text: /* Copyright (c) 2018, Mellanox Technologies All rights reserved.
   *
   * This software is available to you under a choice of one of two
   * licenses.  You may choose to be licensed under the terms of the GNU
   * General Public License (GPL) Version 2, available from the file
   * COPYING in the main directory of this source tree, or the
   * OpenIB.org BSD license below:
   *
   *     Redistribution and use in source and binary forms, with or
   *     without modification, are permitted provided that the following
   *     conditions are met:
   *
   *      - Redistributions of source code must retain the above
   *        copyright notice, this list of conditions and the following
   *        disclaimer.
   *
   *      - Redistributions in binary form must reproduce the above
   *        copyright notice, this list of conditions and the following
   *        disclaimer in the documentation and/or other materials
   *        provided with the distribution.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
   * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
   * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  
  #include <crypto/aead.h>
  #include <linux/highmem.h>
  #include <linux/module.h>
  #include <linux/netdevice.h>
  #include <net/dst.h>
  #include <net/inet_connection_sock.h>
  #include <net/tcp.h>
  #include <net/tls.h>
  
  #include "trace.h"
  
  /* device_offload_lock is used to synchronize tls_dev_add
   * against NETDEV_DOWN notifications.
   */
  static DECLARE_RWSEM(device_offload_lock);
  
  static void tls_device_gc_task(struct work_struct *work);
  
  static DECLARE_WORK(tls_device_gc_work, tls_device_gc_task);
  static LIST_HEAD(tls_device_gc_list);
  static LIST_HEAD(tls_device_list);
  static DEFINE_SPINLOCK(tls_device_lock);
  
  static void tls_device_free_ctx(struct tls_context *ctx)
  {
  	if (ctx->tx_conf == TLS_HW) {
  		kfree(tls_offload_ctx_tx(ctx));
  		kfree(ctx->tx.rec_seq);
  		kfree(ctx->tx.iv);
  	}
  
  	if (ctx->rx_conf == TLS_HW)
  		kfree(tls_offload_ctx_rx(ctx));
  
  	tls_ctx_free(NULL, ctx);
  }
  
  static void tls_device_gc_task(struct work_struct *work)
  {
  	struct tls_context *ctx, *tmp;
  	unsigned long flags;
  	LIST_HEAD(gc_list);
  
  	spin_lock_irqsave(&tls_device_lock, flags);
  	list_splice_init(&tls_device_gc_list, &gc_list);
  	spin_unlock_irqrestore(&tls_device_lock, flags);
  
  	list_for_each_entry_safe(ctx, tmp, &gc_list, list) {
  		struct net_device *netdev = ctx->netdev;
  
  		if (netdev && ctx->tx_conf == TLS_HW) {
  			netdev->tlsdev_ops->tls_dev_del(netdev, ctx,
  							TLS_OFFLOAD_CTX_DIR_TX);
  			dev_put(netdev);
  			ctx->netdev = NULL;
  		}
  
  		list_del(&ctx->list);
  		tls_device_free_ctx(ctx);
  	}
  }
  
  static void tls_device_queue_ctx_destruction(struct tls_context *ctx)
  {
  	unsigned long flags;
  
  	spin_lock_irqsave(&tls_device_lock, flags);
  	list_move_tail(&ctx->list, &tls_device_gc_list);
  
  	/* schedule_work inside the spinlock
  	 * to make sure tls_device_down waits for that work.
  	 */
  	schedule_work(&tls_device_gc_work);
  
  	spin_unlock_irqrestore(&tls_device_lock, flags);
  }
  
  /* We assume that the socket is already connected */
  static struct net_device *get_netdev_for_sock(struct sock *sk)
  {
  	struct dst_entry *dst = sk_dst_get(sk);
  	struct net_device *netdev = NULL;
  
  	if (likely(dst)) {
  		netdev = dst->dev;
  		dev_hold(netdev);
  	}
  
  	dst_release(dst);
  
  	return netdev;
  }
  
  static void destroy_record(struct tls_record_info *record)
  {
  	int i;
  
  	for (i = 0; i < record->num_frags; i++)
  		__skb_frag_unref(&record->frags[i]);
  	kfree(record);
  }
  
  static void delete_all_records(struct tls_offload_context_tx *offload_ctx)
  {
  	struct tls_record_info *info, *temp;
  
  	list_for_each_entry_safe(info, temp, &offload_ctx->records_list, list) {
  		list_del(&info->list);
  		destroy_record(info);
  	}
  
  	offload_ctx->retransmit_hint = NULL;
  }
  
  static void tls_icsk_clean_acked(struct sock *sk, u32 acked_seq)
  {
  	struct tls_context *tls_ctx = tls_get_ctx(sk);
  	struct tls_record_info *info, *temp;
  	struct tls_offload_context_tx *ctx;
  	u64 deleted_records = 0;
  	unsigned long flags;
  
  	if (!tls_ctx)
  		return;
  
  	ctx = tls_offload_ctx_tx(tls_ctx);
  
  	spin_lock_irqsave(&ctx->lock, flags);
  	info = ctx->retransmit_hint;
  	if (info && !before(acked_seq, info->end_seq))
  		ctx->retransmit_hint = NULL;
  
  	list_for_each_entry_safe(info, temp, &ctx->records_list, list) {
  		if (before(acked_seq, info->end_seq))
  			break;
  		list_del(&info->list);
  
  		destroy_record(info);
  		deleted_records++;
  	}
  
  	ctx->unacked_record_sn += deleted_records;
  	spin_unlock_irqrestore(&ctx->lock, flags);
  }
  
