RADIUS server using APM to authenticate users

@Kai : You're right again.

I was working on a simplification / security improvement.

1. check payload length according to RFC

   if {[binary scan [UDP::payload] cH2Sa16 QCODE IDENTIFIER QLEN Q_AUTHENTICATOR] != 4 || $QLEN > [UDP::payload length] || $QLEN > 4096} {
     UDP::drop
     return
   } else {
        Store only PAYLOAD in variable if Length field is valid (less than 4096 and less than payload length). prevent variable allocation if payload not valid.
        Octets outside the range of the Length field MUST be treated as padding and ignored on reception.
       set PAYLOAD [UDP::payload $QLEN]
   }
   

2. create a hash of payload to manage "Duplicate Detection"

   I was thinking to store payload md5 hash as session variable key (one subtable per IP address) with response payload in value and with 30s timeout.