22 "github.com/anacrolix/chansync"
23 "github.com/anacrolix/chansync/events"
24 "github.com/anacrolix/dht/v2"
25 "github.com/anacrolix/dht/v2/krpc"
26 . "github.com/anacrolix/generics"
27 g "github.com/anacrolix/generics"
28 "github.com/anacrolix/log"
29 "github.com/anacrolix/missinggo/perf"
30 "github.com/anacrolix/missinggo/v2"
31 "github.com/anacrolix/missinggo/v2/bitmap"
32 "github.com/anacrolix/missinggo/v2/pproffd"
33 "github.com/anacrolix/sync"
34 "github.com/davecgh/go-spew/spew"
35 "github.com/dustin/go-humanize"
36 gbtree "github.com/google/btree"
37 "github.com/pion/datachannel"
39 "github.com/anacrolix/torrent/bencode"
40 "github.com/anacrolix/torrent/internal/check"
41 "github.com/anacrolix/torrent/internal/limiter"
42 "github.com/anacrolix/torrent/iplist"
43 "github.com/anacrolix/torrent/metainfo"
44 "github.com/anacrolix/torrent/mse"
45 pp "github.com/anacrolix/torrent/peer_protocol"
46 utHolepunch "github.com/anacrolix/torrent/peer_protocol/ut-holepunch"
47 request_strategy "github.com/anacrolix/torrent/request-strategy"
48 "github.com/anacrolix/torrent/storage"
49 "github.com/anacrolix/torrent/tracker"
50 "github.com/anacrolix/torrent/types/infohash"
51 "github.com/anacrolix/torrent/webtorrent"
54 // Clients contain zero or more Torrents. A Client manages a blocklist, the
55 // TCP/UDP protocol ports, and DHT as desired.
57 // An aggregate of stats over all connections. First in struct to ensure 64-bit alignment of
63 closed chansync.SetOnce
69 defaultStorage *storage.Client
73 dhtServers []DhtServer
74 ipBlockList iplist.Ranger
76 // Set of addresses that have our client ID. This intentionally will
77 // include ourselves if we end up trying to connect to our own address
78 // through legitimate channels.
79 dopplegangerAddrs map[string]struct{}
80 badPeerIPs map[netip.Addr]struct{}
81 torrents map[InfoHash]*Torrent
82 pieceRequestOrder map[interface{}]*request_strategy.PieceRequestOrder
84 acceptLimiter map[ipStr]int
87 websocketTrackers websocketTrackers
89 activeAnnounceLimiter limiter.Instance
90 httpClient *http.Client
92 clientHolepunchAddrSets
97 func (cl *Client) BadPeerIPs() (ips []string) {
99 ips = cl.badPeerIPsLocked()
104 func (cl *Client) badPeerIPsLocked() (ips []string) {
105 ips = make([]string, len(cl.badPeerIPs))
107 for k := range cl.badPeerIPs {
114 func (cl *Client) PeerID() PeerID {
118 // Returns the port number for the first listener that has one. No longer assumes that all port
119 // numbers are the same, due to support for custom listeners. Returns zero if no port number is
121 func (cl *Client) LocalPort() (port int) {
122 for i := 0; i < len(cl.listeners); i += 1 {
123 if port = addrPortOrZero(cl.listeners[i].Addr()); port != 0 {
130 func writeDhtServerStatus(w io.Writer, s DhtServer) {
131 dhtStats := s.Stats()
132 fmt.Fprintf(w, " ID: %x\n", s.ID())
133 spew.Fdump(w, dhtStats)
136 // Writes out a human readable status of the client, such as for writing to a
138 func (cl *Client) WriteStatus(_w io.Writer) {
141 w := bufio.NewWriter(_w)
143 fmt.Fprintf(w, "Listen port: %d\n", cl.LocalPort())
144 fmt.Fprintf(w, "Peer ID: %+q\n", cl.PeerID())
145 fmt.Fprintf(w, "Extension bits: %v\n", cl.config.Extensions)
146 fmt.Fprintf(w, "Announce key: %x\n", cl.announceKey())
147 fmt.Fprintf(w, "Banned IPs: %d\n", len(cl.badPeerIPsLocked()))
148 cl.eachDhtServer(func(s DhtServer) {
149 fmt.Fprintf(w, "%s DHT server at %s:\n", s.Addr().Network(), s.Addr().String())
150 writeDhtServerStatus(w, s)
152 dumpStats(w, cl.statsLocked())
153 torrentsSlice := cl.torrentsAsSlice()
154 fmt.Fprintf(w, "# Torrents: %d\n", len(torrentsSlice))
156 sort.Slice(torrentsSlice, func(l, r int) bool {
157 return torrentsSlice[l].infoHash.AsString() < torrentsSlice[r].infoHash.AsString()
159 for _, t := range torrentsSlice {
161 fmt.Fprint(w, "<unknown name>")
163 fmt.Fprint(w, t.name())
169 "%f%% of %d bytes (%s)",
170 100*(1-float64(t.bytesMissingLocked())/float64(t.info.TotalLength())),
172 humanize.Bytes(uint64(t.length())))
174 w.WriteString("<missing metainfo>")
182 func (cl *Client) initLogger() {
183 logger := cl.config.Logger
188 logger = logger.FilterLevel(log.Debug)
190 cl.logger = logger.WithValues(cl)
193 func (cl *Client) announceKey() int32 {
194 return int32(binary.BigEndian.Uint32(cl.peerID[16:20]))
197 // Initializes a bare minimum Client. *Client and *ClientConfig must not be nil.
198 func (cl *Client) init(cfg *ClientConfig) {
200 g.MakeMap(&cl.dopplegangerAddrs)
201 cl.torrents = make(map[metainfo.Hash]*Torrent)
202 cl.activeAnnounceLimiter.SlotsPerKey = 2
203 cl.event.L = cl.locker()
204 cl.ipBlockList = cfg.IPBlocklist
205 cl.httpClient = &http.Client{
206 Transport: cfg.WebTransport,
208 if cl.httpClient.Transport == nil {
209 cl.httpClient.Transport = &http.Transport{
210 Proxy: cfg.HTTPProxy,
211 DialContext: cfg.HTTPDialContext,
212 // I think this value was observed from some webseeds. It seems reasonable to extend it
213 // to other uses of HTTP from the client.
