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 
55 #include <linux/module.h>
56 #include <linux/kernel.h>
57 #include <linux/sched.h>
58 #include <linux/types.h>
59 #include <linux/skbuff.h>
60 #include <linux/slab.h>
61 #include <linux/wireless.h>
62 #include <linux/netdevice.h>
63 #include <linux/etherdevice.h>
64 #include <linux/if_ether.h>
65 #include <linux/byteorder/generic.h>
66 
67 #include <asm/byteorder.h>
68 
69 #include "p80211types.h"
70 #include "p80211hdr.h"
71 #include "p80211conv.h"
72 #include "p80211mgmt.h"
73 #include "p80211msg.h"
74 #include "p80211netdev.h"
75 #include "p80211ioctl.h"
76 #include "p80211req.h"
77 
78 static const u8 oui_rfc1042[] = { 0x00, 0x00, 0x00 };
79 static const u8 oui_8021h[] = { 0x00, 0x00, 0xf8 };
80 
81 /*----------------------------------------------------------------
82 * p80211pb_ether_to_80211
83 *
84 * Uses the contents of the ether frame and the etherconv setting
85 * to build the elements of the 802.11 frame.
86 *
87 * We don't actually set
88 * up the frame header here.  That's the MAC's job.  We're only handling
89 * conversion of DIXII or 802.3+LLC frames to something that works
90 * with 802.11.
91 *
92 * Note -- 802.11 header is NOT part of the skb.  Likewise, the 802.11
93 *         FCS is also not present and will need to be added elsewhere.
94 *
95 * Arguments:
96 *	ethconv		Conversion type to perform
97 *	skb		skbuff containing the ether frame
98 *       p80211_hdr      802.11 header
99 *
100 * Returns:
101 *	0 on success, non-zero otherwise
102 *
103 * Call context:
104 *	May be called in interrupt or non-interrupt context
105 *----------------------------------------------------------------
106 */
107 int skb_ether_to_p80211(wlandevice_t *wlandev, u32 ethconv,
108 			struct sk_buff *skb, union p80211_hdr *p80211_hdr,
109 			struct p80211_metawep *p80211_wep)
110 {
111 	__le16 fc;
112 	u16 proto;
113 	struct wlan_ethhdr e_hdr;
114 	struct wlan_llc *e_llc;
115 	struct wlan_snap *e_snap;
116 	int foo;
117 
118 	memcpy(&e_hdr, skb->data, sizeof(e_hdr));
119 
120 	if (skb->len <= 0) {
121 		pr_debug("zero-length skb!\n");
122 		return 1;
123 	}
124 
125 	if (ethconv == WLAN_ETHCONV_ENCAP) {	/* simplest case */
126 		pr_debug("ENCAP len: %d\n", skb->len);
127 		/* here, we don't care what kind of ether frm. Just stick it */
128 		/*  in the 80211 payload */
129 		/* which is to say, leave the skb alone. */
130 	} else {
131 		/* step 1: classify ether frame, DIX or 802.3? */
132 		proto = ntohs(e_hdr.type);
133 		if (proto <= ETH_DATA_LEN) {
134 			pr_debug("802.3 len: %d\n", skb->len);
135 			/* codes <= 1500 reserved for 802.3 lengths */
136 			/* it's 802.3, pass ether payload unchanged,  */
137 
138 			/* trim off ethernet header */
139 			skb_pull(skb, ETH_HLEN);
140 
141 			/*   leave off any PAD octets.  */
142 			skb_trim(skb, proto);
143 		} else {
144 			pr_debug("DIXII len: %d\n", skb->len);
145 			/* it's DIXII, time for some conversion */
146 
147 			/* trim off ethernet header */
148 			skb_pull(skb, ETH_HLEN);
149 
150 			/* tack on SNAP */
151 			e_snap =
152 			    (struct wlan_snap *)skb_push(skb,
153 				sizeof(struct wlan_snap));
