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383 lines
10 KiB
Go
383 lines
10 KiB
Go
/*
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* Copyright (c) 2014-2015, Yawning Angel <yawning at schwanenlied dot me>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* * Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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// Go language Tor Pluggable Transport suite. Works only as a managed
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// client/server.
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package main
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import (
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"flag"
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"fmt"
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"io"
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golog "log"
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"net"
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"net/url"
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"os"
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"path"
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"sync"
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"syscall"
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"gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/goptlib"
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"golang.org/x/net/proxy"
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"gitlab.com/yawning/obfs4.git/common/log"
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"gitlab.com/yawning/obfs4.git/common/socks5"
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"gitlab.com/yawning/obfs4.git/transports"
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"gitlab.com/yawning/obfs4.git/transports/base"
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)
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const (
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obfs4proxyVersion = "0.0.15-dev"
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obfs4proxyLogFile = "obfs4proxy.log"
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socksAddr = "127.0.0.1:0"
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)
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var (
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stateDir string
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termMon *termMonitor
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)
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func clientSetup() (bool, []net.Listener) {
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ptClientInfo, err := pt.ClientSetup(transports.Transports())
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if err != nil {
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golog.Fatal(err)
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}
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ptClientProxy, err := ptGetProxy(&ptClientInfo)
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if err != nil {
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golog.Fatal(err)
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} else if ptClientProxy != nil {
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pt.ProxyDone()
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}
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// Launch each of the client listeners.
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var launched bool
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listeners := make([]net.Listener, 0, len(ptClientInfo.MethodNames))
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for _, name := range ptClientInfo.MethodNames {
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t := transports.Get(name)
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if t == nil {
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_ = pt.CmethodError(name, "no such transport is supported")
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continue
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}
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f, err := t.ClientFactory(stateDir)
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if err != nil {
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_ = pt.CmethodError(name, "failed to get ClientFactory")
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continue
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}
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ln, err := net.Listen("tcp", socksAddr)
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if err != nil {
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_ = pt.CmethodError(name, err.Error())
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continue
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}
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go func() {
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_ = clientAcceptLoop(f, ln, ptClientProxy)
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}()
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pt.Cmethod(name, socks5.Version(), ln.Addr())
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log.Infof("%s - registered listener: %s", name, ln.Addr())
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listeners = append(listeners, ln)
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launched = true
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}
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pt.CmethodsDone()
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return launched, listeners
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}
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func clientAcceptLoop(f base.ClientFactory, ln net.Listener, proxyURI *url.URL) error {
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defer ln.Close()
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for {
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conn, err := ln.Accept()
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if err != nil {
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return err
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}
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go clientHandler(f, conn, proxyURI)
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}
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}
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func clientHandler(f base.ClientFactory, conn net.Conn, proxyURI *url.URL) {
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defer conn.Close()
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termMon.onHandlerStart()
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defer termMon.onHandlerFinish()
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name := f.Transport().Name()
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// Read the client's SOCKS handshake.
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socksReq, err := socks5.Handshake(conn)
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if err != nil {
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log.Errorf("%s - client failed socks handshake: %s", name, err)
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return
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}
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addrStr := log.ElideAddr(socksReq.Target)
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// Deal with arguments.
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args, err := f.ParseArgs(&socksReq.Args)
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if err != nil {
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log.Errorf("%s(%s) - invalid arguments: %s", name, addrStr, err)
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_ = socksReq.Reply(socks5.ReplyGeneralFailure)
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return
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}
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// Obtain the proxy dialer if any, and create the outgoing TCP connection.
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dialFn := proxy.Direct.Dial
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if proxyURI != nil {
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dialer, err := proxy.FromURL(proxyURI, proxy.Direct)
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if err != nil {
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// This should basically never happen, since config protocol
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// verifies this.
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log.Errorf("%s(%s) - failed to obtain proxy dialer: %s", name, addrStr, log.ElideError(err))
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_ = socksReq.Reply(socks5.ReplyGeneralFailure)
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return
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}
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dialFn = dialer.Dial
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}
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remote, err := f.Dial("tcp", socksReq.Target, dialFn, args)
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if err != nil {
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log.Errorf("%s(%s) - outgoing connection failed: %s", name, addrStr, log.ElideError(err))
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_ = socksReq.Reply(socks5.ErrorToReplyCode(err))
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return
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}
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defer remote.Close()
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err = socksReq.Reply(socks5.ReplySucceeded)
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if err != nil {
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log.Errorf("%s(%s) - SOCKS reply failed: %s", name, addrStr, log.ElideError(err))
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return
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}
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if err = copyLoop(conn, remote); err != nil {
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log.Warnf("%s(%s) - closed connection: %s", name, addrStr, log.ElideError(err))
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} else {
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log.Infof("%s(%s) - closed connection", name, addrStr)
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}
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}
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func serverSetup() (bool, []net.Listener) {
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ptServerInfo, err := pt.ServerSetup(transports.Transports())
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if err != nil {
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golog.Fatal(err)
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}
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var launched bool
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listeners := make([]net.Listener, 0, len(ptServerInfo.Bindaddrs))
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for _, bindaddr := range ptServerInfo.Bindaddrs {
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name := bindaddr.MethodName
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t := transports.Get(name)
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if t == nil {
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_ = pt.SmethodError(name, "no such transport is supported")
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continue
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}
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f, err := t.ServerFactory(stateDir, &bindaddr.Options)
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if err != nil {
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_ = pt.SmethodError(name, err.Error())
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continue
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}
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ln, err := net.ListenTCP("tcp", bindaddr.Addr)
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if err != nil {
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_ = pt.SmethodError(name, err.Error())
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continue
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}
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go func() {
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_ = serverAcceptLoop(f, ln, &ptServerInfo)
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}()
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if args := f.Args(); args != nil {
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pt.SmethodArgs(name, ln.Addr(), *args)
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} else {
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pt.SmethodArgs(name, ln.Addr(), nil)
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}
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log.Infof("%s - registered listener: %s", name, log.ElideAddr(ln.Addr().String()))
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listeners = append(listeners, ln)
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launched = true
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}
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pt.SmethodsDone()
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return launched, listeners
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}
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func serverAcceptLoop(f base.ServerFactory, ln net.Listener, info *pt.ServerInfo) error {
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defer ln.Close()
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for {
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conn, err := ln.Accept()
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if err != nil {
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return err
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}
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go serverHandler(f, conn, info)
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}
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}
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func serverHandler(f base.ServerFactory, conn net.Conn, info *pt.ServerInfo) {
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defer conn.Close()
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termMon.onHandlerStart()
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defer termMon.onHandlerFinish()
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name := f.Transport().Name()
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addrStr := log.ElideAddr(conn.RemoteAddr().String())
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log.Infof("%s(%s) - new connection", name, addrStr)
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// Instantiate the server transport method and handshake.
