net: ieee802154: Add grounds for passive scan

Currently, as only CC2520 device is supported: it will loop over the 16
channels present in 2.4Ghz spectrum. However, this will need refinement
as soon as other spectrums will be in use: L2 layer could request
capabilites from the device in order to know which range to use.

Scan result is done one at a time for now. It's unlikely going to fit
all production use case, so it's going to change in the future.

Change-Id: I2fafec49eb5cbfca1a4f04107ba3b6511d7d956d
Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>

include/net/ieee802154.h

@@ -24,12 +24,18 @@
 
 #include <net/net_mgmt.h>
 
+#define IEEE802154_MAX_ADDR_LENGTH	8
+
 /* This not meant to be used by any code but 802.15.4 L2 stack */
 struct ieee802154_context {
 	uint16_t pan_id;
 	uint16_t channel;
 	uint8_t sequence;
 	struct k_sem ack_lock;
+#ifdef CONFIG_NET_L2_IEEE802154_MGMT
+	struct ieee802154_req_params *scan_ctx;
+	struct k_sem res_lock;
+#endif
 	uint8_t ack_received	: 1;
 	uint8_t ack_requested	: 1;
 	uint8_t _unused		: 6;
@@ -43,10 +49,13 @@ struct ieee802154_context {
 #define _NET_IEEE802154_BASE	(NET_MGMT_IFACE_BIT |			\
 				 NET_MGMT_LAYER(_NET_IEEE802154_LAYER) |\
 				 NET_MGMT_LAYER_CODE(_NET_IEEE802154_CODE))
+#define _NET_IEEE802154_EVENT	(_NET_IEEE802154_BASE | NET_MGMT_EVENT_BIT)
 
 enum net_request_ieee802154_cmd {
 	NET_REQUEST_IEEE802154_CMD_SET_ACK = 1,
 	NET_REQUEST_IEEE802154_CMD_UNSET_ACK,
+	NET_REQUEST_IEEE802154_CMD_PASSIVE_SCAN,
+	NET_REQUEST_IEEE802154_CMD_CANCEL_SCAN,
 };
 
 
@@ -60,4 +69,62 @@ NET_MGMT_DEFINE_REQUEST_HANDLER(NET_REQUEST_IEEE802154_SET_ACK);
 
 NET_MGMT_DEFINE_REQUEST_HANDLER(NET_REQUEST_IEEE802154_UNSET_ACK);
 
+#define NET_REQUEST_IEEE802154_PASSIVE_SCAN				\
+	(_NET_IEEE802154_BASE | NET_REQUEST_IEEE802154_CMD_PASSIVE_SCAN)
+
+NET_MGMT_DEFINE_REQUEST_HANDLER(NET_REQUEST_IEEE802154_PASSIVE_SCAN);
+
+#define NET_REQUEST_IEEE802154_CANCEL_SCAN				\
+	(_NET_IEEE802154_BASE | NET_REQUEST_IEEE802154_CMD_CANCEL_SCAN)
+
+NET_MGMT_DEFINE_REQUEST_HANDLER(NET_REQUEST_IEEE802154_CANCEL_SCAN);
+
+enum net_event_ieee802154_cmd {
+	NET_EVENT_IEEE802154_CMD_SCAN_RESULT = 1,
+};
+
+
+#define NET_EVENT_IEEE802154_SCAN_RESULT				\
+	(_NET_IEEE802154_EVENT | NET_EVENT_IEEE802154_CMD_SCAN_RESULT)
+
+
+#define IEEE802154_IS_CHAN_SCANNED(_channel_set, _chan)	\
+	(_channel_set & BIT(_chan - 1))
+#define IEEE802154_IS_CHAN_UNSCANNED(_channel_set, _chan)	\
+	(!IEEE802154_IS_CHAN_SCANNED(_channel_set, _chan))
+
+/* Useful define to request all channels to be scanned,
+ * from 11 to 26 included.
+ */
+#define IEEE802154_ALL_CHANNELS	(0x03FFFC00)
+
+/**
+ * @brief Scanning parameters
+ *
+ * Used to request a scan and get results as well
+ */
+struct ieee802154_req_params {
+	/** The set of channels to scan, use above macros to manage it */
+	uint32_t channel_set;
+
+	/** Duration of scan, per-channel, in milliseconds */
+	uint32_t duration;
+
+	/** Current channel in use as a result */
+	uint16_t channel;
+	/** Current pan_id in use as a result */
+	uint16_t pan_id;
+
+	/** Result address */
+	union {
+		uint8_t addr[IEEE802154_MAX_ADDR_LENGTH];
+		uint16_t short_addr;
+	};
+
+	/** length of address */
+	uint8_t len;
+	/** Link quality information, between 0 and 255 */
+	uint8_t lqi;
+} __packed;
+
 #endif /* __IEEE802154_H__ */

subsys/net/ip/l2/ieee802154/ieee802154_mgmt.c

@@ -17,8 +17,121 @@
 #include <errno.h>
 
 #include <net/net_if.h>
+#include <net/ieee802154_radio.h>
 #include <net/ieee802154.h>
 
