Add MaxBlockSystemFee (#1689)

* add max block system fee

* fix tx

* fix and add more ut

* format

* optimze code

* Reset maxblocksystem = 9000/GAS

* Update src/neo/SmartContract/Native/PolicyContract.cs

Co-authored-by: HaoqiangZhang <gripzhang@outlook.com>

* Remove new line in log

* Update ConsensusService.cs

* up Prefix_MaxBlockSize as skiptable.insert

Co-authored-by: Shargon <shargon@gmail.com>
Co-authored-by: HaoqiangZhang <gripzhang@outlook.com>

src/neo/Consensus/ConsensusContext.cs

@@ -219,6 +219,14 @@ internal int GetExpectedBlockSize()
                 Transactions.Values.Sum(u => u.Size);   // Sum Txs
         }
 
+        /// <summary>
+        /// Return the expected block system fee
+        /// </summary>
+        internal long GetExpectedBlockSystemFee()
+        {
+            return Transactions.Values.Sum(u => u.SystemFee);  // Sum Txs
+        }
+
         /// <summary>
         /// Return the expected block size without txs
         /// </summary>
@@ -248,9 +256,10 @@ internal int GetExpectedBlockSizeWithoutTransactions(int expectedTransactions)
         /// Prevent that block exceed the max size
         /// </summary>
         /// <param name="txs">Ordered transactions</param>
-        internal void EnsureMaxBlockSize(IEnumerable<Transaction> txs)
+        internal void EnsureMaxBlockLimitation(IEnumerable<Transaction> txs)
         {
             uint maxBlockSize = NativeContract.Policy.GetMaxBlockSize(Snapshot);
+            long maxBlockSystemFee = NativeContract.Policy.GetMaxBlockSystemFee(Snapshot);
             uint maxTransactionsPerBlock = NativeContract.Policy.GetMaxTransactionsPerBlock(Snapshot);
 
             // Limit Speaker proposal to the limit `MaxTransactionsPerBlock` or all available transactions of the mempool
@@ -261,14 +270,19 @@ internal void EnsureMaxBlockSize(IEnumerable<Transaction> txs)
 
             // Expected block size
             var blockSize = GetExpectedBlockSizeWithoutTransactions(txs.Count());
+            var blockSystemFee = 0L;
 
-            // Iterate transaction until reach the size
+            // Iterate transaction until reach the size or maximum system fee
             foreach (Transaction tx in txs)
             {
                 // Check if maximum block size has been already exceeded with the current selected set
                 blockSize += tx.Size;
                 if (blockSize > maxBlockSize) break;
 
+                // Check if maximum block system fee has been already exceeded with the current selected set
+                blockSystemFee += tx.SystemFee;
+                if (blockSystemFee > maxBlockSystemFee) break;
+
                 hashes.Add(tx.Hash);
                 Transactions.Add(tx.Hash, tx);
                 SendersFeeMonitor.AddSenderFee(tx);
@@ -283,7 +297,7 @@ public ConsensusPayload MakePrepareRequest()
             Span<byte> buffer = stackalloc byte[sizeof(ulong)];
             random.NextBytes(buffer);
             Block.ConsensusData.Nonce = BitConverter.ToUInt64(buffer);
-            EnsureMaxBlockSize(Blockchain.Singleton.MemPool.GetSortedVerifiedTransactions());
+            EnsureMaxBlockLimitation(Blockchain.Singleton.MemPool.GetSortedVerifiedTransactions());
             Block.Timestamp = Math.Max(TimeProvider.Current.UtcNow.ToTimestampMS(), PrevHeader.Timestamp + 1);
 
             return PreparationPayloads[MyIndex] = MakeSignedPayload(new PrepareRequest

src/neo/Consensus/ConsensusService.cs

@@ -92,7 +92,14 @@ private bool CheckPrepareResponse()
                 // Check maximum block size via Native Contract policy
                 if (context.GetExpectedBlockSize() > NativeContract.Policy.GetMaxBlockSize(context.Snapshot))
                 {
-                    Log($"rejected block: {context.Block.Index}{Environment.NewLine} The size exceed the policy", LogLevel.Warning);
+                    Log($"rejected block: {context.Block.Index} The size exceed the policy", LogLevel.Warning);
+                    RequestChangeView(ChangeViewReason.BlockRejectedByPolicy);
+                    return false;
+                }
+                // Check maximum block system fee via Native Contract policy
+                if (context.GetExpectedBlockSystemFee() > NativeContract.Policy.GetMaxBlockSystemFee(context.Snapshot))
+                {
+                    Log($"rejected block: {context.Block.Index} The system fee exceed the policy", LogLevel.Warning);
                     RequestChangeView(ChangeViewReason.BlockRejectedByPolicy);
                     return false;
                 }

