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 . "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"
38 "golang.org/x/time/rate"
40 "github.com/anacrolix/torrent/bencode"
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 request_strategy "github.com/anacrolix/torrent/request-strategy"
47 "github.com/anacrolix/torrent/storage"
48 "github.com/anacrolix/torrent/tracker"
49 "github.com/anacrolix/torrent/webtorrent"
52 // Clients contain zero or more Torrents. A Client manages a blocklist, the
53 // TCP/UDP protocol ports, and DHT as desired.
55 // An aggregate of stats over all connections. First in struct to ensure 64-bit alignment of
61 closed chansync.SetOnce
67 defaultStorage *storage.Client
71 dhtServers []DhtServer
72 ipBlockList iplist.Ranger
74 // Set of addresses that have our client ID. This intentionally will
75 // include ourselves if we end up trying to connect to our own address
76 // through legitimate channels.
77 dopplegangerAddrs map[string]struct{}
78 badPeerIPs map[netip.Addr]struct{}
79 torrents map[InfoHash]*Torrent
80 pieceRequestOrder map[interface{}]*request_strategy.PieceRequestOrder
82 acceptLimiter map[ipStr]int
83 dialRateLimiter *rate.Limiter
86 websocketTrackers websocketTrackers
88 activeAnnounceLimiter limiter.Instance
89 httpClient *http.Client
94 func (cl *Client) BadPeerIPs() (ips []string) {
96 ips = cl.badPeerIPsLocked()
101 func (cl *Client) badPeerIPsLocked() (ips []string) {
102 ips = make([]string, len(cl.badPeerIPs))
104 for k := range cl.badPeerIPs {
111 func (cl *Client) PeerID() PeerID {
115 // Returns the port number for the first listener that has one. No longer assumes that all port
116 // numbers are the same, due to support for custom listeners. Returns zero if no port number is
118 func (cl *Client) LocalPort() (port int) {
119 for i := 0; i < len(cl.listeners); i += 1 {
120 if port = addrPortOrZero(cl.listeners[i].Addr()); port != 0 {
127 func writeDhtServerStatus(w io.Writer, s DhtServer) {
128 dhtStats := s.Stats()
129 fmt.Fprintf(w, " ID: %x\n", s.ID())
130 spew.Fdump(w, dhtStats)
133 // Writes out a human readable status of the client, such as for writing to a
135 func (cl *Client) WriteStatus(_w io.Writer) {
138 w := bufio.NewWriter(_w)
140 fmt.Fprintf(w, "Listen port: %d\n", cl.LocalPort())
141 fmt.Fprintf(w, "Peer ID: %+q\n", cl.PeerID())
142 fmt.Fprintf(w, "Extension bits: %v\n", cl.config.Extensions)
143 fmt.Fprintf(w, "Announce key: %x\n", cl.announceKey())
144 fmt.Fprintf(w, "Banned IPs: %d\n", len(cl.badPeerIPsLocked()))
145 cl.eachDhtServer(func(s DhtServer) {
146 fmt.Fprintf(w, "%s DHT server at %s:\n", s.Addr().Network(), s.Addr().String())
147 writeDhtServerStatus(w, s)
149 spew.Fdump(w, &cl.stats)
150 torrentsSlice := cl.torrentsAsSlice()
151 fmt.Fprintf(w, "# Torrents: %d\n", len(torrentsSlice))
153 sort.Slice(torrentsSlice, func(l, r int) bool {
154 return torrentsSlice[l].infoHash.AsString() < torrentsSlice[r].infoHash.AsString()
156 for _, t := range torrentsSlice {
158 fmt.Fprint(w, "<unknown name>")
160 fmt.Fprint(w, t.name())
166 "%f%% of %d bytes (%s)",
167 100*(1-float64(t.bytesMissingLocked())/float64(t.info.TotalLength())),
169 humanize.Bytes(uint64(t.length())))
171 w.WriteString("<missing metainfo>")
179 func (cl *Client) initLogger() {
180 logger := cl.config.Logger
185 logger = logger.FilterLevel(log.Debug)
187 cl.logger = logger.WithValues(cl)
190 func (cl *Client) announceKey() int32 {
191 return int32(binary.BigEndian.Uint32(cl.peerID[16:20]))
194 // Initializes a bare minimum Client. *Client and *ClientConfig must not be nil.
195 func (cl *Client) init(cfg *ClientConfig) {
197 generics.MakeMap(&cl.dopplegangerAddrs)
198 cl.torrents = make(map[metainfo.Hash]*Torrent)
199 cl.dialRateLimiter = rate.NewLimiter(10, 10)
200 cl.activeAnnounceLimiter.SlotsPerKey = 2
201 cl.event.L = cl.locker()
202 cl.ipBlockList = cfg.IPBlocklist
203 cl.httpClient = &http.Client{
204 Transport: &http.Transport{
205 Proxy: cfg.HTTPProxy,
206 DialContext: cfg.HTTPDialContext,
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 DialContext: cl.config.TrackerDialContext,
302 OnConn: func(dc datachannel.ReadWriteCloser, dcc webtorrent.DataChannelContext) {
305 t, ok := cl.torrents[dcc.InfoHash]
307 cl.logger.WithDefaultLevel(log.Warning).Printf(
308 "got webrtc conn for unloaded torrent with infohash %x",
314 go t.onWebRtcConn(dc, dcc)
321 func (cl *Client) AddDhtServer(d DhtServer) {
322 cl.dhtServers = append(cl.dhtServers, d)
325 // Adds a Dialer for outgoing connections. All Dialers are used when attempting to connect to a
326 // given address for any Torrent.
