dpp: manually register for some frame watches

The frame watch which covers the presence procedure (and most
frames for that matter) needs to support multicast frames for
presence to work. Doing this in frame-xchg seems like the right
choice but only ath9k supports multicast frame registration.
Because of this limited support DPP will register for these frames
manually.

src/dpp.c

@@ -61,6 +61,9 @@ static struct l_genl_family *nl80211;
 static uint8_t broadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 static struct l_queue *dpp_list;
 static uint32_t mlme_watch;
+static uint32_t unicast_watch;
+
+static uint8_t dpp_prefix[] = { 0x04, 0x09, 0x50, 0x6f, 0x9a, 0x1a, 0x01 };
 
 enum dpp_state {
 	DPP_STATE_NOTHING,
@@ -127,6 +130,8 @@ struct dpp_sm {
 	uint8_t frame_retry;
 
 	struct l_dbus_message *pending;
+
+	bool mcast_support : 1;
 };
 
 static void dpp_free_auth_data(struct dpp_sm *dpp)
@@ -1403,6 +1408,9 @@ static void authenticate_request(struct dpp_sm *dpp, const uint8_t *from,
 	const void *ad1 = body + 8;
 	uint32_t freq;
 
+	if (util_is_broadcast_address(from))
+		return;
+
 	if (dpp->state != DPP_STATE_PRESENCE)
 		return;
 
@@ -1577,11 +1585,10 @@ auth_request_failed:
 	dpp_free_auth_data(dpp);
 }
 
-static void dpp_handle_frame(const struct mmpdu_header *frame,
+static void dpp_handle_frame(struct dpp_sm *dpp,
-				const void *body, size_t body_len,
+				const struct mmpdu_header *frame,
-				int rssi, void *user_data)
+				const void *body, size_t body_len)
 {
-	struct dpp_sm *dpp = user_data;
 	const uint8_t *ptr;
 
 	/*
@@ -1664,11 +1671,103 @@ static void dpp_mlme_notify(struct l_genl_msg *msg, void *user_data)
 	dpp_send_frame(dpp, &iov, 1, dpp->current_freq);
 }
 
+static void dpp_unicast_notify(struct l_genl_msg *msg, void *user_data)
+{
+	struct dpp_sm *dpp;
+	const uint64_t *wdev_id = NULL;
+	struct l_genl_attr attr;
+	uint16_t type, len, frame_len;
+	const void *data;
+	const struct mmpdu_header *mpdu = NULL;
+	const uint8_t *body;
+	size_t body_len;
+
+	if (l_genl_msg_get_command(msg) != NL80211_CMD_FRAME)
+		return;
+
+	if (!l_genl_attr_init(&attr, msg))
+		return;
+
+	while (l_genl_attr_next(&attr, &type, &len, &data)) {
+		switch (type) {
+		case NL80211_ATTR_WDEV:
+			if (len != 8)
+				break;
+
+			wdev_id = data;
+			break;
+
+		case NL80211_ATTR_FRAME:
+			mpdu = mpdu_validate(data, len);
+			if (!mpdu) {
+				l_warn("Frame didn't validate as MMPDU");
+				return;
+			}
+
+			frame_len = len;
+			break;
+		}
+	}
+
+	if (!wdev_id) {
+		l_warn("Bad wdev attribute");
+		return;
+	}
+
+	dpp = l_queue_find(dpp_list, match_wdev, wdev_id);
+	if (!dpp)
+		return;
+
+	if (!mpdu) {
+		l_warn("Missing frame data");
+		return;
+	}
+
+	body = mmpdu_body(mpdu);
+	body_len = (const uint8_t *) mpdu + frame_len - body;
+
+	if (body_len < sizeof(dpp_prefix) ||
+			memcmp(body, dpp_prefix, sizeof(dpp_prefix)) != 0)
+		return;
+
+	dpp_handle_frame(dpp, mpdu, body, body_len);
+}
+
+static void dpp_frame_watch_cb(struct l_genl_msg *msg, void *user_data)
+{
+	if (l_genl_msg_get_error(msg) < 0)
+		l_error("Could not register frame watch type %04x: %i",
+			L_PTR_TO_UINT(user_data), l_genl_msg_get_error(msg));
+}
+
+/*
+ * Special case the frame watch which includes the presence frames since they
+ * require multicast support. This is only supported by ath9k, so adding
+ * general support to frame-xchg isn't desireable.
+ */
+static void dpp_frame_watch(struct dpp_sm *dpp, uint16_t frame_type,
+				const uint8_t *prefix, size_t prefix_len)
+{
+	struct l_genl_msg *msg;
+
+	msg = l_genl_msg_new_sized(NL80211_CMD_REGISTER_FRAME, 32 + prefix_len);
+
+	l_genl_msg_append_attr(msg, NL80211_ATTR_WDEV, 8, &dpp->wdev_id);
+	l_genl_msg_append_attr(msg, NL80211_ATTR_FRAME_TYPE, 2, &frame_type);
+	l_genl_msg_append_attr(msg, NL80211_ATTR_FRAME_MATCH,
+				prefix_len, prefix);
+	if (dpp->mcast_support)
+		l_genl_msg_append_attr(msg, NL80211_ATTR_RECEIVE_MULTICAST,
+					0, NULL);
+
+	l_genl_family_send(nl80211, msg, dpp_frame_watch_cb,
+					L_UINT_TO_PTR(frame_type), NULL);
+}
+
 static void dpp_create(struct netdev *netdev)
 {
 	struct l_dbus *dbus = dbus_get_bus();
 	struct dpp_sm *dpp = l_new(struct dpp_sm, 1);
-	uint8_t dpp_prefix[] = { 0x04, 0x09, 0x50, 0x6f, 0x9a, 0x1a, 0x01 };
 	uint8_t dpp_conf_response_prefix[] = { 0x04, 0x0b };
 	uint8_t dpp_conf_request_prefix[] = { 0x04, 0x0a };
 
