net/mac80211/status.c

   1 /*
   2  * Copyright 2002-2005, Instant802 Networks, Inc.
   3  * Copyright 2005-2006, Devicescape Software, Inc.
   4  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   5  * Copyright 2008-2010  Johannes Berg <johannes@sipsolutions.net>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <net/mac80211.h>
  13 #include "ieee80211_i.h"
  14 #include "rate.h"
  15 #include "mesh.h"
  16 #include "led.h"
  17
  18
  19 void ieee80211_tx_status_irqsafe(struct ieee80211_hw *hw,
  20                                  struct sk_buff *skb)
  21 {
  22         struct ieee80211_local *local = hw_to_local(hw);
  23         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  24         int tmp;
  25
  26         skb->pkt_type = IEEE80211_TX_STATUS_MSG;
  27         skb_queue_tail(info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS ?
  28                        &local->skb_queue : &local->skb_queue_unreliable, skb);
  29         tmp = skb_queue_len(&local->skb_queue) +
  30                 skb_queue_len(&local->skb_queue_unreliable);
  31         while (tmp > IEEE80211_IRQSAFE_QUEUE_LIMIT &&
  32                (skb = skb_dequeue(&local->skb_queue_unreliable))) {
  33                 dev_kfree_skb_irq(skb);
  34                 tmp--;
  35                 I802_DEBUG_INC(local->tx_status_drop);
  36         }
  37         tasklet_schedule(&local->tasklet);
  38 }
  39 EXPORT_SYMBOL(ieee80211_tx_status_irqsafe);
  40
  41 static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
  42                                             struct sta_info *sta,
  43                                             struct sk_buff *skb)
  44 {
  45         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  46
  47         /*
  48          * This skb 'survived' a round-trip through the driver, and
  49          * hopefully the driver didn't mangle it too badly. However,
  50          * we can definitely not rely on the control information
  51          * being correct. Clear it so we don't get junk there, and
  52          * indicate that it needs new processing, but must not be
  53          * modified/encrypted again.
  54          */
  55         memset(&info->control, 0, sizeof(info->control));
  56
  57         info->control.jiffies = jiffies;
  58         info->control.vif = &sta->sdata->vif;
  59         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING |
  60                        IEEE80211_TX_INTFL_RETRANSMISSION;
  61         info->flags &= ~IEEE80211_TX_TEMPORARY_FLAGS;
  62
  63         sta->tx_filtered_count++;
  64
  65         /*
  66          * Clear the TX filter mask for this STA when sending the next
  67          * packet. If the STA went to power save mode, this will happen
  68          * when it wakes up for the next time.
  69          */
  70         set_sta_flags(sta, WLAN_STA_CLEAR_PS_FILT);
  71
  72         /*
  73          * This code races in the following way:
  74          *
  75          *  (1) STA sends frame indicating it will go to sleep and does so
  76          *  (2) hardware/firmware adds STA to filter list, passes frame up
  77          *  (3) hardware/firmware processes TX fifo and suppresses a frame
  78          *  (4) we get TX status before having processed the frame and
  79          *      knowing that the STA has gone to sleep.
  80          *
  81          * This is actually quite unlikely even when both those events are
  82          * processed from interrupts coming in quickly after one another or
  83          * even at the same time because we queue both TX status events and
  84          * RX frames to be processed by a tasklet and process them in the
  85          * same order that they were received or TX status last. Hence, there
  86          * is no race as long as the frame RX is processed before the next TX
  87          * status, which drivers can ensure, see below.
  88          *
  89          * Note that this can only happen if the hardware or firmware can
  90          * actually add STAs to the filter list, if this is done by the
  91          * driver in response to set_tim() (which will only reduce the race
  92          * this whole filtering tries to solve, not completely solve it)
  93          * this situation cannot happen.
  94          *
  95          * To completely solve this race drivers need to make sure that they
  96          *  (a) don't mix the irq-safe/not irq-safe TX status/RX processing
  97          *      functions and
  98          *  (b) always process RX events before TX status events if ordering
  99          *      can be unknown, for example with different interrupt status
 100          *      bits.
