22 "github.com/davecgh/go-spew/spew"
23 "github.com/dustin/go-humanize"
24 gbtree "github.com/google/btree"
25 "github.com/pion/datachannel"
26 "golang.org/x/time/rate"
28 "github.com/anacrolix/chansync"
29 "github.com/anacrolix/chansync/events"
30 "github.com/anacrolix/dht/v2"
31 "github.com/anacrolix/dht/v2/krpc"
32 "github.com/anacrolix/generics"
33 . "github.com/anacrolix/generics"
34 "github.com/anacrolix/log"
35 "github.com/anacrolix/missinggo/perf"
36 "github.com/anacrolix/missinggo/v2"
37 "github.com/anacrolix/missinggo/v2/bitmap"
38 "github.com/anacrolix/missinggo/v2/pproffd"
39 "github.com/anacrolix/sync"
41 "github.com/anacrolix/torrent/bencode"
42 "github.com/anacrolix/torrent/internal/limiter"
43 "github.com/anacrolix/torrent/iplist"
44 "github.com/anacrolix/torrent/metainfo"
45 "github.com/anacrolix/torrent/mse"
46 pp "github.com/anacrolix/torrent/peer_protocol"
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/webtorrent"
53 // Clients contain zero or more Torrents. A Client manages a blocklist, the
54 // TCP/UDP protocol ports, and DHT as desired.
56 // An aggregate of stats over all connections. First in struct to ensure 64-bit alignment of
62 closed chansync.SetOnce
68 defaultStorage *storage.Client
72 dhtServers []DhtServer
73 ipBlockList iplist.Ranger
75 // Set of addresses that have our client ID. This intentionally will
76 // include ourselves if we end up trying to connect to our own address
77 // through legitimate channels.
78 dopplegangerAddrs map[string]struct{}
79 badPeerIPs map[netip.Addr]struct{}
80 torrents map[InfoHash]*Torrent
81 pieceRequestOrder map[interface{}]*request_strategy.PieceRequestOrder
83 acceptLimiter map[ipStr]int
84 dialRateLimiter *rate.Limiter
87 websocketTrackers websocketTrackers
89 activeAnnounceLimiter limiter.Instance
90 httpClient *http.Client
95 func (cl *Client) BadPeerIPs() (ips []string) {
97 ips = cl.badPeerIPsLocked()
102 func (cl *Client) badPeerIPsLocked() (ips []string) {
103 ips = make([]string, len(cl.badPeerIPs))
105 for k := range cl.badPeerIPs {
112 func (cl *Client) PeerID() PeerID {
116 // Returns the port number for the first listener that has one. No longer assumes that all port
117 // numbers are the same, due to support for custom listeners. Returns zero if no port number is
119 func (cl *Client) LocalPort() (port int) {
120 for i := 0; i < len(cl.listeners); i += 1 {
121 if port = addrPortOrZero(cl.listeners[i].Addr()); port != 0 {
128 func writeDhtServerStatus(w io.Writer, s DhtServer) {
129 dhtStats := s.Stats()
130 fmt.Fprintf(w, " ID: %x\n", s.ID())
131 spew.Fdump(w, dhtStats)
134 // Writes out a human readable status of the client, such as for writing to a
136 func (cl *Client) WriteStatus(_w io.Writer) {
139 w := bufio.NewWriter(_w)
141 fmt.Fprintf(w, "Listen port: %d\n", cl.LocalPort())
142 fmt.Fprintf(w, "Peer ID: %+q\n", cl.PeerID())
143 fmt.Fprintf(w, "Extension bits: %v\n", cl.config.Extensions)
144 fmt.Fprintf(w, "Announce key: %x\n", cl.announceKey())
145 fmt.Fprintf(w, "Banned IPs: %d\n", len(cl.badPeerIPsLocked()))
146 cl.eachDhtServer(func(s DhtServer) {
147 fmt.Fprintf(w, "%s DHT server at %s:\n", s.Addr().Network(), s.Addr().String())
148 writeDhtServerStatus(w, s)
150 spew.Fdump(w, &cl.stats)
151 torrentsSlice := cl.torrentsAsSlice()
152 fmt.Fprintf(w, "# Torrents: %d\n", len(torrentsSlice))
154 sort.Slice(torrentsSlice, func(l, r int) bool {
155 return torrentsSlice[l].infoHash.AsString() < torrentsSlice[r].infoHash.AsString()
157 for _, t := range torrentsSlice {
159 fmt.Fprint(w, "<unknown name>")
161 fmt.Fprint(w, t.name())
167 "%f%% of %d bytes (%s)",
168 100*(1-float64(t.bytesMissingLocked())/float64(t.info.TotalLength())),
170 humanize.Bytes(uint64(t.length())))
172 w.WriteString("<missing metainfo>")
180 func (cl *Client) initLogger() {
181 logger := cl.config.Logger
186 logger = logger.FilterLevel(log.Debug)
188 cl.logger = logger.WithValues(cl)
191 func (cl *Client) announceKey() int32 {
192 return int32(binary.BigEndian.Uint32(cl.peerID[16:20]))
195 // Initializes a bare minimum Client. *Client and *ClientConfig must not be nil.
196 func (cl *Client) init(cfg *ClientConfig) {
198 generics.MakeMap(&cl.dopplegangerAddrs)
199 cl.torrents = make(map[metainfo.Hash]*Torrent)
200 cl.dialRateLimiter = rate.NewLimiter(10, 10)
201 cl.activeAnnounceLimiter.SlotsPerKey = 2
202 cl.event.L = cl.locker()
203 cl.ipBlockList = cfg.IPBlocklist
204 cl.httpClient = &http.Client{
205 Transport: &http.Transport{
206 Proxy: cfg.HTTPProxy,
207 // I think this value was observed from some webseeds. It seems reasonable to extend it
208 // to other uses of HTTP from the client.
214 func NewClient(cfg *ClientConfig) (cl *Client, err error) {
216 cfg = NewDefaultClientConfig()
222 go cl.acceptLimitClearer()
231 storageImpl := cfg.DefaultStorage
232 if storageImpl == nil {
233 // We'd use mmap by default but HFS+ doesn't support sparse files.