154 			e_snap->type = htons(proto);
155 			if (ethconv == WLAN_ETHCONV_8021h &&
156 			    p80211_stt_findproto(proto)) {
157 				memcpy(e_snap->oui, oui_8021h,
158 				       WLAN_IEEE_OUI_LEN);
159 			} else {
160 				memcpy(e_snap->oui, oui_rfc1042,
161 				       WLAN_IEEE_OUI_LEN);
162 			}
163 
164 			/* tack on llc */
165 			e_llc =
166 			    (struct wlan_llc *)skb_push(skb,
167 				sizeof(struct wlan_llc));
168 			e_llc->dsap = 0xAA;	/* SNAP, see IEEE 802 */
169 			e_llc->ssap = 0xAA;
170 			e_llc->ctl = 0x03;
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 
244 	for (i = 0; i < wlandev->spy_number; i++) {
245 		if (!memcmp(wlandev->spy_address[i], mac, ETH_ALEN)) {
246 			wlandev->spy_stat[i].level = rxmeta->signal;
247 			wlandev->spy_stat[i].noise = rxmeta->noise;
248 			wlandev->spy_stat[i].qual =
249 			    (rxmeta->signal >
250 			     rxmeta->noise) ? (rxmeta->signal -
251 					       rxmeta->noise) : 0;
252 			wlandev->spy_stat[i].updated = 0x7;
253 		}
254 	}
255 }
256 
257 /*----------------------------------------------------------------
258 * p80211pb_80211_to_ether
259 *
260 * Uses the contents of a received 802.11 frame and the etherconv
261 * setting to build an ether frame.
262 *
263 * This function extracts the src and dest address from the 802.11
264 * frame to use in the construction of the eth frame.
265 *
266 * Arguments:
267 *	ethconv		Conversion type to perform
268 *	skb		Packet buffer containing the 802.11 frame
269 *
270 * Returns:
271 *	0 on success, non-zero otherwise
272 *
273 * Call context:
274 *	May be called in interrupt or non-interrupt context
275 *----------------------------------------------------------------
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) &&
324 	    WLAN_GET_FC_ISWEP(fc) &&
325 	    (wlandev->hostwep & HOSTWEP_DECRYPT)) {
326 		if (payload_length <= 8) {
327 			netdev_err(netdev,
328 				   "WEP frame too short (%u).\n", skb->len);
329 			return 1;
330 		}
331 		foo = wep_decrypt(wlandev, skb->data + payload_offset + 4,
332 				  payload_length - 8, -1,
333 				  skb->data + payload_offset,
334 				  skb->data + payload_offset +
335 				  payload_length - 4);
336 		if (foo) {
337 			/* de-wep failed, drop skb. */
338 			pr_debug("Host de-WEP failed, dropping frame (%d).\n",
339 				 foo);
340 			wlandev->rx.decrypt_err++;
341 			return 2;
342 		}
343 
344 		/* subtract the IV+ICV length off the payload */
345 		payload_length -= 8;
346 		/* chop off the IV */
347 		skb_pull(skb, 4);
348 		/* chop off the ICV. */
349 		skb_trim(skb, skb->len - 4);
350 
351 		wlandev->rx.decrypt++;
352 	}
353 
354 	e_hdr = (struct wlan_ethhdr *)(skb->data + payload_offset);
355 
356 	e_llc = (struct wlan_llc *)(skb->data + payload_offset);
357 	e_snap =
358 	    (struct wlan_snap *)(skb->data + payload_offset +
359 		sizeof(struct wlan_llc));
360 
361 	/* Test for the various encodings */
362 	if ((payload_length >= sizeof(struct wlan_ethhdr)) &&
363 	    (e_llc->dsap != 0xaa || e_llc->ssap != 0xaa) &&
364 	    ((!ether_addr_equal_unaligned(daddr, e_hdr->daddr)) ||
365 	     (!ether_addr_equal_unaligned(saddr, e_hdr->saddr)))) {
366 		pr_debug("802.3 ENCAP len: %d\n", payload_length);
