package smart_contract import ( "github.com/nspcc-dev/neo-go/pkg/interop/binary" "github.com/nspcc-dev/neo-go/pkg/interop/blockchain" "github.com/nspcc-dev/neo-go/pkg/interop/crypto" "github.com/nspcc-dev/neo-go/pkg/interop/engine" "github.com/nspcc-dev/neo-go/pkg/interop/runtime" "github.com/nspcc-dev/neo-go/pkg/interop/storage" "github.com/nspcc-dev/neo-go/pkg/interop/util" ) type ( ballot struct { id []byte // id of the voting decision n [][]byte // already voted inner ring nodes block int // block with the last vote } node struct { pub []byte } cheque struct { id []byte } ) const ( tokenHash = "\x3b\x7d\x37\x11\xc6\xf0\xcc\xf9\xb1\xdc\xa9\x03\xd1\xbf\xa1\xd8\x96\xf1\x23\x8c" innerRingCandidateFee = 100 * 1000 * 1000 // 10^8 version = 2 voteKey = "ballots" blockDiff = 20 // change base on performance evaluation ) func Main(op string, args []interface{}) interface{} { // The trigger determines whether this smart-contract is being // run in 'verification' or 'application' mode. if runtime.GetTrigger() != runtime.Application() { return false } /* Utility operations - they will be changed in production: - Deploy(params: address, pubKey, ... ) - setup initial inner ring state User operations: - InnerRingList() - get list of inner ring nodes addresses and public keys - InnerRingCandidateRemove(params: pubKey) - remove node with given public key from the inner ring candidate queue - InnerRingCandidateAdd(params: pubKey) - add node to the inner ring candidate queue - Deposit(params: pubKey, amount) - deposit GAS to the NeoFS account - Withdraw(params: withdrawCheque) - withdraw GAS from the NeoFS account - InnerRingUpdate(params: irCheque) - change list of inner ring nodes - IsInnerRing(params: pubKey) - returns true if pubKey presented in inner ring list - Version() - get version of the NeoFS smart-contract Params: - address - string of the valid multiaddress (github.com/multiformats/multiaddr) - pubKey - 33 byte public key - withdrawCheque - serialized structure, that confirms GAS transfer; contains inner ring signatures - irCheque - serialized structure, that confirms new inner ring node list; contains inner ring signatures */ ctx := storage.GetContext() switch op { case "Deploy": irList := getSerialized(ctx, "InnerRingList").([]node) if len(irList) >= 3 { panic("contract already deployed") } irList = []node{} for i := 0; i < len(args); i++ { pub := args[i].([]byte) irList = append(irList, node{pub: pub}) } data := binary.Serialize(irList) storage.Put(ctx, "InnerRingList", data) data = binary.Serialize([]interface{}{}) storage.Put(ctx, "UsedVerifCheckList", data) storage.Put(ctx, "InnerRingCandidates", data) data = binary.Serialize([]ballot{}) storage.Put(ctx, voteKey, data) return true case "InnerRingList": irList := getSerialized(ctx, "InnerRingList").([]node) return irList case "InnerRingCandidateRemove": data := args[0].([]byte) // public key if !runtime.CheckWitness(data) { panic("you should be the owner of the public key") } delSerializedIR(ctx, "InnerRingCandidates", data) return true case "InnerRingCandidateAdd": key := args[0].([]byte) // public key if !runtime.CheckWitness(key) { panic("you should be the owner of the public key") } candidates := getSerialized(ctx, "InnerRingCandidates").([]node) if containsPub(candidates, key) { panic("is already in list") } from := pubToScriptHash(key) to := runtime.GetExecutingScriptHash() params := []interface{}{from, to, innerRingCandidateFee} transferred := engine.AppCall([]byte(tokenHash), "transfer", params).(bool) if !transferred { panic("failed to transfer funds, aborting") } candidate := node{pub: key} if !putSerialized(ctx, "InnerRingCandidates", candidate) { panic("failed to put candidate into the queue") } return true case "Deposit": if len(args) < 2 || len(args) > 3 { panic("deposit: bad arguments") } from := args[0].([]byte) if !runtime.CheckWitness(from) { panic("deposit: you should be the owner of the wallet") } amount := args[1].