mirror of
https://gitlab.com/pulsechaincom/go-pulse.git
synced 2024-12-24 12:27:17 +00:00
138f0d7494
Co-authored-by: Felix Lange <fjl@twurst.com>
788 lines
24 KiB
Go
788 lines
24 KiB
Go
// Copyright 2019 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 discover
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import (
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"bytes"
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"container/list"
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"context"
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"crypto/ecdsa"
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crand "crypto/rand"
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"errors"
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"fmt"
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"io"
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"net"
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"sync"
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"time"
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"github.com/ethereum/go-ethereum/crypto"
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"github.com/ethereum/go-ethereum/log"
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"github.com/ethereum/go-ethereum/p2p/discover/v4wire"
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"github.com/ethereum/go-ethereum/p2p/enode"
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"github.com/ethereum/go-ethereum/p2p/netutil"
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)
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// Errors
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var (
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errExpired = errors.New("expired")
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errUnsolicitedReply = errors.New("unsolicited reply")
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errUnknownNode = errors.New("unknown node")
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errTimeout = errors.New("RPC timeout")
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errClockWarp = errors.New("reply deadline too far in the future")
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errClosed = errors.New("socket closed")
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errLowPort = errors.New("low port")
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)
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const (
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respTimeout = 500 * time.Millisecond
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expiration = 20 * time.Second
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bondExpiration = 24 * time.Hour
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maxFindnodeFailures = 5 // nodes exceeding this limit are dropped
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ntpFailureThreshold = 32 // Continuous timeouts after which to check NTP
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ntpWarningCooldown = 10 * time.Minute // Minimum amount of time to pass before repeating NTP warning
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driftThreshold = 10 * time.Second // Allowed clock drift before warning user
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// Discovery packets are defined to be no larger than 1280 bytes.
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// Packets larger than this size will be cut at the end and treated
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// as invalid because their hash won't match.
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maxPacketSize = 1280
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)
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// UDPv4 implements the v4 wire protocol.
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type UDPv4 struct {
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conn UDPConn
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log log.Logger
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netrestrict *netutil.Netlist
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priv *ecdsa.PrivateKey
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localNode *enode.LocalNode
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db *enode.DB
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tab *Table
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closeOnce sync.Once
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wg sync.WaitGroup
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addReplyMatcher chan *replyMatcher
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gotreply chan reply
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closeCtx context.Context
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cancelCloseCtx context.CancelFunc
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}
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// replyMatcher represents a pending reply.
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//
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// Some implementations of the protocol wish to send more than one
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// reply packet to findnode. In general, any neighbors packet cannot
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// be matched up with a specific findnode packet.
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//
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// Our implementation handles this by storing a callback function for
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// each pending reply. Incoming packets from a node are dispatched
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// to all callback functions for that node.
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type replyMatcher struct {
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// these fields must match in the reply.
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from enode.ID
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ip net.IP
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ptype byte
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// time when the request must complete
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deadline time.Time
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// callback is called when a matching reply arrives. If it returns matched == true, the
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// reply was acceptable. The second return value indicates whether the callback should
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// be removed from the pending reply queue. If it returns false, the reply is considered
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// incomplete and the callback will be invoked again for the next matching reply.
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callback replyMatchFunc
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// errc receives nil when the callback indicates completion or an
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// error if no further reply is received within the timeout.
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errc chan error
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// reply contains the most recent reply. This field is safe for reading after errc has
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// received a value.
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reply v4wire.Packet
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}
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type replyMatchFunc func(v4wire.Packet) (matched bool, requestDone bool)
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// reply is a reply packet from a certain node.
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type reply struct {
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from enode.ID
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ip net.IP
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data v4wire.Packet
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// loop indicates whether there was
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// a matching request by sending on this channel.
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matched chan<- bool
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}
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func ListenV4(c UDPConn, ln *enode.LocalNode, cfg Config) (*UDPv4, error) {
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cfg = cfg.withDefaults()
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closeCtx, cancel := context.WithCancel(context.Background())
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t := &UDPv4{
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conn: c,
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priv: cfg.PrivateKey,
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netrestrict: cfg.NetRestrict,
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localNode: ln,
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db: ln.Database(),
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gotreply: make(chan reply),
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addReplyMatcher: make(chan *replyMatcher),
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closeCtx: closeCtx,
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cancelCloseCtx: cancel,
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log: cfg.Log,
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}
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tab, err := newTable(t, ln.Database(), cfg.Bootnodes, t.log)
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if err != nil {
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return nil, err
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}
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t.tab = tab
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go tab.loop()
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t.wg.Add(2)
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go t.loop()
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go t.readLoop(cfg.Unhandled)
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return t, nil
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}
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// Self returns the local node.
