forked from cerc-io/ipld-eth-server
63 lines
1.4 KiB
Go
63 lines
1.4 KiB
Go
package kbucket
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import (
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"bytes"
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"crypto/sha256"
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"errors"
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u "github.com/ipfs/go-ipfs-util"
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ks "github.com/libp2p/go-libp2p-kbucket/keyspace"
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peer "github.com/libp2p/go-libp2p-peer"
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)
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// Returned if a routing table query returns no results. This is NOT expected
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// behaviour
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var ErrLookupFailure = errors.New("failed to find any peer in table")
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// ID for IpfsDHT is in the XORKeySpace
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//
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// The type dht.ID signifies that its contents have been hashed from either a
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// peer.ID or a util.Key. This unifies the keyspace
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type ID []byte
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func (id ID) equal(other ID) bool {
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return bytes.Equal(id, other)
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}
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func (id ID) less(other ID) bool {
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a := ks.Key{Space: ks.XORKeySpace, Bytes: id}
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b := ks.Key{Space: ks.XORKeySpace, Bytes: other}
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return a.Less(b)
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}
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func xor(a, b ID) ID {
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return ID(u.XOR(a, b))
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}
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func CommonPrefixLen(a, b ID) int {
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return ks.ZeroPrefixLen(u.XOR(a, b))
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}
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// ConvertPeerID creates a DHT ID by hashing a Peer ID (Multihash)
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func ConvertPeerID(id peer.ID) ID {
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hash := sha256.Sum256([]byte(id))
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return hash[:]
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}
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// ConvertKey creates a DHT ID by hashing a local key (String)
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func ConvertKey(id string) ID {
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hash := sha256.Sum256([]byte(id))
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return hash[:]
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}
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// Closer returns true if a is closer to key than b is
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func Closer(a, b peer.ID, key string) bool {
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aid := ConvertPeerID(a)
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bid := ConvertPeerID(b)
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tgt := ConvertKey(key)
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adist := xor(aid, tgt)
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bdist := xor(bid, tgt)
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return adist.less(bdist)
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}
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