When the tests-connreset.py module was initially implemented in commit
5c17919019, the dispatch code did not
properly apply the idle timeout to TCP connections. This allowed the
check in that test module to reset the TCP connection after 5 seconds as
named did not attempt to tear the connection down earlier than that.
However, as the dispatch code was improved, the idle timeout started
being enforced for TCP dispatches; the exact value it is set to in the
current code depends on a given server's SRTT, but it defaults to about
1.2 seconds for responsive servers. This means that the code paths
triggered by the "dispatch" system test are now different than the ones
it was originally supposed to trigger because it is now named itself
that shuts the TCP connection down cleanly before the ans3 server gets a
chance to reset it.
Account for the above by lowering the amount of time after which the
ans3 server in the "dispatch" system test resets TCP connections to just
1 second, so that the test actually does what its name implies.
This commit converts the license handling to adhere to the REUSE
specification. It specifically:
1. Adds used licnses to LICENSES/ directory
2. Add "isc" template for adding the copyright boilerplate
3. Changes all source files to include copyright and SPDX license
header, this includes all the C sources, documentation, zone files,
configuration files. There are notes in the doc/dev/copyrights file
on how to add correct headers to the new files.
4. Handle the rest that can't be modified via .reuse/dep5 file. The
binary (or otherwise unmodifiable) files could have license places
next to them in <foo>.license file, but this would lead to cluttered
repository and most of the files handled in the .reuse/dep5 file are
system test files.
The TCP connection reset test starts mock UDP and TCP server which
always returns empty DNS answer with TC bit set over UDP and resets the
TCP connection after five seconds.
When tested without the fix, the DNS query to 10.53.0.2 times out and
the ns2 server hangs at shutdown.
