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multi: USDC Bridge between eth and polygon
Implements the CCTP protocol to bridge native USDC between eth and polygon.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,289 @@ | ||
| package eth | ||
|
|
||
| import ( | ||
| "context" | ||
| "encoding/hex" | ||
| "encoding/json" | ||
| "fmt" | ||
| "io" | ||
| "math/big" | ||
| "net/http" | ||
| "strings" | ||
|
|
||
| "decred.org/dcrdex/dex" | ||
| "decred.org/dcrdex/dex/encode" | ||
| "decred.org/dcrdex/dex/networks/erc20" | ||
| "decred.org/dcrdex/dex/networks/erc20/cctp" | ||
| "github.com/ethereum/go-ethereum/accounts/abi/bind" | ||
| "github.com/ethereum/go-ethereum/common" | ||
| "github.com/ethereum/go-ethereum/core/types" | ||
| "github.com/ethereum/go-ethereum/crypto" | ||
| ) | ||
|
|
||
| var ( | ||
| usdcEthID, _ = dex.BipSymbolID("usdc.eth") | ||
| usdcPolygonID, _ = dex.BipSymbolID("usdc.polygon") | ||
|
|
||
| // burn for deposit generally requires 102k-103k gas | ||
| burnForDepositGas uint64 = 160_000 | ||
| // message received generally requires ~142k, but if this is the first | ||
| // time the user owns this asset, it will be ~160k | ||
| messageReceivedGas uint64 = 210_000 | ||
| ) | ||
|
|
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| type usdcBridgeInfo struct { | ||
| tokenMessengerAddr common.Address | ||
| messageTransmitterAddr common.Address | ||
| domainID uint32 | ||
| } | ||
|
|
||
| var usdcBridgeInfos = map[uint32]map[dex.Network]*usdcBridgeInfo{ | ||
| usdcEthID: { | ||
| dex.Mainnet: { | ||
| tokenMessengerAddr: common.HexToAddress("0xbd3fa81b58ba92a82136038b25adec7066af3155"), | ||
| messageTransmitterAddr: common.HexToAddress("0x0a992d191deec32afe36203ad87d7d289a738f81"), | ||
| domainID: 0, | ||
| }, | ||
| dex.Testnet: { | ||
| tokenMessengerAddr: common.HexToAddress("0x9f3B8679c73C2Fef8b59B4f3444d4e156fb70AA5"), | ||
| messageTransmitterAddr: common.HexToAddress("0x7865fAfC2db2093669d92c0F33AeEF291086BEFD"), | ||
| domainID: 0, | ||
| }, | ||
| }, | ||
| usdcPolygonID: { | ||
| dex.Mainnet: { | ||
| tokenMessengerAddr: common.HexToAddress("0x9daF8c91AEFAE50b9c0E69629D3F6Ca40cA3B3FE"), | ||
| messageTransmitterAddr: common.HexToAddress("0xF3be9355363857F3e001be68856A2f96b4C39Ba9"), | ||
| domainID: 7, | ||
| }, | ||
| dex.Testnet: { | ||
| tokenMessengerAddr: common.HexToAddress("0x9f3B8679c73C2Fef8b59B4f3444d4e156fb70AA5"), | ||
| messageTransmitterAddr: common.HexToAddress("0x7865fAfC2db2093669d92c0F33AeEF291086BEFD"), | ||
| domainID: 7, | ||
| }, | ||
| }, | ||
| } | ||
|
|
||
| var usdcBridgeAttestationUrl = map[dex.Network]string{ | ||
| dex.Mainnet: "https://iris-api.circle.com/attestations/", | ||
| dex.Testnet: "https://iris-api-sandbox.circle.com/attestations/", | ||
| } | ||
|
|
||
| func getUsdcBridgeInfo(assetID uint32, net dex.Network) *usdcBridgeInfo { | ||
| assetBridgeInfo, found := usdcBridgeInfos[assetID] | ||
| if !found { | ||
| return nil | ||
| } | ||
|
|
||
| return assetBridgeInfo[net] | ||
| } | ||
|
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| // usdcBridge implements Circle's CCTP protocol to allow bridging native usdc | ||
| // between chains. | ||
| // | ||
| // https://developers.circle.com/stablecoins/docs/cctp-getting-started | ||
| // | ||
| // The bridge works using the following steps: | ||
| // | ||
| // 1. Call the "TokenMessenger" contract to burn the USDC on the source chain. | ||
| // The "TokenMessenger" contract must be approved to spend the USDC. The | ||
| // "depositForBurn" method will emit a "MessageSent" event. | ||
| // 2. After a certain number of confirmations, use the hash of the message in | ||
| // the emitted "MessageSent" event and retrieve an attestation from Circle's | ||
| // API. | ||
| // 3. Use the message and attestation to call the "receiveMessage" function on the | ||
