| /* |
| * Scanning implementation |
| * |
| * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi> |
| * Copyright 2004, Instant802 Networks, Inc. |
| * Copyright 2005, Devicescape Software, Inc. |
| * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz> |
| * Copyright 2007, Michael Wu <flamingice@sourmilk.net> |
| * |
| * 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 */ |
| |
| #include <linux/wireless.h> |
| #include <linux/if_arp.h> |
| #include <linux/rtnetlink.h> |
| #include <net/mac80211.h> |
| #include <net/iw_handler.h> |
| |
| #include "ieee80211_i.h" |
| #include "driver-ops.h" |
| #include "mesh.h" |
| |
| #define IEEE80211_PROBE_DELAY (HZ / 33) |
| #define IEEE80211_CHANNEL_TIME (HZ / 33) |
| #define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 8) |
| |
| struct ieee80211_bss * |
| ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq, |
| u8 *ssid, u8 ssid_len) |
| { |
| return (void *)cfg80211_get_bss(local->hw.wiphy, |
| ieee80211_get_channel(local->hw.wiphy, |
| freq), |
| bssid, ssid, ssid_len, |
| 0, 0); |
| } |
| |
| static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss) |
| { |
| struct ieee80211_bss *bss = (void *)cbss; |
| |
| kfree(bss_mesh_id(bss)); |
| kfree(bss_mesh_cfg(bss)); |
| } |
| |
| void ieee80211_rx_bss_put(struct ieee80211_local *local, |
| struct ieee80211_bss *bss) |
| { |
| cfg80211_put_bss((struct cfg80211_bss *)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; |
| s32 signal = 0; |
| |
| if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) |
| signal = rx_status->signal * 100; |
| else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC) |
| signal = (rx_status->signal * 100) / local->hw.max_signal; |
| |
| bss = (void *)cfg80211_inform_bss_frame(local->hw.wiphy, channel, |
| mgmt, len, signal, GFP_ATOMIC); |
| |
| if (!bss) |
| return NULL; |
| |
| bss->cbss.free_priv = ieee80211_rx_bss_free; |
| |
| /* 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; |
| } |
| |
| 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->wmm_used = elems->wmm_param || elems->wmm_info; |
| |
| if (!beacon) |
| bss->last_probe_resp = jiffies; |
| |
| return bss; |
| } |
| |
| ieee80211_rx_result |
| ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb) |
| { |
| struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb); |
| 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; |
| } |
| |
| /* |
| * inform AP that we will go to sleep so that it will buffer the frames |
| * while we scan |
| */ |
| static void ieee80211_scan_ps_enable(struct ieee80211_sub_if_data *sdata) |
| { |
| struct ieee80211_local *local = sdata->local; |
| bool ps = false; |
| |
| /* FIXME: what to do when local->pspolling is true? */ |
| |
| del_timer_sync(&local->dynamic_ps_timer); |
| cancel_work_sync(&local->dynamic_ps_enable_work); |
| |
| if (local->hw.conf.flags & IEEE80211_CONF_PS) { |
| ps = true; |
| local->hw.conf.flags &= ~IEEE80211_CONF_PS; |
| ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS); |
| } |
| |
| if (!ps || !(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK)) |
| /* |
| * If power save was enabled, no need to send a nullfunc |
| * frame because AP knows that we are sleeping. But if the |
| * hardware is creating the nullfunc frame for power save |
| * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not |
| * enabled) and power save was enabled, the firmware just |
| * sent a null frame with power save disabled. So we need |
| * to send a new nullfunc frame to inform the AP that we |
| * are again sleeping. |
| */ |
| ieee80211_send_nullfunc(local, sdata, 1); |
| } |
| |
| /* inform AP that we are awake again, unless power save is enabled */ |
| static void ieee80211_scan_ps_disable(struct ieee80211_sub_if_data *sdata) |
| { |
| struct ieee80211_local *local = sdata->local; |
| |
| if (!local->ps_sdata) |
| ieee80211_send_nullfunc(local, sdata, 0); |
| else { |
| /* |
| * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware |
| * will send a nullfunc frame with the powersave bit set |
| * even though the AP already knows that we are sleeping. |
| * This could be avoided by sending a null frame with power |
| * save bit disabled before enabling the power save, but |
| * this doesn't gain anything. |
| * |
| * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need |
| * to send a nullfunc frame because AP already knows that |
| * we are sleeping, let's just enable power save mode in |
| * hardware. |
| */ |
