Added support for opportunistic key caching (OKC)

This allows hostapd to share the PMKSA caches internally when multiple
BSSes or radios are being controlled by the same hostapd process.

hostapd/ChangeLog

@@ -12,6 +12,7 @@ ChangeLog for hostapd
 	* added fragmentation support for EAP-TNC
 	* added support for fragmenting EAP-TTLS/PEAP/FAST Phase 2 (tunneled)
 	  data
+	* added support for opportunistic key caching (OKC)
 
 2008-02-22 - v0.6.3
 	* fixed Reassociation Response callback processing when using internal

hostapd/config.c

@@ -1935,6 +1935,8 @@ struct hostapd_config * hostapd_config_read(const char *fname)
 #endif /* CONFIG_IEEE80211W */
 		} else if (os_strcmp(buf, "max_listen_interval") == 0) {
 			bss->max_listen_interval = atoi(pos);
+		} else if (os_strcmp(buf, "okc") == 0) {
+			bss->okc = atoi(pos);
 		} else {
 			printf("Line %d: unknown configuration item '%s'\n",
 			       line, buf);

hostapd/config.h

@@ -270,6 +270,8 @@ struct hostapd_bss_config {
 	 * denied with status code 51.
 	 */
 	u16 max_listen_interval;
+
+	int okc; /* Opportunistic Key Caching */
 };
 
 

hostapd/hostapd.c

@@ -298,6 +298,7 @@ static void hostapd_wpa_auth_conf(struct hostapd_bss_config *conf,
 	wconf->eapol_version = conf->eapol_version;
 	wconf->peerkey = conf->peerkey;
 	wconf->wme_enabled = conf->wme_enabled;
+	wconf->okc = conf->okc;
 #ifdef CONFIG_IEEE80211W
 	wconf->ieee80211w = conf->ieee80211w;
 #endif /* CONFIG_IEEE80211W */
@@ -891,6 +892,26 @@ static int hostapd_wpa_auth_for_each_sta(
 }
 
 
+static int hostapd_wpa_auth_for_each_auth(
+	void *ctx, int (*cb)(struct wpa_authenticator *sm, void *ctx),
+	void *cb_ctx)
+{
+	struct hostapd_data *ohapd;
+	size_t i, j;
+	struct hapd_interfaces *interfaces = eloop_get_user_data();
+
+	for (i = 0; i < interfaces->count; i++) {
+		for (j = 0; j < interfaces->iface[i]->num_bss; j++) {
+			ohapd = interfaces->iface[i]->bss[j];
+			if (cb(ohapd->wpa_auth, cb_ctx))
+				return 1;
+		}
+	}
+
+	return 0;
+}
+
+
 static int hostapd_wpa_auth_send_ether(void *ctx, const u8 *dst, u16 proto,
 				       const u8 *data, size_t data_len)
 {
@@ -1095,6 +1116,7 @@ static int hostapd_setup_wpa(struct hostapd_data *hapd)
 	cb.get_seqnum_igtk = hostapd_wpa_auth_get_seqnum_igtk;
 	cb.send_eapol = hostapd_wpa_auth_send_eapol;
 	cb.for_each_sta = hostapd_wpa_auth_for_each_sta;
+	cb.for_each_auth = hostapd_wpa_auth_for_each_auth;
 	cb.send_ether = hostapd_wpa_auth_send_ether;
 #ifdef CONFIG_IEEE80211R
 	cb.send_ft_action = hostapd_wpa_auth_send_ft_action;

hostapd/hostapd.conf

@@ -691,6 +691,13 @@ own_ip_addr=127.0.0.1
 # 2 = required
 #ieee80211w=0
 
+# okc: Opportunistic Key Caching (aka Proactive Key Caching)
+# Allow PMK cache to be shared opportunistically among configured interfaces
+# and BSSes (i.e., all configurations within a single hostapd process).
+# 0 = disabled (default)
+# 1 = enabled
+#okc=1
+
 
 ##### IEEE 802.11r configuration ##############################################
 

hostapd/ieee802_1x.c

@@ -873,7 +873,7 @@ void ieee802_1x_free_radius_class(struct radius_class_data *class)
 
 
 int ieee802_1x_copy_radius_class(struct radius_class_data *dst,
-				 struct radius_class_data *src)
+				 const struct radius_class_data *src)
 {
 	size_t i;
 

hostapd/ieee802_1x.h

@@ -82,6 +82,6 @@ struct radius_class_data;
 
 void ieee802_1x_free_radius_class(struct radius_class_data *class);
 int ieee802_1x_copy_radius_class(struct radius_class_data *dst,
-				 struct radius_class_data *src);
+				 const struct radius_class_data *src);
 
