More proper way of reading byte arrays, improved handling of incorrec…

…t magic bytes. Fixed testnet magic.

README.md

@@ -51,6 +51,12 @@ while (true) {
 ### Example: Transactions
 Listen for transactions sent to the network: [TransactionLoggerExample.java](/examples/TransactionLoggerExample.java).
 
+### Testnet
+If you want to connect to a testnet node instead, you need to provide the magic bytes for that like this:
+```java
+ErgoSocket ergoSocket = new ErgoSocket(address, self, ErgoSocket.TESTNET_MAGIC);
+```
+
 ## Notes
 
 Please understand that ergonnection is only a networking library.

src/main/java/com/satergo/ergonnection/ErgoSocket.java

@@ -6,19 +6,17 @@
 import com.satergo.ergonnection.records.Peer;
 import org.bouncycastle.jcajce.provider.digest.Blake2b;
 
-import java.io.ByteArrayOutputStream;
-import java.io.DataInputStream;
-import java.io.DataOutputStream;
-import java.io.IOException;
+import java.io.*;
 import java.net.InetSocketAddress;
 import java.net.Socket;
+import java.net.SocketException;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
 public class ErgoSocket extends Socket {
 
-	public static final byte[] MAINNET_MAGIC = { 1, 0, 2, 4 }, TESTNET_MAGIC = { 2, 0, 0, 1 };
+	public static final byte[] MAINNET_MAGIC = { 1, 0, 2, 4 }, TESTNET_MAGIC = { 2, 0, 2, 3 };
 
 	/**
 	 * A basic feature set specifying that the state is "utxo", the client is verifying transactions, has no PoPoW suffix, and 1 block is stored.
@@ -34,10 +32,10 @@ public class ErgoSocket extends Socket {
 	private final DataInputStream in;
 
 	/**
-	 * Creates a new socket for the mainnet
+	 * Creates a new socket
 	 *
 	 * @param address      Address to connect to
-	 * @param self         A Peer object that represent this client itself (this is the data that will be sent to the target peer)
+	 * @param self         A Peer object that represents this client itself (this is the data that will be sent to the target peer)
 	 * @param networkMagic The magic bytes of this network, see {@link #MAINNET_MAGIC} and {@link #TESTNET_MAGIC}
 	 * @throws IOException socket exception
 	 */
@@ -52,7 +50,7 @@ public ErgoSocket(InetSocketAddress address, Peer self, byte[] networkMagic) thr
 	 * Creates a new socket for the mainnet
 	 *
 	 * @param address   Address to connect to
-	 * @param self      A Peer object that represent this client itself (this is the data that will be sent to the target peer)
+	 * @param self      A Peer object that represents this client itself (this is the data that will be sent to the target peer)
 	 * @throws IOException socket exception
 	 */
 	public ErgoSocket(InetSocketAddress address, Peer self) throws IOException {
@@ -90,15 +88,27 @@ public void send(ProtocolMessage message) throws IOException {
 		}
 	}
 
+	/**
+	 * @throws SocketException if the socket is closed, or it was closed while the message was being read
+	 */
 	public ProtocolMessage acceptMessage() throws IOException {
-		byte[] magic = in.readNBytes(4);
-		if (!Arrays.equals(networkMagic, magic))
-			throw new IllegalArgumentException("incorrect magic " + Arrays.toString(magic) + " (must be " + Arrays.toString(networkMagic) + ")");
-		int code = in.readUnsignedByte();
-		int length = in.readInt();
-		in.skipNBytes(4); // checksum
-		byte[] bytes = in.readNBytes(length);
-		return Protocol.deserializeMessage(code, bytes);
+		try {
+			byte[] magic = InternalStreamUtils.readNFully(in, 4);
+			if (!Arrays.equals(networkMagic, magic)) {
+				close();
+				throw new IllegalArgumentException("Incorrect magic " + Arrays.toString(magic) + " received (must be " + Arrays.toString(networkMagic) + ")");
+			}
+			int code = in.readUnsignedByte();
+			int length = in.readInt();
+			in.skipNBytes(4); // checksum
+			byte[] bytes = InternalStreamUtils.readNFully(in, length);
+			return Protocol.deserializeMessage(code, bytes);
+		} catch (EOFException e) {
+			// Receiving this exception is due to the socket being closed, but it will not have
+			// been marked as such so this method is called
+			close();
+			throw new SocketException("Socket is closed");
+		}
 	}
 
