refs #1976

refs #1976

refs #1976

refs #1976

Added some missing read locks.
TODO: may deadlock somewhere, some functions still find zone from zonedb
and may corrupt new reloaded zone instead of zone the transfer was started

refs #1976

- Returning new node or NULL (if empty) in dname_get_node().
- Modified dname_update_node() to consider empty nodes.
- Freeing empty nodes after everything is finished.
- Marking empty nodes by a new flag.

TSIG is now detected while parsing the RR sections. If it is
there, it is stored in the packet. This also allows for checking
whether TSIG is not in a forbidden place, or whether there is
only one TSIG, etc.

Also removed all TSIG recognition code from other parts of the
server. Not needed anymore.

refs #1522 @1h

- When IXFR is rejected and AXFR is tried, wrong incoming packet
  could have crashed the server. Fixed this by cleaning the
  ns_xfr_t structure before the fallback.

refs #1912

Old: [AI]XFR of 'ZONE/(IN|OUT)' ...
New: (Incoming|Outgoing) [AI]XFR of 'ZONE' ...

refs #1912

refs #1912

- Now should be finally correct. If there is less or more data
  than expected, the packet is treated as malformed.

refs #1910 @1.5h

- Added missing unlock.
- Removed synchonization from dynamic array operation (not needed
  and the dynamic array will be removed anyway).

Some remove/add patterns on iterators are not exactly right,
temporary precautions are implemented.

closes #1795

refs #1807

refs #1799

refs #1799

(as it was delimited by :)

Throttled TCP master doesn't block current connections, so
it is not an issue.

fixes #1542

refs #1542

fixes #1586