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/*
* Copyright (c) 2014, Yawning Angel <yawning at torproject dot org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* This file is based off goptlib's dummy-server.go file.
*/
// obfs4 pluggable transport server. Works only as a managed proxy.
//
// Usage (in torrc):
// BridgeRelay 1
// ORPort 9001
// ExtORPort 6669
// ServerTransportPlugin obfs4 exec obfs4-server
// ServerTransportOptions obfs4 private-key=<Base64 Bridge private key> node-id=<Base64 Node ID>
//
// Becuase the pluggable transport requires arguments, using obfs4-server
// requires tor 0.2.5.x.
package main
import (
"encoding/hex"
"flag"
"fmt"
"io"
"net"
"os"
"os/signal"
"sync"
"syscall"
"github.com/yawning/obfs4"
"github.com/yawning/obfs4/ntor"
)
import "git.torproject.org/pluggable-transports/goptlib.git"
var ptInfo pt.ServerInfo
// When a connection handler starts, +1 is written to this channel; when it
// ends, -1 is written.
var handlerChan = make(chan int)
func copyLoop(a, b net.Conn) {
var wg sync.WaitGroup
wg.Add(2)
go func() {
io.Copy(b, a)
wg.Done()
}()
go func() {
io.Copy(a, b)
wg.Done()
}()
wg.Wait()
}
func handler(conn net.Conn) error {
defer conn.Close()
handlerChan <- 1
defer func() {
handlerChan <- -1
}()
or, err := pt.DialOr(&ptInfo, conn.RemoteAddr().String(), "obfs4")
if err != nil {
return err
}
defer or.Close()
copyLoop(conn, or)
return nil
}
func acceptLoop(ln net.Listener) error {
defer ln.Close()
for {
conn, err := ln.Accept()
if err != nil {
if e, ok := err.(net.Error); ok && !e.Temporary() {
return err
}
continue
}
go handler(conn)
}
}
func generateParams(id string) {
rawID, err := hex.DecodeString(id)
if err != nil {
fmt.Println("Failed to hex decode id:", err)
return
}
parsedID, err := ntor.NewNodeID(rawID)
if err != nil {
fmt.Println("Failed to parse id:", err)
return
}
fmt.Println("Generated node_id:", parsedID.Base64())
keypair, err := ntor.NewKeypair(false)
if err != nil {
fmt.Println("Failed to generate keypair:", err)
return
}
fmt.Println("Generated private-key:", keypair.Private().Base64())
fmt.Println("Generated public-key:", keypair.Public().Base64())
}
func main() {
var err error
// Some command line args.
genParams := flag.String("gen", "", "Generate params given a Node ID.")
flag.Parse()
if *genParams != "" {
generateParams(*genParams)
os.Exit(0)
}
// Ok, guess we're in PT land.
ptInfo, err = pt.ServerSetup([]string{"obfs4"})
if err != nil {
os.Exit(1)
}
listeners := make([]net.Listener, 0)
for _, bindaddr := range ptInfo.Bindaddrs {
switch bindaddr.MethodName {
case "obfs4":
// Handle the mandetory arguments.
privateKey, ok := bindaddr.Options.Get("private-key")
if !ok {
pt.SmethodError(bindaddr.MethodName, "need a private-key option")
break
}
nodeID, ok := bindaddr.Options.Get("node-id")
if !ok {
pt.SmethodError(bindaddr.MethodName, "need a node-id option")
break
}
ln, err := obfs4.Listen("tcp", bindaddr.Addr.String(), nodeID,
privateKey)
if err != nil {
pt.SmethodError(bindaddr.MethodName, err.Error())
break
}
oLn, _ := ln.(*obfs4.Obfs4Listener)
args := pt.Args{}
args.Add("node-id", nodeID)
args.Add("public-key", oLn.PublicKey())
go acceptLoop(ln)
pt.SmethodArgs(bindaddr.MethodName, ln.Addr(), args)
// TODO: Maybe log the args?
listeners = append(listeners, ln)
default:
pt.SmethodError(bindaddr.MethodName, "no such method")
}
}
pt.SmethodsDone()
var numHandlers int = 0
var sig os.Signal
sigChan := make(chan os.Signal, 1)
signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
// wait for first signal
sig = nil
for sig == nil {
select {
case n := <-handlerChan:
numHandlers += n
case sig = <-sigChan:
}
}
for _, ln := range listeners {
ln.Close()
}
if sig == syscall.SIGTERM {
return
}
// wait for second signal or no more handlers
sig = nil
for sig == nil && numHandlers != 0 {
select {
case n := <-handlerChan:
numHandlers += n
case sig = <-sigChan:
}
}
}
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