Revert "Disable io_uring transport by default"

This reverts commit ae312339a3.

api/src/main/java/com/velocitypowered/api/proxy/messages/MinecraftChannelIdentifier.java

@@ -11,7 +11,6 @@ import static com.google.common.base.Preconditions.checkArgument;
 
 import com.google.common.base.Strings;
 import java.util.Objects;
-import java.util.regex.Pattern;
 import net.kyori.adventure.key.Key;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
@@ -21,8 +20,6 @@ import org.checkerframework.checker.nullness.qual.Nullable;
  */
 public final class MinecraftChannelIdentifier implements ChannelIdentifier {
 
-  private static final Pattern VALID_IDENTIFIER_REGEX = Pattern.compile("[a-z0-9/\\-_]*");
-
   private final String namespace;
   private final String name;
 
@@ -39,7 +36,7 @@ public final class MinecraftChannelIdentifier implements ChannelIdentifier {
    * @return a new channel identifier
    */
   public static MinecraftChannelIdentifier forDefaultNamespace(String name) {
-    return new MinecraftChannelIdentifier("minecraft", name);
+    return new MinecraftChannelIdentifier(Key.MINECRAFT_NAMESPACE, name);
   }
 
   /**
@@ -52,14 +49,10 @@ public final class MinecraftChannelIdentifier implements ChannelIdentifier {
   public static MinecraftChannelIdentifier create(String namespace, String name) {
     checkArgument(!Strings.isNullOrEmpty(namespace), "namespace is null or empty");
     checkArgument(name != null, "namespace is null or empty");
-    checkArgument(VALID_IDENTIFIER_REGEX.matcher(namespace).matches(),
-        "namespace is not valid, must match: %s got %s",
-        VALID_IDENTIFIER_REGEX.toString(),
-        namespace);
-    checkArgument(VALID_IDENTIFIER_REGEX.matcher(name).matches(),
-        "name is not valid, must match: %s got %s",
-        VALID_IDENTIFIER_REGEX.toString(),
-        name);
+    checkArgument(Key.parseableNamespace(namespace),
+        "namespace is not valid, must match: [a-z0-9_.-] got %s", namespace);
+    checkArgument(Key.parseableValue(name),
+        "name is not valid, must match: [a-z0-9/._-] got %s", name);
     return new MinecraftChannelIdentifier(namespace, name);
   }
 
@@ -72,10 +65,9 @@ public final class MinecraftChannelIdentifier implements ChannelIdentifier {
   public static MinecraftChannelIdentifier from(String identifier) {
     int colonPos = identifier.indexOf(':');
     if (colonPos == -1) {
-      throw new IllegalArgumentException("Identifier does not contain a colon.");
-    }
-    if (colonPos + 1 == identifier.length()) {
-      throw new IllegalArgumentException("Identifier is empty.");
+      return create(Key.MINECRAFT_NAMESPACE, identifier);
+    } else if (colonPos == 0) {
+      return create(Key.MINECRAFT_NAMESPACE, identifier.substring(1));
     }
     String namespace = identifier.substring(0, colonPos);
     String name = identifier.substring(colonPos + 1);

api/src/main/java/com/velocitypowered/api/proxy/server/ServerPing.java

@@ -31,6 +31,7 @@ public final class ServerPing {
   private final net.kyori.adventure.text.Component description;
   private final @Nullable Favicon favicon;
   private final @Nullable ModInfo modinfo;
+  private final boolean preventsChatReports = true;
 
   public ServerPing(Version version, @Nullable Players players,
       net.kyori.adventure.text.Component description, @Nullable Favicon favicon) {

api/src/test/java/com/velocitypowered/api/proxy/messages/MinecraftChannelIdentifierTest.java

@@ -47,17 +47,25 @@ class MinecraftChannelIdentifierTest {
     create("velocity", "test/test2");
   }
 
+  @Test
+  void fromIdentifierDefaultNamespace() {
+    assertEquals("minecraft", from("test").getNamespace());
+    assertEquals("minecraft", from(":test").getNamespace());
+  }
+
+  @Test
+  void fromIdentifierAllowsEmptyName() {
+    from("minecraft:");
+    from(":");
+    from("");
+  }
+
   @Test
   void fromIdentifierThrowsOnBadValues() {
     assertAll(
-        () -> assertThrows(IllegalArgumentException.class, () -> from("")),
-        () -> assertThrows(IllegalArgumentException.class, () -> from(":")),
-        () -> assertThrows(IllegalArgumentException.class, () -> from(":a")),
-        () -> assertThrows(IllegalArgumentException.class, () -> from("a:")),
         () -> assertThrows(IllegalArgumentException.class, () -> from("hello:$$$$$$")),
+        () -> assertThrows(IllegalArgumentException.class, () -> from("he/llo:wor/ld")),
         () -> assertThrows(IllegalArgumentException.class, () -> from("hello::"))
     );
   }
-
-
-}
+}

proxy/src/main/java/com/velocitypowered/proxy/connection/MinecraftConnection.java

