hostap/src/rsn_supp/pmksa_cache.c - nest-cam/4320010/hostap - Git at Google

 /*
  * WPA Supplicant - RSN PMKSA cache
  * Copyright (c) 2004-2009, 2011-2015, Jouni Malinen <j@w1.fi>
  *
  * This software may be distributed under the terms of the BSD license.
  * See README for more details.
  */

 #include "includes.h"

 #include "common.h"
 #include "eloop.h"
 #include "eapol_supp/eapol_supp_sm.h"
 #include "wpa.h"
 #include "wpa_i.h"
 #include "pmksa_cache.h"

 #ifdef IEEE8021X_EAPOL

 static const int pmksa_cache_max_entries = 32;

 struct rsn_pmksa_cache {
 	struct rsn_pmksa_cache_entry *pmksa; /* PMKSA cache */
 	int pmksa_count; /* number of entries in PMKSA cache */
 	struct wpa_sm *sm; /* TODO: get rid of this reference(?) */

 	void (*free_cb)(struct rsn_pmksa_cache_entry *entry, void *ctx,
 			enum pmksa_free_reason reason);
 	void *ctx;
 };


 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa);


 static void _pmksa_cache_free_entry(struct rsn_pmksa_cache_entry *entry)
 {
 	bin_clear_free(entry, sizeof(*entry));
 }


 static void pmksa_cache_free_entry(struct rsn_pmksa_cache *pmksa,
 				   struct rsn_pmksa_cache_entry *entry,
 				   enum pmksa_free_reason reason)
 {
 	wpa_sm_remove_pmkid(pmksa->sm, entry->aa, entry->pmkid);
 	pmksa->pmksa_count--;
 	pmksa->free_cb(entry, pmksa->ctx, reason);
 	_pmksa_cache_free_entry(entry);
 }


 static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx)
 {
 	struct rsn_pmksa_cache *pmksa = eloop_ctx;
 	struct os_reltime now;

 	os_get_reltime(&now);
 	while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) {
 		struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
 		pmksa->pmksa = entry->next;
 		wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for "
 			   MACSTR, MAC2STR(entry->aa));
 		pmksa_cache_free_entry(pmksa, entry, PMKSA_EXPIRE);
 	}

 	pmksa_cache_set_expiration(pmksa);
 }


 static void pmksa_cache_reauth(void *eloop_ctx, void *timeout_ctx)
 {
 	struct rsn_pmksa_cache *pmksa = eloop_ctx;
 	pmksa->sm->cur_pmksa = NULL;
 	eapol_sm_request_reauth(pmksa->sm->eapol);
 }


 static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa)
 {
 	int sec;
 	struct rsn_pmksa_cache_entry *entry;
 	struct os_reltime now;

 	eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL);
 	eloop_cancel_timeout(pmksa_cache_reauth, pmksa, NULL);
 	if (pmksa->pmksa == NULL)
 		return;
 	os_get_reltime(&now);
 	sec = pmksa->pmksa->expiration - now.sec;
 	if (sec < 0)
 		sec = 0;
 	eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL);

 	entry = pmksa->sm->cur_pmksa ? pmksa->sm->cur_pmksa :
 		pmksa_cache_get(pmksa, pmksa->sm->bssid, NULL, NULL);
 	if (entry) {
 		sec = pmksa->pmksa->reauth_time - now.sec;
 		if (sec < 0)
 			sec = 0;
 		eloop_register_timeout(sec, 0, pmksa_cache_reauth, pmksa,
 				       NULL);
 	}
 }


 /**
  * pmksa_cache_add - Add a PMKSA cache entry
  * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
  * @pmk: The new pairwise master key
  * @pmk_len: PMK length in bytes, usually PMK_LEN (32)
  * @kck: Key confirmation key or %NULL if not yet derived
  * @kck_len: KCK length in bytes
  * @aa: Authenticator address
  * @spa: Supplicant address
  * @network_ctx: Network configuration context for this PMK
  * @akmp: WPA_KEY_MGMT_* used in key derivation
  * Returns: Pointer to the added PMKSA cache entry or %NULL on error
  *
  * This function create a PMKSA entry for a new PMK and adds it to the PMKSA
  * cache. If an old entry is already in the cache for the same Authenticator,
  * this entry will be replaced with the new entry. PMKID will be calculated
  * based on the PMK and the driver interface is notified of the new PMKID.
  */
 struct rsn_pmksa_cache_entry *
 pmksa_cache_add(struct rsn_pmksa_cache *pmksa, const u8 *pmk, size_t pmk_len,
 		const u8 *kck, size_t kck_len,
 		const u8 *aa, const u8 *spa, void *network_ctx, int akmp)
 {
 	struct rsn_pmksa_cache_entry *entry, *pos, *prev;
 	struct os_reltime now;

 	if (pmk_len > PMK_LEN)
 		return NULL;

