Not Perl, though this may be useful depending on your environment:
https://github.com/rus-cert/compress-cidr
The examples are for IPv6, though I use it to consolidate lists of IPv4 in a
variety of jobs/scripts without issue. YMMV.
From: NANOG on behalf of John Von Essen
Sent: Thursday, October 1, 2020 6:32 AM
To: NANOG
Subject: CIDR cleanup
Sorry if this is slightly off-topic, but I am writing some code for a custom
GeoDNS routemap. My starting data set is a raw list of /24 subnets, no prefix
aggregation has been done. In other words, its the entire BGP routing table in
/24 prefixes - tagged by Geo region. Each region is its own txt file with a
dump of /24’s. As a result, these lists are HUGE. I want to aggregate the
prefixes as much as possible to create a smaller routemap.
So right now it looks like:
...
105.170.72.0/24 brs
105.170.73.0/24 brs
105.170.74.0/24 brs
105.170.75.0/24 brs
105.170.76.0/24 brs
105.170.77.0/24 brs
105.170.78.0/24 brs
105.170.79.0/24 brs
105.170.80.0/24 brs
105.170.81.0/24 brs
105.170.82.0/24 brs
105.170.83.0/24 brs
105.170.84.0/24 brs
…
and so on. Obviously, 105.170.72.0/24 thru 105.170.79.0/24 can be aggregated to
105.170.72.0/21 and so on. I normally use Perl, does anyone now if there is a
perl module that will automatically do this prefix aggregation? I tried to
write my code to do this, and its not trivial, just lookinh for a shortcurt. I
did a breif glance at some CIDR related Perl cpan modules, and nothing has
jumped out.
Thanks
John
