xref: /linux/net/tls/tls_device.c (revision 791d3ef2e11100449837dc0b6fe884e60ca3a484)
1 /* Copyright (c) 2018, Mellanox Technologies All rights reserved.
2  *
3  * This software is available to you under a choice of one of two
4  * licenses.  You may choose to be licensed under the terms of the GNU
5  * General Public License (GPL) Version 2, available from the file
6  * COPYING in the main directory of this source tree, or the
7  * OpenIB.org BSD license below:
8  *
9  *     Redistribution and use in source and binary forms, with or
10  *     without modification, are permitted provided that the following
11  *     conditions are met:
12  *
13  *      - Redistributions of source code must retain the above
14  *        copyright notice, this list of conditions and the following
15  *        disclaimer.
16  *
17  *      - Redistributions in binary form must reproduce the above
18  *        copyright notice, this list of conditions and the following
19  *        disclaimer in the documentation and/or other materials
20  *        provided with the distribution.
21  *
22  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
23  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
24  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
25  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
26  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
27  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
28  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
29  * SOFTWARE.
30  */
31 
32 #include <crypto/aead.h>
33 #include <linux/highmem.h>
34 #include <linux/module.h>
35 #include <linux/netdevice.h>
36 #include <net/dst.h>
37 #include <net/inet_connection_sock.h>
38 #include <net/tcp.h>
39 #include <net/tls.h>
40 
41 /* device_offload_lock is used to synchronize tls_dev_add
42  * against NETDEV_DOWN notifications.
43  */
44 static DECLARE_RWSEM(device_offload_lock);
45 
46 static void tls_device_gc_task(struct work_struct *work);
47 
48 static DECLARE_WORK(tls_device_gc_work, tls_device_gc_task);
49 static LIST_HEAD(tls_device_gc_list);
50 static LIST_HEAD(tls_device_list);
51 static DEFINE_SPINLOCK(tls_device_lock);
52 
53 static void tls_device_free_ctx(struct tls_context *ctx)
54 {
55 	struct tls_offload_context *offload_ctx = tls_offload_ctx(ctx);
56 
57 	kfree(offload_ctx);
58 	kfree(ctx);
59 }
60 
61 static void tls_device_gc_task(struct work_struct *work)
62 {
63 	struct tls_context *ctx, *tmp;
64 	unsigned long flags;
65 	LIST_HEAD(gc_list);
66 
67 	spin_lock_irqsave(&tls_device_lock, flags);
68 	list_splice_init(&tls_device_gc_list, &gc_list);
69 	spin_unlock_irqrestore(&tls_device_lock, flags);
70 
71 	list_for_each_entry_safe(ctx, tmp, &gc_list, list) {
72 		struct net_device *netdev = ctx->netdev;
73 
74 		if (netdev) {
75 			netdev->tlsdev_ops->tls_dev_del(netdev, ctx,
76 							TLS_OFFLOAD_CTX_DIR_TX);
77 			dev_put(netdev);
78 		}
79 
80 		list_del(&ctx->list);
81 		tls_device_free_ctx(ctx);
82 	}
83 }
84 
85 static void tls_device_queue_ctx_destruction(struct tls_context *ctx)
86 {
87 	unsigned long flags;
88 
89 	spin_lock_irqsave(&tls_device_lock, flags);
90 	list_move_tail(&ctx->list, &tls_device_gc_list);
91 
92 	/* schedule_work inside the spinlock
93 	 * to make sure tls_device_down waits for that work.
