rediswho and Simultaneous-Use

[Nitzan Tzelniker]

I’m working on implementing a Simultaneous-Use check using the
rediswho module in the FreeRADIUS 3.2 branch.
The approach is inspired by the blog post “Preventing Fraudulent
Logins with a Session Database” (which unfortunately appears to be
offline).

At this stage, I’m successfully writing accounting records into Redis
through rediswho. However, I haven’t found any documentation or
examples describing how to query Redis for Simultaneous-Use checking
and verification — specifically, the equivalent of the
simul_count_query and simul_verify_query mechanisms used in the SQL
module

If anyone has implemented this or can provide guidance on best
practices for performing Simultaneous-Use checks with rediswho, I
would appreciate any insights or references.

Additionally, I noticed that the default rediswho configuration in
both versions 3.2 and 4.0 uses the same insert operation for all
Acct-Status-Type values. As a result, when querying the Redis, it’s
not possible to distinguish between sessions that have terminated with
an Acct-Status-Type = Stop and those that are still active.

Nitzan