OWE: Use PMKSA caching if available with driver AP MLME

If a matching PMKSA cache entry is present for an OWE client, use it and
do not go through DH while processing Association Rquest frame.
Association Response frame will identify the PMKID in such a case and DH
parameters won't be present.

Signed-off-by: Ashok Ponnaiah <aponnaia@codeaurora.org>

src/ap/drv_callbacks.c

@@ -530,7 +530,8 @@ skip_wpa_check:
 
 		npos = owe_auth_req_process(hapd, sta,
 					    elems.owe_dh, elems.owe_dh_len,
-					    p, &reason);
+					    p, sizeof(buf) - (p - buf),
+					    &reason);
 		if (npos)
 			p = npos;
 		if (!npos &&

src/ap/ieee802_11.c

@@ -2990,10 +2990,18 @@ done:
 #ifdef CONFIG_OWE
 u8 * owe_auth_req_process(struct hostapd_data *hapd, struct sta_info *sta,
 			  const u8 *owe_dh, u8 owe_dh_len,
-			  u8 *owe_buf, u16 *reason)
+			  u8 *owe_buf, size_t owe_buf_len, u16 *reason)
 {
 	struct wpabuf *pub;
 
+	if (wpa_auth_sta_get_pmksa(sta->wpa_sm)) {
+		wpa_printf(MSG_DEBUG, "OWE: Using PMKSA caching");
+		owe_buf = wpa_auth_write_assoc_resp_owe(sta->wpa_sm, owe_buf,
+							owe_buf_len, NULL, 0);
+		*reason = WLAN_STATUS_SUCCESS;
+		return owe_buf;
+	}
+
 	*reason = owe_process_assoc_req(hapd, sta, owe_dh, owe_dh_len);
 	if (*reason != WLAN_STATUS_SUCCESS)
 		return NULL;

src/ap/ieee802_11.h

@@ -144,7 +144,7 @@ void ieee802_11_finish_fils_auth(struct hostapd_data *hapd,
 				 const u8 *msk, size_t msk_len);
 u8 * owe_auth_req_process(struct hostapd_data *hapd, struct sta_info *sta,
 			  const u8 *owe_dh, u8 owe_dh_len,
-			  u8 *owe_buf, u16 *reason);
+			  u8 *owe_buf, size_t owe_buf_len, u16 *reason);
 void fils_hlp_timeout(void *eloop_ctx, void *eloop_data);
 void fils_hlp_finish_assoc(struct hostapd_data *hapd, struct sta_info *sta);
 void handle_auth_fils(struct hostapd_data *hapd, struct sta_info *sta,