  /* At this point, there should be no references on this
   * socket and no in-flight SKBs associated with this
   * socket, so it is safe to free all the resources.
   */
  static void tls_device_sk_destruct(struct sock *sk)
  {
  	struct tls_context *tls_ctx = tls_get_ctx(sk);
  	struct tls_offload_context_tx *ctx = tls_offload_ctx_tx(tls_ctx);
  
  	tls_ctx->sk_destruct(sk);
  
  	if (tls_ctx->tx_conf == TLS_HW) {
  		if (ctx->open_record)
  			destroy_record(ctx->open_record);
  		delete_all_records(ctx);
  		crypto_free_aead(ctx->aead_send);
  		clean_acked_data_disable(inet_csk(sk));
  	}
  
  	if (refcount_dec_and_test(&tls_ctx->refcount))
  		tls_device_queue_ctx_destruction(tls_ctx);
  }
  
  void tls_device_free_resources_tx(struct sock *sk)
  {
  	struct tls_context *tls_ctx = tls_get_ctx(sk);
  
  	tls_free_partial_record(sk, tls_ctx);
  }
  
  void tls_offload_tx_resync_request(struct sock *sk, u32 got_seq, u32 exp_seq)
  {
  	struct tls_context *tls_ctx = tls_get_ctx(sk);
  
  	trace_tls_device_tx_resync_req(sk, got_seq, exp_seq);
  	WARN_ON(test_and_set_bit(TLS_TX_SYNC_SCHED, &tls_ctx->flags));
  }
  EXPORT_SYMBOL_GPL(tls_offload_tx_resync_request);
  
  static void tls_device_resync_tx(struct sock *sk, struct tls_context *tls_ctx,
  				 u32 seq)
  {
  	struct net_device *netdev;
  	struct sk_buff *skb;
  	int err = 0;
  	u8 *rcd_sn;
  
  	skb = tcp_write_queue_tail(sk);
  	if (skb)
  		TCP_SKB_CB(skb)->eor = 1;
  
  	rcd_sn = tls_ctx->tx.rec_seq;
  
  	trace_tls_device_tx_resync_send(sk, seq, rcd_sn);
  	down_read(&device_offload_lock);
  	netdev = tls_ctx->netdev;
  	if (netdev)
  		err = netdev->tlsdev_ops->tls_dev_resync(netdev, sk, seq,
  							 rcd_sn,
  							 TLS_OFFLOAD_CTX_DIR_TX);
  	up_read(&device_offload_lock);
  	if (err)
  		return;
  
  	clear_bit_unlock(TLS_TX_SYNC_SCHED, &tls_ctx->flags);
  }
  
  static void tls_append_frag(struct tls_record_info *record,
  			    struct page_frag *pfrag,
  			    int size)
  {
  	skb_frag_t *frag;
  
  	frag = &record->frags[record->num_frags - 1];
  	if (skb_frag_page(frag) == pfrag->page &&
  	    skb_frag_off(frag) + skb_frag_size(frag) == pfrag->offset) {
  		skb_frag_size_add(frag, size);
  	} else {
  		++frag;
  		__skb_frag_set_page(frag, pfrag->page);
  		skb_frag_off_set(frag, pfrag->offset);
  		skb_frag_size_set(frag, size);
  		++record->num_frags;
  		get_page(pfrag->page);
  	}
  
  	pfrag->offset += size;
  	record->len += size;
  }
  
  static int tls_push_record(struct sock *sk,
  			   struct tls_context *ctx,
  			   struct tls_offload_context_tx *offload_ctx,
  			   struct tls_record_info *record,
  			   int flags)
  {
  	struct tls_prot_info *prot = &ctx->prot_info;
  	struct tcp_sock *tp = tcp_sk(sk);
  	skb_frag_t *frag;
  	int i;
  
  	record->end_seq = tp->write_seq + record->len;
  	list_add_tail_rcu(&record->list, &offload_ctx->records_list);
  	offload_ctx->open_record = NULL;
  
  	if (test_bit(TLS_TX_SYNC_SCHED, &ctx->flags))
  		tls_device_resync_tx(sk, ctx, tp->write_seq);
  
  	tls_advance_record_sn(sk, prot, &ctx->tx);
  
  	for (i = 0; i < record->num_frags; i++) {
  		frag = &record->frags[i];
  		sg_unmark_end(&offload_ctx->sg_tx_data[i]);
  		sg_set_page(&offload_ctx->sg_tx_data[i], skb_frag_page(frag),
  			    skb_frag_size(frag), skb_frag_off(frag));
  		sk_mem_charge(sk, skb_frag_size(frag));
  		get_page(skb_frag_page(frag));
  	}
  	sg_mark_end(&offload_ctx->sg_tx_data[record->num_frags - 1]);
  
  	/* all ready, send */
  	return tls_push_sg(sk, ctx, offload_ctx->sg_tx_data, 0, flags);
  }
  
  static int tls_device_record_close(struct sock *sk,
  				   struct tls_context *ctx,
  				   struct tls_record_info *record,
  				   struct page_frag *pfrag,
  				   unsigned char record_type)
  {
  	struct tls_prot_info *prot = &ctx->prot_info;
  	int ret;
  
  	/* append tag
  	 * device will fill in the tag, we just need to append a placeholder
  	 * use socket memory to improve coalescing (re-using a single buffer
  	 * increases frag count)
  	 * if we can't allocate memory now, steal some back from data
  	 */
  	if (likely(skb_page_frag_refill(prot->tag_size, pfrag,
  					sk->sk_allocation))) {
  		ret = 0;
  		tls_append_frag(record, pfrag, prot->tag_size);
  	} else {
  		ret = prot->tag_size;
  		if (record->len <= prot->overhead_size)
  			return -ENOMEM;
  	}
  
