les: light client protocol and API

1 files changed, 325 insertions, 0 deletions

diff --git a/les/odr_requests.go b/les/odr_requests.go
new file mode 100644
index 000000000..bf0346977
--- /dev/null
+++ b/les/odr_requests.go
@@ -0,0 +1,325 @@
+// Copyright 2015 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 (
+	"bytes"
+	"encoding/binary"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core"
+	"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/logger"
+	"github.com/ethereum/go-ethereum/logger/glog"
+	"github.com/ethereum/go-ethereum/rlp"
+	"github.com/ethereum/go-ethereum/trie"
+)
+
+type LesOdrRequest interface {
+	GetCost(*peer) uint64
+	Request(uint64, *peer) error
+	Valid(ethdb.Database, *Msg) bool // if true, keeps the retrieved object
+}
+
+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)
+	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 (self *BlockRequest) GetCost(peer *peer) uint64 {
+	return peer.GetRequestCost(GetBlockBodiesMsg, 1)
+}
+
+// Request sends an ODR request to the LES network (implementation of LesOdrRequest)
+func (self *BlockRequest) Request(reqID uint64, peer *peer) error {
+	glog.V(logger.Debug).Infof("ODR: requesting body of block %08x from peer %v", self.Hash[:4], peer.id)
+	return peer.RequestBodies(reqID, self.GetCost(peer), []common.Hash{self.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 (self *BlockRequest) Valid(db ethdb.Database, msg *Msg) bool {
+	glog.V(logger.Debug).Infof("ODR: validating body of block %08x", self.Hash[:4])
+	if msg.MsgType != MsgBlockBodies {
+		glog.V(logger.Debug).Infof("ODR: invalid message type")
+		return false
+	}
+	bodies := msg.Obj.([]*types.Body)
+	if len(bodies) != 1 {
+		glog.V(logger.Debug).Infof("ODR: invalid number of entries: %d", len(bodies))
+		return false
+	}
+	body := bodies[0]
+	header := core.GetHeader(db, self.Hash, self.Number)
+	if header == nil {
+		glog.V(logger.Debug).Infof("ODR: header not found for block %08x", self.Hash[:4])
+		return false
+	}
+	txHash := types.DeriveSha(types.Transactions(body.Transactions))
+	if header.TxHash != txHash {
+		glog.V(logger.Debug).Infof("ODR: header.TxHash %08x does not match received txHash %08x", header.TxHash[:4], txHash[:4])
+		return false
+	}
+	uncleHash := types.CalcUncleHash(body.Uncles)
+	if header.UncleHash != uncleHash {
+		glog.V(logger.Debug).Infof("ODR: header.UncleHash %08x does not match received uncleHash %08x", header.UncleHash[:4], uncleHash[:4])
+		return false
+	}
+	data, err := rlp.EncodeToBytes(body)
+	if err != nil {
+		glog.V(logger.Debug).Infof("ODR: body RLP encode error: %v", err)
+		return false
+	}
+	self.Rlp = data
+	glog.V(logger.Debug).Infof("ODR: validation successful")
+	return true
+}
+
+// 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 (self *ReceiptsRequest) GetCost(peer *peer) uint64 {
+	return peer.GetRequestCost(GetReceiptsMsg, 1)
+}
+
+// Request sends an ODR request to the LES network (implementation of LesOdrRequest)
+func (self *ReceiptsRequest) Request(reqID uint64, peer *peer) error {
+	glog.V(logger.Debug).Infof("ODR: requesting receipts for block %08x from peer %v", self.Hash[:4], peer.id)
+	return peer.RequestReceipts(reqID, self.GetCost(peer), []common.Hash{self.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 (self *ReceiptsRequest) Valid(db ethdb.Database, msg *Msg) bool {
+	glog.V(logger.Debug).Infof("ODR: validating receipts for block %08x", self.Hash[:4])
+	if msg.MsgType != MsgReceipts {
+		glog.V(logger.Debug).Infof("ODR: invalid message type")
+		return false
+	}
+	receipts := msg.Obj.([]types.Receipts)
+	if len(receipts) != 1 {
+		glog.V(logger.Debug).Infof("ODR: invalid number of entries: %d", len(receipts))
+		return false
+	}
+	hash := types.DeriveSha(receipts[0])
+	header := core.GetHeader(db, self.Hash, self.Number)
+	if header == nil {
+		glog.V(logger.Debug).Infof("ODR: header not found for block %08x", self.Hash[:4])
+		return false
+	}
+	if !bytes.Equal(header.ReceiptHash[:], hash[:]) {
+		glog.V(logger.Debug).Infof("ODR: header receipts hash %08x does not match calculated RLP hash %08x", header.ReceiptHash[:4], hash[:4])
+		return false
+	}
+	self.Receipts = receipts[0]
+	glog.V(logger.Debug).Infof("ODR: validation successful")
+	return true
+}
+
+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 (self *TrieRequest) GetCost(peer *peer) uint64 {
+	return peer.GetRequestCost(GetProofsMsg, 1)
+}