+#include "ieee802154_frame.h"
+#include "ieee802154_mgmt.h"
+
+enum net_verdict ieee802154_handle_beacon(struct net_if *iface,
+					  struct ieee802154_mpdu *mpdu)
+{
+	struct ieee802154_context *ctx = net_if_l2_data(iface);
+	struct ieee802154_radio_api *radio =
+		(struct ieee802154_radio_api *)iface->dev->driver_api;
+
+	if (!ctx->scan_ctx) {
+		return NET_DROP;
+	}
+
+	if (!mpdu->beacon->sf.association) {
+		return NET_DROP;
+	}
+
+	k_sem_take(&ctx->res_lock, K_FOREVER);
+
+	ctx->scan_ctx->pan_id = mpdu->mhr.src_addr->plain.pan_id;
+	ctx->scan_ctx->lqi = radio->get_lqi(iface->dev);
+
+	if (mpdu->mhr.fs->fc.src_addr_mode == IEEE802154_ADDR_MODE_SHORT) {
+		ctx->scan_ctx->len = IEEE802154_SHORT_ADDR_LENGTH;
+		ctx->scan_ctx->short_addr =
+			mpdu->mhr.src_addr->plain.addr.short_addr;
+	} else {
+		ctx->scan_ctx->len = IEEE802154_EXT_ADDR_LENGTH;
+		sys_memcpy_swap(ctx->scan_ctx->addr,
+				mpdu->mhr.src_addr->plain.addr.ext_addr,
+				IEEE802154_EXT_ADDR_LENGTH);
+	}
+
+	net_mgmt_event_notify(NET_EVENT_IEEE802154_SCAN_RESULT, iface);
+
+	k_sem_give(&ctx->res_lock);
+
+	return NET_OK;
+}
+
+static int ieee802154_cancel_scan(uint32_t mgmt_request, struct net_if *iface,
+				  void *data, size_t len)
+{
+	struct ieee802154_context *ctx = net_if_l2_data(iface);
+
+	ARG_UNUSED(data);
+	ARG_UNUSED(len);
+
+	ctx->scan_ctx = NULL;
+
+	return 0;
+}
+
+NET_MGMT_REGISTER_REQUEST_HANDLER(NET_REQUEST_IEEE802154_CANCEL_SCAN,
+				  ieee802154_cancel_scan);
+
+static int ieee802154_scan(uint32_t mgmt_request, struct net_if *iface,
+			   void *data, size_t len)
+{
+	struct ieee802154_radio_api *radio =
+		(struct ieee802154_radio_api *)iface->dev->driver_api;
+	struct ieee802154_context *ctx = net_if_l2_data(iface);
+	struct ieee802154_req_params *scan =
+		(struct ieee802154_req_params *)data;
+	uint8_t channel;
+	int ret;
+
+	if (ctx->scan_ctx) {
+		return -EALREADY;
+	}
+
+	if (radio->start(iface->dev)) {
+		return -EIO;
+	}
+
+	ctx->scan_ctx = scan;
+	ret = 0;
+
+	radio->set_pan_id(iface->dev, IEEE802154_BROADCAST_PAN_ID);
+
+	/* ToDo: For now, we assume we are on 2.4Ghz
+	 * (device will have to export capabilities) */
+	for (channel = 11; channel <= 26; channel++) {
+		if (IEEE802154_IS_CHAN_UNSCANNED(scan->channel_set, channel)) {
+			continue;
+		}
+
+		scan->channel = channel;
+		radio->set_channel(iface->dev, channel);
+
+		/* Context aware sleep */
+		k_sleep(scan->duration);
+
+		if (!ctx->scan_ctx) {
+			ret = -ECANCELED;
+			break;
+		}
+	}
+
+	/* Let's come back to context's settings */
+	radio->set_pan_id(iface->dev, ctx->pan_id);
+	radio->set_channel(iface->dev, ctx->channel);
+
+	ctx->scan_ctx = NULL;
+
+	return ret;
+}
+
+NET_MGMT_REGISTER_REQUEST_HANDLER(NET_REQUEST_IEEE802154_PASSIVE_SCAN,
+				  ieee802154_scan);
+
 static int ieee802154_set_ack(uint32_t mgmt_request, struct net_if *iface,
 			      void *data, size_t len)
 {

subsys/net/ip/l2/ieee802154/ieee802154_mgmt.h

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2016 Intel Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @file
+ * @brief IEEE 802.15.4 Management
+ */
+
+#ifndef __IEEE802154_MGMT_H__
+#define __IEEE802154_MGMT_H__
+
+#ifdef CONFIG_NET_MGMT
+
+static inline bool ieee802154_is_scanning(struct net_if *iface)
+{
+	struct ieee802154_context *ctx = net_if_l2_data(iface);
+
+	return !(!ctx->scan_ctx);
+}
+
+static inline void ieee802154_mgmt_init(struct net_if *iface)
+{
+	struct ieee802154_context *ctx = net_if_l2_data(iface);
+
+	k_sem_init(&ctx->res_lock, 1, 1);
+}
+
+enum net_verdict ieee802154_handle_beacon(struct net_if *iface,
+					  struct ieee802154_mpdu *mpdu);
+
+#else /* CONFIG_NET_MGMT */
+
+#define ieee802154_is_scanning(...) false
+#define ieee802154_mgmt_init(...)
+#define ieee802154_handle_beacon(...) NET_DROP
+
+#endif /* CONFIG_NET_MGMT */
+
+#endif /* __IEEE802154_MGMT_H__ */