fix: stop killing NM's dnsmasq - use dnsmasq-shared.d instead

Killing all dnsmasq processes caused NetworkManager to detect its
hotspot dnsmasq died and tear down the hotspot (AP appears briefly
then disappears).

Now leverage NM's built-in dnsmasq-shared.d config directory:
write DNS hijack config before starting AP so NM's own dnsmasq
picks it up. No separate dnsmasq process needed.

Made-with: Cursor

lib/dns-hijack.js

@@ -1,112 +1,61 @@
 'use strict';
 
-const { spawn, execSync } = require('child_process');
-const fs  = require('fs');
-const os  = require('os');
+const fs   = require('fs');
 const path = require('path');
-const log = require('./logger');
-const { Watchdog } = require('./watchdog');
+const log  = require('./logger');
 
-const CONFIG_DIR = process.env.CLAWD_CONFIG_DIR
-  || (process.getuid && process.getuid() === 0 ? '/etc/clawd' : path.join(os.homedir(), '.clawd'));
-
-const DNSMASQ_CONF = path.join(CONFIG_DIR, 'dnsmasq-captive.conf');
 const CAPTIVE_DOMAIN = 'ap.cutos.ai';
 
+// NetworkManager 的 dnsmasq 共享配置目录
+// NM 启动热点时会自动加载此目录下的 .conf 文件
+const NM_DNSMASQ_DIR  = '/etc/NetworkManager/dnsmasq-shared.d';
+const CAPTIVE_CONF    = path.join(NM_DNSMASQ_DIR, 'clawd-captive.conf');
+
 /**
- * 管理 dnsmasq 进程：
- *   - 所有 DNS 查询 → 网关 IP（触发 Captive Portal 弹窗）
- *   - DHCP 分配 10.42.0.50 ~ 10.42.0.150
- *   - ap.cutos.ai 专门指向网关
+ * 通过 NetworkManager 的 dnsmasq 配置实现 DNS 劫持。
+ *
+ * NM 在创建热点时自动启动 dnsmasq 并加载 dnsmasq-shared.d/ 下的配置。
+ * 我们只需在启动热点前写入 address=/#/gatewayIp，NM 的 dnsmasq 就会
+ * 把所有域名解析到网关 IP，触发 Captive Portal 检测。
+ *
+ * 不再自行管理 dnsmasq 进程，避免与 NM 冲突导致热点被拆除。
  */
 class DnsHijack {
   constructor() {
-    this._watchdog = null;
+    this._active = false;
   }
 
   /**
-   * 启动 dnsmasq
-   * @param {string} iface - AP 接口名（如 wlan0）
+   * 写入 DNS 劫持配置（需在 startAP 之前调用）
+   * @param {string} _iface - 接口名（保留参数，兼容调用）
    * @param {string} gatewayIp - 网关 IP（如 10.42.0.1）
    */
-  start(iface, gatewayIp) {
+  start(_iface, gatewayIp) {
     this.stop();
 
-    const rangeStart = gatewayIp.replace(/\.\d+$/, '.50');
-    const rangeEnd   = gatewayIp.replace(/\.\d+$/, '.150');
-
     const conf = [
-      `interface=${iface}`,
-      'bind-interfaces',
-      `listen-address=${gatewayIp}`,
-      '',
-      '# DHCP',
-      `dhcp-range=${rangeStart},${rangeEnd},255.255.255.0,12h`,
-      `dhcp-option=3,${gatewayIp}`,   // gateway
-      `dhcp-option=6,${gatewayIp}`,   // DNS server
-      '',
-      '# DNS: 所有域名指向网关（触发 Captive Portal 检测）',
+      `# clawd captive portal DNS hijack`,
+      `# All DNS queries resolve to gateway to trigger captive portal`,
       `address=/#/${gatewayIp}`,
-      '',
-      '# 日志',
-      'log-queries',
-      'log-facility=-',  // stdout → Watchdog 采集
-      '',
-      '# 禁用系统 resolv.conf',
-      'no-resolv',
-      'no-poll',
     ].join('\n');
 
-    fs.mkdirSync(CONFIG_DIR, { recursive: true });
-    fs.writeFileSync(DNSMASQ_CONF, conf, 'utf8');
-    log.info('dns', `dnsmasq 配置已写入: ${DNSMASQ_CONF}`);
-
-    // 终止所有 dnsmasq（包括 NetworkManager 自动启动的）
-    try { execSync('pkill -9 dnsmasq', { timeout: 3000 }); } catch (_) {}
-    // 等待端口释放
-    try { execSync('sleep 1'); } catch (_) {}
-
-    // 查找 dnsmasq 二进制（/usr/sbin 可能不在普通用户 PATH 中）
-    const dnsmasqBin = findBin('dnsmasq');
-    if (!dnsmasqBin) {
-      log.error('dns', 'dnsmasq 未安装，请运行: apt install dnsmasq');
-      return;
+    try {
+      fs.mkdirSync(NM_DNSMASQ_DIR, { recursive: true });
+      fs.writeFileSync(CAPTIVE_CONF, conf, 'utf8');
+      this._active = true;
+      log.info('dns', `DNS 劫持配置已写入: ${CAPTIVE_CONF} (${CAPTIVE_DOMAIN} → ${gatewayIp})`);
+    } catch (e) {
+      log.error('dns', `写入 DNS 劫持配置失败: ${e.message}`);
     }
-
-    this._watchdog = new Watchdog('dns', dnsmasqBin, [
-      '--no-daemon',
-      `--conf-file=${DNSMASQ_CONF}`,
-    ], {
-      maxRestarts:  5,
-      windowMs:     60_000,
-      restartDelay: 2_000,
-      onStdout: (line) => log.debug('dns', line),
-      onStderr: (line) => log.debug('dns', line),
-    });
-    this._watchdog.start();
-    log.info('dns', `dnsmasq 已启动: ${CAPTIVE_DOMAIN} → ${gatewayIp}, 全域劫持`);
   }
 
   stop() {
-    if (this._watchdog) {
-      this._watchdog.stop();
-      this._watchdog = null;
+    if (this._active) {
+      try { fs.unlinkSync(CAPTIVE_CONF); } catch (_) {}
+      this._active = false;
+      log.info('dns', 'DNS 劫持配置已移除');
     }
-    try { execSync('pkill -9 dnsmasq', { timeout: 3000 }); } catch (_) {}
-    try { fs.unlinkSync(DNSMASQ_CONF); } catch (_) {}
   }
 }
 
-function findBin(name) {
-  const searchPaths = ['/usr/sbin', '/usr/bin', '/sbin', '/bin', '/usr/local/sbin', '/usr/local/bin'];
-  for (const dir of searchPaths) {
-    const full = path.join(dir, name);
-    if (fs.existsSync(full)) return full;
-  }
-  // 兜底尝试 which（PATH 可能已包含）
-  try {
-    return execSync(`which ${name}`, { encoding: 'utf8', timeout: 3000 }).trim() || null;
-  } catch (_) { return null; }
-}
-
 module.exports = { DnsHijack, CAPTIVE_DOMAIN };