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scan.c
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/*
* cfg80211 scan result handling
*
* Copyright 2008 Johannes Berg <[email protected]>
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/wireless.h>
#include <linux/nl80211.h>
#include <linux/etherdevice.h>
#include <net/arp.h>
#include <net/cfg80211.h>
#include <net/cfg80211-wext.h>
#include <net/iw_handler.h>
#include "core.h"
#include "nl80211.h"
#include "wext-compat.h"
#include "rdev-ops.h"
/**
* DOC: BSS tree/list structure
*
* At the top level, the BSS list is kept in both a list in each
* registered device (@bss_list) as well as an RB-tree for faster
* lookup. In the RB-tree, entries can be looked up using their
* channel, MESHID, MESHCONF (for MBSSes) or channel, BSSID, SSID
* for other BSSes.
*
* Due to the possibility of hidden SSIDs, there's a second level
* structure, the "hidden_list" and "hidden_beacon_bss" pointer.
* The hidden_list connects all BSSes belonging to a single AP
* that has a hidden SSID, and connects beacon and probe response
* entries. For a probe response entry for a hidden SSID, the
* hidden_beacon_bss pointer points to the BSS struct holding the
* beacon's information.
*
* Reference counting is done for all these references except for
* the hidden_list, so that a beacon BSS struct that is otherwise
* not referenced has one reference for being on the bss_list and
* one for each probe response entry that points to it using the
* hidden_beacon_bss pointer. When a BSS struct that has such a
* pointer is get/put, the refcount update is also propagated to
* the referenced struct, this ensure that it cannot get removed
* while somebody is using the probe response version.
*
* Note that the hidden_beacon_bss pointer never changes, due to
* the reference counting. Therefore, no locking is needed for
* it.
*
* Also note that the hidden_beacon_bss pointer is only relevant
* if the driver uses something other than the IEs, e.g. private
* data stored stored in the BSS struct, since the beacon IEs are
* also linked into the probe response struct.
*/
#define IEEE80211_SCAN_RESULT_EXPIRE (30 * HZ)
static void bss_free(struct cfg80211_internal_bss *bss)
{
struct cfg80211_bss_ies *ies;
if (WARN_ON(atomic_read(&bss->hold)))
return;
ies = (void *)rcu_access_pointer(bss->pub.beacon_ies);
if (ies && !bss->pub.hidden_beacon_bss)
kfree_rcu(ies, rcu_head);
ies = (void *)rcu_access_pointer(bss->pub.proberesp_ies);
if (ies)
kfree_rcu(ies, rcu_head);
/*
* This happens when the module is removed, it doesn't
* really matter any more save for completeness
*/
if (!list_empty(&bss->hidden_list))
list_del(&bss->hidden_list);
kfree(bss);
}
static inline void bss_ref_get(struct cfg80211_registered_device *dev,
struct cfg80211_internal_bss *bss)
{
lockdep_assert_held(&dev->bss_lock);
bss->refcount++;
if (bss->pub.hidden_beacon_bss) {
bss = container_of(bss->pub.hidden_beacon_bss,
struct cfg80211_internal_bss,
pub);
bss->refcount++;
}
}