367 		/* 802.3 Encapsulated */
368 		/* Test for an overlength frame */
369 		if (payload_length > (netdev->mtu + ETH_HLEN)) {
370 			/* A bogus length ethfrm has been encap'd. */
371 			/* Is someone trying an oflow attack? */
372 			netdev_err(netdev, "ENCAP frame too large (%d > %d)\n",
373 				   payload_length, netdev->mtu + ETH_HLEN);
374 			return 1;
375 		}
376 
377 		/* Chop off the 802.11 header.  it's already sane. */
378 		skb_pull(skb, payload_offset);
379 		/* chop off the 802.11 CRC */
380 		skb_trim(skb, skb->len - WLAN_CRC_LEN);
381 
382 	} else if ((payload_length >= sizeof(struct wlan_llc) +
383 		sizeof(struct wlan_snap)) &&
384 		(e_llc->dsap == 0xaa) &&
385 		(e_llc->ssap == 0xaa) &&
386 		(e_llc->ctl == 0x03) &&
387 		   (((memcmp(e_snap->oui, oui_rfc1042,
388 		   WLAN_IEEE_OUI_LEN) == 0) &&
389 		   (ethconv == WLAN_ETHCONV_8021h) &&
390 		   (p80211_stt_findproto(le16_to_cpu(e_snap->type)))) ||
391 		   (memcmp(e_snap->oui, oui_rfc1042, WLAN_IEEE_OUI_LEN) !=
392 			0))) {
393 		pr_debug("SNAP+RFC1042 len: %d\n", payload_length);
394 		/* it's a SNAP + RFC1042 frame && protocol is in STT */
395 		/* build 802.3 + RFC1042 */
396 
397 		/* Test for an overlength frame */
398 		if (payload_length > netdev->mtu) {
399 			/* A bogus length ethfrm has been sent. */
400 			/* Is someone trying an oflow attack? */
401 			netdev_err(netdev, "SNAP frame too large (%d > %d)\n",
402 				   payload_length, netdev->mtu);
403 			return 1;
404 		}
405 
406 		/* chop 802.11 header from skb. */
407 		skb_pull(skb, payload_offset);
408 
409 		/* create 802.3 header at beginning of skb. */
410 		e_hdr = (struct wlan_ethhdr *)skb_push(skb, ETH_HLEN);
411 		ether_addr_copy(e_hdr->daddr, daddr);
412 		ether_addr_copy(e_hdr->saddr, saddr);
413 		e_hdr->type = htons(payload_length);
414 
415 		/* chop off the 802.11 CRC */
416 		skb_trim(skb, skb->len - WLAN_CRC_LEN);
417 
418 	} else if ((payload_length >= sizeof(struct wlan_llc) +
419 		sizeof(struct wlan_snap)) &&
420 		(e_llc->dsap == 0xaa) &&
421 		(e_llc->ssap == 0xaa) &&
422 		(e_llc->ctl == 0x03)) {
423 		pr_debug("802.1h/RFC1042 len: %d\n", payload_length);
424 		/* it's an 802.1h frame || (an RFC1042 && protocol not in STT)
425 		 * build a DIXII + RFC894
426 		 */
427 
428 		/* Test for an overlength frame */
429 		if ((payload_length - sizeof(struct wlan_llc) -
430 			sizeof(struct wlan_snap))
431 			> netdev->mtu) {
432 			/* A bogus length ethfrm has been sent. */
433 			/* Is someone trying an oflow attack? */
434 			netdev_err(netdev, "DIXII frame too large (%ld > %d)\n",
435 				   (long int)(payload_length -
436 				   sizeof(struct wlan_llc) -
437 				   sizeof(struct wlan_snap)), netdev->mtu);
438 			return 1;
439 		}
440 
441 		/* chop 802.11 header from skb. */
442 		skb_pull(skb, payload_offset);
443 
444 		/* chop llc header from skb. */
445 		skb_pull(skb, sizeof(struct wlan_llc));
446 
447 		/* chop snap header from skb. */
448 		skb_pull(skb, sizeof(struct wlan_snap));
449 
450 		/* create 802.3 header at beginning of skb. */
451 		e_hdr = (struct wlan_ethhdr *)skb_push(skb, ETH_HLEN);
452 		e_hdr->type = e_snap->type;
