Feature/outbond ip

[jadeydi]

[cedricfung]

This exactly changes the original behavior. I think this change can be applied when neither address nor interface is configured.

So if address use address, then if interface query from interface, otherwise from DNS

[jadeydi]

Fixed

[cedricfung]

Have you tested if this work on some cloud servers? Because I can see we have some pion code using the engine Interface and IP.

[jadeydi]

func GetOutboundIP() {
	log.Println(GetOutboundIP2())
	log.Println(getIPFromInterface())
}

// Get preferred outbound ip of this machine
func GetOutboundIP2() string {
	conn, err := net.Dial("udp", "8.8.8.8:80")
	if err != nil {
		log.Fatal(err)
	}
	defer conn.Close()

	localAddr := conn.LocalAddr().(*net.UDPAddr)

	return localAddr.IP.String()
}

func getIPFromInterface() (string, error) {
	iname := "eth0"

	ifaces, err := net.Interfaces()
	if err != nil {
		return "", err
	}
	for _, i := range ifaces {
		if i.Name != iname {
			continue
		}
		addrs, err := i.Addrs()
		if err != nil {
			return "", err
		}
		for _, addr := range addrs {
			switch v := addr.(type) {
			case *net.IPNet:
				return v.IP.String(), nil
			case *net.IPAddr:
				return v.IP.String(), nil
			}
		}
	}

	return "", fmt.Errorf("no address for interface %s", iname)
}

Tests in Google cloud:

2022/02/22 09:17:09 10.128.x.x 2022/02/22 09:17:09 no address for interface eth0

Tests in Aliyun: 2022/02/22 17:17:27 172.2x.1xx.90 2022/02/22 17:17:27 172.2x.1xx.90

Discussions in stakeoverflow: https://stackoverflow.com/questions/23558425/how-do-i-get-the-local-ip-address-in-go

[cedricfung]

I mean your new modifications, leave interface and address empty.

And for the specific error, that's just because you were not using a correct interface name. Use ip addr to see available interfaces at first.