net/ieee80211/ieee80211_tx.c

   1 /******************************************************************************
   2
   3   Copyright(c) 2003 - 2005 Intel Corporation. All rights reserved.
   4
   5   This program is free software; you can redistribute it and/or modify it
   6   under the terms of version 2 of the GNU General Public License as
   7   published by the Free Software Foundation.
   8
   9   This program is distributed in the hope that it will be useful, but WITHOUT
  10   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12   more details.
  13
  14   You should have received a copy of the GNU General Public License along with
  15   this program; if not, write to the Free Software Foundation, Inc., 59
  16   Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17
  18   The full GNU General Public License is included in this distribution in the
  19   file called LICENSE.
  20
  21   Contact Information:
  22   James P. Ketrenos <ipw2100-admin@linux.intel.com>
  23   Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
  24
  25 ******************************************************************************/
  26 #include <linux/compiler.h>
  27 #include <linux/errno.h>
  28 #include <linux/if_arp.h>
  29 #include <linux/in6.h>
  30 #include <linux/in.h>
  31 #include <linux/ip.h>
  32 #include <linux/kernel.h>
  33 #include <linux/module.h>
  34 #include <linux/netdevice.h>
  35 #include <linux/proc_fs.h>
  36 #include <linux/skbuff.h>
  37 #include <linux/slab.h>
  38 #include <linux/tcp.h>
  39 #include <linux/types.h>
  40 #include <linux/wireless.h>
  41 #include <linux/etherdevice.h>
  42 #include <asm/uaccess.h>
  43
  44 #include <net/ieee80211.h>
  45
  46 /*
  47
  48 802.11 Data Frame
  49
  50       ,-------------------------------------------------------------------.
  51 Bytes |  2   |  2   |    6    |    6    |    6    |  2   | 0..2312 |   4  |
  52       |------|------|---------|---------|---------|------|---------|------|
  53 Desc. | ctrl | dura |  DA/RA  |   TA    |    SA   | Sequ |  Frame  |  fcs |
  54       |      | tion | (BSSID) |         |         | ence |  data   |      |
  55       `--------------------------------------------------|         |------'
  56 Total: 28 non-data bytes                                 `----.----'
  57                                                               |
  58        .- 'Frame data' expands, if WEP enabled, to <----------'
  59        |
  60        V
  61       ,-----------------------.
  62 Bytes |  4  |   0-2296  |  4  |
  63       |-----|-----------|-----|
  64 Desc. | IV  | Encrypted | ICV |
  65       |     | Packet    |     |
  66       `-----|           |-----'
  67             `-----.-----'
  68                   |
  69        .- 'Encrypted Packet' expands to
  70        |
  71        V
  72       ,---------------------------------------------------.
  73 Bytes |  1   |  1   |    1    |    3     |  2   |  0-2304 |
  74       |------|------|---------|----------|------|---------|
  75 Desc. | SNAP | SNAP | Control |Eth Tunnel| Type | IP      |
  76       | DSAP | SSAP |         |          |      | Packet  |
  77       | 0xAA | 0xAA |0x03 (UI)|0x00-00-F8|      |         |
  78       `----------------------------------------------------
  79 Total: 8 non-data bytes
  80
  81 802.3 Ethernet Data Frame
  82
  83       ,-----------------------------------------.
  84 Bytes |   6   |   6   |  2   |  Variable |   4  |
  85       |-------|-------|------|-----------|------|
  86 Desc. | Dest. | Source| Type | IP Packet |  fcs |
  87       |  MAC  |  MAC  |      |           |      |
  88       `-----------------------------------------'
  89 Total: 18 non-data bytes
  90
  91 In the event that fragmentation is required, the incoming payload is split into
  92 N parts of size ieee->fts.  The first fragment contains the SNAP header and the
  93 remaining packets are just data.
