Add commit phase to consensus algorithm (#534)

* Add commit phase to consensus algorithm

* fix tests

* Prevent repeated sending of `Commit` messages

* RPC call gettransactionheight (#541)

* getrawtransactionheight

Nowadays two calls are need to get a transaction height, `getrawtransaction` with `verbose` and then use the `blockhash`.
Other option is to use `confirmations`, but it can be misleading.

* Minnor fix

* Shargon's tip

* modified

* Allow to use the wallet inside a RPC plugin (#536)

* Clean code

* Clean code

neo.UnitTests/UT_Consensus.cs

@@ -99,8 +99,7 @@ public void ConsensusService_Primary_Sends_PrepareRequest_After_OnStart()
                 Nonce = mockConsensusContext.Object.Nonce,
                 NextConsensus = mockConsensusContext.Object.NextConsensus,
                 TransactionHashes = new UInt256[0],
-                MinerTransaction = minerTx, //(MinerTransaction)Transactions[TransactionHashes[0]],
-                Signature = new byte[64]//Signatures[MyIndex]
+                MinerTransaction = minerTx //(MinerTransaction)Transactions[TransactionHashes[0]],
             };
 
             ConsensusMessage mprep = prep;

neo/Consensus/Commit.cs

@@ -0,0 +1,25 @@
+using System.IO;
+
+namespace Neo.Consensus
+{
+    internal class Commit : ConsensusMessage
+    {
+        public byte[] Signature;
+
+        public override int Size => base.Size + Signature.Length;
+
+        public Commit() : base(ConsensusMessageType.Commit) { }
+
+        public override void Deserialize(BinaryReader reader)
+        {
+            base.Deserialize(reader);
+            Signature = reader.ReadBytes(64);
+        }
+
+        public override void Serialize(BinaryWriter writer)
+        {
+            base.Serialize(writer);
+            writer.Write(Signature);
+        }
+    }
+}

neo/Consensus/ConsensusContext.cs

@@ -28,7 +28,8 @@ internal class ConsensusContext : IConsensusContext
         public UInt160 NextConsensus { get; set; }
         public UInt256[] TransactionHashes { get; set; }
         public Dictionary<UInt256, Transaction> Transactions { get; set; }
-        public byte[][] Signatures { get; set; }
+        public bool[] Preparations { get; set; }
+        public byte[][] Commits { get; set; }
         public byte[] ExpectedView { get; set; }
         private Snapshot snapshot;
         private KeyPair keyPair;
@@ -46,14 +47,12 @@ public ConsensusContext(Wallet wallet)
 
         public void ChangeView(byte view_number)
         {
-            State &= ConsensusState.SignatureSent;
+            State = ConsensusState.Initial;
             ViewNumber = view_number;
             PrimaryIndex = GetPrimaryIndex(view_number);
-            if (State == ConsensusState.Initial)
-            {
-                TransactionHashes = null;
-                Signatures = new byte[Validators.Length][];
-            }
+            TransactionHashes = null;
+            Preparations = new bool[Validators.Length];
+            Commits = new byte[Validators.Length][];
             if (MyIndex >= 0)
                 ExpectedView[MyIndex] = view_number;
             _header = null;
@@ -66,9 +65,9 @@ public Block CreateBlock()
             Contract contract = Contract.CreateMultiSigContract(M, Validators);
             ContractParametersContext sc = new ContractParametersContext(block);
             for (int i = 0, j = 0; i < Validators.Length && j < M; i++)
-                if (Signatures[i] != null)
+                if (Commits[i] != null)
                 {
-                    sc.AddSignature(contract, Validators[i], Signatures[i]);
+                    sc.AddSignature(contract, Validators[i], Commits[i]);
                     j++;
                 }
             sc.Verifiable.Witnesses = sc.GetWitnesses();
@@ -95,6 +94,16 @@ public ConsensusPayload MakeChangeView()
             });
         }
 
+        public ConsensusPayload MakeCommit()
+        {
+            if (Commits[MyIndex] == null)
+                Commits[MyIndex] = MakeHeader()?.Sign(keyPair);
+            return MakeSignedPayload(new Commit
+            {
+                Signature = Commits[MyIndex]
+            });
+        }
+
         private Block _header = null;
         public Block MakeHeader()
         {
@@ -132,11 +141,6 @@ private ConsensusPayload MakeSignedPayload(ConsensusMessage message)
             return payload;
         }
 
