Dump a packet's raw hex if entity rewriting fails.

BungeeCord-Patches/0042-Dump-a-packet-s-raw-hex-if-entity-rewriting-fails.patch

@@ -0,0 +1,296 @@
+From 3f7b0d3a64c7e0b7909bb3394954bfa2501ad8fb Mon Sep 17 00:00:00 2001
+From: Techcable <Techcable@techcable.net>
+Date: Fri, 7 Apr 2017 20:19:15 -0700
+Subject: [PATCH] Dump a packet's raw hex if entity rewriting fails.
+
+
+diff --git a/proxy/src/main/java/io/github/waterfallmc/waterfall/utils/BufUtils.java b/proxy/src/main/java/io/github/waterfallmc/waterfall/utils/BufUtils.java
+new file mode 100644
+index 00000000..c21a707a
+--- /dev/null
++++ b/proxy/src/main/java/io/github/waterfallmc/waterfall/utils/BufUtils.java
+@@ -0,0 +1,40 @@
++package io.github.waterfallmc.waterfall.utils;
++
++import java.util.function.Function;
++
++import io.netty.buffer.ByteBuf;
++import net.md_5.bungee.protocol.DefinedPacket;
++
++public final class BufUtils {
++    private BufUtils() {}
++
++    /**
++     * Read a varint from the ByteBuf without changing the index.
++     */
++    public static int peekVarInt(ByteBuf buf) {
++        return peek(buf, DefinedPacket::readVarInt);
++    }
++
++    /**
++     * Read values from the byte buf, then reset it's indexes to the old value.
++     *
++     * This effectively 'peeks' at values ahead of the index.
++     * This is preferable to `resetWriterIndex` and `resetReaderIndex`,
++     * since it doesn't rely on the buffer's mark.
++     *
++     * @param buf the buffer to peek from
++     * @param func the function that should peek values
++     * @return the value returned from the function
++     * @throws Throwable any exception thrown by the callable
++     */
++    public static <R> R peek(ByteBuf buf, Function<ByteBuf, R> func) {
++        int oldReaderIndex = buf.readerIndex();
++        int oldWriterIndex = buf.writerIndex();
++        try {
++            return func.apply(buf);
++        } finally {
++            buf.readerIndex(oldReaderIndex);
++            buf.writerIndex(oldWriterIndex);
++        }
++    }
++}
+diff --git a/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap.java b/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap.java
+index d98a8056..736bd599 100644
+--- a/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap.java
++++ b/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap.java
+@@ -10,6 +10,12 @@ import lombok.AccessLevel;
+ import lombok.NoArgsConstructor;
+ import net.md_5.bungee.protocol.DefinedPacket;
+ import net.md_5.bungee.protocol.ProtocolConstants;
++// Waterfall start
++import io.github.waterfallmc.waterfall.utils.BufUtils;
++import io.netty.buffer.ByteBufUtil;
++import io.netty.handler.codec.DecoderException;
++import net.md_5.bungee.protocol.BadPacketException;
++// Waterfall end
+ 
+ /**
+  * Class to rewrite integers within packets.
