ceremonyclient/go-libp2p/core/peer/peer.go
Cassie Heart ebb31fd792 v1.4.19
2024-06-08 11:32:45 +00:00

195 lines
5.3 KiB
Go

// Package peer implements an object used to represent peers in the libp2p network.
package peer
import (
"errors"
"fmt"
"strings"
"github.com/ipfs/go-cid"
ic "github.com/libp2p/go-libp2p/core/crypto"
b58 "github.com/mr-tron/base58/base58"
mc "github.com/multiformats/go-multicodec"
mh "github.com/multiformats/go-multihash"
)
var (
// ErrEmptyPeerID is an error for empty peer ID.
ErrEmptyPeerID = errors.New("empty peer ID")
// ErrNoPublicKey is an error for peer IDs that don't embed public keys
ErrNoPublicKey = errors.New("public key is not embedded in peer ID")
)
// AdvancedEnableInlining enables automatically inlining keys shorter than
// 42 bytes into the peer ID (using the "identity" multihash function).
//
// WARNING: This flag will likely be set to false in the future and eventually
// be removed in favor of using a hash function specified by the key itself.
// See: https://github.com/libp2p/specs/issues/138
//
// DO NOT change this flag unless you know what you're doing.
//
// This currently defaults to true for backwards compatibility but will likely
// be set to false by default when an upgrade path is determined.
var AdvancedEnableInlining = true
const maxInlineKeyLength = 42
// ID is a libp2p peer identity.
//
// Peer IDs are derived by hashing a peer's public key and encoding the
// hash output as a multihash. See IDFromPublicKey for details.
type ID string
// Loggable returns a pretty peer ID string in loggable JSON format.
func (id ID) Loggable() map[string]interface{} {
return map[string]interface{}{
"peerID": id.String(),
}
}
func (id ID) String() string {
return b58.Encode([]byte(id))
}
// ShortString prints out the peer ID.
//
// TODO(brian): ensure correctness at ID generation and
// enforce this by only exposing functions that generate
// IDs safely. Then any peer.ID type found in the
// codebase is known to be correct.
func (id ID) ShortString() string {
pid := id.String()
if len(pid) <= 10 {
return fmt.Sprintf("<peer.ID %s>", pid)
}
return fmt.Sprintf("<peer.ID %s*%s>", pid[:2], pid[len(pid)-6:])
}
// MatchesPrivateKey tests whether this ID was derived from the secret key sk.
func (id ID) MatchesPrivateKey(sk ic.PrivKey) bool {
return id.MatchesPublicKey(sk.GetPublic())
}
// MatchesPublicKey tests whether this ID was derived from the public key pk.
func (id ID) MatchesPublicKey(pk ic.PubKey) bool {
oid, err := IDFromPublicKey(pk)
if err != nil {
return false
}
return oid == id
}
// ExtractPublicKey attempts to extract the public key from an ID.
//
// This method returns ErrNoPublicKey if the peer ID looks valid, but it can't extract
// the public key.
func (id ID) ExtractPublicKey() (ic.PubKey, error) {
decoded, err := mh.Decode([]byte(id))
if err != nil {
return nil, err
}
if decoded.Code != mh.IDENTITY {
return nil, ErrNoPublicKey
}
pk, err := ic.UnmarshalPublicKey(decoded.Digest)
if err != nil {
return nil, err
}
return pk, nil
}
// Validate checks if ID is empty or not.
func (id ID) Validate() error {
if id == ID("") {
return ErrEmptyPeerID
}
return nil
}
// IDFromBytes casts a byte slice to the ID type, and validates
// the value to make sure it is a multihash.
func IDFromBytes(b []byte) (ID, error) {
if _, err := mh.Cast(b); err != nil {
return ID(""), err
}
return ID(b), nil
}
// Decode accepts an encoded peer ID and returns the decoded ID if the input is
// valid.
//
// The encoded peer ID can either be a CID of a key or a raw multihash (identity
// or sha256-256).
func Decode(s string) (ID, error) {
if strings.HasPrefix(s, "Qm") || strings.HasPrefix(s, "1") {
// base58 encoded sha256 or identity multihash
m, err := mh.FromB58String(s)
if err != nil {
return "", fmt.Errorf("failed to parse peer ID: %s", err)
}
return ID(m), nil
}
c, err := cid.Decode(s)
if err != nil {
return "", fmt.Errorf("failed to parse peer ID: %s", err)
}
return FromCid(c)
}
// FromCid converts a CID to a peer ID, if possible.
func FromCid(c cid.Cid) (ID, error) {
code := mc.Code(c.Type())
if code != mc.Libp2pKey {
return "", fmt.Errorf("can't convert CID of type %q to a peer ID", code)
}
return ID(c.Hash()), nil
}
// ToCid encodes a peer ID as a CID of the public key.
//
// If the peer ID is invalid (e.g., empty), this will return the empty CID.
func ToCid(id ID) cid.Cid {
m, err := mh.Cast([]byte(id))
if err != nil {
return cid.Cid{}
}
return cid.NewCidV1(cid.Libp2pKey, m)
}
// IDFromPublicKey returns the Peer ID corresponding to the public key pk.
func IDFromPublicKey(pk ic.PubKey) (ID, error) {
b, err := ic.MarshalPublicKey(pk)
if err != nil {
return "", err
}
var alg uint64 = mh.SHA2_256
if AdvancedEnableInlining && len(b) <= maxInlineKeyLength {
alg = mh.IDENTITY
}
hash, _ := mh.Sum(b, alg, -1)
return ID(hash), nil
}
// IDFromPrivateKey returns the Peer ID corresponding to the secret key sk.
func IDFromPrivateKey(sk ic.PrivKey) (ID, error) {
return IDFromPublicKey(sk.GetPublic())
}
// IDSlice for sorting peers.
type IDSlice []ID
func (es IDSlice) Len() int { return len(es) }
func (es IDSlice) Swap(i, j int) { es[i], es[j] = es[j], es[i] }
func (es IDSlice) Less(i, j int) bool { return string(es[i]) < string(es[j]) }
func (es IDSlice) String() string {
peersStrings := make([]string, len(es))
for i, id := range es {
peersStrings[i] = id.String()
}
return strings.Join(peersStrings, ", ")
}