go-ethereum/p2p/enode/node_test.go
Lucas 804d45cc2e
p2p: DNS resolution for static nodes (#30822)
Closes #23210 

# Context 
When deploying Geth in Kubernetes with ReplicaSets, we encountered two
DNS-related issues affecting node connectivity. First, during startup,
Geth tries to resolve DNS names for static nodes too early in the config
unmarshaling phase. If peer nodes aren't ready yet (which is common in
Kubernetes rolling deployments), this causes an immediate failure:


```
INFO [11-26|10:03:42.816] Starting Geth on Ethereum mainnet...
INFO [11-26|10:03:42.817] Bumping default cache on mainnet         provided=1024 updated=4096
Fatal: config.toml, line 81: (p2p.Config.StaticNodes) lookup idontexist.geth.node: no such host
``` 

The second issue comes up when pods get rescheduled to different nodes -
their IPs change but peers keep using the initially resolved IP, never
updating the DNS mapping.

This PR adds proper DNS support for enode:// URLs by deferring resolution
to connection time. It also handles DNS failures gracefully instead of failing
fatally during startup, making it work better in container environments where
IPs are dynamic and peers come and go during rollouts.

---------

Co-authored-by: Felix Lange <fjl@twurst.com>
2024-12-13 12:46:12 +01:00

389 lines
11 KiB
Go

// 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 (
"bytes"
"encoding/hex"
"fmt"
"math/big"
"net/netip"
"testing"
"testing/quick"
"github.com/ethereum/go-ethereum/p2p/enr"
"github.com/ethereum/go-ethereum/rlp"
"github.com/stretchr/testify/assert"
)
var pyRecord, _ = hex.DecodeString("f884b8407098ad865b00a582051940cb9cf36836572411a47278783077011599ed5cd16b76f2635f4e234738f30813a89eb9137e3e3df5266e3a1f11df72ecf1145ccb9c01826964827634826970847f00000189736563703235366b31a103ca634cae0d49acb401d8a4c6b6fe8c55b70d115bf400769cc1400f3258cd31388375647082765f")
// TestPythonInterop checks that we can decode and verify a record produced by the Python
// implementation.
func TestPythonInterop(t *testing.T) {
var r enr.Record
if err := rlp.DecodeBytes(pyRecord, &r); err != nil {
t.Fatalf("can't decode: %v", err)
}
n, err := New(ValidSchemes, &r)
if err != nil {
t.Fatalf("can't verify record: %v", err)
}
var (
wantID = HexID("a448f24c6d18e575453db13171562b71999873db5b286df957af199ec94617f7")
wantSeq = uint64(1)
wantIP = enr.IPv4{127, 0, 0, 1}
wantUDP = enr.UDP(30303)
)
if n.Seq() != wantSeq {
t.Errorf("wrong seq: got %d, want %d", n.Seq(), wantSeq)
}
if n.ID() != wantID {
t.Errorf("wrong id: got %x, want %x", n.ID(), wantID)
}
want := map[enr.Entry]interface{}{new(enr.IPv4): &wantIP, new(enr.UDP): &wantUDP}
for k, v := range want {
desc := fmt.Sprintf("loading key %q", k.ENRKey())
if assert.NoError(t, n.Load(k), desc) {
assert.Equal(t, k, v, desc)
}
}
}
func TestNodeEndpoints(t *testing.T) {
id := HexID("00000000000000806ad9b61fa5ae014307ebdc964253adcd9f2c0a392aa11abc")
type endpointTest struct {
name string
node *Node
wantIP netip.Addr
wantUDP int
wantTCP int
wantQUIC int
wantDNS string
}
tests := []endpointTest{
{
name: "no-addr",
node: func() *Node {
var r enr.Record
return SignNull(&r, id)
}(),
},
{
name: "udp-only",
node: func() *Node {
var r enr.Record
r.Set(enr.UDP(9000))
return SignNull(&r, id)
}(),
wantUDP: 9000,
},
{
name: "tcp-only",
node: func() *Node {
var r enr.Record
r.Set(enr.TCP(9000))
return SignNull(&r, id)
}(),
wantTCP: 9000,
},
{
name: "quic-only",
node: func() *Node {
var r enr.Record
r.Set(enr.QUIC(9000))
return SignNull(&r, id)
}(),
},
{
name: "quic6-only",
node: func() *Node {
var r enr.Record