static inline void bss_ref_put(struct cfg80211_registered_device *dev,
struct cfg80211_internal_bss *bss)
{
lockdep_assert_held(&dev->bss_lock);
if (bss->pub.hidden_beacon_bss) {
struct cfg80211_internal_bss *hbss;
hbss = container_of(bss->pub.hidden_beacon_bss,
struct cfg80211_internal_bss,
pub);
hbss->refcount--;
if (hbss->refcount == 0)
bss_free(hbss);
}
bss->refcount--;
if (bss->refcount == 0)
bss_free(bss);
}
static bool __cfg80211_unlink_bss(struct cfg80211_registered_device *dev,
struct cfg80211_internal_bss *bss)
{
lockdep_assert_held(&dev->bss_lock);
if (!list_empty(&bss->hidden_list)) {
/*
* don't remove the beacon entry if it has
* probe responses associated with it
*/
if (!bss->pub.hidden_beacon_bss)
return false;
/*
* if it's a probe response entry break its
* link to the other entries in the group
*/
list_del_init(&bss->hidden_list);
}
list_del_init(&bss->list);
rb_erase(&bss->rbn, &dev->bss_tree);
bss_ref_put(dev, bss);
return true;
}
static void __cfg80211_bss_expire(struct cfg80211_registered_device *dev,
unsigned long expire_time)
{
struct cfg80211_internal_bss *bss, *tmp;
bool expired = false;
lockdep_assert_held(&dev->bss_lock);
list_for_each_entry_safe(bss, tmp, &dev->bss_list, list) {
if (atomic_read(&bss->hold))
continue;
if (!time_after(expire_time, bss->ts))
continue;
if (__cfg80211_unlink_bss(dev, bss))
expired = true;
}
if (expired)
dev->bss_generation++;
}
void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev, bool leak)
{
struct cfg80211_scan_request *request;
struct wireless_dev *wdev;
#ifdef CONFIG_CFG80211_WEXT
union iwreq_data wrqu;
#endif
ASSERT_RTNL();
request = rdev->scan_req;
if (!request)
return;
wdev = request->wdev;
/*
* This must be before sending the other events!
* Otherwise, wpa_supplicant gets completely confused with
* wext events.
*/
if (wdev->netdev)
cfg80211_sme_scan_done(wdev->netdev);
if (request->aborted) {
nl80211_send_scan_aborted(rdev, wdev);
} else {
if (request->flags & NL80211_SCAN_FLAG_FLUSH) {
/* flush entries from previous scans */
spin_lock_bh(&rdev->bss_lock);
__cfg80211_bss_expire(rdev, request->scan_start);
spin_unlock_bh(&rdev->bss_lock);
}
nl80211_send_scan_done(rdev, wdev);
}
#ifdef CONFIG_CFG80211_WEXT
if (wdev->netdev && !request->aborted) {
memset(&wrqu, 0, sizeof(wrqu));
wireless_send_event(wdev->netdev, SIOCGIWSCAN, &wrqu, NULL);
}
#endif
if (wdev->netdev)
dev_put(wdev->netdev);
rdev->scan_req = NULL;
/*
* OK. If this is invoked with "leak" then we can't
* free this ... but we've cleaned it up anyway. The
* driver failed to call the scan_done callback, so
* all bets are off, it might still be trying to use
* the scan request or not ... if it accesses the dev
* in there (it shouldn't anyway) then it may crash.
*/
if (!leak)
kfree(request);
}
void __cfg80211_scan_done(struct work_struct *wk)
{
struct cfg80211_registered_device *rdev;
rdev = container_of(wk, struct cfg80211_registered_device,
scan_done_wk);
rtnl_lock();
___cfg80211_scan_done(rdev, false);
rtnl_unlock();
}
