drivers/net/wireless/hostap/hostap_80211_tx.c

   1 #include "hostap_80211.h"
   2 #include "hostap_common.h"
   3 #include "hostap_wlan.h"
   4 #include "hostap.h"
   5 #include "hostap_ap.h"
   6
   7 /* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
   8 /* Ethernet-II snap header (RFC1042 for most EtherTypes) */
   9 static unsigned char rfc1042_header[] =
  10 { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
  11 /* Bridge-Tunnel header (for EtherTypes ETH_P_AARP and ETH_P_IPX) */
  12 static unsigned char bridge_tunnel_header[] =
  13 { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };
  14 /* No encapsulation header if EtherType < 0x600 (=length) */
  15
  16 void hostap_dump_tx_80211(const char *name, struct sk_buff *skb)
  17 {
  18         struct ieee80211_hdr_4addr *hdr;
  19         u16 fc;
  20
  21         hdr = (struct ieee80211_hdr_4addr *) skb->data;
  22
  23         printk(KERN_DEBUG "%s: TX len=%d jiffies=%ld\n",
  24                name, skb->len, jiffies);
  25
  26         if (skb->len < 2)
  27                 return;
  28
  29         fc = le16_to_cpu(hdr->frame_ctl);
  30         printk(KERN_DEBUG "   FC=0x%04x (type=%d:%d)%s%s",
  31                fc, WLAN_FC_GET_TYPE(fc) >> 2, WLAN_FC_GET_STYPE(fc) >> 4,
  32                fc & IEEE80211_FCTL_TODS ? " [ToDS]" : "",
  33                fc & IEEE80211_FCTL_FROMDS ? " [FromDS]" : "");
  34
  35         if (skb->len < IEEE80211_DATA_HDR3_LEN) {
  36                 printk("\n");
  37                 return;
  38         }
  39
  40         printk(" dur=0x%04x seq=0x%04x\n", le16_to_cpu(hdr->duration_id),
  41                le16_to_cpu(hdr->seq_ctl));
  42
  43         printk(KERN_DEBUG "   A1=%pM", hdr->addr1);
  44         printk(" A2=%pM", hdr->addr2);
  45         printk(" A3=%pM", hdr->addr3);
  46         if (skb->len >= 30)
  47                 printk(" A4=%pM", hdr->addr4);
  48         printk("\n");
  49 }
  50
  51
  52 /* hard_start_xmit function for data interfaces (wlan#, wlan#wds#, wlan#sta)
  53  * Convert Ethernet header into a suitable IEEE 802.11 header depending on
  54  * device configuration. */
  55 int hostap_data_start_xmit(struct sk_buff *skb, struct net_device *dev)
  56 {
  57         struct hostap_interface *iface;
  58         local_info_t *local;
  59         int need_headroom, need_tailroom = 0;
  60         struct ieee80211_hdr_4addr hdr;
  61         u16 fc, ethertype = 0;
  62         enum {
  63                 WDS_NO = 0, WDS_OWN_FRAME, WDS_COMPLIANT_FRAME
  64         } use_wds = WDS_NO;
  65         u8 *encaps_data;
  66         int hdr_len, encaps_len, skip_header_bytes;
  67         int to_assoc_ap = 0;
  68         struct hostap_skb_tx_data *meta;
  69
  70         iface = netdev_priv(dev);
  71         local = iface->local;
  72
  73         if (skb->len < ETH_HLEN) {
  74                 printk(KERN_DEBUG "%s: hostap_data_start_xmit: short skb "
  75                        "(len=%d)\n", dev->name, skb->len);
  76                 kfree_skb(skb);
  77                 return 0;
  78         }
  79
  80         if (local->ddev != dev) {
  81                 use_wds = (local->iw_mode == IW_MODE_MASTER &&
  82                            !(local->wds_type & HOSTAP_WDS_STANDARD_FRAME)) ?