 101          */
 102         if (test_sta_flags(sta, WLAN_STA_PS_STA) &&
 103             skb_queue_len(&sta->tx_filtered) < STA_MAX_TX_BUFFER) {
 104                 skb_queue_tail(&sta->tx_filtered, skb);
 105                 return;
 106         }
 107
 108         if (!test_sta_flags(sta, WLAN_STA_PS_STA) &&
 109             !(info->flags & IEEE80211_TX_INTFL_RETRIED)) {
 110                 /* Software retry the packet once */
 111                 info->flags |= IEEE80211_TX_INTFL_RETRIED;
 112                 ieee80211_add_pending_skb(local, skb);
 113                 return;
 114         }
 115
 116 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
 117         if (net_ratelimit())
 118                 wiphy_debug(local->hw.wiphy,
 119                             "dropped TX filtered frame, queue_len=%d PS=%d @%lu\n",
 120                             skb_queue_len(&sta->tx_filtered),
 121                             !!test_sta_flags(sta, WLAN_STA_PS_STA), jiffies);
 122 #endif
 123         dev_kfree_skb(skb);
 124 }
 125
 126 static void ieee80211_frame_acked(struct sta_info *sta, struct sk_buff *skb)
 127 {
 128         struct ieee80211_mgmt *mgmt = (void *) skb->data;
 129         struct ieee80211_local *local = sta->local;
 130         struct ieee80211_sub_if_data *sdata = sta->sdata;
 131
 132         if (ieee80211_is_action(mgmt->frame_control) &&
 133             sdata->vif.type == NL80211_IFTYPE_STATION &&
 134             mgmt->u.action.category == WLAN_CATEGORY_HT &&
 135             mgmt->u.action.u.ht_smps.action == WLAN_HT_ACTION_SMPS) {
 136                 /*
 137                  * This update looks racy, but isn't -- if we come
 138                  * here we've definitely got a station that we're
 139                  * talking to, and on a managed interface that can
 140                  * only be the AP. And the only other place updating
 141                  * this variable is before we're associated.
 142                  */
 143                 switch (mgmt->u.action.u.ht_smps.smps_control) {
 144                 case WLAN_HT_SMPS_CONTROL_DYNAMIC:
 145                         sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_DYNAMIC;
 146                         break;
 147                 case WLAN_HT_SMPS_CONTROL_STATIC:
 148                         sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_STATIC;
 149                         break;
 150                 case WLAN_HT_SMPS_CONTROL_DISABLED:
 151                 default: /* shouldn't happen since we don't send that */
 152                         sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_OFF;
 153                         break;
 154                 }
 155
 156                 ieee80211_queue_work(&local->hw, &local->recalc_smps);
 157         }
 158 }
 159
 160 /*
 161  * Use a static threshold for now, best value to be determined
 162  * by testing ...
 163  * Should it depend on:
 164  *  - on # of retransmissions
 165  *  - current throughput (higher value for higher tpt)?
 166  */
 167 #define STA_LOST_PKT_THRESHOLD  50
 168
 169 void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 170 {
 171         struct sk_buff *skb2;
 172         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 173         struct ieee80211_local *local = hw_to_local(hw);
 174         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 175         u16 frag, type;
 176         __le16 fc;
 177         struct ieee80211_supported_band *sband;
 178         struct ieee80211_tx_status_rtap_hdr *rthdr;
 179         struct ieee80211_sub_if_data *sdata;
 180         struct net_device *prev_dev = NULL;
 181         struct sta_info *sta, *tmp;
 182         int retry_count = -1, i;
 183         int rates_idx = -1;
 184         bool send_to_cooked;
 185         bool acked;
 186
 187         for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
 188                 /* the HW cannot have attempted that rate */
 189                 if (i >= hw->max_report_rates) {
 190                         info->status.rates[i].idx = -1;
 191                         info->status.rates[i].count = 0;
 192                 } else if (info->status.rates[i].idx >= 0) {
 193                         rates_idx = i;
 194                 }
 195
 196                 retry_count += info->status.rates[i].count;
 197         }
 198         if (retry_count < 0)
 199                 retry_count = 0;
 200
 201         rcu_read_lock();
 202
 203         sband = local->hw.wiphy->bands[info->band];
 204         fc = hdr->frame_control;
 205
 206         for_each_sta_info(local, hdr->addr1, sta, tmp) {
 207                 /* skip wrong virtual interface */
 208                 if (memcmp(hdr->addr2, sta->sdata->vif.addr, ETH_ALEN))
 209                         continue;
 210
 211                 acked = !!(info->flags & IEEE80211_TX_STAT_ACK);
 212                 if (!acked && test_sta_flags(sta, WLAN_STA_PS_STA)) {
 213                         /*
 214                          * The STA is in power save mode, so assume
 215                          * that this TX packet failed because of that.