-        public void SignHeader()
-        {
-            Signatures[MyIndex] = MakeHeader()?.Sign(keyPair);
-        }
-
         private void SignPayload(ConsensusPayload payload)
         {
             ContractParametersContext sc;
@@ -159,17 +163,13 @@ public ConsensusPayload MakePrepareRequest()
                 Nonce = Nonce,
                 NextConsensus = NextConsensus,
                 TransactionHashes = TransactionHashes,
-                MinerTransaction = (MinerTransaction)Transactions[TransactionHashes[0]],
-                Signature = Signatures[MyIndex]
+                MinerTransaction = (MinerTransaction)Transactions[TransactionHashes[0]]
             });
         }
 
-        public ConsensusPayload MakePrepareResponse(byte[] signature)
+        public ConsensusPayload MakePrepareResponse()
         {
-            return MakeSignedPayload(new PrepareResponse
-            {
-                Signature = signature
-            });
+            return MakeSignedPayload(new PrepareResponse());
         }
 
         public void Reset()
@@ -184,7 +184,8 @@ public void Reset()
             MyIndex = -1;
             PrimaryIndex = BlockIndex % (uint)Validators.Length;
             TransactionHashes = null;
-            Signatures = new byte[Validators.Length][];
+            Preparations = new bool[Validators.Length];
+            Commits = new byte[Validators.Length][];
             ExpectedView = new byte[Validators.Length];
             keyPair = null;
             for (int i = 0; i < Validators.Length; i++)

neo/Consensus/ConsensusMessageType.cs

@@ -10,5 +10,7 @@ internal enum ConsensusMessageType : byte
         PrepareRequest = 0x20,
         [ReflectionCache(typeof(PrepareResponse))]
         PrepareResponse = 0x21,
+        [ReflectionCache(typeof(Commit))]
+        Commit = 0x30,
     }
 }

neo/Consensus/ConsensusService.cs

@@ -59,10 +59,10 @@ private bool AddTransaction(Transaction tx, bool verify)
                 if (context.VerifyRequest())
                 {
                     Log($"send prepare response");
-                    context.State |= ConsensusState.SignatureSent;
-                    context.SignHeader();
-                    localNode.Tell(new LocalNode.SendDirectly { Inventory = context.MakePrepareResponse(context.Signatures[context.MyIndex]) });
-                    CheckSignatures();
+                    context.State |= ConsensusState.ResponseSent;
+                    context.Preparations[context.MyIndex] = true;
+                    localNode.Tell(new LocalNode.SendDirectly { Inventory = context.MakePrepareResponse() });
+                    CheckPreparations();
                 }
                 else
                 {
@@ -83,6 +83,17 @@ private void ChangeTimer(TimeSpan delay)
             }, ActorRefs.NoSender);
         }
 
+        private void CheckCommits()
+        {
+            if (context.Commits.Count(p => p != null) >= context.M && context.TransactionHashes.All(p => context.Transactions.ContainsKey(p)))
+            {
+                Block block = context.CreateBlock();
+                Log($"relay block: {block.Hash}");
+                localNode.Tell(new LocalNode.Relay { Inventory = block });
+                context.State |= ConsensusState.BlockSent;
+            }
+        }
+
         private void CheckExpectedView(byte view_number)
         {
             if (context.ViewNumber == view_number) return;
@@ -92,14 +103,15 @@ private void CheckExpectedView(byte view_number)
             }
         }
 
-        private void CheckSignatures()
+        private void CheckPreparations()
         {
-            if (context.Signatures.Count(p => p != null) >= context.M && context.TransactionHashes.All(p => context.Transactions.ContainsKey(p)))
+            if (context.Preparations.Count(p => p) >= context.M && context.TransactionHashes.All(p => context.Transactions.ContainsKey(p)))
             {
-                Block block = context.CreateBlock();
-                Log($"relay block: {block.Hash}");
-                localNode.Tell(new LocalNode.Relay { Inventory = block });
-                context.State |= ConsensusState.BlockSent;
+                ConsensusPayload payload = context.MakeCommit();
+                Log($"send commit");
+                localNode.Tell(new LocalNode.SendDirectly { Inventory = payload });
+                context.State |= ConsensusState.CommitSent;
+                CheckCommits();
             }
         }
 