+@@ -66,13 +72,51 @@ public abstract class EntityMap
+         }
+     }
+ 
+-    public void rewriteServerbound(ByteBuf packet, int oldId, int newId)
++    // Waterfall start - wrap rewrite calls to provide descriptive error messages
++    public final void rewriteServerbound(ByteBuf packet, int oldId, int newId) {
++        Integer packetId = null;
++        ByteBuf originalPacket = packet.copy(); // EntityMap modifies in place, so we need a copy :(
++        try {
++            packetId = BufUtils.peekVarInt(packet);
++            rewriteServerbound0(packet, oldId, newId);
++        } catch (BadPacketException | IndexOutOfBoundsException e) {
++            String packetType = packetId != null ? "id " + Integer.toHexString(packetId) : "unknown";
++            throw new DecoderException(
++                "Error rewriting packet "
++                + packetType
++                + " with contents:\n"
++                + ByteBufUtil.prettyHexDump(originalPacket),
++                e
++            );
++        }
++    }
++
++    public final void rewriteClientbound(ByteBuf packet, int oldId, int newId) {
++        Integer packetId = null;
++        ByteBuf originalPacket = packet.copy(); // EntityMap modifies in place, so we need a copy :(
++        try {
++            packetId = BufUtils.peekVarInt(packet);
++            rewriteClientbound0(packet, oldId, newId);
++        } catch (BadPacketException | IndexOutOfBoundsException e) {
++            String packetType = packetId != null ? "id " + Integer.toHexString(packetId) : "unknown";
++            throw new DecoderException(
++                "Error rewriting packet "
++                + packetType
++                + " with contents:\n"
++                + ByteBufUtil.prettyHexDump(originalPacket),
++                e
++            );
++        }
++    }
++
++    protected void rewriteServerbound0(ByteBuf packet, int oldId, int newId)
+     {
+         rewrite( packet, oldId, newId, serverboundInts, serverboundVarInts );
+     }
+ 
+-    public void rewriteClientbound(ByteBuf packet, int oldId, int newId)
++    protected void rewriteClientbound0(ByteBuf packet, int oldId, int newId)
+     {
++        // Waterfall end
+         rewrite( packet, oldId, newId, clientboundInts, clientboundVarInts );
+     }
+ 
+diff --git a/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_10.java b/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_10.java
+index a89ea2e9..0de5ce25 100644
+--- a/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_10.java
++++ b/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_10.java
+@@ -49,9 +49,11 @@ class EntityMap_1_10 extends EntityMap
+ 
+     @Override
+     @SuppressFBWarnings("DLS_DEAD_LOCAL_STORE")
+-    public void rewriteClientbound(ByteBuf packet, int oldId, int newId)
++    // Waterfall start - rewriteClientbound -> rewriteClientbound0
++    protected void rewriteClientbound0(ByteBuf packet, int oldId, int newId)
+     {
+-        super.rewriteClientbound( packet, oldId, newId );
++        super.rewriteClientbound0( packet, oldId, newId );
++        // Waterfall end
+ 
+         // Special cases
+         int readerIndex = packet.readerIndex();
+@@ -151,10 +153,13 @@ class EntityMap_1_10 extends EntityMap
+         packet.readerIndex( readerIndex );
+     }
+ 
++    // Waterfall start - rewriteServerbound -> rewriteServerbound0
+     @Override
+-    public void rewriteServerbound(ByteBuf packet, int oldId, int newId)
++    public void rewriteServerbound0(ByteBuf packet, int oldId, int newId)
+     {
+-        super.rewriteServerbound( packet, oldId, newId );
++        super.rewriteServerbound0( packet, oldId, newId );
++        // Waterfall end
++
+         // Special cases
+         int readerIndex = packet.readerIndex();
+         int packetId = DefinedPacket.readVarInt( packet );
+diff --git a/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_11.java b/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_11.java
+index 260da17e..8a746116 100644
+--- a/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_11.java
++++ b/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_11.java
+@@ -49,9 +49,11 @@ class EntityMap_1_11 extends EntityMap
+ 
+     @Override
+     @SuppressFBWarnings("DLS_DEAD_LOCAL_STORE")
+-    public void rewriteClientbound(ByteBuf packet, int oldId, int newId)
++    // Waterfall start - rewriteClientbound -> rewriteClientbound0
++    protected void rewriteClientbound0(ByteBuf packet, int oldId, int newId)
+     {
+-        super.rewriteClientbound( packet, oldId, newId );
++        super.rewriteClientbound0( packet, oldId, newId );
++        // Waterfall end
+ 
+         // Special cases
+         int readerIndex = packet.readerIndex();
+@@ -155,10 +157,13 @@ class EntityMap_1_11 extends EntityMap
+         packet.readerIndex( readerIndex );
+     }
+ 
++    // Waterfall start - rewriteServerbound -> rewriteServerbound0
+     @Override
+-    public void rewriteServerbound(ByteBuf packet, int oldId, int newId)