void cfg80211_scan_done(struct cfg80211_scan_request *request, bool aborted)
{
trace_cfg80211_scan_done(request, aborted);
WARN_ON(request != wiphy_to_dev(request->wiphy)->scan_req);
request->aborted = aborted;
request->notified = true;
queue_work(cfg80211_wq, &wiphy_to_dev(request->wiphy)->scan_done_wk);
}
EXPORT_SYMBOL(cfg80211_scan_done);
void __cfg80211_sched_scan_results(struct work_struct *wk)
{
struct cfg80211_registered_device *rdev;
struct cfg80211_sched_scan_request *request;
rdev = container_of(wk, struct cfg80211_registered_device,
sched_scan_results_wk);
request = rdev->sched_scan_req;
rtnl_lock();
/* we don't have sched_scan_req anymore if the scan is stopping */
if (request) {
if (request->flags & NL80211_SCAN_FLAG_FLUSH) {
/* flush entries from previous scans */
spin_lock_bh(&rdev->bss_lock);
__cfg80211_bss_expire(rdev, request->scan_start);
spin_unlock_bh(&rdev->bss_lock);
request->scan_start =
jiffies + msecs_to_jiffies(request->interval);
}
nl80211_send_sched_scan_results(rdev, request->dev);
}
rtnl_unlock();
}
void cfg80211_sched_scan_results(struct wiphy *wiphy)
{
trace_cfg80211_sched_scan_results(wiphy);
/* ignore if we're not scanning */
if (wiphy_to_dev(wiphy)->sched_scan_req)
queue_work(cfg80211_wq,
&wiphy_to_dev(wiphy)->sched_scan_results_wk);
}
EXPORT_SYMBOL(cfg80211_sched_scan_results);
void cfg80211_sched_scan_stopped(struct wiphy *wiphy)
{
struct cfg80211_registered_device *rdev = wiphy_to_dev(wiphy);
trace_cfg80211_sched_scan_stopped(wiphy);
rtnl_lock();
__cfg80211_stop_sched_scan(rdev, true);
rtnl_unlock();
}
EXPORT_SYMBOL(cfg80211_sched_scan_stopped);
int __cfg80211_stop_sched_scan(struct cfg80211_registered_device *rdev,
bool driver_initiated)
{
struct net_device *dev;
ASSERT_RTNL();
if (!rdev->sched_scan_req)
return -ENOENT;
dev = rdev->sched_scan_req->dev;
if (!driver_initiated) {
int err = rdev_sched_scan_stop(rdev, dev);
if (err)
return err;
}
nl80211_send_sched_scan(rdev, dev, NL80211_CMD_SCHED_SCAN_STOPPED);
kfree(rdev->sched_scan_req);
rdev->sched_scan_req = NULL;
return 0;
}
void cfg80211_bss_age(struct cfg80211_registered_device *dev,
unsigned long age_secs)
{
struct cfg80211_internal_bss *bss;
unsigned long age_jiffies = msecs_to_jiffies(age_secs * MSEC_PER_SEC);
spin_lock_bh(&dev->bss_lock);
list_for_each_entry(bss, &dev->bss_list, list)
bss->ts -= age_jiffies;
spin_unlock_bh(&dev->bss_lock);
}
void cfg80211_bss_expire(struct cfg80211_registered_device *dev)
{
__cfg80211_bss_expire(dev, jiffies - IEEE80211_SCAN_RESULT_EXPIRE);
}
const u8 *cfg80211_find_ie(u8 eid, const u8 *ies, int len)
{
while (len > 2 && ies[0] != eid) {
len -= ies[1] + 2;
ies += ies[1] + 2;
}
if (len < 2)
return NULL;
if (len < 2 + ies[1])
return NULL;
return ies;
}
EXPORT_SYMBOL(cfg80211_find_ie);
const u8 *cfg80211_find_vendor_ie(unsigned int oui, u8 oui_type,
const u8 *ies, int len)
{
struct ieee80211_vendor_ie *ie;
const u8 *pos = ies, *end = ies + len;
int ie_oui;
while (pos < end) {
pos = cfg80211_find_ie(WLAN_EID_VENDOR_SPECIFIC, pos,
end - pos);
if (!pos)
return NULL;
