"Module ... became unblocked" after FR30 upgrade

[Jakob Hirsch]

A.L.M.Buxey at lboro.ac.uk wrote on 2016-06-21 16:58:
>> I'm getting lots of this since upgrading from 2.2.9 to 3.0.11:

Ok, probably found the cause: A radius client (RADIUS proxy from one of
the wholesale providers we use) sometimes sends two consecutive
accounting requests with the same request id (and from the source
ip/port), so FR ignores the second request as a duplicate and won't send
an Accounting-Response. The log message then looks like this:

> Error: Received conflicting packet from client xxxx_acct3 port 20001 - ID: 143 due to unfinished request.  Giving up on old request.
> WARNING: (3134530) WARNING: Module rlm_preprocess became unblocked for request 3134530

Strangely, I don't get the "Module ... became unblocked" for _all_ of
these false duplicates, but _every_ "became unblocked" log entry is
preceded by "Error: Received conflicting packet...".

Obviously, this is bad and wrong behaviour of the radius client, so I'll
try to get them to fix this.

> preprocess getting blocked? hmmm, using huntgroups or hints or using some 
> random other thing in preprocess?

preprocess is only used for the huntgroups file, which has only about 45
entries, mostly matching on Client-IP-Address, so this really should not
cause trouble.

The warnings really looked alarming at first, and I'd really like to
know what's happening there, even though they do not seem to do any
trouble...