 	if (wpa_key_mgmt_suite_b(akmp) && !kck)
 		return NULL;

 	entry = os_zalloc(sizeof(*entry));
 	if (entry == NULL)
 		return NULL;
 	os_memcpy(entry->pmk, pmk, pmk_len);
 	entry->pmk_len = pmk_len;
 	if (akmp == WPA_KEY_MGMT_IEEE8021X_SUITE_B_192)
 		rsn_pmkid_suite_b_192(kck, kck_len, aa, spa, entry->pmkid);
 	else if (wpa_key_mgmt_suite_b(akmp))
 		rsn_pmkid_suite_b(kck, kck_len, aa, spa, entry->pmkid);
 	else
 		rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid,
 			  wpa_key_mgmt_sha256(akmp));
 	os_get_reltime(&now);
 	entry->expiration = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime;
 	entry->reauth_time = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime *
 		pmksa->sm->dot11RSNAConfigPMKReauthThreshold / 100;
 	entry->akmp = akmp;
 	os_memcpy(entry->aa, aa, ETH_ALEN);
 	entry->network_ctx = network_ctx;

 	/* Replace an old entry for the same Authenticator (if found) with the
 	 * new entry */
 	pos = pmksa->pmksa;
 	prev = NULL;
 	while (pos) {
 		if (os_memcmp(aa, pos->aa, ETH_ALEN) == 0) {
 			if (pos->pmk_len == pmk_len &&
 			    os_memcmp_const(pos->pmk, pmk, pmk_len) == 0 &&
 			    os_memcmp_const(pos->pmkid, entry->pmkid,
 					    PMKID_LEN) == 0) {
 				wpa_printf(MSG_DEBUG, "WPA: reusing previous "
 					   "PMKSA entry");
 				os_free(entry);
 				return pos;
 			}
 			if (prev == NULL)
 				pmksa->pmksa = pos->next;
 			else
 				prev->next = pos->next;

 			/*
 			 * If OKC is used, there may be other PMKSA cache
 			 * entries based on the same PMK. These needs to be
 			 * flushed so that a new entry can be created based on
 			 * the new PMK. Only clear other entries if they have a
 			 * matching PMK and this PMK has been used successfully
 			 * with the current AP, i.e., if opportunistic flag has
 			 * been cleared in wpa_supplicant_key_neg_complete().
 			 */
 			wpa_printf(MSG_DEBUG, "RSN: Replace PMKSA entry for "
 				   "the current AP and any PMKSA cache entry "
 				   "that was based on the old PMK");
 			if (!pos->opportunistic)
 				pmksa_cache_flush(pmksa, network_ctx, pos->pmk,
 						  pos->pmk_len);
 			pmksa_cache_free_entry(pmksa, pos, PMKSA_REPLACE);
 			break;
 		}
 		prev = pos;
 		pos = pos->next;
 	}

 	if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) {
 		/* Remove the oldest entry to make room for the new entry */
 		pos = pmksa->pmksa;

 		if (pos == pmksa->sm->cur_pmksa) {
 			/*
 			 * Never remove the current PMKSA cache entry, since
 			 * it's in use, and removing it triggers a needless
 			 * deauthentication.
 			 */
 			pos = pos->next;
 			pmksa->pmksa->next = pos ? pos->next : NULL;
 		} else
 			pmksa->pmksa = pos->next;

 		if (pos) {
 			wpa_printf(MSG_DEBUG, "RSN: removed the oldest idle "
 				   "PMKSA cache entry (for " MACSTR ") to "
 				   "make room for new one",
 				   MAC2STR(pos->aa));
 			pmksa_cache_free_entry(pmksa, pos, PMKSA_FREE);
 		}
 	}

 	/* 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;
 		pmksa_cache_set_expiration(pmksa);
 	} else {
 		entry->next = prev->next;
 		prev->next = entry;
 	}
 	pmksa->pmksa_count++;
 	wpa_printf(MSG_DEBUG, "RSN: Added PMKSA cache entry for " MACSTR
 		   " network_ctx=%p", MAC2STR(entry->aa), network_ctx);
 	wpa_sm_add_pmkid(pmksa->sm, entry->aa, entry->pmkid);

 	return entry;
 }


 /**
  * pmksa_cache_flush - Flush PMKSA cache entries for a specific network
  * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
  * @network_ctx: Network configuration context or %NULL to flush all entries
  * @pmk: PMK to match for or %NYLL to match all PMKs
  * @pmk_len: PMK length
  */
 void pmksa_cache_flush(struct rsn_pmksa_cache *pmksa, void *network_ctx,
 		       const u8 *pmk, size_t pmk_len)
 {
 	struct rsn_pmksa_cache_entry *entry, *prev = NULL, *tmp;
 	int removed = 0;

