requesting.go

   1 package torrent
   2
   3 import (
   4         "container/heap"
   5         "context"
   6         "encoding/gob"
   7         "math/rand"
   8         "reflect"
   9         "runtime/pprof"
  10         "time"
  11         "unsafe"
  12
  13         "github.com/anacrolix/log"
  14         "github.com/anacrolix/multiless"
  15
  16         request_strategy "github.com/anacrolix/torrent/request-strategy"
  17 )
  18
  19 // Returns what is necessary to run request_strategy.GetRequestablePieces for primaryTorrent.
  20 func (cl *Client) getRequestStrategyInput(primaryTorrent *Torrent) (input request_strategy.Input) {
  21         input.MaxUnverifiedBytes = cl.config.MaxUnverifiedBytes
  22         if !primaryTorrent.haveInfo() {
  23                 return
  24         }
  25         if capFunc := primaryTorrent.storage.Capacity; capFunc != nil {
  26                 if cap, ok := (*capFunc)(); ok {
  27                         input.Capacity = &cap
  28                 }
  29         }
  30         if false {
  31                 if input.Capacity == nil {
  32                         input.Torrents = []request_strategy.Torrent{primaryTorrent.requestStrategyTorrentInput()}
  33                         return
  34                 }
  35         }
  36         input.Torrents = make([]request_strategy.Torrent, 0, len(cl.torrents))
  37         for _, t := range cl.torrents {
  38                 if !t.haveInfo() {
  39                         // This would be removed if metadata is handled here. Determining chunks per piece
  40                         // requires the info. If we have no info, we have no pieces too, so the end result is
  41                         // the same.
  42                         continue
  43                 }
  44                 if t.storage.Capacity != primaryTorrent.storage.Capacity {
  45                         continue
  46                 }
  47                 input.Torrents = append(input.Torrents, t.requestStrategyTorrentInput())
  48         }
  49         return
  50 }
  51
  52 func (t *Torrent) getRequestStrategyInput() request_strategy.Input {
  53         return t.cl.getRequestStrategyInput(t)
  54 }
  55
  56 func (t *Torrent) requestStrategyTorrentInput() request_strategy.Torrent {
  57         rst := request_strategy.Torrent{
  58                 InfoHash:       t.infoHash,
  59                 ChunksPerPiece: t.chunksPerRegularPiece(),
  60         }
  61         rst.Pieces = make([]request_strategy.Piece, 0, len(t.pieces))
  62         for i := range t.pieces {
  63                 rst.Pieces = append(rst.Pieces, t.makeRequestStrategyPiece(i))
  64         }
  65         return rst
  66 }
  67
  68 func (t *Torrent) requestStrategyPieceOrderState(i int) request_strategy.PieceRequestOrderState {
  69         return request_strategy.PieceRequestOrderState{
  70                 Priority:     t.piece(i).purePriority(),
  71                 Partial:      t.piecePartiallyDownloaded(i),
  72                 Availability: t.piece(i).availability,
  73         }
  74 }
  75
  76 func (t *Torrent) makeRequestStrategyPiece(i int) request_strategy.Piece {
  77         p := &t.pieces[i]
  78         return request_strategy.Piece{
  79                 Request:           !t.ignorePieceForRequests(i),
  80                 Priority:          p.purePriority(),
  81                 Partial:           t.piecePartiallyDownloaded(i),
  82                 Availability:      p.availability,
  83                 Length:            int64(p.length()),
  84                 NumPendingChunks:  int(t.pieceNumPendingChunks(i)),
  85                 IterPendingChunks: &p.undirtiedChunksIter,
  86         }
  87 }
  88
  89 func init() {
  90         gob.Register(peerId{})
  91 }
  92
  93 type peerId struct {
  94         *Peer
  95         ptr uintptr
  96 }
  97
  98 func (p peerId) Uintptr() uintptr {
  99         return p.ptr
 100 }
 101
 102 func (p peerId) GobEncode() (b []byte, _ error) {
 103         *(*reflect.SliceHeader)(unsafe.Pointer(&b)) = reflect.SliceHeader{
 104                 Data: uintptr(unsafe.Pointer(&p.ptr)),
 105                 Len:  int(unsafe.Sizeof(p.ptr)),
 106                 Cap:  int(unsafe.Sizeof(p.ptr)),
 107         }
 108         return
 109 }
 110
 111 func (p *peerId) GobDecode(b []byte) error {
 112         if uintptr(len(b)) != unsafe.Sizeof(p.ptr) {
 113                 panic(len(b))
 114         }
 115         ptr := unsafe.Pointer(&b[0])
 116         p.ptr = *(*uintptr)(ptr)
 117         log.Printf("%p", ptr)
 118         dst := reflect.SliceHeader{
 119                 Data: uintptr(unsafe.Pointer(&p.Peer)),
 120                 Len:  int(unsafe.Sizeof(p.Peer)),
 121                 Cap:  int(unsafe.Sizeof(p.Peer)),
 122         }
 123         copy(*(*[]byte)(unsafe.Pointer(&dst)), b)
 124         return nil
 125 }
 126
 127 type (
 128         RequestIndex   = request_strategy.RequestIndex
 129         chunkIndexType = request_strategy.ChunkIndex
 130 )
 131
 132 type peerRequests struct {
 133         requestIndexes       []RequestIndex
 134         peer                 *Peer
 135         torrentStrategyInput *request_strategy.Torrent
 136 }
 137
 138 func (p *peerRequests) Len() int {
 139         return len(p.requestIndexes)
 140 }
 141
 142 func (p *peerRequests) Less(i, j int) bool {
 143         leftRequest := p.requestIndexes[i]
 144         rightRequest := p.requestIndexes[j]
 145         t := p.peer.t
 146         leftPieceIndex := leftRequest / p.torrentStrategyInput.ChunksPerPiece
 147         rightPieceIndex := rightRequest / p.torrentStrategyInput.ChunksPerPiece
 148         leftCurrent := p.peer.actualRequestState.Requests.Contains(leftRequest)
 149         rightCurrent := p.peer.actualRequestState.Requests.Contains(rightRequest)
 150         pending := func(index RequestIndex, current bool) int {
 151                 ret := t.pendingRequests.Get(index)
 152                 if current {
 153                         ret--
 154                 }
 155                 // See https://github.com/anacrolix/torrent/issues/679 for possible issues. This should be
 156                 // resolved.
