subnet-tools

POSIX-compliant shell script library for ip addresses processing, detecting LAN ipv4 and ipv6 subnets and for subnets aggregation.

Included functions:

• ip_to_int()
• int_to_ip()
• hex_to_ipv6()
• aggregate_subnets()
• detect_lan_subnets()
• get_lan_subnets()

Read code comments to find out what each function is doing and how to use it.

Usage

Source the subnet-tools.sh script: . ./subnet-tools.sh

• LAN subnets detection + aggregation:

get_lan_subnets [ipv4|ipv6]

• LAN subnets detection (no aggregation):

detect_lan_subnets [ipv4|ipv6]

• Subnets/ip's aggregation:

Pipe input subnets (newline-separated) into aggregate_subnets. Example:

cat subnets_file.txt | aggregate_subnets [ipv4|ipv6]

Dependencies

• ip utility
• grep, sed, tr and sort.

Notes

• Only use get_lan_subnets() and detect_lan_subnets() on a machine which has no dedicated WAN interfaces (physical or logical). Otherwise WAN subnet may be wrongly detected as LAN subnet.

• The library sets a few variables ($_nl, $subnet_regex_ipv4, $subnet_regex_ipv6) - these are required for some of the functions to work correctly

• The shell code is POSIX-compliant (tested on ash, dash and bash).

• The library avoids using non-POSIX extensions of the aforementioned utilities, except for grep -o which technically is not POSIX-compliant but supported by most grep implementations.

• Tested only on Linux. May or may not work on other UNIX-like operating systems.

P.s.

• If you find any bugs or have a suggestion for code improvement, please let me know.
• If you find this repository useful, please take a second to give it a star.