ie = (struct ieee80211_vendor_ie *)pos;
/* make sure we can access ie->len */
BUILD_BUG_ON(offsetof(struct ieee80211_vendor_ie, len) != 1);
if (ie->len < sizeof(*ie))
goto cont;
ie_oui = ie->oui[0] << 16 | ie->oui[1] << 8 | ie->oui[2];
if (ie_oui == oui && ie->oui_type == oui_type)
return pos;
cont:
pos += 2 + ie->len;
}
return NULL;
}
EXPORT_SYMBOL(cfg80211_find_vendor_ie);
static bool is_bss(struct cfg80211_bss *a, const u8 *bssid,
const u8 *ssid, size_t ssid_len)
{
const struct cfg80211_bss_ies *ies;
const u8 *ssidie;
if (bssid && !ether_addr_equal(a->bssid, bssid))
return false;
if (!ssid)
return true;
ies = rcu_access_pointer(a->ies);
if (!ies)
return false;
ssidie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
if (!ssidie)
return false;
if (ssidie[1] != ssid_len)
return false;
return memcmp(ssidie + 2, ssid, ssid_len) == 0;
}
/**
* enum bss_compare_mode - BSS compare mode
* @BSS_CMP_REGULAR: regular compare mode (for insertion and normal find)
* @BSS_CMP_HIDE_ZLEN: find hidden SSID with zero-length mode
* @BSS_CMP_HIDE_NUL: find hidden SSID with NUL-ed out mode
*/
enum bss_compare_mode {
BSS_CMP_REGULAR,
BSS_CMP_HIDE_ZLEN,
BSS_CMP_HIDE_NUL,
};
static int cmp_bss(struct cfg80211_bss *a,
struct cfg80211_bss *b,
enum bss_compare_mode mode)
{
const struct cfg80211_bss_ies *a_ies, *b_ies;
const u8 *ie1 = NULL;
const u8 *ie2 = NULL;
int i, r;
if (a->channel != b->channel)
return b->channel->center_freq - a->channel->center_freq;
a_ies = rcu_access_pointer(a->ies);
if (!a_ies)
return -1;
b_ies = rcu_access_pointer(b->ies);
if (!b_ies)
return 1;
if (WLAN_CAPABILITY_IS_STA_BSS(a->capability))
ie1 = cfg80211_find_ie(WLAN_EID_MESH_ID,
a_ies->data, a_ies->len);
if (WLAN_CAPABILITY_IS_STA_BSS(b->capability))
ie2 = cfg80211_find_ie(WLAN_EID_MESH_ID,
b_ies->data, b_ies->len);
if (ie1 && ie2) {
int mesh_id_cmp;
if (ie1[1] == ie2[1])
mesh_id_cmp = memcmp(ie1 + 2, ie2 + 2, ie1[1]);
else
mesh_id_cmp = ie2[1] - ie1[1];
ie1 = cfg80211_find_ie(WLAN_EID_MESH_CONFIG,
a_ies->data, a_ies->len);
ie2 = cfg80211_find_ie(WLAN_EID_MESH_CONFIG,
b_ies->data, b_ies->len);
if (ie1 && ie2) {
if (mesh_id_cmp)
return mesh_id_cmp;
if (ie1[1] != ie2[1])
return ie2[1] - ie1[1];
return memcmp(ie1 + 2, ie2 + 2, ie1[1]);
}
}
/*
* we can't use compare_ether_addr here since we need a < > operator.
* The binary return value of compare_ether_addr isn't enough
*/
r = memcmp(a->bssid, b->bssid, sizeof(a->bssid));
if (r)
return r;
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;
/*
* 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 */
if (!ie1)
return -1;
if (!ie2)
return 1;
switch (mode) {
case BSS_CMP_HIDE_ZLEN:
/*
* In ZLEN mode we assume the BSS entry we're
* looking for has a zero-length SSID. So if
* the one we're looking at right now has that,
* return 0. Otherwise, return the difference
* in length, but since we're looking for the
* 0-length it's really equivalent to returning
* the length of the one we're looking at.
*
* No content comparison is needed as we assume
* the content length is zero.
