peer.go

   1 package torrent
   2
   3 import (
   4         "errors"
   5         "fmt"
   6         "io"
   7         "net"
   8         "strings"
   9         "sync/atomic"
  10         "time"
  11
  12         "github.com/RoaringBitmap/roaring"
  13         "github.com/anacrolix/chansync"
  14         . "github.com/anacrolix/generics"
  15         "github.com/anacrolix/log"
  16         "github.com/anacrolix/missinggo/iter"
  17         "github.com/anacrolix/missinggo/v2/bitmap"
  18         "github.com/anacrolix/multiless"
  19
  20         "github.com/anacrolix/torrent/internal/alloclim"
  21         "github.com/anacrolix/torrent/mse"
  22         pp "github.com/anacrolix/torrent/peer_protocol"
  23         request_strategy "github.com/anacrolix/torrent/request-strategy"
  24         "github.com/anacrolix/torrent/typed-roaring"
  25 )
  26
  27 type (
  28         Peer struct {
  29                 // First to ensure 64-bit alignment for atomics. See #262.
  30                 _stats ConnStats
  31
  32                 t *Torrent
  33
  34                 peerImpl
  35                 callbacks *Callbacks
  36
  37                 outgoing   bool
  38                 Network    string
  39                 RemoteAddr PeerRemoteAddr
  40                 // The local address as observed by the remote peer. WebRTC seems to get this right without needing hints from the
  41                 // config.
  42                 localPublicAddr peerLocalPublicAddr
  43                 bannableAddr    Option[bannableAddr]
  44                 // True if the connection is operating over MSE obfuscation.
  45                 headerEncrypted bool
  46                 cryptoMethod    mse.CryptoMethod
  47                 Discovery       PeerSource
  48                 trusted         bool
  49                 closed          chansync.SetOnce
  50                 // Set true after we've added our ConnStats generated during handshake to
  51                 // other ConnStat instances as determined when the *Torrent became known.
  52                 reconciledHandshakeStats bool
  53
  54                 lastMessageReceived     time.Time
  55                 completedHandshake      time.Time
  56                 lastUsefulChunkReceived time.Time
  57                 lastChunkSent           time.Time
  58
  59                 // Stuff controlled by the local peer.
  60                 needRequestUpdate    string
  61                 requestState         request_strategy.PeerRequestState
  62                 updateRequestsTimer  *time.Timer
  63                 lastRequestUpdate    time.Time
  64                 peakRequests         maxRequests
  65                 lastBecameInterested time.Time
  66                 priorInterest        time.Duration
  67
  68                 lastStartedExpectingToReceiveChunks time.Time
  69                 cumulativeExpectedToReceiveChunks   time.Duration
  70                 _chunksReceivedWhileExpecting       int64
  71
  72                 choking                                bool
  73                 piecesReceivedSinceLastRequestUpdate   maxRequests
  74                 maxPiecesReceivedBetweenRequestUpdates maxRequests
  75                 // Chunks that we might reasonably expect to receive from the peer. Due to latency, buffering,
  76                 // and implementation differences, we may receive chunks that are no longer in the set of
  77                 // requests actually want. This could use a roaring.BSI if the memory use becomes noticeable.
  78                 validReceiveChunks map[RequestIndex]int
  79                 // Indexed by metadata piece, set to true if posted and pending a
  80                 // response.
  81                 metadataRequests []bool
  82                 sentHaves        bitmap.Bitmap
  83
  84                 // Stuff controlled by the remote peer.
  85                 peerInterested        bool
  86                 peerChoking           bool
  87                 peerRequests          map[Request]*peerRequestState
  88                 PeerPrefersEncryption bool // as indicated by 'e' field in extension handshake
  89                 PeerListenPort        int
  90                 // The highest possible number of pieces the torrent could have based on
  91                 // communication with the peer. Generally only useful until we have the
  92                 // torrent info.
  93                 peerMinPieces pieceIndex
  94                 // Pieces we've accepted chunks for from the peer.
