feat: 添加UDP处理功能，优化DNS查询逻辑

Author: cmliu

_worker.js

@@ -294,14 +294,16 @@ async function 维列斯OverWSHandler(request) {
         value: null,
     };
     // 标记是否为 DNS 查询
+    let udpStreamWrite = null;
     let isDns = false;
 
     // WebSocket 数据流向远程服务器的管道
     readableWebSocketStream.pipeTo(new WritableStream({
         async write(chunk, controller) {
-            if (isDns) {
+            if (isDns && udpStreamWrite) {
                 // 如果是 DNS 查询，调用 DNS 处理函数
-                return await handleDNSQuery(chunk, webSocket, null, log);
+                //return await handleDNSQuery(chunk, webSocket, null, log);
+                return udpStreamWrite(chunk);
             }
             if (remoteSocketWapper.value) {
                 // 如果已有远程 Socket，直接写入数据
@@ -346,7 +348,11 @@ async function 维列斯OverWSHandler(request) {
 
             if (isDns) {
                 // 如果是 DNS 查询，调用 DNS 处理函数
-                return handleDNSQuery(rawClientData, webSocket, 维列斯ResponseHeader, log);
+                //return handleDNSQuery(rawClientData, webSocket, 维列斯ResponseHeader, log);
+                const { write } = await handleUDPOutBound(webSocket, 维列斯ResponseHeader, log);
+                udpStreamWrite = write;
+                udpStreamWrite(rawClientData);
+                return;
             }
             // 处理 TCP 出站连接
             if (!banHosts.includes(addressRemote)) {
@@ -875,6 +881,78 @@ function stringify(arr, offset = 0) {
     return uuid;
 }
 
+/**
+ * 
+ * @param {import("@cloudflare/workers-types").WebSocket} webSocket 
+ * @param {ArrayBuffer} 维列斯ResponseHeader 
+ * @param {(string)=> void} log 
+ */
+async function handleUDPOutBound(webSocket, 维列斯ResponseHeader, log) {
+
+    let is维列斯HeaderSent = false;
+    const transformStream = new TransformStream({
+        start(controller) {
+
+        },
+        transform(chunk, controller) {
+            // udp message 2 byte is the the length of udp data
+            // TODO: this should have bug, beacsue maybe udp chunk can be in two websocket message
+            for (let index = 0; index < chunk.byteLength;) {
+                const lengthBuffer = chunk.slice(index, index + 2);
+                const udpPakcetLength = new DataView(lengthBuffer).getUint16(0);
+                const udpData = new Uint8Array(
+                    chunk.slice(index + 2, index + 2 + udpPakcetLength)
+                );
+                index = index + 2 + udpPakcetLength;
+                controller.enqueue(udpData);
+            }
+        },
+        flush(controller) {
+        }
+    });
+
+    // only handle dns udp for now
+    transformStream.readable.pipeTo(new WritableStream({
+        async write(chunk) {
+            const resp = await fetch('https://1.1.1.1/dns-query',
+                {
+                    method: 'POST',
+                    headers: {
+                        'content-type': 'application/dns-message',
+                    },
+                    body: chunk,
+                })
+            const dnsQueryResult = await resp.arrayBuffer();
+            const udpSize = dnsQueryResult.byteLength;
+            // console.log([...new Uint8Array(dnsQueryResult)].map((x) => x.toString(16)));
+            const udpSizeBuffer = new Uint8Array([(udpSize >> 8) & 0xff, udpSize & 0xff]);
+            if (webSocket.readyState === WS_READY_STATE_OPEN) {
+                log(`doh success and dns message length is ${udpSize}`);
+                if (is维列斯HeaderSent) {
+                    webSocket.send(await new Blob([udpSizeBuffer, dnsQueryResult]).arrayBuffer());
+                } else {
+                    webSocket.send(await new Blob([维列斯ResponseHeader, udpSizeBuffer, dnsQueryResult]).arrayBuffer());
+                    is维列斯HeaderSent = true;
+                }
+            }
+        }
+    })).catch((error) => {
+        log('dns udp has error' + error)
+    });
+
+    const writer = transformStream.writable.getWriter();
+
+    return {
+        /**
+         * 
+         * @param {Uint8Array} chunk 
+         */
+        write(chunk) {
+            writer.write(chunk);
+        }
+    };
+}
+
 /**
  * 处理 DNS 查询的函数
  * @param {ArrayBuffer} udpChunk - 客户端发送的 DNS 查询数据
@@ -2409,7 +2487,7 @@ async function resolveToIPv6(target) {
 
     // 获取域名的IPv4地址
     async function fetchIPv4(domain) {
-        const url = `https://cloudflare-dns.com/dns-query?name=${domain}&type=A`;
+        const url = `https://1.1.1.1/dns-query?name=${domain}&type=A`;
         const response = await fetch(url, {
             headers: { 'Accept': 'application/dns-json' }
         });
@@ -2599,7 +2677,7 @@ async function bestIP(request, env, txt = 'ADD.txt') {
                     'Accept': 'application/dns-json'
                 }
             });
-            
+
             if (response.ok) {
                 const data = await response.json();
                 if (data.Status === 0 && data.Answer && data.Answer.length > 0) {