/*
 * Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved.
 * Copyright (c) 2016-2017, Dave Watson <davejwatson@fb.com>. All rights reserved.
 * Copyright (c) 2016-2017, Lance Chao <lancerchao@fb.com>. All rights reserved.
 * Copyright (c) 2016, Fridolin Pokorny <fridolin.pokorny@gmail.com>. All rights reserved.
 * Copyright (c) 2016, Nikos Mavrogiannopoulos <nmav@gnutls.org>. All rights reserved.
 * Copyright (c) 2018, Covalent IO, Inc. http://covalent.io
 *
 * 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 <linux/bug.h>
#include <linux/sched/signal.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/splice.h>
#include <crypto/aead.h>

#include <net/strparser.h>
#include <net/tls.h>
#include <trace/events/sock.h>

#include "tls.h"

struct tls_decrypt_arg {
        struct_group(inargs,
        bool zc;
        bool async;
        bool async_done;
        u8 tail;
        );

        struct sk_buff *skb;
};

struct tls_decrypt_ctx {
        struct sock *sk;
        u8 iv[TLS_MAX_IV_SIZE];
        u8 aad[TLS_MAX_AAD_SIZE];
        u8 tail;
        bool free_sgout;
        struct scatterlist sg[];
};

noinline void tls_err_abort(struct sock *sk, int err)
{
        WARN_ON_ONCE(err >= 0);
        /* sk->sk_err should contain a positive error code. */
        WRITE_ONCE(sk->sk_err, -err);
        /* Paired with smp_rmb() in tcp_poll() */
        smp_wmb();
        sk_error_report(sk);
}

static int __skb_nsg(struct sk_buff *skb, int offset, int len,
                     unsigned int recursion_level)
{
        int start = skb_headlen(skb);
        int i, chunk = start - offset;
        struct sk_buff *frag_iter;
        int elt = 0;

        if (unlikely(recursion_level >= 24))
                return -EMSGSIZE;

        if (chunk > 0) {
                if (chunk > len)
                        chunk = len;
                elt++;
                len -= chunk;
                if (len == 0)
                        return elt;
                offset += chunk;
        }

        for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
                int end;

                WARN_ON(start > offset + len);

                end = start + skb_frag_size(&skb_shinfo(skb)->frags[i]);
                chunk = end - offset;
                if (chunk > 0) {
                        if (chunk > len)
                                chunk = len;
                        elt++;
                        len -= chunk;
                        if (len == 0)
                                return elt;
                        offset += chunk;
                }
                start = end;
        }

        if (unlikely(skb_has_frag_list(skb))) {
                skb_walk_frags(skb, frag_iter) {
                        int end, ret;

                        WARN_ON(start > offset + len);

                        end = start + frag_iter->len;
                        chunk = end - offset;
                        if (chunk > 0) {
                                if (chunk > len)
                                        chunk = len;
                                ret = __skb_nsg(frag_iter, offset - start, chunk,
                                                recursion_level + 1);
                                if (unlikely(ret < 0))
                                        return ret;
                                elt += ret;
                                len -= chunk;
                                if (len == 0)
                                        return elt;
                                offset += chunk;
                        }
                        start = end;
                }
        }
        BUG_ON(len);
        return elt;
}

/* Return the number of scatterlist elements required to completely map the
 * skb, or -EMSGSIZE if the recursion depth is exceeded.
 */
static int skb_nsg(struct sk_buff *skb, int offset, int len)
{
        return __skb_nsg(skb, offset, len, 0);
}

static int tls_padding_length(struct tls_prot_info *prot, struct sk_buff *skb,
                              struct tls_decrypt_arg *darg)
{
        struct strp_msg *rxm = strp_msg(skb);
        struct tls_msg *tlm = tls_msg(skb);
        int sub = 0;

        /* Determine zero-padding length */
        if (prot->version == TLS_1_3_VERSION) {
                int offset = rxm->full_len - TLS_TAG_SIZE - 1;
                char content_type = darg->zc ? darg->tail : 0;
                int err;

                while (content_type == 0) {
                        if (offset < prot->prepend_size)
                                return -EBADMSG;
                        err = skb_copy_bits(skb, rxm->offset + offset,
                                            &content_type, 1);
                        if (err)
                                return err;
                        if (content_type)
                                break;
                        sub++;
                        offset--;
                }
                tlm->control = content_type;
        }
        return sub;
}

static void tls_decrypt_done(void *data, int err)
{
        struct aead_request *aead_req = data;
        struct crypto_aead *aead = crypto_aead_reqtfm(aead_req);
        struct scatterlist *sgout = aead_req->dst;
        struct tls_sw_context_rx *ctx;
        struct tls_decrypt_ctx *dctx;
        struct tls_context *tls_ctx;
        struct scatterlist *sg;
        unsigned int pages;
        struct sock *sk;
        int aead_size;

        /* If requests get too backlogged crypto API returns -EBUSY and calls
         * ->complete(-EINPROGRESS) immediately followed by ->complete(0)
         * to make waiting for backlog to flush with crypto_wait_req() easier.
         * First wait converts -EBUSY -> -EINPROGRESS, and the second one
         * -EINPROGRESS -> 0.
         * We have a single struct crypto_async_request per direction, this
         * scheme doesn't help us, so just ignore the first ->complete().
         */
        if (err == -EINPROGRESS)
                return;

        aead_size = sizeof(*aead_req) + crypto_aead_reqsize(aead);
        aead_size = ALIGN(aead_size, __alignof__(*dctx));
        dctx = (void *)((u8 *)aead_req + aead_size);

        sk = dctx->sk;
        tls_ctx = tls_get_ctx(sk);
        ctx = tls_sw_ctx_rx(tls_ctx);

        /* Propagate if there was an err */
        if (err) {
                if (err == -EBADMSG)
                        TLS_INC_STATS(sock_net(sk), LINUX_MIB_TLSDECRYPTERROR);
                ctx->async_wait.err = err;
                tls_err_abort(sk, err);
        }

        /* Free the destination pages if skb was not decrypted inplace */
        if (dctx->free_sgout) {
                /* Skip the first S/G entry as it points to AAD */
                for_each_sg(sg_next(sgout), sg, UINT_MAX, pages) {
                        if (!sg)
                                break;
                        put_page(sg_page(sg));
                }
        }

        kfree(aead_req);

        if (atomic_dec_and_test(&ctx->decrypt_pending))
                complete(&ctx->async_wait.completion);
}

static int tls_decrypt_async_wait(struct tls_sw_context_rx *ctx)
{
        if (!atomic_dec_and_test(&ctx->decrypt_pending))
                crypto_wait_req(-EINPROGRESS, &ctx->async_wait);
        atomic_inc(&ctx->decrypt_pending);

        __skb_queue_purge(&ctx->async_hold);
        return ctx->async_wait.err;
}

static int tls_do_decryption(struct sock *sk,
                             struct scatterlist *sgin,
                             struct scatterlist *sgout,
                             char *iv_recv,
                             size_t data_len,
                             struct aead_request *aead_req,
                             struct tls_decrypt_arg *darg)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_prot_info *prot = &tls_ctx->prot_info;
        struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
        int ret;

        aead_request_set_tfm(aead_req, ctx->aead_recv);
        aead_request_set_ad(aead_req, prot->aad_size);
        aead_request_set_crypt(aead_req, sgin, sgout,
                               data_len + prot->tag_size,
                               (u8 *)iv_recv);

        if (darg->async) {
                aead_request_set_callback(aead_req,
                                          CRYPTO_TFM_REQ_MAY_BACKLOG,
                                          tls_decrypt_done, aead_req);
                DEBUG_NET_WARN_ON_ONCE(atomic_read(&ctx->decrypt_pending) < 1);
                atomic_inc(&ctx->decrypt_pending);
        } else {
                DECLARE_CRYPTO_WAIT(wait);

                aead_request_set_callback(aead_req,
                                          CRYPTO_TFM_REQ_MAY_BACKLOG,
                                          crypto_req_done, &wait);
                ret = crypto_aead_decrypt(aead_req);
                if (ret == -EINPROGRESS || ret == -EBUSY)
                        ret = crypto_wait_req(ret, &wait);
                return ret;
        }

        ret = crypto_aead_decrypt(aead_req);
        if (ret == -EINPROGRESS)
                return 0;

        if (ret == -EBUSY) {
                ret = tls_decrypt_async_wait(ctx);
                darg->async_done = true;
                /* all completions have run, we're not doing async anymore */
                darg->async = false;
                return ret;
        }

        atomic_dec(&ctx->decrypt_pending);
        darg->async = false;

        return ret;
}

static void tls_trim_both_msgs(struct sock *sk, int target_size)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_prot_info *prot = &tls_ctx->prot_info;
        struct tls_sw_context_tx *ctx = tls_sw_ctx_tx(tls_ctx);
        struct tls_rec *rec = ctx->open_rec;

        sk_msg_trim(sk, &rec->msg_plaintext, target_size);
        if (target_size > 0)
                target_size += prot->overhead_size;
        sk_msg_trim(sk, &rec->msg_encrypted, target_size);
}

static int tls_alloc_encrypted_msg(struct sock *sk, int len)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_sw_context_tx *ctx = tls_sw_ctx_tx(tls_ctx);
        struct tls_rec *rec = ctx->open_rec;
        struct sk_msg *msg_en = &rec->msg_encrypted;

        return sk_msg_alloc(sk, msg_en, len, 0);
}

static int tls_clone_plaintext_msg(struct sock *sk, int required)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_prot_info *prot = &tls_ctx->prot_info;
        struct tls_sw_context_tx *ctx = tls_sw_ctx_tx(tls_ctx);
        struct tls_rec *rec = ctx->open_rec;
        struct sk_msg *msg_pl = &rec->msg_plaintext;
        struct sk_msg *msg_en = &rec->msg_encrypted;
        int skip, len;

        /* We add page references worth len bytes from encrypted sg
         * at the end of plaintext sg. It is guaranteed that msg_en
         * has enough required room (ensured by caller).
         */
        len = required - msg_pl->sg.size;

