Add standalone, pure Go port forwarding

net.go

@@ -0,0 +1,54 @@
+/*
+   Copyright 2016-2017 gtalent2@gmail.com
+
+   This Source Code Form is subject to the terms of the Mozilla Public
+   License, v. 2.0. If a copy of the MPL was not distributed with this
+   file, You can obtain one at http://mozilla.org/MPL/2.0/.
+*/
+package main
+
+import (
+	"io"
+	"log"
+	"net"
+)
+
+const (
+	CONN_ACTIVE = iota
+	CONN_DISCONNECTED
+)
+
+type ConnStatus struct {
+	Status int
+	Err    error
+}
+
+func portForward(wanConn *net.TCPConn, lanIp, port string, connStatus chan ConnStatus) {
+	done := make(chan error)
+	log.Print("Proxy: Connecting to ", lanIp+":"+port)
+	lanConn, err := net.Dial("tcp", lanIp+":"+port)
+	if err != nil {
+		log.Print("Proxy: LAN dial error:", err)
+		return
+	}
+
+	go forwardConn(wanConn, lanConn, done)
+	go forwardConn(lanConn, wanConn, done)
+
+	for i := 0; i < 2; i++ {
+		err = <-done
+		if err != nil {
+			log.Print("Proxy:", err)
+		}
+	}
+
+	wanConn.Close()
+	lanConn.Close()
+
+	connStatus <- ConnStatus{Status: CONN_DISCONNECTED, Err: err}
+}
+
+func forwardConn(writer, reader net.Conn, done chan error) {
+	_, err := io.Copy(writer, reader)
+	done <- err
+}

net_freebsd.go

@@ -1,51 +0,0 @@
-/*
-   Copyright 2016-2017 gtalent2@gmail.com
-
-   This Source Code Form is subject to the terms of the Mozilla Public
-   License, v. 2.0. If a copy of the MPL was not distributed with this
-   file, You can obtain one at http://mozilla.org/MPL/2.0/.
-*/
-package main
-
-import (
-	"bytes"
-	"log"
-	"os/exec"
-	"strconv"
-)
-
-func addPortForward(ruleName, ip, port string) {
-	pfrule := "\"rdr pass on $dospin_ext_if proto { tcp, udp } from any to any port {" + port + "} -> " + ip + "\""
-
-	in, err := exec.Command("pfctl", "-a", "\"dospin_"+ruleName+"\"", "-f", "-").StdinPipe()
-	defer in.Close()
-	if err != nil {
-		log.Println("Port Forwarding:", err)
-	}
-
-	_, err = in.Write([]byte(pfrule))
-	if err != nil {
-		log.Println("Port Forwarding:", err)
-	}
-}
-
-func rmPortForward(ruleName string) {
-	_, err := exec.Command("pfctl", "-a", "\"dospin_"+ruleName+"\"", "-F", "rules").Output()
-	if err != nil {
-		log.Println("Port Forwarding:", err)
-	}
-}
-
-func portUsageCount(ports ...int) int {
-	cmd := "sockstat"
-	args := []string{"-4c"}
-	for _, v := range ports {
-		args = append(args, "-p")
-		args = append(args, strconv.Itoa(v))
-	}
-	out, err := exec.Command(cmd, args...).Output()
-	if err != nil {
-		log.Println("Port Usage Check: Could not run \""+cmd+"\":", err)
-	}
-	return bytes.Count(out, []byte{'\n'}) - 1
-}

net_linux.go

@@ -1,32 +0,0 @@
-/*
-   Copyright 2016-2017 gtalent2@gmail.com
-
-   This Source Code Form is subject to the terms of the Mozilla Public
-   License, v. 2.0. If a copy of the MPL was not distributed with this
-   file, You can obtain one at http://mozilla.org/MPL/2.0/.
-*/
-package main
-
-import (
-	"log"
-	"os/exec"
-)
-
-func addPortForward(ruleName, localIp, remoteIp, port string) {
-	log.Println("Setting up port", port, "to", remoteIp)
-	cmdOut, err := exec.Command("iptables", "-t", "nat", "-A", "PREROUTING", "-p", "tcp", "--dport", port, "-j", "DNAT", "--to-destination", remoteIp+":"+port).Output()
-	if err != nil {
-		log.Println("iptables error:", err)
-	}
-	log.Println(cmdOut)
-
-	cmdOut, err = exec.Command("iptables", "-t", "nat", "-A", "POSTROUTING", "-p", "tcp", "-d", localIp, "--dport", port, "-j", "SNAT", "--to-source", remoteIp).Output()
-	if err != nil {
-		log.Println("iptables error:", err)
-	}
-	log.Println("iptables", "-t", "nat", "-A", "POSTROUTING", "-p", "tcp", "-d", localIp, "--dport", port, "-j", "SNAT", "--to-source", remoteIp)
-}
-
-func rmPortForward(ruleName string) {
-	log.Print("Port forwarding not currently implemented for Linux/iptables")
-}