219 func NewClient(cfg *ClientConfig) (cl *Client, err error) {
221 cfg = NewDefaultClientConfig()
227 go cl.acceptLimitClearer()
236 storageImpl := cfg.DefaultStorage
237 if storageImpl == nil {
238 // We'd use mmap by default but HFS+ doesn't support sparse files.
239 storageImplCloser := storage.NewFile(cfg.DataDir)
240 cl.onClose = append(cl.onClose, func() {
241 if err := storageImplCloser.Close(); err != nil {
242 cl.logger.Printf("error closing default storage: %s", err)
245 storageImpl = storageImplCloser
247 cl.defaultStorage = storage.NewClient(storageImpl)
249 if cfg.PeerID != "" {
250 missinggo.CopyExact(&cl.peerID, cfg.PeerID)
252 o := copy(cl.peerID[:], cfg.Bep20)
253 _, err = rand.Read(cl.peerID[o:])
255 panic("error generating peer id")
259 sockets, err := listenAll(cl.listenNetworks(), cl.config.ListenHost, cl.config.ListenPort, cl.firewallCallback, cl.logger)
267 for _, _s := range sockets {
268 s := _s // Go is fucking retarded.
269 cl.onClose = append(cl.onClose, func() { go s.Close() })
270 if peerNetworkEnabled(parseNetworkString(s.Addr().Network()), cl.config) {
271 cl.dialers = append(cl.dialers, s)
272 cl.listeners = append(cl.listeners, s)
273 if cl.config.AcceptPeerConnections {
274 go cl.acceptConnections(s)
281 for _, s := range sockets {
282 if pc, ok := s.(net.PacketConn); ok {
283 ds, err := cl.NewAnacrolixDhtServer(pc)
287 cl.dhtServers = append(cl.dhtServers, AnacrolixDhtServerWrapper{ds})
288 cl.onClose = append(cl.onClose, func() { ds.Close() })
293 cl.websocketTrackers = websocketTrackers{
296 GetAnnounceRequest: func(event tracker.AnnounceEvent, infoHash [20]byte) (tracker.AnnounceRequest, error) {
299 t, ok := cl.torrents[infoHash]
301 return tracker.AnnounceRequest{}, errors.New("torrent not tracked by client")
303 return t.announceRequest(event), nil
305 Proxy: cl.config.HTTPProxy,
306 WebsocketTrackerHttpHeader: cl.config.WebsocketTrackerHttpHeader,
307 ICEServers: cl.config.ICEServers,
308 DialContext: cl.config.TrackerDialContext,
309 OnConn: func(dc datachannel.ReadWriteCloser, dcc webtorrent.DataChannelContext) {
312 t, ok := cl.torrents[dcc.InfoHash]
314 cl.logger.WithDefaultLevel(log.Warning).Printf(
315 "got webrtc conn for unloaded torrent with infohash %x",
321 go t.onWebRtcConn(dc, dcc)
328 func (cl *Client) AddDhtServer(d DhtServer) {
329 cl.dhtServers = append(cl.dhtServers, d)
332 // Adds a Dialer for outgoing connections. All Dialers are used when attempting to connect to a
333 // given address for any Torrent.
334 func (cl *Client) AddDialer(d Dialer) {
337 cl.dialers = append(cl.dialers, d)
338 for _, t := range cl.torrents {
343 func (cl *Client) Listeners() []Listener {
347 // Registers a Listener, and starts Accepting on it. You must Close Listeners provided this way
349 func (cl *Client) AddListener(l Listener) {
350 cl.listeners = append(cl.listeners, l)
351 if cl.config.AcceptPeerConnections {
352 go cl.acceptConnections(l)
356 func (cl *Client) firewallCallback(net.Addr) bool {
358 block := !cl.wantConns() || !cl.config.AcceptPeerConnections
361 torrent.Add("connections firewalled", 1)
363 torrent.Add("connections not firewalled", 1)
368 func (cl *Client) listenOnNetwork(n network) bool {
369 if n.Ipv4 && cl.config.DisableIPv4 {
372 if n.Ipv6 && cl.config.DisableIPv6 {
375 if n.Tcp && cl.config.DisableTCP {
378 if n.Udp && cl.config.DisableUTP && cl.config.NoDHT {
384 func (cl *Client) listenNetworks() (ns []network) {
385 for _, n := range allPeerNetworks {
386 if cl.listenOnNetwork(n) {
393 // Creates an anacrolix/dht Server, as would be done internally in NewClient, for the given conn.
394 func (cl *Client) NewAnacrolixDhtServer(conn net.PacketConn) (s *dht.Server, err error) {
395 logger := cl.logger.WithNames("dht", conn.LocalAddr().String())
396 cfg := dht.ServerConfig{
397 IPBlocklist: cl.ipBlockList,
399 OnAnnouncePeer: cl.onDHTAnnouncePeer,
400 PublicIP: func() net.IP {
401 if connIsIpv6(conn) && cl.config.PublicIp6 != nil {
402 return cl.config.PublicIp6
404 return cl.config.PublicIp4
406 StartingNodes: cl.config.DhtStartingNodes(conn.LocalAddr().Network()),
407 OnQuery: cl.config.DHTOnQuery,
410 if f := cl.config.ConfigureAnacrolixDhtServer; f != nil {
413 s, err = dht.NewServer(&cfg)
415 go s.TableMaintainer()
420 func (cl *Client) Closed() events.Done {
421 return cl.closed.Done()
424 func (cl *Client) eachDhtServer(f func(DhtServer)) {
425 for _, ds := range cl.dhtServers {
430 // Stops the client. All connections to peers are closed and all activity will come to a halt.
431 func (cl *Client) Close() (errs []error) {
432 var closeGroup sync.WaitGroup // For concurrent cleanup to complete before returning
434 for _, t := range cl.torrents {
435 err := t.close(&closeGroup)
437 errs = append(errs, err)
440 for i := range cl.onClose {
441 cl.onClose[len(cl.onClose)-1-i]()
446 closeGroup.Wait() // defer is LIFO. We want to Wait() after cl.unlock()
450 func (cl *Client) ipBlockRange(ip net.IP) (r iplist.Range, blocked bool) {
451 if cl.ipBlockList == nil {
454 return cl.ipBlockList.Lookup(ip)
457 func (cl *Client) ipIsBlocked(ip net.IP) bool {
458 _, blocked := cl.ipBlockRange(ip)
462 func (cl *Client) wantConns() bool {
463 if cl.config.AlwaysWantConns {
466 for _, t := range cl.torrents {
467 if t.wantIncomingConns() {
474 // TODO: Apply filters for non-standard networks, particularly rate-limiting.
