/* * Scanning implementation * * Copyright 2003, Jouni Malinen * Copyright 2004, Instant802 Networks, Inc. * Copyright 2005, Devicescape Software, Inc. * Copyright 2006-2007 Jiri Benc * Copyright 2007, Michael Wu * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ /* TODO: * figure out how to avoid that the "current BSS" expires * clean up IBSS code (in MLME), see why it adds a BSS to the list * use cfg80211's BSS handling (depends on IBSS TODO above) * order BSS list by RSSI(?) ("quality of AP") * scan result table filtering (by capability (privacy, IBSS/BSS, WPA/RSN IE, * SSID) */ #include #include #include #include #include #include "ieee80211_i.h" #include "mesh.h" #define IEEE80211_PROBE_DELAY (HZ / 33) #define IEEE80211_CHANNEL_TIME (HZ / 33) #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 5) void ieee80211_rx_bss_list_init(struct ieee80211_local *local) { spin_lock_init(&local->bss_lock); INIT_LIST_HEAD(&local->bss_list); } void ieee80211_rx_bss_list_deinit(struct ieee80211_local *local) { struct ieee80211_bss *bss, *tmp; list_for_each_entry_safe(bss, tmp, &local->bss_list, list) ieee80211_rx_bss_put(local, bss); } struct ieee80211_bss * ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq, u8 *ssid, u8 ssid_len) { struct ieee80211_bss *bss; spin_lock_bh(&local->bss_lock); bss = local->bss_hash[STA_HASH(bssid)]; while (bss) { if (!bss_mesh_cfg(bss) && !memcmp(bss->bssid, bssid, ETH_ALEN) && bss->freq == freq && bss->ssid_len == ssid_len && (ssid_len == 0 || !memcmp(bss->ssid, ssid, ssid_len))) { atomic_inc(&bss->users); break; } bss = bss->hnext; } spin_unlock_bh(&local->bss_lock); return bss; } /* Caller must hold local->bss_lock */ static void __ieee80211_rx_bss_hash_add(struct ieee80211_local *local, struct ieee80211_bss *bss) { u8 hash_idx; if (bss_mesh_cfg(bss)) hash_idx = mesh_id_hash(bss_mesh_id(bss), bss_mesh_id_len(bss)); else hash_idx = STA_HASH(bss->bssid); bss->hnext = local->bss_hash[hash_idx]; local->bss_hash[hash_idx] = bss; } /* Caller must hold local->bss_lock */ static void __ieee80211_rx_bss_hash_del(struct ieee80211_local *local, struct ieee80211_bss *bss) { struct ieee80211_bss *b, *prev = NULL; b = local->bss_hash[STA_HASH(bss->bssid)]; while (b) { if (b == bss) { if (!prev) local->bss_hash[STA_HASH(bss->bssid)] = bss->hnext; else prev->hnext = bss->hnext; break; } prev = b; b = b->hnext; } } struct ieee80211_bss * ieee80211_rx_bss_add(struct ieee80211_local *local, u8 *bssid, int freq, u8 *ssid, u8 ssid_len) { struct ieee80211_bss *bss; bss = kzalloc(sizeof(*bss), GFP_ATOMIC); if (!bss) return NULL; atomic_set(&bss->users, 2); memcpy(bss->bssid, bssid, ETH_ALEN); bss->freq = freq; if (ssid && ssid_len <= IEEE80211_MAX_SSID_LEN) { memcpy(bss->ssid, ssid, ssid_len); bss->ssid_len = ssid_len; } spin_lock_bh(&local->bss_lock); /* TODO: order by RSSI? */ list_add_tail(&bss->list, &local->bss_list); __ieee80211_rx_bss_hash_add(local, bss); spin_unlock_bh(&local->bss_lock); return bss; } #ifdef CONFIG_MAC80211_MESH static struct ieee80211_bss * ieee80211_rx_mesh_bss_get(struct ieee80211_local *local, u8 *mesh_id, int mesh_id_len, u8 *mesh_cfg, int freq) { struct ieee80211_bss *bss; spin_lock_bh(&local->bss_lock); bss = local->bss_hash[mesh_id_hash(mesh_id, mesh_id_len)]; while (bss) { if (bss_mesh_cfg(bss) && !memcmp(bss_mesh_cfg(bss), mesh_cfg, MESH_CFG_CMP_LEN) && bss->freq == freq && mesh_id_len == bss->mesh_id_len && (mesh_id_len == 0 || !memcmp(bss->mesh_id, mesh_id, mesh_id_len))) { atomic_inc(&bss->users); break; } bss = bss->hnext; } spin_unlock_bh(&local->bss_lock); return bss; } static struct ieee80211_bss * ieee80211_rx_mesh_bss_add(struct ieee80211_local *local, u8 *mesh_id, int mesh_id_len, u8 *mesh_cfg, int mesh_config_len, int freq) { struct ieee80211_bss *bss; if (mesh_config_len != IEEE80211_MESH_CONFIG_LEN) return NULL; bss = kzalloc(sizeof(*bss), GFP_ATOMIC); if (!bss) return NULL; bss->mesh_cfg = kmalloc(MESH_CFG_CMP_LEN, GFP_ATOMIC); if (!bss->mesh_cfg) { kfree(bss); return NULL; } if (mesh_id_len && mesh_id_len <= IEEE80211_MAX_MESH_ID_LEN) { bss->mesh_id = kmalloc(mesh_id_len, GFP_ATOMIC); if (!bss->mesh_id) { kfree(bss->mesh_cfg); kfree(bss); return NULL; } memcpy(bss->mesh_id, mesh_id, mesh_id_len); } atomic_set(&bss->users, 2); memcpy(bss->mesh_cfg, mesh_cfg, MESH_CFG_CMP_LEN); bss->mesh_id_len = mesh_id_len; bss->freq = freq; spin_lock_bh(&local->bss_lock); /* TODO: order by RSSI? */ list_add_tail(&bss->list, &local->bss_list); __ieee80211_rx_bss_hash_add(local, bss); spin_unlock_bh(&local->bss_lock); return bss; } #endif static void ieee80211_rx_bss_free(struct ieee80211_bss *bss) { kfree(bss->ies); kfree(bss_mesh_id(bss)); kfree(bss_mesh_cfg(bss)); kfree(bss); } void ieee80211_rx_bss_put(struct ieee80211_local *local, struct ieee80211_bss *bss) { local_bh_disable(); if (!atomic_dec_and_lock(&bss->users, &local->bss_lock)) { local_bh_enable(); return; } __ieee80211_rx_bss_hash_del(local, bss); list_del(&bss->list); spin_unlock_bh(&local->bss_lock); ieee80211_rx_bss_free(bss); } struct ieee80211_bss * ieee80211_bss_info_update(struct ieee80211_local *local, struct ieee80211_rx_status *rx_status, struct ieee80211_mgmt *mgmt, size_t len, struct ieee802_11_elems *elems, struct ieee80211_channel *channel, bool beacon) { struct ieee80211_bss *bss; int clen, freq = channel->center_freq; enum cfg80211_signal_type sigtype = CFG80211_SIGNAL_TYPE_NONE; s32 signal = 0; if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) { sigtype = CFG80211_SIGNAL_TYPE_MBM; signal = rx_status->signal * 100; } else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC) { sigtype = CFG80211_SIGNAL_TYPE_UNSPEC; signal = (rx_status->signal * 100) / local->hw.max_signal; } cfg80211_put_bss( cfg80211_inform_bss_frame(local->hw.wiphy, channel, mgmt, len, signal, sigtype, GFP_ATOMIC)); #ifdef CONFIG_MAC80211_MESH if (elems->mesh_config) bss = ieee80211_rx_mesh_bss_get(local, elems->mesh_id, elems->mesh_id_len, elems->mesh_config, freq); else #endif bss = ieee80211_rx_bss_get(local, mgmt->bssid, freq, elems->ssid, elems->ssid_len); if (!bss) { #ifdef CONFIG_MAC80211_MESH if (elems->mesh_config) bss = ieee80211_rx_mesh_bss_add(local, elems->mesh_id, elems->mesh_id_len, elems->mesh_config, elems->mesh_config_len, freq); else #endif bss = ieee80211_rx_bss_add(local, mgmt->bssid, freq, elems->ssid, elems->ssid_len); if (!bss) return NULL; } else { #if 0 /* TODO: order by RSSI? */ spin_lock_bh(&local->bss_lock); list_move_tail(&bss->list, &local->bss_list); spin_unlock_bh(&local->bss_lock); #endif } /* save the ERP value so that it is available at association time */ if (elems->erp_info && elems->erp_info_len >= 1) { bss->erp_value = elems->erp_info[0]; bss->has_erp_value = 1; } bss->beacon_int = le16_to_cpu(mgmt->u.beacon.beacon_int); bss->capability = le16_to_cpu(mgmt->u.beacon.capab_info); if (elems->tim) { struct ieee80211_tim_ie *tim_ie = (struct ieee80211_tim_ie *)elems->tim; bss->dtim_period = tim_ie->dtim_period; } /* set default value for buggy APs */ if (!elems->tim || bss->dtim_period == 0) bss->dtim_period = 1; bss->supp_rates_len = 0; if (elems->supp_rates) { clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len; if (clen > elems->supp_rates_len) clen = elems->supp_rates_len; memcpy(&bss->supp_rates[bss->supp_rates_len], elems->supp_rates, clen); bss->supp_rates_len += clen; } if (elems->ext_supp_rates) { clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len; if (clen > elems->ext_supp_rates_len) clen = elems->ext_supp_rates_len; memcpy(&bss->supp_rates[bss->supp_rates_len], elems->ext_supp_rates, clen); bss->supp_rates_len += clen; } bss->band = rx_status->band; bss->timestamp = le64_to_cpu(mgmt->u.beacon.timestamp); bss->last_update = jiffies; bss->signal = rx_status->signal; bss->noise = rx_status->noise; bss->qual = rx_status->qual; bss->wmm_used = elems->wmm_param || elems->wmm_info; if (!beacon) bss->last_probe_resp = jiffies; /* * For probe responses, or if we don't have any information yet, * use the IEs from the beacon. */ if (!bss->ies || !beacon) { if (bss->ies == NULL || bss->ies_len < elems->total_len) { kfree(bss->ies); bss->ies = kmalloc(elems->total_len, GFP_ATOMIC); } if (bss->ies) { memcpy(bss->ies, elems->ie_start, elems->total_len); bss->ies_len = elems->total_len; } else bss->ies_len = 0; } return bss; } void ieee80211_rx_bss_remove(struct ieee80211_sub_if_data *sdata, u8 *bssid, int freq, u8 *ssid, u8 ssid_len) { struct ieee80211_bss *bss; struct ieee80211_local *local = sdata->local; bss = ieee80211_rx_bss_get(local, bssid, freq, ssid, ssid_len); if (bss) { atomic_dec(&bss->users); ieee80211_rx_bss_put(local, bss); } } ieee80211_rx_result ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb, struct ieee80211_rx_status *rx_status) { struct ieee80211_mgmt *mgmt; struct ieee80211_bss *bss; u8 *elements; struct ieee80211_channel *channel; size_t baselen; int freq; __le16 fc; bool presp, beacon = false; struct ieee802_11_elems elems; if (skb->len < 2) return RX_DROP_UNUSABLE; mgmt = (struct ieee80211_mgmt *) skb->data; fc = mgmt->frame_control; if (ieee80211_is_ctl(fc)) return RX_CONTINUE; if (skb->len < 24) return RX_DROP_MONITOR; presp = ieee80211_is_probe_resp(fc); if (presp) { /* ignore ProbeResp to foreign address */ if (memcmp(mgmt->da, sdata->dev->dev_addr, ETH_ALEN)) return RX_DROP_MONITOR; presp = true; elements = mgmt->u.probe_resp.variable; baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable); } else { beacon = ieee80211_is_beacon(fc); baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable); elements = mgmt->u.beacon.variable; } if (!presp && !beacon) return RX_CONTINUE; if (baselen > skb->len) return RX_DROP_MONITOR; ieee802_11_parse_elems(elements, skb->len - baselen, &elems); if (elems.ds_params && elems.ds_params_len == 1) freq = ieee80211_channel_to_frequency(elems.ds_params[0]); else freq = rx_status->freq; channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq); if (!channel || channel->flags & IEEE80211_CHAN_DISABLED) return RX_DROP_MONITOR; bss = ieee80211_bss_info_update(sdata->local, rx_status, mgmt, skb->len, &elems, channel, beacon); if (bss) ieee80211_rx_bss_put(sdata->local, bss); dev_kfree_skb(skb); return RX_QUEUED; } void ieee80211_send_nullfunc(struct ieee80211_local *local, struct ieee80211_sub_if_data *sdata, int powersave) { struct sk_buff *skb; struct ieee80211_hdr *nullfunc; __le16 fc; skb = dev_alloc_skb(local->hw.extra_tx_headroom + 24); if (!skb) { printk(KERN_DEBUG "%s: failed to allocate buffer for nullfunc " "frame\n", sdata->dev->name); return; } skb_reserve(skb, local->hw.extra_tx_headroom); nullfunc = (struct ieee80211_hdr *) skb_put(skb, 24); memset(nullfunc, 0, 24); fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_NULLFUNC | IEEE80211_FCTL_TODS); if (powersave) fc |= cpu_to_le16(IEEE80211_FCTL_PM); nullfunc->frame_control = fc; memcpy(nullfunc->addr1, sdata->u.sta.bssid, ETH_ALEN); memcpy(nullfunc->addr2, sdata->dev->dev_addr, ETH_ALEN); memcpy(nullfunc->addr3, sdata->u.sta.bssid, ETH_ALEN); ieee80211_tx_skb(sdata, skb, 0); } void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) { struct ieee80211_local *local = hw_to_local(hw); struct ieee80211_sub_if_data *sdata; if (WARN_ON(!local->hw_scanning && !local->sw_scanning)) return; if (WARN_ON(!local->scan_req)) return; if (local->scan_req != &local->int_scan_req) cfg80211_scan_done(local->scan_req, aborted); local->scan_req = NULL; local->last_scan_completed = jiffies; if (local->hw_scanning) { local->hw_scanning = false; /* * Somebody might have requested channel change during scan * that we won't have acted upon, try now. ieee80211_hw_config * will set the flag based on actual changes. */ ieee80211_hw_config(local, 0); goto done; } local->sw_scanning = false; ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); netif_tx_lock_bh(local->mdev); netif_addr_lock(local->mdev); local->filter_flags &= ~FIF_BCN_PRBRESP_PROMISC; local->ops->configure_filter(local_to_hw(local), FIF_BCN_PRBRESP_PROMISC, &local->filter_flags, local->mdev->mc_count, local->mdev->mc_list); netif_addr_unlock(local->mdev); netif_tx_unlock_bh(local->mdev); mutex_lock(&local->iflist_mtx); list_for_each_entry(sdata, &local->interfaces, list) { if (!netif_running(sdata->dev)) continue; /* Tell AP we're back */ if (sdata->vif.type == NL80211_IFTYPE_STATION) { if (sdata->u.sta.flags & IEEE80211_STA_ASSOCIATED) { ieee80211_send_nullfunc(local, sdata, 0); netif_tx_wake_all_queues(sdata->dev); } } else netif_tx_wake_all_queues(sdata->dev); /* re-enable beaconing */ if (sdata->vif.type == NL80211_IFTYPE_AP || sdata->vif.type == NL80211_IFTYPE_ADHOC || sdata->vif.type == NL80211_IFTYPE_MESH_POINT) ieee80211_if_config(sdata, IEEE80211_IFCC_BEACON_ENABLED); } mutex_unlock(&local->iflist_mtx); done: ieee80211_mlme_notify_scan_completed(local); ieee80211_mesh_notify_scan_completed(local); } EXPORT_SYMBOL(ieee80211_scan_completed); void ieee80211_scan_work(struct work_struct *work) { struct ieee80211_local *local = container_of(work, struct ieee80211_local, scan_work.work); struct ieee80211_sub_if_data *sdata = local->scan_sdata; struct ieee80211_channel *chan; int skip, i; unsigned long next_delay = 0; /* * Avoid re-scheduling when the sdata is going away. */ if (!netif_running(sdata->dev)) return; switch (local->scan_state) { case SCAN_SET_CHANNEL: /* if no more bands/channels left, complete scan */ if (local->scan_channel_idx >= local->scan_req->n_channels) { ieee80211_scan_completed(local_to_hw(local), false); return; } skip = 0; chan = local->scan_req->channels[local->scan_channel_idx]; if (chan->flags & IEEE80211_CHAN_DISABLED || (sdata->vif.type == NL80211_IFTYPE_ADHOC && chan->flags & IEEE80211_CHAN_NO_IBSS)) skip = 1; if (!skip) { local->scan_channel = chan; if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) skip = 1; } /* advance state machine to next channel/band */ local->scan_channel_idx++; if (skip) break; next_delay = IEEE80211_PROBE_DELAY + usecs_to_jiffies(local->hw.channel_change_time); local->scan_state = SCAN_SEND_PROBE; break; case