@@ -84,6 +84,7 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
   private static final Logger logger = LogManager.getLogger(MinecraftConnection.class);
 
   private final Channel channel;
+  public boolean pendingConfigurationSwitch = false;
   private SocketAddress remoteAddress;
   private StateRegistry state;
   private Map<StateRegistry, MinecraftSessionHandler> sessionHandlers;

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BackendPlaySessionHandler.java

@@ -34,6 +34,8 @@ import com.velocitypowered.api.event.player.ServerResourcePackSendEvent;
 import com.velocitypowered.api.event.proxy.ProxyPingEvent;
 import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
+import com.velocitypowered.api.proxy.messages.LegacyChannelIdentifier;
+import com.velocitypowered.api.proxy.messages.MinecraftChannelIdentifier;
 import com.velocitypowered.api.proxy.player.ResourcePackInfo;
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.command.CommandGraphInjector;
@@ -288,31 +290,14 @@ public class BackendPlaySessionHandler implements MinecraftSessionHandler {
       return true;
     }
 
-    // Register and unregister packets are simply forwarded to the server as-is.
-    if (PluginMessageUtil.isRegister(packet) || PluginMessageUtil.isUnregister(packet)) {
-      return false;
-    }
-
-    if (PluginMessageUtil.isMcBrand(packet)) {
-      PluginMessagePacket rewritten = PluginMessageUtil
-              .rewriteMinecraftBrand(packet,
-                      server.getVersion(), playerConnection.getProtocolVersion());
-      playerConnection.write(rewritten);
-      return true;
-    }
-
     if (serverConn.getPhase().handle(serverConn, serverConn.getPlayer(), packet)) {
       // Handled.
       return true;
     }
 
-    ChannelIdentifier id = server.getChannelRegistrar().getFromId(packet.getChannel());
-    if (id == null) {
-      return false;
-    }
-
     byte[] copy = ByteBufUtil.getBytes(packet.content());
-    PluginMessageEvent event = new PluginMessageEvent(serverConn, serverConn.getPlayer(), id, copy);
+    String channel = packet.getChannel();
+    PluginMessageEvent event = new PluginMessageEvent(serverConn, serverConn.getPlayer(), channel.indexOf(':') == -1 ? new LegacyChannelIdentifier(channel) : MinecraftChannelIdentifier.from(channel), copy);
     server.getEventManager().fire(event).thenAcceptAsync(pme -> {
       if (pme.getResult().isAllowed() && !playerConnection.isClosed()) {
         PluginMessagePacket copied = new PluginMessagePacket(

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/BungeeCordMessageResponder.java

@@ -20,6 +20,7 @@ package com.velocitypowered.proxy.connection.backend;
 import com.velocitypowered.api.network.ProtocolVersion;
 import com.velocitypowered.api.proxy.Player;
 import com.velocitypowered.api.proxy.ServerConnection;
+import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
 import com.velocitypowered.api.proxy.messages.LegacyChannelIdentifier;
 import com.velocitypowered.api.proxy.messages.MinecraftChannelIdentifier;
 import com.velocitypowered.api.proxy.server.RegisteredServer;
@@ -316,9 +317,9 @@ public class BungeeCordMessageResponder {
     });
   }
 
-  static String getBungeeCordChannel(ProtocolVersion version) {
-    return version.noLessThan(ProtocolVersion.MINECRAFT_1_13) ? MODERN_CHANNEL.getId()
-        : LEGACY_CHANNEL.getId();
+  static ChannelIdentifier getBungeeCordChannel(ProtocolVersion version) {
+    return version.noLessThan(ProtocolVersion.MINECRAFT_1_13) ? MODERN_CHANNEL
+        : LEGACY_CHANNEL;
   }
 
   // Note: this method will always release the buffer!
@@ -329,8 +330,8 @@ public class BungeeCordMessageResponder {
   // Note: this method will always release the buffer!
   private static void sendServerResponse(ConnectedPlayer player, ByteBuf buf) {
     MinecraftConnection serverConnection = player.ensureAndGetCurrentServer().ensureConnected();
-    String chan = getBungeeCordChannel(serverConnection.getProtocolVersion());
-    PluginMessagePacket msg = new PluginMessagePacket(chan, buf);
+    ChannelIdentifier chan = getBungeeCordChannel(serverConnection.getProtocolVersion());
+    PluginMessagePacket msg = new PluginMessagePacket(chan.getId(), buf);
     serverConnection.write(msg);
   }
 