| // target chain's "MessageTransmitter" contract to mint the USDC on the target | ||
| // chain. | ||
| type usdcBridge struct { | ||
| tokenMessenger *cctp.TokenMessenger | ||
| tokenMessengerAddr common.Address | ||
| messasgeTransmitter *cctp.MessageTransmitter | ||
| messageTransmitterAddr common.Address | ||
| tokenContract *erc20.IERC20 | ||
| tokenAddress common.Address | ||
| cb bind.ContractBackend | ||
| attestationUrl string | ||
| net dex.Network | ||
| } | ||
|
|
||
| func newUsdcBrdge(assetID uint32, net dex.Network, tokenAddress common.Address, cb bind.ContractBackend) (*usdcBridge, error) { | ||
| bridgeInfo := getUsdcBridgeInfo(assetID, net) | ||
| if bridgeInfo == nil { | ||
| return nil, fmt.Errorf("usdc bridge info not found for assetID %d and network %s", assetID, net) | ||
| } | ||
|
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| attestationUrl, found := usdcBridgeAttestationUrl[net] | ||
| if !found { | ||
| return nil, fmt.Errorf("attestation url not found for network %s", net) | ||
| } | ||
|
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||
| messageTransmitter, err := cctp.NewMessageTransmitter(bridgeInfo.messageTransmitterAddr, cb) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
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| tokenMessenger, err := cctp.NewTokenMessenger(bridgeInfo.tokenMessengerAddr, cb) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
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| tokenContract, err := erc20.NewIERC20(tokenAddress, cb) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
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| return &usdcBridge{ | ||
| tokenMessenger: tokenMessenger, | ||
| tokenMessengerAddr: bridgeInfo.tokenMessengerAddr, | ||
| messasgeTransmitter: messageTransmitter, | ||
| messageTransmitterAddr: bridgeInfo.messageTransmitterAddr, | ||
| tokenAddress: tokenAddress, | ||
| tokenContract: tokenContract, | ||
| cb: cb, | ||
| net: net, | ||
| attestationUrl: attestationUrl, | ||
| }, nil | ||
| } | ||
|
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||
| // bridgeContractAddr returns the address of the bridge contract. | ||
| func (b *usdcBridge) bridgeContractAddr() common.Address { | ||
| return b.tokenMessengerAddr | ||
| } | ||
|
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||
| // bridgeContractAllowance returns the amount that the bridge contract is | ||
| // allowed to spend on behalf of the user. | ||
| func (b *usdcBridge) bridgeContractAllowance(ctx context.Context, addr common.Address) (*big.Int, error) { | ||
| _, pendingUnavailable := b.cb.(*multiRPCClient) | ||
| callOpts := &bind.CallOpts{ | ||
| Pending: !pendingUnavailable, | ||
| From: addr, | ||
| Context: ctx, | ||
| } | ||
| return b.tokenContract.Allowance(callOpts, addr, b.tokenMessengerAddr) | ||
| } | ||
|
|
||
| // approveBridgeContract approves the bridge contract to spend the given amount | ||
| // of the token on behalf of the user. | ||
| func (b *usdcBridge) approveBridgeContract(txOpts *bind.TransactOpts, amount *big.Int) (*types.Transaction, error) { | ||
| return b.tokenContract.Approve(txOpts, b.tokenMessengerAddr, amount) | ||
| } | ||
|
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||
| // depositForBurn burns the given amount of the token on the source chain to | ||
| // bridge it to the destination chain. | ||
| func (b *usdcBridge) depositForBurn(txOpts *bind.TransactOpts, destAssetID uint32, addr common.Address, amount *big.Int) (*types.Transaction, error) { | ||
| destBridgeInfo := getUsdcBridgeInfo(destAssetID, b.net) | ||
| if destBridgeInfo == nil { | ||
| return nil, fmt.Errorf("usdc bridge info not found for assetID %d and network %s", destAssetID, b.net) | ||
| } | ||
|
|
