148 lines
3.4 KiB
Go
148 lines
3.4 KiB
Go
// Copyright (C) 2015 The Syncthing Authors.
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//
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// This Source Code Form is subject to the terms of the Mozilla Public
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// License, v. 2.0. If a copy of the MPL was not distributed with this file,
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// You can obtain one at http://mozilla.org/MPL/2.0/.
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package dialer
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import (
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"net"
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"net/http"
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"net/url"
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"os"
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"strings"
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"time"
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"golang.org/x/net/proxy"
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"github.com/syncthing/syncthing/lib/logger"
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)
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var (
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l = logger.DefaultLogger.NewFacility("dialer", "Dialing connections")
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proxyDialer = getDialer(proxy.Direct)
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usingProxy = proxyDialer != proxy.Direct
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noFallback = os.Getenv("ALL_PROXY_NO_FALLBACK") != ""
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)
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type dialFunc func(network, addr string) (net.Conn, error)
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func init() {
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l.SetDebug("dialer", strings.Contains(os.Getenv("STTRACE"), "dialer") || os.Getenv("STTRACE") == "all")
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if usingProxy {
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http.DefaultTransport = &http.Transport{
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Dial: Dial,
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Proxy: http.ProxyFromEnvironment,
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TLSHandshakeTimeout: 10 * time.Second,
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}
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// Defer this, so that logging gets setup.
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go func() {
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time.Sleep(500 * time.Millisecond)
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l.Infoln("Proxy settings detected")
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if noFallback {
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l.Infoln("Proxy fallback disabled")
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}
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}()
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} else {
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go func() {
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time.Sleep(500 * time.Millisecond)
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l.Debugln("Dialer logging disabled, as no proxy was detected")
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}()
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}
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}
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func dialWithFallback(proxyDialFunc dialFunc, fallbackDialFunc dialFunc, network, addr string) (net.Conn, error) {
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conn, err := proxyDialFunc(network, addr)
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if err == nil {
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l.Debugf("Dialing %s address %s via proxy - success, %s -> %s", network, addr, conn.LocalAddr(), conn.RemoteAddr())
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if tcpconn, ok := conn.(*net.TCPConn); ok {
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SetTCPOptions(tcpconn)
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}
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return dialerConn{
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conn, newDialerAddr(network, addr),
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}, nil
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}
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l.Debugf("Dialing %s address %s via proxy - error %s", network, addr, err)
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if noFallback {
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return conn, err
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}
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conn, err = fallbackDialFunc(network, addr)
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if err == nil {
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l.Debugf("Dialing %s address %s via fallback - success, %s -> %s", network, addr, conn.LocalAddr(), conn.RemoteAddr())
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if tcpconn, ok := conn.(*net.TCPConn); ok {
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SetTCPOptions(tcpconn)
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}
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} else {
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l.Debugf("Dialing %s address %s via fallback - error %s", network, addr, err)
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}
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return conn, err
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}
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// This is a rip off of proxy.FromEnvironment with a custom forward dialer
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func getDialer(forward proxy.Dialer) proxy.Dialer {
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allProxy := os.Getenv("all_proxy")
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if len(allProxy) == 0 {
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return forward
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}
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proxyURL, err := url.Parse(allProxy)
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if err != nil {
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return forward
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}
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prxy, err := proxy.FromURL(proxyURL, forward)
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if err != nil {
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return forward
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}
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noProxy := os.Getenv("no_proxy")
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if len(noProxy) == 0 {
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return prxy
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}
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perHost := proxy.NewPerHost(prxy, forward)
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perHost.AddFromString(noProxy)
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return perHost
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}
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type timeoutDirectDialer struct {
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timeout time.Duration
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}
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func (d *timeoutDirectDialer) Dial(network, addr string) (net.Conn, error) {
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return net.DialTimeout(network, addr, d.timeout)
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}
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type dialerConn struct {
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net.Conn
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addr net.Addr
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}
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func (c dialerConn) RemoteAddr() net.Addr {
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return c.addr
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}
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func newDialerAddr(network, addr string) net.Addr {
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netaddr, err := net.ResolveIPAddr(network, addr)
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if err == nil {
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return netaddr
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}
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return fallbackAddr{network, addr}
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}
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type fallbackAddr struct {
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network string
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addr string
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}
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func (a fallbackAddr) Network() string {
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return a.network
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}
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func (a fallbackAddr) String() string {
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return a.addr
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}
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