/* * cfg80211 scan result handling * * Copyright 2008 Johannes Berg */ #include #include #include #include #include #include #include #include #include #include #include #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. */ /* * Limit the number of BSS entries stored in mac80211. Each one is * a bit over 4k at most, so this limits to roughly 4-5M of memory. * If somebody wants to really attack this though, they'd likely * use small beacons, and only one type of frame, limiting each of * the entries to a much smaller size (in order to generate more * entries in total, so overhead is bigger.) */ static int bss_entries_limit = 1000; module_param(bss_entries_limit, int, 0644); MODULE_PARM_DESC(bss_entries_limit, "limit to number of scan BSS entries (per wiphy, default 1000)"); #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); dev->bss_entries--; WARN_ONCE((dev->bss_entries == 0) ^ list_empty(&dev->bss_list), "rdev bss entries[%d]/list[empty:%d] corruption\n", dev->bss_entries, list_empty(&dev->bss_list)); 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 lockdep_assert_held(&rdev->sched_scan_mtx); 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); mutex_lock(&rdev->sched_scan_mtx); ___cfg80211_scan_done(rdev, false); mutex_unlock(&rdev->sched_scan_mtx); } 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; 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); mutex_lock(&rdev->sched_scan_mtx); request = rdev->sched_scan_req; /* 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); } mutex_unlock(&rdev->sched_scan_mtx); } 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); mutex_lock(&rdev->sched_scan_mtx); __cfg80211_stop_sched_scan(rdev, true); mutex_unlock(&rdev->sched_scan_mtx); } EXPORT_SYMBOL(cfg80211_sched_scan_stopped); int __cfg80211_stop_sched_scan(struct cfg80211_registered_device *rdev, bool driver_initiated) { struct net_device *dev; lockdep_assert_held(&rdev->sched_scan_mtx); 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); } static bool cfg80211_bss_expire_oldest(struct cfg80211_registered_device *rdev) { struct cfg80211_internal_bss *bss, *oldest = NULL; bool ret; lockdep_assert_held(&rdev->bss_lock); list_for_each_entry(bss, &rdev->bss_list, list) { if (atomic_read(&bss->hold)) continue; if (!list_empty(&bss->hidden_list) && !bss->pub.hidden_beacon_bss) continue; if (oldest && time_before(oldest->ts, bss->ts)) continue; oldest = bss; } if (WARN_ON(!oldest)) return false; /* * The callers make sure to increase rdev->bss_generation if anything * gets removed (and a new entry added), so there's no need to also do * it here. */ ret = __cfg80211_unlink_bss(rdev, oldest); WARN_ON(!ret); return ret; } 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; } } 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; u32 n_entries = 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) { /* * we're iterating all the entries anyway, so take the * opportunity to validate the list length accounting */ n_entries++; 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); } WARN_ONCE(n_entries != dev->bss_entries, "rdev bss entries[%d]/list[len:%d] corruption\n", dev->bss_entries, n_entries); return true; } 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; } } if (dev->bss_entries >= bss_entries_limit && !cfg80211_bss_expire_oldest(dev)) { kfree(new); goto drop; } list_add_tail(&new->list, &dev->bss_list); dev->bss_entries++; 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; } 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); 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; if (!pub) return; bss = container_of(pub, struct cfg80211_internal_bss, pub); spin_lock_bh(&dev->bss_lock); bss_ref_get(dev, bss); spin_unlock_bh(&dev->bss_lock); } EXPORT_SYMBOL(cfg80211_ref_bss); void