Add TCP options

Author: hirsivaja

src/main/java/com/github/hirsivaja/ip/tcp/TcpHeader.java

@@ -1,7 +1,9 @@
 package com.github.hirsivaja.ip.tcp;
 
-import com.github.hirsivaja.ip.ByteArray;
+import com.github.hirsivaja.ip.tcp.option.TcpOption;
 import java.nio.ByteBuffer;
+import java.util.ArrayList;
+import java.util.List;
 
 public record TcpHeader(
         short srcPort,
@@ -12,37 +14,40 @@ public record TcpHeader(
         short windowSize,
         short checksum,
         short urgentPointer,
-        ByteArray options) {
+        List<TcpOption> options) {
     public static final int TCP_HEADER_LEN = 20;
     private static final int DATA_OFFSET_SHIFT = 4;
 
-    @SuppressWarnings("squid:S00107")
     public TcpHeader(short srcPort, short dstPort, int sequenceNumber, int ackNumber, TcpFlags flags, short windowSize,
-                     short urgentPointer, byte[] options) {
-        this(srcPort, dstPort, sequenceNumber, ackNumber, flags, windowSize, (short) 0, urgentPointer, options);
+                     short urgentPointer) {
+        this(srcPort, dstPort, sequenceNumber, ackNumber, flags, windowSize, (short) 0, urgentPointer, List.of());
     }
 
     @SuppressWarnings("squid:S00107")
     public TcpHeader(short srcPort, short dstPort, int sequenceNumber, int ackNumber, TcpFlags flags, short windowSize,
-                     short checksum, short urgentPointer, byte[] options) {
-        this(srcPort, dstPort, sequenceNumber, ackNumber, flags, windowSize, checksum, urgentPointer, new ByteArray(options));
+                     short urgentPointer, List<TcpOption> options) {
+        this(srcPort, dstPort, sequenceNumber, ackNumber, flags, windowSize, (short) 0, urgentPointer, options);
     }
 
     public void encode(ByteBuffer out) {
         out.putShort(srcPort);
         out.putShort(dstPort);
         out.putInt(sequenceNumber);
         out.putInt(ackNumber);
-        out.put((byte) (((options.array().length / 4) + 5) << DATA_OFFSET_SHIFT));
+        out.put((byte) (((optionsLength() / 4) + 5) << DATA_OFFSET_SHIFT));
         out.put(flags.toByte());
         out.putShort(windowSize);
         out.putShort(checksum);
         out.putShort(urgentPointer);
-        out.put(options.array());
+        options.forEach(option -> option.encode(out));
     }
 
     public int length() {
-        return TCP_HEADER_LEN + options.array().length;
+        return TCP_HEADER_LEN + optionsLength();
+    }
+
+    public int optionsLength() {
+        return options.stream().mapToInt(TcpOption::length).sum();
     }
 
     public static TcpHeader decode(ByteBuffer in) {
@@ -55,15 +60,19 @@ public static TcpHeader decode(ByteBuffer in) {
         short windowSize = in.getShort();
         short checksum = in.getShort();
         short urgentPointer = in.getShort();
-        byte[] options = new byte[(dataOffset - 5) * 4];
-        in.get(options);
+        List<TcpOption> options = new ArrayList<>();
+        int optionsLength = (dataOffset - 5) * 4;
+        while(optionsLength > 0) {
+            TcpOption option = TcpOption.decode(in);
+            options.add(option);
+            optionsLength -= option.length();
+        }
+        if(optionsLength != 0) {
+            throw new IllegalArgumentException("Could not decode options for the TCP header.");
+        }
         return new TcpHeader(srcPort, dstPort, sequenceNumber, ackNumber, flags, windowSize, checksum, urgentPointer, options);
     }
 