        /* Skip initial bytes in msg_en's data to be able to use
         * same offset of both plain and encrypted data.
         */
        skip = prot->prepend_size + msg_pl->sg.size;

        return sk_msg_clone(sk, msg_pl, msg_en, skip, len);
}

static struct tls_rec *tls_get_rec(struct sock *sk)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_prot_info *prot = &tls_ctx->prot_info;
        struct tls_sw_context_tx *ctx = tls_sw_ctx_tx(tls_ctx);
        struct sk_msg *msg_pl, *msg_en;
        struct tls_rec *rec;
        int mem_size;

        mem_size = sizeof(struct tls_rec) + crypto_aead_reqsize(ctx->aead_send);

        rec = kzalloc(mem_size, sk->sk_allocation);
        if (!rec)
                return NULL;

        msg_pl = &rec->msg_plaintext;
        msg_en = &rec->msg_encrypted;

        sk_msg_init(msg_pl);
        sk_msg_init(msg_en);

        sg_init_table(rec->sg_aead_in, 2);
        sg_set_buf(&rec->sg_aead_in[0], rec->aad_space, prot->aad_size);
        sg_unmark_end(&rec->sg_aead_in[1]);

        sg_init_table(rec->sg_aead_out, 2);
        sg_set_buf(&rec->sg_aead_out[0], rec->aad_space, prot->aad_size);
        sg_unmark_end(&rec->sg_aead_out[1]);

        rec->sk = sk;

        return rec;
}

static void tls_free_rec(struct sock *sk, struct tls_rec *rec)
{
        sk_msg_free(sk, &rec->msg_encrypted);
        sk_msg_free(sk, &rec->msg_plaintext);
        kfree(rec);
}

static void tls_free_open_rec(struct sock *sk)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_sw_context_tx *ctx = tls_sw_ctx_tx(tls_ctx);
        struct tls_rec *rec = ctx->open_rec;

        if (rec) {
                tls_free_rec(sk, rec);
                ctx->open_rec = NULL;
        }
}

int tls_tx_records(struct sock *sk, int flags)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_sw_context_tx *ctx = tls_sw_ctx_tx(tls_ctx);
        struct tls_rec *rec, *tmp;
        struct sk_msg *msg_en;
        int tx_flags, rc = 0;

        if (tls_is_partially_sent_record(tls_ctx)) {
                rec = list_first_entry(&ctx->tx_list,
                                       struct tls_rec, list);

                if (flags == -1)
                        tx_flags = rec->tx_flags;
                else
                        tx_flags = flags;

                rc = tls_push_partial_record(sk, tls_ctx, tx_flags);
                if (rc)
                        goto tx_err;

                /* Full record has been transmitted.
                 * Remove the head of tx_list
                 */
                list_del(&rec->list);
                sk_msg_free(sk, &rec->msg_plaintext);
                kfree(rec);
        }

        /* Tx all ready records */
        list_for_each_entry_safe(rec, tmp, &ctx->tx_list, list) {
                if (READ_ONCE(rec->tx_ready)) {
                        if (flags == -1)
                                tx_flags = rec->tx_flags;
                        else
                                tx_flags = flags;

                        msg_en = &rec->msg_encrypted;
                        rc = tls_push_sg(sk, tls_ctx,
                                         &msg_en->sg.data[msg_en->sg.curr],
                                         0, tx_flags);
                        if (rc)
                                goto tx_err;

                        list_del(&rec->list);
                        sk_msg_free(sk, &rec->msg_plaintext);
                        kfree(rec);
                } else {
                        break;
                }
        }

tx_err:
        if (rc < 0 && rc != -EAGAIN)
                tls_err_abort(sk, rc);

        return rc;
}

static void tls_encrypt_done(void *data, int err)
{
        struct tls_sw_context_tx *ctx;
        struct tls_context *tls_ctx;
        struct tls_prot_info *prot;
        struct tls_rec *rec = data;
        struct scatterlist *sge;
        struct sk_msg *msg_en;
        struct sock *sk;

        if (err == -EINPROGRESS) /* see the comment in tls_decrypt_done() */
                return;

        msg_en = &rec->msg_encrypted;

        sk = rec->sk;
        tls_ctx = tls_get_ctx(sk);
        prot = &tls_ctx->prot_info;
        ctx = tls_sw_ctx_tx(tls_ctx);

        sge = sk_msg_elem(msg_en, msg_en->sg.curr);
        sge->offset -= prot->prepend_size;
        sge->length += prot->prepend_size;

        /* Check if error is previously set on socket */
        if (err || sk->sk_err) {
                rec = NULL;

                /* If err is already set on socket, return the same code */
                if (sk->sk_err) {
                        ctx->async_wait.err = -sk->sk_err;
                } else {
                        ctx->async_wait.err = err;
                        tls_err_abort(sk, err);
                }
        }

        if (rec) {
                struct tls_rec *first_rec;

                /* Mark the record as ready for transmission */
                smp_store_mb(rec->tx_ready, true);

                /* If received record is at head of tx_list, schedule tx */
                first_rec = list_first_entry(&ctx->tx_list,
                                             struct tls_rec, list);
                if (rec == first_rec) {
                        /* Schedule the transmission */
                        if (!test_and_set_bit(BIT_TX_SCHEDULED,
                                              &ctx->tx_bitmask))
                                schedule_delayed_work(&ctx->tx_work.work, 1);
                }
        }

        if (atomic_dec_and_test(&ctx->encrypt_pending))
                complete(&ctx->async_wait.completion);
}

static int tls_encrypt_async_wait(struct tls_sw_context_tx *ctx)
{
        if (!atomic_dec_and_test(&ctx->encrypt_pending))
                crypto_wait_req(-EINPROGRESS, &ctx->async_wait);
        atomic_inc(&ctx->encrypt_pending);

        return ctx->async_wait.err;
}

static int tls_do_encryption(struct sock *sk,
                             struct tls_context *tls_ctx,
                             struct tls_sw_context_tx *ctx,
                             struct aead_request *aead_req,
                             size_t data_len, u32 start)
{
        struct tls_prot_info *prot = &tls_ctx->prot_info;
        struct tls_rec *rec = ctx->open_rec;
        struct sk_msg *msg_en = &rec->msg_encrypted;
        struct scatterlist *sge = sk_msg_elem(msg_en, start);
        int rc, iv_offset = 0;

        /* For CCM based ciphers, first byte of IV is a constant */
        switch (prot->cipher_type) {
        case TLS_CIPHER_AES_CCM_128:
                rec->iv_data[0] = TLS_AES_CCM_IV_B0_BYTE;
                iv_offset = 1;
                break;
        case TLS_CIPHER_SM4_CCM:
                rec->iv_data[0] = TLS_SM4_CCM_IV_B0_BYTE;
                iv_offset = 1;
                break;
        }

        memcpy(&rec->iv_data[iv_offset], tls_ctx->tx.iv,
               prot->iv_size + prot->salt_size);

        tls_xor_iv_with_seq(prot, rec->iv_data + iv_offset,
                            tls_ctx->tx.rec_seq);

        sge->offset += prot->prepend_size;
        sge->length -= prot->prepend_size;

        msg_en->sg.curr = start;

        aead_request_set_tfm(aead_req, ctx->aead_send);
        aead_request_set_ad(aead_req, prot->aad_size);
        aead_request_set_crypt(aead_req, rec->sg_aead_in,
                               rec->sg_aead_out,
                               data_len, rec->iv_data);

        aead_request_set_callback(aead_req, CRYPTO_TFM_REQ_MAY_BACKLOG,
                                  tls_encrypt_done, rec);

        /* Add the record in tx_list */
        list_add_tail((struct list_head *)&rec->list, &ctx->tx_list);
        DEBUG_NET_WARN_ON_ONCE(atomic_read(&ctx->encrypt_pending) < 1);
        atomic_inc(&ctx->encrypt_pending);

        rc = crypto_aead_encrypt(aead_req);
        if (rc == -EBUSY) {
                rc = tls_encrypt_async_wait(ctx);
                rc = rc ?: -EINPROGRESS;
        }
        if (!rc || rc != -EINPROGRESS) {
                atomic_dec(&ctx->encrypt_pending);
                sge->offset -= prot->prepend_size;
                sge->length += prot->prepend_size;
        }

        if (!rc) {
                WRITE_ONCE(rec->tx_ready, true);
        } else if (rc != -EINPROGRESS) {
                list_del(&rec->list);
                return rc;
        }

        /* Unhook the record from context if encryption is not failure */
        ctx->open_rec = NULL;
        tls_advance_record_sn(sk, prot, &tls_ctx->tx);
        return rc;
}

static int tls_split_open_record(struct sock *sk, struct tls_rec *from,
                                 struct tls_rec **to, struct sk_msg *msg_opl,
                                 struct sk_msg *msg_oen, u32 split_point,
                                 u32 tx_overhead_size, u32 *orig_end)
{
        u32 i, j, bytes = 0, apply = msg_opl->apply_bytes;
        struct scatterlist *sge, *osge, *nsge;
        u32 orig_size = msg_opl->sg.size;
        struct scatterlist tmp = { };
        struct sk_msg *msg_npl;
        struct tls_rec *new;
        int ret;

        new = tls_get_rec(sk);
        if (!new)
                return -ENOMEM;
        ret = sk_msg_alloc(sk, &new->msg_encrypted, msg_opl->sg.size +
                           tx_overhead_size, 0);
        if (ret < 0) {
                tls_free_rec(sk, new);
                return ret;
        }

        *orig_end = msg_opl->sg.end;
        i = msg_opl->sg.start;
        sge = sk_msg_elem(msg_opl, i);
        while (apply && sge->length) {
                if (sge->length > apply) {
                        u32 len = sge->length - apply;

