path: root/les/odr_requests.go

// 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 (
    "bytes"
    "encoding/binary"
    "fmt"

    "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/log"
    "github.com/ethereum/go-ethereum/rlp"
    "github.com/ethereum/go-ethereum/trie"
)

type LesOdrRequest interface {
    GetCost(*peer) uint64
    CanSend(*peer) bool
    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)
}

// CanSend tells if a certain peer is suitable for serving the given request
func (self *BlockRequest) CanSend(peer *peer) bool {
    return peer.HasBlock(self.Hash, self.Number)
}

// Request sends an ODR request to the LES network (implementation of LesOdrRequest)
func (self *BlockRequest) Request(reqID uint64, peer *peer) error {
    log.Debug(fmt.Sprintf("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 {
    log.Debug(fmt.Sprintf("ODR: validating body of block %08x", self.Hash[:4]))
    if msg.MsgType != MsgBlockBodies {
        log.Debug(fmt.Sprintf("ODR: invalid message type"))
        return false
    }
    bodies := msg.Obj.([]*types.Body)
    if len(bodies) != 1 {
        log.Debug(fmt.Sprintf("ODR: invalid number of entries: %d", len(bodies)))
        return false
    }
    body := bodies[0]
    header := core.GetHeader(db, self.Hash, self.Number)
    if header == nil {
        log.Debug(fmt.Sprintf("ODR: header not found for block %08x", self.Hash[:4]))
        return false
    }
    txHash := types.DeriveSha(types.Transactions(body.Transactions))
    if header.TxHash != txHash {
        log.Debug(fmt.Sprintf("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 {
        log.Debug(fmt.Sprintf("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 {
        log.Debug(fmt.Sprintf("ODR: body RLP encode error: %v", err))
        return false
    }
    self.Rlp = data
    log.Debug(fmt.Sprintf("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)
}

// CanSend tells if a certain peer is suitable for serving the given request
func (self *ReceiptsRequest) CanSend(peer *peer) bool {
    return peer.HasBlock(self.Hash, self.Number)
}

// Request sends an ODR request to the LES network (implementation of LesOdrRequest)
func (self *ReceiptsRequest) Request(reqID uint64, peer *peer) error {
    log.Debug(fmt.Sprintf("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 {
    log.Debug(fmt.Sprintf("ODR: validating receipts for block %08x", self.Hash[:4]))
    if msg.MsgType != MsgReceipts {
        log.Debug(fmt.Sprintf("ODR: invalid message type"))
        return false
    }
    receipts := msg.Obj.([]types.Receipts)
    if len(receipts) != 1 {
        log.Debug(fmt.Sprintf("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 {
        log.Debug(fmt.Sprintf("ODR: header not found for block %08x", self.Hash[:4]))
        return false
    }
    if !bytes.Equal(header.ReceiptHash[:], hash[:]) {
        log.Debug(fmt.Sprintf("ODR: header receipts hash %08x does not match calculated RLP hash %08x", header.ReceiptHash[:4], hash[:4]))
        return false
    }
    self.Receipts = receipts[0]
    log.Debug(fmt.Sprintf("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)
}

// CanSend tells if a certain peer is suitable for serving the given request
func (self *TrieRequest) CanSend(peer *peer) bool {
    return peer.HasBlock(self.Id.BlockHash, self.Id.BlockNumber)
}

// Request sends an ODR request to the LES network (implementation of LesOdrRequest)
func (self *TrieRequest) Request(reqID uint64, peer *peer) error {
    log.Debug(fmt.Sprintf("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 {
    log.Debug(fmt.Sprintf("ODR: validating trie root %08x key %08x", self.Id.Root[:4], self.Key[:4]))

    if msg.MsgType != MsgProofs {
        log.Debug(fmt.Sprintf("ODR: invalid message type"))
        return false
    }
    proofs := msg.Obj.([][]rlp.RawValue)
    if len(proofs) != 1 {
        log.Debug(fmt.Sprintf("ODR: invalid number of entries: %d", len(proofs)))
        return false
    }
    _, err := trie.VerifyProof(self.Id.Root, self.Key, proofs[0])
    if err != nil {
        log.Debug(fmt.Sprintf("ODR: merkle proof verification error: %v", err))
        return false
    }
    self.Proof = proofs[0]
    log.Debug(fmt.Sprintf("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)
}

// CanSend tells if a certain peer is suitable for serving the given request
func (self *CodeRequest) CanSend(peer *peer) bool {
    return peer.HasBlock(self.Id.BlockHash, self.Id.BlockNumber)
}

// Request sends an ODR request to the LES network (implementation of LesOdrRequest)
func (self *CodeRequest) Request(reqID uint64, peer *peer) error {
    log.Debug(fmt.Sprintf("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 {
    log.Debug(fmt.Sprintf("ODR: validating node data for hash %08x", self.Hash[:4]))
    if msg.MsgType != MsgCode {
        log.Debug(fmt.Sprintf("ODR: invalid message type"))
        return false
    }
    reply := msg.Obj.([][]byte)
    if len(reply) != 1 {
        log.Debug(fmt.Sprintf("ODR: invalid number of entries: %d", len(reply)))
        return false
    }
    data := reply[0]
    if hash := crypto.Keccak256Hash(data); self.Hash != hash {
        log.Debug(fmt.Sprintf("ODR: requested hash %08x does not match received data hash %08x", self.Hash[:4], hash[:4]))
        return false
    }
    self.Data = data
    log.Debug(fmt.Sprintf("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)
}

// CanSend tells if a certain peer is suitable for serving the given request
func (self *ChtRequest) CanSend(peer *peer) bool {
    peer.lock.RLock()
    defer peer.lock.RUnlock()

    return self.ChtNum <= (peer.headInfo.Number-light.ChtConfirmations)/light.ChtFrequency
}

// Request sends an ODR request to the LES network (implementation of LesOdrRequest)
func (self *ChtRequest) Request(reqID uint64, peer *peer) error {
    log.Debug(fmt.Sprintf("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 {
    log.Debug(fmt.Sprintf("ODR: validating CHT #%d block #%d", self.ChtNum, self.BlockNum))

    if msg.MsgType != MsgHeaderProofs {
        log.Debug(fmt.Sprintf("ODR: invalid message type"))
        return false
    }
    proofs := msg.Obj.([]ChtResp)
    if len(proofs) != 1 {
        log.Debug(fmt.Sprintf("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 {
        log.Debug(fmt.Sprintf("ODR: CHT merkle proof verification error: %v", err))
        return false
    }
    var node light.ChtNode
    if err := rlp.DecodeBytes(value, &node); err != nil {
        log.Debug(fmt.Sprintf("ODR: error decoding CHT node: %v", err))
        return false
    }
    if node.Hash != proof.Header.Hash() {
        log.Debug(fmt.Sprintf("ODR: CHT header hash does not match"))
        return false
    }

    self.Proof = proof.Proof
    self.Header = proof.Header
    self.Td = node.Td
    log.Debug(fmt.Sprintf("ODR: validation successful"))
    return true
}