  	/* fill prepend */
  	tls_fill_prepend(ctx, skb_frag_address(&record->frags[0]),
  			 record->len - prot->overhead_size,
  			 record_type, prot->version);
  	return ret;
  }
  
  static int tls_create_new_record(struct tls_offload_context_tx *offload_ctx,
  				 struct page_frag *pfrag,
  				 size_t prepend_size)
  {
  	struct tls_record_info *record;
  	skb_frag_t *frag;
  
  	record = kmalloc(sizeof(*record), GFP_KERNEL);
  	if (!record)
  		return -ENOMEM;
  
  	frag = &record->frags[0];
  	__skb_frag_set_page(frag, pfrag->page);
  	skb_frag_off_set(frag, pfrag->offset);
  	skb_frag_size_set(frag, prepend_size);
  
  	get_page(pfrag->page);
  	pfrag->offset += prepend_size;
  
  	record->num_frags = 1;
  	record->len = prepend_size;
  	offload_ctx->open_record = record;
  	return 0;
  }
  
  static int tls_do_allocation(struct sock *sk,
  			     struct tls_offload_context_tx *offload_ctx,
  			     struct page_frag *pfrag,
  			     size_t prepend_size)
  {
  	int ret;
  
  	if (!offload_ctx->open_record) {
  		if (unlikely(!skb_page_frag_refill(prepend_size, pfrag,
  						   sk->sk_allocation))) {
  			sk->sk_prot->enter_memory_pressure(sk);
  			sk_stream_moderate_sndbuf(sk);
  			return -ENOMEM;
  		}
  
  		ret = tls_create_new_record(offload_ctx, pfrag, prepend_size);
  		if (ret)
  			return ret;
  
  		if (pfrag->size > pfrag->offset)
  			return 0;
  	}
  
  	if (!sk_page_frag_refill(sk, pfrag))
  		return -ENOMEM;
  
  	return 0;
  }
  
  static int tls_device_copy_data(void *addr, size_t bytes, struct iov_iter *i)
  {
  	size_t pre_copy, nocache;
  
  	pre_copy = ~((unsigned long)addr - 1) & (SMP_CACHE_BYTES - 1);
  	if (pre_copy) {
  		pre_copy = min(pre_copy, bytes);
  		if (copy_from_iter(addr, pre_copy, i) != pre_copy)
  			return -EFAULT;
  		bytes -= pre_copy;
  		addr += pre_copy;
  	}
  
  	nocache = round_down(bytes, SMP_CACHE_BYTES);
  	if (copy_from_iter_nocache(addr, nocache, i) != nocache)
  		return -EFAULT;
  	bytes -= nocache;
  	addr += nocache;
  
  	if (bytes && copy_from_iter(addr, bytes, i) != bytes)
  		return -EFAULT;
  
  	return 0;
  }
  
  static int tls_push_data(struct sock *sk,
  			 struct iov_iter *msg_iter,
  			 size_t size, int flags,
  			 unsigned char record_type)
  {
  	struct tls_context *tls_ctx = tls_get_ctx(sk);
  	struct tls_prot_info *prot = &tls_ctx->prot_info;
  	struct tls_offload_context_tx *ctx = tls_offload_ctx_tx(tls_ctx);
  	int more = flags & (MSG_SENDPAGE_NOTLAST | MSG_MORE);
  	struct tls_record_info *record = ctx->open_record;
  	int tls_push_record_flags;
  	struct page_frag *pfrag;
  	size_t orig_size = size;
  	u32 max_open_record_len;
  	int copy, rc = 0;
  	bool done = false;
  	long timeo;
  
  	if (flags &
  	    ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_SENDPAGE_NOTLAST))
  		return -EOPNOTSUPP;
  
  	if (unlikely(sk->sk_err))
  		return -sk->sk_err;
  
  	flags |= MSG_SENDPAGE_DECRYPTED;
  	tls_push_record_flags = flags | MSG_SENDPAGE_NOTLAST;
  
  	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
  	if (tls_is_partially_sent_record(tls_ctx)) {
  		rc = tls_push_partial_record(sk, tls_ctx, flags);
  		if (rc < 0)
  			return rc;
  	}
  
  	pfrag = sk_page_frag(sk);
  
  	/* TLS_HEADER_SIZE is not counted as part of the TLS record, and
  	 * we need to leave room for an authentication tag.
  	 */
  	max_open_record_len = TLS_MAX_PAYLOAD_SIZE +
  			      prot->prepend_size;
  	do {
  		rc = tls_do_allocation(sk, ctx, pfrag, prot->prepend_size);
  		if (unlikely(rc)) {
  			rc = sk_stream_wait_memory(sk, &timeo);
  			if (!rc)
  				continue;
  
  			record = ctx->open_record;
  			if (!record)
  				break;
  handle_error:
  			if (record_type != TLS_RECORD_TYPE_DATA) {
  				/* avoid sending partial
  				 * record with type !=
  				 * application_data
  				 */
  				size = orig_size;
  				destroy_record(record);
  				ctx->open_record = NULL;
  			} else if (record->len > prot->prepend_size) {
  				goto last_record;
  			}
  
  			break;
  		}
  
  		record = ctx->open_record;
  		copy = min_t(size_t, size, (pfrag->size - pfrag->offset));
  		copy = min_t(size_t, copy, (max_open_record_len - record->len));
  
  		rc = tls_device_copy_data(page_address(pfrag->page) +
  					  pfrag->offset, copy, msg_iter);
  		if (rc)
  			goto handle_error;
  		tls_append_frag(record, pfrag, copy);
  
  		size -= copy;
  		if (!size) {
  last_record:
  			tls_push_record_flags = flags;
  			if (more) {
  				tls_ctx->pending_open_record_frags =
  						!!record->num_frags;
  				break;
  			}
  