94 	 */
95 	schedule_work(&tls_device_gc_work);
96 
97 	spin_unlock_irqrestore(&tls_device_lock, flags);
98 }
99 
100 /* We assume that the socket is already connected */
101 static struct net_device *get_netdev_for_sock(struct sock *sk)
102 {
103 	struct dst_entry *dst = sk_dst_get(sk);
104 	struct net_device *netdev = NULL;
105 
106 	if (likely(dst)) {
107 		netdev = dst->dev;
108 		dev_hold(netdev);
109 	}
110 
111 	dst_release(dst);
112 
113 	return netdev;
114 }
115 
116 static void destroy_record(struct tls_record_info *record)
117 {
118 	int nr_frags = record->num_frags;
119 	skb_frag_t *frag;
120 
121 	while (nr_frags-- > 0) {
122 		frag = &record->frags[nr_frags];
123 		__skb_frag_unref(frag);
124 	}
125 	kfree(record);
126 }
127 
128 static void delete_all_records(struct tls_offload_context *offload_ctx)
129 {
130 	struct tls_record_info *info, *temp;
131 
132 	list_for_each_entry_safe(info, temp, &offload_ctx->records_list, list) {
133 		list_del(&info->list);
134 		destroy_record(info);
135 	}
136 
137 	offload_ctx->retransmit_hint = NULL;
138 }
139 
140 static void tls_icsk_clean_acked(struct sock *sk, u32 acked_seq)
141 {
142 	struct tls_context *tls_ctx = tls_get_ctx(sk);
143 	struct tls_record_info *info, *temp;
144 	struct tls_offload_context *ctx;
145 	u64 deleted_records = 0;
146 	unsigned long flags;
147 
148 	if (!tls_ctx)
149 		return;
150 
151 	ctx = tls_offload_ctx(tls_ctx);
152 
153 	spin_lock_irqsave(&ctx->lock, flags);
154 	info = ctx->retransmit_hint;
155 	if (info && !before(acked_seq, info->end_seq)) {
156 		ctx->retransmit_hint = NULL;
157 		list_del(&info->list);
158 		destroy_record(info);
159 		deleted_records++;
160 	}
161 
162 	list_for_each_entry_safe(info, temp, &ctx->records_list, list) {
163 		if (before(acked_seq, info->end_seq))
164 			break;
165 		list_del(&info->list);
166 
167 		destroy_record(info);
168 		deleted_records++;
169 	}
170 
171 	ctx->unacked_record_sn += deleted_records;
172 	spin_unlock_irqrestore(&ctx->lock, flags);
173 }
174 
175 /* At this point, there should be no references on this
176  * socket and no in-flight SKBs associated with this
177  * socket, so it is safe to free all the resources.
178  */
179 void tls_device_sk_destruct(struct sock *sk)
180 {
181 	struct tls_context *tls_ctx = tls_get_ctx(sk);
182 	struct tls_offload_context *ctx = tls_offload_ctx(tls_ctx);
183 
184 	if (ctx->open_record)
185 		destroy_record(ctx->open_record);
186 
187 	delete_all_records(ctx);
188 	crypto_free_aead(ctx->aead_send);
189 	ctx->sk_destruct(sk);
190 	clean_acked_data_disable(inet_csk(sk));
191 
192 	if (refcount_dec_and_test(&tls_ctx->refcount))
193 		tls_device_queue_ctx_destruction(tls_ctx);
194 }
195 EXPORT_SYMBOL(tls_device_sk_destruct);
196 
197 static void tls_append_frag(struct tls_record_info *record,
198 			    struct page_frag *pfrag,
199 			    int size)
200 {
201 	skb_frag_t *frag;
202 
203 	frag = &record->frags[record->num_frags - 1];
204 	if (frag->page.p == pfrag->page &&
205 	    frag->page_offset + frag->size == pfrag->offset) {
206 		frag->size += size;
207 	} else {
208 		++frag;
209 		frag->page.p = pfrag->page;
210 		frag->page_offset = pfrag->offset;
211 		frag->size = size;
212 		++record->num_frags;
213 		get_page(pfrag->page);
214 	}
215 
216 	pfrag->offset += size;
217 	record->len += size;
218 }
219 
220 static int tls_push_record(struct sock *sk,
221 			   struct tls_context *ctx,
222 			   struct tls_offload_context *offload_ctx,
223 			   struct tls_record_info *record,
224 			   struct page_frag *pfrag,
225 			   int flags,
226 			   unsigned char record_type)
227 {
228 	struct tcp_sock *tp = tcp_sk(sk);
229 	struct page_frag dummy_tag_frag;
230 	skb_frag_t *frag;
231 	int i;
232 
