CCIP2.ETH

Off-Chain ENS Records Resolver

Contracts

Install Foundry

curl -L https://foundry.paradigm.xyz | bash && source ~/.bashrc && foundryup

Install dependency

forge install foundry-rs/forge-std --no-commit --no-git

Goerli Testnet

./test/goerli.sh

Specification

a) CCIP-Read Resolver (EIP2544/EIP3688)

This specification is an extension of ENSIP-10 (EIP-2544/EIP-3688) using IPNS for off-chain records storage.

function resolve(bytes calldata name, bytes calldata data) external view returns(bytes memory result)

where, the _path to query an ENS record and the full _domain as string shall be decoded from encoded name variable using DNSDecode() function:

function DNSDecode(
    bytes calldata name
) public view returns (
    string memory _domain, string memory _path, string memory _label
){
    uint level = 1; // domain heirarchy level
    uint i = 1; // counter
    uint len uint8(bytes1(name[:1])); // length of label
    _label = string(name[1: i += len]); // final value is TLD ".eth"
    _path = _label; // suffix after /.well-known/
    _domain = _label; // full domain as string

    while(name[i] > 0x0) { // DNS Decode
        len = uint8(bytes1(name[i: ++i]));
        _label = string(name[i: i += len]);
        _domain = string.concat(_domain, ".", _label);
        _path = string.concat(_label, "/", _path);
        ++level;
    }
}

b) Off-chain Records Storage Format

For this specification to make practical sense, we expect the contenhash to be of IPNS type, other storage pointers work out of box too. IPNS hashes are key-based decentralized storage pointers that only need to be added once to on-chain storage by the user. IPNS hashes can in turn serve as proxy and point to upgradeable IPFS or IPLD content. In the parent IPNS directory, the records must be stored in the RFC-8615 compliant .well-known directory format. ENS records for any name sub.domain.eth must then be stored in JSON format under a reverse-DNS style directory path using / instead of . as separator, i.e. in format ipfs://<hash>/.well-known/eth/domain/sub/<record>.json.

1. Some Examples:

• ENS text record for vitalik.eth's avatar is stored at ipns://<ipns_hash>/.well-known/eth/vitalik/avatar.json formatted as

{ data: abi.encode(string("eip155:1/erc1155:0xb32979486938aa9694bfc898f35dbed459f44424/10063")) }

• ETH address record for sub.domain.eth is stored at https://sub.domain.eth/.well-known/eth/domain/sub/addr-60.json formatted as

{ data: abi.encode(<addr-60>) }

Note: If the JSON data is signed by the Registrant of domain.eth, it must be prefixed with bytes4 of callback function selector as,

{ data: bytes.concat(Resolver.___callback.selector, <signed_data>}

2. Resolver function → JSON file names:

Type	Function	JSON file
Text Records (ENSIP-05)	text(bytes32 node, string memory key)	<key>.json
Ethereum Address	addr(bytes32 node)	addr-60.json
Multichain Address (ENSIP-09)	addr(bytes32 node, uint coinType)	addr-<coinType>.json
Public Key	pubkey(bytes32 node)	pubkey.json
Contenthash (ENSIP-07)	contenthash(bytes32 node)	contenthash.json

CCIP Gateways

Type	Identifier	Gateway URL
ipns://<contenthash>	0xe5	https://<base36-CID-v1>.ipns.dweb.link/.well-known/..
ipfs://<contenthash>	0xe3	https://<base32-CID-v1>.ipfs.dweb.link/.well-known/..
ENS + IPNS Node		https://domain-eth.ipns.dweb.link/.well-known/..
ENS		https://domain.eth.limo/.well-known/..
ENS + IPFS2 resolver	0xe3, 0xe5	https://<CID-v1>.ipfs2.eth.limo/.well-known/..

Code

--

	//...

	funMap[iResolver.addr.selector] = "addr-60"; // eth address
	funMap[iResolver.pubkey.selector] = "pubkey";
	funMap[iResolver.name.selector] = "name";

	//...

	bytes4 fun = bytes4(data[: 4]); // 4 bytes identifier

	if (fun == iResolver.contenthash.selector) {
		if (level == 3) resolveContenthash(labels[0]);
		__lookup(HomeContenthash);
	}

	string memory jsonFile;
	if (fun == iResolver.text.selector) {
		jsonFile = abi.decode(data[36: ], (string));
	} else if (fun == iOverloadResolver.addr.selector) {
		jsonFile = string.concat(
			"addr-",
			uintToNumString(abi.decode(data[36: ], (uint)))
		);
	} else {
		jsonFile = funMap[fun];
		require(bytes(jsonFile).length != 0, "Invalid Resolver Function");
	}

--

	function resolve(bytes calldata name, bytes calldata data) external view returns(bytes memory) {
        uint level;
        uint len;
        bytes[] memory labels = new bytes[](3);
        //string memory _path;
        // dns decode
        for (uint i; name[i] > 0x0;) {
            len = uint8(bytes1(name[i: ++i]));
            labels[level] = name[i: i += len];
            //_path = string.concat(string(labels[level]), "/", _path);
            ++level;
        }
        bytes4 fun = bytes4(data[: 4]); // 4 bytes identifier
        if (fun == iResolver.contenthash.selector) {
            if (level == 3)
                resolveContenthash(labels[0]);

            __lookup(HomeContenthash);
        }
        string memory jsonFile;
        if (fun == iResolver.text.selector) {
            jsonFile = abi.decode(data[36: ], (string));
        } else if (fun == iOverloadResolver.addr.selector) {
            jsonFile = string.concat(
                "addr-",
                uintToNumString(abi.decode(data[36: ], (uint)))
            );
        } else {
            jsonFile = funMap[fun];
            require(bytes(jsonFile).length != 0, "Invalid Resolver Function");
        }

        string memory _prefix;
        if (level == 3) {
            _prefix = string.concat(
                "https://",
                string(labels[0]),
                ".",
                string(labels[1]),
                ".eth"
            );
        } else {
            _prefix = string.concat("https://", string(labels[0]), ".eth");
        }
        revert OffchainLookup(
            address(this), // callback contract
            listGate(_prefix, jsonFile), // gateway URL array
            "", // {data} field, blank//recheck
            IPFS2.__callback.selector, // callback function
            abi.encode( // extradata
                block.number, // checkpoint
                keccak256(data), // namehash + calldata
                keccak256(
                    abi.encodePacked(
                        blockhash(block.number - 1),
                        address(this),
                        msg.sender,
                        keccak256(data)
                    )
                )
            )
        );
    }