  94
  95 If encryption is enabled, each fragment payload size is reduced by enough space
  96 to add the prefix and postfix (IV and ICV totalling 8 bytes in the case of WEP)
  97 So if you have 1500 bytes of payload with ieee->fts set to 500 without
  98 encryption it will take 3 frames.  With WEP it will take 4 frames as the
  99 payload of each frame is reduced to 492 bytes.
 100
 101 * SKB visualization
 102 *
 103 *  ,- skb->data
 104 * |
 105 * |    ETHERNET HEADER        ,-<-- PAYLOAD
 106 * |                           |     14 bytes from skb->data
 107 * |  2 bytes for Type --> ,T. |     (sizeof ethhdr)
 108 * |                       | | |
 109 * |,-Dest.--. ,--Src.---. | | |
 110 * |  6 bytes| | 6 bytes | | | |
 111 * v         | |         | | | |
 112 * 0         | v       1 | v | v           2
 113 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
 114 *     ^     | ^         | ^ |
 115 *     |     | |         | | |
 116 *     |     | |         | `T' <---- 2 bytes for Type
 117 *     |     | |         |
 118 *     |     | '---SNAP--' <-------- 6 bytes for SNAP
 119 *     |     |
 120 *     `-IV--' <-------------------- 4 bytes for IV (WEP)
 121 *
 122 *      SNAP HEADER
 123 *
 124 */
 125
 126 static u8 P802_1H_OUI[P80211_OUI_LEN] = { 0x00, 0x00, 0xf8 };
 127 static u8 RFC1042_OUI[P80211_OUI_LEN] = { 0x00, 0x00, 0x00 };
 128
 129 static int ieee80211_copy_snap(u8 * data, u16 h_proto)
 130 {
 131         struct ieee80211_snap_hdr *snap;
 132         u8 *oui;
 133
 134         snap = (struct ieee80211_snap_hdr *)data;
 135         snap->dsap = 0xaa;
 136         snap->ssap = 0xaa;
 137         snap->ctrl = 0x03;
 138
 139         if (h_proto == 0x8137 || h_proto == 0x80f3)
 140                 oui = P802_1H_OUI;
 141         else
 142                 oui = RFC1042_OUI;
 143         snap->oui[0] = oui[0];
 144         snap->oui[1] = oui[1];
 145         snap->oui[2] = oui[2];
 146
 147         *(u16 *) (data + SNAP_SIZE) = htons(h_proto);
 148
 149         return SNAP_SIZE + sizeof(u16);
 150 }
 151
 152 static int ieee80211_encrypt_fragment(struct ieee80211_device *ieee,
 153                                              struct sk_buff *frag, int hdr_len)
 154 {
 155         struct ieee80211_crypt_data *crypt = ieee->crypt[ieee->tx_keyidx];
 156         int res;
 157
 158         if (crypt == NULL)
 159                 return -1;
 160
 161         /* To encrypt, frame format is:
 162          * IV (4 bytes), clear payload (including SNAP), ICV (4 bytes) */
 163         atomic_inc(&crypt->refcnt);
 164         res = 0;
 165         if (crypt->ops && crypt->ops->encrypt_mpdu)
 166                 res = crypt->ops->encrypt_mpdu(frag, hdr_len, crypt->priv);
 167
 168         atomic_dec(&crypt->refcnt);
 169         if (res < 0) {
 170                 printk(KERN_INFO "%s: Encryption failed: len=%d.\n",
 171                        ieee->dev->name, frag->len);
 172                 ieee->ieee_stats.tx_discards++;
 173                 return -1;
 174         }
 175
 176         return 0;
 177 }
 178
 179 void ieee80211_txb_free(struct ieee80211_txb *txb)
 180 {
 181         int i;
 182         if (unlikely(!txb))
 183                 return;
 184         for (i = 0; i < txb->nr_frags; i++)
 185                 if (txb->fragments[i])
 186                         dev_kfree_skb_any(txb->fragments[i]);
 187         kfree(txb);
 188 }
 189
 190 static struct ieee80211_txb *ieee80211_alloc_txb(int nr_frags, int txb_size,
 191                                                  int headroom, gfp_t gfp_mask)
 192 {
 193         struct ieee80211_txb *txb;
 194         int i;
