bug in NormalExpression evaluation with MPPRFX Objects

Hagen Boehm hboehm at brutus.NIC.DTAG.DE
Tue Apr 3 17:06:12 UTC 2007


Hi all,

recently I triggered a bug in the NormalExpression evaluation process of
RtConfig and peval. Starting RtConfig with the following command

    RtConfig -cisco_use_prefix_lists -cisco_empty_lists -h whois.ripe.net -protocol ripe

and then typing in

    RtConfig> NOT AS25152

leads to an empty prefix set:

Warning: filter "NOT AS25152" matches ANY/NOT ANY
!
no ip prefix-list pl100
ip prefix-list pl100 deny 0.0.0.0/0 le 32

But AS25152 is resolved to a relatively small route-set. Thus its complement
cannot be "NOT ANY"!
 
The bug shows up when a "NOT" is involved and we observed it in many regular
expressions.  

After some tests I found out that this seems to happen only in those cases
where RPSL objects are negated registering ipv4 as well as ipv6 prefixes.

Has anyone triggered this bug too?

When trailing the NormalExpression evaluation process in classes
NormalExpression, NormalTerm, FilterOfPrefix, SetOfPrefix, etc I found two
weird flags:

  "singleton_flag" from NormalExpression and
  "_universal" from SetOfPrefix and SetOfIPv6Prefix respectively.

I could not find any documentation for these flags nor do I have a clear idea
what was/is/should be the intention behind them.

Can anyone tell me more about them? Are they still used as intended?

Thanks a lot!

regards,

     Hagen


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