- using an isc_task to execute all rndc functions makes it relatively
simple for them to acquire task exclusive mode when needed
- control_recvmessage() has been separated into two functions,
control_recvmessage() and control_respond(). the respond function
can be called immediately from control_recvmessage() when processing
a nonce, or it can be called after returning from the task event
that ran the rndc command function.
- updated libisccc to use netmgr events
- updated rndc to use isc_nm_tcpconnect() to establish connections
- updated control channel to use isc_nm_listentcp()
open issues:
- the control channel timeout was previously 60 seconds, but it is now
overridden by the TCP idle timeout setting, which defaults to 30
seconds. we should add a function that sets the timeout value for
a specific listener socket, instead of always using the global value
set in the netmgr. (for the moment, since 30 seconds is a reasonable
timeout for the control channel, I'm not prioritizing this.)
- the netmgr currently has no support for UNIX-domain sockets; until
this is addressed, it will not be possible to configure rndc to use
them. we will need to either fix this or document the change in
behavior.