475 func (cl *Client) rejectAccepted(conn net.Conn) error {
477 return errors.New("don't want conns right now")
479 ra := conn.RemoteAddr()
480 if rip := addrIpOrNil(ra); rip != nil {
481 if cl.config.DisableIPv4Peers && rip.To4() != nil {
482 return errors.New("ipv4 peers disabled")
484 if cl.config.DisableIPv4 && len(rip) == net.IPv4len {
485 return errors.New("ipv4 disabled")
487 if cl.config.DisableIPv6 && len(rip) == net.IPv6len && rip.To4() == nil {
488 return errors.New("ipv6 disabled")
490 if cl.rateLimitAccept(rip) {
491 return errors.New("source IP accepted rate limited")
493 if cl.badPeerIPPort(rip, missinggo.AddrPort(ra)) {
494 return errors.New("bad source addr")
500 func (cl *Client) acceptConnections(l Listener) {
502 conn, err := l.Accept()
503 torrent.Add("client listener accepts", 1)
505 holepunchAddr, holepunchErr := addrPortFromPeerRemoteAddr(conn.RemoteAddr())
506 if holepunchErr == nil {
508 if g.MapContains(cl.undialableWithoutHolepunch, holepunchAddr) {
509 setAdd(&cl.accepted, holepunchAddr)
512 cl.undialableWithoutHolepunchDialedAfterHolepunchConnect,
515 setAdd(&cl.probablyOnlyConnectedDueToHolepunch, holepunchAddr)
520 conn = pproffd.WrapNetConn(conn)
522 closed := cl.closed.IsSet()
524 if !closed && conn != nil {
525 reject = cl.rejectAccepted(conn)
535 log.Fmsg("error accepting connection: %s", err).LogLevel(log.Debug, cl.logger)
540 torrent.Add("rejected accepted connections", 1)
541 cl.logger.LazyLog(log.Debug, func() log.Msg {
542 return log.Fmsg("rejecting accepted conn: %v", reject)
546 go cl.incomingConnection(conn)
548 cl.logger.LazyLog(log.Debug, func() log.Msg {
549 return log.Fmsg("accepted %q connection at %q from %q",
555 torrent.Add(fmt.Sprintf("accepted conn remote IP len=%d", len(addrIpOrNil(conn.RemoteAddr()))), 1)
556 torrent.Add(fmt.Sprintf("accepted conn network=%s", conn.RemoteAddr().Network()), 1)
557 torrent.Add(fmt.Sprintf("accepted on %s listener", l.Addr().Network()), 1)
562 // Creates the PeerConn.connString for a regular net.Conn PeerConn.
563 func regularNetConnPeerConnConnString(nc net.Conn) string {
564 return fmt.Sprintf("%s-%s", nc.LocalAddr(), nc.RemoteAddr())
567 func (cl *Client) incomingConnection(nc net.Conn) {
569 if tc, ok := nc.(*net.TCPConn); ok {
572 remoteAddr, _ := tryIpPortFromNetAddr(nc.RemoteAddr())
573 c := cl.newConnection(
577 remoteAddr: nc.RemoteAddr(),
578 localPublicAddr: cl.publicAddr(remoteAddr.IP),
579 network: nc.RemoteAddr().Network(),
580 connString: regularNetConnPeerConnConnString(nc),
587 c.Discovery = PeerSourceIncoming
588 cl.runReceivedConn(c)
591 // Returns a handle to the given torrent, if it's present in the client.
592 func (cl *Client) Torrent(ih metainfo.Hash) (t *Torrent, ok bool) {
595 t, ok = cl.torrents[ih]
599 func (cl *Client) torrent(ih metainfo.Hash) *Torrent {
600 return cl.torrents[ih]
603 type DialResult struct {
608 func countDialResult(err error) {
610 torrent.Add("successful dials", 1)
612 torrent.Add("unsuccessful dials", 1)
616 func reducedDialTimeout(minDialTimeout, max time.Duration, halfOpenLimit, pendingPeers int) (ret time.Duration) {
617 ret = max / time.Duration((pendingPeers+halfOpenLimit)/halfOpenLimit)
618 if ret < minDialTimeout {
624 // Returns whether an address is known to connect to a client with our own ID.
625 func (cl *Client) dopplegangerAddr(addr string) bool {
626 _, ok := cl.dopplegangerAddrs[addr]
630 // Returns a connection over UTP or TCP, whichever is first to connect.
631 func (cl *Client) dialFirst(ctx context.Context, addr string) (res DialResult) {
632 return DialFirst(ctx, addr, cl.dialers)
635 // Returns a connection over UTP or TCP, whichever is first to connect.
636 func DialFirst(ctx context.Context, addr string, dialers []Dialer) (res DialResult) {
640 defer pool.startDrainer()
641 for _, _s := range dialers {
644 return pool.getFirst()
647 func dialFromSocket(ctx context.Context, s Dialer, addr string) net.Conn {
648 c, err := s.Dial(ctx, addr)
650 log.Levelf(log.Debug, "error dialing %q: %v", addr, err)
652 // This is a bit optimistic, but it looks non-trivial to thread this through the proxy code. Set
653 // it now in case we close the connection forthwith. Note this is also done in the TCP dialer
654 // code to increase the chance it's done.
655 if tc, ok := c.(*net.TCPConn); ok {
662 func (cl *Client) noLongerHalfOpen(t *Torrent, addr string, attemptKey outgoingConnAttemptKey) {
663 path := t.getHalfOpenPath(addr, attemptKey)
665 panic("should exist")
669 if cl.numHalfOpen < 0 {
670 panic("should not be possible")
672 for _, t := range cl.torrents {
677 func (cl *Client) countHalfOpenFromTorrents() (count int) {
678 for _, t := range cl.torrents {
679 count += t.numHalfOpenAttempts()
684 // Performs initiator handshakes and returns a connection. Returns nil *PeerConn if no connection
685 // for valid reasons.
686 func (cl *Client) initiateProtocolHandshakes(
691 newConnOpts newConnectionOpts,
693 c *PeerConn, err error,
695 c = cl.newConnection(nc, newConnOpts)
696 c.headerEncrypted = encryptHeader
697 ctx, cancel := context.WithTimeout(ctx, cl.config.HandshakesTimeout)
699 dl, ok := ctx.Deadline()
703 err = nc.SetDeadline(dl)
707 err = cl.initiateHandshakes(c, t)
711 func doProtocolHandshakeOnDialResult(
713 obfuscatedHeader bool,
717 c *PeerConn, err error,
721 addrIpPort, _ := tryIpPortFromNetAddr(addr)
722 c, err = cl.initiateProtocolHandshakes(
723 context.Background(), nc, t, obfuscatedHeader,
727 // It would be possible to retrieve a public IP from the dialer used here?
