Quagga Graceful Restart

Graceful Restart support is added to quagga as specified in RFC 3623. Both the restart mode and helper mode support is added.

Configuration available The following configurations are available under the router ospf/graceful restart node. disable disabling the status enable Enabling the status helper-disable disabling the support helper-enable enabling the support helper-strict-lsa-checking Restart helper-strict-lsa-checking option no-strict-lsa-checking Disabling helper-strict-lsa-checking option reason Restart Reason restart-duration Restart interval time

The graceful helper mode holds the adjaceny of the gracefully restarting neighbour till the grace period expires.

The gracefully restarting router informs the peers the reason for the graceful restart,the grace period, to the peer using the type 9 opqaue lsas. When the router restarts successfully again it flushes the grace-lsa such that the adjacent routers can exit helper mode.

The patch is taken from the Quagga version 0.99.24.1 as base.