  95                 peerTouchedPieces map[pieceIndex]struct{}
  96                 peerAllowedFast   typedRoaring.Bitmap[pieceIndex]
  97
  98                 PeerMaxRequests  maxRequests // Maximum pending requests the peer allows.
  99                 PeerExtensionIDs map[pp.ExtensionName]pp.ExtensionNumber
 100                 PeerClientName   atomic.Value
 101
 102                 logger log.Logger
 103         }
 104
 105         PeerSource string
 106
 107         peerRequestState struct {
 108                 data             []byte
 109                 allocReservation *alloclim.Reservation
 110         }
 111
 112         PeerRemoteAddr interface {
 113                 String() string
 114         }
 115
 116         peerRequests = orderedBitmap[RequestIndex]
 117 )
 118
 119 const (
 120         PeerSourceTracker         = "Tr"
 121         PeerSourceIncoming        = "I"
 122         PeerSourceDhtGetPeers     = "Hg" // Peers we found by searching a DHT.
 123         PeerSourceDhtAnnouncePeer = "Ha" // Peers that were announced to us by a DHT.
 124         PeerSourcePex             = "X"
 125         // The peer was given directly, such as through a magnet link.
 126         PeerSourceDirect = "M"
 127 )
 128
 129 func (p *Peer) initRequestState() {
 130         p.requestState.Requests = &peerRequests{}
 131 }
 132
 133 func (cn *Peer) updateExpectingChunks() {
 134         if cn.expectingChunks() {
 135                 if cn.lastStartedExpectingToReceiveChunks.IsZero() {
 136                         cn.lastStartedExpectingToReceiveChunks = time.Now()
 137                 }
 138         } else {
 139                 if !cn.lastStartedExpectingToReceiveChunks.IsZero() {
 140                         cn.cumulativeExpectedToReceiveChunks += time.Since(cn.lastStartedExpectingToReceiveChunks)
 141                         cn.lastStartedExpectingToReceiveChunks = time.Time{}
 142                 }
 143         }
 144 }
 145
 146 func (cn *Peer) expectingChunks() bool {
 147         if cn.requestState.Requests.IsEmpty() {
 148                 return false
 149         }
 150         if !cn.requestState.Interested {
 151                 return false
 152         }
 153         if !cn.peerChoking {
 154                 return true
 155         }
 156         haveAllowedFastRequests := false
 157         cn.peerAllowedFast.Iterate(func(i pieceIndex) bool {
 158                 haveAllowedFastRequests = roaringBitmapRangeCardinality[RequestIndex](
 159                         cn.requestState.Requests,
 160                         cn.t.pieceRequestIndexOffset(i),
 161                         cn.t.pieceRequestIndexOffset(i+1),
 162                 ) == 0
 163                 return !haveAllowedFastRequests
 164         })
 165         return haveAllowedFastRequests
 166 }
 167
 168 func (cn *Peer) remoteChokingPiece(piece pieceIndex) bool {
 169         return cn.peerChoking && !cn.peerAllowedFast.Contains(piece)
 170 }
 171
 172 func (cn *Peer) cumInterest() time.Duration {
 173         ret := cn.priorInterest
 174         if cn.requestState.Interested {
 175                 ret += time.Since(cn.lastBecameInterested)
 176         }
 177         return ret
 178 }
 179
 180 func (cn *Peer) locker() *lockWithDeferreds {
 181         return cn.t.cl.locker()
 182 }
 183
 184 func (cn *Peer) supportsExtension(ext pp.ExtensionName) bool {
 185         _, ok := cn.PeerExtensionIDs[ext]
 186         return ok
 187 }
 188
 189 // The best guess at number of pieces in the torrent for this peer.
 190 func (cn *Peer) bestPeerNumPieces() pieceIndex {
 191         if cn.t.haveInfo() {
 192                 return cn.t.numPieces()
 193         }
 194         return cn.peerMinPieces
 195 }
 196
 197 func (cn *Peer) completedString() string {
 198         have := pieceIndex(cn.peerPieces().GetCardinality())
 199         if all, _ := cn.peerHasAllPieces(); all {
 200                 have = cn.bestPeerNumPieces()
 201         }
 202         return fmt.Sprintf("%d/%d", have, cn.bestPeerNumPieces())
 203 }
 204
 205 func eventAgeString(t time.Time) string {
 206         if t.IsZero() {
 207                 return "never"
 208         }
 209         return fmt.Sprintf("%.2fs ago", time.Since(t).Seconds())
 210 }
 211
 212 // Inspired by https://github.com/transmission/transmission/wiki/Peer-Status-Text.
