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 2008-2009  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 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         info->flags |= IEEE80211_TX_INTFL_NEED_TXPROCESSING |
  57                        IEEE80211_TX_INTFL_RETRANSMISSION;
  58
  59         sta->tx_filtered_count++;
  60
  61         /*
  62          * Clear the TX filter mask for this STA when sending the next
  63          * packet. If the STA went to power save mode, this will happen
  64          * when it wakes up for the next time.
  65          */
  66         set_sta_flags(sta, WLAN_STA_CLEAR_PS_FILT);
  67
  68         /*
  69          * This code races in the following way:
  70          *
  71          *  (1) STA sends frame indicating it will go to sleep and does so
  72          *  (2) hardware/firmware adds STA to filter list, passes frame up
  73          *  (3) hardware/firmware processes TX fifo and suppresses a frame
  74          *  (4) we get TX status before having processed the frame and
  75          *      knowing that the STA has gone to sleep.
  76          *
  77          * This is actually quite unlikely even when both those events are
  78          * processed from interrupts coming in quickly after one another or
  79          * even at the same time because we queue both TX status events and
  80          * RX frames to be processed by a tasklet and process them in the
  81          * same order that they were received or TX status last. Hence, there
  82          * is no race as long as the frame RX is processed before the next TX
  83          * status, which drivers can ensure, see below.
  84          *
  85          * Note that this can only happen if the hardware or firmware can
  86          * actually add STAs to the filter list, if this is done by the
  87          * driver in response to set_tim() (which will only reduce the race
  88          * this whole filtering tries to solve, not completely solve it)
  89          * this situation cannot happen.
  90          *
  91          * To completely solve this race drivers need to make sure that they
  92          *  (a) don't mix the irq-safe/not irq-safe TX status/RX processing
  93          *      functions and
  94          *  (b) always process RX events before TX status events if ordering
  95          *      can be unknown, for example with different interrupt status
  96          *      bits.
  97          */
  98         if (test_sta_flags(sta, WLAN_STA_PS_STA) &&
  99             skb_queue_len(&sta->tx_filtered) < STA_MAX_TX_BUFFER) {
 100                 skb_queue_tail(&sta->tx_filtered, skb);
 101                 return;
 102         }
 103
 104         if (!test_sta_flags(sta, WLAN_STA_PS_STA) &&
 105             !(info->flags & IEEE80211_TX_INTFL_RETRIED)) {
 106                 /* Software retry the packet once */
 107                 info->flags |= IEEE80211_TX_INTFL_RETRIED;
 108                 ieee80211_add_pending_skb(local, skb);
 109                 return;
 110         }
 111
 112 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
 113         if (net_ratelimit())
 114                 printk(KERN_DEBUG "%s: dropped TX filtered frame, "
 115                        "queue_len=%d PS=%d @%lu\n",
 116                        wiphy_name(local->hw.wiphy),
 117                        skb_queue_len(&sta->tx_filtered),
 118                        !!test_sta_flags(sta, WLAN_STA_PS_STA), jiffies);
 119 #endif
 120         dev_kfree_skb(skb);
 121 }
 122
 123 static void ieee80211_frame_acked(struct sta_info *sta, struct sk_buff *skb)
 124 {
 125         struct ieee80211_mgmt *mgmt = (void *) skb->data;
 126         struct ieee80211_local *local = sta->local;
 127         struct ieee80211_sub_if_data *sdata = sta->sdata;
 128
 129         if (ieee80211_is_action(mgmt->frame_control) &&
 130             sdata->vif.type == NL80211_IFTYPE_STATION &&
 131             mgmt->u.action.category == WLAN_CATEGORY_HT &&
 132             mgmt->u.action.u.ht_smps.action == WLAN_HT_ACTION_SMPS) {
 133                 /*
 134                  * This update looks racy, but isn't -- if we come
 135                  * here we've definitely got a station that we're
 136                  * talking to, and on a managed interface that can
 137                  * only be the AP. And the only other place updating
 138                  * this variable is before we're associated.