r.Set(enr.QUIC6(9000))
return SignNull(&r, id)
}(),
},
{
name: "ipv4-only-loopback",
node: func() *Node {
var r enr.Record
r.Set(enr.IPv4Addr(netip.MustParseAddr("127.0.0.1")))
return SignNull(&r, id)
}(),
wantIP: netip.MustParseAddr("127.0.0.1"),
},
{
name: "ipv4-only-unspecified",
node: func() *Node {
var r enr.Record
r.Set(enr.IPv4Addr(netip.MustParseAddr("0.0.0.0")))
return SignNull(&r, id)
}(),
wantIP: netip.MustParseAddr("0.0.0.0"),
},
{
name: "ipv4-only",
node: func() *Node {
var r enr.Record
r.Set(enr.IPv4Addr(netip.MustParseAddr("99.22.33.1")))
return SignNull(&r, id)
}(),
wantIP: netip.MustParseAddr("99.22.33.1"),
},
{
name: "ipv6-only",
node: func() *Node {
var r enr.Record
r.Set(enr.IPv6Addr(netip.MustParseAddr("2001::ff00:0042:8329")))
return SignNull(&r, id)
}(),
wantIP: netip.MustParseAddr("2001::ff00:0042:8329"),
},
{
name: "ipv4-loopback-and-ipv6-global",
node: func() *Node {
var r enr.Record
r.Set(enr.IPv4Addr(netip.MustParseAddr("127.0.0.1")))
r.Set(enr.UDP(30304))
r.Set(enr.IPv6Addr(netip.MustParseAddr("2001::ff00:0042:8329")))
r.Set(enr.UDP6(30306))
return SignNull(&r, id)
}(),
wantIP: netip.MustParseAddr("2001::ff00:0042:8329"),
wantUDP: 30306,
},
{
name: "ipv4-unspecified-and-ipv6-loopback",
node: func() *Node {
var r enr.Record
r.Set(enr.IPv4Addr(netip.MustParseAddr("0.0.0.0")))
r.Set(enr.IPv6Addr(netip.MustParseAddr("::1")))
return SignNull(&r, id)
}(),
wantIP: netip.MustParseAddr("::1"),
},
{
name: "ipv4-private-and-ipv6-global",
node: func() *Node {
var r enr.Record
r.Set(enr.IPv4Addr(netip.MustParseAddr("192.168.2.2")))
r.Set(enr.UDP(30304))
r.Set(enr.IPv6Addr(netip.MustParseAddr("2001::ff00:0042:8329")))
r.Set(enr.UDP6(30306))
return SignNull(&r, id)
}(),
wantIP: netip.MustParseAddr("2001::ff00:0042:8329"),
wantUDP: 30306,
},
{
name: "ipv4-local-and-ipv6-global",
node: func() *Node {
var r enr.Record
r.Set(enr.IPv4Addr(netip.MustParseAddr("169.254.2.6")))
r.Set(enr.UDP(30304))
r.Set(enr.IPv6Addr(netip.MustParseAddr("2001::ff00:0042:8329")))
r.Set(enr.UDP6(30306))
return SignNull(&r, id)
}(),
wantIP: netip.MustParseAddr("2001::ff00:0042:8329"),
wantUDP: 30306,
},
{
name: "ipv4-private-and-ipv6-private",
node: func() *Node {
var r enr.Record
r.Set(enr.IPv4Addr(netip.MustParseAddr("192.168.2.2")))
r.Set(enr.UDP(30304))
r.Set(enr.IPv6Addr(netip.MustParseAddr("fd00::abcd:1")))
r.Set(enr.UDP6(30306))
return SignNull(&r, id)
}(),
wantIP: netip.MustParseAddr("192.168.2.2"),
wantUDP: 30304,
},
{
name: "ipv4-private-and-ipv6-link-local",
node: func() *Node {
var r enr.Record
r.Set(enr.IPv4Addr(netip.MustParseAddr("192.168.2.2")))
r.Set(enr.UDP(30304))
r.Set(enr.IPv6Addr(netip.MustParseAddr("fe80::1")))
r.Set(enr.UDP6(30306))
return SignNull(&r, id)
}(),
wantIP: netip.MustParseAddr("192.168.2.2"),
wantUDP: 30304,
},
{
name: "ipv4-quic",
node: func() *Node {
var r enr.Record
r.Set(enr.IPv4Addr(netip.MustParseAddr("99.22.33.1")))
r.Set(enr.QUIC(9001))
return SignNull(&r, id)
}(),
wantIP: netip.MustParseAddr("99.22.33.1"),
wantQUIC: 9001,
},
{ // Because the node is IPv4, the quic6 entry won't be loaded.
name: "ipv4-quic6",
node: func() *Node {
var r enr.Record
r.Set(enr.IPv4Addr(netip.MustParseAddr("99.22.33.1")))
r.Set(enr.QUIC6(9001))
return SignNull(&r, id)
}(),
wantIP: netip.MustParseAddr("99.22.33.1"),
},
{
name: "ipv6-quic",
node: func() *Node {
var r enr.Record
r.Set(enr.IPv6Addr(netip.MustParseAddr("2001::ff00:0042:8329")))
r.Set(enr.QUIC(9001))
return SignNull(&r, id)
}(),
wantIP: netip.MustParseAddr("2001::ff00:0042:8329"),
},
{
name: "ipv6-quic6",
