lancet/netutil/net.go

package netutil

import (
	"encoding/json"
	"io/ioutil"
	"net"
	"net/http"
)

// GetInternalIp return internal ipv4
func GetInternalIp() string {
	addr, err := net.InterfaceAddrs()
	if err != nil {
		panic(err.Error())
	}
	for _, a := range addr {
		if ipNet, ok := a.(*net.IPNet); ok && !ipNet.IP.IsLoopback() {
			if ipNet.IP.To4() != nil {
				return ipNet.IP.String()
			}
		}
	}

	return ""
}

// GetPublicIpInfo return public ip information
// return the PublicIpInfo struct
func GetPublicIpInfo() (*PublicIpInfo, error) {
	resp, err := http.Get("http://ip-api.com/json/")
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}

	var ip PublicIpInfo
	err = json.Unmarshal(body, &ip)
	if err != nil {
		return nil, err
	}

	return &ip, nil
}

// PublicIpInfo public ip info: country, region, isp, city, lat, lon, ip
type PublicIpInfo struct {
	Status      string  `json:"status"`
	Country     string  `json:"country"`
	CountryCode string  `json:"countryCode"`
	Region      string  `json:"region"`
	RegionName  string  `json:"regionName"`
	City        string  `json:"city"`
	Lat         float64 `json:"lat"`
	Lon         float64 `json:"lon"`
	Isp         string  `json:"isp"`
	Org         string  `json:"org"`
	As          string  `json:"as"`
	Ip          string  `json:"query"`
}

// IsPublicIP verify a ip is public or not
func IsPublicIP(IP net.IP) bool {
	if IP.IsLoopback() || IP.IsLinkLocalMulticast() || IP.IsLinkLocalUnicast() {
		return false
	}
	if ip4 := IP.To4(); ip4 != nil {
		switch {
		case ip4[0] == 10:
			return false
		case ip4[0] == 172 && ip4[1] >= 16 && ip4[1] <= 31:
			return false
		case ip4[0] == 192 && ip4[1] == 168:
			return false
		default:
			return true
		}
	}
	return false
}