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Commit 5622f5bb authored by Johannes Berg's avatar Johannes Berg
Browse files

cfg80211: refactor hidden SSID finding 



Instead of duplicating the rbtree functions, pass
an argument to the compare function. This removes
the code duplication for the two searches.

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 42745e03

net/wireless/scan.c

+20 −62
Original line number Diff line number Diff line
@@ -425,34 +425,13 @@ static int cmp_bss_core(struct cfg80211_bss *a, struct cfg80211_bss *b) 
}



static int cmp_bss(struct cfg80211_bss *a,

		   struct cfg80211_bss *b)

{

	const struct cfg80211_bss_ies *a_ies, *b_ies;

	int r;



	r = cmp_bss_core(a, b);

	if (r)

		return r;



	a_ies = rcu_access_pointer(a->ies);

	if (!a_ies)

		return -1;

	b_ies = rcu_access_pointer(b->ies);

	if (!b_ies)

		return 1;



	return cmp_ies(WLAN_EID_SSID,

		       a_ies->data, a_ies->len,

		       b_ies->data, b_ies->len);

}



static int cmp_hidden_bss(struct cfg80211_bss *a, struct cfg80211_bss *b)

		   struct cfg80211_bss *b,

		   bool hide_ssid)

{

	const struct cfg80211_bss_ies *a_ies, *b_ies;

	const u8 *ie1;

	const u8 *ie2;

	int i;

	int r;

	int i, r;



	r = cmp_bss_core(a, b);

	if (r)
@@ -468,15 +447,13 @@ static int cmp_hidden_bss(struct cfg80211_bss *a, struct cfg80211_bss *b) 
	ie1 = cfg80211_find_ie(WLAN_EID_SSID, a_ies->data, a_ies->len);

	ie2 = cfg80211_find_ie(WLAN_EID_SSID, b_ies->data, b_ies->len);



	if (!ie1 && !ie2)

		return 0;



	/*

	 * Key comparator must use same algorithm in any rb-tree

	 * search function (order is important), otherwise ordering

	 * of items in the tree is broken and search gives incorrect

	 * results. This code uses same order as cmp_ies() does.

	 *

	 * Note that due to the differring behaviour with hidden SSIDs

	 * this function only works when "b" is the tree element and

	 * "a" is the key we're looking for.

	 * Note that with "hide_ssid", the function returns a match if

	 * the already-present BSS ("b") is a hidden SSID beacon for

	 * the new BSS ("a").

	 */



	/* sort missing IE before (left of) present IE */
@@ -485,14 +462,17 @@ static int cmp_hidden_bss(struct cfg80211_bss *a, struct cfg80211_bss *b) 
	if (!ie2)

		return 1;



	/* zero-size SSID is used as an indication of the hidden bss */

	if (!ie2[1])

	/* zero-length SSID is used as an indication of the hidden bss */

	if (hide_ssid && !ie2[1])

		return 0;



	/* sort by length first, then by contents */

	if (ie1[1] != ie2[1])

		return ie2[1] - ie1[1];



	if (!hide_ssid)

		return memcmp(ie1 + 2, ie2 + 2, ie1[1]);



	/*

	 * zeroed SSID ie is another indication of a hidden bss;

	 * if it isn't zeroed just return the regular sort value
@@ -584,7 +564,7 @@ static void rb_insert_bss(struct cfg80211_registered_device *dev, 
		parent = *p;

		tbss = rb_entry(parent, struct cfg80211_internal_bss, rbn);



		cmp = cmp_bss(&bss->pub, &tbss->pub);

		cmp = cmp_bss(&bss->pub, &tbss->pub, false);



		if (WARN_ON(!cmp)) {

			/* will sort of leak this BSS */
@@ -603,30 +583,8 @@ static void rb_insert_bss(struct cfg80211_registered_device *dev, 


static struct cfg80211_internal_bss *

rb_find_bss(struct cfg80211_registered_device *dev,

	    struct cfg80211_internal_bss *res)

{

	struct rb_node *n = dev->bss_tree.rb_node;

	struct cfg80211_internal_bss *bss;

	int r;



	while (n) {

		bss = rb_entry(n, struct cfg80211_internal_bss, rbn);

		r = cmp_bss(&res->pub, &bss->pub);



		if (r == 0)

			return bss;

		else if (r < 0)

			n = n->rb_left;

		else

			n = n->rb_right;

	}



	return NULL;

}



static struct cfg80211_internal_bss *

rb_find_hidden_bss(struct cfg80211_registered_device *dev,

		   struct cfg80211_internal_bss *res)

	    struct cfg80211_internal_bss *res,

	    bool hidden)

{

	struct rb_node *n = dev->bss_tree.rb_node;

	struct cfg80211_internal_bss *bss;
@@ -634,7 +592,7 @@ rb_find_hidden_bss(struct cfg80211_registered_device *dev, 


	while (n) {

		bss = rb_entry(n, struct cfg80211_internal_bss, rbn);

		r = cmp_hidden_bss(&res->pub, &bss->pub);

		r = cmp_bss(&res->pub, &bss->pub, hidden);



		if (r == 0)

			return bss;
@@ -684,7 +642,7 @@ cfg80211_bss_update(struct cfg80211_registered_device *dev, 
		return NULL;

	}



	found = rb_find_bss(dev, tmp);

	found = rb_find_bss(dev, tmp, false);



	if (found) {

		found->pub.beacon_interval = tmp->pub.beacon_interval;
@@ -739,7 +697,7 @@ cfg80211_bss_update(struct cfg80211_registered_device *dev, 
		/* TODO: The code is not trying to update existing probe

		 * response bss entries when beacon ies are

		 * getting changed. */

		hidden = rb_find_hidden_bss(dev, tmp);

		hidden = rb_find_bss(dev, tmp, true);

		if (hidden)

			copy_hidden_ies(tmp, hidden);