 213 func (cn *Peer) statusFlags() (ret string) {
 214         c := func(b byte) {
 215                 ret += string([]byte{b})
 216         }
 217         if cn.requestState.Interested {
 218                 c('i')
 219         }
 220         if cn.choking {
 221                 c('c')
 222         }
 223         c('-')
 224         ret += cn.connectionFlags()
 225         c('-')
 226         if cn.peerInterested {
 227                 c('i')
 228         }
 229         if cn.peerChoking {
 230                 c('c')
 231         }
 232         return
 233 }
 234
 235 func (cn *Peer) downloadRate() float64 {
 236         num := cn._stats.BytesReadUsefulData.Int64()
 237         if num == 0 {
 238                 return 0
 239         }
 240         return float64(num) / cn.totalExpectingTime().Seconds()
 241 }
 242
 243 func (cn *Peer) DownloadRate() float64 {
 244         cn.locker().RLock()
 245         defer cn.locker().RUnlock()
 246
 247         return cn.downloadRate()
 248 }
 249
 250 func (cn *Peer) iterContiguousPieceRequests(f func(piece pieceIndex, count int)) {
 251         var last Option[pieceIndex]
 252         var count int
 253         next := func(item Option[pieceIndex]) {
 254                 if item == last {
 255                         count++
 256                 } else {
 257                         if count != 0 {
 258                                 f(last.Value, count)
 259                         }
 260                         last = item
 261                         count = 1
 262                 }
 263         }
 264         cn.requestState.Requests.Iterate(func(requestIndex request_strategy.RequestIndex) bool {
 265                 next(Some(cn.t.pieceIndexOfRequestIndex(requestIndex)))
 266                 return true
 267         })
 268         next(None[pieceIndex]())
 269 }
 270
 271 func (cn *Peer) writeStatus(w io.Writer, t *Torrent) {
 272         // \t isn't preserved in <pre> blocks?
 273         if cn.closed.IsSet() {
 274                 fmt.Fprint(w, "CLOSED: ")
 275         }
 276         fmt.Fprintln(w, strings.Join(cn.peerImplStatusLines(), "\n"))
 277         prio, err := cn.peerPriority()
 278         prioStr := fmt.Sprintf("%08x", prio)
 279         if err != nil {
 280                 prioStr += ": " + err.Error()
 281         }
 282         fmt.Fprintf(w, "bep40-prio: %v\n", prioStr)
 283         fmt.Fprintf(w, "last msg: %s, connected: %s, last helpful: %s, itime: %s, etime: %s\n",
 284                 eventAgeString(cn.lastMessageReceived),
 285                 eventAgeString(cn.completedHandshake),
 286                 eventAgeString(cn.lastHelpful()),
 287                 cn.cumInterest(),
 288                 cn.totalExpectingTime(),
 289         )
 290         fmt.Fprintf(w,
 291                 "%s completed, %d pieces touched, good chunks: %v/%v:%v reqq: %d+%v/(%d/%d):%d/%d, flags: %s, dr: %.1f KiB/s\n",
 292                 cn.completedString(),
 293                 len(cn.peerTouchedPieces),
 294                 &cn._stats.ChunksReadUseful,
 295                 &cn._stats.ChunksRead,
 296                 &cn._stats.ChunksWritten,
 297                 cn.requestState.Requests.GetCardinality(),
 298                 cn.requestState.Cancelled.GetCardinality(),
 299                 cn.nominalMaxRequests(),
 300                 cn.PeerMaxRequests,
 301                 len(cn.peerRequests),
 302                 localClientReqq,
 303                 cn.statusFlags(),
 304                 cn.downloadRate()/(1<<10),
 305         )
 306         fmt.Fprintf(w, "requested pieces:")
 307         cn.iterContiguousPieceRequests(func(piece pieceIndex, count int) {
 308                 fmt.Fprintf(w, " %v(%v)", piece, count)
 309         })
 310         fmt.Fprintf(w, "\n")
 311 }
 312
 313 func (p *Peer) close() {
 314         if !p.closed.Set() {
 315                 return
 316         }
 317         if p.updateRequestsTimer != nil {
 318                 p.updateRequestsTimer.Stop()
 319         }
 320         p.peerImpl.onClose()
 321         if p.t != nil {
 322                 p.t.decPeerPieceAvailability(p)
 323         }
 324         for _, f := range p.callbacks.PeerClosed {
 325                 f(p)
 326         }
 327 }
 328
 329 // Peer definitely has a piece, for purposes of requesting. So it's not sufficient that we think
 330 // they do (known=true).
 331 func (cn *Peer) peerHasPiece(piece pieceIndex) bool {
 332         if all, known := cn.peerHasAllPieces(); all && known {
 333                 return true
 334         }
 335         return cn.peerPieces().ContainsInt(piece)
 336 }
 337
 338 // 64KiB, but temporarily less to work around an issue with WebRTC. TODO: Update when
 339 // https://github.com/pion/datachannel/issues/59 is fixed.