src/neo/Network/P2P/Payloads/Transaction.cs

@@ -268,6 +268,8 @@ public virtual VerifyResult VerifyForEachBlock(StoreView snapshot, BigInteger to
             UInt160[] hashes = GetScriptHashesForVerifying(snapshot);
             if (NativeContract.Policy.GetBlockedAccounts(snapshot).Intersect(hashes).Any())
                 return VerifyResult.PolicyFail;
+            if (NativeContract.Policy.GetMaxBlockSystemFee(snapshot) < SystemFee)
+                return VerifyResult.PolicyFail;
             BigInteger balance = NativeContract.GAS.BalanceOf(snapshot, Sender);
             BigInteger fee = SystemFee + NetworkFee + totalSenderFeeFromPool;
             if (balance < fee) return VerifyResult.InsufficientFunds;

src/neo/SmartContract/Native/PolicyContract.cs

@@ -19,7 +19,8 @@ public sealed class PolicyContract : NativeContract
         private const byte Prefix_MaxTransactionsPerBlock = 23;
         private const byte Prefix_FeePerByte = 10;
         private const byte Prefix_BlockedAccounts = 15;
-        private const byte Prefix_MaxBlockSize = 16;
+        private const byte Prefix_MaxBlockSize = 12;
+        private const byte Prefix_MaxBlockSystemFee = 17;
 
         public PolicyContract()
         {
@@ -50,6 +51,10 @@ internal override void Initialize(ApplicationEngine engine)
             {
                 Value = BitConverter.GetBytes(512u)
             });
+            engine.Snapshot.Storages.Add(CreateStorageKey(Prefix_MaxBlockSystemFee), new StorageItem
+            {
+                Value = BitConverter.GetBytes(9000 * (long)GAS.Factor) // For the transfer method of NEP5, the maximum persisting time is about three seconds.
+            });
             engine.Snapshot.Storages.Add(CreateStorageKey(Prefix_FeePerByte), new StorageItem
             {
                 Value = BitConverter.GetBytes(1000L)
@@ -72,6 +77,12 @@ public uint GetMaxBlockSize(StoreView snapshot)
             return BitConverter.ToUInt32(snapshot.Storages[CreateStorageKey(Prefix_MaxBlockSize)].Value, 0);
         }
 
+        [ContractMethod(0_01000000, CallFlags.AllowStates)]
+        public long GetMaxBlockSystemFee(StoreView snapshot)
+        {
+            return BitConverter.ToInt64(snapshot.Storages[CreateStorageKey(Prefix_MaxBlockSystemFee)].Value, 0);
+        }
+
         [ContractMethod(0_01000000, CallFlags.AllowStates)]
         public long GetFeePerByte(StoreView snapshot)
         {
@@ -103,6 +114,16 @@ private bool SetMaxTransactionsPerBlock(ApplicationEngine engine, uint value)
             return true;
         }
 
+        [ContractMethod(0_03000000, CallFlags.AllowModifyStates)]
+        private bool SetMaxBlockSystemFee(ApplicationEngine engine, long value)
+        {
+            if (!CheckCommittees(engine)) return false;
+            if (value <= 4007600) return false;
+            StorageItem storage = engine.Snapshot.Storages.GetAndChange(CreateStorageKey(Prefix_MaxBlockSystemFee));
+            storage.Value = BitConverter.GetBytes(value);
+            return true;
+        }
+
         [ContractMethod(0_03000000, CallFlags.AllowModifyStates)]
         private bool SetFeePerByte(ApplicationEngine engine, long value)
         {

tests/neo.UnitTests/Consensus/UT_ConsensusContext.cs

@@ -6,6 +6,7 @@
 using Neo.Ledger;
 using Neo.Network.P2P.Payloads;
 using Neo.SmartContract.Native;
+using Neo.VM.Types;
 using Neo.Wallets;
 using System;
 using System.Linq;
@@ -58,7 +59,7 @@ public void TestMaxBlockSize_Good()
             // Only one tx, is included
 
             var tx1 = CreateTransactionWithSize(200);
-            _context.EnsureMaxBlockSize(new Transaction[] { tx1 });
+            _context.EnsureMaxBlockLimitation(new Transaction[] { tx1 });
             EnsureContext(_context, tx1);
 
