webseed-peer.go

   1 package torrent
   2
   3 import (
   4         "context"
   5         "errors"
   6         "fmt"
   7         "math/rand"
   8         "sync"
   9         "time"
  10
  11         "github.com/RoaringBitmap/roaring"
  12         "github.com/anacrolix/log"
  13
  14         "github.com/anacrolix/torrent/metainfo"
  15         pp "github.com/anacrolix/torrent/peer_protocol"
  16         "github.com/anacrolix/torrent/webseed"
  17 )
  18
  19 type webseedPeer struct {
  20         // First field for stats alignment.
  21         peer           Peer
  22         client         webseed.Client
  23         activeRequests map[Request]webseed.Request
  24         requesterCond  sync.Cond
  25         // Number of requester routines.
  26         maxRequests int
  27 }
  28
  29 var _ peerImpl = (*webseedPeer)(nil)
  30
  31 func (me *webseedPeer) connStatusString() string {
  32         return me.client.Url
  33 }
  34
  35 func (ws *webseedPeer) String() string {
  36         return fmt.Sprintf("webseed peer for %q", ws.client.Url)
  37 }
  38
  39 func (ws *webseedPeer) onGotInfo(info *metainfo.Info) {
  40         ws.client.SetInfo(info)
  41         // There should be probably be a callback in Client instead, so it can remove pieces at its whim
  42         // too.
  43         ws.client.Pieces.Iterate(func(x uint32) bool {
  44                 ws.peer.t.incPieceAvailability(pieceIndex(x))
  45                 return true
  46         })
  47 }
  48
  49 func (ws *webseedPeer) writeInterested(interested bool) bool {
  50         return true
  51 }
  52
  53 func (ws *webseedPeer) _cancel(r RequestIndex) bool {
  54         if active, ok := ws.activeRequests[ws.peer.t.requestIndexToRequest(r)]; ok {
  55                 active.Cancel()
  56                 // The requester is running and will handle the result.
  57                 return true
  58         }
  59         // There should be no requester handling this, so no further events will occur.
  60         return false
  61 }
  62
  63 func (ws *webseedPeer) intoSpec(r Request) webseed.RequestSpec {
  64         return webseed.RequestSpec{ws.peer.t.requestOffset(r), int64(r.Length)}
  65 }
  66
  67 func (ws *webseedPeer) _request(r Request) bool {
  68         ws.requesterCond.Signal()
  69         return true
  70 }
  71
  72 func (ws *webseedPeer) doRequest(r Request) error {
  73         webseedRequest := ws.client.NewRequest(ws.intoSpec(r))
  74         ws.activeRequests[r] = webseedRequest
  75         err := func() error {
  76                 ws.requesterCond.L.Unlock()
  77                 defer ws.requesterCond.L.Lock()
  78                 return ws.requestResultHandler(r, webseedRequest)
  79         }()
  80         delete(ws.activeRequests, r)
  81         return err
  82 }
  83
  84 func (ws *webseedPeer) requester(i int) {
  85         ws.requesterCond.L.Lock()
  86         defer ws.requesterCond.L.Unlock()
  87 start:
  88         for !ws.peer.closed.IsSet() {
  89                 restart := false
  90                 ws.peer.requestState.Requests.Iterate(func(x RequestIndex) bool {
  91                         r := ws.peer.t.requestIndexToRequest(x)
  92                         if _, ok := ws.activeRequests[r]; ok {
  93                                 return true
  94                         }
  95                         err := ws.doRequest(r)
  96                         ws.requesterCond.L.Unlock()
  97                         if err != nil && !errors.Is(err, context.Canceled) {
  98                                 log.Printf("requester %v: error doing webseed request %v: %v", i, r, err)
  99                         }
 100                         restart = true
 101                         if errors.Is(err, webseed.ErrTooFast) {
 102                                 time.Sleep(time.Duration(rand.Int63n(int64(10 * time.Second))))
 103                         }
 104                         ws.requesterCond.L.Lock()
 105                         return false
 106                 })
 107                 if restart {
 108                         goto start
 109                 }
 110                 ws.requesterCond.Wait()
 111         }
 112 }
 113
 114 func (ws *webseedPeer) connectionFlags() string {
 115         return "WS"
 116 }
 117
 118 // Maybe this should drop all existing connections, or something like that.
