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20 lines
621 B
Go
20 lines
621 B
Go
package random
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import (
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"encoding/binary"
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"github.com/sot-tech/mochi/bittorrent"
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)
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// DeriveEntropyFromRequest generates 2*64 bits of pseudo random state from an
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// AnnounceRequest.
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//
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// Calling DeriveEntropyFromRequest multiple times yields the same values.
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func DeriveEntropyFromRequest(req *bittorrent.AnnounceRequest) (v0 uint64, v1 uint64) {
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if len(req.InfoHash) >= bittorrent.InfoHashV1Len {
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v0 = binary.BigEndian.Uint64([]byte(req.InfoHash[:8])) + binary.BigEndian.Uint64([]byte(req.InfoHash[8:16]))
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}
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v1 = binary.BigEndian.Uint64(req.Peer.ID[:8]) + binary.BigEndian.Uint64(req.Peer.ID[8:16])
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return
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}
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