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java

@@ -74,6 +74,7 @@ import com.velocitypowered.proxy.protocol.packet.config.FinishedUpdatePacket;
 import com.velocitypowered.proxy.protocol.packet.title.GenericTitlePacket;
 import com.velocitypowered.proxy.protocol.util.PluginMessageUtil;
 import com.velocitypowered.proxy.util.CharacterUtil;
+import com.velocitypowered.proxy.util.except.QuietRuntimeException;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.ByteBufUtil;
 import io.netty.buffer.Unpooled;
@@ -162,7 +163,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
   @Override
   public void activated() {
     configSwitchFuture = new CompletableFuture<>();
-    Collection<String> channels =
+    Collection<ChannelIdentifier> channels =
         server.getChannelRegistrar().getChannelsForProtocol(player.getProtocolVersion());
     if (!channels.isEmpty()) {
       PluginMessagePacket register = constructChannelsPacket(player.getProtocolVersion(), channels);
@@ -310,22 +311,17 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
         logger.warn("A plugin message was received while the backend server was not "
             + "ready. Channel: {}. Packet discarded.", packet.getChannel());
       } else if (PluginMessageUtil.isRegister(packet)) {
-        List<String> channels = PluginMessageUtil.getChannels(packet);
+        List<ChannelIdentifier> channels =
+            PluginMessageUtil.getChannels(this.player.getClientsideChannels().size(), packet,
+                this.player.getProtocolVersion());
         player.getClientsideChannels().addAll(channels);
-        List<ChannelIdentifier> channelIdentifiers = new ArrayList<>();
-        for (String channel : channels) {
-          try {
-            channelIdentifiers.add(MinecraftChannelIdentifier.from(channel));
-          } catch (IllegalArgumentException e) {
-            channelIdentifiers.add(new LegacyChannelIdentifier(channel));
-          }
-        }
         server.getEventManager()
             .fireAndForget(
-                new PlayerChannelRegisterEvent(player, ImmutableList.copyOf(channelIdentifiers)));
+                new PlayerChannelRegisterEvent(player, ImmutableList.copyOf(channels)));
         backendConn.write(packet.retain());
       } else if (PluginMessageUtil.isUnregister(packet)) {
-        player.getClientsideChannels().removeAll(PluginMessageUtil.getChannels(packet));
+        player.getClientsideChannels()
+            .removeAll(PluginMessageUtil.getChannels(0, packet, this.player.getProtocolVersion()));
         backendConn.write(packet.retain());
       } else if (PluginMessageUtil.isMcBrand(packet)) {
         String brand = PluginMessageUtil.readBrandMessage(packet.content());
@@ -345,43 +341,25 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
         }
 
         if (!player.getPhase().handle(player, packet, serverConn)) {
-          ChannelIdentifier id = server.getChannelRegistrar().getFromId(packet.getChannel());
-          if (id == null) {
-            // We don't have any plugins listening on this channel, process the packet now.
-            if (!player.getPhase().consideredComplete() || !serverConn.getPhase()
-                .consideredComplete()) {
-              // The client is trying to send messages too early. This is primarily caused by mods,
-              // but further aggravated by Velocity. To work around these issues, we will queue any
-              // non-FML handshake messages to be sent once the FML handshake has completed or the
-              // JoinGame packet has been received by the proxy, whichever comes first.
-              //
-              // We also need to make sure to retain these packets, so they can be flushed
-              // appropriately.
-              loginPluginMessages.add(packet.retain());
-            } else {
-              // The connection is ready, send the packet now.
-              backendConn.write(packet.retain());
-            }
-          } else {
-            byte[] copy = ByteBufUtil.getBytes(packet.content());
-            PluginMessageEvent event = new PluginMessageEvent(player, serverConn, id, copy);
-            server.getEventManager().fire(event).thenAcceptAsync(pme -> {
-              if (pme.getResult().isAllowed()) {
-                PluginMessagePacket message = new PluginMessagePacket(packet.getChannel(),
-                    Unpooled.wrappedBuffer(copy));
-                if (!player.getPhase().consideredComplete() || !serverConn.getPhase()
-                    .consideredComplete()) {
-                  // We're still processing the connection (see above), enqueue the packet for now.
-                  loginPluginMessages.add(message.retain());
-                } else {
-                  backendConn.write(message);
-                }
+          byte[] copy = ByteBufUtil.getBytes(packet.content());
+          String channel = packet.getChannel();
+          PluginMessageEvent event = new PluginMessageEvent(player, serverConn, channel.indexOf(':') == -1 ? new LegacyChannelIdentifier(channel) : MinecraftChannelIdentifier.from(channel), copy);
+          server.getEventManager().fire(event).thenAcceptAsync(pme -> {
+            if (pme.getResult().isAllowed()) {
+              PluginMessagePacket message = new PluginMessagePacket(packet.getChannel(),
+                      Unpooled.wrappedBuffer(copy));
+              if (!player.getPhase().consideredComplete() || !serverConn.getPhase()
+                      .consideredComplete()) {
+                // We're still processing the connection (see above), enqueue the packet for now.
+                loginPluginMessages.add(message.retain());
+              } else {
+                backendConn.write(message);
               }
-            }, backendConn.eventLoop()).exceptionally((ex) -> {
-              logger.error("Exception while handling plugin message packet for {}", player, ex);
-              return null;
-            });
-          }
+            }
+          }, backendConn.eventLoop()).exceptionally((ex) -> {
+            logger.error("Exception while handling plugin message packet for {}", player, ex);
+            return null;
+          });
         }
       }
     }
@@ -399,10 +377,14 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
 