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func (t *UDPv4) Self() *enode.Node {
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return t.localNode.Node()
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}
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// Close shuts down the socket and aborts any running queries.
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func (t *UDPv4) Close() {
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t.closeOnce.Do(func() {
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t.cancelCloseCtx()
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t.conn.Close()
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t.wg.Wait()
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t.tab.close()
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})
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}
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// Resolve searches for a specific node with the given ID and tries to get the most recent
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// version of the node record for it. It returns n if the node could not be resolved.
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func (t *UDPv4) Resolve(n *enode.Node) *enode.Node {
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// Try asking directly. This works if the node is still responding on the endpoint we have.
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if rn, err := t.RequestENR(n); err == nil {
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return rn
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}
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// Check table for the ID, we might have a newer version there.
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if intable := t.tab.getNode(n.ID()); intable != nil && intable.Seq() > n.Seq() {
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n = intable
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if rn, err := t.RequestENR(n); err == nil {
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return rn
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}
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}
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// Otherwise perform a network lookup.
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var key enode.Secp256k1
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if n.Load(&key) != nil {
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return n // no secp256k1 key
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}
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result := t.LookupPubkey((*ecdsa.PublicKey)(&key))
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for _, rn := range result {
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if rn.ID() == n.ID() {
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if rn, err := t.RequestENR(rn); err == nil {
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return rn
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}
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}
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}
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return n
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}
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func (t *UDPv4) ourEndpoint() v4wire.Endpoint {
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n := t.Self()
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a := &net.UDPAddr{IP: n.IP(), Port: n.UDP()}
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return v4wire.NewEndpoint(a, uint16(n.TCP()))
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}
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// Ping sends a ping message to the given node.
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func (t *UDPv4) Ping(n *enode.Node) error {
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_, err := t.ping(n)
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return err
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}
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// ping sends a ping message to the given node and waits for a reply.
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func (t *UDPv4) ping(n *enode.Node) (seq uint64, err error) {
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rm := t.sendPing(n.ID(), &net.UDPAddr{IP: n.IP(), Port: n.UDP()}, nil)
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if err = <-rm.errc; err == nil {
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seq = rm.reply.(*v4wire.Pong).ENRSeq
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}
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return seq, err
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}
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// sendPing sends a ping message to the given node and invokes the callback
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// when the reply arrives.
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func (t *UDPv4) sendPing(toid enode.ID, toaddr *net.UDPAddr, callback func()) *replyMatcher {
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req := t.makePing(toaddr)
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packet, hash, err := v4wire.Encode(t.priv, req)
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if err != nil {
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errc := make(chan error, 1)
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errc <- err
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return &replyMatcher{errc: errc}
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}
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// Add a matcher for the reply to the pending reply queue. Pongs are matched if they
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// reference the ping we're about to send.
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rm := t.pending(toid, toaddr.IP, v4wire.PongPacket, func(p v4wire.Packet) (matched bool, requestDone bool) {
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matched = bytes.Equal(p.(*v4wire.Pong).ReplyTok, hash)
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if matched && callback != nil {
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callback()
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}
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return matched, matched
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})
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// Send the packet.
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t.localNode.UDPContact(toaddr)
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t.write(toaddr, toid, req.Name(), packet)
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return rm
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}
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func (t *UDPv4) makePing(toaddr *net.UDPAddr) *v4wire.Ping {
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return &v4wire.Ping{
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Version: 4,
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From: t.ourEndpoint(),
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To: v4wire.NewEndpoint(toaddr, 0),
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Expiration: uint64(time.Now().Add(expiration).Unix()),
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ENRSeq: t.localNode.Node().Seq(),
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}
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}
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// LookupPubkey finds the closest nodes to the given public key.
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func (t *UDPv4) LookupPubkey(key *ecdsa.PublicKey) []*enode.Node {
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if t.tab.len() == 0 {
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// All nodes were dropped, refresh. The very first query will hit this
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// case and run the bootstrapping logic.