 	entry = pmksa->pmksa;
 	while (entry) {
 		if ((entry->network_ctx == network_ctx ||
 		     network_ctx == NULL) &&
 		    (pmk == NULL ||
 		     (pmk_len == entry->pmk_len &&
 		      os_memcmp(pmk, entry->pmk, pmk_len) == 0))) {
 			wpa_printf(MSG_DEBUG, "RSN: Flush PMKSA cache entry "
 				   "for " MACSTR, MAC2STR(entry->aa));
 			if (prev)
 				prev->next = entry->next;
 			else
 				pmksa->pmksa = entry->next;
 			tmp = entry;
 			entry = entry->next;
 			pmksa_cache_free_entry(pmksa, tmp, PMKSA_FREE);
 			removed++;
 		} else {
 			prev = entry;
 			entry = entry->next;
 		}
 	}
 	if (removed)
 		pmksa_cache_set_expiration(pmksa);
 }


 /**
  * pmksa_cache_deinit - Free all entries in PMKSA cache
  * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
  */
 void pmksa_cache_deinit(struct rsn_pmksa_cache *pmksa)
 {
 	struct rsn_pmksa_cache_entry *entry, *prev;

 	if (pmksa == NULL)
 		return;

 	entry = pmksa->pmksa;
 	pmksa->pmksa = NULL;
 	while (entry) {
 		prev = entry;
 		entry = entry->next;
 		os_free(prev);
 	}
 	pmksa_cache_set_expiration(pmksa);
 	os_free(pmksa);
 }


 /**
  * pmksa_cache_get - Fetch a PMKSA cache entry
  * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
  * @aa: Authenticator address or %NULL to match any
  * @pmkid: PMKID or %NULL to match any
  * @network_ctx: Network context or %NULL to match any
  * Returns: Pointer to PMKSA cache entry or %NULL if no match was found
  */
 struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa,
 					       const u8 *aa, const u8 *pmkid,
 					       const void *network_ctx)
 {
 	struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
 	while (entry) {
 		if ((aa == NULL || os_memcmp(entry->aa, aa, ETH_ALEN) == 0) &&
 		    (pmkid == NULL ||
 		     os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0) &&
 		    (network_ctx == NULL || network_ctx == entry->network_ctx))
 			return entry;
 		entry = entry->next;
 	}
 	return NULL;
 }


 static struct rsn_pmksa_cache_entry *
 pmksa_cache_clone_entry(struct rsn_pmksa_cache *pmksa,
 			const struct rsn_pmksa_cache_entry *old_entry,
 			const u8 *aa)
 {
 	struct rsn_pmksa_cache_entry *new_entry;

 	new_entry = pmksa_cache_add(pmksa, old_entry->pmk, old_entry->pmk_len,
 				    NULL, 0,
 				    aa, pmksa->sm->own_addr,
 				    old_entry->network_ctx, old_entry->akmp);
 	if (new_entry == NULL)
 		return NULL;

 	/* TODO: reorder entries based on expiration time? */
 	new_entry->expiration = old_entry->expiration;
 	new_entry->opportunistic = 1;

 	return new_entry;
 }


 /**
  * pmksa_cache_get_opportunistic - Try to get an opportunistic PMKSA entry
  * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
  * @network_ctx: Network configuration context
  * @aa: Authenticator address for the new AP
  * Returns: Pointer to a new PMKSA cache entry or %NULL if not available
  *
  * Try to create a new PMKSA cache entry opportunistically by guessing that the
  * new AP is sharing the same PMK as another AP that has the same SSID and has
  * already an entry in PMKSA cache.
  */
 struct rsn_pmksa_cache_entry *
 pmksa_cache_get_opportunistic(struct rsn_pmksa_cache *pmksa, void *network_ctx,
 			      const u8 *aa)
 {
 	struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;

 	wpa_printf(MSG_DEBUG, "RSN: Consider " MACSTR " for OKC", MAC2STR(aa));
 	if (network_ctx == NULL)
 		return NULL;
 	while (entry) {
 		if (entry->network_ctx == network_ctx) {
 			entry = pmksa_cache_clone_entry(pmksa, entry, aa);
 			if (entry) {
 				wpa_printf(MSG_DEBUG, "RSN: added "
 					   "opportunistic PMKSA cache entry "
 					   "for " MACSTR, MAC2STR(aa));
 			}
 			return entry;
 		}
 		entry = entry->next;
 	}
 	return NULL;
 }


 /**
  * pmksa_cache_get_current - Get the current used PMKSA entry
  * @sm: Pointer to WPA state machine data from wpa_sm_init()
  * Returns: Pointer to the current PMKSA cache entry or %NULL if not available
  */
 struct rsn_pmksa_cache_entry * pmksa_cache_get_current(struct wpa_sm *sm)
 {
 	if (sm == NULL)
 		return NULL;
 	return sm->cur_pmksa;
 }


