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, p80211_hdr_t * p80211_hdr,
 107                         p80211_metawep_t * p80211_wep)
 108 {
 109
 110         u16 fc;
 111         u16 proto;
 112         wlan_ethhdr_t e_hdr;
 113         wlan_llc_t *e_llc;
 114         wlan_snap_t *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 <= 1500) {
 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, WLAN_ETHHDR_LEN);
 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, WLAN_ETHHDR_LEN);
 148
 149                         /* tack on SNAP */
 150                         e_snap =
 151                             (wlan_snap_t *) skb_push(skb, sizeof(wlan_snap_t));
 152                         e_snap->type = htons(proto);
 153                         if (ethconv == WLAN_ETHCONV_8021h
 154                             && p80211_stt_findproto(proto)) {
 155                                 memcpy(e_snap->oui, oui_8021h,
 156                                        WLAN_IEEE_OUI_LEN);
 157                         } else {
 158                                 memcpy(e_snap->oui, oui_rfc1042,
 159                                        WLAN_IEEE_OUI_LEN);
 160                         }
 161
 162                         /* tack on llc */
 163                         e_llc =
 164                             (wlan_llc_t *) skb_push(skb, sizeof(wlan_llc_t));
 165                         e_llc->dsap = 0xAA;     /* SNAP, see IEEE 802 */
 166                         e_llc->ssap = 0xAA;
 167                         e_llc->ctl = 0x03;
 168
 169                 }
 170         }
 171
 172         /* Set up the 802.11 header */
 173         /* It's a data frame */
 174         fc = cpu_to_le16(WLAN_SET_FC_FTYPE(WLAN_FTYPE_DATA) |
 175                          WLAN_SET_FC_FSTYPE(WLAN_FSTYPE_DATAONLY));
 176
 177         switch (wlandev->macmode) {
 178         case WLAN_MACMODE_IBSS_STA:
 179                 memcpy(p80211_hdr->a3.a1, &e_hdr.daddr, ETH_ALEN);
 180                 memcpy(p80211_hdr->a3.a2, wlandev->netdev->dev_addr, ETH_ALEN);
 181                 memcpy(p80211_hdr->a3.a3, wlandev->bssid, ETH_ALEN);
 182                 break;
 183         case WLAN_MACMODE_ESS_STA:
 184                 fc |= cpu_to_le16(WLAN_SET_FC_TODS(1));
 185                 memcpy(p80211_hdr->a3.a1, wlandev->bssid, ETH_ALEN);
 186                 memcpy(p80211_hdr->a3.a2, wlandev->netdev->dev_addr, ETH_ALEN);
 187                 memcpy(p80211_hdr->a3.a3, &e_hdr.daddr, ETH_ALEN);
 188                 break;
 189         case WLAN_MACMODE_ESS_AP:
 190                 fc |= cpu_to_le16(WLAN_SET_FC_FROMDS(1));
 191                 memcpy(p80211_hdr->a3.a1, &e_hdr.daddr, ETH_ALEN);
 192                 memcpy(p80211_hdr->a3.a2, wlandev->bssid, ETH_ALEN);
 193                 memcpy(p80211_hdr->a3.a3, &e_hdr.saddr, ETH_ALEN);
 194                 break;
 195         default:
 196                 printk(KERN_ERR
 197                        "Error: Converting eth to wlan in unknown mode.\n");
 198                 return 1;
 199                 break;
 200         }
 201
 202         p80211_wep->data = NULL;
 203
 204         if ((wlandev->hostwep & HOSTWEP_PRIVACYINVOKED)
 205             && (wlandev->hostwep & HOSTWEP_ENCRYPT)) {
 206                 /* XXXX need to pick keynum other than default? */
 207
 208                 p80211_wep->data = kmalloc(skb->len, GFP_ATOMIC);
 209
 210                 if ((foo = wep_encrypt(wlandev, skb->data, p80211_wep->data,
 211                                        skb->len,
 212                                        (wlandev->hostwep &
 213                                         HOSTWEP_DEFAULTKEY_MASK),