728 localPublicAddr: cl.publicAddr(addrIpPort.IP),
729 network: dr.Dialer.DialerNetwork(),
730 connString: regularNetConnPeerConnConnString(nc),
738 // Returns nil connection and nil error if no connection could be established for valid reasons.
739 func (cl *Client) dialAndCompleteHandshake(opts outgoingConnOpts) (c *PeerConn, err error) {
740 // It would be better if dial rate limiting could be tested when considering to open connections
741 // instead. Doing it here means if the limit is low, and the half-open limit is high, we could
742 // end up with lots of outgoing connection attempts pending that were initiated on stale data.
744 dialReservation := cl.config.DialRateLimiter.Reserve()
745 if !opts.receivedHolepunchConnect {
746 if !dialReservation.OK() {
747 err = errors.New("can't make dial limit reservation")
750 time.Sleep(dialReservation.Delay())
753 torrent.Add("establish outgoing connection", 1)
754 addr := opts.peerInfo.Addr
755 dialPool := dialPool{
756 resCh: make(chan DialResult),
759 defer dialPool.startDrainer()
760 dialTimeout := opts.t.getDialTimeoutUnlocked()
762 ctx, cancel := context.WithTimeout(context.Background(), dialTimeout)
764 for _, d := range cl.dialers {
768 holepunchAddr, holepunchAddrErr := addrPortFromPeerRemoteAddr(addr)
769 headerObfuscationPolicy := opts.HeaderObfuscationPolicy
770 obfuscatedHeaderFirst := headerObfuscationPolicy.Preferred
771 firstDialResult := dialPool.getFirst()
772 if firstDialResult.Conn == nil {
773 // No dialers worked. Try to initiate a holepunching rendezvous.
774 if holepunchAddrErr == nil {
776 if !opts.receivedHolepunchConnect {
777 g.MakeMapIfNilAndSet(&cl.undialableWithoutHolepunch, holepunchAddr, struct{}{})
779 if !opts.skipHolepunchRendezvous {
780 opts.t.trySendHolepunchRendezvous(holepunchAddr)
784 err = fmt.Errorf("all initial dials failed")
787 if opts.receivedHolepunchConnect && holepunchAddrErr == nil {
789 if g.MapContains(cl.undialableWithoutHolepunch, holepunchAddr) {
790 g.MakeMapIfNilAndSet(&cl.dialableOnlyAfterHolepunch, holepunchAddr, struct{}{})
792 g.MakeMapIfNil(&cl.dialedSuccessfullyAfterHolepunchConnect)
793 g.MapInsert(cl.dialedSuccessfullyAfterHolepunchConnect, holepunchAddr, struct{}{})
796 c, err = doProtocolHandshakeOnDialResult(
798 obfuscatedHeaderFirst,
803 torrent.Add("initiated conn with preferred header obfuscation", 1)
808 "error doing protocol handshake with header obfuscation %v",
809 obfuscatedHeaderFirst,
811 firstDialResult.Conn.Close()
812 // We should have just tried with the preferred header obfuscation. If it was required, there's nothing else to try.
813 if headerObfuscationPolicy.RequirePreferred {
816 // Reuse the dialer that returned already but failed to handshake.
818 ctx, cancel := context.WithTimeout(context.Background(), dialTimeout)
820 dialPool.add(ctx, firstDialResult.Dialer)
822 secondDialResult := dialPool.getFirst()
823 if secondDialResult.Conn == nil {
826 c, err = doProtocolHandshakeOnDialResult(
828 !obfuscatedHeaderFirst,
833 torrent.Add("initiated conn with fallback header obfuscation", 1)
838 "error doing protocol handshake with header obfuscation %v",
839 !obfuscatedHeaderFirst,
841 secondDialResult.Conn.Close()
845 type outgoingConnOpts struct {
848 // Don't attempt to connect unless a connect message is received after initiating a rendezvous.
849 requireRendezvous bool
850 // Don't send rendezvous requests to eligible relays.
851 skipHolepunchRendezvous bool
852 // Outgoing connection attempt is in response to holepunch connect message.
853 receivedHolepunchConnect bool
854 HeaderObfuscationPolicy HeaderObfuscationPolicy
857 // Called to dial out and run a connection. The addr we're given is already
858 // considered half-open.
859 func (cl *Client) outgoingConnection(
860 opts outgoingConnOpts,
861 attemptKey outgoingConnAttemptKey,
863 c, err := cl.dialAndCompleteHandshake(opts)
865 c.conn.SetWriteDeadline(time.Time{})
869 // Don't release lock between here and addPeerConn, unless it's for failure.
870 cl.noLongerHalfOpen(opts.t, opts.peerInfo.Addr.String(), attemptKey)
875 "error establishing outgoing connection to %v: %v",
883 c.Discovery = opts.peerInfo.Source
884 c.trusted = opts.peerInfo.Trusted
885 opts.t.runHandshookConnLoggingErr(c)
888 // The port number for incoming peer connections. 0 if the client isn't listening.
889 func (cl *Client) incomingPeerPort() int {
890 return cl.LocalPort()
893 func (cl *Client) initiateHandshakes(c *PeerConn, t *Torrent) error {
894 if c.headerEncrypted {
897 rw, c.cryptoMethod, err = mse.InitiateHandshake(
904 cl.config.CryptoProvides,
908 return fmt.Errorf("header obfuscation handshake: %w", err)
911 ih, err := cl.connBtHandshake(c, &t.infoHash)
913 return fmt.Errorf("bittorrent protocol handshake: %w", err)
915 if ih != t.infoHash {
916 return errors.New("bittorrent protocol handshake: peer infohash didn't match")
921 // Calls f with any secret keys. Note that it takes the Client lock, and so must be used from code
922 // that won't also try to take the lock. This saves us copying all the infohashes everytime.
923 func (cl *Client) forSkeys(f func([]byte) bool) {
926 if false { // Emulate the bug from #114
928 for ih := range cl.torrents {
932 for range cl.torrents {
939 for ih := range cl.torrents {
946 func (cl *Client) handshakeReceiverSecretKeys() mse.SecretKeyIter {
947 if ret := cl.config.Callbacks.ReceiveEncryptedHandshakeSkeys; ret != nil {
953 // Do encryption and bittorrent handshakes as receiver.
