drivers/net/wireless/ipw2x00/libipw_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   Intel Linux Wireless <ilw@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 "libipw.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 libipw_copy_snap(u8 * data, __be16 h_proto)
 130 {
 131         struct libipw_snap_hdr *snap;
 132         u8 *oui;
 133
 134         snap = (struct libipw_snap_hdr *)data;
 135         snap->dsap = 0xaa;
 136         snap->ssap = 0xaa;
 137         snap->ctrl = 0x03;
 138
 139         if (h_proto == htons(ETH_P_AARP) || h_proto == htons(ETH_P_IPX))
 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         memcpy(data + SNAP_SIZE, &h_proto, sizeof(u16));
 148
 149         return SNAP_SIZE + sizeof(u16);
 150 }
 151
 152 static int libipw_encrypt_fragment(struct libipw_device *ieee,
 153                                              struct sk_buff *frag, int hdr_len)
 154 {
 155         struct lib80211_crypt_data *crypt =
 156                 ieee->crypt_info.crypt[ieee->crypt_info.tx_keyidx];
 157         int res;
 158
 159         if (crypt == NULL)
 160                 return -1;
 161
 162         /* To encrypt, frame format is:
 163          * IV (4 bytes), clear payload (including SNAP), ICV (4 bytes) */
 164         atomic_inc(&crypt->refcnt);
 165         res = 0;
 166         if (crypt->ops && crypt->ops->encrypt_mpdu)
 167                 res = crypt->ops->encrypt_mpdu(frag, hdr_len, crypt->priv);
 168
 169         atomic_dec(&crypt->refcnt);
 170         if (res < 0) {
 171                 printk(KERN_INFO "%s: Encryption failed: len=%d.\n",
 172                        ieee->dev->name, frag->len);
 173                 ieee->ieee_stats.tx_discards++;
 174                 return -1;
 175         }
 176
 177         return 0;
 178 }
 179
 180 void libipw_txb_free(struct libipw_txb *txb)
 181 {
 182         int i;
 183         if (unlikely(!txb))
 184                 return;
 185         for (i = 0; i < txb->nr_frags; i++)
 186                 if (txb->fragments[i])
 187                         dev_kfree_skb_any(txb->fragments[i]);
 188         kfree(txb);
 189 }
 190
 191 static struct libipw_txb *libipw_alloc_txb(int nr_frags, int txb_size,
 192                                                  int headroom, gfp_t gfp_mask)
 193 {
 194         struct libipw_txb *txb;
 195         int i;
 196         txb = kmalloc(sizeof(struct libipw_txb) + (sizeof(u8 *) * nr_frags),
 197                       gfp_mask);
 198         if (!txb)
 199                 return NULL;
 200
 201         memset(txb, 0, sizeof(struct libipw_txb));
 202         txb->nr_frags = nr_frags;
 203         txb->frag_size = txb_size;
 204
 205         for (i = 0; i < nr_frags; i++) {
 206                 txb->fragments[i] = __dev_alloc_skb(txb_size + headroom,
 207                                                     gfp_mask);
 208                 if (unlikely(!txb->fragments[i])) {
 209                         i--;
 210                         break;
 211                 }
 212                 skb_reserve(txb->fragments[i], headroom);
 213         }
 214         if (unlikely(i != nr_frags)) {
 215                 while (i >= 0)
 216                         dev_kfree_skb_any(txb->fragments[i--]);
 217                 kfree(txb);
 218                 return NULL;
 219         }
 220         return txb;
 221 }
 222
 223 static int libipw_classify(struct sk_buff *skb)
 224 {
 225         struct ethhdr *eth;
 226         struct iphdr *ip;
 227
 228         eth = (struct ethhdr *)skb->data;
 229         if (eth->h_proto != htons(ETH_P_IP))
 230                 return 0;
 231
 232         ip = ip_hdr(skb);
 233         switch (ip->tos & 0xfc) {
 234         case 0x20:
 235                 return 2;
 236         case 0x40:
 237                 return 1;
 238         case 0x60:
 239                 return 3;
 240         case 0x80:
 241                 return 4;
 242         case 0xa0:
 243                 return 5;
 244         case 0xc0:
 245                 return 6;
 246         case 0xe0:
 247                 return 7;
 248         default:
 249                 return 0;
 250         }
 251 }
 252
 253 /* Incoming skb is converted to a txb which consists of
 254  * a block of 802.11 fragment packets (stored as skbs) */
 255 netdev_tx_t libipw_xmit(struct sk_buff *skb, struct net_device *dev)
 256 {
 257         struct libipw_device *ieee = netdev_priv(dev);