  			done = true;
  		}
  
  		if (done || record->len >= max_open_record_len ||
  		    (record->num_frags >= MAX_SKB_FRAGS - 1)) {
  			rc = tls_device_record_close(sk, tls_ctx, record,
  						     pfrag, record_type);
  			if (rc) {
  				if (rc > 0) {
  					size += rc;
  				} else {
  					size = orig_size;
  					destroy_record(record);
  					ctx->open_record = NULL;
  					break;
  				}
  			}
  
  			rc = tls_push_record(sk,
  					     tls_ctx,
  					     ctx,
  					     record,
  					     tls_push_record_flags);
  			if (rc < 0)
  				break;
  		}
  	} while (!done);
  
  	if (orig_size - size > 0)
  		rc = orig_size - size;
  
  	return rc;
  }
  
  int tls_device_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
  {
  	unsigned char record_type = TLS_RECORD_TYPE_DATA;
  	struct tls_context *tls_ctx = tls_get_ctx(sk);
  	int rc;
  
  	mutex_lock(&tls_ctx->tx_lock);
  	lock_sock(sk);
  
  	if (unlikely(msg->msg_controllen)) {
  		rc = tls_proccess_cmsg(sk, msg, &record_type);
  		if (rc)
  			goto out;
  	}
  
  	rc = tls_push_data(sk, &msg->msg_iter, size,
  			   msg->msg_flags, record_type);
  
  out:
  	release_sock(sk);
  	mutex_unlock(&tls_ctx->tx_lock);
  	return rc;
  }
  
  int tls_device_sendpage(struct sock *sk, struct page *page,
  			int offset, size_t size, int flags)
  {
  	struct tls_context *tls_ctx = tls_get_ctx(sk);
  	struct iov_iter	msg_iter;
  	char *kaddr = kmap(page);
  	struct kvec iov;
  	int rc;
  
  	if (flags & MSG_SENDPAGE_NOTLAST)
  		flags |= MSG_MORE;
  
  	mutex_lock(&tls_ctx->tx_lock);
  	lock_sock(sk);
  
  	if (flags & MSG_OOB) {
  		rc = -EOPNOTSUPP;
  		goto out;
  	}
  
  	iov.iov_base = kaddr + offset;
  	iov.iov_len = size;
  	iov_iter_kvec(&msg_iter, WRITE, &iov, 1, size);
  	rc = tls_push_data(sk, &msg_iter, size,
  			   flags, TLS_RECORD_TYPE_DATA);
  	kunmap(page);
  
  out:
  	release_sock(sk);
  	mutex_unlock(&tls_ctx->tx_lock);
  	return rc;
  }
  
  struct tls_record_info *tls_get_record(struct tls_offload_context_tx *context,
  				       u32 seq, u64 *p_record_sn)
  {
  	u64 record_sn = context->hint_record_sn;
  	struct tls_record_info *info;
  
  	info = context->retransmit_hint;
  	if (!info ||
  	    before(seq, info->end_seq - info->len)) {
  		/* if retransmit_hint is irrelevant start
  		 * from the beggining of the list
  		 */
  		info = list_first_entry_or_null(&context->records_list,
  						struct tls_record_info, list);
  		if (!info)
  			return NULL;
  		record_sn = context->unacked_record_sn;
  	}
  
  	/* We just need the _rcu for the READ_ONCE() */
  	rcu_read_lock();
  	list_for_each_entry_from_rcu(info, &context->records_list, list) {
  		if (before(seq, info->end_seq)) {
  			if (!context->retransmit_hint ||
  			    after(info->end_seq,
  				  context->retransmit_hint->end_seq)) {
  				context->hint_record_sn = record_sn;
  				context->retransmit_hint = info;
  			}
  			*p_record_sn = record_sn;
  			goto exit_rcu_unlock;
  		}
  		record_sn++;
  	}
  	info = NULL;
  
  exit_rcu_unlock:
  	rcu_read_unlock();
  	return info;
  }
  EXPORT_SYMBOL(tls_get_record);
  
  static int tls_device_push_pending_record(struct sock *sk, int flags)
  {
  	struct iov_iter	msg_iter;
  
  	iov_iter_kvec(&msg_iter, WRITE, NULL, 0, 0);
  	return tls_push_data(sk, &msg_iter, 0, flags, TLS_RECORD_TYPE_DATA);
  }
  
  void tls_device_write_space(struct sock *sk, struct tls_context *ctx)
  {
  	if (tls_is_partially_sent_record(ctx)) {
  		gfp_t sk_allocation = sk->sk_allocation;
  
  		WARN_ON_ONCE(sk->sk_write_pending);
  
  		sk->sk_allocation = GFP_ATOMIC;
  		tls_push_partial_record(sk, ctx,
  					MSG_DONTWAIT | MSG_NOSIGNAL |
  					MSG_SENDPAGE_DECRYPTED);
  		sk->sk_allocation = sk_allocation;
  	}
  }
  
  static void tls_device_resync_rx(struct tls_context *tls_ctx,
  				 struct sock *sk, u32 seq, u8 *rcd_sn)
  {
  	struct tls_offload_context_rx *rx_ctx = tls_offload_ctx_rx(tls_ctx);
  	struct net_device *netdev;
  
  	if (WARN_ON(test_and_set_bit(TLS_RX_SYNC_RUNNING, &tls_ctx->flags)))
  		return;
  
  	trace_tls_device_rx_resync_send(sk, seq, rcd_sn, rx_ctx->resync_type);
  	netdev = READ_ONCE(tls_ctx->netdev);
  	if (netdev)
  		netdev->tlsdev_ops->tls_dev_resync(netdev, sk, seq, rcd_sn,
  						   TLS_OFFLOAD_CTX_DIR_RX);
  	clear_bit_unlock(TLS_RX_SYNC_RUNNING, &tls_ctx->flags);
  	TLS_INC_STATS(sock_net(sk), LINUX_MIB_TLSRXDEVICERESYNC);
  }
  