  83                         WDS_OWN_FRAME : WDS_COMPLIANT_FRAME;
  84                 if (dev == local->stadev) {
  85                         to_assoc_ap = 1;
  86                         use_wds = WDS_NO;
  87                 } else if (dev == local->apdev) {
  88                         printk(KERN_DEBUG "%s: prism2_tx: trying to use "
  89                                "AP device with Ethernet net dev\n", dev->name);
  90                         kfree_skb(skb);
  91                         return 0;
  92                 }
  93         } else {
  94                 if (local->iw_mode == IW_MODE_REPEAT) {
  95                         printk(KERN_DEBUG "%s: prism2_tx: trying to use "
  96                                "non-WDS link in Repeater mode\n", dev->name);
  97                         kfree_skb(skb);
  98                         return 0;
  99                 } else if (local->iw_mode == IW_MODE_INFRA &&
 100                            (local->wds_type & HOSTAP_WDS_AP_CLIENT) &&
 101                            memcmp(skb->data + ETH_ALEN, dev->dev_addr,
 102                                   ETH_ALEN) != 0) {
 103                         /* AP client mode: send frames with foreign src addr
 104                          * using 4-addr WDS frames */
 105                         use_wds = WDS_COMPLIANT_FRAME;
 106                 }
 107         }
 108
 109         /* Incoming skb->data: dst_addr[6], src_addr[6], proto[2], payload
 110          * ==>
 111          * Prism2 TX frame with 802.11 header:
 112          * txdesc (address order depending on used mode; includes dst_addr and
 113          * src_addr), possible encapsulation (RFC1042/Bridge-Tunnel;
 114          * proto[2], payload {, possible addr4[6]} */
 115
 116         ethertype = (skb->data[12] << 8) | skb->data[13];
 117
 118         memset(&hdr, 0, sizeof(hdr));
 119
 120         /* Length of data after IEEE 802.11 header */
 121         encaps_data = NULL;
 122         encaps_len = 0;
 123         skip_header_bytes = ETH_HLEN;
 124         if (ethertype == ETH_P_AARP || ethertype == ETH_P_IPX) {
 125                 encaps_data = bridge_tunnel_header;
 126                 encaps_len = sizeof(bridge_tunnel_header);
 127                 skip_header_bytes -= 2;
 128         } else if (ethertype >= 0x600) {
 129                 encaps_data = rfc1042_header;
 130                 encaps_len = sizeof(rfc1042_header);
 131                 skip_header_bytes -= 2;
 132         }
 133
 134         fc = IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA;
 135         hdr_len = IEEE80211_DATA_HDR3_LEN;
 136
 137         if (use_wds != WDS_NO) {
 138                 /* Note! Prism2 station firmware has problems with sending real
 139                  * 802.11 frames with four addresses; until these problems can
 140                  * be fixed or worked around, 4-addr frames needed for WDS are
 141                  * using incompatible format: FromDS flag is not set and the
 142                  * fourth address is added after the frame payload; it is
 143                  * assumed, that the receiving station knows how to handle this
 144                  * frame format */
 145
 146                 if (use_wds == WDS_COMPLIANT_FRAME) {
 147                         fc |= IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS;
 148                         /* From&To DS: Addr1 = RA, Addr2 = TA, Addr3 = DA,
 149                          * Addr4 = SA */
 150                         skb_copy_from_linear_data_offset(skb, ETH_ALEN,
 151                                                          &hdr.addr4, ETH_ALEN);
 152                         hdr_len += ETH_ALEN;
 153                 } else {
 154                         /* bogus 4-addr format to workaround Prism2 station
 155                          * f/w bug */
 156                         fc |= IEEE80211_FCTL_TODS;
 157                         /* From DS: Addr1 = DA (used as RA),
 158                          * Addr2 = BSSID (used as TA), Addr3 = SA (used as DA),
 159                          */
 160
 161                         /* SA from skb->data + ETH_ALEN will be added after
 162                          * frame payload; use hdr.addr4 as a temporary buffer
 163                          */
 164                         skb_copy_from_linear_data_offset(skb, ETH_ALEN,
 165                                                          &hdr.addr4, ETH_ALEN);
 166                         need_tailroom += ETH_ALEN;
 167                 }
 168
 169                 /* send broadcast and multicast frames to broadcast RA, if
 170                  * configured; otherwise, use unicast RA of the WDS link */
 171                 if ((local->wds_type & HOSTAP_WDS_BROADCAST_RA) &&
 172                     skb->data[0] & 0x01)
 173                         memset(&hdr.addr1, 0xff, ETH_ALEN);
 174                 else if (iface->type == HOSTAP_INTERFACE_WDS)
 175                         memcpy(&hdr.addr1, iface->u.wds.remote_addr,
 176                                ETH_ALEN);
 177                 else
 178                         memcpy(&hdr.addr1, local->bssid, ETH_ALEN);
 179                 memcpy(&hdr.addr2, dev->dev_addr, ETH_ALEN);
 180                 skb_copy_from_linear_data(skb, &hdr.addr3, ETH_ALEN);
 181         } else if (local->iw_mode == IW_MODE_MASTER && !to_assoc_ap) {
 182                 fc |= IEEE80211_FCTL_FROMDS;
 183                 /* From DS: Addr1 = DA, Addr2 = BSSID, Addr3 = SA */
 184                 skb_copy_from_linear_data(skb, &hdr.addr1, ETH_ALEN);
 185                 memcpy(&hdr.addr2, dev->dev_addr, ETH_ALEN);
 186                 skb_copy_from_linear_data_offset(skb, ETH_ALEN, &hdr.addr3,
 187                                                  ETH_ALEN);
 188         } else if (local->iw_mode == IW_MODE_INFRA || to_assoc_ap) {
 189                 fc |= IEEE80211_FCTL_TODS;
 190                 /* To DS: Addr1 = BSSID, Addr2 = SA, Addr3 = DA */
 191                 memcpy(&hdr.addr1, to_assoc_ap ?