| local->hw.conf.flags |= IEEE80211_CONF_PS; |
| ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS); |
| } |
| } |
| |
| static void ieee80211_restore_scan_ies(struct ieee80211_local *local) |
| { |
| kfree(local->scan_req->ie); |
| local->scan_req->ie = local->orig_ies; |
| local->scan_req->ie_len = local->orig_ies_len; |
| } |
| |
| void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) |
| { |
| struct ieee80211_local *local = hw_to_local(hw); |
| struct ieee80211_sub_if_data *sdata; |
| bool was_hw_scan; |
| |
| mutex_lock(&local->scan_mtx); |
| |
| if (WARN_ON(!local->hw_scanning && !local->sw_scanning)) { |
| mutex_unlock(&local->scan_mtx); |
| return; |
| } |
| |
| if (WARN_ON(!local->scan_req)) { |
| mutex_unlock(&local->scan_mtx); |
| return; |
| } |
| |
| if (local->hw_scanning) |
| ieee80211_restore_scan_ies(local); |
| |
| if (local->scan_req != &local->int_scan_req) |
| cfg80211_scan_done(local->scan_req, aborted); |
| local->scan_req = NULL; |
| |
| was_hw_scan = local->hw_scanning; |
| local->hw_scanning = false; |
| local->sw_scanning = false; |
| local->scan_channel = NULL; |
| |
| /* we only have to protect scan_req and hw/sw scan */ |
| mutex_unlock(&local->scan_mtx); |
| |
| ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); |
| if (was_hw_scan) |
| goto done; |
| |
| spin_lock_bh(&local->filter_lock); |
| local->filter_flags &= ~FIF_BCN_PRBRESP_PROMISC; |
| drv_configure_filter(local, FIF_BCN_PRBRESP_PROMISC, |
| &local->filter_flags, |
| local->mc_count, |
| local->mc_list); |
| spin_unlock_bh(&local->filter_lock); |
| |
| drv_sw_scan_complete(local); |
| |
| 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.mgd.associated) { |
| ieee80211_scan_ps_disable(sdata); |
| 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_bss_info_change_notify( |
| sdata, BSS_CHANGED_BEACON_ENABLED); |
| } |
| mutex_unlock(&local->iflist_mtx); |
| |
| done: |
| ieee80211_recalc_idle(local); |
| ieee80211_mlme_notify_scan_completed(local); |
| ieee80211_ibss_notify_scan_completed(local); |
| ieee80211_mesh_notify_scan_completed(local); |
| } |
| EXPORT_SYMBOL(ieee80211_scan_completed); |
| |
| static int ieee80211_start_sw_scan(struct ieee80211_local *local) |
| { |
| struct ieee80211_sub_if_data *sdata; |
| |
| /* |
| * Hardware/driver doesn't support hw_scan, so use software |
| * scanning instead. First send a nullfunc frame with power save |
| * bit on so that AP will buffer the frames for us while we are not |
| * listening, then send probe requests to each channel and wait for |
| * the responses. After all channels are scanned, tune back to the |
| * original channel and send a nullfunc frame with power save bit |
| * off to trigger the AP to send us all the buffered frames. |
| * |
| * Note that while local->sw_scanning is true everything else but |
| * nullfunc frames and probe requests will be dropped in |
| * ieee80211_tx_h_check_assoc(). |
| */ |
| drv_sw_scan_start(local); |
| |
| 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_bss_info_change_notify( |
| sdata, BSS_CHANGED_BEACON_ENABLED); |
| |
| if (sdata->vif.type == NL80211_IFTYPE_STATION) { |
| if (sdata->u.mgd.associated) { |
| netif_tx_stop_all_queues(sdata->dev); |
| ieee80211_scan_ps_enable(sdata); |
| } |
| } else |
| netif_tx_stop_all_queues(sdata->dev); |
| } |
| mutex_unlock(&local->iflist_mtx); |
| |
| local->scan_state = SCAN_SET_CHANNEL; |
| local->scan_channel_idx = 0; |
| |
| spin_lock_bh(&local->filter_lock); |
| local->filter_flags |= FIF_BCN_PRBRESP_PROMISC; |
| drv_configure_filter(local, FIF_BCN_PRBRESP_PROMISC, |
| &local->filter_flags, |
| local->mc_count, |
| local->mc_list); |
| spin_unlock_bh(&local->filter_lock); |
| |
| /* 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; |
| } |
| |
| |
| static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, |
| struct cfg80211_scan_request *req) |
| { |
| struct ieee80211_local *local = sdata->local; |
| struct ieee80211_if_managed *ifmgd = &sdata->u.mgd; |
| int rc; |
| |
| if (local->scan_req) |
| return -EBUSY; |
| |
| if (local->ops->hw_scan) { |
| u8 *ies; |
| int ielen; |
| |
| ies = kmalloc(2 + IEEE80211_MAX_SSID_LEN + |
| local->scan_ies_len + req->ie_len, GFP_KERNEL); |
| if (!ies) |
| return -ENOMEM; |
| |
| ielen = ieee80211_build_preq_ies(local, ies, |
| req->ie, req->ie_len); |
| local->orig_ies = req->ie; |
| local->orig_ies_len = req->ie_len; |
| req->ie = ies; |
| req->ie_len = ielen; |
| } |
| |
| local->scan_req = req; |
| local->scan_sdata = sdata; |
