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/RoaringBitmap/roaring"
  13         "github.com/anacrolix/log"
  14         "github.com/anacrolix/multiless"
  15
  16         request_strategy "github.com/anacrolix/torrent/request-strategy"
  17 )
  18
  19 func (cl *Client) tickleRequester() {
  20         cl.updateRequests.Broadcast()
  21 }
  22
  23 func (cl *Client) getRequestStrategyInput() request_strategy.Input {
  24         ts := make([]request_strategy.Torrent, 0, len(cl.torrents))
  25         for _, t := range cl.torrents {
  26                 if !t.haveInfo() {
  27                         // This would be removed if metadata is handled here. We have to guard against not
  28                         // knowing the piece size. If we have no info, we have no pieces too, so the end result
  29                         // is the same.
  30                         continue
  31                 }
  32                 rst := request_strategy.Torrent{
  33                         InfoHash:       t.infoHash,
  34                         ChunksPerPiece: t.chunksPerRegularPiece(),
  35                 }
  36                 if t.storage != nil {
  37                         rst.Capacity = t.storage.Capacity
  38                 }
  39                 rst.Pieces = make([]request_strategy.Piece, 0, len(t.pieces))
  40                 for i := range t.pieces {
  41                         p := &t.pieces[i]
  42                         rst.Pieces = append(rst.Pieces, request_strategy.Piece{
  43                                 Request:           !t.ignorePieceForRequests(i),
  44                                 Priority:          p.purePriority(),
  45                                 Partial:           t.piecePartiallyDownloaded(i),
  46                                 Availability:      p.availability,
  47                                 Length:            int64(p.length()),
  48                                 NumPendingChunks:  int(t.pieceNumPendingChunks(i)),
  49                                 IterPendingChunks: &p.undirtiedChunksIter,
  50                         })
  51                 }
  52                 t.iterPeers(func(p *Peer) {
  53                         if p.closed.IsSet() {
  54                                 return
  55                         }
  56                         if p.piecesReceivedSinceLastRequestUpdate > p.maxPiecesReceivedBetweenRequestUpdates {
  57                                 p.maxPiecesReceivedBetweenRequestUpdates = p.piecesReceivedSinceLastRequestUpdate
  58                         }
  59                         p.piecesReceivedSinceLastRequestUpdate = 0
  60                         rst.Peers = append(rst.Peers, request_strategy.Peer{
  61                                 Pieces:           *p.newPeerPieces(),
  62                                 MaxRequests:      p.nominalMaxRequests(),
  63                                 ExistingRequests: p.actualRequestState.Requests,
  64                                 Choking:          p.peerChoking,
  65                                 PieceAllowedFast: p.peerAllowedFast,
  66                                 DownloadRate:     p.downloadRate(),
  67                                 Age:              time.Since(p.completedHandshake),
  68                                 Id: peerId{
  69                                         Peer: p,
  70                                         ptr:  uintptr(unsafe.Pointer(p)),
  71                                 },
  72                         })
  73                 })
  74                 ts = append(ts, rst)
  75         }
  76         return request_strategy.Input{
  77                 Torrents:           ts,
  78                 MaxUnverifiedBytes: cl.config.MaxUnverifiedBytes,
  79         }
  80 }
  81
  82 func init() {
  83         gob.Register(peerId{})
  84 }
  85
  86 type peerId struct {
  87         *Peer
  88         ptr uintptr
  89 }
  90
  91 func (p peerId) Uintptr() uintptr {
  92         return p.ptr
  93 }
  94
  95 func (p peerId) GobEncode() (b []byte, _ error) {
  96         *(*reflect.SliceHeader)(unsafe.Pointer(&b)) = reflect.SliceHeader{
  97                 Data: uintptr(unsafe.Pointer(&p.ptr)),
  98                 Len:  int(unsafe.Sizeof(p.ptr)),
  99                 Cap:  int(unsafe.Sizeof(p.ptr)),
 100         }
 101         return
 102 }
 103
 104 func (p *peerId) GobDecode(b []byte) error {
 105         if uintptr(len(b)) != unsafe.Sizeof(p.ptr) {
 106                 panic(len(b))
 107         }
 108         ptr := unsafe.Pointer(&b[0])
 109         p.ptr = *(*uintptr)(ptr)
 110         log.Printf("%p", ptr)
 111         dst := reflect.SliceHeader{
 112                 Data: uintptr(unsafe.Pointer(&p.Peer)),
 113                 Len:  int(unsafe.Sizeof(p.Peer)),
 114                 Cap:  int(unsafe.Sizeof(p.Peer)),
 115         }
 116         copy(*(*[]byte)(unsafe.Pointer(&dst)), b)
 117         return nil
 118 }
 119
 120 type RequestIndex = request_strategy.RequestIndex
 121 type chunkIndexType = request_strategy.ChunkIndex
 122
 123 type peerRequests struct {
 124         requestIndexes       []RequestIndex
 125         peer                 *Peer
 126         torrentStrategyInput request_strategy.Torrent
 127 }
 128
 129 func (p *peerRequests) Len() int {
 130         return len(p.requestIndexes)
 131 }
 132
 133 func (p *peerRequests) Less(i, j int) bool {
 134         leftRequest := p.requestIndexes[i]
 135         rightRequest := p.requestIndexes[j]
 136         t := p.peer.t
 137         leftPieceIndex := leftRequest / p.torrentStrategyInput.ChunksPerPiece
 138         rightPieceIndex := rightRequest / p.torrentStrategyInput.ChunksPerPiece
 139         leftCurrent := p.peer.actualRequestState.Requests.Contains(leftRequest)
 140         rightCurrent := p.peer.actualRequestState.Requests.Contains(rightRequest)
 141         pending := func(index RequestIndex, current bool) int {
 142                 ret := t.pendingRequests.Get(index)
 143                 if current {
 144                         ret--
 145                 }
 146                 // I have a hunch that this could trigger for requests for chunks that are choked and not
 147                 // allowed fast, since the current conn shouldn't already be included. It's a very specific
 148                 // circumstance, and if it triggers I will fix it.
