drivers/staging/wlan-ng/p80211conv.c

   1 /* src/p80211/p80211conv.c
   2 *
   3 * Ether/802.11 conversions and packet buffer routines
   4 *
   5 * Copyright (C) 1999 AbsoluteValue Systems, Inc.  All Rights Reserved.
   6 * --------------------------------------------------------------------
   7 *
   8 * linux-wlan
   9 *
  10 *   The contents of this file are subject to the Mozilla Public
  11 *   License Version 1.1 (the "License"); you may not use this file
  12 *   except in compliance with the License. You may obtain a copy of
  13 *   the License at http://www.mozilla.org/MPL/
  14 *
  15 *   Software distributed under the License is distributed on an "AS
  16 *   IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
  17 *   implied. See the License for the specific language governing
  18 *   rights and limitations under the License.
  19 *
  20 *   Alternatively, the contents of this file may be used under the
  21 *   terms of the GNU Public License version 2 (the "GPL"), in which
  22 *   case the provisions of the GPL are applicable instead of the
  23 *   above.  If you wish to allow the use of your version of this file
  24 *   only under the terms of the GPL and not to allow others to use
  25 *   your version of this file under the MPL, indicate your decision
  26 *   by deleting the provisions above and replace them with the notice
  27 *   and other provisions required by the GPL.  If you do not delete
  28 *   the provisions above, a recipient may use your version of this
  29 *   file under either the MPL or the GPL.
  30 *
  31 * --------------------------------------------------------------------
  32 *
  33 * Inquiries regarding the linux-wlan Open Source project can be
  34 * made directly to:
  35 *
  36 * AbsoluteValue Systems Inc.
  37 * info@linux-wlan.com
  38 * http://www.linux-wlan.com
  39 *
  40 * --------------------------------------------------------------------
  41 *
  42 * Portions of the development of this software were funded by
  43 * Intersil Corporation as part of PRISM(R) chipset product development.
  44 *
  45 * --------------------------------------------------------------------
  46 *
  47 * This file defines the functions that perform Ethernet to/from
  48 * 802.11 frame conversions.
  49 *
  50 * --------------------------------------------------------------------
  51 *
  52 *================================================================ */
  53
  54 #include <linux/module.h>
  55 #include <linux/kernel.h>
  56 #include <linux/sched.h>
  57 #include <linux/types.h>
  58 #include <linux/skbuff.h>
  59 #include <linux/slab.h>
  60 #include <linux/wireless.h>
  61 #include <linux/netdevice.h>
  62 #include <linux/etherdevice.h>
  63 #include <linux/if_ether.h>
  64 #include <linux/byteorder/generic.h>
  65
  66 #include <asm/byteorder.h>
  67
  68 #include "p80211types.h"
  69 #include "p80211hdr.h"
  70 #include "p80211conv.h"
  71 #include "p80211mgmt.h"
  72 #include "p80211msg.h"
  73 #include "p80211netdev.h"
  74 #include "p80211ioctl.h"
  75 #include "p80211req.h"
  76
  77 static u8 oui_rfc1042[] = { 0x00, 0x00, 0x00 };
  78 static u8 oui_8021h[] = { 0x00, 0x00, 0xf8 };
  79
  80 /*----------------------------------------------------------------
  81 * p80211pb_ether_to_80211
  82 *
  83 * Uses the contents of the ether frame and the etherconv setting
  84 * to build the elements of the 802.11 frame.
  85 *
  86 * We don't actually set
  87 * up the frame header here.  That's the MAC's job.  We're only handling
  88 * conversion of DIXII or 802.3+LLC frames to something that works
  89 * with 802.11.
  90 *
  91 * Note -- 802.11 header is NOT part of the skb.  Likewise, the 802.11
  92 *         FCS is also not present and will need to be added elsewhere.