 157                 if ret < 0 {
 158                         panic(ret)
 159                 }
 160                 return ret
 161         }
 162         ml := multiless.New()
 163         // Push requests that can't be served right now to the end. But we don't throw them away unless
 164         // there's a better alternative. This is for when we're using the fast extension and get choked
 165         // but our requests could still be good when we get unchoked.
 166         if p.peer.peerChoking {
 167                 ml = ml.Bool(
 168                         !p.peer.peerAllowedFast.Contains(leftPieceIndex),
 169                         !p.peer.peerAllowedFast.Contains(rightPieceIndex),
 170                 )
 171         }
 172         ml = ml.Int(
 173                 pending(leftRequest, leftCurrent),
 174                 pending(rightRequest, rightCurrent))
 175         ml = ml.Bool(!leftCurrent, !rightCurrent)
 176         ml = ml.Int(
 177                 -int(p.torrentStrategyInput.Pieces[leftPieceIndex].Priority),
 178                 -int(p.torrentStrategyInput.Pieces[rightPieceIndex].Priority),
 179         )
 180         ml = ml.Int(
 181                 int(p.torrentStrategyInput.Pieces[leftPieceIndex].Availability),
 182                 int(p.torrentStrategyInput.Pieces[rightPieceIndex].Availability))
 183         ml = ml.Uint32(leftPieceIndex, rightPieceIndex)
 184         ml = ml.Uint32(leftRequest, rightRequest)
 185         return ml.MustLess()
 186 }
 187
 188 func (p *peerRequests) Swap(i, j int) {
 189         p.requestIndexes[i], p.requestIndexes[j] = p.requestIndexes[j], p.requestIndexes[i]
 190 }
 191
 192 func (p *peerRequests) Push(x interface{}) {
 193         p.requestIndexes = append(p.requestIndexes, x.(RequestIndex))
 194 }
 195
 196 func (p *peerRequests) Pop() interface{} {
 197         last := len(p.requestIndexes) - 1
 198         x := p.requestIndexes[last]
 199         p.requestIndexes = p.requestIndexes[:last]
 200         return x
 201 }
 202
 203 type desiredRequestState struct {
 204         Requests   []RequestIndex
 205         Interested bool
 206 }
 207
 208 func (p *Peer) getDesiredRequestState() (desired desiredRequestState) {
 209         input := p.t.getRequestStrategyInput()
 210         requestHeap := peerRequests{
 211                 peer: p,
 212         }
 213         for i := range input.Torrents {
 214                 t := &input.Torrents[i]
 215                 if t.InfoHash == p.t.infoHash {
 216                         requestHeap.torrentStrategyInput = t
 217                         break
 218                 }
 219         }
 220         request_strategy.GetRequestablePieces(
 221                 input,
 222                 p.t.cl.pieceRequestOrder[p.t.storage.Capacity],
 223                 func(t *request_strategy.Torrent, rsp *request_strategy.Piece, pieceIndex int) {
 224                         if t.InfoHash != p.t.infoHash {
 225                                 return
 226                         }
 227                         if !p.peerHasPiece(pieceIndex) {
 228                                 return
 229                         }
 230                         allowedFast := p.peerAllowedFast.ContainsInt(pieceIndex)
 231                         rsp.IterPendingChunks.Iter(func(ci request_strategy.ChunkIndex) {
 232                                 r := p.t.pieceRequestIndexOffset(pieceIndex) + ci
 233                                 // if p.t.pendingRequests.Get(r) != 0 && !p.actualRequestState.Requests.Contains(r) {
 234                                 //      return
 235                                 // }
 236                                 if !allowedFast {
 237                                         // We must signal interest to request this
 238                                         desired.Interested = true
 239                                         // We can make or will allow sustaining a request here if we're not choked, or
 240                                         // have made the request previously (presumably while unchoked), and haven't had
 241                                         // the peer respond yet (and the request was retained because we are using the
 242                                         // fast extension).
