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