234 storageImplCloser := storage.NewFile(cfg.DataDir)
235 cl.onClose = append(cl.onClose, func() {
236 if err := storageImplCloser.Close(); err != nil {
237 cl.logger.Printf("error closing default storage: %s", err)
240 storageImpl = storageImplCloser
242 cl.defaultStorage = storage.NewClient(storageImpl)
244 if cfg.PeerID != "" {
245 missinggo.CopyExact(&cl.peerID, cfg.PeerID)
247 o := copy(cl.peerID[:], cfg.Bep20)
248 _, err = rand.Read(cl.peerID[o:])
250 panic("error generating peer id")
254 sockets, err := listenAll(cl.listenNetworks(), cl.config.ListenHost, cl.config.ListenPort, cl.firewallCallback, cl.logger)
262 for _, _s := range sockets {
263 s := _s // Go is fucking retarded.
264 cl.onClose = append(cl.onClose, func() { go s.Close() })
265 if peerNetworkEnabled(parseNetworkString(s.Addr().Network()), cl.config) {
266 cl.dialers = append(cl.dialers, s)
267 cl.listeners = append(cl.listeners, s)
268 if cl.config.AcceptPeerConnections {
269 go cl.acceptConnections(s)
276 for _, s := range sockets {
277 if pc, ok := s.(net.PacketConn); ok {
278 ds, err := cl.NewAnacrolixDhtServer(pc)
282 cl.dhtServers = append(cl.dhtServers, AnacrolixDhtServerWrapper{ds})
283 cl.onClose = append(cl.onClose, func() { ds.Close() })
288 cl.websocketTrackers = websocketTrackers{
291 GetAnnounceRequest: func(event tracker.AnnounceEvent, infoHash [20]byte) (tracker.AnnounceRequest, error) {
294 t, ok := cl.torrents[infoHash]
296 return tracker.AnnounceRequest{}, errors.New("torrent not tracked by client")
298 return t.announceRequest(event), nil
300 Proxy: cl.config.HTTPProxy,
301 OnConn: func(dc datachannel.ReadWriteCloser, dcc webtorrent.DataChannelContext) {
304 t, ok := cl.torrents[dcc.InfoHash]
306 cl.logger.WithDefaultLevel(log.Warning).Printf(
307 "got webrtc conn for unloaded torrent with infohash %x",
313 go t.onWebRtcConn(dc, dcc)
320 func (cl *Client) AddDhtServer(d DhtServer) {
321 cl.dhtServers = append(cl.dhtServers, d)
324 // Adds a Dialer for outgoing connections. All Dialers are used when attempting to connect to a
325 // given address for any Torrent.
326 func (cl *Client) AddDialer(d Dialer) {
329 cl.dialers = append(cl.dialers, d)
330 for _, t := range cl.torrents {
335 func (cl *Client) Listeners() []Listener {
339 // Registers a Listener, and starts Accepting on it. You must Close Listeners provided this way
341 func (cl *Client) AddListener(l Listener) {
342 cl.listeners = append(cl.listeners, l)
343 if cl.config.AcceptPeerConnections {
344 go cl.acceptConnections(l)
348 func (cl *Client) firewallCallback(net.Addr) bool {
350 block := !cl.wantConns() || !cl.config.AcceptPeerConnections
353 torrent.Add("connections firewalled", 1)
355 torrent.Add("connections not firewalled", 1)
360 func (cl *Client) listenOnNetwork(n network) bool {
361 if n.Ipv4 && cl.config.DisableIPv4 {
364 if n.Ipv6 && cl.config.DisableIPv6 {
367 if n.Tcp && cl.config.DisableTCP {
370 if n.Udp && cl.config.DisableUTP && cl.config.NoDHT {
376 func (cl *Client) listenNetworks() (ns []network) {
377 for _, n := range allPeerNetworks {
378 if cl.listenOnNetwork(n) {
385 // Creates an anacrolix/dht Server, as would be done internally in NewClient, for the given conn.
386 func (cl *Client) NewAnacrolixDhtServer(conn net.PacketConn) (s *dht.Server, err error) {
387 logger := cl.logger.WithNames("dht", conn.LocalAddr().String())
388 cfg := dht.ServerConfig{
389 IPBlocklist: cl.ipBlockList,
391 OnAnnouncePeer: cl.onDHTAnnouncePeer,
392 PublicIP: func() net.IP {
393 if connIsIpv6(conn) && cl.config.PublicIp6 != nil {
394 return cl.config.PublicIp6
396 return cl.config.PublicIp4
398 StartingNodes: cl.config.DhtStartingNodes(conn.LocalAddr().Network()),
399 OnQuery: cl.config.DHTOnQuery,
402 if f := cl.config.ConfigureAnacrolixDhtServer; f != nil {
405 s, err = dht.NewServer(&cfg)
408 ts, err := s.Bootstrap()
410 logger.Levelf(log.Warning, "error bootstrapping dht: %s", err)
412 logger.Levelf(log.Debug, "completed bootstrap: %+v", ts)
418 func (cl *Client) Closed() events.Done {
419 return cl.closed.Done()
422 func (cl *Client) eachDhtServer(f func(DhtServer)) {
423 for _, ds := range cl.dhtServers {
428 // Stops the client. All connections to peers are closed and all activity will come to a halt.
429 func (cl *Client) Close() (errs []error) {
430 var closeGroup sync.WaitGroup // For concurrent cleanup to complete before returning
432 for _, t := range cl.torrents {
433 err := t.close(&closeGroup)
435 errs = append(errs, err)
438 for i := range cl.onClose {
439 cl.onClose[len(cl.onClose)-1-i]()
444 closeGroup.Wait() // defer is LIFO. We want to Wait() after cl.unlock()
448 func (cl *Client) ipBlockRange(ip net.IP) (r iplist.Range, blocked bool) {
449 if cl.ipBlockList == nil {
452 return cl.ipBlockList.Lookup(ip)
455 func (cl *Client) ipIsBlocked(ip net.IP) bool {
456 _, blocked := cl.ipBlockRange(ip)
460 func (cl *Client) wantConns() bool {
461 if cl.config.AlwaysWantConns {
464 for _, t := range cl.torrents {
472 // TODO: Apply filters for non-standard networks, particularly rate-limiting.