  void tls_device_rx_resync_new_rec(struct sock *sk, u32 rcd_len, u32 seq)
  {
  	struct tls_context *tls_ctx = tls_get_ctx(sk);
  	struct tls_offload_context_rx *rx_ctx;
  	u8 rcd_sn[TLS_MAX_REC_SEQ_SIZE];
  	u32 sock_data, is_req_pending;
  	struct tls_prot_info *prot;
  	s64 resync_req;
  	u32 req_seq;
  
  	if (tls_ctx->rx_conf != TLS_HW)
  		return;
  
  	prot = &tls_ctx->prot_info;
  	rx_ctx = tls_offload_ctx_rx(tls_ctx);
  	memcpy(rcd_sn, tls_ctx->rx.rec_seq, prot->rec_seq_size);
  
  	switch (rx_ctx->resync_type) {
  	case TLS_OFFLOAD_SYNC_TYPE_DRIVER_REQ:
  		resync_req = atomic64_read(&rx_ctx->resync_req);
  		req_seq = resync_req >> 32;
  		seq += TLS_HEADER_SIZE - 1;
  		is_req_pending = resync_req;
  
  		if (likely(!is_req_pending) || req_seq != seq ||
  		    !atomic64_try_cmpxchg(&rx_ctx->resync_req, &resync_req, 0))
  			return;
  		break;
  	case TLS_OFFLOAD_SYNC_TYPE_CORE_NEXT_HINT:
  		if (likely(!rx_ctx->resync_nh_do_now))
  			return;
  
  		/* head of next rec is already in, note that the sock_inq will
  		 * include the currently parsed message when called from parser
  		 */
  		sock_data = tcp_inq(sk);
  		if (sock_data > rcd_len) {
  			trace_tls_device_rx_resync_nh_delay(sk, sock_data,
  							    rcd_len);
  			return;
  		}
  
  		rx_ctx->resync_nh_do_now = 0;
  		seq += rcd_len;
  		tls_bigint_increment(rcd_sn, prot->rec_seq_size);
  		break;
  	}
  
  	tls_device_resync_rx(tls_ctx, sk, seq, rcd_sn);
  }
  
  static void tls_device_core_ctrl_rx_resync(struct tls_context *tls_ctx,
  					   struct tls_offload_context_rx *ctx,
  					   struct sock *sk, struct sk_buff *skb)
  {
  	struct strp_msg *rxm;
  
  	/* device will request resyncs by itself based on stream scan */
  	if (ctx->resync_type != TLS_OFFLOAD_SYNC_TYPE_CORE_NEXT_HINT)
  		return;
  	/* already scheduled */
  	if (ctx->resync_nh_do_now)
  		return;
  	/* seen decrypted fragments since last fully-failed record */
  	if (ctx->resync_nh_reset) {
  		ctx->resync_nh_reset = 0;
  		ctx->resync_nh.decrypted_failed = 1;
  		ctx->resync_nh.decrypted_tgt = TLS_DEVICE_RESYNC_NH_START_IVAL;
  		return;
  	}
  
  	if (++ctx->resync_nh.decrypted_failed <= ctx->resync_nh.decrypted_tgt)
  		return;
  
  	/* doing resync, bump the next target in case it fails */
  	if (ctx->resync_nh.decrypted_tgt < TLS_DEVICE_RESYNC_NH_MAX_IVAL)
  		ctx->resync_nh.decrypted_tgt *= 2;
  	else
  		ctx->resync_nh.decrypted_tgt += TLS_DEVICE_RESYNC_NH_MAX_IVAL;
  
  	rxm = strp_msg(skb);
  
  	/* head of next rec is already in, parser will sync for us */
  	if (tcp_inq(sk) > rxm->full_len) {
  		trace_tls_device_rx_resync_nh_schedule(sk);
  		ctx->resync_nh_do_now = 1;
  	} else {
  		struct tls_prot_info *prot = &tls_ctx->prot_info;
  		u8 rcd_sn[TLS_MAX_REC_SEQ_SIZE];
  
  		memcpy(rcd_sn, tls_ctx->rx.rec_seq, prot->rec_seq_size);
  		tls_bigint_increment(rcd_sn, prot->rec_seq_size);
  
  		tls_device_resync_rx(tls_ctx, sk, tcp_sk(sk)->copied_seq,
  				     rcd_sn);
  	}
  }
  
  static int tls_device_reencrypt(struct sock *sk, struct sk_buff *skb)
  {
  	struct strp_msg *rxm = strp_msg(skb);
  	int err = 0, offset = rxm->offset, copy, nsg, data_len, pos;
  	struct sk_buff *skb_iter, *unused;
  	struct scatterlist sg[1];
  	char *orig_buf, *buf;
  
  	orig_buf = kmalloc(rxm->full_len + TLS_HEADER_SIZE +
  			   TLS_CIPHER_AES_GCM_128_IV_SIZE, sk->sk_allocation);
  	if (!orig_buf)
  		return -ENOMEM;
  	buf = orig_buf;
  
  	nsg = skb_cow_data(skb, 0, &unused);
  	if (unlikely(nsg < 0)) {
  		err = nsg;
  		goto free_buf;
  	}
  
  	sg_init_table(sg, 1);
  	sg_set_buf(&sg[0], buf,
  		   rxm->full_len + TLS_HEADER_SIZE +
  		   TLS_CIPHER_AES_GCM_128_IV_SIZE);
  	err = skb_copy_bits(skb, offset, buf,
  			    TLS_HEADER_SIZE + TLS_CIPHER_AES_GCM_128_IV_SIZE);
  	if (err)
  		goto free_buf;
  