 243                                         if p.peerChoking && !p.actualRequestState.Requests.Contains(r) {
 244                                                 // We can't request this right now.
 245                                                 return
 246                                         }
 247                                 }
 248                                 requestHeap.requestIndexes = append(requestHeap.requestIndexes, r)
 249                         })
 250                 },
 251         )
 252         p.t.assertPendingRequests()
 253         heap.Init(&requestHeap)
 254         for requestHeap.Len() != 0 && len(desired.Requests) < p.nominalMaxRequests() {
 255                 requestIndex := heap.Pop(&requestHeap).(RequestIndex)
 256                 desired.Requests = append(desired.Requests, requestIndex)
 257         }
 258         return
 259 }
 260
 261 func (p *Peer) maybeUpdateActualRequestState() bool {
 262         if p.needRequestUpdate == "" {
 263                 return true
 264         }
 265         var more bool
 266         pprof.Do(
 267                 context.Background(),
 268                 pprof.Labels("update request", p.needRequestUpdate),
 269                 func(_ context.Context) {
 270                         next := p.getDesiredRequestState()
 271                         more = p.applyRequestState(next)
 272                 },
 273         )
 274         return more
 275 }
 276
 277 // Transmit/action the request state to the peer.
 278 func (p *Peer) applyRequestState(next desiredRequestState) bool {
 279         current := &p.actualRequestState
 280         if !p.setInterested(next.Interested) {
 281                 return false
 282         }
 283         more := true
 284         cancel := current.Requests.Clone()
 285         for _, ri := range next.Requests {
 286                 cancel.Remove(ri)
 287         }
 288         cancel.Iterate(func(req uint32) bool {
 289                 more = p.cancel(req)
 290                 return more
 291         })
 292         if !more {
 293                 return false
 294         }
 295         shuffled := false
 296         lastPending := 0
 297         for i := 0; i < len(next.Requests); i++ {
 298                 req := next.Requests[i]
 299                 if p.cancelledRequests.Contains(req) {
 300                         // Waiting for a reject or piece message, which will suitably trigger us to update our
 301                         // requests, so we can skip this one with no additional consideration.
 302                         continue
 303                 }
 304                 // The cardinality of our desired requests shouldn't exceed the max requests since it's used
 305                 // in the calculation of the requests. However, if we cancelled requests and they haven't
 306                 // been rejected or serviced yet with the fast extension enabled, we can end up with more
 307                 // extra outstanding requests. We could subtract the number of outstanding cancels from the
 308                 // next request cardinality, but peers might not like that.
 309                 if maxRequests(current.Requests.GetCardinality()) >= p.nominalMaxRequests() {
 310                         // log.Printf("not assigning all requests [desired=%v, cancelled=%v, current=%v, max=%v]",
 311                         //      next.Requests.GetCardinality(),
 312                         //      p.cancelledRequests.GetCardinality(),
 313                         //      current.Requests.GetCardinality(),
 314                         //      p.nominalMaxRequests(),
 315                         // )
 316                         break
 317                 }
 318                 otherPending := p.t.pendingRequests.Get(next.Requests[0])
 319                 if p.actualRequestState.Requests.Contains(next.Requests[0]) {
 320                         otherPending--
 321                 }
 322                 if otherPending < lastPending {
 323                         // Pending should only rise. It's supposed to be the strongest ordering criteria. If it
 324                         // doesn't, our shuffling condition could be wrong.
 325                         panic(lastPending)
 326                 }
 327                 // If the request has already been requested by another peer, shuffle this and the rest of
 328                 // the requests (since according to the increasing condition, the rest of the indices
 329                 // already have an outstanding request with another peer).
 330                 if !shuffled && otherPending > 0 {
 331                         shuffleReqs := next.Requests[i:]
 332                         rand.Shuffle(len(shuffleReqs), func(i, j int) {
 333                                 shuffleReqs[i], shuffleReqs[j] = shuffleReqs[j], shuffleReqs[i]
 334                         })
 335                         // log.Printf("shuffled reqs [%v:%v]", i, len(next.Requests))
 336                         shuffled = true
 337                         // Repeat this index
 338                         i--
 339                         continue
 340                 }
 341
 342                 more = p.mustRequest(req)
 343                 if !more {
 344                         break
 345                 }
 346         }
 347         p.updateRequestsTimer.Stop()
 348         if more {
 349                 p.needRequestUpdate = ""
 350                 if !current.Requests.IsEmpty() {
 351                         p.updateRequestsTimer.Reset(3 * time.Second)
 352                 }
 353         }
 354         return more
 355 }