233 	/* fill prepend */
234 	frag = &record->frags[0];
235 	tls_fill_prepend(ctx,
236 			 skb_frag_address(frag),
237 			 record->len - ctx->tx.prepend_size,
238 			 record_type);
239 
240 	/* HW doesn't care about the data in the tag, because it fills it. */
241 	dummy_tag_frag.page = skb_frag_page(frag);
242 	dummy_tag_frag.offset = 0;
243 
244 	tls_append_frag(record, &dummy_tag_frag, ctx->tx.tag_size);
245 	record->end_seq = tp->write_seq + record->len;
246 	spin_lock_irq(&offload_ctx->lock);
247 	list_add_tail(&record->list, &offload_ctx->records_list);
248 	spin_unlock_irq(&offload_ctx->lock);
249 	offload_ctx->open_record = NULL;
250 	set_bit(TLS_PENDING_CLOSED_RECORD, &ctx->flags);
251 	tls_advance_record_sn(sk, &ctx->tx);
252 
253 	for (i = 0; i < record->num_frags; i++) {
254 		frag = &record->frags[i];
255 		sg_unmark_end(&offload_ctx->sg_tx_data[i]);
256 		sg_set_page(&offload_ctx->sg_tx_data[i], skb_frag_page(frag),
257 			    frag->size, frag->page_offset);
258 		sk_mem_charge(sk, frag->size);
259 		get_page(skb_frag_page(frag));
260 	}
261 	sg_mark_end(&offload_ctx->sg_tx_data[record->num_frags - 1]);
262 
263 	/* all ready, send */
264 	return tls_push_sg(sk, ctx, offload_ctx->sg_tx_data, 0, flags);
265 }
266 
267 static int tls_create_new_record(struct tls_offload_context *offload_ctx,
268 				 struct page_frag *pfrag,
269 				 size_t prepend_size)
270 {
271 	struct tls_record_info *record;
272 	skb_frag_t *frag;
273 
274 	record = kmalloc(sizeof(*record), GFP_KERNEL);
275 	if (!record)
276 		return -ENOMEM;
277 
278 	frag = &record->frags[0];
279 	__skb_frag_set_page(frag, pfrag->page);
280 	frag->page_offset = pfrag->offset;
281 	skb_frag_size_set(frag, prepend_size);
282 
283 	get_page(pfrag->page);
284 	pfrag->offset += prepend_size;
285 
286 	record->num_frags = 1;
287 	record->len = prepend_size;
288 	offload_ctx->open_record = record;
289 	return 0;
290 }
291 
292 static int tls_do_allocation(struct sock *sk,
293 			     struct tls_offload_context *offload_ctx,
294 			     struct page_frag *pfrag,
295 			     size_t prepend_size)
296 {
297 	int ret;
298 
299 	if (!offload_ctx->open_record) {
300 		if (unlikely(!skb_page_frag_refill(prepend_size, pfrag,
301 						   sk->sk_allocation))) {
302 			sk->sk_prot->enter_memory_pressure(sk);
303 			sk_stream_moderate_sndbuf(sk);
304 			return -ENOMEM;
305 		}
306 
307 		ret = tls_create_new_record(offload_ctx, pfrag, prepend_size);
308 		if (ret)
309 			return ret;
310 
311 		if (pfrag->size > pfrag->offset)
312 			return 0;
313 	}
314 
315 	if (!sk_page_frag_refill(sk, pfrag))
316 		return -ENOMEM;
317 
318 	return 0;
319 }
320 
321 static int tls_push_data(struct sock *sk,
322 			 struct iov_iter *msg_iter,
323 			 size_t size, int flags,
324 			 unsigned char record_type)
325 {
326 	struct tls_context *tls_ctx = tls_get_ctx(sk);
327 	struct tls_offload_context *ctx = tls_offload_ctx(tls_ctx);
328 	int tls_push_record_flags = flags | MSG_SENDPAGE_NOTLAST;
329 	int more = flags & (MSG_SENDPAGE_NOTLAST | MSG_MORE);
330 	struct tls_record_info *record = ctx->open_record;
331 	struct page_frag *pfrag;
332 	size_t orig_size = size;
333 	u32 max_open_record_len;
334 	int copy, rc = 0;
335 	bool done = false;
336 	long timeo;
337 
338 	if (flags &
339 	    ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_SENDPAGE_NOTLAST))
340 		return -ENOTSUPP;
341 
342 	if (sk->sk_err)
343 		return -sk->sk_err;
344 
345 	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
346 	rc = tls_complete_pending_work(sk, tls_ctx, flags, &timeo);
347 	if (rc < 0)
348 		return rc;
349 
350 	pfrag = sk_page_frag(sk);
351 
352 	/* TLS_HEADER_SIZE is not counted as part of the TLS record, and
353 	 * we need to leave room for an authentication tag.
