README.md

ipcalc

IP arithmetic utilities for Go, it supports both IPv4/IPv6 addresses.

Installation

go get -u github.com/hazaelsan/ipcalc

Import

import "github.com/hazaelsan/ipcalc"

Package ipcalc

This package provides basic IP arithmetic utilities.

// Get the next IP address
next := ipcalc.NextIP(net.ParseIP("192.0.2.1")) // 192.0.2.2

Note that IP wrapping is entirely possible in most functions

next := ipcalc.NextIP(net.ParseIP("255.255.255.255")) // 0.0.0.0

Package wildcard

This package provides utilities for working with Wildcard Masks, commonly used in Cisco IOS devices.

Wildcard masks are often thought of as "inverse subnet masks", there are some differences:

• Matching logic is reversed from subnet masks, meaning
  • 0 means the equivalent bit must match
  • 1 means the equivalent bit does not matter
• 0s and 1s need not be contiguous

Examples below, format is IP/Wildcard:

• 192.0.2.0/0.0.0.255 matches 192.0.2.*
• 192.0.2.10/0.0.255.0 matches 192.0.*.10
• 192.0.2.1/0.0.255.254 matches 192.0.*.{1,3,5,7,...,255}

Use ipcalc.Complement to convert a subnet mask to its wildcard counterpart.