refactoring of pull 980

follow up on https://github.com/DNSCrypt/dnscrypt-proxy/pull/980#issuecomment-548153169

dnscrypt-proxy/main.go

@@ -8,7 +8,6 @@ import (
 	"math/rand"
 	"os"
 	"os/signal"
-	"sync"
 	"syscall"
 
 	"github.com/facebookgo/pidfile"
@@ -22,8 +21,6 @@ const (
 )
 
 type App struct {
-	wg    sync.WaitGroup
-	quit  chan struct{}
 	proxy *Proxy
 	flags *ConfigFlags
 }
@@ -71,7 +68,6 @@ func main() {
 	}
 
 	app := &App{
-		quit:  make(chan struct{}),
 		flags: &flags,
 	}
 	svc, err := service.New(app, svcConfig)
@@ -101,7 +97,6 @@ func main() {
 		}
 		return
 	}
-	app.wg.Add(1)
 	if svc != nil {
 		if err = svc.Run(); err != nil {
 			dlog.Fatal(err)
@@ -113,7 +108,7 @@ func main() {
 		app.signalWatch()
 		app.Start(nil)
 	}
-	app.wg.Wait()
+	app.proxy.ConnCloseWait()
 	dlog.Notice("Stopped.")
 }
 
@@ -135,14 +130,13 @@ func (app *App) Stop(service service.Service) error {
 		os.Remove(pidFilePath)
 	}
 	dlog.Notice("Quit signal received...")
-	close(app.quit)
+	app.proxy.Stop()
 	return nil
 }
 
 func (app *App) appMain() {
 	pidfile.Write()
-	app.proxy.StartProxy(app.quit)
+	app.proxy.StartProxy()
-	app.wg.Done()
 }
 
 func (app *App) signalWatch() {
@@ -151,6 +145,6 @@ func (app *App) signalWatch() {
 	go func() {
 		<-quit
 		signal.Stop(quit)
-		close(app.quit)
+		app.proxy.Stop()
 	}()
 }

dnscrypt-proxy/proxy.go

@@ -7,6 +7,7 @@ import (
 	"io/ioutil"
 	"net"
 	"os"
+	"sync"
 	"sync/atomic"
 	"time"
 
@@ -72,9 +73,13 @@ type Proxy struct {
 	queryMeta                    []string
 	routes                       *map[string][]string
 	showCerts                    bool
+
+	wg   *sync.WaitGroup
+	quit chan struct{}
 }
 
-func (proxy *Proxy) StartProxy(quit <-chan struct{}) {
+// StartProxy is blocking
+func (proxy *Proxy) StartProxy() {
 	proxy.questionSizeEstimator = NewQuestionSizeEstimator()
 	if _, err := crypto_rand.Read(proxy.proxySecretKey[:]); err != nil {
 		dlog.Fatal(err)
@@ -96,16 +101,12 @@ func (proxy *Proxy) StartProxy(quit <-chan struct{}) {
 
 		// if 'userName' is not set, continue as before
 		if !(len(proxy.userName) > 0) {
-			udpCloser, err := proxy.udpListenerFromAddr(listenUDPAddr)
+			if err := proxy.udpListenerFromAddr(listenUDPAddr); err != nil {
-			if err != nil {
 				dlog.Fatal(err)
 			}
-			tcpCloser, err := proxy.tcpListenerFromAddr(listenTCPAddr)
+			if err := proxy.tcpListenerFromAddr(listenTCPAddr); err != nil {
-			if err != nil {
 				dlog.Fatal(err)
 			}
-			defer udpCloser.Close()
-			defer tcpCloser.Close()
 		} else {
 			// if 'userName' is set and we are the parent process
 			if !proxy.child {
@@ -127,8 +128,13 @@ func (proxy *Proxy) StartProxy(quit <-chan struct{}) {
 				if err != nil {
 					dlog.Fatalf("Unable to switch to a different user: %v", err)
 				}
-				defer listenerUDP.Close()
+				proxy.wg.Add(1)
-				defer listenerTCP.Close()
+				go func() {
+					defer proxy.wg.Done()
+					<-proxy.quit
+					listenerUDP.Close()
+					listenerTCP.Close()
+				}()
 				FileDescriptors = append(FileDescriptors, fdUDP)
 				FileDescriptors = append(FileDescriptors, fdTCP)
 
