Added c.Listener() which returns a net.Listener.

Likewise, different from David S' implementation.

examples/listener/listener.go

@@ -0,0 +1,51 @@
+// Listener example.
+//
+// To the extent possible under law, Yawning Angel waived all copyright
+// and related or neighboring rights to bulb, using the creative
+// commons "cc0" public domain dedication. See LICENSE or
+// <http://creativecommons.org/publicdomain/zero/1.0/> for full details.
+
+package main
+
+import (
+	"io"
+	"log"
+	"net/http"
+
+	"github.com/yawning/bulb"
+)
+
+func onionServer(w http.ResponseWriter, req *http.Request) {
+	io.WriteString(w, "hello, onion world!\n")
+}
+
+func main() {
+	// Connect to a running tor instance.
+	//  * TCP: c, err := bulb.Dial("tcp4", "127.0.0.1:9051")
+	c, err := bulb.Dial("unix", "/var/run/tor/control")
+	if err != nil {
+		log.Fatalf("failed to connect to control port: %v", err)
+	}
+	defer c.Close()
+
+	// See what's really going on under the hood.
+	// Do not enable in production.
+	c.Debug(true)
+
+	// Authenticate with the control port.  The password argument
+	// here can be "" if no password is set (CookieAuth, no auth).
+	if err := c.Authenticate("ExamplePassword"); err != nil {
+		log.Fatalf("Authentication failed: %v", err)
+	}
+
+	// Create an ephemeral port 80 Onion Service.
+	l, err := c.Listener(80, nil)
+	if err != nil {
+		log.Fatalf("Failed to get Listener: %v", err)
+	}
+	defer l.Close()
+
+	log.Printf("Listener: %s", l.Addr())
+	http.HandleFunc("/", onionServer)
+	http.Serve(l, nil)
+}

listener.go

@@ -0,0 +1,87 @@
+// listener.go - Tor backed net.Listener.
+//
+// To the extent possible under law, Yawning Angel waived all copyright
+// and related or neighboring rights to bulb, using the creative
+// commons "cc0" public domain dedication. See LICENSE or
+// <http://creativecommons.org/publicdomain/zero/1.0/> for full details.
+
+package bulb
+
+import (
+	"crypto"
+	"fmt"
+	"net"
+	"strconv"
+)
+
+type onionAddr struct {
+	info *OnionInfo
+	port uint16
+}
+
+func (a *onionAddr) Network() string {
+	return "tcp"
+}
+
+func (a *onionAddr) String() string {
+	return fmt.Sprintf("%s.onion:%d", a.info.OnionID, a.port)
+}
+
+type onionListener struct {
+	addr     *onionAddr
+	ctrlConn *Conn
+	listener net.Listener
+}
+
+func (l *onionListener) Accept() (net.Conn, error) {
+	return l.listener.Accept()
+}
+
+func (l *onionListener) Close() (err error) {
+	if err = l.listener.Close(); err == nil {
+		// Only delete the onion once.
+		err = l.ctrlConn.DeleteOnion(l.addr.info.OnionID)
+	}
+	return err
+}
+
+func (l *onionListener) Addr() net.Addr {
+	return l.addr
+}
+
+// Listener returns a net.Listener backed by a Onion Service, optionally
+// having Tor generate an ephemeral private key.  Regardless of the status of
+// the returned Listener, the Onion Service will be torn down when the control
+// connection is closed.
+//
+// WARNING: Only one port can be listened to per PrivateKey if this interface
+// is used.  To bind to more ports, use the  AddOnion call directly.
+func (c *Conn) Listener(port uint16, key crypto.PrivateKey) (net.Listener, error) {
+	const (
+		loopbackAddr = "127.0.0.1:0"
+	)
+
+	// Listen on the loopback interface.
+	tcpListener, err := net.Listen("tcp4", loopbackAddr)
+	if err != nil {
+		return nil, err
+	}
+	tAddr, ok := tcpListener.Addr().(*net.TCPAddr)
+	if !ok {
+		tcpListener.Close()
+		return nil, newProtocolError("failed to extract local port")
+	}
+
+	// Create the onion.
+	ports := []OnionPortSpec{{port, strconv.FormatUint((uint64)(tAddr.Port), 10)}}
+	oi, err := c.AddOnion(ports, key, key == nil)
+	if err != nil {
+		tcpListener.Close()
+		return nil, err
+	}
+
+	oa := &onionAddr{info: oi, port: port}
+	ol := &onionListener{addr: oa, ctrlConn: c, listener: tcpListener}
+
+	return ol, nil
+}