57f959af41
I added localItemKey for this purpose in #18963, but then forgot to actually use it. This changes the database layout yet again and requires bumping the version number.
448 lines
13 KiB
Go
448 lines
13 KiB
Go
// Copyright 2015 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package enode
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import (
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"bytes"
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"crypto/rand"
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"encoding/binary"
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"fmt"
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"net"
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"os"
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"sync"
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"time"
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"github.com/ethereum/go-ethereum/rlp"
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"github.com/syndtr/goleveldb/leveldb"
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"github.com/syndtr/goleveldb/leveldb/errors"
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"github.com/syndtr/goleveldb/leveldb/iterator"
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"github.com/syndtr/goleveldb/leveldb/opt"
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"github.com/syndtr/goleveldb/leveldb/storage"
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"github.com/syndtr/goleveldb/leveldb/util"
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)
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// Keys in the node database.
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const (
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dbVersionKey = "version" // Version of the database to flush if changes
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dbNodePrefix = "n:" // Identifier to prefix node entries with
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dbLocalPrefix = "local:"
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dbDiscoverRoot = "v4"
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// These fields are stored per ID and IP, the full key is "n:<ID>:v4:<IP>:findfail".
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// Use nodeItemKey to create those keys.
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dbNodeFindFails = "findfail"
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dbNodePing = "lastping"
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dbNodePong = "lastpong"
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dbNodeSeq = "seq"
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// Local information is keyed by ID only, the full key is "local:<ID>:seq".
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// Use localItemKey to create those keys.
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dbLocalSeq = "seq"
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)
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const (
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dbNodeExpiration = 24 * time.Hour // Time after which an unseen node should be dropped.
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dbCleanupCycle = time.Hour // Time period for running the expiration task.
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dbVersion = 9
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)
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var zeroIP = make(net.IP, 16)
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// DB is the node database, storing previously seen nodes and any collected metadata about
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// them for QoS purposes.
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type DB struct {
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lvl *leveldb.DB // Interface to the database itself
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runner sync.Once // Ensures we can start at most one expirer
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quit chan struct{} // Channel to signal the expiring thread to stop
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}
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// OpenDB opens a node database for storing and retrieving infos about known peers in the
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// network. If no path is given an in-memory, temporary database is constructed.
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func OpenDB(path string) (*DB, error) {
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if path == "" {
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return newMemoryDB()
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}
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return newPersistentDB(path)
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}
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// newMemoryNodeDB creates a new in-memory node database without a persistent backend.
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func newMemoryDB() (*DB, error) {
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db, err := leveldb.Open(storage.NewMemStorage(), nil)
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if err != nil {
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return nil, err
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}
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return &DB{lvl: db, quit: make(chan struct{})}, nil
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}
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// newPersistentNodeDB creates/opens a leveldb backed persistent node database,
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// also flushing its contents in case of a version mismatch.
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func newPersistentDB(path string) (*DB, error) {
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opts := &opt.Options{OpenFilesCacheCapacity: 5}
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db, err := leveldb.OpenFile(path, opts)
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if _, iscorrupted := err.(*errors.ErrCorrupted); iscorrupted {
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db, err = leveldb.RecoverFile(path, nil)
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}
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if err != nil {
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return nil, err
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}
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// The nodes contained in the cache correspond to a certain protocol version.
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// Flush all nodes if the version doesn't match.
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currentVer := make([]byte, binary.MaxVarintLen64)
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currentVer = currentVer[:binary.PutVarint(currentVer, int64(dbVersion))]
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blob, err := db.Get([]byte(dbVersionKey), nil)
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switch err {
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case leveldb.ErrNotFound:
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// Version not found (i.e. empty cache), insert it
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if err := db.Put([]byte(dbVersionKey), currentVer, nil); err != nil {
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db.Close()
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return nil, err
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}
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case nil:
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// Version present, flush if different
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if !bytes.Equal(blob, currentVer) {
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db.Close()
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if err = os.RemoveAll(path); err != nil {
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return nil, err
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}
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return newPersistentDB(path)
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}
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}
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return &DB{lvl: db, quit: make(chan struct{})}, nil
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}
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// nodeKey returns the database key for a node record.
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func nodeKey(id ID) []byte {
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key := append([]byte(dbNodePrefix), id[:]...)
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key = append(key, ':')
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key = append(key, dbDiscoverRoot...)
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return key
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}
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// splitNodeKey returns the node ID of a key created by nodeKey.
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func splitNodeKey(key []byte) (id ID, rest []byte) {
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if !bytes.HasPrefix(key, []byte(dbNodePrefix)) {
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return ID{}, nil
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}
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item := key[len(dbNodePrefix):]
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copy(id[:], item[:len(id)])
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return id, item[len(id)+1:]
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}
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// nodeItemKey returns the database key for a node metadata field.
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func nodeItemKey(id ID, ip net.IP, field string) []byte {
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ip16 := ip.To16()
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if ip16 == nil {
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panic(fmt.Errorf("invalid IP (length %d)", len(ip)))
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}
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return bytes.Join([][]byte{nodeKey(id), ip16, []byte(field)}, []byte{':'})
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}
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// splitNodeItemKey returns the components of a key created by nodeItemKey.