   @Override
   public boolean handle(FinishedUpdatePacket packet) {
+    if (!player.getConnection().pendingConfigurationSwitch) {
+      throw new QuietRuntimeException("Not expecting reconfiguration");
+    }
     // Complete client switch
     player.getConnection().setActiveSessionHandler(StateRegistry.CONFIG);
     VelocityServerConnection serverConnection = player.getConnectedServer();
-    server.getEventManager().fireAndForget(new PlayerEnteredConfigurationEvent(player, serverConnection));
+    server.getEventManager()
+        .fireAndForget(new PlayerEnteredConfigurationEvent(player, serverConnection));
     if (serverConnection != null) {
       MinecraftConnection smc = serverConnection.ensureConnected();
       CompletableFuture.runAsync(() -> {
@@ -589,7 +571,7 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
 
     // Tell the server about the proxy's plugin message channels.
     ProtocolVersion serverVersion = serverMc.getProtocolVersion();
-    final Collection<String> channels = server.getChannelRegistrar()
+    final Collection<ChannelIdentifier> channels = server.getChannelRegistrar()
         .getChannelsForProtocol(serverMc.getProtocolVersion());
     if (!channels.isEmpty()) {
       serverMc.delayedWrite(constructChannelsPacket(serverVersion, channels));

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java

@@ -145,7 +145,7 @@ import org.jetbrains.annotations.NotNull;
 public class ConnectedPlayer implements MinecraftConnectionAssociation, Player, KeyIdentifiable,
     VelocityInboundConnection {
 
-  private static final int MAX_CLIENTSIDE_PLUGIN_CHANNELS = 1024;
+  public static final int MAX_CLIENTSIDE_PLUGIN_CHANNELS = 1024;
   private static final PlainTextComponentSerializer PASS_THRU_TRANSLATE =
       PlainTextComponentSerializer.builder().flattener(TranslatableMapper.FLATTENER).build();
   static final PermissionProvider DEFAULT_PERMISSIONS = s -> PermissionFunction.ALWAYS_UNDEFINED;
@@ -175,7 +175,7 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
   private final InternalTabList tabList;
   private final VelocityServer server;
   private ClientConnectionPhase connectionPhase;
-  private final Collection<String> clientsideChannels;
+  private final Collection<ChannelIdentifier> clientsideChannels;
   private final CompletableFuture<Void> teardownFuture = new CompletableFuture<>();
   private @MonotonicNonNull List<String> serversToTry = null;
   private final ResourcePackHandler resourcePackHandler;
@@ -1318,6 +1318,7 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
             connection.write(BundleDelimiterPacket.INSTANCE);
           }
           connection.write(StartUpdatePacket.INSTANCE);
+          connection.pendingConfigurationSwitch = true;
           connection.getChannel().pipeline().get(MinecraftEncoder.class).setState(StateRegistry.CONFIG);
           // Make sure we don't send any play packets to the player after update start
           connection.addPlayPacketQueueHandler();
@@ -1351,7 +1352,7 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player,
    *
    * @return the channels
    */
-  public Collection<String> getClientsideChannels() {
+  public Collection<ChannelIdentifier> getClientsideChannels() {
     return clientsideChannels;
   }
 

proxy/src/main/java/com/velocitypowered/proxy/protocol/StateRegistry.java

@@ -87,6 +87,7 @@ import com.velocitypowered.proxy.protocol.packet.StatusResponsePacket;
 import com.velocitypowered.proxy.protocol.packet.TabCompleteRequestPacket;
 import com.velocitypowered.proxy.protocol.packet.TabCompleteResponsePacket;
 import com.velocitypowered.proxy.protocol.packet.TransferPacket;
+import com.velocitypowered.proxy.protocol.packet.UpdateTeamsPacket;
 import com.velocitypowered.proxy.protocol.packet.UpsertPlayerInfoPacket;
 import com.velocitypowered.proxy.protocol.packet.chat.ChatAcknowledgementPacket;
 import com.velocitypowered.proxy.protocol.packet.chat.PlayerChatCompletionPacket;
@@ -731,6 +732,22 @@ public enum StateRegistry {
           ClientboundServerLinksPacket::new,
           map(0x7B, MINECRAFT_1_21, false),
           map(0x82, MINECRAFT_1_21_2, false));
+      clientbound.register(UpdateTeamsPacket.class, UpdateTeamsPacket::new,
+              map(0x41, ProtocolVersion.MINECRAFT_1_9, true),
+              map(0x43, ProtocolVersion.MINECRAFT_1_12, true),
+              map(0x44, ProtocolVersion.MINECRAFT_1_12_1, true),
+              map(0x47, ProtocolVersion.MINECRAFT_1_13, true),
+              map(0x4B, ProtocolVersion.MINECRAFT_1_14, true),
+              map(0x4C, ProtocolVersion.MINECRAFT_1_15, true),
+              map(0x55, ProtocolVersion.MINECRAFT_1_17, true),
+              map(0x58, ProtocolVersion.MINECRAFT_1_19_1, true),
+              map(0x56, ProtocolVersion.MINECRAFT_1_19_3, true),
+              map(0x5A, ProtocolVersion.MINECRAFT_1_19_4, true),
+              map(0x5C, ProtocolVersion.MINECRAFT_1_20_2, true),
+              map(0x5E, ProtocolVersion.MINECRAFT_1_20_3, true),
+              map(0x60, ProtocolVersion.MINECRAFT_1_20_5, true),
+              map(0x67, ProtocolVersion.MINECRAFT_1_21_2, true)
+      );
     }
   },
   LOGIN {

