Android wpa_supplicant 源码分析二 -- main()

 main()

int main(int argc, char *argv[])
{
	int c, i;
    // 重要的数据结构1 
	struct wpa_interface *ifaces, *iface;
	int iface_count, exitcode = -1;
	struct wpa_params params;
    // 重要的数据结构2
	struct wpa_global *global;

	if (os_program_init())
		return -1;

	os_memset(&params, 0, sizeof(params));
    // 设置log等级，external/wpa_supplicant_8/hostapd/src/utils/wpa_debug.c中也会设置        log等级，但是在这里会被重新修改
	params.wpa_debug_level = MSG_INFO;

	iface = ifaces = os_zalloc(sizeof(struct wpa_interface));
	if (ifaces == NULL)
		return -1;
	iface_count = 1;

    // 标准输入输出重定向到/dev/null
	wpa_supplicant_fd_workaround(1);

	for (;;) {
        // 解析启动参数
		c = getopt(argc, argv,
			   "b:Bc:C:D:de:f:g:G:hi:I:KLMm:No:O:p:P:qsTtuvW");
		if (c < 0)
			break;
        // 添加调试log,便于code分析
        wpa_printf(MSG_ERROR,"argv:\t -%c %s\n", c, optarg);
		switch (c) {
		case 'b':
			iface->bridge_ifname = optarg;
			break;
		case 'B':
			params.daemonize++;
			break;
		case 'c':
            // 指定的配置文件如：wpa_supplicant.conf
			iface->confname = optarg;
			break;
		case 'C':
			iface->ctrl_interface = optarg;
			break;
		case 'D':
            // 驱动名称如 -Dnl80211
			iface->driver = optarg;
			break;
		case 'd':
            // log 等级
#ifdef CONFIG_NO_STDOUT_DEBUG
			printf("Debugging disabled with "
			       "CONFIG_NO_STDOUT_DEBUG=y build time "
			       "option.\n");
			goto out;
#else /* CONFIG_NO_STDOUT_DEBUG */
			params.wpa_debug_level--;
			break;
#endif /* CONFIG_NO_STDOUT_DEBUG */
		case 'e':
			params.entropy_file = optarg;
			break;
#ifdef CONFIG_DEBUG_FILE
		case 'f':
			params.wpa_debug_file_path = optarg;
			break;
#endif /* CONFIG_DEBUG_FILE */
		case 'g':
			params.ctrl_interface = optarg;
			break;
		case 'G':
			params.ctrl_interface_group = optarg;
			break;
		case 'h':
			usage();
			exitcode = 0;
			goto out;
		case 'i':
            //网络接口名称
			iface->ifname = optarg;
			break;
		case 'I':
			iface->confanother = optarg;
			break;
		case 'K':
			params.wpa_debug_show_keys++;
			break;
		case 'L':
			license();
			exitcode = 0;
			goto out;
#ifdef CONFIG_P2P
		case 'm':
			params.conf_p2p_dev = optarg;
			break;
#endif /* CONFIG_P2P */
		case 'o':
			params.override_driver = optarg;
			break;
		case 'O':
			params.override_ctrl_interface = optarg;
			break;
		case 'p':
			iface->driver_param = optarg;
			break;
		case 'P':
			os_free(params.pid_file);
			params.pid_file = os_rel2abs_path(optarg);
			break;
		case 'q':
			params.wpa_debug_level++;
			break;
#ifdef CONFIG_DEBUG_SYSLOG
		case 's':
			params.wpa_debug_syslog++;
			break;
#endif /* CONFIG_DEBUG_SYSLOG */
#ifdef CONFIG_DEBUG_LINUX_TRACING
		case 'T':
			params.wpa_debug_tracing++;
			break;
#endif /* CONFIG_DEBUG_LINUX_TRACING */
		case 't':
			params.wpa_debug_timestamp++;
			break;
#ifdef CONFIG_DBUS
		case 'u':
			params.dbus_ctrl_interface = 1;
			break;
#endif /* CONFIG_DBUS */
		case 'v':
			printf("%s\n", wpa_supplicant_version);
			exitcode = 0;
			goto out;
		case 'W':
			params.wait_for_monitor++;
			break;
#ifdef CONFIG_MATCH_IFACE
		case 'M':
			params.match_iface_count++;
			iface = os_realloc_array(params.match_ifaces,
						 params.match_iface_count,
						 sizeof(struct wpa_interface));
			if (!iface)
				goto out;
			params.match_ifaces = iface;
			iface = &params.match_ifaces[params.match_iface_count -
						     1];
			os_memset(iface, 0, sizeof(*iface));
			break;
#endif /* CONFIG_MATCH_IFACE */
		case 'N':
			iface_count++;
			iface = os_realloc_array(ifaces, iface_count,
						 sizeof(struct wpa_interface));
			if (iface == NULL)
				goto out;
			ifaces = iface;
			iface = &ifaces[iface_count - 1];
			os_memset(iface, 0, sizeof(*iface));
			break;
		default:
			usage();
			exitcode = 0;
			goto out;
		}
	}

