Provide option to configure BSSID hint for a network

This exposes user configurable option to set bssid_hint for a network.
bssid_hint indicates which BSS has been found a suitable candidate for
initial association for drivers that use driver/firmware-based BSS
selection. Unlike the bssid parameter, bssid_hint does not limit the
driver from selecting other BSSs in the ESS.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

wpa_supplicant/config.c

@@ -397,6 +397,50 @@ static char * wpa_config_write_bssid(const struct parse_data *data,
 #endif /* NO_CONFIG_WRITE */
 
 
+static int wpa_config_parse_bssid_hint(const struct parse_data *data,
+				       struct wpa_ssid *ssid, int line,
+				       const char *value)
+{
+	if (value[0] == '\0' || os_strcmp(value, "\"\"") == 0 ||
+	    os_strcmp(value, "any") == 0) {
+		ssid->bssid_hint_set = 0;
+		wpa_printf(MSG_MSGDUMP, "BSSID hint any");
+		return 0;
+	}
+	if (hwaddr_aton(value, ssid->bssid_hint)) {
+		wpa_printf(MSG_ERROR, "Line %d: Invalid BSSID hint '%s'.",
+			   line, value);
+		return -1;
+	}
+	ssid->bssid_hint_set = 1;
+	wpa_hexdump(MSG_MSGDUMP, "BSSID hint", ssid->bssid_hint, ETH_ALEN);
+	return 0;
+}
+
+
+#ifndef NO_CONFIG_WRITE
+static char * wpa_config_write_bssid_hint(const struct parse_data *data,
+					  struct wpa_ssid *ssid)
+{
+	char *value;
+	int res;
+
+	if (!ssid->bssid_hint_set)
+		return NULL;
+
+	value = os_malloc(20);
+	if (!value)
+		return NULL;
+	res = os_snprintf(value, 20, MACSTR, MAC2STR(ssid->bssid_hint));
+	if (os_snprintf_error(20, res)) {
+		os_free(value);
+		return NULL;
+	}
+	return value;
+}
+#endif /* NO_CONFIG_WRITE */
+
+
 static int wpa_config_parse_bssid_blacklist(const struct parse_data *data,
 					    struct wpa_ssid *ssid, int line,
 					    const char *value)
@@ -2028,6 +2072,7 @@ static const struct parse_data ssid_fields[] = {
 	{ STR_RANGE(ssid, 0, SSID_MAX_LEN) },
 	{ INT_RANGE(scan_ssid, 0, 1) },
 	{ FUNC(bssid) },
+	{ FUNC(bssid_hint) },
 	{ FUNC(bssid_blacklist) },
 	{ FUNC(bssid_whitelist) },
 	{ FUNC_KEY(psk) },

wpa_supplicant/config_file.c

@@ -503,6 +503,17 @@ static void write_bssid(FILE *f, struct wpa_ssid *ssid)
 }
 
 
+static void write_bssid_hint(FILE *f, struct wpa_ssid *ssid)
+{
+	char *value = wpa_config_get(ssid, "bssid_hint");
+
+	if (!value)
+		return;
+	fprintf(f, "\tbssid_hint=%s\n", value);
+	os_free(value);
+}
+
+
 static void write_psk(FILE *f, struct wpa_ssid *ssid)
 {
 	char *value;
@@ -713,6 +724,7 @@ static void wpa_config_write_network(FILE *f, struct wpa_ssid *ssid)
 	STR(ssid);
 	INT(scan_ssid);
 	write_bssid(f, ssid);
+	write_bssid_hint(f, ssid);
 	write_str(f, "bssid_blacklist", ssid);
 	write_str(f, "bssid_whitelist", ssid);
 	write_psk(f, ssid);

wpa_supplicant/config_ssid.h

@@ -146,6 +146,19 @@ struct wpa_ssid {
 	 */
 	int bssid_set;
 
+	/**
+	 * bssid_hint - BSSID hint
+	 *
+	 * If set, this is configured to the driver as a preferred initial BSSID
+	 * while connecting to this network.
+	 */
+	u8 bssid_hint[ETH_ALEN];
+
+	/**
+	 * bssid_hint_set - Whether BSSID hint is configured for this network
+	 */
+	int bssid_hint_set;
+
 	/**
 	 * go_p2p_dev_addr - GO's P2P Device Address or all zeros if not set
 	 */

wpa_supplicant/wpa_supplicant.c

@@ -2681,6 +2681,9 @@ static void wpas_start_assoc_cb(struct wpa_radio_work *work, int deinit)
 		params.freq_hint = bss->freq;
 		params.pbss = bss_is_pbss(bss);
 	} else {
+		if (ssid->bssid_hint_set)
+			params.bssid_hint = ssid->bssid_hint;
+
 		params.ssid = ssid->ssid;
 		params.ssid_len = ssid->ssid_len;
 		params.pbss = (ssid->pbss != 2) ? ssid->pbss : 0;