 195         txb = kmalloc(sizeof(struct ieee80211_txb) + (sizeof(u8 *) * nr_frags),
 196                       gfp_mask);
 197         if (!txb)
 198                 return NULL;
 199
 200         memset(txb, 0, sizeof(struct ieee80211_txb));
 201         txb->nr_frags = nr_frags;
 202         txb->frag_size = txb_size;
 203
 204         for (i = 0; i < nr_frags; i++) {
 205                 txb->fragments[i] = __dev_alloc_skb(txb_size + headroom,
 206                                                     gfp_mask);
 207                 if (unlikely(!txb->fragments[i])) {
 208                         i--;
 209                         break;
 210                 }
 211                 skb_reserve(txb->fragments[i], headroom);
 212         }
 213         if (unlikely(i != nr_frags)) {
 214                 while (i >= 0)
 215                         dev_kfree_skb_any(txb->fragments[i--]);
 216                 kfree(txb);
 217                 return NULL;
 218         }
 219         return txb;
 220 }
 221
 222 static int ieee80211_classify(struct sk_buff *skb)
 223 {
 224         struct ethhdr *eth;
 225         struct iphdr *ip;
 226
 227         eth = (struct ethhdr *)skb->data;
 228         if (eth->h_proto != htons(ETH_P_IP))
 229                 return 0;
 230
 231         ip = ip_hdr(skb);
 232         switch (ip->tos & 0xfc) {
 233         case 0x20:
 234                 return 2;
 235         case 0x40:
 236                 return 1;
 237         case 0x60:
 238                 return 3;
 239         case 0x80:
 240                 return 4;
 241         case 0xa0:
 242                 return 5;
 243         case 0xc0:
 244                 return 6;
 245         case 0xe0:
 246                 return 7;
 247         default:
 248                 return 0;
 249         }
 250 }
 251
 252 /* Incoming skb is converted to a txb which consists of
 253  * a block of 802.11 fragment packets (stored as skbs) */
 254 int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev)
 255 {
 256         struct ieee80211_device *ieee = netdev_priv(dev);
 257         struct ieee80211_txb *txb = NULL;
 258         struct ieee80211_hdr_3addrqos *frag_hdr;
 259         int i, bytes_per_frag, nr_frags, bytes_last_frag, frag_size,
 260             rts_required;
 261         unsigned long flags;
 262         struct net_device_stats *stats = &ieee->stats;
 263         int ether_type, encrypt, host_encrypt, host_encrypt_msdu, host_build_iv;
 264         int bytes, fc, hdr_len;
 265         struct sk_buff *skb_frag;
 266         struct ieee80211_hdr_3addrqos header = {/* Ensure zero initialized */
 267                 .duration_id = 0,
 268                 .seq_ctl = 0,
 269                 .qos_ctl = 0
 270         };
 271         u8 dest[ETH_ALEN], src[ETH_ALEN];
 272         struct ieee80211_crypt_data *crypt;
 273         int priority = skb->priority;
 274         int snapped = 0;
 275
 276         if (ieee->is_queue_full && (*ieee->is_queue_full) (dev, priority))
 277                 return NETDEV_TX_BUSY;
 278
 279         spin_lock_irqsave(&ieee->lock, flags);
 280
 281         /* If there is no driver handler to take the TXB, dont' bother
 282          * creating it... */
 283         if (!ieee->hard_start_xmit) {
 284                 printk(KERN_WARNING "%s: No xmit handler.\n", ieee->dev->name);
 285                 goto success;
 286         }
 287
 288         if (unlikely(skb->len < SNAP_SIZE + sizeof(u16))) {
 289                 printk(KERN_WARNING "%s: skb too small (%d).\n",
 290                        ieee->dev->name, skb->len);
 291                 goto success;
 292         }
 293