 216                          */
 217                         ieee80211_handle_filtered_frame(local, sta, skb);
 218                         rcu_read_unlock();
 219                         return;
 220                 }
 221
 222                 if ((local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) &&
 223                     (rates_idx != -1))
 224                         sta->last_tx_rate = info->status.rates[rates_idx];
 225
 226                 if ((info->flags & IEEE80211_TX_STAT_AMPDU_NO_BACK) &&
 227                     (ieee80211_is_data_qos(fc))) {
 228                         u16 tid, ssn;
 229                         u8 *qc;
 230
 231                         qc = ieee80211_get_qos_ctl(hdr);
 232                         tid = qc[0] & 0xf;
 233                         ssn = ((le16_to_cpu(hdr->seq_ctrl) + 0x10)
 234                                                 & IEEE80211_SCTL_SEQ);
 235                         ieee80211_send_bar(sta->sdata, hdr->addr1,
 236                                            tid, ssn);
 237                 }
 238
 239                 if (info->flags & IEEE80211_TX_STAT_TX_FILTERED) {
 240                         ieee80211_handle_filtered_frame(local, sta, skb);
 241                         rcu_read_unlock();
 242                         return;
 243                 } else {
 244                         if (!acked)
 245                                 sta->tx_retry_failed++;
 246                         sta->tx_retry_count += retry_count;
 247                 }
 248
 249                 rate_control_tx_status(local, sband, sta, skb);
 250                 if (ieee80211_vif_is_mesh(&sta->sdata->vif))
 251                         ieee80211s_update_metric(local, sta, skb);
 252
 253                 if (!(info->flags & IEEE80211_TX_CTL_INJECTED) && acked)
 254                         ieee80211_frame_acked(sta, skb);
 255
 256                 if ((sta->sdata->vif.type == NL80211_IFTYPE_STATION) &&
 257                     (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS))
 258                         ieee80211_sta_tx_notify(sta->sdata, (void *) skb->data, acked);
 259
 260                 if (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) {
 261                         if (info->flags & IEEE80211_TX_STAT_ACK) {
 262                                 if (sta->lost_packets)
 263                                         sta->lost_packets = 0;
 264                         } else if (++sta->lost_packets >= STA_LOST_PKT_THRESHOLD) {
 265                                 cfg80211_cqm_pktloss_notify(sta->sdata->dev,
 266                                                             sta->sta.addr,
 267                                                             sta->lost_packets,
 268                                                             GFP_ATOMIC);
 269                                 sta->lost_packets = 0;
 270                         }
 271                 }
 272         }
 273
 274         rcu_read_unlock();
 275
 276         ieee80211_led_tx(local, 0);
 277
 278         /* SNMP counters
 279          * Fragments are passed to low-level drivers as separate skbs, so these
 280          * are actually fragments, not frames. Update frame counters only for
 281          * the first fragment of the frame. */
 282
 283         frag = le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_FRAG;
 284         type = le16_to_cpu(hdr->frame_control) & IEEE80211_FCTL_FTYPE;
 285
 286         if (info->flags & IEEE80211_TX_STAT_ACK) {
 287                 if (frag == 0) {
 288                         local->dot11TransmittedFrameCount++;
 289                         if (is_multicast_ether_addr(hdr->addr1))
 290                                 local->dot11MulticastTransmittedFrameCount++;
 291                         if (retry_count > 0)
 292                                 local->dot11RetryCount++;
 293                         if (retry_count > 1)
 294                                 local->dot11MultipleRetryCount++;
 295                 }
 296
 297                 /* This counter shall be incremented for an acknowledged MPDU
 298                  * with an individual address in the address 1 field or an MPDU
 299                  * with a multicast address in the address 1 field of type Data
 300                  * or Management. */
 301                 if (!is_multicast_ether_addr(hdr->addr1) ||
 302                     type == IEEE80211_FTYPE_DATA ||
 303                     type == IEEE80211_FTYPE_MGMT)
 304                         local->dot11TransmittedFragmentCount++;
 305         } else {
 306                 if (frag == 0)
 307                         local->dot11FailedCount++;
 308         }
 309
 310         if (ieee80211_is_nullfunc(fc) && ieee80211_has_pm(fc) &&
 311             (local->hw.flags & IEEE80211_HW_REPORTS_TX_ACK_STATUS) &&
 312             !(info->flags & IEEE80211_TX_CTL_INJECTED) &&
 313             local->ps_sdata && !(local->scanning)) {
 314                 if (info->flags & IEEE80211_TX_STAT_ACK) {
 315                         local->ps_sdata->u.mgd.flags |=
 316                                         IEEE80211_STA_NULLFUNC_ACKED;
 317                         ieee80211_queue_work(&local->hw,
 318                                         &local->dynamic_ps_enable_work);
 319                 } else
 320                         mod_timer(&local->dynamic_ps_timer, jiffies +
 321                                         msecs_to_jiffies(10));
 322         }
 323
 324         if (info->flags & IEEE80211_TX_INTFL_NL80211_FRAME_TX) {
 325                 struct ieee80211_work *wk;
 326
 327                 rcu_read_lock();
 328                 list_for_each_entry_rcu(wk, &local->work_list, list) {
 329                         if (wk->type != IEEE80211_WORK_OFFCHANNEL_TX)
 330                                 continue;
 331                         if (wk->offchan_tx.frame != skb)
 332                                 continue;
 333                         wk->offchan_tx.frame = NULL;
 334                         break;
 335                 }
 336                 rcu_read_unlock();
 337                 cfg80211_mgmt_tx_status(
 338                         skb->dev, (unsigned long) skb, skb->data, skb->len,
 339                         !!(info->flags & IEEE80211_TX_STAT_ACK), GFP_ATOMIC);
 340         }
 341
 342         /* this was a transmitted frame, but now we want to reuse it */
 343         skb_orphan(skb);
 344
 345         /* Need to make a copy before skb->cb gets cleared */
 346         send_to_cooked = !!(info->flags & IEEE80211_TX_CTL_INJECTED) ||
 347                         (type != IEEE80211_FTYPE_DATA);
 348
 349         /*
 350          * This is a bit racy but we can avoid a lot of work
 351          * with this test...
