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;
 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
 305         if (!encrypt && ieee->ieee802_1x &&
 306             ieee->drop_unencrypted && ether_type != htons(ETH_P_PAE)) {
 307                 dev->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)
 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 = LIBIPW_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 = libipw_classify(skb);
 340                 header.qos_ctl |= cpu_to_le16(skb->priority & LIBIPW_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                 libipw_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                         LIBIPW_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_LIBIPW_COMPUTE_FCS | CFG_LIBIPW_RESERVE_FCS))
 396                         bytes_per_frag -= LIBIPW_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_LIBIPW_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 = libipw_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 libipw_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_LIBIPW_COMPUTE_FCS | CFG_LIBIPW_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)
 470                         skb_reserve(skb_frag,
 471                                     crypt->ops->extra_mpdu_prefix_len);
 472
 473                 frag_hdr =
 474                     (struct libipw_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                         libipw_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                         libipw_encrypt_fragment(ieee, skb_frag, hdr_len);
 504
 505                 if (ieee->config &
 506                     (CFG_LIBIPW_COMPUTE_FCS | CFG_LIBIPW_RESERVE_FCS))
 507                         skb_put(skb_frag, 4);
 508         }
 509
 510       success:
 511         spin_unlock_irqrestore(&ieee->lock, flags);
 512
 513         dev_kfree_skb_any(skb);
 514
 515         if (txb) {
 516                 netdev_tx_t ret = (*ieee->hard_start_xmit)(txb, dev, priority);
 517                 if (ret == NETDEV_TX_OK) {
 518                         dev->stats.tx_packets++;
 519                         dev->stats.tx_bytes += txb->payload_size;
 520                         return NETDEV_TX_OK;
 521                 }
 522
 523                 libipw_txb_free(txb);
 524         }
 525
 526         return NETDEV_TX_OK;
 527
 528       failed:
 529         spin_unlock_irqrestore(&ieee->lock, flags);
 530         netif_stop_queue(dev);
 531         dev->stats.tx_errors++;
 532         return NETDEV_TX_BUSY;
 533 }
 534 EXPORT_SYMBOL(libipw_xmit);
 535
 536 EXPORT_SYMBOL(libipw_txb_free);