 	public void sendHandshake() throws IOException {

src/main/java/com/satergo/ergonnection/InternalStreamUtils.java

@@ -0,0 +1,31 @@
+package com.satergo.ergonnection;
+
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+
+public class InternalStreamUtils {
+	private InternalStreamUtils() {}
+
+	public static void writeUTF8ByteLen(VLQOutputStream out, String s) throws IOException {
+		if (s.length() > 255) throw new IllegalArgumentException("too long");
+		byte[] bytes = s.getBytes(StandardCharsets.UTF_8);
+		out.write(bytes.length);
+		out.write(bytes);
+	}
+
+	public static String readUTF8ByteLen(VLQInputStream in) throws IOException {
+		int len = in.read();
+		byte[] bytes = in.readNFully(len);
+		return new String(bytes, StandardCharsets.UTF_8);
+	}
+
+	/**
+	 * @throws java.io.EOFException if this input stream reaches the end before reading all the bytes.
+	 */
+	public static byte[] readNFully(DataInputStream in, int length) throws IOException {
+		byte[] bytes = new byte[length];
+		in.readFully(bytes);
+		return bytes;
+	}
+}

src/main/java/com/satergo/ergonnection/VLQInputStream.java

@@ -33,6 +33,12 @@ public void readFully(byte[] b, int off, int len) throws IOException {
 		}
 	}
 
+	public byte[] readNFully(int length) throws IOException {
+		byte[] bytes = new byte[length];
+		readFully(bytes);
+		return bytes;
+	}
+
 	public int skipBytes(int n) throws IOException {
 		int total = 0;
 		int cur;

src/main/java/com/satergo/ergonnection/messages/Inv.java

@@ -18,7 +18,7 @@ public static Inv deserialize(VLQInputStream in) throws IOException {
 		int count = (int) in.readUnsignedInt();
 		ArrayList<byte[]> elements = new ArrayList<>();
 		for (int i = 0; i < count; i++) {
-			elements.add(in.readNBytes(32));
+			elements.add(in.readNFully(32));
 		}
 		return new Inv(typeId, Collections.unmodifiableList(elements));
 	}

src/main/java/com/satergo/ergonnection/messages/ModifierRequest.java

@@ -18,7 +18,7 @@ public static ModifierRequest deserialize(VLQInputStream in) throws IOException
 		int count = (int) in.readUnsignedInt();
 		ArrayList<byte[]> elements = new ArrayList<>();
 		for (int i = 0; i < count; i++) {
-			elements.add(in.readNBytes(32));
+			elements.add(in.readNFully(32));
 		}
 		return new ModifierRequest(typeId, Collections.unmodifiableList(elements));
 	}

src/main/java/com/satergo/ergonnection/messages/SyncInfoOld.java

@@ -17,7 +17,7 @@ public static SyncInfoOld deserialize(VLQInputStream in) throws IOException {
 		int count = in.readUnsignedShort();
 		ArrayList<byte[]> lastHeaderIDs = new ArrayList<>();
 		for (int i = 0; i < count; i++) {
-			lastHeaderIDs.add(in.readNBytes(32));
+			lastHeaderIDs.add(in.readNFully(32));
 		}
 		return new SyncInfoOld(Collections.unmodifiableList(lastHeaderIDs));
 	}

src/main/java/com/satergo/ergonnection/modifiers/ErgoTransaction.java

@@ -48,14 +48,14 @@ public static ErgoTransaction deserialize(byte[] id, byte[] data) throws IOExcep
 		int dataInputCount = in.readUnsignedShort();
 		ArrayList<DataInput> dataInputs = new ArrayList<>();
 		for (int i = 0; i < dataInputCount; i++) {
-			dataInputs.add(new DataInput(in.readNBytes(32)));
+			dataInputs.add(new DataInput(in.readNFully(32)));
 		}
 