@@ -136,13 +148,31 @@ private void Log(string message, LogLevel level = LogLevel.Info)
 
         private void OnChangeViewReceived(ConsensusPayload payload, ChangeView message)
         {
+            if (context.State.HasFlag(ConsensusState.CommitSent))
+                return;
             if (message.NewViewNumber <= context.ExpectedView[payload.ValidatorIndex])
                 return;
             Log($"{nameof(OnChangeViewReceived)}: height={payload.BlockIndex} view={message.ViewNumber} index={payload.ValidatorIndex} nv={message.NewViewNumber}");
             context.ExpectedView[payload.ValidatorIndex] = message.NewViewNumber;
             CheckExpectedView(message.NewViewNumber);
         }
 
+        private void OnCommitReceived(ConsensusPayload payload, Commit commit)
+        {
+            if (context.Commits[payload.ValidatorIndex] != null) return;
+            Log($"{nameof(OnCommitReceived)}: height={payload.BlockIndex} view={commit.ViewNumber} index={payload.ValidatorIndex}");
+            byte[] hashData = context.MakeHeader()?.GetHashData();
+            if (hashData == null)
+            {
+                context.Commits[payload.ValidatorIndex] = commit.Signature;
+            }
+            else if (Crypto.Default.VerifySignature(hashData, commit.Signature, context.Validators[payload.ValidatorIndex].EncodePoint(false)))
+            {
+                context.Commits[payload.ValidatorIndex] = commit.Signature;
+                CheckCommits();
+            }
+        }
+
         private void OnConsensusPayload(ConsensusPayload payload)
         {
             if (context.State.HasFlag(ConsensusState.BlockSent)) return;
@@ -169,16 +199,19 @@ private void OnConsensusPayload(ConsensusPayload payload)
             }
             if (message.ViewNumber != context.ViewNumber && message.Type != ConsensusMessageType.ChangeView)
                 return;
-            switch (message.Type)
+            switch (message)
             {
-                case ConsensusMessageType.ChangeView:
-                    OnChangeViewReceived(payload, (ChangeView)message);
+                case ChangeView view:
+                    OnChangeViewReceived(payload, view);
                     break;
-                case ConsensusMessageType.PrepareRequest:
-                    OnPrepareRequestReceived(payload, (PrepareRequest)message);
+                case PrepareRequest request:
+                    OnPrepareRequestReceived(payload, request);
                     break;
-                case ConsensusMessageType.PrepareResponse:
-                    OnPrepareResponseReceived(payload, (PrepareResponse)message);
+                case PrepareResponse response:
+                    OnPrepareResponseReceived(payload, response);
+                    break;
+                case Commit commit:
+                    OnCommitReceived(payload, commit);
                     break;
             }
         }
@@ -212,13 +245,12 @@ private void OnPrepareRequestReceived(ConsensusPayload payload, PrepareRequest m
             context.NextConsensus = message.NextConsensus;
             context.TransactionHashes = message.TransactionHashes;
             context.Transactions = new Dictionary<UInt256, Transaction>();
+            context.Preparations[payload.ValidatorIndex] = true;
             byte[] hashData = context.MakeHeader().GetHashData();
-            if (!Crypto.Default.VerifySignature(hashData, message.Signature, context.Validators[payload.ValidatorIndex].EncodePoint(false))) return;
-            for (int i = 0; i < context.Signatures.Length; i++)
-                if (context.Signatures[i] != null)
-                    if (!Crypto.Default.VerifySignature(hashData, context.Signatures[i], context.Validators[i].EncodePoint(false)))
-                        context.Signatures[i] = null;
-            context.Signatures[payload.ValidatorIndex] = message.Signature;
+            for (int i = 0; i < context.Commits.Length; i++)
+                if (context.Commits[i] != null)
+                    if (!Crypto.Default.VerifySignature(hashData, context.Commits[i], context.Validators[i].EncodePoint(false)))
+                        context.Commits[i] = null;
             Dictionary<UInt256, Transaction> mempool = Blockchain.Singleton.GetMemoryPool().ToDictionary(p => p.Hash);
             List<Transaction> unverified = new List<Transaction>();
             foreach (UInt256 hash in context.TransactionHashes.Skip(1))
@@ -251,18 +283,12 @@ private void OnPrepareRequestReceived(ConsensusPayload payload, PrepareRequest m
 