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<-t.tab.refresh()
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}
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return t.newLookup(t.closeCtx, encodePubkey(key)).run()
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}
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// RandomNodes is an iterator yielding nodes from a random walk of the DHT.
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func (t *UDPv4) RandomNodes() enode.Iterator {
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return newLookupIterator(t.closeCtx, t.newRandomLookup)
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}
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// lookupRandom implements transport.
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func (t *UDPv4) lookupRandom() []*enode.Node {
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return t.newRandomLookup(t.closeCtx).run()
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}
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// lookupSelf implements transport.
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func (t *UDPv4) lookupSelf() []*enode.Node {
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return t.newLookup(t.closeCtx, encodePubkey(&t.priv.PublicKey)).run()
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}
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func (t *UDPv4) newRandomLookup(ctx context.Context) *lookup {
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var target encPubkey
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crand.Read(target[:])
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return t.newLookup(ctx, target)
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}
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func (t *UDPv4) newLookup(ctx context.Context, targetKey encPubkey) *lookup {
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target := enode.ID(crypto.Keccak256Hash(targetKey[:]))
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ekey := v4wire.Pubkey(targetKey)
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it := newLookup(ctx, t.tab, target, func(n *node) ([]*node, error) {
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return t.findnode(n.ID(), n.addr(), ekey)
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})
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return it
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}
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// findnode sends a findnode request to the given node and waits until
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// the node has sent up to k neighbors.
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func (t *UDPv4) findnode(toid enode.ID, toaddr *net.UDPAddr, target v4wire.Pubkey) ([]*node, error) {
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t.ensureBond(toid, toaddr)
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// Add a matcher for 'neighbours' replies to the pending reply queue. The matcher is
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// active until enough nodes have been received.
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nodes := make([]*node, 0, bucketSize)
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nreceived := 0
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rm := t.pending(toid, toaddr.IP, v4wire.NeighborsPacket, func(r v4wire.Packet) (matched bool, requestDone bool) {
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reply := r.(*v4wire.Neighbors)
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for _, rn := range reply.Nodes {
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nreceived++
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n, err := t.nodeFromRPC(toaddr, rn)
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if err != nil {
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t.log.Trace("Invalid neighbor node received", "ip", rn.IP, "addr", toaddr, "err", err)
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continue
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}
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nodes = append(nodes, n)
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}
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return true, nreceived >= bucketSize
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})
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t.send(toaddr, toid, &v4wire.Findnode{
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Target: target,
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Expiration: uint64(time.Now().Add(expiration).Unix()),
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})
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// Ensure that callers don't see a timeout if the node actually responded. Since
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// findnode can receive more than one neighbors response, the reply matcher will be
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// active until the remote node sends enough nodes. If the remote end doesn't have
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// enough nodes the reply matcher will time out waiting for the second reply, but
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// there's no need for an error in that case.
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err := <-rm.errc
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if errors.Is(err, errTimeout) && rm.reply != nil {
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err = nil
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}
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return nodes, err
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}
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// RequestENR sends enrRequest to the given node and waits for a response.
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func (t *UDPv4) RequestENR(n *enode.Node) (*enode.Node, error) {
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addr := &net.UDPAddr{IP: n.IP(), Port: n.UDP()}
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t.ensureBond(n.ID(), addr)
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req := &v4wire.ENRRequest{
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Expiration: uint64(time.Now().Add(expiration).Unix()),
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}
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packet, hash, err := v4wire.Encode(t.priv, req)
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if err != nil {
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return nil, err
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}
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// Add a matcher for the reply to the pending reply queue. Responses are matched if
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// they reference the request we're about to send.
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rm := t.pending(n.ID(), addr.IP, v4wire.ENRResponsePacket, func(r v4wire.Packet) (matched bool, requestDone bool) {
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matched = bytes.Equal(r.(*v4wire.ENRResponse).ReplyTok, hash)
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return matched, matched
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})
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// Send the packet and wait for the reply.
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t.write(addr, n.ID(), req.Name(), packet)
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if err := <-rm.errc; err != nil {
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return nil, err
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}
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// Verify the response record.
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respN, err := enode.New(enode.ValidSchemes, &rm.reply.(*v4wire.ENRResponse).Record)
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if err != nil {
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return nil, err
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}
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if respN.ID() != n.ID() {
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return nil, fmt.Errorf("invalid ID in response record")
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}
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if respN.Seq() < n.Seq() {
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return n, nil // response record is older
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}
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if err := netutil.CheckRelayIP(addr.IP, respN.IP()); err != nil {
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return nil, fmt.Errorf("invalid IP in response record: %v", err)
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}
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return respN, nil
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}
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// pending adds a reply matcher to the pending reply queue.