             // All txs included
@@ -68,7 +69,7 @@ public void TestMaxBlockSize_Good()
 
             for (int x = 0; x < max; x++) txs[x] = CreateTransactionWithSize(100);
 
-            _context.EnsureMaxBlockSize(txs);
+            _context.EnsureMaxBlockLimitation(txs);
             EnsureContext(_context, txs);
         }
 
@@ -79,7 +80,7 @@ public void TestMaxBlockSize_Exceed()
 
             var tx1 = CreateTransactionWithSize(200);
             var tx2 = CreateTransactionWithSize(256 * 1024);
-            _context.EnsureMaxBlockSize(new Transaction[] { tx1, tx2 });
+            _context.EnsureMaxBlockLimitation(new Transaction[] { tx1, tx2 });
             EnsureContext(_context, tx1);
 
             // Exceed txs number, just MaxTransactionsPerBlock included
@@ -89,16 +90,41 @@ public void TestMaxBlockSize_Exceed()
 
             for (int x = 0; x < max; x++) txs[x] = CreateTransactionWithSize(100);
 
-            _context.EnsureMaxBlockSize(txs);
+            _context.EnsureMaxBlockLimitation(txs);
             EnsureContext(_context, txs.Take(max).ToArray());
         }
 
+        [TestMethod]
+        public void TestMaxBlockSytemFee()
+        {
+            var tx1 = CreateTransactionWithSytemFee(NativeContract.Policy.GetMaxBlockSystemFee(_context.Snapshot) / 2);
+
+            // Less than MaxBlockSystemFee
+            _context.EnsureMaxBlockLimitation(new Transaction[] { tx1 });
+            EnsureContext(_context, new Transaction[] { tx1 });
+
+            // Equal MaxBlockSystemFee
+            tx1 = CreateTransactionWithSytemFee(NativeContract.Policy.GetMaxBlockSystemFee(_context.Snapshot) / 2 + 1);
+            var tx2 = CreateTransactionWithSytemFee(NativeContract.Policy.GetMaxBlockSystemFee(_context.Snapshot) / 2 - 1);
+
+            _context.EnsureMaxBlockLimitation(new Transaction[] { tx1, tx2 });
+            EnsureContext(_context, new Transaction[] { tx1, tx2 });
+
+            // Exceed MaxBlockSystemFee
+            tx1 = CreateTransactionWithSytemFee(NativeContract.Policy.GetMaxBlockSystemFee(_context.Snapshot) / 2 + 3);
+            tx2 = CreateTransactionWithSytemFee(NativeContract.Policy.GetMaxBlockSystemFee(_context.Snapshot) / 2 - 3);
+            var tx3 = CreateTransactionWithSytemFee(NativeContract.Policy.GetMaxBlockSystemFee(_context.Snapshot) / 2 - 4);
+
+            _context.EnsureMaxBlockLimitation(new Transaction[] { tx1, tx2, tx3 });
+            EnsureContext(_context, new Transaction[] { tx1, tx2 });
+        }
+
         private Transaction CreateTransactionWithSize(int v)
         {
             var r = new Random();
             var tx = new Transaction()
             {
-                Attributes = Array.Empty<TransactionAttribute>(),
+                Attributes = System.Array.Empty<TransactionAttribute>(),
                 NetworkFee = 0,
                 Nonce = (uint)Environment.TickCount,
                 Script = new byte[0],
@@ -114,6 +140,23 @@ private Transaction CreateTransactionWithSize(int v)
             return tx;
         }
 
+        private Transaction CreateTransactionWithSytemFee(long fee)
+        {
+            var tx = new Transaction()
+            {
+                Attributes = System.Array.Empty<TransactionAttribute>(),
+                NetworkFee = 0,
+                Nonce = (uint)Environment.TickCount,
+                Script = new byte[0],
+                Sender = UInt160.Zero,
+                SystemFee = fee,
+                ValidUntilBlock = int.MaxValue,
+                Version = 0,
+                Witnesses = new Witness[0],
+            };
+            return tx;
+        }
+
         private Block SignBlock(ConsensusContext context)
         {
             context.Block.MerkleRoot = null;

tests/neo.UnitTests/SmartContract/Native/UT_PolicyContract.cs

@@ -5,6 +5,7 @@
 using Neo.Network.P2P.Payloads;
 using Neo.SmartContract;
 using Neo.SmartContract.Native;
+using Neo.SmartContract.Native.Tokens;
 using Neo.UnitTests.Extensions;
 using Neo.VM;
 using System.Linq;
@@ -31,7 +32,7 @@ public void Check_Initialize()
 