954 func (cl *Client) receiveHandshakes(c *PeerConn) (t *Torrent, err error) {
955 defer perf.ScopeTimerErr(&err)()
957 rw, c.headerEncrypted, c.cryptoMethod, err = handleEncryption(c.rw(), cl.handshakeReceiverSecretKeys(), cl.config.HeaderObfuscationPolicy, cl.config.CryptoSelector)
959 if err == nil || err == mse.ErrNoSecretKeyMatch {
960 if c.headerEncrypted {
961 torrent.Add("handshakes received encrypted", 1)
963 torrent.Add("handshakes received unencrypted", 1)
966 torrent.Add("handshakes received with error while handling encryption", 1)
969 if err == mse.ErrNoSecretKeyMatch {
974 if cl.config.HeaderObfuscationPolicy.RequirePreferred && c.headerEncrypted != cl.config.HeaderObfuscationPolicy.Preferred {
975 err = errors.New("connection does not have required header obfuscation")
978 ih, err := cl.connBtHandshake(c, nil)
980 return nil, fmt.Errorf("during bt handshake: %w", err)
988 var successfulPeerWireProtocolHandshakePeerReservedBytes expvar.Map
992 "successful_peer_wire_protocol_handshake_peer_reserved_bytes",
993 &successfulPeerWireProtocolHandshakePeerReservedBytes)
996 func (cl *Client) connBtHandshake(c *PeerConn, ih *metainfo.Hash) (ret metainfo.Hash, err error) {
997 res, err := pp.Handshake(c.rw(), ih, cl.peerID, cl.config.Extensions)
1001 successfulPeerWireProtocolHandshakePeerReservedBytes.Add(
1002 hex.EncodeToString(res.PeerExtensionBits[:]), 1)
1004 c.PeerExtensionBytes = res.PeerExtensionBits
1005 c.PeerID = res.PeerID
1006 c.completedHandshake = time.Now()
1007 if cb := cl.config.Callbacks.CompletedHandshake; cb != nil {
1013 func (cl *Client) runReceivedConn(c *PeerConn) {
1014 err := c.conn.SetDeadline(time.Now().Add(cl.config.HandshakesTimeout))
1018 t, err := cl.receiveHandshakes(c)
1020 cl.logger.LazyLog(log.Debug, func() log.Msg {
1022 "error receiving handshakes on %v: %s", c, err,
1024 "network", c.Network,
1027 torrent.Add("error receiving handshake", 1)
1029 cl.onBadAccept(c.RemoteAddr)
1034 torrent.Add("received handshake for unloaded torrent", 1)
1035 cl.logger.LazyLog(log.Debug, func() log.Msg {
1036 return log.Fmsg("received handshake for unloaded torrent")
1039 cl.onBadAccept(c.RemoteAddr)
1043 torrent.Add("received handshake for loaded torrent", 1)
1044 c.conn.SetWriteDeadline(time.Time{})
1047 t.runHandshookConnLoggingErr(c)
1050 // Client lock must be held before entering this.
1051 func (cl *Client) runHandshookConn(c *PeerConn, t *Torrent) error {
1053 for i, b := range cl.config.MinPeerExtensions {
1054 if c.PeerExtensionBytes[i]&b != b {
1055 return fmt.Errorf("peer did not meet minimum peer extensions: %x", c.PeerExtensionBytes[:])
1058 if c.PeerID == cl.peerID {
1061 addr := c.RemoteAddr.String()
1062 cl.dopplegangerAddrs[addr] = struct{}{}
1064 // Because the remote address is not necessarily the same as its client's torrent listen
1065 // address, we won't record the remote address as a doppleganger. Instead, the initiator
1066 // can record *us* as the doppleganger.
1068 t.logger.Levelf(log.Debug, "local and remote peer ids are the same")
1071 c.r = deadlineReader{c.conn, c.r}
1072 completedHandshakeConnectionFlags.Add(c.connectionFlags(), 1)
1073 if connIsIpv6(c.conn) {
1074 torrent.Add("completed handshake over ipv6", 1)
1076 if err := t.addPeerConn(c); err != nil {
1077 return fmt.Errorf("adding connection: %w", err)
1079 defer t.dropConnection(c)
1080 c.startMessageWriter()
1081 cl.sendInitialMessages(c, t)
1082 c.initUpdateRequestsTimer()
1083 err := c.mainReadLoop()
1085 return fmt.Errorf("main read loop: %w", err)
1090 func (p *Peer) initUpdateRequestsTimer() {
1092 if p.updateRequestsTimer != nil {
1093 panic(p.updateRequestsTimer)
1096 if enableUpdateRequestsTimer {
1097 p.updateRequestsTimer = time.AfterFunc(math.MaxInt64, p.updateRequestsTimerFunc)
1101 const peerUpdateRequestsTimerReason = "updateRequestsTimer"
1103 func (c *Peer) updateRequestsTimerFunc() {
1105 defer c.locker().Unlock()
1106 if c.closed.IsSet() {
1109 if c.isLowOnRequests() {
1110 // If there are no outstanding requests, then a request update should have already run.
1113 if d := time.Since(c.lastRequestUpdate); d < updateRequestsTimerDuration {
1114 // These should be benign, Timer.Stop doesn't guarantee that its function won't run if it's
1115 // already been fired.
1116 torrent.Add("spurious timer requests updates", 1)
1119 c.updateRequests(peerUpdateRequestsTimerReason)
1122 // Maximum pending requests we allow peers to send us. If peer requests are buffered on read, this
1123 // instructs the amount of memory that might be used to cache pending writes. Assuming 512KiB
1124 // (1<<19) cached for sending, for 16KiB (1<<14) chunks.
1125 const localClientReqq = 1024
1127 // See the order given in Transmission's tr_peerMsgsNew.