354 	 */
355 	max_open_record_len = TLS_MAX_PAYLOAD_SIZE +
356 			      tls_ctx->tx.prepend_size;
357 	do {
358 		rc = tls_do_allocation(sk, ctx, pfrag,
359 				       tls_ctx->tx.prepend_size);
360 		if (rc) {
361 			rc = sk_stream_wait_memory(sk, &timeo);
362 			if (!rc)
363 				continue;
364 
365 			record = ctx->open_record;
366 			if (!record)
367 				break;
368 handle_error:
369 			if (record_type != TLS_RECORD_TYPE_DATA) {
370 				/* avoid sending partial
371 				 * record with type !=
372 				 * application_data
373 				 */
374 				size = orig_size;
375 				destroy_record(record);
376 				ctx->open_record = NULL;
377 			} else if (record->len > tls_ctx->tx.prepend_size) {
378 				goto last_record;
379 			}
380 
381 			break;
382 		}
383 
384 		record = ctx->open_record;
385 		copy = min_t(size_t, size, (pfrag->size - pfrag->offset));
386 		copy = min_t(size_t, copy, (max_open_record_len - record->len));
387 
388 		if (copy_from_iter_nocache(page_address(pfrag->page) +
389 					       pfrag->offset,
390 					   copy, msg_iter) != copy) {
391 			rc = -EFAULT;
392 			goto handle_error;
393 		}
394 		tls_append_frag(record, pfrag, copy);
395 
396 		size -= copy;
397 		if (!size) {
398 last_record:
399 			tls_push_record_flags = flags;
400 			if (more) {
401 				tls_ctx->pending_open_record_frags =
402 						record->num_frags;
403 				break;
404 			}
405 
406 			done = true;
407 		}
408 
409 		if (done || record->len >= max_open_record_len ||
410 		    (record->num_frags >= MAX_SKB_FRAGS - 1)) {
411 			rc = tls_push_record(sk,
412 					     tls_ctx,
413 					     ctx,
414 					     record,
415 					     pfrag,
416 					     tls_push_record_flags,
417 					     record_type);
418 			if (rc < 0)
419 				break;
420 		}
421 	} while (!done);
422 
423 	if (orig_size - size > 0)
424 		rc = orig_size - size;
425 
426 	return rc;
427 }
428 
429 int tls_device_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
430 {
431 	unsigned char record_type = TLS_RECORD_TYPE_DATA;
432 	int rc;
433 
434 	lock_sock(sk);
435 
436 	if (unlikely(msg->msg_controllen)) {
437 		rc = tls_proccess_cmsg(sk, msg, &record_type);
438 		if (rc)
439 			goto out;
440 	}
441 
442 	rc = tls_push_data(sk, &msg->msg_iter, size,
443 			   msg->msg_flags, record_type);
444 
445 out:
446 	release_sock(sk);
447 	return rc;
448 }
449 
450 int tls_device_sendpage(struct sock *sk, struct page *page,
451 			int offset, size_t size, int flags)
452 {
453 	struct iov_iter	msg_iter;
454 	char *kaddr = kmap(page);
455 	struct kvec iov;
456 	int rc;
457 
458 	if (flags & MSG_SENDPAGE_NOTLAST)
459 		flags |= MSG_MORE;
460 
461 	lock_sock(sk);
462 
463 	if (flags & MSG_OOB) {
464 		rc = -ENOTSUPP;
465 		goto out;
466 	}
467 
468 	iov.iov_base = kaddr + offset;
469 	iov.iov_len = size;
470 	iov_iter_kvec(&msg_iter, WRITE | ITER_KVEC, &iov, 1, size);
471 	rc = tls_push_data(sk, &msg_iter, size,
472 			   flags, TLS_RECORD_TYPE_DATA);
473 	kunmap(page);
474 
475 out:
476 	release_sock(sk);
477 	return rc;
478 }
479 
