Merge pull request #14 from libp2p/example

add an example (mainly for development)

cmd/README.md

+# TLS handshake example
+
+Run
+```bash
+go run cmd/tlsdiag.go server
+```

cmd/tlsdiag.go

+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/libp2p/go-libp2p-tls/cmd/cmdimpl"
+)
+
+func main() {
+	if len(os.Args) <= 1 {
+		fmt.Println("missing argument: client / server")
+		return
+	}
+
+	role := os.Args[1]
+	// remove the role argument from os.Args
+	os.Args = append([]string{os.Args[0]}, os.Args[2:]...)
+
+	var err error
+	switch role {
+	case "client":
+		err = cmdimpl.StartClient()
+	case "server":
+		err = cmdimpl.StartServer()
+	default:
+		fmt.Println("invalid argument. Expected client / server")
+		return
+	}
+	if err != nil {
+		panic(err)
+	}
+}

cmd/tlsdiag/client.go

+package cmdimpl
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"time"
+
+	peer "github.com/libp2p/go-libp2p-peer"
+	libp2ptls "github.com/libp2p/go-libp2p-tls"
+)
+
+func StartClient() error {
+	port := flag.Int("p", 5533, "port")
+	peerIDString := flag.String("id", "", "peer ID")
+	keyType := flag.String("key", "ecdsa", "rsa, ecdsa, ed25519 or secp256k1")
+	flag.Parse()
+
+	priv, err := generateKey(*keyType)
+	if err != nil {
+		return err
+	}
+
+	peerID, err := peer.IDB58Decode(*peerIDString)
+	if err != nil {
+		return err
+	}
+
+	id, err := peer.IDFromPrivateKey(priv)
+	if err != nil {
+		return err
+	}
+	fmt.Printf(" Peer ID: %s\n", id.Pretty())
+	tp, err := libp2ptls.New(priv)
+	if err != nil {
+		return err
+	}
+
+	remoteAddr := fmt.Sprintf("localhost:%d", *port)
+	fmt.Printf("Dialing %s\n", remoteAddr)
+	conn, err := net.Dial("tcp", remoteAddr)
+	if err != nil {
+		return err
+	}
+	fmt.Printf("Dialed raw connection to %s\n", conn.RemoteAddr())
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	sconn, err := tp.SecureOutbound(ctx, conn, peerID)
+	if err != nil {
+		return err
+	}
+	fmt.Printf("Authenticated server: %s\n", sconn.RemotePeer().Pretty())
+	data, err := ioutil.ReadAll(sconn)
+	if err != nil {
+		return err
+	}
+	fmt.Printf("Received message from server: %s\n", string(data))
+	return nil
+}

cmd/tlsdiag/key.go

+package cmdimpl
+
+import (
+	"crypto/rand"
+	"fmt"
+
+	ic "github.com/libp2p/go-libp2p-crypto"
+)
+
+func generateKey(keyType string) (priv ic.PrivKey, err error) {
+	switch keyType {
+	case "rsa":
+		fmt.Printf("Generated new peer with an RSA key.")
+		priv, _, err = ic.GenerateRSAKeyPair(2048, rand.Reader)
+	case "ecdsa":
+		fmt.Printf("Generated new peer with an ECDSA key.")
+		priv, _, err = ic.GenerateECDSAKeyPair(rand.Reader)
+	case "ed25519":
+		fmt.Printf("Generated new peer with an Ed25519 key.")
+		priv, _, err = ic.GenerateEd25519Key(rand.Reader)
+	case "secp256k1":
+		fmt.Printf("Generated new peer with an Secp256k1 key.")
+		priv, _, err = ic.GenerateSecp256k1Key(rand.Reader)
+	default:
+		return nil, fmt.Errorf("unknown key type: %s", keyType)
+	}
+	return
+}

cmd/tlsdiag/server.go

+package cmdimpl
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"net"
+	"time"
+
+	peer "github.com/libp2p/go-libp2p-peer"
+	libp2ptls "github.com/libp2p/go-libp2p-tls"
+)
+
+func StartServer() error {
+	port := flag.Int("p", 5533, "port")
+	keyType := flag.String("key", "ecdsa", "rsa, ecdsa, ed25519 or secp256k1")
+	flag.Parse()
+
+	priv, err := generateKey(*keyType)
+	if err != nil {
+		return err
+	}
+
+	id, err := peer.IDFromPrivateKey(priv)
+	if err != nil {
+		return err
+	}
+	fmt.Printf(" Peer ID: %s\n", id.Pretty())
+	tp, err := libp2ptls.New(priv)
+	if err != nil {
+		return err
+	}
+
+	ln, err := net.Listen("tcp", fmt.Sprintf("localhost:%d", *port))
+	if err != nil {
+		return err
+	}
+	fmt.Printf("Listening for new connections on %s\n", ln.Addr())
+	fmt.Printf("Now run the following command in a separate terminal:\n")
+	fmt.Printf("\tgo run cmd/tlsdiag.go client -p %d -id %s\n", *port, id.Pretty())
+
+	for {
+		conn, err := ln.Accept()
+		if err != nil {
+			return err
+		}
+		fmt.Printf("Accepted raw connection from %s\n", conn.RemoteAddr())
+		go func() {
+			if err := handleConn(tp, conn); err != nil {
+				fmt.Printf("Error handling connection from %s: %s\n", conn.RemoteAddr(), err)
+			}
+		}()
+	}
+}
+
+func handleConn(tp *libp2ptls.Transport, conn net.Conn) error {
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	sconn, err := tp.SecureInbound(ctx, conn)
+	if err != nil {
+		return err
+	}
+	fmt.Printf("Authenticated client: %s\n", sconn.RemotePeer().Pretty())
+	fmt.Fprintf(sconn, "Hello client!")
+	fmt.Printf("Closing connection to %s\n", conn.RemoteAddr())
+	return sconn.Close()
+}