  93 *
  94 * Arguments:
  95 *       ethconv         Conversion type to perform
  96 *       skb             skbuff containing the ether frame
  97 *       p80211_hdr      802.11 header
  98 *
  99 * Returns:
 100 *       0 on success, non-zero otherwise
 101 *
 102 * Call context:
 103 *       May be called in interrupt or non-interrupt context
 104 ----------------------------------------------------------------*/
 105 int skb_ether_to_p80211(wlandevice_t *wlandev, u32 ethconv,
 106                         struct sk_buff *skb, union p80211_hdr *p80211_hdr,
 107                         struct p80211_metawep *p80211_wep)
 108 {
 109
 110         __le16 fc;
 111         u16 proto;
 112         struct wlan_ethhdr e_hdr;
 113         struct wlan_llc *e_llc;
 114         struct wlan_snap *e_snap;
 115         int foo;
 116
 117         memcpy(&e_hdr, skb->data, sizeof(e_hdr));
 118
 119         if (skb->len <= 0) {
 120                 pr_debug("zero-length skb!\n");
 121                 return 1;
 122         }
 123
 124         if (ethconv == WLAN_ETHCONV_ENCAP) {    /* simplest case */
 125                 pr_debug("ENCAP len: %d\n", skb->len);
 126                 /* here, we don't care what kind of ether frm. Just stick it */
 127                 /*  in the 80211 payload */
 128                 /* which is to say, leave the skb alone. */
 129         } else {
 130                 /* step 1: classify ether frame, DIX or 802.3? */
 131                 proto = ntohs(e_hdr.type);
 132                 if (proto <= ETH_DATA_LEN) {
 133                         pr_debug("802.3 len: %d\n", skb->len);
 134                         /* codes <= 1500 reserved for 802.3 lengths */
 135                         /* it's 802.3, pass ether payload unchanged,  */
 136
 137                         /* trim off ethernet header */
 138                         skb_pull(skb, ETH_HLEN);
 139
 140                         /*   leave off any PAD octets.  */
 141                         skb_trim(skb, proto);
 142                 } else {
 143                         pr_debug("DIXII len: %d\n", skb->len);
 144                         /* it's DIXII, time for some conversion */
 145
 146                         /* trim off ethernet header */
 147                         skb_pull(skb, ETH_HLEN);
 148
 149                         /* tack on SNAP */
 150                         e_snap =
 151                             (struct wlan_snap *) skb_push(skb,
 152                                 sizeof(struct wlan_snap));
 153                         e_snap->type = htons(proto);
 154                         if (ethconv == WLAN_ETHCONV_8021h
 155                             && p80211_stt_findproto(proto)) {
 156                                 memcpy(e_snap->oui, oui_8021h,
 157                                        WLAN_IEEE_OUI_LEN);
 158                         } else {
 159                                 memcpy(e_snap->oui, oui_rfc1042,
 160                                        WLAN_IEEE_OUI_LEN);
 161                         }
 162
 163                         /* tack on llc */
 164                         e_llc =
 165                             (struct wlan_llc *) skb_push(skb,
 166                                 sizeof(struct wlan_llc));
 167                         e_llc->dsap = 0xAA;     /* SNAP, see IEEE 802 */
 168                         e_llc->ssap = 0xAA;
 169                         e_llc->ctl = 0x03;
 170
 171                 }
 172         }
 173
 174         /* Set up the 802.11 header */
 175         /* It's a data frame */
 176         fc = cpu_to_le16(WLAN_SET_FC_FTYPE(WLAN_FTYPE_DATA) |
 177                          WLAN_SET_FC_FSTYPE(WLAN_FSTYPE_DATAONLY));
 178
 179         switch (wlandev->macmode) {
 180         case WLAN_MACMODE_IBSS_STA:
 181                 memcpy(p80211_hdr->a3.a1, &e_hdr.daddr, ETH_ALEN);
