Revert the revert hanging block, and fix the issues

WalletWasabi/Extensions/NBitcoinExtensions.cs

@@ -5,6 +5,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading;
 using System.Threading.Tasks;
 using WalletWasabi.Helpers;
 using WalletWasabi.Models;
@@ -15,6 +16,38 @@ namespace NBitcoin
 {
 	public static class NBitcoinExtensions
 	{
+		public static async Task<Block> DownloadBlockAsync(this Node node, uint256 hash, CancellationToken cancellationToken)
+		{
+			if (node.State == NodeState.Connected)
+				node.VersionHandshake(cancellationToken);
+			using (var listener = node.CreateListener())
+			{
+				var getdata = new GetDataPayload(new InventoryVector(node.AddSupportedOptions(InventoryType.MSG_BLOCK), hash));
+				await node.SendMessageAsync(getdata);
+				cancellationToken.ThrowIfCancellationRequested();
+
+				// Bitcoin Core processes the messages sequentially and does not send a NOTFOUND message if the remote node is pruned and the data not available.
+				// A good way to get any feedback about whether the node knows the block or not is to send a ping request.
+				// If block is not known by the remote node, the pong will be sent immediately, else it will be sent after the block download.
+				ulong pingNonce = RandomUtils.GetUInt64();
+				await node.SendMessageAsync(new PingPayload() { Nonce = pingNonce });
+				while (true)
+				{
+					cancellationToken.ThrowIfCancellationRequested();
+					var message = listener.ReceiveMessage(cancellationToken);
+					if (message.Message.Payload is NotFoundPayload ||
+						(message.Message.Payload is PongPayload p && p.Nonce == pingNonce))
+					{
+						throw new InvalidOperationException($"Disconnected local node, because it does not have the block data.");
+					}
+					else if (message.Message.Payload is BlockPayload b && b.Object?.GetHash() == hash)
+					{
+						return b.Object;
+					}
+				}
+			}
+		}
+
 		public static TxoRef ToTxoRef(this OutPoint me) => new TxoRef(me);
 
 		public static IEnumerable<TxoRef> ToTxoRefs(this TxInList me)

WalletWasabi/Services/WalletService.cs

@@ -806,16 +806,12 @@ public async Task<Block> GetOrDownloadBlockAsync(uint256 hash, CancellationToken
 
 							Block blockFromLocalNode = null;
 							// Should timeout faster. Not sure if it should ever fail though. Maybe let's keep like this later for remote node connection.
-							using (var cts = new CancellationTokenSource(TimeSpan.FromSeconds(64))) // 1/2 ADSL	512 kbit/s	00:00:32
+							using (var cts = new CancellationTokenSource(TimeSpan.FromSeconds(64)))
 							{
-								blockFromLocalNode = LocalBitcoinCoreNode.GetBlocks(new uint256[] { hash }, cts.Token)?.Single();
+								blockFromLocalNode = await LocalBitcoinCoreNode.DownloadBlockAsync(hash, cts.Token);
 							}
 
-							if (blockFromLocalNode is null)
-							{
-								throw new InvalidOperationException($"Disconnected local node, because couldn't parse received block.");
-							}
-							else if (!blockFromLocalNode.Check())
+							if (!blockFromLocalNode.Check())
 							{
 								throw new InvalidOperationException($"Disconnected node, because block invalid block received!");
 							}
@@ -863,14 +859,7 @@ public async Task<Block> GetOrDownloadBlockAsync(uint256 hash, CancellationToken
 						{
 							using (var cts = new CancellationTokenSource(TimeSpan.FromSeconds(RuntimeParams.Instance.NetworkNodeTimeout))) // 1/2 ADSL	512 kbit/s	00:00:32
 							{
-								block = node.GetBlocks(new uint256[] { hash }, cts.Token)?.Single();
-							}
-
-							if (block is null)
-							{
-								Logger.LogInfo<WalletService>($"Disconnected node: {node.RemoteSocketAddress}, because couldn't parse received block.");
-								node.DisconnectAsync("Couldn't parse block.");
-								continue;
+								block = await node.DownloadBlockAsync(hash, cts.Token);
 							}
 
 							if (!block.Check())
@@ -1580,7 +1569,9 @@ private void SerializeTransactionCache()
 				Encoding.UTF8);
 		}
 
-		// Current timeout used when downloading a block from the remote node. It is defined in seconds.
+		/// <summary>
+		/// Current timeout used when downloading a block from the remote node. It is defined in seconds.
+		/// </summary>
 		private async Task NodeTimeoutsAsync(bool increaseDecrease)
 		{
 			if (increaseDecrease)