*/
return ie2[1];
case BSS_CMP_REGULAR:
default:
/* sort by length first, then by contents */
if (ie1[1] != ie2[1])
return ie2[1] - ie1[1];
return memcmp(ie1 + 2, ie2 + 2, ie1[1]);
case BSS_CMP_HIDE_NUL:
if (ie1[1] != ie2[1])
return ie2[1] - ie1[1];
/* this is equivalent to memcmp(zeroes, ie2 + 2, len) */
for (i = 0; i < ie2[1]; i++)
if (ie2[i + 2])
return -1;
return 0;
}
}
/* Returned bss is reference counted and must be cleaned up appropriately. */
struct cfg80211_bss *cfg80211_get_bss(struct wiphy *wiphy,
struct ieee80211_channel *channel,
const u8 *bssid,
const u8 *ssid, size_t ssid_len,
u16 capa_mask, u16 capa_val)
{
struct cfg80211_registered_device *dev = wiphy_to_dev(wiphy);
struct cfg80211_internal_bss *bss, *res = NULL;
unsigned long now = jiffies;
trace_cfg80211_get_bss(wiphy, channel, bssid, ssid, ssid_len, capa_mask,
capa_val);
spin_lock_bh(&dev->bss_lock);
list_for_each_entry(bss, &dev->bss_list, list) {
if ((bss->pub.capability & capa_mask) != capa_val)
continue;
if (channel && bss->pub.channel != channel)
continue;
/* Don't get expired BSS structs */
if (time_after(now, bss->ts + IEEE80211_SCAN_RESULT_EXPIRE) &&
!atomic_read(&bss->hold))
continue;
if (is_bss(&bss->pub, bssid, ssid, ssid_len)) {
res = bss;
bss_ref_get(dev, res);
break;
}
}
spin_unlock_bh(&dev->bss_lock);
if (!res)
return NULL;
trace_cfg80211_return_bss(&res->pub);
return &res->pub;
}
EXPORT_SYMBOL(cfg80211_get_bss);
static void rb_insert_bss(struct cfg80211_registered_device *dev,
struct cfg80211_internal_bss *bss)
{
struct rb_node **p = &dev->bss_tree.rb_node;
struct rb_node *parent = NULL;
struct cfg80211_internal_bss *tbss;
int cmp;
while (*p) {
parent = *p;
tbss = rb_entry(parent, struct cfg80211_internal_bss, rbn);
cmp = cmp_bss(&bss->pub, &tbss->pub, BSS_CMP_REGULAR);
if (WARN_ON(!cmp)) {
/* will sort of leak this BSS */
return;
}
if (cmp < 0)
p = &(*p)->rb_left;
else
p = &(*p)->rb_right;
}
rb_link_node(&bss->rbn, parent, p);
rb_insert_color(&bss->rbn, &dev->bss_tree);
}
static struct cfg80211_internal_bss *
rb_find_bss(struct cfg80211_registered_device *dev,
struct cfg80211_internal_bss *res,
enum bss_compare_mode mode)
{
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, mode);
if (r == 0)
return bss;
else if (r < 0)
n = n->rb_left;
else
n = n->rb_right;
}
return NULL;
}
static bool cfg80211_combine_bsses(struct cfg80211_registered_device *dev,
struct cfg80211_internal_bss *new)
{
const struct cfg80211_bss_ies *ies;
struct cfg80211_internal_bss *bss;
const u8 *ie;
int i, ssidlen;
u8 fold = 0;
ies = rcu_access_pointer(new->pub.beacon_ies);
if (WARN_ON(!ies))
return false;
ie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
if (!ie) {
/* nothing to do */
return true;
}
ssidlen = ie[1];
for (i = 0; i < ssidlen; i++)
fold |= ie[2 + i];
if (fold) {
/* not a hidden SSID */
return true;
}
/* This is the bad part ... */
list_for_each_entry(bss, &dev->bss_list, list) {
if (!ether_addr_equal(bss->pub.bssid, new->pub.bssid))
continue;
if (bss->pub.channel != new->pub.channel)
continue;
if (rcu_access_pointer(bss->pub.beacon_ies))
continue;
ies = rcu_access_pointer(bss->pub.ies);
if (!ies)
continue;