+
+// Request sends an ODR request to the LES network (implementation of LesOdrRequest)
+func (self *TrieRequest) Request(reqID uint64, peer *peer) error {
+	glog.V(logger.Debug).Infof("ODR: requesting trie root %08x key %08x from peer %v", self.Id.Root[:4], self.Key[:4], peer.id)
+	req := &ProofReq{
+		BHash:  self.Id.BlockHash,
+		AccKey: self.Id.AccKey,
+		Key:    self.Key,
+	}
+	return peer.RequestProofs(reqID, self.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 (self *TrieRequest) Valid(db ethdb.Database, msg *Msg) bool {
+	glog.V(logger.Debug).Infof("ODR: validating trie root %08x key %08x", self.Id.Root[:4], self.Key[:4])
+
+	if msg.MsgType != MsgProofs {
+		glog.V(logger.Debug).Infof("ODR: invalid message type")
+		return false
+	}
+	proofs := msg.Obj.([][]rlp.RawValue)
+	if len(proofs) != 1 {
+		glog.V(logger.Debug).Infof("ODR: invalid number of entries: %d", len(proofs))
+		return false
+	}
+	_, err := trie.VerifyProof(self.Id.Root, self.Key, proofs[0])
+	if err != nil {
+		glog.V(logger.Debug).Infof("ODR: merkle proof verification error: %v", err)
+		return false
+	}
+	self.Proof = proofs[0]
+	glog.V(logger.Debug).Infof("ODR: validation successful")
+	return true
+}
+
+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 (self *CodeRequest) GetCost(peer *peer) uint64 {
+	return peer.GetRequestCost(GetCodeMsg, 1)
+}
+
+// Request sends an ODR request to the LES network (implementation of LesOdrRequest)
+func (self *CodeRequest) Request(reqID uint64, peer *peer) error {
+	glog.V(logger.Debug).Infof("ODR: requesting node data for hash %08x from peer %v", self.Hash[:4], peer.id)
+	req := &CodeReq{
+		BHash:  self.Id.BlockHash,
+		AccKey: self.Id.AccKey,
+	}
+	return peer.RequestCode(reqID, self.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 (self *CodeRequest) Valid(db ethdb.Database, msg *Msg) bool {
+	glog.V(logger.Debug).Infof("ODR: validating node data for hash %08x", self.Hash[:4])
+	if msg.MsgType != MsgCode {
+		glog.V(logger.Debug).Infof("ODR: invalid message type")
+		return false
+	}
+	reply := msg.Obj.([][]byte)
+	if len(reply) != 1 {
+		glog.V(logger.Debug).Infof("ODR: invalid number of entries: %d", len(reply))
+		return false
+	}
+	data := reply[0]
+	hash := crypto.Sha3Hash(data)
+	if !bytes.Equal(self.Hash[:], hash[:]) {
+		glog.V(logger.Debug).Infof("ODR: requested hash %08x does not match received data hash %08x", self.Hash[:4], hash[:4])
+		return false
+	}
+	self.Data = data
+	glog.V(logger.Debug).Infof("ODR: validation successful")
+	return true
+}
+
+type ChtReq struct {
+	ChtNum, BlockNum, FromLevel uint64
+}
+
+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 (self *ChtRequest) GetCost(peer *peer) uint64 {
+	return peer.GetRequestCost(GetHeaderProofsMsg, 1)
+}
+
+// Request sends an ODR request to the LES network (implementation of LesOdrRequest)
+func (self *ChtRequest) Request(reqID uint64, peer *peer) error {
+	glog.V(logger.Debug).Infof("ODR: requesting CHT #%d block #%d from peer %v", self.ChtNum, self.BlockNum, peer.id)
+	req := &ChtReq{
+		ChtNum:   self.ChtNum,
+		BlockNum: self.BlockNum,
+	}
+	return peer.RequestHeaderProofs(reqID, self.GetCost(peer), []*ChtReq{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 (self *ChtRequest) Valid(db ethdb.Database, msg *Msg) bool {
+	glog.V(logger.Debug).Infof("ODR: validating CHT #%d block #%d", self.ChtNum, self.BlockNum)
+
+	if msg.MsgType != MsgHeaderProofs {
+		glog.V(logger.Debug).Infof("ODR: invalid message type")
+		return false
+	}
+	proofs := msg.Obj.([]ChtResp)
+	if len(proofs) != 1 {
+		glog.V(logger.Debug).Infof("ODR: invalid number of entries: %d", len(proofs))
+		return false
+	}
+	proof := proofs[0]
+	var encNumber [8]byte
+	binary.BigEndian.PutUint64(encNumber[:], self.BlockNum)
+	value, err := trie.VerifyProof(self.ChtRoot, encNumber[:], proof.Proof)
+	if err != nil {
+		glog.V(logger.Debug).Infof("ODR: CHT merkle proof verification error: %v", err)
+		return false
+	}
+	var node light.ChtNode
+	if err := rlp.DecodeBytes(value, &node); err != nil {
+		glog.V(logger.Debug).Infof("ODR: error decoding CHT node: %v", err)
+		return false
+	}
+	if node.Hash != proof.Header.Hash() {
+		glog.V(logger.Debug).Infof("ODR: CHT header hash does not match")
+		return false
+	}
+
+	self.Proof = proof.Proof
+	self.Header = proof.Header
+	self.Td = node.Td
+	glog.V(logger.Debug).Infof("ODR: validation successful")
+	return true
+}