mirror of https://github.com/ethereum/go-ethereum
Péter Szilágyi
10 years ago
parent
6def110c37
commit
8646365b42
@ -1,134 +0,0 @@ |
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// Contains the discovery cache, storing previously seen nodes to act as seed
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// servers during bootstrapping the network.
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package discover |
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import ( |
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"bytes" |
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"encoding/binary" |
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"net" |
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"os" |
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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/storage" |
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) |
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// Cache stores all nodes we know about.
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type Cache struct { |
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db *leveldb.DB |
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} |
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// Cache version to allow dumping old data if it changes.
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var cacheVersionKey = []byte("pv") |
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// NewMemoryCache creates a new in-memory peer cache without a persistent backend.
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func NewMemoryCache() (*Cache, 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 &Cache{db: db}, nil |
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} |
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// NewPersistentCache creates/opens a leveldb backed persistent peer cache, also
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// flushing its contents in case of a version mismatch.
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func NewPersistentCache(path string) (*Cache, error) { |
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// Try to open the cache, recovering any corruption
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db, err := leveldb.OpenFile(path, nil) |
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if _, iscorrupted := err.(leveldb.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, Version)] |
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blob, err := db.Get(cacheVersionKey, 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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err = db.Put(cacheVersionKey, currentVer, nil) |
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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 NewPersistentCache(path) |
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} |
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} |
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// Clean up in case of an error
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if err != nil { |
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db.Close() |
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return nil, err |
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} |
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return &Cache{db: db}, nil |
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} |
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// get retrieves a node with a given id from the seed da
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func (c *Cache) get(id NodeID) *Node { |
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blob, err := c.db.Get(id[:], nil) |
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if err != nil { |
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return nil |
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} |
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node := new(Node) |
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if err := rlp.DecodeBytes(blob, node); err != nil { |
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return nil |
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} |
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return node |
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} |
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// list retrieves a batch of nodes from the database.
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func (c *Cache) list(n int) []*Node { |
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it := c.db.NewIterator(nil, nil) |
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defer it.Release() |
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nodes := make([]*Node, 0, n) |
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for i := 0; i < n && it.Next(); i++ { |
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var id NodeID |
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copy(id[:], it.Key()) |
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if node := c.get(id); node != nil { |
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nodes = append(nodes, node) |
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} |
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} |
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return nodes |
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} |
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// update inserts - potentially overwriting - a node in the seed database.
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func (c *Cache) update(node *Node) error { |
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blob, err := rlp.EncodeToBytes(node) |
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if err != nil { |
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return err |
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} |
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return c.db.Put(node.ID[:], blob, nil) |
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} |
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// add inserts a new node into the seed database.
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func (c *Cache) add(id NodeID, addr *net.UDPAddr, tcpPort uint16) *Node { |
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node := &Node{ |
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ID: id, |
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IP: addr.IP, |
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DiscPort: addr.Port, |
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TCPPort: int(tcpPort), |
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} |
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c.update(node) |
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return node |
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} |
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// delete removes a node from the database.
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func (c *Cache) delete(id NodeID) error { |
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return c.db.Delete(id[:], nil) |
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} |
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// Close flushes and closes the database files.
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func (c *Cache) Close() { |
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c.db.Close() |
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} |
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@ -0,0 +1,233 @@ |
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// Contains the node database, storing previously seen nodes and any collected
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// metadata about them for QoS purposes.
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package discover |
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import ( |
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"bytes" |
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"encoding/binary" |
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"os" |
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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/storage" |
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) |
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// nodeDB stores all nodes we know about.
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type nodeDB struct { |
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lvl *leveldb.DB |
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} |
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// Schema layout for the node database
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var ( |
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nodeDBVersionKey = []byte("version") // Version of the database to flush if changes
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nodeDBStartupKey = []byte("startup") // Time when the node discovery started (seed selection)
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nodeDBItemPrefix = []byte("n:") // Identifier to prefix node entries with
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nodeDBDiscoverRoot = ":discover" |
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nodeDBDiscoverPing = nodeDBDiscoverRoot + ":lastping" |
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nodeDBDiscoverBond = nodeDBDiscoverRoot + ":lastbond" |
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) |
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// newNodeDB creates a new node database for storing and retrieving infos about
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// known peers in the network. If no path is given, an in-memory, temporary
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// database is constructed.
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func newNodeDB(path string) (*nodeDB, error) { |
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if path == "" { |
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return newMemoryNodeDB() |
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} |
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return newPersistentNodeDB(path) |
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} |
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// newMemoryNodeDB creates a new in-memory node database without a persistent
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// backend.
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func newMemoryNodeDB() (*nodeDB, 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 &nodeDB{lvl: db}, 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 newPersistentNodeDB(path string) (*nodeDB, error) { |
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// Try to open the cache, recovering any corruption
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db, err := leveldb.OpenFile(path, nil) |
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if _, iscorrupted := err.(leveldb.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, Version)] |
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blob, err := db.Get(nodeDBVersionKey, 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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err = db.Put(nodeDBVersionKey, currentVer, nil) |
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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 newPersistentNodeDB(path) |
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} |
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} |
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// Clean up in case of an error
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if err != nil { |
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db.Close() |
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return nil, err |
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} |
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return &nodeDB{lvl: db}, nil |
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} |
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// key generates the leveldb key-blob from a node id and its particular field of
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// interest.
