package registrar
import (
"encoding/binary"
"fmt"
"math/big"
"regexp"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
)
/*
Registrar implements the Ethereum name registrar services mapping
- arbitrary strings to ethereum addresses
- hashes to hashes
- hashes to arbitrary strings
(likely will provide lookup service for all three)
The Registrar is used by
* the roundtripper transport implementation of
url schemes to resolve domain names and services that register these names
* contract info retrieval (NatSpec).
The Registrar uses 3 contracts on the blockchain:
* GlobalRegistrar: Name (string) -> Address (Owner)
* HashReg : Key Hash (hash of domain name or contract code) -> Content Hash
* UrlHint : Content Hash -> Url Hint
These contracts are (currently) not included in the genesis block.
Each Set<X> needs to be called once on each blockchain/network once.
Contract addresses need to be set (HashReg and UrlHint retrieved from the global
registrar the first time any Registrar method is called in a client session
So the caller needs to make sure the relevant environment initialised the desired
contracts
*/
var (
UrlHintAddr = "0x0"
HashRegAddr = "0x0"
GlobalRegistrarAddr = "0x0"
// GlobalRegistrarAddr = "0xc6d9d2cd449a754c494264e1809c50e34d64562b"
zero = regexp.MustCompile("^(0x)?0*$")
)
const (
trueHex = "0000000000000000000000000000000000000000000000000000000000000001"
falseHex = "0000000000000000000000000000000000000000000000000000000000000000"
)
func abiSignature(s string) string {
return common.ToHex(crypto.Sha3([]byte(s))[:4])
}
var (
HashRegName = "HashReg"
UrlHintName = "UrlHint"
registerContentHashAbi = abiSignature("register(uint256,uint256)")
registerUrlAbi = abiSignature("register(uint256,uint8,uint256)")
setOwnerAbi = abiSignature("setowner()")
reserveAbi = abiSignature("reserve(bytes32)")
resolveAbi = abiSignature("addr(bytes32)")
registerAbi = abiSignature("setAddress(bytes32,address,bool)")
addressAbiPrefix = falseHex[:24]
)
// Registrar's backend is defined as an interface (implemented by xeth, but could be remote)
type Backend interface {
StorageAt(string, string) string
Transact(fromStr, toStr, nonceStr, valueStr, gasStr, gasPriceStr, codeStr string) (string, error)
Call(fromStr, toStr, valueStr, gasStr, gasPriceStr, codeStr string) (string, string, error)
}
// TODO Registrar should also just implement The Resolver and Registry interfaces
// Simplify for now.
type VersionedRegistrar interface {
Resolver(*big.Int) *Registrar
Registry() *Registrar
}
type Registrar struct {
backend Backend
}
func New(b Backend) (res *Registrar) {
res = &Registrar{b}
return
}
func (self *Registrar) SetGlobalRegistrar(namereg string, addr common.Address) (txhash string, err error) {
if namereg != "" {
GlobalRegistrarAddr = namereg
return
}
if GlobalRegistrarAddr == "0x0" || GlobalRegistrarAddr == "0x" {
if (addr == common.Address{}) {
err = fmt.Errorf("GlobalRegistrar address not found and sender for creation not given")
return
} else {
txhash, err = self.backend.Transact(addr.Hex(), "", "", "", "800000", "", GlobalRegistrarCode)
if err != nil {
err = fmt.Errorf("GlobalRegistrar address not found and sender for creation failed: %v", err)
return
}
}
}
return
}
func (self *Registrar) SetHashReg(hashreg string, addr common.Address) (txhash string, err error) {
if hashreg != "" {
HashRegAddr = hashreg
} else {
if !zero.MatchString(HashRegAddr) {
return
}
nameHex, extra := encodeName(HashRegName, 2)
hashRegAbi := resolveAbi + nameHex + extra
glog.V(logger.Detail).Infof("\ncall HashRegAddr %v with %v\n", GlobalRegistrarAddr, hashRegAbi)
var res string
res, _, err = self.backend.Call("", GlobalRegistrarAddr, "", "", "", hashRegAbi)