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func splitNodeItemKey(key []byte) (id ID, ip net.IP, field string) {
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id, key = splitNodeKey(key)
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// Skip discover root.
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if string(key) == dbDiscoverRoot {
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return id, nil, ""
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}
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key = key[len(dbDiscoverRoot)+1:]
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// Split out the IP.
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ip = net.IP(key[:16])
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if ip4 := ip.To4(); ip4 != nil {
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ip = ip4
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}
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key = key[16+1:]
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// Field is the remainder of key.
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field = string(key)
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return id, ip, field
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}
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// localItemKey returns the key of a local node item.
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func localItemKey(id ID, field string) []byte {
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key := append([]byte(dbLocalPrefix), id[:]...)
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key = append(key, ':')
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key = append(key, field...)
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return key
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}
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// fetchInt64 retrieves an integer associated with a particular key.
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func (db *DB) fetchInt64(key []byte) int64 {
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blob, err := db.lvl.Get(key, nil)
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if err != nil {
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return 0
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}
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val, read := binary.Varint(blob)
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if read <= 0 {
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return 0
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}
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return val
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}
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// storeInt64 stores an integer in the given key.
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func (db *DB) storeInt64(key []byte, n int64) error {
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blob := make([]byte, binary.MaxVarintLen64)
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blob = blob[:binary.PutVarint(blob, n)]
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return db.lvl.Put(key, blob, nil)
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}
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// fetchUint64 retrieves an integer associated with a particular key.
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func (db *DB) fetchUint64(key []byte) uint64 {
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blob, err := db.lvl.Get(key, nil)
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if err != nil {
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return 0
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}
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val, _ := binary.Uvarint(blob)
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return val
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}
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// storeUint64 stores an integer in the given key.
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func (db *DB) storeUint64(key []byte, n uint64) error {
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blob := make([]byte, binary.MaxVarintLen64)
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blob = blob[:binary.PutUvarint(blob, n)]
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return db.lvl.Put(key, blob, nil)
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}
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// Node retrieves a node with a given id from the database.
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func (db *DB) Node(id ID) *Node {
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blob, err := db.lvl.Get(nodeKey(id), nil)
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if err != nil {
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return nil
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}
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return mustDecodeNode(id[:], blob)
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}
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func mustDecodeNode(id, data []byte) *Node {
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node := new(Node)
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if err := rlp.DecodeBytes(data, &node.r); err != nil {
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panic(fmt.Errorf("p2p/enode: can't decode node %x in DB: %v", id, err))
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}
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// Restore node id cache.
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copy(node.id[:], id)
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return node
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}
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// UpdateNode inserts - potentially overwriting - a node into the peer database.
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func (db *DB) UpdateNode(node *Node) error {
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if node.Seq() < db.NodeSeq(node.ID()) {
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return nil
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}
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blob, err := rlp.EncodeToBytes(&node.r)
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if err != nil {
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return err
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}
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if err := db.lvl.Put(nodeKey(node.ID()), blob, nil); err != nil {
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return err
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}
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return db.storeUint64(nodeItemKey(node.ID(), zeroIP, dbNodeSeq), node.Seq())
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}
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// NodeSeq returns the stored record sequence number of the given node.
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func (db *DB) NodeSeq(id ID) uint64 {
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return db.fetchUint64(nodeItemKey(id, zeroIP, dbNodeSeq))
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}
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// Resolve returns the stored record of the node if it has a larger sequence
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// number than n.
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func (db *DB) Resolve(n *Node) *Node {
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if n.Seq() > db.NodeSeq(n.ID()) {
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return n
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}
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return db.Node(n.ID())
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}
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// DeleteNode deletes all information associated with a node.
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func (db *DB) DeleteNode(id ID) {
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deleteRange(db.lvl, nodeKey(id))
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}
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func deleteRange(db *leveldb.DB, prefix []byte) {
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it := db.NewIterator(util.BytesPrefix(prefix), nil)
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defer it.Release()
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for it.Next() {
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db.Delete(it.Key(), nil)
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}
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}
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// ensureExpirer is a small helper method ensuring that the data expiration
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// mechanism is running. If the expiration goroutine is already running, this
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// method simply returns.
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//
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// The goal is to start the data evacuation only after the network successfully
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// bootstrapped itself (to prevent dumping potentially useful seed nodes). Since
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// it would require significant overhead to exactly trace the first successful
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// convergence, it's simpler to "ensure" the correct state when an appropriate
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// condition occurs (i.e. a successful bonding), and discard further events.
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func (db *DB) ensureExpirer() {
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db.runner.Do(func() { go db.expirer() })
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}
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// expirer should be started in a go routine, and is responsible for looping ad
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// infinitum and dropping stale data from the database.