473 func (cl *Client) rejectAccepted(conn net.Conn) error {
475 return errors.New("don't want conns right now")
477 ra := conn.RemoteAddr()
478 if rip := addrIpOrNil(ra); rip != nil {
479 if cl.config.DisableIPv4Peers && rip.To4() != nil {
480 return errors.New("ipv4 peers disabled")
482 if cl.config.DisableIPv4 && len(rip) == net.IPv4len {
483 return errors.New("ipv4 disabled")
485 if cl.config.DisableIPv6 && len(rip) == net.IPv6len && rip.To4() == nil {
486 return errors.New("ipv6 disabled")
488 if cl.rateLimitAccept(rip) {
489 return errors.New("source IP accepted rate limited")
491 if cl.badPeerIPPort(rip, missinggo.AddrPort(ra)) {
492 return errors.New("bad source addr")
498 func (cl *Client) acceptConnections(l Listener) {
500 conn, err := l.Accept()
501 torrent.Add("client listener accepts", 1)
502 conn = pproffd.WrapNetConn(conn)
504 closed := cl.closed.IsSet()
506 if !closed && conn != nil {
507 reject = cl.rejectAccepted(conn)
517 log.Fmsg("error accepting connection: %s", err).LogLevel(log.Debug, cl.logger)
522 torrent.Add("rejected accepted connections", 1)
523 cl.logger.LazyLog(log.Debug, func() log.Msg {
524 return log.Fmsg("rejecting accepted conn: %v", reject)
528 go cl.incomingConnection(conn)
530 cl.logger.LazyLog(log.Debug, func() log.Msg {
531 return log.Fmsg("accepted %q connection at %q from %q",
537 torrent.Add(fmt.Sprintf("accepted conn remote IP len=%d", len(addrIpOrNil(conn.RemoteAddr()))), 1)
538 torrent.Add(fmt.Sprintf("accepted conn network=%s", conn.RemoteAddr().Network()), 1)
539 torrent.Add(fmt.Sprintf("accepted on %s listener", l.Addr().Network()), 1)
544 // Creates the PeerConn.connString for a regular net.Conn PeerConn.
545 func regularNetConnPeerConnConnString(nc net.Conn) string {
546 return fmt.Sprintf("%s-%s", nc.LocalAddr(), nc.RemoteAddr())
549 func (cl *Client) incomingConnection(nc net.Conn) {
551 if tc, ok := nc.(*net.TCPConn); ok {
554 remoteAddr, _ := tryIpPortFromNetAddr(nc.RemoteAddr())
555 c := cl.newConnection(
559 remoteAddr: nc.RemoteAddr(),
560 localPublicAddr: cl.publicAddr(remoteAddr.IP),
561 network: nc.RemoteAddr().Network(),
562 connString: regularNetConnPeerConnConnString(nc),
569 c.Discovery = PeerSourceIncoming
570 cl.runReceivedConn(c)
573 // Returns a handle to the given torrent, if it's present in the client.
574 func (cl *Client) Torrent(ih metainfo.Hash) (t *Torrent, ok bool) {
577 t, ok = cl.torrents[ih]
581 func (cl *Client) torrent(ih metainfo.Hash) *Torrent {
582 return cl.torrents[ih]
585 type DialResult struct {
590 func countDialResult(err error) {
592 torrent.Add("successful dials", 1)
594 torrent.Add("unsuccessful dials", 1)
598 func reducedDialTimeout(minDialTimeout, max time.Duration, halfOpenLimit, pendingPeers int) (ret time.Duration) {
599 ret = max / time.Duration((pendingPeers+halfOpenLimit)/halfOpenLimit)
600 if ret < minDialTimeout {
606 // Returns whether an address is known to connect to a client with our own ID.
607 func (cl *Client) dopplegangerAddr(addr string) bool {
608 _, ok := cl.dopplegangerAddrs[addr]
612 // Returns a connection over UTP or TCP, whichever is first to connect.
613 func (cl *Client) dialFirst(ctx context.Context, addr string) (res DialResult) {
614 return DialFirst(ctx, addr, cl.dialers)
617 // Returns a connection over UTP or TCP, whichever is first to connect.
618 func DialFirst(ctx context.Context, addr string, dialers []Dialer) (res DialResult) {
620 t := perf.NewTimer(perf.CallerName(0))
623 t.Mark(fmt.Sprintf("returned no conn (context: %v)", ctx.Err()))
625 t.Mark("returned conn over " + res.Dialer.DialerNetwork())
629 ctx, cancel := context.WithCancel(ctx)
630 // As soon as we return one connection, cancel the others.
633 resCh := make(chan DialResult, left)
634 for _, _s := range dialers {
639 dialFromSocket(ctx, s, addr),
644 // Wait for a successful connection.
646 defer perf.ScopeTimer()()
647 for ; left > 0 && res.Conn == nil; left-- {
651 // There are still incompleted dials.
653 for ; left > 0; left-- {
654 conn := (<-resCh).Conn
661 go torrent.Add(fmt.Sprintf("network dialed first: %s", res.Conn.RemoteAddr().Network()), 1)
666 func dialFromSocket(ctx context.Context, s Dialer, addr string) net.Conn {
667 c, err := s.Dial(ctx, addr)
668 // This is a bit optimistic, but it looks non-trivial to thread this through the proxy code. Set
669 // it now in case we close the connection forthwith.
670 if tc, ok := c.(*net.TCPConn); ok {
677 func forgettableDialError(err error) bool {
678 return strings.Contains(err.Error(), "no suitable address found")
681 func (cl *Client) noLongerHalfOpen(t *Torrent, addr string) {
682 if _, ok := t.halfOpen[addr]; !ok {
683 panic("invariant broken")
685 delete(t.halfOpen, addr)
687 for _, t := range cl.torrents {
692 // Performs initiator handshakes and returns a connection. Returns nil *connection if no connection
693 // for valid reasons.