++    public void rewriteServerbound0(ByteBuf packet, int oldId, int newId)
+     {
+-        super.rewriteServerbound( packet, oldId, newId );
++        super.rewriteServerbound0( packet, oldId, newId );
++        // Waterfall end
++
+         // Special cases
+         int readerIndex = packet.readerIndex();
+         int packetId = DefinedPacket.readVarInt( packet );
+diff --git a/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_8.java b/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_8.java
+index 4229fefa..23f29a4b 100644
+--- a/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_8.java
++++ b/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_8.java
+@@ -49,9 +49,11 @@ class EntityMap_1_8 extends EntityMap
+ 
+     @Override
+     @SuppressFBWarnings("DLS_DEAD_LOCAL_STORE")
+-    public void rewriteClientbound(ByteBuf packet, int oldId, int newId)
++    // Waterfall start - rewriteClientbound -> rewriteClientbound0
++    protected void rewriteClientbound0(ByteBuf packet, int oldId, int newId)
+     {
+-        super.rewriteClientbound( packet, oldId, newId );
++        super.rewriteClientbound0( packet, oldId, newId );
++        // Waterfall end
+ 
+         //Special cases
+         int readerIndex = packet.readerIndex();
+@@ -149,10 +151,13 @@ class EntityMap_1_8 extends EntityMap
+         packet.readerIndex( readerIndex );
+     }
+ 
++    // Waterfall start - rewriteServerbound -> rewriteServerbound0
+     @Override
+-    public void rewriteServerbound(ByteBuf packet, int oldId, int newId)
++    public void rewriteServerbound0(ByteBuf packet, int oldId, int newId)
+     {
+-        super.rewriteServerbound( packet, oldId, newId );
++        super.rewriteServerbound0( packet, oldId, newId );
++        // Waterfall end
++
+         //Special cases
+         int readerIndex = packet.readerIndex();
+         int packetId = DefinedPacket.readVarInt( packet );
+diff --git a/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_9.java b/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_9.java
+index 19d96776..80075eb4 100644
+--- a/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_9.java
++++ b/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_9.java
+@@ -49,9 +49,11 @@ class EntityMap_1_9 extends EntityMap
+ 
+     @Override
+     @SuppressFBWarnings("DLS_DEAD_LOCAL_STORE")
+-    public void rewriteClientbound(ByteBuf packet, int oldId, int newId)
++    // Waterfall start - rewriteClientbound -> rewriteClientbound0
++    protected void rewriteClientbound0(ByteBuf packet, int oldId, int newId)
+     {
+-        super.rewriteClientbound( packet, oldId, newId );
++        super.rewriteClientbound0( packet, oldId, newId );
++        // Waterfall end
+ 
+         // Special cases
+         int readerIndex = packet.readerIndex();
+@@ -151,10 +153,13 @@ class EntityMap_1_9 extends EntityMap
+         packet.readerIndex( readerIndex );
+     }
+ 
++    // Waterfall start - rewriteServerbound -> rewriteServerbound0
+     @Override
+-    public void rewriteServerbound(ByteBuf packet, int oldId, int newId)
++    public void rewriteServerbound0(ByteBuf packet, int oldId, int newId)
+     {
+-        super.rewriteServerbound( packet, oldId, newId );
++        super.rewriteServerbound0( packet, oldId, newId );
++        // Waterfall end
++
+         // Special cases
+         int readerIndex = packet.readerIndex();
+         int packetId = DefinedPacket.readVarInt( packet );
+diff --git a/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_9_4.java b/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_9_4.java
+index 412ab4ed..ae5ce7f0 100644
+--- a/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_9_4.java
++++ b/proxy/src/main/java/net/md_5/bungee/entitymap/EntityMap_1_9_4.java
+@@ -49,9 +49,11 @@ class EntityMap_1_9_4 extends EntityMap
+ 
+     @Override
+     @SuppressFBWarnings("DLS_DEAD_LOCAL_STORE")
+-    public void rewriteClientbound(ByteBuf packet, int oldId, int newId)
++    // Waterfall start - rewriteClientbound -> rewriteClientbound0
++    protected void rewriteClientbound0(ByteBuf packet, int oldId, int newId)
+     {
+-        super.rewriteClientbound( packet, oldId, newId );
++        super.rewriteClientbound0( packet, oldId, newId );
++        // Waterfall end
+ 
+         // Special cases
+         int readerIndex = packet.readerIndex();
+@@ -151,10 +153,13 @@ class EntityMap_1_9_4 extends EntityMap
+         packet.readerIndex( readerIndex );
+     }
+ 
++    // Waterfall start - rewriteServerbound -> rewriteServerbound0
+     @Override
+-    public void rewriteServerbound(ByteBuf packet, int oldId, int newId)
++    public void rewriteServerbound0(ByteBuf packet, int oldId, int newId)
+     {
+-        super.rewriteServerbound( packet, oldId, newId );
++        super.rewriteServerbound0( packet, oldId, newId );
++        // Waterfall end
++
+         // Special cases
+         int readerIndex = packet.readerIndex();
+         int packetId = DefinedPacket.readVarInt( packet );
+-- 
+2.12.2
+