327 func (cl *Client) AddDialer(d Dialer) {
330 cl.dialers = append(cl.dialers, d)
331 for _, t := range cl.torrents {
336 func (cl *Client) Listeners() []Listener {
340 // Registers a Listener, and starts Accepting on it. You must Close Listeners provided this way
342 func (cl *Client) AddListener(l Listener) {
343 cl.listeners = append(cl.listeners, l)
344 if cl.config.AcceptPeerConnections {
345 go cl.acceptConnections(l)
349 func (cl *Client) firewallCallback(net.Addr) bool {
351 block := !cl.wantConns() || !cl.config.AcceptPeerConnections
354 torrent.Add("connections firewalled", 1)
356 torrent.Add("connections not firewalled", 1)
361 func (cl *Client) listenOnNetwork(n network) bool {
362 if n.Ipv4 && cl.config.DisableIPv4 {
365 if n.Ipv6 && cl.config.DisableIPv6 {
368 if n.Tcp && cl.config.DisableTCP {
371 if n.Udp && cl.config.DisableUTP && cl.config.NoDHT {
377 func (cl *Client) listenNetworks() (ns []network) {
378 for _, n := range allPeerNetworks {
379 if cl.listenOnNetwork(n) {
386 // Creates an anacrolix/dht Server, as would be done internally in NewClient, for the given conn.
387 func (cl *Client) NewAnacrolixDhtServer(conn net.PacketConn) (s *dht.Server, err error) {
388 logger := cl.logger.WithNames("dht", conn.LocalAddr().String())
389 cfg := dht.ServerConfig{
390 IPBlocklist: cl.ipBlockList,
392 OnAnnouncePeer: cl.onDHTAnnouncePeer,
393 PublicIP: func() net.IP {
394 if connIsIpv6(conn) && cl.config.PublicIp6 != nil {
395 return cl.config.PublicIp6
397 return cl.config.PublicIp4
399 StartingNodes: cl.config.DhtStartingNodes(conn.LocalAddr().Network()),
400 OnQuery: cl.config.DHTOnQuery,
403 if f := cl.config.ConfigureAnacrolixDhtServer; f != nil {
406 s, err = dht.NewServer(&cfg)
408 go s.TableMaintainer()
413 func (cl *Client) Closed() events.Done {
414 return cl.closed.Done()
417 func (cl *Client) eachDhtServer(f func(DhtServer)) {
418 for _, ds := range cl.dhtServers {
423 // Stops the client. All connections to peers are closed and all activity will come to a halt.
424 func (cl *Client) Close() (errs []error) {
425 var closeGroup sync.WaitGroup // For concurrent cleanup to complete before returning
427 for _, t := range cl.torrents {
428 err := t.close(&closeGroup)
430 errs = append(errs, err)
433 for i := range cl.onClose {
434 cl.onClose[len(cl.onClose)-1-i]()
439 closeGroup.Wait() // defer is LIFO. We want to Wait() after cl.unlock()
443 func (cl *Client) ipBlockRange(ip net.IP) (r iplist.Range, blocked bool) {
444 if cl.ipBlockList == nil {
447 return cl.ipBlockList.Lookup(ip)
450 func (cl *Client) ipIsBlocked(ip net.IP) bool {
451 _, blocked := cl.ipBlockRange(ip)
455 func (cl *Client) wantConns() bool {
456 if cl.config.AlwaysWantConns {
459 for _, t := range cl.torrents {
467 // TODO: Apply filters for non-standard networks, particularly rate-limiting.
468 func (cl *Client) rejectAccepted(conn net.Conn) error {
470 return errors.New("don't want conns right now")
472 ra := conn.RemoteAddr()
473 if rip := addrIpOrNil(ra); rip != nil {
474 if cl.config.DisableIPv4Peers && rip.To4() != nil {
475 return errors.New("ipv4 peers disabled")
477 if cl.config.DisableIPv4 && len(rip) == net.IPv4len {
478 return errors.New("ipv4 disabled")
480 if cl.config.DisableIPv6 && len(rip) == net.IPv6len && rip.To4() == nil {
481 return errors.New("ipv6 disabled")
483 if cl.rateLimitAccept(rip) {
484 return errors.New("source IP accepted rate limited")
486 if cl.badPeerIPPort(rip, missinggo.AddrPort(ra)) {
487 return errors.New("bad source addr")
493 func (cl *Client) acceptConnections(l Listener) {
495 conn, err := l.Accept()
496 torrent.Add("client listener accepts", 1)
497 conn = pproffd.WrapNetConn(conn)
499 closed := cl.closed.IsSet()
501 if !closed && conn != nil {
502 reject = cl.rejectAccepted(conn)
512 log.Fmsg("error accepting connection: %s", err).LogLevel(log.Debug, cl.logger)
517 torrent.Add("rejected accepted connections", 1)
518 cl.logger.LazyLog(log.Debug, func() log.Msg {
519 return log.Fmsg("rejecting accepted conn: %v", reject)
523 go cl.incomingConnection(conn)
525 cl.logger.LazyLog(log.Debug, func() log.Msg {
526 return log.Fmsg("accepted %q connection at %q from %q",
532 torrent.Add(fmt.Sprintf("accepted conn remote IP len=%d", len(addrIpOrNil(conn.RemoteAddr()))), 1)
533 torrent.Add(fmt.Sprintf("accepted conn network=%s", conn.RemoteAddr().Network()), 1)
534 torrent.Add(fmt.Sprintf("accepted on %s listener", l.Addr().Network()), 1)
539 // Creates the PeerConn.connString for a regular net.Conn PeerConn.