1128 func (cl *Client) sendInitialMessages(conn *PeerConn, torrent *Torrent) {
1129 if conn.PeerExtensionBytes.SupportsExtended() && cl.config.Extensions.SupportsExtended() {
1130 conn.write(pp.Message{
1132 ExtendedID: pp.HandshakeExtendedID,
1133 ExtendedPayload: func() []byte {
1134 msg := pp.ExtendedHandshakeMessage{
1135 M: map[pp.ExtensionName]pp.ExtensionNumber{
1136 pp.ExtensionNameMetadata: metadataExtendedId,
1137 utHolepunch.ExtensionName: utHolepunchExtendedId,
1139 V: cl.config.ExtendedHandshakeClientVersion,
1140 Reqq: localClientReqq,
1141 YourIp: pp.CompactIp(conn.remoteIp()),
1142 Encryption: cl.config.HeaderObfuscationPolicy.Preferred || !cl.config.HeaderObfuscationPolicy.RequirePreferred,
1143 Port: cl.incomingPeerPort(),
1144 MetadataSize: torrent.metadataSize(),
1145 // TODO: We can figure these out specific to the socket used.
1146 Ipv4: pp.CompactIp(cl.config.PublicIp4.To4()),
1147 Ipv6: cl.config.PublicIp6.To16(),
1149 if !cl.config.DisablePEX {
1150 msg.M[pp.ExtensionNamePex] = pexExtendedId
1152 return bencode.MustMarshal(msg)
1157 if conn.fastEnabled() {
1158 if torrent.haveAllPieces() {
1159 conn.write(pp.Message{Type: pp.HaveAll})
1160 conn.sentHaves.AddRange(0, bitmap.BitRange(conn.t.NumPieces()))
1162 } else if !torrent.haveAnyPieces() {
1163 conn.write(pp.Message{Type: pp.HaveNone})
1164 conn.sentHaves.Clear()
1170 if conn.PeerExtensionBytes.SupportsDHT() && cl.config.Extensions.SupportsDHT() && cl.haveDhtServer() {
1171 conn.write(pp.Message{
1178 func (cl *Client) dhtPort() (ret uint16) {
1179 if len(cl.dhtServers) == 0 {
1182 return uint16(missinggo.AddrPort(cl.dhtServers[len(cl.dhtServers)-1].Addr()))
1185 func (cl *Client) haveDhtServer() bool {
1186 return len(cl.dhtServers) > 0
1189 // Process incoming ut_metadata message.
1190 func (cl *Client) gotMetadataExtensionMsg(payload []byte, t *Torrent, c *PeerConn) error {
1191 var d pp.ExtendedMetadataRequestMsg
1192 err := bencode.Unmarshal(payload, &d)
1193 if _, ok := err.(bencode.ErrUnusedTrailingBytes); ok {
1194 } else if err != nil {
1195 return fmt.Errorf("error unmarshalling bencode: %s", err)
1199 case pp.DataMetadataExtensionMsgType:
1200 c.allStats(add(1, func(cs *ConnStats) *Count { return &cs.MetadataChunksRead }))
1201 if !c.requestedMetadataPiece(piece) {
1202 return fmt.Errorf("got unexpected piece %d", piece)
1204 c.metadataRequests[piece] = false
1205 begin := len(payload) - d.PieceSize()
1206 if begin < 0 || begin >= len(payload) {
1207 return fmt.Errorf("data has bad offset in payload: %d", begin)
1209 t.saveMetadataPiece(piece, payload[begin:])
1210 c.lastUsefulChunkReceived = time.Now()
1211 err = t.maybeCompleteMetadata()
1213 // Log this at the Torrent-level, as we don't partition metadata by Peer yet, so we
1214 // don't know who to blame. TODO: Also errors can be returned here that aren't related
1215 // to verifying metadata, which should be fixed. This should be tagged with metadata, so
1216 // log consumers can filter for this message.
1217 t.logger.WithDefaultLevel(log.Warning).Printf("error completing metadata: %v", err)
1220 case pp.RequestMetadataExtensionMsgType:
1221 if !t.haveMetadataPiece(piece) {
1222 c.write(t.newMetadataExtensionMessage(c, pp.RejectMetadataExtensionMsgType, d.Piece, nil))
1225 start := (1 << 14) * piece
1226 c.logger.WithDefaultLevel(log.Debug).Printf("sending metadata piece %d", piece)
1227 c.write(t.newMetadataExtensionMessage(c, pp.DataMetadataExtensionMsgType, piece, t.metadataBytes[start:start+t.metadataPieceSize(piece)]))
1229 case pp.RejectMetadataExtensionMsgType:
1232 return errors.New("unknown msg_type value")
1236 func (cl *Client) badPeerAddr(addr PeerRemoteAddr) bool {
1237 if ipa, ok := tryIpPortFromNetAddr(addr); ok {
1238 return cl.badPeerIPPort(ipa.IP, ipa.Port)
1243 // Returns whether the IP address and port are considered "bad".
1244 func (cl *Client) badPeerIPPort(ip net.IP, port int) bool {
1245 if port == 0 || ip == nil {
1248 if cl.dopplegangerAddr(net.JoinHostPort(ip.String(), strconv.FormatInt(int64(port), 10))) {
1251 if _, ok := cl.ipBlockRange(ip); ok {
1254 ipAddr, ok := netip.AddrFromSlice(ip)
1258 if _, ok := cl.badPeerIPs[ipAddr]; ok {
1264 // Return a Torrent ready for insertion into a Client.
1265 func (cl *Client) newTorrent(ih metainfo.Hash, specStorage storage.ClientImpl) (t *Torrent) {
1266 return cl.newTorrentOpt(AddTorrentOpts{
1268 Storage: specStorage,
1272 // Return a Torrent ready for insertion into a Client.
1273 func (cl *Client) newTorrentOpt(opts AddTorrentOpts) (t *Torrent) {
1274 // use provided storage, if provided
1275 storageClient := cl.defaultStorage
1276 if opts.Storage != nil {
1277 storageClient = storage.NewClient(opts.Storage)
1282 infoHash: opts.InfoHash,
1283 peers: prioritizedPeers{
1285 getPrio: func(p PeerInfo) peerPriority {
1287 return bep40PriorityIgnoreError(cl.publicAddr(ipPort.IP), ipPort)
1290 conns: make(map[*PeerConn]struct{}, 2*cl.config.EstablishedConnsPerTorrent),
1292 storageOpener: storageClient,
1293 maxEstablishedConns: cl.config.EstablishedConnsPerTorrent,
1295 metadataChanged: sync.Cond{
1298 webSeeds: make(map[string]*Peer),
1299 gotMetainfoC: make(chan struct{}),
1301 t.smartBanCache.Hash = sha1.Sum
1302 t.smartBanCache.Init()
1303 t.networkingEnabled.Set()
1304 t.logger = cl.logger.WithDefaultLevel(log.Debug)
1305 t.sourcesLogger = t.logger.WithNames("sources")
1306 if opts.ChunkSize == 0 {
1307 opts.ChunkSize = defaultChunkSize
1309 t.setChunkSize(opts.ChunkSize)
1313 // A file-like handle to some torrent data resource.
