global.go

   1 package torrent
   2
   3 import (
   4         "crypto"
   5         "expvar"
   6         "time"
   7 )
   8
   9 const (
  10         pieceHash        = crypto.SHA1
  11         maxRequests      = 250    // Maximum pending requests we allow peers to send us.
  12         defaultChunkSize = 0x4000 // 16KiB
  13
  14         // Updated occasionally to when there's been some changes to client
  15         // behaviour in case other clients are assuming anything of us. See also
  16         // `bep20`.
  17         extendedHandshakeClientVersion = "go.torrent dev 20150624"
  18         // Peer ID client identifier prefix. We'll update this occasionally to
  19         // reflect changes to client behaviour that other clients may depend on.
  20         // Also see `extendedHandshakeClientVersion`.
  21         bep20 = "-GT0001-"
  22
  23         nominalDialTimeout = time.Second * 30
  24         minDialTimeout     = 5 * time.Second
  25
  26         // Justification for set bits follows.
  27         //
  28         // Extension protocol ([5]|=0x10):
  29         // http://www.bittorrent.org/beps/bep_0010.html
  30         //
  31         // Fast Extension ([7]|=0x04):
  32         // http://bittorrent.org/beps/bep_0006.html.
  33         // Disabled until AllowedFast is implemented.
  34         //
  35         // DHT ([7]|=1):
  36         // http://www.bittorrent.org/beps/bep_0005.html
  37         defaultExtensionBytes = "\x00\x00\x00\x00\x00\x10\x00\x01"
  38
  39         socketsPerTorrent     = 80
  40         torrentPeersHighWater = 200
  41         torrentPeersLowWater  = 50
  42
  43         // Limit how long handshake can take. This is to reduce the lingering
  44         // impact of a few bad apples. 4s loses 1% of successful handshakes that
  45         // are obtained with 60s timeout, and 5% of unsuccessful handshakes.
  46         handshakesTimeout = 20 * time.Second
  47
  48         // These are our extended message IDs. Peers will use these values to
  49         // select which extension a message is intended for.
  50         metadataExtendedId = iota + 1 // 0 is reserved for deleting keys
  51         pexExtendedId
  52 )
  53
  54 // I could move a lot of these counters to their own file, but I suspect they
  55 // may be attached to a Client someday.
  56 var (
  57         unwantedChunksReceived   = expvar.NewInt("chunksReceivedUnwanted")
  58         unexpectedChunksReceived = expvar.NewInt("chunksReceivedUnexpected")
  59         chunksReceived           = expvar.NewInt("chunksReceived")
  60
  61         peersAddedBySource = expvar.NewMap("peersAddedBySource")
  62
  63         uploadChunksPosted = expvar.NewInt("uploadChunksPosted")
  64         unexpectedCancels  = expvar.NewInt("unexpectedCancels")
  65         postedCancels      = expvar.NewInt("postedCancels")
  66
  67         pieceHashedCorrect    = expvar.NewInt("pieceHashedCorrect")
  68         pieceHashedNotCorrect = expvar.NewInt("pieceHashedNotCorrect")
  69
  70         unsuccessfulDials = expvar.NewInt("dialSuccessful")
  71         successfulDials   = expvar.NewInt("dialUnsuccessful")
  72
  73         acceptUTP    = expvar.NewInt("acceptUTP")
  74         acceptTCP    = expvar.NewInt("acceptTCP")
  75         acceptReject = expvar.NewInt("acceptReject")
  76
  77         peerExtensions                    = expvar.NewMap("peerExtensions")
  78         completedHandshakeConnectionFlags = expvar.NewMap("completedHandshakeConnectionFlags")
  79         // Count of connections to peer with same client ID.
  80         connsToSelf = expvar.NewInt("connsToSelf")
  81         // Number of completed connections to a client we're already connected with.
  82         duplicateClientConns       = expvar.NewInt("duplicateClientConns")
  83         receivedMessageTypes       = expvar.NewMap("receivedMessageTypes")
  84         receivedKeepalives         = expvar.NewInt("receivedKeepalives")
  85         supportedExtensionMessages = expvar.NewMap("supportedExtensionMessages")
  86         postedMessageTypes         = expvar.NewMap("postedMessageTypes")
  87         postedKeepalives           = expvar.NewInt("postedKeepalives")
  88         // Requests received for pieces we don't have.
  89         requestsReceivedForMissingPieces = expvar.NewInt("requestsReceivedForMissingPieces")
  90
  91         // Track the effectiveness of Torrent.connPieceInclinationPool.
  92         pieceInclinationsReused = expvar.NewInt("pieceInclinationsReused")
  93         pieceInclinationsNew    = expvar.NewInt("pieceInclinationsNew")
  94         pieceInclinationsPut    = expvar.NewInt("pieceInclinationsPut")
  95 )