694 func (cl *Client) initiateProtocolHandshakes(
699 newConnOpts newConnectionOpts,
701 c *PeerConn, err error,
703 c = cl.newConnection(nc, newConnOpts)
704 c.headerEncrypted = encryptHeader
705 ctx, cancel := context.WithTimeout(ctx, cl.config.HandshakesTimeout)
707 dl, ok := ctx.Deadline()
711 err = nc.SetDeadline(dl)
715 err = cl.initiateHandshakes(c, t)
719 // Returns nil connection and nil error if no connection could be established for valid reasons.
720 func (cl *Client) establishOutgoingConnEx(t *Torrent, addr PeerRemoteAddr, obfuscatedHeader bool) (*PeerConn, error) {
721 dialCtx, cancel := context.WithTimeout(context.Background(), func() time.Duration {
724 return t.dialTimeout()
727 dr := cl.dialFirst(dialCtx, addr.String())
730 if dialCtx.Err() != nil {
731 return nil, fmt.Errorf("dialing: %w", dialCtx.Err())
733 return nil, errors.New("dial failed")
735 addrIpPort, _ := tryIpPortFromNetAddr(addr)
736 c, err := cl.initiateProtocolHandshakes(context.Background(), nc, t, obfuscatedHeader, newConnectionOpts{
739 // It would be possible to retrieve a public IP from the dialer used here?
740 localPublicAddr: cl.publicAddr(addrIpPort.IP),
741 network: dr.Dialer.DialerNetwork(),
742 connString: regularNetConnPeerConnConnString(nc),
750 // Returns nil connection and nil error if no connection could be established
751 // for valid reasons.
752 func (cl *Client) establishOutgoingConn(t *Torrent, addr PeerRemoteAddr) (c *PeerConn, err error) {
753 torrent.Add("establish outgoing connection", 1)
754 obfuscatedHeaderFirst := cl.config.HeaderObfuscationPolicy.Preferred
755 c, err = cl.establishOutgoingConnEx(t, addr, obfuscatedHeaderFirst)
757 torrent.Add("initiated conn with preferred header obfuscation", 1)
760 // cl.logger.Printf("error establishing connection to %s (obfuscatedHeader=%t): %v", addr, obfuscatedHeaderFirst, err)
761 if cl.config.HeaderObfuscationPolicy.RequirePreferred {
762 // We should have just tried with the preferred header obfuscation. If it was required,
763 // there's nothing else to try.
766 // Try again with encryption if we didn't earlier, or without if we did.
767 c, err = cl.establishOutgoingConnEx(t, addr, !obfuscatedHeaderFirst)
769 torrent.Add("initiated conn with fallback header obfuscation", 1)
771 // cl.logger.Printf("error establishing fallback connection to %v: %v", addr, err)
775 // Called to dial out and run a connection. The addr we're given is already
776 // considered half-open.
777 func (cl *Client) outgoingConnection(t *Torrent, addr PeerRemoteAddr, ps PeerSource, trusted bool) {
778 cl.dialRateLimiter.Wait(context.Background())
779 c, err := cl.establishOutgoingConn(t, addr)
781 c.conn.SetWriteDeadline(time.Time{})
785 // Don't release lock between here and addPeerConn, unless it's for
787 cl.noLongerHalfOpen(t, addr.String())
790 cl.logger.Levelf(log.Debug, "error establishing outgoing connection to %v: %v", addr, err)
797 t.runHandshookConnLoggingErr(c)
800 // The port number for incoming peer connections. 0 if the client isn't listening.
801 func (cl *Client) incomingPeerPort() int {
802 return cl.LocalPort()
805 func (cl *Client) initiateHandshakes(c *PeerConn, t *Torrent) error {
806 if c.headerEncrypted {
809 rw, c.cryptoMethod, err = mse.InitiateHandshake(
816 cl.config.CryptoProvides,
820 return fmt.Errorf("header obfuscation handshake: %w", err)
823 ih, err := cl.connBtHandshake(c, &t.infoHash)
825 return fmt.Errorf("bittorrent protocol handshake: %w", err)
827 if ih != t.infoHash {
828 return errors.New("bittorrent protocol handshake: peer infohash didn't match")
833 // Calls f with any secret keys. Note that it takes the Client lock, and so must be used from code
834 // that won't also try to take the lock. This saves us copying all the infohashes everytime.
835 func (cl *Client) forSkeys(f func([]byte) bool) {
838 if false { // Emulate the bug from #114
840 for ih := range cl.torrents {
844 for range cl.torrents {
851 for ih := range cl.torrents {
858 func (cl *Client) handshakeReceiverSecretKeys() mse.SecretKeyIter {
859 if ret := cl.config.Callbacks.ReceiveEncryptedHandshakeSkeys; ret != nil {
865 // Do encryption and bittorrent handshakes as receiver.