540 func regularNetConnPeerConnConnString(nc net.Conn) string {
541 return fmt.Sprintf("%s-%s", nc.LocalAddr(), nc.RemoteAddr())
544 func (cl *Client) incomingConnection(nc net.Conn) {
546 if tc, ok := nc.(*net.TCPConn); ok {
549 remoteAddr, _ := tryIpPortFromNetAddr(nc.RemoteAddr())
550 c := cl.newConnection(
554 remoteAddr: nc.RemoteAddr(),
555 localPublicAddr: cl.publicAddr(remoteAddr.IP),
556 network: nc.RemoteAddr().Network(),
557 connString: regularNetConnPeerConnConnString(nc),
564 c.Discovery = PeerSourceIncoming
565 cl.runReceivedConn(c)
568 // Returns a handle to the given torrent, if it's present in the client.
569 func (cl *Client) Torrent(ih metainfo.Hash) (t *Torrent, ok bool) {
572 t, ok = cl.torrents[ih]
576 func (cl *Client) torrent(ih metainfo.Hash) *Torrent {
577 return cl.torrents[ih]
580 type DialResult struct {
585 func countDialResult(err error) {
587 torrent.Add("successful dials", 1)
589 torrent.Add("unsuccessful dials", 1)
593 func reducedDialTimeout(minDialTimeout, max time.Duration, halfOpenLimit, pendingPeers int) (ret time.Duration) {
594 ret = max / time.Duration((pendingPeers+halfOpenLimit)/halfOpenLimit)
595 if ret < minDialTimeout {
601 // Returns whether an address is known to connect to a client with our own ID.
602 func (cl *Client) dopplegangerAddr(addr string) bool {
603 _, ok := cl.dopplegangerAddrs[addr]
607 // Returns a connection over UTP or TCP, whichever is first to connect.
608 func (cl *Client) dialFirst(ctx context.Context, addr string) (res DialResult) {
609 return DialFirst(ctx, addr, cl.dialers)
612 // Returns a connection over UTP or TCP, whichever is first to connect.
613 func DialFirst(ctx context.Context, addr string, dialers []Dialer) (res DialResult) {
615 t := perf.NewTimer(perf.CallerName(0))
618 t.Mark(fmt.Sprintf("returned no conn (context: %v)", ctx.Err()))
620 t.Mark("returned conn over " + res.Dialer.DialerNetwork())
624 ctx, cancel := context.WithCancel(ctx)
625 // As soon as we return one connection, cancel the others.
628 resCh := make(chan DialResult, left)
629 for _, _s := range dialers {
634 dialFromSocket(ctx, s, addr),
639 // Wait for a successful connection.
641 defer perf.ScopeTimer()()
642 for ; left > 0 && res.Conn == nil; left-- {
646 // There are still incompleted dials.
648 for ; left > 0; left-- {
649 conn := (<-resCh).Conn
656 go torrent.Add(fmt.Sprintf("network dialed first: %s", res.Conn.RemoteAddr().Network()), 1)
661 func dialFromSocket(ctx context.Context, s Dialer, addr string) net.Conn {
662 c, err := s.Dial(ctx, addr)
663 // This is a bit optimistic, but it looks non-trivial to thread this through the proxy code. Set
664 // it now in case we close the connection forthwith.
665 if tc, ok := c.(*net.TCPConn); ok {
672 func forgettableDialError(err error) bool {
673 return strings.Contains(err.Error(), "no suitable address found")
676 func (cl *Client) noLongerHalfOpen(t *Torrent, addr string) {
677 if _, ok := t.halfOpen[addr]; !ok {
678 panic("invariant broken")
680 delete(t.halfOpen, addr)
682 for _, t := range cl.torrents {
687 // Performs initiator handshakes and returns a connection. Returns nil *connection if no connection
688 // for valid reasons.
689 func (cl *Client) initiateProtocolHandshakes(
694 newConnOpts newConnectionOpts,
696 c *PeerConn, err error,
698 c = cl.newConnection(nc, newConnOpts)
699 c.headerEncrypted = encryptHeader
700 ctx, cancel := context.WithTimeout(ctx, cl.config.HandshakesTimeout)
702 dl, ok := ctx.Deadline()
706 err = nc.SetDeadline(dl)
710 err = cl.initiateHandshakes(c, t)
714 // Returns nil connection and nil error if no connection could be established for valid reasons.
715 func (cl *Client) establishOutgoingConnEx(t *Torrent, addr PeerRemoteAddr, obfuscatedHeader bool) (*PeerConn, error) {
716 dialCtx, cancel := context.WithTimeout(context.Background(), func() time.Duration {
719 return t.dialTimeout()
722 dr := cl.dialFirst(dialCtx, addr.String())
725 if dialCtx.Err() != nil {
726 return nil, fmt.Errorf("dialing: %w", dialCtx.Err())
728 return nil, errors.New("dial failed")
730 addrIpPort, _ := tryIpPortFromNetAddr(addr)
731 c, err := cl.initiateProtocolHandshakes(context.Background(), nc, t, obfuscatedHeader, newConnectionOpts{
734 // It would be possible to retrieve a public IP from the dialer used here?
735 localPublicAddr: cl.publicAddr(addrIpPort.IP),
736 network: dr.Dialer.DialerNetwork(),
737 connString: regularNetConnPeerConnConnString(nc),
745 // Returns nil connection and nil error if no connection could be established
746 // for valid reasons.
