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lib/connections: Refactor

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1. Removes separate relay lists and relay clients/services, just makes it a listen address
2. Easier plugging-in of other transports
3. Allows "hot" disabling and enabling NAT services
4. Allows "hot" listen address changes
5. Changes listen address list with a preferable "default" value just like for discovery
6. Debounces global discovery announcements as external addresses change (which it might alot upon starting)
7. Stops this whole "pick other peers relay by latency". This information is no longer available,
   but I don't think it matters as most of the time other peer only has one relay.
8. Rename ListenAddress to ListenAddresses, as well as in javascript land.
9. Stop serializing deprecated values to JSON

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/2982
This commit is contained in:
Audrius Butkevicius
2016-05-04 19:38:12 +00:00
committed by Jakob Borg
parent 09832abe50
commit 674fc566bb
45 changed files with 1683 additions and 1707 deletions
Download Patch File Download Diff File Expand all files Collapse all files

638
lib/connections/connections.go
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@@ -1,638 +0,0 @@
// 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 connections
import (
"crypto/tls"
"encoding/binary"
"fmt"
"io"
"net"
"net/url"
"sync"
"time"
"github.com/juju/ratelimit"
"github.com/syncthing/syncthing/lib/config"
"github.com/syncthing/syncthing/lib/discover"
"github.com/syncthing/syncthing/lib/events"
"github.com/syncthing/syncthing/lib/model"
"github.com/syncthing/syncthing/lib/nat"
"github.com/syncthing/syncthing/lib/protocol"
"github.com/syncthing/syncthing/lib/relay"
"github.com/syncthing/syncthing/lib/relay/client"
"github.com/syncthing/syncthing/lib/util"
"github.com/thejerf/suture"
)
type DialerFactory func(*url.URL, *tls.Config) (*tls.Conn, error)
type ListenerFactory func(*url.URL, *tls.Config, chan<- model.IntermediateConnection)
var (
dialers = make(map[string]DialerFactory, 0)
listeners = make(map[string]ListenerFactory, 0)
)
type Model interface {
protocol.Model
AddConnection(conn model.Connection, hello protocol.HelloMessage)
ConnectedTo(remoteID protocol.DeviceID) bool
IsPaused(remoteID protocol.DeviceID) bool
OnHello(protocol.DeviceID, net.Addr, protocol.HelloMessage)
GetHello(protocol.DeviceID) protocol.HelloMessage
}
// Service listens on TLS and dials configured unconnected devices. Successful
// connections are handed to the model.
type Service struct {
*suture.Supervisor
cfg *config.Wrapper
myID protocol.DeviceID
model Model
tlsCfg *tls.Config
discoverer discover.Finder
conns chan model.IntermediateConnection
mappings []*nat.Mapping
relayService relay.Service
bepProtocolName string
tlsDefaultCommonName string
lans []*net.IPNet
writeRateLimit *ratelimit.Bucket
readRateLimit *ratelimit.Bucket
mut sync.RWMutex
connType map[protocol.DeviceID]model.ConnectionType
}
func NewConnectionService(cfg *config.Wrapper, myID protocol.DeviceID, mdl Model, tlsCfg *tls.Config, discoverer discover.Finder, mappings []*nat.Mapping,
relayService relay.Service, bepProtocolName string, tlsDefaultCommonName string, lans []*net.IPNet) *Service {
service := &Service{
Supervisor: suture.NewSimple("connections.Service"),
cfg: cfg,
myID: myID,
model: mdl,
tlsCfg: tlsCfg,
discoverer: discoverer,
mappings: mappings,
relayService: relayService,
conns: make(chan model.IntermediateConnection),
bepProtocolName: bepProtocolName,
tlsDefaultCommonName: tlsDefaultCommonName,
lans: lans,
connType: make(map[protocol.DeviceID]model.ConnectionType),
}
cfg.Subscribe(service)
// The rate variables are in KiB/s in the UI (despite the camel casing
// of the name). We multiply by 1024 here to get B/s.
if service.cfg.Options().MaxSendKbps > 0 {
service.writeRateLimit = ratelimit.NewBucketWithRate(float64(1024*service.cfg.Options().MaxSendKbps), int64(5*1024*service.cfg.Options().MaxSendKbps))
}
if service.cfg.Options().MaxRecvKbps > 0 {
service.readRateLimit = ratelimit.NewBucketWithRate(float64(1024*service.cfg.Options().MaxRecvKbps), int64(5*1024*service.cfg.Options().MaxRecvKbps))
}
// There are several moving parts here; one routine per listening address
// to handle incoming connections, one routine to periodically attempt
// outgoing connections, one routine to the the common handling
// regardless of whether the connection was incoming or outgoing.
// Furthermore, a relay service which handles incoming requests to connect
// via the relays.
//
// TODO: Clean shutdown, and/or handling config changes on the fly. We
// partly do this now - new devices and addresses will be picked up, but
// not new listen addresses and we don't support disconnecting devices
// that are removed and so on...
service.Add(serviceFunc(service.connect))
for _, addr := range service.cfg.Options().ListenAddress {
uri, err := url.Parse(addr)
if err != nil {
l.Infoln("Failed to parse listen address:", addr, err)
continue
}
listener, ok := listeners[uri.Scheme]
if !ok {
l.Infoln("Unknown listen address scheme:", uri.String())
continue
}
l.Debugln("listening on", uri)
service.Add(serviceFunc(func() {
listener(uri, service.tlsCfg, service.conns)
}))
}
service.Add(serviceFunc(service.handle))
if service.relayService != nil {
service.Add(serviceFunc(service.acceptRelayConns))
}
for _, mapping := range mappings {
mapping.OnChanged(func(m *nat.Mapping, added, removed []nat.Address) {
events.Default.Log(events.ExternalPortMappingChanged, map[string]interface{}{
"protocol": m.Protocol(),
"local": m.Address().String(),
"added": added,
"removed": removed,
})
})
}
return service
}
func (s *Service) handle() {
next:
for c := range s.conns {
cs := c.ConnectionState()
// We should have negotiated the next level protocol "bep/1.0" as part
// of the TLS handshake. Unfortunately this can't be a hard error,
// because there are implementations out there that don't support
// protocol negotiation (iOS for one...).
if !cs.NegotiatedProtocolIsMutual || cs.NegotiatedProtocol != s.bepProtocolName {
l.Infof("Peer %s did not negotiate bep/1.0", c.RemoteAddr())
}
// We should have received exactly one certificate from the other
// side. If we didn't, they don't have a device ID and we drop the
// connection.
certs := cs.PeerCertificates
if cl := len(certs); cl != 1 {
l.Infof("Got peer certificate list of length %d != 1 from %s; protocol error", cl, c.RemoteAddr())
c.Close()
continue
}
remoteCert := certs[0]
remoteID := protocol.NewDeviceID(remoteCert.Raw)
// The device ID should not be that of ourselves. It can happen
// though, especially in the presence of NAT hairpinning, multiple
// clients between the same NAT gateway, and global discovery.