 182                 memcpy(p80211_hdr->a3.a2, wlandev->netdev->dev_addr, ETH_ALEN);
 183                 memcpy(p80211_hdr->a3.a3, wlandev->bssid, ETH_ALEN);
 184                 break;
 185         case WLAN_MACMODE_ESS_STA:
 186                 fc |= cpu_to_le16(WLAN_SET_FC_TODS(1));
 187                 memcpy(p80211_hdr->a3.a1, wlandev->bssid, ETH_ALEN);
 188                 memcpy(p80211_hdr->a3.a2, wlandev->netdev->dev_addr, ETH_ALEN);
 189                 memcpy(p80211_hdr->a3.a3, &e_hdr.daddr, ETH_ALEN);
 190                 break;
 191         case WLAN_MACMODE_ESS_AP:
 192                 fc |= cpu_to_le16(WLAN_SET_FC_FROMDS(1));
 193                 memcpy(p80211_hdr->a3.a1, &e_hdr.daddr, ETH_ALEN);
 194                 memcpy(p80211_hdr->a3.a2, wlandev->bssid, ETH_ALEN);
 195                 memcpy(p80211_hdr->a3.a3, &e_hdr.saddr, ETH_ALEN);
 196                 break;
 197         default:
 198                 netdev_err(wlandev->netdev,
 199                            "Error: Converting eth to wlan in unknown mode.\n");
 200                 return 1;
 201         }
 202
 203         p80211_wep->data = NULL;
 204
 205         if ((wlandev->hostwep & HOSTWEP_PRIVACYINVOKED)
 206             && (wlandev->hostwep & HOSTWEP_ENCRYPT)) {
 207                 /* XXXX need to pick keynum other than default? */
 208
 209                 p80211_wep->data = kmalloc(skb->len, GFP_ATOMIC);
 210                 if (!p80211_wep->data)
 211                         return -ENOMEM;
 212                 foo = wep_encrypt(wlandev, skb->data, p80211_wep->data,
 213                                   skb->len,
 214                                   (wlandev->hostwep & HOSTWEP_DEFAULTKEY_MASK),
 215                                   p80211_wep->iv, p80211_wep->icv);
 216                 if (foo) {
 217                         netdev_warn(wlandev->netdev,
 218                                "Host en-WEP failed, dropping frame (%d).\n",
 219                                foo);
 220                         return 2;
 221                 }
 222                 fc |= cpu_to_le16(WLAN_SET_FC_ISWEP(1));
 223         }
 224
 225         /*      skb->nh.raw = skb->data; */
 226
 227         p80211_hdr->a3.fc = fc;
 228         p80211_hdr->a3.dur = 0;
 229         p80211_hdr->a3.seq = 0;
 230
 231         return 0;
 232 }
 233
 234 /* jkriegl: from orinoco, modified */
 235 static void orinoco_spy_gather(wlandevice_t *wlandev, char *mac,
 236                                struct p80211_rxmeta *rxmeta)
 237 {
 238         int i;
 239
 240         /* Gather wireless spy statistics: for each packet, compare the
 241          * source address with out list, and if match, get the stats... */
 242
 243         for (i = 0; i < wlandev->spy_number; i++) {
 244
 245                 if (!memcmp(wlandev->spy_address[i], mac, ETH_ALEN)) {
 246                         memcpy(wlandev->spy_address[i], mac, ETH_ALEN);
 247                         wlandev->spy_stat[i].level = rxmeta->signal;
 248                         wlandev->spy_stat[i].noise = rxmeta->noise;
 249                         wlandev->spy_stat[i].qual =
 250                             (rxmeta->signal >
 251                              rxmeta->noise) ? (rxmeta->signal -
 252                                                rxmeta->noise) : 0;
 253                         wlandev->spy_stat[i].updated = 0x7;
 254                 }
 255         }
 256 }
 257
 258 /*----------------------------------------------------------------
 259 * p80211pb_80211_to_ether
 260 *
 261 * Uses the contents of a received 802.11 frame and the etherconv
 262 * setting to build an ether frame.
 263 *
 264 * This function extracts the src and dest address from the 802.11
 265 * frame to use in the construction of the eth frame.