453 		ether_addr_copy(e_hdr->daddr, daddr);
454 		ether_addr_copy(e_hdr->saddr, saddr);
455 
456 		/* chop off the 802.11 CRC */
457 		skb_trim(skb, skb->len - WLAN_CRC_LEN);
458 	} else {
459 		pr_debug("NON-ENCAP len: %d\n", payload_length);
460 		/* any NON-ENCAP */
461 		/* it's a generic 80211+LLC or IPX 'Raw 802.3' */
462 		/*  build an 802.3 frame */
463 		/* allocate space and setup hostbuf */
464 
465 		/* Test for an overlength frame */
466 		if (payload_length > netdev->mtu) {
467 			/* A bogus length ethfrm has been sent. */
468 			/* Is someone trying an oflow attack? */
469 			netdev_err(netdev, "OTHER frame too large (%d > %d)\n",
470 				   payload_length, netdev->mtu);
471 			return 1;
472 		}
473 
474 		/* Chop off the 802.11 header. */
475 		skb_pull(skb, payload_offset);
476 
477 		/* create 802.3 header at beginning of skb. */
478 		e_hdr = (struct wlan_ethhdr *)skb_push(skb, ETH_HLEN);
479 		ether_addr_copy(e_hdr->daddr, daddr);
480 		ether_addr_copy(e_hdr->saddr, saddr);
481 		e_hdr->type = htons(payload_length);
482 
483 		/* chop off the 802.11 CRC */
484 		skb_trim(skb, skb->len - WLAN_CRC_LEN);
485 	}
486 
487 	/*
488 	 * Note that eth_type_trans() expects an skb w/ skb->data pointing
489 	 * at the MAC header, it then sets the following skb members:
490 	 * skb->mac_header,
491 	 * skb->data, and
492 	 * skb->pkt_type.
493 	 * It then _returns_ the value that _we're_ supposed to stuff in
494 	 * skb->protocol.  This is nuts.
495 	 */
496 	skb->protocol = eth_type_trans(skb, netdev);
497 
498 	/* jkriegl: process signal and noise as set in hfa384x_int_rx() */
499 	/* jkriegl: only process signal/noise if requested by iwspy */
500 	if (wlandev->spy_number)
501 		orinoco_spy_gather(wlandev, eth_hdr(skb)->h_source,
502 				   P80211SKB_RXMETA(skb));
503 
504 	/* Free the metadata */
505 	p80211skb_rxmeta_detach(skb);
506 
507 	return 0;
508 }
509 
510 /*----------------------------------------------------------------
511 * p80211_stt_findproto
512 *
513 * Searches the 802.1h Selective Translation Table for a given
514 * protocol.
515 *
516 * Arguments:
517 *	proto	protocol number (in host order) to search for.
518 *
519 * Returns:
520 *	1 - if the table is empty or a match is found.
521 *	0 - if the table is non-empty and a match is not found.
522 *
523 * Call context:
524 *	May be called in interrupt or non-interrupt context
525 *----------------------------------------------------------------
526 */
527 int p80211_stt_findproto(u16 proto)
528 {
529 	/* Always return found for now.  This is the behavior used by the */
530 	/* Zoom Win95 driver when 802.1h mode is selected */
531 	/* TODO: If necessary, add an actual search we'll probably
532 	 * need this to match the CMAC's way of doing things.
533 	 * Need to do some testing to confirm.
534 	 */
535 
536 	if (proto == ETH_P_AARP)	/* APPLETALK */
537 		return 1;
538 
539 	return 0;
540 }
541 
542 /*----------------------------------------------------------------
543 * p80211skb_rxmeta_detach
544 *
545 * Disconnects the frmmeta and rxmeta from an skb.
546 *
547 * Arguments:
548 *	wlandev		The wlandev this skb belongs to.
549 *	skb		The skb we're attaching to.