 192                        local->assoc_ap_addr : local->bssid, ETH_ALEN);
 193                 skb_copy_from_linear_data_offset(skb, ETH_ALEN, &hdr.addr2,
 194                                                  ETH_ALEN);
 195                 skb_copy_from_linear_data(skb, &hdr.addr3, ETH_ALEN);
 196         } else if (local->iw_mode == IW_MODE_ADHOC) {
 197                 /* not From/To DS: Addr1 = DA, Addr2 = SA, Addr3 = BSSID */
 198                 skb_copy_from_linear_data(skb, &hdr.addr1, ETH_ALEN);
 199                 skb_copy_from_linear_data_offset(skb, ETH_ALEN, &hdr.addr2,
 200                                                  ETH_ALEN);
 201                 memcpy(&hdr.addr3, local->bssid, ETH_ALEN);
 202         }
 203
 204         hdr.frame_ctl = cpu_to_le16(fc);
 205
 206         skb_pull(skb, skip_header_bytes);
 207         need_headroom = local->func->need_tx_headroom + hdr_len + encaps_len;
 208         if (skb_tailroom(skb) < need_tailroom) {
 209                 skb = skb_unshare(skb, GFP_ATOMIC);
 210                 if (skb == NULL) {
 211                         iface->stats.tx_dropped++;
 212                         return 0;
 213                 }
 214                 if (pskb_expand_head(skb, need_headroom, need_tailroom,
 215                                      GFP_ATOMIC)) {
 216                         kfree_skb(skb);
 217                         iface->stats.tx_dropped++;
 218                         return 0;
 219                 }
 220         } else if (skb_headroom(skb) < need_headroom) {
 221                 struct sk_buff *tmp = skb;
 222                 skb = skb_realloc_headroom(skb, need_headroom);
 223                 kfree_skb(tmp);
 224                 if (skb == NULL) {
 225                         iface->stats.tx_dropped++;
 226                         return 0;
 227                 }
 228         } else {
 229                 skb = skb_unshare(skb, GFP_ATOMIC);
 230                 if (skb == NULL) {
 231                         iface->stats.tx_dropped++;
 232                         return 0;
 233                 }
 234         }
 235
 236         if (encaps_data)
 237                 memcpy(skb_push(skb, encaps_len), encaps_data, encaps_len);
 238         memcpy(skb_push(skb, hdr_len), &hdr, hdr_len);
 239         if (use_wds == WDS_OWN_FRAME) {
 240                 memcpy(skb_put(skb, ETH_ALEN), &hdr.addr4, ETH_ALEN);
 241         }
 242
 243         iface->stats.tx_packets++;
 244         iface->stats.tx_bytes += skb->len;
 245
 246         skb_reset_mac_header(skb);
 247         meta = (struct hostap_skb_tx_data *) skb->cb;
 248         memset(meta, 0, sizeof(*meta));
 249         meta->magic = HOSTAP_SKB_TX_DATA_MAGIC;
 250         if (use_wds)
 251                 meta->flags |= HOSTAP_TX_FLAGS_WDS;
 252         meta->ethertype = ethertype;
 253         meta->iface = iface;
 254
 255         /* Send IEEE 802.11 encapsulated frame using the master radio device */
 256         skb->dev = local->dev;
 257         dev_queue_xmit(skb);
 258         return 0;
 259 }
 260
 261
 262 /* hard_start_xmit function for hostapd wlan#ap interfaces */
 263 int hostap_mgmt_start_xmit(struct sk_buff *skb, struct net_device *dev)
 264 {
 265         struct hostap_interface *iface;
 266         local_info_t *local;
 267         struct hostap_skb_tx_data *meta;
 268         struct ieee80211_hdr_4addr *hdr;
 269         u16 fc;
 270
 271         iface = netdev_priv(dev);
 272         local = iface->local;
 273
 274         if (skb->len < 10) {
 275                 printk(KERN_DEBUG "%s: hostap_mgmt_start_xmit: short skb "
 276                        "(len=%d)\n", dev->name, skb->len);
 277                 kfree_skb(skb);
 278                 return 0;
 279         }
 280
 281         iface->stats.tx_packets++;