	exitcode = 0;
    //主要函数1 : 创建并初始化一个global 
	global = wpa_supplicant_init(&params);
	if (global == NULL) {
		wpa_printf(MSG_ERROR, "Failed to initialize wpa_supplicant");
		exitcode = -1;
		goto out;
	} else {
		wpa_printf(MSG_INFO, "Successfully initialized "
			   "wpa_supplicant");
	}
    // 初始化 fst
	if (fst_global_init()) {
		wpa_printf(MSG_ERROR, "Failed to initialize FST");
		exitcode = -1;
		goto out;
	}

#if defined(CONFIG_FST) && defined(CONFIG_CTRL_IFACE)
	if (!fst_global_add_ctrl(fst_ctrl_cli))
		wpa_printf(MSG_WARNING, "Failed to add CLI FST ctrl");
#endif

	for (i = 0; exitcode == 0 && i < iface_count; i++) {
		struct wpa_supplicant *wpa_s;

		if ((ifaces[i].confname == NULL &&
		     ifaces[i].ctrl_interface == NULL) ||
		    ifaces[i].ifname == NULL) {
			if (iface_count == 1 && (params.ctrl_interface ||
#ifdef CONFIG_MATCH_IFACE
						 params.match_iface_count ||
#endif /* CONFIG_MATCH_IFACE */
						 params.dbus_ctrl_interface))
				break;
			usage();
			exitcode = -1;
			break;
		}
        // 主要函数2 : 支持多个无线网络设备,
		wpa_s = wpa_supplicant_add_iface(global, &ifaces[i], NULL);
		if (wpa_s == NULL) {
			exitcode = -1;
			break;
		}
	}

#ifdef CONFIG_MATCH_IFACE
	if (exitcode == 0)
		exitcode = wpa_supplicant_init_match(global);
#endif /* CONFIG_MATCH_IFACE */

    // 启动, wpa_supplicant 通过epoll 方式实现多路I/O复用
	if (exitcode == 0)
		exitcode = wpa_supplicant_run(global);

    // 退出，释放资源
	wpa_supplicant_deinit(global);

	fst_global_deinit();

out:
	wpa_supplicant_fd_workaround(0);
	os_free(ifaces);
#ifdef CONFIG_MATCH_IFACE
	os_free(params.match_ifaces);
#endif /* CONFIG_MATCH_IFACE */
	os_free(params.pid_file);

	os_program_deinit();

	return exitcode;
}

重要的数据结构1 ： wpa_interface：

每个wpa_interface对象描述一个无线网络设备，对应一个wpa_supplicant，

struct wpa_interface {
	/**
	 * confname - Configuration name (file or profile) name
	 *
	 * This can also be %NULL when a configuration file is not used. In
	 * that case, ctrl_interface must be set to allow the interface to be
	 * configured.
	 */
	const char *confname; // 配置文件名

	/**
	 * confanother - Additional configuration name (file or profile) name
	 *
	 * This can also be %NULL when the additional configuration file is not
	 * used.
	 */
	const char *confanother;

	/**
	 * ctrl_interface - Control interface parameter
	 *
	 * If a configuration file is not used, this variable can be used to
	 * set the ctrl_interface parameter that would have otherwise been read
	 * from the configuration file. If both confname and ctrl_interface are
	 * set, ctrl_interface is used to override the value from configuration
	 * file.
	 */
	const char *ctrl_interface; //控制接口路径

	/**
	 * driver - Driver interface name, or %NULL to use the default driver
	 */
	const char *driver; // 对应的驱动名

	/**
	 * driver_param - Driver interface parameters
	 *
	 * If a configuration file is not used, this variable can be used to
	 * set the driver_param parameters that would have otherwise been read
	 * from the configuration file. If both confname and driver_param are
	 * set, driver_param is used to override the value from configuration
	 * file.
	 */
	const char *driver_param;