cfg80211_put_bss(struct wiphy *wiphy, struct cfg80211_bss *pub) { struct cfg80211_registered_device *dev = wiphy_to_dev(wiphy); struct cfg80211_internal_bss *bss; if (!pub) return; bss = container_of(pub, struct cfg80211_internal_bss, pub); spin_lock_bh(&dev->bss_lock); bss_ref_put(dev, bss); spin_unlock_bh(&dev->bss_lock); } EXPORT_SYMBOL(cfg80211_put_bss); void cfg80211_unlink_bss(struct wiphy *wiphy, struct cfg80211_bss *pub) { struct cfg80211_registered_device *dev = wiphy_to_dev(wiphy); struct cfg80211_internal_bss *bss; if (WARN_ON(!pub)) return; bss = container_of(pub, struct cfg80211_internal_bss, pub); spin_lock_bh(&dev->bss_lock); if (!list_empty(&bss->list)) { if (__cfg80211_unlink_bss(dev, bss)) dev->bss_generation++; } spin_unlock_bh(&dev->bss_lock); } EXPORT_SYMBOL(cfg80211_unlink_bss); #ifdef CONFIG_CFG80211_WEXT int cfg80211_wext_siwscan(struct net_device *dev, struct iw_request_info *info, union iwreq_data *wrqu, char *extra) { struct cfg80211_registered_device *rdev; struct wiphy *wiphy; struct iw_scan_req *wreq = NULL; struct cfg80211_scan_request *creq = NULL; int i, err, n_channels = 0; enum ieee80211_band band; if (!netif_running(dev)) return -ENETDOWN; if (wrqu->data.length == sizeof(struct iw_scan_req)) wreq = (struct iw_scan_req *)extra; rdev = cfg80211_get_dev_from_ifindex(dev_net(dev), dev->ifindex); if (IS_ERR(rdev)) return PTR_ERR(rdev); mutex_lock(&rdev->sched_scan_mtx); if (rdev->scan_req) { err = -EBUSY; goto out; } wiphy = &rdev->wiphy; /* Determine number of channels, needed to allocate creq */ if (wreq && wreq->num_channels) n_channels = wreq->num_channels; else { for (band = 0; band < IEEE80211_NUM_BANDS; band++) if (wiphy->bands[band]) n_channels += wiphy->bands[band]->n_channels; } creq = kzalloc(sizeof(*creq) + sizeof(struct cfg80211_ssid) + n_channels * sizeof(void *), GFP_ATOMIC); if (!creq) { err = -ENOMEM; goto out; } creq->wiphy = wiphy; creq->wdev = dev->ieee80211_ptr; /* SSIDs come after channels */ creq->ssids = (void *)&creq->channels[n_channels]; creq->n_channels = n_channels; creq->n_ssids = 1; creq->scan_start = jiffies; /* translate "Scan on frequencies" request */ i = 0; for (band = 0; band < IEEE80211_NUM_BANDS; band++) { int j; if (!wiphy->bands[band]) continue; for (j = 0; j < wiphy->bands[band]->n_channels; j++) { /* ignore disabled channels */ if (wiphy->bands[band]->channels[j].flags & IEEE80211_CHAN_DISABLED) continue; /* If we have a wireless request structure and the * wireless request specifies frequencies, then search * for the matching hardware channel. */ if (wreq && wreq->num_channels) { int k; int wiphy_freq = wiphy->bands[band]->channels[j].center_freq; for (k = 0; k < wreq->num_channels; k++) { int wext_freq = cfg80211_wext_freq(wiphy, &wreq->channel_list[k]); if (wext_freq == wiphy_freq) goto wext_freq_found; } goto wext_freq_not_found; } wext_freq_found: creq->channels[i] = &wiphy->bands[band]->channels[j]; i++; wext_freq_not_found: ; } } /* No channels found? */ if (!i) { err = -EINVAL; goto out; } /* Set real number of channels specified in creq->channels[] */ creq->n_channels = i; /* translate "Scan for SSID" request */ if (wreq) { if (wrqu->data.flags & IW_SCAN_THIS_ESSID) { if (wreq->essid_len > IEEE80211_MAX_SSID_LEN) { err = -EINVAL; goto out; } memcpy(creq->ssids[0].ssid, wreq->essid, wreq->essid_len); creq->ssids[0].ssid_len = wreq->essid_len; } if (wreq->scan_type == IW_SCAN_TYPE_PASSIVE) creq->n_ssids = 0; } for (i = 0; i < IEEE80211_NUM_BANDS; i++) if (wiphy->bands[i]) creq->rates[i] = (1 << wiphy->bands[i]->n_bitrates) - 1; rdev->scan_req = creq; err = rdev_scan(rdev, creq); if (err) { rdev->scan_req = NULL; /* creq will be freed below */ } else { nl80211_send_scan_start(rdev, dev->ieee80211_ptr); /* creq now owned by driver */ creq = NULL; dev_hold(dev); } out: mutex_unlock(&rdev->sched_scan_mtx); kfree(creq); cfg80211_unlock_rdev(rdev); return err; } EXPORT_SYMBOL_GPL(cfg80211_wext_siwscan); static void ieee80211_scan_add_ies(struct iw_request_info *info, const struct cfg80211_bss_ies *ies, char **current_ev, char *end_buf) { const u8 *pos, *end, *next; struct iw_event iwe; if (!ies) return; /* * If needed, fragment the IEs buffer (at IE boundaries) into short * enough fragments to fit into IW_GENERIC_IE_MAX octet messages. */ pos = ies->data; end = pos + ies->len; while (end - pos > IW_GENERIC_IE_MAX) { next = pos + 2 + pos[1]; while (next + 2 + next[1] - pos < IW_GENERIC_IE_MAX) next = next + 2 + next[1]; memset(&iwe, 0, sizeof(iwe)); iwe.cmd = IWEVGENIE; iwe.u.data.length = next - pos; *current_ev = iwe_stream_add_point(info, *current_ev, end_buf, &iwe, (void *)pos); pos = next; } if (end > pos) { memset(&iwe, 0, sizeof(iwe)); iwe.cmd = IWEVGENIE; iwe.u.data.length = end - pos; *current_ev = iwe_stream_add_point(info, *current_ev, end_buf, &iwe, (void *)pos); } } static char * ieee80211_bss(struct wiphy *wiphy, struct iw_request_info *info, struct cfg80211_internal_bss *bss, char *current_ev, char *end_buf) { const struct cfg80211_bss_ies *ies; struct iw_event iwe; const u8 *ie; u8 *buf, *cfg, *p; int rem, i, sig; bool ismesh = false; memset(&iwe, 0, sizeof(iwe)); iwe.cmd = SIOCGIWAP; iwe.u.ap_addr.sa_family = ARPHRD_ETHER; memcpy(iwe.u.ap_addr.sa_data, bss->pub.bssid, ETH_ALEN); current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe, IW_EV_ADDR_LEN); memset(&iwe, 0, sizeof(iwe)); iwe.cmd = SIOCGIWFREQ; iwe.u.freq.m = ieee80211_frequency_to_channel(bss->pub.channel->center_freq); iwe.u.freq.e = 0; current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe, IW_EV_FREQ_LEN); memset(&iwe, 0, sizeof(iwe)); iwe.cmd = SIOCGIWFREQ; iwe.u.freq.m = bss->pub.channel->center_freq; iwe.u.freq.e = 6; current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe, IW_EV_FREQ_LEN); if (wiphy->signal_type != CFG80211_SIGNAL_TYPE_NONE) { memset(&iwe, 0, sizeof(iwe)); iwe.cmd = IWEVQUAL; iwe.u.qual.updated = IW_QUAL_LEVEL_UPDATED | IW_QUAL_NOISE_INVALID | IW_QUAL_QUAL_UPDATED; switch (wiphy->signal_type) { case CFG80211_SIGNAL_TYPE_MBM: sig = bss->pub.signal / 100; iwe.u.qual.level = sig; iwe.u.qual.updated |= IW_QUAL_DBM; if (sig < -110) /* rather bad */ sig = -110; else if (sig > -40) /* perfect */ sig = -40; /* will give a range of 0 .. 70 */ iwe.u.qual.qual = sig + 110; break; case CFG80211_SIGNAL_TYPE_UNSPEC: iwe.u.qual.level = bss->pub.signal; /* will give range 0 .. 100 */ iwe.u.qual.qual = bss->pub.signal; break; default: /* not reached */ break; } current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe, IW_EV_QUAL_LEN); } memset(&iwe, 0, sizeof(iwe)); iwe.cmd = SIOCGIWENCODE; if (bss->pub.capability & WLAN_CAPABILITY_PRIVACY) iwe.u.data.flags = IW_ENCODE_ENABLED | IW_ENCODE_NOKEY; else iwe.u.data.flags = IW_ENCODE_DISABLED; iwe.u.data.length = 0; current_ev = iwe_stream_add_point(info, current_ev, end_buf, &iwe, ""); rcu_read_lock(); ies = rcu_dereference(bss->pub.ies); rem = ies->len; ie = ies->data; while (rem >= 2) { /* invalid data */ if (ie[1] > rem - 2) break; switch (ie[0]) { case WLAN_EID_SSID: memset(&iwe, 0, sizeof(iwe)); iwe.cmd = SIOCGIWESSID; iwe.u.data.length = ie[1]; iwe.u.data.flags = 1; current_ev = iwe_stream_add_point(info, current_ev, end_buf, &iwe, (u8 *)ie + 2); break; case WLAN_EID_MESH_ID: memset(&iwe, 0, sizeof(iwe)); iwe.cmd = SIOCGIWESSID; iwe.u.data.length = ie[1]; iwe.u.data.flags = 1; current_ev = iwe_stream_add_point(info, current_ev, end_buf, &iwe, (u8 *)ie + 2); break; case WLAN_EID_MESH_CONFIG: ismesh = true; if (ie[1] != sizeof(struct ieee80211_meshconf_ie)) break; buf = kmalloc(50, GFP_ATOMIC); if (!buf) break; cfg = (u8 *)ie + 2; memset(&iwe, 