p2p: Scan for the provision BSS

Add the next step after Provision Discovery or GO Negotiation that is
scanning for the WSC BSS that the GO has set up for client provisioning.

src/p2p.c

@@ -86,11 +86,13 @@ struct p2p_device {
 	char *conn_pin;
 	uint8_t conn_addr[6];
 	uint16_t conn_password_id;
+	struct scan_bss *conn_wsc_bss;
 
 	struct l_timeout *config_timeout;
 	unsigned long go_config_delay;
 	struct l_timeout *go_neg_req_timeout;
 	uint8_t go_dialog_token;
+	unsigned int go_scan_retry;
 	uint32_t go_oper_freq;
 	struct p2p_group_id_attr go_group_id;
 	uint8_t go_interface_addr[6];
@@ -329,6 +331,10 @@ static void p2p_connect_failed(struct p2p_device *dev)
 	if (!peer)
 		return;
 
+	/* Are we in the scan for the WSC provision bss */
+	if (dev->scan_id)
+		scan_cancel(dev->wdev_id, dev->scan_id);
+
 	if (peer->wsc.pending_connect)
 		dbus_pending_reply(&peer->wsc.pending_connect,
 				dbus_error_failed(peer->wsc.pending_connect));
@@ -420,6 +426,11 @@ static const struct frame_xchg_prefix p2p_frame_pd_resp = {
 	.len = 7,
 };
 
+static void p2p_device_interface_create(struct p2p_device *dev)
+{
+	/* TODO */
+}
+
 static void p2p_scan_destroy(void *user_data)
 {
 	struct p2p_device *dev = user_data;
@@ -427,6 +438,215 @@ static void p2p_scan_destroy(void *user_data)
 	dev->scan_id = 0;
 }
 