 214                                        p80211_wep->iv, p80211_wep->icv))) {
 215                         printk(KERN_WARNING
 216                                "Host en-WEP failed, dropping frame (%d).\n",
 217                                foo);
 218                         return 2;
 219                 }
 220                 fc |= cpu_to_le16(WLAN_SET_FC_ISWEP(1));
 221         }
 222
 223         /*      skb->nh.raw = skb->data; */
 224
 225         p80211_hdr->a3.fc = fc;
 226         p80211_hdr->a3.dur = 0;
 227         p80211_hdr->a3.seq = 0;
 228
 229         return 0;
 230 }
 231
 232 /* jkriegl: from orinoco, modified */
 233 static void orinoco_spy_gather(wlandevice_t * wlandev, char *mac,
 234                                p80211_rxmeta_t * rxmeta)
 235 {
 236         int i;
 237
 238         /* Gather wireless spy statistics: for each packet, compare the
 239          * source address with out list, and if match, get the stats... */
 240
 241         for (i = 0; i < wlandev->spy_number; i++) {
 242
 243                 if (!memcmp(wlandev->spy_address[i], mac, ETH_ALEN)) {
 244                         memcpy(wlandev->spy_address[i], mac, ETH_ALEN);
 245                         wlandev->spy_stat[i].level = rxmeta->signal;
 246                         wlandev->spy_stat[i].noise = rxmeta->noise;
 247                         wlandev->spy_stat[i].qual =
 248                             (rxmeta->signal >
 249                              rxmeta->noise) ? (rxmeta->signal -
 250                                                rxmeta->noise) : 0;
 251                         wlandev->spy_stat[i].updated = 0x7;
 252                 }
 253         }
 254 }
 255
 256 /*----------------------------------------------------------------
 257 * p80211pb_80211_to_ether
 258 *
 259 * Uses the contents of a received 802.11 frame and the etherconv
 260 * setting to build an ether frame.
 261 *
 262 * This function extracts the src and dest address from the 802.11
 263 * frame to use in the construction of the eth frame.
 264 *
 265 * Arguments:
 266 *       ethconv         Conversion type to perform
 267 *       skb             Packet buffer containing the 802.11 frame
 268 *
 269 * Returns:
 270 *       0 on success, non-zero otherwise
 271 *
 272 * Call context:
 273 *       May be called in interrupt or non-interrupt context
 274 ----------------------------------------------------------------*/
 275 int skb_p80211_to_ether(wlandevice_t * wlandev, u32 ethconv,
 276                         struct sk_buff *skb)
 277 {
 278         netdevice_t *netdev = wlandev->netdev;
 279         u16 fc;
 280         unsigned int payload_length;
 281         unsigned int payload_offset;
 282         u8 daddr[WLAN_ETHADDR_LEN];
 283         u8 saddr[WLAN_ETHADDR_LEN];
 284         p80211_hdr_t *w_hdr;
 285         wlan_ethhdr_t *e_hdr;
 286         wlan_llc_t *e_llc;
 287         wlan_snap_t *e_snap;
 288
 289         int foo;
 290
 291         payload_length = skb->len - WLAN_HDR_A3_LEN - WLAN_CRC_LEN;
 292         payload_offset = WLAN_HDR_A3_LEN;
 293
 294         w_hdr = (p80211_hdr_t *) skb->data;
 295
 296         /* setup some vars for convenience */
 297         fc = le16_to_cpu(w_hdr->a3.fc);
 298         if ((WLAN_GET_FC_TODS(fc) == 0) && (WLAN_GET_FC_FROMDS(fc) == 0)) {
 299                 memcpy(daddr, w_hdr->a3.a1, WLAN_ETHADDR_LEN);
 300                 memcpy(saddr, w_hdr->a3.a2, WLAN_ETHADDR_LEN);
 301         } else if ((WLAN_GET_FC_TODS(fc) == 0) && (WLAN_GET_FC_FROMDS(fc) == 1)) {
 302                 memcpy(daddr, w_hdr->a3.a1, WLAN_ETHADDR_LEN);
 303                 memcpy(saddr, w_hdr->a3.a3, WLAN_ETHADDR_LEN);