866 func (cl *Client) receiveHandshakes(c *PeerConn) (t *Torrent, err error) {
867 defer perf.ScopeTimerErr(&err)()
869 rw, c.headerEncrypted, c.cryptoMethod, err = handleEncryption(c.rw(), cl.handshakeReceiverSecretKeys(), cl.config.HeaderObfuscationPolicy, cl.config.CryptoSelector)
871 if err == nil || err == mse.ErrNoSecretKeyMatch {
872 if c.headerEncrypted {
873 torrent.Add("handshakes received encrypted", 1)
875 torrent.Add("handshakes received unencrypted", 1)
878 torrent.Add("handshakes received with error while handling encryption", 1)
881 if err == mse.ErrNoSecretKeyMatch {
886 if cl.config.HeaderObfuscationPolicy.RequirePreferred && c.headerEncrypted != cl.config.HeaderObfuscationPolicy.Preferred {
887 err = errors.New("connection does not have required header obfuscation")
890 ih, err := cl.connBtHandshake(c, nil)
892 return nil, fmt.Errorf("during bt handshake: %w", err)
900 var successfulPeerWireProtocolHandshakePeerReservedBytes expvar.Map
904 "successful_peer_wire_protocol_handshake_peer_reserved_bytes",
905 &successfulPeerWireProtocolHandshakePeerReservedBytes)
908 func (cl *Client) connBtHandshake(c *PeerConn, ih *metainfo.Hash) (ret metainfo.Hash, err error) {
909 res, err := pp.Handshake(c.rw(), ih, cl.peerID, cl.config.Extensions)
913 successfulPeerWireProtocolHandshakePeerReservedBytes.Add(res.PeerExtensionBits.String(), 1)
915 c.PeerExtensionBytes = res.PeerExtensionBits
916 c.PeerID = res.PeerID
917 c.completedHandshake = time.Now()
918 if cb := cl.config.Callbacks.CompletedHandshake; cb != nil {
924 func (cl *Client) runReceivedConn(c *PeerConn) {
925 err := c.conn.SetDeadline(time.Now().Add(cl.config.HandshakesTimeout))
929 t, err := cl.receiveHandshakes(c)
931 cl.logger.LazyLog(log.Debug, func() log.Msg {
933 "error receiving handshakes on %v: %s", c, err,
935 "network", c.Network,
938 torrent.Add("error receiving handshake", 1)
940 cl.onBadAccept(c.RemoteAddr)
945 torrent.Add("received handshake for unloaded torrent", 1)
946 cl.logger.LazyLog(log.Debug, func() log.Msg {
947 return log.Fmsg("received handshake for unloaded torrent")
950 cl.onBadAccept(c.RemoteAddr)
954 torrent.Add("received handshake for loaded torrent", 1)
955 c.conn.SetWriteDeadline(time.Time{})
958 t.runHandshookConnLoggingErr(c)
961 // Client lock must be held before entering this.
962 func (cl *Client) runHandshookConn(c *PeerConn, t *Torrent) error {
964 for i, b := range cl.config.MinPeerExtensions {
965 if c.PeerExtensionBytes[i]&b != b {
966 return fmt.Errorf("peer did not meet minimum peer extensions: %x", c.PeerExtensionBytes[:])
969 if c.PeerID == cl.peerID {
972 addr := c.RemoteAddr.String()
973 cl.dopplegangerAddrs[addr] = struct{}{}
975 // Because the remote address is not necessarily the same as its client's torrent listen
976 // address, we won't record the remote address as a doppleganger. Instead, the initiator
977 // can record *us* as the doppleganger.
979 t.logger.Levelf(log.Debug, "local and remote peer ids are the same")
982 c.r = deadlineReader{c.conn, c.r}
983 completedHandshakeConnectionFlags.Add(c.connectionFlags(), 1)
984 if connIsIpv6(c.conn) {
985 torrent.Add("completed handshake over ipv6", 1)
987 if err := t.addPeerConn(c); err != nil {
988 return fmt.Errorf("adding connection: %w", err)
990 defer t.dropConnection(c)
991 c.startMessageWriter()
992 cl.sendInitialMessages(c, t)
993 c.initUpdateRequestsTimer()
994 err := c.mainReadLoop()
996 return fmt.Errorf("main read loop: %w", err)
1003 func (p *Peer) initUpdateRequestsTimer() {
1005 if p.updateRequestsTimer != nil {
1006 panic(p.updateRequestsTimer)
1009 if enableUpdateRequestsTimer {
1010 p.updateRequestsTimer = time.AfterFunc(math.MaxInt64, p.updateRequestsTimerFunc)
1014 const peerUpdateRequestsTimerReason = "updateRequestsTimer"
1016 func (c *Peer) updateRequestsTimerFunc() {
1018 defer c.locker().Unlock()
1019 if c.closed.IsSet() {
1022 if c.isLowOnRequests() {
1023 // If there are no outstanding requests, then a request update should have already run.
1026 if d := time.Since(c.lastRequestUpdate); d < updateRequestsTimerDuration {
1027 // These should be benign, Timer.Stop doesn't guarantee that its function won't run if it's
1028 // already been fired.
1029 torrent.Add("spurious timer requests updates", 1)
1032 c.updateRequests(peerUpdateRequestsTimerReason)
1035 // Maximum pending requests we allow peers to send us. If peer requests are buffered on read, this
1036 // instructs the amount of memory that might be used to cache pending writes. Assuming 512KiB
1037 // (1<<19) cached for sending, for 16KiB (1<<14) chunks.
1038 const localClientReqq = 1024
1040 // See the order given in Transmission's tr_peerMsgsNew.
1041 func (cl *Client) sendInitialMessages(conn *PeerConn, torrent *Torrent) {
1042 if conn.PeerExtensionBytes.SupportsExtended() && cl.config.Extensions.SupportsExtended() {
1043 conn.write(pp.Message{
1045 ExtendedID: pp.HandshakeExtendedID,
1046 ExtendedPayload: func() []byte {
1047 msg := pp.ExtendedHandshakeMessage{
1048 M: map[pp.ExtensionName]pp.ExtensionNumber{
1049 pp.ExtensionNameMetadata: metadataExtendedId,
1051 V: cl.config.ExtendedHandshakeClientVersion,
1052 Reqq: localClientReqq,
1053 YourIp: pp.CompactIp(conn.remoteIp()),
1054 Encryption: cl.config.HeaderObfuscationPolicy.Preferred || !cl.config.HeaderObfuscationPolicy.RequirePreferred,
1055 Port: cl.incomingPeerPort(),
1056 MetadataSize: torrent.metadataSize(),
1057 // TODO: We can figured these out specific to the socket
1059 Ipv4: pp.CompactIp(cl.config.PublicIp4.To4()),
1060 Ipv6: cl.config.PublicIp6.To16(),
1062 if !cl.config.DisablePEX {
1063 msg.M[pp.ExtensionNamePex] = pexExtendedId
1065 return bencode.MustMarshal(msg)
1070 if conn.fastEnabled() {
1071 if torrent.haveAllPieces() {
1072 conn.write(pp.Message{Type: pp.HaveAll})
1073 conn.sentHaves.AddRange(0, bitmap.BitRange(conn.t.NumPieces()))
1075 } else if !torrent.haveAnyPieces() {
1076 conn.write(pp.Message{Type: pp.HaveNone})
1077 conn.sentHaves.Clear()
1083 if conn.PeerExtensionBytes.SupportsDHT() && cl.config.Extensions.SupportsDHT() && cl.haveDhtServer() {
1084 conn.write(pp.Message{
1091 func (cl *Client) dhtPort() (ret uint16) {
1092 if len(cl.dhtServers) == 0 {
1095 return uint16(missinggo.AddrPort(cl.dhtServers[len(cl.dhtServers)-1].Addr()))
1098 func (cl *Client) haveDhtServer() bool {
1099 return len(cl.dhtServers) > 0
1102 // Process incoming ut_metadata message.
