Prevent retrying the notify over TCP in case the source address is not
available or the source vs the destination address family mismatch or
when the destination address has been blackholed. Properly log the
hard notify failures.
Add a type to all dns_zone_(get|set) functions that apply to sending
notifies, so the options can be set and retrieved separately per type.
This affects dns_zone_setnotifydefer, dns_zone_getnotifydefer,
dns_zone_setnotifydelay, dns_zone_getnotifydelay,
dns_zone_setnotifysrc4, and dns_zone_setnotifysrc6.
The functions dns_zone_getnotifysrc4 and dns_zone_getnotifysrc6 are
unused and can be removed.
With Generalized DNS Notifications, a zone may need to send different
type of NOTIFY messages for different reasons. When creating a new
notify, allow for specifying the type.
The DSYNC record has a Port rdata field, so NOTIFY(CDS) messages may be
configured at different ports. When creating a new notify, allow for
specifying the port.
With Generalized DNS Notifications, a zone may need to send different
NOTIFY messages for different reasons. Introduce a method to
initialize a notify context and maintain a notify contexts per RRtype.
Maintain the relationship between the parent and child fetch and when
creating a new child fetch, properly check the resolution loops that
would lead to a new fetch would join one of the parent's fetch contexts.
Move dns_notify_destroy, dns_notify_log, dns_notify_cancel,
dns_notify_queue, dns_notify_isqueued, dns_notify_find_address, and
notify related static functions over to the notify source files.
Part of refactoring zone.c is to move the notify code into its own
source files. This commit initiates this work by creating notify.[c,h]
and move notify_create() and the notify state and context there.
The function notify_create() cannot fail, so it can return void instead
of isc_result_t.