if remoteID == s.myID {
l.Infof("Connected to myself (%s) - should not happen", remoteID)
c.Close()
continue
}
hello, err := exchangeHello(c, s.model.GetHello(remoteID))
if err != nil {
l.Infof("Failed to exchange Hello messages with %s (%s): %s", remoteID, c.RemoteAddr(), err)
c.Close()
continue next
}
s.model.OnHello(remoteID, c.RemoteAddr(), hello)
// If we have a relay connection, and the new incoming connection is
// not a relay connection, we should drop that, and prefer the this one.
s.mut.RLock()
skip := false
ct, ok := s.connType[remoteID]
if ok && !ct.IsDirect() && c.Type.IsDirect() {
l.Debugln("Switching connections", remoteID)
s.model.Close(remoteID, protocol.ErrSwitchingConnections)
} else if s.model.ConnectedTo(remoteID) {
// We should not already be connected to the other party. TODO: This
// could use some better handling. If the old connection is dead but
// hasn't timed out yet we may want to drop *that* connection and keep
// this one. But in case we are two devices connecting to each other
// in parallel we don't want to do that or we end up with no
// connections still established...
l.Infof("Connected to already connected device (%s)", remoteID)
c.Close()
skip = true
} else if s.model.IsPaused(remoteID) {
l.Infof("Connection from paused device (%s)", remoteID)
c.Close()
skip = true
}
s.mut.RUnlock()
if skip {
continue
}
for deviceID, deviceCfg := range s.cfg.Devices() {
if deviceID == remoteID {
// Verify the name on the certificate. By default we set it to
// "syncthing" when generating, but the user may have replaced
// the certificate and used another name.
certName := deviceCfg.CertName
if certName == "" {
certName = s.tlsDefaultCommonName
}
err := remoteCert.VerifyHostname(certName)
if err != nil {
// Incorrect certificate name is something the user most
// likely wants to know about, since it's an advanced
// config. Warn instead of Info.
l.Warnf("Bad certificate from %s (%v): %v", remoteID, c.RemoteAddr(), err)
c.Close()
continue next
}
// If rate limiting is set, and based on the address we should
// limit the connection, then we wrap it in a limiter.
limit := s.shouldLimit(c.RemoteAddr())
wr := io.Writer(c.Conn)
if limit && s.writeRateLimit != nil {
wr = NewWriteLimiter(c.Conn, s.writeRateLimit)
}
rd := io.Reader(c.Conn)
if limit && s.readRateLimit != nil {
rd = NewReadLimiter(c.Conn, s.readRateLimit)
}
name := fmt.Sprintf("%s-%s (%s)", c.LocalAddr(), c.RemoteAddr(), c.Type)
protoConn := protocol.NewConnection(remoteID, rd, wr, s.model, name, deviceCfg.Compression)
l.Infof("Established secure connection to %s at %s", remoteID, name)
l.Debugf("cipher suite: %04X in lan: %t", c.ConnectionState().CipherSuite, !limit)
s.mut.Lock()
s.model.AddConnection(model.Connection{
Conn: c,
Connection: protoConn,
Type: c.Type,
}, hello)
s.connType[remoteID] = c.Type
s.mut.Unlock()
continue next
}
}
l.Infof("Connection from %s (%s) with ignored device ID %s", c.RemoteAddr(), c.Type, remoteID)
c.Close()
}
}
func (s *Service) connect() {
lastRelayCheck := make(map[protocol.DeviceID]time.Time)
delay := time.Second
for {
l.Debugln("Reconnect loop")
relaysEnabled := s.cfg.Options().RelaysEnabled
nextDevice:
for deviceID, deviceCfg := range s.cfg.Devices() {
if deviceID == s.myID {
continue
}
l.Debugln("Reconnect loop for", deviceID)
s.mut.RLock()
paused := s.model.IsPaused(deviceID)
connected := s.model.ConnectedTo(deviceID)
ct, ok := s.connType[deviceID]
s.mut.RUnlock()
if paused {
continue
}
if connected && ok && ct.IsDirect() {
l.Debugln("Already connected to", deviceID, "via", ct.String())
continue
}
addrs, relays := s.resolveAddresses(deviceID, deviceCfg.Addresses)
for _, addr := range addrs {
if conn := s.connectDirect(deviceID, addr); conn != nil {
l.Debugln("Connecting to", deviceID, "via", addr, "succeeded")
if connected {
s.model.Close(deviceID, protocol.ErrSwitchingConnections)
}
s.conns <- model.IntermediateConnection{
Conn: conn,
Type: model.ConnectionTypeDirectDial,
}
continue nextDevice
}
l.Debugln("Connecting to", deviceID, "via", addr, "failed")
}
// Only connect via relays if not already connected
// Also, do not set lastRelayCheck time if we have no relays,
// as otherwise when we do discover relays, we might have to
// wait up to RelayReconnectIntervalM to connect again.
// Also, do not try relays if we are explicitly told not to.
if connected || len(relays) == 0 || !relaysEnabled {
l.Debugln("Not connecting via relay", connected, len(relays) == 0, !relaysEnabled)
continue nextDevice
}
reconIntv := time.Duration(s.cfg.Options().RelayReconnectIntervalM) * time.Minute
if last, ok := lastRelayCheck[deviceID]; ok && time.Since(last) < reconIntv {
l.Debugln("Skipping connecting via relay to", deviceID, "last checked at", last)
continue nextDevice
}
l.Debugln("Trying relay connections to", deviceID, relays)
lastRelayCheck[deviceID] = time.Now()
for _, addr := range relays {
if conn := s.connectViaRelay(deviceID, addr); conn != nil {
l.Debugln("Connecting to", deviceID, "via", addr, "succeeded")
s.conns <- model.IntermediateConnection{
Conn: conn,
Type: model.ConnectionTypeRelayDial,
}
continue nextDevice
}
l.Debugln("Connecting to", deviceID, "via", addr, "failed")
}
}
time.Sleep(delay)
delay *= 2
if maxD := time.Duration(s.cfg.Options().ReconnectIntervalS) * time.Second; delay > maxD {
delay = maxD
}
}
}
func (s *Service) resolveAddresses(deviceID protocol.DeviceID, inAddrs []string) (addrs []string, relays []discover.Relay) {
for _, addr := range inAddrs {
if addr == "dynamic" {
if s.discoverer != nil {
if t, r, err := s.discoverer.Lookup(deviceID); err == nil {
addrs = append(addrs, t...)
relays = append(relays, r...)