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/UpdateTeamsPacket.java

@@ -0,0 +1,233 @@
+/*
+ *   This file is a part of the SteamWar software.
+ *
+ *   Copyright (C) 2024  SteamWar.de-Serverteam
+ *
+ *   This program is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU Affero General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *   GNU Affero General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Affero General Public License
+ *   along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package com.velocitypowered.proxy.protocol.packet;
+
+import com.velocitypowered.api.network.ProtocolVersion;
+import com.velocitypowered.api.proxy.Player;
+import com.velocitypowered.proxy.connection.MinecraftSessionHandler;
+import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import com.velocitypowered.proxy.protocol.packet.chat.ComponentHolder;
+import io.netty.buffer.ByteBuf;
+import net.kyori.adventure.text.Component;
+
+import java.util.List;
+
+public class UpdateTeamsPacket implements MinecraftPacket {
+    private String name;
+    private Mode mode;
+
+    private Component displayName;
+    private Component prefix;
+    private Component suffix;
+    private NameTagVisibility nameTagVisibility;
+    private CollisionRule collisionRule;
+    private int color;
+    private byte friendlyFlags;
+
+    private List<String> players;
+
+    public UpdateTeamsPacket(String name, Mode mode, Component displayName, Component prefix, Component suffix, NameTagVisibility nameTagVisibility, CollisionRule collisionRule, int color, byte friendlyFlags, List<String> players) {
+        this.name = name;
+        this.mode = mode;
+        this.displayName = displayName;
+        this.prefix = prefix;
+        this.suffix = suffix;
+        this.nameTagVisibility = nameTagVisibility;
+        this.collisionRule = collisionRule;
+        this.color = color;
+        this.friendlyFlags = friendlyFlags;
+        this.players = players;
+    }
+
+    public UpdateTeamsPacket() {
+    }
+
+    @Override
+    public void decode(ByteBuf byteBuf, ProtocolUtils.Direction direction, ProtocolVersion protocolVersion) {
+        throw new UnsupportedOperationException("Packet is not implemented");
+    }
+
+    @Override
+    public boolean handle(MinecraftSessionHandler minecraftSessionHandler) {
+        return false;
+    }
+
+    @Override
+    public void encode(ByteBuf byteBuf, ProtocolUtils.Direction direction, ProtocolVersion protocolVersion) {
+        ProtocolUtils.writeString(byteBuf, name);
+        byteBuf.writeByte(mode.ordinal());
+
+        switch (mode) {
+            case CREATE, UPDATE:
+                new ComponentHolder(protocolVersion, displayName).write(byteBuf);
+                if (protocolVersion.lessThan(ProtocolVersion.MINECRAFT_1_13)) {
+                    new ComponentHolder(protocolVersion, prefix).write(byteBuf);
+                    new ComponentHolder(protocolVersion, suffix).write(byteBuf);
+                }
+                byteBuf.writeByte(friendlyFlags);
+                ProtocolUtils.writeString(byteBuf, nameTagVisibility.getValue());
+                ProtocolUtils.writeString(byteBuf, collisionRule.getValue());
+                if (protocolVersion.greaterThan(ProtocolVersion.MINECRAFT_1_12_2)) {
+                    ProtocolUtils.writeVarInt(byteBuf, color);
+                    new ComponentHolder(protocolVersion, prefix).write(byteBuf);
+                    new ComponentHolder(protocolVersion, suffix).write(byteBuf);
+                } else {
+                    byteBuf.writeByte((byte) color);
+                }
+
+                ProtocolUtils.writeVarInt(byteBuf, players.size());
+                for (String player : players) {
+                    ProtocolUtils.writeString(byteBuf, player);
+                }
+                break;
+            case ADD_PLAYER, REMOVE_PLAYER:
+                ProtocolUtils.writeVarInt(byteBuf, players.size());
+                for (String player : players) {
+                    ProtocolUtils.writeString(byteBuf, player);
+                }
+                break;
+            case REMOVE:
+                break;
+        }
+    }
+
+    public enum Mode {
+        CREATE,
+        REMOVE,
+        UPDATE,
+        ADD_PLAYER,
+        REMOVE_PLAYER,
+    }
+
+    public enum NameTagVisibility {
+        ALWAYS("always"),
+        NEVER("never"),
+        HIDE_FOR_OTHER_TEAMS("hideForOtherTeams"),
+        HIDE_FOR_OWN_TEAM("hideForOwnTeam");
+
+        private final String value;
+
+        NameTagVisibility(String value) {
+            this.value = value;
+        }
+
+        public String getValue() {
+            return value;
+        }
+    }
+
+    public enum CollisionRule {
+        ALWAYS("always"),
+        NEVER("never"),
+        PUSH_OTHER_TEAMS("pushOtherTeams"),
+        PUSH_OWN_TEAM("pushOwnTeam");
+
+        private final String value;
+
+        CollisionRule(String value) {
+            this.value = value;
+        }
+
+        public String getValue() {
+            return value;
+        }
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public Mode getMode() {
+        return mode;
+    }
+
+    public Component getDisplayName() {
+        return displayName;
+    }
+
+    public Component getPrefix() {
+        return prefix;
+    }
+
+    public Component getSuffix() {
+        return suffix;
+    }
+
+    public NameTagVisibility getNameTagVisibility() {
+        return nameTagVisibility;
+    }
+
+    public CollisionRule getCollisionRule() {
+        return collisionRule;
+    }
+
+    public int getColor() {
+        return color;
+    }
+
+    public byte getFriendlyFlags() {
+        return friendlyFlags;
+    }
+
+    public List<String> getPlayers() {
+        return players;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public void setMode(Mode mode) {
+        this.mode = mode;
+    }
+
+    public void setDisplayName(Component displayName) {
+        this.displayName = displayName;
+    }
+
+    public void setPrefix(Component prefix) {
+        this.prefix = prefix;
+    }
+
+    public void setSuffix(Component suffix) {
+        this.suffix = suffix;
+    }
+
+    public void setNameTagVisibility(NameTagVisibility nameTagVisibility) {
+        this.nameTagVisibility = nameTagVisibility;
+    }
+
+    public void setCollisionRule(CollisionRule collisionRule) {
+        this.collisionRule = collisionRule;
+    }
+
+    public void setColor(int color) {
+        this.color = color;
+    }
+
+    public void setFriendlyFlags(byte friendlyFlags) {
+        this.friendlyFlags = friendlyFlags;
+    }
+
+    public void setPlayers(List<String> players) {
+        this.players = players;
+    }
+}