-    public byte[] rawOptions() {
-        return options.array();
-    }
-
     public int uSrcPort() {
         return Short.toUnsignedInt(srcPort);
     }

src/main/java/com/github/hirsivaja/ip/tcp/TcpMessagePayload.java

@@ -25,7 +25,7 @@ public TcpMessagePayload(IpHeader header, TcpHeader tcpHeader, ByteArray payload
                 tcpHeader.checksum();
         this.tcpHeader = new TcpHeader(tcpHeader.srcPort(), tcpHeader.dstPort(), tcpHeader.sequenceNumber(),
                 tcpHeader.ackNumber(), tcpHeader.flags(), tcpHeader.windowSize(), checksum,
-                tcpHeader.urgentPointer(), tcpHeader.rawOptions());
+                tcpHeader.urgentPointer(), tcpHeader.options());
         this.payload = payload;
     }
 

src/main/java/com/github/hirsivaja/ip/tcp/option/EncryptionNegotiation.java

@@ -0,0 +1,34 @@
+package com.github.hirsivaja.ip.tcp.option;
+
+import com.github.hirsivaja.ip.ByteArray;
+import java.nio.ByteBuffer;
+
+public record EncryptionNegotiation(ByteArray data) implements TcpOption {
+
+    public EncryptionNegotiation(byte[] data) {
+        this(new ByteArray(data));
+    }
+
+    @Override
+    public void encode(ByteBuffer out) {
+        out.put(optionType().type());
+        out.put((byte) (length()));
+        out.put(data.array());
+    }
+
+    @Override
+    public int length() {
+        return 2 + data.length();
+    }
+
+    @Override
+    public TcpOptionType optionType() {
+        return TcpOptionType.ENCRYPTION_NEGOTIATION;
+    }
+
+    public static EncryptionNegotiation decode(ByteBuffer in){
+        byte[] data = new byte[in.remaining()];
+        in.get(data);
+        return new EncryptionNegotiation(data);
+    }
+}

src/main/java/com/github/hirsivaja/ip/tcp/option/Eool.java

@@ -0,0 +1,25 @@
+package com.github.hirsivaja.ip.tcp.option;
+
+import java.nio.ByteBuffer;
+
+public record Eool() implements TcpOption {
+
+    @Override
+    public void encode(ByteBuffer out) {
+        out.put(optionType().type());
+    }
+
+    @Override
+    public int length() {
+        return 1;
+    }
+
+    @Override
+    public TcpOptionType optionType() {
+        return TcpOptionType.END_OF_OPTIONS_LIST;
+    }
+
+    public static TcpOption decode() {
+        return new Eool();
+    }
+}

src/main/java/com/github/hirsivaja/ip/tcp/option/GenericTcpOption.java

@@ -0,0 +1,29 @@
+package com.github.hirsivaja.ip.tcp.option;
+
+import com.github.hirsivaja.ip.ByteArray;
+import java.nio.ByteBuffer;
+
+public record GenericTcpOption(TcpOptionType optionType, ByteArray data) implements TcpOption {
+
+    public GenericTcpOption(TcpOptionType optionType, byte[] data) {
+        this(optionType, new ByteArray(data));
+    }
+
+    @Override
+    public void encode(ByteBuffer out) {
+        out.put(optionType().type());
+        out.put((byte) (length()));
+        out.put(data.array());
+    }
+
+    @Override
+    public int length() {
+        return data.length() + 2;
+    }
+
+    public static GenericTcpOption decode(ByteBuffer in, TcpOptionType optionType){
+        byte[] data = new byte[in.remaining()];
+        in.get(data);
+        return new GenericTcpOption(optionType, data);
+    }
+}

src/main/java/com/github/hirsivaja/ip/tcp/option/MaximumSegmentSize.java

@@ -0,0 +1,28 @@
+package com.github.hirsivaja.ip.tcp.option;
+
+import java.nio.ByteBuffer;
+
+public record MaximumSegmentSize(short maximumSegmentSize) implements TcpOption {
+
+    @Override
+    public void encode(ByteBuffer out) {
+        out.put(optionType().type());
+        out.put((byte) (length()));
+        out.putShort(maximumSegmentSize);
+    }
+
+    @Override
+    public int length() {
+        return 4;
+    }
+
+    @Override
+    public TcpOptionType optionType() {
+        return TcpOptionType.MAXIMUM_SEGMENT_SIZE;
+    }
+
+    public static MaximumSegmentSize decode(ByteBuffer in){
+        short maximumSegmentSize = in.getShort();
+        return new MaximumSegmentSize(maximumSegmentSize);
+    }
+}

