syncthing/lib/dialer/dialer.go
2015-10-16 19:18:22 +01:00

103 lines
2.5 KiB
Go

// Copyright (C) 2015 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at http://mozilla.org/MPL/2.0/.
package dialer
import (
"net"
"net/http"
"os"
"strings"
"time"
"golang.org/x/net/proxy"
"github.com/syncthing/syncthing/lib/logger"
"github.com/syncthing/syncthing/lib/osutil"
)
var (
l = logger.DefaultLogger.NewFacility("dialer", "Dialing connections")
dialer = proxy.FromEnvironment()
usingProxy = dialer != proxy.Direct
)
func init() {
l.SetDebug("dialer", strings.Contains(os.Getenv("STTRACE"), "dialer") || os.Getenv("STTRACE") == "all")
if usingProxy {
http.DefaultTransport = &http.Transport{
Dial: Dial,
Proxy: http.ProxyFromEnvironment,
TLSHandshakeTimeout: 10 * time.Second,
}
// Defer this, so that logging gets setup.
go func() {
time.Sleep(500 * time.Millisecond)
l.Infoln("Proxy settings detected")
}()
}
}
// Dial tries dialing via proxy if a proxy is configured, and falls back to
// a direct connection if no proxy is defined, or connecting via proxy fails.
func Dial(network, addr string) (net.Conn, error) {
if usingProxy {
conn, err := dialer.Dial(network, addr)
if err == nil {
l.Debugf("Dialing %s address %s via proxy - success, %s -> %s", network, addr, conn.LocalAddr(), conn.RemoteAddr())
if tcpconn, ok := conn.(*net.TCPConn); ok {
osutil.SetTCPOptions(tcpconn)
}
return dialerConn{
conn, newDialerAddr(network, addr),
}, nil
}
l.Debugf("Dialing %s address %s via proxy - error %s", network, addr, err)
}
conn, err := proxy.Direct.Dial(network, addr)
if err == nil {
l.Debugf("Dialing %s address %s directly - success, %s -> %s", network, addr, conn.LocalAddr(), conn.RemoteAddr())
if tcpconn, ok := conn.(*net.TCPConn); ok {
osutil.SetTCPOptions(tcpconn)
}
} else {
l.Debugf("Dialing %s address %s directly - error %s", network, addr, err)
}
return conn, err
}
type dialerConn struct {
net.Conn
addr net.Addr
}
func (c dialerConn) RemoteAddr() net.Addr {
return c.addr
}
func newDialerAddr(network, addr string) net.Addr {
netaddr, err := net.ResolveIPAddr(network, addr)
if err == nil {
return netaddr
}
return fallbackAddr{network, addr}
}
type fallbackAddr struct {
network string
addr string
}
func (a fallbackAddr) Network() string {
return a.network
}
func (a fallbackAddr) String() string {
return a.addr
}