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/chat/keyed/KeyedPlayerChatPacket.java

@@ -116,6 +116,8 @@ public class KeyedPlayerChatPacket implements MinecraftPacket {
             ProtocolUtils.readByteArray(buf));
       }
     }
+
+    unsigned = true;
   }
 
   @Override

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/chat/keyed/KeyedPlayerCommandPacket.java

@@ -132,6 +132,7 @@ public class KeyedPlayerCommandPacket implements MinecraftPacket {
       unsigned = true;
     }
 
+    unsigned = true;
   }
 
   @Override

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/chat/session/SessionPlayerChatPacket.java

@@ -69,6 +69,7 @@ public class SessionPlayerChatPacket implements MinecraftPacket {
     this.salt = buf.readLong();
     this.signed = buf.readBoolean();
     if (this.signed) {
+      this.signed = false;
       this.signature = readMessageSignature(buf);
     } else {
       this.signature = new byte[0];

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/chat/session/SessionPlayerCommandPacket.java

@@ -46,6 +46,8 @@ public class SessionPlayerCommandPacket implements MinecraftPacket {
     this.salt = buf.readLong();
     this.argumentSignatures = new ArgumentSignatures(buf);
     this.lastSeenMessages = new LastSeenMessages(buf, protocolVersion);
+
+    this.argumentSignatures = new ArgumentSignatures();
   }
 
   @Override

proxy/src/main/java/com/velocitypowered/proxy/protocol/util/PluginMessageUtil.java

@@ -22,13 +22,20 @@ import static com.google.common.base.Preconditions.checkNotNull;
 
 import com.google.common.collect.ImmutableList;
 import com.velocitypowered.api.network.ProtocolVersion;
+import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
+import com.velocitypowered.api.proxy.messages.LegacyChannelIdentifier;
+import com.velocitypowered.api.proxy.messages.MinecraftChannelIdentifier;
 import com.velocitypowered.api.util.ProxyVersion;
+import com.velocitypowered.proxy.connection.client.ConnectedPlayer;
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import com.velocitypowered.proxy.protocol.netty.MinecraftDecoder;
 import com.velocitypowered.proxy.protocol.packet.PluginMessagePacket;
+import com.velocitypowered.proxy.util.except.QuietDecoderException;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
 import java.nio.charset.StandardCharsets;
 import java.util.Collection;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Locale;
 import java.util.regex.Pattern;
@@ -85,13 +92,18 @@ public final class PluginMessageUtil {
         .equals(UNREGISTER_CHANNEL);
   }
 