ie = cfg80211_find_ie(WLAN_EID_SSID, ies->data, ies->len);
if (!ie)
continue;
if (ssidlen && ie[1] != ssidlen)
continue;
/* that would be odd ... */
if (bss->pub.beacon_ies)
continue;
if (WARN_ON_ONCE(bss->pub.hidden_beacon_bss))
continue;
if (WARN_ON_ONCE(!list_empty(&bss->hidden_list)))
list_del(&bss->hidden_list);
/* combine them */
list_add(&bss->hidden_list, &new->hidden_list);
bss->pub.hidden_beacon_bss = &new->pub;
new->refcount += bss->refcount;
rcu_assign_pointer(bss->pub.beacon_ies,
new->pub.beacon_ies);
}
return true;
}
/* Returned bss is reference counted and must be cleaned up appropriately. */
static struct cfg80211_internal_bss *
cfg80211_bss_update(struct cfg80211_registered_device *dev,
struct cfg80211_internal_bss *tmp)
{
struct cfg80211_internal_bss *found = NULL;
if (WARN_ON(!tmp->pub.channel))
return NULL;
tmp->ts = jiffies;
spin_lock_bh(&dev->bss_lock);
if (WARN_ON(!rcu_access_pointer(tmp->pub.ies))) {
spin_unlock_bh(&dev->bss_lock);
return NULL;
}
found = rb_find_bss(dev, tmp, BSS_CMP_REGULAR);
if (found) {
/* Update IEs */
if (rcu_access_pointer(tmp->pub.proberesp_ies)) {
const struct cfg80211_bss_ies *old;
old = rcu_access_pointer(found->pub.proberesp_ies);
rcu_assign_pointer(found->pub.proberesp_ies,
tmp->pub.proberesp_ies);
/* Override possible earlier Beacon frame IEs */
rcu_assign_pointer(found->pub.ies,
tmp->pub.proberesp_ies);
if (old)
kfree_rcu((struct cfg80211_bss_ies *)old,
rcu_head);
} else if (rcu_access_pointer(tmp->pub.beacon_ies)) {
const struct cfg80211_bss_ies *old;
struct cfg80211_internal_bss *bss;
if (found->pub.hidden_beacon_bss &&
!list_empty(&found->hidden_list)) {
const struct cfg80211_bss_ies *f;
/*
* The found BSS struct is one of the probe
* response members of a group, but we're
* receiving a beacon (beacon_ies in the tmp
* bss is used). This can only mean that the
* AP changed its beacon from not having an
* SSID to showing it, which is confusing so
* drop this information.
*/
f = rcu_access_pointer(tmp->pub.beacon_ies);
kfree_rcu((struct cfg80211_bss_ies *)f,
rcu_head);
goto drop;
}
old = rcu_access_pointer(found->pub.beacon_ies);
rcu_assign_pointer(found->pub.beacon_ies,
tmp->pub.beacon_ies);
/* Override IEs if they were from a beacon before */
if (old == rcu_access_pointer(found->pub.ies))
rcu_assign_pointer(found->pub.ies,
tmp->pub.beacon_ies);
/* Assign beacon IEs to all sub entries */
list_for_each_entry(bss, &found->hidden_list,
hidden_list) {
const struct cfg80211_bss_ies *ies;
ies = rcu_access_pointer(bss->pub.beacon_ies);
WARN_ON(ies != old);
rcu_assign_pointer(bss->pub.beacon_ies,
tmp->pub.beacon_ies);
}
if (old)
kfree_rcu((struct cfg80211_bss_ies *)old,
rcu_head);
}
found->pub.beacon_interval = tmp->pub.beacon_interval;
found->pub.signal = tmp->pub.signal;
found->pub.capability = tmp->pub.capability;
found->ts = tmp->ts;
} else {
struct cfg80211_internal_bss *new;
struct cfg80211_internal_bss *hidden;
struct cfg80211_bss_ies *ies;
/*
* create a copy -- the "res" variable that is passed in
* is allocated on the stack since it's not needed in the
* more common case of an update
*/
new = kzalloc(sizeof(*new) + dev->wiphy.bss_priv_size,
