feat: add ICE servers and local IP address returned by the API to fix connectivity issues behind NAT

cloud.go

@@ -7,13 +7,14 @@ import (
 	"fmt"
 	"net/http"
 	"net/url"
-	"github.com/coder/websocket/wsjson"
 	"time"
 
+	"github.com/coder/websocket/wsjson"
+
 	"github.com/coreos/go-oidc/v3/oidc"
 
-	"github.com/gin-gonic/gin"
 	"github.com/coder/websocket"
+	"github.com/gin-gonic/gin"
 )
 
 type CloudRegisterRequest struct {
@@ -187,7 +188,7 @@ func handleSessionRequest(ctx context.Context, c *websocket.Conn, req WebRTCSess
 		return fmt.Errorf("google identity mismatch")
 	}
 
-	session, err := newSession()
+	session, err := newSession(req.ICEServers, req.IP)
 	if err != nil {
 		_ = wsjson.Write(context.Background(), c, gin.H{"error": err})
 		return err

config.go

@@ -22,6 +22,7 @@ type Config struct {
 	LocalAuthToken     string            `json:"local_auth_token"`
 	LocalAuthMode      string            `json:"localAuthMode"` //TODO: fix it with migration
 	WakeOnLanDevices   []WakeOnLanDevice `json:"wake_on_lan_devices"`
+	FallbackICEServers []string          `json:"fallback_ice_servers"`
 }
 
 const configPath = "/userdata/kvm_config.json"
@@ -29,6 +30,11 @@ const configPath = "/userdata/kvm_config.json"
 var defaultConfig = &Config{
 	CloudURL:          "https://api.jetkvm.com",
 	AutoUpdateEnabled: true, // Set a default value
+	FallbackICEServers: []string{
+		"stun:stun.cloudflare.com:3478",
+		"stun:stun.cloudflare.com:53",
+		"stun:stun.l.google.com:19302",
+	},
 }
 
 var config *Config

web.go

@@ -19,6 +19,8 @@ var staticFiles embed.FS
 type WebRTCSessionRequest struct {
 	Sd         string   `json:"sd"`
 	OidcGoogle string   `json:"OidcGoogle,omitempty"`
+	IP         string   `json:"ip,omitempty"`
+	ICEServers []string `json:"iceServers,omitempty"`
 }
 
 type SetPasswordRequest struct {
@@ -116,7 +118,7 @@ func handleWebRTCSession(c *gin.Context) {
 		return
 	}
 
-	session, err := newSession()
+	session, err := newSession(nil, "")
 	if err != nil {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": err})
 		return

webrtc.go

@@ -4,6 +4,7 @@ import (
 	"encoding/base64"
 	"encoding/json"
 	"fmt"
+	"net"
 	"strings"
 
 	"github.com/pion/webrtc/v4"
@@ -61,9 +62,23 @@ func (s *Session) ExchangeOffer(offerStr string) (string, error) {
 	return base64.StdEncoding.EncodeToString(localDescription), nil
 }
 
-func newSession() (*Session, error) {
-	peerConnection, err := webrtc.NewPeerConnection(webrtc.Configuration{
-		ICEServers: []webrtc.ICEServer{{}},
+func newSession(iceServers []string, localIP string) (*Session, error) {
+	if iceServers == nil {
+		iceServers = config.FallbackICEServers
+		fmt.Printf("ICE Servers not provided, using fallback %v\n", iceServers)
+	}
+
+	webrtcSettingEngine := webrtc.SettingEngine{}
+	if localIP != "" || net.ParseIP(localIP) == nil {
+		fmt.Printf("Local IP address not provided or invalid, won't set NAT1To1IPs\n")
+	} else {
+		webrtcSettingEngine.SetNAT1To1IPs([]string{localIP}, webrtc.ICECandidateTypeSrflx)
+	}
+
+	// create
+	api := webrtc.NewAPI(webrtc.WithSettingEngine(webrtcSettingEngine))
+	peerConnection, err := api.NewPeerConnection(webrtc.Configuration{
+		ICEServers: []webrtc.ICEServer{{URLs: iceServers}},
 	})
 	if err != nil {
 		return nil, err