1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
package contracts
import (
"bytes"
"errors"
"fmt"
"io"
"math/big"
"github.com/ethereum-optimism/optimism/op-service/predeploys"
"github.com/ethereum-optimism/optimism/op-service/solabi"
"github.com/ethereum-optimism/optimism/op-service/sources/batching"
backendTypes "github.com/ethereum-optimism/optimism/op-supervisor/supervisor/backend/types"
"github.com/ethereum-optimism/optimism/op-supervisor/supervisor/types"
"github.com/ethereum-optimism/optimism/packages/contracts-bedrock/snapshots"
"github.com/ethereum/go-ethereum/common"
ethTypes "github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/crypto"
)
const (
eventExecutingMessage = "ExecutingMessage"
)
var (
ErrEventNotFound = errors.New("event not found")
)
type contractIdentifier struct {
// Origin represents the address that initiated the message
// it is used in combination with the MsgHash to uniquely identify a message
// and is hashed into the log hash, not stored directly.
Origin common.Address
LogIndex *big.Int
BlockNumber *big.Int
ChainId *big.Int
Timestamp *big.Int
}
type CrossL2Inbox struct {
contract *batching.BoundContract
}
func NewCrossL2Inbox() *CrossL2Inbox {
abi := snapshots.LoadCrossL2InboxABI()
return &CrossL2Inbox{
contract: batching.NewBoundContract(abi, predeploys.CrossL2InboxAddr),
}
}
func (i *CrossL2Inbox) DecodeExecutingMessageLog(l *ethTypes.Log) (backendTypes.ExecutingMessage, error) {
if l.Address != i.contract.Addr() {
return backendTypes.ExecutingMessage{}, fmt.Errorf("%w: log not from CrossL2Inbox", ErrEventNotFound)
}
// use DecodeEvent to check the name of the event
// but the actual decoding is done manually to extract the contract identifier
name, _, err := i.contract.DecodeEvent(l)
if errors.Is(err, batching.ErrUnknownEvent) {
return backendTypes.ExecutingMessage{}, fmt.Errorf("%w: %v", ErrEventNotFound, err.Error())
} else if err != nil {
return backendTypes.ExecutingMessage{}, fmt.Errorf("failed to decode event: %w", err)
}
if name != eventExecutingMessage {
return backendTypes.ExecutingMessage{}, fmt.Errorf("%w: event %v not an ExecutingMessage event", ErrEventNotFound, name)
}
// the second topic is the hash of the payload (the first is the event ID)
msgHash := l.Topics[1]
// the first 32 bytes of the data are the msgHash, so we skip them
identifierBytes := bytes.NewReader(l.Data[32:])
identifier, err := identifierFromBytes(identifierBytes)
if err != nil {
return backendTypes.ExecutingMessage{}, fmt.Errorf("failed to read contract identifier: %w", err)
}
chainID, err := types.ChainIDFromBig(identifier.ChainId).ToUInt32()
if err != nil {
return backendTypes.ExecutingMessage{}, fmt.Errorf("failed to convert chain ID %v to uint32: %w", identifier.ChainId, err)
}
hash := payloadHashToLogHash(msgHash, identifier.Origin)
return backendTypes.ExecutingMessage{
Chain: chainID,
Hash: hash,
BlockNum: identifier.BlockNumber.Uint64(),
LogIdx: uint32(identifier.LogIndex.Uint64()),
Timestamp: identifier.Timestamp.Uint64(),
}, nil
}
// identifierFromBytes reads a contract identifier from a byte stream.
// it follows the spec and matches the CrossL2Inbox.json definition,
// rather than relying on reflection, as that can be error-prone regarding struct ordering
func identifierFromBytes(identifierBytes io.Reader) (contractIdentifier, error) {
origin, err := solabi.ReadAddress(identifierBytes)
if err != nil {
return contractIdentifier{}, fmt.Errorf("failed to read origin address: %w", err)
}
originAddr := common.BytesToAddress(origin[:])
blockNumber, err := solabi.ReadUint256(identifierBytes)
if err != nil {
return contractIdentifier{}, fmt.Errorf("failed to read block number: %w", err)
}
logIndex, err := solabi.ReadUint256(identifierBytes)
if err != nil {
return contractIdentifier{}, fmt.Errorf("failed to read log index: %w", err)
}
timestamp, err := solabi.ReadUint256(identifierBytes)
if err != nil {
return contractIdentifier{}, fmt.Errorf("failed to read timestamp: %w", err)
}
chainID, err := solabi.ReadUint256(identifierBytes)
if err != nil {
return contractIdentifier{}, fmt.Errorf("failed to read chain ID: %w", err)
}
return contractIdentifier{
Origin: originAddr,
BlockNumber: blockNumber,
LogIndex: logIndex,
Timestamp: timestamp,
ChainId: chainID,
}, nil
}
// payloadHashToLogHash converts the payload hash to the log hash
// it is the concatenation of the log's address and the hash of the log's payload,
// which is then hashed again. This is the hash that is stored in the log storage.
// The logHash can then be used to traverse from the executing message
// to the log the referenced initiating message.
// TODO: this function is duplicated between contracts and backend/source/log_processor.go
// to avoid a circular dependency. It should be reorganized to avoid this duplication.
func payloadHashToLogHash(payloadHash common.Hash, addr common.Address) backendTypes.TruncatedHash {
msg := make([]byte, 0, 2*common.HashLength)
msg = append(msg, addr.Bytes()...)
msg = append(msg, payloadHash.Bytes()...)
return backendTypes.TruncateHash(crypto.Keccak256Hash(msg))
}