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: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index ca367c58a3e2ad06a156d0922a4b53ba92f57dff..cfc4e1aa8dad706be6a6fad031b5082a9c054e4c 100644 (file)
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -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);