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