1314 type Handle interface {
1321 func (cl *Client) AddTorrentInfoHash(infoHash metainfo.Hash) (t *Torrent, new bool) {
1322 return cl.AddTorrentInfoHashWithStorage(infoHash, nil)
1325 // Adds a torrent by InfoHash with a custom Storage implementation.
1326 // If the torrent already exists then this Storage is ignored and the
1327 // existing torrent returned with `new` set to `false`
1328 func (cl *Client) AddTorrentInfoHashWithStorage(infoHash metainfo.Hash, specStorage storage.ClientImpl) (t *Torrent, new bool) {
1331 t, ok := cl.torrents[infoHash]
1337 t = cl.newTorrent(infoHash, specStorage)
1338 cl.eachDhtServer(func(s DhtServer) {
1339 if cl.config.PeriodicallyAnnounceTorrentsToDht {
1340 go t.dhtAnnouncer(s)
1343 cl.torrents[infoHash] = t
1344 cl.clearAcceptLimits()
1345 t.updateWantPeersEvent()
1346 // Tickle Client.waitAccept, new torrent may want conns.
1347 cl.event.Broadcast()
1351 // Adds a torrent by InfoHash with a custom Storage implementation. If the torrent already exists
1352 // then this Storage is ignored and the existing torrent returned with `new` set to `false`.
1353 func (cl *Client) AddTorrentOpt(opts AddTorrentOpts) (t *Torrent, new bool) {
1354 infoHash := opts.InfoHash
1357 t, ok := cl.torrents[infoHash]
1363 t = cl.newTorrentOpt(opts)
1364 cl.eachDhtServer(func(s DhtServer) {
1365 if cl.config.PeriodicallyAnnounceTorrentsToDht {
1366 go t.dhtAnnouncer(s)
1369 cl.torrents[infoHash] = t
1370 t.setInfoBytesLocked(opts.InfoBytes)
1371 cl.clearAcceptLimits()
1372 t.updateWantPeersEvent()
1373 // Tickle Client.waitAccept, new torrent may want conns.
1374 cl.event.Broadcast()
1378 type AddTorrentOpts struct {
1380 Storage storage.ClientImpl
1381 ChunkSize pp.Integer
1385 // Add or merge a torrent spec. Returns new if the torrent wasn't already in the client. See also
1386 // Torrent.MergeSpec.
1387 func (cl *Client) AddTorrentSpec(spec *TorrentSpec) (t *Torrent, new bool, err error) {
1388 t, new = cl.AddTorrentOpt(AddTorrentOpts{
1389 InfoHash: spec.InfoHash,
1390 Storage: spec.Storage,
1391 ChunkSize: spec.ChunkSize,
1395 // ChunkSize was already applied by adding a new Torrent, and MergeSpec disallows changing
1397 modSpec.ChunkSize = 0
1399 err = t.MergeSpec(&modSpec)
1400 if err != nil && new {
1406 // The trackers will be merged with the existing ones. If the Info isn't yet known, it will be set.
1407 // spec.DisallowDataDownload/Upload will be read and applied
1408 // The display name is replaced if the new spec provides one. Note that any `Storage` is ignored.
1409 func (t *Torrent) MergeSpec(spec *TorrentSpec) error {
1410 if spec.DisplayName != "" {
1411 t.SetDisplayName(spec.DisplayName)
1413 if spec.InfoBytes != nil {
1414 err := t.SetInfoBytes(spec.InfoBytes)
1420 cl.AddDhtNodes(spec.DhtNodes)
1421 t.UseSources(spec.Sources)
1424 t.initialPieceCheckDisabled = spec.DisableInitialPieceCheck
1425 for _, url := range spec.Webseeds {
1428 for _, peerAddr := range spec.PeerAddrs {
1430 Addr: StringAddr(peerAddr),
1431 Source: PeerSourceDirect,
1435 if spec.ChunkSize != 0 {
1436 panic("chunk size cannot be changed for existing Torrent")
1438 t.addTrackers(spec.Trackers)
1440 t.dataDownloadDisallowed.SetBool(spec.DisallowDataDownload)
1441 t.dataUploadDisallowed = spec.DisallowDataUpload
1445 func (cl *Client) dropTorrent(infoHash metainfo.Hash, wg *sync.WaitGroup) (err error) {
1446 t, ok := cl.torrents[infoHash]
1448 err = fmt.Errorf("no such torrent")
1452 delete(cl.torrents, infoHash)
1456 func (cl *Client) allTorrentsCompleted() bool {
1457 for _, t := range cl.torrents {
1461 if !t.haveAllPieces() {
1468 // Returns true when all torrents are completely downloaded and false if the
1469 // client is stopped before that.
1470 func (cl *Client) WaitAll() bool {
1473 for !cl.allTorrentsCompleted() {
1474 if cl.closed.IsSet() {
1482 // Returns handles to all the torrents loaded in the Client.
1483 func (cl *Client) Torrents() []*Torrent {
1486 return cl.torrentsAsSlice()
1489 func (cl *Client) torrentsAsSlice() (ret []*Torrent) {
1490 for _, t := range cl.torrents {
1491 ret = append(ret, t)
1496 func (cl *Client) AddMagnet(uri string) (T *Torrent, err error) {
1497 spec, err := TorrentSpecFromMagnetUri(uri)
1501 T, _, err = cl.AddTorrentSpec(spec)
1505 func (cl *Client) AddTorrent(mi *metainfo.MetaInfo) (T *Torrent, err error) {
1506 ts, err := TorrentSpecFromMetaInfoErr(mi)
1510 T, _, err = cl.AddTorrentSpec(ts)
1514 func (cl *Client) AddTorrentFromFile(filename string) (T *Torrent, err error) {
1515 mi, err := metainfo.LoadFromFile(filename)
1519 return cl.AddTorrent(mi)
1522 func (cl *Client) DhtServers() []DhtServer {
1523 return cl.dhtServers
1526 func (cl *Client) AddDhtNodes(nodes []string) {
1527 for _, n := range nodes {
1528 hmp := missinggo.SplitHostMaybePort(n)
1529 ip := net.ParseIP(hmp.Host)
1531 cl.logger.Printf("won't add DHT node with bad IP: %q", hmp.Host)
1534 ni := krpc.NodeInfo{
1535 Addr: krpc.NodeAddr{
1540 cl.eachDhtServer(func(s DhtServer) {
1546 func (cl *Client) banPeerIP(ip net.IP) {
1547 // We can't take this from string, because it will lose netip's v4on6. net.ParseIP parses v4
1548 // addresses directly to v4on6, which doesn't compare equal with v4.
