Added support for restricting access to exams based on IP addresses.
In order to avoid the problem that students might participate on exams
intended to be held e.g. on campus from at home, one can now restrict
the access based on IP ranges. It is possible to restrict the access
via multiple range blocks that can be predefined by the sysadmins. One
could predefine e.g. IP range blocks for "Campus LAN", "On Site",
"VPN", etc., which can be selected by lecturers for individual exams.
Every IP range block can be defined via multiple entries of disallowed
and allowed IP ranges, where the addresses can be specified via IPv4
or IPv6 CIDR blocks (e.g. 127.208.0.0/16), or with wild cards or
individual IP addresses. The usage of CIDR blocks requires an update
to the updated version of NaviServer.
The IP restriction is used in the current implementation for
restricting the regular start of the exam (proctored or
non-proctored). Lecturers can still perform test runs for exams with
restricted access.
Bump version number to 5.10.1d31
