Add framework for exclusive radio operations

The new radio work item concept can be used to request time for an
operation that requires exclusive radio control, e.g., a scan. Once the
radio is available, the registered callback function will be called.
radio_work_done() must be called once the exclusive radio operation has
been completed, so that the radio is freed for other operations. The
special case of deinit=1 is used to free the context data during
interface removal. That does not allow the callback function to start
the radio operation, i.e., it needs to free the allocated resources
and return.

Signed-hostap: Jouni Malinen <j@w1.fi>

wpa_supplicant/ctrl_iface.c

@@ -5216,6 +5216,8 @@ static void wpa_supplicant_ctrl_iface_flush(struct wpa_supplicant *wpa_s)
 	wpa_sm_set_param(wpa_s->wpa, RSNA_PMK_REAUTH_THRESHOLD, 70);
 	wpa_sm_set_param(wpa_s->wpa, RSNA_SA_TIMEOUT, 60);
 	eapol_sm_notify_logoff(wpa_s->eapol, FALSE);
+
+	radio_remove_unstarted_work(wpa_s, NULL);
 }
 
 

wpa_supplicant/wpa_supplicant.c

@@ -1,6 +1,6 @@
 /*
  * WPA Supplicant
- * Copyright (c) 2003-2012, Jouni Malinen <j@w1.fi>
+ * Copyright (c) 2003-2014, Jouni Malinen <j@w1.fi>
  *
  * This software may be distributed under the terms of the BSD license.
  * See README for more details.
@@ -54,7 +54,7 @@
 
 const char *wpa_supplicant_version =
 "wpa_supplicant v" VERSION_STR "\n"
-"Copyright (c) 2003-2013, Jouni Malinen <j@w1.fi> and contributors";
+"Copyright (c) 2003-2014, Jouni Malinen <j@w1.fi> and contributors";
 
 const char *wpa_supplicant_license =
 "This software may be distributed under the terms of the BSD license.\n"
@@ -2894,12 +2894,65 @@ static struct wpa_radio * radio_add_interface(struct wpa_supplicant *wpa_s,
 	if (rn)
 		os_strlcpy(radio->name, rn, sizeof(radio->name));
 	dl_list_init(&radio->ifaces);
+	dl_list_init(&radio->work);
 	dl_list_add(&radio->ifaces, &wpa_s->radio_list);
 
 	return radio;
 }
 
 
+static void radio_work_free(struct wpa_radio_work *work)
+{
+	dl_list_del(&work->list);
+	os_free(work);
+}
+
+
+static void radio_start_next_work(void *eloop_ctx, void *timeout_ctx)
+{
+	struct wpa_radio *radio = eloop_ctx;
+	struct wpa_radio_work *work;
+	struct os_reltime now, diff;
+
+	work = dl_list_first(&radio->work, struct wpa_radio_work, list);
+	if (work == NULL)
+		return;
+
+	if (work->started)
+		return; /* already started and still in progress */
+
+	os_get_reltime(&now);
+	os_reltime_sub(&now, &work->time, &diff);
+	wpa_dbg(work->wpa_s, MSG_DEBUG, "Starting radio work '%s'@%p after %ld.%06ld second wait",
+		work->type, work, diff.sec, diff.usec);
+	work->started = 1;
+	work->time = now;
+	work->cb(work, 0);
+}
+
+
+void radio_remove_unstarted_work(struct wpa_supplicant *wpa_s, const char *type)
+{
+	struct wpa_radio_work *work, *tmp;
+	struct wpa_radio *radio = wpa_s->radio;
+
+	dl_list_for_each_safe(work, tmp, &radio->work, struct wpa_radio_work,
+			      list) {
+		if (type && (work->started || os_strcmp(type, work->type) != 0))
+			continue;
+		if (work->started) {
+			wpa_dbg(wpa_s, MSG_DEBUG, "Leaving started radio work '%s'@%p in the list",
+				work->type, work);
+			continue;
+		}
+		wpa_dbg(wpa_s, MSG_DEBUG, "Remove unstarted radio work '%s'@%p",
+			work->type, work);
+		work->cb(work, 1);
+		radio_work_free(work);
+	}
+}
+
+
 static void radio_remove_interface(struct wpa_supplicant *wpa_s)
 {
 	struct wpa_radio *radio = wpa_s->radio;
@@ -2910,16 +2963,109 @@ static void radio_remove_interface(struct wpa_supplicant *wpa_s)
 	wpa_printf(MSG_DEBUG, "Remove interface %s from radio %s",
 		   wpa_s->ifname, radio->name);
 	dl_list_del(&wpa_s->radio_list);
-	wpa_s->radio = NULL;
-
-	if (!dl_list_empty(&radio->ifaces))
+	if (!dl_list_empty(&radio->ifaces)) {
+		wpa_s->radio = NULL;
 		return; /* Interfaces remain for this radio */
+	}
 
 	wpa_printf(MSG_DEBUG, "Remove radio %s", radio->name);
+	radio_remove_unstarted_work(wpa_s, NULL);
+	eloop_cancel_timeout(radio_start_next_work, radio, NULL);
+	wpa_s->radio = NULL;
 	os_free(radio);
 }
 
