Wpa_supplicant工作流程分析之scan(从应用层到内核)(上)

最新推荐文章于 2024-05-30 11:49:55 发布

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最新推荐文章于 2024-05-30 11:49:55 发布 · 4.3k 阅读

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CC 4.0 BY-SA版权

本文详细解析了wpa_supplicant的初始化流程，包括参数处理、结构体初始化，以及如何接收和响应上层命令。重点剖析了扫描流程，从handler注册到实际命令处理的完整路径，涉及driver接口调用和网络扫描操作。

Wpa_supplicant工作流程分析

wpa_supplicant官网：https://w1.fi/wpa_supplicant/

wpa_supplicant源码下载官网地址：https://w1.fi/releases/

本文分析基于版本：V2.6

1. 初始化

wpa_supplicant/main.c

在main()中，完成了四件事。先看一下源代码，我们再来一一分析。

int main(int argc, char *argv[])
{
   
   
	...
	//循环接收传入的参数
	for (;;) {
   
   
		c = getopt(argc, argv,
			   "b:Bc:C:D:de:f:g:G:hi:I:KLMm:No:O:p:P:qsTtuvW");
		if (c < 0)
			break;
		switch (c) {
   
   
		case 'b':
			iface->bridge_ifname = optarg;
			break;
		case 'B':
			params.daemonize++;
			break;
		case 'c':
			iface->confname = optarg;
			break;
		case 'C':
			iface->ctrl_interface = optarg;
			break;
		case 'D':
			iface->driver = optarg;
			break;
		case 'd':
#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':
			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;
	//通过传入的参数，开始进行初始化工作
	global = wpa_supplicant_init(&params);
	if (global == NULL) {
   
   
		wpa_printf(MSG_ERROR, "Failed to initialize wpa_supplicant");
		exitcode = -<