550 *
551 * Returns:
552 *	0 on success, non-zero otherwise
553 *
554 * Call context:
555 *	May be called in interrupt or non-interrupt context
556 *----------------------------------------------------------------
557 */
558 void p80211skb_rxmeta_detach(struct sk_buff *skb)
559 {
560 	struct p80211_rxmeta *rxmeta;
561 	struct p80211_frmmeta *frmmeta;
562 
563 	/* Sanity checks */
564 	if (!skb) {	/* bad skb */
565 		pr_debug("Called w/ null skb.\n");
566 		return;
567 	}
568 	frmmeta = P80211SKB_FRMMETA(skb);
569 	if (!frmmeta) {	/* no magic */
570 		pr_debug("Called w/ bad frmmeta magic.\n");
571 		return;
572 	}
573 	rxmeta = frmmeta->rx;
574 	if (!rxmeta) {	/* bad meta ptr */
575 		pr_debug("Called w/ bad rxmeta ptr.\n");
576 		return;
577 	}
578 
579 	/* Free rxmeta */
580 	kfree(rxmeta);
581 
582 	/* Clear skb->cb */
583 	memset(skb->cb, 0, sizeof(skb->cb));
584 }
585 
586 /*----------------------------------------------------------------
587 * p80211skb_rxmeta_attach
588 *
589 * Allocates a p80211rxmeta structure, initializes it, and attaches
590 * it to an skb.
591 *
592 * Arguments:
593 *	wlandev		The wlandev this skb belongs to.
594 *	skb		The skb we're attaching to.
595 *
596 * Returns:
597 *	0 on success, non-zero otherwise
598 *
599 * Call context:
600 *	May be called in interrupt or non-interrupt context
601 *----------------------------------------------------------------
602 */
603 int p80211skb_rxmeta_attach(struct wlandevice *wlandev, struct sk_buff *skb)
604 {
605 	int result = 0;
606 	struct p80211_rxmeta *rxmeta;
607 	struct p80211_frmmeta *frmmeta;
608 
609 	/* If these already have metadata, we error out! */
610 	if (P80211SKB_RXMETA(skb)) {
611 		netdev_err(wlandev->netdev,
612 			   "%s: RXmeta already attached!\n", wlandev->name);
613 		result = 0;
614 		goto exit;
615 	}
616 
617 	/* Allocate the rxmeta */
618 	rxmeta = kzalloc(sizeof(struct p80211_rxmeta), GFP_ATOMIC);
619 
620 	if (!rxmeta) {
621 		netdev_err(wlandev->netdev,
622 			   "%s: Failed to allocate rxmeta.\n", wlandev->name);
623 		result = 1;
624 		goto exit;
625 	}
626 
627 	/* Initialize the rxmeta */
628 	rxmeta->wlandev = wlandev;
629 	rxmeta->hosttime = jiffies;
630 
631 	/* Overlay a frmmeta_t onto skb->cb */
632 	memset(skb->cb, 0, sizeof(struct p80211_frmmeta));
633 	frmmeta = (struct p80211_frmmeta *)(skb->cb);
634 	frmmeta->magic = P80211_FRMMETA_MAGIC;
635 	frmmeta->rx = rxmeta;
636 exit:
637 	return result;
638 }
639 
640 /*----------------------------------------------------------------
641 * p80211skb_free
642 *
643 * Frees an entire p80211skb by checking and freeing the meta struct
644 * and then freeing the skb.
645 *
646 * Arguments:
647 *	wlandev		The wlandev this skb belongs to.
648 *	skb		The skb we're attaching to.
649 *
650 * Returns:
651 *	0 on success, non-zero otherwise
652 *
653 * Call context:
654 *	May be called in interrupt or non-interrupt context
655 *----------------------------------------------------------------
656 */
657 void p80211skb_free(struct wlandevice *wlandev, struct sk_buff *skb)
658 {
659 	struct p80211_frmmeta *meta;
660 
661 	meta = P80211SKB_FRMMETA(skb);
662 	if (meta && meta->rx)
663 		p80211skb_rxmeta_detach(skb);
664 	else
665 		netdev_err(wlandev->netdev,
666 			   "Freeing an skb (%p) w/ no frmmeta.\n", skb);
667 	dev_kfree_skb(skb);
668 }
669