wpa_supplicant: Add initial roaming support

This commit adds different features from 802.11k and 802.11v
specifications to make the device ready for network assisted
roaming. It also adds initial framework for device to detect
whether it needs to move to a better AP.

Followings are added as part of this.

1. Support for sending neighbor report request and provide
   the report back to the APP.
2. Support for beacon measurement report.
3. Support for link measurement report.
4. Support for sending bss transition management query frame
   (triggered by the APP).
5. Support for bss transition management request and move
   to the candidate based on that.
6. Sending the bss transition management response.

components/wpa_supplicant/src/utils/common.c

@@ -491,3 +491,59 @@ int hwaddr_aton2(const char *txt, u8 *addr)
 
 	return pos - txt;
 }
+
+static inline int os_reltime_expired(struct os_time *now,
+				     struct os_time *ts,
+				     os_time_t timeout_secs)
+{
+	struct os_time age;
+
+	os_time_sub(now, ts, &age);
+	return (age.sec > timeout_secs) ||
+		(age.sec == timeout_secs && age.usec > 0);
+}
+
+int os_time_expired(struct os_time *now,
+		struct os_time *ts,
+		os_time_t timeout_secs)
+{
+	return os_reltime_expired(now, ts, timeout_secs);
+}
+
+u8 rssi_to_rcpi(int rssi)
+{
+	if (!rssi)
+		return 255; /* not available */
+	if (rssi < -110)
+		return 0;
+	if (rssi > 0)
+		return 220;
+	return (rssi + 110) * 2;
+}
+
+/**
+ * wpa_ssid_txt - Convert SSID to a printable string
+ * @ssid: SSID (32-octet string)
+ * @ssid_len: Length of ssid in octets
+ * Returns: Pointer to a printable string
+ *
+ * This function can be used to convert SSIDs into printable form. In most
+ * cases, SSIDs do not use unprintable characters, but IEEE 802.11 standard
+ * does not limit the used character set, so anything could be used in an SSID.
+ *
+ * This function uses a static buffer, so only one call can be used at the
+ * time, i.e., this is not re-entrant and the returned buffer must be used
+ * before calling this again.
+ */
+const char * wpa_ssid_txt(const u8 *ssid, size_t ssid_len)
+{
+	static char ssid_txt[SSID_MAX_LEN * 4 + 1];
+
+	if (ssid == NULL) {
+		ssid_txt[0] = '\0';
+		return ssid_txt;
+	}
+
+	printf_encode(ssid_txt, sizeof(ssid_txt), ssid, ssid_len);
+	return ssid_txt;
+}