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