747 func (cl *Client) establishOutgoingConn(t *Torrent, addr PeerRemoteAddr) (c *PeerConn, err error) {
748 torrent.Add("establish outgoing connection", 1)
749 obfuscatedHeaderFirst := cl.config.HeaderObfuscationPolicy.Preferred
750 c, err = cl.establishOutgoingConnEx(t, addr, obfuscatedHeaderFirst)
752 torrent.Add("initiated conn with preferred header obfuscation", 1)
755 // cl.logger.Printf("error establishing connection to %s (obfuscatedHeader=%t): %v", addr, obfuscatedHeaderFirst, err)
756 if cl.config.HeaderObfuscationPolicy.RequirePreferred {
757 // We should have just tried with the preferred header obfuscation. If it was required,
758 // there's nothing else to try.
761 // Try again with encryption if we didn't earlier, or without if we did.
762 c, err = cl.establishOutgoingConnEx(t, addr, !obfuscatedHeaderFirst)
764 torrent.Add("initiated conn with fallback header obfuscation", 1)
766 // cl.logger.Printf("error establishing fallback connection to %v: %v", addr, err)
770 // Called to dial out and run a connection. The addr we're given is already
771 // considered half-open.
772 func (cl *Client) outgoingConnection(t *Torrent, addr PeerRemoteAddr, ps PeerSource, trusted bool) {
773 cl.dialRateLimiter.Wait(context.Background())
774 c, err := cl.establishOutgoingConn(t, addr)
776 c.conn.SetWriteDeadline(time.Time{})
780 // Don't release lock between here and addPeerConn, unless it's for
782 cl.noLongerHalfOpen(t, addr.String())
785 cl.logger.Levelf(log.Debug, "error establishing outgoing connection to %v: %v", addr, err)
792 t.runHandshookConnLoggingErr(c)
795 // The port number for incoming peer connections. 0 if the client isn't listening.
796 func (cl *Client) incomingPeerPort() int {
797 return cl.LocalPort()
800 func (cl *Client) initiateHandshakes(c *PeerConn, t *Torrent) error {
801 if c.headerEncrypted {
804 rw, c.cryptoMethod, err = mse.InitiateHandshake(
811 cl.config.CryptoProvides,
815 return fmt.Errorf("header obfuscation handshake: %w", err)
818 ih, err := cl.connBtHandshake(c, &t.infoHash)
820 return fmt.Errorf("bittorrent protocol handshake: %w", err)
822 if ih != t.infoHash {
823 return errors.New("bittorrent protocol handshake: peer infohash didn't match")
828 // Calls f with any secret keys. Note that it takes the Client lock, and so must be used from code
829 // that won't also try to take the lock. This saves us copying all the infohashes everytime.
830 func (cl *Client) forSkeys(f func([]byte) bool) {
833 if false { // Emulate the bug from #114
835 for ih := range cl.torrents {
839 for range cl.torrents {
846 for ih := range cl.torrents {
853 func (cl *Client) handshakeReceiverSecretKeys() mse.SecretKeyIter {
854 if ret := cl.config.Callbacks.ReceiveEncryptedHandshakeSkeys; ret != nil {
860 // Do encryption and bittorrent handshakes as receiver.
861 func (cl *Client) receiveHandshakes(c *PeerConn) (t *Torrent, err error) {
862 defer perf.ScopeTimerErr(&err)()
864 rw, c.headerEncrypted, c.cryptoMethod, err = handleEncryption(c.rw(), cl.handshakeReceiverSecretKeys(), cl.config.HeaderObfuscationPolicy, cl.config.CryptoSelector)
866 if err == nil || err == mse.ErrNoSecretKeyMatch {
867 if c.headerEncrypted {
868 torrent.Add("handshakes received encrypted", 1)
870 torrent.Add("handshakes received unencrypted", 1)
873 torrent.Add("handshakes received with error while handling encryption", 1)
876 if err == mse.ErrNoSecretKeyMatch {
881 if cl.config.HeaderObfuscationPolicy.RequirePreferred && c.headerEncrypted != cl.config.HeaderObfuscationPolicy.Preferred {
882 err = errors.New("connection does not have required header obfuscation")
885 ih, err := cl.connBtHandshake(c, nil)
887 return nil, fmt.Errorf("during bt handshake: %w", err)
895 var successfulPeerWireProtocolHandshakePeerReservedBytes expvar.Map
899 "successful_peer_wire_protocol_handshake_peer_reserved_bytes",
900 &successfulPeerWireProtocolHandshakePeerReservedBytes)
903 func (cl *Client) connBtHandshake(c *PeerConn, ih *metainfo.Hash) (ret metainfo.Hash, err error) {
904 res, err := pp.Handshake(c.rw(), ih, cl.peerID, cl.config.Extensions)
908 successfulPeerWireProtocolHandshakePeerReservedBytes.Add(res.PeerExtensionBits.String(), 1)
910 c.PeerExtensionBytes = res.PeerExtensionBits
911 c.PeerID = res.PeerID
912 c.completedHandshake = time.Now()
913 if cb := cl.config.Callbacks.CompletedHandshake; cb != nil {
919 func (cl *Client) runReceivedConn(c *PeerConn) {
920 err := c.conn.SetDeadline(time.Now().Add(cl.config.HandshakesTimeout))
924 t, err := cl.receiveHandshakes(c)
926 cl.logger.LazyLog(log.Debug, func() log.Msg {
928 "error receiving handshakes on %v: %s", c, err,
930 "network", c.Network,
933 torrent.Add("error receiving handshake", 1)
935 cl.onBadAccept(c.RemoteAddr)
940 torrent.Add("received handshake for unloaded torrent", 1)
941 cl.logger.LazyLog(log.Debug, func() log.Msg {
942 return log.Fmsg("received handshake for unloaded torrent")
945 cl.onBadAccept(c.RemoteAddr)
949 torrent.Add("received handshake for loaded torrent", 1)
950 c.conn.SetWriteDeadline(time.Time{})
953 t.runHandshookConnLoggingErr(c)
956 // Client lock must be held before entering this.
