Re: [PATCH v3 net-next 6/6] tls: Add generic NIC offload infrastructure.

[Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>]

On Mon, Dec 18, 2017 at 01:10:33PM +0200, Ilya Lesokhin wrote:
> This patch adds a generic infrastructure to offload TLS crypto to a
> network devices. It enables the kernel TLS socket to skip encryption
> and authentication operations on the transmit side of the data path.
> Leaving those computationally expensive operations to the NIC.

I have a hard time understanding why this was named 'tls_device' if no
net_device's are registered.

> 
> The NIC offload infrastructure builds TLS records and pushes them to
> the TCP layer just like the SW KTLS implementation and using the same API.
> TCP segmentation is mostly unaffected. Currently the only exception is
> that we prevent mixed SKBs where only part of the payload requires
> offload. In the future we are likely to add a similar restriction
> following a change cipher spec record.
> 
> The notable differences between SW KTLS and NIC offloaded TLS
> implementations are as follows:
> 1. The offloaded implementation builds "plaintext TLS record", those
> records contain plaintext instead of ciphertext and place holder bytes
> instead of authentication tags.
> 2. The offloaded implementation maintains a mapping from TCP sequence
> number to TLS records. Thus given a TCP SKB sent from a NIC offloaded
> TLS socket, we can use the tls NIC offload infrastructure to obtain
> enough context to encrypt the payload of the SKB.
> A TLS record is released when the last byte of the record is ack'ed,
> this is done through the new icsk_clean_acked callback.
> 
> The infrastructure should be extendable to support various NIC offload
> implementations.  However it is currently written with the
> implementation below in mind:
> The NIC assumes that packets from each offloaded stream are sent as
> plaintext and in-order. It keeps track of the TLS records in the TCP
> stream. When a packet marked for offload is transmitted, the NIC
> encrypts the payload in-place and puts authentication tags in the
> relevant place holders.
> 
> The responsibility for handling out-of-order packets (i.e. TCP
> retransmission, qdisc drops) falls on the netdev driver.
> 
> The netdev driver keeps track of the expected TCP SN from the NIC's
> perspective.  If the next packet to transmit matches the expected TCP
> SN, the driver advances the expected TCP SN, and transmits the packet
> with TLS offload indication.
> 
> If the next packet to transmit does not match the expected TCP SN. The
> driver calls the TLS layer to obtain the TLS record that includes the
> TCP of the packet for transmission. Using this TLS record, the driver
> posts a work entry on the transmit queue to reconstruct the NIC TLS
> state required for the offload of the out-of-order packet. It updates
> the expected TCP SN accordingly and transmit the now in-order packet.
> The same queue is used for packet transmission and TLS context
> reconstruction to avoid the need for flushing the transmit queue before
> issuing the context reconstruction request.
> 
> Signed-off-by: Boris Pismenny <borisp@mellanox.com>
> Signed-off-by: Ilya Lesokhin <ilyal@mellanox.com>
> Signed-off-by: Aviad Yehezkel <aviadye@mellanox.com>
> ---
>  include/net/tls.h             |  62 +++-
>  net/tls/Kconfig               |   9 +
>  net/tls/Makefile              |   3 +
>  net/tls/tls_device.c          | 800 ++++++++++++++++++++++++++++++++++++++++++