 340 const (
 341         writeBufferHighWaterLen = 1 << 15
 342         writeBufferLowWaterLen  = writeBufferHighWaterLen / 2
 343 )
 344
 345 var (
 346         interestedMsgLen = len(pp.Message{Type: pp.Interested}.MustMarshalBinary())
 347         requestMsgLen    = len(pp.Message{Type: pp.Request}.MustMarshalBinary())
 348         // This is the maximum request count that could fit in the write buffer if it's at or below the
 349         // low water mark when we run maybeUpdateActualRequestState.
 350         maxLocalToRemoteRequests = (writeBufferHighWaterLen - writeBufferLowWaterLen - interestedMsgLen) / requestMsgLen
 351 )
 352
 353 // The actual value to use as the maximum outbound requests.
 354 func (cn *Peer) nominalMaxRequests() maxRequests {
 355         return maxInt(1, minInt(cn.PeerMaxRequests, cn.peakRequests*2, maxLocalToRemoteRequests))
 356 }
 357
 358 func (cn *Peer) totalExpectingTime() (ret time.Duration) {
 359         ret = cn.cumulativeExpectedToReceiveChunks
 360         if !cn.lastStartedExpectingToReceiveChunks.IsZero() {
 361                 ret += time.Since(cn.lastStartedExpectingToReceiveChunks)
 362         }
 363         return
 364 }
 365
 366 func (cn *Peer) setInterested(interested bool) bool {
 367         if cn.requestState.Interested == interested {
 368                 return true
 369         }
 370         cn.requestState.Interested = interested
 371         if interested {
 372                 cn.lastBecameInterested = time.Now()
 373         } else if !cn.lastBecameInterested.IsZero() {
 374                 cn.priorInterest += time.Since(cn.lastBecameInterested)
 375         }
 376         cn.updateExpectingChunks()
 377         // log.Printf("%p: setting interest: %v", cn, interested)
 378         return cn.writeInterested(interested)
 379 }
 380
 381 // The function takes a message to be sent, and returns true if more messages
 382 // are okay.
 383 type messageWriter func(pp.Message) bool
 384
 385 // This function seems to only used by Peer.request. It's all logic checks, so maybe we can no-op it
 386 // when we want to go fast.
 387 func (cn *Peer) shouldRequest(r RequestIndex) error {
 388         err := cn.t.checkValidReceiveChunk(cn.t.requestIndexToRequest(r))
 389         if err != nil {
 390                 return err
 391         }
 392         pi := cn.t.pieceIndexOfRequestIndex(r)
 393         if cn.requestState.Cancelled.Contains(r) {
 394                 return errors.New("request is cancelled and waiting acknowledgement")
 395         }
 396         if !cn.peerHasPiece(pi) {
 397                 return errors.New("requesting piece peer doesn't have")
 398         }
 399         if !cn.t.peerIsActive(cn) {
 400                 panic("requesting but not in active conns")
 401         }
 402         if cn.closed.IsSet() {
 403                 panic("requesting when connection is closed")
 404         }
 405         if cn.t.hashingPiece(pi) {
 406                 panic("piece is being hashed")
 407         }
 408         if cn.t.pieceQueuedForHash(pi) {
 409                 panic("piece is queued for hash")
 410         }
 411         if cn.peerChoking && !cn.peerAllowedFast.Contains(pi) {
 412                 // This could occur if we made a request with the fast extension, and then got choked and
 413                 // haven't had the request rejected yet.
 414                 if !cn.requestState.Requests.Contains(r) {
 415                         panic("peer choking and piece not allowed fast")
 416                 }
 417         }
 418         return nil
 419 }
 420
 421 func (cn *Peer) mustRequest(r RequestIndex) bool {
 422         more, err := cn.request(r)
 423         if err != nil {
 424                 panic(err)
 425         }
 426         return more
 427 }
 428
 429 func (cn *Peer) request(r RequestIndex) (more bool, err error) {
 430         if err := cn.shouldRequest(r); err != nil {
 431                 panic(err)
 432         }
 433         if cn.requestState.Requests.Contains(r) {
 434                 return true, nil
 435         }
 436         if maxRequests(cn.requestState.Requests.GetCardinality()) >= cn.nominalMaxRequests() {
 437                 return true, errors.New("too many outstanding requests")
 438         }
 439         cn.requestState.Requests.Add(r)
 440         if cn.validReceiveChunks == nil {
 441                 cn.validReceiveChunks = make(map[RequestIndex]int)
 442         }
 443         cn.validReceiveChunks[r]++
 444         cn.t.requestState[r] = requestState{
 445                 peer: cn,
 446                 when: time.Now(),
 447         }
 448         cn.updateExpectingChunks()
 449         ppReq := cn.t.requestIndexToRequest(r)
 450         for _, f := range cn.callbacks.SentRequest {
 451                 f(PeerRequestEvent{cn, ppReq})
 452         }
 453         return cn.peerImpl._request(ppReq), nil
 454 }
 455
 456 func (me *Peer) cancel(r RequestIndex) {
 457         if !me.deleteRequest(r) {
 458                 panic("request not existing should have been guarded")
 459         }
 460         if me._cancel(r) {
 461                 if !me.requestState.Cancelled.CheckedAdd(r) {
 462                         panic("request already cancelled")
 463                 }
 464         }
 465         me.decPeakRequests()
 466         if me.isLowOnRequests() {
 467                 me.updateRequests("Peer.cancel")
 468         }
 469 }
 470
 471 // Sets a reason to update requests, and if there wasn't already one, handle it.