}
}
} else {
addrs = append(addrs, addr)
}
}
return
}
func (s *Service) connectDirect(deviceID protocol.DeviceID, addr string) *tls.Conn {
uri, err := url.Parse(addr)
if err != nil {
l.Infoln("Failed to parse connection url:", addr, err)
return nil
}
dialer, ok := dialers[uri.Scheme]
if !ok {
l.Infoln("Unknown address schema", uri)
return nil
}
l.Debugln("dial", deviceID, uri)
conn, err := dialer(uri, s.tlsCfg)
if err != nil {
l.Debugln("dial failed", deviceID, uri, err)
return nil
}
return conn
}
func (s *Service) connectViaRelay(deviceID protocol.DeviceID, addr discover.Relay) *tls.Conn {
uri, err := url.Parse(addr.URL)
if err != nil {
l.Infoln("Failed to parse relay connection url:", addr, err)
return nil
}
inv, err := client.GetInvitationFromRelay(uri, deviceID, s.tlsCfg.Certificates, 10*time.Second)
if err != nil {
l.Debugf("Failed to get invitation for %s from %s: %v", deviceID, uri, err)
return nil
}
l.Debugln("Succesfully retrieved relay invitation", inv, "from", uri)
conn, err := client.JoinSession(inv)
if err != nil {
l.Debugf("Failed to join relay session %s: %v", inv, err)
return nil
}
l.Debugln("Successfully joined relay session", inv)
var tc *tls.Conn
if inv.ServerSocket {
tc = tls.Server(conn, s.tlsCfg)
} else {
tc = tls.Client(conn, s.tlsCfg)
}
err = tc.Handshake()
if err != nil {
l.Infof("TLS handshake (BEP/relay %s): %v", inv, err)
tc.Close()
return nil
}
return tc
}
func (s *Service) acceptRelayConns() {
for {
conn := s.relayService.Accept()
s.conns <- model.IntermediateConnection{
Conn: conn,
Type: model.ConnectionTypeRelayAccept,
}
}
}
func (s *Service) shouldLimit(addr net.Addr) bool {
if s.cfg.Options().LimitBandwidthInLan {
return true
}
tcpaddr, ok := addr.(*net.TCPAddr)
if !ok {
return true
}
for _, lan := range s.lans {
if lan.Contains(tcpaddr.IP) {
return false
}
}
return !tcpaddr.IP.IsLoopback()
}
func (s *Service) VerifyConfiguration(from, to config.Configuration) error {
return nil
}
func (s *Service) CommitConfiguration(from, to config.Configuration) bool {
// We require a restart if a device as been removed.
newDevices := make(map[protocol.DeviceID]bool, len(to.Devices))
for _, dev := range to.Devices {
newDevices[dev.DeviceID] = true
}
for _, dev := range from.Devices {
if !newDevices[dev.DeviceID] {
return false
}
}
return true
}
// ExternalAddresses returns a list of addresses that are our best guess for
// where we are reachable from the outside. As a special case, we may return
// one or more addresses with an empty IP address (0.0.0.0 or ::) and just
// port number - this means that the outside address of a NAT gateway should
// be substituted.
func (s *Service) ExternalAddresses() []string {
return s.addresses(false)
}
// AllAddresses returns a list of addresses that are our best guess for where
// we are reachable from the local network. Same conditions as
// ExternalAddresses, but private IPv4 addresses are included.
func (s *Service) AllAddresses() []string {
return s.addresses(true)
}
func (s *Service) addresses(includePrivateIPV4 bool) []string {
var addrs []string
// Grab our listen addresses from the config. Unspecified ones are passed
// on verbatim (to be interpreted by a global discovery server or local
// discovery peer). Public addresses are passed on verbatim. Private
// addresses are filtered.
for _, addrStr := range s.cfg.Options().ListenAddress {
addrURL, err := url.Parse(addrStr)
if err != nil {
l.Infoln("Listen address", addrStr, "is invalid:", err)
continue
}
addr, err := net.ResolveTCPAddr(addrURL.Scheme, addrURL.Host)
if err != nil {
l.Infoln("Listen address", addrStr, "is invalid:", err)
continue
}
if addr.IP == nil || addr.IP.IsUnspecified() {
// Address like 0.0.0.0:22000 or [::]:22000 or :22000; include as is.
addrs = append(addrs, util.Address(addrURL.Scheme, addr.String()))
} else if isPublicIPv4(addr.IP) || isPublicIPv6(addr.IP) {
// A public address; include as is.
addrs = append(addrs, util.Address(addrURL.Scheme, addr.String()))
} else if includePrivateIPV4 && addr.IP.To4().IsGlobalUnicast() {
// A private IPv4 address.
addrs = append(addrs, util.Address(addrURL.Scheme, addr.String()))
}
}
// Add addresses provided by the mappings from the NAT service.
for _, mapping := range s.mappings {
for _, addr := range mapping.ExternalAddresses() {
addrs = append(addrs, fmt.Sprintf("tcp://%s", addr))
}
}
return addrs
}
func isPublicIPv4(ip net.IP) bool {
ip = ip.To4()
if ip == nil {
// Not an IPv4 address (IPv6)
return false
}
// IsGlobalUnicast below only checks that it's not link local or
// multicast, and we want to exclude private (NAT:ed) addresses as well.
rfc1918 := []net.IPNet{
{IP: net.IP{10, 0, 0, 0}, Mask: net.IPMask{255, 0, 0, 0}},
{IP: net.IP{172, 16, 0, 0}, Mask: net.IPMask{255, 240, 0, 0}},
{IP: net.IP{192, 168, 0, 0}, Mask: net.IPMask{255, 255, 0, 0}},
}
for _, n := range rfc1918 {
if n.Contains(ip) {
return false
}
}
return ip.IsGlobalUnicast()
}
func isPublicIPv6(ip net.IP) bool {
if ip.To4() != nil {
// Not an IPv6 address (IPv4)
// (To16() returns a v6 mapped v4 address so can't be used to check
// that it's an actual v6 address)
return false
}
return ip.IsGlobalUnicast()
}
func exchangeHello(c net.Conn, h protocol.HelloMessage) (protocol.HelloMessage, error) {
if err := c.SetDeadline(time.Now().Add(2 * time.Second)); err != nil {
return protocol.HelloMessage{}, err
}
defer c.SetDeadline(time.Time{})
header := make([]byte, 8)
msg := h.MustMarshalXDR()
binary.BigEndian.PutUint32(header[:4], protocol.HelloMessageMagic)
binary.BigEndian.PutUint32(header[4:], uint32(len(msg)))
if _, err := c.Write(header); err != nil {
return protocol.HelloMessage{}, err
}
if _, err := c.Write(msg); err != nil {
return protocol.HelloMessage{}, err
}
if _, err := io.ReadFull(c, header); err != nil {
return protocol.HelloMessage{}, err
}
if binary.BigEndian.Uint32(header[:4]) != protocol.HelloMessageMagic {
return protocol.HelloMessage{}, fmt.Errorf("incorrect magic")
}
msgSize := binary.BigEndian.Uint32(header[4:])
if msgSize > 1024 {
return protocol.HelloMessage{}, fmt.Errorf("hello message too big")
}
buf := make([]byte, msgSize)
var hello protocol.HelloMessage
if _, err := io.ReadFull(c, buf); err != nil {
return protocol.HelloMessage{}, err
}
if err := hello.UnmarshalXDR(buf); err != nil {
return protocol.HelloMessage{}, err
}
return hello, nil
}
// serviceFunc wraps a function to create a suture.Service without stop
// functionality.
