add ip_retrieval_url.

internal/config/webrtc.go

@@ -1,9 +1,11 @@
 package config
 
 import (
+	"fmt"
 	"strconv"
 	"strings"
 
+	"github.com/rs/zerolog/log"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 
@@ -16,32 +18,44 @@ type WebRTC struct {
 	ICEServers   []string
 	EphemeralMin uint16
 	EphemeralMax uint16
-	NAT1To1IPs   []string
+
+	NAT1To1IPs     []string
+	IpRetrievalUrl string
 }
 
+const (
+	defEprMin = 59000
+	defEprMax = 59100
+)
+
 func (WebRTC) Init(cmd *cobra.Command) error {
-	cmd.PersistentFlags().String("epr", "59000-59100", "limits the pool of ephemeral ports that ICE UDP connections can allocate from")
-	if err := viper.BindPFlag("epr", cmd.PersistentFlags().Lookup("epr")); err != nil {
-		return err
-	}
-
-	cmd.PersistentFlags().StringSlice("nat1to1", []string{}, "sets a list of external IP addresses of 1:1 (D)NAT and a candidate type for which the external IP address is used")
-	if err := viper.BindPFlag("nat1to1", cmd.PersistentFlags().Lookup("nat1to1")); err != nil {
-		return err
-	}
-
 	cmd.PersistentFlags().Bool("icelite", false, "configures whether or not the ice agent should be a lite agent")
 	if err := viper.BindPFlag("icelite", cmd.PersistentFlags().Lookup("icelite")); err != nil {
 		return err
 	}
 
+	cmd.PersistentFlags().Bool("icetrickle", true, "configures whether cadidates should be sent asynchronously using Trickle ICE")
+	if err := viper.BindPFlag("icetrickle", cmd.PersistentFlags().Lookup("icetrickle")); err != nil {
+		return err
+	}
+
 	cmd.PersistentFlags().StringSlice("iceserver", []string{"stun:stun.l.google.com:19302"}, "describes a single STUN and TURN server that can be used by the ICEAgent to establish a connection with a peer")
 	if err := viper.BindPFlag("iceserver", cmd.PersistentFlags().Lookup("iceserver")); err != nil {
 		return err
 	}
 
-	cmd.PersistentFlags().Bool("icetrickle", true, "configures whether cadidates should be sent asynchronously using Trickle ICE")
-	if err := viper.BindPFlag("icetrickle", cmd.PersistentFlags().Lookup("icetrickle")); err != nil {
+	cmd.PersistentFlags().StringSlice("nat1to1", []string{}, "sets a list of external IP addresses of 1:1 (D)NAT and a candidate type for which the external IP address is used")
+	if err := viper.BindPFlag("nat1to1", cmd.PersistentFlags().Lookup("nat1to1")); err != nil {
+		return err
+	}
+
+	cmd.PersistentFlags().String("ip_retrieval_url", "https://checkip.amazonaws.com", "URL address used for retrieval of the external IP address")
+	if err := viper.BindPFlag("ip_retrieval_url", cmd.PersistentFlags().Lookup("ip_retrieval_url")); err != nil {
+		return err
+	}
+
+	cmd.PersistentFlags().String("epr", fmt.Sprintf("%d-%d", defEprMin, defEprMax), "limits the pool of ephemeral ports that ICE UDP connections can allocate from")
+	if err := viper.BindPFlag("epr", cmd.PersistentFlags().Lookup("epr")); err != nil {
 		return err
 	}
 
@@ -52,17 +66,21 @@ func (s *WebRTC) Set() {
 	s.ICELite = viper.GetBool("icelite")
 	s.ICETrickle = viper.GetBool("icetrickle")
 	s.ICEServers = viper.GetStringSlice("iceserver")
-	s.NAT1To1IPs = viper.GetStringSlice("nat1to1")
 
-	if len(s.NAT1To1IPs) == 0 {
-		ip, err := utils.GetIP()
+	s.NAT1To1IPs = viper.GetStringSlice("nat1to1")
+	s.IpRetrievalUrl = viper.GetString("ip_retrieval_url")
+	if s.IpRetrievalUrl != "" && len(s.NAT1To1IPs) == 0 {
+		ip, err := utils.HttpRequestGET(s.IpRetrievalUrl)
 		if err == nil {
 			s.NAT1To1IPs = append(s.NAT1To1IPs, ip)
+		} else {
+			log.Warn().Err(err).Msgf("IP retrieval failed")
 		}
 	}
 
-	min := uint16(59000)
-	max := uint16(59100)
+	min := uint16(defEprMin)
+	max := uint16(defEprMax)
+
 	epr := viper.GetString("epr")
 	ports := strings.SplitN(epr, "-", -1)
 	if len(ports) > 1 {

internal/utils/ip.go

@@ -1,35 +0,0 @@
-package utils
-
-import (
-	"bytes"
-	"io/ioutil"
-	"net/http"
-)
-
-// dig @resolver1.opendns.com ANY myip.opendns.com +short -4
-
-func GetIP() (string, error) {
-	rsp, err := http.Get("http://checkip.amazonaws.com")
-	if err != nil {
-		return "", err
-	}
-	defer rsp.Body.Close()
-
-	buf, err := ioutil.ReadAll(rsp.Body)
-	if err != nil {
-		return "", err
-	}
-
-	return string(bytes.TrimSpace(buf)), nil
-}
-
-func ReadUserIP(r *http.Request) string {
-	IPAddress := r.Header.Get("X-Real-Ip")
-	if IPAddress == "" {
-		IPAddress = r.Header.Get("X-Forwarded-For")
-	}
-	if IPAddress == "" {
-		IPAddress = r.RemoteAddr
-	}
-	return IPAddress
-}

internal/utils/request.go

@@ -0,0 +1,22 @@
+package utils
+
+import (
+	"bytes"
+	"io/ioutil"
+	"net/http"
+)
+
+func HttpRequestGET(url string) (string, error) {
+	rsp, err := http.Get(url)
+	if err != nil {
+		return "", err
+	}
+	defer rsp.Body.Close()
+
+	buf, err := ioutil.ReadAll(rsp.Body)
+	if err != nil {
+		return "", err
+	}
+
+	return string(bytes.TrimSpace(buf)), nil
+}