 258         struct libipw_txb *txb = NULL;
 259         struct libipw_hdr_3addrqos *frag_hdr;
 260         int i, bytes_per_frag, nr_frags, bytes_last_frag, frag_size,
 261             rts_required;
 262         unsigned long flags;
 263         int encrypt, host_encrypt, host_encrypt_msdu, host_build_iv;
 264         __be16 ether_type;
 265         int bytes, fc, hdr_len;
 266         struct sk_buff *skb_frag;
 267         struct libipw_hdr_3addrqos header = {/* Ensure zero initialized */
 268                 .duration_id = 0,
 269                 .seq_ctl = 0,
 270                 .qos_ctl = 0
 271         };
 272         u8 dest[ETH_ALEN], src[ETH_ALEN];
 273         struct lib80211_crypt_data *crypt;
 274         int priority = skb->priority;
 275         int snapped = 0;
 276
 277         if (ieee->is_queue_full && (*ieee->is_queue_full) (dev, priority))
 278                 return NETDEV_TX_BUSY;
 279
 280         spin_lock_irqsave(&ieee->lock, flags);
 281
 282         /* If there is no driver handler to take the TXB, dont' bother
 283          * creating it... */
 284         if (!ieee->hard_start_xmit) {
 285                 printk(KERN_WARNING "%s: No xmit handler.\n", ieee->dev->name);
 286                 goto success;
 287         }
 288
 289         if (unlikely(skb->len < SNAP_SIZE + sizeof(u16))) {
 290                 printk(KERN_WARNING "%s: skb too small (%d).\n",
 291                        ieee->dev->name, skb->len);
 292                 goto success;
 293         }
 294
 295         ether_type = ((struct ethhdr *)skb->data)->h_proto;
 296
 297         crypt = ieee->crypt_info.crypt[ieee->crypt_info.tx_keyidx];
 298
 299         encrypt = !(ether_type == htons(ETH_P_PAE) && ieee->ieee802_1x) &&
 300             ieee->sec.encrypt;
 301
 302         host_encrypt = ieee->host_encrypt && encrypt && crypt;
 303         host_encrypt_msdu = ieee->host_encrypt_msdu && encrypt && crypt;
 304         host_build_iv = ieee->host_build_iv && encrypt && crypt;
 305
 306         if (!encrypt && ieee->ieee802_1x &&
 307             ieee->drop_unencrypted && ether_type != htons(ETH_P_PAE)) {
 308                 dev->stats.tx_dropped++;
 309                 goto success;
 310         }
 311
 312         /* Save source and destination addresses */
 313         skb_copy_from_linear_data(skb, dest, ETH_ALEN);
 314         skb_copy_from_linear_data_offset(skb, ETH_ALEN, src, ETH_ALEN);
 315
 316         if (host_encrypt || host_build_iv)
 317                 fc = IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA |
 318                     IEEE80211_FCTL_PROTECTED;
 319         else
 320                 fc = IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA;
 321
 322         if (ieee->iw_mode == IW_MODE_INFRA) {
 323                 fc |= IEEE80211_FCTL_TODS;
 324                 /* To DS: Addr1 = BSSID, Addr2 = SA, Addr3 = DA */
 325                 memcpy(header.addr1, ieee->bssid, ETH_ALEN);
 326                 memcpy(header.addr2, src, ETH_ALEN);
 327                 memcpy(header.addr3, dest, ETH_ALEN);
 328         } else if (ieee->iw_mode == IW_MODE_ADHOC) {
 329                 /* not From/To DS: Addr1 = DA, Addr2 = SA, Addr3 = BSSID */
 330                 memcpy(header.addr1, dest, ETH_ALEN);
 331                 memcpy(header.addr2, src, ETH_ALEN);
 332                 memcpy(header.addr3, ieee->bssid, ETH_ALEN);
 333         }
 334         hdr_len = LIBIPW_3ADDR_LEN;
 335
 336         if (ieee->is_qos_active && ieee->is_qos_active(dev, skb)) {
 337                 fc |= IEEE80211_STYPE_QOS_DATA;
 338                 hdr_len += 2;
 339
 340                 skb->priority = libipw_classify(skb);
 341                 header.qos_ctl |= cpu_to_le16(skb->priority & LIBIPW_QCTL_TID);
 342         }
 343         header.frame_ctl = cpu_to_le16(fc);
 344
 345         /* Advance the SKB to the start of the payload */
 346         skb_pull(skb, sizeof(struct ethhdr));
 347
 348         /* Determine total amount of storage required for TXB packets */
 349         bytes = skb->len + SNAP_SIZE + sizeof(u16);
 350
 351         /* Encrypt msdu first on the whole data packet. */
 352         if ((host_encrypt || host_encrypt_msdu) &&
 353             crypt && crypt->ops && crypt->ops->encrypt_msdu) {
 354                 int res = 0;
 355                 int len = bytes + hdr_len + crypt->ops->extra_msdu_prefix_len +