                        get_page(sg_page(sge));
                        sg_set_page(&tmp, sg_page(sge), len,
                                    sge->offset + apply);
                        sge->length = apply;
                        bytes += apply;
                        apply = 0;
                } else {
                        apply -= sge->length;
                        bytes += sge->length;
                }

                sk_msg_iter_var_next(i);
                if (i == msg_opl->sg.end)
                        break;
                sge = sk_msg_elem(msg_opl, i);
        }

        msg_opl->sg.end = i;
        msg_opl->sg.curr = i;
        msg_opl->sg.copybreak = 0;
        msg_opl->apply_bytes = 0;
        msg_opl->sg.size = bytes;

        msg_npl = &new->msg_plaintext;
        msg_npl->apply_bytes = apply;
        msg_npl->sg.size = orig_size - bytes;

        j = msg_npl->sg.start;
        nsge = sk_msg_elem(msg_npl, j);
        if (tmp.length) {
                memcpy(nsge, &tmp, sizeof(*nsge));
                sk_msg_iter_var_next(j);
                nsge = sk_msg_elem(msg_npl, j);
        }

        osge = sk_msg_elem(msg_opl, i);
        while (osge->length) {
                memcpy(nsge, osge, sizeof(*nsge));
                sg_unmark_end(nsge);
                sk_msg_iter_var_next(i);
                sk_msg_iter_var_next(j);
                if (i == *orig_end)
                        break;
                osge = sk_msg_elem(msg_opl, i);
                nsge = sk_msg_elem(msg_npl, j);
        }

        msg_npl->sg.end = j;
        msg_npl->sg.curr = j;
        msg_npl->sg.copybreak = 0;

        *to = new;
        return 0;
}

static void tls_merge_open_record(struct sock *sk, struct tls_rec *to,
                                  struct tls_rec *from, u32 orig_end)
{
        struct sk_msg *msg_npl = &from->msg_plaintext;
        struct sk_msg *msg_opl = &to->msg_plaintext;
        struct scatterlist *osge, *nsge;
        u32 i, j;

        i = msg_opl->sg.end;
        sk_msg_iter_var_prev(i);
        j = msg_npl->sg.start;

        osge = sk_msg_elem(msg_opl, i);
        nsge = sk_msg_elem(msg_npl, j);

        if (sg_page(osge) == sg_page(nsge) &&
            osge->offset + osge->length == nsge->offset) {
                osge->length += nsge->length;
                put_page(sg_page(nsge));
        }

        msg_opl->sg.end = orig_end;
        msg_opl->sg.curr = orig_end;
        msg_opl->sg.copybreak = 0;
        msg_opl->apply_bytes = msg_opl->sg.size + msg_npl->sg.size;
        msg_opl->sg.size += msg_npl->sg.size;

        sk_msg_free(sk, &to->msg_encrypted);
        sk_msg_xfer_full(&to->msg_encrypted, &from->msg_encrypted);

        kfree(from);
}

static int tls_push_record(struct sock *sk, 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_sw_context_tx *ctx = tls_sw_ctx_tx(tls_ctx);
        struct tls_rec *rec = ctx->open_rec, *tmp = NULL;
        u32 i, split_point, orig_end;
        struct sk_msg *msg_pl, *msg_en;
        struct aead_request *req;
        bool split;
        int rc;

        if (!rec)
                return 0;

        msg_pl = &rec->msg_plaintext;
        msg_en = &rec->msg_encrypted;

        split_point = msg_pl->apply_bytes;
        split = split_point && split_point < msg_pl->sg.size;
        if (unlikely((!split &&
                      msg_pl->sg.size +
                      prot->overhead_size > msg_en->sg.size) ||
                     (split &&
                      split_point +
                      prot->overhead_size > msg_en->sg.size))) {
                split = true;
                split_point = msg_en->sg.size;
        }
        if (split) {
                rc = tls_split_open_record(sk, rec, &tmp, msg_pl, msg_en,
                                           split_point, prot->overhead_size,
                                           &orig_end);
                if (rc < 0)
                        return rc;
                /* This can happen if above tls_split_open_record allocates
                 * a single large encryption buffer instead of two smaller
                 * ones. In this case adjust pointers and continue without
                 * split.
                 */
                if (!msg_pl->sg.size) {
                        tls_merge_open_record(sk, rec, tmp, orig_end);
                        msg_pl = &rec->msg_plaintext;
                        msg_en = &rec->msg_encrypted;
                        split = false;
                }
                sk_msg_trim(sk, msg_en, msg_pl->sg.size +
                            prot->overhead_size);
        }

        rec->tx_flags = flags;
        req = &rec->aead_req;

        i = msg_pl->sg.end;
        sk_msg_iter_var_prev(i);

        rec->content_type = record_type;
        if (prot->version == TLS_1_3_VERSION) {
                /* Add content type to end of message.  No padding added */
                sg_set_buf(&rec->sg_content_type, &rec->content_type, 1);
                sg_mark_end(&rec->sg_content_type);
                sg_chain(msg_pl->sg.data, msg_pl->sg.end + 1,
                         &rec->sg_content_type);
        } else {
                sg_mark_end(sk_msg_elem(msg_pl, i));
        }

        if (msg_pl->sg.end < msg_pl->sg.start) {
                sg_chain(&msg_pl->sg.data[msg_pl->sg.start],
                         MAX_SKB_FRAGS - msg_pl->sg.start + 1,
                         msg_pl->sg.data);
        }

        i = msg_pl->sg.start;
        sg_chain(rec->sg_aead_in, 2, &msg_pl->sg.data[i]);

        i = msg_en->sg.end;
        sk_msg_iter_var_prev(i);
        sg_mark_end(sk_msg_elem(msg_en, i));

        i = msg_en->sg.start;
        sg_chain(rec->sg_aead_out, 2, &msg_en->sg.data[i]);

        tls_make_aad(rec->aad_space, msg_pl->sg.size + prot->tail_size,
                     tls_ctx->tx.rec_seq, record_type, prot);

        tls_fill_prepend(tls_ctx,
                         page_address(sg_page(&msg_en->sg.data[i])) +
                         msg_en->sg.data[i].offset,
                         msg_pl->sg.size + prot->tail_size,
                         record_type);

        tls_ctx->pending_open_record_frags = false;

        rc = tls_do_encryption(sk, tls_ctx, ctx, req,
                               msg_pl->sg.size + prot->tail_size, i);
        if (rc < 0) {
                if (rc != -EINPROGRESS) {
                        tls_err_abort(sk, -EBADMSG);
                        if (split) {
                                tls_ctx->pending_open_record_frags = true;
                                tls_merge_open_record(sk, rec, tmp, orig_end);
                        }
                }
                ctx->async_capable = 1;
                return rc;
        } else if (split) {
                msg_pl = &tmp->msg_plaintext;
                msg_en = &tmp->msg_encrypted;
                sk_msg_trim(sk, msg_en, msg_pl->sg.size + prot->overhead_size);
                tls_ctx->pending_open_record_frags = true;
                ctx->open_rec = tmp;
        }

        return tls_tx_records(sk, flags);
}

static int bpf_exec_tx_verdict(struct sk_msg *msg, struct sock *sk,
                               bool full_record, u8 record_type,
                               ssize_t *copied, int flags)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_sw_context_tx *ctx = tls_sw_ctx_tx(tls_ctx);
        struct sk_msg msg_redir = { };
        struct sk_psock *psock;
        struct sock *sk_redir;
        struct tls_rec *rec;
        bool enospc, policy, redir_ingress;
        int err = 0, send;
        u32 delta = 0;

        policy = !(flags & MSG_SENDPAGE_NOPOLICY);
        psock = sk_psock_get(sk);
        if (!psock || !policy) {
                err = tls_push_record(sk, flags, record_type);
                if (err && err != -EINPROGRESS && sk->sk_err == EBADMSG) {
                        *copied -= sk_msg_free(sk, msg);
                        tls_free_open_rec(sk);
                        err = -sk->sk_err;
                }
                if (psock)
                        sk_psock_put(sk, psock);
                return err;
        }
more_data:
        enospc = sk_msg_full(msg);
        if (psock->eval == __SK_NONE) {
                delta = msg->sg.size;
                psock->eval = sk_psock_msg_verdict(sk, psock, msg);
                delta -= msg->sg.size;

                if ((s32)delta > 0) {
                        /* It indicates that we executed bpf_msg_pop_data(),
                         * causing the plaintext data size to decrease.
                         * Therefore the encrypted data size also needs to
                         * correspondingly decrease. We only need to subtract
                         * delta to calculate the new ciphertext length since
                         * ktls does not support block encryption.
                         */
                        struct sk_msg *enc = &ctx->open_rec->msg_encrypted;