 282         iface->stats.tx_bytes += skb->len;
 283
 284         meta = (struct hostap_skb_tx_data *) skb->cb;
 285         memset(meta, 0, sizeof(*meta));
 286         meta->magic = HOSTAP_SKB_TX_DATA_MAGIC;
 287         meta->iface = iface;
 288
 289         if (skb->len >= IEEE80211_DATA_HDR3_LEN + sizeof(rfc1042_header) + 2) {
 290                 hdr = (struct ieee80211_hdr_4addr *) skb->data;
 291                 fc = le16_to_cpu(hdr->frame_ctl);
 292                 if (WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA &&
 293                     WLAN_FC_GET_STYPE(fc) == IEEE80211_STYPE_DATA) {
 294                         u8 *pos = &skb->data[IEEE80211_DATA_HDR3_LEN +
 295                                              sizeof(rfc1042_header)];
 296                         meta->ethertype = (pos[0] << 8) | pos[1];
 297                 }
 298         }
 299
 300         /* Send IEEE 802.11 encapsulated frame using the master radio device */
 301         skb->dev = local->dev;
 302         dev_queue_xmit(skb);
 303         return 0;
 304 }
 305
 306
 307 /* Called only from software IRQ */
 308 static struct sk_buff * hostap_tx_encrypt(struct sk_buff *skb,
 309                                           struct ieee80211_crypt_data *crypt)
 310 {
 311         struct hostap_interface *iface;
 312         local_info_t *local;
 313         struct ieee80211_hdr_4addr *hdr;
 314         u16 fc;
 315         int prefix_len, postfix_len, hdr_len, res;
 316
 317         iface = netdev_priv(skb->dev);
 318         local = iface->local;
 319
 320         if (skb->len < IEEE80211_DATA_HDR3_LEN) {
 321                 kfree_skb(skb);
 322                 return NULL;
 323         }
 324
 325         if (local->tkip_countermeasures &&
 326             strcmp(crypt->ops->name, "TKIP") == 0) {
 327                 hdr = (struct ieee80211_hdr_4addr *) skb->data;
 328                 if (net_ratelimit()) {
 329                         printk(KERN_DEBUG "%s: TKIP countermeasures: dropped "
 330                                "TX packet to %pM\n",
 331                                local->dev->name, hdr->addr1);
 332                 }
 333                 kfree_skb(skb);
 334                 return NULL;
 335         }
 336
 337         skb = skb_unshare(skb, GFP_ATOMIC);
 338         if (skb == NULL)
 339                 return NULL;
 340
 341         prefix_len = crypt->ops->extra_mpdu_prefix_len +
 342                 crypt->ops->extra_msdu_prefix_len;
 343         postfix_len = crypt->ops->extra_mpdu_postfix_len +
 344                 crypt->ops->extra_msdu_postfix_len;
 345         if ((skb_headroom(skb) < prefix_len ||
 346              skb_tailroom(skb) < postfix_len) &&
 347             pskb_expand_head(skb, prefix_len, postfix_len, GFP_ATOMIC)) {
 348                 kfree_skb(skb);
 349                 return NULL;
 350         }
 351
 352         hdr = (struct ieee80211_hdr_4addr *) skb->data;
 353         fc = le16_to_cpu(hdr->frame_ctl);
 354         hdr_len = hostap_80211_get_hdrlen(fc);
 355
 356         /* Host-based IEEE 802.11 fragmentation for TX is not yet supported, so
 357          * call both MSDU and MPDU encryption functions from here. */
 358         atomic_inc(&crypt->refcnt);
 359         res = 0;
 360         if (crypt->ops->encrypt_msdu)
 361                 res = crypt->ops->encrypt_msdu(skb, hdr_len, crypt->priv);
 362         if (res == 0 && crypt->ops->encrypt_mpdu)
 363                 res = crypt->ops->encrypt_mpdu(skb, hdr_len, crypt->priv);
 364         atomic_dec(&crypt->refcnt);
 365         if (res < 0) {
 366                 kfree_skb(skb);
 367                 return NULL;
 368         }
 369
 370         return skb;
 371 }
 372
 373
 374 /* hard_start_xmit function for master radio interface wifi#.
