WNM: Move transition candidate list processing to normal scan

This makes it easier to optimize transition request processing.

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

wpa_supplicant/events.c

@@ -1314,6 +1314,9 @@ static int _wpa_supplicant_event_scan_results(struct wpa_supplicant *wpa_s,
 		return 0;
 	}
 
+	if (wnm_scan_process(wpa_s) > 0)
+		goto scan_work_done;
+
 	if (sme_proc_obss_scan(wpa_s) > 0)
 		goto scan_work_done;
 

wpa_supplicant/wnm_sta.c

@@ -445,41 +445,32 @@ static void wnm_parse_neighbor_report(struct wpa_supplicant *wpa_s,
 }
 
 
-static int compare_scan_neighbor_results(struct wpa_supplicant *wpa_s,
-					 struct wpa_scan_results *scan_res,
-					 struct neighbor_report *neigh_rep,
-					 u8 num_neigh_rep, u8 *bssid_to_connect)
+static struct wpa_bss *
+compare_scan_neighbor_results(struct wpa_supplicant *wpa_s)
 {
 
-	u8 i, j;
-	const u8 *ssid;
+	u8 i;
 	struct wpa_bss *bss = wpa_s->current_bss;
+	struct wpa_bss *target;
 
-	if (scan_res == NULL || num_neigh_rep == 0 || !bss)
+	if (!bss)
 		return 0;
 
 	wpa_printf(MSG_DEBUG, "WNM: Current BSS " MACSTR " RSSI %d",
 		   MAC2STR(wpa_s->bssid), bss->level);
 
-	for (i = 0; i < num_neigh_rep; i++) {
-		struct neighbor_report *nei = &neigh_rep[i];
-		struct wpa_scan_res *res = NULL;
+	for (i = 0; i < wpa_s->wnm_num_neighbor_report; i++) {
+		struct neighbor_report *nei;
 
+		nei = &wpa_s->wnm_neighbor_report_elements[i];
 		if (nei->preference_present && nei->preference == 0) {
 			wpa_printf(MSG_DEBUG, "Skip excluded BSS " MACSTR,
 				   MAC2STR(nei->bssid));
 			continue;
 		}
 
-		for (j = 0; j < scan_res->num; j++) {
-			if (os_memcmp(scan_res->res[j]->bssid,
-				      neigh_rep[i].bssid, ETH_ALEN) == 0) {
-				res = scan_res->res[j];
-				break;
-			}
-		}
-
-		if (!res) {
+		target = wpa_bss_get_bssid(wpa_s, nei->bssid);
+		if (!target) {
 			wpa_printf(MSG_DEBUG, "Candidate BSS " MACSTR
 				   " (pref %d) not found in scan results",
 				   MAC2STR(nei->bssid),
@@ -488,9 +479,8 @@ static int compare_scan_neighbor_results(struct wpa_supplicant *wpa_s,
 			continue;
 		}
 
-		ssid = wpa_scan_get_ie(res, WLAN_EID_SSID);
-		if (ssid == NULL || bss->ssid_len != ssid[1] ||
-		    os_memcmp(bss->ssid, ssid + 2, ssid[1]) != 0) {
+		if (bss->ssid_len != target->ssid_len ||
+		    os_memcmp(bss->ssid, target->ssid, bss->ssid_len) != 0) {
 			/*
 			 * TODO: Could consider allowing transition to another
 			 * ESS if PMF was enabled for the association.
@@ -503,25 +493,24 @@ static int compare_scan_neighbor_results(struct wpa_supplicant *wpa_s,
 			continue;
 		}
 
-		if (res->level < bss->level && res->level < -80) {
+		if (target->level < bss->level && target->level < -80) {
 			wpa_printf(MSG_DEBUG, "Candidate BSS " MACSTR
 				   " (pref %d) does not have sufficient signal level (%d)",
 				   MAC2STR(nei->bssid),
 				   nei->preference_present ? nei->preference :
 				   -1,
-				   res->level);
+				   target->level);
 			continue;
 		}
 
 		wpa_printf(MSG_DEBUG,
-			   "WNM: Found an acceptable prefed transition candidate BSS "
+			   "WNM: Found an acceptable preferred transition candidate BSS "
 			   MACSTR " (RSSI %d)",
-			   MAC2STR(nei->bssid), res->level);
-		os_memcpy(bssid_to_connect, nei->bssid, ETH_ALEN);
-		return 1;
+			   MAC2STR(nei->bssid), target->level);
+		return target;
 	}
 
-	return 0;
+	return NULL;
 }
 
 
@@ -537,6 +526,11 @@ static void wnm_send_bss_transition_mgmt_resp(
 	wpa_printf(MSG_DEBUG, "WNM: Send BSS Transition Management Response "
 		   "to " MACSTR " dialog_token=%u status=%u delay=%d",
 		   MAC2STR(wpa_s->bssid), dialog_token, status, delay);
+	if (!wpa_s->current_bss) {
+		wpa_printf(MSG_DEBUG,
+			   "WNM: Current BSS not known - drop response");
+		return;
+	}
 
 	mgmt = (struct ieee80211_mgmt *) buf;
 	os_memset(&buf, 0, sizeof(buf));
@@ -572,56 +566,69 @@ static void wnm_send_bss_transition_mgmt_resp(
 }
 
