WebRTConn Raw Socket Support

- Use `DataChannelConfig` to specify a raw socket to be used for the Peer Connection.

WebRTConnProcedural.go

@@ -87,7 +87,7 @@ func (c *WebRTConn) Init(dcconfig *DataChannelConfig, pionSettingEngine webrtc.S
 
 	// defer c.lock.Unlock()
 	// c.lock.Lock()
-	err := c.dataChannel.Initialize()
+	err := c.dataChannel.Initialize() // After this line, no change made to pionSettingEngine or pionConfiguration will be effective.
 	if err != nil {
 		return err
 	}

datachannel.go

@@ -31,6 +31,18 @@ func DeclareDatachannel(dcconfig *DataChannelConfig, pionSettingEngine webrtc.Se
 		// WebRTCPeerConnection: nil,
 		// WebRTCDataChannel: nil,
 	}
+
+	if dcconfig.SelfSDPType == "answer" {
+		if dcconfig.AnswererType == "active" {
+			dataChannel.SetDTLSActive()
+		} else if dcconfig.AnswererType == "passive" {
+			dataChannel.SetDTLSPassive()
+		}
+	}
+
+	if dcconfig.RawSocket != nil {
+		dataChannel.UseRawSocket(dcconfig.RawSocket)
+	}
 	return &dataChannel
 }
 

datachannelconfig.go

@@ -1,6 +1,10 @@
 package transportc
 
-import "github.com/pion/webrtc/v3"
+import (
+	"net"
+
+	"github.com/pion/webrtc/v3"
+)
 
 const (
 	DataChannelBufferSizeDefault uint64 = 1024 * 1024 // Default Buffer Size: 1MB
@@ -17,6 +21,10 @@ type DataChannelConfig struct {
 	IPAddr        []string
 	CandidateType webrtc.ICECandidateType
 	Port          uint16
+	AnswererType  string // "active", "passive". Only valid when SelfSDPType == "answer"
+
+	// Enhanced Features Under Test, just wrapper
+	RawSocket *net.UDPConn
 }
 
 func (dcc DataChannelConfig) PeerSDPType() string {

examples/ping-pong-rawsocket/internal/strtool/strtool.go

@@ -0,0 +1,32 @@
+package strtool
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+)
+
+func MustReadStdin() string {
+	r := bufio.NewReader(os.Stdin)
+
+	var in string
+	for {
+		var err error
+		in, err = r.ReadString('\n')
+		if err != io.EOF {
+			if err != nil {
+				panic(err)
+			}
+		}
+		in = strings.TrimSpace(in)
+		if len(in) > 0 {
+			break
+		}
+	}
+
+	fmt.Println("")
+
+	return in
+}

examples/ping-pong-rawsocket/ping/main.go

@@ -0,0 +1,98 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+
+	"github.com/Gaukas/transportc"
+	"github.com/Gaukas/transportc/examples/ping-pong-rawsocket/internal/strtool"
+	"github.com/pion/webrtc/v3"
+)
+
+// ping, a client actively establish the server and
+
+func main() {
+	logger := log.Logger{}
+	logger.SetPrefix("[Logger] ")
+	logger.SetOutput(os.Stdout)
+
+	logger.Println("Dialing to get a WebRTConn struct...")
+	conn, _ := transportc.Dial("udp", "0.0.0.0")
+
+	newDCConfig := transportc.DataChannelConfig{
+		Label:          "Ping-DataChannel",
+		SelfSDPType:    "offer",
+		SendBufferSize: transportc.DataChannelBufferSizeDefault,
+	}
+	newSettingEngine := webrtc.SettingEngine{}
+	newConfiguration := webrtc.Configuration{
+		ICEServers: []webrtc.ICEServer{
+			{
+				URLs: []string{"stun:stun.l.google.com:19302"},
+			},
+		},
+	}
+
+	logger.Println("Initializing WebRTConn instance...")
+	err := conn.Init(&newDCConfig, newSettingEngine, newConfiguration)
+	if err != nil {
+		logger.Panic(err) // Init must not fail. There's no recoverability in a WebRTConn failed to call Init()
+	}
+
+	// Offerer: Show local SDP
+	logger.Println("Acquiring local SDP (offer)...")
+	localSdp, err := conn.LocalSDPJsonString()
+	if err != nil {
+		logger.Panic(err) // If no valid local SDP, you can't establish WebRTC peer connection, and therefore, no datachannel.
+	}
+	logger.Printf("Offer generated as below:\n%s\n", localSdp)
+
+	// Offerer: Wait for remote SDP
+	logger.Println("Ready for Answer...")
+	remoteSdp := strtool.MustReadStdin()
+
+	conn.SetRemoteSDPJsonString(remoteSdp)
+
+	// Block until conn is good to go
+	if (conn.Status() & transportc.WebRTConnReady) == 0 {
+		logger.Println("Waiting for peer...")
+		for (conn.Status() & transportc.WebRTConnReady) == 0 {
+		}
+	}
+	logger.Println("DataChannel established.")
+
+	lastidx := 0
+	for lastidx < 100 {
+		b := []byte(fmt.Sprintf("%d", lastidx))
+		conn.Write(b)
+		// logger.Printf("Ping: %s of size %d\n", string(b), len(b))
+		recv := make([]byte, 10)
+
+		// Block until receive
+		for {
+			n, _ := conn.Read(recv)
+			if n > 0 {
+				clean := []byte{}
+				for _, b := range recv {
+					if b != 0 {
+						clean = append(clean, b)
+					}
+				}
+				recv = clean
+				break
+			}
+		}
+		logger.Printf("Ping: %s of size %d, Pong: %s of size %d\n", string(b), len(b), string(recv), len(recv))
+		idx64, err := strconv.ParseInt(fmt.Sprintf("%s", string(recv)), 10, 64)
+		if err != nil {
+			panic(err)
+		}
+		// logger.Printf("Pong cast to: %d\n", idx64)
+		lastidx = int(idx64) + 1
+	}
+	logger.Println("Closing WebRTConn...")
+	conn.Write([]byte("BYE"))
+	conn.Close()
+}