net_test.go

@@ -1,23 +0,0 @@
-/*
-   Copyright 2016-2017 gtalent2@gmail.com
-
-   This Source Code Form is subject to the terms of the Mozilla Public
-   License, v. 2.0. If a copy of the MPL was not distributed with this
-   file, You can obtain one at http://mozilla.org/MPL/2.0/.
-*/
-package main
-
-import (
-	"net"
-	"strconv"
-	"testing"
-)
-
-func TestPortCount(t *testing.T) {
-	port := 49214
-	// listen on some port that nothing should be using for the sake of the test
-	go func() {
-		addr, _ := net.ResolveTCPAddr("tcp", "0.0.0.0:"+strconv.Itoa(port))
-		net.ListenTCP("tcp", addr)
-	}()
-}

servermanager.go

@@ -11,6 +11,7 @@ import (
 	"log"
 	"net"
 	"strconv"
+	"time"
 )
 
 const (
@@ -31,12 +32,14 @@ type ServerHandler interface {
 }
 
 type ServerManager struct {
-	name       string
+	name              string
-	ports      []int
+	ports             []int
-	in         chan serverManagerEvent
+	in                chan serverManagerEvent
-	done       chan interface{}
+	done              chan interface{}
-	usageScore int // spin down server when this reaches 0
+	connStatus        chan ConnStatus
-	server     ServerHandler
+	lastKeepAliveTime time.Time
+	usageScore        int // spin down server when this reaches 0
+	server            ServerHandler
 }
 
 func NewServerManager(name string, server ServerHandler, settings Settings) *ServerManager {
@@ -58,11 +61,22 @@ func NewServerManager(name string, server ServerHandler, settings Settings) *Ser
 func (me *ServerManager) Serve() {
 	// TODO: see if server is currently up, and setup port forwarding if so
 
+	fiveMin := time.Duration(5) * time.Minute
+	ticker := time.NewTicker(fiveMin)
+
 	// event loop
 	for running := true; running; {
 		select {
+		case status := <-me.connStatus:
+			if status.Status == CONN_ACTIVE {
+				me.lastKeepAliveTime = time.Now()
+			}
 		case action := <-me.in:
 			running = me.serveAction(action)
+		case <-ticker.C:
+			if time.Since(me.lastKeepAliveTime) > fiveMin {
+				me.Spindown()
+			}
 		}
 	}
 
@@ -80,7 +94,7 @@ func (me *ServerManager) Spinup(c *net.TCPConn) {
 /*
  Sends the serve loop a spindown message.
 */
-func (me *ServerManager) Spindown(c *net.TCPConn) {
+func (me *ServerManager) Spindown() {
 	me.in <- serverManagerEvent{eventType: SERVERMANAGER_SPINDOWN}
 }
 
@@ -95,18 +109,6 @@ func (me *ServerManager) Done() {
 	<-me.done
 }
 
-func (me *ServerManager) addPortForwards(localIp, remoteIp string) {
-	log.Println("Ports:", me.ports)
-	for _, p := range me.ports {
-		port := strconv.Itoa(p)
-		addPortForward(me.name, localIp, remoteIp, port)
-	}
-}
-
-func (me *ServerManager) rmPortForwards() {
-	rmPortForward(me.name)
-}
-
 func (me *ServerManager) setupListener(port int) {
 	portStr := strconv.Itoa(port)
 	addr, err := net.ResolveTCPAddr("tcp", "0.0.0.0:"+portStr)
@@ -125,14 +127,9 @@ func (me *ServerManager) setupListener(port int) {
 				conn, err := l.AcceptTCP()
 				if err != nil {
 					log.Print("Could not accept TCP connection:", err)
-				} else {
+				} else { // connection accepted
-					// connection accepted
-
 					// spinup machine
 					me.Spinup(conn)
-
-					// close existing connection, not doing anything with it
-					conn.Close()
 				}
 			}
 		}
@@ -146,16 +143,15 @@ func (me *ServerManager) serveAction(event serverManagerEvent) bool {
 		targetIp, err := me.server.Spinup(me.name)
 		if err == nil {
 			log.Println("ServerManager: Got IP for", me.name+":", targetIp)
-			localIp := event.tcpConn.LocalAddr().String()
+			wanAddr := event.tcpConn.LocalAddr().String()
-			me.addPortForwards(localIp, targetIp)
+			_, port, _ := net.SplitHostPort(wanAddr)
+			go portForward(event.tcpConn, targetIp, port, me.connStatus)
 		} else {
 			log.Println("ServerManager: Could not spin up "+me.name+":", err)
 		}
 	case SERVERMANAGER_SPINDOWN:
 		err := me.server.Spindown(me.name)
-		if err == nil {
+		if err != nil {
-			me.rmPortForwards()
-		} else {
 			log.Println("ServerManager: Could not spin down "+me.name+":", err)
 		}
 	case SERVERMANAGER_STOP:

varstate.go

@@ -1,5 +1,5 @@
 /*
-   Copyright 2016 gtalent2@gmail.com
+   Copyright 2016-2017 gtalent2@gmail.com
 
    This Source Code Form is subject to the terms of the Mozilla Public
    License, v. 2.0. If a copy of the MPL was not distributed with this