[PATCH v2] wpa_supplicant: Allow configuring scan frequencies.

[greearb at candelatech.com]

From: Ben Greear <greearb at candelatech.com>

This allows one to limit the channels that wpa_supplicant will
scan.  This is a useful addition to the freq_list configurable
in the network {} section.

Signed-hostap: Ben Greear <greearb at candelatech.com>
---
:100644 100644 f8647bb... 28c40a1... M	wpa_supplicant/config.c
:100644 100644 2f49e1e... ef95650... M	wpa_supplicant/config.h
:100644 100644 f409e98... 5ed4097... M	wpa_supplicant/scan.c
:100644 100644 0935a06... 6aed57a... M	wpa_supplicant/wpa_supplicant.conf
 wpa_supplicant/config.c            |   16 ++++++++++++++++
 wpa_supplicant/config.h            |    8 ++++++++
 wpa_supplicant/scan.c              |    7 +++++++
 wpa_supplicant/wpa_supplicant.conf |   10 ++++++++++
 4 files changed, 41 insertions(+), 0 deletions(-)

diff --git a/wpa_supplicant/config.c b/wpa_supplicant/config.c
index f8647bb..28c40a1 100644
--- a/wpa_supplicant/config.c
+++ b/wpa_supplicant/config.c
@@ -1826,6 +1826,7 @@ void wpa_config_free(struct wpa_config *config)
 	os_free(config->pssid);
 	os_free(config->p2p_pref_chan);
 	os_free(config->autoscan);
+	os_free(config->freq_list);
 	wpabuf_free(config->wps_nfc_dh_pubkey);
 	wpabuf_free(config->wps_nfc_dh_privkey);
 	wpabuf_free(config->wps_nfc_dev_pw);
@@ -2735,6 +2736,20 @@ static int wpa_global_config_parse_bin(const struct global_parse_data *data,
 	return 0;
 }
 
+static int wpa_config_process_freq_list(const struct global_parse_data *data,
+					struct wpa_config *config, int line,
+					const char *value)
+{
+	int *freqs;
+
+	freqs = wpa_config_parse_int_array(value);
+	if (freqs == NULL)
+		return -1;
+	os_free(config->freq_list);
+	config->freq_list = freqs;
+	return 0;
+}
+
 
 static int wpa_config_process_country(const struct global_parse_data *data,
 				      struct wpa_config *config, int line,
@@ -3024,6 +3039,7 @@ static const struct global_parse_data global_fields[] = {
 	{ STR(pcsc_reader), 0 },
 	{ STR(pcsc_pin), 0 },
 	{ STR(driver_param), 0 },
+	{ FUNC(freq_list), 0 },
 	{ INT(dot11RSNAConfigPMKLifetime), 0 },
 	{ INT(dot11RSNAConfigPMKReauthThreshold), 0 },
 	{ INT(dot11RSNAConfigSATimeout), 0 },
diff --git a/wpa_supplicant/config.h b/wpa_supplicant/config.h
index 2f49e1e..ef95650 100644
--- a/wpa_supplicant/config.h
+++ b/wpa_supplicant/config.h
@@ -648,6 +648,14 @@ struct wpa_config {
 	unsigned int max_num_sta;
 
 	/**
+	 * freq_list - Array of allowed scan frequencies or %NULL for all
+	 *
+	 * This is an optional zero-terminated array of frequencies in
+	 * megahertz (MHz) to allow for narrowing scanning range.
+	 */
+	int *freq_list;
+
+	/**
 	 * changed_parameters - Bitmap of changed parameters since last update
 	 */
 	unsigned int changed_parameters;
diff --git a/wpa_supplicant/scan.c b/wpa_supplicant/scan.c
index f409e98..5ed4097 100644
--- a/wpa_supplicant/scan.c
+++ b/wpa_supplicant/scan.c
@@ -750,6 +750,13 @@ ssid_list_set:
 		os_free(wpa_s->next_scan_freqs);
 	wpa_s->next_scan_freqs = NULL;
 
+	/* See if user specified frequencies..if so, scan only those */
+	if (wpa_s->conf->freq_list && !params.freqs) {
+		wpa_dbg(wpa_s, MSG_DEBUG,
+			"Optimize scan based on conf->freq_list");
+		int_array_concat(&params.freqs, wpa_s->conf->freq_list);
+	}
+
 	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 0935a06..6aed57a 100644
--- a/wpa_supplicant/wpa_supplicant.conf
+++ b/wpa_supplicant/wpa_supplicant.conf
@@ -524,6 +524,9 @@ fast_reauth=1
 # set, scan results that do not match any of the specified frequencies are not
 # considered when selecting a BSS.
 #
+# This can also be set on the outside of the network block.  In this case,
+# it limits the frequencies that will be scanned.
+#
 # bgscan: Background scanning
 # wpa_supplicant behavior for background scanning can be specified by
 # configuring a bgscan module. These modules are responsible for requesting
@@ -1231,3 +1234,10 @@ SGVsbG8gV29ybGQhCg==
 network={
 	key_mgmt=NONE
 }
+
+
+# Example config file that will only scan on channel 36.
+freq_list=5180
+network={
+	key_mgmt=NONE
+}
-- 
1.7.3.4