diff options
Diffstat (limited to 'net/mac80211/scan.c')
| -rw-r--r-- | net/mac80211/scan.c | 1355 |
1 files changed, 1355 insertions, 0 deletions
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c new file mode 100644 index 000000000..de42bcfed --- /dev/null +++ b/net/mac80211/scan.c @@ -0,0 +1,1355 @@ +/* + * 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> + * Copyright 2013-2015 Intel Mobile Communications GmbH + * Copyright 2016-2017 Intel Deutschland GmbH + * + * 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. + */ + +#include <linux/if_arp.h> +#include <linux/etherdevice.h> +#include <linux/rtnetlink.h> +#include <net/sch_generic.h> +#include <linux/slab.h> +#include <linux/export.h> +#include <linux/random.h> +#include <net/mac80211.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 / 9) + +void ieee80211_rx_bss_put(struct ieee80211_local *local, + struct ieee80211_bss *bss) +{ + if (!bss) + return; + cfg80211_put_bss(local->hw.wiphy, + container_of((void *)bss, struct cfg80211_bss, priv)); +} + +static bool is_uapsd_supported(struct ieee802_11_elems *elems) +{ + u8 qos_info; + + if (elems->wmm_info && elems->wmm_info_len == 7 + && elems->wmm_info[5] == 1) + qos_info = elems->wmm_info[6]; + else if (elems->wmm_param && elems->wmm_param_len == 24 + && elems->wmm_param[5] == 1) + qos_info = elems->wmm_param[6]; + else + /* no valid wmm information or parameter element found */ + return false; + + return qos_info & IEEE80211_WMM_IE_AP_QOSINFO_UAPSD; +} + +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 = ieee80211_is_beacon(mgmt->frame_control); + struct cfg80211_bss *cbss; + struct ieee80211_bss *bss; + int clen, srlen; + struct cfg80211_inform_bss bss_meta = { + .boottime_ns = rx_status->boottime_ns, + }; + bool signal_valid; + struct ieee80211_sub_if_data *scan_sdata; + + if (rx_status->flag & RX_FLAG_NO_SIGNAL_VAL) + bss_meta.signal = 0; /* invalid signal indication */ + else if (ieee80211_hw_check(&local->hw, SIGNAL_DBM)) + bss_meta.signal = rx_status->signal * 100; + else if (ieee80211_hw_check(&local->hw, SIGNAL_UNSPEC)) + bss_meta.signal = (rx_status->signal * 100) / local->hw.max_signal; + + bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_20; + if (rx_status->bw == RATE_INFO_BW_5) + bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_5; + else if (rx_status->bw == RATE_INFO_BW_10) + bss_meta.scan_width = NL80211_BSS_CHAN_WIDTH_10; + + bss_meta.chan = channel; + + rcu_read_lock(); + scan_sdata = rcu_dereference(local->scan_sdata); + if (scan_sdata && scan_sdata->vif.type == NL80211_IFTYPE_STATION && + scan_sdata->vif.bss_conf.assoc && + ieee80211_have_rx_timestamp(rx_status)) { + bss_meta.parent_tsf = + ieee80211_calculate_rx_timestamp(local, rx_status, + len + FCS_LEN, 24); + ether_addr_copy(bss_meta.parent_bssid, + scan_sdata->vif.bss_conf.bssid); + } + rcu_read_unlock(); + + cbss = cfg80211_inform_bss_frame_data(local->hw.wiphy, &bss_meta, + mgmt, len, GFP_ATOMIC); + if (!cbss) + return NULL; + /* In case the signal is invalid update the status */ + signal_valid = abs(channel->center_freq - cbss->channel->center_freq) + <= local->hw.wiphy->max_adj_channel_rssi_comp; + if (!signal_valid) + rx_status->flag |= RX_FLAG_NO_SIGNAL_VAL; + + bss = (void *)cbss->priv; + + if (beacon) + bss->device_ts_beacon = rx_status->device_timestamp; + else + bss->device_ts_presp = rx_status->device_timestamp; + + if (elems->parse_error) { + if (beacon) + bss->corrupt_data |= IEEE80211_BSS_CORRUPT_BEACON; + else + bss->corrupt_data |= IEEE80211_BSS_CORRUPT_PROBE_RESP; + } else { + if (beacon) + bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_BEACON; + else + bss->corrupt_data &= ~IEEE80211_BSS_CORRUPT_PROBE_RESP; + } + + /* save the ERP value so that it is available at association time */ + if (elems->erp_info && (!elems->parse_error || + !(bss->valid_data & IEEE80211_BSS_VALID_ERP))) { + bss->erp_value = elems->erp_info[0]; + bss->has_erp_value = true; + if (!elems->parse_error) + bss->valid_data |= IEEE80211_BSS_VALID_ERP; + } + + /* replace old supported rates if we get new values */ + if (!elems->parse_error || + !(bss->valid_data & IEEE80211_BSS_VALID_RATES)) { + srlen = 0; + if (elems->supp_rates) { + clen = IEEE80211_MAX_SUPP_RATES; + if (clen > elems->supp_rates_len) + clen = elems->supp_rates_len; + memcpy(bss->supp_rates, elems->supp_rates, clen); + srlen += clen; + } + if (elems->ext_supp_rates) { + clen = IEEE80211_MAX_SUPP_RATES - srlen; + if (clen > elems->ext_supp_rates_len) + clen = elems->ext_supp_rates_len; + memcpy(bss->supp_rates + srlen, elems->ext_supp_rates, + clen); + srlen += clen; + } + if (srlen) { + bss->supp_rates_len = srlen; + if (!elems->parse_error) + bss->valid_data |= IEEE80211_BSS_VALID_RATES; + } + } + + if (!elems->parse_error || + !