 356                     crypt->ops->extra_msdu_postfix_len;
 357                 struct sk_buff *skb_new = dev_alloc_skb(len);
 358
 359                 if (unlikely(!skb_new))
 360                         goto failed;
 361
 362                 skb_reserve(skb_new, crypt->ops->extra_msdu_prefix_len);
 363                 memcpy(skb_put(skb_new, hdr_len), &header, hdr_len);
 364                 snapped = 1;
 365                 libipw_copy_snap(skb_put(skb_new, SNAP_SIZE + sizeof(u16)),
 366                                     ether_type);
 367                 skb_copy_from_linear_data(skb, skb_put(skb_new, skb->len), skb->len);
 368                 res = crypt->ops->encrypt_msdu(skb_new, hdr_len, crypt->priv);
 369                 if (res < 0) {
 370                         LIBIPW_ERROR("msdu encryption failed\n");
 371                         dev_kfree_skb_any(skb_new);
 372                         goto failed;
 373                 }
 374                 dev_kfree_skb_any(skb);
 375                 skb = skb_new;
 376                 bytes += crypt->ops->extra_msdu_prefix_len +
 377                     crypt->ops->extra_msdu_postfix_len;
 378                 skb_pull(skb, hdr_len);
 379         }
 380
 381         if (host_encrypt || ieee->host_open_frag) {
 382                 /* Determine fragmentation size based on destination (multicast
 383                  * and broadcast are not fragmented) */
 384                 if (is_multicast_ether_addr(dest) ||
 385                     is_broadcast_ether_addr(dest))
 386                         frag_size = MAX_FRAG_THRESHOLD;
 387                 else
 388                         frag_size = ieee->fts;
 389
 390                 /* Determine amount of payload per fragment.  Regardless of if
 391                  * this stack is providing the full 802.11 header, one will
 392                  * eventually be affixed to this fragment -- so we must account
 393                  * for it when determining the amount of payload space. */
 394                 bytes_per_frag = frag_size - hdr_len;
 395                 if (ieee->config &
 396                     (CFG_LIBIPW_COMPUTE_FCS | CFG_LIBIPW_RESERVE_FCS))
 397                         bytes_per_frag -= LIBIPW_FCS_LEN;
 398
 399                 /* Each fragment may need to have room for encryptiong
 400                  * pre/postfix */
 401                 if (host_encrypt)
 402                         bytes_per_frag -= crypt->ops->extra_mpdu_prefix_len +
 403                             crypt->ops->extra_mpdu_postfix_len;
 404
 405                 /* Number of fragments is the total
 406                  * bytes_per_frag / payload_per_fragment */
 407                 nr_frags = bytes / bytes_per_frag;
 408                 bytes_last_frag = bytes % bytes_per_frag;
 409                 if (bytes_last_frag)
 410                         nr_frags++;
 411                 else
 412                         bytes_last_frag = bytes_per_frag;
 413         } else {
 414                 nr_frags = 1;
 415                 bytes_per_frag = bytes_last_frag = bytes;
 416                 frag_size = bytes + hdr_len;
 417         }
 418
 419         rts_required = (frag_size > ieee->rts
 420                         && ieee->config & CFG_LIBIPW_RTS);
 421         if (rts_required)
 422                 nr_frags++;
 423
 424         /* When we allocate the TXB we allocate enough space for the reserve
 425          * and full fragment bytes (bytes_per_frag doesn't include prefix,
 426          * postfix, header, FCS, etc.) */
 427         txb = libipw_alloc_txb(nr_frags, frag_size,
 428                                   ieee->tx_headroom, GFP_ATOMIC);
 429         if (unlikely(!txb)) {
 430                 printk(KERN_WARNING "%s: Could not allocate TXB\n",
 431                        ieee->dev->name);
 432                 goto failed;
 433         }
 434         txb->encrypted = encrypt;
 435         if (host_encrypt)
 436                 txb->payload_size = frag_size * (nr_frags - 1) +
 437                     bytes_last_frag;
 438         else
 439                 txb->payload_size = bytes;
 440
 441         if (rts_required) {
 442                 skb_frag = txb->fragments[0];
 443                 frag_hdr =
 444                     (struct libipw_hdr_3addrqos *)skb_put(skb_frag, hdr_len);
 445
 446                 /*
 447                  * Set header frame_ctl to the RTS.
