服务端收到来自访问者的udp数据，转发到客户端

neutrino-proxy-core/src/main/java/org/dromara/neutrinoproxy/core/ProxyMessage.java

@@ -66,6 +66,10 @@ public class ProxyMessage {
      * 通用异常信息
      */
     public static final byte TYPE_ERROR = 0x06;
+    /**
+     * UDP数据传输
+     */
+    private static final byte TYPE_UDP_TRANSFER = 0x07;
 
     /**
      * 消息类型
@@ -130,6 +134,17 @@ public class ProxyMessage {
             .setData(data);
     }
 
+    public static ProxyMessage buildUdpTransferMessage(String visitorIp, int visitorPort, String targetIp, int targetPort, byte[] data) {
+        return create().setType(TYPE_UDP_TRANSFER)
+                .setInfo(JSONObject.toJSONString(new UdpBaseInfo()
+                        .setVisitorIp(visitorIp)
+                        .setVisitorPort(visitorPort)
+                        .setTargetIp(targetIp)
+                        .setTargetPort(targetPort)
+                ))
+                .setData(data);
+    }
+
     public static ProxyMessage buildErrMessage(ExceptionEnum exceptionEnum, String info) {
         JSONObject data = new JSONObject();
         data.put("code", exceptionEnum.getCode());
@@ -142,4 +157,13 @@ public class ProxyMessage {
     public static ProxyMessage buildErrMessage(ExceptionEnum exceptionEnum) {
        return buildErrMessage(exceptionEnum, null);
     }
+
+    @Accessors(chain = true)
+    @Data
+    public static class UdpBaseInfo {
+        private String visitorIp;
+        private int visitorPort;
+        private String targetIp;
+        private int targetPort;
+    }
 }

neutrino-proxy-server/src/main/java/org/dromara/neutrinoproxy/server/proxy/core/UdpVisitorChannelHandler.java

@@ -1,9 +1,15 @@
 package org.dromara.neutrinoproxy.server.proxy.core;
 
+import cn.hutool.core.util.StrUtil;
+import io.netty.channel.Channel;
 import io.netty.channel.ChannelHandlerContext;
+import io.netty.channel.ChannelOption;
 import io.netty.channel.SimpleChannelInboundHandler;
 import io.netty.channel.socket.DatagramPacket;
+import org.dromara.neutrinoproxy.core.ProxyMessage;
+import org.dromara.neutrinoproxy.server.util.ProxyUtil;
 
+import java.net.InetSocketAddress;
 import java.nio.charset.StandardCharsets;
 
 /**
@@ -13,8 +19,40 @@ import java.nio.charset.StandardCharsets;
 public class UdpVisitorChannelHandler extends SimpleChannelInboundHandler<DatagramPacket> {
 
     @Override
-    protected void channelRead0(ChannelHandlerContext channelHandlerContext, DatagramPacket datagramPacket) throws Exception {
+    protected void channelRead0(ChannelHandlerContext ctx, DatagramPacket datagramPacket) throws Exception {
         System.out.println("服务端接收到消息 \nsender:" + datagramPacket.sender().toString() + "内容\n" + datagramPacket.content().toString(StandardCharsets.UTF_8));
-    }
 
+        Channel visitorChannel = ctx.channel();
+        InetSocketAddress sa = (InetSocketAddress) visitorChannel.localAddress();
+        Channel cmdChannel = ProxyUtil.getCmdChannelByServerPort(sa.getPort());
+
+        if (null == cmdChannel) {
+            // 该端口还没有代理客户端
+            ctx.channel().close();
+            return;
+        }
+
+        // 根据代理服务端端口，获取被代理客户端局域网连接信息
+        String lanInfo = ProxyUtil.getClientLanInfoByServerPort(sa.getPort());
+        if (StrUtil.isEmpty(lanInfo)) {
+            ctx.channel().close();
+            return;
+        }
+
+        String[] targetInfo = lanInfo.split(":");
+        String targetIp = targetInfo[0];
+        int targetPort = Integer.parseInt(targetInfo[1]);
+
+        // 转发代理数据
+        byte[] bytes = new byte[datagramPacket.content().readableBytes()];
+        datagramPacket.content().readBytes(bytes);
+
+        cmdChannel.writeAndFlush(ProxyMessage.buildUdpTransferMessage(
+                sa.getAddress().getHostAddress(),
+                sa.getPort(),
+                targetIp,
+                targetPort,
+                bytes
+        ));
+    }
 }