             NativeContract.Policy.Initialize(new ApplicationEngine(TriggerType.Application, null, snapshot, 0));
 
-            (keyCount + 4).Should().Be(snapshot.Storages.GetChangeSet().Count());
+            (keyCount + 5).Should().Be(snapshot.Storages.GetChangeSet().Count());
 
             var ret = NativeContract.Policy.Call(snapshot, "getMaxTransactionsPerBlock");
             ret.Should().BeOfType<VM.Types.Integer>();
@@ -41,6 +42,10 @@ public void Check_Initialize()
             ret.Should().BeOfType<VM.Types.Integer>();
             ret.GetBigInteger().Should().Be(1024 * 256);
 
+            ret = NativeContract.Policy.Call(snapshot, "getMaxBlockSystemFee");
+            ret.Should().BeOfType<VM.Types.Integer>();
+            ret.GetBigInteger().Should().Be(9000 * 100000000L);
+
             ret = NativeContract.Policy.Call(snapshot, "getFeePerByte");
             ret.Should().BeOfType<VM.Types.Integer>();
             ret.GetBigInteger().Should().Be(1000);
@@ -98,6 +103,54 @@ public void Check_SetMaxBlockSize()
             ret.GetBigInteger().Should().Be(1024);
         }
 
+        [TestMethod]
+        public void Check_SetMaxBlockSystemFee()
+        {
+            var snapshot = Blockchain.Singleton.GetSnapshot();
+
+            // Fake blockchain
+
+            snapshot.PersistingBlock = new Block() { Index = 1000, PrevHash = UInt256.Zero };
+            snapshot.Blocks.Add(UInt256.Zero, new Neo.Ledger.TrimmedBlock() { NextConsensus = UInt160.Zero });
+
+            UInt160 committeeMultiSigAddr = NativeContract.NEO.GetCommitteeAddress(snapshot);
+
+            NativeContract.Policy.Initialize(new ApplicationEngine(TriggerType.Application, null, snapshot, 0));
+
+            // Without signature
+
+            var ret = NativeContract.Policy.Call(snapshot, new Nep5NativeContractExtensions.ManualWitness(null),
+                "setMaxBlockSystemFee", new ContractParameter(ContractParameterType.Integer) { Value = 1024 * (long)NativeContract.GAS.Factor });
+            ret.Should().BeOfType<VM.Types.Boolean>();
+            ret.ToBoolean().Should().BeFalse();
+
+            ret = NativeContract.Policy.Call(snapshot, "getMaxBlockSystemFee");
+            ret.Should().BeOfType<VM.Types.Integer>();
+            ret.GetBigInteger().Should().Be(9000 * (long)NativeContract.GAS.Factor);
+
+            // Less than expected
+
+            ret = NativeContract.Policy.Call(snapshot, new Nep5NativeContractExtensions.ManualWitness(committeeMultiSigAddr),
+                 "setMaxBlockSystemFee", new ContractParameter(ContractParameterType.Integer) { Value = -1000 });
+            ret.Should().BeOfType<VM.Types.Boolean>();
+            ret.ToBoolean().Should().BeFalse();
+
+            ret = NativeContract.Policy.Call(snapshot, "getMaxBlockSystemFee");
+            ret.Should().BeOfType<VM.Types.Integer>();
+            ret.GetBigInteger().Should().Be(9000 * (long)NativeContract.GAS.Factor);
+
+            // With signature
+
+            ret = NativeContract.Policy.Call(snapshot, new Nep5NativeContractExtensions.ManualWitness(committeeMultiSigAddr),
+                "setMaxBlockSystemFee", new ContractParameter(ContractParameterType.Integer) { Value = 1024 * (long)NativeContract.GAS.Factor });
+            ret.Should().BeOfType<VM.Types.Boolean>();
+            ret.ToBoolean().Should().BeTrue();
+
+            ret = NativeContract.Policy.Call(snapshot, "getMaxBlockSystemFee");
+            ret.Should().BeOfType<VM.Types.Integer>();
+            ret.GetBigInteger().Should().Be(1024 * (long)NativeContract.GAS.Factor);
+        }
+
         [TestMethod]
         public void Check_SetMaxTransactionsPerBlock()
         {