>  net/tls/tls_device_fallback.c | 405 +++++++++++++++++++++
>  net/tls/tls_main.c            |  33 +-
>  6 files changed, 1305 insertions(+), 7 deletions(-)
>  create mode 100644 net/tls/tls_device.c
>  create mode 100644 net/tls/tls_device_fallback.c
> 
> diff --git a/include/net/tls.h b/include/net/tls.h
> index 936cfc5cab7d..9c1b5d13d9a7 100644
> --- a/include/net/tls.h
> +++ b/include/net/tls.h
> @@ -75,6 +75,29 @@ struct tls_sw_context {
>  	struct scatterlist sg_aead_out[2];
>  };
>  
> +struct tls_record_info {
> +	struct list_head list;
> +	u32 end_seq;
> +	int len;
> +	int num_frags;
> +	skb_frag_t frags[MAX_SKB_FRAGS];
> +};
> +
> +struct tls_offload_context {
> +	struct crypto_aead *aead_send;
> +
> +	struct list_head records_list;
> +	struct scatterlist sg_tx_data[MAX_SKB_FRAGS];
> +	void (*sk_destruct)(struct sock *sk);
> +	struct tls_record_info *open_record;
> +	struct tls_record_info *retransmit_hint;
> +	u64 hint_record_sn;
> +	u64 unacked_record_sn;
> +
> +	u32 expected_seq;
> +	spinlock_t lock;	/* protects records list */
> +};
> +
>  enum {
>  	TLS_PENDING_CLOSED_RECORD
>  };
> @@ -85,6 +108,10 @@ struct tls_context {
>  		struct tls12_crypto_info_aes_gcm_128 crypto_send_aes_gcm_128;
>  	};
>  
> +	struct list_head list;
> +	struct net_device *netdev;
> +	refcount_t refcount;
> +
>  	void *priv_ctx;
>  
>  	u8 tx_conf:2;
> @@ -129,9 +156,29 @@ int tls_sw_sendpage(struct sock *sk, struct page *page,
>  void tls_sw_close(struct sock *sk, long timeout);
>  void tls_sw_free_tx_resources(struct sock *sk);
>  
> -void tls_sk_destruct(struct sock *sk, struct tls_context *ctx);
> -void tls_icsk_clean_acked(struct sock *sk);
> +void tls_clear_device_offload(struct sock *sk, struct tls_context *ctx);
> +int tls_set_device_offload(struct sock *sk, struct tls_context *ctx);
> +int tls_device_sendmsg(struct sock *sk, struct msghdr *msg, size_t size);
> +int tls_device_sendpage(struct sock *sk, struct page *page,
> +			int offset, size_t size, int flags);
> +void tls_device_sk_destruct(struct sock *sk);
> +void tls_device_init(void);
> +void tls_device_cleanup(void);
>  
> +struct tls_record_info *tls_get_record(struct tls_offload_context *context,
> +				       u32 seq, u64 *p_record_sn);
> +
> +static inline bool tls_record_is_start_marker(struct tls_record_info *rec)
> +{
> +	return rec->len == 0;
> +}
> +
> +static inline u32 tls_record_start_seq(struct tls_record_info *rec)
> +{
> +	return rec->end_seq - rec->len;
> +}
> +
> +void tls_sk_destruct(struct sock *sk, struct tls_context *ctx);
>  int tls_push_sg(struct sock *sk, struct tls_context *ctx,
>  		struct scatterlist *sg, u16 first_offset,
>  		int flags);
> @@ -168,6 +215,13 @@ static inline bool tls_is_pending_open_record(struct tls_context *tls_ctx)
>  	return tls_ctx->pending_open_record_frags;
>  }
>  
> +static inline bool tls_is_sk_tx_device_offloaded(struct sock *sk)
> +{
> +	return sk_fullsock(sk) &&
> +	       /* matches smp_store_release in tls_set_device_offload */
> +	       smp_load_acquire(&sk->sk_destruct) == &tls_device_sk_destruct;
> +}
> +
>  static inline void tls_err_abort(struct sock *sk)
>  {
>  	sk->sk_err = -EBADMSG;
> @@ -255,4 +309,8 @@ static inline struct tls_offload_context *tls_offload_ctx(
>  int tls_proccess_cmsg(struct sock *sk, struct msghdr *msg,
>  		      unsigned char *record_type);
>  
> +int tls_sw_fallback_init(struct sock *sk,
> +			 struct tls_offload_context *offload_ctx,
> +			 struct tls_crypto_info *crypto_info);