GFP_ATOMIC);
if (!new) {
ies = (void *)rcu_dereference(tmp->pub.beacon_ies);
if (ies)
kfree_rcu(ies, rcu_head);
ies = (void *)rcu_dereference(tmp->pub.proberesp_ies);
if (ies)
kfree_rcu(ies, rcu_head);
goto drop;
}
memcpy(new, tmp, sizeof(*new));
new->refcount = 1;
INIT_LIST_HEAD(&new->hidden_list);
if (rcu_access_pointer(tmp->pub.proberesp_ies)) {
hidden = rb_find_bss(dev, tmp, BSS_CMP_HIDE_ZLEN);
if (!hidden)
hidden = rb_find_bss(dev, tmp,
BSS_CMP_HIDE_NUL);
if (hidden) {
new->pub.hidden_beacon_bss = &hidden->pub;
list_add(&new->hidden_list,
&hidden->hidden_list);
hidden->refcount++;
rcu_assign_pointer(new->pub.beacon_ies,
hidden->pub.beacon_ies);
}
} else {
/*
* Ok so we found a beacon, and don't have an entry. If
* it's a beacon with hidden SSID, we might be in for an
* expensive search for any probe responses that should
* be grouped with this beacon for updates ...
*/
if (!cfg80211_combine_bsses(dev, new)) {
kfree(new);
goto drop;
}
}
list_add_tail(&new->list, &dev->bss_list);
rb_insert_bss(dev, new);
found = new;
}
dev->bss_generation++;
bss_ref_get(dev, found);
spin_unlock_bh(&dev->bss_lock);
return found;
drop:
spin_unlock_bh(&dev->bss_lock);
return NULL;
}
static struct ieee80211_channel *
cfg80211_get_bss_channel(struct wiphy *wiphy, const u8 *ie, size_t ielen,
struct ieee80211_channel *channel)
{
const u8 *tmp;
u32 freq;
int channel_number = -1;
tmp = cfg80211_find_ie(WLAN_EID_DS_PARAMS, ie, ielen);
if (tmp && tmp[1] == 1) {
channel_number = tmp[2];
} else {
tmp = cfg80211_find_ie(WLAN_EID_HT_OPERATION, ie, ielen);
if (tmp && tmp[1] >= sizeof(struct ieee80211_ht_operation)) {
struct ieee80211_ht_operation *htop = (void *)(tmp + 2);
channel_number = htop->primary_chan;
}
}
if (channel_number < 0)
return channel;
freq = ieee80211_channel_to_frequency(channel_number, channel->band);
channel = ieee80211_get_channel(wiphy, freq);
if (!channel)
return NULL;
if (channel->flags & IEEE80211_CHAN_DISABLED)
return NULL;
return channel;
}
/* Returned bss is reference counted and must be cleaned up appropriately. */
struct cfg80211_bss*
cfg80211_inform_bss(struct wiphy *wiphy,
struct ieee80211_channel *channel,
const u8 *bssid, u64 tsf, u16 capability,
u16 beacon_interval, const u8 *ie, size_t ielen,
s32 signal, gfp_t gfp)
{
struct cfg80211_bss_ies *ies;
struct cfg80211_internal_bss tmp = {}, *res;
if (WARN_ON(!wiphy))
return NULL;
if (WARN_ON(wiphy->signal_type == CFG80211_SIGNAL_TYPE_UNSPEC &&
(signal < 0 || signal > 100)))
return NULL;
channel = cfg80211_get_bss_channel(wiphy, ie, ielen, channel);
if (!channel)
return NULL;
memcpy(tmp.pub.bssid, bssid, ETH_ALEN);
tmp.pub.channel = channel;
tmp.pub.signal = signal;
tmp.pub.beacon_interval = beacon_interval;
tmp.pub.capability = capability;
/*
* Since we do not know here whether the IEs are from a Beacon or Probe
* Response frame, we need to pick one of the options and only use it
* with the driver that does not provide the full Beacon/Probe Response
* frame. Use Beacon frame pointer to avoid indicating that this should
* override the IEs pointer should we have received an earlier
* indication of Probe Response data.