@@ -148,9 +154,11 @@ func (proxy *Proxy) StartProxy(quit <-chan struct{}) {
 				FileDescriptorNum++
 
 				dlog.Noticef("Now listening to %v [UDP]", listenUDPAddr)
+				proxy.wg.Add(1)
 				go proxy.udpListener(listenerUDP.(*net.UDPConn))
 
 				dlog.Noticef("Now listening to %v [TCP]", listenAddrStr)
+				proxy.wg.Add(1)
 				go proxy.tcpListener(listenerTCP.(*net.TCPListener))
 			}
 		}
@@ -160,11 +168,9 @@ func (proxy *Proxy) StartProxy(quit <-chan struct{}) {
 	if len(proxy.userName) > 0 && !proxy.child {
 		proxy.dropPrivilege(proxy.userName, FileDescriptors)
 	}
-	sdc, err := proxy.SystemDListeners()
+	if err := proxy.SystemDListeners(); err != nil {
-	if err != nil {
 		dlog.Fatal(err)
 	}
-	defer sdc.Close()
 	liveServers, err := proxy.serversInfo.refresh(proxy)
 	if liveServers > 0 {
 		proxy.certIgnoreTimestamp = false
@@ -185,21 +191,18 @@ func (proxy *Proxy) StartProxy(quit <-chan struct{}) {
 	}
 	go proxy.prefetcher()
 	if len(proxy.serversInfo.registeredServers) > 0 {
-		go func() {
+		for {
-			for {
+			delay := proxy.certRefreshDelay
-				delay := proxy.certRefreshDelay
+			if liveServers == 0 {
-				if liveServers == 0 {
+				delay = proxy.certRefreshDelayAfterFailure
-					delay = proxy.certRefreshDelayAfterFailure
-				}
-				clocksmith.Sleep(delay)
-				liveServers, _ = proxy.serversInfo.refresh(proxy)
-				if liveServers > 0 {
-					proxy.certIgnoreTimestamp = false
-				}
 			}
-		}()
+			clocksmith.Sleep(delay)
+			liveServers, _ = proxy.serversInfo.refresh(proxy)
+			if liveServers > 0 {
+				proxy.certIgnoreTimestamp = false
+			}
+		}
 	}
-	<-quit
 }
 
 func (proxy *Proxy) prefetcher() {
@@ -220,6 +223,11 @@ func (proxy *Proxy) prefetcher() {
 }
 
 func (proxy *Proxy) udpListener(clientPc *net.UDPConn) {
+	go func() {
+		defer proxy.wg.Done()
+		<-proxy.quit
+		clientPc.Close()
+	}()
 	for {
 		buffer := make([]byte, MaxDNSPacketSize-1)
 		length, clientAddr, err := clientPc.ReadFrom(buffer)
@@ -239,17 +247,23 @@ func (proxy *Proxy) udpListener(clientPc *net.UDPConn) {
 	}
 }
 
-func (proxy *Proxy) udpListenerFromAddr(listenAddr *net.UDPAddr) (io.Closer, error) {
+func (proxy *Proxy) udpListenerFromAddr(listenAddr *net.UDPAddr) error {
 	clientPc, err := net.ListenUDP("udp", listenAddr)
 	if err != nil {
-		return nil, err
+		return err
 	}
 	dlog.Noticef("Now listening to %v [UDP]", listenAddr)
+	proxy.wg.Add(1)
 	go proxy.udpListener(clientPc)
-	return clientPc, nil
+	return nil
 }
 
 func (proxy *Proxy) tcpListener(acceptPc *net.TCPListener) {
+	go func() {
+		defer proxy.wg.Done()
+		<-proxy.quit
+		acceptPc.Close()
+	}()
 	for {
 		clientPc, err := acceptPc.Accept()
 		if err != nil {
@@ -274,14 +288,15 @@ func (proxy *Proxy) tcpListener(acceptPc *net.TCPListener) {
 	}
 }
 
