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V4L/DVB (4287): Pvrusb2/: possible cleanups
[usb.git] / net / ieee80211 / ieee80211_tx.c
blob6a5de1b84459c147864406522e7c682a03e473ca
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 James P. Ketrenos <ipw2100-admin@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/config.h>
28 #include <linux/errno.h>
29 #include <linux/if_arp.h>
30 #include <linux/in6.h>
31 #include <linux/in.h>
32 #include <linux/ip.h>
33 #include <linux/kernel.h>
34 #include <linux/module.h>
35 #include <linux/netdevice.h>
36 #include <linux/proc_fs.h>
37 #include <linux/skbuff.h>
38 #include <linux/slab.h>
39 #include <linux/tcp.h>
40 #include <linux/types.h>
41 #include <linux/wireless.h>
42 #include <linux/etherdevice.h>
43 #include <asm/uaccess.h>
44
45 #include <net/ieee80211.h>
46
47 /*
48
49 802.11 Data Frame
50
51 ,-------------------------------------------------------------------.
52 Bytes | 2 | 2 | 6 | 6 | 6 | 2 | 0..2312 | 4 |
53 |------|------|---------|---------|---------|------|---------|------|
54 Desc. | ctrl | dura | DA/RA | TA | SA | Sequ | Frame | fcs |
55 | | tion | (BSSID) | | | ence | data | |
56 `--------------------------------------------------| |------'
57 Total: 28 non-data bytes `----.----'
58 |
59 .- 'Frame data' expands, if WEP enabled, to <----------'
60 |
61 V
62 ,-----------------------.
63 Bytes | 4 | 0-2296 | 4 |
64 |-----|-----------|-----|
65 Desc. | IV | Encrypted | ICV |
66 | | Packet | |
67 `-----| |-----'
68 `-----.-----'
69 |
70 .- 'Encrypted Packet' expands to
71 |
72 V
73 ,---------------------------------------------------.
74 Bytes | 1 | 1 | 1 | 3 | 2 | 0-2304 |
75 |------|------|---------|----------|------|---------|
76 Desc. | SNAP | SNAP | Control |Eth Tunnel| Type | IP |
77 | DSAP | SSAP | | | | Packet |
78 | 0xAA | 0xAA |0x03 (UI)|0x00-00-F8| | |
79 `----------------------------------------------------
80 Total: 8 non-data bytes
81
82 802.3 Ethernet Data Frame
83
84 ,-----------------------------------------.
85 Bytes | 6 | 6 | 2 | Variable | 4 |
86 |-------|-------|------|-----------|------|
87 Desc. | Dest. | Source| Type | IP Packet | fcs |
88 | MAC | MAC | | | |
89 `-----------------------------------------'
90 Total: 18 non-data bytes
91
92 In the event that fragmentation is required, the incoming payload is split into
93 N parts of size ieee->fts. The first fragment contains the SNAP header and the
94 remaining packets are just data.
95
96 If encryption is enabled, each fragment payload size is reduced by enough space
97 to add the prefix and postfix (IV and ICV totalling 8 bytes in the case of WEP)
98 So if you have 1500 bytes of payload with ieee->fts set to 500 without
99 encryption it will take 3 frames. With WEP it will take 4 frames as the
100 payload of each frame is reduced to 492 bytes.