if len(res) >= 40 {
HashRegAddr = "0x" + res[len(res)-40:len(res)]
}
if err != nil || zero.MatchString(HashRegAddr) {
if (addr == common.Address{}) {
err = fmt.Errorf("HashReg address not found and sender for creation not given")
return
}
txhash, err = self.backend.Transact(addr.Hex(), "", "", "", "", "", HashRegCode)
if err != nil {
err = fmt.Errorf("HashReg address not found and sender for creation failed: %v", err)
}
glog.V(logger.Detail).Infof("created HashRegAddr @ txhash %v\n", txhash)
} else {
glog.V(logger.Detail).Infof("HashRegAddr found at @ %v\n", HashRegAddr)
return
}
}
return
}
func (self *Registrar) SetUrlHint(urlhint string, addr common.Address) (txhash string, err error) {
if urlhint != "" {
UrlHintAddr = urlhint
} else {
if !zero.MatchString(UrlHintAddr) {
return
}
nameHex, extra := encodeName(UrlHintName, 2)
urlHintAbi := resolveAbi + nameHex + extra
glog.V(logger.Detail).Infof("UrlHint address query data: %s to %s", urlHintAbi, GlobalRegistrarAddr)
var res string
res, _, err = self.backend.Call("", GlobalRegistrarAddr, "", "", "", urlHintAbi)
if len(res) >= 40 {
UrlHintAddr = "0x" + res[len(res)-40:len(res)]
}
if err != nil || zero.MatchString(UrlHintAddr) {
if (addr == common.Address{}) {
err = fmt.Errorf("UrlHint address not found and sender for creation not given")
return
}
txhash, err = self.backend.Transact(addr.Hex(), "", "", "", "210000", "", UrlHintCode)
if err != nil {
err = fmt.Errorf("UrlHint address not found and sender for creation failed: %v", err)
}
glog.V(logger.Detail).Infof("created UrlHint @ txhash %v\n", txhash)
} else {
glog.V(logger.Detail).Infof("UrlHint found @ %v\n", HashRegAddr)
return
}
}
return
}
// ReserveName(from, name) reserves name for the sender address in the globalRegistrar
// the tx needs to be mined to take effect
func (self *Registrar) ReserveName(address common.Address, name string) (txh string, err error) {
nameHex, extra := encodeName(name, 2)
abi := reserveAbi + nameHex + extra
glog.V(logger.Detail).Infof("Reserve data: %s", abi)
return self.backend.Transact(
address.Hex(),
GlobalRegistrarAddr,
"", "", "", "",
abi,
)
}
// SetAddressToName(from, name, addr) will set the Address to address for name
// in the globalRegistrar using from as the sender of the transaction
// the tx needs to be mined to take effect
func (self *Registrar) SetAddressToName(from common.Address, name string, address common.Address) (txh string, err error) {
nameHex, extra := encodeName(name, 6)
addrHex := encodeAddress(address)
abi := registerAbi + nameHex + addrHex + trueHex + extra
glog.V(logger.Detail).Infof("SetAddressToName data: %s to %s ", abi, GlobalRegistrarAddr)
return self.backend.Transact(
from.Hex(),
GlobalRegistrarAddr,
"", "", "", "",
abi,
)
}
// NameToAddr(from, name) queries the registrar for the address on name
func (self *Registrar) NameToAddr(from common.Address, name string) (address common.Address, err error) {
nameHex, extra := encodeName(name, 2)
abi := resolveAbi + nameHex + extra
glog.V(logger.Detail).Infof("NameToAddr data: %s", abi)
res, _, err := self.backend.Call(
from.Hex(),
GlobalRegistrarAddr,
"", "", "",
abi,
)
if err != nil {
return
}
address = common.HexToAddress(res)
return
}
// called as first step in the registration process on HashReg
func (self *Registrar) SetOwner(address common.Address) (txh string, err error) {
return self.backend.Transact(
address.Hex(),
HashRegAddr,
"", "", "", "",
setOwnerAbi,
)
}
// registers some content hash to a key/code hash
// e.g., the contract Info combined Json Doc's ContentHash
// to CodeHash of a contract or hash of a domain