@@ -1678,6 +1777,9 @@ static void dpp_create(struct netdev *netdev)
 	dpp->curve = l_ecc_curve_from_ike_group(19);
 	dpp->key_len = l_ecc_curve_get_scalar_bytes(dpp->curve);
 	dpp->nonce_len = dpp_nonce_len_from_key_len(dpp->key_len);
+	dpp->mcast_support = wiphy_has_ext_feature(
+				wiphy_find_by_wdev(dpp->wdev_id),
+				NL80211_EXT_FEATURE_MULTICAST_REGISTRATIONS);
 
 	l_ecdh_generate_key_pair(dpp->curve, &dpp->boot_private,
 					&dpp->boot_public);
@@ -1690,9 +1792,8 @@ static void dpp_create(struct netdev *netdev)
 	l_dbus_object_add_interface(dbus, netdev_get_path(netdev),
 					IWD_DPP_INTERFACE, dpp);
 
-	frame_watch_add(netdev_get_wdev_id(netdev), 0, 0x00d0, dpp_prefix,
+	dpp_frame_watch(dpp, 0x00d0, dpp_prefix, sizeof(dpp_prefix));
-				sizeof(dpp_prefix), dpp_handle_frame,
+
-				dpp, NULL);
 	frame_watch_add(netdev_get_wdev_id(netdev), 0, 0x00d0,
 				dpp_conf_response_prefix,
 				sizeof(dpp_conf_response_prefix),
@@ -1935,6 +2036,11 @@ static int dpp_init(void)
 	mlme_watch = l_genl_family_register(nl80211, "mlme", dpp_mlme_notify,
 						NULL, NULL);
 
+	unicast_watch = l_genl_add_unicast_watch(iwd_get_genl(),
+						NL80211_GENL_NAME,
+						dpp_unicast_notify,
+						NULL, NULL);
+
 	dpp_list = l_queue_new();
 
 	return 0;
@@ -1948,6 +2054,8 @@ static void dpp_exit(void)
 
 	netdev_watch_remove(netdev_watch);
 
+	l_genl_remove_unicast_watch(iwd_get_genl(), unicast_watch);
+
 	l_genl_family_unregister(nl80211, mlme_watch);
 	mlme_watch = 0;