 472 func (cn *Peer) updateRequests(reason string) {
 473         if cn.needRequestUpdate != "" {
 474                 return
 475         }
 476         if reason != peerUpdateRequestsTimerReason && !cn.isLowOnRequests() {
 477                 return
 478         }
 479         cn.needRequestUpdate = reason
 480         cn.handleUpdateRequests()
 481 }
 482
 483 // Emits the indices in the Bitmaps bms in order, never repeating any index.
 484 // skip is mutated during execution, and its initial values will never be
 485 // emitted.
 486 func iterBitmapsDistinct(skip *bitmap.Bitmap, bms ...bitmap.Bitmap) iter.Func {
 487         return func(cb iter.Callback) {
 488                 for _, bm := range bms {
 489                         if !iter.All(
 490                                 func(_i interface{}) bool {
 491                                         i := _i.(int)
 492                                         if skip.Contains(bitmap.BitIndex(i)) {
 493                                                 return true
 494                                         }
 495                                         skip.Add(bitmap.BitIndex(i))
 496                                         return cb(i)
 497                                 },
 498                                 bm.Iter,
 499                         ) {
 500                                 return
 501                         }
 502                 }
 503         }
 504 }
 505
 506 func (cn *Peer) peerPiecesChanged() {
 507         cn.t.maybeDropMutuallyCompletePeer(cn)
 508 }
 509
 510 // After handshake, we know what Torrent and Client stats to include for a
 511 // connection.
 512 func (cn *Peer) postHandshakeStats(f func(*ConnStats)) {
 513         t := cn.t
 514         f(&t.stats)
 515         f(&t.cl.stats)
 516 }
 517
 518 // All ConnStats that include this connection. Some objects are not known
 519 // until the handshake is complete, after which it's expected to reconcile the
 520 // differences.
 521 func (cn *Peer) allStats(f func(*ConnStats)) {
 522         f(&cn._stats)
 523         if cn.reconciledHandshakeStats {
 524                 cn.postHandshakeStats(f)
 525         }
 526 }
 527
 528 func (cn *Peer) readBytes(n int64) {
 529         cn.allStats(add(n, func(cs *ConnStats) *Count { return &cs.BytesRead }))
 530 }
 531
 532 // Returns whether the connection could be useful to us. We're seeding and
 533 // they want data, we don't have metainfo and they can provide it, etc.
 534 func (c *Peer) useful() bool {
 535         t := c.t
 536         if c.closed.IsSet() {
 537                 return false
 538         }
 539         if !t.haveInfo() {
 540                 return c.supportsExtension("ut_metadata")
 541         }
 542         if t.seeding() && c.peerInterested {
 543                 return true
 544         }
 545         if c.peerHasWantedPieces() {
 546                 return true
 547         }
 548         return false
 549 }
 550
 551 func (c *Peer) lastHelpful() (ret time.Time) {
 552         ret = c.lastUsefulChunkReceived
 553         if c.t.seeding() && c.lastChunkSent.After(ret) {
 554                 ret = c.lastChunkSent
 555         }
 556         return
 557 }
 558
 559 // Returns whether any part of the chunk would lie outside a piece of the given length.
 560 func chunkOverflowsPiece(cs ChunkSpec, pieceLength pp.Integer) bool {
 561         switch {
 562         default:
 563                 return false
 564         case cs.Begin+cs.Length > pieceLength:
 565         // Check for integer overflow
 566         case cs.Begin > pp.IntegerMax-cs.Length:
 567         }
 568         return true
 569 }
 570
 571 func runSafeExtraneous(f func()) {
 572         if true {
 573                 go f()
 574         } else {
 575                 f()
 576         }
 577 }
 578
 579 // Returns true if it was valid to reject the request.
