utils.go

// Copyright (c) 2017 Che Wei, Lin
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package tinynet

import (
	"net"
)

// https://gist.github.com/kotakanbe/d3059af990252ba89a82
func getAllIPsfromCIDR(cidr string) ([]string, error) {
	ip, ipnet, err := net.ParseCIDR(cidr)
	var ips []string
	if err != nil {
		return nil, err
	}
	for ip := ip.Mask(ipnet.Mask); ipnet.Contains(ip); inc(ip) {
		ips = append(ips, ip.String())
	}
	// remove network address and broadcast address
	return ips[1 : len(ips)-1], nil
}

// http://play.golang.org/p/m8TNTtygK0
func inc(ip net.IP) {
	for j := len(ip) - 1; j >= 0; j-- {
		ip[j]++
		if ip[j] > 0 {
			break
		}
	}
}