This commit splits the eth package, separating the handling of eth and snap protocols. It also includes the capability to run snap sync (https://github.com/ethereum/devp2p/blob/master/caps/snap.md) , but does not enable it by default. Co-authored-by: Marius van der Wijden <m.vanderwijden@live.de> Co-authored-by: Martin Holst Swende <martin@swende.se>
		
			
				
	
	
		
			491 lines
		
	
	
		
			17 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			491 lines
		
	
	
		
			17 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
// Copyright 2020 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package snap
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import (
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	"bytes"
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	"fmt"
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	"github.com/ethereum/go-ethereum/common"
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	"github.com/ethereum/go-ethereum/core"
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	"github.com/ethereum/go-ethereum/core/state"
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	"github.com/ethereum/go-ethereum/light"
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	"github.com/ethereum/go-ethereum/log"
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	"github.com/ethereum/go-ethereum/p2p"
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	"github.com/ethereum/go-ethereum/p2p/enode"
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	"github.com/ethereum/go-ethereum/p2p/enr"
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	"github.com/ethereum/go-ethereum/rlp"
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	"github.com/ethereum/go-ethereum/trie"
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)
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const (
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	// softResponseLimit is the target maximum size of replies to data retrievals.
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	softResponseLimit = 2 * 1024 * 1024
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	// maxCodeLookups is the maximum number of bytecodes to serve. This number is
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	// there to limit the number of disk lookups.
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	maxCodeLookups = 1024
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	// stateLookupSlack defines the ratio by how much a state response can exceed
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	// the requested limit in order to try and avoid breaking up contracts into
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	// multiple packages and proving them.
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	stateLookupSlack = 0.1
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	// maxTrieNodeLookups is the maximum number of state trie nodes to serve. This
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	// number is there to limit the number of disk lookups.
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	maxTrieNodeLookups = 1024
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)
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// Handler is a callback to invoke from an outside runner after the boilerplate
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// exchanges have passed.
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type Handler func(peer *Peer) error
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// Backend defines the data retrieval methods to serve remote requests and the
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// callback methods to invoke on remote deliveries.
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type Backend interface {
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	// Chain retrieves the blockchain object to serve data.
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	Chain() *core.BlockChain
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	// RunPeer is invoked when a peer joins on the `eth` protocol. The handler
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	// should do any peer maintenance work, handshakes and validations. If all
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	// is passed, control should be given back to the `handler` to process the
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	// inbound messages going forward.
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	RunPeer(peer *Peer, handler Handler) error
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	// PeerInfo retrieves all known `snap` information about a peer.
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	PeerInfo(id enode.ID) interface{}
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	// Handle is a callback to be invoked when a data packet is received from
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	// the remote peer. Only packets not consumed by the protocol handler will
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	// be forwarded to the backend.
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	Handle(peer *Peer, packet Packet) error
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}
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// MakeProtocols constructs the P2P protocol definitions for `snap`.
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func MakeProtocols(backend Backend, dnsdisc enode.Iterator) []p2p.Protocol {
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	protocols := make([]p2p.Protocol, len(protocolVersions))
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	for i, version := range protocolVersions {
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		version := version // Closure
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		protocols[i] = p2p.Protocol{
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			Name:    protocolName,
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			Version: version,
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			Length:  protocolLengths[version],
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			Run: func(p *p2p.Peer, rw p2p.MsgReadWriter) error {
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				return backend.RunPeer(newPeer(version, p, rw), func(peer *Peer) error {
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					return handle(backend, peer)
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				})
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			},
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			NodeInfo: func() interface{} {
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				return nodeInfo(backend.Chain())
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			},
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			PeerInfo: func(id enode.ID) interface{} {
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				return backend.PeerInfo(id)
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			},
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			Attributes:     []enr.Entry{&enrEntry{}},
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			DialCandidates: dnsdisc,
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		}
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	}
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	return protocols
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}
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// handle is the callback invoked to manage the life cycle of a `snap` peer.
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// When this function terminates, the peer is disconnected.
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func handle(backend Backend, peer *Peer) error {
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	for {
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		if err := handleMessage(backend, peer); err != nil {
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			peer.Log().Debug("Message handling failed in `snap`", "err", err)
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			return err
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		}
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	}
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}
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// handleMessage is invoked whenever an inbound message is received from a
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// remote peer on the `spap` protocol. The remote connection is torn down upon
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// returning any error.