101
102 * SKB visualization
103 *
104 * ,- skb->data
105 * |
106 * | ETHERNET HEADER ,-<-- PAYLOAD
107 * | | 14 bytes from skb->data
108 * | 2 bytes for Type --> ,T. | (sizeof ethhdr)
109 * | | | |
110 * |,-Dest.--. ,--Src.---. | | |
111 * | 6 bytes| | 6 bytes | | | |
112 * v | | | | | |
113 * 0 | v 1 | v | v 2
114 * 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
115 * ^ | ^ | ^ |
116 * | | | | | |
117 * | | | | `T' <---- 2 bytes for Type
118 * | | | |
119 * | | '---SNAP--' <-------- 6 bytes for SNAP
120 * | |
121 * `-IV--' <-------------------- 4 bytes for IV (WEP)
122 *
123 * SNAP HEADER
124 *
125 */
126
127 static u8 P802_1H_OUI[P80211_OUI_LEN] = { 0x00, 0x00, 0xf8 };
128 static u8 RFC1042_OUI[P80211_OUI_LEN] = { 0x00, 0x00, 0x00 };
129
130 static int ieee80211_copy_snap(u8 * data, u16 h_proto)
131 {
132 struct ieee80211_snap_hdr *snap;
133 u8 *oui;
134
135 snap = (struct ieee80211_snap_hdr *)data;
136 snap->dsap = 0xaa;
137 snap->ssap = 0xaa;
138 snap->ctrl = 0x03;
139
140 if (h_proto == 0x8137 || h_proto == 0x80f3)
141 oui = P802_1H_OUI;
142 else
143 oui = RFC1042_OUI;
144 snap->oui[0] = oui[0];
145 snap->oui[1] = oui[1];
146 snap->oui[2] = oui[2];
147
148 *(u16 *) (data + SNAP_SIZE) = htons(h_proto);
149
150 return SNAP_SIZE + sizeof(u16);
151 }
152
153 static int ieee80211_encrypt_fragment(struct ieee80211_device *ieee,
154 struct sk_buff *frag, int hdr_len)
155 {
156 struct ieee80211_crypt_data *crypt = ieee->crypt[ieee->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 ieee80211_txb_free(struct ieee80211_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 ieee80211_txb *ieee80211_alloc_txb(int nr_frags, int txb_size,
192 int headroom, gfp_t gfp_mask)
193 {
194 struct ieee80211_txb *txb;
195 int i;
196 txb = kmalloc(sizeof(struct ieee80211_txb) + (sizeof(u8 *) * nr_frags),
197 gfp_mask);
198 if (!txb)
199 return NULL;
200
201 memset(txb, 0, sizeof(struct ieee80211_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 ieee80211_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 != __constant_htons(ETH_P_IP))
230 return 0;
231
232 ip = skb->nh.iph;
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 int ieee80211_xmit(struct sk_buff *skb, struct net_device *dev)
256 {
257 struct ieee80211_device *ieee = netdev_priv(dev);
258 struct ieee80211_txb *txb = NULL;
259 struct ieee80211_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 struct net_device_stats *stats = &ieee->stats;
264 int ether_type, encrypt, host_encrypt, host_encrypt_msdu, host_build_iv;
265 int bytes, fc, hdr_len;
266 struct sk_buff *skb_frag;
267 struct ieee80211_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 ieee80211_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 = ntohs(((struct ethhdr *)skb->data)->h_proto);
296
297 crypt = ieee->crypt[ieee->tx_keyidx];
298
299 encrypt = !(ether_type == ETH_P_PAE && ieee->ieee802_1x) &&
300 ieee->sec.encrypt;
301
302 host_encrypt = ieee->host_encrypt && encrypt && crypt;
303 host_encrypt_msdu = ieee->host_encrypt_msdu && encrypt && crypt;
304 host_build_iv = ieee->host_build_iv && encrypt && crypt;
305
306 if (!encrypt && ieee->ieee802_1x &&
307 ieee->drop_unencrypted && ether_type != ETH_P_PAE) {
308 stats->tx_dropped++;
309 goto success;
310 }
311
312 /* Save source and destination addresses */