 580 func (c *Peer) remoteRejectedRequest(r RequestIndex) bool {
 581         if c.deleteRequest(r) {
 582                 c.decPeakRequests()
 583         } else if !c.requestState.Cancelled.CheckedRemove(r) {
 584                 return false
 585         }
 586         if c.isLowOnRequests() {
 587                 c.updateRequests("Peer.remoteRejectedRequest")
 588         }
 589         c.decExpectedChunkReceive(r)
 590         return true
 591 }
 592
 593 func (c *Peer) decExpectedChunkReceive(r RequestIndex) {
 594         count := c.validReceiveChunks[r]
 595         if count == 1 {
 596                 delete(c.validReceiveChunks, r)
 597         } else if count > 1 {
 598                 c.validReceiveChunks[r] = count - 1
 599         } else {
 600                 panic(r)
 601         }
 602 }
 603
 604 func (c *Peer) doChunkReadStats(size int64) {
 605         c.allStats(func(cs *ConnStats) { cs.receivedChunk(size) })
 606 }
 607
 608 // Handle a received chunk from a peer.
 609 func (c *Peer) receiveChunk(msg *pp.Message) error {
 610         chunksReceived.Add("total", 1)
 611
 612         ppReq := newRequestFromMessage(msg)
 613         t := c.t
 614         err := t.checkValidReceiveChunk(ppReq)
 615         if err != nil {
 616                 err = log.WithLevel(log.Warning, err)
 617                 return err
 618         }
 619         req := c.t.requestIndexFromRequest(ppReq)
 620
 621         if c.bannableAddr.Ok {
 622                 t.smartBanCache.RecordBlock(c.bannableAddr.Value, req, msg.Piece)
 623         }
 624
 625         if c.peerChoking {
 626                 chunksReceived.Add("while choked", 1)
 627         }
 628
 629         if c.validReceiveChunks[req] <= 0 {
 630                 chunksReceived.Add("unexpected", 1)
 631                 return errors.New("received unexpected chunk")
 632         }
 633         c.decExpectedChunkReceive(req)
 634
 635         if c.peerChoking && c.peerAllowedFast.Contains(pieceIndex(ppReq.Index)) {
 636                 chunksReceived.Add("due to allowed fast", 1)
 637         }
 638
 639         // The request needs to be deleted immediately to prevent cancels occurring asynchronously when
 640         // have actually already received the piece, while we have the Client unlocked to write the data
 641         // out.
 642         intended := false
 643         {
 644                 if c.requestState.Requests.Contains(req) {
 645                         for _, f := range c.callbacks.ReceivedRequested {
 646                                 f(PeerMessageEvent{c, msg})
 647                         }
 648                 }
 649                 // Request has been satisfied.
 650                 if c.deleteRequest(req) || c.requestState.Cancelled.CheckedRemove(req) {
 651                         intended = true
 652                         if !c.peerChoking {
 653                                 c._chunksReceivedWhileExpecting++
 654                         }
 655                         if c.isLowOnRequests() {
 656                                 c.updateRequests("Peer.receiveChunk deleted request")
 657                         }
 658                 } else {
 659                         chunksReceived.Add("unintended", 1)
 660                 }
 661         }
 662
 663         cl := t.cl
 664
 665         // Do we actually want this chunk?
 666         if t.haveChunk(ppReq) {
 667                 // panic(fmt.Sprintf("%+v", ppReq))
 668                 chunksReceived.Add("redundant", 1)
 669                 c.allStats(add(1, func(cs *ConnStats) *Count { return &cs.ChunksReadWasted }))
 670                 return nil
 671         }
 672
 673         piece := &t.pieces[ppReq.Index]
 674
 675         c.allStats(add(1, func(cs *ConnStats) *Count { return &cs.ChunksReadUseful }))
 676         c.allStats(add(int64(len(msg.Piece)), func(cs *ConnStats) *Count { return &cs.BytesReadUsefulData }))
 677         if intended {
 678                 c.piecesReceivedSinceLastRequestUpdate++
 679                 c.allStats(add(int64(len(msg.Piece)), func(cs *ConnStats) *Count { return &cs.BytesReadUsefulIntendedData }))
 680         }
 681         for _, f := range c.t.cl.config.Callbacks.ReceivedUsefulData {
 682                 f(ReceivedUsefulDataEvent{c, msg})
 683         }
 684         c.lastUsefulChunkReceived = time.Now()
 685
 686         // Need to record that it hasn't been written yet, before we attempt to do
 687         // anything with it.