 448                  */
 449                 header.frame_ctl =
 450                     cpu_to_le16(IEEE80211_FTYPE_CTL | IEEE80211_STYPE_RTS);
 451                 memcpy(frag_hdr, &header, hdr_len);
 452
 453                 /*
 454                  * Restore header frame_ctl to the original data setting.
 455                  */
 456                 header.frame_ctl = cpu_to_le16(fc);
 457
 458                 if (ieee->config &
 459                     (CFG_LIBIPW_COMPUTE_FCS | CFG_LIBIPW_RESERVE_FCS))
 460                         skb_put(skb_frag, 4);
 461
 462                 txb->rts_included = 1;
 463                 i = 1;
 464         } else
 465                 i = 0;
 466
 467         for (; i < nr_frags; i++) {
 468                 skb_frag = txb->fragments[i];
 469
 470                 if (host_encrypt || host_build_iv)
 471                         skb_reserve(skb_frag,
 472                                     crypt->ops->extra_mpdu_prefix_len);
 473
 474                 frag_hdr =
 475                     (struct libipw_hdr_3addrqos *)skb_put(skb_frag, hdr_len);
 476                 memcpy(frag_hdr, &header, hdr_len);
 477
 478                 /* If this is not the last fragment, then add the MOREFRAGS
 479                  * bit to the frame control */
 480                 if (i != nr_frags - 1) {
 481                         frag_hdr->frame_ctl =
 482                             cpu_to_le16(fc | IEEE80211_FCTL_MOREFRAGS);
 483                         bytes = bytes_per_frag;
 484                 } else {
 485                         /* The last fragment takes the remaining length */
 486                         bytes = bytes_last_frag;
 487                 }
 488
 489                 if (i == 0 && !snapped) {
 490                         libipw_copy_snap(skb_put
 491                                             (skb_frag, SNAP_SIZE + sizeof(u16)),
 492                                             ether_type);
 493                         bytes -= SNAP_SIZE + sizeof(u16);
 494                 }
 495
 496                 skb_copy_from_linear_data(skb, skb_put(skb_frag, bytes), bytes);
 497
 498                 /* Advance the SKB... */
 499                 skb_pull(skb, bytes);
 500
 501                 /* Encryption routine will move the header forward in order
 502                  * to insert the IV between the header and the payload */
 503                 if (host_encrypt)
 504                         libipw_encrypt_fragment(ieee, skb_frag, hdr_len);
 505                 else if (host_build_iv) {
 506                         atomic_inc(&crypt->refcnt);
 507                         if (crypt->ops->build_iv)
 508                                 crypt->ops->build_iv(skb_frag, hdr_len,
 509                                       ieee->sec.keys[ieee->sec.active_key],
 510                                       ieee->sec.key_sizes[ieee->sec.active_key],
 511                                       crypt->priv);
 512                         atomic_dec(&crypt->refcnt);
 513                 }
 514
 515                 if (ieee->config &
 516                     (CFG_LIBIPW_COMPUTE_FCS | CFG_LIBIPW_RESERVE_FCS))
 517                         skb_put(skb_frag, 4);
 518         }
 519
 520       success:
 521         spin_unlock_irqrestore(&ieee->lock, flags);
 522
 523         dev_kfree_skb_any(skb);
 524
 525         if (txb) {
 526                 netdev_tx_t ret = (*ieee->hard_start_xmit)(txb, dev, priority);
 527                 if (ret == NETDEV_TX_OK) {
 528                         dev->stats.tx_packets++;
 529                         dev->stats.tx_bytes += txb->payload_size;
 530                         return NETDEV_TX_OK;
 531                 }
 532
 533                 libipw_txb_free(txb);
 534         }
 535
 536         return NETDEV_TX_OK;
 537
 538       failed:
 539         spin_unlock_irqrestore(&ieee->lock, flags);
 540         netif_stop_queue(dev);
 541         dev->stats.tx_errors++;
 542         return NETDEV_TX_BUSY;
 543 }
 544 EXPORT_SYMBOL(libipw_xmit);
 545
 546 EXPORT_SYMBOL(libipw_txb_free);