mac802154: Handle active scanning

Active scan support is based on the current passive scan support,
cheered up with beacon requests sent after every channel change.

Co-developed-by: David Girault <[e-mail]>
Signed-off-by: David Girault <[e-mail]>
Signed-off-by: Miquel Raynal <[e-mail]>
Acked-by: Alexander Aring <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Stefan Schmidt <[e-mail]>

include/net/ieee802154_netdev.h

···
 #endif
 } __packed;
 
+struct ieee802154_mac_cmd_pl {
+	u8  cmd_id;
+} __packed;
+
 struct ieee802154_sechdr {
 #if defined(__LITTLE_ENDIAN_BITFIELD)
 	u8 level:3,
···
 	struct ieee802154_beacon_hdr mac_pl;
 };
 
+struct ieee802154_mac_cmd_frame {
+	struct ieee802154_hdr mhr;
+	struct ieee802154_mac_cmd_pl mac_pl;
+};
+
+struct ieee802154_beacon_req_frame {
+	struct ieee802154_hdr mhr;
+	struct ieee802154_mac_cmd_pl mac_pl;
+};
+
 /* pushes hdr onto the skb. fields of hdr->fc that can be calculated from
  * the contents of hdr will be, and the actual value of those bits in
  * hdr->fc will be ignored. this includes the INTRA_PAN bit and the frame
···
  */
 int ieee802154_hdr_peek(const struct sk_buff *skb, struct ieee802154_hdr *hdr);
 
-/* pushes a beacon frame into an skb */
+/* pushes/pulls various frame types into/from an skb */
 int ieee802154_beacon_push(struct sk_buff *skb,
 			   struct ieee802154_beacon_frame *beacon);
+int ieee802154_mac_cmd_push(struct sk_buff *skb, void *frame,
+			    const void *pl, unsigned int pl_len);
 
 int ieee802154_max_payload(const struct ieee802154_hdr *hdr);
 

net/ieee802154/header_ops.c

···
 }
 EXPORT_SYMBOL_GPL(ieee802154_hdr_push);
 
+int ieee802154_mac_cmd_push(struct sk_buff *skb, void *f,
+			    const void *pl, unsigned int pl_len)
+{
+	struct ieee802154_mac_cmd_frame *frame = f;
+	struct ieee802154_mac_cmd_pl *mac_pl = &frame->mac_pl;
+	struct ieee802154_hdr *mhr = &frame->mhr;
+	int ret;
+
+	skb_reserve(skb, sizeof(*mhr));
+	ret = ieee802154_hdr_push(skb, mhr);
+	if (ret < 0)
+		return ret;
+
+	skb_reset_mac_header(skb);
+	skb->mac_len = ret;
+
+	skb_put_data(skb, mac_pl, sizeof(*mac_pl));
+	skb_put_data(skb, pl, pl_len);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(ieee802154_mac_cmd_push);
+
 int ieee802154_beacon_push(struct sk_buff *skb,
 			   struct ieee802154_beacon_frame *beacon)
 {

net/mac802154/ieee802154_i.h

···
 	/* Scanning */
 	u8 scan_page;
 	u8 scan_channel;
+	struct ieee802154_beacon_req_frame scan_beacon_req;
 	struct cfg802154_scan_request __rcu *scan_req;
 	struct delayed_work scan_work;
 

net/mac802154/scan.c

···
 
 #define IEEE802154_BEACON_MHR_SZ 13
 #define IEEE802154_BEACON_PL_SZ 4
+#define IEEE802154_MAC_CMD_MHR_SZ 23
+#define IEEE802154_MAC_CMD_PL_SZ 1
 #define IEEE802154_BEACON_SKB_SZ (IEEE802154_BEACON_MHR_SZ + \
 				  IEEE802154_BEACON_PL_SZ)
+#define IEEE802154_MAC_CMD_SKB_SZ (IEEE802154_MAC_CMD_MHR_SZ + \
+				   IEEE802154_MAC_CMD_PL_SZ)
 
 /* mac802154_scan_cleanup_locked() must be called upon scan completion or abort.
  * - Completions are asynchronous, not locked by the rtnl and decided by the
···
 	return 0;
 }
 
+static int mac802154_scan_prepare_beacon_req(struct ieee802154_local *local)
+{
+	memset(&local->scan_beacon_req, 0, sizeof(local->scan_beacon_req));
+	local->scan_beacon_req.mhr.fc.type = IEEE802154_FC_TYPE_MAC_CMD;
+	local->scan_beacon_req.mhr.fc.dest_addr_mode = IEEE802154_SHORT_ADDRESSING;
+	local->scan_beacon_req.mhr.fc.version = IEEE802154_2003_STD;
+	local->scan_beacon_req.mhr.fc.source_addr_mode = IEEE802154_NO_ADDRESSING;
+	local->scan_beacon_req.mhr.dest.mode = IEEE802154_ADDR_SHORT;
+	local->scan_beacon_req.mhr.dest.pan_id = cpu_to_le16(IEEE802154_PANID_BROADCAST);
+	local->scan_beacon_req.mhr.dest.short_addr = cpu_to_le16(IEEE802154_ADDR_BROADCAST);
+	local->scan_beacon_req.mac_pl.cmd_id = IEEE802154_CMD_BEACON_REQ;
+
+	return 0;
+}
+
+static int mac802154_transmit_beacon_req(struct ieee802154_local *local,
+					 struct ieee802154_sub_if_data *sdata)
+{
+	struct sk_buff *skb;
+	int ret;
+
+	skb = alloc_skb(IEEE802154_MAC_CMD_SKB_SZ, GFP_KERNEL);
+	if (!skb)
+		return -ENOBUFS;
+
+	skb->dev = sdata->dev;
+
+	ret = ieee802154_mac_cmd_push(skb, &local->scan_beacon_req, NULL, 0);
+	if (ret) {
+		kfree_skb(skb);
+		return ret;
+	}
+
+	return ieee802154_mlme_tx(local, sdata, skb);
+}
+
 void mac802154_scan_worker(struct work_struct *work)
 {
 	struct ieee802154_local *local =
···
 		goto end_scan;
 	}
 
+	if (scan_req->type == NL802154_SCAN_ACTIVE) {
+		ret = mac802154_transmit_beacon_req(local, sdata);
+		if (ret)
+			dev_err(&sdata->dev->dev,
+				"Error when transmitting beacon request (%d)\n", ret);
+	}
+
 	ieee802154_configure_durations(wpan_phy, page, channel);
 	scan_duration = mac802154_scan_get_channel_time(scan_req_duration,
 							wpan_phy->symbol_duration);
···
 	if (mac802154_is_scanning(local))
 		return -EBUSY;
 
-	/* TODO: support other scanning type */
-	if (request->type != NL802154_SCAN_PASSIVE)
+	if (request->type != NL802154_SCAN_PASSIVE &&
+	    request->type != NL802154_SCAN_ACTIVE)
 		return -EOPNOTSUPP;
 
 	/* Store scanning parameters */
···
 	local->scan_page = request->page;
 	local->scan_channel = -1;
 	set_bit(IEEE802154_IS_SCANNING, &local->ongoing);
+	if (request->type == NL802154_SCAN_ACTIVE)
+		mac802154_scan_prepare_beacon_req(local);
 
 	nl802154_scan_started(request->wpan_phy, request->wpan_dev);