+  private static final QuietDecoderException ILLEGAL_CHANNEL = new QuietDecoderException("Illegal channel");
+
   /**
    * Fetches all the channels in a register or unregister plugin message.
    *
+   * @param existingChannels the number of channels already registered
    * @param message the message to get the channels from
    * @return the channels, as an immutable list
    */
-  public static List<String> getChannels(PluginMessagePacket message) {
+  public static List<ChannelIdentifier> getChannels(int existingChannels,
+                                                    PluginMessagePacket message,
+                                                    ProtocolVersion protocolVersion) {
     checkNotNull(message, "message");
     checkArgument(isRegister(message) || isUnregister(message), "Unknown channel type %s",
         message.getChannel());
@@ -100,8 +112,28 @@ public final class PluginMessageUtil {
       // has caused issues with 1.13+ compatibility. Just return an empty list.
       return ImmutableList.of();
     }
-    String channels = message.content().toString(StandardCharsets.UTF_8);
-    return ImmutableList.copyOf(channels.split("\0"));
+    String payload = message.content().toString(StandardCharsets.UTF_8);
+    checkArgument(payload.length() <= Short.MAX_VALUE, "payload too long: %s", payload.length());
+    String[] channels = payload.split("\0");
+    checkArgument(existingChannels + channels.length <= ConnectedPlayer.MAX_CLIENTSIDE_PLUGIN_CHANNELS,
+        "too many channels: %s + %s > %s", existingChannels, channels.length, ConnectedPlayer.MAX_CLIENTSIDE_PLUGIN_CHANNELS);
+    ImmutableList.Builder<ChannelIdentifier> channelIdentifiers = ImmutableList.builderWithExpectedSize(channels.length);
+    try {
+      for (String channel : channels) {
+        if (protocolVersion.noLessThan(ProtocolVersion.MINECRAFT_1_13)) {
+          channelIdentifiers.add(MinecraftChannelIdentifier.from(channel));
+        } else {
+          channelIdentifiers.add(new LegacyChannelIdentifier(channel));
+        }
+      }
+    } catch (IllegalArgumentException e) {
+      if (MinecraftDecoder.DEBUG) {
+        throw e;
+      } else {
+        throw ILLEGAL_CHANNEL;
+      }
+    }
+    return channelIdentifiers.build();
   }
 
   /**
@@ -112,16 +144,31 @@ public final class PluginMessageUtil {
    * @return the plugin message to send
    */
   public static PluginMessagePacket constructChannelsPacket(ProtocolVersion protocolVersion,
-                                                            Collection<String> channels) {
+                                                            Collection<ChannelIdentifier> channels) {
     checkNotNull(channels, "channels");
     checkArgument(!channels.isEmpty(), "no channels specified");
     String channelName = protocolVersion.noLessThan(ProtocolVersion.MINECRAFT_1_13)
         ? REGISTER_CHANNEL : REGISTER_CHANNEL_LEGACY;
     ByteBuf contents = Unpooled.buffer();
-    contents.writeCharSequence(String.join("\0", channels), StandardCharsets.UTF_8);
+    contents.writeCharSequence(joinChannels(channels), StandardCharsets.UTF_8);
     return new PluginMessagePacket(channelName, contents);
   }
 
+  private static String joinChannels(Collection<ChannelIdentifier> channels) {
+    checkNotNull(channels, "channels");
+    checkArgument(!channels.isEmpty(), "no channels specified");
+    StringBuilder sb = new StringBuilder();
+    Iterator<ChannelIdentifier> iterator = channels.iterator();
+    while (iterator.hasNext()) {
+      ChannelIdentifier channel = iterator.next();
+      sb.append(channel.getId());
+      if (iterator.hasNext()) {
+        sb.append('\0');
+      }
+    }
+    return sb.toString();
+  }
+
   /**
    * Rewrites the brand message to indicate the presence of Velocity.
    *