 139                  */
 140                 switch (mgmt->u.action.u.ht_smps.smps_control) {
 141                 case WLAN_HT_SMPS_CONTROL_DYNAMIC:
 142                         sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_DYNAMIC;
 143                         break;
 144                 case WLAN_HT_SMPS_CONTROL_STATIC:
 145                         sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_STATIC;
 146                         break;
 147                 case WLAN_HT_SMPS_CONTROL_DISABLED:
 148                 default: /* shouldn't happen since we don't send that */
 149                         sta->sdata->u.mgd.ap_smps = IEEE80211_SMPS_OFF;
 150                         break;
 151                 }
 152
 153                 ieee80211_queue_work(&local->hw, &local->recalc_smps);
 154         }
 155 }
 156
 157 void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
 158 {
 159         struct sk_buff *skb2;
 160         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 161         struct ieee80211_local *local = hw_to_local(hw);
 162         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 163         u16 frag, type;
 164         __le16 fc;
 165         struct ieee80211_supported_band *sband;
 166         struct ieee80211_tx_status_rtap_hdr *rthdr;
 167         struct ieee80211_sub_if_data *sdata;
 168         struct net_device *prev_dev = NULL;
 169         struct sta_info *sta, *tmp;
 170         int retry_count = -1, i;
 171         bool injected;
 172
 173         for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
 174                 /* the HW cannot have attempted that rate */
 175                 if (i >= hw->max_rates) {
 176                         info->status.rates[i].idx = -1;
 177                         info->status.rates[i].count = 0;
 178                 }
 179
 180                 retry_count += info->status.rates[i].count;
 181         }
 182         if (retry_count < 0)
 183                 retry_count = 0;
 184
 185         rcu_read_lock();
 186
 187         sband = local->hw.wiphy->bands[info->band];
 188
 189         for_each_sta_info(local, hdr->addr1, sta, tmp) {
 190                 /* skip wrong virtual interface */
 191                 if (memcmp(hdr->addr2, sta->sdata->vif.addr, ETH_ALEN))
 192                         continue;
 193
 194                 if (!(info->flags & IEEE80211_TX_STAT_ACK) &&
 195                     test_sta_flags(sta, WLAN_STA_PS_STA)) {
 196                         /*
 197                          * The STA is in power save mode, so assume
 198                          * that this TX packet failed because of that.
 199                          */
 200                         ieee80211_handle_filtered_frame(local, sta, skb);
 201                         rcu_read_unlock();
 202                         return;
 203                 }
 204
 205                 fc = hdr->frame_control;
 206
 207                 if ((info->flags & IEEE80211_TX_STAT_AMPDU_NO_BACK) &&
 208                     (ieee80211_is_data_qos(fc))) {
 209                         u16 tid, ssn;
 210                         u8 *qc;
 211
 212                         qc = ieee80211_get_qos_ctl(hdr);
 213                         tid = qc[0] & 0xf;
 214                         ssn = ((le16_to_cpu(hdr->seq_ctrl) + 0x10)
 215                                                 & IEEE80211_SCTL_SEQ);
 216                         ieee80211_send_bar(sta->sdata, hdr->addr1,
 217                                            tid, ssn);
 218                 }
 219
 220                 if (info->flags & IEEE80211_TX_STAT_TX_FILTERED) {
 221                         ieee80211_handle_filtered_frame(local, sta, skb);
 222                         rcu_read_unlock();
 223                         return;
 224                 } else {
 225                         if (!(info->flags & IEEE80211_TX_STAT_ACK))
 226                                 sta->tx_retry_failed++;
 227                         sta->tx_retry_count += retry_count;
 228                 }
 229
 230                 rate_control_tx_status(local, sband, sta, skb);
 231                 if (ieee80211_vif_is_mesh(&sta->sdata->vif))
 232                         ieee80211s_update_metric(local, sta, skb);
 233
 234                 if (!(info->flags & IEEE80211_TX_CTL_INJECTED) &&
 235                     (info->flags & IEEE80211_TX_STAT_ACK))
 236                         ieee80211_frame_acked(sta, skb);
 237         }
 238
 239         rcu_read_unlock();
 240
 241         ieee80211_led_tx(local, 0);
 242
 243         /* SNMP counters
 244          * Fragments are passed to low-level drivers as separate skbs, so these
 245          * are actually fragments, not frames. Update frame counters only for
 246          * the first fragment of the frame. */
 247
 248         frag = le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_FRAG;
 249         type = le16_to_cpu(hdr->frame_control) & IEEE80211_FCTL_FTYPE;
 250
 251         if (info->flags & IEEE80211_TX_STAT_ACK) {
 252                 if (frag == 0) {
 253                         local->dot11TransmittedFrameCount++;
 254                         if (is_multicast_ether_addr(hdr->addr1))
 255                                 local->dot11MulticastTransmittedFrameCount++;
 256                         if (retry_count > 0)
 257                                 local->dot11RetryCount++;
 258                         if (retry_count > 1)
 259                                 local->dot11MultipleRetryCount++;
 260                 }
 261
 262                 /* This counter shall be incremented for an acknowledged MPDU
 263                  * with an individual address in the address 1 field or an MPDU
 264                  * with a multicast address in the address 1 field of type Data
 265                  * or Management. */
 266                 if (!is_multicast_ether_addr(hdr->addr1) ||
 267                     type == IEEE80211_FTYPE_DATA ||
 268                     type == IEEE80211_FTYPE_MGMT)
 269                         local->dot11TransmittedFragmentCount++;
 270         } else {
 271                 if (frag == 0)
 272                         local->dot11FailedCount++;
 273         }
 274
 275         /* this was a transmitted frame, but now we want to reuse it */
 276         skb_orphan(skb);
 277
 278         /*
 279          * This is a bit racy but we can avoid a lot of work
 280          * with this test...