                        sk_msg_trim(sk, enc, enc->sg.size - delta);
                }
        }
        if (msg->cork_bytes && msg->cork_bytes > msg->sg.size &&
            !enospc && !full_record) {
                err = -ENOSPC;
                goto out_err;
        }
        msg->cork_bytes = 0;
        send = msg->sg.size;
        if (msg->apply_bytes && msg->apply_bytes < send)
                send = msg->apply_bytes;

        switch (psock->eval) {
        case __SK_PASS:
                err = tls_push_record(sk, flags, record_type);
                if (err && err != -EINPROGRESS && sk->sk_err == EBADMSG) {
                        *copied -= sk_msg_free(sk, msg);
                        tls_free_open_rec(sk);
                        err = -sk->sk_err;
                        goto out_err;
                }
                break;
        case __SK_REDIRECT:
                redir_ingress = psock->redir_ingress;
                sk_redir = psock->sk_redir;
                memcpy(&msg_redir, msg, sizeof(*msg));
                if (msg->apply_bytes < send)
                        msg->apply_bytes = 0;
                else
                        msg->apply_bytes -= send;
                sk_msg_return_zero(sk, msg, send);
                msg->sg.size -= send;
                release_sock(sk);
                err = tcp_bpf_sendmsg_redir(sk_redir, redir_ingress,
                                            &msg_redir, send, flags);
                lock_sock(sk);
                if (err < 0) {
                        /* Regardless of whether the data represented by
                         * msg_redir is sent successfully, we have already
                         * uncharged it via sk_msg_return_zero(). The
                         * msg->sg.size represents the remaining unprocessed
                         * data, which needs to be uncharged here.
                         */
                        sk_mem_uncharge(sk, msg->sg.size);
                        *copied -= sk_msg_free_nocharge(sk, &msg_redir);
                        msg->sg.size = 0;
                }
                if (msg->sg.size == 0)
                        tls_free_open_rec(sk);
                break;
        case __SK_DROP:
        default:
                sk_msg_free_partial(sk, msg, send);
                if (msg->apply_bytes < send)
                        msg->apply_bytes = 0;
                else
                        msg->apply_bytes -= send;
                if (msg->sg.size == 0)
                        tls_free_open_rec(sk);
                *copied -= (send + delta);
                err = -EACCES;
        }

        if (likely(!err)) {
                bool reset_eval = !ctx->open_rec;

                rec = ctx->open_rec;
                if (rec) {
                        msg = &rec->msg_plaintext;
                        if (!msg->apply_bytes)
                                reset_eval = true;
                }
                if (reset_eval) {
                        psock->eval = __SK_NONE;
                        if (psock->sk_redir) {
                                sock_put(psock->sk_redir);
                                psock->sk_redir = NULL;
                        }
                }
                if (rec)
                        goto more_data;
        }
 out_err:
        sk_psock_put(sk, psock);
        return err;
}

static int tls_sw_push_pending_record(struct sock *sk, int flags)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_sw_context_tx *ctx = tls_sw_ctx_tx(tls_ctx);
        struct tls_rec *rec = ctx->open_rec;
        struct sk_msg *msg_pl;
        size_t copied;

        if (!rec)
                return 0;

        msg_pl = &rec->msg_plaintext;
        copied = msg_pl->sg.size;
        if (!copied)
                return 0;

        return bpf_exec_tx_verdict(msg_pl, sk, true, TLS_RECORD_TYPE_DATA,
                                   &copied, flags);
}

static int tls_sw_sendmsg_splice(struct sock *sk, struct msghdr *msg,
                                 struct sk_msg *msg_pl, size_t try_to_copy,
                                 ssize_t *copied)
{
        struct page *page = NULL, **pages = &page;

        do {
                ssize_t part;
                size_t off;

                part = iov_iter_extract_pages(&msg->msg_iter, &pages,
                                              try_to_copy, 1, 0, &off);
                if (part <= 0)
                        return part ?: -EIO;

                if (WARN_ON_ONCE(!sendpage_ok(page))) {
                        iov_iter_revert(&msg->msg_iter, part);
                        return -EIO;
                }

                sk_msg_page_add(msg_pl, page, part, off);
                msg_pl->sg.copybreak = 0;
                msg_pl->sg.curr = msg_pl->sg.end;
                sk_mem_charge(sk, part);
                *copied += part;
                try_to_copy -= part;
        } while (try_to_copy && !sk_msg_full(msg_pl));

        return 0;
}

static int tls_sw_sendmsg_locked(struct sock *sk, struct msghdr *msg,
                                 size_t size)
{
        long timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_prot_info *prot = &tls_ctx->prot_info;
        struct tls_sw_context_tx *ctx = tls_sw_ctx_tx(tls_ctx);
        bool async_capable = ctx->async_capable;
        unsigned char record_type = TLS_RECORD_TYPE_DATA;
        bool is_kvec = iov_iter_is_kvec(&msg->msg_iter);
        bool eor = !(msg->msg_flags & MSG_MORE);
        size_t try_to_copy;
        ssize_t copied = 0;
        struct sk_msg *msg_pl, *msg_en;
        struct tls_rec *rec;
        int required_size;
        int num_async = 0;
        bool full_record;
        int record_room;
        int num_zc = 0;
        int orig_size;
        int ret = 0;

        if (!eor && (msg->msg_flags & MSG_EOR))
                return -EINVAL;

        if (unlikely(msg->msg_controllen)) {
                ret = tls_process_cmsg(sk, msg, &record_type);
                if (ret) {
                        if (ret == -EINPROGRESS)
                                num_async++;
                        else if (ret != -EAGAIN)
                                goto end;
                }
        }

        while (msg_data_left(msg)) {
                if (sk->sk_err) {
                        ret = -sk->sk_err;
                        goto send_end;
                }

                if (ctx->open_rec)
                        rec = ctx->open_rec;
                else
                        rec = ctx->open_rec = tls_get_rec(sk);
                if (!rec) {
                        ret = -ENOMEM;
                        goto send_end;
                }

                msg_pl = &rec->msg_plaintext;
                msg_en = &rec->msg_encrypted;

                orig_size = msg_pl->sg.size;
                full_record = false;
                try_to_copy = msg_data_left(msg);
                record_room = tls_ctx->tx_max_payload_len - msg_pl->sg.size;
                if (try_to_copy >= record_room) {
                        try_to_copy = record_room;
                        full_record = true;
                }

                required_size = msg_pl->sg.size + try_to_copy +
                                prot->overhead_size;

                if (!sk_stream_memory_free(sk))
                        goto wait_for_sndbuf;

alloc_encrypted:
                ret = tls_alloc_encrypted_msg(sk, required_size);
                if (ret) {
                        if (ret != -ENOSPC)
                                goto wait_for_memory;

                        /* Adjust try_to_copy according to the amount that was
                         * actually allocated. The difference is due
                         * to max sg elements limit
                         */
                        try_to_copy -= required_size - msg_en->sg.size;
                        full_record = true;
                }

                if (try_to_copy && (msg->msg_flags & MSG_SPLICE_PAGES)) {
                        ret = tls_sw_sendmsg_splice(sk, msg, msg_pl,
                                                    try_to_copy, &copied);
                        if (ret < 0)
                                goto send_end;
                        tls_ctx->pending_open_record_frags = true;

                        if (sk_msg_full(msg_pl)) {
                                full_record = true;
                                sk_msg_trim(sk, msg_en,
                                            msg_pl->sg.size + prot->overhead_size);
                        }

                        if (full_record || eor)
                                goto copied;
                        continue;
                }

                if (!is_kvec && (full_record || eor) && !async_capable) {
                        u32 first = msg_pl->sg.end;

                        ret = sk_msg_zerocopy_from_iter(sk, &msg->msg_iter,
                                                        msg_pl, try_to_copy);
                        if (ret)
                                goto fallback_to_reg_send;

                        num_zc++;
                        copied += try_to_copy;

                        sk_msg_sg_copy_set(msg_pl, first);
                        ret = bpf_exec_tx_verdict(msg_pl, sk, full_record,
                                                  record_type, &copied,
                                                  msg->msg_flags);
                        if (ret) {
                                if (ret == -EINPROGRESS)
                                        num_async++;
                                else if (ret == -ENOMEM)
                                        goto wait_for_memory;
                                else if (ctx->open_rec && ret == -ENOSPC) {
                                        if (msg_pl->cork_bytes) {
                                                ret = 0;
                                                goto send_end;
                                        }
                                        goto rollback_iter;
                                } else if (ret != -EAGAIN)
                                        goto send_end;
                        }

                        /* Transmit if any encryptions have completed */
                        if (test_and_clear_bit(BIT_TX_SCHEDULED, &ctx->tx_bitmask)) {
                                cancel_delayed_work(&ctx->tx_work.work);
                                tls_tx_records(sk, msg->msg_flags);
                        }

                        continue;
rollback_iter:
                        copied -= try_to_copy;
                        sk_msg_sg_copy_clear(msg_pl, first);
                        iov_iter_revert(&msg->msg_iter,
                                        msg_pl->sg.size - orig_size);
fallback_to_reg_send:
                        sk_msg_trim(sk, msg_pl, orig_size);
                }

                required_size = msg_pl->sg.size + try_to_copy;

                ret = tls_clone_plaintext_msg(sk, required_size);
                if (ret) {
                        if (ret != -ENOSPC)
                                goto send_end;

                        /* Adjust try_to_copy according to the amount that was
                         * actually allocated. The difference is due
                         * to max sg elements limit
                         */
                        try_to_copy -= required_size - msg_pl->sg.size;
                        full_record = true;
                        sk_msg_trim(sk, msg_en,
                                    msg_pl->sg.size + prot->overhead_size);
                }

                if (try_to_copy) {
                        ret = sk_msg_memcopy_from_iter(sk, &msg->msg_iter,
                                                       msg_pl, try_to_copy);
                        if (ret < 0)
                                goto trim_sgl;
                }

                /* Open records defined only if successfully copied, otherwise
                 * we would trim the sg but not reset the open record frags.
                 */
                tls_ctx->pending_open_record_frags = true;
                copied += try_to_copy;
copied:
                if (full_record || eor) {
                        ret = bpf_exec_tx_verdict(msg_pl, sk, full_record,
                                                  record_type, &copied,
                                                  msg->msg_flags);
                        if (ret) {
                                if (ret == -EINPROGRESS)
                                        num_async++;
                                else if (ret == -ENOMEM)
                                        goto wait_for_memory;
                                else if (ret != -EAGAIN) {
                                        if (ret == -ENOSPC)
                                                ret = 0;
                                        goto send_end;
                                }
                        }

                        /* Transmit if any encryptions have completed */
                        if (test_and_clear_bit(BIT_TX_SCHEDULED, &ctx->tx_bitmask)) {
                                cancel_delayed_work(&ctx->tx_work.work);
                                tls_tx_records(sk, msg->msg_flags);
                        }
                }

                continue;

wait_for_sndbuf:
                set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
                ret = sk_stream_wait_memory(sk, &timeo);
                if (ret) {
trim_sgl:
                        if (ctx->open_rec)
                                tls_trim_both_msgs(sk, orig_size);
                        goto send_end;
                }

                if (ctx->open_rec && msg_en->sg.size < required_size)
                        goto alloc_encrypted;
        }

send_end:
        if (!num_async) {
                goto end;
        } else if (num_zc || eor) {
                int err;

