This avoids DDoS on the first-in-sequence TCP knockport, which would
otherwise fill up the peer table permanently - especially if the user
does not specify --autoclose - and would thus cause permanent pknock
DoS.
Signed-off-by: Jan Rafaj <jr+netfilter-devel@cedric.unob.cz>
Added the optional "--autoclose" parameter (takes minutes) that
closes the pknock-opened rule in a specified time.
Signed-off-by: Jan Rafaj <jr+netfilter-devel@cedric.unob.cz>
Just below the check that was just removed, the presence of --name is
tested for, as --name is always required. That makes the (flags == 0)
check superfluous, because non-zeroness is ensured by the name check.
In TCP --strict mode, forget the peer which sent the wrong knock in a
sequence, rather than resetting its status to ST_INIT. This avoids
filling up the peer table (which would lead to pknock DoS) in case of
a DDoS attack performed by a set of port-scanning malicious hosts.