 266 *
 267 * Arguments:
 268 *       ethconv         Conversion type to perform
 269 *       skb             Packet buffer containing the 802.11 frame
 270 *
 271 * Returns:
 272 *       0 on success, non-zero otherwise
 273 *
 274 * Call context:
 275 *       May be called in interrupt or non-interrupt context
 276 ----------------------------------------------------------------*/
 277 int skb_p80211_to_ether(wlandevice_t *wlandev, u32 ethconv,
 278                         struct sk_buff *skb)
 279 {
 280         netdevice_t *netdev = wlandev->netdev;
 281         u16 fc;
 282         unsigned int payload_length;
 283         unsigned int payload_offset;
 284         u8 daddr[ETH_ALEN];
 285         u8 saddr[ETH_ALEN];
 286         union p80211_hdr *w_hdr;
 287         struct wlan_ethhdr *e_hdr;
 288         struct wlan_llc *e_llc;
 289         struct wlan_snap *e_snap;
 290
 291         int foo;
 292
 293         payload_length = skb->len - WLAN_HDR_A3_LEN - WLAN_CRC_LEN;
 294         payload_offset = WLAN_HDR_A3_LEN;
 295
 296         w_hdr = (union p80211_hdr *) skb->data;
 297
 298         /* setup some vars for convenience */
 299         fc = le16_to_cpu(w_hdr->a3.fc);
 300         if ((WLAN_GET_FC_TODS(fc) == 0) && (WLAN_GET_FC_FROMDS(fc) == 0)) {
 301                 ether_addr_copy(daddr, w_hdr->a3.a1);
 302                 ether_addr_copy(saddr, w_hdr->a3.a2);
 303         } else if ((WLAN_GET_FC_TODS(fc) == 0)
 304                         && (WLAN_GET_FC_FROMDS(fc) == 1)) {
 305                 ether_addr_copy(daddr, w_hdr->a3.a1);
 306                 ether_addr_copy(saddr, w_hdr->a3.a3);
 307         } else if ((WLAN_GET_FC_TODS(fc) == 1)
 308                         && (WLAN_GET_FC_FROMDS(fc) == 0)) {
 309                 ether_addr_copy(daddr, w_hdr->a3.a3);
 310                 ether_addr_copy(saddr, w_hdr->a3.a2);
 311         } else {
 312                 payload_offset = WLAN_HDR_A4_LEN;
 313                 if (payload_length < WLAN_HDR_A4_LEN - WLAN_HDR_A3_LEN) {
 314                         netdev_err(netdev, "A4 frame too short!\n");
 315                         return 1;
 316                 }
 317                 payload_length -= (WLAN_HDR_A4_LEN - WLAN_HDR_A3_LEN);
 318                 ether_addr_copy(daddr, w_hdr->a4.a3);
 319                 ether_addr_copy(saddr, w_hdr->a4.a4);
 320         }
 321
 322         /* perform de-wep if necessary.. */
 323         if ((wlandev->hostwep & HOSTWEP_PRIVACYINVOKED) && WLAN_GET_FC_ISWEP(fc)
 324             && (wlandev->hostwep & HOSTWEP_DECRYPT)) {
 325                 if (payload_length <= 8) {
 326                         netdev_err(netdev,
 327                                    "WEP frame too short (%u).\n", skb->len);
 328                         return 1;
 329                 }
 330                 foo = wep_decrypt(wlandev, skb->data + payload_offset + 4,
 331                                        payload_length - 8, -1,
 332                                        skb->data + payload_offset,
 333                                        skb->data + payload_offset +
 334                                        payload_length - 4);
 335                 if (foo) {
 336                         /* de-wep failed, drop skb. */
 337                         pr_debug("Host de-WEP failed, dropping frame (%d).\n",
 338                                  foo);
 339                         wlandev->rx.decrypt_err++;
 340                         return 2;
 341                 }
 342
 343                 /* subtract the IV+ICV length off the payload */
 344                 payload_length -= 8;
 345                 /* chop off the IV */
 346                 skb_pull(skb, 4);
 347                 /* chop off the ICV. */
 348                 skb_trim(skb, skb->len - 4);
 349
 350                 wlandev->rx.decrypt++;
 351         }
 352
 353         e_hdr = (struct wlan_ethhdr *) (skb->data + payload_offset);
 354
 355         e_llc = (struct wlan_llc *) (skb->data + payload_offset);
 356         e_snap =
 357             (struct wlan_snap *) (skb->data + payload_offset +
 358                 sizeof(struct wlan_llc));
 359
 360         /* Test for the various encodings */
 361         if ((payload_length >= sizeof(struct wlan_ethhdr)) &&
 362             (e_llc->dsap != 0xaa || e_llc->ssap != 0xaa) &&
