Update WebRTC candidates logic

internal/ngrok/ngrok.go

@@ -50,7 +50,7 @@ func Init() {
 
 				log.Info().Str("addr", address).Msg("[ngrok] add external candidate for WebRTC")
 
-				webrtc.AddCandidate(address)
+				webrtc.AddCandidate(address, "tcp")
 			}
 		}
 	})

internal/webrtc/README.md

@@ -1,3 +1,17 @@
+## Config
+
+- supported networks: IPv4 (default), IPv6, both
+- supported TCP: fixed port (default), disabled 
+- supported UDP: random port (default), fixed port
+
+| Config examples              | IPv4 | IPv6 | TCP   | UDP    |
+|------------------------------|------|------|-------|--------|
+| `listen: "0.0.0.0:8555/tcp"` | yes  | no   | fixed | random |
+| `listen: "0.0.0.0:8555/udp"` | yes  | no   | no    | fixed  |
+| `listen: "[::]:8555/tcp"`    | no   | yes  | fixed | random |
+| `listen: ":8555"`            | yes  | yes  | fixed | fixed  |
+| `listen: ""`                 | yes  | yes  | no    | random |
+
 ## Userful links
 
 - https://www.ietf.org/archive/id/draft-ietf-wish-whip-01.html

internal/webrtc/candidates.go

@@ -1,58 +1,66 @@
 package webrtc
 
 import (
+	"net"
+
 	"github.com/AlexxIT/go2rtc/internal/api/ws"
 	"github.com/AlexxIT/go2rtc/pkg/webrtc"
 	"github.com/pion/sdp/v3"
-	"strconv"
-	"strings"
 )
 
 type Address struct {
 	Host    string
-	Port int
+	Port    string
+	Network string
+	Offset  int
 }
 
-var addresses []Address
-
-func AddCandidate(address string) {
-	var port int
-
-	// try to get port from address string
-	if i := strings.LastIndexByte(address, ':'); i > 0 {
-		if v, _ := strconv.Atoi(address[i+1:]); v != 0 {
-			address = address[:i]
-			port = v
+func (a *Address) Marshal() string {
+	host := a.Host
+	if host == "stun" {
+		ip, err := webrtc.GetCachedPublicIP()
+		if err != nil {
+			return ""
 		}
+		host = ip.String()
 	}
 
-	// use default WebRTC port
-	if port == 0 {
-		port, _ = strconv.Atoi(Port)
+	switch a.Network {
+	case "udp":
+		return webrtc.CandidateManualHostUDP(host, a.Port, a.Offset)
+	case "tcp":
+		return webrtc.CandidateManualHostTCPPassive(host, a.Port, a.Offset)
 	}
 
-	addresses = append(addresses, Address{Host: address, Port: port})
+	return ""
+}
+
+var addresses []*Address
+
+func AddCandidate(address, network string) {
+	host, port, err := net.SplitHostPort(address)
+	if err != nil {
+		return
+	}
+
+	offset := -1 - len(addresses) // every next candidate will have a lower priority
+
+	switch network {
+	case "tcp", "udp":
+		addresses = append(addresses, &Address{host, port, network, offset})
+	default:
+		addresses = append(
+			addresses, &Address{host, port, "udp", offset}, &Address{host, port, "tcp", offset},
+		)
+	}
 }
 
 func GetCandidates() (candidates []string) {
 	for _, address := range addresses {
-		// using stun server for receive public IP-address
-		if address.Host == "stun" {
-			ip, err := webrtc.GetCachedPublicIP()
-			if err != nil {
-				continue
+		if candidate := address.Marshal(); candidate != "" {
+			candidates = append(candidates, candidate)
 		}
-			// this is a copy, original host unchanged
-			address.Host = ip.String()
 	}
-
-		candidates = append(
-			candidates,
-			webrtc.CandidateManualHostUDP(address.Host, address.Port),
-			webrtc.CandidateManualHostTCPPassive(address.Host, address.Port),
-		)
-	}
-
 	return
 }
 

internal/webrtc/kinesis.go

@@ -55,7 +55,7 @@ func kinesisClient(rawURL string, query url.Values, desc string) (core.Producer,
 	defer conn.Close()
 
 	// 3. Create Peer Connection
-	api, err := webrtc.NewAPI("")
+	api, err := webrtc.NewAPI()
 	if err != nil {
 		return nil, err
 	}

internal/webrtc/openipc.go

@@ -33,7 +33,7 @@ func openIPCClient(rawURL string, query url.Values) (core.Producer, error) {
 	defer conn.Close()
 
 	// 3. Create Peer Connection
-	api, err := webrtc.NewAPI("")
+	api, err := webrtc.NewAPI()
 	if err != nil {
 		return nil, err
 	}

internal/webrtc/webrtc.go

@@ -2,7 +2,7 @@ package webrtc
 
 import (
 	"errors"
-	"net"
+	"strings"
 