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// see the documentation of type replyMatcher for a detailed explanation.
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func (t *UDPv4) pending(id enode.ID, ip net.IP, ptype byte, callback replyMatchFunc) *replyMatcher {
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ch := make(chan error, 1)
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p := &replyMatcher{from: id, ip: ip, ptype: ptype, callback: callback, errc: ch}
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select {
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case t.addReplyMatcher <- p:
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// loop will handle it
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case <-t.closeCtx.Done():
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ch <- errClosed
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}
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return p
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}
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// handleReply dispatches a reply packet, invoking reply matchers. It returns
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// whether any matcher considered the packet acceptable.
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func (t *UDPv4) handleReply(from enode.ID, fromIP net.IP, req v4wire.Packet) bool {
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matched := make(chan bool, 1)
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select {
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case t.gotreply <- reply{from, fromIP, req, matched}:
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// loop will handle it
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return <-matched
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case <-t.closeCtx.Done():
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return false
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}
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}
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// loop runs in its own goroutine. it keeps track of
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// the refresh timer and the pending reply queue.
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func (t *UDPv4) loop() {
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defer t.wg.Done()
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var (
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plist = list.New()
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timeout = time.NewTimer(0)
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nextTimeout *replyMatcher // head of plist when timeout was last reset
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contTimeouts = 0 // number of continuous timeouts to do NTP checks
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ntpWarnTime = time.Unix(0, 0)
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)
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<-timeout.C // ignore first timeout
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defer timeout.Stop()
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resetTimeout := func() {
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if plist.Front() == nil || nextTimeout == plist.Front().Value {
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return
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}
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// Start the timer so it fires when the next pending reply has expired.
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now := time.Now()
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for el := plist.Front(); el != nil; el = el.Next() {
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nextTimeout = el.Value.(*replyMatcher)
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if dist := nextTimeout.deadline.Sub(now); dist < 2*respTimeout {
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timeout.Reset(dist)
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return
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}
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// Remove pending replies whose deadline is too far in the
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// future. These can occur if the system clock jumped
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// backwards after the deadline was assigned.
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nextTimeout.errc <- errClockWarp
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plist.Remove(el)
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}
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nextTimeout = nil
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timeout.Stop()
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}
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for {
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resetTimeout()
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select {
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case <-t.closeCtx.Done():
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for el := plist.Front(); el != nil; el = el.Next() {
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el.Value.(*replyMatcher).errc <- errClosed
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}
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return
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case p := <-t.addReplyMatcher:
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p.deadline = time.Now().Add(respTimeout)
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plist.PushBack(p)
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case r := <-t.gotreply:
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var matched bool // whether any replyMatcher considered the reply acceptable.
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for el := plist.Front(); el != nil; el = el.Next() {
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p := el.Value.(*replyMatcher)
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if p.from == r.from && p.ptype == r.data.Kind() && p.ip.Equal(r.ip) {
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ok, requestDone := p.callback(r.data)
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matched = matched || ok
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p.reply = r.data
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// Remove the matcher if callback indicates that all replies have been received.
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if requestDone {
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p.errc <- nil
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plist.Remove(el)
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}
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// Reset the continuous timeout counter (time drift detection)
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contTimeouts = 0
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}
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}
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r.matched <- matched
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case now := <-timeout.C:
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nextTimeout = nil
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// Notify and remove callbacks whose deadline is in the past.
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for el := plist.Front(); el != nil; el = el.Next() {
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p := el.Value.(*replyMatcher)
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if now.After(p.deadline) || now.Equal(p.deadline) {
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p.errc <- errTimeout
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plist.Remove(el)
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contTimeouts++
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}
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}
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// If we've accumulated too many timeouts, do an NTP time sync check
|
|
if contTimeouts > ntpFailureThreshold {
|
|
if time.Since(ntpWarnTime) >= ntpWarningCooldown {
|
|
ntpWarnTime = time.Now()
|
|
go checkClockDrift()
|
|
}
|
|
contTimeouts = 0
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
func (t *UDPv4) send(toaddr *net.UDPAddr, toid enode.ID, req v4wire.Packet) ([]byte, error) {
|
|
packet, hash, err := v4wire.Encode(t.priv, req)
|
|
if err != nil {
|
|
return hash, err
|
|
}
|
|
return hash, t.write(toaddr, toid, req.Name(), packet)
|
|
}
|
|
|
|
func (t *UDPv4) write(toaddr *net.UDPAddr, toid enode.ID, what string, packet []byte) error {
|
|
_, err := t.conn.WriteToUDP(packet, toaddr)
|
|
t.log.Trace(">> "+what, "id", toid, "addr", toaddr, "err", err)
|
|
return err
|
|
}
|
|
|
|
// readLoop runs in its own goroutine. it handles incoming UDP packets.