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func (db *DB) expirer() {
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tick := time.NewTicker(dbCleanupCycle)
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defer tick.Stop()
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for {
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select {
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case <-tick.C:
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db.expireNodes()
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case <-db.quit:
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return
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}
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}
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}
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// expireNodes iterates over the database and deletes all nodes that have not
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// been seen (i.e. received a pong from) for some time.
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func (db *DB) expireNodes() {
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it := db.lvl.NewIterator(util.BytesPrefix([]byte(dbNodePrefix)), nil)
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defer it.Release()
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if !it.Next() {
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return
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}
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var (
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threshold = time.Now().Add(-dbNodeExpiration).Unix()
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youngestPong int64
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atEnd = false
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)
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for !atEnd {
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id, ip, field := splitNodeItemKey(it.Key())
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if field == dbNodePong {
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time, _ := binary.Varint(it.Value())
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if time > youngestPong {
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youngestPong = time
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}
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if time < threshold {
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// Last pong from this IP older than threshold, remove fields belonging to it.
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deleteRange(db.lvl, nodeItemKey(id, ip, ""))
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}
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}
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atEnd = !it.Next()
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nextID, _ := splitNodeKey(it.Key())
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if atEnd || nextID != id {
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// We've moved beyond the last entry of the current ID.
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// Remove everything if there was no recent enough pong.
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if youngestPong > 0 && youngestPong < threshold {
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deleteRange(db.lvl, nodeKey(id))
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}
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youngestPong = 0
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}
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}
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}
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// LastPingReceived retrieves the time of the last ping packet received from
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// a remote node.
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func (db *DB) LastPingReceived(id ID, ip net.IP) time.Time {
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return time.Unix(db.fetchInt64(nodeItemKey(id, ip, dbNodePing)), 0)
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}
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// UpdateLastPingReceived updates the last time we tried contacting a remote node.
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func (db *DB) UpdateLastPingReceived(id ID, ip net.IP, instance time.Time) error {
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return db.storeInt64(nodeItemKey(id, ip, dbNodePing), instance.Unix())
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}
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// LastPongReceived retrieves the time of the last successful pong from remote node.
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func (db *DB) LastPongReceived(id ID, ip net.IP) time.Time {
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// Launch expirer
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db.ensureExpirer()
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return time.Unix(db.fetchInt64(nodeItemKey(id, ip, dbNodePong)), 0)
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}
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// UpdateLastPongReceived updates the last pong time of a node.
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func (db *DB) UpdateLastPongReceived(id ID, ip net.IP, instance time.Time) error {
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return db.storeInt64(nodeItemKey(id, ip, dbNodePong), instance.Unix())
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}
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// FindFails retrieves the number of findnode failures since bonding.
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func (db *DB) FindFails(id ID, ip net.IP) int {
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return int(db.fetchInt64(nodeItemKey(id, ip, dbNodeFindFails)))
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}
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// UpdateFindFails updates the number of findnode failures since bonding.
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func (db *DB) UpdateFindFails(id ID, ip net.IP, fails int) error {
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return db.storeInt64(nodeItemKey(id, ip, dbNodeFindFails), int64(fails))
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}
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// LocalSeq retrieves the local record sequence counter.
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func (db *DB) localSeq(id ID) uint64 {
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return db.fetchUint64(localItemKey(id, dbLocalSeq))
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}
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// storeLocalSeq stores the local record sequence counter.
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func (db *DB) storeLocalSeq(id ID, n uint64) {
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db.storeUint64(localItemKey(id, dbLocalSeq), n)
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}
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// QuerySeeds retrieves random nodes to be used as potential seed nodes
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// for bootstrapping.
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func (db *DB) QuerySeeds(n int, maxAge time.Duration) []*Node {
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var (
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now = time.Now()
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nodes = make([]*Node, 0, n)
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it = db.lvl.NewIterator(nil, nil)
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id ID
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)
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defer it.Release()
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seek:
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for seeks := 0; len(nodes) < n && seeks < n*5; seeks++ {
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// Seek to a random entry. The first byte is incremented by a
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// random amount each time in order to increase the likelihood
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// of hitting all existing nodes in very small databases.
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ctr := id[0]
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rand.Read(id[:])
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id[0] = ctr + id[0]%16
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it.Seek(nodeKey(id))
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n := nextNode(it)
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if n == nil {
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id[0] = 0
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continue seek // iterator exhausted
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}
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if now.Sub(db.LastPongReceived(n.ID(), n.IP())) > maxAge {
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continue seek
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}
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for i := range nodes {
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if nodes[i].ID() == n.ID() {
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continue seek // duplicate
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}
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}
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nodes = append(nodes, n)
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}
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return nodes
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}
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// reads the next node record from the iterator, skipping over other
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// database entries.
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func nextNode(it iterator.Iterator) *Node {
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for end := false; !end; end = !it.Next() {
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id, rest := splitNodeKey(it.Key())
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if string(rest) != dbDiscoverRoot {
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continue
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}
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return mustDecodeNode(id[:], it.Value())
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}
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return nil
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}
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// close flushes and closes the database files.
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func (db *DB) Close() {
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close(db.quit)
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db.lvl.Close()
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}
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