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cfg80211: refactor hidden SSID finding

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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>
This commit is contained in:
Johannes Berg 2013-01-30 00:26:45 +01:00
parent 42745e0393
commit 5622f5bb8d
1 changed files with 20 additions and 62 deletions
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82
net/wireless/scan.c
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@ -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, static int cmp_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;
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)
{ {
const struct cfg80211_bss_ies *a_ies, *b_ies; const struct cfg80211_bss_ies *a_ies, *b_ies;
const u8 *ie1; const u8 *ie1;
const u8 *ie2; const u8 *ie2;
int i; int i, r;
int r;
r = cmp_bss_core(a, b); r = cmp_bss_core(a, b);
if (r) 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); 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); 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 * Note that with "hide_ssid", the function returns a match if
* search function (order is important), otherwise ordering * the already-present BSS ("b") is a hidden SSID beacon for
* of items in the tree is broken and search gives incorrect * the new BSS ("a").
* 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.
*/ */
/* sort missing IE before (left of) present IE */ /* 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) if (!ie2)
return 1; return 1;
/* zero-size SSID is used as an indication of the hidden bss */ /* zero-length SSID is used as an indication of the hidden bss */
if (!ie2[1]) if (hide_ssid && !ie2[1])
return 0; return 0;
/* sort by length first, then by contents */ /* sort by length first, then by contents */
if (ie1[1] != ie2[1]) if (ie1[1] != ie2[1])
return ie2[1] - ie1[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; * zeroed SSID ie is another indication of a hidden bss;
* if it isn't zeroed just return the regular sort value * 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; parent = *p;
tbss = rb_entry(parent, struct cfg80211_internal_bss, rbn); 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)) { if (WARN_ON(!cmp)) {
/* will sort of leak this BSS */ /* will sort of leak this BSS */
@ -603,7 +583,8 @@ static void rb_insert_bss(struct cfg80211_registered_device *dev,
static struct cfg80211_internal_bss * static struct cfg80211_internal_bss *
rb_find_bss(struct cfg80211_registered_device *dev, rb_find_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 rb_node *n = dev->bss_tree.rb_node;
struct cfg80211_internal_bss *bss; struct cfg80211_internal_bss *bss;
@ -611,30 +592,7 @@ rb_find_bss(struct cfg80211_registered_device *dev,
while (n) { while (n) {
bss = rb_entry(n, struct cfg80211_internal_bss, rbn); bss = rb_entry(n, struct cfg80211_internal_bss, rbn);
r = cmp_bss(&res->pub, &bss->pub); r = cmp_bss(&res->pub, &bss->pub, hidden);
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 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_hidden_bss(&res->pub, &bss->pub);
if (r == 0) if (r == 0)
return bss; return bss;
@ -684,7 +642,7 @@ cfg80211_bss_update(struct cfg80211_registered_device *dev,
return NULL; return NULL;
} }
found = rb_find_bss(dev, tmp); found = rb_find_bss(dev, tmp, false);
if (found) { if (found) {
found->pub.beacon_interval = tmp->pub.beacon_interval; 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 /* TODO: The code is not trying to update existing probe
* response bss entries when beacon ies are * response bss entries when beacon ies are
* getting changed. */ * getting changed. */
hidden = rb_find_hidden_bss(dev, tmp); hidden = rb_find_bss(dev, tmp, true);
if (hidden) if (hidden)
copy_hidden_ies(tmp, hidden); copy_hidden_ies(tmp, hidden);