|
|
func (t *UDPv4) readLoop(unhandled chan<- ReadPacket) {
|
|
defer t.wg.Done()
|
|
if unhandled != nil {
|
|
defer close(unhandled)
|
|
}
|
|
|
|
buf := make([]byte, maxPacketSize)
|
|
for {
|
|
nbytes, from, err := t.conn.ReadFromUDP(buf)
|
|
if netutil.IsTemporaryError(err) {
|
|
// Ignore temporary read errors.
|
|
t.log.Debug("Temporary UDP read error", "err", err)
|
|
continue
|
|
} else if err != nil {
|
|
// Shut down the loop for permament errors.
|
|
if !errors.Is(err, io.EOF) {
|
|
t.log.Debug("UDP read error", "err", err)
|
|
}
|
|
return
|
|
}
|
|
if t.handlePacket(from, buf[:nbytes]) != nil && unhandled != nil {
|
|
select {
|
|
case unhandled <- ReadPacket{buf[:nbytes], from}:
|
|
default:
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
func (t *UDPv4) handlePacket(from *net.UDPAddr, buf []byte) error {
|
|
rawpacket, fromKey, hash, err := v4wire.Decode(buf)
|
|
if err != nil {
|
|
t.log.Debug("Bad discv4 packet", "addr", from, "err", err)
|
|
return err
|
|
}
|
|
packet := t.wrapPacket(rawpacket)
|
|
fromID := fromKey.ID()
|
|
if err == nil && packet.preverify != nil {
|
|
err = packet.preverify(packet, from, fromID, fromKey)
|
|
}
|
|
t.log.Trace("<< "+packet.Name(), "id", fromID, "addr", from, "err", err)
|
|
if err == nil && packet.handle != nil {
|
|
packet.handle(packet, from, fromID, hash)
|
|
}
|
|
return err
|
|
}
|
|
|
|
// checkBond checks if the given node has a recent enough endpoint proof.
|
|
func (t *UDPv4) checkBond(id enode.ID, ip net.IP) bool {
|
|
return time.Since(t.db.LastPongReceived(id, ip)) < bondExpiration
|
|
}
|
|
|
|
// ensureBond solicits a ping from a node if we haven't seen a ping from it for a while.
|
|
// This ensures there is a valid endpoint proof on the remote end.
|
|
func (t *UDPv4) ensureBond(toid enode.ID, toaddr *net.UDPAddr) {
|
|
tooOld := time.Since(t.db.LastPingReceived(toid, toaddr.IP)) > bondExpiration
|
|
if tooOld || t.db.FindFails(toid, toaddr.IP) > maxFindnodeFailures {
|
|
rm := t.sendPing(toid, toaddr, nil)
|
|
<-rm.errc
|
|
// Wait for them to ping back and process our pong.
|
|
time.Sleep(respTimeout)
|
|
}
|
|
}
|
|
|
|
func (t *UDPv4) nodeFromRPC(sender *net.UDPAddr, rn v4wire.Node) (*node, error) {
|
|
if rn.UDP <= 1024 {
|
|
return nil, errLowPort
|
|
}
|
|
if err := netutil.CheckRelayIP(sender.IP, rn.IP); err != nil {
|
|
return nil, err
|
|
}
|
|
if t.netrestrict != nil && !t.netrestrict.Contains(rn.IP) {
|
|
return nil, errors.New("not contained in netrestrict list")
|
|
}
|
|
key, err := v4wire.DecodePubkey(crypto.S256(), rn.ID)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
n := wrapNode(enode.NewV4(key, rn.IP, int(rn.TCP), int(rn.UDP)))
|
|
err = n.ValidateComplete()
|
|
return n, err
|
|
}
|
|
|
|
func nodeToRPC(n *node) v4wire.Node {
|
|
var key ecdsa.PublicKey
|
|
var ekey v4wire.Pubkey
|
|
if err := n.Load((*enode.Secp256k1)(&key)); err == nil {
|
|
ekey = v4wire.EncodePubkey(&key)
|
|
}
|
|
return v4wire.Node{ID: ekey, IP: n.IP(), UDP: uint16(n.UDP()), TCP: uint16(n.TCP())}
|
|
}
|
|
|
|
// wrapPacket returns the handler functions applicable to a packet.