957 func (cl *Client) runHandshookConn(c *PeerConn, t *Torrent) error {
959 for i, b := range cl.config.MinPeerExtensions {
960 if c.PeerExtensionBytes[i]&b != b {
961 return fmt.Errorf("peer did not meet minimum peer extensions: %x", c.PeerExtensionBytes[:])
964 if c.PeerID == cl.peerID {
967 addr := c.RemoteAddr.String()
968 cl.dopplegangerAddrs[addr] = struct{}{}
970 // Because the remote address is not necessarily the same as its client's torrent listen
971 // address, we won't record the remote address as a doppleganger. Instead, the initiator
972 // can record *us* as the doppleganger.
974 t.logger.Levelf(log.Debug, "local and remote peer ids are the same")
977 c.r = deadlineReader{c.conn, c.r}
978 completedHandshakeConnectionFlags.Add(c.connectionFlags(), 1)
979 if connIsIpv6(c.conn) {
980 torrent.Add("completed handshake over ipv6", 1)
982 if err := t.addPeerConn(c); err != nil {
983 return fmt.Errorf("adding connection: %w", err)
985 defer t.dropConnection(c)
986 c.startMessageWriter()
987 cl.sendInitialMessages(c, t)
988 c.initUpdateRequestsTimer()
989 err := c.mainReadLoop()
991 return fmt.Errorf("main read loop: %w", err)
998 func (p *Peer) initUpdateRequestsTimer() {
1000 if p.updateRequestsTimer != nil {
1001 panic(p.updateRequestsTimer)
1004 if enableUpdateRequestsTimer {
1005 p.updateRequestsTimer = time.AfterFunc(math.MaxInt64, p.updateRequestsTimerFunc)
1009 const peerUpdateRequestsTimerReason = "updateRequestsTimer"
1011 func (c *Peer) updateRequestsTimerFunc() {
1013 defer c.locker().Unlock()
1014 if c.closed.IsSet() {
1017 if c.isLowOnRequests() {
1018 // If there are no outstanding requests, then a request update should have already run.
1021 if d := time.Since(c.lastRequestUpdate); d < updateRequestsTimerDuration {
1022 // These should be benign, Timer.Stop doesn't guarantee that its function won't run if it's
1023 // already been fired.
1024 torrent.Add("spurious timer requests updates", 1)
1027 c.updateRequests(peerUpdateRequestsTimerReason)
1030 // Maximum pending requests we allow peers to send us. If peer requests are buffered on read, this
1031 // instructs the amount of memory that might be used to cache pending writes. Assuming 512KiB
1032 // (1<<19) cached for sending, for 16KiB (1<<14) chunks.
1033 const localClientReqq = 1024
1035 // See the order given in Transmission's tr_peerMsgsNew.
1036 func (cl *Client) sendInitialMessages(conn *PeerConn, torrent *Torrent) {
1037 if conn.PeerExtensionBytes.SupportsExtended() && cl.config.Extensions.SupportsExtended() {
1038 conn.write(pp.Message{
1040 ExtendedID: pp.HandshakeExtendedID,
1041 ExtendedPayload: func() []byte {
1042 msg := pp.ExtendedHandshakeMessage{
1043 M: map[pp.ExtensionName]pp.ExtensionNumber{
1044 pp.ExtensionNameMetadata: metadataExtendedId,
1046 V: cl.config.ExtendedHandshakeClientVersion,
1047 Reqq: localClientReqq,
1048 YourIp: pp.CompactIp(conn.remoteIp()),
1049 Encryption: cl.config.HeaderObfuscationPolicy.Preferred || !cl.config.HeaderObfuscationPolicy.RequirePreferred,
1050 Port: cl.incomingPeerPort(),
1051 MetadataSize: torrent.metadataSize(),
1052 // TODO: We can figure these out specific to the socket used.
1053 Ipv4: pp.CompactIp(cl.config.PublicIp4.To4()),
1054 Ipv6: cl.config.PublicIp6.To16(),
1056 if !cl.config.DisablePEX {
1057 msg.M[pp.ExtensionNamePex] = pexExtendedId
1059 return bencode.MustMarshal(msg)
1064 if conn.fastEnabled() {
1065 if torrent.haveAllPieces() {
1066 conn.write(pp.Message{Type: pp.HaveAll})
1067 conn.sentHaves.AddRange(0, bitmap.BitRange(conn.t.NumPieces()))
1069 } else if !torrent.haveAnyPieces() {
1070 conn.write(pp.Message{Type: pp.HaveNone})
1071 conn.sentHaves.Clear()
1077 if conn.PeerExtensionBytes.SupportsDHT() && cl.config.Extensions.SupportsDHT() && cl.haveDhtServer() {
1078 conn.write(pp.Message{
1085 func (cl *Client) dhtPort() (ret uint16) {
1086 if len(cl.dhtServers) == 0 {
1089 return uint16(missinggo.AddrPort(cl.dhtServers[len(cl.dhtServers)-1].Addr()))
1092 func (cl *Client) haveDhtServer() bool {
1093 return len(cl.dhtServers) > 0
1096 // Process incoming ut_metadata message.