proxy/src/main/java/com/velocitypowered/proxy/util/VelocityChannelRegistrar.java

@@ -79,10 +79,10 @@ public class VelocityChannelRegistrar implements ChannelRegistrar {
    *
    * @return all legacy channel IDs
    */
-  public Collection<String> getLegacyChannelIds() {
-    Collection<String> ids = new HashSet<>();
+  public Collection<ChannelIdentifier> getLegacyChannelIds() {
+    Collection<ChannelIdentifier> ids = new HashSet<>();
     for (ChannelIdentifier value : identifierMap.values()) {
-      ids.add(value.getId());
+      ids.add(new LegacyChannelIdentifier(value.getId()));
     }
     return ids;
   }
@@ -92,13 +92,13 @@ public class VelocityChannelRegistrar implements ChannelRegistrar {
    *
    * @return the channel IDs for Minecraft 1.13 and above
    */
-  public Collection<String> getModernChannelIds() {
-    Collection<String> ids = new HashSet<>();
+  public Collection<ChannelIdentifier> getModernChannelIds() {
+    Collection<ChannelIdentifier> ids = new HashSet<>();
     for (ChannelIdentifier value : identifierMap.values()) {
       if (value instanceof MinecraftChannelIdentifier) {
-        ids.add(value.getId());
+        ids.add(value);
       } else {
-        ids.add(PluginMessageUtil.transformLegacyToModernChannel(value.getId()));
+        ids.add(MinecraftChannelIdentifier.from(PluginMessageUtil.transformLegacyToModernChannel(value.getId())));
       }
     }
     return ids;
@@ -114,7 +114,7 @@ public class VelocityChannelRegistrar implements ChannelRegistrar {
    * @param protocolVersion the protocol version in use
    * @return the list of channels to register
    */
-  public Collection<String> getChannelsForProtocol(ProtocolVersion protocolVersion) {
+  public Collection<ChannelIdentifier> getChannelsForProtocol(ProtocolVersion protocolVersion) {
     if (protocolVersion.noLessThan(ProtocolVersion.MINECRAFT_1_13)) {
       return getModernChannelIds();
     }

proxy/src/test/java/com/velocitypowered/proxy/util/VelocityChannelRegistrarTest.java

@@ -20,8 +20,10 @@ package com.velocitypowered.proxy.util;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import com.google.common.collect.ImmutableSet;
+import com.velocitypowered.api.proxy.messages.ChannelIdentifier;
 import com.velocitypowered.api.proxy.messages.LegacyChannelIdentifier;
 import com.velocitypowered.api.proxy.messages.MinecraftChannelIdentifier;
+import java.util.stream.Collectors;
 import org.junit.jupiter.api.Test;
 
 class VelocityChannelRegistrarTest {
@@ -46,9 +48,9 @@ class VelocityChannelRegistrarTest {
     // Two channels cover the modern channel (velocity:test) and the legacy-mapped channel
     // (legacy:velocitytest). Make sure they're what we expect.
     assertEquals(ImmutableSet.of(MODERN.getId(), SIMPLE_LEGACY_REMAPPED), registrar
-        .getModernChannelIds());
+        .getModernChannelIds().stream().map(ChannelIdentifier::getId).collect(Collectors.toSet()));
     assertEquals(ImmutableSet.of(SIMPLE_LEGACY.getId(), MODERN.getId()), registrar
-        .getLegacyChannelIds());
+        .getLegacyChannelIds().stream().map(ChannelIdentifier::getId).collect(Collectors.toSet()));
   }
 
   @Test
@@ -57,9 +59,10 @@ class VelocityChannelRegistrarTest {
     registrar.register(SPECIAL_REMAP_LEGACY, MODERN_SPECIAL_REMAP);
 
     // This one, just one channel for the modern case.
-    assertEquals(ImmutableSet.of(MODERN_SPECIAL_REMAP.getId()), registrar.getModernChannelIds());
+    assertEquals(ImmutableSet.of(MODERN_SPECIAL_REMAP.getId()),
+        registrar.getModernChannelIds().stream().map(ChannelIdentifier::getId).collect(Collectors.toSet()));
     assertEquals(ImmutableSet.of(MODERN_SPECIAL_REMAP.getId(), SPECIAL_REMAP_LEGACY.getId()),
-        registrar.getLegacyChannelIds());
+        registrar.getLegacyChannelIds().stream().map(ChannelIdentifier::getId).collect(Collectors.toSet()));
   }
 
   @Test
@@ -68,7 +71,9 @@ class VelocityChannelRegistrarTest {
     registrar.register(MODERN, SIMPLE_LEGACY);
     registrar.unregister(SIMPLE_LEGACY);
 
-    assertEquals(ImmutableSet.of(MODERN.getId()), registrar.getModernChannelIds());
-    assertEquals(ImmutableSet.of(MODERN.getId()), registrar.getLegacyChannelIds());
+    assertEquals(ImmutableSet.of(MODERN.getId()),
+        registrar.getModernChannelIds().stream().map(ChannelIdentifier::getId).collect(Collectors.toSet()));;
+    assertEquals(ImmutableSet.of(MODERN.getId()),
+        registrar.getLegacyChannelIds().stream().map(ChannelIdentifier::getId).collect(Collectors.toSet()));
   }
 }

steamwarci.yml

@@ -0,0 +1,9 @@
+build:
+  - "./gradlew build -x check -x javadoc --no-daemon"
+
+
+artifacts:
+  "/jars/Velocity.jar": "proxy/build/libs/velocity-proxy-3.4.0-SNAPSHOT-all.jar"
+
+release:
+  - "mvn deploy:deploy-file -DgroupId=de.steamwar -DartifactId=velocity -Dversion=RELEASE -Dpackaging=jar -Dfile=/jars/Velocity.jar -Durl=file:///var/www/maven/"