|
|
func (t *UDPv4) wrapPacket(p v4wire.Packet) *packetHandlerV4 {
|
|
var h packetHandlerV4
|
|
h.Packet = p
|
|
switch p.(type) {
|
|
case *v4wire.Ping:
|
|
h.preverify = t.verifyPing
|
|
h.handle = t.handlePing
|
|
case *v4wire.Pong:
|
|
h.preverify = t.verifyPong
|
|
case *v4wire.Findnode:
|
|
h.preverify = t.verifyFindnode
|
|
h.handle = t.handleFindnode
|
|
case *v4wire.Neighbors:
|
|
h.preverify = t.verifyNeighbors
|
|
case *v4wire.ENRRequest:
|
|
h.preverify = t.verifyENRRequest
|
|
h.handle = t.handleENRRequest
|
|
case *v4wire.ENRResponse:
|
|
h.preverify = t.verifyENRResponse
|
|
}
|
|
return &h
|
|
}
|
|
|
|
// packetHandlerV4 wraps a packet with handler functions.
|
|
type packetHandlerV4 struct {
|
|
v4wire.Packet
|
|
senderKey *ecdsa.PublicKey // used for ping
|
|
|
|
// preverify checks whether the packet is valid and should be handled at all.
|
|
preverify func(p *packetHandlerV4, from *net.UDPAddr, fromID enode.ID, fromKey v4wire.Pubkey) error
|
|
// handle handles the packet.
|
|
handle func(req *packetHandlerV4, from *net.UDPAddr, fromID enode.ID, mac []byte)
|
|
}
|
|
|
|
// PING/v4
|
|
|
|
func (t *UDPv4) verifyPing(h *packetHandlerV4, from *net.UDPAddr, fromID enode.ID, fromKey v4wire.Pubkey) error {
|
|
req := h.Packet.(*v4wire.Ping)
|
|
|
|
senderKey, err := v4wire.DecodePubkey(crypto.S256(), fromKey)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if v4wire.Expired(req.Expiration) {
|
|
return errExpired
|
|
}
|
|
h.senderKey = senderKey
|
|
return nil
|
|
}
|
|
|
|
func (t *UDPv4) handlePing(h *packetHandlerV4, from *net.UDPAddr, fromID enode.ID, mac []byte) {
|
|
req := h.Packet.(*v4wire.Ping)
|
|
|
|
// Reply.
|
|
t.send(from, fromID, &v4wire.Pong{
|
|
To: v4wire.NewEndpoint(from, req.From.TCP),
|
|
ReplyTok: mac,
|
|
Expiration: uint64(time.Now().Add(expiration).Unix()),
|
|
ENRSeq: t.localNode.Node().Seq(),
|
|
})
|
|
|
|
// Ping back if our last pong on file is too far in the past.
|
|
n := wrapNode(enode.NewV4(h.senderKey, from.IP, int(req.From.TCP), from.Port))
|
|
if time.Since(t.db.LastPongReceived(n.ID(), from.IP)) > bondExpiration {
|
|
t.sendPing(fromID, from, func() {
|
|
t.tab.addVerifiedNode(n)
|
|
})
|
|
} else {
|
|
t.tab.addVerifiedNode(n)
|
|
}
|
|
|
|
// Update node database and endpoint predictor.