1097 func (cl *Client) gotMetadataExtensionMsg(payload []byte, t *Torrent, c *PeerConn) error {
1098 var d pp.ExtendedMetadataRequestMsg
1099 err := bencode.Unmarshal(payload, &d)
1100 if _, ok := err.(bencode.ErrUnusedTrailingBytes); ok {
1101 } else if err != nil {
1102 return fmt.Errorf("error unmarshalling bencode: %s", err)
1106 case pp.DataMetadataExtensionMsgType:
1107 c.allStats(add(1, func(cs *ConnStats) *Count { return &cs.MetadataChunksRead }))
1108 if !c.requestedMetadataPiece(piece) {
1109 return fmt.Errorf("got unexpected piece %d", piece)
1111 c.metadataRequests[piece] = false
1112 begin := len(payload) - d.PieceSize()
1113 if begin < 0 || begin >= len(payload) {
1114 return fmt.Errorf("data has bad offset in payload: %d", begin)
1116 t.saveMetadataPiece(piece, payload[begin:])
1117 c.lastUsefulChunkReceived = time.Now()
1118 err = t.maybeCompleteMetadata()
1120 // Log this at the Torrent-level, as we don't partition metadata by Peer yet, so we
1121 // don't know who to blame. TODO: Also errors can be returned here that aren't related
1122 // to verifying metadata, which should be fixed. This should be tagged with metadata, so
1123 // log consumers can filter for this message.
1124 t.logger.WithDefaultLevel(log.Warning).Printf("error completing metadata: %v", err)
1127 case pp.RequestMetadataExtensionMsgType:
1128 if !t.haveMetadataPiece(piece) {
1129 c.write(t.newMetadataExtensionMessage(c, pp.RejectMetadataExtensionMsgType, d.Piece, nil))
1132 start := (1 << 14) * piece
1133 c.logger.WithDefaultLevel(log.Debug).Printf("sending metadata piece %d", piece)
1134 c.write(t.newMetadataExtensionMessage(c, pp.DataMetadataExtensionMsgType, piece, t.metadataBytes[start:start+t.metadataPieceSize(piece)]))
1136 case pp.RejectMetadataExtensionMsgType:
1139 return errors.New("unknown msg_type value")
1143 func (cl *Client) badPeerAddr(addr PeerRemoteAddr) bool {
1144 if ipa, ok := tryIpPortFromNetAddr(addr); ok {
1145 return cl.badPeerIPPort(ipa.IP, ipa.Port)
1150 // Returns whether the IP address and port are considered "bad".
1151 func (cl *Client) badPeerIPPort(ip net.IP, port int) bool {
1152 if port == 0 || ip == nil {
1155 if cl.dopplegangerAddr(net.JoinHostPort(ip.String(), strconv.FormatInt(int64(port), 10))) {
1158 if _, ok := cl.ipBlockRange(ip); ok {
1161 ipAddr, ok := netip.AddrFromSlice(ip)
1165 if _, ok := cl.badPeerIPs[ipAddr]; ok {
1171 // Return a Torrent ready for insertion into a Client.
1172 func (cl *Client) newTorrent(ih metainfo.Hash, specStorage storage.ClientImpl) (t *Torrent) {
1173 return cl.newTorrentOpt(AddTorrentOpts{
1175 Storage: specStorage,
1179 // Return a Torrent ready for insertion into a Client.
1180 func (cl *Client) newTorrentOpt(opts AddTorrentOpts) (t *Torrent) {
1181 // use provided storage, if provided
1182 storageClient := cl.defaultStorage
1183 if opts.Storage != nil {
1184 storageClient = storage.NewClient(opts.Storage)
1189 infoHash: opts.InfoHash,
1190 peers: prioritizedPeers{
1192 getPrio: func(p PeerInfo) peerPriority {
1194 return bep40PriorityIgnoreError(cl.publicAddr(ipPort.IP), ipPort)
1197 conns: make(map[*PeerConn]struct{}, 2*cl.config.EstablishedConnsPerTorrent),
1199 halfOpen: make(map[string]PeerInfo),
1201 storageOpener: storageClient,
1202 maxEstablishedConns: cl.config.EstablishedConnsPerTorrent,
1204 metadataChanged: sync.Cond{
1207 webSeeds: make(map[string]*Peer),
1208 gotMetainfoC: make(chan struct{}),
1210 t.smartBanCache.Hash = sha1.Sum
1211 t.smartBanCache.Init()
1212 t.networkingEnabled.Set()
1213 t.logger = cl.logger.WithContextValue(t).WithNames("torrent", t.infoHash.HexString())
1214 t.sourcesLogger = t.logger.WithNames("sources")
1215 if opts.ChunkSize == 0 {
1216 opts.ChunkSize = defaultChunkSize
1218 t.setChunkSize(opts.ChunkSize)
1222 // A file-like handle to some torrent data resource.
1223 type Handle interface {
1230 func (cl *Client) AddTorrentInfoHash(infoHash metainfo.Hash) (t *Torrent, new bool) {
1231 return cl.AddTorrentInfoHashWithStorage(infoHash, nil)
1234 // Adds a torrent by InfoHash with a custom Storage implementation.
1235 // If the torrent already exists then this Storage is ignored and the
1236 // existing torrent returned with `new` set to `false`
1237 func (cl *Client) AddTorrentInfoHashWithStorage(infoHash metainfo.Hash, specStorage storage.ClientImpl) (t *Torrent, new bool) {
1240 t, ok := cl.torrents[infoHash]
1246 t = cl.newTorrent(infoHash, specStorage)
1247 cl.eachDhtServer(func(s DhtServer) {
1248 if cl.config.PeriodicallyAnnounceTorrentsToDht {
1249 go t.dhtAnnouncer(s)
1252 cl.torrents[infoHash] = t
1253 cl.clearAcceptLimits()
1254 t.updateWantPeersEvent()
1255 // Tickle Client.waitAccept, new torrent may want conns.
1256 cl.event.Broadcast()
1260 // Adds a torrent by InfoHash with a custom Storage implementation.
