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/missinggo/v2/bitmap"
  15         "github.com/anacrolix/multiless"
  16
  17         request_strategy "github.com/anacrolix/torrent/request-strategy"
  18 )
  19
  20 func (cl *Client) tickleRequester() {
  21         cl.updateRequests.Broadcast()
  22 }
  23
  24 func (cl *Client) getRequestStrategyInput() request_strategy.Input {
  25         ts := make([]request_strategy.Torrent, 0, len(cl.torrents))
  26         for _, t := range cl.torrents {
  27                 if !t.haveInfo() {
  28                         // This would be removed if metadata is handled here. We have to guard against not
  29                         // knowing the piece size. If we have no info, we have no pieces too, so the end result
  30                         // is the same.
  31                         continue
  32                 }
  33                 rst := request_strategy.Torrent{
  34                         InfoHash:       t.infoHash,
  35                         ChunksPerPiece: t.chunksPerRegularPiece(),
  36                 }
  37                 if t.storage != nil {
  38                         rst.Capacity = t.storage.Capacity
  39                 }
  40                 rst.Pieces = make([]request_strategy.Piece, 0, len(t.pieces))
  41                 for i := range t.pieces {
  42                         p := &t.pieces[i]
  43                         rst.Pieces = append(rst.Pieces, request_strategy.Piece{
  44                                 Request:           !t.ignorePieceForRequests(i),
  45                                 Priority:          p.purePriority(),
  46                                 Partial:           t.piecePartiallyDownloaded(i),
  47                                 Availability:      p.availability,
  48                                 Length:            int64(p.length()),
  49                                 NumPendingChunks:  int(t.pieceNumPendingChunks(i)),
  50                                 IterPendingChunks: p.undirtiedChunksIter(),
  51                         })
  52                 }
  53                 t.iterPeers(func(p *Peer) {
  54                         if p.closed.IsSet() {
  55                                 return
  56                         }
  57                         if p.piecesReceivedSinceLastRequestUpdate > p.maxPiecesReceivedBetweenRequestUpdates {
  58                                 p.maxPiecesReceivedBetweenRequestUpdates = p.piecesReceivedSinceLastRequestUpdate
  59                         }
  60                         p.piecesReceivedSinceLastRequestUpdate = 0
  61                         rst.Peers = append(rst.Peers, request_strategy.Peer{
  62                                 Pieces:           *p.newPeerPieces(),
  63                                 MaxRequests:      p.nominalMaxRequests(),
  64                                 ExistingRequests: p.actualRequestState.Requests,
  65                                 Choking:          p.peerChoking,
  66                                 PieceAllowedFast: p.peerAllowedFast,
  67                                 DownloadRate:     p.downloadRate(),
  68                                 Age:              time.Since(p.completedHandshake),
  69                                 Id: peerId{
  70                                         Peer: p,
  71                                         ptr:  uintptr(unsafe.Pointer(p)),
  72                                 },
  73                         })
  74                 })
  75                 ts = append(ts, rst)
  76         }
  77         return request_strategy.Input{
  78                 Torrents:           ts,
  79                 MaxUnverifiedBytes: cl.config.MaxUnverifiedBytes,
  80         }
  81 }
  82
  83 func init() {
  84         gob.Register(peerId{})
  85 }
  86
  87 type peerId struct {
  88         *Peer
  89         ptr uintptr
  90 }
  91
  92 func (p peerId) Uintptr() uintptr {
  93         return p.ptr
  94 }
  95
  96 func (p peerId) GobEncode() (b []byte, _ error) {
  97         *(*reflect.SliceHeader)(unsafe.Pointer(&b)) = reflect.SliceHeader{
  98                 Data: uintptr(unsafe.Pointer(&p.ptr)),
  99                 Len:  int(unsafe.Sizeof(p.ptr)),
 100                 Cap:  int(unsafe.Sizeof(p.ptr)),
 101         }
 102         return
 103 }
 104
 105 func (p *peerId) GobDecode(b []byte) error {
 106         if uintptr(len(b)) != unsafe.Sizeof(p.ptr) {
 107                 panic(len(b))
 108         }
 109         ptr := unsafe.Pointer(&b[0])
 110         p.ptr = *(*uintptr)(ptr)
 111         log.Printf("%p", ptr)
 112         dst := reflect.SliceHeader{
 113                 Data: uintptr(unsafe.Pointer(&p.Peer)),
 114                 Len:  int(unsafe.Sizeof(p.Peer)),
 115                 Cap:  int(unsafe.Sizeof(p.Peer)),
 116         }
 117         copy(*(*[]byte)(unsafe.Pointer(&dst)), b)
 118         return nil
 119 }
 120
 121 type RequestIndex = request_strategy.RequestIndex
 122 type chunkIndexType = request_strategy.ChunkIndex
 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                 // I have a hunch that this could trigger for requests for chunks that are choked and not
 148                 // allowed fast, since the current conn shouldn't already be included. It's a very specific
 149                 // circumstance, and if it triggers I will fix it.
 150                 if ret < 0 {
 151                         panic(ret)
 152                 }
 153                 return ret
 154         }
 155         ml := multiless.New()
 156         // Push requests that can't be served right now to the end. But we don't throw them away unless
 157         // there's a better alternative. This is for when we're using the fast extension and get choked
 158         // but our requests could still be good when we get unchoked.