(int) if amount > 0 { amount = amount * 100000000 } to := runtime.GetExecutingScriptHash() params := []interface{}{from, to, amount} transferred := engine.AppCall([]byte(tokenHash), "transfer", params).(bool) if !transferred { panic("deposit: failed to transfer funds, aborting") } runtime.Log("deposit: funds have been transferred") var rcv = from if len(args) == 3 { rcv = args[2].([]byte) // todo: check if rcv value is valid } tx := runtime.GetScriptContainer() runtime.Notify("Deposit", from, amount, rcv, tx.Hash) return true case "Withdraw": if len(args) != 2 { panic("withdraw: bad arguments") } user := args[0].([]byte) if !runtime.CheckWitness(user) { panic("withdraw: you should be the owner of the wallet") } amount := args[1].(int) if amount > 0 { amount = amount * 100000000 } tx := runtime.GetScriptContainer() runtime.Notify("Withdraw", user, amount, tx.Hash) return true case "Cheque": if len(args) != 4 { panic("cheque: bad arguments") } id := args[0].([]byte) // unique cheque id user := args[1].([]byte) // GAS receiver amount := args[2].(int) // amount of GAS lockAcc := args[3].([]byte) // lock account from internal banking that must be cashed out ctx := storage.GetContext() hashID := crypto.SHA256(id) irList := getSerialized(ctx, "InnerRingList").([]node) usedList := getSerialized(ctx, "UsedVerifCheckList").([]cheque) threshold := len(irList)/3*2 + 1 irKey := innerRingInvoker(irList) if len(irKey) == 0 { panic("cheque: invoked by non inner ring node") } c := cheque{id: id} // todo: use different cheque id for inner ring update and withdraw if containsCheck(usedList, c) { panic("cheque: non unique id") } n := vote(ctx, hashID, irKey) if n >= threshold { removeVotes(ctx, hashID) from := runtime.GetExecutingScriptHash() params := []interface{}{from, user, amount} transferred := engine.AppCall([]byte(tokenHash), "transfer", params).(bool) if !transferred { panic("cheque: failed to transfer funds, aborting") } putSerialized(ctx, "UsedVerifCheckList", c) runtime.Notify("Cheque", id, user, amount, lockAcc) } return true case "InnerRingUpdate": data := args[0].([]byte) id := data[:8] var ln interface{} = data[8:10] listItemCount := ln.(int) listSize := listItemCount * 33 offset := 8 + 2 + listSize irList := getSerialized(ctx, "InnerRingList").([]node) usedList := getSerialized(ctx, "UsedVerifCheckList").([]cheque) threshold := len(irList)/3*2 + 1 irKey := innerRingInvoker(irList) if len(irKey) == 0 { panic("innerRingUpdate: invoked by non inner ring node") } c := cheque{id: id} if containsCheck(usedList, c) { panic("innerRingUpdate: cheque has non unique id") } chequeHash := crypto.SHA256(data) n := vote(ctx, chequeHash, irKey) if n >= threshold { removeVotes(ctx, chequeHash) candidates := getSerialized(ctx, "InnerRingCandidates").([]node) offset = 10 newIR := []node{} loop: for i := 0; i < listItemCount; i, offset = i+1, offset+33 { pub := data[offset : offset+33] for j := 0; j < len(irList); j++ { n := irList[j] if util.Equals(n.pub, pub) { newIR = append(newIR, n) continue loop } } for j := 0; j < len(candidates); j++ { n := candidates[j] if util.Equals(n.pub, pub) { newIR = append(newIR, n) continue loop } } } if len(newIR) != listItemCount { panic("new inner ring wasn't processed correctly") } for i := 0; i < len(newIR); i++ { n := newIR[i] delSerializedIR(ctx, "InnerRingCandidates", n.pub) } newIRData := binary.Serialize(newIR) storage.Put(ctx, "InnerRingList", newIRData) putSerialized(ctx, "UsedVerifCheckList", c) runtime.Notify("InnerRingUpdate", c.id, newIRData) } return true case "IsInnerRing": if len(args) != 1 { panic("isInnerRing: wrong arguments") } key := args[0].([]byte) if len(key) != 33 { panic("isInnerRing: incorrect public key") } irList := getSerialized(ctx, "InnerRingList").([]node) for i := range irList { node := irList[i] if util.Equals(node.pub, key) { return true } } return false case "Version": return version } panic("unknown operation") } // fixme: use strict type deserialization wrappers func getSerialized(ctx storage.Context, key string) interface{} { data := storage.Get(ctx, key).