SAE: Add support for Anti-Clogging mechanism

hostapd can now be configured to use anti-clogging mechanism based on
the new sae_anti_clogging_threshold parameter (which is
dot11RSNASAEAntiCloggingThreshold in the standard). The token is
generated using a temporary key and the peer station's MAC address.
wpa_supplicant will re-try SAE authentication with the token included if
commit message is rejected with a token request.

Signed-hostap: Jouni Malinen <j@w1.fi>

src/ap/hostapd.h

@@ -192,6 +192,12 @@ struct hostapd_data {
 #ifdef CONFIG_SQLITE
 	struct hostapd_eap_user tmp_eap_user;
 #endif /* CONFIG_SQLITE */
+
+#ifdef CONFIG_SAE
+	/** Key used for generating SAE anti-clogging tokens */
+	u8 sae_token_key[8];
+	os_time_t last_sae_token_key_update;
+#endif /* CONFIG_SAE */
 };