src/main/java/com/github/hirsivaja/ip/tcp/option/MultipathTcp.java

@@ -0,0 +1,34 @@
+package com.github.hirsivaja.ip.tcp.option;
+
+import com.github.hirsivaja.ip.ByteArray;
+import java.nio.ByteBuffer;
+
+public record MultipathTcp(ByteArray subtypeData) implements TcpOption {
+
+    public MultipathTcp(byte[] subtypeData) {
+        this(new ByteArray(subtypeData));
+    }
+
+    @Override
+    public void encode(ByteBuffer out) {
+        out.put(optionType().type());
+        out.put((byte) (length()));
+        out.put(subtypeData.array());
+    }
+
+    @Override
+    public int length() {
+        return 2 + subtypeData.length();
+    }
+
+    @Override
+    public TcpOptionType optionType() {
+        return TcpOptionType.MULTIPATH_TCP;
+    }
+
+    public static MultipathTcp decode(ByteBuffer in){
+        byte[] subtypeData = new byte[in.remaining()];
+        in.get(subtypeData);
+        return new MultipathTcp(subtypeData);
+    }
+}

src/main/java/com/github/hirsivaja/ip/tcp/option/Nop.java

@@ -0,0 +1,25 @@
+package com.github.hirsivaja.ip.tcp.option;
+
+import java.nio.ByteBuffer;
+
+public record Nop() implements TcpOption {
+
+    @Override
+    public void encode(ByteBuffer out) {
+        out.put(optionType().type());
+    }
+
+    @Override
+    public int length() {
+        return 1;
+    }
+
+    @Override
+    public TcpOptionType optionType() {
+        return TcpOptionType.NO_OPERATION;
+    }
+
+    public static TcpOption decode() {
+        return new Nop();
+    }
+}

src/main/java/com/github/hirsivaja/ip/tcp/option/QuickStart.java

@@ -0,0 +1,32 @@
+package com.github.hirsivaja.ip.tcp.option;
+
+import java.nio.ByteBuffer;
+
+public record QuickStart(byte functionAndRateRequest, byte qsTtl, int qsNonce) implements TcpOption {
+
+    @Override
+    public void encode(ByteBuffer out) {
+        out.put(optionType().type());
+        out.put((byte) (length() - 2));
+        out.put(functionAndRateRequest);
+        out.put(qsTtl);
+        out.putInt(qsNonce);
+    }
+
+    @Override
+    public int length() {
+        return 8;
+    }
+
+    @Override
+    public TcpOptionType optionType() {
+        return TcpOptionType.QUICK_START_RESPONSE;
+    }
+
+    public static TcpOption decode(ByteBuffer in) {
+        byte functionAndRateRequest = in.get();
+        byte qsTtl = in.get();
+        int qsNonce = in.getInt();
+        return new QuickStart(functionAndRateRequest, qsTtl, qsNonce);
+    }
+}

src/main/java/com/github/hirsivaja/ip/tcp/option/Sack.java

@@ -0,0 +1,33 @@
+package com.github.hirsivaja.ip.tcp.option;
+
+import java.nio.ByteBuffer;
+import java.util.ArrayList;
+import java.util.List;
+
+public record Sack(List<Integer> blocks) implements TcpOption {
+
+    @Override
+    public void encode(ByteBuffer out) {
+        out.put(optionType().type());
+        out.put((byte) (length()));
+        blocks.forEach(out::putInt);
+    }
+
+    @Override
+    public int length() {
+        return 2 + 4 * blocks.size();
+    }
+
+    @Override
+    public TcpOptionType optionType() {
+        return TcpOptionType.SACK;
+    }
+
+    public static Sack decode(ByteBuffer in){
+        List<Integer> blocks = new ArrayList<>();
+        for(int i = 0; i < in.remaining() / 4; i++) {
+            blocks.add(in.getInt());
+        }
+        return new Sack(blocks);
+    }
+}