         private void OnPrepareResponseReceived(ConsensusPayload payload, PrepareResponse message)
         {
-            if (context.Signatures[payload.ValidatorIndex] != null) return;
+            if (context.Preparations[payload.ValidatorIndex]) return;
             Log($"{nameof(OnPrepareResponseReceived)}: height={payload.BlockIndex} view={message.ViewNumber} index={payload.ValidatorIndex}");
-            byte[] hashData = context.MakeHeader()?.GetHashData();
-            if (hashData == null)
-            {
-                context.Signatures[payload.ValidatorIndex] = message.Signature;
-            }
-            else if (Crypto.Default.VerifySignature(hashData, message.Signature, context.Validators[payload.ValidatorIndex].EncodePoint(false)))
-            {
-                context.Signatures[payload.ValidatorIndex] = message.Signature;
-                CheckSignatures();
-            }
+            if (context.State.HasFlag(ConsensusState.CommitSent)) return;
+            context.Preparations[payload.ValidatorIndex] = true;
+            if (context.State.HasFlag(ConsensusState.RequestSent) || context.State.HasFlag(ConsensusState.RequestReceived))
+                CheckPreparations();
         }
 
         protected override void OnReceive(object message)
@@ -304,13 +330,10 @@ private void OnTimer(Timer timer)
             if (context.State.HasFlag(ConsensusState.Primary) && !context.State.HasFlag(ConsensusState.RequestSent))
             {
                 Log($"send prepare request: height={timer.Height} view={timer.ViewNumber}");
-                context.State |= ConsensusState.RequestSent;
-                if (!context.State.HasFlag(ConsensusState.SignatureSent))
-                {
-                    context.Fill();
-                    context.SignHeader();
-                }
+                context.Fill();
                 localNode.Tell(new LocalNode.SendDirectly { Inventory = context.MakePrepareRequest() });
+                context.State |= ConsensusState.RequestSent;
+                context.Preparations[context.MyIndex] = true;
                 if (context.TransactionHashes.Length > 1)
                 {
                     foreach (InvPayload payload in InvPayload.CreateGroup(InventoryType.TX, context.TransactionHashes.Skip(1).ToArray()))
@@ -320,14 +343,15 @@ private void OnTimer(Timer timer)
             }
             else if ((context.State.HasFlag(ConsensusState.Primary) && context.State.HasFlag(ConsensusState.RequestSent)) || context.State.HasFlag(ConsensusState.Backup))
             {
-                RequestChangeView();
+                if (!context.State.HasFlag(ConsensusState.CommitSent))
+                    RequestChangeView();
             }
         }
 
         private void OnTransaction(Transaction transaction)
         {
             if (transaction.Type == TransactionType.MinerTransaction) return;
-            if (!context.State.HasFlag(ConsensusState.Backup) || !context.State.HasFlag(ConsensusState.RequestReceived) || context.State.HasFlag(ConsensusState.SignatureSent) || context.State.HasFlag(ConsensusState.ViewChanging) || context.State.HasFlag(ConsensusState.BlockSent))
+            if (!context.State.HasFlag(ConsensusState.Backup) || !context.State.HasFlag(ConsensusState.RequestReceived) || context.State.HasFlag(ConsensusState.ResponseSent) || context.State.HasFlag(ConsensusState.ViewChanging) || context.State.HasFlag(ConsensusState.BlockSent))
                 return;
             if (context.Transactions.ContainsKey(transaction.Hash)) return;
             if (!context.TransactionHashes.Contains(transaction.Hash)) return;

neo/Consensus/ConsensusState.cs

@@ -10,8 +10,9 @@ public enum ConsensusState : byte
         Backup = 0x02,
         RequestSent = 0x04,
         RequestReceived = 0x08,
-        SignatureSent = 0x10,
-        BlockSent = 0x20,
-        ViewChanging = 0x40,
+        ResponseSent = 0x10,
+        CommitSent = 0x20,
+        BlockSent = 0x40,
+        ViewChanging = 0x80,
     }
 }

neo/Consensus/IConsensusContext.cs

@@ -20,7 +20,8 @@ public interface IConsensusContext : IDisposable
         UInt160 NextConsensus { get; set; }
         UInt256[] TransactionHashes { get; set; }
         Dictionary<UInt256, Transaction> Transactions { get; set; }
-        byte[][] Signatures { get; set; }
+        bool[] Preparations { get; set; }
+        byte[][] Commits { get; set; }
         byte[] ExpectedView { get; set; }
 
         int M { get; }
@@ -40,13 +41,13 @@ public interface IConsensusContext : IDisposable
 
         ConsensusPayload MakeChangeView();
 
-        Block MakeHeader();
+        ConsensusPayload MakeCommit();
 
-        void SignHeader();
+        Block MakeHeader();
 
         ConsensusPayload MakePrepareRequest();
 
-        ConsensusPayload MakePrepareResponse(byte[] signature);
+        ConsensusPayload MakePrepareResponse();
 
         void Reset();