AP MLD: Reduce struct mld_link_info size

Replace the fixed length maximum buffer size for STA profile with
dynamically allocated buffers for active links. This reduces struct
mld_link_info size by almost 16 kB and drops the per-STA information in
struct sta_info to a more reasonable size to avoid the almost 10x
increase from MLO support.

In addition, free the resp_sta_profile buffers as soon as the ML element
has bee generated for (Re)Association Response frame since those buffers
are not needed after that.

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

src/ap/beacon.c

@@ -617,6 +617,19 @@ struct probe_resp_params {
 #endif /* CONFIG_IEEE80211AX */
 };
 
+
+static void hostapd_free_probe_resp_params(struct probe_resp_params *params)
+{
+#ifdef CONFIG_IEEE80211BE
+	if (!params)
+		return;
+	ap_sta_free_sta_profile(params->mld_info);
+	os_free(params->mld_info);
+	params->mld_info = NULL;
+#endif /* CONFIG_IEEE80211BE */
+}
+
+
 static size_t hostapd_probe_resp_elems_len(struct hostapd_data *hapd,
 					   struct probe_resp_params *params)
 {
@@ -955,6 +968,7 @@ static void hostapd_fill_probe_resp_ml_params(struct hostapd_data *hapd,
 		size_t buflen;
 		u8 mld_link_id = link->mld_link_id;
 		u8 *epos;
+		u8 buf[EHT_ML_MAX_STA_PROF_LEN];
 
 		/*
 		 * Set mld_ap iff the ML probe request explicitly
@@ -984,7 +998,7 @@ static void hostapd_fill_probe_resp_ml_params(struct hostapd_data *hapd,
 		buflen = MAX_PROBERESP_LEN;
 		buflen += hostapd_probe_resp_elems_len(link, &sta_info_params);
 
-		if (buflen > sizeof(link_info->resp_sta_profile)) {
+		if (buflen > EHT_ML_MAX_STA_PROF_LEN) {
 			wpa_printf(MSG_DEBUG,
 				   "MLD: Not including link %d in ML probe response (%zu bytes is too long)",
 				   mld_link_id, buflen);
@@ -996,18 +1010,21 @@ static void hostapd_fill_probe_resp_ml_params(struct hostapd_data *hapd,
 		 * various other things.
 		 */
 		link_info->valid = true;
-		epos = link_info->resp_sta_profile;
+		epos = buf;
 
 		/* Capabilities is the only fixed parameter */
-		WPA_PUT_LE16(link_info->resp_sta_profile,
-			     hostapd_own_capab_info(hapd));
+		WPA_PUT_LE16(epos, hostapd_own_capab_info(hapd));
+		epos += 2;
 
 		epos = hostapd_probe_resp_fill_elems(
-			link, &sta_info_params,
-			link_info->resp_sta_profile + 2,
-			sizeof(link_info->resp_sta_profile) - 2);
-		link_info->resp_sta_profile_len =
-			epos - link_info->resp_sta_profile;
+			link, &sta_info_params, epos,
+			EHT_ML_MAX_STA_PROF_LEN - 2);
+		link_info->resp_sta_profile_len = epos - buf;
+		os_free(link_info->resp_sta_profile);
+		link_info->resp_sta_profile = os_memdup(
+			buf, link_info->resp_sta_profile_len);
+		if (!link_info->resp_sta_profile)
+			link_info->resp_sta_profile_len = 0;
 		os_memcpy(link_info->local_addr, link->own_addr, ETH_ALEN);
 
 		wpa_printf(MSG_DEBUG,
@@ -1026,7 +1043,7 @@ static void hostapd_fill_probe_resp_ml_params(struct hostapd_data *hapd,
 	return;
 
 fail:
-	os_free(params->mld_info);
+	hostapd_free_probe_resp_params(params);
 	params->mld_ap = NULL;
 	params->mld_info = NULL;
 }
@@ -1584,7 +1601,7 @@ void handle_probe_req(struct hostapd_data *hapd,
 
 	hostapd_gen_probe_resp(hapd, &params);
 