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func handleMessage(backend Backend, peer *Peer) error {
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	// Read the next message from the remote peer, and ensure it's fully consumed
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	msg, err := peer.rw.ReadMsg()
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	if err != nil {
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		return err
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	}
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	if msg.Size > maxMessageSize {
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		return fmt.Errorf("%w: %v > %v", errMsgTooLarge, msg.Size, maxMessageSize)
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	}
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	defer msg.Discard()
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	// Handle the message depending on its contents
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	switch {
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	case msg.Code == GetAccountRangeMsg:
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		// Decode the account retrieval request
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		var req GetAccountRangePacket
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		if err := msg.Decode(&req); err != nil {
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			return fmt.Errorf("%w: message %v: %v", errDecode, msg, err)
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		}
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		if req.Bytes > softResponseLimit {
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			req.Bytes = softResponseLimit
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		}
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		// Retrieve the requested state and bail out if non existent
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		tr, err := trie.New(req.Root, backend.Chain().StateCache().TrieDB())
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		if err != nil {
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			return p2p.Send(peer.rw, AccountRangeMsg, &AccountRangePacket{ID: req.ID})
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		}
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		it, err := backend.Chain().Snapshots().AccountIterator(req.Root, req.Origin)
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		if err != nil {
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			return p2p.Send(peer.rw, AccountRangeMsg, &AccountRangePacket{ID: req.ID})
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		}
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		// Iterate over the requested range and pile accounts up
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		var (
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			accounts []*AccountData
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			size     uint64
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			last     common.Hash
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		)
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		for it.Next() && size < req.Bytes {
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			hash, account := it.Hash(), common.CopyBytes(it.Account())
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			// Track the returned interval for the Merkle proofs
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			last = hash
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			// Assemble the reply item
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			size += uint64(common.HashLength + len(account))
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			accounts = append(accounts, &AccountData{
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				Hash: hash,
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				Body: account,
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			})
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			// If we've exceeded the request threshold, abort
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			if bytes.Compare(hash[:], req.Limit[:]) >= 0 {
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				break
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			}
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		}
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		it.Release()
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		// Generate the Merkle proofs for the first and last account
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		proof := light.NewNodeSet()
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		if err := tr.Prove(req.Origin[:], 0, proof); err != nil {
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			log.Warn("Failed to prove account range", "origin", req.Origin, "err", err)
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			return p2p.Send(peer.rw, AccountRangeMsg, &AccountRangePacket{ID: req.ID})
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		}
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		if last != (common.Hash{}) {
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			if err := tr.Prove(last[:], 0, proof); err != nil {
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				log.Warn("Failed to prove account range", "last", last, "err", err)
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				return p2p.Send(peer.rw, AccountRangeMsg, &AccountRangePacket{ID: req.ID})
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			}
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		}
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		var proofs [][]byte
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		for _, blob := range proof.NodeList() {
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			proofs = append(proofs, blob)
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		}
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		// Send back anything accumulated
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		return p2p.Send(peer.rw, AccountRangeMsg, &AccountRangePacket{
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			ID:       req.ID,
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			Accounts: accounts,
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			Proof:    proofs,
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		})
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	case msg.Code == AccountRangeMsg:
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		// A range of accounts arrived to one of our previous requests
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		res := new(AccountRangePacket)
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		if err := msg.Decode(res); err != nil {
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			return fmt.Errorf("%w: message %v: %v", errDecode, msg, err)
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		}
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		// Ensure the range is monotonically increasing
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		for i := 1; i < len(res.Accounts); i++ {
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			if bytes.Compare(res.Accounts[i-1].Hash[:], res.Accounts[i].Hash[:]) >= 0 {
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				return fmt.Errorf("accounts not monotonically increasing: #%d [%x] vs #%d [%x]", i-1, res.Accounts[i-1].Hash[:], i, res.Accounts[i].Hash[:])
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			}
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		}
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		return backend.Handle(peer, res)
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	case msg.Code == GetStorageRangesMsg:
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		// Decode the storage retrieval request
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		var req GetStorageRangesPacket
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		if err := msg.Decode(&req); err != nil {
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			return fmt.Errorf("%w: message %v: %v", errDecode, msg, err)
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		}
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		if req.Bytes > softResponseLimit {
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			req.Bytes = softResponseLimit
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		}
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		// TODO(karalabe): Do we want to enforce > 0 accounts and 1 account if origin is set?
