Border Routing Manager

This module includes definitions related to Border Routing Manager.

Summary

All the functions in this module require OPENTHREAD_CONFIG_BORDER_ROUTING_ENABLE to be enabled.

Border Routing Manager handles bi-directional routing between Thread network and adjacent infrastructure link (AIL).

It emits ICMRv6 ND Router Advertisement (RA) messages on AIL to advertise on-link and route prefixes. It also processes received RA messages from infrastructure and mirrors the discovered prefixes on the Thread Network Data to ensure devices on Thread mesh can reach AIL through the Border Router.

Routing Manager manages the Off-Mesh Routable (OMR) prefix on the Thread Network data which configures Thread devices with a suitable Off-Mesh Routable IPv6 address. It announces the reachability of this prefix on AIL by including it in the emitted RA messages as an IPv6 Route Information Option (RIO).

Routing Manager also monitors and adds on-link prefix on the infrastructure network. If a router on AIL is already providing RA messages containing an IPv6 Prefix Information Option (PIO) that enables IPv6 devices on the link to self-configure their own routable unicast IPv6 address, this address can be used by Thread devices to reach AIL. If Border Router finds no such RA message on AIL, it generates a ULA on-link prefix which it then advertises on AIL in the emitted RA messages.

Typedefs

otBorderRoutingPrefixTableEntry typedef
This structure represents an entry from the discovered prefix table.
otBorderRoutingPrefixTableIterator typedef
This structure represents an iterator to iterate through the Border Router's discovered prefix table.

Functions

otBorderRoutingGetFavoredOmrPrefix(otInstance *aInstance, otIp6Prefix *aPrefix, otRoutePreference *aPreference)
Gets the currently favored Off-Mesh-Routable (OMR) Prefix.
otBorderRoutingGetNat64Prefix(otInstance *aInstance, otIp6Prefix *aPrefix)
Gets the local NAT64 Prefix of the Border Router.
otBorderRoutingGetNextPrefixTableEntry(otInstance *aInstance, otBorderRoutingPrefixTableIterator *aIterator, otBorderRoutingPrefixTableEntry *aEntry)
This function iterates over the entries in the Border Router's discovered prefix table.
otBorderRoutingGetOmrPrefix(otInstance *aInstance, otIp6Prefix *aPrefix)
Gets the local Off-Mesh-Routable (OMR) Prefix, for example fdfc:1ff5:1512:5622::/64.
otBorderRoutingGetOnLinkPrefix(otInstance *aInstance, otIp6Prefix *aPrefix)
Gets the On-Link Prefix for the adjacent infrastructure link, for example fd41:2650:a6f5:0::/64.
otBorderRoutingGetRouteInfoOptionPreference(otInstance *aInstance)
This function gets the preference used when advertising Route Info Options (e.g., for discovered OMR prefixes) in Router Advertisement messages sent over the infrastructure link.
otBorderRoutingInit(otInstance *aInstance, uint32_t aInfraIfIndex, bool aInfraIfIsRunning)
This method initializes the Border Routing Manager on given infrastructure interface.
otBorderRoutingPrefixTableInitIterator(otInstance *aInstance, otBorderRoutingPrefixTableIterator *aIterator)
void
This function initializes an otBorderRoutingPrefixTableIterator.
otBorderRoutingSetEnabled(otInstance *aInstance, bool aEnabled)
Enables or disables the Border Routing Manager.
otBorderRoutingSetRouteInfoOptionPreference(otInstance *aInstance, otRoutePreference aPreference)
void
This function sets the preference to use when advertising Route Info Options in Router Advertisement messages sent over the infrastructure link, for example for discovered OMR prefixes.

Structs

otBorderRoutingPrefixTableEntry

This structure represents an entry from the discovered prefix table.

otBorderRoutingPrefixTableIterator

This structure represents an iterator to iterate through the Border Router's discovered prefix table.

Typedefs

otBorderRoutingPrefixTableEntry

struct otBorderRoutingPrefixTableEntry otBorderRoutingPrefixTableEntry

This structure represents an entry from the discovered prefix table.

The entries in the discovered table track the Prefix/Route Info Options in the received Router Advertisement messages from other routers on infrastructure link.

otBorderRoutingPrefixTableIterator

struct otBorderRoutingPrefixTableIterator otBorderRoutingPrefixTableIterator

This structure represents an iterator to iterate through the Border Router's discovered prefix table.

The fields in this type are opaque (intended for use by OpenThread core only) and therefore should not be accessed or used by caller.

Before using an iterator, it MUST be initialized using otBorderRoutingPrefixTableInitIterator().

Functions

otBorderRoutingGetFavoredOmrPrefix

otError otBorderRoutingGetFavoredOmrPrefix(
  otInstance *aInstance,
  otIp6Prefix *aPrefix,
  otRoutePreference *aPreference
)

Gets the currently favored Off-Mesh-Routable (OMR) Prefix.

The favored OMR prefix can be discovered from Network Data or can be this device's local OMR prefix.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
[out] aPrefix
A pointer to output the favored OMR prefix.
[out] aPreference
A pointer to output the preference associated the favored prefix.
Return Values
OT_ERROR_INVALID_STATE
The Border Routing Manager is not initialized yet.
OT_ERROR_NONE
Successfully retrieved the favored OMR prefix.

otBorderRoutingGetNat64Prefix

otError otBorderRoutingGetNat64Prefix(
  otInstance *aInstance,
  otIp6Prefix *aPrefix
)

Gets the local NAT64 Prefix of the Border Router.