 		// parse distinct ids of tokens in transaction outputs
 		int tokensCount = (int) in.readUnsignedInt();
 		ArrayList<TokenId> tokens = new ArrayList<>();
 		for (int i = 0; i < tokensCount; i++) {
-			tokens.add(new TokenId(in.readNBytes(32)));
+			tokens.add(new TokenId(in.readNFully(32)));
 		}
 
 		int outputCandidatesCount = in.readUnsignedShort();

src/main/java/com/satergo/ergonnection/modifiers/Header.java

@@ -21,16 +21,16 @@ public record Header(byte[] id, byte version, byte[] parentId, byte[] adProofsRo
 	public static Header deserialize(byte[] id, byte[] data) throws IOException {
 		VLQInputStream in = new VLQInputStream(new ByteArrayInputStream(data));
 		byte version = in.readByte();
-		byte[] parentId = in.readNBytes(32);
-		byte[] adProofsRoot = in.readNBytes(32);
-		byte[] transactionsRoot = in.readNBytes(32);
-		byte[] stateRoot = in.readNBytes(33);
+		byte[] parentId = in.readNFully(32);
+		byte[] adProofsRoot = in.readNFully(32);
+		byte[] transactionsRoot = in.readNFully(32);
+		byte[] stateRoot = in.readNFully(33);
 		long timestamp = in.readUnsignedLong();
-		byte[] extensionHash = in.readNBytes(32);
-		byte[] nBitsBytes = in.readNBytes(4);
+		byte[] extensionHash = in.readNFully(32);
+		byte[] nBitsBytes = in.readNFully(4);
 		long nBits = ((nBitsBytes[0] & 0xFFL) << 24) | ((nBitsBytes[1] & 0xFFL) << 16) | ((nBitsBytes[2] & 0xFFL) << 8) | (nBitsBytes[3] & 0xFFL);
 		int height = Math.toIntExact(in.readUnsignedInt());
-		byte[] votes = in.readNBytes(3);
+		byte[] votes = in.readNFully(3);
 		if (version > INITIAL_VERSION) {
 			int newFieldsSize = in.readUnsignedByte();
 			in.skipNBytes(newFieldsSize);

src/main/java/com/satergo/ergonnection/modifiers/data/AutolykosSolution.java

@@ -16,15 +16,15 @@ public record AutolykosSolution(Platform.Ecp minerPubKey, Platform.Ecp oneTimePu
 
 	public static AutolykosSolution deserialize(VLQInputStream in, byte version) throws IOException {
 		if (version == 1) {
-			Platform.Ecp minerPublicKey = groupElemFromBytes(in.readNBytes(PUBLIC_KEY_LENGTH));
-			Platform.Ecp w = groupElemFromBytes(in.readNBytes(PUBLIC_KEY_LENGTH));
-			byte[] nonce = in.readNBytes(8);
+			Platform.Ecp minerPublicKey = groupElemFromBytes(in.readNFully(PUBLIC_KEY_LENGTH));
+			Platform.Ecp w = groupElemFromBytes(in.readNFully(PUBLIC_KEY_LENGTH));
+			byte[] nonce = in.readNFully(8);
 			int dBytesLength = in.readUnsignedByte();
-			BigInteger d = BigIntegers.fromUnsignedByteArray(in.readNBytes(dBytesLength));
+			BigInteger d = BigIntegers.fromUnsignedByteArray(in.readNFully(dBytesLength));
 			return new AutolykosSolution(minerPublicKey, w, nonce, d);
 		} else {
-			Platform.Ecp minerPublicKey = groupElemFromBytes(in.readNBytes(PUBLIC_KEY_LENGTH));
-			byte[] nonce = in.readNBytes(8);
+			Platform.Ecp minerPublicKey = groupElemFromBytes(in.readNFully(PUBLIC_KEY_LENGTH));
+			byte[] nonce = in.readNFully(8);
 			return new AutolykosSolution(minerPublicKey, CryptoConstants.dlogGroup().generator(), nonce, BigInteger.ZERO);
 		}
 	}

src/main/java/com/satergo/ergonnection/records/Feature.java

@@ -9,7 +9,7 @@
 public record Feature(int id, byte[] data) implements ProtocolRecord {
 
 	public static Feature deserialize(VLQInputStream in) throws IOException {
-		return new Feature(in.readUnsignedByte(), in.readNBytes(in.readUnsignedShort()));
+		return new Feature(in.readUnsignedByte(), in.readNFully(in.readUnsignedShort()));
 	}
 