 159         if p.peer.peerChoking {
 160                 ml = ml.Bool(
 161                         !p.peer.peerAllowedFast.Contains(leftPieceIndex),
 162                         !p.peer.peerAllowedFast.Contains(rightPieceIndex),
 163                 )
 164         }
 165         ml = ml.Int(
 166                 pending(leftRequest, leftCurrent),
 167                 pending(rightRequest, rightCurrent))
 168         ml = ml.Bool(!leftCurrent, !rightCurrent)
 169         ml = ml.Int(
 170                 -int(p.torrentStrategyInput.Pieces[leftPieceIndex].Priority),
 171                 -int(p.torrentStrategyInput.Pieces[rightPieceIndex].Priority),
 172         )
 173         ml = ml.Int(
 174                 int(p.torrentStrategyInput.Pieces[leftPieceIndex].Availability),
 175                 int(p.torrentStrategyInput.Pieces[rightPieceIndex].Availability))
 176         ml = ml.Uint32(leftPieceIndex, rightPieceIndex)
 177         ml = ml.Uint32(leftRequest, rightRequest)
 178         return ml.MustLess()
 179 }
 180
 181 func (p *peerRequests) Swap(i, j int) {
 182         p.requestIndexes[i], p.requestIndexes[j] = p.requestIndexes[j], p.requestIndexes[i]
 183 }
 184
 185 func (p *peerRequests) Push(x interface{}) {
 186         p.requestIndexes = append(p.requestIndexes, x.(RequestIndex))
 187 }
 188
 189 func (p *peerRequests) Pop() interface{} {
 190         last := len(p.requestIndexes) - 1
 191         x := p.requestIndexes[last]
 192         p.requestIndexes = p.requestIndexes[:last]
 193         return x
 194 }
 195
 196 func (p *Peer) getDesiredRequestState() (desired requestState) {
 197         input := p.t.cl.getRequestStrategyInput()
 198         requestHeap := peerRequests{
 199                 peer: p,
 200         }
 201         for _, t := range input.Torrents {
 202                 if t.InfoHash == p.t.infoHash {
 203                         requestHeap.torrentStrategyInput = t
 204                         break
 205                 }
 206         }
 207         request_strategy.GetRequestablePieces(
 208                 input,
 209                 func(t *request_strategy.Torrent, rsp *request_strategy.Piece, pieceIndex int) {
 210                         if t.InfoHash != p.t.infoHash {
 211                                 return
 212                         }
 213                         if !p.peerHasPiece(pieceIndex) {
 214                                 return
 215                         }
 216                         allowedFast := p.peerAllowedFast.ContainsInt(pieceIndex)
 217                         rsp.IterPendingChunks.Iter(func(ci request_strategy.ChunkIndex) {
 218                                 if !allowedFast {
 219                                         // We must signal interest to request this..
 220                                         desired.Interested = true
 221                                         if p.peerChoking && !p.actualRequestState.Requests.Contains(ci) {
 222                                                 // We can't request this right now.
 223                                                 return
 224                                         }
 225                                 }
 226                                 requestHeap.requestIndexes = append(
 227                                         requestHeap.requestIndexes,
 228                                         p.t.pieceRequestIndexOffset(pieceIndex)+ci)
 229                         })
 230                 },
 231         )
 232         heap.Init(&requestHeap)
 233         for requestHeap.Len() != 0 && desired.Requests.GetCardinality() < uint64(p.nominalMaxRequests()) {
 234                 requestIndex := heap.Pop(&requestHeap).(RequestIndex)
 235                 desired.Requests.Add(requestIndex)
 236         }
 237         return
 238 }
 239
 240 func (p *Peer) applyNextRequestState() bool {
 241         if p.needRequestUpdate == "" {
 242                 return true
 243         }
 244         var more bool
 245         pprof.Do(
 246                 context.Background(),
 247                 pprof.Labels("update request", p.needRequestUpdate),
 248                 func(_ context.Context) {
 249                         next := p.getDesiredRequestState()
 250                         more = p.applyRequestState(next)
 251                 },
 252         )
 253         return more
 254 }
 255
 256 func (p *Peer) applyRequestState(next requestState) bool {
 257         current := p.actualRequestState
 258         if !p.setInterested(next.Interested) {
 259                 return false
 260         }
 261         more := true
 262         cancel := roaring.AndNot(&current.Requests, &next.Requests)
 263         cancel.Iterate(func(req uint32) bool {
 264                 more = p.cancel(req)
 265                 return more
 266         })
 267         if !more {
 268                 return false
 269         }
 270         next.Requests.Iterate(func(req uint32) bool {
 271                 // This could happen if the peer chokes us between the next state being generated, and us
 272                 // trying to transmit the state.
 273                 if p.peerChoking && !p.peerAllowedFast.Contains(bitmap.BitIndex(req/p.t.chunksPerRegularPiece())) {
 274                         return true
 275                 }
 276                 var err error
 277                 more, err = p.request(req)
 278                 if err != nil {
 279                         panic(err)
 280                 } /* else {
 281                         log.Print(req)
 282                 } */
 283                 return more
 284         })
 285         if more {
 286                 p.needRequestUpdate = ""
 287         }
 288         return more
 289 }