+static void p2p_provision_scan_start(struct p2p_device *dev);
+
+static bool p2p_provision_scan_notify(int err, struct l_queue *bss_list,
+					void *user_data)
+{
+	struct p2p_device *dev = user_data;
+	const struct l_queue_entry *entry;
+	static const uint8_t wildcard_addr[6] =
+		{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
+
+	l_debug("err=%i, len(bss_list)=%i", err, l_queue_length(bss_list));
+
+	if (err) {
+		l_error("P2P provision scan failed: %s (%i)", strerror(-err),
+			-err);
+		p2p_connect_failed(dev);
+		return false;
+	}
+
+	for (entry = l_queue_get_entries(bss_list); entry;
+			entry = entry->next) {
+		struct scan_bss *bss = entry->data;
+		const uint8_t *group_id;
+		bool selected_reg;
+		struct p2p_capability_attr *capability;
+		enum wsc_device_password_id device_password_id;
+		const uint8_t *amacs;
+
+		/*
+		 * Check if we found our target GO, some of these checks may
+		 * need to be gradually relaxed as we discover non-compliant
+		 * implementations but at least print a debug statement when
+		 * something doesn't match.
+		 */
+
+		if (strncmp((const char *) bss->ssid, dev->go_group_id.ssid,
+				bss->ssid_len))
+			continue;
+
+		if (dev->go_group_id.ssid[bss->ssid_len] != '\0')
+			continue;
+
+		if (!util_mem_is_zero(dev->go_interface_addr, 6) &&
+				memcmp(bss->addr, dev->go_interface_addr, 6))
+			l_debug("SSID matched but BSSID didn't match the GO's "
+				"intended interface addr, proceeding anyway");
+
+		if (!bss->wsc) {
+			l_error("SSID matched but no valid WSC IE");
+			continue;
+		}
+
+		if (bss->source_frame == SCAN_BSS_PROBE_RESP) {
+			struct wsc_probe_response wsc_info;
+
+			if (!bss->p2p_probe_resp_info) {
+				l_error("SSID matched but no valid P2P IE");
+				continue;
+			}
+
+			if (wsc_parse_probe_response(bss->wsc, bss->wsc_size,
+							&wsc_info) < 0) {
+				l_error("SSID matched but can't parse WSC "
+					"Probe Response info");
+				continue;
+			}
+
+			group_id = bss->p2p_probe_resp_info->
+				device_info.device_addr;
+			selected_reg = wsc_info.selected_registrar;
+			capability = &bss->p2p_probe_resp_info->capability;
+			device_password_id = wsc_info.device_password_id;
+			amacs = wsc_info.authorized_macs;
+		} else if (bss->source_frame == SCAN_BSS_BEACON) {
+			struct wsc_beacon wsc_info;
+
+			if (!bss->p2p_beacon_info) {
+				l_error("SSID matched but no valid P2P IE");
+				continue;
+			}
+
+			if (wsc_parse_beacon(bss->wsc, bss->wsc_size,
+						&wsc_info) < 0) {
+				l_error("SSID matched but can't parse WSC "
+					"Beacon info");
+				continue;
+			}
+
+			group_id = bss->p2p_beacon_info->device_addr;
+			selected_reg = wsc_info.selected_registrar;
+			capability = &bss->p2p_beacon_info->capability;
+			device_password_id = wsc_info.device_password_id;
+			amacs = wsc_info.authorized_macs;
+		} else
+			continue;
+
+		if (memcmp(group_id, dev->go_group_id.device_addr, 6)) {
+			l_error("SSID matched but Group ID address didn't");
+			continue;
+		}
+
+		if (!selected_reg) {
+			/*
+			 * Debug level because this will sometimes happen
+			 * while the target is setting up the GO mode in the
+			 * course of normal operation, and gets set to true
+			 * in a few seconds, we just need to keep scanning.
+			 */
+			l_debug("SSID matched but not a Selected Reg");
+			continue;
+		}
+
+		if (dev->conn_peer->group && (capability->group_caps &
+					P2P_GROUP_CAP_GROUP_FORMATION)) {
+			l_error("SSID matched but not in Group Formation");
+			continue;
+		}
+
+		if (!dev->conn_peer->group && !(capability->group_caps &
+					P2P_GROUP_CAP_GROUP_FORMATION))
+			/*
+			 * We have to ignore this one for interoperability
+			 * with some devices.
+			 */
+			l_debug("SSID matched but GO not in Group Formation, "
+				"proceeding anyway");
+
+		if (capability->group_caps & P2P_GROUP_CAP_GROUP_LIMIT) {
+			l_error("SSID matched but group already full");
+			continue;
+		}
+
+		if (device_password_id != dev->conn_password_id) {
+			l_error("SSID matched wrong Password ID");
+			continue;
+		}
+
+		if (!util_mem_is_zero(amacs, 30)) {
+			bool amacs_match = false;
+			int i;
+
+			for (i = 0; i < 5; i++, amacs += 6)
+				if (!memcmp(amacs, dev->addr, 6) ||
+						!memcmp(amacs, wildcard_addr, 6))
+					amacs_match = true;
+
+			if (!amacs_match) {
+				l_error("SSID matched we're not in AMacs");
+				continue;
+			}
+		}
+
+		l_debug("GO found in the scan results");
+
+		dev->conn_wsc_bss = bss;
+		p2p_device_interface_create(dev);
+		l_queue_remove(bss_list, bss);
+		l_queue_destroy(bss_list,
+				(l_queue_destroy_func_t) scan_bss_free);
+		return true;
+	}
+
+	/* Retry a few times if the WSC AP not found or not ready */
+	dev->go_scan_retry++;
+
+	if (dev->go_scan_retry > 15) {
+		p2p_connect_failed(dev);
+		return false;
+	}
+
+	p2p_provision_scan_start(dev);
+	return false;
+}
+
+static void p2p_provision_scan_start(struct p2p_device *dev)
+{
+	struct scan_parameters params = {};
+	uint8_t buf[256];
+
+	params.flush = true;
+	params.no_cck_rates = true;
+	params.ssid = dev->go_group_id.ssid;
+	params.extra_ie = p2p_build_scan_ies(dev, buf, sizeof(buf),
+						&params.extra_ie_size);
+	L_WARN_ON(!params.extra_ie);
+
+	/*
+	 * Initially scan just the Operating Channel the GO reported
+	 * during the negotiation.  In theory there's no guarantee that
+	 * it is going to be on that channel so we should fall back
+	 * to scanning all the channels listed in the Channel List
+	 * attribute.  For simplicity we just do a full scan in that
+	 * scenario -- for most target P2P devices we wouldn't be saving
+	 * ourselves any work anyway as the Channel List is going to
+	 * contain all of the 2.4 and 5G channels.
+	 */
+	if (dev->go_scan_retry < 12) {
+		params.freqs = scan_freq_set_new();
+		scan_freq_set_add(params.freqs, dev->go_oper_freq);
+	}
+
+	dev->scan_id = scan_active_full(dev->wdev_id, &params, NULL,
+					p2p_provision_scan_notify, dev,
+					p2p_scan_destroy);
+
+	if (params.freqs)
+		scan_freq_set_free(params.freqs);
+}
+
 static void p2p_start_client_provision(struct p2p_device *dev)
 {
 	char bssid_str[18];
@@ -437,7 +657,8 @@ static void p2p_start_client_provision(struct p2p_device *dev)
 		util_address_to_string(dev->go_group_id.device_addr),
 		bssid_str);
 
-	/* TODO: start client provisioning */
+	dev->go_scan_retry = 0;
+	p2p_provision_scan_start(dev);
 }
 
 static void p2p_config_timeout_destroy(void *user_data)