-	os_free(params.mld_info);
+	hostapd_free_probe_resp_params(&params);
 
 	if (!params.resp)
 		return;

src/ap/ieee802_11.c

@@ -3078,6 +3078,7 @@ static void handle_auth(struct hostapd_data *hapd,
 
 #ifdef CONFIG_IEEE80211BE
 	if (auth_transaction == 1) {
+		ap_sta_free_sta_profile(&sta->mld_info);
 		os_memset(&sta->mld_info, 0, sizeof(sta->mld_info));
 
 		if (mld_sta) {
@@ -4319,22 +4320,23 @@ static int check_assoc_ies(struct hostapd_data *hapd, struct sta_info *sta,
 
 #ifdef CONFIG_IEEE80211BE
 
-static size_t ieee80211_ml_build_assoc_resp(struct hostapd_data *hapd,
-					    u16 status_code,
-					    u8 *buf, size_t buflen)
+static void ieee80211_ml_build_assoc_resp(struct hostapd_data *hapd,
+					  struct mld_link_info *link)
 {
+	u8 buf[EHT_ML_MAX_STA_PROF_LEN];
 	u8 *p = buf;
+	size_t buflen = sizeof(buf);
 
 	/* Capability Info */
 	WPA_PUT_LE16(p, hostapd_own_capab_info(hapd));
 	p += 2;
 
 	/* Status Code */
-	WPA_PUT_LE16(p, status_code);
+	WPA_PUT_LE16(p, link->status);
 	p += 2;
 
-	if (status_code != WLAN_STATUS_SUCCESS)
-		return p - buf;
+	if (link->status != WLAN_STATUS_SUCCESS)
+		goto out;
 
 	/* AID is not included */
 	p = hostapd_eid_supp_rates(hapd, p);
@@ -4372,7 +4374,10 @@ static size_t ieee80211_ml_build_assoc_resp(struct hostapd_data *hapd,
 		p += wpabuf_len(hapd->conf->assocresp_elements);
 	}
 
-	return p - buf;
+out:
+	os_free(link->resp_sta_profile);
+	link->resp_sta_profile = os_memdup(buf, p - buf);
+	link->resp_sta_profile_len = link->resp_sta_profile ? p - buf : 0;
 }
 
 
@@ -4386,6 +4391,7 @@ static void ieee80211_ml_process_link(struct hostapd_data *hapd,
 	struct wpabuf *mlbuf = NULL;
 	struct sta_info *sta = NULL;
 	u16 status = WLAN_STATUS_SUCCESS;
+	int i;
 
 	wpa_printf(MSG_DEBUG, "MLD: link: link_id=%u, peer=" MACSTR,
 		   hapd->mld_link_id, MAC2STR(link->peer_addr));
@@ -4435,6 +4441,12 @@ static void ieee80211_ml_process_link(struct hostapd_data *hapd,
 	sta->mld_assoc_link_id = origin_sta->mld_assoc_link_id;
 
 	os_memcpy(&sta->mld_info, &origin_sta->mld_info, sizeof(sta->mld_info));
+	for (i = 0; i < MAX_NUM_MLD_LINKS; i++) {
+		struct mld_link_info *li = &sta->mld_info.links[i];
+
+		li->resp_sta_profile = NULL;
+		li->resp_sta_profile_len = 0;
+	}
 
 	/*
 	 * Get the AID from the station on which the association was performed,
@@ -4485,10 +4497,7 @@ out:
 	if (sta && status != WLAN_STATUS_SUCCESS)
 		ap_free_sta(hapd, sta);
 
-	link->resp_sta_profile_len =
-		ieee80211_ml_build_assoc_resp(hapd, link->status,
-					      link->resp_sta_profile,
-					      sizeof(link->resp_sta_profile));
+	ieee80211_ml_build_assoc_resp(hapd, link);
 }
 