  	/* We are interested only in the decrypted data not the auth */
  	err = decrypt_skb(sk, skb, sg);
  	if (err != -EBADMSG)
  		goto free_buf;
  	else
  		err = 0;
  
  	data_len = rxm->full_len - TLS_CIPHER_AES_GCM_128_TAG_SIZE;
  
  	if (skb_pagelen(skb) > offset) {
  		copy = min_t(int, skb_pagelen(skb) - offset, data_len);
  
  		if (skb->decrypted) {
  			err = skb_store_bits(skb, offset, buf, copy);
  			if (err)
  				goto free_buf;
  		}
  
  		offset += copy;
  		buf += copy;
  	}
  
  	pos = skb_pagelen(skb);
  	skb_walk_frags(skb, skb_iter) {
  		int frag_pos;
  
  		/* Practically all frags must belong to msg if reencrypt
  		 * is needed with current strparser and coalescing logic,
  		 * but strparser may "get optimized", so let's be safe.
  		 */
  		if (pos + skb_iter->len <= offset)
  			goto done_with_frag;
  		if (pos >= data_len + rxm->offset)
  			break;
  
  		frag_pos = offset - pos;
  		copy = min_t(int, skb_iter->len - frag_pos,
  			     data_len + rxm->offset - offset);
  
  		if (skb_iter->decrypted) {
  			err = skb_store_bits(skb_iter, frag_pos, buf, copy);
  			if (err)
  				goto free_buf;
  		}
  
  		offset += copy;
  		buf += copy;
  done_with_frag:
  		pos += skb_iter->len;
  	}
  
  free_buf:
  	kfree(orig_buf);
  	return err;
  }
  
  int tls_device_decrypted(struct sock *sk, struct tls_context *tls_ctx,
  			 struct sk_buff *skb, struct strp_msg *rxm)
  {
  	struct tls_offload_context_rx *ctx = tls_offload_ctx_rx(tls_ctx);
  	int is_decrypted = skb->decrypted;
  	int is_encrypted = !is_decrypted;
  	struct sk_buff *skb_iter;
  
  	/* Check if all the data is decrypted already */
  	skb_walk_frags(skb, skb_iter) {
  		is_decrypted &= skb_iter->decrypted;
  		is_encrypted &= !skb_iter->decrypted;
  	}
  
  	trace_tls_device_decrypted(sk, tcp_sk(sk)->copied_seq - rxm->full_len,
  				   tls_ctx->rx.rec_seq, rxm->full_len,
  				   is_encrypted, is_decrypted);
  
  	ctx->sw.decrypted |= is_decrypted;
  
  	/* Return immediately if the record is either entirely plaintext or
  	 * entirely ciphertext. Otherwise handle reencrypt partially decrypted
  	 * record.
  	 */
  	if (is_decrypted) {
  		ctx->resync_nh_reset = 1;
  		return 0;
  	}
  	if (is_encrypted) {
  		tls_device_core_ctrl_rx_resync(tls_ctx, ctx, sk, skb);
  		return 0;
  	}
  
  	ctx->resync_nh_reset = 1;
  	return tls_device_reencrypt(sk, skb);
  }
  
  static void tls_device_attach(struct tls_context *ctx, struct sock *sk,
  			      struct net_device *netdev)
  {
  	if (sk->sk_destruct != tls_device_sk_destruct) {
  		refcount_set(&ctx->refcount, 1);
  		dev_hold(netdev);
  		ctx->netdev = netdev;
  		spin_lock_irq(&tls_device_lock);
  		list_add_tail(&ctx->list, &tls_device_list);
  		spin_unlock_irq(&tls_device_lock);
  
  		ctx->sk_destruct = sk->sk_destruct;
  		sk->sk_destruct = tls_device_sk_destruct;
  	}
  }
  
  int tls_set_device_offload(struct sock *sk, struct tls_context *ctx)
  {
  	u16 nonce_size, tag_size, iv_size, rec_seq_size;
  	struct tls_context *tls_ctx = tls_get_ctx(sk);
  	struct tls_prot_info *prot = &tls_ctx->prot_info;
  	struct tls_record_info *start_marker_record;
  	struct tls_offload_context_tx *offload_ctx;
  	struct tls_crypto_info *crypto_info;
  	struct net_device *netdev;
  	char *iv, *rec_seq;
  	struct sk_buff *skb;
  	__be64 rcd_sn;
  	int rc;
  
  	if (!ctx)
  		return -EINVAL;
  
  	if (ctx->priv_ctx_tx)
  		return -EEXIST;
  
  	start_marker_record = kmalloc(sizeof(*start_marker_record), GFP_KERNEL);
  	if (!start_marker_record)
  		return -ENOMEM;
  
  	offload_ctx = kzalloc(TLS_OFFLOAD_CONTEXT_SIZE_TX, GFP_KERNEL);
  	if (!offload_ctx) {
  		rc = -ENOMEM;
  		goto free_marker_record;
  	}
  
  	crypto_info = &ctx->crypto_send.info;
  	if (crypto_info->version != TLS_1_2_VERSION) {
  		rc = -EOPNOTSUPP;
  		goto free_offload_ctx;
  	}
  
  	switch (crypto_info->cipher_type) {
  	case TLS_CIPHER_AES_GCM_128:
  		nonce_size = TLS_CIPHER_AES_GCM_128_IV_SIZE;
  		tag_size = TLS_CIPHER_AES_GCM_128_TAG_SIZE;
  		iv_size = TLS_CIPHER_AES_GCM_128_IV_SIZE;
  		iv = ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->iv;
  		rec_seq_size = TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE;
  		rec_seq =
  		 ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->rec_seq;
  		break;
  	default:
  		rc = -EINVAL;
  		goto free_offload_ctx;
  	}
  
