// Copyright 2018 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package enode
import (
"crypto/ecdsa"
"fmt"
"net"
"reflect"
"strconv"
"sync"
"sync/atomic"
"time"
"github.com/tangerine-network/go-tangerine/log"
"github.com/tangerine-network/go-tangerine/p2p/enr"
"github.com/tangerine-network/go-tangerine/p2p/netutil"
)
const (
// IP tracker configuration
iptrackMinStatements = 10
iptrackWindow = 5 * time.Minute
iptrackContactWindow = 10 * time.Minute
)
// LocalNode produces the signed node record of a local node, i.e. a node run in the
// current process. Setting ENR entries via the Set method updates the record. A new version
// of the record is signed on demand when the Node method is called.
type LocalNode struct {
cur atomic.Value // holds a non-nil node pointer while the record is up-to-date.
id ID
key *ecdsa.PrivateKey
db *DB
// everything below is protected by a lock
mu sync.Mutex
seq uint64
entries map[string]enr.Entry
udpTrack *netutil.IPTracker // predicts external UDP endpoint
staticIP net.IP
fallbackIP net.IP
fallbackUDP int
}
// NewLocalNode creates a local node.
func NewLocalNode(db *DB, key *ecdsa.PrivateKey) *LocalNode {
ln := &LocalNode{
id: PubkeyToIDV4(&key.PublicKey),
db: db,
key: key,
udpTrack: netutil.NewIPTracker(iptrackWindow, iptrackContactWindow, iptrackMinStatements),
entries: make(map[string]enr.Entry),
}
ln.seq = db.localSeq(ln.id)
ln.invalidate()
return ln
}
// Database returns the node database associated with the local node.
func (ln *LocalNode) Database() *DB {
return ln.db
}
// Node returns the current version of the local node record.
func (ln *LocalNode) Node() *Node {
n := ln.cur.Load().(*Node)
if n != nil {
return n
}
// Record was invalidated, sign a new copy.
ln.mu.Lock()
defer ln.mu.Unlock()
ln.sign()
return ln.cur.Load().(*Node)
}
// ID returns the local node ID.
func (ln *LocalNode) ID() ID {
return ln.id
}
// Set puts the given entry into the local record, overwriting
// any existing value.
func (ln *LocalNode) Set(e enr.Entry) {
ln.mu.Lock()
defer ln.mu.Unlock()
ln.set(e)
}
func (ln *LocalNode) set(e enr.Entry) {
val, exists := ln.entries[e.ENRKey()]
if !exists || !reflect.DeepEqual(val, e) {
ln.entries[e.ENRKey()] = e
ln.invalidate()
}
}
// Delete removes the given entry from the local record.
func (ln *LocalNode) Delete(e enr.Entry) {
ln.mu.Lock()
defer ln.mu.Unlock()
ln.delete(e)
}
func (ln *LocalNode) delete(e enr.Entry) {
_, exists := ln.entries[e.ENRKey()]
if exists {
delete(ln.entries, e.ENRKey())
ln.invalidate()
}
}
// SetStaticIP sets the local IP to the given one unconditionally.
// This disables endpoint prediction.
func (ln *LocalNode) SetStaticIP(ip net.IP) {
ln.mu.Lock()
defer ln.mu.Unlock()
ln.staticIP = ip
ln.updateEndpoints()
}
// SetFallbackIP sets the last-resort IP address. This address is used
// if no endpoint prediction can be made and no static IP is set.
func (ln *LocalNode) SetFallbackIP(ip net.IP) {
ln.mu.Lock()
defer ln.mu.Unlock()
ln.fallbackIP = ip
ln.updateEndpoints()
}
// SetFallbackUDP sets the last-resort UDP port. This port is used
// if no endpoint prediction can be made.
func (ln *LocalNode) SetFallbackUDP(port int) {
ln.mu.Lock()
defer ln.mu.Unlock()
ln.fallbackUDP = port
ln.updateEndpoints()
}
// UDPEndpointStatement should be called whenever a statement about the local node's
// UDP endpoint is received. It feeds the local endpoint predictor.
func (ln *LocalNode) UDPEndpointStatement(fromaddr, endpoint *net.UDPAddr) {
ln.mu.Lock()
defer ln.mu.Unlock()
ln.udpTrack.AddStatement(fromaddr.String(), endpoint.String())
ln.updateEndpoints()
}
// UDPContact should be called whenever the local node has announced itself to another node
// via UDP. It feeds the local endpoint predictor.
func (ln *LocalNode) UDPContact(toaddr *net.UDPAddr) {
ln.mu.Lock()
defer ln.mu.Unlock()
ln.udpTrack.AddContact(toaddr.String())
ln.updateEndpoints()
}
func (ln *LocalNode) updateEndpoints() {
// Determine the endpoints.
newIP := ln.fallbackIP
newUDP := ln.fallbackUDP
if ln.staticIP != nil {
newIP = ln.staticIP
} else if ip, port := predictAddr(ln.udpTrack); ip != nil {
newIP = ip
newUDP = port
}
// Update the record.
if newIP != nil && !newIP.IsUnspecified() {
ln.set(enr.IP(newIP))
if newUDP != 0 {
ln.set(enr.UDP(newUDP))
} else {
ln.delete(enr.UDP(0))
}
} else {
ln.delete(enr.IP{})
}
}
// predictAddr wraps IPTracker.PredictEndpoint, converting from its string-based
// endpoint representation to IP and port types.
func predictAddr(t *netutil.IPTracker) (net.IP, int) {
ep := t.PredictEndpoint()
if ep == "" {
return nil, 0
}
ipString, portString, _ := net.SplitHostPort(ep)
ip := net.ParseIP(ipString)
port, _ := strconv.Atoi(portString)
return ip, port
}
func (ln *LocalNode) invalidate() {
ln.cur.Store((*Node)(nil))
}
func (ln *LocalNode) sign() {
if n := ln.cur.Load().(*Node); n != nil {
return // no changes
}
var r enr.Record
for _, e := range ln.entries {
r.Set(e)
}
ln.bumpSeq()
r.SetSeq(ln.seq)
if err := SignV4(&r, ln.key); err != nil {
panic(fmt.Errorf("enode: can't sign record: %v", err))
}
n, err := New(ValidSchemes, &r)
if err != nil {
panic(fmt.Errorf("enode: can't verify local record: %v", err))
}
ln.cur.Store(n)
log.Info("New local node record", "seq", ln.seq, "id", n.ID(), "ip", n.IP(), "udp", n.UDP(), "tcp", n.TCP())
}
func (ln *LocalNode) bumpSeq() {
ln.seq++
ln.db.storeLocalSeq(ln.id, ln.seq)
}
