TUN-528: Move cloudflared into a separate repo

tunneldns/tunnel.go

@@ -0,0 +1,148 @@
+package tunneldns
+
+import (
+	"net"
+	"os"
+	"os/signal"
+	"strconv"
+	"sync"
+	"syscall"
+
+	"github.com/cloudflare/cloudflared/log"
+	"github.com/cloudflare/cloudflared/metrics"
+
+	"github.com/coredns/coredns/core/dnsserver"
+	"github.com/coredns/coredns/plugin"
+	"github.com/coredns/coredns/plugin/cache"
+	"github.com/pkg/errors"
+	"gopkg.in/urfave/cli.v2"
+)
+
+var logger = log.CreateLogger()
+
+// Listener is an adapter between CoreDNS server and Warp runnable
+type Listener struct {
+	server *dnsserver.Server
+	wg     sync.WaitGroup
+}
+
+// Run implements a foreground runner
+func Run(c *cli.Context) error {
+	metricsListener, err := net.Listen("tcp", c.String("metrics"))
+	if err != nil {
+		logger.WithError(err).Fatal("Failed to open the metrics listener")
+	}
+
+	go metrics.ServeMetrics(metricsListener, nil, logger)
+
+	listener, err := CreateListener(c.String("address"), uint16(c.Uint("port")), c.StringSlice("upstream"))
+	if err != nil {
+		logger.WithError(err).Errorf("Failed to create the listeners")
+		return err
+	}
+
+	// Try to start the server
+	readySignal := make(chan struct{})
+	err = listener.Start(readySignal)
+	if err != nil {
+		logger.WithError(err).Errorf("Failed to start the listeners")
+		return listener.Stop()
+	}
+	<-readySignal
+
+	// Wait for signal
+	signals := make(chan os.Signal, 10)
+	signal.Notify(signals, syscall.SIGTERM, syscall.SIGINT)
+	defer signal.Stop(signals)
+	<-signals
+
+	// Shut down server
+	err = listener.Stop()
+	if err != nil {
+		logger.WithError(err).Errorf("failed to stop")
+	}
+	return err
+}
+
+// Create a CoreDNS server plugin from configuration
+func createConfig(address string, port uint16, p plugin.Handler) *dnsserver.Config {
+	c := &dnsserver.Config{
+		Zone:        ".",
+		Transport:   "dns",
+		ListenHosts: []string{address},
+		Port:        strconv.FormatUint(uint64(port), 10),
+	}
+
+	c.AddPlugin(func(next plugin.Handler) plugin.Handler { return p })
+	return c
+}
+
+// Start blocks for serving requests
+func (l *Listener) Start(readySignal chan struct{}) error {
+	defer close(readySignal)
+	logger.WithField("addr", l.server.Address()).Infof("Starting DNS over HTTPS proxy server")
+
+	// Start UDP listener
+	if udp, err := l.server.ListenPacket(); err == nil {
+		l.wg.Add(1)
+		go func() {
+			l.server.ServePacket(udp)
+			l.wg.Done()
+		}()
+	} else {
+		return errors.Wrap(err, "failed to create a UDP listener")
+	}
+
+	// Start TCP listener
+	tcp, err := l.server.Listen()
+	if err == nil {
+		l.wg.Add(1)
+		go func() {
+			l.server.Serve(tcp)
+			l.wg.Done()
+		}()
+	}
+
+	return errors.Wrap(err, "failed to create a TCP listener")
+}
+
+// Stop signals server shutdown and blocks until completed
+func (l *Listener) Stop() error {
+	if err := l.server.Stop(); err != nil {
+		return err
+	}
+
+	l.wg.Wait()
+	return nil
+}
+
+// CreateListener configures the server and bound sockets
+func CreateListener(address string, port uint16, upstreams []string) (*Listener, error) {
+	// Build the list of upstreams
+	upstreamList := make([]Upstream, 0)
+	for _, url := range upstreams {
+		logger.WithField("url", url).Infof("Adding DNS upstream")
+		upstream, err := NewUpstreamHTTPS(url)
+		if err != nil {
+			return nil, errors.Wrap(err, "failed to create HTTPS upstream")
+		}
+		upstreamList = append(upstreamList, upstream)
+	}
+
+	// Create a local cache with HTTPS proxy plugin
+	chain := cache.New()
+	chain.Next = ProxyPlugin{
+		Upstreams: upstreamList,
+	}
+
+	// Format an endpoint
+	endpoint := "dns://" + net.JoinHostPort(address, strconv.FormatUint(uint64(port), 10))
+
+	// Create the actual middleware server
+	server, err := dnsserver.NewServer(endpoint, []*dnsserver.Config{createConfig(address, port, NewMetricsPlugin(chain))})
+	if err != nil {
+		return nil, err
+	}
+
+	return &Listener{server: server}, nil
+}