  	/* Sanity-check the rec_seq_size for stack allocations */
  	if (rec_seq_size > TLS_MAX_REC_SEQ_SIZE) {
  		rc = -EINVAL;
  		goto free_offload_ctx;
  	}
  
  	prot->version = crypto_info->version;
  	prot->cipher_type = crypto_info->cipher_type;
  	prot->prepend_size = TLS_HEADER_SIZE + nonce_size;
  	prot->tag_size = tag_size;
  	prot->overhead_size = prot->prepend_size + prot->tag_size;
  	prot->iv_size = iv_size;
  	ctx->tx.iv = kmalloc(iv_size + TLS_CIPHER_AES_GCM_128_SALT_SIZE,
  			     GFP_KERNEL);
  	if (!ctx->tx.iv) {
  		rc = -ENOMEM;
  		goto free_offload_ctx;
  	}
  
  	memcpy(ctx->tx.iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE, iv, iv_size);
  
  	prot->rec_seq_size = rec_seq_size;
  	ctx->tx.rec_seq = kmemdup(rec_seq, rec_seq_size, GFP_KERNEL);
  	if (!ctx->tx.rec_seq) {
  		rc = -ENOMEM;
  		goto free_iv;
  	}
  
  	rc = tls_sw_fallback_init(sk, offload_ctx, crypto_info);
  	if (rc)
  		goto free_rec_seq;
  
  	/* start at rec_seq - 1 to account for the start marker record */
  	memcpy(&rcd_sn, ctx->tx.rec_seq, sizeof(rcd_sn));
  	offload_ctx->unacked_record_sn = be64_to_cpu(rcd_sn) - 1;
  
  	start_marker_record->end_seq = tcp_sk(sk)->write_seq;
  	start_marker_record->len = 0;
  	start_marker_record->num_frags = 0;
  
  	INIT_LIST_HEAD(&offload_ctx->records_list);
  	list_add_tail(&start_marker_record->list, &offload_ctx->records_list);
  	spin_lock_init(&offload_ctx->lock);
  	sg_init_table(offload_ctx->sg_tx_data,
  		      ARRAY_SIZE(offload_ctx->sg_tx_data));
  
  	clean_acked_data_enable(inet_csk(sk), &tls_icsk_clean_acked);
  	ctx->push_pending_record = tls_device_push_pending_record;
  
  	/* TLS offload is greatly simplified if we don't send
  	 * SKBs where only part of the payload needs to be encrypted.
  	 * So mark the last skb in the write queue as end of record.
  	 */
  	skb = tcp_write_queue_tail(sk);
  	if (skb)
  		TCP_SKB_CB(skb)->eor = 1;
  
  	netdev = get_netdev_for_sock(sk);
  	if (!netdev) {
  		pr_err_ratelimited("%s: netdev not found\n", __func__);
  		rc = -EINVAL;
  		goto disable_cad;
  	}
  
  	if (!(netdev->features & NETIF_F_HW_TLS_TX)) {
  		rc = -EOPNOTSUPP;
  		goto release_netdev;
  	}
  
  	/* Avoid offloading if the device is down
  	 * We don't want to offload new flows after
  	 * the NETDEV_DOWN event
  	 *
  	 * device_offload_lock is taken in tls_devices's NETDEV_DOWN
  	 * handler thus protecting from the device going down before
  	 * ctx was added to tls_device_list.
  	 */
  	down_read(&device_offload_lock);
  	if (!(netdev->flags & IFF_UP)) {
  		rc = -EINVAL;
  		goto release_lock;
  	}
  
  	ctx->priv_ctx_tx = offload_ctx;
  	rc = netdev->tlsdev_ops->tls_dev_add(netdev, sk, TLS_OFFLOAD_CTX_DIR_TX,
  					     &ctx->crypto_send.info,
  					     tcp_sk(sk)->write_seq);
  	trace_tls_device_offload_set(sk, TLS_OFFLOAD_CTX_DIR_TX,
  				     tcp_sk(sk)->write_seq, rec_seq, rc);
  	if (rc)
  		goto release_lock;
  
  	tls_device_attach(ctx, sk, netdev);
  	up_read(&device_offload_lock);
  
  	/* following this assignment tls_is_sk_tx_device_offloaded
  	 * will return true and the context might be accessed
  	 * by the netdev's xmit function.
  	 */
  	smp_store_release(&sk->sk_validate_xmit_skb, tls_validate_xmit_skb);
  	dev_put(netdev);
  
  	return 0;
  
  release_lock:
  	up_read(&device_offload_lock);
  release_netdev:
  	dev_put(netdev);
  disable_cad:
  	clean_acked_data_disable(inet_csk(sk));
  	crypto_free_aead(offload_ctx->aead_send);
  free_rec_seq:
  	kfree(ctx->tx.rec_seq);
  free_iv:
  	kfree(ctx->tx.iv);
  free_offload_ctx:
  	kfree(offload_ctx);
  	ctx->priv_ctx_tx = NULL;
  free_marker_record:
  	kfree(start_marker_record);
  	return rc;
  }
  
  int tls_set_device_offload_rx(struct sock *sk, struct tls_context *ctx)
  {
  	struct tls12_crypto_info_aes_gcm_128 *info;
  	struct tls_offload_context_rx *context;
  	struct net_device *netdev;
  	int rc = 0;
  
  	if (ctx->crypto_recv.info.version != TLS_1_2_VERSION)
  		return -EOPNOTSUPP;
  
  	netdev = get_netdev_for_sock(sk);
  	if (!netdev) {
  		pr_err_ratelimited("%s: netdev not found\n", __func__);
  		return -EINVAL;
  	}
  
  	if (!(netdev->features & NETIF_F_HW_TLS_RX)) {
  		rc = -EOPNOTSUPP;
  		goto release_netdev;
  	}
  