type serviceFunc func()
func (f serviceFunc) Serve() { f() }
func (f serviceFunc) Stop() {}

99
lib/connections/connections_tcp.go
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@@ -1,99 +0,0 @@
// 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 connections
import (
"crypto/tls"
"net"
"net/url"
"strings"
"github.com/syncthing/syncthing/lib/dialer"
"github.com/syncthing/syncthing/lib/model"
)
func init() {
for _, network := range []string{"tcp", "tcp4", "tcp6"} {
dialers[network] = makeTCPDialer(network)
listeners[network] = makeTCPListener(network)
}
}
func makeTCPDialer(network string) DialerFactory {
return func(uri *url.URL, tlsCfg *tls.Config) (*tls.Conn, error) {
// Check that there is a port number in uri.Host, otherwise add one.
host, port, err := net.SplitHostPort(uri.Host)
if err != nil && strings.HasPrefix(err.Error(), "missing port") {
// addr is on the form "1.2.3.4"
uri.Host = net.JoinHostPort(uri.Host, "22000")
} else if err == nil && port == "" {
// addr is on the form "1.2.3.4:"
uri.Host = net.JoinHostPort(host, "22000")
}
// Don't try to resolve the address before dialing. The dialer may be a
// proxy, and we should let the proxy do the resolving in that case.
conn, err := dialer.Dial(network, uri.Host)
if err != nil {
l.Debugln(err)
return nil, err
}
tc := tls.Client(conn, tlsCfg)
err = tc.Handshake()
if err != nil {
tc.Close()
return nil, err
}
return tc, nil
}
}
func makeTCPListener(network string) ListenerFactory {
return func(uri *url.URL, tlsCfg *tls.Config, conns chan<- model.IntermediateConnection) {
tcaddr, err := net.ResolveTCPAddr(network, uri.Host)
if err != nil {
l.Fatalln("listen (BEP/tcp):", err)
return
}
listener, err := net.ListenTCP(network, tcaddr)
if err != nil {
l.Fatalln("listen (BEP/tcp):", err)
return
}
for {
conn, err := listener.Accept()
if err != nil {
l.Warnln("Accepting connection (BEP/tcp):", err)
continue
}
l.Debugln("connect from", conn.RemoteAddr())
err = dialer.SetTCPOptions(conn.(*net.TCPConn))
if err != nil {
l.Infoln(err)
}
tc := tls.Server(conn, tlsCfg)
err = tc.Handshake()
if err != nil {
l.Infoln("TLS handshake (BEP/tcp):", err)
tc.Close()
continue
}
conns <- model.IntermediateConnection{
Conn: tc,
Type: model.ConnectionTypeDirectAccept,
}
}
}
}

82
lib/connections/relay_dial.go Normal file
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@@ -0,0 +1,82 @@
// Copyright (C) 2016 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 connections
import (
"crypto/tls"
"net"
"net/url"
"time"
"github.com/syncthing/syncthing/lib/config"
"github.com/syncthing/syncthing/lib/dialer"
"github.com/syncthing/syncthing/lib/protocol"
"github.com/syncthing/syncthing/lib/relay/client"
)
const relayPriority = 200
func init() {
dialers["relay"] = newRelayDialer
}
type relayDialer struct {
cfg *config.Wrapper
tlsCfg *tls.Config
}
func (d *relayDialer) Dial(id protocol.DeviceID, uri *url.URL) (IntermediateConnection, error) {
inv, err := client.GetInvitationFromRelay(uri, id, d.tlsCfg.Certificates, 10*time.Second)
if err != nil {
return IntermediateConnection{}, err
}
conn, err := client.JoinSession(inv)
if err != nil {
return IntermediateConnection{}, err
}
err = dialer.SetTCPOptions(conn.(*net.TCPConn))
if err != nil {
conn.Close()
return IntermediateConnection{}, err
}
var tc *tls.Conn
if inv.ServerSocket {
tc = tls.Server(conn, d.tlsCfg)
} else {
tc = tls.Client(conn, d.tlsCfg)
}
err = tc.Handshake()
if err != nil {
tc.Close()
return IntermediateConnection{}, err
}
return IntermediateConnection{tc, "Relay (Client)", relayPriority}, nil
}
func (relayDialer) Priority() int {
return relayPriority
}
func (d *relayDialer) RedialFrequency() time.Duration {
return time.Duration(d.cfg.Options().RelayReconnectIntervalM) * time.Minute
}
func (d *relayDialer) String() string {
return "Relay Dialer"
}
func newRelayDialer(cfg *config.Wrapper, tlsCfg *tls.Config) genericDialer {
return &relayDialer{
cfg: cfg,
tlsCfg: tlsCfg,
}
}

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// Copyright (C) 2016 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 connections
import (
"crypto/tls"
"net"
"net/url"
"sync"
"time"
"github.com/syncthing/syncthing/lib/dialer"
"github.com/syncthing/syncthing/lib/nat"
"github.com/syncthing/syncthing/lib/relay/client"
)
func init() {
listeners["relay"] = newRelayListener
listeners["dynamic+http"] = newRelayListener
listeners["dynamic+https"] = newRelayListener
}
type relayListener struct {
onAddressesChangedNotifier
uri *url.URL
tlsCfg *tls.Config
conns chan IntermediateConnection
err error
client client.RelayClient
mut sync.RWMutex
}
func (t *relayListener) Serve() {
t.mut.Lock()
t.err = nil
t.mut.Unlock()
clnt, err := client.NewClient(t.uri, t.tlsCfg.Certificates, nil, 10*time.Second)
if err != nil {
t.mut.Lock()
t.err = err
t.mut.Unlock()
l.Warnln("listen (BEP/relay):", err)
return
}
go clnt.Serve()
t.mut.Lock()
t.client = clnt
t.mut.Unlock()
oldURI := clnt.URI()
for {
select {
case inv, ok := <-t.client.Invitations():
if !ok {
return
}
conn, err := client.JoinSession(inv)
if err != nil {
l.Warnln("Joining relay session (BEP/relay):", err)
continue
}
err = dialer.SetTCPOptions(conn.(*net.TCPConn))
if err != nil {
l.Infoln(err)
}
var tc *tls.Conn
if inv.ServerSocket {
tc = tls.Server(conn, t.tlsCfg)
} else {
tc = tls.Client(conn, t.tlsCfg)
}
err = tc.Handshake()
if err != nil {
tc.Close()
l.Infoln("TLS handshake (BEP/relay):", err)
continue
}
t.conns <- IntermediateConnection{tc, "Relay (Server)", relayPriority}
// Poor mans notifier that informs the connection service that the
// relay URI has changed. This can only happen when we connect to a
// relay via dynamic+http(s) pool, which upon a relay failing/dropping
// us, would pick a different one.