func (self *Registrar) SetHashToHash(address common.Address, codehash, dochash common.Hash) (txh string, err error) {
_, err = self.SetOwner(address)
if err != nil {
return
}
codehex := common.Bytes2Hex(codehash[:])
dochex := common.Bytes2Hex(dochash[:])
data := registerContentHashAbi + codehex + dochex
glog.V(logger.Detail).Infof("SetHashToHash data: %s sent to %v\n", data, HashRegAddr)
return self.backend.Transact(
address.Hex(),
HashRegAddr,
"", "", "", "",
data,
)
}
// SetUrlToHash(from, hash, url) registers a url to a content hash so that the content can be fetched
// address is used as sender for the transaction and will be the owner of a new
// registry entry on first time use
// FIXME: silently doing nothing if sender is not the owner
// note that with content addressed storage, this step is no longer necessary
func (self *Registrar) SetUrlToHash(address common.Address, hash common.Hash, url string) (txh string, err error) {
hashHex := common.Bytes2Hex(hash[:])
var urlHex string
urlb := []byte(url)
var cnt byte
n := len(urlb)
for n > 0 {
if n > 32 {
n = 32
}
urlHex = common.Bytes2Hex(urlb[:n])
urlb = urlb[n:]
n = len(urlb)
bcnt := make([]byte, 32)
bcnt[31] = cnt
data := registerUrlAbi +
hashHex +
common.Bytes2Hex(bcnt) +
common.Bytes2Hex(common.Hex2BytesFixed(urlHex, 32))
txh, err = self.backend.Transact(
address.Hex(),
UrlHintAddr,
"", "", "", "",
data,
)
if err != nil {
return
}
cnt++
}
return
}
// HashToHash(key) resolves contenthash for key (a hash) using HashReg
// resolution is costless non-transactional
// implemented as direct retrieval from db
func (self *Registrar) HashToHash(khash common.Hash) (chash common.Hash, err error) {
// look up in hashReg
at := HashRegAddr[2:]
key := storageAddress(storageMapping(storageIdx2Addr(1), khash[:]))
hash := self.backend.StorageAt(at, key)
if hash == "0x0" || len(hash) < 3 || (hash == common.Hash{}.Hex()) {
err = fmt.Errorf("content hash not found for '%v'", khash.Hex())
return
}
copy(chash[:], common.Hex2BytesFixed(hash[2:], 32))
return
}
// HashToUrl(contenthash) resolves the url for contenthash using UrlHint
// resolution is costless non-transactional
// implemented as direct retrieval from db
// if we use content addressed storage, this step is no longer necessary
func (self *Registrar) HashToUrl(chash common.Hash) (uri string, err error) {
// look up in URL reg
var str string = " "
var idx uint32
for len(str) > 0 {
mapaddr := storageMapping(storageIdx2Addr(1), chash[:])
key := storageAddress(storageFixedArray(mapaddr, storageIdx2Addr(idx)))
hex := self.backend.StorageAt(UrlHintAddr[2:], key)
str = string(common.Hex2Bytes(hex[2:]))
l := 0
for (l < len(str)) && (str[l] == 0) {
l++
}
str = str[l:]
uri = uri + str
idx++
}
if len(uri) == 0 {
err = fmt.Errorf("GetURLhint: URL hint not found for '%v'", chash.Hex())
}
return
}
func storageIdx2Addr(varidx uint32) []byte {
data := make([]byte, 32)
binary.BigEndian.PutUint32(data[28:32], varidx)
return data
}
func storageMapping(addr, key []byte) []byte {
data := make([]byte, 64)
copy(data[0:32], key[0:32])
copy(data[32:64], addr[0:32])
sha := crypto.Sha3(data)
return sha
}
func storageFixedArray(addr, idx []byte) []byte {
var carry byte
for i := 31; i >= 0; i-- {
var b byte = addr[i] + idx[i] + carry
if b < addr[i] {
carry = 1
} else {
carry = 0
}
addr[i] = b
}
return addr
}
func storageAddress(addr []byte) string {
return common.ToHex(addr)
}
func encodeAddress(address common.Address) string {
return addressAbiPrefix + address.Hex()[2:]
}
func encodeName(name string, index uint8) (string, string) {
extra := common.Bytes2Hex([]byte(name))
if len(name) > 32 {
return fmt.Sprintf("%064x", index), extra
}
return extra + falseHex[len(extra):], ""
}