 /**
  * pmksa_cache_clear_current - Clear the current PMKSA entry selection
  * @sm: Pointer to WPA state machine data from wpa_sm_init()
  */
 void pmksa_cache_clear_current(struct wpa_sm *sm)
 {
 	if (sm == NULL)
 		return;
 	sm->cur_pmksa = NULL;
 }


 /**
  * pmksa_cache_set_current - Set the current PMKSA entry selection
  * @sm: Pointer to WPA state machine data from wpa_sm_init()
  * @pmkid: PMKID for selecting PMKSA or %NULL if not used
  * @bssid: BSSID for PMKSA or %NULL if not used
  * @network_ctx: Network configuration context
  * @try_opportunistic: Whether to allow opportunistic PMKSA caching
  * Returns: 0 if PMKSA was found or -1 if no matching entry was found
  */
 int pmksa_cache_set_current(struct wpa_sm *sm, const u8 *pmkid,
 			    const u8 *bssid, void *network_ctx,
 			    int try_opportunistic)
 {
 	struct rsn_pmksa_cache *pmksa = sm->pmksa;
 	wpa_printf(MSG_DEBUG, "RSN: PMKSA cache search - network_ctx=%p "
 		   "try_opportunistic=%d", network_ctx, try_opportunistic);
 	if (pmkid)
 		wpa_hexdump(MSG_DEBUG, "RSN: Search for PMKID",
 			    pmkid, PMKID_LEN);
 	if (bssid)
 		wpa_printf(MSG_DEBUG, "RSN: Search for BSSID " MACSTR,
 			   MAC2STR(bssid));

 	sm->cur_pmksa = NULL;
 	if (pmkid)
 		sm->cur_pmksa = pmksa_cache_get(pmksa, NULL, pmkid,
 						network_ctx);
 	if (sm->cur_pmksa == NULL && bssid)
 		sm->cur_pmksa = pmksa_cache_get(pmksa, bssid, NULL,
 						network_ctx);
 	if (sm->cur_pmksa == NULL && try_opportunistic && bssid)
 		sm->cur_pmksa = pmksa_cache_get_opportunistic(pmksa,
 							      network_ctx,
 							      bssid);
 	if (sm->cur_pmksa) {
 		wpa_hexdump(MSG_DEBUG, "RSN: PMKSA cache entry found - PMKID",
 			    sm->cur_pmksa->pmkid, PMKID_LEN);
 		return 0;
 	}
 	wpa_printf(MSG_DEBUG, "RSN: No PMKSA cache entry found");
 	return -1;
 }


 /**
  * pmksa_cache_list - Dump text list of entries in PMKSA cache
  * @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
  * @buf: Buffer for the list
  * @len: Length of the buffer
  * Returns: number of bytes written to buffer
  *
  * This function is used to generate a text format representation of the
  * current PMKSA cache contents for the ctrl_iface PMKSA command.
  */
 int pmksa_cache_list(struct rsn_pmksa_cache *pmksa, char *buf, size_t len)
 {
 	int i, ret;
 	char *pos = buf;
 	struct rsn_pmksa_cache_entry *entry;
 	struct os_reltime now;

 	os_get_reltime(&now);
 	ret = os_snprintf(pos, buf + len - pos,
 			  "Index / AA / PMKID / expiration (in seconds) / "
 			  "opportunistic\n");
 	if (os_snprintf_error(buf + len - pos, ret))
 		return pos - buf;
 	pos += ret;
 	i = 0;
 	entry = pmksa->pmksa;
 	while (entry) {
 		i++;
 		ret = os_snprintf(pos, buf + len - pos, "%d " MACSTR " ",
 				  i, MAC2STR(entry->aa));
 		if (os_snprintf_error(buf + len - pos, ret))
 			return pos - buf;
 		pos += ret;
 		pos += wpa_snprintf_hex(pos, buf + len - pos, entry->pmkid,
 					PMKID_LEN);
 		ret = os_snprintf(pos, buf + len - pos, " %d %d\n",
 				  (int) (entry->expiration - now.sec),
 				  entry->opportunistic);
 		if (os_snprintf_error(buf + len - pos, ret))
 			return pos - buf;
 		pos += ret;
 		entry = entry->next;
 	}
 	return pos - buf;
 }