0, sizeof(iwe)); iwe.cmd = IWEVCUSTOM; sprintf(buf, "Mesh Network Path Selection Protocol ID: " "0x%02X", cfg[0]); iwe.u.data.length = strlen(buf); current_ev = iwe_stream_add_point(info, current_ev, end_buf, &iwe, buf); sprintf(buf, "Path Selection Metric ID: 0x%02X", cfg[1]); iwe.u.data.length = strlen(buf); current_ev = iwe_stream_add_point(info, current_ev, end_buf, &iwe, buf); sprintf(buf, "Congestion Control Mode ID: 0x%02X", cfg[2]); iwe.u.data.length = strlen(buf); current_ev = iwe_stream_add_point(info, current_ev, end_buf, &iwe, buf); sprintf(buf, "Synchronization ID: 0x%02X", cfg[3]); iwe.u.data.length = strlen(buf); current_ev = iwe_stream_add_point(info, current_ev, end_buf, &iwe, buf); sprintf(buf, "Authentication ID: 0x%02X", cfg[4]); iwe.u.data.length = strlen(buf); current_ev = iwe_stream_add_point(info, current_ev, end_buf, &iwe, buf); sprintf(buf, "Formation Info: 0x%02X", cfg[5]); iwe.u.data.length = strlen(buf); current_ev = iwe_stream_add_point(info, current_ev, end_buf, &iwe, buf); sprintf(buf, "Capabilities: 0x%02X", cfg[6]); iwe.u.data.length = strlen(buf); current_ev = iwe_stream_add_point(info, current_ev, end_buf, &iwe, buf); kfree(buf); break; case WLAN_EID_SUPP_RATES: case WLAN_EID_EXT_SUPP_RATES: /* display all supported rates in readable format */ p = current_ev + iwe_stream_lcp_len(info); memset(&iwe, 0, sizeof(iwe)); iwe.cmd = SIOCGIWRATE; /* Those two flags are ignored... */ iwe.u.bitrate.fixed = iwe.u.bitrate.disabled = 0; for (i = 0; i < ie[1]; i++) { iwe.u.bitrate.value = ((ie[i + 2] & 0x7f) * 500000); p = iwe_stream_add_value(info, current_ev, p, end_buf, &iwe, IW_EV_PARAM_LEN); } current_ev = p; break; } rem -= ie[1] + 2; ie += ie[1] + 2; } if (bss->pub.capability & (WLAN_CAPABILITY_ESS | WLAN_CAPABILITY_IBSS) || ismesh) { memset(&iwe, 0, sizeof(iwe)); iwe.cmd = SIOCGIWMODE; if (ismesh) iwe.u.mode = IW_MODE_MESH; else if (bss->pub.capability & WLAN_CAPABILITY_ESS) iwe.u.mode = IW_MODE_MASTER; else iwe.u.mode = IW_MODE_ADHOC; current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe, IW_EV_UINT_LEN); } buf = kmalloc(31, GFP_ATOMIC); if (buf) { memset(&iwe, 0, sizeof(iwe)); iwe.cmd = IWEVCUSTOM; sprintf(buf, "tsf=%016llx", (unsigned long long)(ies->tsf)); iwe.u.data.length = strlen(buf); current_ev = iwe_stream_add_point(info, current_ev, end_buf, &iwe, buf); memset(&iwe, 0, sizeof(iwe)); iwe.cmd = IWEVCUSTOM; sprintf(buf, " Last beacon: %ums ago", elapsed_jiffies_msecs(bss->ts)); iwe.u.data.length = strlen(buf); current_ev = iwe_stream_add_point(info, current_ev, end_buf, &iwe, buf); kfree(buf); } ieee80211_scan_add_ies(info, ies, ¤t_ev, end_buf); rcu_read_unlock(); return current_ev; } static int ieee80211_scan_results(struct cfg80211_registered_device *dev, struct iw_request_info *info, char *buf, size_t len) { char *current_ev = buf; char *end_buf = buf + len; struct cfg80211_internal_bss *bss; spin_lock_bh(&dev->bss_lock); cfg80211_bss_expire(dev); list_for_each_entry(bss, &dev->bss_list, list) { if (buf + len - current_ev <= IW_EV_ADDR_LEN) { spin_unlock_bh(&dev->bss_lock); return -E2BIG; } current_ev = ieee80211_bss(&dev->wiphy, info, bss, current_ev, end_buf); } spin_unlock_bh(&dev->bss_lock); return current_ev - buf; } int cfg80211_wext_giwscan(struct net_device *dev, struct iw_request_info *info, struct iw_point *data, char *extra) { struct cfg80211_registered_device *rdev; int res; if (!netif_running(dev)) return -ENETDOWN; rdev = cfg80211_get_dev_from_ifindex(dev_net(dev), dev->ifindex); if (IS_ERR(rdev)) return PTR_ERR(rdev); if (rdev->scan_req) { res = -EAGAIN; goto out; } res = ieee80211_scan_results(rdev, info, extra, data->length); data->length = 0; if (res >= 0) { data->length = res; res = 0; } out: cfg80211_unlock_rdev(rdev); return res; } EXPORT_SYMBOL_GPL(cfg80211_wext_giwscan); #endif