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		// TODO(karalabe):   - Logging locally is not ideal as remote faulst annoy the local user
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		// TODO(karalabe):   - Dropping the remote peer is less flexible wrt client bugs (slow is better than non-functional)
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		// Calculate the hard limit at which to abort, even if mid storage trie
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		hardLimit := uint64(float64(req.Bytes) * (1 + stateLookupSlack))
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		// Retrieve storage ranges until the packet limit is reached
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		var (
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			slots  [][]*StorageData
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			proofs [][]byte
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			size   uint64
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		)
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		for _, account := range req.Accounts {
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			// If we've exceeded the requested data limit, abort without opening
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			// a new storage range (that we'd need to prove due to exceeded size)
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			if size >= req.Bytes {
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				break
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			}
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			// The first account might start from a different origin and end sooner
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			var origin common.Hash
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			if len(req.Origin) > 0 {
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				origin, req.Origin = common.BytesToHash(req.Origin), nil
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			}
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			var limit = common.HexToHash("0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff")
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			if len(req.Limit) > 0 {
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				limit, req.Limit = common.BytesToHash(req.Limit), nil
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			}
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			// Retrieve the requested state and bail out if non existent
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			it, err := backend.Chain().Snapshots().StorageIterator(req.Root, account, origin)
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			if err != nil {
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				return p2p.Send(peer.rw, StorageRangesMsg, &StorageRangesPacket{ID: req.ID})
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			}
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			// Iterate over the requested range and pile slots up
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			var (
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				storage []*StorageData
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				last    common.Hash
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			)
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			for it.Next() && size < hardLimit {
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				hash, slot := it.Hash(), common.CopyBytes(it.Slot())
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				// Track the returned interval for the Merkle proofs
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				last = hash
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				// Assemble the reply item
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				size += uint64(common.HashLength + len(slot))
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				storage = append(storage, &StorageData{
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					Hash: hash,
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					Body: slot,
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				})
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				// If we've exceeded the request threshold, abort
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				if bytes.Compare(hash[:], limit[:]) >= 0 {
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					break
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				}
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			}
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			slots = append(slots, storage)
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			it.Release()
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			// Generate the Merkle proofs for the first and last storage slot, but
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			// only if the response was capped. If the entire storage trie included
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			// in the response, no need for any proofs.
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			if origin != (common.Hash{}) || size >= hardLimit {
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				// Request started at a non-zero hash or was capped prematurely, add
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				// the endpoint Merkle proofs
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				accTrie, err := trie.New(req.Root, backend.Chain().StateCache().TrieDB())
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				if err != nil {
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					return p2p.Send(peer.rw, StorageRangesMsg, &StorageRangesPacket{ID: req.ID})
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				}
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				var acc state.Account
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				if err := rlp.DecodeBytes(accTrie.Get(account[:]), &acc); err != nil {
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					return p2p.Send(peer.rw, StorageRangesMsg, &StorageRangesPacket{ID: req.ID})
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				}
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				stTrie, err := trie.New(acc.Root, backend.Chain().StateCache().TrieDB())
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				if err != nil {
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					return p2p.Send(peer.rw, StorageRangesMsg, &StorageRangesPacket{ID: req.ID})
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				}
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				proof := light.NewNodeSet()
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				if err := stTrie.Prove(origin[:], 0, proof); err != nil {
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					log.Warn("Failed to prove storage range", "origin", req.Origin, "err", err)
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					return p2p.Send(peer.rw, StorageRangesMsg, &StorageRangesPacket{ID: req.ID})
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				}
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				if last != (common.Hash{}) {
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					if err := stTrie.Prove(last[:], 0, proof); err != nil {
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						log.Warn("Failed to prove storage range", "last", last, "err", err)
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						return p2p.Send(peer.rw, StorageRangesMsg, &StorageRangesPacket{ID: req.ID})
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					}
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				}
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				for _, blob := range proof.NodeList() {
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					proofs = append(proofs, blob)
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				}
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				// Proof terminates the reply as proofs are only added if a node
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				// refuses to serve more data (exception when a contract fetch is
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				// finishing, but that's that).