 363             ((!ether_addr_equal_unaligned(daddr, e_hdr->daddr)) ||
 364              (!ether_addr_equal_unaligned(saddr, e_hdr->saddr)))) {
 365                 pr_debug("802.3 ENCAP len: %d\n", payload_length);
 366                 /* 802.3 Encapsulated */
 367                 /* Test for an overlength frame */
 368                 if (payload_length > (netdev->mtu + ETH_HLEN)) {
 369                         /* A bogus length ethfrm has been encap'd. */
 370                         /* Is someone trying an oflow attack? */
 371                         netdev_err(netdev, "ENCAP frame too large (%d > %d)\n",
 372                                payload_length, netdev->mtu + ETH_HLEN);
 373                         return 1;
 374                 }
 375
 376                 /* Chop off the 802.11 header.  it's already sane. */
 377                 skb_pull(skb, payload_offset);
 378                 /* chop off the 802.11 CRC */
 379                 skb_trim(skb, skb->len - WLAN_CRC_LEN);
 380
 381         } else if ((payload_length >= sizeof(struct wlan_llc) +
 382                 sizeof(struct wlan_snap))
 383                 && (e_llc->dsap == 0xaa)
 384                 && (e_llc->ssap == 0xaa)
 385                 && (e_llc->ctl == 0x03)
 386                    &&
 387                    (((memcmp(e_snap->oui, oui_rfc1042, WLAN_IEEE_OUI_LEN) == 0)
 388                      && (ethconv == WLAN_ETHCONV_8021h)
 389                      && (p80211_stt_findproto(le16_to_cpu(e_snap->type))))
 390                     || (memcmp(e_snap->oui, oui_rfc1042, WLAN_IEEE_OUI_LEN) !=
 391                         0))) {
 392                 pr_debug("SNAP+RFC1042 len: %d\n", payload_length);
 393                 /* it's a SNAP + RFC1042 frame && protocol is in STT */
 394                 /* build 802.3 + RFC1042 */
 395
 396                 /* Test for an overlength frame */
 397                 if (payload_length > netdev->mtu) {
 398                         /* A bogus length ethfrm has been sent. */
 399                         /* Is someone trying an oflow attack? */
 400                         netdev_err(netdev, "SNAP frame too large (%d > %d)\n",
 401                                payload_length, netdev->mtu);
 402                         return 1;
 403                 }
 404
 405                 /* chop 802.11 header from skb. */
 406                 skb_pull(skb, payload_offset);
 407
 408                 /* create 802.3 header at beginning of skb. */
 409                 e_hdr = (struct wlan_ethhdr *)skb_push(skb, ETH_HLEN);
 410                 ether_addr_copy(e_hdr->daddr, daddr);
 411                 ether_addr_copy(e_hdr->saddr, saddr);
 412                 e_hdr->type = htons(payload_length);
 413
 414                 /* chop off the 802.11 CRC */
 415                 skb_trim(skb, skb->len - WLAN_CRC_LEN);
 416
 417         } else if ((payload_length >= sizeof(struct wlan_llc) +
 418                 sizeof(struct wlan_snap))
 419                 && (e_llc->dsap == 0xaa)
 420                 && (e_llc->ssap == 0xaa)
 421                 && (e_llc->ctl == 0x03)) {
 422                 pr_debug("802.1h/RFC1042 len: %d\n", payload_length);
 423                 /* it's an 802.1h frame || (an RFC1042 && protocol not in STT)
 424                    build a DIXII + RFC894 */
 425
 426                 /* Test for an overlength frame */
 427                 if ((payload_length - sizeof(struct wlan_llc) -
 428                         sizeof(struct wlan_snap))
 429                         > netdev->mtu) {
 430                         /* A bogus length ethfrm has been sent. */
 431                         /* Is someone trying an oflow attack? */
 432                         netdev_err(netdev, "DIXII frame too large (%ld > %d)\n",
 433                                (long int)(payload_length -
 434                                         sizeof(struct wlan_llc) -
 435                                         sizeof(struct wlan_snap)), netdev->mtu);
 436                         return 1;
 437                 }
 438
 439                 /* chop 802.11 header from skb. */
 440                 skb_pull(skb, payload_offset);
 441
 442                 /* chop llc header from skb. */
 443                 skb_pull(skb, sizeof(struct wlan_llc));