 #endif /* IEEE802_1X_H */

hostapd/pmksa_cache.c

@@ -208,6 +208,37 @@ void pmksa_cache_to_eapol_data(struct rsn_pmksa_cache_entry *entry,
 }
 
 
+static void pmksa_cache_link_entry(struct rsn_pmksa_cache *pmksa,
+				   struct rsn_pmksa_cache_entry *entry)
+{
+	struct rsn_pmksa_cache_entry *pos, *prev;
+
+	/* Add the new entry; order by expiration time */
+	pos = pmksa->pmksa;
+	prev = NULL;
+	while (pos) {
+		if (pos->expiration > entry->expiration)
+			break;
+		prev = pos;
+		pos = pos->next;
+	}
+	if (prev == NULL) {
+		entry->next = pmksa->pmksa;
+		pmksa->pmksa = entry;
+	} else {
+		entry->next = prev->next;
+		prev->next = entry;
+	}
+	entry->hnext = pmksa->pmkid[PMKID_HASH(entry->pmkid)];
+	pmksa->pmkid[PMKID_HASH(entry->pmkid)] = entry;
+
+	pmksa->pmksa_count++;
+	wpa_printf(MSG_DEBUG, "RSN: added PMKSA cache entry for " MACSTR,
+		   MAC2STR(entry->spa));
+	wpa_hexdump(MSG_DEBUG, "RSN: added PMKID", entry->pmkid, PMKID_LEN);
+}
+
+
 /**
  * pmksa_cache_add - Add a PMKSA cache entry
  * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
@@ -229,7 +260,7 @@ pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
 		const u8 *aa, const u8 *spa, int session_timeout,
 		struct eapol_state_machine *eapol)
 {
-	struct rsn_pmksa_cache_entry *entry, *pos, *prev;
+	struct rsn_pmksa_cache_entry *entry, *pos;
 	struct os_time now;
 
 	if (pmk_len > PMK_LEN)
@@ -265,29 +296,44 @@ pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
 		pmksa_cache_free_entry(pmksa, pmksa->pmksa);
 	}
 
-	/* Add the new entry; order by expiration time */
-	pos = pmksa->pmksa;
-	prev = NULL;
-	while (pos) {
-		if (pos->expiration > entry->expiration)
-			break;
-		prev = pos;
-		pos = pos->next;
-	}
-	if (prev == NULL) {
-		entry->next = pmksa->pmksa;
-		pmksa->pmksa = entry;
-	} else {
-		entry->next = prev->next;
-		prev->next = entry;
-	}
-	entry->hnext = pmksa->pmkid[PMKID_HASH(entry->pmkid)];
-	pmksa->pmkid[PMKID_HASH(entry->pmkid)] = entry;
+	pmksa_cache_link_entry(pmksa, entry);
 
-	pmksa->pmksa_count++;
-	wpa_printf(MSG_DEBUG, "RSN: added PMKSA cache entry for " MACSTR,
-		   MAC2STR(entry->spa));
-	wpa_hexdump(MSG_DEBUG, "RSN: added PMKID", entry->pmkid, PMKID_LEN);
+	return entry;
+}
+
+
+struct rsn_pmksa_cache_entry *
+pmksa_cache_add_okc(struct rsn_pmksa_cache *pmksa,
+		    const struct rsn_pmksa_cache_entry *old_entry,
+		    const u8 *aa, const u8 *pmkid)
+{
+	struct rsn_pmksa_cache_entry *entry;
+
+	entry = os_zalloc(sizeof(*entry));
+	if (entry == NULL)
+		return NULL;
+	os_memcpy(entry->pmkid, pmkid, PMKID_LEN);
+	os_memcpy(entry->pmk, old_entry->pmk, old_entry->pmk_len);
+	entry->pmk_len = old_entry->pmk_len;
+	entry->expiration = old_entry->expiration;
+	entry->akmp = old_entry->akmp;
+	os_memcpy(entry->spa, old_entry->spa, ETH_ALEN);
+	entry->opportunistic = 1;
+	if (old_entry->identity) {
+		entry->identity = os_malloc(old_entry->identity_len);
+		if (entry->identity) {
+			entry->identity_len = old_entry->identity_len;
+			os_memcpy(entry->identity, old_entry->identity,
+				  old_entry->identity_len);
+		}
+	}
+	ieee802_1x_copy_radius_class(&entry->radius_class,
+				     &old_entry->radius_class);
+	entry->eap_type_authsrv = old_entry->eap_type_authsrv;
+	entry->vlan_id = old_entry->vlan_id;
+	entry->opportunistic = 1;
+
+	pmksa_cache_link_entry(pmksa, entry);
 
 	return entry;
 }
@@ -346,6 +392,35 @@ struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa,
 }
 