 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 func (p *Peer) getDesiredRequestState() (desired requestState) {
 196         input := p.t.cl.getRequestStrategyInput()
 197         requestHeap := peerRequests{
 198                 peer: p,
 199         }
 200         for _, t := range input.Torrents {
 201                 if t.InfoHash == p.t.infoHash {
 202                         requestHeap.torrentStrategyInput = t
 203                         break
 204                 }
 205         }
 206         request_strategy.GetRequestablePieces(
 207                 input,
 208                 func(t *request_strategy.Torrent, rsp *request_strategy.Piece, pieceIndex int) {
 209                         if t.InfoHash != p.t.infoHash {
 210                                 return
 211                         }
 212                         if !p.peerHasPiece(pieceIndex) {
 213                                 return
 214                         }
 215                         allowedFast := p.peerAllowedFast.ContainsInt(pieceIndex)
 216                         rsp.IterPendingChunks.Iter(func(ci request_strategy.ChunkIndex) {
 217                                 if !allowedFast {
 218                                         // We must signal interest to request this..
 219                                         desired.Interested = true
 220                                         if p.peerChoking && !p.actualRequestState.Requests.Contains(ci) {
 221                                                 // We can't request this right now.
 222                                                 return
 223                                         }
 224                                 }
 225                                 requestHeap.requestIndexes = append(
 226                                         requestHeap.requestIndexes,
 227                                         p.t.pieceRequestIndexOffset(pieceIndex)+ci)
 228                         })
 229                 },
 230         )
 231         heap.Init(&requestHeap)
 232         for requestHeap.Len() != 0 && desired.Requests.GetCardinality() < uint64(p.nominalMaxRequests()) {
 233                 requestIndex := heap.Pop(&requestHeap).(RequestIndex)
 234                 desired.Requests.Add(requestIndex)
 235         }
 236         return
 237 }
 238
 239 func (p *Peer) applyNextRequestState() bool {
 240         if p.needRequestUpdate == "" {
 241                 return true
 242         }
 243         var more bool
 244         pprof.Do(
 245                 context.Background(),
 246                 pprof.Labels("update request", p.needRequestUpdate),
 247                 func(_ context.Context) {
 248                         next := p.getDesiredRequestState()
 249                         more = p.applyRequestState(next)
 250                 },
 251         )
 252         return more
 253 }
 254
 255 func (p *Peer) applyRequestState(next requestState) bool {
 256         current := p.actualRequestState
 257         if !p.setInterested(next.Interested) {
 258                 return false
 259         }
 260         more := true
 261         cancel := roaring.AndNot(&current.Requests, &next.Requests)
 262         cancel.Iterate(func(req uint32) bool {
 263                 more = p.cancel(req)
 264                 return more
 265         })
 266         if !more {
 267                 return false
 268         }
 269         next.Requests.Iterate(func(req uint32) bool {
 270                 if p.cancelledRequests.Contains(req) {
 271                         log.Printf("waiting for cancelled request %v", req)
 272                         return false
 273                 }
 274                 if maxRequests(current.Requests.GetCardinality()) >= p.nominalMaxRequests() {
 275                         log.Printf("not assigning all requests [desired=%v, cancelled=%v, max=%v]",
 276                                 next.Requests.GetCardinality(),
 277                                 p.cancelledRequests.GetCardinality(),
 278                                 p.nominalMaxRequests(),
 279                         )
 280                         return false
 281                 }
 282                 var err error
 283                 more, err = p.request(req)
 284                 if err != nil {
 285                         panic(err)
 286                 }
 287                 return more
 288         })
 289         if more {
 290                 p.needRequestUpdate = ""
 291         }
 292         return more
 293 }