[PATCH] wpa_supplicant: Allow vifs to scan only current channel.

[greearb at candelatech.com]

From: Ben Greear <greearb at candelatech.com>

If a VIF is already associated, then only scan on the associated
frequency if user requests such.  This is a big help when using
lots of virtual stations.

Signed-hostap: Ben Greear <greearb at candelatech.com>
---
:100644 100644 28c40a1... 0dd951c... M	wpa_supplicant/config.c
:100644 100644 ef95650... 60c6f59... M	wpa_supplicant/config.h
:100644 100644 5ed4097... ad0a83a... M	wpa_supplicant/scan.c
:100644 100644 6aed57a... 0af8e80... M	wpa_supplicant/wpa_supplicant.conf
 wpa_supplicant/config.c            |    2 ++
 wpa_supplicant/config.h            |    7 +++++++
 wpa_supplicant/scan.c              |   17 +++++++++++++++--
 wpa_supplicant/wpa_supplicant.conf |   13 +++++++++++++
 4 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/wpa_supplicant/config.c b/wpa_supplicant/config.c
index 28c40a1..0dd951c 100644
--- a/wpa_supplicant/config.c
+++ b/wpa_supplicant/config.c
@@ -2585,6 +2585,7 @@ struct wpa_config * wpa_config_alloc_empty(const char *ctrl_interface,
 	config->bss_expiration_scan_count = DEFAULT_BSS_EXPIRATION_SCAN_COUNT;
 	config->max_num_sta = DEFAULT_MAX_NUM_STA;
 	config->access_network_type = DEFAULT_ACCESS_NETWORK_TYPE;
+	config->scan_cur_freq = DEFAULT_SCAN_CUR_FREQ;
 	config->wmm_ac_params[0] = ac_be;
 	config->wmm_ac_params[1] = ac_bk;
 	config->wmm_ac_params[2] = ac_vi;
@@ -3040,6 +3041,7 @@ static const struct global_parse_data global_fields[] = {
 	{ STR(pcsc_pin), 0 },
 	{ STR(driver_param), 0 },
 	{ FUNC(freq_list), 0 },
+	{ INT(scan_cur_freq), 0 },
 	{ INT(dot11RSNAConfigPMKLifetime), 0 },
 	{ INT(dot11RSNAConfigPMKReauthThreshold), 0 },
 	{ INT(dot11RSNAConfigSATimeout), 0 },
diff --git a/wpa_supplicant/config.h b/wpa_supplicant/config.h
index ef95650..60c6f59 100644
--- a/wpa_supplicant/config.h
+++ b/wpa_supplicant/config.h
@@ -21,6 +21,7 @@
 #define DEFAULT_P2P_INTRA_BSS 1
 #define DEFAULT_P2P_GO_MAX_INACTIVITY (5 * 60)
 #define DEFAULT_BSS_MAX_COUNT 200
+#define DEFAULT_SCAN_CUR_FREQ 0
 #define DEFAULT_BSS_EXPIRATION_AGE 180
 #define DEFAULT_BSS_EXPIRATION_SCAN_COUNT 2
 #define DEFAULT_MAX_NUM_STA 128
@@ -655,6 +656,12 @@ struct wpa_config {
 	 */
 	int *freq_list;
 
+
+	/* If true, attempt to scan only the current channel if any other
+	 * VIFs on this radio are already associated on a particular channel.
+	 */
+	int scan_cur_freq;
+	 
 	/**
 	 * changed_parameters - Bitmap of changed parameters since last update
 	 */
diff --git a/wpa_supplicant/scan.c b/wpa_supplicant/scan.c
index 5ed4097..ad0a83a 100644
--- a/wpa_supplicant/scan.c
+++ b/wpa_supplicant/scan.c
@@ -476,6 +476,7 @@ static int non_p2p_network_enabled(struct wpa_supplicant *wpa_s)
 	return 0;
 }
 
+#endif /* CONFIG_P2P */
 
 /*
  * Find the operating frequency of any other virtual interface that is using
@@ -515,8 +516,6 @@ static int shared_vif_oper_freq(struct wpa_supplicant *wpa_s)
 	return 0;
 }
 
-#endif /* CONFIG_P2P */
-
 
 void wpa_supplicant_scan(void *eloop_ctx, void *timeout_ctx)
 {
@@ -757,6 +756,20 @@ ssid_list_set:
 		int_array_concat(&params.freqs, wpa_s->conf->freq_list);
 	}
 
+	/* Use current associated channel? */
+	if (wpa_s->conf->scan_cur_freq && !params.freqs) {
+		int freq = shared_vif_oper_freq(wpa_s);
+		if (freq > 0) {
+			wpa_dbg(wpa_s, MSG_DEBUG, "Scan only the current "
+				"operating channel (%d MHz) since "
+				"scan_cur_freq is enabled.", freq);
+			params.freqs = os_zalloc(sizeof(int) * 2);
+			if (params.freqs)
+				params.freqs[0] = freq;
+		}
+	}
+
+
 	params.filter_ssids = wpa_supplicant_build_filter_ssids(
 		wpa_s->conf, &params.num_filter_ssids);
 	if (extra_ie) {
diff --git a/wpa_supplicant/wpa_supplicant.conf b/wpa_supplicant/wpa_supplicant.conf
index 6aed57a..0af8e80 100644
--- a/wpa_supplicant/wpa_supplicant.conf
+++ b/wpa_supplicant/wpa_supplicant.conf
@@ -527,6 +527,11 @@ fast_reauth=1
 # This can also be set on the outside of the network block.  In this case,
 # it limits the frequencies that will be scanned.
 #
+# scan_cur_freq:  Scan current frequency.
+# 0:  Scan all available frequencies. (Default)
+# 1:  Scan current operating frequency if another VIF on the same radio
+#     is already associated.
+#
 # bgscan: Background scanning
 # wpa_supplicant behavior for background scanning can be specified by
 # configuring a bgscan module. These modules are responsible for requesting
@@ -1241,3 +1246,11 @@ freq_list=5180
 network={
 	key_mgmt=NONE
 }
+
+
+# Example config file that will scan on existing frequency if
+# another VIF on the same radio is already associated.
+scan_cur_freq=1
+network={
+	key_mgmt=NONE
+}
-- 
1.7.3.4