313 memcpy(dest, skb->data, ETH_ALEN);
314 memcpy(src, skb->data + ETH_ALEN, ETH_ALEN);
315
316 if (host_encrypt || host_build_iv)
317 fc = IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA |
318 IEEE80211_FCTL_PROTECTED;
319 else
320 fc = IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA;
321
322 if (ieee->iw_mode == IW_MODE_INFRA) {
323 fc |= IEEE80211_FCTL_TODS;
324 /* To DS: Addr1 = BSSID, Addr2 = SA, Addr3 = DA */
325 memcpy(header.addr1, ieee->bssid, ETH_ALEN);
326 memcpy(header.addr2, src, ETH_ALEN);
327 memcpy(header.addr3, dest, ETH_ALEN);
328 } else if (ieee->iw_mode == IW_MODE_ADHOC) {
329 /* not From/To DS: Addr1 = DA, Addr2 = SA, Addr3 = BSSID */
330 memcpy(header.addr1, dest, ETH_ALEN);
331 memcpy(header.addr2, src, ETH_ALEN);
332 memcpy(header.addr3, ieee->bssid, ETH_ALEN);
333 }
334 hdr_len = IEEE80211_3ADDR_LEN;
335
336 if (ieee->is_qos_active && ieee->is_qos_active(dev, skb)) {
337 fc |= IEEE80211_STYPE_QOS_DATA;
338 hdr_len += 2;
339
340 skb->priority = ieee80211_classify(skb);
341 header.qos_ctl |= skb->priority & IEEE80211_QCTL_TID;
342 }
343 header.frame_ctl = cpu_to_le16(fc);
344
345 /* Advance the SKB to the start of the payload */
346 skb_pull(skb, sizeof(struct ethhdr));
347
348 /* Determine total amount of storage required for TXB packets */
349 bytes = skb->len + SNAP_SIZE + sizeof(u16);
350
351 /* Encrypt msdu first on the whole data packet. */
352 if ((host_encrypt || host_encrypt_msdu) &&
353 crypt && crypt->ops && crypt->ops->encrypt_msdu) {
354 int res = 0;
355 int len = bytes + hdr_len + crypt->ops->extra_msdu_prefix_len +
356 crypt->ops->extra_msdu_postfix_len;
357 struct sk_buff *skb_new = dev_alloc_skb(len);
358
359 if (unlikely(!skb_new))
360 goto failed;
361
362 skb_reserve(skb_new, crypt->ops->extra_msdu_prefix_len);
363 memcpy(skb_put(skb_new, hdr_len), &header, hdr_len);
364 snapped = 1;
365 ieee80211_copy_snap(skb_put(skb_new, SNAP_SIZE + sizeof(u16)),
366 ether_type);
367 memcpy(skb_put(skb_new, skb->len), skb->data, skb->len);
368 res = crypt->ops->encrypt_msdu(skb_new, hdr_len, crypt->priv);
369 if (res < 0) {
370 IEEE80211_ERROR("msdu encryption failed\n");
371 dev_kfree_skb_any(skb_new);
372 goto failed;
373 }
374 dev_kfree_skb_any(skb);
375 skb = skb_new;
376 bytes += crypt->ops->extra_msdu_prefix_len +
377 crypt->ops->extra_msdu_postfix_len;
378 skb_pull(skb, hdr_len);
379 }
380
381 if (host_encrypt || ieee->host_open_frag) {
382 /* Determine fragmentation size based on destination (multicast
383 * and broadcast are not fragmented) */
384 if (is_multicast_ether_addr(dest) ||
385 is_broadcast_ether_addr(dest))
386 frag_size = MAX_FRAG_THRESHOLD;
387 else
388 frag_size = ieee->fts;
389
390 /* Determine amount of payload per fragment. Regardless of if
391 * this stack is providing the full 802.11 header, one will
392 * eventually be affixed to this fragment -- so we must account
393 * for it when determining the amount of payload space. */
394 bytes_per_frag = frag_size - IEEE80211_3ADDR_LEN;
395 if (ieee->config &
396 (CFG_IEEE80211_COMPUTE_FCS | CFG_IEEE80211_RESERVE_FCS))
397 bytes_per_frag -= IEEE80211_FCS_LEN;
398
399 /* Each fragment may need to have room for encryptiong
400 * pre/postfix */
401 if (host_encrypt)
402 bytes_per_frag -= crypt->ops->extra_mpdu_prefix_len +