(bss->valid_data & IEEE80211_BSS_VALID_WMM)) { + bss->wmm_used = elems->wmm_param || elems->wmm_info; + bss->uapsd_supported = is_uapsd_supported(elems); + if (!elems->parse_error) + bss->valid_data |= IEEE80211_BSS_VALID_WMM; + } + + if (beacon) { + struct ieee80211_supported_band *sband = + local->hw.wiphy->bands[rx_status->band]; + if (!(rx_status->encoding == RX_ENC_HT) && + !(rx_status->encoding == RX_ENC_VHT)) + bss->beacon_rate = + &sband->bitrates[rx_status->rate_idx]; + } + + return bss; +} + +static bool ieee80211_scan_accept_presp(struct ieee80211_sub_if_data *sdata, + u32 scan_flags, const u8 *da) +{ + if (!sdata) + return false; + /* accept broadcast for OCE */ + if (scan_flags & NL80211_SCAN_FLAG_ACCEPT_BCAST_PROBE_RESP && + is_broadcast_ether_addr(da)) + return true; + if (scan_flags & NL80211_SCAN_FLAG_RANDOM_ADDR) + return true; + return ether_addr_equal(da, sdata->vif.addr); +} + +void ieee80211_scan_rx(struct ieee80211_local *local, struct sk_buff *skb) +{ + struct ieee80211_rx_status *rx_status = IEEE80211_SKB_RXCB(skb); + struct ieee80211_sub_if_data *sdata1, *sdata2; + struct ieee80211_mgmt *mgmt = (void *)skb->data; + struct ieee80211_bss *bss; + u8 *elements; + struct ieee80211_channel *channel; + size_t baselen; + struct ieee802_11_elems elems; + + if (skb->len < 24 || + (!ieee80211_is_probe_resp(mgmt->frame_control) && + !ieee80211_is_beacon(mgmt->frame_control))) + return; + + sdata1 = rcu_dereference(local->scan_sdata); + sdata2 = rcu_dereference(local->sched_scan_sdata); + + if (likely(!sdata1 && !sdata2)) + return; + + if (test_and_clear_bit(SCAN_BEACON_WAIT, &local->scanning)) { + /* + * we were passive scanning because of radar/no-IR, but + * the beacon/proberesp rx gives us an opportunity to upgrade + * to active scan + */ + set_bit(SCAN_BEACON_DONE, &local->scanning); + ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0); + } + + if (ieee80211_is_probe_resp(mgmt->frame_control)) { + struct cfg80211_scan_request *scan_req; + struct cfg80211_sched_scan_request *sched_scan_req; + u32 scan_req_flags = 0, sched_scan_req_flags = 0; + + scan_req = rcu_dereference(local->scan_req); + sched_scan_req = rcu_dereference(local->sched_scan_req); + + if (scan_req) + scan_req_flags = scan_req->flags; + + if (sched_scan_req) + sched_scan_req_flags = sched_scan_req->flags; + + /* ignore ProbeResp to foreign address or non-bcast (OCE) + * unless scanning with randomised address + */ + if (!ieee80211_scan_accept_presp(sdata1, scan_req_flags, + mgmt->da) && + !ieee80211_scan_accept_presp(sdata2, sched_scan_req_flags, + mgmt->da)) + return; + + elements = mgmt->u.probe_resp.variable; + baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable); + } else { + baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable); + elements = mgmt->u.beacon.variable; + } + + if (baselen > skb->len) + return; + + ieee802_11_parse_elems(elements, skb->len - baselen, false, &elems); + + channel = ieee80211_get_channel(local->hw.wiphy, rx_status->freq); + + if (!channel || channel->flags & IEEE80211_CHAN_DISABLED) + return; + + bss = ieee80211_bss_info_update(local, rx_status, + mgmt, skb->len, &elems, + channel); + if (bss) + ieee80211_rx_bss_put(local, bss); +} + +static void +ieee80211_prepare_scan_chandef(struct cfg80211_chan_def *chandef, + enum nl80211_bss_scan_width scan_width) +{ + memset(chandef, 0, sizeof(*chandef)); + switch (scan_width) { + case NL80211_BSS_CHAN_WIDTH_5: + chandef->width = NL80211_CHAN_WIDTH_5; + break; + case NL80211_BSS_CHAN_WIDTH_10: + chandef->width = NL80211_CHAN_WIDTH_10; + break; + default: + chandef->width = NL80211_CHAN_WIDTH_20_NOHT; + break; + } +} + +/* return false if no more work */ +static bool ieee80211_prep_hw_scan(struct ieee80211_local *local) +{ + struct cfg80211_scan_request *req; + struct cfg80211_chan_def chandef; + u8 bands_used = 0; + int i, ielen, n_chans; + u32 flags = 0; + + req = rcu_dereference_protected(local->scan_req, + lockdep_is_held(&local->mtx)); + + if (test_bit(SCAN_HW_CANCELLED, &local->scanning)) + return false; + + if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) { + for (i = 0; i < req->n_channels; i++) { + local->hw_scan_req->req.channels[i] = req->channels[i]; + bands_used |= BIT(req->channels[i]->band); + } + + n_chans = req->n_channels; + } else { + do { + if (local->hw_scan_band == NUM_NL80211_BANDS) + return false; + + n_chans = 0; + + for (i = 0; i < req->n_channels; i++) { + if (req->channels[i]->band != + local->hw_scan_band) + continue; + local->hw_scan_req->req.channels[n_chans] = + req->channels[i]; + n_chans++; + bands_used |= BIT(req->channels[i]->band); + } + + local->hw_scan_band++; + } while (!n_chans); + } + + local->hw_scan_req->req.n_channels = n_chans; + ieee80211_prepare_scan_chandef(&chandef, req->scan_width); + + if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT) + flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT; + + ielen = ieee80211_build_preq_ies(local, + (u8 *)local->hw_scan_req->req.ie, + local->hw_scan_ies_bufsize, + &local->hw_scan_req->ies, + req->ie, req->ie_len, + bands_used, req->rates, &chandef, + flags); + local->hw_scan_req->req.ie_len = ielen; + local->hw_scan_req->req.no_cck = req->no_cck; + ether_addr_copy(local->hw_scan_req->req.mac_addr, req->mac_addr); + ether_addr_copy(local->hw_scan_req->req.mac_addr_mask, + req->mac_addr_mask); + ether_addr_copy(local->hw_scan_req->req.bssid, req->bssid); + + return true; +} + +static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted) +{ + struct ieee80211_local *local = hw_to_local(hw); + bool hw_scan = local->ops->hw_scan; + bool was_scanning = local->scanning; + struct cfg80211_scan_request *scan_req; + struct ieee80211_sub_if_data *scan_sdata; + struct ieee80211_sub_if_data *sdata; + + lockdep_assert_held(&local->mtx); + + /* + * It's ok to abort a not-yet-running scan (that + * we have one at all will be verified by checking + * local->scan_req next), but not to complete it + * successfully. + */ + if (WARN_ON(!local->scanning && !aborted)) + aborted = true; + + if (WARN_ON(!local->scan_req)) + return; + + if (hw_scan && !aborted && + !ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS) && + ieee80211_prep_hw_scan(local)) { + int rc; + + rc = drv_hw_scan(local, + rcu_dereference_protected(local->scan_sdata, + lockdep_is_held(&local->mtx)), + local->hw_scan_req); + + if (rc == 0) + return; + + /* HW scan failed and is going to be reported as aborted, + * so clear old scan info. + */ + memset(&local->scan_info, 0, sizeof(local->scan_info)); + aborted = true; + } + + kfree(local->hw_scan_req); + local->hw_scan_req = NULL; + + scan_req = rcu_dereference_protected(local->scan_req, + lockdep_is_held(&local->mtx)); + + if (scan_req != local->int_scan_req) { + local->scan_info.aborted = aborted; + cfg80211_scan_done(scan_req, &local->scan_info); + } + RCU_INIT_POINTER(local->scan_req, NULL); + + scan_sdata = rcu_dereference_protected(local->scan_sdata, + lockdep_is_held(&local->mtx)); + RCU_INIT_POINTER(local->scan_sdata, NULL); + + local->scanning = 0; + local->scan_chandef.chan = NULL; + + /* Set power back to normal operating levels. */ + ieee80211_hw_config(local, 0); + + if (!hw_scan) { + ieee80211_configure_filter(local); + drv_sw_scan_complete(local, scan_sdata); + ieee80211_offchannel_return(local); + } + + ieee80211_recalc_idle(local); + + ieee80211_mlme_notify_scan_completed(local); + ieee80211_ibss_notify_scan_completed(local); + + /* Requeue all the work that might have been ignored while + * the scan was in progress; if there was none this will + * just be a no-op for the particular interface. + */ + list_for_each_entry_rcu(sdata, &local->interfaces, list) { + if (ieee80211_sdata_running(sdata)) + ieee80211_queue_work(&sdata->local->hw, &sdata->work); + } + + if (was_scanning) + ieee80211_start_next_roc(local); +} + +void ieee80211_scan_completed(struct ieee80211_hw *hw, + struct cfg80211_scan_info *info) +{ + struct ieee80211_local *local = hw_to_local(hw); + + trace_api_scan_completed(local, info->aborted); + + set_bit(SCAN_COMPLETED, &local->scanning); + if (info->aborted) + set_bit(SCAN_ABORTED, &local->scanning); + + memcpy(&local->scan_info, info, sizeof(*info)); + + ieee80211_queue_delayed_work(&local->hw, &local->scan_work, 0); +} +EXPORT_SYMBOL(ieee80211_scan_completed); + +static int ieee80211_start_sw_scan(struct ieee80211_local *local, + struct ieee80211_sub_if_data *sdata) +{ + /* Software scan is not supported in multi-channel cases */ + if (local->use_chanctx) + return -EOPNOTSUPP; + + /* + * 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, sdata, local->scan_addr); + + local->leave_oper_channel_time = jiffies; + local->next_scan_state = SCAN_DECISION; + local->scan_channel_idx = 0; + + ieee80211_offchannel_stop_vifs(local); + + /* ensure nullfunc is transmitted before leaving operating channel */ + ieee80211_flush_queues(local, NULL, false); + + ieee80211_configure_filter(local); + + /* We need to set power level at maximum rate for scanning. */ + ieee80211_hw_config(local, 0); + + ieee80211_queue_delayed_work(&local->hw, + &local->scan_work, 0); + + return 0; +} + +static bool ieee80211_can_scan(struct ieee80211_local *local, + struct ieee80211_sub_if_data *sdata) +{ + if (ieee80211_is_radar_required(local)) + return false; + + if (!list_empty(&local->roc_list)) + return false; + + if (sdata->vif.type == NL80211_IFTYPE_STATION && + sdata->u.mgd.flags & IEEE80211_STA_CONNECTION_POLL) + return false; + + return true; +} + +void ieee80211_run_deferred_scan(struct ieee80211_local *local) +{ + lockdep_assert_held(&local->mtx); + + if (!local->scan_req || local->scanning) + return; + + if (!ieee80211_can_scan(local, + rcu_dereference_protected( + local->scan_sdata, + lockdep_is_held(&local->mtx)))) + return; + + ieee80211_queue_delayed_work(&local->hw, &local->scan_work, + round_jiffies_relative(0)); +} + +static void ieee80211_send_scan_probe_req(struct ieee80211_sub_if_data *sdata, + const u8 *src, const u8 *dst, + const u8 *ssid, size_t ssid_len, + const u8 *ie, size_t ie_len, + u32 ratemask, u32 flags, u32 tx_flags, + struct ieee80211_channel *channel) +{ + struct sk_buff *skb; + u32 txdata_flags = 0; + + skb = ieee80211_build_probe_req(sdata, src, dst, ratemask, channel, + ssid, ssid_len, + ie, ie_len, flags); + + if (skb) { + if (flags & IEEE80211_PROBE_FLAG_RANDOM_SN) { + struct ieee80211_hdr *hdr = (void *)skb->data; + u16 sn = get_random_u32(); + + txdata_flags |= IEEE80211_TX_NO_SEQNO; + hdr->seq_ctrl = + cpu_to_le16(IEEE80211_SN_TO_SEQ(sn)); + } + IEEE80211_SKB_CB(skb)->flags |= tx_flags; + ieee80211_tx_skb_tid_band(sdata, skb, 7, channel->band, + txdata_flags); + } +} + +static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, + unsigned long *next_delay) +{ + int i; + struct ieee80211_sub_if_data *sdata; + struct cfg80211_scan_request *scan_req; + enum nl80211_band band = local->hw.conf.chandef.chan->band; + u32 flags = 0, tx_flags; + + scan_req = rcu_dereference_protected(local->scan_req, + lockdep_is_held(&local->mtx)); + + tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK; + if (scan_req->no_cck) + tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE; + if (scan_req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT) + flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT; + if (scan_req->flags & NL80211_SCAN_FLAG_RANDOM_SN) + flags |= IEEE80211_PROBE_FLAG_RANDOM_SN; + + sdata = rcu_dereference_protected(local->scan_sdata, + lockdep_is_held(&local->mtx)); + + for (i = 0; i < scan_req->n_ssids; i++) + ieee80211_send_scan_probe_req( + sdata, local->scan_addr, scan_req->bssid, + scan_req->ssids[i].ssid, scan_req->ssids[i].ssid_len, + scan_req->ie, scan_req->ie_len, + scan_req->rates[band], flags, + tx_flags, local->hw.conf.chandef.chan); + + /* + * After sending probe requests, wait for probe responses + * on the channel. + */ + *next_delay = IEEE80211_CHANNEL_TIME; + local->next_scan_state = SCAN_DECISION; +} + +static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, + struct cfg80211_scan_request *req) +{ + struct ieee80211_local *local = sdata->local; + int rc; + + lockdep_assert_held(&local->mtx); + + if (local->scan_req || ieee80211_is_radar_required(local)) + return -EBUSY; + + if (!ieee80211_can_scan(local, sdata)) { + /* wait for the work to finish/time out */ + rcu_assign_pointer(local->scan_req, req); + rcu_assign_pointer(local->scan_sdata, sdata); + return 0; + } + + if (local->ops->hw_scan) { + u8 *ies; + + local->hw_scan_ies_bufsize = local->scan_ies_len + req->ie_len; + + if (ieee80211_hw_check(&local->hw, SINGLE_SCAN_ON_ALL_BANDS)) { + int i, n_bands = 0; + u8 bands_counted = 0; + + for (i = 0; i < req->n_channels; i++) { + if (bands_counted & BIT(req->channels[i]->band)) + continue; + bands_counted |= BIT(req->channels[i]->band); + n_bands++; + } + + local->hw_scan_ies_bufsize *= n_bands; + } + + local->hw_scan_req = kmalloc( + sizeof(*local->hw_scan_req) + + req->n_channels * sizeof(req->channels[0]) + + local->hw_scan_ies_bufsize, GFP_KERNEL); + if (!local->hw_scan_req) + return -ENOMEM; + + local->hw_scan_req->req.ssids = req->ssids; + local->hw_scan_req->req.n_ssids = req->n_ssids; + ies = (u8 *)local->hw_scan_req + + sizeof(*local->hw_scan_req) + + req->n_channels * sizeof(req->channels[0]); + local->hw_scan_req->req.ie = ies; + local->hw_scan_req->req.flags = req->flags; + eth_broadcast_addr(local->hw_scan_req->req.bssid); + local->hw_scan_req->req.duration = req->duration; + local->hw_scan_req->req.duration_mandatory = + req->duration_mandatory; + + local->hw_scan_band = 0; + + /* + * After allocating local->hw_scan_req, we must + * go through until ieee80211_prep_hw_scan(), so + * anything that might be changed here and leave + * this function early must not go after this + * allocation. + */ + } + + rcu_assign_pointer(local->scan_req, req); + rcu_assign_pointer(local->scan_sdata, sdata); + + if (req->flags & NL80211_SCAN_FLAG_RANDOM_ADDR) + get_random_mask_addr(local->scan_addr, + req->mac_addr, + req->mac_addr_mask); + else + memcpy(local->scan_addr, sdata->vif.addr, ETH_ALEN); + + if (local->ops->hw_scan) { + __set_bit(SCAN_HW_SCANNING, &local->scanning); + } else if ((req->n_channels == 1) && + (req->channels[0] == local->_oper_chandef.chan)) { + /* + * If we are scanning only on the operating channel + * then we do not need to stop normal activities + */ + unsigned long next_delay; + + __set_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning); + + ieee80211_recalc_idle(local); + + /* Notify driver scan is starting, keep order of operations + * same as normal software scan, in case that matters. */ + drv_sw_scan_start(local, sdata, local->scan_addr); + + ieee80211_configure_filter(local); /* accept probe-responses */ + + /* We need to ensure power level is at max for scanning. */ + ieee80211_hw_config(local, 0); + + if ((req->channels[0]->flags & (IEEE80211_CHAN_NO_IR | + IEEE80211_CHAN_RADAR)) || + !req->n_ssids) { + next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; + if (req->n_ssids) + set_bit(SCAN_BEACON_WAIT, &local->scanning); + } else { + ieee80211_scan_state_send_probe(local, &next_delay); + next_delay = IEEE80211_CHANNEL_TIME; + } + + /* Now, just wait a bit and we are all done! */ + ieee80211_queue_delayed_work(&local->hw, &local->scan_work, + next_delay); + return 0; + } else { + /* Do normal software scan */ + __set_bit(SCAN_SW_SCANNING, &local->scanning); + } + + ieee80211_recalc_idle(local); + + if (local->ops->hw_scan) { + WARN_ON(!ieee80211_prep_hw_scan(local)); + rc = drv_hw_scan(local, sdata, local->hw_scan_req); + } else { + rc = ieee80211_start_sw_scan(local, sdata); + } + + if (rc) { + kfree(local->hw_scan_req); + local->hw_scan_req = NULL; + local->scanning = 0; + + ieee80211_recalc_idle(local); + + local->scan_req = NULL; + RCU_INIT_POINTER(local->scan_sdata, NULL); + } + + return rc; +} + +static unsigned long +ieee80211_scan_get_channel_time(struct ieee80211_channel *chan) +{ + /* + * TODO: channel switching also consumes quite some time, + * add that delay as well to get a better estimation + */ + if (chan->flags & (IEEE80211_CHAN_NO_IR | IEEE80211_CHAN_RADAR)) + return IEEE80211_PASSIVE_CHANNEL_TIME; + return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME; +} + +static void ieee80211_scan_state_decision(struct ieee80211_local *local, + unsigned long *next_delay) +{ + bool associated = false; + bool tx_empty = true; + bool bad_latency; + struct ieee80211_sub_if_data *sdata; + struct ieee80211_channel *next_chan; + enum mac80211_scan_state next_scan_state; + struct cfg80211_scan_request *scan_req; + + /* + * check if at least one STA interface is associated, + * check if at least one STA interface has pending tx frames + * and grab the lowest used beacon interval + */ + mutex_lock(&local->iflist_mtx); + list_for_each_entry(sdata, &local->interfaces, list) { + if (!ieee80211_sdata_running(sdata)) + continue; + + if (sdata->vif.type == NL80211_IFTYPE_STATION) { + if (sdata->u.mgd.associated) { + associated = true; + + if (!qdisc_all_tx_empty(sdata->dev)) { + tx_empty = false; + break; + } + } + } + } + mutex_unlock(&local->iflist_mtx); + + scan_req = rcu_dereference_protected(local->scan_req, + lockdep_is_held(&local->mtx)); + + next_chan = scan_req->channels[local->scan_channel_idx]; + + /* + * we're currently scanning a different channel, let's + * see if we can scan another channel without interfering + * with the current traffic situation. + * + * Keep good latency, do not stay off-channel more than 125 ms. + */ + + bad_latency = time_after(jiffies + + ieee80211_scan_get_channel_time(next_chan), + local->leave_oper_channel_time + HZ / 8); + + if (associated && !tx_empty) { + if (scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) + next_scan_state = SCAN_ABORT; + else + next_scan_state = SCAN_SUSPEND; + } else if (associated && bad_latency) { + next_scan_state = SCAN_SUSPEND; + } else { + next_scan_state = SCAN_SET_CHANNEL; + } + + local->next_scan_state = next_scan_state; + + *next_delay = 0; +} + +static void ieee80211_scan_state_set_channel(struct ieee80211_local *local, + unsigned long *next_delay) +{ + int skip; + struct ieee80211_channel *chan; + enum nl80211_bss_scan_width oper_scan_width; + struct cfg80211_scan_request *scan_req; + + scan_req = rcu_dereference_protected(local->scan_req, + lockdep_is_held(&local->mtx)); + + skip = 0; + chan = scan_req->channels[local->scan_channel_idx]; + + local->scan_chandef.chan = chan; + local->scan_chandef.center_freq1 = chan->center_freq; + local->scan_chandef.center_freq2 = 0; + switch (scan_req->scan_width) { + case NL80211_BSS_CHAN_WIDTH_5: + local->scan_chandef.width = NL80211_CHAN_WIDTH_5; + break; + case NL80211_BSS_CHAN_WIDTH_10: + local->scan_chandef.width = NL80211_CHAN_WIDTH_10; + break; + case NL80211_BSS_CHAN_WIDTH_20: + /* If scanning on oper channel, use whatever channel-type + * is currently in use. + */ + oper_scan_width = cfg80211_chandef_to_scan_width( + &local->_oper_chandef); + if (chan == local->_oper_chandef.chan && + oper_scan_width == scan_req->scan_width) + local->scan_chandef = local->_oper_chandef; + else + local->scan_chandef.width = NL80211_CHAN_WIDTH_20_NOHT; + break; + } + + if (ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL)) + skip = 1; + + /* advance state machine to next channel/band */ + local->scan_channel_idx++; + + if (skip) { + /* if we skip this channel return to the decision state */ + local->next_scan_state = SCAN_DECISION; + return; + } + + /* + * 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_NO_IR | IEEE80211_CHAN_RADAR)) || + !scan_req->n_ssids) { + *next_delay = IEEE80211_PASSIVE_CHANNEL_TIME; + local->next_scan_state = SCAN_DECISION; + if (scan_req->n_ssids) + set_bit(SCAN_BEACON_WAIT, &local->scanning); + return; + } + + /* active scan, send probes */ + *next_delay = IEEE80211_PROBE_DELAY; + local->next_scan_state = SCAN_SEND_PROBE; +} + +static void ieee80211_scan_state_suspend(struct ieee80211_local *local, + unsigned long *next_delay) +{ + /* switch back to the operating channel */ + local->scan_chandef.chan = NULL; + ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL); + + /* disable PS */ + ieee80211_offchannel_return(local); + + *next_delay = HZ / 5; + /* afterwards, resume scan & go to next channel */ + local->next_scan_state = SCAN_RESUME; +} + +static void ieee80211_scan_state_resume(struct ieee80211_local *local, + unsigned long *next_delay) +{ + ieee80211_offchannel_stop_vifs(local); + + if (local->ops->flush) { + ieee80211_flush_queues(local, NULL, false); + *next_delay = 0; + } else + *next_delay = HZ / 10; + + /* remember when we left the operating channel */ + local->leave_oper_channel_time = jiffies; + + /* advance to the next channel to be scanned */ + local->next_scan_state = SCAN_SET_CHANNEL; +} + +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; + struct cfg80211_scan_request *scan_req; + unsigned long next_delay = 0; + bool aborted; + + mutex_lock(&local->mtx); + + if (!ieee80211_can_run_worker(local)) { + aborted = true; + goto out_complete; + } + + sdata = rcu_dereference_protected(local->scan_sdata, + lockdep_is_held(&local->mtx)); + scan_req = rcu_dereference_protected(local->scan_req, + lockdep_is_held(&local->mtx)); + + /* When scanning on-channel, the first-callback means completed. */ + if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) { + aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); + goto out_complete; + } + + if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) { + aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning); + goto out_complete; + } + + if (!sdata || !scan_req) + goto out; + + if (!local->scanning) { + int rc; + + RCU_INIT_POINTER(local->scan_req, NULL); + RCU_INIT_POINTER(local->scan_sdata, NULL); + + rc = __ieee80211_start_scan(sdata, scan_req); + if (rc) { + /* need to complete scan in cfg80211 */ + rcu_assign_pointer(local->scan_req, scan_req); + aborted = true; + goto out_complete; + } else + goto