3::NetDevice.

virtual bool ns3::TapBridge::Send ( Ptr< Packet packet,
const Address dest,
uint16_t  protocolNumber 
) [virtual]

Parameters:
packet packet sent from above down to Network Device
dest mac address of the destination (already resolved)
protocolNumber identifies the type of payload contained in this packet. Used to call the right L3Protocol when the packet is received.
Called from higher layer to send packet into Network Device to the specified destination Address

Returns:
whether the Send operation succeeded

Implements ns3::NetDevice.

virtual bool ns3::TapBridge::SendFrom ( Ptr< Packet packet,
const Address source,
const Address dest,
uint16_t  protocolNumber 
) [virtual]

Parameters:
packet packet sent from above down to Network Device
source source mac address (so called "MAC spoofing")
dest mac address of the destination (already resolved)
protocolNumber identifies the type of payload contained in this packet. Used to call the right L3Protocol when the packet is received.
Called from higher layer to send packet into Network Device with the specified source and destination Addresses.

Returns:
whether the Send operation succeeded

Implements ns3::NetDevice.

virtual void ns3::TapBridge::SetAddress ( Address  address  )  [virtual]

Set the address of this interface

Implements ns3::NetDevice.

void ns3::TapBridge::SetBridgedNetDevice ( Ptr< NetDevice bridgedDevice  ) 

Set the ns-3 net device to bridge.

This method tells the bridge which ns-3 net device it should use to connect the simulation side of the bridge.

Attention:
The ns-3 net device that is being set as the device must have an an IP address assigned to it before the simulation is run. This address will be used to set the hardware address of the host Linux device.

virtual void ns3::TapBridge::SetIfIndex ( const uint32_t  index  )  [virtual]

Parameters:
index ifIndex of the device

Implements ns3::NetDevice.

virtual void ns3::TapBridge::SetLinkChangeCallback ( Callback< void >  callback  )  [virtual]

Parameters:
callback the callback to invoke
Register a callback invoked whenever the link status changes to UP. This callback is typically used by the IP/ARP layer to flush the ARP cache whenever the link goes up.

Implements ns3::NetDevice.

void ns3::TapBridge::SetMode ( TapBridge::Mode  mode  ) 

Set the operating mode of this device.

Parameters:
mode The operating mode of this device.

virtual bool ns3::TapBridge::SetMtu ( const uint16_t  mtu  )  [virtual]

Parameters:
mtu MTU value, in bytes, to set for the device
Returns:
whether the MTU value was within legal bounds
Override for default MTU defined on a per-type basis.

Implements ns3::NetDevice.

virtual void ns3::TapBridge::SetNode ( Ptr< Node node  )  [virtual]

Parameters:
node the node associated to this netdevice.
This method is called from ns3::Node::AddDevice.

Implements ns3::NetDevice.

virtual void ns3::TapBridge::SetPromiscReceiveCallback ( NetDevice::PromiscReceiveCallback  cb  )  [virtual]

Parameters:
cb callback to invoke whenever a packet has been received in promiscuous mode and must be forwarded to the higher layers.
Enables netdevice promiscuous mode and sets the callback that will handle promiscuous mode packets. Note, promiscuous mode packets means _all_ packets, including those packets that can be sensed by the netdevice but which are intended to be received by other hosts.

Implements ns3::NetDevice.

virtual void ns3::TapBridge::SetReceiveCallback ( NetDevice::ReceiveCallback  cb  )  [virtual]

Parameters:
cb callback to invoke whenever a packet has been received and must be forwarded to the higher layers.

Implements ns3::NetDevice.

void ns3::TapBridge::Start ( Time  tStart  ) 

Set a start time for the device.

The tap bridge consumes a non-trivial amount of time to start. It starts up in the context of a scheduled event to ensure that all configuration has been completed before extracting the configuration (IP addresses, etc.) In order to allow a more reasonable start-up sequence than a thundering herd of devices, the time at which each device starts is also configurable bot via the Attribute system and via this call.

Parameters:
tStart the start time

void ns3::TapBridge::Stop ( Time  tStop  ) 

Set a stop time for the device.

Parameters:
tStop the stop time
See also:
TapBridge::Start

virtual bool ns3::TapBridge::SupportsSendFrom (  )  const [virtual]

Returns:
true if this interface supports a bridging mode, false otherwise.

Implements ns3::NetDevice.


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

Generated on Fri Apr 9 15:01:09 2010 for NS-3 by  doxygen 1.5.8