 
+/**
+ * pmksa_cache_get_okc - Fetch a PMKSA cache entry using OKC
+ * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
+ * @spa: Supplicant address
+ * @pmkid: PMKID
+ * Returns: Pointer to PMKSA cache entry or %NULL if no match was found
+ *
+ * Use opportunistic key caching (OKC) to find a PMK for a supplicant.
+ */
+struct rsn_pmksa_cache_entry * pmksa_cache_get_okc(
+	struct rsn_pmksa_cache *pmksa, const u8 *aa, const u8 *spa,
+	const u8 *pmkid)
+{
+	struct rsn_pmksa_cache_entry *entry;
+	u8 new_pmkid[PMKID_LEN];
+
+	entry = pmksa->pmksa;
+	while (entry) {
+		if (os_memcmp(entry->spa, spa, ETH_ALEN) != 0)
+			continue;
+		rsn_pmkid(entry->pmk, entry->pmk_len, aa, spa, new_pmkid);
+		if (os_memcmp(new_pmkid, pmkid, PMKID_LEN) == 0)
+			return entry;
+		entry = entry->next;
+	}
+	return NULL;
+}
+
+
 /**
  * pmksa_cache_init - Initialize PMKSA cache
  * @free_cb: Callback function to be called when a PMKSA cache entry is freed

hostapd/pmksa_cache.h

@@ -32,6 +32,7 @@ struct rsn_pmksa_cache_entry {
 	struct radius_class_data radius_class;
 	u8 eap_type_authsrv;
 	int vlan_id;
+	int opportunistic;
 };
 
 struct rsn_pmksa_cache;
@@ -42,10 +43,17 @@ pmksa_cache_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry,
 void pmksa_cache_deinit(struct rsn_pmksa_cache *pmksa);
 struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa,
 					       const u8 *spa, const u8 *pmkid);
+struct rsn_pmksa_cache_entry * pmksa_cache_get_okc(
+	struct rsn_pmksa_cache *pmksa, const u8 *spa, const u8 *aa,
+	const u8 *pmkid);
 struct rsn_pmksa_cache_entry *
 pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
 		const u8 *aa, const u8 *spa, int session_timeout,
 		struct eapol_state_machine *eapol);
+struct rsn_pmksa_cache_entry *
+pmksa_cache_add_okc(struct rsn_pmksa_cache *pmksa,
+		    const struct rsn_pmksa_cache_entry *old_entry,
+		    const u8 *aa, const u8 *pmkid);
 void pmksa_cache_to_eapol_data(struct rsn_pmksa_cache_entry *entry,
 			       struct eapol_state_machine *eapol);
 void rsn_pmkid(const u8 *pmk, size_t pmk_len, const u8 *aa, const u8 *spa,

hostapd/wpa.c

@@ -151,6 +151,16 @@ int wpa_auth_for_each_sta(struct wpa_authenticator *wpa_auth,
 }
 
 
+int wpa_auth_for_each_auth(struct wpa_authenticator *wpa_auth,
+			   int (*cb)(struct wpa_authenticator *a, void *ctx),
+			   void *cb_ctx)
+{
+	if (wpa_auth->cb.for_each_auth == NULL)
+		return 0;
+	return wpa_auth->cb.for_each_auth(wpa_auth->cb.ctx, cb, cb_ctx);
+}
+
+
 void wpa_auth_logger(struct wpa_authenticator *wpa_auth, const u8 *addr,
 		     logger_level level, const char *txt)
 {

hostapd/wpa.h

@@ -140,6 +140,7 @@ struct wpa_auth_config {
 	int eapol_version;
 	int peerkey;
 	int wme_enabled;
+	int okc;
 #ifdef CONFIG_IEEE80211W
 	enum {
 		WPA_NO_IEEE80211W = 0,
@@ -192,6 +193,8 @@ struct wpa_auth_callbacks {
 			  size_t data_len, int encrypt);
 	int (*for_each_sta)(void *ctx, int (*cb)(struct wpa_state_machine *sm,
 						 void *ctx), void *cb_ctx);
+	int (*for_each_auth)(void *ctx, int (*cb)(struct wpa_authenticator *a,
+						  void *ctx), void *cb_ctx);
 	int (*send_ether)(void *ctx, const u8 *dst, u16 proto, const u8 *data,
 			  size_t data_len);
 #ifdef CONFIG_IEEE80211R

hostapd/wpa_auth_i.h

@@ -189,6 +189,9 @@ void __wpa_send_eapol(struct wpa_authenticator *wpa_auth,
 int wpa_auth_for_each_sta(struct wpa_authenticator *wpa_auth,
 			  int (*cb)(struct wpa_state_machine *sm, void *ctx),
 			  void *cb_ctx);
+int wpa_auth_for_each_auth(struct wpa_authenticator *wpa_auth,
+			   int (*cb)(struct wpa_authenticator *a, void *ctx),
+			   void *cb_ctx);
 
