142 lines
3.9 KiB
Go
142 lines
3.9 KiB
Go
// Copyright 2019 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 discover
|
|
|
|
import (
|
|
"crypto/ecdsa"
|
|
crand "crypto/rand"
|
|
"encoding/binary"
|
|
"math/rand"
|
|
"net"
|
|
"net/netip"
|
|
"sync"
|
|
"time"
|
|
|
|
"github.com/ethereum/go-ethereum/common/mclock"
|
|
"github.com/ethereum/go-ethereum/log"
|
|
"github.com/ethereum/go-ethereum/p2p/enode"
|
|
"github.com/ethereum/go-ethereum/p2p/enr"
|
|
"github.com/ethereum/go-ethereum/p2p/netutil"
|
|
)
|
|
|
|
// UDPConn is a network connection on which discovery can operate.
|
|
type UDPConn interface {
|
|
ReadFromUDPAddrPort(b []byte) (n int, addr netip.AddrPort, err error)
|
|
WriteToUDPAddrPort(b []byte, addr netip.AddrPort) (n int, err error)
|
|
Close() error
|
|
LocalAddr() net.Addr
|
|
}
|
|
|
|
// Config holds settings for the discovery listener.
|
|
type Config struct {
|
|
// These settings are required and configure the UDP listener:
|
|
PrivateKey *ecdsa.PrivateKey
|
|
|
|
// All remaining settings are optional.
|
|
|
|
// Packet handling configuration:
|
|
NetRestrict *netutil.Netlist // list of allowed IP networks
|
|
Unhandled chan<- ReadPacket // unhandled packets are sent on this channel
|
|
|
|
// Node table configuration:
|
|
Bootnodes []*enode.Node // list of bootstrap nodes
|
|
PingInterval time.Duration // speed of node liveness check
|
|
RefreshInterval time.Duration // used in bucket refresh
|
|
NoFindnodeLivenessCheck bool // turns off validation of table nodes in FINDNODE handler
|
|
|
|
// The options below are useful in very specific cases, like in unit tests.
|
|
V5ProtocolID *[6]byte
|
|
Log log.Logger // if set, log messages go here
|
|
ValidSchemes enr.IdentityScheme // allowed identity schemes
|
|
Clock mclock.Clock
|
|
}
|
|
|
|
func (cfg Config) withDefaults() Config {
|
|
// Node table configuration:
|
|
if cfg.PingInterval == 0 {
|
|
cfg.PingInterval = 3 * time.Second
|
|
}
|
|
if cfg.RefreshInterval == 0 {
|
|
cfg.RefreshInterval = 30 * time.Minute
|
|
}
|
|
|
|
// Debug/test settings:
|
|
if cfg.Log == nil {
|
|
cfg.Log = log.Root()
|
|
}
|
|
if cfg.ValidSchemes == nil {
|
|
cfg.ValidSchemes = enode.ValidSchemes
|
|
}
|
|
if cfg.Clock == nil {
|
|
cfg.Clock = mclock.System{}
|
|
}
|
|
return cfg
|
|
}
|
|
|
|
// ListenUDP starts listening for discovery packets on the given UDP socket.
|
|
func ListenUDP(c UDPConn, ln *enode.LocalNode, cfg Config) (*UDPv4, error) {
|
|
return ListenV4(c, ln, cfg)
|
|
}
|
|
|
|
// ReadPacket is a packet that couldn't be handled. Those packets are sent to the unhandled
|
|
// channel if configured.
|
|
type ReadPacket struct {
|
|
Data []byte
|
|
Addr netip.AddrPort
|
|
}
|
|
|
|
type randomSource interface {
|
|
Intn(int) int
|
|
Int63n(int64) int64
|
|
Shuffle(int, func(int, int))
|
|
}
|
|
|
|
// reseedingRandom is a random number generator that tracks when it was last re-seeded.
|
|
type reseedingRandom struct {
|
|
mu sync.Mutex
|
|
cur *rand.Rand
|
|
}
|
|
|
|
func (r *reseedingRandom) seed() {
|
|
var b [8]byte
|
|
crand.Read(b[:])
|
|
seed := binary.BigEndian.Uint64(b[:])
|
|
new := rand.New(rand.NewSource(int64(seed)))
|
|
|
|
r.mu.Lock()
|
|
r.cur = new
|
|
r.mu.Unlock()
|
|
}
|
|
|
|
func (r *reseedingRandom) Intn(n int) int {
|
|
r.mu.Lock()
|
|
defer r.mu.Unlock()
|
|
return r.cur.Intn(n)
|
|
}
|
|
|
|
func (r *reseedingRandom) Int63n(n int64) int64 {
|
|
r.mu.Lock()
|
|
defer r.mu.Unlock()
|
|
return r.cur.Int63n(n)
|
|
}
|
|
|
|
func (r *reseedingRandom) Shuffle(n int, swap func(i, j int)) {
|
|
r.mu.Lock()
|
|
defer r.mu.Unlock()
|
|
r.cur.Shuffle(n, swap)
|
|
}
|