	/**
	 * ifname - Interface name
	 */
	const char *ifname; //网络接口设备名

	/**
	 * bridge_ifname - Optional bridge interface name
	 *
	 * If the driver interface (ifname) is included in a Linux bridge
	 * device, the bridge interface may need to be used for receiving EAPOL
	 * frames. This can be enabled by setting this variable to enable
	 * receiving of EAPOL frames from an additional interface.
	 */
	const char *bridge_ifname;

	/**
	 * p2p_mgmt - Interface used for P2P management (P2P Device operations)
	 *
	 * Indicates whether wpas_p2p_init() must be called for this interface.
	 * This is used only when the driver supports a dedicated P2P Device
	 * interface that is not a network interface.
	 */
	int p2p_mgmt;
};

重要的数据结构2， wpa_global ：

wpa_global对象描述全局上下文信息

struct wpa_global {
	struct wpa_supplicant *ifaces; // 指向wpa_supplicant对象链表
	struct wpa_params params;
	struct ctrl_iface_global_priv *ctrl_iface; // 对应全局控制接口，如果设置了该接口，其他wap_interface设置的控制接口将被代替
	struct wpas_dbus_priv *dbus;
	struct wpas_binder_priv *binder;
	void **drv_priv; //  = wpa_drivers[i]->global_init()：包含driver所需要的全局上下文信息
	size_t drv_count;
	struct os_time suspend_time;
	struct p2p_data *p2p;
	struct wpa_supplicant *p2p_init_wpa_s;
	struct wpa_supplicant *p2p_group_formation;
	struct wpa_supplicant *p2p_invite_group;
	u8 p2p_dev_addr[ETH_ALEN];
	struct os_reltime p2p_go_wait_client;
	struct dl_list p2p_srv_bonjour; /* struct p2p_srv_bonjour */
	struct dl_list p2p_srv_upnp; /* struct p2p_srv_upnp */
	int p2p_disabled;
	int cross_connection;
	struct wpa_freq_range_list p2p_disallow_freq;
	struct wpa_freq_range_list p2p_go_avoid_freq;
	enum wpa_conc_pref {
		WPA_CONC_PREF_NOT_SET,
		WPA_CONC_PREF_STA,
		WPA_CONC_PREF_P2P
	} conc_pref;
	unsigned int p2p_per_sta_psk:1;
	unsigned int p2p_fail_on_wps_complete:1;
	unsigned int p2p_24ghz_social_channels:1;
	unsigned int pending_p2ps_group:1;
	unsigned int pending_group_iface_for_p2ps:1;
	unsigned int pending_p2ps_group_freq;

#ifdef CONFIG_WIFI_DISPLAY
	int wifi_display;
#define MAX_WFD_SUBELEMS 10
	struct wpabuf *wfd_subelem[MAX_WFD_SUBELEMS];
#endif /* CONFIG_WIFI_DISPLAY */

	struct psk_list_entry *add_psk; /* From group formation */
};

综上

main函数主要做了如下事情：

1. 解析启动参数

2. global = wpa_supplicant_init(&params);

3. fst_global_init()

4. wpa_s = wpa_supplicant_add_iface(global, &ifaces[i], NULL);

5. exitcode = wpa_supplicant_run(global); 

启动参数：

device/qcom/common/rootdir/etc/init.qcom.rc
service wpa_supplicant /vendor/bin/hw/wpa_supplicant \
    -O/data/vendor/wifi/wpa/sockets -puse_p2p_group_interface=1 -dd \
    -g@android:vendor_wpa_wlan0
#    we will start as root and wpa_supplicant will switch to user wifi
#    after setting up the capabilities required for WEXT
#    user wifi
#    group wifi inet keystore
    interface android.hardware.wifi.supplicant@1.0::ISupplicant default
    interface android.hardware.wifi.supplicant@1.1::ISupplicant default
    class main
    socket vendor_wpa_wlan0 dgram 660 wifi wifi
    disabled
    oneshot

启动参数log: 

 E wpa_supplicant: argv:       -O /data/vendor/wifi/wpa/sockets
 E wpa_supplicant: argv:       -p use_p2p_group_interface=1
 E wpa_supplicant: argv:       -d (null)
 E wpa_supplicant: argv:       -d (null)
 E wpa_supplicant: argv:       -g @android:vendor_wpa_wlan0