480 struct tls_record_info *tls_get_record(struct tls_offload_context *context,
481 				       u32 seq, u64 *p_record_sn)
482 {
483 	u64 record_sn = context->hint_record_sn;
484 	struct tls_record_info *info;
485 
486 	info = context->retransmit_hint;
487 	if (!info ||
488 	    before(seq, info->end_seq - info->len)) {
489 		/* if retransmit_hint is irrelevant start
490 		 * from the beggining of the list
491 		 */
492 		info = list_first_entry(&context->records_list,
493 					struct tls_record_info, list);
494 		record_sn = context->unacked_record_sn;
495 	}
496 
497 	list_for_each_entry_from(info, &context->records_list, list) {
498 		if (before(seq, info->end_seq)) {
499 			if (!context->retransmit_hint ||
500 			    after(info->end_seq,
501 				  context->retransmit_hint->end_seq)) {
502 				context->hint_record_sn = record_sn;
503 				context->retransmit_hint = info;
504 			}
505 			*p_record_sn = record_sn;
506 			return info;
507 		}
508 		record_sn++;
509 	}
510 
511 	return NULL;
512 }
513 EXPORT_SYMBOL(tls_get_record);
514 
515 static int tls_device_push_pending_record(struct sock *sk, int flags)
516 {
517 	struct iov_iter	msg_iter;
518 
519 	iov_iter_kvec(&msg_iter, WRITE | ITER_KVEC, NULL, 0, 0);
520 	return tls_push_data(sk, &msg_iter, 0, flags, TLS_RECORD_TYPE_DATA);
521 }
522 
523 int tls_set_device_offload(struct sock *sk, struct tls_context *ctx)
524 {
525 	u16 nonce_size, tag_size, iv_size, rec_seq_size;
526 	struct tls_record_info *start_marker_record;
527 	struct tls_offload_context *offload_ctx;
528 	struct tls_crypto_info *crypto_info;
529 	struct net_device *netdev;
530 	char *iv, *rec_seq;
531 	struct sk_buff *skb;
532 	int rc = -EINVAL;
533 	__be64 rcd_sn;
534 
535 	if (!ctx)
536 		goto out;
537 
538 	if (ctx->priv_ctx_tx) {
539 		rc = -EEXIST;
540 		goto out;
541 	}
542 
543 	start_marker_record = kmalloc(sizeof(*start_marker_record), GFP_KERNEL);
544 	if (!start_marker_record) {
545 		rc = -ENOMEM;
546 		goto out;
547 	}
548 
549 	offload_ctx = kzalloc(TLS_OFFLOAD_CONTEXT_SIZE, GFP_KERNEL);
550 	if (!offload_ctx) {
551 		rc = -ENOMEM;
552 		goto free_marker_record;
553 	}
554 
555 	crypto_info = &ctx->crypto_send;
556 	switch (crypto_info->cipher_type) {
557 	case TLS_CIPHER_AES_GCM_128:
558 		nonce_size = TLS_CIPHER_AES_GCM_128_IV_SIZE;
559 		tag_size = TLS_CIPHER_AES_GCM_128_TAG_SIZE;
560 		iv_size = TLS_CIPHER_AES_GCM_128_IV_SIZE;
561 		iv = ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->iv;
562 		rec_seq_size = TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE;
563 		rec_seq =
564 		 ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->rec_seq;
565 		break;
566 	default:
567 		rc = -EINVAL;
568 		goto free_offload_ctx;
569 	}
570 
571 	ctx->tx.prepend_size = TLS_HEADER_SIZE + nonce_size;
572 	ctx->tx.tag_size = tag_size;
573 	ctx->tx.overhead_size = ctx->tx.prepend_size + ctx->tx.tag_size;
574 	ctx->tx.iv_size = iv_size;
575 	ctx->tx.iv = kmalloc(iv_size + TLS_CIPHER_AES_GCM_128_SALT_SIZE,
576 			     GFP_KERNEL);
577 	if (!ctx->tx.iv) {