403 crypt->ops->extra_mpdu_postfix_len;
404
405 /* Number of fragments is the total
406 * bytes_per_frag / payload_per_fragment */
407 nr_frags = bytes / bytes_per_frag;
408 bytes_last_frag = bytes % bytes_per_frag;
409 if (bytes_last_frag)
410 nr_frags++;
411 else
412 bytes_last_frag = bytes_per_frag;
413 } else {
414 nr_frags = 1;
415 bytes_per_frag = bytes_last_frag = bytes;
416 frag_size = bytes + IEEE80211_3ADDR_LEN;
417 }
418
419 rts_required = (frag_size > ieee->rts
420 && ieee->config & CFG_IEEE80211_RTS);
421 if (rts_required)
422 nr_frags++;
423
424 /* When we allocate the TXB we allocate enough space for the reserve
425 * and full fragment bytes (bytes_per_frag doesn't include prefix,
426 * postfix, header, FCS, etc.) */
427 txb = ieee80211_alloc_txb(nr_frags, frag_size,
428 ieee->tx_headroom, GFP_ATOMIC);
429 if (unlikely(!txb)) {
430 printk(KERN_WARNING "%s: Could not allocate TXB\n",
431 ieee->dev->name);
432 goto failed;
433 }
434 txb->encrypted = encrypt;
435 if (host_encrypt)
436 txb->payload_size = frag_size * (nr_frags - 1) +
437 bytes_last_frag;
438 else
439 txb->payload_size = bytes;
440
441 if (rts_required) {
442 skb_frag = txb->fragments[0];
443 frag_hdr =
444 (struct ieee80211_hdr_3addrqos *)skb_put(skb_frag, hdr_len);
445
446 /*
447 * Set header frame_ctl to the RTS.
448 */
449 header.frame_ctl =
450 cpu_to_le16(IEEE80211_FTYPE_CTL | IEEE80211_STYPE_RTS);
451 memcpy(frag_hdr, &header, hdr_len);
452
453 /*
454 * Restore header frame_ctl to the original data setting.
455 */
456 header.frame_ctl = cpu_to_le16(fc);
457
458 if (ieee->config &
459 (CFG_IEEE80211_COMPUTE_FCS | CFG_IEEE80211_RESERVE_FCS))
460 skb_put(skb_frag, 4);
461
462 txb->rts_included = 1;
463 i = 1;
464 } else
465 i = 0;
466
467 for (; i < nr_frags; i++) {
468 skb_frag = txb->fragments[i];
469
470 if (host_encrypt || host_build_iv)
471 skb_reserve(skb_frag,
472 crypt->ops->extra_mpdu_prefix_len);
473
474 frag_hdr =
475 (struct ieee80211_hdr_3addrqos *)skb_put(skb_frag, hdr_len);
476 memcpy(frag_hdr, &header, hdr_len);
477
478 /* If this is not the last fragment, then add the MOREFRAGS
479 * bit to the frame control */
480 if (i != nr_frags - 1) {
481 frag_hdr->frame_ctl =
482 cpu_to_le16(fc | IEEE80211_FCTL_MOREFRAGS);
483 bytes = bytes_per_frag;
484 } else {
485 /* The last fragment takes the remaining length */
486 bytes = bytes_last_frag;
487 }
488
489 if (i == 0 && !snapped) {
490 ieee80211_copy_snap(skb_put
491 (skb_frag, SNAP_SIZE + sizeof(u16)),
492 ether_type);
493 bytes -= SNAP_SIZE + sizeof(u16);
494 }
495
496 memcpy(skb_put(skb_frag, bytes), skb->data, bytes);
497
498 /* Advance the SKB... */
499 skb_pull(skb, bytes);
500
501 /* Encryption routine will move the header forward in order
502 * to insert the IV between the header and the payload */
503 if (host_encrypt)
504 ieee80211_encrypt_fragment(ieee, skb_frag, hdr_len);
505 else if (host_build_iv) {
506 struct ieee80211_crypt_data *crypt;
507
508 crypt = ieee->crypt[ieee->tx_keyidx];
509 atomic_inc(&crypt->refcnt);
510 if (crypt->ops->build_iv)
511 crypt->ops->build_iv(skb_frag, hdr_len,
512 ieee->sec.keys[ieee->sec.active_key],
513 ieee->sec.key_sizes[ieee->sec.active_key],
514 crypt->priv);
515 atomic_dec(&crypt->refcnt);
516 }
517
518 if (ieee->config &
