go-ethereum/core/stateless/encoding.go
jwasinger ed8fd0ac09
all: stateless witness builder and (self-)cross validator (#29719)
* all: add stateless verifications

* all: simplify witness and integrate it into live geth

---------

Co-authored-by: Péter Szilágyi <peterke@gmail.com>
2024-06-25 14:48:08 +03:00

130 lines
4.0 KiB
Go

// Copyright 2024 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 stateless
import (
"bytes"
"errors"
"fmt"
"io"
"slices"
"github.com/ethereum/go-ethereum/common/hexutil"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/rlp"
)
//go:generate go run github.com/fjl/gencodec -type extWitness -field-override extWitnessMarshalling -out gen_encoding_json.go
// toExtWitness converts our internal witness representation to the consensus one.
func (w *Witness) toExtWitness() *extWitness {
ext := &extWitness{
Block: w.Block,
Headers: w.Headers,
}
ext.Codes = make([][]byte, 0, len(w.Codes))
for code := range w.Codes {
ext.Codes = append(ext.Codes, []byte(code))
}
slices.SortFunc(ext.Codes, bytes.Compare)
ext.State = make([][]byte, 0, len(w.State))
for node := range w.State {
ext.State = append(ext.State, []byte(node))
}
slices.SortFunc(ext.State, bytes.Compare)
return ext
}
// fromExtWitness converts the consensus witness format into our internal one.
func (w *Witness) fromExtWitness(ext *extWitness) error {
w.Block, w.Headers = ext.Block, ext.Headers
w.Codes = make(map[string]struct{}, len(ext.Codes))
for _, code := range ext.Codes {
w.Codes[string(code)] = struct{}{}
}
w.State = make(map[string]struct{}, len(ext.State))
for _, node := range ext.State {
w.State[string(node)] = struct{}{}
}
return w.sanitize()
}
// MarshalJSON marshals a witness as JSON.
func (w *Witness) MarshalJSON() ([]byte, error) {
return w.toExtWitness().MarshalJSON()
}
// EncodeRLP serializes a witness as RLP.
func (w *Witness) EncodeRLP(wr io.Writer) error {
return rlp.Encode(wr, w.toExtWitness())
}
// UnmarshalJSON unmarshals from JSON.
func (w *Witness) UnmarshalJSON(input []byte) error {
var ext extWitness
if err := ext.UnmarshalJSON(input); err != nil {
return err
}
return w.fromExtWitness(&ext)
}
// DecodeRLP decodes a witness from RLP.
func (w *Witness) DecodeRLP(s *rlp.Stream) error {
var ext extWitness
if err := s.Decode(&ext); err != nil {
return err
}
return w.fromExtWitness(&ext)
}
// sanitize checks for some mandatory fields in the witness after decoding so
// the rest of the code can assume invariants and doesn't have to deal with
// corrupted data.
func (w *Witness) sanitize() error {
// Verify that the "parent" header (i.e. index 0) is available, and is the
// true parent of the block-to-be executed, since we use that to link the
// current block to the pre-state.
if len(w.Headers) == 0 {
return errors.New("parent header (for pre-root hash) missing")
}
for i, header := range w.Headers {
if header == nil {
return fmt.Errorf("witness header nil at position %d", i)
}
}
if w.Headers[0].Hash() != w.Block.ParentHash() {
return fmt.Errorf("parent hash different: witness %v, block parent %v", w.Headers[0].Hash(), w.Block.ParentHash())
}
return nil
}
// extWitness is a witness RLP encoding for transferring across clients.
type extWitness struct {
Block *types.Block `json:"block" gencodec:"required"`
Headers []*types.Header `json:"headers" gencodec:"required"`
Codes [][]byte `json:"codes"`
State [][]byte `json:"state"`
}
// extWitnessMarshalling defines the hex marshalling types for a witness.
type extWitnessMarshalling struct {
Codes []hexutil.Bytes
State []hexutil.Bytes
}