 	"github.com/AlexxIT/go2rtc/internal/api"
 	"github.com/AlexxIT/go2rtc/internal/api/ws"
@@ -32,10 +32,20 @@ func Init() {
 
 	log = app.GetLogger("webrtc")
 
-	address := cfg.Mod.Listen
+	address, network, _ := strings.Cut(cfg.Mod.Listen, "/")
+
+	var candidateHost []string
+	for _, candidate := range cfg.Mod.Candidates {
+		if strings.HasPrefix(candidate, "host:") {
+			candidateHost = append(candidateHost, candidate[5:])
+			continue
+		}
+
+		AddCandidate(candidate, network)
+	}
 
 	// create pionAPI with custom codecs list and custom network settings
-	serverAPI, err := webrtc.NewAPI(address)
+	serverAPI, err := webrtc.NewServerAPI(address, network, candidateHost)
 	if err != nil {
 		log.Error().Err(err).Caller().Send()
 		return
@@ -46,9 +56,8 @@ func Init() {
 
 	if address != "" {
 		log.Info().Str("addr", address).Msg("[webrtc] listen")
-		_, Port, _ = net.SplitHostPort(address)
 
-		clientAPI, _ = webrtc.NewAPI("")
+		clientAPI, _ = webrtc.NewAPI()
 	}
 
 	pionConf := pion.Configuration{
@@ -65,10 +74,6 @@ func Init() {
 		}
 	}
 
-	for _, candidate := range cfg.Mod.Candidates {
-		AddCandidate(candidate)
-	}
-
 	// async WebRTC server (two API versions)
 	ws.HandleFunc("webrtc", asyncHandler)
 	ws.HandleFunc("webrtc/offer", asyncHandler)
@@ -81,7 +86,6 @@ func Init() {
 	streams.HandleFunc("webrtc", streamsHandler)
 }
 
-var Port string
 var log zerolog.Logger
 
 var PeerConnection func(active bool) (*pion.PeerConnection, error)

pkg/hass/client.go

@@ -2,10 +2,11 @@ package hass
 
 import (
 	"errors"
+	"net/url"
+
 	"github.com/AlexxIT/go2rtc/pkg/core"
 	"github.com/AlexxIT/go2rtc/pkg/webrtc"
 	pion "github.com/pion/webrtc/v3"
-	"net/url"
 )
 
 type Client struct {
@@ -48,7 +49,7 @@ func NewClient(rawURL string) (*Client, error) {
 	defer hassAPI.Close()
 
 	// 2. Create WebRTC client
-	rtcAPI, err := webrtc.NewAPI("")
+	rtcAPI, err := webrtc.NewAPI()
 	if err != nil {
 		return nil, err
 	}

pkg/nest/client.go

@@ -2,10 +2,11 @@ package nest
 
 import (
 	"errors"
+	"net/url"
+
 	"github.com/AlexxIT/go2rtc/pkg/core"
 	"github.com/AlexxIT/go2rtc/pkg/webrtc"
 	pion "github.com/pion/webrtc/v3"
-	"net/url"
 )
 
 type Client struct {
@@ -34,7 +35,7 @@ func NewClient(rawURL string) (*Client, error) {
 		return nil, err
 	}
 
-	rtcAPI, err := webrtc.NewAPI("")
+	rtcAPI, err := webrtc.NewAPI()
 	if err != nil {
 		return nil, err
 	}

pkg/roborock/client.go

@@ -90,7 +90,7 @@ func (c *Client) Connect() error {
 	}
 
 	// 4. Create Peer Connection
-	api, err := webrtc.NewAPI("")
+	api, err := webrtc.NewAPI()
 	if err != nil {
 		return err
 	}

pkg/webrtc/api.go

@@ -2,9 +2,7 @@ package webrtc
 
 import (
 	"net"
-	"strings"
 
-	"github.com/pion/ice/v2"
 	"github.com/pion/interceptor"
 	"github.com/pion/webrtc/v3"
 )
@@ -13,7 +11,11 @@ import (
 // https://ffmpeg.org/ffmpeg-all.html#Muxer
 const ReceiveMTU = 1472
 
-func NewAPI(address string) (*webrtc.API, error) {
+func NewAPI() (*webrtc.API, error) {
+	return NewServerAPI("", "", nil)
+}
+
+func NewServerAPI(address, network string, candidateHost []string) (*webrtc.API, error) {
 	// for debug logs add to env: `PION_LOG_DEBUG=all`
 	m := &webrtc.MediaEngine{}
 	//if err := m.RegisterDefaultCodecs(); err != nil {
@@ -35,34 +37,33 @@ func NewAPI(address string) (*webrtc.API, error) {
 		return name != "hassio" && name != "docker0"
 	})
 