> +
>  #endif /* _TLS_OFFLOAD_H */
> diff --git a/net/tls/Kconfig b/net/tls/Kconfig
> index eb583038c67e..1a4ea55c2f09 100644
> --- a/net/tls/Kconfig
> +++ b/net/tls/Kconfig
> @@ -13,3 +13,12 @@ config TLS
>  	encryption handling of the TLS protocol to be done in-kernel.
>  
>  	If unsure, say N.
> +
> +config TLS_DEVICE
> +	bool "Transport Layer Security HW offload"
> +	depends on TLS
> +	default n
> +	---help---
> +	Enable kernel support for HW offload of the TLS protocol.
> +
> +	If unsure, say N.
> diff --git a/net/tls/Makefile b/net/tls/Makefile
> index a930fd1c4f7b..44483cd47b3a 100644
> --- a/net/tls/Makefile
> +++ b/net/tls/Makefile
> @@ -5,3 +5,6 @@
>  obj-$(CONFIG_TLS) += tls.o
>  
>  tls-y := tls_main.o tls_sw.o
> +
> +tls-$(CONFIG_TLS_DEVICE) += tls_device.o tls_device_fallback.o
> +
> diff --git a/net/tls/tls_device.c b/net/tls/tls_device.c
> new file mode 100644
> index 000000000000..5082d693a503
> --- /dev/null
> +++ b/net/tls/tls_device.c
> @@ -0,0 +1,800 @@
> +/* Copyright (c) 2016-2017, Mellanox Technologies All rights reserved.
> + *
> + *     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.
> + *
> + *      - Neither the name of the Mellanox Technologies nor the
> + *        names of its contributors may be used to endorse or promote
> + *        products derived from this software without specific prior written
> + *        permission.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
> + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
> + * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
> + * A PARTICULAR PURPOSE ARE DISCLAIMED.
> + * IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
> + * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
> + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
> + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
> + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
> + * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
> + * POSSIBILITY OF SUCH DAMAGE
> + */
> +
> +#include <linux/module.h>
> +#include <net/tcp.h>
> +#include <net/inet_common.h>
> +#include <linux/highmem.h>
> +#include <linux/netdevice.h>
> +
> +#include <net/tls.h>
> +#include <crypto/aead.h>
> +
> +/* device_offload_lock is used to synchronize tls_dev_add
> + * against NETDEV_DOWN notifications.
> + */
> +DEFINE_STATIC_PERCPU_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)
> +{
> +	struct tls_offload_context *offlad_ctx = tls_offload_ctx(ctx);
> +
> +	kfree(offlad_ctx);
> +	kfree(ctx);
> +}
> +
> +static void tls_device_gc_task(struct work_struct *work)
> +{
> +	struct tls_context *ctx, *tmp;
> +	struct list_head gc_list;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&tls_device_lock, flags);
> +	INIT_LIST_HEAD(&gc_list);
> +	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) {
> +			netdev->tlsdev_ops->tls_dev_del(netdev, ctx,
> +							TLS_OFFLOAD_CTX_DIR_TX);
> +			dev_put(netdev);
> +		}
> +
> +		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 inet_sock *inet = inet_sk(sk);
> +	struct net_device *netdev = NULL;
> +
> +	netdev = dev_get_by_index(sock_net(sk), inet->cork.fl.flowi_oif);
> +
> +	return netdev;
> +}
> +
> +static int attach_sock_to_netdev(struct sock *sk, struct net_device *netdev,
> +				 struct tls_context *ctx)
> +{
> +	int rc;
> +
> +	rc = netdev->tlsdev_ops->tls_dev_add(netdev, sk, TLS_OFFLOAD_CTX_DIR_TX,
> +					     &ctx->crypto_send);
> +	if (rc) {
> +		pr_err("The netdev has refused to offload this socket\n");