case <-time.After(10 * time.Second):
currentURI := clnt.URI()
if currentURI != oldURI {
oldURI = currentURI
t.notifyAddressesChanged(t)
}
}
}
}
func (t *relayListener) Stop() {
t.mut.RLock()
if t.client != nil {
t.client.Stop()
}
t.mut.RUnlock()
}
func (t *relayListener) URI() *url.URL {
return t.uri
}
func (t *relayListener) WANAddresses() []*url.URL {
t.mut.RLock()
client := t.client
t.mut.RUnlock()
if client == nil {
return nil
}
curi := client.URI()
if curi == nil {
return nil
}
return []*url.URL{curi}
}
func (t *relayListener) LANAddresses() []*url.URL {
return t.WANAddresses()
}
func (t *relayListener) Error() error {
t.mut.RLock()
err := t.err
var cerr error
if t.client != nil {
cerr = t.client.Error()
}
t.mut.RUnlock()
if err != nil {
return err
}
return cerr
}
func (t *relayListener) String() string {
return t.uri.String()
}
func newRelayListener(uri *url.URL, tlsCfg *tls.Config, conns chan IntermediateConnection, natService *nat.Service) genericListener {
return &relayListener{
uri: uri,
tlsCfg: tlsCfg,
conns: conns,
}
}

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lib/connections/service.go Normal file
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// 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 connections
import (
"crypto/tls"
"encoding/binary"
"fmt"
"io"
"net"
"net/url"
"time"
"github.com/juju/ratelimit"
"github.com/syncthing/syncthing/lib/config"
"github.com/syncthing/syncthing/lib/discover"
"github.com/syncthing/syncthing/lib/events"
"github.com/syncthing/syncthing/lib/nat"
"github.com/syncthing/syncthing/lib/protocol"
"github.com/syncthing/syncthing/lib/sync"
"github.com/syncthing/syncthing/lib/util"
// Registers NAT service providers
_ "github.com/syncthing/syncthing/lib/pmp"
_ "github.com/syncthing/syncthing/lib/upnp"
"github.com/thejerf/suture"
)
var (
dialers = make(map[string]dialerFactory, 0)
listeners = make(map[string]listenerFactory, 0)
)
// Service listens and dials all configured unconnected devices, via supported
// dialers. Successful connections are handed to the model.
type Service struct {
*suture.Supervisor
cfg *config.Wrapper
myID protocol.DeviceID
model Model
tlsCfg *tls.Config
discoverer discover.Finder
conns chan IntermediateConnection
bepProtocolName string
tlsDefaultCommonName string
lans []*net.IPNet
writeRateLimit *ratelimit.Bucket
readRateLimit *ratelimit.Bucket
natService *nat.Service
natServiceToken *suture.ServiceToken
mut sync.RWMutex
listeners map[string]genericListener
listenerTokens map[string]suture.ServiceToken
currentConnection map[protocol.DeviceID]Connection
}
func NewService(cfg *config.Wrapper, myID protocol.DeviceID, mdl Model, tlsCfg *tls.Config, discoverer discover.Finder,
bepProtocolName string, tlsDefaultCommonName string, lans []*net.IPNet) *Service {
service := &Service{
Supervisor: suture.NewSimple("connections.Service"),
cfg: cfg,
myID: myID,
model: mdl,
tlsCfg: tlsCfg,
discoverer: discoverer,
conns: make(chan IntermediateConnection),
bepProtocolName: bepProtocolName,
tlsDefaultCommonName: tlsDefaultCommonName,
lans: lans,
natService: nat.NewService(myID, cfg),
mut: sync.NewRWMutex(),
listeners: make(map[string]genericListener),
listenerTokens: make(map[string]suture.ServiceToken),
currentConnection: make(map[protocol.DeviceID]Connection),
}
cfg.Subscribe(service)
// The rate variables are in KiB/s in the UI (despite the camel casing
// of the name). We multiply by 1024 here to get B/s.
if service.cfg.Options().MaxSendKbps > 0 {
service.writeRateLimit = ratelimit.NewBucketWithRate(float64(1024*service.cfg.Options().MaxSendKbps), int64(5*1024*service.cfg.Options().MaxSendKbps))
}
if service.cfg.Options().MaxRecvKbps > 0 {
service.readRateLimit = ratelimit.NewBucketWithRate(float64(1024*service.cfg.Options().MaxRecvKbps), int64(5*1024*service.cfg.Options().MaxRecvKbps))
}
// There are several moving parts here; one routine per listening address
// (handled in configuration changing) to handle incoming connections,
// one routine to periodically attempt outgoing connections, one routine to
// the the common handling regardless of whether the connection was
// incoming or outgoing.
service.Add(serviceFunc(service.connect))
service.Add(serviceFunc(service.handle))
raw := cfg.Raw()
// Actually starts the listeners and NAT service
service.CommitConfiguration(raw, raw)
return service
}
func (s *Service) handle() {
next:
for c := range s.conns {
cs := c.ConnectionState()
// We should have negotiated the next level protocol "bep/1.0" as part
// of the TLS handshake. Unfortunately this can't be a hard error,
// because there are implementations out there that don't support
// protocol negotiation (iOS for one...).
if !cs.NegotiatedProtocolIsMutual || cs.NegotiatedProtocol != s.bepProtocolName {
l.Infof("Peer %s did not negotiate bep/1.0", c.RemoteAddr())
}
// We should have received exactly one certificate from the other
// side. If we didn't, they don't have a device ID and we drop the
// connection.
certs := cs.PeerCertificates
if cl := len(certs); cl != 1 {
l.Infof("Got peer certificate list of length %d != 1 from %s; protocol error", cl, c.RemoteAddr())
c.Close()
continue
}
remoteCert := certs[0]
remoteID := protocol.NewDeviceID(remoteCert.Raw)
// The device ID should not be that of ourselves. It can happen
// though, especially in the presence of NAT hairpinning, multiple
// clients between the same NAT gateway, and global discovery.
if remoteID == s.myID {
l.Infof("Connected to myself (%s) - should not happen", remoteID)
c.Close()
continue
}
hello, err := exchangeHello(c, s.model.GetHello(remoteID))
if err != nil {
l.Infof("Failed to exchange Hello messages with %s (%s): %s", remoteID, c.RemoteAddr(), err)
c.Close()
continue
}
s.model.OnHello(remoteID, c.RemoteAddr(), hello)
// If we have a relay connection, and the new incoming connection is
// not a relay connection, we should drop that, and prefer the this one.
s.mut.RLock()
skip := false
ct, ok := s.currentConnection[remoteID]
// Lower priority is better, just like nice etc.
