/* * Copyright (c) 2014-2015, Yawning Angel * 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. */ // Go language Tor Pluggable Transport suite. Works only as a managed // client/server. package main import ( "flag" "fmt" "io" golog "log" "net" "net/url" "os" "path" "sync" "syscall" "golang.org/x/net/proxy" "git.torproject.org/pluggable-transports/goptlib.git" "git.torproject.org/pluggable-transports/obfs4.git/common/log" "git.torproject.org/pluggable-transports/obfs4.git/common/socks5" "git.torproject.org/pluggable-transports/obfs4.git/transports" "git.torproject.org/pluggable-transports/obfs4.git/transports/base" ) const ( obfs4proxyVersion = "0.0.6-dev" obfs4proxyLogFile = "obfs4proxy.log" socksAddr = "127.0.0.1:0" ) var stateDir string var termMon *termMonitor func clientSetup() (launched bool, listeners []net.Listener) { ptClientInfo, err := pt.ClientSetup(transports.Transports()) if err != nil { golog.Fatal(err) } ptClientProxy, err := ptGetProxy() if err != nil { golog.Fatal(err) } else if ptClientProxy != nil { ptProxyDone() } // Launch each of the client listeners. for _, name := range ptClientInfo.MethodNames { t := transports.Get(name) if t == nil { pt.CmethodError(name, "no such transport is supported") continue } f, err := t.ClientFactory(stateDir) if err != nil { pt.CmethodError(name, "failed to get ClientFactory") continue } ln, err := net.Listen("tcp", socksAddr) if err != nil { pt.CmethodError(name, err.Error()) continue } go clientAcceptLoop(f, ln, ptClientProxy) pt.Cmethod(name, socks5.Version(), ln.Addr()) log.Infof("%s - registered listener: %s", name, ln.Addr()) listeners = append(listeners, ln) launched = true } pt.CmethodsDone() return } func clientAcceptLoop(f base.ClientFactory, ln net.Listener, proxyURI *url.URL) 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 clientHandler(f, conn, proxyURI) } } func clientHandler(f base.ClientFactory, conn net.Conn, proxyURI *url.URL) { defer conn.Close() termMon.onHandlerStart() defer termMon.onHandlerFinish() name := f.Transport().Name() // Read the client's SOCKS handshake. socksReq, err := socks5.Handshake(conn) if err != nil { log.Errorf("%s - client failed socks handshake: %s", name, err) return } addrStr := log.ElideAddr(socksReq.Target) // Deal with arguments. args, err := f.ParseArgs(&socksReq.Args) if err != nil { log.Errorf("%s(%s) - invalid arguments: %s", name, addrStr, err) socksReq.Reply(socks5.ReplyGeneralFailure) return } // Obtain the proxy dialer if any, and create the outgoing TCP connection. dialFn := proxy.Direct.Dial if proxyURI != nil { dialer, err := proxy.FromURL(proxyURI, proxy.Direct) if err != nil { // This should basically never happen, since config protocol // verifies this. log.Errorf("%s(%s) - failed to obtain proxy dialer: %s", name, addrStr, log.ElideError(err)) socksReq.Reply(socks5.ReplyGeneralFailure) return } dialFn = dialer.Dial } remote, err := f.Dial("tcp", socksReq.Target, dialFn, args) if err != nil { log.Errorf("%s(%s) - outgoing connection failed: %s", name, addrStr, log.ElideError(err)) socksReq.Reply(socks5.ErrorToReplyCode(err)) return } defer remote.Close() err = socksReq.Reply(socks5.ReplySucceeded) if err != nil { log.Errorf("%s(%s) - SOCKS reply failed: %s", name, addrStr, log.ElideError(err)) return } if err = copyLoop(conn, remote); err != nil { log.Warnf("%s(%s) - closed connection: %s", name, addrStr, log.ElideError(err)) } else { log.Infof("%s(%s) - closed connection", name, addrStr) } return } func serverSetup() (launched bool, listeners []net.Listener) { ptServerInfo, err := pt.ServerSetup(transports.Transports()) if err != nil { golog.Fatal(err) } for _, bindaddr := range ptServerInfo.Bindaddrs { name := bindaddr.MethodName t := transports.Get(name) if t == nil { pt.SmethodError(name, "no such transport is supported") continue } f, err := t.ServerFactory(stateDir, &bindaddr.Options) if err != nil { pt.SmethodError(name, err.Error()) continue } ln, err := net.ListenTCP("tcp", bindaddr.Addr) if err != nil { pt.SmethodError(name, err.Error()) continue } go serverAcceptLoop(f, ln, &ptServerInfo) if args := f.Args(); args != nil { pt.SmethodArgs(name, ln.Addr(), *args) } else { pt.SmethodArgs(name, ln.Addr(), nil) } log.Infof("%s - registered listener: %s", name, log.ElideAddr(ln.Addr().String())) listeners = append(listeners, ln) launched = true } pt.SmethodsDone() return } func serverAcceptLoop(f base.ServerFactory, ln net.Listener, info *pt.ServerInfo) 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 serverHandler(f, conn, info) } } func serverHandler(f base.ServerFactory, conn net.Conn, info *pt.ServerInfo) { defer conn.Close() termMon.onHandlerStart() defer termMon.onHandlerFinish() name := f.Transport().Name() addrStr := log.ElideAddr(conn.RemoteAddr().String()) log.Infof("%s(%s) - new connection", name, addrStr) // Instantiate the server transport method and handshake. remote, err := f.WrapConn(conn) if err != nil { log.Warnf("%s(%s) - handshake failed: %s", name, addrStr, log.ElideError(err)) return } // Connect to the orport. orConn, err := pt.DialOr(info, conn.RemoteAddr().String(), name) if err != nil { log.Errorf("%s(%s) - failed to connect to ORPort: %s", name, addrStr, log.ElideError(err)) return } defer orConn.Close() if err = copyLoop(orConn, remote); err != nil { log.Warnf("%s(%s) - closed connection: %s", name, addrStr, log.ElideError(err)) } else { log.Infof("%s(%s) - closed connection", name, addrStr) } return } func copyLoop(a net.Conn, b net.Conn) error { // Note: b is always the pt connection. a is the SOCKS/ORPort connection. errChan := make(chan error, 2) var wg sync.WaitGroup wg.Add(2) go func() { defer wg.Done() defer b.Close() defer a.Close() _, err := io.Copy(b, a) errChan <- err }() go func() { defer wg.Done() defer a.Close() defer b.Close() _, err := io.Copy(a, b) errChan <- err }() // Wait for both upstream and downstream to close. Since one side // terminating closes the other, the second error in the channel will be // something like EINVAL (though io.Copy() will swallow EOF), so only the // first error is returned. wg.Wait() if len(errChan) > 0 { return <-errChan } return nil } func getVersion() string { return fmt.Sprintf("obfs4proxy-%s", obfs4proxyVersion) } func main() { // Initialize the termination state monitor as soon as possible. termMon = newTermMonitor() // Handle the command line arguments. _, execName := path.Split(os.Args[0]) showVer := flag.Bool("version", false, "Print version and exit") logLevelStr := flag.String("logLevel", "ERROR", "Log level (ERROR/WARN/INFO/DEBUG)") enableLogging := flag.Bool("enableLogging", false, "Log to TOR_PT_STATE_LOCATION/"+obfs4proxyLogFile) unsafeLogging := flag.Bool("unsafeLogging", false, "Disable the address scrubber") flag.Parse() if *showVer { fmt.Printf("%s\n", getVersion()) os.Exit(0) } if err := log.SetLogLevel(*logLevelStr); err != nil { golog.Fatalf("[ERROR]: %s - failed to set log level: %s", execName, err) } // Determine if this is a client or server, initialize the common state. var ptListeners []net.Listener launched := false isClient, err := ptIsClient() if err != nil { golog.Fatalf("[ERROR]: %s - must be run as a managed transport", execName) } if stateDir, err = pt.MakeStateDir(); err != nil { golog.Fatalf("[ERROR]: %s - No state directory: %s", execName, err) } if err = log.Init(*enableLogging, path.Join(stateDir, obfs4proxyLogFile), *unsafeLogging); err != nil { golog.Fatalf("[ERROR]: %s - failed to initialize logging", execName) } if err = transports.Init(); err != nil { log.Errorf("%s - failed to initialize transports: %s", execName, err) os.Exit(-1) } log.Noticef("%s - launched", getVersion()) // Do the managed pluggable transport protocol configuration. if isClient { log.Infof("%s - initializing client transport listeners", execName) launched, ptListeners = clientSetup() } else { log.Infof("%s - initializing server transport listeners", execName) launched, ptListeners = serverSetup() } if !launched { // Initialization failed, the client or server setup routines should // have logged, so just exit here. os.Exit(-1) } log.Infof("%s - accepting connections", execName) defer func() { log.Noticef("%s - terminated", execName) }() // At this point, the pt config protocol is finished, and incoming // connections will be processed. Wait till the parent dies // (immediate exit), a SIGTERM is received (immediate exit), // or a SIGINT is received. if sig := termMon.wait(false); sig == syscall.SIGTERM { return } // Ok, it was the first SIGINT, close all listeners, and wait till, // the parent dies, all the current connections are closed, or either // a SIGINT/SIGTERM is received, and exit. for _, ln := range ptListeners { ln.Close() } termMon.wait(true) }