 352          */
 353         if (!local->monitors && (!send_to_cooked || !local->cooked_mntrs)) {
 354                 dev_kfree_skb(skb);
 355                 return;
 356         }
 357
 358         /* send frame to monitor interfaces now */
 359
 360         if (skb_headroom(skb) < sizeof(*rthdr)) {
 361                 printk(KERN_ERR "ieee80211_tx_status: headroom too small\n");
 362                 dev_kfree_skb(skb);
 363                 return;
 364         }
 365
 366         rthdr = (struct ieee80211_tx_status_rtap_hdr *)
 367                                 skb_push(skb, sizeof(*rthdr));
 368
 369         memset(rthdr, 0, sizeof(*rthdr));
 370         rthdr->hdr.it_len = cpu_to_le16(sizeof(*rthdr));
 371         rthdr->hdr.it_present =
 372                 cpu_to_le32((1 << IEEE80211_RADIOTAP_TX_FLAGS) |
 373                             (1 << IEEE80211_RADIOTAP_DATA_RETRIES) |
 374                             (1 << IEEE80211_RADIOTAP_RATE));
 375
 376         if (!(info->flags & IEEE80211_TX_STAT_ACK) &&
 377             !is_multicast_ether_addr(hdr->addr1))
 378                 rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_FAIL);
 379
 380         /*
 381          * XXX: Once radiotap gets the bitmap reset thing the vendor
 382          *      extensions proposal contains, we can actually report
 383          *      the whole set of tries we did.
 384          */
 385         if ((info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS) ||
 386             (info->status.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT))
 387                 rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_CTS);
 388         else if (info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS)
 389                 rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_RTS);
 390         if (info->status.rates[0].idx >= 0 &&
 391             !(info->status.rates[0].flags & IEEE80211_TX_RC_MCS))
 392                 rthdr->rate = sband->bitrates[
 393                                 info->status.rates[0].idx].bitrate / 5;
 394
 395         /* for now report the total retry_count */
 396         rthdr->data_retries = retry_count;
 397
 398         /* XXX: is this sufficient for BPF? */
 399         skb_set_mac_header(skb, 0);
 400         skb->ip_summed = CHECKSUM_UNNECESSARY;
 401         skb->pkt_type = PACKET_OTHERHOST;
 402         skb->protocol = htons(ETH_P_802_2);
 403         memset(skb->cb, 0, sizeof(skb->cb));
 404
 405         rcu_read_lock();
 406         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 407                 if (sdata->vif.type == NL80211_IFTYPE_MONITOR) {
 408                         if (!ieee80211_sdata_running(sdata))
 409                                 continue;
 410
 411                         if ((sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) &&
 412                             !send_to_cooked)
 413                                 continue;
 414
 415                         if (prev_dev) {
 416                                 skb2 = skb_clone(skb, GFP_ATOMIC);
 417                                 if (skb2) {
 418                                         skb2->dev = prev_dev;
 419                                         netif_rx(skb2);
 420                                 }
 421                         }
 422
 423                         prev_dev = sdata->dev;
 424                 }
 425         }
 426         if (prev_dev) {
 427                 skb->dev = prev_dev;
 428                 netif_rx(skb);
 429                 skb = NULL;
 430         }
 431         rcu_read_unlock();
 432         dev_kfree_skb(skb);
 433 }
 434 EXPORT_SYMBOL(ieee80211_tx_status);