 304         } else if ((WLAN_GET_FC_TODS(fc) == 1) && (WLAN_GET_FC_FROMDS(fc) == 0)) {
 305                 memcpy(daddr, w_hdr->a3.a3, WLAN_ETHADDR_LEN);
 306                 memcpy(saddr, w_hdr->a3.a2, WLAN_ETHADDR_LEN);
 307         } else {
 308                 payload_offset = WLAN_HDR_A4_LEN;
 309                 if (payload_length < WLAN_HDR_A4_LEN - WLAN_HDR_A3_LEN) {
 310                         printk(KERN_ERR "A4 frame too short!\n");
 311                         return 1;
 312                 }
 313                 payload_length -= (WLAN_HDR_A4_LEN - WLAN_HDR_A3_LEN);
 314                 memcpy(daddr, w_hdr->a4.a3, WLAN_ETHADDR_LEN);
 315                 memcpy(saddr, w_hdr->a4.a4, WLAN_ETHADDR_LEN);
 316         }
 317
 318         /* perform de-wep if necessary.. */
 319         if ((wlandev->hostwep & HOSTWEP_PRIVACYINVOKED) && WLAN_GET_FC_ISWEP(fc)
 320             && (wlandev->hostwep & HOSTWEP_DECRYPT)) {
 321                 if (payload_length <= 8) {
 322                         printk(KERN_ERR "WEP frame too short (%u).\n",
 323                                skb->len);
 324                         return 1;
 325                 }
 326                 if ((foo = wep_decrypt(wlandev, skb->data + payload_offset + 4,
 327                                        payload_length - 8, -1,
 328                                        skb->data + payload_offset,
 329                                        skb->data + payload_offset +
 330                                        payload_length - 4))) {
 331                         /* de-wep failed, drop skb. */
 332                         pr_debug("Host de-WEP failed, dropping frame (%d).\n",
 333                                  foo);
 334                         wlandev->rx.decrypt_err++;
 335                         return 2;
 336                 }
 337
 338                 /* subtract the IV+ICV length off the payload */
 339                 payload_length -= 8;
 340                 /* chop off the IV */
 341                 skb_pull(skb, 4);
 342                 /* chop off the ICV. */
 343                 skb_trim(skb, skb->len - 4);
 344
 345                 wlandev->rx.decrypt++;
 346         }
 347
 348         e_hdr = (wlan_ethhdr_t *) (skb->data + payload_offset);
 349
 350         e_llc = (wlan_llc_t *) (skb->data + payload_offset);
 351         e_snap =
 352             (wlan_snap_t *) (skb->data + payload_offset + sizeof(wlan_llc_t));
 353
 354         /* Test for the various encodings */
 355         if ((payload_length >= sizeof(wlan_ethhdr_t)) &&
 356             (e_llc->dsap != 0xaa || e_llc->ssap != 0xaa) &&
 357             ((memcmp(daddr, e_hdr->daddr, WLAN_ETHADDR_LEN) == 0) ||
 358              (memcmp(saddr, e_hdr->saddr, WLAN_ETHADDR_LEN) == 0))) {
 359                 pr_debug("802.3 ENCAP len: %d\n", payload_length);
 360                 /* 802.3 Encapsulated */
 361                 /* Test for an overlength frame */
 362                 if (payload_length > (netdev->mtu + WLAN_ETHHDR_LEN)) {
 363                         /* A bogus length ethfrm has been encap'd. */
 364                         /* Is someone trying an oflow attack? */
 365                         printk(KERN_ERR "ENCAP frame too large (%d > %d)\n",
 366                                payload_length, netdev->mtu + WLAN_ETHHDR_LEN);
 367                         return 1;
 368                 }
 369
 370                 /* Chop off the 802.11 header.  it's already sane. */
 371                 skb_pull(skb, payload_offset);
 372                 /* chop off the 802.11 CRC */
 373                 skb_trim(skb, skb->len - WLAN_CRC_LEN);
 374
 375         } else if ((payload_length >= sizeof(wlan_llc_t) + sizeof(wlan_snap_t))
