// Copyright 2016 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 light implements on-demand retrieval capable state and chain objects
// for the Ethereum Light Client.
package les
import (
"encoding/binary"
"errors"
"fmt"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/rawdb"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/light"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/trie"
)
var (
errInvalidMessageType = errors.New("invalid message type")
errInvalidEntryCount = errors.New("invalid number of response entries")
errHeaderUnavailable = errors.New("header unavailable")
errTxHashMismatch = errors.New("transaction hash mismatch")
errUncleHashMismatch = errors.New("uncle hash mismatch")
errReceiptHashMismatch = errors.New("receipt hash mismatch")
errDataHashMismatch = errors.New("data hash mismatch")
errCHTHashMismatch = errors.New("cht hash mismatch")
errCHTNumberMismatch = errors.New("cht number mismatch")
errUselessNodes = errors.New("useless nodes in merkle proof nodeset")
)
type LesOdrRequest interface {
GetCost(*peer) uint64
CanSend(*peer) bool
Request(uint64, *peer) error
Validate(ethdb.Database, *Msg) error
}
func LesRequest(req light.OdrRequest) LesOdrRequest {
switch r := req.(type) {
case *light.BlockRequest:
return (*BlockRequest)(r)
case *light.ReceiptsRequest:
return (*ReceiptsRequest)(r)
case *light.TrieRequest:
return (*TrieRequest)(r)
case *light.CodeRequest:
return (*CodeRequest)(r)
case *light.ChtRequest:
return (*ChtRequest)(r)
case *light.BloomRequest:
return (*BloomRequest)(r)
default:
return nil
}
}
// BlockRequest is the ODR request type for block bodies
type BlockRequest light.BlockRequest
// GetCost returns the cost of the given ODR request according to the serving
// peer's cost table (implementation of LesOdrRequest)
func (r *BlockRequest) GetCost(peer *peer) uint64 {
return peer.GetRequestCost(GetBlockBodiesMsg, 1)
}
// CanSend tells if a certain peer is suitable for serving the given request
func (r *BlockRequest) CanSend(peer *peer) bool {
return peer.HasBlock(r.Hash, r.Number)
}
// Request sends an ODR request to the LES network (implementation of LesOdrRequest)
func (r *BlockRequest) Request(reqID uint64, peer *peer) error {
peer.Log().Debug("Requesting block body", "hash", r.Hash)
return peer.RequestBodies(reqID, r.GetCost(peer), []common.Hash{r.Hash})
}
// Valid processes an ODR request reply message from the LES network
// returns true and stores results in memory if the message was a valid reply
// to the request (implementation of LesOdrRequest)
func (r *BlockRequest) Validate(db ethdb.Database, msg *Msg) error {
log.Debug("Validating block body", "hash", r.Hash)
// Ensure we have a correct message with a single block body
if msg.MsgType != MsgBlockBodies {
return errInvalidMessageType
}
bodies := msg.Obj.([]*types.Body)
if len(bodies) != 1 {
return errInvalidEntryCount
}
body := bodies[0]
// Retrieve our stored header and validate block content against it
header := rawdb.ReadHeader(db, r.Hash, r.Number)
if header == nil {
return errHeaderUnavailable
}
if header.TxHash != types.DeriveSha(types.Transactions(body.Transactions)) {
return errTxHashMismatch
}
if header.UncleHash != types.CalcUncleHash(body.Uncles) {
return errUncleHashMismatch
}
// Validations passed, encode and store RLP
data, err := rlp.EncodeToBytes(body)
if err != nil {
return err
}
r.Rlp = data
return nil
}
// ReceiptsRequest is the ODR request type for block receipts by block hash
type ReceiptsRequest light.ReceiptsRequest
// GetCost returns the cost of the given ODR request according to the serving
// peer's cost table (implementation of LesOdrRequest)
func (r *ReceiptsRequest) GetCost(peer *peer) uint64 {
return peer.GetRequestCost(GetReceiptsMsg, 1)
}
// CanSend tells if a certain peer is suitable for serving the given request
func (r *ReceiptsRequest) CanSend(peer *peer) bool {
return peer.HasBlock(r.Hash, r.Number)
}
// Request sends an ODR request to the LES network (implementation of LesOdrRequest)
func (r *ReceiptsRequest) Request(reqID uint64, peer *peer) error {