_ratelimit here is probably welcomed, as this could be triggered by
users at will.

> +		goto out;
> +	}
> +
> +	rc = 0;
> +out:
> +	return rc;
> +}
> +
> +static void destroy_record(struct tls_record_info *record)
> +{
> +	skb_frag_t *frag;
> +	int nr_frags = record->num_frags;
> +
> +	while (nr_frags > 0) {
> +		frag = &record->frags[nr_frags - 1];
> +		__skb_frag_unref(frag);
> +		--nr_frags;
> +	}
> +	kfree(record);
> +}
> +
> +static void delete_all_records(struct tls_offload_context *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)
> +{
> +	struct tls_context *tls_ctx = tls_get_ctx(sk);
> +	struct tls_offload_context *ctx;
> +	struct tcp_sock *tp = tcp_sk(sk);
> +	struct tls_record_info *info, *temp;
> +	unsigned long flags;
> +	u64 deleted_records = 0;
> +
> +	if (!tls_ctx)
> +		return;
> +
> +	ctx = tls_offload_ctx(tls_ctx);
> +
> +	spin_lock_irqsave(&ctx->lock, flags);

Would be nice if this spinlock could be avoided somehow, as it's being
called right from tcp_ack().

> +	info = ctx->retransmit_hint;
> +	if (info && !before(tp->snd_una, info->end_seq)) {
> +		ctx->retransmit_hint = NULL;
> +		list_del(&info->list);
> +		destroy_record(info);
> +		deleted_records++;
> +	}
> +
> +	list_for_each_entry_safe(info, temp, &ctx->records_list, list) {
> +		if (before(tp->snd_una, 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.
> + */
> +void tls_device_sk_destruct(struct sock *sk)
> +{
> +	struct tls_context *tls_ctx = tls_get_ctx(sk);
> +	struct tls_offload_context *ctx = tls_offload_ctx(tls_ctx);
> +
> +	if (ctx->open_record)
> +		destroy_record(ctx->open_record);
> +
> +	delete_all_records(ctx);
> +	crypto_free_aead(ctx->aead_send);
> +	ctx->sk_destruct(sk);
> +
> +	if (refcount_dec_and_test(&tls_ctx->refcount))
> +		tls_device_queue_ctx_destruction(tls_ctx);
> +}
> +EXPORT_SYMBOL(tls_device_sk_destruct);
> +
> +static inline 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 (frag->page.p == pfrag->page &&
> +	    frag->page_offset + frag->size == pfrag->offset) {
> +		frag->size += size;
> +	} else {
> +		++frag;
> +		frag->page.p = pfrag->page;
> +		frag->page_offset = pfrag->offset;
> +		frag->size = size;
> +		++record->num_frags;
> +		get_page(pfrag->page);
> +	}
> +
> +	pfrag->offset += size;
> +	record->len += size;
> +}
> +
> +static inline int tls_push_record(struct sock *sk,
> +				  struct tls_context *ctx,
> +				  struct tls_offload_context *offload_ctx,
> +				  struct tls_record_info *record,
> +				  struct page_frag *pfrag,
> +				  int flags,
> +				  unsigned char record_type)
> +{
> +	skb_frag_t *frag;
> +	struct tcp_sock *tp = tcp_sk(sk);
> +	struct page_frag fallback_frag;
> +	struct page_frag  *tag_pfrag = pfrag;
> +	int i;
> +
> +	/* fill prepand */
> +	frag = &record->frags[0];
> +	tls_fill_prepend(ctx,
> +			 skb_frag_address(frag),
> +			 record->len - ctx->prepend_size,
> +			 record_type);
> +
> +	if (unlikely(!skb_page_frag_refill(ctx->tag_size, pfrag, GFP_KERNEL))) {
> +		/* HW doesn't care about the data in the tag
> +		 * so in case pfrag has no room
> +		 * for a tag and we can't allocate a new pfrag
> +		 * just use the page in the first frag
> +		 * rather then write a complicated fall back code.
> +		 */
> +		tag_pfrag = &fallback_frag;
> +		tag_pfrag->page = skb_frag_page(frag);
> +		tag_pfrag->offset = 0;
> +	}
> +
> +	tls_append_frag(record, tag_pfrag, ctx->tag_size);
> +	record->end_seq = tp->write_seq + record->len;
> +	spin_lock_irq(&offload_ctx->lock);
> +	list_add_tail(&record->list, &offload_ctx->records_list);
> +	spin_unlock_irq(&offload_ctx->lock);
> +	offload_ctx->open_record = NULL;
> +	set_bit(TLS_PENDING_CLOSED_RECORD, &ctx->flags);
> +	tls_advance_record_sn(sk, ctx);
> +
> +	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),
> +			    frag->size, frag->page_offset);
> +		sk_mem_charge(sk, frag->size);
> +		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 inline int tls_create_new_record(struct tls_offload_context *offload_ctx,
> +					struct page_frag *pfrag,
> +					size_t prepend_size)
> +{
> +	skb_frag_t *frag;
> +	struct tls_record_info *record;
> +
> +	record = kmalloc(sizeof(*record), GFP_KERNEL);
> +	if (!record)
> +		return -ENOMEM;
> +
> +	frag = &record->frags[0];
> +	__skb_frag_set_page(frag, pfrag->page);