 /**
  * pmksa_cache_init - Initialize PMKSA cache
  * @free_cb: Callback function to be called when a PMKSA cache entry is freed
  * @ctx: Context pointer for free_cb function
  * @sm: Pointer to WPA state machine data from wpa_sm_init()
  * Returns: Pointer to PMKSA cache data or %NULL on failure
  */
 struct rsn_pmksa_cache *
 pmksa_cache_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry,
 				 void *ctx, enum pmksa_free_reason reason),
 		 void *ctx, struct wpa_sm *sm)
 {
 	struct rsn_pmksa_cache *pmksa;

 	pmksa = os_zalloc(sizeof(*pmksa));
 	if (pmksa) {
 		pmksa->free_cb = free_cb;
 		pmksa->ctx = ctx;
 		pmksa->sm = sm;
 	}

 	return pmksa;
 }

 #endif /* IEEE8021X_EAPOL */
	/*
	* WPA Supplicant - RSN PMKSA cache
	* Copyright (c) 2004-2009, 2011-2015, Jouni Malinen <j@w1.fi>
	*
	* This software may be distributed under the terms of the BSD license.
	* See README for more details.
	*/

	#include "includes.h"

	#include "common.h"
	#include "eloop.h"
	#include "eapol_supp/eapol_supp_sm.h"
	#include "wpa.h"
	#include "wpa_i.h"
	#include "pmksa_cache.h"

	#ifdef IEEE8021X_EAPOL

	static const int pmksa_cache_max_entries = 32;

	struct rsn_pmksa_cache {
	struct rsn_pmksa_cache_entry pmksa; / PMKSA cache */
	int pmksa_count; /* number of entries in PMKSA cache */
	struct wpa_sm sm; / TODO: get rid of this reference(?) */

	void (free_cb)(struct rsn_pmksa_cache_entry entry, void *ctx,
	enum pmksa_free_reason reason);
	void *ctx;
	};


	static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa);


	static void _pmksa_cache_free_entry(struct rsn_pmksa_cache_entry *entry)
	{
	bin_clear_free(entry, sizeof(*entry));
	}


	static void pmksa_cache_free_entry(struct rsn_pmksa_cache *pmksa,
	struct rsn_pmksa_cache_entry *entry,
	enum pmksa_free_reason reason)
	{
	wpa_sm_remove_pmkid(pmksa->sm, entry->aa, entry->pmkid);
	pmksa->pmksa_count--;
	pmksa->free_cb(entry, pmksa->ctx, reason);
	_pmksa_cache_free_entry(entry);
	}


	static void pmksa_cache_expire(void eloop_ctx, void timeout_ctx)
	{
	struct rsn_pmksa_cache *pmksa = eloop_ctx;
	struct os_reltime now;

	os_get_reltime(&now);
	while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) {
	struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
	pmksa->pmksa = entry->next;
	wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for "
	MACSTR, MAC2STR(entry->aa));
	pmksa_cache_free_entry(pmksa, entry, PMKSA_EXPIRE);
	}

	pmksa_cache_set_expiration(pmksa);
	}


	static void pmksa_cache_reauth(void eloop_ctx, void timeout_ctx)
	{
	struct rsn_pmksa_cache *pmksa = eloop_ctx;
	pmksa->sm->cur_pmksa = NULL;
	eapol_sm_request_reauth(pmksa->sm->eapol);
	}


	static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa)
	{
	int sec;
	struct rsn_pmksa_cache_entry *entry;
	struct os_reltime now;

	eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL);
	eloop_cancel_timeout(pmksa_cache_reauth, pmksa, NULL);
	if (pmksa->pmksa == NULL)
	return;
	os_get_reltime(&now);
	sec = pmksa->pmksa->expiration - now.sec;
	if (sec < 0)
	sec = 0;
	eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL);

	entry = pmksa->sm->cur_pmksa ? pmksa->sm->cur_pmksa :
	pmksa_cache_get(pmksa, pmksa->sm->bssid, NULL, NULL);
	if (entry) {
	sec = pmksa->pmksa->reauth_time - now.sec;
	if (sec < 0)
	sec = 0;
	eloop_register_timeout(sec, 0, pmksa_cache_reauth, pmksa,
	NULL);
	}
	}


	/**
	* pmksa_cache_add - Add a PMKSA cache entry
	* @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
	* @pmk: The new pairwise master key
	* @pmk_len: PMK length in bytes, usually PMK_LEN (32)
	* @kck: Key confirmation key or %NULL if not yet derived
	* @kck_len: KCK length in bytes
	* @aa: Authenticator address
	* @spa: Supplicant address
	* @network_ctx: Network configuration context for this PMK
	* @akmp: WPA_KEY_MGMT_* used in key derivation
	* Returns: Pointer to the added PMKSA cache entry or %NULL on error
	*
	* This function create a PMKSA entry for a new PMK and adds it to the PMKSA
	* cache. If an old entry is already in the cache for the same Authenticator,
	* this entry will be replaced with the new entry. PMKID will be calculated
	* based on the PMK and the driver interface is notified of the new PMKID.
	*/
	struct rsn_pmksa_cache_entry *
	pmksa_cache_add(struct rsn_pmksa_cache pmksa, const u8 pmk, size_t pmk_len,
	const u8 *kck, size_t kck_len,
	const u8 aa, const u8 spa, void *network_ctx, int akmp)
	{
	struct rsn_pmksa_cache_entry entry, pos, *prev;
	struct os_reltime now;

