Android升级OpenWrt固件

Posted on 2018-09-22 | In Android , OpenWrt

有这么一个需求，需要通过Android升级OpenWrt的固件（Firmware）。参考OpenWrt提供的升级方案，可以使用SSH的scp命令将固件上传到路由器的/tmp目录下，然后执行命令sysupgrade -v /tmp/firmware_name.bin升级固件。

Android中使用SSH

The SSH protocol uses encryption to secure the connection between a client and a server. All user authentication, commands, output, and file transfers are encrypted to protect against attacks in the network.

站在巨人的肩膀上，不要重复造轮子。Ganymed SSH-2是一个实现了SSH-2协议的Java库，解压ganymed-ssh2-build210.zip，将里面的jar包导入自己的Android项目的libs目录下，并在Module的build.gradle文件中添加如下代码：

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    ... ...
    implementation files('libs/ganymed-ssh2-build210.jar')
}

这个时候就可以在项目中愉快地使用SSH了。

升级固件

public static boolean upgradeFirmware(String hostname, String username,String password ,String firmwarePath) {
    File firmware = new File(firmwarePath);

    try {
        /* Create a connection instance */
        Connection conn = new Connection(hostname);

        /* Now connect */
        conn.connect();

        /* Authenticate.
         * If you get an IOException saying something like
         * "Authentication method password not supported by the server at this stage."
         * then please check the FAQ.
         */
        boolean isAuthenticated = conn.authenticateWithPassword(username, password);

        if (!isAuthenticated)
            throw new IOException("Authentication failed.");

        /* Create a scp client */
        SCPClient scpClient = conn.createSCPClient();

        /* Upload firmware file to remote's /tmp */
        scpClient.put(firmware.getAbsolutePath(), "/tmp");

        /* Create a session */
        Session session = conn.openSession();

        /* Upgrade firmware */
        session.execCommand("sysupgrade -v /tmp/" + firmware.getName());

        /*
         * This basic example does not handle stderr, which is sometimes dangerous
         * (please read the FAQ).
         */
        InputStream stdout = new StreamGobbler(session.getStdout());

        BufferedReader br = new BufferedReader(new InputStreamReader(stdout));

        while (true) {
            String line = br.readLine();
            if (line == null)
                break;
            System.out.println(line);
        }

        /* Show exit status, if available (otherwise "null") */
        System.out.println("ExitCode: " + session.getExitStatus());

        /* Close this session */
        session.close();

        /* Close the connection */
        conn.close();

        return true;
    } catch (IOException e) {
        e.printStackTrace(System.err);
        
        return false;
    }
}

代码很简单，这里就不做过多解释了。但是升级固件并不一定会成功，如路由器的空间不足以存放新的固件时。

参考文档