> +	frag->page_offset = 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 inline int tls_do_allocation(struct sock *sk,
> +				    struct tls_offload_context *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_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_offload_context *ctx = tls_offload_ctx(tls_ctx);
> +	struct tls_record_info *record = ctx->open_record;
> +	struct page_frag *pfrag;
> +	int copy, rc = 0;
> +	size_t orig_size = size;
> +	u32 max_open_record_len;
> +	long timeo;
> +	int more = flags & (MSG_SENDPAGE_NOTLAST | MSG_MORE);
> +	int tls_push_record_flags = flags | MSG_SENDPAGE_NOTLAST;
> +	bool done = false;
> +
> +	if (flags &
> +	    ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL | MSG_SENDPAGE_NOTLAST))
> +		return -ENOTSUPP;
> +
> +	if (sk->sk_err)
> +		return -sk->sk_err;
> +
> +	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
> +	rc = tls_complete_pending_work(sk, tls_ctx, flags, &timeo);
> +	if (rc < 0)
> +		return rc;
> +
> +	pfrag = sk_page_frag(sk);
> +
> +	/* KTLS_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 +
> +			      tls_ctx->prepend_size;
> +	do {
> +		if (tls_do_allocation(sk, ctx, pfrag,
> +				      tls_ctx->prepend_size)) {
> +			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 > tls_ctx->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));
> +
> +		if (copy_from_iter_nocache(page_address(pfrag->page) +
> +					       pfrag->offset,
> +					   copy, msg_iter) != copy) {
> +			rc = -EFAULT;
> +			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_push_record(sk,
> +					     tls_ctx,
> +					     ctx,
> +					     record,
> +					     pfrag,
> +					     tls_push_record_flags,
> +					     record_type);
> +			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;
> +	int rc = 0;
> +
> +	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);
> +	return rc;
> +}
> +
> +int tls_device_sendpage(struct sock *sk, struct page *page,
> +			int offset, size_t size, int flags)
> +{
> +	struct iov_iter	msg_iter;
> +	struct kvec iov;
> +	char *kaddr = kmap(page);
> +	int rc = 0;
> +
> +	if (flags & MSG_SENDPAGE_NOTLAST)
> +		flags |= MSG_MORE;
> +
> +	lock_sock(sk);
> +
> +	if (flags & MSG_OOB) {
> +		rc = -ENOTSUPP;
> +		goto out;
> +	}
> +
> +	iov.iov_base = kaddr + offset;
> +	iov.iov_len = size;
> +	iov_iter_kvec(&msg_iter, WRITE | ITER_KVEC, &iov, 1, size);
> +	rc = tls_push_data(sk, &msg_iter, size,
> +			   flags, TLS_RECORD_TYPE_DATA);
> +	kunmap(page);
> +
> +out:
> +	release_sock(sk);
> +	return rc;
> +}
> +
> +struct tls_record_info *tls_get_record(struct tls_offload_context *context,
> +				       u32 seq, u64 *p_record_sn)
> +{
> +	struct tls_record_info *info;
> +	u64 record_sn = context->hint_record_sn;
> +
> +	info = context->retransmit_hint;
> +	if (!info ||
> +	    before(seq, info->end_seq - info->len)) {
> +		/* if retransmit_hint is irrelevant start
> +		 * from the begging of the list
> +		 */
> +		info = list_first_entry(&context->records_list,
> +					struct tls_record_info, list);
> +		record_sn = context->unacked_record_sn;
> +	}
> +
> +	list_for_each_entry_from(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;
> +			return info;
> +		}
> +		record_sn++;
> +	}
> +
> +	return NULL;
> +}
> +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 | ITER_KVEC, NULL, 0, 0);
> +	return tls_push_data(sk, &msg_iter, 0, flags, TLS_RECORD_TYPE_DATA);
> +}
> +
> +int tls_set_device_offload(struct sock *sk, struct tls_context *ctx)
> +{
> +	struct tls_crypto_info *crypto_info;
> +	struct tls_offload_context *offload_ctx;
> +	struct tls_record_info *start_marker_record;
> +	u16 nonece_size, tag_size, iv_size, rec_seq_size;
> +	char *iv, *rec_seq;
> +	int rc;
> +	struct net_device *netdev;
> +	struct sk_buff *skb;
> +
> +	if (!ctx) {
> +		rc = -EINVAL;
> +		goto out;
> +	}
> +
> +	if (ctx->priv_ctx) {
> +		rc = -EEXIST;
> +		goto out;
> +	}
> +
> +	/* We support starting offload on multiple sockets
> +	 * concurrently, So we only need a read lock here.
> +	 */
> +	percpu_down_read(&device_offload_lock);
> +	netdev = get_netdev_for_sock(sk);
> +	if (!netdev) {
> +		pr_err("%s: netdev not found\n", __func__);

_ratelimit?

> +		rc = -EINVAL;
> +		goto release_lock;
> +	}
> +

  Marcelo