erigon-pulse/p2p/dnsdisc/tree.go

385 lines
9.7 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 dnsdisc
import (
"bytes"
"crypto/ecdsa"
"encoding/base32"
"encoding/base64"
"fmt"
"io"
"sort"
"strings"
"github.com/ledgerwatch/turbo-geth/crypto"
"github.com/ledgerwatch/turbo-geth/p2p/enode"
"github.com/ledgerwatch/turbo-geth/p2p/enr"
"github.com/ledgerwatch/turbo-geth/rlp"
"golang.org/x/crypto/sha3"
)
// Tree is a merkle tree of node records.
type Tree struct {
root *rootEntry
entries map[string]entry
}
// Sign signs the tree with the given private key and sets the sequence number.
func (t *Tree) Sign(key *ecdsa.PrivateKey, domain string) (url string, err error) {
root := *t.root
sig, err := crypto.Sign(root.sigHash(), key)
if err != nil {
return "", err
}
root.sig = sig
t.root = &root
link := &linkEntry{domain, &key.PublicKey}
return link.url(), nil
}
// SetSignature verifies the given signature and assigns it as the tree's current
// signature if valid.
func (t *Tree) SetSignature(pubkey *ecdsa.PublicKey, signature string) error {
sig, err := b64format.DecodeString(signature)
if err != nil || len(sig) != crypto.SignatureLength {
return errInvalidSig
}
root := *t.root
root.sig = sig
if !root.verifySignature(pubkey) {
return errInvalidSig
}
t.root = &root
return nil
}
// Seq returns the sequence number of the tree.
func (t *Tree) Seq() uint {
return t.root.seq
}
// Signature returns the signature of the tree.
func (t *Tree) Signature() string {
return b64format.EncodeToString(t.root.sig)
}
// ToTXT returns all DNS TXT records required for the tree.
func (t *Tree) ToTXT(domain string) map[string]string {
records := map[string]string{domain: t.root.String()}
for _, e := range t.entries {
sd := subdomain(e)
if domain != "" {
sd = sd + "." + domain
}
records[sd] = e.String()
}
return records
}
// Links returns all links contained in the tree.
func (t *Tree) Links() []string {
var links []string
for _, e := range t.entries {
if le, ok := e.(*linkEntry); ok {
links = append(links, le.url())
}
}
return links
}
// Nodes returns all nodes contained in the tree.
func (t *Tree) Nodes() []*enode.Node {
var nodes []*enode.Node
for _, e := range t.entries {
if ee, ok := e.(*enrEntry); ok {
nodes = append(nodes, ee.node)
}
}
return nodes
}
const (
hashAbbrev = 16
maxChildren = 300 / (hashAbbrev * (13 / 8))
minHashLength = 12
rootPrefix = "enrtree-root=v1"
)
// MakeTree creates a tree containing the given nodes and links.
func MakeTree(seq uint, nodes []*enode.Node, links []string) (*Tree, error) {
// Sort records by ID and ensure all nodes have a valid record.
records := make([]*enode.Node, len(nodes))
copy(records, nodes)
sortByID(records)
for _, n := range records {
if len(n.Record().Signature()) == 0 {
return nil, fmt.Errorf("can't add node %v: unsigned node record", n.ID())
}
}
// Create the leaf list.
enrEntries := make([]entry, len(records))
for i, r := range records {
enrEntries[i] = &enrEntry{r}
}
linkEntries := make([]entry, len(links))
for i, l := range links {
le, err := parseURL(l)
if err != nil {
return nil, err
}
linkEntries[i] = le
}
// Create intermediate nodes.
t := &Tree{entries: make(map[string]entry)}
eroot := t.build(enrEntries)
t.entries[subdomain(eroot)] = eroot
lroot := t.build(linkEntries)
t.entries[subdomain(lroot)] = lroot
t.root = &rootEntry{seq: seq, eroot: subdomain(eroot), lroot: subdomain(lroot)}
return t, nil
}
func (t *Tree) build(entries []entry) entry {
if len(entries) == 1 {
return entries[0]
}
if len(entries) <= maxChildren {
hashes := make([]string, len(entries))
for i, e := range entries {
hashes[i] = subdomain(e)
t.entries[hashes[i]] = e
}
return &subtreeEntry{hashes}
}
var subtrees []entry
for len(entries) > 0 {
n := maxChildren
if len(entries) < n {
n = len(entries)
}
sub := t.build(entries[:n])
entries = entries[n:]
subtrees = append(subtrees, sub)
t.entries[subdomain(sub)] = sub
}
return t.build(subtrees)
}
func sortByID(nodes []*enode.Node) []*enode.Node {
sort.Slice(nodes, func(i, j int) bool {
return bytes.Compare(nodes[i].ID().Bytes(), nodes[j].ID().Bytes()) < 0
})
return nodes
}
// Entry Types
type entry interface {
fmt.Stringer
}
type (
rootEntry struct {
eroot string
lroot string
seq uint
sig []byte
}
subtreeEntry struct {
children []string
}
enrEntry struct {
node *enode.Node
}
linkEntry struct {
domain string
pubkey *ecdsa.PublicKey
}
)
// Entry Encoding
var (