  	/* Avoid offloading if the device is down
  	 * We don't want to offload new flows after
  	 * the NETDEV_DOWN event
  	 *
  	 * device_offload_lock is taken in tls_devices's NETDEV_DOWN
  	 * handler thus protecting from the device going down before
  	 * ctx was added to tls_device_list.
  	 */
  	down_read(&device_offload_lock);
  	if (!(netdev->flags & IFF_UP)) {
  		rc = -EINVAL;
  		goto release_lock;
  	}
  
  	context = kzalloc(TLS_OFFLOAD_CONTEXT_SIZE_RX, GFP_KERNEL);
  	if (!context) {
  		rc = -ENOMEM;
  		goto release_lock;
  	}
  	context->resync_nh_reset = 1;
  
  	ctx->priv_ctx_rx = context;
  	rc = tls_set_sw_offload(sk, ctx, 0);
  	if (rc)
  		goto release_ctx;
  
  	rc = netdev->tlsdev_ops->tls_dev_add(netdev, sk, TLS_OFFLOAD_CTX_DIR_RX,
  					     &ctx->crypto_recv.info,
  					     tcp_sk(sk)->copied_seq);
  	info = (void *)&ctx->crypto_recv.info;
  	trace_tls_device_offload_set(sk, TLS_OFFLOAD_CTX_DIR_RX,
  				     tcp_sk(sk)->copied_seq, info->rec_seq, rc);
  	if (rc)
  		goto free_sw_resources;
  
  	tls_device_attach(ctx, sk, netdev);
  	up_read(&device_offload_lock);
  
  	dev_put(netdev);
  
  	return 0;
  
  free_sw_resources:
  	up_read(&device_offload_lock);
  	tls_sw_free_resources_rx(sk);
  	down_read(&device_offload_lock);
  release_ctx:
  	ctx->priv_ctx_rx = NULL;
  release_lock:
  	up_read(&device_offload_lock);
  release_netdev:
  	dev_put(netdev);
  	return rc;
  }
  
  void tls_device_offload_cleanup_rx(struct sock *sk)
  {
  	struct tls_context *tls_ctx = tls_get_ctx(sk);
  	struct net_device *netdev;
  
  	down_read(&device_offload_lock);
  	netdev = tls_ctx->netdev;
  	if (!netdev)
  		goto out;
  
  	netdev->tlsdev_ops->tls_dev_del(netdev, tls_ctx,
  					TLS_OFFLOAD_CTX_DIR_RX);
  
  	if (tls_ctx->tx_conf != TLS_HW) {
  		dev_put(netdev);
  		tls_ctx->netdev = NULL;
  	}
  out:
  	up_read(&device_offload_lock);
  	tls_sw_release_resources_rx(sk);
  }
  
  static int tls_device_down(struct net_device *netdev)
  {
  	struct tls_context *ctx, *tmp;
  	unsigned long flags;
  	LIST_HEAD(list);
  
  	/* Request a write lock to block new offload attempts */
  	down_write(&device_offload_lock);
  
  	spin_lock_irqsave(&tls_device_lock, flags);
  	list_for_each_entry_safe(ctx, tmp, &tls_device_list, list) {
  		if (ctx->netdev != netdev ||
  		    !refcount_inc_not_zero(&ctx->refcount))
  			continue;
  
  		list_move(&ctx->list, &list);
  	}
  	spin_unlock_irqrestore(&tls_device_lock, flags);
  
  	list_for_each_entry_safe(ctx, tmp, &list, list)	{
  		if (ctx->tx_conf == TLS_HW)
  			netdev->tlsdev_ops->tls_dev_del(netdev, ctx,
  							TLS_OFFLOAD_CTX_DIR_TX);
  		if (ctx->rx_conf == TLS_HW)
  			netdev->tlsdev_ops->tls_dev_del(netdev, ctx,
  							TLS_OFFLOAD_CTX_DIR_RX);
  		WRITE_ONCE(ctx->netdev, NULL);
  		smp_mb__before_atomic(); /* pairs with test_and_set_bit() */
  		while (test_bit(TLS_RX_SYNC_RUNNING, &ctx->flags))
  			usleep_range(10, 200);
  		dev_put(netdev);
  		list_del_init(&ctx->list);
  
  		if (refcount_dec_and_test(&ctx->refcount))
  			tls_device_free_ctx(ctx);
  	}
  
  	up_write(&device_offload_lock);
  
  	flush_work(&tls_device_gc_work);
  
  	return NOTIFY_DONE;
  }
  
  static int tls_dev_event(struct notifier_block *this, unsigned long event,
  			 void *ptr)
  {
  	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
  
  	if (!dev->tlsdev_ops &&
  	    !(dev->features & (NETIF_F_HW_TLS_RX | NETIF_F_HW_TLS_TX)))
  		return NOTIFY_DONE;
  
  	switch (event) {
  	case NETDEV_REGISTER:
  	case NETDEV_FEAT_CHANGE:
  		if ((dev->features & NETIF_F_HW_TLS_RX) &&
  		    !dev->tlsdev_ops->tls_dev_resync)
  			return NOTIFY_BAD;
  
  		if  (dev->tlsdev_ops &&
  		     dev->tlsdev_ops->tls_dev_add &&
  		     dev->tlsdev_ops->tls_dev_del)
  			return NOTIFY_DONE;
  		else
  			return NOTIFY_BAD;
  	case NETDEV_DOWN:
  		return tls_device_down(dev);
  	}
  	return NOTIFY_DONE;
  }
  
  static struct notifier_block tls_dev_notifier = {
  	.notifier_call	= tls_dev_event,
  };
  
  void __init tls_device_init(void)
  {
  	register_netdevice_notifier(&tls_dev_notifier);
  }
  
  void __exit tls_device_cleanup(void)
  {
  	unregister_netdevice_notifier(&tls_dev_notifier);
  	flush_work(&tls_device_gc_work);
  	clean_acked_data_flush();
  }
  