out; + } + + clear_bit(SCAN_BEACON_WAIT, &local->scanning); + + /* + * as long as no delay is required advance immediately + * without scheduling a new work + */ + do { + if (!ieee80211_sdata_running(sdata)) { + aborted = true; + goto out_complete; + } + + if (test_and_clear_bit(SCAN_BEACON_DONE, &local->scanning) && + local->next_scan_state == SCAN_DECISION) + local->next_scan_state = SCAN_SEND_PROBE; + + switch (local->next_scan_state) { + case SCAN_DECISION: + /* if no more bands/channels left, complete scan */ + if (local->scan_channel_idx >= scan_req->n_channels) { + aborted = false; + goto out_complete; + } + ieee80211_scan_state_decision(local, &next_delay); + break; + case SCAN_SET_CHANNEL: + ieee80211_scan_state_set_channel(local, &next_delay); + break; + case SCAN_SEND_PROBE: + ieee80211_scan_state_send_probe(local, &next_delay); + break; + case SCAN_SUSPEND: + ieee80211_scan_state_suspend(local, &next_delay); + break; + case SCAN_RESUME: + ieee80211_scan_state_resume(local, &next_delay); + break; + case SCAN_ABORT: + aborted = true; + goto out_complete; + } + } while (next_delay == 0); + + ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay); + goto out; + +out_complete: + __ieee80211_scan_completed(&local->hw, aborted); +out: + mutex_unlock(&local->mtx); +} + +int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata, + struct cfg80211_scan_request *req) +{ + int res; + + mutex_lock(&sdata->local->mtx); + res = __ieee80211_start_scan(sdata, req); + mutex_unlock(&sdata->local->mtx); + + return res; +} + +int ieee80211_request_ibss_scan(struct ieee80211_sub_if_data *sdata, + const u8 *ssid, u8 ssid_len, + struct ieee80211_channel **channels, + unsigned int n_channels, + enum nl80211_bss_scan_width scan_width) +{ + struct ieee80211_local *local = sdata->local; + int ret = -EBUSY, i, n_ch = 0; + enum nl80211_band band; + + mutex_lock(&local->mtx); + + /* busy scanning */ + if (local->scan_req) + goto unlock; + + /* fill internal scan request */ + if (!channels) { + int max_n; + + for (band = 0; band < NUM_NL80211_BANDS; band++) { + if (!local->hw.wiphy->bands[band]) + continue; + + max_n = local->hw.wiphy->bands[band]->n_channels; + for (i = 0; i < max_n; i++) { + struct ieee80211_channel *tmp_ch = + &local->hw.wiphy->bands[band]->channels[i]; + + if (tmp_ch->flags & (IEEE80211_CHAN_NO_IR | + IEEE80211_CHAN_DISABLED)) + continue; + + local->int_scan_req->channels[n_ch] = tmp_ch; + n_ch++; + } + } + + if (WARN_ON_ONCE(n_ch == 0)) + goto unlock; + + local->int_scan_req->n_channels = n_ch; + } else { + for (i = 0; i < n_channels; i++) { + if (channels[i]->flags & (IEEE80211_CHAN_NO_IR | + IEEE80211_CHAN_DISABLED)) + continue; + + local->int_scan_req->channels[n_ch] = channels[i]; + n_ch++; + } + + if (WARN_ON_ONCE(n_ch == 0)) + goto unlock; + + local->int_scan_req->n_channels = n_ch; + } + + local->int_scan_req->ssids = &local->scan_ssid; + local->int_scan_req->n_ssids = 1; + local->int_scan_req->scan_width = scan_width; + 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->mtx); + return ret; +} + +/* + * Only call this function when a scan can't be queued -- under RTNL. + */ +void ieee80211_scan_cancel(struct ieee80211_local *local) +{ + /* + * We are canceling software scan, or deferred scan that was not + * yet really started (see __ieee80211_start_scan ). + * + * Regarding hardware scan: + * - we can not call __ieee80211_scan_completed() as when + * SCAN_HW_SCANNING bit is set this function change + * local->hw_scan_req to operate on 5G band, what race with + * driver which can use local->hw_scan_req + * + * - we can not cancel scan_work since driver can schedule it + * by ieee80211_scan_completed(..., true) to finish scan + * + * Hence we only call the cancel_hw_scan() callback, but the low-level + * driver is still responsible for calling ieee80211_scan_completed() + * after the scan was completed/aborted. + */ + + mutex_lock(&local->mtx); + if (!local->scan_req) + goto out; + + /* + * We have a scan running and the driver already reported completion, + * but the worker hasn't run yet or is stuck on the mutex - mark it as + * cancelled. + */ + if (test_bit(SCAN_HW_SCANNING, &local->scanning) && + test_bit(SCAN_COMPLETED, &local->scanning)) { + set_bit(SCAN_HW_CANCELLED, &local->scanning); + goto out; + } + + if (test_bit(SCAN_HW_SCANNING, &local->scanning)) { + /* + * Make sure that __ieee80211_scan_completed doesn't trigger a + * scan on another band. + */ + set_bit(SCAN_HW_CANCELLED, &local->scanning); + if (local->ops->cancel_hw_scan) + drv_cancel_hw_scan(local, + rcu_dereference_protected(local->scan_sdata, + lockdep_is_held(&local->mtx))); + goto out; + } + + /* + * If the work is currently running, it must be blocked on + * the mutex, but we'll set scan_sdata = NULL and it'll + * simply exit once it acquires the mutex. + */ + cancel_delayed_work(&local->scan_work); + /* and clean up */ + memset(&local->scan_info, 0, sizeof(local->scan_info)); + __ieee80211_scan_completed(&local->hw, true); +out: + mutex_unlock(&local->mtx); +} + +int __ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, + struct cfg80211_sched_scan_request *req) +{ + struct ieee80211_local *local = sdata->local; + struct ieee80211_scan_ies sched_scan_ies = {}; + struct cfg80211_chan_def chandef; + int ret, i, iebufsz, num_bands = 0; + u32 rate_masks[NUM_NL80211_BANDS] = {}; + u8 bands_used = 0; + u8 *ie; + u32 flags = 0; + + iebufsz = local->scan_ies_len + req->ie_len; + + lockdep_assert_held(&local->mtx); + + if (!local->ops->sched_scan_start) + return -ENOTSUPP; + + for (i = 0; i < NUM_NL80211_BANDS; i++) { + if (local->hw.wiphy->bands[i]) { + bands_used |= BIT(i); + rate_masks[i] = (u32) -1; + num_bands++; + } + } + + if (req->flags & NL80211_SCAN_FLAG_MIN_PREQ_CONTENT) + flags |= IEEE80211_PROBE_FLAG_MIN_CONTENT; + + ie = kcalloc(iebufsz, num_bands, GFP_KERNEL); + if (!ie) { + ret = -ENOMEM; + goto out; + } + + ieee80211_prepare_scan_chandef(&chandef, req->scan_width); + + ieee80211_build_preq_ies(local, ie, num_bands * iebufsz, + &sched_scan_ies, req->ie, + req->ie_len, bands_used, rate_masks, &chandef, + flags); + + ret = drv_sched_scan_start(local, sdata, req, &sched_scan_ies); + if (ret == 0) { + rcu_assign_pointer(local->sched_scan_sdata, sdata); + rcu_assign_pointer(local->sched_scan_req, req); + } + + kfree(ie); + +out: + if (ret) { + /* Clean in case of failure after HW restart or upon resume. */ + RCU_INIT_POINTER(local->sched_scan_sdata, NULL); + RCU_INIT_POINTER(local->sched_scan_req, NULL); + } + + return ret; +} + +int ieee80211_request_sched_scan_start(struct ieee80211_sub_if_data *sdata, + struct cfg80211_sched_scan_request *req) +{ + struct ieee80211_local *local = sdata->local; + int ret; + + mutex_lock(&local->mtx); + + if (rcu_access_pointer(local->sched_scan_sdata)) { + mutex_unlock(&local->mtx); + return -EBUSY; + } + + ret = __ieee80211_request_sched_scan_start(sdata, req); + + mutex_unlock(&local->mtx); + return ret; +} + +int ieee80211_request_sched_scan_stop(struct ieee80211_local *local) +{ + struct ieee80211_sub_if_data *sched_scan_sdata; + int ret = -ENOENT; + + mutex_lock(&local->mtx); + + if (!local->ops->sched_scan_stop) { + ret = -ENOTSUPP; + goto out; + } + + /* We don't want to restart sched scan anymore. */ + RCU_INIT_POINTER(local->sched_scan_req, NULL); + + sched_scan_sdata = rcu_dereference_protected(local->sched_scan_sdata, + lockdep_is_held(&local->mtx)); + if (sched_scan_sdata) { + ret = drv_sched_scan_stop(local, sched_scan_sdata); + if (!ret) + RCU_INIT_POINTER(local->sched_scan_sdata, NULL); + } +out: + mutex_unlock(&local->mtx); + + return ret; +} + +void ieee80211_sched_scan_results(struct ieee80211_hw *hw) +{ + struct ieee80211_local *local = hw_to_local(hw); + + trace_api_sched_scan_results(local); + + cfg80211_sched_scan_results(hw->wiphy, 0); +} +EXPORT_SYMBOL(ieee80211_sched_scan_results); + +void ieee80211_sched_scan_end(struct ieee80211_local *local) +{ + mutex_lock(&local->mtx); + + if (!rcu_access_pointer(local->sched_scan_sdata)) { + mutex_unlock(&local->mtx); + return; + } + + RCU_INIT_POINTER(local->sched_scan_sdata, NULL); + + /* If sched scan was aborted by the driver. */ + RCU_INIT_POINTER(local->sched_scan_req, NULL); + + mutex_unlock(&local->mtx); + + cfg80211_sched_scan_stopped(local->hw.wiphy, 0); +} + +void ieee80211_sched_scan_stopped_work(struct work_struct *work) +{ + struct ieee80211_local *local = + container_of(work, struct ieee80211_local, + sched_scan_stopped_work); + + ieee80211_sched_scan_end(local); +} + +void ieee80211_sched_scan_stopped(struct ieee80211_hw *hw) +{ + struct ieee80211_local *local = hw_to_local(hw); + + trace_api_sched_scan_stopped(local); + + /* + * this shouldn't really happen, so for simplicity + * simply ignore it, and let mac80211 reconfigure + * the sched scan later on. + */ + if (local->in_reconfig) + return; + + schedule_work(&local->sched_scan_stopped_work); +} +EXPORT_SYMBOL(ieee80211_sched_scan_stopped); |