 376                    && (e_llc->dsap == 0xaa) && (e_llc->ssap == 0xaa)
 377                    && (e_llc->ctl == 0x03)
 378                    &&
 379                    (((memcmp(e_snap->oui, oui_rfc1042, WLAN_IEEE_OUI_LEN) == 0)
 380                      && (ethconv == WLAN_ETHCONV_8021h)
 381                      && (p80211_stt_findproto(le16_to_cpu(e_snap->type))))
 382                     || (memcmp(e_snap->oui, oui_rfc1042, WLAN_IEEE_OUI_LEN) !=
 383                         0))) {
 384                 pr_debug("SNAP+RFC1042 len: %d\n", payload_length);
 385                 /* it's a SNAP + RFC1042 frame && protocol is in STT */
 386                 /* build 802.3 + RFC1042 */
 387
 388                 /* Test for an overlength frame */
 389                 if (payload_length > netdev->mtu) {
 390                         /* A bogus length ethfrm has been sent. */
 391                         /* Is someone trying an oflow attack? */
 392                         printk(KERN_ERR "SNAP frame too large (%d > %d)\n",
 393                                payload_length, netdev->mtu);
 394                         return 1;
 395                 }
 396
 397                 /* chop 802.11 header from skb. */
 398                 skb_pull(skb, payload_offset);
 399
 400                 /* create 802.3 header at beginning of skb. */
 401                 e_hdr = (wlan_ethhdr_t *) skb_push(skb, WLAN_ETHHDR_LEN);
 402                 memcpy(e_hdr->daddr, daddr, WLAN_ETHADDR_LEN);
 403                 memcpy(e_hdr->saddr, saddr, WLAN_ETHADDR_LEN);
 404                 e_hdr->type = htons(payload_length);
 405
 406                 /* chop off the 802.11 CRC */
 407                 skb_trim(skb, skb->len - WLAN_CRC_LEN);
 408
 409         } else if ((payload_length >= sizeof(wlan_llc_t) + sizeof(wlan_snap_t))
 410                    && (e_llc->dsap == 0xaa) && (e_llc->ssap == 0xaa)
 411                    && (e_llc->ctl == 0x03)) {
 412                 pr_debug("802.1h/RFC1042 len: %d\n", payload_length);
 413                 /* it's an 802.1h frame || (an RFC1042 && protocol is not in STT) */
 414                 /* build a DIXII + RFC894 */
 415
 416                 /* Test for an overlength frame */
 417                 if ((payload_length - sizeof(wlan_llc_t) - sizeof(wlan_snap_t))
 418                     > netdev->mtu) {
 419                         /* A bogus length ethfrm has been sent. */
 420                         /* Is someone trying an oflow attack? */
 421                         printk(KERN_ERR "DIXII frame too large (%ld > %d)\n",
 422                                (long int)(payload_length - sizeof(wlan_llc_t) -
 423                                           sizeof(wlan_snap_t)), netdev->mtu);
 424                         return 1;
 425                 }
 426
 427                 /* chop 802.11 header from skb. */
 428                 skb_pull(skb, payload_offset);
 429
 430                 /* chop llc header from skb. */
 431                 skb_pull(skb, sizeof(wlan_llc_t));
 432
 433                 /* chop snap header from skb. */
 434                 skb_pull(skb, sizeof(wlan_snap_t));
 435
 436                 /* create 802.3 header at beginning of skb. */
 437                 e_hdr = (wlan_ethhdr_t *) skb_push(skb, WLAN_ETHHDR_LEN);
 438                 e_hdr->type = e_snap->type;
 439                 memcpy(e_hdr->daddr, daddr, WLAN_ETHADDR_LEN);
 440                 memcpy(e_hdr->saddr, saddr, WLAN_ETHADDR_LEN);
 441
 442                 /* chop off the 802.11 CRC */
 443                 skb_trim(skb, skb->len - WLAN_CRC_LEN);
 444         } else {
 445                 pr_debug("NON-ENCAP len: %d\n", payload_length);