1261 // If the torrent already exists then this Storage is ignored and the
1262 // existing torrent returned with `new` set to `false`
1263 func (cl *Client) AddTorrentOpt(opts AddTorrentOpts) (t *Torrent, new bool) {
1264 infoHash := opts.InfoHash
1267 t, ok := cl.torrents[infoHash]
1273 t = cl.newTorrentOpt(opts)
1274 cl.eachDhtServer(func(s DhtServer) {
1275 if cl.config.PeriodicallyAnnounceTorrentsToDht {
1276 go t.dhtAnnouncer(s)
1279 cl.torrents[infoHash] = t
1280 cl.clearAcceptLimits()
1281 t.updateWantPeersEvent()
1282 // Tickle Client.waitAccept, new torrent may want conns.
1283 cl.event.Broadcast()
1287 type AddTorrentOpts struct {
1289 Storage storage.ClientImpl
1290 ChunkSize pp.Integer
1293 // Add or merge a torrent spec. Returns new if the torrent wasn't already in the client. See also
1294 // Torrent.MergeSpec.
1295 func (cl *Client) AddTorrentSpec(spec *TorrentSpec) (t *Torrent, new bool, err error) {
1296 t, new = cl.AddTorrentOpt(AddTorrentOpts{
1297 InfoHash: spec.InfoHash,
1298 Storage: spec.Storage,
1299 ChunkSize: spec.ChunkSize,
1303 // ChunkSize was already applied by adding a new Torrent, and MergeSpec disallows changing
1305 modSpec.ChunkSize = 0
1307 err = t.MergeSpec(&modSpec)
1308 if err != nil && new {
1314 type stringAddr string
1316 var _ net.Addr = stringAddr("")
1318 func (stringAddr) Network() string { return "" }
1319 func (me stringAddr) String() string { return string(me) }
1321 // The trackers will be merged with the existing ones. If the Info isn't yet known, it will be set.
1322 // spec.DisallowDataDownload/Upload will be read and applied
1323 // The display name is replaced if the new spec provides one. Note that any `Storage` is ignored.
1324 func (t *Torrent) MergeSpec(spec *TorrentSpec) error {
1325 if spec.DisplayName != "" {
1326 t.SetDisplayName(spec.DisplayName)
1328 if spec.InfoBytes != nil {
1329 err := t.SetInfoBytes(spec.InfoBytes)
1335 cl.AddDhtNodes(spec.DhtNodes)
1336 t.UseSources(spec.Sources)
1339 t.initialPieceCheckDisabled = spec.DisableInitialPieceCheck
1340 for _, url := range spec.Webseeds {
1343 for _, peerAddr := range spec.PeerAddrs {
1345 Addr: stringAddr(peerAddr),
1346 Source: PeerSourceDirect,
1350 if spec.ChunkSize != 0 {
1351 panic("chunk size cannot be changed for existing Torrent")
1353 t.addTrackers(spec.Trackers)
1355 t.dataDownloadDisallowed.SetBool(spec.DisallowDataDownload)
1356 t.dataUploadDisallowed = spec.DisallowDataUpload
1360 func (cl *Client) dropTorrent(infoHash metainfo.Hash, wg *sync.WaitGroup) (err error) {
1361 t, ok := cl.torrents[infoHash]
1363 err = fmt.Errorf("no such torrent")
1367 delete(cl.torrents, infoHash)
1371 func (cl *Client) allTorrentsCompleted() bool {
1372 for _, t := range cl.torrents {
1376 if !t.haveAllPieces() {
1383 // Returns true when all torrents are completely downloaded and false if the
1384 // client is stopped before that.
1385 func (cl *Client) WaitAll() bool {
1388 for !cl.allTorrentsCompleted() {
1389 if cl.closed.IsSet() {
1397 // Returns handles to all the torrents loaded in the Client.
1398 func (cl *Client) Torrents() []*Torrent {
1401 return cl.torrentsAsSlice()
1404 func (cl *Client) torrentsAsSlice() (ret []*Torrent) {
1405 for _, t := range cl.torrents {
1406 ret = append(ret, t)
1411 func (cl *Client) AddMagnet(uri string) (T *Torrent, err error) {
1412 spec, err := TorrentSpecFromMagnetUri(uri)
1416 T, _, err = cl.AddTorrentSpec(spec)
1420 func (cl *Client) AddTorrent(mi *metainfo.MetaInfo) (T *Torrent, err error) {
1421 ts, err := TorrentSpecFromMetaInfoErr(mi)
1425 T, _, err = cl.AddTorrentSpec(ts)
1429 func (cl *Client) AddTorrentFromFile(filename string) (T *Torrent, err error) {
1430 mi, err := metainfo.LoadFromFile(filename)
1434 return cl.AddTorrent(mi)
1437 func (cl *Client) DhtServers() []DhtServer {
1438 return cl.dhtServers
1441 func (cl *Client) AddDhtNodes(nodes []string) {
1442 for _, n := range nodes {
1443 hmp := missinggo.SplitHostMaybePort(n)
1444 ip := net.ParseIP(hmp.Host)
1446 cl.logger.Printf("won't add DHT node with bad IP: %q", hmp.Host)
1449 ni := krpc.NodeInfo{
1450 Addr: krpc.NodeAddr{
1455 cl.eachDhtServer(func(s DhtServer) {
1461 func (cl *Client) banPeerIP(ip net.IP) {
1462 // We can't take this from string, because it will lose netip's v4on6. net.ParseIP parses v4
1463 // addresses directly to v4on6, which doesn't compare equal with v4.
1464 ipAddr, ok := netip.AddrFromSlice(ip)
1468 generics.MakeMapIfNilAndSet(&cl.badPeerIPs, ipAddr, struct{}{})
1469 for _, t := range cl.torrents {
1470 t.iterPeers(func(p *Peer) {
1471 if p.remoteIp().Equal(ip) {
1472 t.logger.Levelf(log.Warning, "dropping peer %v with banned ip %v", p, ip)
1473 // Should this be a close?
