util/net/cidr/range.go

package cidr

import (
	"fmt"
	"net"
)

func NewCIDRRanger(cidr string) (CIDRRanger, error) {
	_, nIPNet, err := net.ParseCIDR(cidr)
	if nil != err {
		return nil, err
	}

	switch len(nIPNet.IP) {
	case net.IPv4len:
		cr := &cidrRangeIPv4{
			cidrNet: nIPNet,
		}
		return cr, nil
	case net.IPv6len:
		cr := &cidrRangeIPv6{
			cidrNet: nIPNet,
		}
		return cr, nil
	default:
		return nil, fmt.Errorf("Net: not supported IP length")
	}
}

type CIDRRanger interface {
	Contains(ip net.IP) bool
	First() net.IP
	Last() net.IP
	Range(exclude []net.IP) []net.IP
	Broadcast() net.IP
	Network() net.IP
	Next(ip net.IP) net.IP
	Previous(ip net.IP) net.IP
}