Timestamp exchange

The plugin maintains a repository of registered timestamps. Whenever a node receives a packet containing a valid signature message the timestamp repository is searched for a matching entry. If no timestamp entry is registered for the neighbor, the timestamp exchange process is initiated. The timestamp exchange is carried out as explained in 11.3.4. All timestamp messages are broadcasted within regular OLSR packets. These messages uses the generic OLSR message header.

Since an initiator of a timestamp exchange has no timestamp entry registered for the peer node, the timestamp exchange messages must be processed even though regular packets from this host are discarded. This is achieved by checking for timestamp exchange messages prior to the signature verification test. This way timestamp exchange messages are processed even if the OLSR packet is discarded. This is still secure due to the usage of nonces and signatures in the timestamp exchange messages.