moved job code from thread_pool to job, jobs have an "execute" method now
added two new jobs: delete_child_sa & rekey_child_sa
kernel interface:
listens now for ACQUIRE & EXPIRE
supports hard and soft lifetimes
fires jobs for delete and rekey child sa
ike sa manager:
can checkout IKE SAs by requid of owned CHILD SAs
we have now the infrastructure to do the rekeying... :-)