if ok && ct.Priority > c.Priority {
l.Debugln("Switching connections", remoteID)
s.model.Close(remoteID, protocol.ErrSwitchingConnections)
} else if s.model.ConnectedTo(remoteID) {
// We should not already be connected to the other party. TODO: This
// could use some better handling. If the old connection is dead but
// hasn't timed out yet we may want to drop *that* connection and keep
// this one. But in case we are two devices connecting to each other
// in parallel we don't want to do that or we end up with no
// connections still established...
l.Infof("Connected to already connected device (%s)", remoteID)
c.Close()
skip = true
} else if s.model.IsPaused(remoteID) {
l.Infof("Connection from paused device (%s)", remoteID)
c.Close()
skip = true
}
s.mut.RUnlock()
if skip {
continue
}
for deviceID, deviceCfg := range s.cfg.Devices() {
if deviceID == remoteID {
// Verify the name on the certificate. By default we set it to
// "syncthing" when generating, but the user may have replaced
// the certificate and used another name.
certName := deviceCfg.CertName
if certName == "" {
certName = s.tlsDefaultCommonName
}
err := remoteCert.VerifyHostname(certName)
if err != nil {
// Incorrect certificate name is something the user most
// likely wants to know about, since it's an advanced
// config. Warn instead of Info.
l.Warnf("Bad certificate from %s (%v): %v", remoteID, c.RemoteAddr(), err)
c.Close()
continue next
}
// If rate limiting is set, and based on the address we should
// limit the connection, then we wrap it in a limiter.
limit := s.shouldLimit(c.RemoteAddr())
wr := io.Writer(c)
if limit && s.writeRateLimit != nil {
wr = NewWriteLimiter(c, s.writeRateLimit)
}
rd := io.Reader(c)
if limit && s.readRateLimit != nil {
rd = NewReadLimiter(c, s.readRateLimit)
}
name := fmt.Sprintf("%s-%s (%s)", c.LocalAddr(), c.RemoteAddr(), c.Type)
protoConn := protocol.NewConnection(remoteID, rd, wr, s.model, name, deviceCfg.Compression)
modelConn := Connection{c, protoConn}
l.Infof("Established secure connection to %s at %s", remoteID, name)
l.Debugf("cipher suite: %04X in lan: %t", c.ConnectionState().CipherSuite, !limit)
s.mut.Lock()
s.model.AddConnection(modelConn, hello)
s.currentConnection[remoteID] = modelConn
s.mut.Unlock()
continue next
}
}
l.Infof("Connection from %s (%s) with ignored device ID %s", c.RemoteAddr(), c.Type, remoteID)
c.Close()
}
}
func (s *Service) connect() {
nextDial := make(map[string]time.Time)
delay := time.Second
sleep := time.Second
for {
l.Debugln("Reconnect loop")
now := time.Now()
var seen []string
nextDevice:
for deviceID, deviceCfg := range s.cfg.Devices() {
if deviceID == s.myID {
continue
}
l.Debugln("Reconnect loop for", deviceID)
s.mut.RLock()
paused := s.model.IsPaused(deviceID)
connected := s.model.ConnectedTo(deviceID)
ct := s.currentConnection[deviceID]
s.mut.RUnlock()
if paused {
continue
}
var addrs []string
for _, addr := range deviceCfg.Addresses {
if addr == "dynamic" {
if s.discoverer != nil {
if t, err := s.discoverer.Lookup(deviceID); err == nil {
addrs = append(addrs, t...)
}
}
} else {
addrs = append(addrs, addr)
}
}
seen = append(seen, addrs...)
for _, addr := range addrs {
uri, err := url.Parse(addr)
if err != nil {
l.Infoln("Failed to parse connection url:", addr, err)
continue
}
dialerFactory, ok := dialers[uri.Scheme]
if !ok {
l.Debugln("Unknown address schema", uri)
continue
}
dialer := dialerFactory(s.cfg, s.tlsCfg)
nextDialAt, ok := nextDial[uri.String()]
// See below for comments on this delay >= sleep check
if delay >= sleep && ok && nextDialAt.After(now) {
l.Debugf("Not dialing as next dial is at %s and current time is %s", nextDialAt, now)
continue
}
nextDial[uri.String()] = now.Add(dialer.RedialFrequency())
if connected && dialer.Priority() >= ct.Priority {
l.Debugf("Not dialing using %s as priorty is less than current connection (%d >= %d)", dialer, dialer.Priority(), ct.Priority)
continue
}
l.Debugln("dial", deviceCfg.DeviceID, uri)
conn, err := dialer.Dial(deviceID, uri)
if err != nil {
l.Debugln("dial failed", deviceCfg.DeviceID, uri, err)
continue
}
if connected {
s.model.Close(deviceID, protocol.ErrSwitchingConnections)
}
s.conns <- conn
continue nextDevice
}
}
nextDial, sleep = filterAndFindSleepDuration(nextDial, seen, now)
// delay variable is used to trigger much more frequent dialing after
// initial startup, essentially causing redials every 1, 2, 4, 8... seconds
if delay < sleep {
time.Sleep(delay)
delay *= 2
} else {
time.Sleep(sleep)
}
}
}
func (s *Service) shouldLimit(addr net.Addr) bool {
if s.cfg.Options().LimitBandwidthInLan {
return true
}
tcpaddr, ok := addr.(*net.TCPAddr)
if !ok {
return true
}
for _, lan := range s.lans {
if lan.Contains(tcpaddr.IP) {
return false
}
}
return !tcpaddr.IP.IsLoopback()
}
func (s *Service) createListener(addr string) {
uri, err := url.Parse(addr)
if err != nil {
l.Infoln("Failed to parse listen address:", addr, err)
return
}
listenerFactory, ok := listeners[uri.Scheme]
if !ok {
l.Infoln("Unknown listen address scheme:", uri.String())
return
}
listener := listenerFactory(uri, s.tlsCfg, s.conns, s.natService)
listener.OnAddressesChanged(s.logListenAddressesChangedEvent)
s.mut.Lock()
s.listeners[addr] = listener
s.listenerTokens[addr] = s.Add(listener)
s.mut.Unlock()
}
func (s *Service) logListenAddressesChangedEvent(l genericListener) {
events.Default.Log(events.ListenAddressesChanged, map[string]interface{}{
"address": l.URI(),
"lan": l.LANAddresses(),
"wan": l.WANAddresses(),
})
}
func (s *Service) VerifyConfiguration(from, to config.Configuration) error {
return nil
}
func (s *Service) CommitConfiguration(from, to config.Configuration) bool {
// We require a restart if a device as been removed.