-func (proxy *Proxy) tcpListenerFromAddr(listenAddr *net.TCPAddr) (io.Closer, error) {
+func (proxy *Proxy) tcpListenerFromAddr(listenAddr *net.TCPAddr) error {
 	acceptPc, err := net.ListenTCP("tcp", listenAddr)
 	if err != nil {
-		return nil, err
+		return err
 	}
 	dlog.Noticef("Now listening to %v [TCP]", listenAddr)
+	proxy.wg.Add(1)
 	go proxy.tcpListener(acceptPc)
-	return acceptPc, nil
+	return nil
 }
 
 func (proxy *Proxy) prepareForRelay(ip net.IP, port int, encryptedQuery *[]byte) {
@@ -510,8 +525,20 @@ func (proxy *Proxy) processIncomingQuery(serverInfo *ServerInfo, clientProto str
 	}
 }
 
+func (proxy *Proxy) Stop() {
+	if proxy.quit != nil {
+		close(proxy.quit)
+	}
+}
+
+func (proxy *Proxy) ConnCloseWait() {
+	proxy.wg.Wait()
+}
+
 func NewProxy() *Proxy {
 	return &Proxy{
 		serversInfo: NewServersInfo(),
+		wg:          new(sync.WaitGroup),
+		quit:        make(chan struct{}),
 	}
 }

dnscrypt-proxy/systemd_android.go

@@ -2,11 +2,6 @@
 
 package main
 
-import (
+func (proxy *Proxy) SystemDListeners() error {
-	"io"
+	return nil
-	"io/ioutil"
-)
-
-func (proxy *Proxy) SystemDListeners() (io.Closer, error) {
-	return ioutil.NopCloser(nil), nil
 }

dnscrypt-proxy/systemd_free.go

@@ -2,11 +2,6 @@
 
 package main
 
-import (
+func (proxy *Proxy) SystemDListeners() error {
-	"io"
+	return nil
-	"io/ioutil"
-)
-
-func (proxy *Proxy) SystemDListeners() (io.Closer, error) {
-	return ioutil.NopCloser(nil), nil
 }

dnscrypt-proxy/systemd_linux.go

@@ -4,23 +4,13 @@ package main
 
 import (
 	"fmt"
-	"io"
 	"net"
 
 	"github.com/coreos/go-systemd/activation"
 	"github.com/jedisct1/dlog"
 )
 
-type multiCloser []io.Closer
+func (proxy *Proxy) SystemDListeners() error {
-
-func (mc multiCloser) Close() (err error) {
-	for _, c := range mc {
-		err = c.Close()
-	}
-	return err
-}
-
-func (proxy *Proxy) SystemDListeners() (io.Closer, error) {
 	files := activation.Files(true)
 
 	if len(files) > 0 {
@@ -29,25 +19,24 @@ func (proxy *Proxy) SystemDListeners() (io.Closer, error) {
 		}
 		dlog.Warn("Systemd sockets are untested and unsupported - use at your own risk")
 	}
-	var mc multiCloser
 	for i, file := range files {
 		defer file.Close()
 		ok := false
 		if listener, err := net.FileListener(file); err == nil {
 			dlog.Noticef("Wiring systemd TCP socket #%d, %s, %s", i, file.Name(), listener.Addr())
 			ok = true
-			mc = append(mc, listener)
+			proxy.wg.Add(1)
 			go proxy.tcpListener(listener.(*net.TCPListener))
 		} else if pc, err := net.FilePacketConn(file); err == nil {
 			dlog.Noticef("Wiring systemd UDP socket #%d, %s, %s", i, file.Name(), pc.LocalAddr())
 			ok = true
-			mc = append(mc, pc)
+			proxy.wg.Add(1)
 			go proxy.udpListener(pc.(*net.UDPConn))
 		}
 		if !ok {
-			return nil, fmt.Errorf("Could not wire systemd socket #%d, %s", i, file.Name())
+			return fmt.Errorf("Could not wire systemd socket #%d, %s", i, file.Name())
 		}
 	}
 
-	return mc, nil
+	return nil
 }