requesting.go

   1 package torrent
   2
   3 import (
   4         "container/heap"
   5         "context"
   6         "encoding/gob"
   7         "reflect"
   8         "runtime/pprof"
   9         "time"
  10         "unsafe"
  11
  12         "github.com/anacrolix/log"
  13         "github.com/anacrolix/multiless"
  14
  15         request_strategy "github.com/anacrolix/torrent/request-strategy"
  16 )
  17
  18 func (cl *Client) tickleRequester() {
  19         cl.updateRequests.Broadcast()
  20 }
  21
  22 func (cl *Client) getRequestStrategyInput() request_strategy.Input {
  23         ts := make([]request_strategy.Torrent, 0, len(cl.torrents))
  24         for _, t := range cl.torrents {
  25                 if !t.haveInfo() {
  26                         // This would be removed if metadata is handled here. We have to guard against not
  27                         // knowing the piece size. If we have no info, we have no pieces too, so the end result
  28                         // is the same.
  29                         continue
  30                 }
  31                 rst := request_strategy.Torrent{
  32                         InfoHash:       t.infoHash,
  33                         ChunksPerPiece: t.chunksPerRegularPiece(),
  34                 }
  35                 if t.storage != nil {
  36                         rst.Capacity = t.storage.Capacity
  37                 }
  38                 rst.Pieces = make([]request_strategy.Piece, 0, len(t.pieces))
  39                 for i := range t.pieces {
  40                         p := &t.pieces[i]
  41                         rst.Pieces = append(rst.Pieces, request_strategy.Piece{
  42                                 Request:           !t.ignorePieceForRequests(i),
  43                                 Priority:          p.purePriority(),
  44                                 Partial:           t.piecePartiallyDownloaded(i),
  45                                 Availability:      p.availability,
  46                                 Length:            int64(p.length()),
  47                                 NumPendingChunks:  int(t.pieceNumPendingChunks(i)),
  48                                 IterPendingChunks: &p.undirtiedChunksIter,
  49                         })
  50                 }
  51                 t.iterPeers(func(p *Peer) {
  52                         if p.closed.IsSet() {
  53                                 return
  54                         }
  55                         if p.piecesReceivedSinceLastRequestUpdate > p.maxPiecesReceivedBetweenRequestUpdates {
  56                                 p.maxPiecesReceivedBetweenRequestUpdates = p.piecesReceivedSinceLastRequestUpdate
  57                         }
  58                         p.piecesReceivedSinceLastRequestUpdate = 0
  59                         rst.Peers = append(rst.Peers, request_strategy.Peer{
  60                                 Pieces:           *p.newPeerPieces(),
  61                                 MaxRequests:      p.nominalMaxRequests(),
  62                                 ExistingRequests: p.actualRequestState.Requests,
  63                                 Choking:          p.peerChoking,
  64                                 PieceAllowedFast: p.peerAllowedFast,
  65                                 DownloadRate:     p.downloadRate(),
  66                                 Age:              time.Since(p.completedHandshake),
  67                                 Id: peerId{
  68                                         Peer: p,
  69                                         ptr:  uintptr(unsafe.Pointer(p)),
  70                                 },
  71                         })
  72                 })
  73                 ts = append(ts, rst)
  74         }
  75         return request_strategy.Input{
  76                 Torrents:           ts,
  77                 MaxUnverifiedBytes: cl.config.MaxUnverifiedBytes,
  78         }
  79 }
  80
  81 func init() {
  82         gob.Register(peerId{})
  83 }
  84
  85 type peerId struct {
  86         *Peer
  87         ptr uintptr
  88 }
  89
  90 func (p peerId) Uintptr() uintptr {
  91         return p.ptr
  92 }
  93
  94 func (p peerId) GobEncode() (b []byte, _ error) {
  95         *(*reflect.SliceHeader)(unsafe.Pointer(&b)) = reflect.SliceHeader{
  96                 Data: uintptr(unsafe.Pointer(&p.ptr)),
  97                 Len:  int(unsafe.Sizeof(p.ptr)),
  98                 Cap:  int(unsafe.Sizeof(p.ptr)),
  99         }
 100         return
 101 }
 102
 103 func (p *peerId) GobDecode(b []byte) error {
 104         if uintptr(len(b)) != unsafe.Sizeof(p.ptr) {
 105                 panic(len(b))
 106         }
 107         ptr := unsafe.Pointer(&b[0])
 108         p.ptr = *(*uintptr)(ptr)
 109         log.Printf("%p", ptr)
 110         dst := reflect.SliceHeader{
 111                 Data: uintptr(unsafe.Pointer(&p.Peer)),
 112                 Len:  int(unsafe.Sizeof(p.Peer)),
 113                 Cap:  int(unsafe.Sizeof(p.Peer)),
 114         }
 115         copy(*(*[]byte)(unsafe.Pointer(&dst)), b)
 116         return nil
 117 }
 118
 119 type (
 120         RequestIndex   = request_strategy.RequestIndex
 121         chunkIndexType = request_strategy.ChunkIndex
 122 )
 123
 124 type peerRequests struct {