 294         ether_type = ntohs(((struct ethhdr *)skb->data)->h_proto);
 295
 296         crypt = ieee->crypt[ieee->tx_keyidx];
 297
 298         encrypt = !(ether_type == ETH_P_PAE && ieee->ieee802_1x) &&
 299             ieee->sec.encrypt;
 300
 301         host_encrypt = ieee->host_encrypt && encrypt && crypt;
 302         host_encrypt_msdu = ieee->host_encrypt_msdu && encrypt && crypt;
 303         host_build_iv = ieee->host_build_iv && encrypt && crypt;
 304
 305         if (!encrypt && ieee->ieee802_1x &&
 306             ieee->drop_unencrypted && ether_type != ETH_P_PAE) {
 307                 stats->tx_dropped++;
 308                 goto success;
 309         }
 310
 311         /* Save source and destination addresses */
 312         skb_copy_from_linear_data(skb, dest, ETH_ALEN);
 313         skb_copy_from_linear_data_offset(skb, ETH_ALEN, src, ETH_ALEN);
 314
 315         if (host_encrypt || host_build_iv)
 316                 fc = IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA |
 317                     IEEE80211_FCTL_PROTECTED;
 318         else
 319                 fc = IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA;
 320
 321         if (ieee->iw_mode == IW_MODE_INFRA) {
 322                 fc |= IEEE80211_FCTL_TODS;
 323                 /* To DS: Addr1 = BSSID, Addr2 = SA, Addr3 = DA */
 324                 memcpy(header.addr1, ieee->bssid, ETH_ALEN);
 325                 memcpy(header.addr2, src, ETH_ALEN);
 326                 memcpy(header.addr3, dest, ETH_ALEN);
 327         } else if (ieee->iw_mode == IW_MODE_ADHOC) {
 328                 /* not From/To DS: Addr1 = DA, Addr2 = SA, Addr3 = BSSID */
 329                 memcpy(header.addr1, dest, ETH_ALEN);
 330                 memcpy(header.addr2, src, ETH_ALEN);
 331                 memcpy(header.addr3, ieee->bssid, ETH_ALEN);
 332         }
 333         hdr_len = IEEE80211_3ADDR_LEN;
 334
 335         if (ieee->is_qos_active && ieee->is_qos_active(dev, skb)) {
 336                 fc |= IEEE80211_STYPE_QOS_DATA;
 337                 hdr_len += 2;
 338
 339                 skb->priority = ieee80211_classify(skb);
 340                 header.qos_ctl |= cpu_to_le16(skb->priority & IEEE80211_QCTL_TID);
 341         }
 342         header.frame_ctl = cpu_to_le16(fc);
 343
 344         /* Advance the SKB to the start of the payload */
 345         skb_pull(skb, sizeof(struct ethhdr));
 346
 347         /* Determine total amount of storage required for TXB packets */
 348         bytes = skb->len + SNAP_SIZE + sizeof(u16);
 349
 350         /* Encrypt msdu first on the whole data packet. */
 351         if ((host_encrypt || host_encrypt_msdu) &&
 352             crypt && crypt->ops && crypt->ops->encrypt_msdu) {
 353                 int res = 0;
 354                 int len = bytes + hdr_len + crypt->ops->extra_msdu_prefix_len +
 355                     crypt->ops->extra_msdu_postfix_len;
 356                 struct sk_buff *skb_new = dev_alloc_skb(len);
 357
 358                 if (unlikely(!skb_new))
 359                         goto failed;
 360
 361                 skb_reserve(skb_new, crypt->ops->extra_msdu_prefix_len);
 362                 memcpy(skb_put(skb_new, hdr_len), &header, hdr_len);
 363                 snapped = 1;
 364                 ieee80211_copy_snap(skb_put(skb_new, SNAP_SIZE + sizeof(u16)),
 365                                     ether_type);
 366                 skb_copy_from_linear_data(skb, skb_put(skb_new, skb->len), skb->len);
 367                 res = crypt->ops->encrypt_msdu(skb_new, hdr_len, crypt->priv);
 368                 if (res < 0) {
 369                         IEEE80211_ERROR("msdu encryption failed\n");