1549 ipAddr, ok := netip.AddrFromSlice(ip)
1553 g.MakeMapIfNilAndSet(&cl.badPeerIPs, ipAddr, struct{}{})
1554 for _, t := range cl.torrents {
1555 t.iterPeers(func(p *Peer) {
1556 if p.remoteIp().Equal(ip) {
1557 t.logger.Levelf(log.Warning, "dropping peer %v with banned ip %v", p, ip)
1558 // Should this be a close?
1565 type newConnectionOpts struct {
1567 remoteAddr PeerRemoteAddr
1568 localPublicAddr peerLocalPublicAddr
1573 func (cl *Client) newConnection(nc net.Conn, opts newConnectionOpts) (c *PeerConn) {
1574 if opts.network == "" {
1575 panic(opts.remoteAddr)
1579 outgoing: opts.outgoing,
1582 PeerMaxRequests: 250,
1584 RemoteAddr: opts.remoteAddr,
1585 localPublicAddr: opts.localPublicAddr,
1586 Network: opts.network,
1587 callbacks: &cl.config.Callbacks,
1589 connString: opts.connString,
1592 c.peerRequestDataAllocLimiter.Max = cl.config.MaxAllocPeerRequestDataPerConn
1593 c.initRequestState()
1594 // TODO: Need to be much more explicit about this, including allowing non-IP bannable addresses.
1595 if opts.remoteAddr != nil {
1596 netipAddrPort, err := netip.ParseAddrPort(opts.remoteAddr.String())
1598 c.bannableAddr = Some(netipAddrPort.Addr())
1602 c.logger = cl.logger.WithDefaultLevel(log.Warning)
1603 c.logger = c.logger.WithContextText(fmt.Sprintf("%T %p", c, c))
1604 c.setRW(connStatsReadWriter{nc, c})
1605 c.r = &rateLimitedReader{
1606 l: cl.config.DownloadRateLimiter,
1611 "inited with remoteAddr %v network %v outgoing %t",
1612 opts.remoteAddr, opts.network, opts.outgoing,
1614 for _, f := range cl.config.Callbacks.NewPeer {
1620 func (cl *Client) onDHTAnnouncePeer(ih metainfo.Hash, ip net.IP, port int, portOk bool) {
1627 t.addPeers([]PeerInfo{{
1628 Addr: ipPortAddr{ip, port},
1629 Source: PeerSourceDhtAnnouncePeer,
1633 func firstNotNil(ips ...net.IP) net.IP {
1634 for _, ip := range ips {
1642 func (cl *Client) eachListener(f func(Listener) bool) {
1643 for _, s := range cl.listeners {
1650 func (cl *Client) findListener(f func(Listener) bool) (ret Listener) {
1651 for i := 0; i < len(cl.listeners); i += 1 {
1652 if ret = cl.listeners[i]; f(ret) {
1659 func (cl *Client) publicIp(peer net.IP) net.IP {
1660 // TODO: Use BEP 10 to determine how peers are seeing us.
1661 if peer.To4() != nil {
1663 cl.config.PublicIp4,
1664 cl.findListenerIp(func(ip net.IP) bool { return ip.To4() != nil }),
1669 cl.config.PublicIp6,
1670 cl.findListenerIp(func(ip net.IP) bool { return ip.To4() == nil }),
1674 func (cl *Client) findListenerIp(f func(net.IP) bool) net.IP {
1675 l := cl.findListener(
1676 func(l Listener) bool {
1677 return f(addrIpOrNil(l.Addr()))
1683 return addrIpOrNil(l.Addr())
1686 // Our IP as a peer should see it.
1687 func (cl *Client) publicAddr(peer net.IP) IpPort {
1688 return IpPort{IP: cl.publicIp(peer), Port: uint16(cl.incomingPeerPort())}
1691 // ListenAddrs addresses currently being listened to.
1692 func (cl *Client) ListenAddrs() (ret []net.Addr) {
1694 ret = make([]net.Addr, len(cl.listeners))
1695 for i := 0; i < len(cl.listeners); i += 1 {
1696 ret[i] = cl.listeners[i].Addr()
1702 func (cl *Client) PublicIPs() (ips []net.IP) {
1703 if ip := cl.config.PublicIp4; ip != nil {
1704 ips = append(ips, ip)
1706 if ip := cl.config.PublicIp6; ip != nil {
1707 ips = append(ips, ip)
1712 func (cl *Client) onBadAccept(addr PeerRemoteAddr) {
1713 ipa, ok := tryIpPortFromNetAddr(addr)
1717 ip := maskIpForAcceptLimiting(ipa.IP)
1718 if cl.acceptLimiter == nil {
1719 cl.acceptLimiter = make(map[ipStr]int)
1721 cl.acceptLimiter[ipStr(ip.String())]++
1724 func maskIpForAcceptLimiting(ip net.IP) net.IP {
1725 if ip4 := ip.To4(); ip4 != nil {
1726 return ip4.Mask(net.CIDRMask(24, 32))
1731 func (cl *Client) clearAcceptLimits() {
1732 cl.acceptLimiter = nil
1735 func (cl *Client) acceptLimitClearer() {
1738 case <-cl.closed.Done():
1740 case <-time.After(15 * time.Minute):
1742 cl.clearAcceptLimits()
1748 func (cl *Client) rateLimitAccept(ip net.IP) bool {
1749 if cl.config.DisableAcceptRateLimiting {
1752 return cl.acceptLimiter[ipStr(maskIpForAcceptLimiting(ip).String())] > 0
1755 func (cl *Client) rLock() {
1759 func (cl *Client) rUnlock() {
1763 func (cl *Client) lock() {
1767 func (cl *Client) unlock() {
1771 func (cl *Client) locker() *lockWithDeferreds {
1775 func (cl *Client) String() string {
1776 return fmt.Sprintf("<%[1]T %[1]p>", cl)
1779 // Returns connection-level aggregate connStats at the Client level. See the comment on
1780 // TorrentStats.ConnStats.
1781 func (cl *Client) ConnStats() ConnStats {
1782 return cl.connStats.Copy()
1785 func (cl *Client) Stats() ClientStats {
1788 return cl.statsLocked()