 444
 445                 /* chop snap header from skb. */
 446                 skb_pull(skb, sizeof(struct wlan_snap));
 447
 448                 /* create 802.3 header at beginning of skb. */
 449                 e_hdr = (struct wlan_ethhdr *)skb_push(skb, ETH_HLEN);
 450                 e_hdr->type = e_snap->type;
 451                 ether_addr_copy(e_hdr->daddr, daddr);
 452                 ether_addr_copy(e_hdr->saddr, saddr);
 453
 454                 /* chop off the 802.11 CRC */
 455                 skb_trim(skb, skb->len - WLAN_CRC_LEN);
 456         } else {
 457                 pr_debug("NON-ENCAP len: %d\n", payload_length);
 458                 /* any NON-ENCAP */
 459                 /* it's a generic 80211+LLC or IPX 'Raw 802.3' */
 460                 /*  build an 802.3 frame */
 461                 /* allocate space and setup hostbuf */
 462
 463                 /* Test for an overlength frame */
 464                 if (payload_length > netdev->mtu) {
 465                         /* A bogus length ethfrm has been sent. */
 466                         /* Is someone trying an oflow attack? */
 467                         netdev_err(netdev, "OTHER frame too large (%d > %d)\n",
 468                                payload_length, netdev->mtu);
 469                         return 1;
 470                 }
 471
 472                 /* Chop off the 802.11 header. */
 473                 skb_pull(skb, payload_offset);
 474
 475                 /* create 802.3 header at beginning of skb. */
 476                 e_hdr = (struct wlan_ethhdr *)skb_push(skb, ETH_HLEN);
 477                 ether_addr_copy(e_hdr->daddr, daddr);
 478                 ether_addr_copy(e_hdr->saddr, saddr);
 479                 e_hdr->type = htons(payload_length);
 480
 481                 /* chop off the 802.11 CRC */
 482                 skb_trim(skb, skb->len - WLAN_CRC_LEN);
 483
 484         }
 485
 486         /*
 487          * Note that eth_type_trans() expects an skb w/ skb->data pointing
 488          * at the MAC header, it then sets the following skb members:
 489          * skb->mac_header,
 490          * skb->data, and
 491          * skb->pkt_type.
 492          * It then _returns_ the value that _we're_ supposed to stuff in
 493          * skb->protocol.  This is nuts.
 494          */
 495         skb->protocol = eth_type_trans(skb, netdev);
 496
 497         /* jkriegl: process signal and noise as set in hfa384x_int_rx() */
 498         /* jkriegl: only process signal/noise if requested by iwspy */
 499         if (wlandev->spy_number)
 500                 orinoco_spy_gather(wlandev, eth_hdr(skb)->h_source,
 501                                    P80211SKB_RXMETA(skb));
 502
 503         /* Free the metadata */
 504         p80211skb_rxmeta_detach(skb);
 505
 506         return 0;
 507 }
 508
 509 /*----------------------------------------------------------------
 510 * p80211_stt_findproto
 511 *
 512 * Searches the 802.1h Selective Translation Table for a given
 513 * protocol.
 514 *
 515 * Arguments:
 516 *       proto   protocol number (in host order) to search for.
 517 *
 518 * Returns:
 519 *       1 - if the table is empty or a match is found.
 520 *       0 - if the table is non-empty and a match is not found.
 521 *
 522 * Call context:
 523 *       May be called in interrupt or non-interrupt context
 524 ----------------------------------------------------------------*/
 525 int p80211_stt_findproto(u16 proto)
 526 {
 527         /* Always return found for now.  This is the behavior used by the */
 528         /*  Zoom Win95 driver when 802.1h mode is selected */
 529         /* TODO: If necessary, add an actual search we'll probably
 530            need this to match the CMAC's way of doing things.
 531            Need to do some testing to confirm.
 532          */
 533
 534         if (proto == ETH_P_AARP)        /* APPLETALK */
 535                 return 1;
 536
 537         return 0;
 538 }
 539
 540 /*----------------------------------------------------------------
 541 * p80211skb_rxmeta_detach
 542 *
 543 * Disconnects the frmmeta and rxmeta from an skb.
 544 *
 545 * Arguments:
 546 *       wlandev         The wlandev this skb belongs to.
 547 *       skb             The skb we're attaching to.