restart := false
newDevices := make(map[protocol.DeviceID]bool, len(to.Devices))
for _, dev := range to.Devices {
newDevices[dev.DeviceID] = true
}
for _, dev := range from.Devices {
if !newDevices[dev.DeviceID] {
restart = true
}
}
s.mut.RLock()
existingListeners := s.listeners
s.mut.RUnlock()
seen := make(map[string]struct{})
for _, addr := range config.Wrap("", to).ListenAddresses() {
if _, ok := existingListeners[addr]; !ok {
l.Debugln("Staring listener", addr)
s.createListener(addr)
}
seen[addr] = struct{}{}
}
s.mut.Lock()
for addr := range s.listeners {
if _, ok := seen[addr]; !ok {
l.Debugln("Stopping listener", addr)
s.Remove(s.listenerTokens[addr])
delete(s.listenerTokens, addr)
delete(s.listeners, addr)
}
}
s.mut.Unlock()
if to.Options.NATEnabled && s.natServiceToken == nil {
l.Debugln("Starting NAT service")
token := s.Add(s.natService)
s.natServiceToken = &token
} else if !to.Options.NATEnabled && s.natServiceToken != nil {
l.Debugln("Stopping NAT service")
s.Remove(*s.natServiceToken)
s.natServiceToken = nil
}
return !restart
}
func (s *Service) AllAddresses() []string {
s.mut.RLock()
var addrs []string
for _, listener := range s.listeners {
for _, lanAddr := range listener.LANAddresses() {
addrs = append(addrs, lanAddr.String())
}
for _, wanAddr := range listener.WANAddresses() {
addrs = append(addrs, wanAddr.String())
}
}
s.mut.RUnlock()
return util.UniqueStrings(addrs)
}
func (s *Service) ExternalAddresses() []string {
s.mut.RLock()
var addrs []string
for _, listener := range s.listeners {
for _, wanAddr := range listener.WANAddresses() {
addrs = append(addrs, wanAddr.String())
}
}
s.mut.RUnlock()
return util.UniqueStrings(addrs)
}
func (s *Service) Status() map[string]interface{} {
s.mut.RLock()
result := make(map[string]interface{})
for addr, listener := range s.listeners {
status := make(map[string]interface{})
err := listener.Error()
if err != nil {
status["error"] = err.Error()
}
status["lanAddresses"] = urlsToStrings(listener.LANAddresses())
status["wanAddresses"] = urlsToStrings(listener.WANAddresses())
result[addr] = status
}
s.mut.RUnlock()
return result
}
func exchangeHello(c net.Conn, h protocol.HelloMessage) (protocol.HelloMessage, error) {
if err := c.SetDeadline(time.Now().Add(2 * time.Second)); err != nil {
return protocol.HelloMessage{}, err
}
defer c.SetDeadline(time.Time{})
header := make([]byte, 8)
msg := h.MustMarshalXDR()
binary.BigEndian.PutUint32(header[:4], protocol.HelloMessageMagic)
binary.BigEndian.PutUint32(header[4:], uint32(len(msg)))
if _, err := c.Write(header); err != nil {
return protocol.HelloMessage{}, err
}
if _, err := c.Write(msg); err != nil {
return protocol.HelloMessage{}, err
}
if _, err := io.ReadFull(c, header); err != nil {
return protocol.HelloMessage{}, err
}
if binary.BigEndian.Uint32(header[:4]) != protocol.HelloMessageMagic {
return protocol.HelloMessage{}, fmt.Errorf("incorrect magic")
}
msgSize := binary.BigEndian.Uint32(header[4:])
if msgSize > 1024 {
return protocol.HelloMessage{}, fmt.Errorf("hello message too big")
}
buf := make([]byte, msgSize)
var hello protocol.HelloMessage
if _, err := io.ReadFull(c, buf); err != nil {
return protocol.HelloMessage{}, err
}
if err := hello.UnmarshalXDR(buf); err != nil {
return protocol.HelloMessage{}, err
}
return hello, nil
}
func filterAndFindSleepDuration(nextDial map[string]time.Time, seen []string, now time.Time) (map[string]time.Time, time.Duration) {
newNextDial := make(map[string]time.Time)
for _, addr := range seen {
nextDialAt, ok := nextDial[addr]
if ok {
newNextDial[addr] = nextDialAt
}
}
min := time.Minute
for _, next := range newNextDial {
cur := next.Sub(now)
if cur < min {
min = cur
}
}
return newNextDial, min
}
func urlsToStrings(urls []*url.URL) []string {
strings := make([]string, len(urls))
for i, url := range urls {
strings[i] = url.String()
}
return strings
}

88
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// Copyright (C) 2016 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 connections
import (
"crypto/tls"
"net"
"net/url"
"time"
"github.com/syncthing/syncthing/lib/config"
"github.com/syncthing/syncthing/lib/nat"
"github.com/syncthing/syncthing/lib/protocol"
)
type IntermediateConnection struct {
*tls.Conn
Type string
Priority int
}
type Connection struct {
IntermediateConnection
protocol.Connection
}
type dialerFactory func(*config.Wrapper, *tls.Config) genericDialer
type genericDialer interface {
Dial(protocol.DeviceID, *url.URL) (IntermediateConnection, error)
Priority() int
RedialFrequency() time.Duration
String() string
}
type listenerFactory func(*url.URL, *tls.Config, chan IntermediateConnection, *nat.Service) genericListener
type genericListener interface {
Serve()
Stop()
URI() *url.URL
// A given address can potentially be mutated by the listener.
// For example we bind to tcp://0.0.0.0, but that for example might return
// tcp://gateway1.ip and tcp://gateway2.ip as WAN addresses due to there
// being multiple gateways, and us managing to get a UPnP mapping on both
// and tcp://192.168.0.1 and tcp://10.0.0.1 due to there being multiple
// network interfaces. (The later case for LAN addresses is made up just
// to provide an example)
WANAddresses() []*url.URL
LANAddresses() []*url.URL
Error() error
OnAddressesChanged(func(genericListener))
String() string
}
type Model interface {
protocol.Model
AddConnection(conn Connection, hello protocol.HelloMessage)
ConnectedTo(remoteID protocol.DeviceID) bool
IsPaused(remoteID protocol.DeviceID) bool
OnHello(protocol.DeviceID, net.Addr, protocol.HelloMessage)
GetHello(protocol.DeviceID) protocol.HelloMessage
}
// serviceFunc wraps a function to create a suture.Service without stop
// functionality.