 
-static void wnm_scan_response(struct wpa_supplicant *wpa_s,
-			      struct wpa_scan_results *scan_res)
+int wnm_scan_process(struct wpa_supplicant *wpa_s)
 {
-	u8 bssid[ETH_ALEN];
+	struct wpa_bss *bss;
+	struct wpa_ssid *ssid = wpa_s->current_ssid;
+	enum bss_trans_mgmt_status_code status = WNM_BSS_TM_REJECT_UNSPECIFIED;
 
-	if (scan_res == NULL) {
-		wpa_printf(MSG_ERROR, "Scan result is NULL");
-		goto send_bss_resp_fail;
+	if (!wpa_s->wnm_neighbor_report_elements)
+		return 0;
+
+	if (os_reltime_before(&wpa_s->wnm_cand_valid_until,
+			      &wpa_s->scan_trigger_time)) {
+		wpa_printf(MSG_DEBUG, "WNM: Previously stored BSS transition candidate list is not valid anymore - drop it");
+		wnm_deallocate_memory(wpa_s);
+		return 0;
+	}
+
+	if (!wpa_s->current_bss ||
+	    os_memcmp(wpa_s->wnm_cand_from_bss, wpa_s->current_bss->bssid,
+		      ETH_ALEN) != 0) {
+		wpa_printf(MSG_DEBUG, "WNM: Stored BSS transition candidate list not from the current BSS - ignore it");
+		return 0;
 	}
 
 	/* Compare the Neighbor Report and scan results */
-	if (compare_scan_neighbor_results(wpa_s, scan_res,
-					  wpa_s->wnm_neighbor_report_elements,
-					  wpa_s->wnm_num_neighbor_report,
-					  bssid) == 1) {
-		/* Associate to the network */
-		struct wpa_bss *bss;
-		struct wpa_ssid *ssid = wpa_s->current_ssid;
-
-		bss = wpa_bss_get_bssid(wpa_s, bssid);
+	bss = compare_scan_neighbor_results(wpa_s);
 	if (!bss) {
-			wpa_printf(MSG_DEBUG, "WNM: Target AP not found from "
-				   "BSS table");
+		wpa_printf(MSG_DEBUG, "WNM: No BSS transition candidate match found");
+		status = WNM_BSS_TM_REJECT_NO_SUITABLE_CANDIDATES;
 		goto send_bss_resp_fail;
 	}
 
+	/* Associate to the network */
 	/* Send the BSS Management Response - Accept */
 	if (wpa_s->wnm_reply) {
+		wpa_s->wnm_reply = 0;
 		wnm_send_bss_transition_mgmt_resp(wpa_s,
 						  wpa_s->wnm_dialog_token,
 						  WNM_BSS_TM_ACCEPT,
-						  0, bssid);
+						  0, bss->bssid);
+	}
+
+	if (bss == wpa_s->current_bss) {
+		wpa_printf(MSG_DEBUG,
+			   "WNM: Already associated with the preferred candidate");
+		return 1;
 	}
 
 	wpa_s->reassociate = 1;
 	wpa_supplicant_connect(wpa_s, bss, ssid);
 	wnm_deallocate_memory(wpa_s);
-		return;
-	}
+	return 1;
 
 	/* Send reject response for all the failures */
 send_bss_resp_fail:
-	wnm_deallocate_memory(wpa_s);
 	if (wpa_s->wnm_reply) {
+		wpa_s->wnm_reply = 0;
 		wnm_send_bss_transition_mgmt_resp(wpa_s,
 						  wpa_s->wnm_dialog_token,
-						  WNM_BSS_TM_REJECT_UNSPECIFIED,
-						  0, NULL);
+						  status, 0, NULL);
 	}
-	return;
+	wnm_deallocate_memory(wpa_s);
+
+	return 0;
 }
 
 
@@ -785,8 +792,8 @@ static void ieee802_11_rx_bss_trans_mgmt_req(struct wpa_supplicant *wpa_s,
 		wpa_s->wnm_cand_valid_until.sec +=
 			wpa_s->wnm_cand_valid_until.usec / 1000000;
 		wpa_s->wnm_cand_valid_until.usec %= 1000000;
+		os_memcpy(wpa_s->wnm_cand_from_bss, wpa_s->bssid, ETH_ALEN);
 
-		wpa_s->scan_res_handler = wnm_scan_response;
 		wpa_supplicant_req_scan(wpa_s, 0, 0);
 	} else if (reply) {
 		enum bss_trans_mgmt_status_code status;

wpa_supplicant/wnm_sta.h

@@ -58,4 +58,18 @@ int wnm_send_bss_transition_mgmt_query(struct wpa_supplicant *wpa_s,
 				       u8 query_reason);
 void wnm_deallocate_memory(struct wpa_supplicant *wpa_s);
 
+
+#ifdef CONFIG_WNM
+
+int wnm_scan_process(struct wpa_supplicant *wpa_s);
+
+#else /* CONFIG_WNM */
+
+static inline int wnm_scan_process(struct wpa_supplicant *wpa_s)
+{
+	return 0;
+}
+
+#endif /* CONFIG_WNM */
+
 #endif /* WNM_STA_H */

wpa_supplicant/wpa_supplicant_i.h

@@ -872,6 +872,7 @@ struct wpa_supplicant {
 	u8 wnm_bss_termination_duration[12];
 	struct neighbor_report *wnm_neighbor_report_elements;
 	struct os_reltime wnm_cand_valid_until;
+	u8 wnm_cand_from_bss[ETH_ALEN];
 #endif /* CONFIG_WNM */
 
 #ifdef CONFIG_TESTING_GET_GTK