github.1485827954.workers.dev/ethereum/go-ethereum@v1.14.3/beacon/types/header.go (about)

     1  // Copyright 2022 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  // Package types implements a few types of the beacon chain for light client usage.
    18  package types
    19  
    20  import (
    21  	"crypto/sha256"
    22  	"encoding/binary"
    23  
    24  	"github.com/ethereum/go-ethereum/beacon/merkle"
    25  	"github.com/ethereum/go-ethereum/beacon/params"
    26  	"github.com/ethereum/go-ethereum/common"
    27  	zrntcommon "github.com/protolambda/zrnt/eth2/beacon/common"
    28  )
    29  
    30  //go:generate go run github.com/fjl/gencodec -type Header -field-override headerMarshaling -out gen_header_json.go
    31  
    32  const (
    33  	headerIndexSlot          = 8
    34  	headerIndexProposerIndex = 9
    35  	headerIndexParentRoot    = 10
    36  	headerIndexStateRoot     = 11
    37  	headerIndexBodyRoot      = 12
    38  )
    39  
    40  // Header defines a beacon header.
    41  //
    42  // See data structure definition here:
    43  // https://github.com/ethereum/consensus-specs/blob/dev/specs/phase0/beacon-chain.md#beaconblockheader
    44  type Header struct {
    45  	// Monotonically increasing slot number for the beacon block (may be gapped)
    46  	Slot uint64 `gencodec:"required" json:"slot"`
    47  
    48  	// Index into the validator table who created the beacon block
    49  	ProposerIndex uint64 `gencodec:"required" json:"proposer_index"`
    50  
    51  	// SSZ hash of the parent beacon header
    52  	ParentRoot common.Hash `gencodec:"required" json:"parent_root"`
    53  
    54  	// SSZ hash of the beacon state (https://github.com/ethereum/consensus-specs/blob/dev/specs/bellatrix/beacon-chain.md#beacon-state)
    55  	StateRoot common.Hash `gencodec:"required" json:"state_root"`
    56  
    57  	// SSZ hash of the beacon block body (https://github.com/ethereum/consensus-specs/blob/dev/specs/bellatrix/beacon-chain.md#beaconblockbody)
    58  	BodyRoot common.Hash `gencodec:"required" json:"body_root"`
    59  }
    60  
    61  func headerFromZRNT(zh *zrntcommon.BeaconBlockHeader) Header {
    62  	return Header{
    63  		Slot:          uint64(zh.Slot),
    64  		ProposerIndex: uint64(zh.ProposerIndex),
    65  		ParentRoot:    common.Hash(zh.ParentRoot),
    66  		StateRoot:     common.Hash(zh.StateRoot),
    67  		BodyRoot:      common.Hash(zh.BodyRoot),
    68  	}
    69  }
    70  
    71  // headerMarshaling is a field type overrides for gencodec.
    72  type headerMarshaling struct {
    73  	Slot          common.Decimal
    74  	ProposerIndex common.Decimal
    75  }
    76  
    77  // Hash calculates the block root of the header.
    78  //
    79  // TODO(zsfelfoldi): Remove this when an SSZ encoder lands.
    80  func (h *Header) Hash() common.Hash {
    81  	var values [16]merkle.Value // values corresponding to indices 8 to 15 of the beacon header tree
    82  	binary.LittleEndian.PutUint64(values[headerIndexSlot][:8], h.Slot)
    83  	binary.LittleEndian.PutUint64(values[headerIndexProposerIndex][:8], h.ProposerIndex)
    84  	values[headerIndexParentRoot] = merkle.Value(h.ParentRoot)
    85  	values[headerIndexStateRoot] = merkle.Value(h.StateRoot)
    86  	values[headerIndexBodyRoot] = merkle.Value(h.BodyRoot)
    87  	hasher := sha256.New()
    88  	for i := 7; i > 0; i-- {
    89  		hasher.Reset()
    90  		hasher.Write(values[i*2][:])
    91  		hasher.Write(values[i*2+1][:])
    92  		hasher.Sum(values[i][:0])
    93  	}
    94  	return common.Hash(values[1])
    95  }
    96  
    97  // Epoch returns the epoch the header belongs to.
    98  func (h *Header) Epoch() uint64 {
    99  	return h.Slot / params.EpochLength
   100  }
   101  
   102  // SyncPeriod returns the sync period the header belongs to.
   103  func (h *Header) SyncPeriod() uint64 {
   104  	return SyncPeriod(h.Slot)
   105  }
   106  
   107  // SyncPeriodStart returns the first slot of the given period.
   108  func SyncPeriodStart(period uint64) uint64 {
   109  	return period * params.SyncPeriodLength
   110  }
   111  
   112  // SyncPeriod returns the sync period that the given slot belongs to.
   113  func SyncPeriod(slot uint64) uint64 {
   114  	return slot / params.SyncPeriodLength
   115  }
   116  
   117  // SignedHeader represents a beacon header signed by a sync committee.
   118  //
   119  // This structure is created from either an optimistic update or an instant update:
   120  //   - https://github.com/ethereum/consensus-specs/blob/dev/specs/altair/light-client/sync-protocol.md#lightclientoptimisticupdate
   121  //   - https://github.com/zsfelfoldi/beacon-APIs/blob/instant_update/apis/beacon/light_client/instant_update.yaml
   122  type SignedHeader struct {
   123  	// Beacon header being signed
   124  	Header Header
   125  
   126  	// Sync committee BLS signature aggregate
   127  	Signature SyncAggregate
   128  
   129  	// Slot in which the signature has been created (newer than Header.Slot,
   130  	// determines the signing sync committee)
   131  	SignatureSlot uint64
   132  }