1103 func (cl *Client) gotMetadataExtensionMsg(payload []byte, t *Torrent, c *PeerConn) error {
1104 var d pp.ExtendedMetadataRequestMsg
1105 err := bencode.Unmarshal(payload, &d)
1106 if _, ok := err.(bencode.ErrUnusedTrailingBytes); ok {
1107 } else if err != nil {
1108 return fmt.Errorf("error unmarshalling bencode: %s", err)
1112 case pp.DataMetadataExtensionMsgType:
1113 c.allStats(add(1, func(cs *ConnStats) *Count { return &cs.MetadataChunksRead }))
1114 if !c.requestedMetadataPiece(piece) {
1115 return fmt.Errorf("got unexpected piece %d", piece)
1117 c.metadataRequests[piece] = false
1118 begin := len(payload) - d.PieceSize()
1119 if begin < 0 || begin >= len(payload) {
1120 return fmt.Errorf("data has bad offset in payload: %d", begin)
1122 t.saveMetadataPiece(piece, payload[begin:])
1123 c.lastUsefulChunkReceived = time.Now()
1124 err = t.maybeCompleteMetadata()
1126 // Log this at the Torrent-level, as we don't partition metadata by Peer yet, so we
1127 // don't know who to blame. TODO: Also errors can be returned here that aren't related
1128 // to verifying metadata, which should be fixed. This should be tagged with metadata, so
1129 // log consumers can filter for this message.
1130 t.logger.WithDefaultLevel(log.Warning).Printf("error completing metadata: %v", err)
1133 case pp.RequestMetadataExtensionMsgType:
1134 if !t.haveMetadataPiece(piece) {
1135 c.write(t.newMetadataExtensionMessage(c, pp.RejectMetadataExtensionMsgType, d.Piece, nil))
1138 start := (1 << 14) * piece
1139 c.logger.WithDefaultLevel(log.Debug).Printf("sending metadata piece %d", piece)
1140 c.write(t.newMetadataExtensionMessage(c, pp.DataMetadataExtensionMsgType, piece, t.metadataBytes[start:start+t.metadataPieceSize(piece)]))
1142 case pp.RejectMetadataExtensionMsgType:
1145 return errors.New("unknown msg_type value")
1149 func (cl *Client) badPeerAddr(addr PeerRemoteAddr) bool {
1150 if ipa, ok := tryIpPortFromNetAddr(addr); ok {
1151 return cl.badPeerIPPort(ipa.IP, ipa.Port)
1156 // Returns whether the IP address and port are considered "bad".
1157 func (cl *Client) badPeerIPPort(ip net.IP, port int) bool {
1158 if port == 0 || ip == nil {
1161 if cl.dopplegangerAddr(net.JoinHostPort(ip.String(), strconv.FormatInt(int64(port), 10))) {
1164 if _, ok := cl.ipBlockRange(ip); ok {
1167 ipAddr, ok := netip.AddrFromSlice(ip)
1171 if _, ok := cl.badPeerIPs[ipAddr]; ok {
1177 // Return a Torrent ready for insertion into a Client.
1178 func (cl *Client) newTorrent(ih metainfo.Hash, specStorage storage.ClientImpl) (t *Torrent) {
1179 return cl.newTorrentOpt(AddTorrentOpts{
1181 Storage: specStorage,
1185 // Return a Torrent ready for insertion into a Client.
1186 func (cl *Client) newTorrentOpt(opts AddTorrentOpts) (t *Torrent) {
1187 // use provided storage, if provided
1188 storageClient := cl.defaultStorage
1189 if opts.Storage != nil {
1190 storageClient = storage.NewClient(opts.Storage)
1195 infoHash: opts.InfoHash,
1196 peers: prioritizedPeers{
1198 getPrio: func(p PeerInfo) peerPriority {
1200 return bep40PriorityIgnoreError(cl.publicAddr(ipPort.IP), ipPort)
1203 conns: make(map[*PeerConn]struct{}, 2*cl.config.EstablishedConnsPerTorrent),
1205 halfOpen: make(map[string]PeerInfo),
1207 storageOpener: storageClient,
1208 maxEstablishedConns: cl.config.EstablishedConnsPerTorrent,
1210 metadataChanged: sync.Cond{
1213 webSeeds: make(map[string]*Peer),
1214 gotMetainfoC: make(chan struct{}),
1216 t.smartBanCache.Hash = sha1.Sum
1217 t.smartBanCache.Init()
1218 t.networkingEnabled.Set()
1219 t.logger = cl.logger.WithContextValue(t).WithNames("torrent", t.infoHash.HexString())
1220 t.sourcesLogger = t.logger.WithNames("sources")
1221 if opts.ChunkSize == 0 {
1222 opts.ChunkSize = defaultChunkSize
1224 t.setChunkSize(opts.ChunkSize)
1228 // A file-like handle to some torrent data resource.
1229 type Handle interface {
1236 func (cl *Client) AddTorrentInfoHash(infoHash metainfo.Hash) (t *Torrent, new bool) {
1237 return cl.AddTorrentInfoHashWithStorage(infoHash, nil)
1240 // Adds a torrent by InfoHash with a custom Storage implementation.