 446                 /* any NON-ENCAP */
 447                 /* it's a generic 80211+LLC or IPX 'Raw 802.3' */
 448                 /*  build an 802.3 frame */
 449                 /* allocate space and setup hostbuf */
 450
 451                 /* Test for an overlength frame */
 452                 if (payload_length > netdev->mtu) {
 453                         /* A bogus length ethfrm has been sent. */
 454                         /* Is someone trying an oflow attack? */
 455                         printk(KERN_ERR "OTHER frame too large (%d > %d)\n",
 456                                payload_length, netdev->mtu);
 457                         return 1;
 458                 }
 459
 460                 /* Chop off the 802.11 header. */
 461                 skb_pull(skb, payload_offset);
 462
 463                 /* create 802.3 header at beginning of skb. */
 464                 e_hdr = (wlan_ethhdr_t *) skb_push(skb, WLAN_ETHHDR_LEN);
 465                 memcpy(e_hdr->daddr, daddr, WLAN_ETHADDR_LEN);
 466                 memcpy(e_hdr->saddr, saddr, WLAN_ETHADDR_LEN);
 467                 e_hdr->type = htons(payload_length);
 468
 469                 /* chop off the 802.11 CRC */
 470                 skb_trim(skb, skb->len - WLAN_CRC_LEN);
 471
 472         }
 473
 474         /*
 475          * Note that eth_type_trans() expects an skb w/ skb->data pointing
 476          * at the MAC header, it then sets the following skb members:
 477          * skb->mac_header,
 478          * skb->data, and
 479          * skb->pkt_type.
 480          * It then _returns_ the value that _we're_ supposed to stuff in
 481          * skb->protocol.  This is nuts.
 482          */
 483         skb->protocol = eth_type_trans(skb, netdev);
 484
 485         /* jkriegl: process signal and noise as set in hfa384x_int_rx() */
 486         /* jkriegl: only process signal/noise if requested by iwspy */
 487         if (wlandev->spy_number)
 488                 orinoco_spy_gather(wlandev, eth_hdr(skb)->h_source,
 489                                    P80211SKB_RXMETA(skb));
 490
 491         /* Free the metadata */
 492         p80211skb_rxmeta_detach(skb);
 493
 494         return 0;
 495 }
 496
 497 /*----------------------------------------------------------------
 498 * p80211_stt_findproto
 499 *
 500 * Searches the 802.1h Selective Translation Table for a given
 501 * protocol.
 502 *
 503 * Arguments:
 504 *       proto   protocl number (in host order) to search for.
 505 *
 506 * Returns:
 507 *       1 - if the table is empty or a match is found.
 508 *       0 - if the table is non-empty and a match is not found.
 509 *
 510 * Call context:
 511 *       May be called in interrupt or non-interrupt context
 512 ----------------------------------------------------------------*/
 513 int p80211_stt_findproto(u16 proto)
 514 {
 515         /* Always return found for now.  This is the behavior used by the */
 516         /*  Zoom Win95 driver when 802.1h mode is selected */
 517         /* TODO: If necessary, add an actual search we'll probably
 518            need this to match the CMAC's way of doing things.
 519            Need to do some testing to confirm.
 520          */
 521
 522         if (proto == 0x80f3)    /* APPLETALK */
 523                 return 1;
 524
 525         return 0;
 526 }
 527
 528 /*----------------------------------------------------------------
 529 * p80211skb_rxmeta_detach
 530 *
 531 * Disconnects the frmmeta and rxmeta from an skb.
 532 *
 533 * Arguments:
 534 *       wlandev         The wlandev this skb belongs to.
 535 *       skb             The skb we're attaching to.