 125         requestIndexes       []RequestIndex
 126         peer                 *Peer
 127         torrentStrategyInput request_strategy.Torrent
 128 }
 129
 130 func (p *peerRequests) Len() int {
 131         return len(p.requestIndexes)
 132 }
 133
 134 func (p *peerRequests) Less(i, j int) bool {
 135         leftRequest := p.requestIndexes[i]
 136         rightRequest := p.requestIndexes[j]
 137         t := p.peer.t
 138         leftPieceIndex := leftRequest / p.torrentStrategyInput.ChunksPerPiece
 139         rightPieceIndex := rightRequest / p.torrentStrategyInput.ChunksPerPiece
 140         leftCurrent := p.peer.actualRequestState.Requests.Contains(leftRequest)
 141         rightCurrent := p.peer.actualRequestState.Requests.Contains(rightRequest)
 142         pending := func(index RequestIndex, current bool) int {
 143                 ret := t.pendingRequests.Get(index)
 144                 if current {
 145                         ret--
 146                 }
 147                 // See https://github.com/anacrolix/torrent/issues/679 for possible issues. This should be
 148                 // resolved.
 149                 if ret < 0 {
 150                         panic(ret)
 151                 }
 152                 return ret
 153         }
 154         ml := multiless.New()
 155         // Push requests that can't be served right now to the end. But we don't throw them away unless
 156         // there's a better alternative. This is for when we're using the fast extension and get choked
 157         // but our requests could still be good when we get unchoked.
 158         if p.peer.peerChoking {
 159                 ml = ml.Bool(
 160                         !p.peer.peerAllowedFast.Contains(leftPieceIndex),
 161                         !p.peer.peerAllowedFast.Contains(rightPieceIndex),
 162                 )
 163         }
 164         ml = ml.Int(
 165                 pending(leftRequest, leftCurrent),
 166                 pending(rightRequest, rightCurrent))
 167         ml = ml.Bool(!leftCurrent, !rightCurrent)
 168         ml = ml.Int(
 169                 -int(p.torrentStrategyInput.Pieces[leftPieceIndex].Priority),
 170                 -int(p.torrentStrategyInput.Pieces[rightPieceIndex].Priority),
 171         )
 172         ml = ml.Int(
 173                 int(p.torrentStrategyInput.Pieces[leftPieceIndex].Availability),
 174                 int(p.torrentStrategyInput.Pieces[rightPieceIndex].Availability))
 175         ml = ml.Uint32(leftPieceIndex, rightPieceIndex)
 176         ml = ml.Uint32(leftRequest, rightRequest)
 177         return ml.MustLess()
 178 }
 179
 180 func (p *peerRequests) Swap(i, j int) {
 181         p.requestIndexes[i], p.requestIndexes[j] = p.requestIndexes[j], p.requestIndexes[i]
 182 }
 183
 184 func (p *peerRequests) Push(x interface{}) {
 185         p.requestIndexes = append(p.requestIndexes, x.(RequestIndex))
 186 }
 187
 188 func (p *peerRequests) Pop() interface{} {
 189         last := len(p.requestIndexes) - 1
 190         x := p.requestIndexes[last]
 191         p.requestIndexes = p.requestIndexes[:last]
 192         return x
 193 }
 194
 195 type desiredRequestState struct {
 196         Requests   []RequestIndex
 197         Interested bool
 198 }
 199
 200 func (p *Peer) getDesiredRequestState() (desired desiredRequestState) {
 201         input := p.t.cl.getRequestStrategyInput()
 202         requestHeap := peerRequests{
 203                 peer: p,
 204         }
 205         for _, t := range input.Torrents {
 206                 if t.InfoHash == p.t.infoHash {
 207                         requestHeap.torrentStrategyInput = t
 208                         break
 209                 }
 210         }
 211         request_strategy.GetRequestablePieces(
 212                 input,
 213                 func(t *request_strategy.Torrent, rsp *request_strategy.Piece, pieceIndex int) {
 214                         if t.InfoHash != p.t.infoHash {
 215                                 return
 216                         }
 217                         if !p.peerHasPiece(pieceIndex) {
 218                                 return
 219                         }
 220                         allowedFast := p.peerAllowedFast.ContainsInt(pieceIndex)
 221                         rsp.IterPendingChunks.Iter(func(ci request_strategy.ChunkIndex) {
 222                                 r := p.t.pieceRequestIndexOffset(pieceIndex) + ci
 223                                 //if p.t.pendingRequests.Get(r) != 0 && !p.actualRequestState.Requests.Contains(r) {
 224                                 //      return
 225                                 //}
 226                                 if !allowedFast {
 227                                         // We must signal interest to request this
 228                                         desired.Interested = true
 229                                         // We can make or will allow sustaining a request here if we're not choked, or
 230                                         // have made the request previously (presumably while unchoked), and haven't had
 231                                         // the peer respond yet (and the request was retained because we are using the
 232                                         // fast extension).
