前言：之前在（九十四） Android O 连接WiFi AP流程梳理续——连接网络 和（一百一十四） Android O 连接WiFi AP流程梳理续打了写基础，梳理到了eapol，现在继续看下。

1.eapol

百度百科是这么介绍的：

EAP是Extensible Authentication Protocol的缩写，EAPOL就是(EAP OVER LAN )基于局域网的扩展认证协议。 EAPOL是基于802.1X网络访问认证技术发展而来的。

2.流程梳理

之前看代码看到了

	if (ssid) {
		wpa_s->current_ssid = ssid;
		eapol_sm_notify_config(wpa_s->eapol, NULL, NULL);
		wpa_s->connect_without_scan =
			(ssid->mode == WPAS_MODE_MESH) ? ssid : NULL;
 
		/*
		 * Don\'t optimize next scan freqs since a new ESS has been
		 * selected.
		 */
		os_free(wpa_s->next_scan_freqs);
		wpa_s->next_scan_freqs = NULL;
	} else {
		wpa_s->connect_without_scan = NULL;
	}
 
	wpa_s->disconnected = 0;
	wpa_s->reassociate = 1;
 
	if (wpa_s->connect_without_scan ||
	    wpa_supplicant_fast_associate(wpa_s) != 1) {
		wpa_s->scan_req = NORMAL_SCAN_REQ;
		wpas_scan_reset_sched_scan(wpa_s);
		wpa_supplicant_req_scan(wpa_s, 0, disconnected ? 100000 : 0);
	}
 
	if (ssid)

先看下wpa_s->eapol是如何初始化的

2.1 eapol初始化

在wpa_supplicant.c中的 wpa_supplicant_init_iface 有这么一句

static int wpa_supplicant_init_iface(struct wpa_supplicant *wpa_s,
				     struct wpa_interface *iface)
...
	if (wpa_supplicant_init_eapol(wpa_s) < 0)
		return -1;
	wpa_sm_set_eapol(wpa_s->wpa, wpa_s->eapol);

看下具体实现

int wpa_supplicant_init_eapol(struct wpa_supplicant *wpa_s)
{
#ifdef IEEE8021X_EAPOL
	struct eapol_ctx *ctx;
	ctx = os_zalloc(sizeof(*ctx));
	if (ctx == NULL) {
		wpa_printf(MSG_ERROR, \"Failed to allocate EAPOL context.\");
		return -1;
	}

	ctx->ctx = wpa_s;
	ctx->msg_ctx = wpa_s;
	ctx->eapol_send_ctx = wpa_s;
	ctx->preauth = 0;
	ctx->eapol_done_cb = wpa_supplicant_notify_eapol_done;
	ctx->eapol_send = wpa_supplicant_eapol_send;
	ctx->set_wep_key = wpa_eapol_set_wep_key;
#ifndef CONFIG_NO_CONFIG_BLOBS
	ctx->set_config_blob = wpa_supplicant_set_config_blob;
	ctx->get_config_blob = wpa_supplicant_get_config_blob;
#endif /* CONFIG_NO_CONFIG_BLOBS */
	ctx->aborted_cached = wpa_supplicant_aborted_cached;
	ctx->opensc_engine_path = wpa_s->conf->opensc_engine_path;
	ctx->pkcs11_engine_path = wpa_s->conf->pkcs11_engine_path;
	ctx->pkcs11_module_path = wpa_s->conf->pkcs11_module_path;
	ctx->openssl_ciphers = wpa_s->conf->openssl_ciphers;
	ctx->wps = wpa_s->wps;
	ctx->eap_param_needed = wpa_supplicant_eap_param_needed;
#ifdef CONFIG_EAP_PROXY
	ctx->eap_proxy_cb = wpa_supplicant_eap_proxy_cb;
	ctx->eap_proxy_notify_sim_status =
		wpa_supplicant_eap_proxy_notify_sim_status;
#endif /* CONFIG_EAP_PROXY */
	ctx->port_cb = wpa_supplicant_port_cb;
	ctx->cb = wpa_supplicant_eapol_cb;
	ctx->cert_cb = wpa_supplicant_cert_cb;
	ctx->cert_in_cb = wpa_s->conf->cert_in_cb;
	ctx->status_cb = wpa_supplicant_status_cb;
	ctx->set_anon_id = wpa_supplicant_set_anon_id;
	ctx->cb_ctx = wpa_s;
	wpa_s->eapol = eapol_sm_init(ctx);
	if (wpa_s->eapol == NULL) {
		os_free(ctx);
		wpa_printf(MSG_ERROR, \"Failed to initialize EAPOL state \"
			   \"machines.\");
		return -1;
	}
#endif /* IEEE8021X_EAPOL */

	return 0;
}

接着看eapol_sm_init

/**
 * eapol_sm_init - Initialize EAPOL state machine
 * @ctx: Pointer to EAPOL context data; this needs to be an allocated buffer
 * and EAPOL state machine will free it in eapol_sm_deinit()
 * Returns: Pointer to the allocated EAPOL state machine or %NULL on failure
 *
 * Allocate and initialize an EAPOL state machine.
 */
struct eapol_sm *eapol_sm_init(struct eapol_ctx *ctx)
{
	struct eapol_sm *sm;
	struct eap_config conf;
	sm = os_zalloc(sizeof(*sm));
	if (sm == NULL)
		return NULL;
	sm->ctx = ctx;

	sm->portControl = Auto;