1241 // If the torrent already exists then this Storage is ignored and the
1242 // existing torrent returned with `new` set to `false`
1243 func (cl *Client) AddTorrentInfoHashWithStorage(infoHash metainfo.Hash, specStorage storage.ClientImpl) (t *Torrent, new bool) {
1246 t, ok := cl.torrents[infoHash]
1252 t = cl.newTorrent(infoHash, specStorage)
1253 cl.eachDhtServer(func(s DhtServer) {
1254 if cl.config.PeriodicallyAnnounceTorrentsToDht {
1255 go t.dhtAnnouncer(s)
1258 cl.torrents[infoHash] = t
1259 cl.clearAcceptLimits()
1260 t.updateWantPeersEvent()
1261 // Tickle Client.waitAccept, new torrent may want conns.
1262 cl.event.Broadcast()
1266 // Adds a torrent by InfoHash with a custom Storage implementation.
1267 // If the torrent already exists then this Storage is ignored and the
1268 // existing torrent returned with `new` set to `false`
1269 func (cl *Client) AddTorrentOpt(opts AddTorrentOpts) (t *Torrent, new bool) {
1270 infoHash := opts.InfoHash
1273 t, ok := cl.torrents[infoHash]
1279 t = cl.newTorrentOpt(opts)
1280 cl.eachDhtServer(func(s DhtServer) {
1281 if cl.config.PeriodicallyAnnounceTorrentsToDht {
1282 go t.dhtAnnouncer(s)
1285 cl.torrents[infoHash] = t
1286 cl.clearAcceptLimits()
1287 t.updateWantPeersEvent()
1288 // Tickle Client.waitAccept, new torrent may want conns.
1289 cl.event.Broadcast()
1293 type AddTorrentOpts struct {
1295 Storage storage.ClientImpl
1296 ChunkSize pp.Integer
1299 // Add or merge a torrent spec. Returns new if the torrent wasn't already in the client. See also
1300 // Torrent.MergeSpec.
1301 func (cl *Client) AddTorrentSpec(spec *TorrentSpec) (t *Torrent, new bool, err error) {
1302 t, new = cl.AddTorrentOpt(AddTorrentOpts{
1303 InfoHash: spec.InfoHash,
1304 Storage: spec.Storage,
1305 ChunkSize: spec.ChunkSize,
1309 // ChunkSize was already applied by adding a new Torrent, and MergeSpec disallows changing
1311 modSpec.ChunkSize = 0
1313 err = t.MergeSpec(&modSpec)
1314 if err != nil && new {
1320 type stringAddr string
1322 var _ net.Addr = stringAddr("")
1324 func (stringAddr) Network() string { return "" }
1325 func (me stringAddr) String() string { return string(me) }
1327 // The trackers will be merged with the existing ones. If the Info isn't yet known, it will be set.
1328 // spec.DisallowDataDownload/Upload will be read and applied
1329 // The display name is replaced if the new spec provides one. Note that any `Storage` is ignored.
1330 func (t *Torrent) MergeSpec(spec *TorrentSpec) error {
1331 if spec.DisplayName != "" {
1332 t.SetDisplayName(spec.DisplayName)
1334 if spec.InfoBytes != nil {
1335 err := t.SetInfoBytes(spec.InfoBytes)
1341 cl.AddDhtNodes(spec.DhtNodes)
1342 t.UseSources(spec.Sources)
1345 t.initialPieceCheckDisabled = spec.DisableInitialPieceCheck
1346 for _, url := range spec.Webseeds {
1349 for _, peerAddr := range spec.PeerAddrs {
1351 Addr: stringAddr(peerAddr),
1352 Source: PeerSourceDirect,
1356 if spec.ChunkSize != 0 {
1357 panic("chunk size cannot be changed for existing Torrent")
1359 t.addTrackers(spec.Trackers)
1361 t.dataDownloadDisallowed.SetBool(spec.DisallowDataDownload)
1362 t.dataUploadDisallowed = spec.DisallowDataUpload
1366 func (cl *Client) dropTorrent(infoHash metainfo.Hash, wg *sync.WaitGroup) (err error) {
1367 t, ok := cl.torrents[infoHash]
1369 err = fmt.Errorf("no such torrent")
1373 delete(cl.torrents, infoHash)
1377 func (cl *Client) allTorrentsCompleted() bool {
1378 for _, t := range cl.torrents {
1382 if !t.haveAllPieces() {
1389 // Returns true when all torrents are completely downloaded and false if the
1390 // client is stopped before that.
1391 func (cl *Client) WaitAll() bool {
1394 for !cl.allTorrentsCompleted() {
1395 if cl.closed.IsSet() {
1403 // Returns handles to all the torrents loaded in the Client.
1404 func (cl *Client) Torrents() []*Torrent {
1407 return cl.torrentsAsSlice()
1410 func (cl *Client) torrentsAsSlice() (ret []*Torrent) {
1411 for _, t := range cl.torrents {
1412 ret = append(ret, t)
1417 func (cl *Client) AddMagnet(uri string) (T *Torrent, err error) {
1418 spec, err := TorrentSpecFromMagnetUri(uri)
1422 T, _, err = cl.AddTorrentSpec(spec)
1426 func (cl *Client) AddTorrent(mi *metainfo.MetaInfo) (T *Torrent, err error) {
1427 ts, err := TorrentSpecFromMetaInfoErr(mi)
1431 T, _, err = cl.AddTorrentSpec(ts)
1435 func (cl *Client) AddTorrentFromFile(filename string) (T *Torrent, err error) {
1436 mi, err := metainfo.LoadFromFile(filename)
1440 return cl.AddTorrent(mi)
1443 func (cl *Client) DhtServers() []DhtServer {
1444 return cl.dhtServers
1447 func (cl *Client) AddDhtNodes(nodes []string) {
1448 for _, n := range nodes {
1449 hmp := missinggo.SplitHostMaybePort(n)
1450 ip := net.ParseIP(hmp.Host)
1452 cl.logger.Printf("won't add DHT node with bad IP: %q", hmp.Host)
1455 ni := krpc.NodeInfo{
1456 Addr: krpc.NodeAddr{
1461 cl.eachDhtServer(func(s DhtServer) {
1467 func (cl *Client) banPeerIP(ip net.IP) {
1468 // We can't take this from string, because it will lose netip's v4on6. net.ParseIP parses v4
1469 // addresses directly to v4on6, which doesn't compare equal with v4.