type serviceFunc func()
func (f serviceFunc) Serve() { f() }
func (f serviceFunc) Stop() {}
type onAddressesChangedNotifier struct {
callbacks []func(genericListener)
}
func (o *onAddressesChangedNotifier) OnAddressesChanged(callback func(genericListener)) {
o.callbacks = append(o.callbacks, callback)
}
func (o *onAddressesChangedNotifier) notifyAddressesChanged(l genericListener) {
for _, callback := range o.callbacks {
callback(l)
}
}

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lib/connections/tcp_dial.go Normal file
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// Copyright (C) 2016 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 connections
import (
"crypto/tls"
"net"
"net/url"
"time"
"github.com/syncthing/syncthing/lib/config"
"github.com/syncthing/syncthing/lib/dialer"
"github.com/syncthing/syncthing/lib/protocol"
)
const tcpPriority = 10
func init() {
for _, scheme := range []string{"tcp", "tcp4", "tcp6"} {
dialers[scheme] = newTCPDialer
}
}
type tcpDialer struct {
cfg *config.Wrapper
tlsCfg *tls.Config
}
func (d *tcpDialer) Dial(id protocol.DeviceID, uri *url.URL) (IntermediateConnection, error) {
uri = fixupPort(uri)
raddr, err := net.ResolveTCPAddr(uri.Scheme, uri.Host)
if err != nil {
l.Debugln(err)
return IntermediateConnection{}, err
}
conn, err := dialer.DialTimeout(raddr.Network(), raddr.String(), 10*time.Second)
if err != nil {
l.Debugln(err)
return IntermediateConnection{}, err
}
tc := tls.Client(conn, d.tlsCfg)
err = tc.Handshake()
if err != nil {
tc.Close()
return IntermediateConnection{}, err
}
return IntermediateConnection{tc, "TCP (Client)", tcpPriority}, nil
}
func (tcpDialer) Priority() int {
return tcpPriority
}
func (d *tcpDialer) RedialFrequency() time.Duration {
return time.Duration(d.cfg.Options().ReconnectIntervalS) * time.Second
}
func (d *tcpDialer) String() string {
return "TCP Dialer"
}
func newTCPDialer(cfg *config.Wrapper, tlsCfg *tls.Config) genericDialer {
return &tcpDialer{
cfg: cfg,
tlsCfg: tlsCfg,
}
}

213
lib/connections/tcp_listen.go Normal file
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// Copyright (C) 2016 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 connections
import (
"crypto/tls"
"net"
"net/url"
"strings"
"sync"
"time"
"github.com/syncthing/syncthing/lib/dialer"
"github.com/syncthing/syncthing/lib/nat"
)
func init() {
for _, scheme := range []string{"tcp", "tcp4", "tcp6"} {
listeners[scheme] = newTCPListener
}
}
type tcpListener struct {
onAddressesChangedNotifier
uri *url.URL
tlsCfg *tls.Config
stop chan struct{}
conns chan IntermediateConnection
natService *nat.Service
mapping *nat.Mapping
address *url.URL
err error
mut sync.RWMutex
}
func (t *tcpListener) Serve() {
t.mut.Lock()
t.err = nil
t.mut.Unlock()
tcaddr, err := net.ResolveTCPAddr(t.uri.Scheme, t.uri.Host)
if err != nil {
t.mut.Lock()
t.err = err
t.mut.Unlock()
l.Infoln("listen (BEP/tcp):", err)
return
}
listener, err := net.ListenTCP(t.uri.Scheme, tcaddr)
if err != nil {
t.mut.Lock()
t.err = err
t.mut.Unlock()
l.Infoln("listen (BEP/tcp):", err)
return
}
defer listener.Close()
mapping := t.natService.NewMapping(nat.TCP, tcaddr.IP, tcaddr.Port)
mapping.OnChanged(func(_ *nat.Mapping, _, _ []nat.Address) {
t.notifyAddressesChanged(t)
})
defer t.natService.RemoveMapping(mapping)
t.mut.Lock()
t.mapping = mapping
t.mut.Unlock()
for {
listener.SetDeadline(time.Now().Add(time.Second))
conn, err := listener.Accept()
select {
case <-t.stop:
if err == nil {
conn.Close()
}
t.mut.Lock()
t.mapping = nil
t.mut.Unlock()
return
default:
}
if err != nil {
if err, ok := err.(*net.OpError); !ok || !err.Timeout() {
l.Warnln("Accepting connection (BEP/tcp):", err)
}
continue
}
l.Debugln("connect from", conn.RemoteAddr())
err = dialer.SetTCPOptions(conn.(*net.TCPConn))
if err != nil {
l.Infoln(err)
}
tc := tls.Server(conn, t.tlsCfg)
err = tc.Handshake()
if err != nil {
l.Infoln("TLS handshake (BEP/tcp):", err)
tc.Close()
continue
}
t.conns <- IntermediateConnection{tc, "TCP (Server)", tcpPriority}
}
}
func (t *tcpListener) Stop() {
close(t.stop)
}
func (t *tcpListener) URI() *url.URL {
return t.uri
}
func (t *tcpListener) WANAddresses() []*url.URL {
uris := t.LANAddresses()
t.mut.RLock()
if t.mapping != nil {
addrs := t.mapping.ExternalAddresses()
for _, addr := range addrs {
uri := *t.uri
// Does net.JoinHostPort internally
uri.Host = addr.String()
uris = append(uris, &uri)
}
}
t.mut.RUnlock()
return uris
}
func (t *tcpListener) LANAddresses() []*url.URL {
return []*url.URL{t.uri}
}
func (t *tcpListener) Error() error {
t.mut.RLock()
err := t.err
t.mut.RUnlock()
return err
}
func (t *tcpListener) String() string {
return t.uri.String()
}
func newTCPListener(uri *url.URL, tlsCfg *tls.Config, conns chan IntermediateConnection, natService *nat.Service) genericListener {
return &tcpListener{
uri: fixupPort(uri),
tlsCfg: tlsCfg,
conns: conns,
natService: natService,
stop: make(chan struct{}),
}
}
func isPublicIPv4(ip net.IP) bool {
ip = ip.To4()
if ip == nil {
// Not an IPv4 address (IPv6)
return false
}
// IsGlobalUnicast below only checks that it's not link local or
// multicast, and we want to exclude private (NAT:ed) addresses as well.
rfc1918 := []net.IPNet{
{IP: net.IP{10, 0, 0, 0}, Mask: net.IPMask{255, 0, 0, 0}},
{IP: net.IP{172, 16, 0, 0}, Mask: net.IPMask{255, 240, 0, 0}},
{IP: net.IP{192, 168, 0, 0}, Mask: net.IPMask{255, 255, 0, 0}},
}
for _, n := range rfc1918 {
if n.Contains(ip) {
return false
}
}
return ip.IsGlobalUnicast()
}
func isPublicIPv6(ip net.IP) bool {
if ip.To4() != nil {
// Not an IPv6 address (IPv4)
// (To16() returns a v6 mapped v4 address so can't be used to check
// that it's an actual v6 address)
return false
}
return ip.IsGlobalUnicast()
}
func fixupPort(uri *url.URL) *url.URL {
copyURI := *uri
host, port, err := net.SplitHostPort(uri.Host)
if err != nil && strings.HasPrefix(err.Error(), "missing port") {
// addr is on the form "1.2.3.4"
copyURI.Host = net.JoinHostPort(host, "22000")
} else if err == nil && port == "" {
// addr is on the form "1.2.3.4:"
copyURI.Host = net.JoinHostPort(host, "22000")
}
return &copyURI
}