 #ifdef CONFIG_PEERKEY
 int wpa_stsl_remove(struct wpa_authenticator *wpa_auth,

hostapd/wpa_auth_ie.c

@@ -414,6 +414,25 @@ static int wpa_parse_wpa_ie_wpa(const u8 *wpa_ie, size_t wpa_ie_len,
 }
 
 
+struct wpa_auth_okc_iter_data {
+	struct rsn_pmksa_cache_entry *pmksa;
+	const u8 *aa;
+	const u8 *spa;
+	const u8 *pmkid;
+};
+
+
+static int wpa_auth_okc_iter(struct wpa_authenticator *a, void *ctx)
+{
+	struct wpa_auth_okc_iter_data *data = ctx;
+	data->pmksa = pmksa_cache_get_okc(a->pmksa, data->aa, data->spa,
+					  data->pmkid);
+	if (data->pmksa)
+		return 1;
+	return 0;
+}
+
+
 int wpa_validate_wpa_ie(struct wpa_authenticator *wpa_auth,
 			struct wpa_state_machine *sm,
 			const u8 *wpa_ie, size_t wpa_ie_len,
@@ -423,6 +442,7 @@ int wpa_validate_wpa_ie(struct wpa_authenticator *wpa_auth,
 	int ciphers, key_mgmt, res, version;
 	u32 selector;
 	size_t i;
+	const u8 *pmkid = NULL;
 
 	if (wpa_auth == NULL || sm == NULL)
 		return WPA_NOT_ENABLED;
@@ -615,22 +635,44 @@ int wpa_validate_wpa_ie(struct wpa_authenticator *wpa_auth,
 	else
 		sm->wpa = WPA_VERSION_WPA;
 
+	sm->pmksa = NULL;
 	for (i = 0; i < data.num_pmkid; i++) {
 		wpa_hexdump(MSG_DEBUG, "RSN IE: STA PMKID",
 			    &data.pmkid[i * PMKID_LEN], PMKID_LEN);
 		sm->pmksa = pmksa_cache_get(wpa_auth->pmksa, sm->addr,
 					    &data.pmkid[i * PMKID_LEN]);
 		if (sm->pmksa) {
-			wpa_auth_vlogger(wpa_auth, sm->addr, LOGGER_DEBUG,
-					 "PMKID found from PMKSA cache "
-					 "eap_type=%d vlan_id=%d",
-					 sm->pmksa->eap_type_authsrv,
-					 sm->pmksa->vlan_id);
-			os_memcpy(wpa_auth->dot11RSNAPMKIDUsed,
-				  sm->pmksa->pmkid, PMKID_LEN);
+			pmkid = sm->pmksa->pmkid;
 			break;
 		}
 	}
+	for (i = 0; sm->pmksa == NULL && wpa_auth->conf.okc &&
+		     i < data.num_pmkid; i++) {
+		struct wpa_auth_okc_iter_data idata;
+		idata.pmksa = NULL;
+		idata.aa = wpa_auth->addr;
+		idata.spa = sm->addr;
+		idata.pmkid = &data.pmkid[i * PMKID_LEN];
+		wpa_auth_for_each_auth(wpa_auth, wpa_auth_okc_iter, &idata);
+		if (idata.pmksa) {
+			wpa_auth_vlogger(wpa_auth, sm->addr, LOGGER_DEBUG,
+					 "OKC match for PMKID");
+			sm->pmksa = pmksa_cache_add_okc(wpa_auth->pmksa,
+							idata.pmksa,
+							wpa_auth->addr,
+							idata.pmkid);
+			pmkid = idata.pmkid;
+			break;
+		}
+	}
+	if (sm->pmksa) {
+		wpa_auth_vlogger(wpa_auth, sm->addr, LOGGER_DEBUG,
+				 "PMKID found from PMKSA cache "
+				 "eap_type=%d vlan_id=%d",
+				 sm->pmksa->eap_type_authsrv,
+				 sm->pmksa->vlan_id);
+		os_memcpy(wpa_auth->dot11RSNAPMKIDUsed, pmkid, PMKID_LEN);
+	}
 
 	if (sm->wpa_ie == NULL || sm->wpa_ie_len < wpa_ie_len) {
 		os_free(sm->wpa_ie);