源码

• (github.com)

1.下载安装OpenSSL v1.1.1w

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2.下载eclipse/mosquitt源码，并使用Visual Studio 打开

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3. 修改mosquitto_payload_modification.c文件

3.1 修改插件初始化函数mosquitto_plugin_init

// mosquitto_payload_modification.c

int mosquitto_plugin_init(mosquitto_plugin_id_t *identifier, void **user_data, struct mosquitto_opt *opts, int opt_count)
{
    UNUSED(user_data);
    UNUSED(opts);
    UNUSED(opt_count);
    int err_code = MOSQ_ERR_SUCCESS;

    mosq_pid = identifier;
    mosquitto_log_printf(MOSQ_LOG_INFO, "[mosquitto_plugin_init]");
    paser_opts(opts, opt_count); // 解析配置项

    // 注册重启
    err_code = mosquitto_callback_register(mosq_pid, MOSQ_EVT_RELOAD, callback_reload, NULL, NULL);
    if (err_code != MOSQ_ERR_SUCCESS) {
        mosquitto_log_printf(MOSQ_LOG_ERR, "[mosquitto_plugin_init][register] MOSQ_EVT_RELOAD err = %d", err_code);
        return err_code;
    }
    // 注册基础验证
    err_code = mosquitto_callback_register(mosq_pid, MOSQ_EVT_BASIC_AUTH, callback_basic_auth, NULL, NULL);
    if (err_code != MOSQ_ERR_SUCCESS) {
        mosquitto_log_printf(MOSQ_LOG_ERR, "[mosquitto_plugin_init][register] MOSQ_EVT_BASIC_AUTH err = %d", err_code);
        return err_code;
    }
    // 注册ACL验证
    err_code = mosquitto_callback_register(mosq_pid, MOSQ_EVT_ACL_CHECK, callback_acl_check, NULL, NULL);
    if (err_code != MOSQ_ERR_SUCCESS) {
        mosquitto_log_printf(MOSQ_LOG_ERR, "[mosquitto_plugin_init][register] MOSQ_EVT_ACL_CHECK err = %d", err_code);
        return err_code;
    }


    return err_code;

}

• step1: 解析配置项 (这里是直接将配置项原样打印出来)
• step2: 注册MOSQ_EVT_RELOAD回调函数
• step3: 注册MOSQ_EVT_BASIC_AUTH回调函数
• step4: 注册MOSQ_EVT_ACL_CHECK回调函数

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3.2 修改插件清理函数mosquitto_plugin_cleanup

// mosquitto_payload_modification.c

int mosquitto_plugin_cleanup(void *user_data, struct mosquitto_opt *opts, int opt_count)
{
    UNUSED(user_data);
    UNUSED(opts);
    UNUSED(opt_count);
    int err_code = MOSQ_ERR_SUCCESS;
    mosquitto_log_printf(MOSQ_LOG_INFO, "[mosquitto_plugin_cleanup]");

    err_code = mosquitto_callback_unregister(mosq_pid, MOSQ_EVT_RELOAD, callback_reload, NULL);
    if (err_code != MOSQ_ERR_SUCCESS) {
        mosquitto_log_printf(MOSQ_LOG_ERR, "[mosquitto_plugin_cleanup][unregister] MOSQ_EVT_RELOAD err = %d", err_code);
    }
    err_code = mosquitto_callback_unregister(mosq_pid, MOSQ_EVT_BASIC_AUTH, callback_basic_auth, NULL);
    if (err_code != MOSQ_ERR_SUCCESS) {
        mosquitto_log_printf(MOSQ_LOG_ERR, "[mosquitto_plugin_cleanup][unregister] MOSQ_EVT_BASIC_AUTH err = %d", err_code);
    }
    err_code = mosquitto_callback_unregister(mosq_pid, MOSQ_EVT_ACL_CHECK, callback_acl_check, NULL);
    if (err_code != MOSQ_ERR_SUCCESS) {
        mosquitto_log_printf(MOSQ_LOG_ERR, "[mosquitto_plugin_cleanup][unregister] MOSQ_EVT_ACL_CHECK err = %d", err_code);
    }

    return MOSQ_ERR_SUCCESS;
}

• 这里清理函数将之前注册的函数全部取消掉

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3.3 实现callback_reload

// mosquitto_payload_modification.c

static int callback_reload(int event, void* event_data, void* userdata) {
    UNUSED(event);
    UNUSED(userdata);

    mosquitto_log_printf(MOSQ_LOG_INFO, "[callback_reload]");

    struct mosquitto_evt_reload* ed = event_data;
    paser_opts(ed->options, ed->option_count);
    return MOSQ_ERR_SUCCESS;
}

• 重启重新解析的一次配置项

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3.4 实现callback_basic_auth函数

static int callback_basic_auth(int event, void* event_data, void* userdata) {
    UNUSED(event);
    UNUSED(userdata);

    struct mosquitto_evt_basic_auth* ed = event_data;
    char* client_id = mosquitto_client_id(ed->client);
    char* client_address = mosquitto_client_address(ed->client);

    mosquitto_log_printf(MOSQ_LOG_INFO, "[callback_basic_auth] username=%s, password=%s, client_id=%s, client_address=%s", ed->username, ed->password, client_id, client_address);


    return MOSQ_ERR_SUCCESS;
}

• 客户端首次登陆时，会回调这里，来验证客户端的登录信息是否合法
• 逻辑还没有实现，所以这里打印需要验证的常用信息，然后返回SUCCESS

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3.5 实现callback_acl_check函数

static int callback_acl_check(int event, void* event_data, void* userdata) {
    UNUSED(event);
    UNUSED(userdata);

    struct mosquitto_evt_acl_check* ed = event_data;
    char* username = mosquitto_client_username(ed->client);
    char* client_id = mosquitto_client_id(ed->client);
    char* topic = ed->topic;
    int access = ed->access;
    int qos = ed->qos;
    bool retain = ed->retain;

    mosquitto_log_printf(MOSQ_LOG_INFO, "[callback_acl_check] username=%s, client_id=%s, topic=%s, access=%d, qos=%d, retain=%d", username, client_id, topic, access, qos, retain);
    
    return MOSQ_ERR_SUCCESS;
}

• 客户端需要对某个主题进行收发消息，订阅和取消订阅的回调会到这里
• access可选的操作有MOSQ_ACL_NONE,MOSQ_ACL_READ,MOSQ_ACL_WRITE,MOSQ_ACL_SUBSCRIBE,MOSQ_ACL_UNSUBSCRIBE
• 目前逻辑没有实现，只是打印一下客户端访问信息，允许所有客户端的所有操作

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4. 使用自定义插件

4.1 编译自定义插件

4.1.1 Windows

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4.1.2 ubuntu

apt-get install build-essential
apt-get install libssl-dev
apt-get install xsltproc 
cmake -B ./cmakebuild
cd ./cmakebuild/plugins/payload-modification
make

• step1: 安装gcc等编译工具
• step2: 安装openssl
• step3: 安装xsltproc
• step4: cmake 编译到cmakebuild目录
• step5: 到对应插件目录
• step6: 得到对应的插件

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4.2 修改配置文件mosquitto.conf

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5.启动查看日志

屏幕截图 2024-01-01 001614.png

• 如图启动了两个客户端所有的认证已被我们插件代理