|
|
t.db.UpdateLastPingReceived(n.ID(), from.IP, time.Now())
|
|
t.localNode.UDPEndpointStatement(from, &net.UDPAddr{IP: req.To.IP, Port: int(req.To.UDP)})
|
|
}
|
|
|
|
// PONG/v4
|
|
|
|
func (t *UDPv4) verifyPong(h *packetHandlerV4, from *net.UDPAddr, fromID enode.ID, fromKey v4wire.Pubkey) error {
|
|
req := h.Packet.(*v4wire.Pong)
|
|
|
|
if v4wire.Expired(req.Expiration) {
|
|
return errExpired
|
|
}
|
|
if !t.handleReply(fromID, from.IP, req) {
|
|
return errUnsolicitedReply
|
|
}
|
|
t.localNode.UDPEndpointStatement(from, &net.UDPAddr{IP: req.To.IP, Port: int(req.To.UDP)})
|
|
t.db.UpdateLastPongReceived(fromID, from.IP, time.Now())
|
|
return nil
|
|
}
|
|
|
|
// FINDNODE/v4
|
|
|
|
func (t *UDPv4) verifyFindnode(h *packetHandlerV4, from *net.UDPAddr, fromID enode.ID, fromKey v4wire.Pubkey) error {
|
|
req := h.Packet.(*v4wire.Findnode)
|
|
|
|
if v4wire.Expired(req.Expiration) {
|
|
return errExpired
|
|
}
|
|
if !t.checkBond(fromID, from.IP) {
|
|
// No endpoint proof pong exists, we don't process the packet. This prevents an
|
|
// attack vector where the discovery protocol could be used to amplify traffic in a
|
|
// DDOS attack. A malicious actor would send a findnode request with the IP address
|
|
// and UDP port of the target as the source address. The recipient of the findnode
|
|
// packet would then send a neighbors packet (which is a much bigger packet than
|
|
// findnode) to the victim.
|
|
return errUnknownNode
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (t *UDPv4) handleFindnode(h *packetHandlerV4, from *net.UDPAddr, fromID enode.ID, mac []byte) {
|
|
req := h.Packet.(*v4wire.Findnode)
|
|
|
|
// Determine closest nodes.
|
|
target := enode.ID(crypto.Keccak256Hash(req.Target[:]))
|
|
closest := t.tab.findnodeByID(target, bucketSize, true).entries
|
|
|
|
// Send neighbors in chunks with at most maxNeighbors per packet
|
|
// to stay below the packet size limit.
|
|
p := v4wire.Neighbors{Expiration: uint64(time.Now().Add(expiration).Unix())}
|
|
var sent bool
|
|
for _, n := range closest {
|
|
if netutil.CheckRelayIP(from.IP, n.IP()) == nil {
|
|
p.Nodes = append(p.Nodes, nodeToRPC(n))
|
|
}
|
|
if len(p.Nodes) == v4wire.MaxNeighbors {
|
|
t.send(from, fromID, &p)
|
|
p.Nodes = p.Nodes[:0]
|
|
sent = true
|
|
}
|
|
}
|
|
if len(p.Nodes) > 0 || !sent {
|
|
t.send(from, fromID, &p)
|
|
}
|
|
}
|
|
|
|
// NEIGHBORS/v4
|
|
|
|
func (t *UDPv4) verifyNeighbors(h *packetHandlerV4, from *net.UDPAddr, fromID enode.ID, fromKey v4wire.Pubkey) error {
|
|
req := h.Packet.(*v4wire.Neighbors)
|
|
|
|
if v4wire.Expired(req.Expiration) {
|
|
return errExpired
|
|
}
|
|
if !t.handleReply(fromID, from.IP, h.Packet) {
|
|
return errUnsolicitedReply
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// ENRREQUEST/v4
|
|
|
|
func (t *UDPv4) verifyENRRequest(h *packetHandlerV4, from *net.UDPAddr, fromID enode.ID, fromKey v4wire.Pubkey) error {
|
|
req := h.Packet.(*v4wire.ENRRequest)
|
|
|
|
if v4wire.Expired(req.Expiration) {
|
|
return errExpired
|
|
}
|
|
if !t.checkBond(fromID, from.IP) {
|
|
return errUnknownNode
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (t *UDPv4) handleENRRequest(h *packetHandlerV4, from *net.UDPAddr, fromID enode.ID, mac []byte) {
|
|
t.send(from, fromID, &v4wire.ENRResponse{
|
|
ReplyTok: mac,
|
|
Record: *t.localNode.Node().Record(),
|
|
})
|
|
}
|
|
|
|
// ENRRESPONSE/v4
|
|
|
|
func (t *UDPv4) verifyENRResponse(h *packetHandlerV4, from *net.UDPAddr, fromID enode.ID, fromKey v4wire.Pubkey) error {
|
|
if !t.handleReply(fromID, from.IP, h.Packet) {
|
|
return errUnsolicitedReply
|
|
}
|
|
return nil
|
|
}
|