Added frontend HAProxy support

src/main/java/net/raphimc/viaproxy/protocoltranslator/viaproxy/ViaProxyConfig.java

@@ -58,6 +58,7 @@ public class ViaProxyConfig extends Config implements com.viaversion.viaversion.
     private final OptionSpec<Boolean> optionBetacraftAuth;
     private final OptionSpec<String> optionBackendProxyUrl;
     private final OptionSpec<Boolean> optionBackendHaProxy;
+    private final OptionSpec<Boolean> optionFrontendHaProxy;
     private final OptionSpec<Boolean> optionChatSigning;
     private final OptionSpec<Integer> optionCompressionThreshold;
     private final OptionSpec<Boolean> optionAllowBetaPinging;
@@ -75,6 +76,7 @@ public class ViaProxyConfig extends Config implements com.viaversion.viaversion.
     private boolean betacraftAuth = false;
     private URI backendProxyUrl = null;
     private boolean backendHaProxy = false;
+    private boolean frontendHaProxy = false;
     private boolean chatSigning = true;
     private int compressionThreshold = 256;
     private boolean allowBetaPinging = false;
@@ -97,6 +99,7 @@ public class ViaProxyConfig extends Config implements com.viaversion.viaversion.
         this.optionBetacraftAuth = this.optionParser.accepts("betacraft-auth").withRequiredArg().ofType(Boolean.class).defaultsTo(this.betacraftAuth);
         this.optionBackendProxyUrl = this.optionParser.accepts("backend-proxy-url").withRequiredArg().ofType(String.class).defaultsTo("");
         this.optionBackendHaProxy = this.optionParser.accepts("backend-haproxy").withRequiredArg().ofType(Boolean.class).defaultsTo(this.backendHaProxy);
+        this.optionFrontendHaProxy = this.optionParser.accepts("frontend-haproxy").withRequiredArg().ofType(Boolean.class).defaultsTo(this.frontendHaProxy);
         this.optionChatSigning = this.optionParser.accepts("chat-signing").withRequiredArg().ofType(Boolean.class).defaultsTo(this.chatSigning);
         this.optionCompressionThreshold = this.optionParser.accepts("compression-threshold").withRequiredArg().ofType(Integer.class).defaultsTo(this.compressionThreshold);
         this.optionAllowBetaPinging = this.optionParser.accepts("allow-beta-pinging").withRequiredArg().ofType(Boolean.class).defaultsTo(this.allowBetaPinging);
@@ -126,6 +129,7 @@ public class ViaProxyConfig extends Config implements com.viaversion.viaversion.
         this.betacraftAuth = this.getBoolean("betacraft-auth", this.betacraftAuth);
         this.backendProxyUrl = this.parseProxyUrl(this.getString("backend-proxy-url", ""));
         this.backendHaProxy = this.getBoolean("backend-haproxy", this.backendHaProxy);
+        this.frontendHaProxy = this.getBoolean("frontend-haproxy", this.frontendHaProxy);
         this.chatSigning = this.getBoolean("chat-signing", this.chatSigning);
         this.compressionThreshold = this.getInt("compression-threshold", this.compressionThreshold);
         this.allowBetaPinging = this.getBoolean("allow-beta-pinging", this.allowBetaPinging);
@@ -159,6 +163,7 @@ public class ViaProxyConfig extends Config implements com.viaversion.viaversion.
             this.betacraftAuth = options.valueOf(this.optionBetacraftAuth);
             this.backendProxyUrl = this.parseProxyUrl(options.valueOf(this.optionBackendProxyUrl));
             this.backendHaProxy = options.valueOf(this.optionBackendHaProxy);
+            this.frontendHaProxy = options.valueOf(this.optionFrontendHaProxy);
             this.chatSigning = options.valueOf(this.optionChatSigning);
             this.compressionThreshold = options.valueOf(this.optionCompressionThreshold);
             this.allowBetaPinging = options.valueOf(this.optionAllowBetaPinging);
@@ -283,6 +288,15 @@ public class ViaProxyConfig extends Config implements com.viaversion.viaversion.
         this.set("backend-haproxy", backendHaProxy);
     }
 
