private-ip.go

/*
 * Copyright (c) 2019. Abstrium SAS <team (at) pydio.com>
 * This file is part of Pydio Cells.
 *
 * Pydio Cells is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Pydio Cells is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with Pydio Cells.  If not, see <http://www.gnu.org/licenses/>.
 *
 * The latest code can be found at <https://pydio.com>.
 */

package net

import (
	"fmt"
	"net"
)

var (
	privateBlocks           []*net.IPNet
	DefaultAdvertiseAddress string
)

func init() {
	for _, b := range []string{"10.0.0.0/8", "172.16.0.0/12", "192.168.0.0/16"} {
		if _, block, err := net.ParseCIDR(b); err == nil {
			privateBlocks = append(privateBlocks, block)
		}
	}
}

func DetectHasPrivateIP() (bool, string, error) {

	addrs, err := net.InterfaceAddrs()
	if err != nil {
		return false, "", fmt.Errorf("Failed to get interface addresses! Err: %v", err)
	}

	var ipAddr []byte

	for _, rawAddr := range addrs {
		var ip net.IP
		switch addr := rawAddr.(type) {
		case *net.IPAddr:
			ip = addr.IP
		case *net.IPNet:
			ip = addr.IP
		default:
			continue
		}

		if ip.To4() == nil {
			continue
		}

		ipAddr = ip

		if isPrivateIP(ip.String()) {
			return true, "", nil
		}
	}

	if ipAddr == nil {
		return false, "", fmt.Errorf("could not find any suitable IP for binding broker")
	}

	return false, net.IP(ipAddr).String(), nil
}

func isPrivateIP(ipAddr string) bool {
	ip := net.ParseIP(ipAddr)
	for _, priv := range privateBlocks {
		if priv.Contains(ip) {
			return true
		}
	}
	return false
}