Introduction
The RouterDiscovery module implements RFC1256 Router Discovery for multiple interfaces as hosts or routers. The action of the RouterDiscovery must be triggered by the user in order to be used. It is expected that address configuration clients will perform this trigger when appropriate. ZeroConf would be expected to trigger RouterDiscovery if no other address has been configured. DHCP would be expected to trigger RouterDiscovery if the relevant options are returned in the DHCP packets from the configuration server.
The module will monitor interface changes and resend solicitations or advertisements as appropriate. Non-availability of the router system is not currently checked for.
Multiple interfaces are supported.
Service calls
| R0 | = | &40 (sub-reason code) | ||||||||
| R1 | = | &B0 (reason code) | ||||||||
| R2 | = | New state:
| ||||||||
| R3 | = | Pointer to zero terminated interface name |
| R1 - R3 | preserved | |
This service call is issued by the RouterDiscovery module when it starts monitoring an interface for router advertisement packets. The module will start by issuing solicitations. Once an advertisement is received the module will modify the default route appropriately.
This service should never be claimed.
| R0 | = | &41 (sub-reason code) | ||||||
| R1 | = | &B0 (reason code) | ||||||
| R2 | = | New state:
| ||||||
| R3 | = | Pointer to zero terminated interface name | ||||||
| R4 | = | Number of routes being advertised | ||||||
| R5 | = | Pointer to router/preference pairs for routers being advertised |
| R1 - R5 | preserved | |
This service call is issued by the RouterDiscovery module when it starts issuing advertisements on an interface. The module will initially issue a few advertisements, before settling into a much more leisurely advertisement every 10 minutes. If a solicitation is received from a host, an advertisement will be made.
This service should never be claimed.
| R0 | = | &42 (sub-reason code) |
| R1 | = | &B0 (reason code) |
| R2 | = | Pointer to zero terminated interface name |
| R3 | = | IP address of gateway through which packets will be routed, or 0 if the default route has been deleted due to non-responsiveness. |
| R1 - R3 | preserved | |
This service call is issued by the RouterDiscovery module when it changes the default route based on information provided from RouterDiscovery operations.
This service should never be claimed.
SWI calls
| R0 | = | Reason code:
|
This SWI is used to control the operation of the RouterDiscovery module.
| R0 | = | 0 (reason code) | ||||||||
| R1 | = | Pointer to zero terminated interface name to activate on | ||||||||
| R2 | = | IPv4 Aaddress to use for solicitations or special value:
|
This SWI is used to allow the RouterDiscovery module to control the operation of an interface as a Host. Solicitations will be sent when the interface changes state and a default route will be configured based on those addresses.
Interface names will not be validated, allowing the interfaces to become available at a future point. Absent interfaces will cause the module to become quiescent until the interfaces become available.
| R0 | = | 1 (reason code) | ||||||||
| R1 | = | Pointer to zero terminated interface name to activate on | ||||||||
| R2 | = | IPv4 Aaddress to use for advertisements or special value:
| ||||||||
| R3 | = | Minimum advertisement interval in seconds, or 0 for default | ||||||||
| R4 | = | Maximum advertisement interval in seconds, or 0 for default | ||||||||
| R5 | = | pointer to a list of router/preference pairs, terminated by a 0 word. A pointer of 0 will mean that the address of the interface will be used, however the interface must be present for this to function. |
This SWI is used to allow the RouterDiscovery module to issue advertisements of router addresses on an interface. Advertisements will be sent regularly, as specified, or when the interface changes state.
Interface names will not be validated unless the pointer in R5 is 0. Absent interfaces will cause the module to become quiescent until the interfaces become available.
| R0 | = | 2 (reason code) |
| R1 | = | Pointer to zero terminated interface name to deactivate |
This SWI is used to stop an interface being monitored by the RouterDiscovery module.
An interface being killed will not implicitly cause this to happen in order that interfaces can be restarted without affecting the operation of RouterDiscovery.
| R0 | = | Reason code (none defined) |
This SWI is not implemented.