peer.Log().Debug("Requesting block receipts", "hash", r.Hash)
return peer.RequestReceipts(reqID, r.GetCost(peer), []common.Hash{r.Hash})
}
// Valid processes an ODR request reply message from the LES network
// returns true and stores results in memory if the message was a valid reply
// to the request (implementation of LesOdrRequest)
func (r *ReceiptsRequest) Validate(db ethdb.Database, msg *Msg) error {
log.Debug("Validating block receipts", "hash", r.Hash)
// Ensure we have a correct message with a single block receipt
if msg.MsgType != MsgReceipts {
return errInvalidMessageType
}
receipts := msg.Obj.([]types.Receipts)
if len(receipts) != 1 {
return errInvalidEntryCount
}
receipt := receipts[0]
// Retrieve our stored header and validate receipt content against it
header := rawdb.ReadHeader(db, r.Hash, r.Number)
if header == nil {
return errHeaderUnavailable
}
if header.ReceiptHash != types.DeriveSha(receipt) {
return errReceiptHashMismatch
}
// Validations passed, store and return
r.Receipts = receipt
return nil
}
type ProofReq struct {
BHash common.Hash
AccKey, Key []byte
FromLevel uint
}
// ODR request type for state/storage trie entries, see LesOdrRequest interface
type TrieRequest light.TrieRequest
// GetCost returns the cost of the given ODR request according to the serving
// peer's cost table (implementation of LesOdrRequest)
func (r *TrieRequest) GetCost(peer *peer) uint64 {
switch peer.version {
case lpv1:
return peer.GetRequestCost(GetProofsV1Msg, 1)
case lpv2:
return peer.GetRequestCost(GetProofsV2Msg, 1)
default:
panic(nil)
}
}
// CanSend tells if a certain peer is suitable for serving the given request
func (r *TrieRequest) CanSend(peer *peer) bool {
return peer.HasBlock(r.Id.BlockHash, r.Id.BlockNumber)
}
// Request sends an ODR request to the LES network (implementation of LesOdrRequest)
func (r *TrieRequest) Request(reqID uint64, peer *peer) error {
peer.Log().Debug("Requesting trie proof", "root", r.Id.Root, "key", r.Key)
req := ProofReq{
BHash: r.Id.BlockHash,
AccKey: r.Id.AccKey,
Key: r.Key,
}
return peer.RequestProofs(reqID, r.GetCost(peer), []ProofReq{req})
}
// Valid processes an ODR request reply message from the LES network
// returns true and stores results in memory if the message was a valid reply
// to the request (implementation of LesOdrRequest)
func (r *TrieRequest) Validate(db ethdb.Database, msg *Msg) error {
log.Debug("Validating trie proof", "root", r.Id.Root, "key", r.Key)
switch msg.MsgType {
case MsgProofsV1:
proofs := msg.Obj.([]light.NodeList)
if len(proofs) != 1 {
return errInvalidEntryCount
}
nodeSet := proofs[0].NodeSet()
// Verify the proof and store if checks out
if _, _, err := trie.VerifyProof(r.Id.Root, r.Key, nodeSet); err != nil {
return fmt.Errorf("merkle proof verification failed: %v", err)
}
r.Proof = nodeSet
return nil
case MsgProofsV2:
proofs := msg.Obj.(light.NodeList)
// Verify the proof and store if checks out
nodeSet := proofs.NodeSet()
reads := &readTraceDB{db: nodeSet}
if _, _, err := trie.VerifyProof(r.Id.Root, r.Key, reads); err != nil {
return fmt.Errorf("merkle proof verification failed: %v", err)
}
// check if all nodes have been read by VerifyProof
if len(reads.reads) != nodeSet.KeyCount() {
return errUselessNodes
}
r.Proof = nodeSet
return nil
default:
return errInvalidMessageType
}
}
type CodeReq struct {
BHash common.Hash
AccKey []byte
}
// ODR request type for node data (used for retrieving contract code), see LesOdrRequest interface
type CodeRequest light.CodeRequest
// GetCost returns the cost of the given ODR request according to the serving
// peer's cost table (implementation of LesOdrRequest)
func (r *CodeRequest) GetCost(peer *peer) uint64 {
return peer.GetRequestCost(GetCodeMsg, 1)
}
// CanSend tells if a certain peer is suitable for serving the given request
func (r *CodeRequest) CanSend(peer *peer) bool {
return peer.HasBlock(r.Id.BlockHash, r.Id.BlockNumber)
}
// Request sends an ODR request to the LES network (implementation of LesOdrRequest)
