From ceda402e7882a8827038004800d29116186dc1f7 Mon Sep 17 00:00:00 2001
From: Heiko Bornholdt <bornholdt@informatik.uni-hamburg.de>
Date: Sun, 6 Feb 2022 17:28:10 +0100
Subject: [PATCH 1/2] merge HopCount and getArmed into a one byte flags field

---
 .../handler/remote/protocol/HopCount.java     |  2 +-
 .../handler/remote/protocol/PublicHeader.java | 24 +++++++++++++------
 .../handler/remote/protocol/HopCountTest.java |  6 ++---
 3 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/drasyl-core/src/main/java/org/drasyl/handler/remote/protocol/HopCount.java b/drasyl-core/src/main/java/org/drasyl/handler/remote/protocol/HopCount.java
index 49b192c81..0763c1f46 100644
--- a/drasyl-core/src/main/java/org/drasyl/handler/remote/protocol/HopCount.java
+++ b/drasyl-core/src/main/java/org/drasyl/handler/remote/protocol/HopCount.java
@@ -29,7 +29,7 @@ import java.util.Objects;
 @SuppressWarnings("java:S2974")
 public class HopCount implements Comparable<HopCount> {
     public static final byte MIN_HOP_COUNT = 0;
-    public static final byte MAX_HOP_COUNT = 127;
+    public static final byte MAX_HOP_COUNT = 7;
     private final byte value;
 
     private HopCount(final byte value) {
diff --git a/drasyl-core/src/main/java/org/drasyl/handler/remote/protocol/PublicHeader.java b/drasyl-core/src/main/java/org/drasyl/handler/remote/protocol/PublicHeader.java
index fbf0dfa27..81145a6ff 100644
--- a/drasyl-core/src/main/java/org/drasyl/handler/remote/protocol/PublicHeader.java
+++ b/drasyl-core/src/main/java/org/drasyl/handler/remote/protocol/PublicHeader.java
@@ -34,8 +34,7 @@ import org.drasyl.identity.ProofOfWork;
  * This class models the public header of a drasyl protocol message. The header is structured as
  * follows:
  * <ul>
- * <li><b>HopCount</b>: The 1 byte hop count value. Is incremented on each hop. Used to avoid loops.</li>
- * <li><b>Armed</b>: The 1 byte armed value. Indicates, if the message is armed or not.</li>
+ * <li><b>Flags</b>: Several packet flags (bits 1-3: hop count, bit 4: set if message is armed. bits 5-8: unused).</li>
  * <li><b>NetworkId</b>: The 4 bytes network id value. Is a unique network-wide value. Used to filter messages from other networks.</li>
  * <li><b>Nonce</b>: The 24 bytes nonce value. Is used for encryption and as message id.</li>
  * <li><b>Recipient</b>: The 32 bytes recipient address. This value is optional. If not set it MUST be sent as 0.</li>
@@ -47,7 +46,7 @@ import org.drasyl.identity.ProofOfWork;
 @SuppressWarnings({ "java:S118", "java:S2047", "java:S2301" })
 @AutoValue
 public abstract class PublicHeader {
-    public static final int LENGTH = 98;
+    public static final int LENGTH = 97;
 
     public static PublicHeader of(final HopCount hopCount,
                                   final boolean isArmed,
@@ -76,8 +75,12 @@ public abstract class PublicHeader {
         final IdentityPublicKey sender;
         final ProofOfWork proofOfWork;
 
-        hopCount = HopCount.of(byteBuf.readByte());
-        isArmed = byteBuf.readBoolean();
+        byte flags = byteBuf.readByte();
+        // 000. ....
+        hopCount = HopCount.of(flags >> 5);
+        // ...0 ....
+        isArmed = flags >> 4 > 0;
+
         networkId = byteBuf.readInt();
 
         final byte[] nonceBuffer = new byte[Nonce.NONCE_LENGTH];
@@ -142,10 +145,17 @@ public abstract class PublicHeader {
     public void writeTo(final ByteBuf byteBuf, final boolean withHopCount) {
         final byte[] recipientBuffer = getRecipient() == null ? IdentityPublicKey.ZERO_ID.toByteArray() : getRecipient().toByteArray();
 