node: func() *Node {
var r enr.Record
r.Set(enr.IPv6Addr(netip.MustParseAddr("2001::ff00:0042:8329")))
r.Set(enr.QUIC6(9001))
return SignNull(&r, id)
}(),
wantIP: netip.MustParseAddr("2001::ff00:0042:8329"),
wantQUIC: 9001,
},
{
name: "dns-only",
node: func() *Node {
var r enr.Record
r.Set(enr.UDP(30303))
r.Set(enr.TCP(30303))
n := SignNull(&r, id).WithHostname("example.com")
return n
}(),
wantTCP: 30303,
wantUDP: 30303,
wantDNS: "example.com",
},
}
for _, test := range tests {
t.Run(test.name, func(t *testing.T) {
if test.wantIP != test.node.IPAddr() {
t.Errorf("node has wrong IP %v, want %v", test.node.IPAddr(), test.wantIP)
}
if test.wantUDP != test.node.UDP() {
t.Errorf("node has wrong UDP port %d, want %d", test.node.UDP(), test.wantUDP)
}
if test.wantTCP != test.node.TCP() {
t.Errorf("node has wrong TCP port %d, want %d", test.node.TCP(), test.wantTCP)
}
if quic, _ := test.node.QUICEndpoint(); test.wantQUIC != int(quic.Port()) {
t.Errorf("node has wrong QUIC port %d, want %d", quic.Port(), test.wantQUIC)
}
if test.wantDNS != test.node.Hostname() {
t.Errorf("node has wrong DNS name %s, want %s", test.node.Hostname(), test.wantDNS)
}
})
}
}
func TestHexID(t *testing.T) {
ref := ID{0, 0, 0, 0, 0, 0, 0, 128, 106, 217, 182, 31, 165, 174, 1, 67, 7, 235, 220, 150, 66, 83, 173, 205, 159, 44, 10, 57, 42, 161, 26, 188}
id1 := HexID("0x00000000000000806ad9b61fa5ae014307ebdc964253adcd9f2c0a392aa11abc")
id2 := HexID("00000000000000806ad9b61fa5ae014307ebdc964253adcd9f2c0a392aa11abc")
if id1 != ref {
t.Errorf("wrong id1\ngot %v\nwant %v", id1[:], ref[:])
}
if id2 != ref {
t.Errorf("wrong id2\ngot %v\nwant %v", id2[:], ref[:])
}
}
func TestID_textEncoding(t *testing.T) {
ref := ID{
0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x10,
0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x20,
0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x30,
0x31, 0x32,
}
hex := "0102030405060708091011121314151617181920212223242526272829303132"
text, err := ref.MarshalText()
if err != nil {
t.Fatal(err)
}
if !bytes.Equal(text, []byte(hex)) {
t.Fatalf("text encoding did not match\nexpected: %s\ngot: %s", hex, text)
}
id := new(ID)
if err := id.UnmarshalText(text); err != nil {
t.Fatal(err)
}
if *id != ref {
t.Fatalf("text decoding did not match\nexpected: %s\ngot: %s", ref, id)
}
}
func TestID_distcmp(t *testing.T) {
distcmpBig := func(target, a, b ID) int {
tbig := new(big.Int).SetBytes(target[:])
abig := new(big.Int).SetBytes(a[:])
bbig := new(big.Int).SetBytes(b[:])
return new(big.Int).Xor(tbig, abig).Cmp(new(big.Int).Xor(tbig, bbig))
}
if err := quick.CheckEqual(DistCmp, distcmpBig, nil); err != nil {
t.Error(err)
}
}
// The random tests is likely to miss the case where a and b are equal,
// this test checks it explicitly.
func TestID_distcmpEqual(t *testing.T) {
base := ID{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}
x := ID{15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0}
if DistCmp(base, x, x) != 0 {
t.Errorf("DistCmp(base, x, x) != 0")
}
}
func TestID_logdist(t *testing.T) {
logdistBig := func(a, b ID) int {
abig, bbig := new(big.Int).SetBytes(a[:]), new(big.Int).SetBytes(b[:])
return new(big.Int).Xor(abig, bbig).BitLen()
}
if err := quick.CheckEqual(LogDist, logdistBig, nil); err != nil {
t.Error(err)
}
}
// The random tests is likely to miss the case where a and b are equal,
// this test checks it explicitly.
func TestID_logdistEqual(t *testing.T) {
x := ID{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}
if LogDist(x, x) != 0 {
t.Errorf("LogDist(x, x) != 0")
}
}