([]byte) if len(data) != 0 { return binary.Deserialize(data) } return nil } func delSerialized(ctx storage.Context, key string, value []byte) bool { data := storage.Get(ctx, key).([]byte) deleted := false var newList [][]byte if len(data) != 0 { lst := binary.Deserialize(data).([][]byte) for i := 0; i < len(lst); i++ { if util.Equals(value, lst[i]) { deleted = true } else { newList = append(newList, lst[i]) } } if deleted { if len(newList) != 0 { data := binary.Serialize(newList) storage.Put(ctx, key, data) } else { storage.Delete(ctx, key) } runtime.Log("target element has been removed") return true } } runtime.Log("target element has not been removed") return false } func putSerialized(ctx storage.Context, key string, value interface{}) bool { data := storage.Get(ctx, key).([]byte) var lst []interface{} if len(data) != 0 { lst = binary.Deserialize(data).([]interface{}) } lst = append(lst, value) data = binary.Serialize(lst) storage.Put(ctx, key, data) return true } func pubToScriptHash(pkey []byte) []byte { // pre := []byte{0x21} // buf := append(pre, pkey...) // buf = append(buf, 0xac) // h := crypto.Hash160(buf) // // return h // fixme: someday ripemd syscall will appear // or simply store script-hashes along with public key return []byte{0x0F, 0xED} } func containsCheck(lst []cheque, c cheque) bool { for i := 0; i < len(lst); i++ { if util.Equals(c, lst[i]) { return true } } return false } func containsPub(lst []node, elem []byte) bool { for i := 0; i < len(lst); i++ { e := lst[i] if util.Equals(elem, e.pub) { return true } } return false } func delSerializedIR(ctx storage.Context, key string, value []byte) bool { data := storage.Get(ctx, key).([]byte) deleted := false newList := []node{} if len(data) != 0 { lst := binary.Deserialize(data).([]node) for i := 0; i < len(lst); i++ { n := lst[i] if util.Equals(value, n.pub) { deleted = true } else { newList = append(newList, n) } } if deleted { data := binary.Serialize(newList) storage.Put(ctx, key, data) runtime.Log("target element has been removed") return true } } runtime.Log("target element has not been removed") return false } // innerRingInvoker returns public key of inner ring node that invoked contract. func innerRingInvoker(ir []node) []byte { for i := 0; i < len(ir); i++ { node := ir[i] if runtime.CheckWitness(node.pub) { return node.pub } } return nil } func vote(ctx storage.Context, id, from []byte) int { var ( newCandidates []ballot candidates = getBallots(ctx) found = -1 blockHeight = blockchain.GetHeight() ) for i := 0; i < len(candidates); i++ { cnd := candidates[i] if bytesEqual(cnd.id, id) { voters := cnd.n for j := range voters { if bytesEqual(voters[j], from) { return len(voters) } } voters = append(voters, from) cnd = ballot{id: id, n: voters, block: blockHeight} found = len(voters) } // do not add old ballots, they are invalid if blockHeight-cnd.block <= blockDiff { newCandidates = append(newCandidates, cnd) } } if found < 0 { found = 1 voters := [][]byte{from} newCandidates = append(newCandidates, ballot{ id: id, n: voters, block: blockHeight}) } setSerialized(ctx, voteKey, newCandidates) return found } func removeVotes(ctx storage.Context, id []byte) { var ( newCandidates []ballot candidates = getBallots(ctx) ) for i := 0; i < len(candidates); i++ { cnd := candidates[i] if !bytesEqual(cnd.id, id) { newCandidates = append(newCandidates, cnd) } } setSerialized(ctx, voteKey, newCandidates) } // setSerialized serializes data and puts it into contract storage. func setSerialized(ctx storage.Context, key interface{}, value interface{}) { data := binary.Serialize(value) storage.Put(ctx, key, data) } // getInnerRingNodes returns deserialized slice of vote ballots. func getBallots(ctx storage.Context) []ballot { data := storage.Get(ctx, voteKey) if data != nil { return binary.Deserialize(data.([]byte)).([]ballot) } return []ballot{} } // bytesEqual compares two slice of bytes by wrapping them into strings, // which is necessary with new util.Equal interop behaviour, see neo-go#1176. func bytesEqual(a []byte, b []byte) bool { return util.Equals(string(a), string(b)) }