 375  * AP processing (TX rate control, power save buffering, etc.).
 376  * Use hardware TX function to send the frame. */
 377 int hostap_master_start_xmit(struct sk_buff *skb, struct net_device *dev)
 378 {
 379         struct hostap_interface *iface;
 380         local_info_t *local;
 381         int ret = 1;
 382         u16 fc;
 383         struct hostap_tx_data tx;
 384         ap_tx_ret tx_ret;
 385         struct hostap_skb_tx_data *meta;
 386         int no_encrypt = 0;
 387         struct ieee80211_hdr_4addr *hdr;
 388
 389         iface = netdev_priv(dev);
 390         local = iface->local;
 391
 392         tx.skb = skb;
 393         tx.sta_ptr = NULL;
 394
 395         meta = (struct hostap_skb_tx_data *) skb->cb;
 396         if (meta->magic != HOSTAP_SKB_TX_DATA_MAGIC) {
 397                 printk(KERN_DEBUG "%s: invalid skb->cb magic (0x%08x, "
 398                        "expected 0x%08x)\n",
 399                        dev->name, meta->magic, HOSTAP_SKB_TX_DATA_MAGIC);
 400                 ret = 0;
 401                 iface->stats.tx_dropped++;
 402                 goto fail;
 403         }
 404
 405         if (local->host_encrypt) {
 406                 /* Set crypt to default algorithm and key; will be replaced in
 407                  * AP code if STA has own alg/key */
 408                 tx.crypt = local->crypt[local->tx_keyidx];
 409                 tx.host_encrypt = 1;
 410         } else {
 411                 tx.crypt = NULL;
 412                 tx.host_encrypt = 0;
 413         }
 414
 415         if (skb->len < 24) {
 416                 printk(KERN_DEBUG "%s: hostap_master_start_xmit: short skb "
 417                        "(len=%d)\n", dev->name, skb->len);
 418                 ret = 0;
 419                 iface->stats.tx_dropped++;
 420                 goto fail;
 421         }
 422
 423         /* FIX (?):
 424          * Wi-Fi 802.11b test plan suggests that AP should ignore power save
 425          * bit in authentication and (re)association frames and assume tha
 426          * STA remains awake for the response. */
 427         tx_ret = hostap_handle_sta_tx(local, &tx);
 428         skb = tx.skb;
 429         meta = (struct hostap_skb_tx_data *) skb->cb;
 430         hdr = (struct ieee80211_hdr_4addr *) skb->data;
 431         fc = le16_to_cpu(hdr->frame_ctl);
 432         switch (tx_ret) {
 433         case AP_TX_CONTINUE:
 434                 break;
 435         case AP_TX_CONTINUE_NOT_AUTHORIZED:
 436                 if (local->ieee_802_1x &&
 437                     WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA &&
 438                     meta->ethertype != ETH_P_PAE &&
 439                     !(meta->flags & HOSTAP_TX_FLAGS_WDS)) {
 440                         printk(KERN_DEBUG "%s: dropped frame to unauthorized "
 441                                "port (IEEE 802.1X): ethertype=0x%04x\n",
 442                                dev->name, meta->ethertype);
 443                         hostap_dump_tx_80211(dev->name, skb);
 444
 445                         ret = 0; /* drop packet */
 446                         iface->stats.tx_dropped++;
 447                         goto fail;
 448                 }
 449                 break;
 450         case AP_TX_DROP:
 451                 ret = 0; /* drop packet */
 452                 iface->stats.tx_dropped++;
 453                 goto fail;
 454         case AP_TX_RETRY:
 455                 goto fail;
 456         case AP_TX_BUFFERED:
 457                 /* do not free skb here, it will be freed when the
 458                  * buffered frame is sent/timed out */
 459                 ret = 0;
 460                 goto tx_exit;
 461         }