	/* Supplicant PAE state machine */
	sm->heldPeriod = 60;
	sm->startPeriod = 30;
	sm->maxStart = 3;

	/* Supplicant Backend state machine */
	sm->authPeriod = 30;

	os_memset(&conf, 0, sizeof(conf));
	conf.opensc_engine_path = ctx->opensc_engine_path;
	conf.pkcs11_engine_path = ctx->pkcs11_engine_path;
	conf.pkcs11_module_path = ctx->pkcs11_module_path;
	conf.openssl_ciphers = ctx->openssl_ciphers;
	conf.wps = ctx->wps;
	conf.cert_in_cb = ctx->cert_in_cb;

	sm->eap = eap_peer_sm_init(sm, &eapol_cb, sm->ctx->msg_ctx, &conf);
	if (sm->eap == NULL) {
		os_free(sm);
		return NULL;
	}

#ifdef CONFIG_EAP_PROXY
	sm->use_eap_proxy = FALSE;
	sm->eap_proxy = eap_proxy_init(sm, &eapol_cb, sm->ctx->msg_ctx);
	if (sm->eap_proxy == NULL) {
		wpa_printf(MSG_ERROR, \"Unable to initialize EAP Proxy\");
	}
#endif /* CONFIG_EAP_PROXY */

	/* Initialize EAPOL state machines */
	sm->force_authorized_update = TRUE;
	sm->initialize = TRUE;
	eapol_sm_step(sm);
	sm->initialize = FALSE;
	eapol_sm_step(sm);

	sm->timer_tick_enabled = 1;
	eloop_register_timeout(1, 0, eapol_port_timers_tick, NULL, sm);

	return sm;
}

再看下eapol_sm_step

/**
 * eapol_sm_step - EAPOL state machine step function
 * @sm: Pointer to EAPOL state machine allocated with eapol_sm_init()
 *
 * This function is called to notify the state machine about changed external
 * variables. It will step through the EAPOL state machines in loop to process
 * all triggered state changes.
 */
void eapol_sm_step(struct eapol_sm *sm)
{
	int i;

	/* In theory, it should be ok to run this in loop until !changed.
	 * However, it is better to use a limit on number of iterations to
	 * allow events (e.g., SIGTERM) to stop the program cleanly if the
	 * state machine were to generate a busy loop. */
	for (i = 0; i < 100; i++) {
		sm->changed = FALSE;
		SM_STEP_RUN(SUPP_PAE);
		SM_STEP_RUN(KEY_RX);
		SM_STEP_RUN(SUPP_BE);
#ifdef CONFIG_EAP_PROXY
		if (sm->use_eap_proxy) {
			/* Drive the EAP proxy state machine */
			if (eap_proxy_sm_step(sm->eap_proxy, sm->eap))
				sm->changed = TRUE;
		} else
#endif /* CONFIG_EAP_PROXY */
		if (eap_peer_sm_step(sm->eap))
			sm->changed = TRUE;
		if (!sm->changed)
			break;
	}

	if (sm->changed) {
		/* restart EAPOL state machine step from timeout call in order
		 * to allow other events to be processed. */
		eloop_cancel_timeout(eapol_sm_step_timeout, NULL, sm);
		eloop_register_timeout(0, 0, eapol_sm_step_timeout, NULL, sm);
	}

	if (sm->ctx->cb && sm->cb_status != EAPOL_CB_IN_PROGRESS) {
		enum eapol_supp_result result;
		if (sm->cb_status == EAPOL_CB_SUCCESS)
			result = EAPOL_SUPP_RESULT_SUCCESS;
		else if (eap_peer_was_failure_expected(sm->eap))
			result = EAPOL_SUPP_RESULT_EXPECTED_FAILURE;
		else
			result = EAPOL_SUPP_RESULT_FAILURE;
		sm->cb_status = EAPOL_CB_IN_PROGRESS;
		sm->ctx->cb(sm, result, sm->ctx->cb_ctx);
	}
}

2.2 连接

	if (ssid) {
		wpa_s->current_ssid = ssid;
		eapol_sm_notify_config(wpa_s->eapol, NULL, NULL);
		wpa_s->connect_without_scan =
			(ssid->mode == WPAS_MODE_MESH) ? ssid : NULL;