578 		rc = -ENOMEM;
579 		goto free_offload_ctx;
580 	}
581 
582 	memcpy(ctx->tx.iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE, iv, iv_size);
583 
584 	ctx->tx.rec_seq_size = rec_seq_size;
585 	ctx->tx.rec_seq = kmalloc(rec_seq_size, GFP_KERNEL);
586 	if (!ctx->tx.rec_seq) {
587 		rc = -ENOMEM;
588 		goto free_iv;
589 	}
590 	memcpy(ctx->tx.rec_seq, rec_seq, rec_seq_size);
591 
592 	rc = tls_sw_fallback_init(sk, offload_ctx, crypto_info);
593 	if (rc)
594 		goto free_rec_seq;
595 
596 	/* start at rec_seq - 1 to account for the start marker record */
597 	memcpy(&rcd_sn, ctx->tx.rec_seq, sizeof(rcd_sn));
598 	offload_ctx->unacked_record_sn = be64_to_cpu(rcd_sn) - 1;
599 
600 	start_marker_record->end_seq = tcp_sk(sk)->write_seq;
601 	start_marker_record->len = 0;
602 	start_marker_record->num_frags = 0;
603 
604 	INIT_LIST_HEAD(&offload_ctx->records_list);
605 	list_add_tail(&start_marker_record->list, &offload_ctx->records_list);
606 	spin_lock_init(&offload_ctx->lock);
607 	sg_init_table(offload_ctx->sg_tx_data,
608 		      ARRAY_SIZE(offload_ctx->sg_tx_data));
609 
610 	clean_acked_data_enable(inet_csk(sk), &tls_icsk_clean_acked);
611 	ctx->push_pending_record = tls_device_push_pending_record;
612 	offload_ctx->sk_destruct = sk->sk_destruct;
613 
614 	/* TLS offload is greatly simplified if we don't send
615 	 * SKBs where only part of the payload needs to be encrypted.
616 	 * So mark the last skb in the write queue as end of record.
617 	 */
618 	skb = tcp_write_queue_tail(sk);
619 	if (skb)
620 		TCP_SKB_CB(skb)->eor = 1;
621 
622 	refcount_set(&ctx->refcount, 1);
623 
624 	/* We support starting offload on multiple sockets
625 	 * concurrently, so we only need a read lock here.
626 	 * This lock must precede get_netdev_for_sock to prevent races between
627 	 * NETDEV_DOWN and setsockopt.
628 	 */
629 	down_read(&device_offload_lock);
630 	netdev = get_netdev_for_sock(sk);
631 	if (!netdev) {
632 		pr_err_ratelimited("%s: netdev not found\n", __func__);
633 		rc = -EINVAL;
634 		goto release_lock;
635 	}
636 
637 	if (!(netdev->features & NETIF_F_HW_TLS_TX)) {
638 		rc = -ENOTSUPP;
639 		goto release_netdev;
640 	}
641 
642 	/* Avoid offloading if the device is down
643 	 * We don't want to offload new flows after
644 	 * the NETDEV_DOWN event
645 	 */
646 	if (!(netdev->flags & IFF_UP)) {
647 		rc = -EINVAL;
648 		goto release_netdev;
649 	}
650 
651 	ctx->priv_ctx_tx = offload_ctx;
652 	rc = netdev->tlsdev_ops->tls_dev_add(netdev, sk, TLS_OFFLOAD_CTX_DIR_TX,
653 					     &ctx->crypto_send,
654 					     tcp_sk(sk)->write_seq);
655 	if (rc)
656 		goto release_netdev;
657 
658 	ctx->netdev = netdev;
659 
660 	spin_lock_irq(&tls_device_lock);
661 	list_add_tail(&ctx->list, &tls_device_list);
662 	spin_unlock_irq(&tls_device_lock);
663 
664 	sk->sk_validate_xmit_skb = tls_validate_xmit_skb;
665 	/* following this assignment tls_is_sk_tx_device_offloaded
666 	 * will return true and the context might be accessed
667 	 * by the netdev's xmit function.