func (r *CodeRequest) Request(reqID uint64, peer *peer) error {
peer.Log().Debug("Requesting code data", "hash", r.Hash)
req := CodeReq{
BHash: r.Id.BlockHash,
AccKey: r.Id.AccKey,
}
return peer.RequestCode(reqID, r.GetCost(peer), []CodeReq{req})
}
// Valid processes an ODR request reply message from the LES network
// returns true and stores results in memory if the message was a valid reply
// to the request (implementation of LesOdrRequest)
func (r *CodeRequest) Validate(db ethdb.Database, msg *Msg) error {
log.Debug("Validating code data", "hash", r.Hash)
// Ensure we have a correct message with a single code element
if msg.MsgType != MsgCode {
return errInvalidMessageType
}
reply := msg.Obj.([][]byte)
if len(reply) != 1 {
return errInvalidEntryCount
}
data := reply[0]
// Verify the data and store if checks out
if hash := crypto.Keccak256Hash(data); r.Hash != hash {
return errDataHashMismatch
}
r.Data = data
return nil
}
const (
// helper trie type constants
htCanonical = iota // Canonical hash trie
htBloomBits // BloomBits trie
// applicable for all helper trie requests
auxRoot = 1
// applicable for htCanonical
auxHeader = 2
)
type HelperTrieReq struct {
Type uint
TrieIdx uint64
Key []byte
FromLevel, AuxReq uint
}
type HelperTrieResps struct { // describes all responses, not just a single one
Proofs light.NodeList
AuxData [][]byte
}
// legacy LES/1
type ChtReq struct {
ChtNum, BlockNum uint64
FromLevel uint
}
// legacy LES/1
type ChtResp struct {
Header *types.Header
Proof []rlp.RawValue
}
// ODR request type for requesting headers by Canonical Hash Trie, see LesOdrRequest interface
type ChtRequest light.ChtRequest
// GetCost returns the cost of the given ODR request according to the serving
// peer's cost table (implementation of LesOdrRequest)
func (r *ChtRequest) GetCost(peer *peer) uint64 {
switch peer.version {
case lpv1:
return peer.GetRequestCost(GetHeaderProofsMsg, 1)
case lpv2:
return peer.GetRequestCost(GetHelperTrieProofsMsg, 1)
default:
panic(nil)
}
}
// CanSend tells if a certain peer is suitable for serving the given request
func (r *ChtRequest) CanSend(peer *peer) bool {
peer.lock.RLock()
defer peer.lock.RUnlock()
return peer.headInfo.Number >= light.HelperTrieConfirmations && r.ChtNum <= (peer.headInfo.Number-light.HelperTrieConfirmations)/light.CHTFrequencyClient
}
// Request sends an ODR request to the LES network (implementation of LesOdrRequest)
func (r *ChtRequest) Request(reqID uint64, peer *peer) error {
peer.Log().Debug("Requesting CHT", "cht", r.ChtNum, "block", r.BlockNum)
var encNum [8]byte
binary.BigEndian.PutUint64(encNum[:], r.BlockNum)
req := HelperTrieReq{
Type: htCanonical,
TrieIdx: r.ChtNum,
Key: encNum[:],
AuxReq: auxHeader,
}
return peer.RequestHelperTrieProofs(reqID, r.GetCost(peer), []HelperTrieReq{req})
}
// Valid processes an ODR request reply message from the LES network
// returns true and stores results in memory if the message was a valid reply
// to the request (implementation of LesOdrRequest)
func (r *ChtRequest) Validate(db ethdb.Database, msg *Msg) error {
log.Debug("Validating CHT", "cht", r.ChtNum, "block", r.BlockNum)
switch msg.MsgType {
case MsgHeaderProofs: // LES/1 backwards compatibility
proofs := msg.Obj.([]ChtResp)
if len(proofs) != 1 {
return errInvalidEntryCount
}
proof := proofs[0]
// Verify the CHT
var encNumber [8]byte
binary.BigEndian.PutUint64(encNumber[:], r.BlockNum)
value, _, err := trie.VerifyProof(r.ChtRoot, encNumber[:], light.NodeList(proof.Proof).NodeSet())
if err != nil {
return err
}
var node light.ChtNode
if err := rlp.DecodeBytes(value, &node); err != nil {
return err
}
if node.Hash != proof.Header.Hash() {
return errCHTHashMismatch
}
// Verifications passed, store and return
r.Header = proof.Header
r.Proof = light.NodeList(proof.Proof).NodeSet()
r.Td = node.Td
case MsgHelperTrieProofs:
resp := msg.Obj.(HelperTrieResps)
if len(resp.AuxData) != 1 {
return errInvalidEntryCount
}
nodeSet := resp.Proofs.NodeSet()
headerEnc := resp.AuxData[0]
if len(headerEnc) == 0 {
return errHeaderUnavailable
}