1470 ipAddr, ok := netip.AddrFromSlice(ip)
1474 generics.MakeMapIfNilAndSet(&cl.badPeerIPs, ipAddr, struct{}{})
1475 for _, t := range cl.torrents {
1476 t.iterPeers(func(p *Peer) {
1477 if p.remoteIp().Equal(ip) {
1478 t.logger.Levelf(log.Warning, "dropping peer %v with banned ip %v", p, ip)
1479 // Should this be a close?
1486 type newConnectionOpts struct {
1488 remoteAddr PeerRemoteAddr
1489 localPublicAddr peerLocalPublicAddr
1494 func (cl *Client) newConnection(nc net.Conn, opts newConnectionOpts) (c *PeerConn) {
1495 if opts.network == "" {
1496 panic(opts.remoteAddr)
1500 outgoing: opts.outgoing,
1503 PeerMaxRequests: 250,
1505 RemoteAddr: opts.remoteAddr,
1506 localPublicAddr: opts.localPublicAddr,
1507 Network: opts.network,
1508 callbacks: &cl.config.Callbacks,
1510 connString: opts.connString,
1513 c.initRequestState()
1514 // TODO: Need to be much more explicit about this, including allowing non-IP bannable addresses.
1515 if opts.remoteAddr != nil {
1516 netipAddrPort, err := netip.ParseAddrPort(opts.remoteAddr.String())
1518 c.bannableAddr = Some(netipAddrPort.Addr())
1522 c.logger = cl.logger.WithDefaultLevel(log.Warning).WithContextValue(c)
1523 c.setRW(connStatsReadWriter{nc, c})
1524 c.r = &rateLimitedReader{
1525 l: cl.config.DownloadRateLimiter,
1528 c.logger.WithDefaultLevel(log.Debug).Printf("initialized with remote %v over network %v (outgoing=%t)", opts.remoteAddr, opts.network, opts.outgoing)
1529 for _, f := range cl.config.Callbacks.NewPeer {
1535 func (cl *Client) onDHTAnnouncePeer(ih metainfo.Hash, ip net.IP, port int, portOk bool) {
1542 t.addPeers([]PeerInfo{{
1543 Addr: ipPortAddr{ip, port},
1544 Source: PeerSourceDhtAnnouncePeer,
1548 func firstNotNil(ips ...net.IP) net.IP {
1549 for _, ip := range ips {
1557 func (cl *Client) eachListener(f func(Listener) bool) {
1558 for _, s := range cl.listeners {
1565 func (cl *Client) findListener(f func(Listener) bool) (ret Listener) {
1566 for i := 0; i < len(cl.listeners); i += 1 {
1567 if ret = cl.listeners[i]; f(ret) {
1574 func (cl *Client) publicIp(peer net.IP) net.IP {
1575 // TODO: Use BEP 10 to determine how peers are seeing us.
1576 if peer.To4() != nil {
1578 cl.config.PublicIp4,
1579 cl.findListenerIp(func(ip net.IP) bool { return ip.To4() != nil }),
1584 cl.config.PublicIp6,
1585 cl.findListenerIp(func(ip net.IP) bool { return ip.To4() == nil }),
1589 func (cl *Client) findListenerIp(f func(net.IP) bool) net.IP {
1590 l := cl.findListener(
1591 func(l Listener) bool {
1592 return f(addrIpOrNil(l.Addr()))
1598 return addrIpOrNil(l.Addr())
1601 // Our IP as a peer should see it.
1602 func (cl *Client) publicAddr(peer net.IP) IpPort {
1603 return IpPort{IP: cl.publicIp(peer), Port: uint16(cl.incomingPeerPort())}
1606 // ListenAddrs addresses currently being listened to.
1607 func (cl *Client) ListenAddrs() (ret []net.Addr) {
1609 ret = make([]net.Addr, len(cl.listeners))
1610 for i := 0; i < len(cl.listeners); i += 1 {
1611 ret[i] = cl.listeners[i].Addr()
1617 func (cl *Client) PublicIPs() (ips []net.IP) {
1618 if ip := cl.config.PublicIp4; ip != nil {
1619 ips = append(ips, ip)
1621 if ip := cl.config.PublicIp6; ip != nil {
1622 ips = append(ips, ip)
1627 func (cl *Client) onBadAccept(addr PeerRemoteAddr) {
1628 ipa, ok := tryIpPortFromNetAddr(addr)
1632 ip := maskIpForAcceptLimiting(ipa.IP)
1633 if cl.acceptLimiter == nil {
1634 cl.acceptLimiter = make(map[ipStr]int)
1636 cl.acceptLimiter[ipStr(ip.String())]++
1639 func maskIpForAcceptLimiting(ip net.IP) net.IP {
1640 if ip4 := ip.To4(); ip4 != nil {
1641 return ip4.Mask(net.CIDRMask(24, 32))
1646 func (cl *Client) clearAcceptLimits() {
1647 cl.acceptLimiter = nil
1650 func (cl *Client) acceptLimitClearer() {
1653 case <-cl.closed.Done():
1655 case <-time.After(15 * time.Minute):
1657 cl.clearAcceptLimits()
1663 func (cl *Client) rateLimitAccept(ip net.IP) bool {
1664 if cl.config.DisableAcceptRateLimiting {
1667 return cl.acceptLimiter[ipStr(maskIpForAcceptLimiting(ip).String())] > 0
1670 func (cl *Client) rLock() {
1674 func (cl *Client) rUnlock() {
1678 func (cl *Client) lock() {
1682 func (cl *Client) unlock() {
1686 func (cl *Client) locker() *lockWithDeferreds {
1690 func (cl *Client) String() string {
1691 return fmt.Sprintf("<%[1]T %[1]p>", cl)
1694 // Returns connection-level aggregate stats at the Client level. See the comment on
1695 // TorrentStats.ConnStats.
1696 func (cl *Client) ConnStats() ConnStats {
1697 return cl.stats.Copy()