[PATCH v2 2/3] P2P: optimize join scan freq

[Matthew Wang]

From: Matthew Wang <matthewmwang at google.com>

If the auto GO has been discovered on another interface, optimize scan
frequency by performing a single channel scan first.

Signed-off-by: Matthew Wang <matthewmwang at chromium.org>
---
 wpa_supplicant/bss.c            |  5 +++--
 wpa_supplicant/p2p_supplicant.c |  5 +++++
 wpa_supplicant/scan.c           | 27 ++++++++++++++++++++++++++-
 3 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/wpa_supplicant/bss.c b/wpa_supplicant/bss.c
index 401c5342e..5666fd027 100644
--- a/wpa_supplicant/bss.c
+++ b/wpa_supplicant/bss.c
@@ -240,7 +240,7 @@ void wpa_bss_remove(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
 /**
  * wpa_bss_get - Fetch a BSS table entry based on BSSID and SSID
  * @wpa_s: Pointer to wpa_supplicant data
- * @bssid: BSSID
+ * @bssid: BSSID, or %NULL to match any BSSID
  * @ssid: SSID
  * @ssid_len: Length of @ssid
  * Returns: Pointer to the BSS entry or %NULL if not found
@@ -252,7 +252,8 @@ struct wpa_bss * wpa_bss_get(struct wpa_supplicant *wpa_s, const u8 *bssid,
 	if (!wpa_supplicant_filter_bssid_match(wpa_s, bssid))
 		return NULL;
 	dl_list_for_each(bss, &wpa_s->bss, struct wpa_bss, list) {
-		if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0 &&
+		if ((!bssid ||
+		     os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0) &&
 		    bss->ssid_len == ssid_len &&
 		    os_memcmp(bss->ssid, ssid, ssid_len) == 0)
 			return bss;
diff --git a/wpa_supplicant/p2p_supplicant.c b/wpa_supplicant/p2p_supplicant.c
index 9f0d2faa3..dc240140d 100644
--- a/wpa_supplicant/p2p_supplicant.c
+++ b/wpa_supplicant/p2p_supplicant.c
@@ -6954,6 +6954,11 @@ static int wpas_start_p2p_client(struct wpa_supplicant *wpa_s,
 	if (params->passphrase)
 		ssid->passphrase = os_strdup(params->passphrase);
 
+	if (params->bssid_set) {
+		ssid->bssid_set = 1;
+		os_memcpy(ssid->bssid, params->bssid, ETH_ALEN);
+	}
+
 	wpa_s->show_group_started = 1;
 	wpa_s->p2p_in_invitation = 1;
 	wpa_s->p2p_retry_limit = retry_limit;
diff --git a/wpa_supplicant/scan.c b/wpa_supplicant/scan.c
index fc37c6b9a..cdf12f938 100644
--- a/wpa_supplicant/scan.c
+++ b/wpa_supplicant/scan.c
@@ -445,11 +445,36 @@ static void wpa_supplicant_optimize_freqs(
 	}
 
 	if (params->freqs == NULL && wpa_s->p2p_in_invitation) {
+		/*
+		 * Perform a single-channel scan if the GO has already been
+		 * discovered on another non-P2P interface. Note that a scan
+		 * initiated by a P2P interface (e.g. the device interface)
+		 * should already have sufficient IEs and scan results will be
+		 * fetched on interface creation in that case.
+		 */
+		if (wpa_s->p2p_in_invitation == 1 && wpa_s->current_ssid) {
+			struct wpa_supplicant *ifs;
+			struct wpa_bss *bss = NULL;
+			struct wpa_ssid *ssid = wpa_s->current_ssid;
+			u8 *bssid = ssid->bssid_set ? ssid->bssid : NULL;
+			dl_list_for_each(ifs, &wpa_s->radio->ifaces,
+					 struct wpa_supplicant, radio_list) {
+				bss = wpa_bss_get(ifs, bssid, ssid->ssid,
+						  ssid->ssid_len);
+				if (bss)
+					break;
+			}
+			if (bss && !disabled_freq(wpa_s, bss->freq)) {
+				params->freqs = os_calloc(2, sizeof(int));
+				if (params->freqs)
+					params->freqs[0] = bss->freq;
+			}
+		}
 		/*
 		 * Optimize scan based on GO information during persistent
 		 * group reinvocation
 		 */
-		if (wpa_s->p2p_in_invitation < 5 &&
+		if (params->freqs == NULL && wpa_s->p2p_in_invitation < 5 &&
 		    wpa_s->p2p_invite_go_freq > 0) {
 			wpa_dbg(wpa_s, MSG_DEBUG, "P2P: Scan only GO preferred frequency %d MHz during invitation",
 				wpa_s->p2p_invite_go_freq);
-- 
2.39.0.314.g84b9a713c41-goog