                /* Wait for pending encryptions to get completed */
                err = tls_encrypt_async_wait(ctx);
                if (err) {
                        ret = err;
                        copied = 0;
                }
        }

        /* Transmit if any encryptions have completed */
        if (test_and_clear_bit(BIT_TX_SCHEDULED, &ctx->tx_bitmask)) {
                cancel_delayed_work(&ctx->tx_work.work);
                tls_tx_records(sk, msg->msg_flags);
        }

end:
        ret = sk_stream_error(sk, msg->msg_flags, ret);
        return copied > 0 ? copied : ret;
}

int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        int ret;

        if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL |
                               MSG_CMSG_COMPAT | MSG_SPLICE_PAGES | MSG_EOR |
                               MSG_SENDPAGE_NOPOLICY))
                return -EOPNOTSUPP;

        ret = mutex_lock_interruptible(&tls_ctx->tx_lock);
        if (ret)
                return ret;
        lock_sock(sk);
        ret = tls_sw_sendmsg_locked(sk, msg, size);
        release_sock(sk);
        mutex_unlock(&tls_ctx->tx_lock);
        return ret;
}

/*
 * Handle unexpected EOF during splice without SPLICE_F_MORE set.
 */
void tls_sw_splice_eof(struct socket *sock)
{
        struct sock *sk = sock->sk;
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_sw_context_tx *ctx = tls_sw_ctx_tx(tls_ctx);
        struct tls_rec *rec;
        struct sk_msg *msg_pl;
        ssize_t copied = 0;
        bool retrying = false;
        int ret = 0;

        if (!ctx->open_rec)
                return;

        mutex_lock(&tls_ctx->tx_lock);
        lock_sock(sk);

retry:
        /* same checks as in tls_sw_push_pending_record() */
        rec = ctx->open_rec;
        if (!rec)
                goto unlock;

        msg_pl = &rec->msg_plaintext;
        if (msg_pl->sg.size == 0)
                goto unlock;

        /* Check the BPF advisor and perform transmission. */
        ret = bpf_exec_tx_verdict(msg_pl, sk, false, TLS_RECORD_TYPE_DATA,
                                  &copied, 0);
        switch (ret) {
        case 0:
        case -EAGAIN:
                if (retrying)
                        goto unlock;
                retrying = true;
                goto retry;
        case -EINPROGRESS:
                break;
        default:
                goto unlock;
        }

        /* Wait for pending encryptions to get completed */
        if (tls_encrypt_async_wait(ctx))
                goto unlock;

        /* Transmit if any encryptions have completed */
        if (test_and_clear_bit(BIT_TX_SCHEDULED, &ctx->tx_bitmask)) {
                cancel_delayed_work(&ctx->tx_work.work);
                tls_tx_records(sk, 0);
        }

unlock:
        release_sock(sk);
        mutex_unlock(&tls_ctx->tx_lock);
}

static int
tls_rx_rec_wait(struct sock *sk, struct sk_psock *psock, bool nonblock,
                bool released)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
        DEFINE_WAIT_FUNC(wait, woken_wake_function);
        int ret = 0;
        long timeo;

        /* a rekey is pending, let userspace deal with it */
        if (unlikely(ctx->key_update_pending))
                return -EKEYEXPIRED;

        timeo = sock_rcvtimeo(sk, nonblock);

        while (!tls_strp_msg_ready(ctx)) {
                if (!sk_psock_queue_empty(psock))
                        return 0;

                if (sk->sk_err)
                        return sock_error(sk);

                if (ret < 0)
                        return ret;

                if (!skb_queue_empty(&sk->sk_receive_queue)) {
                        tls_strp_check_rcv(&ctx->strp);
                        if (tls_strp_msg_ready(ctx))
                                break;
                }

                if (sk->sk_shutdown & RCV_SHUTDOWN)
                        return 0;

                if (sock_flag(sk, SOCK_DONE))
                        return 0;

                if (!timeo)
                        return -EAGAIN;

                released = true;
                add_wait_queue(sk_sleep(sk), &wait);
                sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
                ret = sk_wait_event(sk, &timeo,
                                    tls_strp_msg_ready(ctx) ||
                                    !sk_psock_queue_empty(psock),
                                    &wait);
                sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
                remove_wait_queue(sk_sleep(sk), &wait);

                /* Handle signals */
                if (signal_pending(current))
                        return sock_intr_errno(timeo);
        }

        if (unlikely(!tls_strp_msg_load(&ctx->strp, released)))
                return tls_rx_rec_wait(sk, psock, nonblock, false);

        return 1;
}

static int tls_setup_from_iter(struct iov_iter *from,
                               int length, int *pages_used,
                               struct scatterlist *to,
                               int to_max_pages)
{
        int rc = 0, i = 0, num_elem = *pages_used, maxpages;
        struct page *pages[MAX_SKB_FRAGS];
        unsigned int size = 0;
        ssize_t copied, use;
        size_t offset;

        while (length > 0) {
                i = 0;
                maxpages = to_max_pages - num_elem;
                if (maxpages == 0) {
                        rc = -EFAULT;
                        goto out;
                }
                copied = iov_iter_get_pages2(from, pages,
                                            length,
                                            maxpages, &offset);
                if (copied <= 0) {
                        rc = -EFAULT;
                        goto out;
                }

                length -= copied;
                size += copied;
                while (copied) {
                        use = min_t(int, copied, PAGE_SIZE - offset);

                        sg_set_page(&to[num_elem],
                                    pages[i], use, offset);
                        sg_unmark_end(&to[num_elem]);
                        /* We do not uncharge memory from this API */

                        offset = 0;
                        copied -= use;

                        i++;
                        num_elem++;
                }
        }
        /* Mark the end in the last sg entry if newly added */
        if (num_elem > *pages_used)
                sg_mark_end(&to[num_elem - 1]);
out:
        if (rc)
                iov_iter_revert(from, size);
        *pages_used = num_elem;

        return rc;
}

static struct sk_buff *
tls_alloc_clrtxt_skb(struct sock *sk, struct sk_buff *skb,
                     unsigned int full_len)
{
        struct strp_msg *clr_rxm;
        struct sk_buff *clr_skb;
        int err;

        clr_skb = alloc_skb_with_frags(0, full_len, TLS_PAGE_ORDER,
                                       &err, sk->sk_allocation);
        if (!clr_skb)
                return NULL;

        skb_copy_header(clr_skb, skb);
        clr_skb->len = full_len;
        clr_skb->data_len = full_len;

        clr_rxm = strp_msg(clr_skb);
        clr_rxm->offset = 0;

        return clr_skb;
}

/* Decrypt handlers
 *
 * tls_decrypt_sw() and tls_decrypt_device() are decrypt handlers.
 * They must transform the darg in/out argument are as follows:
 *       |          Input            |         Output
 * -------------------------------------------------------------------
 *    zc | Zero-copy decrypt allowed | Zero-copy performed
 * async | Async decrypt allowed     | Async crypto used / in progress
 *   skb |            *              | Output skb
 *
 * If ZC decryption was performed darg.skb will point to the input skb.
 */

/* This function decrypts the input skb into either out_iov or in out_sg
 * or in skb buffers itself. The input parameter 'darg->zc' indicates if
 * zero-copy mode needs to be tried or not. With zero-copy mode, either
 * out_iov or out_sg must be non-NULL. In case both out_iov and out_sg are
 * NULL, then the decryption happens inside skb buffers itself, i.e.
 * zero-copy gets disabled and 'darg->zc' is updated.
 */
static int tls_decrypt_sg(struct sock *sk, struct iov_iter *out_iov,
                          struct scatterlist *out_sg,
                          struct tls_decrypt_arg *darg)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
        struct tls_prot_info *prot = &tls_ctx->prot_info;
        int n_sgin, n_sgout, aead_size, err, pages = 0;
        struct sk_buff *skb = tls_strp_msg(ctx);
        const struct strp_msg *rxm = strp_msg(skb);
        const struct tls_msg *tlm = tls_msg(skb);
        struct aead_request *aead_req;
        struct scatterlist *sgin = NULL;
        struct scatterlist *sgout = NULL;
        const int data_len = rxm->full_len - prot->overhead_size;
        int tail_pages = !!prot->tail_size;
        struct tls_decrypt_ctx *dctx;
        struct sk_buff *clear_skb;
        int iv_offset = 0;
        u8 *mem;

        n_sgin = skb_nsg(skb, rxm->offset + prot->prepend_size,
                         rxm->full_len - prot->prepend_size);
        if (n_sgin < 1)
                return n_sgin ?: -EBADMSG;

        if (darg->zc && (out_iov || out_sg)) {
                clear_skb = NULL;

                if (out_iov)
                        n_sgout = 1 + tail_pages +
                                iov_iter_npages_cap(out_iov, INT_MAX, data_len);
                else
                        n_sgout = sg_nents(out_sg);
        } else {
                darg->zc = false;

                clear_skb = tls_alloc_clrtxt_skb(sk, skb, rxm->full_len);
                if (!clear_skb)
                        return -ENOMEM;

                n_sgout = 1 + skb_shinfo(clear_skb)->nr_frags;
        }

        /* Increment to accommodate AAD */
        n_sgin = n_sgin + 1;

        /* Allocate a single block of memory which contains
         *   aead_req || tls_decrypt_ctx.
         * Both structs are variable length.
         */
        aead_size = sizeof(*aead_req) + crypto_aead_reqsize(ctx->aead_recv);
        aead_size = ALIGN(aead_size, __alignof__(*dctx));
        mem = kmalloc(aead_size + struct_size(dctx, sg, size_add(n_sgin, n_sgout)),
                      sk->sk_allocation);
        if (!mem) {
                err = -ENOMEM;
                goto exit_free_skb;
        }

        /* Segment the allocated memory */
        aead_req = (struct aead_request *)mem;
        dctx = (struct tls_decrypt_ctx *)(mem + aead_size);
        dctx->sk = sk;
        sgin = &dctx->sg[0];
        sgout = &dctx->sg[n_sgin];