b32format = base32.StdEncoding.WithPadding(base32.NoPadding)
b64format = base64.URLEncoding
)
func subdomain(e entry) string {
h := sha3.NewLegacyKeccak256()
io.WriteString(h, e.String())
return b32format.EncodeToString(h.Sum(nil)[:16])
}
func (e *rootEntry) String() string {
return fmt.Sprintf(rootPrefix+" e=%s l=%s seq=%d sig=%s", e.eroot, e.lroot, e.seq, b64format.EncodeToString(e.sig))
}
func (e *rootEntry) sigHash() []byte {
h := sha3.NewLegacyKeccak256()
fmt.Fprintf(h, rootPrefix+" e=%s l=%s seq=%d", e.eroot, e.lroot, e.seq)
return h.Sum(nil)
}
func (e *rootEntry) verifySignature(pubkey *ecdsa.PublicKey) bool {
sig := e.sig[:crypto.RecoveryIDOffset] // remove recovery id
return crypto.VerifySignature(crypto.FromECDSAPub(pubkey), e.sigHash(), sig)
}
func (e *subtreeEntry) String() string {
return "enrtree=" + strings.Join(e.children, ",")
}
func (e *enrEntry) String() string {
enc, _ := rlp.EncodeToBytes(e.node.Record())
return "enr=" + b64format.EncodeToString(enc)
}
func (e *linkEntry) String() string {
return "enrtree-link=" + e.link()
}
func (e *linkEntry) url() string {
return "enrtree://" + e.link()
}
func (e *linkEntry) link() string {
return fmt.Sprintf("%s@%s", b32format.EncodeToString(crypto.CompressPubkey(e.pubkey)), e.domain)
}
// Entry Parsing
func parseEntry(e string, validSchemes enr.IdentityScheme) (entry, error) {
switch {
case strings.HasPrefix(e, "enrtree-link="):
return parseLink(e[13:])
case strings.HasPrefix(e, "enrtree="):
return parseSubtree(e[8:])
case strings.HasPrefix(e, "enr="):
return parseENR(e[4:], validSchemes)
default:
return nil, errUnknownEntry
}
}
func parseRoot(e string) (rootEntry, error) {
var eroot, lroot, sig string
var seq uint
if _, err := fmt.Sscanf(e, rootPrefix+" e=%s l=%s seq=%d sig=%s", &eroot, &lroot, &seq, &sig); err != nil {
return rootEntry{}, entryError{"root", errSyntax}
}
if !isValidHash(eroot) || !isValidHash(lroot) {
return rootEntry{}, entryError{"root", errInvalidChild}
}
sigb, err := b64format.DecodeString(sig)
if err != nil || len(sigb) != crypto.SignatureLength {
return rootEntry{}, entryError{"root", errInvalidSig}
}
return rootEntry{eroot, lroot, seq, sigb}, nil
}
func parseLink(e string) (entry, error) {
pos := strings.IndexByte(e, '@')
if pos == -1 {
return nil, entryError{"link", errNoPubkey}
}
keystring, domain := e[:pos], e[pos+1:]
keybytes, err := b32format.DecodeString(keystring)
if err != nil {
return nil, entryError{"link", errBadPubkey}
}
key, err := crypto.DecompressPubkey(keybytes)
if err != nil {
return nil, entryError{"link", errBadPubkey}
}
return &linkEntry{domain, key}, nil
}
func parseSubtree(e string) (entry, error) {
if e == "" {
return &subtreeEntry{}, nil // empty entry is OK
}
hashes := make([]string, 0, strings.Count(e, ","))
for _, c := range strings.Split(e, ",") {
if !isValidHash(c) {
return nil, entryError{"subtree", errInvalidChild}
}
hashes = append(hashes, c)
}
return &subtreeEntry{hashes}, nil
}
func parseENR(e string, validSchemes enr.IdentityScheme) (entry, error) {
enc, err := b64format.DecodeString(e)
if err != nil {
return nil, entryError{"enr", errInvalidENR}
}
var rec enr.Record
if err := rlp.DecodeBytes(enc, &rec); err != nil {
return nil, entryError{"enr", err}
}
n, err := enode.New(validSchemes, &rec)
if err != nil {
return nil, entryError{"enr", err}
}
return &enrEntry{n}, nil
}
func isValidHash(s string) bool {
dlen := b32format.DecodedLen(len(s))
if dlen < minHashLength || dlen > 32 || strings.ContainsAny(s, "\n\r") {
return false
}
buf := make([]byte, 32)
_, err := b32format.Decode(buf, []byte(s))
return err == nil
}
// truncateHash truncates the given base32 hash string to the minimum acceptable length.
func truncateHash(hash string) string {
maxLen := b32format.EncodedLen(minHashLength)
if len(hash) < maxLen {
panic(fmt.Errorf("dnsdisc: hash %q is too short", hash))
}
return hash[:maxLen]
}
// URL encoding
// ParseURL parses an enrtree:// URL and returns its components.
func ParseURL(url string) (domain string, pubkey *ecdsa.PublicKey, err error) {
le, err := parseURL(url)
if err != nil {
return "", nil, err
}
return le.domain, le.pubkey, nil
}
func parseURL(url string) (*linkEntry, error) {
const scheme = "enrtree://"
if !strings.HasPrefix(url, scheme) {
return nil, fmt.Errorf("wrong/missing scheme 'enrtree' in URL")
}
le, err := parseLink(url[len(scheme):])
if err != nil {
return nil, err.(entryError).err
}
return le.(*linkEntry), nil
}