1480 type newConnectionOpts struct {
1482 remoteAddr PeerRemoteAddr
1483 localPublicAddr peerLocalPublicAddr
1488 func (cl *Client) newConnection(nc net.Conn, opts newConnectionOpts) (c *PeerConn) {
1489 if opts.network == "" {
1490 panic(opts.remoteAddr)
1494 outgoing: opts.outgoing,
1497 PeerMaxRequests: 250,
1499 RemoteAddr: opts.remoteAddr,
1500 localPublicAddr: opts.localPublicAddr,
1501 Network: opts.network,
1502 callbacks: &cl.config.Callbacks,
1504 connString: opts.connString,
1507 c.initRequestState()
1508 // TODO: Need to be much more explicit about this, including allowing non-IP bannable addresses.
1509 if opts.remoteAddr != nil {
1510 netipAddrPort, err := netip.ParseAddrPort(opts.remoteAddr.String())
1512 c.bannableAddr = Some(netipAddrPort.Addr())
1516 c.logger = cl.logger.WithDefaultLevel(log.Warning).WithContextValue(c)
1517 c.setRW(connStatsReadWriter{nc, c})
1518 c.r = &rateLimitedReader{
1519 l: cl.config.DownloadRateLimiter,
1522 c.logger.WithDefaultLevel(log.Debug).Printf("initialized with remote %v over network %v (outgoing=%t)", opts.remoteAddr, opts.network, opts.outgoing)
1523 for _, f := range cl.config.Callbacks.NewPeer {
1529 func (cl *Client) onDHTAnnouncePeer(ih metainfo.Hash, ip net.IP, port int, portOk bool) {
1536 t.addPeers([]PeerInfo{{
1537 Addr: ipPortAddr{ip, port},
1538 Source: PeerSourceDhtAnnouncePeer,
1542 func firstNotNil(ips ...net.IP) net.IP {
1543 for _, ip := range ips {
1551 func (cl *Client) eachListener(f func(Listener) bool) {
1552 for _, s := range cl.listeners {
1559 func (cl *Client) findListener(f func(Listener) bool) (ret Listener) {
1560 for i := 0; i < len(cl.listeners); i += 1 {
1561 if ret = cl.listeners[i]; f(ret) {
1568 func (cl *Client) publicIp(peer net.IP) net.IP {
1569 // TODO: Use BEP 10 to determine how peers are seeing us.
1570 if peer.To4() != nil {
1572 cl.config.PublicIp4,
1573 cl.findListenerIp(func(ip net.IP) bool { return ip.To4() != nil }),
1578 cl.config.PublicIp6,
1579 cl.findListenerIp(func(ip net.IP) bool { return ip.To4() == nil }),
1583 func (cl *Client) findListenerIp(f func(net.IP) bool) net.IP {
1584 l := cl.findListener(
1585 func(l Listener) bool {
1586 return f(addrIpOrNil(l.Addr()))
1592 return addrIpOrNil(l.Addr())
1595 // Our IP as a peer should see it.
1596 func (cl *Client) publicAddr(peer net.IP) IpPort {
1597 return IpPort{IP: cl.publicIp(peer), Port: uint16(cl.incomingPeerPort())}
1600 // ListenAddrs addresses currently being listened to.
1601 func (cl *Client) ListenAddrs() (ret []net.Addr) {
1603 ret = make([]net.Addr, len(cl.listeners))
1604 for i := 0; i < len(cl.listeners); i += 1 {
1605 ret[i] = cl.listeners[i].Addr()
1611 func (cl *Client) PublicIPs() (ips []net.IP) {
1612 if ip := cl.config.PublicIp4; ip != nil {
1613 ips = append(ips, ip)
1615 if ip := cl.config.PublicIp6; ip != nil {
1616 ips = append(ips, ip)
1621 func (cl *Client) onBadAccept(addr PeerRemoteAddr) {
1622 ipa, ok := tryIpPortFromNetAddr(addr)
1626 ip := maskIpForAcceptLimiting(ipa.IP)
1627 if cl.acceptLimiter == nil {
1628 cl.acceptLimiter = make(map[ipStr]int)
1630 cl.acceptLimiter[ipStr(ip.String())]++
1633 func maskIpForAcceptLimiting(ip net.IP) net.IP {
1634 if ip4 := ip.To4(); ip4 != nil {
1635 return ip4.Mask(net.CIDRMask(24, 32))
1640 func (cl *Client) clearAcceptLimits() {
1641 cl.acceptLimiter = nil
1644 func (cl *Client) acceptLimitClearer() {
1647 case <-cl.closed.Done():
1649 case <-time.After(15 * time.Minute):
1651 cl.clearAcceptLimits()
1657 func (cl *Client) rateLimitAccept(ip net.IP) bool {
1658 if cl.config.DisableAcceptRateLimiting {
1661 return cl.acceptLimiter[ipStr(maskIpForAcceptLimiting(ip).String())] > 0
1664 func (cl *Client) rLock() {
1668 func (cl *Client) rUnlock() {
1672 func (cl *Client) lock() {
1676 func (cl *Client) unlock() {
1680 func (cl *Client) locker() *lockWithDeferreds {
1684 func (cl *Client) String() string {
1685 return fmt.Sprintf("<%[1]T %[1]p>", cl)
1688 // Returns connection-level aggregate stats at the Client level. See the comment on
1689 // TorrentStats.ConnStats.
1690 func (cl *Client) ConnStats() ConnStats {
1691 return cl.stats.Copy()