	if (pmk_len > PMK_LEN)
	return NULL;

	if (wpa_key_mgmt_suite_b(akmp) && !kck)
	return NULL;

	entry = os_zalloc(sizeof(*entry));
	if (entry == NULL)
	return NULL;
	os_memcpy(entry->pmk, pmk, pmk_len);
	entry->pmk_len = pmk_len;
	if (akmp == WPA_KEY_MGMT_IEEE8021X_SUITE_B_192)
	rsn_pmkid_suite_b_192(kck, kck_len, aa, spa, entry->pmkid);
	else if (wpa_key_mgmt_suite_b(akmp))
	rsn_pmkid_suite_b(kck, kck_len, aa, spa, entry->pmkid);
	else
	rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid,
	wpa_key_mgmt_sha256(akmp));
	os_get_reltime(&now);
	entry->expiration = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime;
	entry->reauth_time = now.sec + pmksa->sm->dot11RSNAConfigPMKLifetime *
	pmksa->sm->dot11RSNAConfigPMKReauthThreshold / 100;
	entry->akmp = akmp;
	os_memcpy(entry->aa, aa, ETH_ALEN);
	entry->network_ctx = network_ctx;

	/* Replace an old entry for the same Authenticator (if found) with the
	* new entry */
	pos = pmksa->pmksa;
	prev = NULL;
	while (pos) {
	if (os_memcmp(aa, pos->aa, ETH_ALEN) == 0) {
	if (pos->pmk_len == pmk_len &&
	os_memcmp_const(pos->pmk, pmk, pmk_len) == 0 &&
	os_memcmp_const(pos->pmkid, entry->pmkid,
	PMKID_LEN) == 0) {
	wpa_printf(MSG_DEBUG, "WPA: reusing previous "
	"PMKSA entry");
	os_free(entry);
	return pos;
	}
	if (prev == NULL)
	pmksa->pmksa = pos->next;
	else
	prev->next = pos->next;

	/*
	* If OKC is used, there may be other PMKSA cache
	* entries based on the same PMK. These needs to be
	* flushed so that a new entry can be created based on
	* the new PMK. Only clear other entries if they have a
	* matching PMK and this PMK has been used successfully
	* with the current AP, i.e., if opportunistic flag has
	* been cleared in wpa_supplicant_key_neg_complete().
	*/
	wpa_printf(MSG_DEBUG, "RSN: Replace PMKSA entry for "
	"the current AP and any PMKSA cache entry "
	"that was based on the old PMK");
	if (!pos->opportunistic)
	pmksa_cache_flush(pmksa, network_ctx, pos->pmk,
	pos->pmk_len);
	pmksa_cache_free_entry(pmksa, pos, PMKSA_REPLACE);
	break;
	}
	prev = pos;
	pos = pos->next;
	}

	if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) {
	/* Remove the oldest entry to make room for the new entry */
	pos = pmksa->pmksa;

	if (pos == pmksa->sm->cur_pmksa) {
	/*
	* Never remove the current PMKSA cache entry, since
	* it's in use, and removing it triggers a needless
	* deauthentication.
	*/
	pos = pos->next;
	pmksa->pmksa->next = pos ? pos->next : NULL;
	} else
	pmksa->pmksa = pos->next;

	if (pos) {
	wpa_printf(MSG_DEBUG, "RSN: removed the oldest idle "
	"PMKSA cache entry (for " MACSTR ") to "
	"make room for new one",
	MAC2STR(pos->aa));
	pmksa_cache_free_entry(pmksa, pos, PMKSA_FREE);
	}
	}

	/* 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;
	pmksa_cache_set_expiration(pmksa);
	} else {
	entry->next = prev->next;
	prev->next = entry;
	}
	pmksa->pmksa_count++;
	wpa_printf(MSG_DEBUG, "RSN: Added PMKSA cache entry for " MACSTR
	" network_ctx=%p", MAC2STR(entry->aa), network_ctx);
	wpa_sm_add_pmkid(pmksa->sm, entry->aa, entry->pmkid);

	return entry;
	}


	/**
	* pmksa_cache_flush - Flush PMKSA cache entries for a specific network
	* @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
	* @network_ctx: Network configuration context or %NULL to flush all entries
	* @pmk: PMK to match for or %NYLL to match all PMKs
	* @pmk_len: PMK length
	*/
	void pmksa_cache_flush(struct rsn_pmksa_cache pmksa, void network_ctx,
	const u8 *pmk, size_t pmk_len)
	{
	struct rsn_pmksa_cache_entry entry, prev = NULL, *tmp;
	int removed = 0;

	entry = pmksa->pmksa;
	while (entry) {
	if ((entry->network_ctx == network_ctx \|\|
	network_ctx == NULL) &&
	(pmk == NULL \|\|
	(pmk_len == entry->pmk_len &&
	os_memcmp(pmk, entry->pmk, pmk_len) == 0))) {
	wpa_printf(MSG_DEBUG, "RSN: Flush PMKSA cache entry "
	"for " MACSTR, MAC2STR(entry->aa));
	if (prev)
	prev->next = entry->next;
	else
	pmksa->pmksa = entry->next;
	tmp = entry;
	entry = entry->next;
	pmksa_cache_free_entry(pmksa, tmp, PMKSA_FREE);
	removed++;
	} else {
	prev = entry;
	entry = entry->next;
	}
	}
	if (removed)
	pmksa_cache_set_expiration(pmksa);
	}