+        byte flags = 0;
+        // 000. ....
         if (withHopCount) {
-            byteBuf.writeByte(getHopCount().getByte());          //  1 byte
+            flags |= getHopCount().getByte() << 5;
+        }
+        // ...0 ....
+        if (getArmed()) {
+            flags |= 1 << 4;
         }
-        byteBuf.writeBoolean(getArmed())                        //  1 byte
+
+        byteBuf.writeByte(flags)                                //  1 byte
                 .writeInt(getNetworkId())                       //  4 bytes
                 .writeBytes(getNonce().toByteArray())           // 24 bytes
                 .writeBytes(recipientBuffer)                    // 32 bytes
diff --git a/drasyl-core/src/test/java/org/drasyl/handler/remote/protocol/HopCountTest.java b/drasyl-core/src/test/java/org/drasyl/handler/remote/protocol/HopCountTest.java
index 8a7e0b7bf..a14d4852a 100644
--- a/drasyl-core/src/test/java/org/drasyl/handler/remote/protocol/HopCountTest.java
+++ b/drasyl-core/src/test/java/org/drasyl/handler/remote/protocol/HopCountTest.java
@@ -38,7 +38,7 @@ class HopCountTest {
     class Increment {
         @Test
         void shouldIncrementIfNoOverflowOccur() {
-            assertEquals(HopCount.of((byte) 20), HopCount.of((byte) 19).increment());
+            assertEquals(HopCount.of((byte) 5), HopCount.of((byte) 4).increment());
         }
 
         @Test
@@ -55,8 +55,8 @@ class HopCountTest {
             assertEquals(0, HopCount.of(1).compareTo(HopCount.of(1)));
             assertThat(HopCount.of(1).compareTo(HopCount.of(2)), lessThan(0));
             assertThat(HopCount.of(2).compareTo(HopCount.of(1)), greaterThan(0));
-            assertThat(HopCount.of(127).compareTo(HopCount.of(1)), greaterThan(0));
-            assertThat(HopCount.of(1).compareTo(HopCount.of(127)), lessThan(0));
+            assertThat(HopCount.of(7).compareTo(HopCount.of(1)), greaterThan(0));
+            assertThat(HopCount.of(1).compareTo(HopCount.of(7)), lessThan(0));
         }
     }
 
-- 
GitLab


From 4a537c7ba76b6a4dee302c152d53b7df28bde821 Mon Sep 17 00:00:00 2001
From: bornholdt <bornholdt@informatik.uni-hamburg.de>
Date: Fri, 11 Feb 2022 00:55:55 +0100
Subject: [PATCH 2/2] Update PublicHeader.java

---
 .../java/org/drasyl/handler/remote/protocol/PublicHeader.java   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drasyl-core/src/main/java/org/drasyl/handler/remote/protocol/PublicHeader.java b/drasyl-core/src/main/java/org/drasyl/handler/remote/protocol/PublicHeader.java
index 81145a6ff..8b817470d 100644
--- a/drasyl-core/src/main/java/org/drasyl/handler/remote/protocol/PublicHeader.java
+++ b/drasyl-core/src/main/java/org/drasyl/handler/remote/protocol/PublicHeader.java
@@ -34,7 +34,7 @@ import org.drasyl.identity.ProofOfWork;
  * This class models the public header of a drasyl protocol message. The header is structured as
  * follows:
  * <ul>
- * <li><b>Flags</b>: Several packet flags (bits 1-3: hop count, bit 4: set if message is armed. bits 5-8: unused).</li>
+ * <li><b>Flags</b>: Several packet flags (bits 1-3: hop count, bit 4: set if message is armed, bits 5-8: unused).</li>
  * <li><b>NetworkId</b>: The 4 bytes network id value. Is a unique network-wide value. Used to filter messages from other networks.</li>
  * <li><b>Nonce</b>: The 24 bytes nonce value. Is used for encryption and as message id.</li>
  * <li><b>Recipient</b>: The 32 bytes recipient address. This value is optional. If not set it MUST be sent as 0.</li>
-- 
GitLab