NAT64 Prefix might not be advertised in the Thread network.

OPENTHREAD_CONFIG_BORDER_ROUTING_NAT64_ENABLE must be enabled.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
[out] aPrefix
A pointer to where the prefix will be output to.
Return Values
OT_ERROR_INVALID_STATE
The Border Routing Manager is not initialized yet.
OT_ERROR_NONE
Successfully retrieved the NAT64 prefix.

otBorderRoutingGetNextPrefixTableEntry

otError otBorderRoutingGetNextPrefixTableEntry(
  otInstance *aInstance,
  otBorderRoutingPrefixTableIterator *aIterator,
  otBorderRoutingPrefixTableEntry *aEntry
)

This function iterates over the entries in the Border Router's discovered prefix table.

Details
Parameters
[in] aInstance
The OpenThread instance.
[in,out] aIterator
A pointer to the iterator.
[out] aEntry
A pointer to the entry to populate.
Return Values
OT_ERROR_NONE
Iterated to the next entry, aEntry and aIterator are updated.
OT_ERROR_NOT_FOUND
No more entries in the table.

otBorderRoutingGetOmrPrefix

otError otBorderRoutingGetOmrPrefix(
  otInstance *aInstance,
  otIp6Prefix *aPrefix
)

Gets the local Off-Mesh-Routable (OMR) Prefix, for example fdfc:1ff5:1512:5622::/64.

An OMR Prefix is a randomly generated 64-bit prefix that's published in the Thread network if there isn't already an OMR prefix. This prefix can be reached from the local Wi-Fi or Ethernet network.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
[out] aPrefix
A pointer to where the prefix will be output to.
Return Values
OT_ERROR_INVALID_STATE
The Border Routing Manager is not initialized yet.
OT_ERROR_NONE
Successfully retrieved the OMR prefix.

otBorderRoutingGetOnLinkPrefix

otError otBorderRoutingGetOnLinkPrefix(
  otInstance *aInstance,
  otIp6Prefix *aPrefix
)

Gets the On-Link Prefix for the adjacent infrastructure link, for example fd41:2650:a6f5:0::/64.

An On-Link Prefix is a 64-bit prefix that's advertised on the infrastructure link if there isn't already a usable on-link prefix being advertised on the link.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
[out] aPrefix
A pointer to where the prefix will be output to.
Return Values
OT_ERROR_INVALID_STATE
The Border Routing Manager is not initialized yet.
OT_ERROR_NONE
Successfully retrieved the on-link prefix.

otBorderRoutingGetRouteInfoOptionPreference

otRoutePreference otBorderRoutingGetRouteInfoOptionPreference(
  otInstance *aInstance
)

This function gets the preference used when advertising Route Info Options (e.g., for discovered OMR prefixes) in Router Advertisement messages sent over the infrastructure link.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
Returns
The OMR prefix advertisement preference.

otBorderRoutingInit

otError otBorderRoutingInit(
  otInstance *aInstance,
  uint32_t aInfraIfIndex,
  bool aInfraIfIsRunning
)

This method initializes the Border Routing Manager on given infrastructure interface.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
[in] aInfraIfIndex
The infrastructure interface index.
[in] aInfraIfIsRunning
A boolean that indicates whether the infrastructure interface is running.
Return Values
OT_ERROR_NONE
Successfully started the Border Routing Manager on given infrastructure.
OT_ERROR_INVALID_STATE
The Border Routing Manager has already been initialized.
OT_ERROR_INVALID_ARGS
The index of the infrastructure interface is not valid.
OT_ERROR_FAILED
Internal failure. Usually due to failure in generating random prefixes.
See also:
otPlatInfraIfStateChanged.

otBorderRoutingPrefixTableInitIterator

void otBorderRoutingPrefixTableInitIterator(
  otInstance *aInstance,
  otBorderRoutingPrefixTableIterator *aIterator
)

This function initializes an otBorderRoutingPrefixTableIterator.

An iterator MUST be initialized before it is used.

An iterator can be initialized again to restart from the beginning of the table.

When iterating over entries in the table, to ensure the update times mMsecSinceLastUpdate of entries are consistent, they are given relative to the time the iterator was initialized.

Details
Parameters
[in] aInstance
The OpenThread instance.
[out] aIterator
A pointer to the iterator to initialize.

otBorderRoutingSetEnabled

otError otBorderRoutingSetEnabled(
  otInstance *aInstance,
  bool aEnabled
)

Enables or disables the Border Routing Manager.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
[in] aEnabled
A boolean to enable/disable the routing manager.
Return Values
OT_ERROR_INVALID_STATE
The Border Routing Manager is not initialized yet.
OT_ERROR_NONE
Successfully enabled/disabled the Border Routing Manager.

otBorderRoutingSetRouteInfoOptionPreference

void otBorderRoutingSetRouteInfoOptionPreference(
  otInstance *aInstance,
  otRoutePreference aPreference
)

This function sets the preference to use when advertising Route Info Options in Router Advertisement messages sent over the infrastructure link, for example for discovered OMR prefixes.

By default BR will use medium preference level, but this function allows the default value to be changed. As an example, it can be set to low preference in the case where device is a temporary BR (a mobile BR or a battery-powered BR) to indicate that other BRs (if any) should be preferred over this BR on the infrastructure link.

Details
Parameters
[in] aInstance
A pointer to an OpenThread instance.
[in] aPreference
The route preference to use.

Resources

OpenThread API Reference topics originate from the source code, available on GitHub. For more information, or to contribute to our documentation, refer to Resources.