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func (db *nodeDB) key(id NodeID, field string) []byte { |
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return append(nodeDBItemPrefix, append(id[:], field...)...) |
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} |
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// splitKey tries to split a database key into a node id and a field part.
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func (db *nodeDB) splitKey(key []byte) (id NodeID, field string) { |
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// If the key is not of a node, return it plainly
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if !bytes.HasPrefix(key, nodeDBItemPrefix) { |
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return NodeID{}, string(key) |
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} |
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// Otherwise split the id and field
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item := key[len(nodeDBItemPrefix):] |
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copy(id[:], item[:len(id)]) |
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field = string(item[len(id):]) |
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return id, field |
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} |
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// fetchTime retrieves a time instance (encoded as a unix timestamp) associated
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// with a particular database key.
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func (db *nodeDB) fetchTime(key []byte) time.Time { |
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blob, err := db.lvl.Get(key, nil) |
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if err != nil { |
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return time.Time{} |
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} |
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var unix int64 |
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if err := rlp.DecodeBytes(blob, &unix); err != nil { |
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return time.Time{} |
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} |
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return time.Unix(unix, 0) |
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} |
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// storeTime update a specific database entry to the current time instance as a
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// unix timestamp.
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func (db *nodeDB) storeTime(key []byte, instance time.Time) error { |
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blob, err := rlp.EncodeToBytes(instance.Unix()) |
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if err != nil { |
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return err |
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} |
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return db.lvl.Put(key, blob, nil) |
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} |
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// startup retrieves the time instance when the bootstrapping last begun. Its
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// purpose is to prevent contacting potential seed nodes multiple times in the
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// same boot cycle.
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func (db *nodeDB) startup() time.Time { |
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return db.fetchTime(nodeDBStartupKey) |
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} |
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// updateStartup updates the bootstrap initiation time to the one specified.
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func (db *nodeDB) updateStartup(instance time.Time) error { |
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return db.storeTime(nodeDBStartupKey, instance) |
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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 *nodeDB) node(id NodeID) *Node { |
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blob, err := db.lvl.Get(db.key(id, nodeDBDiscoverRoot), nil) |
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if err != nil { |
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return nil |
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} |
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node := new(Node) |
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if err := rlp.DecodeBytes(blob, node); err != nil { |
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return nil |
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} |
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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 *nodeDB) updateNode(node *Node) error { |
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blob, err := rlp.EncodeToBytes(node) |
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if err != nil { |
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return err |
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} |
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return db.lvl.Put(db.key(node.ID, nodeDBDiscoverRoot), blob, nil) |
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} |
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// lastPing retrieves the time of the last ping packet send to a remote node,
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// requesting binding.
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func (db *nodeDB) lastPing(id NodeID) time.Time { |
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return db.fetchTime(db.key(id, nodeDBDiscoverPing)) |
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} |
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// updateLastPing updates the last time we tried contacting a remote node.
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func (db *nodeDB) updateLastPing(id NodeID, instance time.Time) error { |
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return db.storeTime(db.key(id, nodeDBDiscoverPing), instance) |
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} |
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// lastBond retrieves the time of the last successful bonding with a remote node.
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func (db *nodeDB) lastBond(id NodeID) time.Time { |
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return db.fetchTime(db.key(id, nodeDBDiscoverBond)) |
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} |
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// updateLastBond updates the last time we successfully bound to a remote node.
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func (db *nodeDB) updateLastBond(id NodeID, instance time.Time) error { |
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return db.storeTime(db.key(id, nodeDBDiscoverBond), instance) |
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} |
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// querySeeds retrieves a batch of nodes to be used as potential seed servers
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// during bootstrapping the node into the network.
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//
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// Ideal seeds are the most recently seen nodes (highest probability to be still
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// alive), but yet untried. However, since leveldb only supports dumb iteration
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// we will instead start pulling in potential seeds that haven't been yet pinged
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// since the start of the boot procedure.
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//
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// If the database runs out of potential seeds, we restart the startup counter
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// and start iterating over the peers again.
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func (db *nodeDB) querySeeds(n int) []*Node { |
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startup := db.startup() |
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it := db.lvl.NewIterator(nil, nil) |
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defer it.Release() |
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nodes := make([]*Node, 0, n) |
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for len(nodes) < n && it.Next() { |
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// Iterate until a discovery node is found
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id, field := db.splitKey(it.Key()) |
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if field != nodeDBDiscoverRoot { |
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continue |
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} |
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// Retrieve the last ping time, and if older than startup, query
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lastPing := db.lastPing(id) |
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if lastPing.Before(startup) { |
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if node := db.node(id); node != nil { |
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nodes = append(nodes, node) |
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} |
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} |
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} |
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// Reset the startup time if no seeds were found
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if len(nodes) == 0 { |
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db.updateStartup(time.Now()) |
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} |
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return nodes |
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} |
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// close flushes and closes the database files.
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func (db *nodeDB) close() { |
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db.lvl.Close() |
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} |
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