SCAN_SEND_PROBE: next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; local->scan_state = SCAN_SET_CHANNEL; if (local->scan_channel->flags & IEEE80211_CHAN_PASSIVE_SCAN || !local->scan_req->n_ssids) break; for (i = 0; i < local->scan_req->n_ssids; i++) ieee80211_send_probe_req( sdata, NULL, local->scan_req->ssids[i].ssid, local->scan_req->ssids[i].ssid_len); next_delay = IEEE80211_CHANNEL_TIME; break; } queue_delayed_work(local->hw.workqueue, &local->scan_work, next_delay); } int ieee80211_start_scan(struct ieee80211_sub_if_data *scan_sdata, struct cfg80211_scan_request *req) { struct ieee80211_local *local = scan_sdata->local; struct ieee80211_sub_if_data *sdata; if (!req) return -EINVAL; if (local->scan_req && local->scan_req != req) return -EBUSY; local->scan_req = req; /* MLME-SCAN.request (page 118) page 144 (11.1.3.1) * BSSType: INFRASTRUCTURE, INDEPENDENT, ANY_BSS * BSSID: MACAddress * SSID * ScanType: ACTIVE, PASSIVE * ProbeDelay: delay (in microseconds) to be used prior to transmitting * a Probe frame during active scanning * ChannelList * MinChannelTime (>= ProbeDelay), in TU * MaxChannelTime: (>= MinChannelTime), in TU */ /* MLME-SCAN.confirm * BSSDescriptionSet * ResultCode: SUCCESS, INVALID_PARAMETERS */ if (local->sw_scanning || local->hw_scanning) { if (local->scan_sdata == scan_sdata) return 0; return -EBUSY; } if (local->ops->hw_scan) { int rc; local->hw_scanning = true; rc = local->ops->hw_scan(local_to_hw(local), req); if (rc) { local->hw_scanning = false; return rc; } local->scan_sdata = scan_sdata; return 0; } local->sw_scanning = true; mutex_lock(&local->iflist_mtx); list_for_each_entry(sdata, &local->interfaces, list) { if (!netif_running(sdata->dev)) continue; /* disable beaconing */ if (sdata->vif.type == NL80211_IFTYPE_AP || sdata->vif.type == NL80211_IFTYPE_ADHOC || sdata->vif.type == NL80211_IFTYPE_MESH_POINT) ieee80211_if_config(sdata, IEEE80211_IFCC_BEACON_ENABLED); if (sdata->vif.type == NL80211_IFTYPE_STATION) { if (sdata->u.sta.flags & IEEE80211_STA_ASSOCIATED) { netif_tx_stop_all_queues(sdata->dev); ieee80211_send_nullfunc(local, sdata, 1); } } else netif_tx_stop_all_queues(sdata->dev); } mutex_unlock(&local->iflist_mtx); local->scan_state = SCAN_SET_CHANNEL; local->scan_channel_idx = 0; local->scan_sdata = scan_sdata; local->scan_req = req; netif_addr_lock_bh(local->mdev); local->filter_flags |= FIF_BCN_PRBRESP_PROMISC; local->ops->configure_filter(local_to_hw(local), FIF_BCN_PRBRESP_PROMISC, &local->filter_flags, local->mdev->mc_count, local->mdev->mc_list); netif_addr_unlock_bh(local->mdev); /* TODO: start scan as soon as all nullfunc frames are ACKed */ queue_delayed_work(local->hw.workqueue, &local->scan_work, IEEE80211_CHANNEL_TIME); return 0; } int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, struct cfg80211_scan_request *req) { struct ieee80211_local *local = sdata->local; struct ieee80211_if_sta *ifsta; if (!req) return -EINVAL; if (local->scan_req && local->scan_req != req) return -EBUSY; local->scan_req = req; if (sdata->vif.type != NL80211_IFTYPE_STATION) return ieee80211_start_scan(sdata, req); /* * STA has a state machine that might need to defer scanning * while it's trying to associate/authenticate, therefore we * queue it up to the state machine in that case. */ if (local->sw_scanning || local->hw_scanning) { if (local->scan_sdata == sdata) return 0; return -EBUSY; } ifsta = &sdata->u.sta; set_bit(IEEE80211_STA_REQ_SCAN, &ifsta->request); queue_work(local->hw.workqueue, &ifsta->work); return 0; }