Generating HNA

In the configuration file the user specifies the networks that the node should announce itself as a gateway to. These networks are specified by network address and netmask for IPv4, or network address and prefix length for IPv6. If a host is to announce itself as a gateway to the Internet in an IPv4 routed network, the following entry must be added to the configuration file:

HNA4 0.0.0.0 0.0.0.0

For IPv6, Internet gateways would set the following in the configuration file:

HNA6 :: 0

These local entries are kept in a local HNA table which can be updated dynamically at runtime. This way HNA entries to announce can be updated by some extension like explained in section 8.3.2.

A HNA message generation function is registered with the scheduler at startup. If there exist any entry in the local HNA set, HNA messages are generated and transmitted at the given interval. This interval is set to be rather large as default since HNA information is not assumed to be very dynamic. The emission interval can be set by the user in the configuration file. The local HNA set is implemented in src/local_hna_set.c.