*/
ies = kmalloc(sizeof(*ies) + ielen, gfp);
if (!ies)
return NULL;
ies->len = ielen;
ies->tsf = tsf;
memcpy(ies->data, ie, ielen);
rcu_assign_pointer(tmp.pub.beacon_ies, ies);
rcu_assign_pointer(tmp.pub.ies, ies);
res = cfg80211_bss_update(wiphy_to_dev(wiphy), &tmp);
if (!res)
return NULL;
if (res->pub.capability & WLAN_CAPABILITY_ESS)
regulatory_hint_found_beacon(wiphy, channel, gfp);
trace_cfg80211_return_bss(&res->pub);
/* cfg80211_bss_update gives us a referenced result */
return &res->pub;
}
EXPORT_SYMBOL(cfg80211_inform_bss);
/* Returned bss is reference counted and must be cleaned up appropriately. */
struct cfg80211_bss *
cfg80211_inform_bss_frame(struct wiphy *wiphy,
struct ieee80211_channel *channel,
struct ieee80211_mgmt *mgmt, size_t len,
s32 signal, gfp_t gfp)
{
struct cfg80211_internal_bss tmp = {}, *res;
struct cfg80211_bss_ies *ies;
size_t ielen = len - offsetof(struct ieee80211_mgmt,
u.probe_resp.variable);
BUILD_BUG_ON(offsetof(struct ieee80211_mgmt, u.probe_resp.variable) !=
offsetof(struct ieee80211_mgmt, u.beacon.variable));
trace_cfg80211_inform_bss_frame(wiphy, channel, mgmt, len, signal);
if (WARN_ON(!mgmt))
return NULL;
if (WARN_ON(!wiphy))
return NULL;
if (WARN_ON(wiphy->signal_type == CFG80211_SIGNAL_TYPE_UNSPEC &&
(signal < 0 || signal > 100)))
return NULL;
if (WARN_ON(len < offsetof(struct ieee80211_mgmt, u.probe_resp.variable)))
return NULL;
channel = cfg80211_get_bss_channel(wiphy, mgmt->u.beacon.variable,
ielen, channel);
if (!channel)
return NULL;
ies = kmalloc(sizeof(*ies) + ielen, gfp);
if (!ies)
return NULL;
ies->len = ielen;
ies->tsf = le64_to_cpu(mgmt->u.probe_resp.timestamp);
memcpy(ies->data, mgmt->u.probe_resp.variable, ielen);
if (ieee80211_is_probe_resp(mgmt->frame_control))
rcu_assign_pointer(tmp.pub.proberesp_ies, ies);
else
rcu_assign_pointer(tmp.pub.beacon_ies, ies);
rcu_assign_pointer(tmp.pub.ies, ies);
memcpy(tmp.pub.bssid, mgmt->bssid, ETH_ALEN);
tmp.pub.channel = channel;
tmp.pub.signal = signal;
tmp.pub.beacon_interval = le16_to_cpu(mgmt->u.probe_resp.beacon_int);
tmp.pub.capability = le16_to_cpu(mgmt->u.probe_resp.capab_info);
res = cfg80211_bss_update(wiphy_to_dev(wiphy), &tmp);
if (!res)
return NULL;
if (res->pub.capability & WLAN_CAPABILITY_ESS)
regulatory_hint_found_beacon(wiphy, channel, gfp);
trace_cfg80211_return_bss(&res->pub);
/* cfg80211_bss_update gives us a referenced result */
return &res->pub;
}
EXPORT_SYMBOL(cfg80211_inform_bss_frame);
void cfg80211_ref_bss(struct wiphy *wiphy, struct cfg80211_bss *pub)
{
struct cfg80211_registered_device *dev = wiphy_to_dev(wiphy);
struct cfg80211_internal_bss *bss;