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remote, err := f.WrapConn(conn)
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if err != nil {
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log.Warnf("%s(%s) - handshake failed: %s", name, addrStr, log.ElideError(err))
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return
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}
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// Connect to the orport.
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orConn, err := pt.DialOr(info, conn.RemoteAddr().String(), name)
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if err != nil {
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log.Errorf("%s(%s) - failed to connect to ORPort: %s", name, addrStr, log.ElideError(err))
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return
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}
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defer orConn.Close()
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if err = copyLoop(orConn, remote); err != nil {
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log.Warnf("%s(%s) - closed connection: %s", name, addrStr, log.ElideError(err))
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} else {
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log.Infof("%s(%s) - closed connection", name, addrStr)
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}
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}
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func copyLoop(a net.Conn, b net.Conn) error {
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// Note: b is always the pt connection. a is the SOCKS/ORPort connection.
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errChan := make(chan error, 2)
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var wg sync.WaitGroup
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wg.Add(2)
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go func() {
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defer wg.Done()
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defer b.Close()
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defer a.Close()
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_, err := io.Copy(b, a)
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errChan <- err
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}()
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go func() {
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defer wg.Done()
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defer a.Close()
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defer b.Close()
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_, err := io.Copy(a, b)
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errChan <- err
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}()
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// Wait for both upstream and downstream to close. Since one side
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// terminating closes the other, the second error in the channel will be
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// something like EINVAL (though io.Copy() will swallow EOF), so only the
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// first error is returned.
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wg.Wait()
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if len(errChan) > 0 {
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return <-errChan
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}
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return nil
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}
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func getVersion() string {
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return fmt.Sprintf("obfs4proxy-%s", obfs4proxyVersion)
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}
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func main() {
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// Initialize the termination state monitor as soon as possible.
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termMon = newTermMonitor()
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// Handle the command line arguments.
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_, execName := path.Split(os.Args[0])
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showVer := flag.Bool("version", false, "Print version and exit")
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logLevelStr := flag.String("logLevel", "ERROR", "Log level (ERROR/WARN/INFO/DEBUG)")
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enableLogging := flag.Bool("enableLogging", false, "Log to TOR_PT_STATE_LOCATION/"+obfs4proxyLogFile)
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unsafeLogging := flag.Bool("unsafeLogging", false, "Disable the address scrubber")
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flag.Parse()
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if *showVer {
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fmt.Printf("%s\n", getVersion()) //nolint:forbidigo
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os.Exit(0)
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}
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if err := log.SetLogLevel(*logLevelStr); err != nil {
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golog.Fatalf("[ERROR]: %s - failed to set log level: %s", execName, err)
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}
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// Determine if this is a client or server, initialize the common state.
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var ptListeners []net.Listener
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var launched bool
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isClient, err := ptIsClient()
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if err != nil {
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golog.Fatalf("[ERROR]: %s - must be run as a managed transport", execName)
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}
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if stateDir, err = pt.MakeStateDir(); err != nil {
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golog.Fatalf("[ERROR]: %s - No state directory: %s", execName, err)
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}
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if err = log.Init(*enableLogging, path.Join(stateDir, obfs4proxyLogFile), *unsafeLogging); err != nil {
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golog.Fatalf("[ERROR]: %s - failed to initialize logging", execName)
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}
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if err = transports.Init(); err != nil {
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log.Errorf("%s - failed to initialize transports: %s", execName, err)
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os.Exit(-1)
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}
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log.Noticef("%s - launched", getVersion())
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// Do the managed pluggable transport protocol configuration.
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if isClient {
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log.Infof("%s - initializing client transport listeners", execName)
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launched, ptListeners = clientSetup()
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} else {
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log.Infof("%s - initializing server transport listeners", execName)
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launched, ptListeners = serverSetup()
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}
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if !launched {
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// Initialization failed, the client or server setup routines should
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// have logged, so just exit here.
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os.Exit(-1)
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}
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log.Infof("%s - accepting connections", execName)
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defer func() {
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log.Noticef("%s - terminated", execName)
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}()
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// At this point, the pt config protocol is finished, and incoming
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// connections will be processed. Wait till the parent dies
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// (immediate exit), a SIGTERM is received (immediate exit),
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// or a SIGINT is received.
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if sig := termMon.wait(false); sig == syscall.SIGTERM {
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return
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}
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// Ok, it was the first SIGINT, close all listeners, and wait till,
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// the parent dies, all the current connections are closed, or either
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// a SIGINT/SIGTERM is received, and exit.
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for _, ln := range ptListeners {
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ln.Close()
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}
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termMon.wait(true)
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}
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