 233                                         if p.peerChoking && !p.actualRequestState.Requests.Contains(r) {
 234                                                 // We can't request this right now.
 235                                                 return
 236                                         }
 237                                 }
 238                                 requestHeap.requestIndexes = append(requestHeap.requestIndexes, r)
 239                         })
 240                 },
 241         )
 242         p.t.assertPendingRequests()
 243         heap.Init(&requestHeap)
 244         for requestHeap.Len() != 0 && len(desired.Requests) < p.nominalMaxRequests() {
 245                 requestIndex := heap.Pop(&requestHeap).(RequestIndex)
 246                 desired.Requests = append(desired.Requests, requestIndex)
 247         }
 248         return
 249 }
 250
 251 func (p *Peer) maybeUpdateActualRequestState() bool {
 252         if p.needRequestUpdate == "" {
 253                 return true
 254         }
 255         var more bool
 256         pprof.Do(
 257                 context.Background(),
 258                 pprof.Labels("update request", p.needRequestUpdate),
 259                 func(_ context.Context) {
 260                         next := p.getDesiredRequestState()
 261                         more = p.applyRequestState(next)
 262                 },
 263         )
 264         return more
 265 }
 266
 267 // Transmit/action the request state to the peer.
 268 func (p *Peer) applyRequestState(next desiredRequestState) bool {
 269         current := &p.actualRequestState
 270         if !p.setInterested(next.Interested) {
 271                 return false
 272         }
 273         more := true
 274         cancel := current.Requests.Clone()
 275         for _, ri := range next.Requests {
 276                 cancel.Remove(ri)
 277         }
 278         cancel.Iterate(func(req uint32) bool {
 279                 more = p.cancel(req)
 280                 return more
 281         })
 282         if !more {
 283                 return false
 284         }
 285         for _, req := range next.Requests {
 286                 if p.cancelledRequests.Contains(req) {
 287                         // Waiting for a reject or piece message, which will suitably trigger us to update our
 288                         // requests, so we can skip this one with no additional consideration.
 289                         continue
 290                 }
 291                 // The cardinality of our desired requests shouldn't exceed the max requests since it's used
 292                 // in the calculation of the requests. However, if we cancelled requests and they haven't
 293                 // been rejected or serviced yet with the fast extension enabled, we can end up with more
 294                 // extra outstanding requests. We could subtract the number of outstanding cancels from the
 295                 // next request cardinality, but peers might not like that.
 296                 if maxRequests(current.Requests.GetCardinality()) >= p.nominalMaxRequests() {
 297                         //log.Printf("not assigning all requests [desired=%v, cancelled=%v, current=%v, max=%v]",
 298                         //      next.Requests.GetCardinality(),
 299                         //      p.cancelledRequests.GetCardinality(),
 300                         //      current.Requests.GetCardinality(),
 301                         //      p.nominalMaxRequests(),
 302                         //)
 303                         break
 304                 }
 305                 more = p.mustRequest(req)
 306                 if !more {
 307                         break
 308                 }
 309         }
 310         p.updateRequestsTimer.Stop()
 311         if more {
 312                 p.needRequestUpdate = ""
 313                 if !current.Requests.IsEmpty() {
 314                         p.updateRequestsTimer.Reset(3 * time.Second)
 315                 }
 316         }
 317         return more
 318 }