668 	 */
669 	smp_store_release(&sk->sk_destruct,
670 			  &tls_device_sk_destruct);
671 	up_read(&device_offload_lock);
672 	goto out;
673 
674 release_netdev:
675 	dev_put(netdev);
676 release_lock:
677 	up_read(&device_offload_lock);
678 	clean_acked_data_disable(inet_csk(sk));
679 	crypto_free_aead(offload_ctx->aead_send);
680 free_rec_seq:
681 	kfree(ctx->tx.rec_seq);
682 free_iv:
683 	kfree(ctx->tx.iv);
684 free_offload_ctx:
685 	kfree(offload_ctx);
686 	ctx->priv_ctx_tx = NULL;
687 free_marker_record:
688 	kfree(start_marker_record);
689 out:
690 	return rc;
691 }
692 
693 static int tls_device_down(struct net_device *netdev)
694 {
695 	struct tls_context *ctx, *tmp;
696 	unsigned long flags;
697 	LIST_HEAD(list);
698 
699 	/* Request a write lock to block new offload attempts */
700 	down_write(&device_offload_lock);
701 
702 	spin_lock_irqsave(&tls_device_lock, flags);
703 	list_for_each_entry_safe(ctx, tmp, &tls_device_list, list) {
704 		if (ctx->netdev != netdev ||
705 		    !refcount_inc_not_zero(&ctx->refcount))
706 			continue;
707 
708 		list_move(&ctx->list, &list);
709 	}
710 	spin_unlock_irqrestore(&tls_device_lock, flags);
711 
712 	list_for_each_entry_safe(ctx, tmp, &list, list)	{
713 		netdev->tlsdev_ops->tls_dev_del(netdev, ctx,
714 						TLS_OFFLOAD_CTX_DIR_TX);
715 		ctx->netdev = NULL;
716 		dev_put(netdev);
717 		list_del_init(&ctx->list);
718 
719 		if (refcount_dec_and_test(&ctx->refcount))
720 			tls_device_free_ctx(ctx);
721 	}
722 
723 	up_write(&device_offload_lock);
724 
725 	flush_work(&tls_device_gc_work);
726 
727 	return NOTIFY_DONE;
728 }
729 
730 static int tls_dev_event(struct notifier_block *this, unsigned long event,
731 			 void *ptr)
732 {
733 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
734 
735 	if (!(dev->features & NETIF_F_HW_TLS_TX))
736 		return NOTIFY_DONE;
737 
738 	switch (event) {
739 	case NETDEV_REGISTER:
740 	case NETDEV_FEAT_CHANGE:
741 		if  (dev->tlsdev_ops &&
742 		     dev->tlsdev_ops->tls_dev_add &&
743 		     dev->tlsdev_ops->tls_dev_del)
744 			return NOTIFY_DONE;
745 		else
746 			return NOTIFY_BAD;
747 	case NETDEV_DOWN:
748 		return tls_device_down(dev);
749 	}
750 	return NOTIFY_DONE;
751 }
752 
753 static struct notifier_block tls_dev_notifier = {
754 	.notifier_call	= tls_dev_event,
755 };
756 
757 void __init tls_device_init(void)
758 {
759 	register_netdevice_notifier(&tls_dev_notifier);
760 }
761 
762 void __exit tls_device_cleanup(void)
763 {
764 	unregister_netdevice_notifier(&tls_dev_notifier);
765 	flush_work(&tls_device_gc_work);
766 }
767