| |
| if (req != &local->int_scan_req && |
| sdata->vif.type == NL80211_IFTYPE_STATION && |
| !list_empty(&ifmgd->work_list)) { |
| /* actually wait for the work it's doing to finish/time out */ |
| set_bit(IEEE80211_STA_REQ_SCAN, &ifmgd->request); |
| return 0; |
| } |
| |
| if (local->ops->hw_scan) |
| local->hw_scanning = true; |
| else |
| local->sw_scanning = true; |
| /* |
| * Kicking off the scan need not be protected, |
| * only the scan variable stuff, since now |
| * local->scan_req is assigned and other callers |
| * will abort their scan attempts. |
| * |
| * This avoids getting a scan_mtx -> iflist_mtx |
| * dependency, so that the scan completed calls |
| * have more locking freedom. |
| */ |
| |
| ieee80211_recalc_idle(local); |
| mutex_unlock(&local->scan_mtx); |
| |
| if (local->ops->hw_scan) |
| rc = drv_hw_scan(local, local->scan_req); |
| else |
| rc = ieee80211_start_sw_scan(local); |
| |
| mutex_lock(&local->scan_mtx); |
| |
| if (rc) { |
| if (local->ops->hw_scan) { |
| local->hw_scanning = false; |
| ieee80211_restore_scan_ies(local); |
| } else |
| local->sw_scanning = false; |
| |
| ieee80211_recalc_idle(local); |
| |
| local->scan_req = NULL; |
| local->scan_sdata = NULL; |
| } |
| |
| return rc; |
| } |
| |
| 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; |
| |
| mutex_lock(&local->scan_mtx); |
| if (!sdata || !local->scan_req) { |
| mutex_unlock(&local->scan_mtx); |
| return; |
| } |
| |
| if (local->scan_req && !(local->sw_scanning || local->hw_scanning)) { |
| struct cfg80211_scan_request *req = local->scan_req; |
| int rc; |
| |
| local->scan_req = NULL; |
| |
| rc = __ieee80211_start_scan(sdata, req); |
| mutex_unlock(&local->scan_mtx); |
| |
| if (rc) |
| ieee80211_scan_completed(&local->hw, true); |
| return; |
| } |
| |
| mutex_unlock(&local->scan_mtx); |
| |
| /* |
| * Avoid re-scheduling when the sdata is going away. |
| */ |
| if (!netif_running(sdata->dev)) { |
| ieee80211_scan_completed(&local->hw, true); |
| 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->hw, 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; |
| |
| /* |
| * Probe delay is used to update the NAV, cf. 11.1.3.2.2 |
| * (which unfortunately doesn't say _why_ step a) is done, |
| * but it waits for the probe delay or until a frame is |
| * received - and the received frame would update the NAV). |
| * For now, we do not support waiting until a frame is |
| * received. |
| * |
| * In any case, it is not necessary for a passive scan. |
| */ |
| if (chan->flags & IEEE80211_CHAN_PASSIVE_SCAN || |
| !local->scan_req->n_ssids) { |
| next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; |
| break; |
| } |
| |
| next_delay = IEEE80211_PROBE_DELAY; |
| local->scan_state = SCAN_SEND_PROBE; |
| break; |
| case SCAN_SEND_PROBE: |
| 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, |
| local->scan_req->ie, local->scan_req->ie_len); |
| |
| /* |
| * After sending probe requests, wait for probe responses |
| * on the channel. |
| */ |
| next_delay = IEEE80211_CHANNEL_TIME; |
| local->scan_state = SCAN_SET_CHANNEL; |
| break; |
| } |
| |
| queue_delayed_work(local->hw.workqueue, &local->scan_work, |
| next_delay); |
| } |
| |
| int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, |
| struct cfg80211_scan_request *req) |
| { |
| int res; |
| |
| mutex_lock(&sdata->local->scan_mtx); |
| res = __ieee80211_start_scan(sdata, req); |
| mutex_unlock(&sdata->local->scan_mtx); |
| |
| return res; |
| } |
| |
| int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata, |
| const u8 *ssid, u8 ssid_len) |
| { |
| struct ieee80211_local *local = sdata->local; |
| int ret = -EBUSY; |
| |
| mutex_lock(&local->scan_mtx); |
| |
| /* busy scanning */ |
| if (local->scan_req) |
| goto unlock; |
| |
| memcpy(local->int_scan_req.ssids[0].ssid, ssid, IEEE80211_MAX_SSID_LEN); |
| local->int_scan_req.ssids[0].ssid_len = ssid_len; |
| |
| ret = __ieee80211_start_scan(sdata, &sdata->local->int_scan_req); |
| unlock: |
| mutex_unlock(&local->scan_mtx); |
| return ret; |
| } |
| |
| void ieee80211_scan_cancel(struct ieee80211_local *local) |
| { |
| bool swscan; |
| |
| cancel_delayed_work_sync(&local->scan_work); |
| |
| /* |
| * Only call this function when a scan can't be |
| * queued -- mostly at suspend under RTNL. |
| */ |
| mutex_lock(&local->scan_mtx); |
| swscan = local->sw_scanning; |
| mutex_unlock(&local->scan_mtx); |
| |
| if (swscan) |
| ieee80211_scan_completed(&local->hw, true); |
| } |