rus-cert / compress-cidr

Optimize sets of CIDR ranges

Description

Given a set of IP addresses through a list of CIDR ranges, the list of CIDR ranges can grow very big (especially for IPv6), if small (sub)ranges are excluded from the set.

compress-cidr can generate a list of CIDR rules, including and excluding ranges from the set; to check whether a single address is included one needs to take a look at the rule with the longest matching CIDR rule.

compress-cidr can also build the complement of a set, or generate a list of non-overlapping but covering CIDR rules.

Build

compress-cidr is implemented in rust and uses cargo for dependency management.

Run cargo build --release to build it.

Examples

Compress with small sub range excluded

# ./target/release/compress-cidr -6 <<EOF
::/3
4000::/2
8000::/1
EOF

generates

include ::/0
exclude 2000::/3

Generate non-overlapping coverage

# ./target/release/compress-cidr -6 -c <<EOF
::/3
4000::/2
8000::/1
EOF

generates

include ::/3
exclude 2000::/3
include 4000::/2
include 8000::/1

Aggregate list

By creating a non-overlapping coverage and only looking at the include rules one can get an aggregated list:

# ./target/release/compress-cidr -6 -a <<EOF
::/8
100::/8
200::/7
400::/6
800::/5
1000::/4
4000::/2
8000::/1
EOF

produces

::/3
4000::/2
8000::/1