-	// disable mDNS listener
-	s.SetICEMulticastDNSMode(ice.MulticastDNSModeDisabled)
-
-	// UDP6 may have problems with DNS resolving for STUN servers
-	s.SetNetworkTypes([]webrtc.NetworkType{
-		webrtc.NetworkTypeUDP4, webrtc.NetworkTypeTCP4,
-		webrtc.NetworkTypeUDP6, webrtc.NetworkTypeTCP6,
-	})
-
 	// fix https://github.com/pion/webrtc/pull/2407
 	s.SetDTLSInsecureSkipHelloVerify(true)
 
 	s.SetReceiveMTU(ReceiveMTU)
 
+	s.SetNAT1To1IPs(candidateHost, webrtc.ICECandidateTypeHost)
+
+	// by default enable IPv4 + IPv6 modes
+	s.SetNetworkTypes([]webrtc.NetworkType{
+		webrtc.NetworkTypeUDP4, webrtc.NetworkTypeTCP4,
+		webrtc.NetworkTypeUDP6, webrtc.NetworkTypeTCP6,
+	})
+
 	if address != "" {
-		address, network, _ := strings.Cut(address, "/")
-		if network == "" || network == "udp" {
-			if ln, err := net.ListenPacket("udp", address); err == nil {
-				udpMux := webrtc.NewICEUDPMux(nil, ln)
-				s.SetICEUDPMux(udpMux)
-			}
-		}
 		if network == "" || network == "tcp" {
 			if ln, err := net.Listen("tcp", address); err == nil {
 				tcpMux := webrtc.NewICETCPMux(nil, ln, 8)
 				s.SetICETCPMux(tcpMux)
 			}
 		}
+
+		if network == "" || network == "udp" {
+			if ln, err := net.ListenPacket("udp", address); err == nil {
+				udpMux := webrtc.NewICEUDPMux(nil, ln)
+				s.SetICEUDPMux(udpMux)
+			}
+		}
 	}
 
 	return webrtc.NewAPI(

pkg/webrtc/client_test.go

@@ -10,7 +10,7 @@ import (
 )
 
 func TestClient(t *testing.T) {
-	api, err := NewAPI("")
+	api, err := NewAPI()
 	require.Nil(t, err)
 
 	pc, err := api.NewPeerConnection(webrtc.Configuration{})

pkg/webrtc/helpers.go

@@ -260,17 +260,15 @@ func MimeType(codec *core.Codec) string {
 // for server reflexive candidates, 110 for peer reflexive candidates,
 // and 0 for relayed candidates.
 
-// We use new priority 120 for Manual Host. It is lower than real Host,
-// but more then any other candidates.
+const PriorityTypeHostUDP = (1 << 24) * int(126)
+const PriorityTypeHostTCP = (1 << 24) * int(126-27)
+const PriorityLocalUDP = (1 << 8) * int(65535)
+const PriorityLocalTCPPassive = (1 << 8) * int((1<<13)*4+8191)
+const PriorityComponentRTP = 1 * int(256-ice.ComponentRTP)
 
-const PriorityManualHost = (1 << 24) * uint32(120)
-const PriorityLocalUDP = (1 << 8) * uint32(65535)
-const PriorityLocalTCPPassive = (1 << 8) * uint32((1<<13)*4+8191)
-const PriorityComponentRTP = uint32(256 - ice.ComponentRTP)
-
-func CandidateManualHostUDP(host string, port int) string {
+func CandidateManualHostUDP(host, port string, offset int) string {
 	foundation := crc32.ChecksumIEEE([]byte("host" + host + "udp4"))
-	priority := PriorityManualHost + PriorityLocalUDP + PriorityComponentRTP
+	priority := PriorityTypeHostUDP + PriorityLocalUDP + PriorityComponentRTP + offset
 
 	// 1. Foundation
 	// 2. Component, always 1 because RTP
@@ -279,19 +277,15 @@ func CandidateManualHostUDP(host string, port int) string {
 	// 5. Host - IP4 or IP6 or domain name
 	// 6. Port
 	// 7. typ host
-	return fmt.Sprintf(
-		"candidate:%d 1 udp %d %s %d typ host",
-		foundation, priority, host, port,
-	)
+	return fmt.Sprintf("candidate:%d 1 udp %d %s %s typ host", foundation, priority, host, port)
 }
 
-func CandidateManualHostTCPPassive(address string, port int) string {
-	foundation := crc32.ChecksumIEEE([]byte("host" + address + "tcp4"))
-	priority := PriorityManualHost + PriorityLocalTCPPassive + PriorityComponentRTP
+func CandidateManualHostTCPPassive(host, port string, offset int) string {
+	foundation := crc32.ChecksumIEEE([]byte("host" + host + "tcp4"))
+	priority := PriorityTypeHostTCP + PriorityLocalTCPPassive + PriorityComponentRTP + offset
 
 	return fmt.Sprintf(
-		"candidate:%d 1 tcp %d %s %d typ host tcptype passive",
-		foundation, priority, address, port,
+		"candidate:%d 1 tcp %d %s %s typ host tcptype passive", foundation, priority, host, port,
 	)
 }