+    public boolean useFrontendHaProxy() {
+        return this.frontendHaProxy;
+    }
+
+    public void setFrontendHaProxy(final boolean frontendHaProxy) {
+        this.frontendHaProxy = frontendHaProxy;
+        this.set("frontend-haproxy", frontendHaProxy);
+    }
+
     public boolean shouldSignChat() {
         return this.chatSigning;
     }

src/main/java/net/raphimc/viaproxy/proxy/client2proxy/Client2ProxyChannelInitializer.java

@@ -19,6 +19,7 @@ package net.raphimc.viaproxy.proxy.client2proxy;
 
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelHandler;
+import io.netty.handler.codec.haproxy.HAProxyMessageDecoder;
 import net.raphimc.netminecraft.constants.MCPipeline;
 import net.raphimc.netminecraft.netty.connection.MinecraftChannelInitializer;
 import net.raphimc.netminecraft.packet.registry.PacketRegistryUtil;
@@ -31,6 +32,8 @@ import java.util.function.Supplier;
 
 public class Client2ProxyChannelInitializer extends MinecraftChannelInitializer {
 
+    public static final String VIAPROXY_HAPROXY_DECODER_NAME = "viaproxy-haproxy-decoder";
+    public static final String VIAPROXY_HAPROXY_HANDLER_NAME = "viaproxy-haproxy-handler";
     public static final String LEGACY_PASSTHROUGH_INITIAL_HANDLER_NAME = "legacy-passthrough-initial-handler";
 
     public Client2ProxyChannelInitializer(final Supplier<ChannelHandler> handlerSupplier) {
@@ -44,6 +47,10 @@ public class Client2ProxyChannelInitializer extends MinecraftChannelInitializer
             return;
         }
 
+        if (ViaProxy.getConfig().useFrontendHaProxy()) {
+            channel.pipeline().addLast(VIAPROXY_HAPROXY_DECODER_NAME, new HAProxyMessageDecoder());
+            channel.pipeline().addLast(VIAPROXY_HAPROXY_HANDLER_NAME, new HAProxyHandler());
+        }
         if (ViaProxy.getConfig().shouldAllowLegacyClientPassthrough()) {
             channel.pipeline().addLast(LEGACY_PASSTHROUGH_INITIAL_HANDLER_NAME, new LegacyPassthroughInitialHandler());
         }

src/main/java/net/raphimc/viaproxy/proxy/client2proxy/HAProxyHandler.java

@@ -0,0 +1,51 @@
+/*
+ * This file is part of ViaProxy - https://github.com/RaphiMC/ViaProxy
+ * Copyright (C) 2021-2024 RK_01/RaphiMC and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package net.raphimc.viaproxy.proxy.client2proxy;
+
+import io.netty.channel.AbstractChannel;
+import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.SimpleChannelInboundHandler;
+import io.netty.handler.codec.haproxy.HAProxyCommand;
+import io.netty.handler.codec.haproxy.HAProxyMessage;
+import net.lenni0451.reflect.stream.RStream;
+
+import java.net.InetSocketAddress;
+
+public class HAProxyHandler extends SimpleChannelInboundHandler<HAProxyMessage> {
+
+    @Override
+    public void channelActive(ChannelHandlerContext ctx) {
+    }
+
+    @Override
+    protected void channelRead0(ChannelHandlerContext ctx, HAProxyMessage message) throws Exception {
+        if (message.command() != HAProxyCommand.PROXY) {
+            throw new UnsupportedOperationException("Unsupported HAProxy command: " + message.command());
+        }
+        if (message.sourceAddress() != null) {
+            final InetSocketAddress sourceAddress = new InetSocketAddress(message.sourceAddress(), message.sourcePort());
+            if (ctx.channel() instanceof AbstractChannel) {
+                RStream.of(AbstractChannel.class, ctx.channel()).fields().by("remoteAddress").set(sourceAddress);
+            }
+        }
+
+        ctx.pipeline().remove(this);
+        super.channelActive(ctx);
+    }
+
+}

src/main/resources/assets/viaproxy/viaproxy.yml

@@ -36,6 +36,9 @@ backend-proxy-url: ""
 # Send HAProxy protocol messages to the target server.
 backend-haproxy: false
 #
+# Read HAProxy protocol messages from client connections.
+frontend-haproxy: false
+#
 # Enables sending signed chat messages on >= 1.19 servers.
 chat-signing: true
 #