        /* For CCM based ciphers, first byte of nonce+iv is a constant */
        switch (prot->cipher_type) {
        case TLS_CIPHER_AES_CCM_128:
                dctx->iv[0] = TLS_AES_CCM_IV_B0_BYTE;
                iv_offset = 1;
                break;
        case TLS_CIPHER_SM4_CCM:
                dctx->iv[0] = TLS_SM4_CCM_IV_B0_BYTE;
                iv_offset = 1;
                break;
        }

        /* Prepare IV */
        if (prot->version == TLS_1_3_VERSION ||
            prot->cipher_type == TLS_CIPHER_CHACHA20_POLY1305) {
                memcpy(&dctx->iv[iv_offset], tls_ctx->rx.iv,
                       prot->iv_size + prot->salt_size);
        } else {
                err = skb_copy_bits(skb, rxm->offset + TLS_HEADER_SIZE,
                                    &dctx->iv[iv_offset] + prot->salt_size,
                                    prot->iv_size);
                if (err < 0)
                        goto exit_free;
                memcpy(&dctx->iv[iv_offset], tls_ctx->rx.iv, prot->salt_size);
        }
        tls_xor_iv_with_seq(prot, &dctx->iv[iv_offset], tls_ctx->rx.rec_seq);

        /* Prepare AAD */
        tls_make_aad(dctx->aad, rxm->full_len - prot->overhead_size +
                     prot->tail_size,
                     tls_ctx->rx.rec_seq, tlm->control, prot);

        /* Prepare sgin */
        sg_init_table(sgin, n_sgin);
        sg_set_buf(&sgin[0], dctx->aad, prot->aad_size);
        err = skb_to_sgvec(skb, &sgin[1],
                           rxm->offset + prot->prepend_size,
                           rxm->full_len - prot->prepend_size);
        if (err < 0)
                goto exit_free;

        if (clear_skb) {
                sg_init_table(sgout, n_sgout);
                sg_set_buf(&sgout[0], dctx->aad, prot->aad_size);

                err = skb_to_sgvec(clear_skb, &sgout[1], prot->prepend_size,
                                   data_len + prot->tail_size);
                if (err < 0)
                        goto exit_free;
        } else if (out_iov) {
                sg_init_table(sgout, n_sgout);
                sg_set_buf(&sgout[0], dctx->aad, prot->aad_size);

                err = tls_setup_from_iter(out_iov, data_len, &pages, &sgout[1],
                                          (n_sgout - 1 - tail_pages));
                if (err < 0)
                        goto exit_free_pages;

                if (prot->tail_size) {
                        sg_unmark_end(&sgout[pages]);
                        sg_set_buf(&sgout[pages + 1], &dctx->tail,
                                   prot->tail_size);
                        sg_mark_end(&sgout[pages + 1]);
                }
        } else if (out_sg) {
                memcpy(sgout, out_sg, n_sgout * sizeof(*sgout));
        }
        dctx->free_sgout = !!pages;

        /* Prepare and submit AEAD request */
        err = tls_do_decryption(sk, sgin, sgout, dctx->iv,
                                data_len + prot->tail_size, aead_req, darg);
        if (err) {
                if (darg->async_done)
                        goto exit_free_skb;
                goto exit_free_pages;
        }

        darg->skb = clear_skb ?: tls_strp_msg(ctx);
        clear_skb = NULL;

        if (unlikely(darg->async)) {
                err = tls_strp_msg_hold(&ctx->strp, &ctx->async_hold);
                if (err) {
                        err = tls_decrypt_async_wait(ctx);
                        darg->async = false;
                }
                return err;
        }

        if (unlikely(darg->async_done))
                return 0;

        if (prot->tail_size)
                darg->tail = dctx->tail;

exit_free_pages:
        /* Release the pages in case iov was mapped to pages */
        for (; pages > 0; pages--)
                put_page(sg_page(&sgout[pages]));
exit_free:
        kfree(mem);
exit_free_skb:
        consume_skb(clear_skb);
        return err;
}

static int
tls_decrypt_sw(struct sock *sk, struct tls_context *tls_ctx,
               struct msghdr *msg, struct tls_decrypt_arg *darg)
{
        struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
        struct tls_prot_info *prot = &tls_ctx->prot_info;
        struct strp_msg *rxm;
        int pad, err;

        err = tls_decrypt_sg(sk, &msg->msg_iter, NULL, darg);
        if (err < 0) {
                if (err == -EBADMSG)
                        TLS_INC_STATS(sock_net(sk), LINUX_MIB_TLSDECRYPTERROR);
                return err;
        }
        /* keep going even for ->async, the code below is TLS 1.3 */

        /* If opportunistic TLS 1.3 ZC failed retry without ZC */
        if (unlikely(darg->zc && prot->version == TLS_1_3_VERSION &&
                     darg->tail != TLS_RECORD_TYPE_DATA)) {
                darg->zc = false;
                if (!darg->tail)
                        TLS_INC_STATS(sock_net(sk), LINUX_MIB_TLSRXNOPADVIOL);
                TLS_INC_STATS(sock_net(sk), LINUX_MIB_TLSDECRYPTRETRY);
                return tls_decrypt_sw(sk, tls_ctx, msg, darg);
        }

        pad = tls_padding_length(prot, darg->skb, darg);
        if (pad < 0) {
                if (darg->skb != tls_strp_msg(ctx))
                        consume_skb(darg->skb);
                return pad;
        }

        rxm = strp_msg(darg->skb);
        rxm->full_len -= pad;

        return 0;
}

static int
tls_decrypt_device(struct sock *sk, struct msghdr *msg,
                   struct tls_context *tls_ctx, struct tls_decrypt_arg *darg)
{
        struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
        struct tls_prot_info *prot = &tls_ctx->prot_info;
        struct strp_msg *rxm;
        int pad, err;

        if (tls_ctx->rx_conf != TLS_HW)
                return 0;

        err = tls_device_decrypted(sk, tls_ctx);
        if (err <= 0)
                return err;

        pad = tls_padding_length(prot, tls_strp_msg(ctx), darg);
        if (pad < 0)
                return pad;

        darg->async = false;
        darg->skb = tls_strp_msg(ctx);
        /* ->zc downgrade check, in case TLS 1.3 gets here */
        darg->zc &= !(prot->version == TLS_1_3_VERSION &&
                      tls_msg(darg->skb)->control != TLS_RECORD_TYPE_DATA);

        rxm = strp_msg(darg->skb);
        rxm->full_len -= pad;

        if (!darg->zc) {
                /* Non-ZC case needs a real skb */
                darg->skb = tls_strp_msg_detach(ctx);
                if (!darg->skb)
                        return -ENOMEM;
        } else {
                unsigned int off, len;

                /* In ZC case nobody cares about the output skb.
                 * Just copy the data here. Note the skb is not fully trimmed.
                 */
                off = rxm->offset + prot->prepend_size;
                len = rxm->full_len - prot->overhead_size;

                err = skb_copy_datagram_msg(darg->skb, off, msg, len);
                if (err)
                        return err;
        }
        return 1;
}

static int tls_check_pending_rekey(struct sock *sk, struct tls_context *ctx,
                                   struct sk_buff *skb)
{
        const struct strp_msg *rxm = strp_msg(skb);
        const struct tls_msg *tlm = tls_msg(skb);
        char hs_type;
        int err;

        if (likely(tlm->control != TLS_RECORD_TYPE_HANDSHAKE))
                return 0;

        if (rxm->full_len < 1)
                return 0;

        err = skb_copy_bits(skb, rxm->offset, &hs_type, 1);
        if (err < 0) {
                DEBUG_NET_WARN_ON_ONCE(1);
                return err;
        }

        if (hs_type == TLS_HANDSHAKE_KEYUPDATE) {
                struct tls_sw_context_rx *rx_ctx = ctx->priv_ctx_rx;

                WRITE_ONCE(rx_ctx->key_update_pending, true);
                TLS_INC_STATS(sock_net(sk), LINUX_MIB_TLSRXREKEYRECEIVED);
        }

        return 0;
}

static int tls_rx_one_record(struct sock *sk, struct msghdr *msg,
                             struct tls_decrypt_arg *darg)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_prot_info *prot = &tls_ctx->prot_info;
        struct strp_msg *rxm;
        int err;

        err = tls_decrypt_device(sk, msg, tls_ctx, darg);
        if (!err)
                err = tls_decrypt_sw(sk, tls_ctx, msg, darg);
        if (err < 0)
                return err;

        rxm = strp_msg(darg->skb);
        rxm->offset += prot->prepend_size;
        rxm->full_len -= prot->overhead_size;
        tls_advance_record_sn(sk, prot, &tls_ctx->rx);

        return tls_check_pending_rekey(sk, tls_ctx, darg->skb);
}

int decrypt_skb(struct sock *sk, struct scatterlist *sgout)
{
        struct tls_decrypt_arg darg = { .zc = true, };

        return tls_decrypt_sg(sk, NULL, sgout, &darg);
}

/* All records returned from a recvmsg() call must have the same type.
 * 0 is not a valid content type. Use it as "no type reported, yet".
 */
static int tls_record_content_type(struct msghdr *msg, struct tls_msg *tlm,
                                   u8 *control)
{
        int err;

        if (!*control) {
                *control = tlm->control;
                if (!*control)
                        return -EBADMSG;

                err = put_cmsg(msg, SOL_TLS, TLS_GET_RECORD_TYPE,
                               sizeof(*control), control);
                if (*control != TLS_RECORD_TYPE_DATA) {
                        if (err || msg->msg_flags & MSG_CTRUNC)
                                return -EIO;
                }
        } else if (*control != tlm->control) {
                return 0;
        }

        return 1;
}

static void tls_rx_rec_done(struct tls_sw_context_rx *ctx)
{
        tls_strp_msg_done(&ctx->strp);
}