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				break
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			}
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		}
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		// Send back anything accumulated
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		return p2p.Send(peer.rw, StorageRangesMsg, &StorageRangesPacket{
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			ID:    req.ID,
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			Slots: slots,
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			Proof: proofs,
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		})
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	case msg.Code == StorageRangesMsg:
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		// A range of storage slots arrived to one of our previous requests
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		res := new(StorageRangesPacket)
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		if err := msg.Decode(res); err != nil {
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			return fmt.Errorf("%w: message %v: %v", errDecode, msg, err)
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		}
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		// Ensure the ranges ae monotonically increasing
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		for i, slots := range res.Slots {
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			for j := 1; j < len(slots); j++ {
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				if bytes.Compare(slots[j-1].Hash[:], slots[j].Hash[:]) >= 0 {
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					return fmt.Errorf("storage slots not monotonically increasing for account #%d: #%d [%x] vs #%d [%x]", i, j-1, slots[j-1].Hash[:], j, slots[j].Hash[:])
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				}
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			}
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		}
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		return backend.Handle(peer, res)
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						|
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						|
	case msg.Code == GetByteCodesMsg:
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						|
		// Decode bytecode retrieval request
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		var req GetByteCodesPacket
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		if err := msg.Decode(&req); err != nil {
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			return fmt.Errorf("%w: message %v: %v", errDecode, msg, err)
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		}
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						|
		if req.Bytes > softResponseLimit {
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			req.Bytes = softResponseLimit
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		}
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						|
		if len(req.Hashes) > maxCodeLookups {
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			req.Hashes = req.Hashes[:maxCodeLookups]
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		}
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						|
		// Retrieve bytecodes until the packet size limit is reached
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						|
		var (
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			codes [][]byte
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			bytes uint64
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		)
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						|
		for _, hash := range req.Hashes {
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						|
			if hash == emptyCode {
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				// Peers should not request the empty code, but if they do, at
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				// least sent them back a correct response without db lookups
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				codes = append(codes, []byte{})
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			} else if blob, err := backend.Chain().ContractCode(hash); err == nil {
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						|
				codes = append(codes, blob)
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						|
				bytes += uint64(len(blob))
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			}
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						|
			if bytes > req.Bytes {
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				break
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			}
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		}
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		// Send back anything accumulated
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		return p2p.Send(peer.rw, ByteCodesMsg, &ByteCodesPacket{
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			ID:    req.ID,
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			Codes: codes,
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		})
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						|
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						|
	case msg.Code == ByteCodesMsg:
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		// A batch of byte codes arrived to one of our previous requests
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						|
		res := new(ByteCodesPacket)
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						|
		if err := msg.Decode(res); err != nil {
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						|
			return fmt.Errorf("%w: message %v: %v", errDecode, msg, err)
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		}
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		return backend.Handle(peer, res)
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						|
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						|
	case msg.Code == GetTrieNodesMsg:
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						|
		// Decode trie node retrieval request
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						|
		var req GetTrieNodesPacket
 | 
						|
		if err := msg.Decode(&req); err != nil {
 | 
						|
			return fmt.Errorf("%w: message %v: %v", errDecode, msg, err)
 | 
						|
		}
 | 
						|
		if req.Bytes > softResponseLimit {
 | 
						|
			req.Bytes = softResponseLimit
 | 
						|
		}
 | 
						|
		// Make sure we have the state associated with the request
 | 
						|
		triedb := backend.Chain().StateCache().TrieDB()
 | 
						|
 | 
						|
		accTrie, err := trie.NewSecure(req.Root, triedb)
 | 
						|
		if err != nil {
 | 
						|
			// We don't have the requested state available, bail out
 | 
						|
			return p2p.Send(peer.rw, TrieNodesMsg, &TrieNodesPacket{ID: req.ID})
 | 
						|
		}
 | 
						|
		snap := backend.Chain().Snapshots().Snapshot(req.Root)
 | 
						|
		if snap == nil {
 | 
						|
			// We don't have the requested state snapshotted yet, bail out.
