diff options
| -rw-r--r-- | net/wireless/scan.c | 117 |
1 files changed, 114 insertions, 3 deletions
diff --git a/net/wireless/scan.c b/net/wireless/scan.c index dc23b31594e0..31119e32e092 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -355,8 +355,8 @@ static bool is_mesh(struct cfg80211_bss *a, sizeof(struct ieee80211_meshconf_ie) - 2) == 0; } -static int cmp_bss(struct cfg80211_bss *a, - struct cfg80211_bss *b) +static int cmp_bss_core(struct cfg80211_bss *a, + struct cfg80211_bss *b) { int r; @@ -378,7 +378,15 @@ static int cmp_bss(struct cfg80211_bss *a, b->len_information_elements); } - r = memcmp(a->bssid, b->bssid, ETH_ALEN); + return memcmp(a->bssid, b->bssid, ETH_ALEN); +} + +static int cmp_bss(struct cfg80211_bss *a, + struct cfg80211_bss *b) +{ + int r; + + r = cmp_bss_core(a, b); if (r) return r; @@ -389,6 +397,52 @@ static int cmp_bss(struct cfg80211_bss *a, b->len_information_elements); } +static int cmp_hidden_bss(struct cfg80211_bss *a, + struct cfg80211_bss *b) +{ + const u8 *ie1; + const u8 *ie2; + int i; + int r; + + r = cmp_bss_core(a, b); + if (r) + return r; + + ie1 = cfg80211_find_ie(WLAN_EID_SSID, + a->information_elements, + a->len_information_elements); + ie2 = cfg80211_find_ie(WLAN_EID_SSID, + b->information_elements, + b->len_information_elements); + + /* 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. */ + + /* sort missing IE before (left of) present IE */ + if (!ie1) + return -1; + if (!ie2) + return 1; + + /* zero-size SSID is used as an indication of the hidden bss */ + if (!ie2[1]) + return 0; + + /* sort by length first, then by contents */ + if (ie1[1] != ie2[1]) + return ie2[1] - ie1[1]; + + /* zeroed SSID ie is another indication of a hidden bss */ + for (i = 0; i < ie2[1]; i++) + if (ie2[i + 2]) + return -1; + + return 0; +} + struct cfg80211_bss *cfg80211_get_bss(struct wiphy *wiphy, struct ieee80211_channel *channel, const u8 *bssid, @@ -505,6 +559,48 @@ rb_find_bss(struct cfg80211_registered_device *dev, } 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) + return bss; + else if (r < 0) + n = n->rb_left; + else + n = n->rb_right; + } + + return NULL; +} + +static void +copy_hidden_ies(struct cfg80211_internal_bss *res, + struct cfg80211_internal_bss *hidden) +{ + if (unlikely(res->pub.beacon_ies)) + return; + if (WARN_ON(!hidden->pub.beacon_ies)) + return; + + res->pub.beacon_ies = kmalloc(hidden->pub.len_beacon_ies, GFP_ATOMIC); + if (unlikely(!res->pub.beacon_ies)) + return; + + res->beacon_ies_allocated = true; + res->pub.len_beacon_ies = hidden->pub.len_beacon_ies; + memcpy(res->pub.beacon_ies, hidden->pub.beacon_ies, + res->pub.len_beacon_ies); +} + +static struct cfg80211_internal_bss * cfg80211_bss_update(struct cfg80211_registered_device *dev, struct cfg80211_internal_bss *res) { @@ -607,6 +703,21 @@ cfg80211_bss_update(struct cfg80211_registered_device *dev, kref_put(&res->ref, bss_release); } else { + struct cfg80211_internal_bss *hidden; + + /* First check if the beacon is a probe response from + * a hidden bss. If so, copy beacon ies (with nullified + * ssid) into the probe response bss entry (with real ssid). + * It is required basically for PSM implementation + * (probe responses do not contain tim ie) */ + + /* 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, res); + if (hidden) + copy_hidden_ies(res, hidden); + /* this "consumes" the reference */ list_add_tail(&res->list, &dev->bss_list); rb_insert_bss(dev, res); |