 370                         dev_kfree_skb_any(skb_new);
 371                         goto failed;
 372                 }
 373                 dev_kfree_skb_any(skb);
 374                 skb = skb_new;
 375                 bytes += crypt->ops->extra_msdu_prefix_len +
 376                     crypt->ops->extra_msdu_postfix_len;
 377                 skb_pull(skb, hdr_len);
 378         }
 379
 380         if (host_encrypt || ieee->host_open_frag) {
 381                 /* Determine fragmentation size based on destination (multicast
 382                  * and broadcast are not fragmented) */
 383                 if (is_multicast_ether_addr(dest) ||
 384                     is_broadcast_ether_addr(dest))
 385                         frag_size = MAX_FRAG_THRESHOLD;
 386                 else
 387                         frag_size = ieee->fts;
 388
 389                 /* Determine amount of payload per fragment.  Regardless of if
 390                  * this stack is providing the full 802.11 header, one will
 391                  * eventually be affixed to this fragment -- so we must account
 392                  * for it when determining the amount of payload space. */
 393                 bytes_per_frag = frag_size - hdr_len;
 394                 if (ieee->config &
 395                     (CFG_IEEE80211_COMPUTE_FCS | CFG_IEEE80211_RESERVE_FCS))
 396                         bytes_per_frag -= IEEE80211_FCS_LEN;
 397
 398                 /* Each fragment may need to have room for encryptiong
 399                  * pre/postfix */
 400                 if (host_encrypt)
 401                         bytes_per_frag -= crypt->ops->extra_mpdu_prefix_len +
 402                             crypt->ops->extra_mpdu_postfix_len;
 403
 404                 /* Number of fragments is the total
 405                  * bytes_per_frag / payload_per_fragment */
 406                 nr_frags = bytes / bytes_per_frag;
 407                 bytes_last_frag = bytes % bytes_per_frag;
 408                 if (bytes_last_frag)
 409                         nr_frags++;
 410                 else
 411                         bytes_last_frag = bytes_per_frag;
 412         } else {
 413                 nr_frags = 1;
 414                 bytes_per_frag = bytes_last_frag = bytes;
 415                 frag_size = bytes + hdr_len;
 416         }
 417
 418         rts_required = (frag_size > ieee->rts
 419                         && ieee->config & CFG_IEEE80211_RTS);
 420         if (rts_required)
 421                 nr_frags++;
 422
 423         /* When we allocate the TXB we allocate enough space for the reserve
 424          * and full fragment bytes (bytes_per_frag doesn't include prefix,
 425          * postfix, header, FCS, etc.) */
 426         txb = ieee80211_alloc_txb(nr_frags, frag_size,
 427                                   ieee->tx_headroom, GFP_ATOMIC);
 428         if (unlikely(!txb)) {
 429                 printk(KERN_WARNING "%s: Could not allocate TXB\n",
 430                        ieee->dev->name);
 431                 goto failed;
 432         }
 433         txb->encrypted = encrypt;
 434         if (host_encrypt)
 435                 txb->payload_size = frag_size * (nr_frags - 1) +
 436                     bytes_last_frag;
 437         else
 438                 txb->payload_size = bytes;
 439
 440         if (rts_required) {
 441                 skb_frag = txb->fragments[0];
 442                 frag_hdr =
 443                     (struct ieee80211_hdr_3addrqos *)skb_put(skb_frag, hdr_len);
 444
 445                 /*
 446                  * Set header frame_ctl to the RTS.