 | 
						|
			// In reality we could still serve using the account and storage
 | 
						|
			// tries only, but let's protect the node a bit while it's doing
 | 
						|
			// snapshot generation.
 | 
						|
			return p2p.Send(peer.rw, TrieNodesMsg, &TrieNodesPacket{ID: req.ID})
 | 
						|
		}
 | 
						|
		// Retrieve trie nodes until the packet size limit is reached
 | 
						|
		var (
 | 
						|
			nodes [][]byte
 | 
						|
			bytes uint64
 | 
						|
			loads int // Trie hash expansions to cound database reads
 | 
						|
		)
 | 
						|
		for _, pathset := range req.Paths {
 | 
						|
			switch len(pathset) {
 | 
						|
			case 0:
 | 
						|
				// Ensure we penalize invalid requests
 | 
						|
				return fmt.Errorf("%w: zero-item pathset requested", errBadRequest)
 | 
						|
 | 
						|
			case 1:
 | 
						|
				// If we're only retrieving an account trie node, fetch it directly
 | 
						|
				blob, resolved, err := accTrie.TryGetNode(pathset[0])
 | 
						|
				loads += resolved // always account database reads, even for failures
 | 
						|
				if err != nil {
 | 
						|
					break
 | 
						|
				}
 | 
						|
				nodes = append(nodes, blob)
 | 
						|
				bytes += uint64(len(blob))
 | 
						|
 | 
						|
			default:
 | 
						|
				// Storage slots requested, open the storage trie and retrieve from there
 | 
						|
				account, err := snap.Account(common.BytesToHash(pathset[0]))
 | 
						|
				loads++ // always account database reads, even for failures
 | 
						|
				if err != nil {
 | 
						|
					break
 | 
						|
				}
 | 
						|
				stTrie, err := trie.NewSecure(common.BytesToHash(account.Root), triedb)
 | 
						|
				loads++ // always account database reads, even for failures
 | 
						|
				if err != nil {
 | 
						|
					break
 | 
						|
				}
 | 
						|
				for _, path := range pathset[1:] {
 | 
						|
					blob, resolved, err := stTrie.TryGetNode(path)
 | 
						|
					loads += resolved // always account database reads, even for failures
 | 
						|
					if err != nil {
 | 
						|
						break
 | 
						|
					}
 | 
						|
					nodes = append(nodes, blob)
 | 
						|
					bytes += uint64(len(blob))
 | 
						|
 | 
						|
					// Sanity check limits to avoid DoS on the store trie loads
 | 
						|
					if bytes > req.Bytes || loads > maxTrieNodeLookups {
 | 
						|
						break
 | 
						|
					}
 | 
						|
				}
 | 
						|
			}
 | 
						|
			// Abort request processing if we've exceeded our limits
 | 
						|
			if bytes > req.Bytes || loads > maxTrieNodeLookups {
 | 
						|
				break
 | 
						|
			}
 | 
						|
		}
 | 
						|
		// Send back anything accumulated
 | 
						|
		return p2p.Send(peer.rw, TrieNodesMsg, &TrieNodesPacket{
 | 
						|
			ID:    req.ID,
 | 
						|
			Nodes: nodes,
 | 
						|
		})
 | 
						|
 | 
						|
	case msg.Code == TrieNodesMsg:
 | 
						|
		// A batch of trie nodes arrived to one of our previous requests
 | 
						|
		res := new(TrieNodesPacket)
 | 
						|
		if err := msg.Decode(res); err != nil {
 | 
						|
			return fmt.Errorf("%w: message %v: %v", errDecode, msg, err)
 | 
						|
		}
 | 
						|
		return backend.Handle(peer, res)
 | 
						|
 | 
						|
	default:
 | 
						|
		return fmt.Errorf("%w: %v", errInvalidMsgCode, msg.Code)
 | 
						|
	}
 | 
						|
}
 | 
						|
 | 
						|
// NodeInfo represents a short summary of the `snap` sub-protocol metadata
 | 
						|
// known about the host peer.
 | 
						|
type NodeInfo struct{}
 | 
						|
 | 
						|
// nodeInfo retrieves some `snap` protocol metadata about the running host node.
 | 
						|
func nodeInfo(chain *core.BlockChain) *NodeInfo {
 | 
						|
	return &NodeInfo{}
 | 
						|
}
 |