 548 *
 549 * Returns:
 550 *       0 on success, non-zero otherwise
 551 *
 552 * Call context:
 553 *       May be called in interrupt or non-interrupt context
 554 ----------------------------------------------------------------*/
 555 void p80211skb_rxmeta_detach(struct sk_buff *skb)
 556 {
 557         struct p80211_rxmeta *rxmeta;
 558         struct p80211_frmmeta *frmmeta;
 559
 560         /* Sanity checks */
 561         if (skb == NULL) {      /* bad skb */
 562                 pr_debug("Called w/ null skb.\n");
 563                 return;
 564         }
 565         frmmeta = P80211SKB_FRMMETA(skb);
 566         if (frmmeta == NULL) {  /* no magic */
 567                 pr_debug("Called w/ bad frmmeta magic.\n");
 568                 return;
 569         }
 570         rxmeta = frmmeta->rx;
 571         if (rxmeta == NULL) {   /* bad meta ptr */
 572                 pr_debug("Called w/ bad rxmeta ptr.\n");
 573                 return;
 574         }
 575
 576         /* Free rxmeta */
 577         kfree(rxmeta);
 578
 579         /* Clear skb->cb */
 580         memset(skb->cb, 0, sizeof(skb->cb));
 581 }
 582
 583 /*----------------------------------------------------------------
 584 * p80211skb_rxmeta_attach
 585 *
 586 * Allocates a p80211rxmeta structure, initializes it, and attaches
 587 * it to an skb.
 588 *
 589 * Arguments:
 590 *       wlandev         The wlandev this skb belongs to.
 591 *       skb             The skb we're attaching to.
 592 *
 593 * Returns:
 594 *       0 on success, non-zero otherwise
 595 *
 596 * Call context:
 597 *       May be called in interrupt or non-interrupt context
 598 ----------------------------------------------------------------*/
 599 int p80211skb_rxmeta_attach(struct wlandevice *wlandev, struct sk_buff *skb)
 600 {
 601         int result = 0;
 602         struct p80211_rxmeta *rxmeta;
 603         struct p80211_frmmeta *frmmeta;
 604
 605         /* If these already have metadata, we error out! */
 606         if (P80211SKB_RXMETA(skb) != NULL) {
 607                 netdev_err(wlandev->netdev,
 608                            "%s: RXmeta already attached!\n", wlandev->name);
 609                 result = 0;
 610                 goto exit;
 611         }
 612
 613         /* Allocate the rxmeta */
 614         rxmeta = kzalloc(sizeof(struct p80211_rxmeta), GFP_ATOMIC);
 615
 616         if (rxmeta == NULL) {
 617                 netdev_err(wlandev->netdev,
 618                            "%s: Failed to allocate rxmeta.\n", wlandev->name);
 619                 result = 1;
 620                 goto exit;
 621         }
 622
 623         /* Initialize the rxmeta */
 624         rxmeta->wlandev = wlandev;
 625         rxmeta->hosttime = jiffies;
 626
 627         /* Overlay a frmmeta_t onto skb->cb */
 628         memset(skb->cb, 0, sizeof(struct p80211_frmmeta));
 629         frmmeta = (struct p80211_frmmeta *) (skb->cb);
 630         frmmeta->magic = P80211_FRMMETA_MAGIC;
 631         frmmeta->rx = rxmeta;
 632 exit:
 633         return result;
 634 }
 635
 636 /*----------------------------------------------------------------
 637 * p80211skb_free
 638 *
 639 * Frees an entire p80211skb by checking and freeing the meta struct
 640 * and then freeing the skb.
 641 *
 642 * Arguments:
 643 *       wlandev         The wlandev this skb belongs to.
 644 *       skb             The skb we're attaching to.
 645 *
 646 * Returns:
 647 *       0 on success, non-zero otherwise
 648 *
 649 * Call context:
 650 *       May be called in interrupt or non-interrupt context
 651 ----------------------------------------------------------------*/
 652 void p80211skb_free(struct wlandevice *wlandev, struct sk_buff *skb)
 653 {
 654         struct p80211_frmmeta *meta;
 655
 656         meta = P80211SKB_FRMMETA(skb);
 657         if (meta && meta->rx)
 658                 p80211skb_rxmeta_detach(skb);
 659         else
 660                 netdev_err(wlandev->netdev,
 661                            "Freeing an skb (%p) w/ no frmmeta.\n", skb);
 662         dev_kfree_skb(skb);
 663 }