 
@@ -4552,19 +4561,11 @@ static void hostapd_process_assoc_ml_info(struct hostapd_data *hapd,
 				   "MLD: No link match for link_id=%u", i);
 
 			link->status = WLAN_STATUS_UNSPECIFIED_FAILURE;
-			link->resp_sta_profile_len =
-				ieee80211_ml_build_assoc_resp(
-					hapd, link->status,
-					link->resp_sta_profile,
-					sizeof(link->resp_sta_profile));
+			ieee80211_ml_build_assoc_resp(hapd, link);
 		} else if (tx_link_status != WLAN_STATUS_SUCCESS) {
 			/* TX link rejected the connection */
 			link->status = WLAN_STATUS_DENIED_TX_LINK_NOT_ACCEPTED;
-			link->resp_sta_profile_len =
-				ieee80211_ml_build_assoc_resp(
-					hapd, link->status,
-					link->resp_sta_profile,
-					sizeof(link->resp_sta_profile));
+			ieee80211_ml_build_assoc_resp(hapd, link);
 		} else {
 			ieee80211_ml_process_link(iface->bss[0], sta, link,
 						  ies, ies_len, reassoc);

src/ap/ieee802_11_eht.c

@@ -583,6 +583,9 @@ static u8 * hostapd_eid_eht_basic_ml_common(struct hostapd_data *hapd,
 		/* BSS Parameters Change Count */
 		wpabuf_put_u8(buf, hapd->eht_mld_bss_param_change);
 
+		if (!link->resp_sta_profile)
+			continue;
+
 		/* Fragment the sub element if needed */
 		if (total_len <= 255) {
 			wpabuf_put_data(buf, link->resp_sta_profile,
@@ -784,6 +787,7 @@ u8 * hostapd_eid_eht_ml_assoc(struct hostapd_data *hapd, struct sta_info *info,
 
 	eid = hostapd_eid_eht_basic_ml_common(hapd, eid, &info->mld_info,
 					      false);
+	ap_sta_free_sta_profile(&info->mld_info);
 	return hostapd_eid_eht_reconf_ml(hapd, eid);
 }
 

src/ap/sta_info.c

@@ -350,6 +350,7 @@ void ap_free_sta(struct hostapd_data *hapd, struct sta_info *sta)
 #ifdef CONFIG_INTERWORKING
 	if (sta->gas_dialog) {
 		int i;
+
 		for (i = 0; i < GAS_DIALOG_MAX; i++)
 			gas_serv_dialog_clear(&sta->gas_dialog[i]);
 		os_free(sta->gas_dialog);
@@ -420,6 +421,10 @@ void ap_free_sta(struct hostapd_data *hapd, struct sta_info *sta)
 
 	os_free(sta->ifname_wds);
 
+#ifdef CONFIG_IEEE80211BE
+	ap_sta_free_sta_profile(&sta->mld_info);
+#endif /* CONFIG_IEEE80211BE */
+
 #ifdef CONFIG_TESTING_OPTIONS
 	os_free(sta->sae_postponed_commit);
 	forced_memzero(sta->last_tk, WPA_TK_MAX_LEN);
@@ -1791,3 +1796,19 @@ int ap_sta_re_add(struct hostapd_data *hapd, struct sta_info *sta)
 	sta->added_unassoc = 1;
 	return 0;
 }
+
+
+#ifdef CONFIG_IEEE80211BE
+void ap_sta_free_sta_profile(struct mld_info *info)
+{
+	int i;
+
+	if (!info)
+		return;
+
+	for (i = 0; i < MAX_NUM_MLD_LINKS; i++) {
+		os_free(info->links[i].resp_sta_profile);
+		info->links[i].resp_sta_profile = NULL;
+	}
+}
+#endif /* CONFIG_IEEE80211BE */

src/ap/sta_info.h

@@ -93,7 +93,7 @@ struct mld_info {
 
 		u16 status;
 		size_t resp_sta_profile_len;
-		u8 resp_sta_profile[EHT_ML_MAX_STA_PROF_LEN];
+		u8 *resp_sta_profile;
 
 		const u8 *rsne, *rsnxe;
 	} links[MAX_NUM_MLD_LINKS];
@@ -438,4 +438,6 @@ static inline void ap_sta_set_mld(struct sta_info *sta, bool mld)
 #endif /* CONFIG_IEEE80211BE */
 }
 
+void ap_sta_free_sta_profile(struct mld_info *info);
+
 #endif /* STA_INFO_H */