	/**
	* pmksa_cache_deinit - Free all entries in PMKSA cache
	* @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
	*/
	void pmksa_cache_deinit(struct rsn_pmksa_cache *pmksa)
	{
	struct rsn_pmksa_cache_entry entry, prev;

	if (pmksa == NULL)
	return;

	entry = pmksa->pmksa;
	pmksa->pmksa = NULL;
	while (entry) {
	prev = entry;
	entry = entry->next;
	os_free(prev);
	}
	pmksa_cache_set_expiration(pmksa);
	os_free(pmksa);
	}


	/**
	* pmksa_cache_get - Fetch a PMKSA cache entry
	* @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
	* @aa: Authenticator address or %NULL to match any
	* @pmkid: PMKID or %NULL to match any
	* @network_ctx: Network context or %NULL to match any
	* Returns: Pointer to PMKSA cache entry or %NULL if no match was found
	*/
	struct rsn_pmksa_cache_entry * pmksa_cache_get(struct rsn_pmksa_cache *pmksa,
	const u8 aa, const u8 pmkid,
	const void *network_ctx)
	{
	struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
	while (entry) {
	if ((aa == NULL \|\| os_memcmp(entry->aa, aa, ETH_ALEN) == 0) &&
	(pmkid == NULL \|\|
	os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0) &&
	(network_ctx == NULL \|\| network_ctx == entry->network_ctx))
	return entry;
	entry = entry->next;
	}
	return NULL;
	}


	static struct rsn_pmksa_cache_entry *
	pmksa_cache_clone_entry(struct rsn_pmksa_cache *pmksa,
	const struct rsn_pmksa_cache_entry *old_entry,
	const u8 *aa)
	{
	struct rsn_pmksa_cache_entry *new_entry;

	new_entry = pmksa_cache_add(pmksa, old_entry->pmk, old_entry->pmk_len,
	NULL, 0,
	aa, pmksa->sm->own_addr,
	old_entry->network_ctx, old_entry->akmp);
	if (new_entry == NULL)
	return NULL;

	/* TODO: reorder entries based on expiration time? */
	new_entry->expiration = old_entry->expiration;
	new_entry->opportunistic = 1;

	return new_entry;
	}


	/**
	* pmksa_cache_get_opportunistic - Try to get an opportunistic PMKSA entry
	* @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
	* @network_ctx: Network configuration context
	* @aa: Authenticator address for the new AP
	* Returns: Pointer to a new PMKSA cache entry or %NULL if not available
	*
	* Try to create a new PMKSA cache entry opportunistically by guessing that the
	* new AP is sharing the same PMK as another AP that has the same SSID and has
	* already an entry in PMKSA cache.
	*/
	struct rsn_pmksa_cache_entry *
	pmksa_cache_get_opportunistic(struct rsn_pmksa_cache pmksa, void network_ctx,
	const u8 *aa)
	{
	struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;

	wpa_printf(MSG_DEBUG, "RSN: Consider " MACSTR " for OKC", MAC2STR(aa));
	if (network_ctx == NULL)
	return NULL;
	while (entry) {
	if (entry->network_ctx == network_ctx) {
	entry = pmksa_cache_clone_entry(pmksa, entry, aa);
	if (entry) {
	wpa_printf(MSG_DEBUG, "RSN: added "
	"opportunistic PMKSA cache entry "
	"for " MACSTR, MAC2STR(aa));
	}
	return entry;
	}
	entry = entry->next;
	}
	return NULL;
	}


	/**
	* pmksa_cache_get_current - Get the current used PMKSA entry
	* @sm: Pointer to WPA state machine data from wpa_sm_init()
	* Returns: Pointer to the current PMKSA cache entry or %NULL if not available
	*/
	struct rsn_pmksa_cache_entry * pmksa_cache_get_current(struct wpa_sm *sm)
	{
	if (sm == NULL)
	return NULL;
	return sm->cur_pmksa;
	}


	/**
	* pmksa_cache_clear_current - Clear the current PMKSA entry selection
	* @sm: Pointer to WPA state machine data from wpa_sm_init()
	*/
	void pmksa_cache_clear_current(struct wpa_sm *sm)
	{
	if (sm == NULL)
	return;
	sm->cur_pmksa = NULL;
	}


