81 lines
1.5 KiB
Go
81 lines
1.5 KiB
Go
package torrent
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import (
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"crypto"
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"errors"
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"fmt"
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"time"
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pp "github.com/anacrolix/torrent/peer_protocol"
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)
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const (
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pieceHash = crypto.SHA1
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maxRequests = 250 // Maximum pending requests we allow peers to send us.
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chunkSize = 0x4000 // 16KiB
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bep20 = "-GT0000-" // Peer ID client identifier prefix
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nominalDialTimeout = time.Second * 30
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minDialTimeout = 5 * time.Second
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)
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type (
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InfoHash [20]byte
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pieceSum [20]byte
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)
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func (ih *InfoHash) AsString() string {
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return string(ih[:])
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}
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func (ih *InfoHash) HexString() string {
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return fmt.Sprintf("%x", ih[:])
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}
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func lastChunkSpec(pieceLength pp.Integer) (cs chunkSpec) {
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cs.Begin = (pieceLength - 1) / chunkSize * chunkSize
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cs.Length = pieceLength - cs.Begin
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return
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}
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type chunkSpec struct {
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Begin, Length pp.Integer
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}
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type request struct {
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Index pp.Integer
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chunkSpec
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}
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func newRequest(index, begin, length pp.Integer) request {
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return request{index, chunkSpec{begin, length}}
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}
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var (
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// Requested data not yet available.
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errDataNotReady = errors.New("data not ready")
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)
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// The size in bytes of a metadata extension piece.
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func metadataPieceSize(totalSize int, piece int) int {
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ret := totalSize - piece*(1<<14)
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if ret > 1<<14 {
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ret = 1 << 14
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}
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return ret
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}
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type superer interface {
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Super() interface{}
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}
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// Returns ok if there's a parent, and it's not nil.
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func super(child interface{}) (parent interface{}, ok bool) {
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s, ok := child.(superer)
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if !ok {
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return
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}
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parent = s.Super()
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ok = parent != nil
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return
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}
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