 688         piece.incrementPendingWrites()
 689         // Record that we have the chunk, so we aren't trying to download it while
 690         // waiting for it to be written to storage.
 691         piece.unpendChunkIndex(chunkIndexFromChunkSpec(ppReq.ChunkSpec, t.chunkSize))
 692
 693         // Cancel pending requests for this chunk from *other* peers.
 694         if p := t.requestingPeer(req); p != nil {
 695                 if p == c {
 696                         panic("should not be pending request from conn that just received it")
 697                 }
 698                 p.cancel(req)
 699         }
 700
 701         err = func() error {
 702                 cl.unlock()
 703                 defer cl.lock()
 704                 concurrentChunkWrites.Add(1)
 705                 defer concurrentChunkWrites.Add(-1)
 706                 // Write the chunk out. Note that the upper bound on chunk writing concurrency will be the
 707                 // number of connections. We write inline with receiving the chunk (with this lock dance),
 708                 // because we want to handle errors synchronously and I haven't thought of a nice way to
 709                 // defer any concurrency to the storage and have that notify the client of errors. TODO: Do
 710                 // that instead.
 711                 return t.writeChunk(int(msg.Index), int64(msg.Begin), msg.Piece)
 712         }()
 713
 714         piece.decrementPendingWrites()
 715
 716         if err != nil {
 717                 c.logger.WithDefaultLevel(log.Error).Printf("writing received chunk %v: %v", req, err)
 718                 t.pendRequest(req)
 719                 // Necessary to pass TestReceiveChunkStorageFailureSeederFastExtensionDisabled. I think a
 720                 // request update runs while we're writing the chunk that just failed. Then we never do a
 721                 // fresh update after pending the failed request.
 722                 c.updateRequests("Peer.receiveChunk error writing chunk")
 723                 t.onWriteChunkErr(err)
 724                 return nil
 725         }
 726
 727         c.onDirtiedPiece(pieceIndex(ppReq.Index))
 728
 729         // We need to ensure the piece is only queued once, so only the last chunk writer gets this job.
 730         if t.pieceAllDirty(pieceIndex(ppReq.Index)) && piece.pendingWrites == 0 {
 731                 t.queuePieceCheck(pieceIndex(ppReq.Index))
 732                 // We don't pend all chunks here anymore because we don't want code dependent on the dirty
 733                 // chunk status (such as the haveChunk call above) to have to check all the various other
 734                 // piece states like queued for hash, hashing etc. This does mean that we need to be sure
 735                 // that chunk pieces are pended at an appropriate time later however.
 736         }
 737
 738         cl.event.Broadcast()
 739         // We do this because we've written a chunk, and may change PieceState.Partial.
 740         t.publishPieceChange(pieceIndex(ppReq.Index))
 741
 742         return nil
 743 }
 744
 745 func (c *Peer) onDirtiedPiece(piece pieceIndex) {
 746         if c.peerTouchedPieces == nil {
 747                 c.peerTouchedPieces = make(map[pieceIndex]struct{})
 748         }
 749         c.peerTouchedPieces[piece] = struct{}{}
 750         ds := &c.t.pieces[piece].dirtiers
 751         if *ds == nil {
 752                 *ds = make(map[*Peer]struct{})
 753         }
 754         (*ds)[c] = struct{}{}
 755 }
 756
 757 func (cn *Peer) netGoodPiecesDirtied() int64 {
 758         return cn._stats.PiecesDirtiedGood.Int64() - cn._stats.PiecesDirtiedBad.Int64()
 759 }
 760
 761 func (c *Peer) peerHasWantedPieces() bool {
 762         if all, _ := c.peerHasAllPieces(); all {
 763                 return !c.t.haveAllPieces() && !c.t._pendingPieces.IsEmpty()
 764         }
 765         if !c.t.haveInfo() {
 766                 return !c.peerPieces().IsEmpty()
 767         }
 768         return c.peerPieces().Intersects(&c.t._pendingPieces)
 769 }
 770
 771 // Returns true if an outstanding request is removed. Cancelled requests should be handled
 772 // separately.