 462
 463         /* Request TX callback if protocol version is 2 in 802.11 header;
 464          * this version 2 is a special case used between hostapd and kernel
 465          * driver */
 466         if (((fc & IEEE80211_FCTL_VERS) == BIT(1)) &&
 467             local->ap && local->ap->tx_callback_idx && meta->tx_cb_idx == 0) {
 468                 meta->tx_cb_idx = local->ap->tx_callback_idx;
 469
 470                 /* remove special version from the frame header */
 471                 fc &= ~IEEE80211_FCTL_VERS;
 472                 hdr->frame_ctl = cpu_to_le16(fc);
 473         }
 474
 475         if (WLAN_FC_GET_TYPE(fc) != IEEE80211_FTYPE_DATA) {
 476                 no_encrypt = 1;
 477                 tx.crypt = NULL;
 478         }
 479
 480         if (local->ieee_802_1x && meta->ethertype == ETH_P_PAE && tx.crypt &&
 481             !(fc & IEEE80211_FCTL_PROTECTED)) {
 482                 no_encrypt = 1;
 483                 PDEBUG(DEBUG_EXTRA2, "%s: TX: IEEE 802.1X - passing "
 484                        "unencrypted EAPOL frame\n", dev->name);
 485                 tx.crypt = NULL; /* no encryption for IEEE 802.1X frames */
 486         }
 487
 488         if (tx.crypt && (!tx.crypt->ops || !tx.crypt->ops->encrypt_mpdu))
 489                 tx.crypt = NULL;
 490         else if ((tx.crypt || local->crypt[local->tx_keyidx]) && !no_encrypt) {
 491                 /* Add ISWEP flag both for firmware and host based encryption
 492                  */
 493                 fc |= IEEE80211_FCTL_PROTECTED;
 494                 hdr->frame_ctl = cpu_to_le16(fc);
 495         } else if (local->drop_unencrypted &&
 496                    WLAN_FC_GET_TYPE(fc) == IEEE80211_FTYPE_DATA &&
 497                    meta->ethertype != ETH_P_PAE) {
 498                 if (net_ratelimit()) {
 499                         printk(KERN_DEBUG "%s: dropped unencrypted TX data "
 500                                "frame (drop_unencrypted=1)\n", dev->name);
 501                 }
 502                 iface->stats.tx_dropped++;
 503                 ret = 0;
 504                 goto fail;
 505         }
 506
 507         if (tx.crypt) {
 508                 skb = hostap_tx_encrypt(skb, tx.crypt);
 509                 if (skb == NULL) {
 510                         printk(KERN_DEBUG "%s: TX - encryption failed\n",
 511                                dev->name);
 512                         ret = 0;
 513                         goto fail;
 514                 }
 515                 meta = (struct hostap_skb_tx_data *) skb->cb;
 516                 if (meta->magic != HOSTAP_SKB_TX_DATA_MAGIC) {
 517                         printk(KERN_DEBUG "%s: invalid skb->cb magic (0x%08x, "
 518                                "expected 0x%08x) after hostap_tx_encrypt\n",
 519                                dev->name, meta->magic,
 520                                HOSTAP_SKB_TX_DATA_MAGIC);
 521                         ret = 0;
 522                         iface->stats.tx_dropped++;
 523                         goto fail;
 524                 }
 525         }
 526
 527         if (local->func->tx == NULL || local->func->tx(skb, dev)) {
 528                 ret = 0;
 529                 iface->stats.tx_dropped++;
 530         } else {
 531                 ret = 0;
 532                 iface->stats.tx_packets++;
 533                 iface->stats.tx_bytes += skb->len;
 534         }
 535
 536  fail:
 537         if (!ret && skb)
 538                 dev_kfree_skb(skb);
 539  tx_exit:
 540         if (tx.sta_ptr)
 541                 hostap_handle_sta_release(tx.sta_ptr);
 542         return ret;
 543 }
 544
 545
 546 EXPORT_SYMBOL(hostap_master_start_xmit);