examples/ping-pong-rawsocket/pong/main.go

@@ -0,0 +1,98 @@
+package main
+
+import (
+	"log"
+	"net"
+	"os"
+
+	"github.com/Gaukas/transportc"
+	"github.com/Gaukas/transportc/examples/ping-pong-rawsocket/internal/strtool"
+	"github.com/pion/webrtc/v3"
+)
+
+// ping, a client actively establish the server and
+
+func main() {
+	logger := log.Logger{}
+	logger.SetPrefix("[Logger] ")
+	logger.SetOutput(os.Stdout)
+
+	logger.Println("Dialing to get a WebRTConn struct...")
+	conn, _ := transportc.Dial("udp", "0.0.0.0")
+
+	udpListener, err := net.ListenUDP("udp", &net.UDPAddr{
+		IP:   net.IP{0, 0, 0, 0},
+		Port: 8563,
+	})
+
+	newDCConfig := transportc.DataChannelConfig{
+		Label:          "Ping-DataChannel",
+		SelfSDPType:    "answer",
+		SendBufferSize: transportc.DataChannelBufferSizeDefault,
+		RawSocket:      udpListener,
+	}
+
+	newSettingEngine := webrtc.SettingEngine{}
+	newConfiguration := webrtc.Configuration{
+		ICEServers: []webrtc.ICEServer{
+			{
+				URLs: []string{"stun:stun.l.google.com:19302"},
+			},
+		},
+	}
+
+	logger.Println("Initializing WebRTConn instance...")
+	err = conn.Init(&newDCConfig, newSettingEngine, newConfiguration)
+	if err != nil {
+		logger.Panic(err) // Init must not fail. There's no recoverability in a WebRTConn failed to call Init()
+	}
+
+	// Answerer: Wait for remote SDP
+	logger.Println("Ready for Offer...")
+	remoteSdp := strtool.MustReadStdin()
+	conn.SetRemoteSDPJsonString(remoteSdp)
+
+	// Offerer: Show local SDP
+	logger.Println("Acquiring local SDP (answer)...")
+	localSdp, err := conn.LocalSDPJsonString()
+	if err != nil {
+		logger.Panic(err) // If no valid local SDP, you can't establish WebRTC peer connection, and therefore, no datachannel.
+	}
+	logger.Printf("Answer generated as below:\n%s\n", localSdp)
+
+	// Block until conn is good to go
+	if (conn.Status() & transportc.WebRTConnReady) == 0 {
+		logger.Println("Waiting for peer...")
+		for (conn.Status() & transportc.WebRTConnReady) == 0 {
+		}
+	}
+	logger.Println("DataChannel established.")
+	for {
+		recv := make([]byte, 10)
+		// Block until receive
+		for {
+			n, _ := conn.Read(recv)
+			if n > 0 {
+				// Copy recv into a "clean" array includes no \x00
+				clean := []byte{}
+				for _, b := range recv {
+					if b != 0 {
+						clean = append(clean, b)
+					}
+				}
+				recv = clean
+				// logger.Printf("Ping: %s of size %d", string(recv), len(recv))
+				break
+			}
+		}
+
+		if string(recv) == "BYE" {
+			logger.Println("Ping: BYE")
+			break
+		} else {
+			// logger.Printf("Pong: %s of size %d", string(recv), len(recv))
+			conn.Write(recv)
+		}
+	}
+	conn.Close()
+}