 
+static void radio_work_check_next(struct wpa_supplicant *wpa_s)
+{
+	struct wpa_radio *radio = wpa_s->radio;
+
+	if (dl_list_empty(&radio->work))
+		return;
+	eloop_cancel_timeout(radio_start_next_work, radio, NULL);
+	eloop_register_timeout(0, 0, radio_start_next_work, radio, NULL);
+}
+
+
+/**
+ * radio_add_work - Add a radio work item
+ * @wpa_s: Pointer to wpa_supplicant data
+ * @freq: Frequency of the offchannel operation in MHz or 0
+ * @type: Unique identifier for each type of work
+ * @next: Force as the next work to be executed
+ * @cb: Callback function for indicating when radio is available
+ * @ctx: Context pointer for the work (work->ctx in cb())
+ * Returns: 0 on success, -1 on failure
+ *
+ * This function is used to request time for an operation that requires
+ * exclusive radio control. Once the radio is available, the registered callback
+ * function will be called. radio_work_done() must be called once the exclusive
+ * radio operation has been completed, so that the radio is freed for other
+ * operations. The special case of deinit=1 is used to free the context data
+ * during interface removal. That does not allow the callback function to start
+ * the radio operation, i.e., it must free any resources allocated for the radio
+ * work and return.
+ *
+ * The @freq parameter can be used to indicate a single channel on which the
+ * offchannel operation will occur. This may allow multiple radio work
+ * operations to be performed in parallel if they apply for the same channel.
+ * Setting this to 0 indicates that the work item may use multiple channels or
+ * requires exclusive control of the radio.
+ */
+int radio_add_work(struct wpa_supplicant *wpa_s, unsigned int freq,
+		   const char *type, int next,
+		   void (*cb)(struct wpa_radio_work *work, int deinit),
+		   void *ctx)
+{
+	struct wpa_radio_work *work;
+	int was_empty;
+
+	work = os_zalloc(sizeof(*work));
+	if (work == NULL)
+		return -1;
+	wpa_dbg(wpa_s, MSG_DEBUG, "Add radio work '%s'@%p", type, work);
+	os_get_reltime(&work->time);
+	work->freq = freq;
+	work->type = type;
+	work->wpa_s = wpa_s;
+	work->cb = cb;
+	work->ctx = ctx;
+
+	was_empty = dl_list_empty(&wpa_s->radio->work);
+	if (next)
+		dl_list_add(&wpa_s->radio->work, &work->list);
+	else
+		dl_list_add_tail(&wpa_s->radio->work, &work->list);
+	if (was_empty) {
+		wpa_dbg(wpa_s, MSG_DEBUG, "First radio work item in the queue - schedule start immediately");
+		radio_work_check_next(wpa_s);
+	}
+
+	return 0;
+}
+
+
+/**
+ * radio_work_done - Indicate that a radio work item has been completed
+ * @work: Completed work
+ *
+ * This function is called once the callback function registered with
+ * radio_add_work() has completed its work.
+ */
+void radio_work_done(struct wpa_radio_work *work)
+{
+	struct wpa_supplicant *wpa_s = work->wpa_s;
+	struct os_reltime now, diff;
+
+	os_get_reltime(&now);
+	os_reltime_sub(&now, &work->time, &diff);
+	wpa_dbg(wpa_s, MSG_DEBUG, "Radio work '%s'@%p done in %ld.%06ld seconds",
+		work->type, work, diff.sec, diff.usec);
+	radio_work_free(work);
+	radio_work_check_next(wpa_s);
+}
+
+
 static int wpas_init_driver(struct wpa_supplicant *wpa_s,
 			    struct wpa_interface *iface)
 {

wpa_supplicant/wpa_supplicant_i.h

@@ -1,6 +1,6 @@
 /*
  * wpa_supplicant - Internal definitions
- * Copyright (c) 2003-2012, Jouni Malinen <j@w1.fi>
+ * Copyright (c) 2003-2014, Jouni Malinen <j@w1.fi>
  *
  * This software may be distributed under the terms of the BSD license.
  * See README for more details.
@@ -281,8 +281,31 @@ struct wpa_radio {
 	char name[16]; /* from driver_ops get_radio_name() or empty if not
 			* available */
 	struct dl_list ifaces; /* struct wpa_supplicant::radio_list entries */
+	struct dl_list work; /* struct wpa_radio_work::list entries */
 };
 
+/**
+ * struct wpa_radio_work - Radio work item
+ */
+struct wpa_radio_work {
+	struct dl_list list;
+	unsigned int freq; /* known frequency (MHz) or 0 for multiple/unknown */
+	const char *type;
+	struct wpa_supplicant *wpa_s;
+	void (*cb)(struct wpa_radio_work *work, int deinit);
+	void *ctx;
+	unsigned int started:1;
+	struct os_reltime time;
+};
+
+int radio_add_work(struct wpa_supplicant *wpa_s, unsigned int freq,
+		   const char *type, int next,
+		   void (*cb)(struct wpa_radio_work *work, int deinit),
+		   void *ctx);
+void radio_work_done(struct wpa_radio_work *work);
+void radio_remove_unstarted_work(struct wpa_supplicant *wpa_s,
+				 const char *type);
+
 /**
  * offchannel_send_action_result - Result of offchannel send Action frame
  */