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