/* This function traverses the rx_list in tls receive context to copies the
 * decrypted records into the buffer provided by caller zero copy is not
 * true. Further, the records are removed from the rx_list if it is not a peek
 * case and the record has been consumed completely.
 */
static int process_rx_list(struct tls_sw_context_rx *ctx,
                           struct msghdr *msg,
                           u8 *control,
                           size_t skip,
                           size_t len,
                           bool is_peek,
                           bool *more)
{
        struct sk_buff *skb = skb_peek(&ctx->rx_list);
        struct tls_msg *tlm;
        ssize_t copied = 0;
        int err;

        while (skip && skb) {
                struct strp_msg *rxm = strp_msg(skb);
                tlm = tls_msg(skb);

                err = tls_record_content_type(msg, tlm, control);
                if (err <= 0)
                        goto more;

                if (skip < rxm->full_len)
                        break;

                skip = skip - rxm->full_len;
                skb = skb_peek_next(skb, &ctx->rx_list);
        }

        while (len && skb) {
                struct sk_buff *next_skb;
                struct strp_msg *rxm = strp_msg(skb);
                int chunk = min_t(unsigned int, rxm->full_len - skip, len);

                tlm = tls_msg(skb);

                err = tls_record_content_type(msg, tlm, control);
                if (err <= 0)
                        goto more;

                err = skb_copy_datagram_msg(skb, rxm->offset + skip,
                                            msg, chunk);
                if (err < 0)
                        goto more;

                len = len - chunk;
                copied = copied + chunk;

                /* Consume the data from record if it is non-peek case*/
                if (!is_peek) {
                        rxm->offset = rxm->offset + chunk;
                        rxm->full_len = rxm->full_len - chunk;

                        /* Return if there is unconsumed data in the record */
                        if (rxm->full_len - skip)
                                break;
                }

                /* The remaining skip-bytes must lie in 1st record in rx_list.
                 * So from the 2nd record, 'skip' should be 0.
                 */
                skip = 0;

                if (msg)
                        msg->msg_flags |= MSG_EOR;

                next_skb = skb_peek_next(skb, &ctx->rx_list);

                if (!is_peek) {
                        __skb_unlink(skb, &ctx->rx_list);
                        consume_skb(skb);
                }

                skb = next_skb;
        }
        err = 0;

out:
        return copied ? : err;
more:
        if (more)
                *more = true;
        goto out;
}

static bool
tls_read_flush_backlog(struct sock *sk, struct tls_prot_info *prot,
                       size_t len_left, size_t decrypted, ssize_t done,
                       size_t *flushed_at)
{
        size_t max_rec;

        if (len_left <= decrypted)
                return false;

        max_rec = prot->overhead_size - prot->tail_size + TLS_MAX_PAYLOAD_SIZE;
        if (done - *flushed_at < SZ_128K && tcp_inq(sk) > max_rec)
                return false;

        *flushed_at = done;
        return sk_flush_backlog(sk);
}

static int tls_rx_reader_acquire(struct sock *sk, struct tls_sw_context_rx *ctx,
                                 bool nonblock)
{
        long timeo;
        int ret;

        timeo = sock_rcvtimeo(sk, nonblock);

        while (unlikely(ctx->reader_present)) {
                DEFINE_WAIT_FUNC(wait, woken_wake_function);

                ctx->reader_contended = 1;

                add_wait_queue(&ctx->wq, &wait);
                ret = sk_wait_event(sk, &timeo,
                                    !READ_ONCE(ctx->reader_present), &wait);
                remove_wait_queue(&ctx->wq, &wait);

                if (timeo <= 0)
                        return -EAGAIN;
                if (signal_pending(current))
                        return sock_intr_errno(timeo);
                if (ret < 0)
                        return ret;
        }

        WRITE_ONCE(ctx->reader_present, 1);

        return 0;
}

static int tls_rx_reader_lock(struct sock *sk, struct tls_sw_context_rx *ctx,
                              bool nonblock)
{
        int err;

        lock_sock(sk);
        err = tls_rx_reader_acquire(sk, ctx, nonblock);
        if (err)
                release_sock(sk);
        return err;
}

static void tls_rx_reader_release(struct sock *sk, struct tls_sw_context_rx *ctx)
{
        if (unlikely(ctx->reader_contended)) {
                if (wq_has_sleeper(&ctx->wq))
                        wake_up(&ctx->wq);
                else
                        ctx->reader_contended = 0;

                WARN_ON_ONCE(!ctx->reader_present);
        }

        WRITE_ONCE(ctx->reader_present, 0);
}

static void tls_rx_reader_unlock(struct sock *sk, struct tls_sw_context_rx *ctx)
{
        tls_rx_reader_release(sk, ctx);
        release_sock(sk);
}

int tls_sw_recvmsg(struct sock *sk,
                   struct msghdr *msg,
                   size_t len,
                   int flags,
                   int *addr_len)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
        struct tls_prot_info *prot = &tls_ctx->prot_info;
        ssize_t decrypted = 0, async_copy_bytes = 0;
        struct sk_psock *psock;
        unsigned char control = 0;
        size_t flushed_at = 0;
        struct strp_msg *rxm;
        struct tls_msg *tlm;
        ssize_t copied = 0;
        ssize_t peeked = 0;
        bool async = false;
        int target, err;
        bool is_kvec = iov_iter_is_kvec(&msg->msg_iter);
        bool is_peek = flags & MSG_PEEK;
        bool rx_more = false;
        bool released = true;
        bool bpf_strp_enabled;
        bool zc_capable;

        if (unlikely(flags & MSG_ERRQUEUE))
                return sock_recv_errqueue(sk, msg, len, SOL_IP, IP_RECVERR);

        err = tls_rx_reader_lock(sk, ctx, flags & MSG_DONTWAIT);
        if (err < 0)
                return err;
        psock = sk_psock_get(sk);
        bpf_strp_enabled = sk_psock_strp_enabled(psock);

        /* If crypto failed the connection is broken */
        err = ctx->async_wait.err;
        if (err)
                goto end;

        /* Process pending decrypted records. It must be non-zero-copy */
        err = process_rx_list(ctx, msg, &control, 0, len, is_peek, &rx_more);
        if (err < 0)
                goto end;

        /* process_rx_list() will set @control if it processed any records */
        copied = err;
        if (len <= copied || rx_more ||
            (control && control != TLS_RECORD_TYPE_DATA))
                goto end;

        target = sock_rcvlowat(sk, flags & MSG_WAITALL, len);
        len = len - copied;

        zc_capable = !bpf_strp_enabled && !is_kvec && !is_peek &&
                ctx->zc_capable;
        decrypted = 0;
        while (len && (decrypted + copied < target || tls_strp_msg_ready(ctx))) {
                struct tls_decrypt_arg darg;
                int to_decrypt, chunk;

                err = tls_rx_rec_wait(sk, psock, flags & MSG_DONTWAIT,
                                      released);
                if (err <= 0) {
                        if (psock) {
                                chunk = sk_msg_recvmsg(sk, psock, msg, len,
                                                       flags);
                                if (chunk > 0) {
                                        decrypted += chunk;
                                        len -= chunk;
                                        continue;
                                }
                        }
                        goto recv_end;
                }

                memset(&darg.inargs, 0, sizeof(darg.inargs));

                rxm = strp_msg(tls_strp_msg(ctx));
                tlm = tls_msg(tls_strp_msg(ctx));

                to_decrypt = rxm->full_len - prot->overhead_size;

                if (zc_capable && to_decrypt <= len &&
                    tlm->control == TLS_RECORD_TYPE_DATA)
                        darg.zc = true;

                /* Do not use async mode if record is non-data */
                if (tlm->control == TLS_RECORD_TYPE_DATA && !bpf_strp_enabled)
                        darg.async = ctx->async_capable;
                else
                        darg.async = false;

                err = tls_rx_one_record(sk, msg, &darg);
                if (err < 0) {
                        tls_err_abort(sk, -EBADMSG);
                        goto recv_end;
                }

                async |= darg.async;

                /* If the type of records being processed is not known yet,
                 * set it to record type just dequeued. If it is already known,
                 * but does not match the record type just dequeued, go to end.
                 * We always get record type here since for tls1.2, record type
                 * is known just after record is dequeued from stream parser.
                 * For tls1.3, we disable async.
                 */
                err = tls_record_content_type(msg, tls_msg(darg.skb), &control);
                if (err <= 0) {
                        DEBUG_NET_WARN_ON_ONCE(darg.zc);
                        tls_rx_rec_done(ctx);
put_on_rx_list_err:
                        __skb_queue_tail(&ctx->rx_list, darg.skb);
                        goto recv_end;
                }

                /* periodically flush backlog, and feed strparser */
                released = tls_read_flush_backlog(sk, prot, len, to_decrypt,
                                                  decrypted + copied,
                                                  &flushed_at);

                /* TLS 1.3 may have updated the length by more than overhead */
                rxm = strp_msg(darg.skb);
                chunk = rxm->full_len;
                tls_rx_rec_done(ctx);

                if (!darg.zc) {
                        bool partially_consumed = chunk > len;
                        struct sk_buff *skb = darg.skb;

                        DEBUG_NET_WARN_ON_ONCE(darg.skb == ctx->strp.anchor);

                        if (async) {
                                /* TLS 1.2-only, to_decrypt must be text len */
                                chunk = min_t(int, to_decrypt, len);
                                async_copy_bytes += chunk;
put_on_rx_list:
                                decrypted += chunk;
                                len -= chunk;
                                __skb_queue_tail(&ctx->rx_list, skb);
                                if (unlikely(control != TLS_RECORD_TYPE_DATA))
                                        break;
                                continue;
                        }

                        if (bpf_strp_enabled) {
                                released = true;
                                err = sk_psock_tls_strp_read(psock, skb);
                                if (err != __SK_PASS) {
                                        rxm->offset = rxm->offset + rxm->full_len;
                                        rxm->full_len = 0;
                                        if (err == __SK_DROP)
                                                consume_skb(skb);
                                        continue;
                                }
                        }

