undid some redundant code and removed most work setting up a tun device

main.go

@@ -1,16 +1,21 @@
 package main
 
 import (
-    "bufio"
+//    "bufio"
     "fmt"
     "log"
     "os"
-//	"time"
+	"net"
 	"strconv"
-
+	"io"
+	"context"
+	"time"
 	"math/rand"
+	"bytes"
 
-	"github.com/songgao/packets/ethernet"
+	"golang.org/x/crypto/ssh"
+
+//	"github.com/songgao/packets/ethernet"
 	"github.com/songgao/water"
 
     "github.com/vishvananda/netlink"
@@ -20,6 +25,7 @@ type Client struct {
 	ifce *water.Interface
 	hostname string
 	addr *netlink.Addr
+	addr_str string
 }
 
 // -- funcs --
@@ -47,6 +53,17 @@ type Client struct {
 // used to verify collisions
 var client_leases = make(map[string]string)
 
+var mode string
+func detectMode() {
+	mode = os.Getenv("LAZYVPN_MODE")
+	if len(mode) == 0 {
+		fmt.Println("Mode not set! assuming CLIENT")
+		mode = "CLIENT"
+	}
+	fmt.Printf("Running in mode %s\n", mode)
+	return 
+}
+
 func generateClientTUN(hn string) Client {
 
 	// configure TUN interface	
@@ -63,24 +80,28 @@ func generateClientTUN(hn string) Client {
 
 	// Generate a free address to assign
 	var cl_Addr_str string
+	if mode == "CLIENT" {
+		// This is a bad way of doing it, and only accounts for local conflicts
+		// theres definitely a way to find if it conflicts somewhere else
+		// ideally, it shouldnt be locked to this 16 block, either. eventually,
+		// the allowed range (CIDR included) should be defined.
+		// this is an alpha for now, just to get *something* nice working	
+		r := rand.New(rand.NewSource(255))
+		for {
+			var b1 int = int(r.Int31n(255))	
+			var b2 int = int(r.Int31n(255))
+			cl_Addr_str = "." + strconv.Itoa(b1) + "." + strconv.Itoa(b2)
 
-	// This is a bad way of doing it, and only accounts for local conflicts
-	// theres definitely a way to find if it conflicts somewhere else
-	// ideally, it shouldnt be locked to this 16 block, either. eventually,
-	// the allowed range (CIDR included) should be defined.
-	// this is an alpha for now, just to get *something* nice working	
-	r := rand.New(rand.NewSource(255))
-	for {
-		var b1 int = int(r.Int31n(255))	
-		var b2 int = int(r.Int31n(255))
-		cl_Addr_str = "." + strconv.Itoa(b1) + "." + strconv.Itoa(b2)
+			fmt.Println(cl_Addr_str)
 
-		fmt.Println(cl_Addr_str)
-
-		_, isLeased := client_leases[cl_Addr_str]
-		if !isLeased {
-			break
+			_, isLeased := client_leases[cl_Addr_str]
+			if !isLeased {
+				break
+			}
 		}
+	} else {
+		// its the server
+		cl_Addr_str = ".0.1"
 	}
 
 	cl_Link, err := netlink.LinkByName(config.Name)
@@ -88,7 +109,8 @@ func generateClientTUN(hn string) Client {
 		log.Fatal(err)
 	}
 
-	cl_Addr, err := netlink.ParseAddr("169.254"+cl_Addr_str+"/16")
+	cl_Addr_str = "169.254"+cl_Addr_str
+	cl_Addr, err := netlink.ParseAddr(cl_Addr_str+"/16")
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -100,40 +122,87 @@ func generateClientTUN(hn string) Client {
 		ifce: cl_ifce,
 		hostname: hn,
 		addr: cl_Addr,
+		addr_str: cl_Addr_str,
+	}
+}
+
+func StartListener(addr string) {
+	// listen on port 28173
+	l, err := net.Listen("tcp", addr+":28173")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer l.Close()
+	
+	fmt.Printf("Listening on %s port 28173", addr)
+
+	for {
+		// Wait for a connection.
+		conn, err := l.Accept()
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		// Handle the connection in a new goroutine.
+		// The loop then returns to accepting, so that
+		// multiple connections may be served concurrently.
+		go func(c net.Conn) {
+			// Echo all incoming data.
+			io.Copy(c, c)
+			// Shut down the connection.
+			c.Close()
+		}(conn)
+	}
+}
+
+func StartDialer() {
+	var d net.Dialer
+	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+	defer cancel()
+
+	fmt.Printf("Attempting autodiscovery")
+	conn, err := d.DialContext(ctx, "tcp", "169.254.0.1:28173")
+	if err != nil {
+		log.Fatalf("Failed to dial: %v", err)
+	}
+	defer conn.Close()
+
+	if _, err := conn.Write([]byte("Hello, World!")); err != nil {
+		log.Fatal(err)
 	}
 }
 
 func main() {
-	var desired_hostname string
-	fmt.Printf("your nosthanem is ")
-	hn, _ := os.Hostname()
-	fmt.Println(hn)
-	fmt.Printf("Please enter a desired hostname for the new client: ")
+	// Detect if we are in CLIENT or SERVER mode
+	detectMode()
 	
-    scanner := bufio.NewScanner(os.Stdin)
-    scanner.Scan()
-    err := scanner.Err()
-    if err != nil {
-        log.Fatal(err)
-	}
-	desired_hostname = scanner.Text()
-	var registered_client Client = generateClientTUN(desired_hostname)
-	log.Printf("interface name: %s\n", registered_client.ifce.Name())
+	// Zeroth stage - gather info
+	var hostKey ssh.PublicKey
 	
-	var frame ethernet.Frame
-	ifce := registered_client.ifce
-	for {
-		frame.Resize(1500)
-		n, err := ifce.Read([]byte(frame))
-		if err != nil {
-			log.Fatal(err)
-		}
-		frame = frame[:n]
-		log.Printf("Dst: %s\n", frame.Destination())
-		log.Printf("Src: %s\n", frame.Source())
-		log.Printf("Ethertype: % x\n", frame.Ethertype())
-		log.Printf("Payload: % x\n", frame.Payload())
+
+	config := &ssh.ClientConfig {
+		User: os.Getenv("LAZYUSER"),
+		Auth: []ssh.authmethod {
+			ssh.Password(os.Getenv("LAZYPASS")),
+		},
+		HostKeyCallback: ssh.FixedHostKey(hostKey),
 	}
 
-//	generateNewClient()
+	// First stage - attempt to connect to public host
+	var host string = "192.168.122.1"
+	fmt.Printf("Dialing host %s....\n", host)
+	client, err := ssh.Dial("tcp", host+":22278", config)
+	if err != nil {
+		log.Fatal("Failed to dial: ", err)
+	}
+	defer client.Close()
+
+	// Final stage
+	if mode == "SERVER" {
+		// open, listen and wait
+		StartListener(registered_client.addr_str)
+	} else {
+		// connect to far end
+		StartDialer()
+	}
 }