 	@Override

src/main/java/com/satergo/ergonnection/records/Header.java

@@ -9,7 +9,7 @@
 public record Header(byte[] bytes) implements ProtocolRecord {
 
 	public static Header deserialize(VLQInputStream in) throws IOException {
-		return new Header(in.readNBytes(in.readUnsignedShort()));
+		return new Header(in.readNFully(in.readUnsignedShort()));
 	}
 
 	@Override

src/main/java/com/satergo/ergonnection/records/Peer.java

@@ -1,6 +1,6 @@
 package com.satergo.ergonnection.records;
 
-import com.satergo.ergonnection.StreamUTF8;
+import com.satergo.ergonnection.InternalStreamUtils;
 import com.satergo.ergonnection.VLQInputStream;
 import com.satergo.ergonnection.VLQOutputStream;
 import com.satergo.ergonnection.Version;
@@ -33,16 +33,16 @@ public boolean hasPublicAddress() {
 	}
 
 	public static Peer deserialize(VLQInputStream in) throws IOException {
-		String agentName = StreamUTF8.readByteLen(in);
+		String agentName = InternalStreamUtils.readUTF8ByteLen(in);
 		Version version = Version.parse(in.readByte() + "." + in.readByte() + "." + in.readByte());
-		String peerName = StreamUTF8.readByteLen(in);
+		String peerName = InternalStreamUtils.readUTF8ByteLen(in);
 		boolean hasPublicAddress = in.readBoolean();
 		InetSocketAddress publicAddress = null;
 		if (hasPublicAddress) {
 			// Protocol for some reason encodes it as length + 4
 			int publicAddressLength = in.readUnsignedByte() - 4;
 			publicAddress = new InetSocketAddress(
-					InetAddress.getByAddress(in.readNBytes(publicAddressLength)),
+					InetAddress.getByAddress(in.readNFully(publicAddressLength)),
 					// For some reason, it uses u-int instead of u-short
 					(int) in.readUnsignedInt()
 			);
@@ -57,11 +57,11 @@ public static Peer deserialize(VLQInputStream in) throws IOException {
 
 	@Override
 	public void serialize(VLQOutputStream out) throws IOException {
-		StreamUTF8.writeByteLen(out, agentName);
+		InternalStreamUtils.writeUTF8ByteLen(out, agentName);
 		out.write(version().major());
 		out.write(version().minor());
 		out.write(version().patch());
-		StreamUTF8.writeByteLen(out, peerName);
+		InternalStreamUtils.writeUTF8ByteLen(out, peerName);
 		out.writeBoolean(hasPublicAddress());
 		if (hasPublicAddress()) {
 			InetAddress address = publicAddress.getAddress();

src/main/java/com/satergo/ergonnection/records/RawModifier.java

@@ -1,5 +1,6 @@
 package com.satergo.ergonnection.records;
 
+import com.satergo.ergonnection.InternalStreamUtils;
 import com.satergo.ergonnection.VLQInputStream;
 import com.satergo.ergonnection.VLQOutputStream;
 import com.satergo.ergonnection.protocol.ProtocolRecord;
@@ -13,7 +14,7 @@ public record RawModifier(int typeId, byte[] id, byte[] object) implements Proto
 	}
 
 	public static RawModifier deserialize(int typeId, VLQInputStream in) throws IOException {
-		return new RawModifier(typeId, in.readNBytes(32), in.readNBytes((int) in.readUnsignedInt()));
+		return new RawModifier(typeId, in.readNFully(32), in.readNFully((int) in.readUnsignedInt()));
 	}
 
 	@Override