519 (CFG_IEEE80211_COMPUTE_FCS | CFG_IEEE80211_RESERVE_FCS))
520 skb_put(skb_frag, 4);
521 }
522
523 success:
524 spin_unlock_irqrestore(&ieee->lock, flags);
525
526 dev_kfree_skb_any(skb);
527
528 if (txb) {
529 int ret = (*ieee->hard_start_xmit) (txb, dev, priority);
530 if (ret == 0) {
531 stats->tx_packets++;
532 stats->tx_bytes += txb->payload_size;
533 return 0;
534 }
535
536 if (ret == NETDEV_TX_BUSY) {
537 printk(KERN_ERR "%s: NETDEV_TX_BUSY returned; "
538 "driver should report queue full via "
539 "ieee_device->is_queue_full.\n",
540 ieee->dev->name);
541 }
542
543 ieee80211_txb_free(txb);
544 }
545
546 return 0;
547
548 failed:
549 spin_unlock_irqrestore(&ieee->lock, flags);
550 netif_stop_queue(dev);
551 stats->tx_errors++;
552 return 1;
553 }
554
555 /* Incoming 802.11 strucure is converted to a TXB
556 * a block of 802.11 fragment packets (stored as skbs) */
557 int ieee80211_tx_frame(struct ieee80211_device *ieee,
558 struct ieee80211_hdr *frame, int hdr_len, int total_len,
559 int encrypt_mpdu)
560 {
561 struct ieee80211_txb *txb = NULL;
562 unsigned long flags;
563 struct net_device_stats *stats = &ieee->stats;
564 struct sk_buff *skb_frag;
565 int priority = -1;
566
567 spin_lock_irqsave(&ieee->lock, flags);
568
569 if (encrypt_mpdu && !ieee->sec.encrypt)
570 encrypt_mpdu = 0;
571
572 /* If there is no driver handler to take the TXB, dont' bother
573 * creating it... */
574 if (!ieee->hard_start_xmit) {
575 printk(KERN_WARNING "%s: No xmit handler.\n", ieee->dev->name);
576 goto success;
577 }
578
579 if (unlikely(total_len < 24)) {
580 printk(KERN_WARNING "%s: skb too small (%d).\n",
581 ieee->dev->name, total_len);
582 goto success;
583 }
584
585 if (encrypt_mpdu)
586 frame->frame_ctl |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
587
588 /* When we allocate the TXB we allocate enough space for the reserve
589 * and full fragment bytes (bytes_per_frag doesn't include prefix,
590 * postfix, header, FCS, etc.) */
591 txb = ieee80211_alloc_txb(1, total_len, ieee->tx_headroom, GFP_ATOMIC);
592 if (unlikely(!txb)) {
593 printk(KERN_WARNING "%s: Could not allocate TXB\n",
594 ieee->dev->name);
595 goto failed;
596 }
597 txb->encrypted = 0;
598 txb->payload_size = total_len;
599
600 skb_frag = txb->fragments[0];
601
602 memcpy(skb_put(skb_frag, total_len), frame, total_len);
603
604 if (ieee->config &
605 (CFG_IEEE80211_COMPUTE_FCS | CFG_IEEE80211_RESERVE_FCS))
606 skb_put(skb_frag, 4);
607
608 /* To avoid overcomplicating things, we do the corner-case frame
609 * encryption in software. The only real situation where encryption is
610 * needed here is during software-based shared key authentication. */
611 if (encrypt_mpdu)
612 ieee80211_encrypt_fragment(ieee, skb_frag, hdr_len);
613
614 success:
615 spin_unlock_irqrestore(&ieee->lock, flags);
616
617 if (txb) {
618 if ((*ieee->hard_start_xmit) (txb, ieee->dev, priority) == 0) {
619 stats->tx_packets++;
620 stats->tx_bytes += txb->payload_size;
621 return 0;
622 }
623 ieee80211_txb_free(txb);
624 }
625 return 0;
626
627 failed:
628 spin_unlock_irqrestore(&ieee->lock, flags);
629 stats->tx_errors++;
630 return 1;
631 }
632
633 EXPORT_SYMBOL(ieee80211_tx_frame);
634 EXPORT_SYMBOL(ieee80211_txb_free);
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