header := new(types.Header)
if err := rlp.DecodeBytes(headerEnc, header); err != nil {
return errHeaderUnavailable
}
// Verify the CHT
var encNumber [8]byte
binary.BigEndian.PutUint64(encNumber[:], r.BlockNum)
reads := &readTraceDB{db: nodeSet}
value, _, err := trie.VerifyProof(r.ChtRoot, encNumber[:], reads)
if err != nil {
return fmt.Errorf("merkle proof verification failed: %v", err)
}
if len(reads.reads) != nodeSet.KeyCount() {
return errUselessNodes
}
var node light.ChtNode
if err := rlp.DecodeBytes(value, &node); err != nil {
return err
}
if node.Hash != header.Hash() {
return errCHTHashMismatch
}
if r.BlockNum != header.Number.Uint64() {
return errCHTNumberMismatch
}
// Verifications passed, store and return
r.Header = header
r.Proof = nodeSet
r.Td = node.Td
default:
return errInvalidMessageType
}
return nil
}
type BloomReq struct {
BloomTrieNum, BitIdx, SectionIdx, FromLevel uint64
}
// ODR request type for requesting headers by Canonical Hash Trie, see LesOdrRequest interface
type BloomRequest light.BloomRequest
// GetCost returns the cost of the given ODR request according to the serving
// peer's cost table (implementation of LesOdrRequest)
func (r *BloomRequest) GetCost(peer *peer) uint64 {
return peer.GetRequestCost(GetHelperTrieProofsMsg, len(r.SectionIdxList))
}
// CanSend tells if a certain peer is suitable for serving the given request
func (r *BloomRequest) CanSend(peer *peer) bool {
peer.lock.RLock()
defer peer.lock.RUnlock()
if peer.version < lpv2 {
return false
}
return peer.headInfo.Number >= light.HelperTrieConfirmations && r.BloomTrieNum <= (peer.headInfo.Number-light.HelperTrieConfirmations)/light.BloomTrieFrequency
}
// Request sends an ODR request to the LES network (implementation of LesOdrRequest)
func (r *BloomRequest) Request(reqID uint64, peer *peer) error {
peer.Log().Debug("Requesting BloomBits", "bloomTrie", r.BloomTrieNum, "bitIdx", r.BitIdx, "sections", r.SectionIdxList)
reqs := make([]HelperTrieReq, len(r.SectionIdxList))
var encNumber [10]byte
binary.BigEndian.PutUint16(encNumber[:2], uint16(r.BitIdx))
for i, sectionIdx := range r.SectionIdxList {
binary.BigEndian.PutUint64(encNumber[2:], sectionIdx)
reqs[i] = HelperTrieReq{
Type: htBloomBits,
TrieIdx: r.BloomTrieNum,
Key: common.CopyBytes(encNumber[:]),
}
}
return peer.RequestHelperTrieProofs(reqID, r.GetCost(peer), reqs)
}
// Valid processes an ODR request reply message from the LES network
// returns true and stores results in memory if the message was a valid reply
// to the request (implementation of LesOdrRequest)
func (r *BloomRequest) Validate(db ethdb.Database, msg *Msg) error {
log.Debug("Validating BloomBits", "bloomTrie", r.BloomTrieNum, "bitIdx", r.BitIdx, "sections", r.SectionIdxList)
// Ensure we have a correct message with a single proof element
if msg.MsgType != MsgHelperTrieProofs {
return errInvalidMessageType
}
resps := msg.Obj.(HelperTrieResps)
proofs := resps.Proofs
nodeSet := proofs.NodeSet()
reads := &readTraceDB{db: nodeSet}
r.BloomBits = make([][]byte, len(r.SectionIdxList))
// Verify the proofs
var encNumber [10]byte
binary.BigEndian.PutUint16(encNumber[:2], uint16(r.BitIdx))
for i, idx := range r.SectionIdxList {
binary.BigEndian.PutUint64(encNumber[2:], idx)
value, _, err := trie.VerifyProof(r.BloomTrieRoot, encNumber[:], reads)
if err != nil {
return err
}
r.BloomBits[i] = value
}
if len(reads.reads) != nodeSet.KeyCount() {
return errUselessNodes
}
r.Proofs = nodeSet
return nil
}
// readTraceDB stores the keys of database reads. We use this to check that received node
// sets contain only the trie nodes necessary to make proofs pass.
type readTraceDB struct {
db trie.DatabaseReader
reads map[string]struct{}
}
// Get returns a stored node
func (db *readTraceDB) Get(k []byte) ([]byte, error) {
if db.reads == nil {
db.reads = make(map[string]struct{})
}
db.reads[string(k)] = struct{}{}
return db.db.Get(k)
}
// Has returns true if the node set contains the given key
func (db *readTraceDB) Has(key []byte) (bool, error) {
_, err := db.Get(key)
return err == nil, nil
}