 536 *
 537 * Returns:
 538 *       0 on success, non-zero otherwise
 539 *
 540 * Call context:
 541 *       May be called in interrupt or non-interrupt context
 542 ----------------------------------------------------------------*/
 543 void p80211skb_rxmeta_detach(struct sk_buff *skb)
 544 {
 545         p80211_rxmeta_t *rxmeta;
 546         p80211_frmmeta_t *frmmeta;
 547
 548         /* Sanity checks */
 549         if (skb == NULL) {      /* bad skb */
 550                 pr_debug("Called w/ null skb.\n");
 551                 goto exit;
 552         }
 553         frmmeta = P80211SKB_FRMMETA(skb);
 554         if (frmmeta == NULL) {  /* no magic */
 555                 pr_debug("Called w/ bad frmmeta magic.\n");
 556                 goto exit;
 557         }
 558         rxmeta = frmmeta->rx;
 559         if (rxmeta == NULL) {   /* bad meta ptr */
 560                 pr_debug("Called w/ bad rxmeta ptr.\n");
 561                 goto exit;
 562         }
 563
 564         /* Free rxmeta */
 565         kfree(rxmeta);
 566
 567         /* Clear skb->cb */
 568         memset(skb->cb, 0, sizeof(skb->cb));
 569 exit:
 570         return;
 571 }
 572
 573 /*----------------------------------------------------------------
 574 * p80211skb_rxmeta_attach
 575 *
 576 * Allocates a p80211rxmeta structure, initializes it, and attaches
 577 * it to an skb.
 578 *
 579 * Arguments:
 580 *       wlandev         The wlandev this skb belongs to.
 581 *       skb             The skb we're attaching to.
 582 *
 583 * Returns:
 584 *       0 on success, non-zero otherwise
 585 *
 586 * Call context:
 587 *       May be called in interrupt or non-interrupt context
 588 ----------------------------------------------------------------*/
 589 int p80211skb_rxmeta_attach(struct wlandevice *wlandev, struct sk_buff *skb)
 590 {
 591         int result = 0;
 592         p80211_rxmeta_t *rxmeta;
 593         p80211_frmmeta_t *frmmeta;
 594
 595         /* If these already have metadata, we error out! */
 596         if (P80211SKB_RXMETA(skb) != NULL) {
 597                 printk(KERN_ERR "%s: RXmeta already attached!\n",
 598                        wlandev->name);
 599                 result = 0;
 600                 goto exit;
 601         }
 602
 603         /* Allocate the rxmeta */
 604         rxmeta = kmalloc(sizeof(p80211_rxmeta_t), GFP_ATOMIC);
 605
 606         if (rxmeta == NULL) {
 607                 printk(KERN_ERR "%s: Failed to allocate rxmeta.\n",
 608                        wlandev->name);
 609                 result = 1;
 610                 goto exit;
 611         }
 612
 613         /* Initialize the rxmeta */
 614         memset(rxmeta, 0, sizeof(p80211_rxmeta_t));
 615         rxmeta->wlandev = wlandev;
 616         rxmeta->hosttime = jiffies;
 617
 618         /* Overlay a frmmeta_t onto skb->cb */
 619         memset(skb->cb, 0, sizeof(p80211_frmmeta_t));
 620         frmmeta = (p80211_frmmeta_t *) (skb->cb);
 621         frmmeta->magic = P80211_FRMMETA_MAGIC;
 622         frmmeta->rx = rxmeta;
 623 exit:
 624         return result;
 625 }
 626
 627 /*----------------------------------------------------------------
 628 * p80211skb_free
 629 *
 630 * Frees an entire p80211skb by checking and freeing the meta struct
 631 * and then freeing the skb.
 632 *
 633 * Arguments:
 634 *       wlandev         The wlandev this skb belongs to.
 635 *       skb             The skb we're attaching to.
 636 *
 637 * Returns:
 638 *       0 on success, non-zero otherwise
 639 *
 640 * Call context:
 641 *       May be called in interrupt or non-interrupt context
 642 ----------------------------------------------------------------*/
 643 void p80211skb_free(struct wlandevice *wlandev, struct sk_buff *skb)
 644 {
 645         p80211_frmmeta_t *meta;
 646
 647         meta = P80211SKB_FRMMETA(skb);
 648         if (meta && meta->rx)
 649                 p80211skb_rxmeta_detach(skb);
 650         else
 651                 printk(KERN_ERR "Freeing an skb (%p) w/ no frmmeta.\n", skb);
 652         dev_kfree_skb(skb);
 653         return;
 654 }