		/*
		 * Don\'t optimize next scan freqs since a new ESS has been
		 * selected.
		 */
		os_free(wpa_s->next_scan_freqs);
		wpa_s->next_scan_freqs = NULL;
	} else {
		wpa_s->connect_without_scan = NULL;
	}

	wpa_s->disconnected = 0;
	wpa_s->reassociate = 1;

	if (wpa_s->connect_without_scan ||
	    wpa_supplicant_fast_associate(wpa_s) != 1) {
		wpa_s->scan_req = NORMAL_SCAN_REQ;
		wpas_scan_reset_sched_scan(wpa_s);
		wpa_supplicant_req_scan(wpa_s, 0, disconnected ? 100000 : 0);
	}

	if (ssid)
		wpas_notify_network_selected(wpa_s, ssid);

eapol_supp_sm.c

/**
 * eapol_sm_notify_config - Notification of EAPOL configuration change
 * @sm: Pointer to EAPOL state machine allocated with eapol_sm_init()
 * @config: Pointer to current network EAP configuration
 * @conf: Pointer to EAPOL configuration data
 *
 * Notify EAPOL state machine that configuration has changed. config will be
 * stored as a backpointer to network configuration. This can be %NULL to clear
 * the stored pointed. conf will be copied to local EAPOL/EAP configuration
 * data. If conf is %NULL, this part of the configuration change will be
 * skipped.
 */
void eapol_sm_notify_config(struct eapol_sm *sm,
			    struct eap_peer_config *config,
			    const struct eapol_config *conf)
{
	if (sm == NULL)
		return;

	sm->config = config;
#ifdef CONFIG_EAP_PROXY
	sm->use_eap_proxy = eap_proxy_notify_config(sm->eap_proxy, config) > 0;
#endif /* CONFIG_EAP_PROXY */

	if (conf == NULL)
		return;

	sm->conf.accept_802_1x_keys = conf->accept_802_1x_keys;
	sm->conf.required_keys = conf->required_keys;
	sm->conf.fast_reauth = conf->fast_reauth;
	sm->conf.workaround = conf->workaround;
	sm->conf.wps = conf->wps;
#ifdef CONFIG_EAP_PROXY
	if (sm->use_eap_proxy) {
		/* Using EAP Proxy, so skip EAP state machine update */
		return;
	}
#endif /* CONFIG_EAP_PROXY */
	if (sm->eap) {
		eap_set_fast_reauth(sm->eap, conf->fast_reauth);
		eap_set_workaround(sm->eap, conf->workaround);
		eap_set_force_disabled(sm->eap, conf->eap_disabled);
		eap_set_external_sim(sm->eap, conf->external_sim);
	}
}

void wpas_notify_network_selected(struct wpa_supplicant *wpa_s,
				  struct wpa_ssid *ssid)
{
	if (wpa_s->p2p_mgmt)
		return;

	wpas_dbus_signal_network_selected(wpa_s, ssid->id);
}

/**
 * wpas_dbus_signal_network_selected - Send a network selected signal
 * @wpa_s: %wpa_supplicant network interface data
 * @id: network id
 *
 * Notify listeners about selecting a network
 */
void wpas_dbus_signal_network_selected(struct wpa_supplicant *wpa_s, int id)
{
	wpas_dbus_signal_network(wpa_s, id, \"NetworkSelected\", FALSE);
}

/**
 * wpas_dbus_signal_network - Send a network related event signal
 * @wpa_s: %wpa_supplicant network interface data
 * @id: new network id
 * @sig_name: signal name - NetworkAdded, NetworkRemoved or NetworkSelected
 * @properties: determines if add second argument with object properties
 *
 * Notify listeners about event related with configured network
 */
static void wpas_dbus_signal_network(struct wpa_supplicant *wpa_s,
				     int id, const char *sig_name,
				     int properties)
{
	struct wpas_dbus_priv *iface;
	DBusMessage *msg;
	DBusMessageIter iter;
	char net_obj_path[WPAS_DBUS_OBJECT_PATH_MAX], *path;

	iface = wpa_s->global->dbus;

	/* Do nothing if the control interface is not turned on */
	if (iface == NULL || !wpa_s->dbus_new_path)
		return;

	os_snprintf(net_obj_path, WPAS_DBUS_OBJECT_PATH_MAX,
		    \"%s/\" WPAS_DBUS_NEW_NETWORKS_PART \"/%u\",
		    wpa_s->dbus_new_path, id);

	msg = dbus_message_new_signal(wpa_s->dbus_new_path,
				      WPAS_DBUS_NEW_IFACE_INTERFACE,
				      sig_name);
	if (msg == NULL)
		return;

	dbus_message_iter_init_append(msg, &iter);
	path = net_obj_path;
	if (!dbus_message_iter_append_basic(&iter, DBUS_TYPE_OBJECT_PATH,
					    &path) ||
	    (properties &&
	     !wpa_dbus_get_object_properties(
		     iface, net_obj_path, WPAS_DBUS_NEW_IFACE_NETWORK,
		     &iter)))
		wpa_printf(MSG_ERROR, \"dbus: Failed to construct signal\");
	else
		dbus_connection_send(iface->con, msg, NULL);
	dbus_message_unref(msg);
}

3.总结

又回到了一脸懵逼的状态，待续。。。