 447                  */
 448                 header.frame_ctl =
 449                     cpu_to_le16(IEEE80211_FTYPE_CTL | IEEE80211_STYPE_RTS);
 450                 memcpy(frag_hdr, &header, hdr_len);
 451
 452                 /*
 453                  * Restore header frame_ctl to the original data setting.
 454                  */
 455                 header.frame_ctl = cpu_to_le16(fc);
 456
 457                 if (ieee->config &
 458                     (CFG_IEEE80211_COMPUTE_FCS | CFG_IEEE80211_RESERVE_FCS))
 459                         skb_put(skb_frag, 4);
 460
 461                 txb->rts_included = 1;
 462                 i = 1;
 463         } else
 464                 i = 0;
 465
 466         for (; i < nr_frags; i++) {
 467                 skb_frag = txb->fragments[i];
 468
 469                 if (host_encrypt || host_build_iv)
 470                         skb_reserve(skb_frag,
 471                                     crypt->ops->extra_mpdu_prefix_len);
 472
 473                 frag_hdr =
 474                     (struct ieee80211_hdr_3addrqos *)skb_put(skb_frag, hdr_len);
 475                 memcpy(frag_hdr, &header, hdr_len);
 476
 477                 /* If this is not the last fragment, then add the MOREFRAGS
 478                  * bit to the frame control */
 479                 if (i != nr_frags - 1) {
 480                         frag_hdr->frame_ctl =
 481                             cpu_to_le16(fc | IEEE80211_FCTL_MOREFRAGS);
 482                         bytes = bytes_per_frag;
 483                 } else {
 484                         /* The last fragment takes the remaining length */
 485                         bytes = bytes_last_frag;
 486                 }
 487
 488                 if (i == 0 && !snapped) {
 489                         ieee80211_copy_snap(skb_put
 490                                             (skb_frag, SNAP_SIZE + sizeof(u16)),
 491                                             ether_type);
 492                         bytes -= SNAP_SIZE + sizeof(u16);
 493                 }
 494
 495                 skb_copy_from_linear_data(skb, skb_put(skb_frag, bytes), bytes);
 496
 497                 /* Advance the SKB... */
 498                 skb_pull(skb, bytes);
 499
 500                 /* Encryption routine will move the header forward in order
 501                  * to insert the IV between the header and the payload */
 502                 if (host_encrypt)
 503                         ieee80211_encrypt_fragment(ieee, skb_frag, hdr_len);
 504                 else if (host_build_iv) {
 505                         atomic_inc(&crypt->refcnt);
 506                         if (crypt->ops->build_iv)
 507                                 crypt->ops->build_iv(skb_frag, hdr_len,
 508                                       ieee->sec.keys[ieee->sec.active_key],
 509                                       ieee->sec.key_sizes[ieee->sec.active_key],
 510                                       crypt->priv);
 511                         atomic_dec(&crypt->refcnt);
 512                 }
 513
 514                 if (ieee->config &
 515                     (CFG_IEEE80211_COMPUTE_FCS | CFG_IEEE80211_RESERVE_FCS))
 516                         skb_put(skb_frag, 4);
 517         }
 518
 519       success:
 520         spin_unlock_irqrestore(&ieee->lock, flags);
 521
 522         dev_kfree_skb_any(skb);
 523
 524         if (txb) {
 525                 int ret = (*ieee->hard_start_xmit) (txb, dev, priority);
 526                 if (ret == 0) {
 527                         stats->tx_packets++;
 528                         stats->tx_bytes += txb->payload_size;
 529                         return 0;
 530                 }
 531
 532                 ieee80211_txb_free(txb);
 533         }
 534
 535         return 0;
