113 lines
3.1 KiB
Go
113 lines
3.1 KiB
Go
package p2p
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import (
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"bytes"
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"encoding/hex"
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"fmt"
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"io/ioutil"
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crypto "github.com/tendermint/tendermint/crypto"
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"github.com/tendermint/tendermint/crypto/ed25519"
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cmn "github.com/tendermint/tendermint/libs/common"
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)
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// ID is a hex-encoded crypto.Address
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type ID string
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// IDByteLength is the length of a crypto.Address. Currently only 20.
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// TODO: support other length addresses ?
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const IDByteLength = 20
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//------------------------------------------------------------------------------
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// Persistent peer ID
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// TODO: encrypt on disk
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// NodeKey is the persistent peer key.
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// It contains the nodes private key for authentication.
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type NodeKey struct {
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PrivKey crypto.PrivKey `json:"priv_key"` // our priv key
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}
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// ID returns the peer's canonical ID - the hash of its public key.
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func (nodeKey *NodeKey) ID() ID {
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return PubKeyToID(nodeKey.PubKey())
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}
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// PubKey returns the peer's PubKey
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func (nodeKey *NodeKey) PubKey() crypto.PubKey {
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return nodeKey.PrivKey.PubKey()
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}
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// PubKeyToID returns the ID corresponding to the given PubKey.
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// It's the hex-encoding of the pubKey.Address().
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func PubKeyToID(pubKey crypto.PubKey) ID {
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return ID(hex.EncodeToString(pubKey.Address()))
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}
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// LoadOrGenNodeKey attempts to load the NodeKey from the given filePath.
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// If the file does not exist, it generates and saves a new NodeKey.
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func LoadOrGenNodeKey(filePath string) (*NodeKey, error) {
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if cmn.FileExists(filePath) {
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nodeKey, err := LoadNodeKey(filePath)
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if err != nil {
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return nil, err
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}
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return nodeKey, nil
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}
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return genNodeKey(filePath)
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}
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func LoadNodeKey(filePath string) (*NodeKey, error) {
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jsonBytes, err := ioutil.ReadFile(filePath)
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if err != nil {
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return nil, err
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}
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nodeKey := new(NodeKey)
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err = cdc.UnmarshalJSON(jsonBytes, nodeKey)
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if err != nil {
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return nil, fmt.Errorf("Error reading NodeKey from %v: %v", filePath, err)
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}
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return nodeKey, nil
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}
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func genNodeKey(filePath string) (*NodeKey, error) {
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privKey := ed25519.GenPrivKey()
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nodeKey := &NodeKey{
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PrivKey: privKey,
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}
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jsonBytes, err := cdc.MarshalJSON(nodeKey)
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if err != nil {
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return nil, err
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}
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err = ioutil.WriteFile(filePath, jsonBytes, 0600)
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if err != nil {
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return nil, err
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}
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return nodeKey, nil
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}
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//------------------------------------------------------------------------------
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// MakePoWTarget returns the big-endian encoding of 2^(targetBits - difficulty) - 1.
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// It can be used as a Proof of Work target.
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// NOTE: targetBits must be a multiple of 8 and difficulty must be less than targetBits.
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func MakePoWTarget(difficulty, targetBits uint) []byte {
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if targetBits%8 != 0 {
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panic(fmt.Sprintf("targetBits (%d) not a multiple of 8", targetBits))
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}
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if difficulty >= targetBits {
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panic(fmt.Sprintf("difficulty (%d) >= targetBits (%d)", difficulty, targetBits))
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}
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targetBytes := targetBits / 8
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zeroPrefixLen := (int(difficulty) / 8)
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prefix := bytes.Repeat([]byte{0}, zeroPrefixLen)
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mod := (difficulty % 8)
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if mod > 0 {
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nonZeroPrefix := byte(1<<(8-mod) - 1)
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prefix = append(prefix, nonZeroPrefix)
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}
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tailLen := int(targetBytes) - len(prefix)
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return append(prefix, bytes.Repeat([]byte{0xFF}, tailLen)...)
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}
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