 773 func (c *Peer) deleteRequest(r RequestIndex) bool {
 774         if !c.requestState.Requests.CheckedRemove(r) {
 775                 return false
 776         }
 777         for _, f := range c.callbacks.DeletedRequest {
 778                 f(PeerRequestEvent{c, c.t.requestIndexToRequest(r)})
 779         }
 780         c.updateExpectingChunks()
 781         if c.t.requestingPeer(r) != c {
 782                 panic("only one peer should have a given request at a time")
 783         }
 784         delete(c.t.requestState, r)
 785         // c.t.iterPeers(func(p *Peer) {
 786         //      if p.isLowOnRequests() {
 787         //              p.updateRequests("Peer.deleteRequest")
 788         //      }
 789         // })
 790         return true
 791 }
 792
 793 func (c *Peer) deleteAllRequests(reason string) {
 794         if c.requestState.Requests.IsEmpty() {
 795                 return
 796         }
 797         c.requestState.Requests.IterateSnapshot(func(x RequestIndex) bool {
 798                 if !c.deleteRequest(x) {
 799                         panic("request should exist")
 800                 }
 801                 return true
 802         })
 803         c.assertNoRequests()
 804         c.t.iterPeers(func(p *Peer) {
 805                 if p.isLowOnRequests() {
 806                         p.updateRequests(reason)
 807                 }
 808         })
 809         return
 810 }
 811
 812 func (c *Peer) assertNoRequests() {
 813         if !c.requestState.Requests.IsEmpty() {
 814                 panic(c.requestState.Requests.GetCardinality())
 815         }
 816 }
 817
 818 func (c *Peer) cancelAllRequests() {
 819         c.requestState.Requests.IterateSnapshot(func(x RequestIndex) bool {
 820                 c.cancel(x)
 821                 return true
 822         })
 823         c.assertNoRequests()
 824         return
 825 }
 826
 827 func (c *Peer) peerPriority() (peerPriority, error) {
 828         return bep40Priority(c.remoteIpPort(), c.localPublicAddr)
 829 }
 830
 831 func (c *Peer) remoteIp() net.IP {
 832         host, _, _ := net.SplitHostPort(c.RemoteAddr.String())
 833         return net.ParseIP(host)
 834 }
 835
 836 func (c *Peer) remoteIpPort() IpPort {
 837         ipa, _ := tryIpPortFromNetAddr(c.RemoteAddr)
 838         return IpPort{ipa.IP, uint16(ipa.Port)}
 839 }
 840
 841 func (c *Peer) trust() connectionTrust {
 842         return connectionTrust{c.trusted, c.netGoodPiecesDirtied()}
 843 }
 844
 845 type connectionTrust struct {
 846         Implicit            bool
 847         NetGoodPiecesDirted int64
 848 }
 849
 850 func (l connectionTrust) Less(r connectionTrust) bool {
 851         return multiless.New().Bool(l.Implicit, r.Implicit).Int64(l.NetGoodPiecesDirted, r.NetGoodPiecesDirted).Less()
 852 }
 853
 854 // Returns a new Bitmap that includes bits for all pieces the peer could have based on their claims.
 855 func (cn *Peer) newPeerPieces() *roaring.Bitmap {
 856         // TODO: Can we use copy on write?
 857         ret := cn.peerPieces().Clone()
 858         if all, _ := cn.peerHasAllPieces(); all {
 859                 if cn.t.haveInfo() {
 860                         ret.AddRange(0, bitmap.BitRange(cn.t.numPieces()))
 861                 } else {
 862                         ret.AddRange(0, bitmap.ToEnd)
 863                 }
 864         }
 865         return ret
 866 }
 867
 868 func (cn *Peer) stats() *ConnStats {
 869         return &cn._stats
 870 }
 871
 872 func (p *Peer) TryAsPeerConn() (*PeerConn, bool) {
 873         pc, ok := p.peerImpl.(*PeerConn)
 874         return pc, ok
 875 }
 876
 877 func (p *Peer) uncancelledRequests() uint64 {
 878         return p.requestState.Requests.GetCardinality()
 879 }
 880
 881 type peerLocalPublicAddr = IpPort
 882
 883 func (p *Peer) isLowOnRequests() bool {
 884         return p.requestState.Requests.IsEmpty() && p.requestState.Cancelled.IsEmpty()
 885 }
 886
 887 func (p *Peer) decPeakRequests() {
 888         // // This can occur when peak requests are altered by the update request timer to be lower than
 889         // // the actual number of outstanding requests. Let's let it go negative and see what happens. I
 890         // // wonder what happens if maxRequests is not signed.
 891         // if p.peakRequests < 1 {
 892         //      panic(p.peakRequests)
 893         // }
 894         p.peakRequests--
 895 }