 536
 537       failed:
 538         spin_unlock_irqrestore(&ieee->lock, flags);
 539         netif_stop_queue(dev);
 540         stats->tx_errors++;
 541         return 1;
 542 }
 543
 544 /* Incoming 802.11 strucure is converted to a TXB
 545  * a block of 802.11 fragment packets (stored as skbs) */
 546 int ieee80211_tx_frame(struct ieee80211_device *ieee,
 547                        struct ieee80211_hdr *frame, int hdr_len, int total_len,
 548                        int encrypt_mpdu)
 549 {
 550         struct ieee80211_txb *txb = NULL;
 551         unsigned long flags;
 552         struct net_device_stats *stats = &ieee->stats;
 553         struct sk_buff *skb_frag;
 554         int priority = -1;
 555         int fraglen = total_len;
 556         int headroom = ieee->tx_headroom;
 557         struct ieee80211_crypt_data *crypt = ieee->crypt[ieee->tx_keyidx];
 558
 559         spin_lock_irqsave(&ieee->lock, flags);
 560
 561         if (encrypt_mpdu && (!ieee->sec.encrypt || !crypt))
 562                 encrypt_mpdu = 0;
 563
 564         /* If there is no driver handler to take the TXB, dont' bother
 565          * creating it... */
 566         if (!ieee->hard_start_xmit) {
 567                 printk(KERN_WARNING "%s: No xmit handler.\n", ieee->dev->name);
 568                 goto success;
 569         }
 570
 571         if (unlikely(total_len < 24)) {
 572                 printk(KERN_WARNING "%s: skb too small (%d).\n",
 573                        ieee->dev->name, total_len);
 574                 goto success;
 575         }
 576
 577         if (encrypt_mpdu) {
 578                 frame->frame_ctl |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 579                 fraglen += crypt->ops->extra_mpdu_prefix_len +
 580                            crypt->ops->extra_mpdu_postfix_len;
 581                 headroom += crypt->ops->extra_mpdu_prefix_len;
 582         }
 583
 584         /* When we allocate the TXB we allocate enough space for the reserve
 585          * and full fragment bytes (bytes_per_frag doesn't include prefix,
 586          * postfix, header, FCS, etc.) */
 587         txb = ieee80211_alloc_txb(1, fraglen, headroom, GFP_ATOMIC);
 588         if (unlikely(!txb)) {
 589                 printk(KERN_WARNING "%s: Could not allocate TXB\n",
 590                        ieee->dev->name);
 591                 goto failed;
 592         }
 593         txb->encrypted = 0;
 594         txb->payload_size = fraglen;
 595
 596         skb_frag = txb->fragments[0];
 597
 598         memcpy(skb_put(skb_frag, total_len), frame, total_len);
 599
 600         if (ieee->config &
 601             (CFG_IEEE80211_COMPUTE_FCS | CFG_IEEE80211_RESERVE_FCS))
 602                 skb_put(skb_frag, 4);
 603
 604         /* To avoid overcomplicating things, we do the corner-case frame
 605          * encryption in software. The only real situation where encryption is
 606          * needed here is during software-based shared key authentication. */
 607         if (encrypt_mpdu)
 608                 ieee80211_encrypt_fragment(ieee, skb_frag, hdr_len);
 609
 610       success:
 611         spin_unlock_irqrestore(&ieee->lock, flags);
 612
 613         if (txb) {
 614                 if ((*ieee->hard_start_xmit) (txb, ieee->dev, priority) == 0) {
 615                         stats->tx_packets++;
 616                         stats->tx_bytes += txb->payload_size;
 617                         return 0;
 618                 }
 619                 ieee80211_txb_free(txb);
 620         }
 621         return 0;
 622
 623       failed:
 624         spin_unlock_irqrestore(&ieee->lock, flags);
 625         stats->tx_errors++;
 626         return 1;
 627 }
 628
 629 EXPORT_SYMBOL(ieee80211_tx_frame);
 630 EXPORT_SYMBOL(ieee80211_txb_free);