	/**
	* pmksa_cache_set_current - Set the current PMKSA entry selection
	* @sm: Pointer to WPA state machine data from wpa_sm_init()
	* @pmkid: PMKID for selecting PMKSA or %NULL if not used
	* @bssid: BSSID for PMKSA or %NULL if not used
	* @network_ctx: Network configuration context
	* @try_opportunistic: Whether to allow opportunistic PMKSA caching
	* Returns: 0 if PMKSA was found or -1 if no matching entry was found
	*/
	int pmksa_cache_set_current(struct wpa_sm sm, const u8 pmkid,
	const u8 bssid, void network_ctx,
	int try_opportunistic)
	{
	struct rsn_pmksa_cache *pmksa = sm->pmksa;
	wpa_printf(MSG_DEBUG, "RSN: PMKSA cache search - network_ctx=%p "
	"try_opportunistic=%d", network_ctx, try_opportunistic);
	if (pmkid)
	wpa_hexdump(MSG_DEBUG, "RSN: Search for PMKID",
	pmkid, PMKID_LEN);
	if (bssid)
	wpa_printf(MSG_DEBUG, "RSN: Search for BSSID " MACSTR,
	MAC2STR(bssid));

	sm->cur_pmksa = NULL;
	if (pmkid)
	sm->cur_pmksa = pmksa_cache_get(pmksa, NULL, pmkid,
	network_ctx);
	if (sm->cur_pmksa == NULL && bssid)
	sm->cur_pmksa = pmksa_cache_get(pmksa, bssid, NULL,
	network_ctx);
	if (sm->cur_pmksa == NULL && try_opportunistic && bssid)
	sm->cur_pmksa = pmksa_cache_get_opportunistic(pmksa,
	network_ctx,
	bssid);
	if (sm->cur_pmksa) {
	wpa_hexdump(MSG_DEBUG, "RSN: PMKSA cache entry found - PMKID",
	sm->cur_pmksa->pmkid, PMKID_LEN);
	return 0;
	}
	wpa_printf(MSG_DEBUG, "RSN: No PMKSA cache entry found");
	return -1;
	}


	/**
	* pmksa_cache_list - Dump text list of entries in PMKSA cache
	* @pmksa: Pointer to PMKSA cache data from pmksa_cache_init()
	* @buf: Buffer for the list
	* @len: Length of the buffer
	* Returns: number of bytes written to buffer
	*
	* This function is used to generate a text format representation of the
	* current PMKSA cache contents for the ctrl_iface PMKSA command.
	*/
	int pmksa_cache_list(struct rsn_pmksa_cache pmksa, char buf, size_t len)
	{
	int i, ret;
	char *pos = buf;
	struct rsn_pmksa_cache_entry *entry;
	struct os_reltime now;

	os_get_reltime(&now);
	ret = os_snprintf(pos, buf + len - pos,
	"Index / AA / PMKID / expiration (in seconds) / "
	"opportunistic\n");
	if (os_snprintf_error(buf + len - pos, ret))
	return pos - buf;
	pos += ret;
	i = 0;
	entry = pmksa->pmksa;
	while (entry) {
	i++;
	ret = os_snprintf(pos, buf + len - pos, "%d " MACSTR " ",
	i, MAC2STR(entry->aa));
	if (os_snprintf_error(buf + len - pos, ret))
	return pos - buf;
	pos += ret;
	pos += wpa_snprintf_hex(pos, buf + len - pos, entry->pmkid,
	PMKID_LEN);
	ret = os_snprintf(pos, buf + len - pos, " %d %d\n",
	(int) (entry->expiration - now.sec),
	entry->opportunistic);
	if (os_snprintf_error(buf + len - pos, ret))
	return pos - buf;
	pos += ret;
	entry = entry->next;
	}
	return pos - buf;
	}


	/**
	* pmksa_cache_init - Initialize PMKSA cache
	* @free_cb: Callback function to be called when a PMKSA cache entry is freed
	* @ctx: Context pointer for free_cb function
	* @sm: Pointer to WPA state machine data from wpa_sm_init()
	* Returns: Pointer to PMKSA cache data or %NULL on failure
	*/
	struct rsn_pmksa_cache *
	pmksa_cache_init(void (free_cb)(struct rsn_pmksa_cache_entry entry,
	void *ctx, enum pmksa_free_reason reason),
	void ctx, struct wpa_sm sm)
	{
	struct rsn_pmksa_cache *pmksa;

	pmksa = os_zalloc(sizeof(*pmksa));
	if (pmksa) {
	pmksa->free_cb = free_cb;
	pmksa->ctx = ctx;
	pmksa->sm = sm;
	}

	return pmksa;
	}

	#endif /* IEEE8021X_EAPOL */