 281          */
 282         if (!local->monitors && !local->cooked_mntrs) {
 283                 dev_kfree_skb(skb);
 284                 return;
 285         }
 286
 287         /* send frame to monitor interfaces now */
 288
 289         if (skb_headroom(skb) < sizeof(*rthdr)) {
 290                 printk(KERN_ERR "ieee80211_tx_status: headroom too small\n");
 291                 dev_kfree_skb(skb);
 292                 return;
 293         }
 294
 295         rthdr = (struct ieee80211_tx_status_rtap_hdr *)
 296                                 skb_push(skb, sizeof(*rthdr));
 297
 298         memset(rthdr, 0, sizeof(*rthdr));
 299         rthdr->hdr.it_len = cpu_to_le16(sizeof(*rthdr));
 300         rthdr->hdr.it_present =
 301                 cpu_to_le32((1 << IEEE80211_RADIOTAP_TX_FLAGS) |
 302                             (1 << IEEE80211_RADIOTAP_DATA_RETRIES) |
 303                             (1 << IEEE80211_RADIOTAP_RATE));
 304
 305         if (!(info->flags & IEEE80211_TX_STAT_ACK) &&
 306             !is_multicast_ether_addr(hdr->addr1))
 307                 rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_FAIL);
 308
 309         /*
 310          * XXX: Once radiotap gets the bitmap reset thing the vendor
 311          *      extensions proposal contains, we can actually report
 312          *      the whole set of tries we did.
 313          */
 314         if ((info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS) ||
 315             (info->status.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT))
 316                 rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_CTS);
 317         else if (info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS)
 318                 rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_RTS);
 319         if (info->status.rates[0].idx >= 0 &&
 320             !(info->status.rates[0].flags & IEEE80211_TX_RC_MCS))
 321                 rthdr->rate = sband->bitrates[
 322                                 info->status.rates[0].idx].bitrate / 5;
 323
 324         /* for now report the total retry_count */
 325         rthdr->data_retries = retry_count;
 326
 327         /* Need to make a copy before skb->cb gets cleared */
 328         injected = !!(info->flags & IEEE80211_TX_CTL_INJECTED);
 329
 330         /* XXX: is this sufficient for BPF? */
 331         skb_set_mac_header(skb, 0);
 332         skb->ip_summed = CHECKSUM_UNNECESSARY;
 333         skb->pkt_type = PACKET_OTHERHOST;
 334         skb->protocol = htons(ETH_P_802_2);
 335         memset(skb->cb, 0, sizeof(skb->cb));
 336
 337         rcu_read_lock();
 338         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 339                 if (sdata->vif.type == NL80211_IFTYPE_MONITOR) {
 340                         if (!ieee80211_sdata_running(sdata))
 341                                 continue;
 342
 343                         if ((sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) &&
 344                             !injected &&
 345                             (type == IEEE80211_FTYPE_DATA))
 346                                 continue;
 347
 348                         if (prev_dev) {
 349                                 skb2 = skb_clone(skb, GFP_ATOMIC);
 350                                 if (skb2) {
 351                                         skb2->dev = prev_dev;
 352                                         netif_rx(skb2);
 353                                 }
 354                         }
 355
 356                         prev_dev = sdata->dev;
 357                 }
 358         }
 359         if (prev_dev) {
 360                 skb->dev = prev_dev;
 361                 netif_rx(skb);
 362                 skb = NULL;
 363         }
 364         rcu_read_unlock();
 365         dev_kfree_skb(skb);
 366 }
 367 EXPORT_SYMBOL(ieee80211_tx_status);