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| var recipient [32]byte | ||
| copy(recipient[12:], addr[:]) | ||
|
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| return b.tokenMessenger.DepositForBurn(txOpts, amount, destBridgeInfo.domainID, recipient, b.tokenAddress) | ||
| } | ||
|
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||
| // usdcMintInfo is the data required to mint the USDC on the destination chain. | ||
| type usdcMintInfo struct { | ||
| attestation []byte | ||
| message []byte | ||
| } | ||
|
|
||
| func (u *usdcMintInfo) serialize() []byte { | ||
| return encode.BuildyBytes{0}. | ||
| AddData(u.attestation). | ||
| AddData(u.message) | ||
| } | ||
|
|
||
| func deserializeUsdcMintInfo(b []byte) (*usdcMintInfo, error) { | ||
| ver, pushes, err := encode.DecodeBlob(b) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
|
||
| if ver != 0 { | ||
| return nil, fmt.Errorf("invalid version %d", ver) | ||
| } | ||
|
|
||
| if len(pushes) != 2 { | ||
| return nil, fmt.Errorf("expected 2 pushes, got %d", len(pushes)) | ||
| } | ||
|
|
||
| return &usdcMintInfo{ | ||
| attestation: pushes[0], | ||
| message: pushes[1], | ||
| }, nil | ||
| } | ||
|
|
||
| // getMintInfo retrieves the message from the receipt of the depositForBurn | ||
| // call, and then retrieves the attestation from Circle's API. It returns the | ||
| // serialized data required to mint the USDC on the destination chain. | ||
| func (b *usdcBridge) getMintInfo(ctx context.Context, receipt *types.Receipt) ([]byte, error) { | ||
| var msg []byte | ||
| for _, log := range receipt.Logs { | ||
| messageSent, err := b.messasgeTransmitter.ParseMessageSent(*log) | ||
| if err != nil { | ||
| continue | ||
| } | ||
| msg = messageSent.Message | ||
| break | ||
| } | ||
| if msg == nil { | ||
| return nil, fmt.Errorf("no message sent event found in the receipt") | ||
| } | ||
|
|
||
| msgHash := "0x" + hex.EncodeToString(crypto.Keccak256(msg)) | ||
| url := fmt.Sprintf("%s%s", b.attestationUrl, msgHash) | ||
| req, err := http.NewRequestWithContext(ctx, "GET", url, nil) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
|
||
| resp, err := http.DefaultClient.Do(req) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| defer resp.Body.Close() | ||
|
|
||
| if resp.StatusCode != http.StatusOK { | ||
| return nil, fmt.Errorf("attestation request failed with status %d", resp.StatusCode) | ||
| } | ||
|
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| reader := io.LimitReader(resp.Body, 1<<22) | ||
| r, err := io.ReadAll(reader) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| attestationResponse := struct { | ||
| Attestation string `json:"attestation"` | ||
| Status string `json:"status"` | ||
| }{} | ||
| err = json.Unmarshal(r, &attestationResponse) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
|
||
| if attestationResponse.Status != "complete" { | ||
| return nil, fmt.Errorf("attestation is still pending") | ||
| } | ||
|
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| attestation := strings.TrimPrefix(attestationResponse.Attestation, "0x") | ||
| attestationBytes, err := hex.DecodeString(attestation) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
|
||
| return (&usdcMintInfo{ | ||
| attestation: attestationBytes, | ||
| message: msg, | ||
| }).serialize(), nil | ||
| } | ||
|
|
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| // mintToken mints the USDC on the destination chain using the mint info. | ||
| func (b *usdcBridge) mintToken(txOpts *bind.TransactOpts, mintInfoB []byte) (*types.Transaction, error) { | ||
| mintInfo, err := deserializeUsdcMintInfo(mintInfoB) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
|
||
| return b.messasgeTransmitter.ReceiveMessage(txOpts, mintInfo.message, mintInfo.attestation) | ||
| } |
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