 119 func (ws *webseedPeer) drop() {}
 120
 121 func (cn *webseedPeer) ban() {
 122         cn.peer.close()
 123 }
 124
 125 func (ws *webseedPeer) handleUpdateRequests() {
 126         // Because this is synchronous, webseed peers seem to get first dibs on newly prioritized
 127         // pieces.
 128         go func() {
 129                 ws.peer.t.cl.lock()
 130                 defer ws.peer.t.cl.unlock()
 131                 ws.peer.maybeUpdateActualRequestState()
 132         }()
 133 }
 134
 135 func (ws *webseedPeer) onClose() {
 136         ws.peer.logger.Levelf(log.Debug, "closing")
 137         // Just deleting them means we would have to manually cancel active requests.
 138         ws.peer.cancelAllRequests()
 139         ws.peer.t.iterPeers(func(p *Peer) {
 140                 if p.isLowOnRequests() {
 141                         p.updateRequests("webseedPeer.onClose")
 142                 }
 143         })
 144         ws.requesterCond.Broadcast()
 145 }
 146
 147 func (ws *webseedPeer) requestResultHandler(r Request, webseedRequest webseed.Request) error {
 148         result := <-webseedRequest.Result
 149         close(webseedRequest.Result) // one-shot
 150         // We do this here rather than inside receiveChunk, since we want to count errors too. I'm not
 151         // sure if we can divine which errors indicate cancellation on our end without hitting the
 152         // network though.
 153         if len(result.Bytes) != 0 || result.Err == nil {
 154                 // Increment ChunksRead and friends
 155                 ws.peer.doChunkReadStats(int64(len(result.Bytes)))
 156         }
 157         ws.peer.readBytes(int64(len(result.Bytes)))
 158         ws.peer.t.cl.lock()
 159         defer ws.peer.t.cl.unlock()
 160         if ws.peer.t.closed.IsSet() {
 161                 return nil
 162         }
 163         err := result.Err
 164         if err != nil {
 165                 switch {
 166                 case errors.Is(err, context.Canceled):
 167                 case errors.Is(err, webseed.ErrTooFast):
 168                 case ws.peer.closed.IsSet():
 169                 default:
 170                         ws.peer.logger.Printf("Request %v rejected: %v", r, result.Err)
 171                         // // Here lies my attempt to extract something concrete from Go's error system. RIP.
 172                         // cfg := spew.NewDefaultConfig()
 173                         // cfg.DisableMethods = true
 174                         // cfg.Dump(result.Err)
 175                         log.Printf("closing %v", ws)
 176                         ws.peer.close()
 177                 }
 178                 if !ws.peer.remoteRejectedRequest(ws.peer.t.requestIndexFromRequest(r)) {
 179                         panic("invalid reject")
 180                 }
 181                 return err
 182         }
 183         err = ws.peer.receiveChunk(&pp.Message{
 184                 Type:  pp.Piece,
 185                 Index: r.Index,
 186                 Begin: r.Begin,
 187                 Piece: result.Bytes,
 188         })
 189         if err != nil {
 190                 panic(err)
 191         }
 192         return err
 193 }
 194
 195 func (me *webseedPeer) peerPieces() *roaring.Bitmap {
 196         return &me.client.Pieces
 197 }
 198
 199 func (cn *webseedPeer) peerHasAllPieces() (all, known bool) {
 200         if !cn.peer.t.haveInfo() {
 201                 return true, false
 202         }
 203         return cn.client.Pieces.GetCardinality() == uint64(cn.peer.t.numPieces()), true
 204 }