                        if (partially_consumed)
                                chunk = len;

                        err = skb_copy_datagram_msg(skb, rxm->offset,
                                                    msg, chunk);
                        if (err < 0)
                                goto put_on_rx_list_err;

                        if (is_peek) {
                                peeked += chunk;
                                goto put_on_rx_list;
                        }

                        if (partially_consumed) {
                                rxm->offset += chunk;
                                rxm->full_len -= chunk;
                                goto put_on_rx_list;
                        }

                        consume_skb(skb);
                }

                decrypted += chunk;
                len -= chunk;

                /* Return full control message to userspace before trying
                 * to parse another message type
                 */
                msg->msg_flags |= MSG_EOR;
                if (control != TLS_RECORD_TYPE_DATA)
                        break;
        }

recv_end:
        if (async) {
                int ret;

                /* Wait for all previously submitted records to be decrypted */
                ret = tls_decrypt_async_wait(ctx);

                if (ret) {
                        if (err >= 0 || err == -EINPROGRESS)
                                err = ret;
                        goto end;
                }

                /* Drain records from the rx_list & copy if required */
                if (is_peek)
                        err = process_rx_list(ctx, msg, &control, copied + peeked,
                                              decrypted - peeked, is_peek, NULL);
                else
                        err = process_rx_list(ctx, msg, &control, 0,
                                              async_copy_bytes, is_peek, NULL);

                /* we could have copied less than we wanted, and possibly nothing */
                decrypted += max(err, 0) - async_copy_bytes;
        }

        copied += decrypted;

end:
        tls_rx_reader_unlock(sk, ctx);
        if (psock)
                sk_psock_put(sk, psock);
        return copied ? : err;
}

ssize_t tls_sw_splice_read(struct socket *sock,  loff_t *ppos,
                           struct pipe_inode_info *pipe,
                           size_t len, unsigned int flags)
{
        struct tls_context *tls_ctx = tls_get_ctx(sock->sk);
        struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
        struct strp_msg *rxm = NULL;
        struct sock *sk = sock->sk;
        struct tls_msg *tlm;
        struct sk_buff *skb;
        ssize_t copied = 0;
        int chunk;
        int err;

        err = tls_rx_reader_lock(sk, ctx, flags & SPLICE_F_NONBLOCK);
        if (err < 0)
                return err;

        if (!skb_queue_empty(&ctx->rx_list)) {
                skb = __skb_dequeue(&ctx->rx_list);
        } else {
                struct tls_decrypt_arg darg;

                err = tls_rx_rec_wait(sk, NULL, flags & SPLICE_F_NONBLOCK,
                                      true);
                if (err <= 0)
                        goto splice_read_end;

                memset(&darg.inargs, 0, sizeof(darg.inargs));

                err = tls_rx_one_record(sk, NULL, &darg);
                if (err < 0) {
                        tls_err_abort(sk, -EBADMSG);
                        goto splice_read_end;
                }

                tls_rx_rec_done(ctx);
                skb = darg.skb;
        }

        rxm = strp_msg(skb);
        tlm = tls_msg(skb);

        /* splice does not support reading control messages */
        if (tlm->control != TLS_RECORD_TYPE_DATA) {
                err = -EINVAL;
                goto splice_requeue;
        }

        chunk = min_t(unsigned int, rxm->full_len, len);
        copied = skb_splice_bits(skb, sk, rxm->offset, pipe, chunk, flags);
        if (copied < 0)
                goto splice_requeue;

        if (chunk < rxm->full_len) {
                rxm->offset += len;
                rxm->full_len -= len;
                goto splice_requeue;
        }

        consume_skb(skb);

splice_read_end:
        tls_rx_reader_unlock(sk, ctx);
        return copied ? : err;

splice_requeue:
        __skb_queue_head(&ctx->rx_list, skb);
        goto splice_read_end;
}

int tls_sw_read_sock(struct sock *sk, read_descriptor_t *desc,
                     sk_read_actor_t read_actor)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
        struct tls_prot_info *prot = &tls_ctx->prot_info;
        struct strp_msg *rxm = NULL;
        struct sk_buff *skb = NULL;
        struct sk_psock *psock;
        size_t flushed_at = 0;
        bool released = true;
        struct tls_msg *tlm;
        ssize_t copied = 0;
        ssize_t decrypted;
        int err, used;

        psock = sk_psock_get(sk);
        if (psock) {
                sk_psock_put(sk, psock);
                return -EINVAL;
        }
        err = tls_rx_reader_acquire(sk, ctx, true);
        if (err < 0)
                return err;

        /* If crypto failed the connection is broken */
        err = ctx->async_wait.err;
        if (err)
                goto read_sock_end;

        decrypted = 0;
        do {
                if (!skb_queue_empty(&ctx->rx_list)) {
                        skb = __skb_dequeue(&ctx->rx_list);
                        rxm = strp_msg(skb);
                        tlm = tls_msg(skb);
                } else {
                        struct tls_decrypt_arg darg;

                        err = tls_rx_rec_wait(sk, NULL, true, released);
                        if (err <= 0)
                                goto read_sock_end;

                        memset(&darg.inargs, 0, sizeof(darg.inargs));

                        err = tls_rx_one_record(sk, NULL, &darg);
                        if (err < 0) {
                                tls_err_abort(sk, -EBADMSG);
                                goto read_sock_end;
                        }

                        released = tls_read_flush_backlog(sk, prot, INT_MAX,
                                                          0, decrypted,
                                                          &flushed_at);
                        skb = darg.skb;
                        rxm = strp_msg(skb);
                        tlm = tls_msg(skb);
                        decrypted += rxm->full_len;

                        tls_rx_rec_done(ctx);
                }

                /* read_sock does not support reading control messages */
                if (tlm->control != TLS_RECORD_TYPE_DATA) {
                        err = -EINVAL;
                        goto read_sock_requeue;
                }

                used = read_actor(desc, skb, rxm->offset, rxm->full_len);
                if (used <= 0) {
                        if (!copied)
                                err = used;
                        goto read_sock_requeue;
                }
                copied += used;
                if (used < rxm->full_len) {
                        rxm->offset += used;
                        rxm->full_len -= used;
                        if (!desc->count)
                                goto read_sock_requeue;
                } else {
                        consume_skb(skb);
                        if (!desc->count)
                                skb = NULL;
                }
        } while (skb);

read_sock_end:
        tls_rx_reader_release(sk, ctx);
        return copied ? : err;

read_sock_requeue:
        __skb_queue_head(&ctx->rx_list, skb);
        goto read_sock_end;
}

bool tls_sw_sock_is_readable(struct sock *sk)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
        bool ingress_empty = true;
        struct sk_psock *psock;

        rcu_read_lock();
        psock = sk_psock(sk);
        if (psock)
                ingress_empty = list_empty(&psock->ingress_msg);
        rcu_read_unlock();

        return !ingress_empty || tls_strp_msg_ready(ctx) ||
                !skb_queue_empty(&ctx->rx_list);
}

int tls_rx_msg_size(struct tls_strparser *strp, struct sk_buff *skb)
{
        struct tls_context *tls_ctx = tls_get_ctx(strp->sk);
        struct tls_prot_info *prot = &tls_ctx->prot_info;
        char header[TLS_HEADER_SIZE + TLS_MAX_IV_SIZE];
        size_t cipher_overhead;
        size_t data_len = 0;
        int ret;

        /* Verify that we have a full TLS header, or wait for more data */
        if (strp->stm.offset + prot->prepend_size > skb->len)
                return 0;

        /* Sanity-check size of on-stack buffer. */
        if (WARN_ON(prot->prepend_size > sizeof(header))) {
                ret = -EINVAL;
                goto read_failure;
        }

        /* Linearize header to local buffer */
        ret = skb_copy_bits(skb, strp->stm.offset, header, prot->prepend_size);
        if (ret < 0)
                goto read_failure;

        strp->mark = header[0];

        data_len = ((header[4] & 0xFF) | (header[3] << 8));

        cipher_overhead = prot->tag_size;
        if (prot->version != TLS_1_3_VERSION &&
            prot->cipher_type != TLS_CIPHER_CHACHA20_POLY1305)
                cipher_overhead += prot->iv_size;

        if (data_len > TLS_MAX_PAYLOAD_SIZE + cipher_overhead +
            prot->tail_size) {
                ret = -EMSGSIZE;
                goto read_failure;
        }
        if (data_len < cipher_overhead) {
                ret = -EBADMSG;
                goto read_failure;
        }

        /* Note that both TLS1.3 and TLS1.2 use TLS_1_2 version here */
        if (header[1] != TLS_1_2_VERSION_MINOR ||
            header[2] != TLS_1_2_VERSION_MAJOR) {
                ret = -EINVAL;
                goto read_failure;
        }

        tls_device_rx_resync_new_rec(strp->sk, data_len + TLS_HEADER_SIZE,
                                     TCP_SKB_CB(skb)->seq + strp->stm.offset);
        return data_len + TLS_HEADER_SIZE;

read_failure:
        tls_strp_abort_strp(strp, ret);
        return ret;
}

void tls_rx_msg_ready(struct tls_strparser *strp)
{
        struct tls_sw_context_rx *ctx;

        ctx = container_of(strp, struct tls_sw_context_rx, strp);
        ctx->saved_data_ready(strp->sk);
}

static void tls_data_ready(struct sock *sk)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
        struct sk_psock *psock;
        gfp_t alloc_save;

        trace_sk_data_ready(sk);

        alloc_save = sk->sk_allocation;
        sk->sk_allocation = GFP_ATOMIC;
        tls_strp_data_ready(&ctx->strp);
        sk->sk_allocation = alloc_save;

        psock = sk_psock_get(sk);
        if (psock) {
                if (!list_empty(&psock->ingress_msg))
                        ctx->saved_data_ready(sk);
                sk_psock_put(sk, psock);
        }
}

void tls_sw_cancel_work_tx(struct tls_context *tls_ctx)
{
        struct tls_sw_context_tx *ctx = tls_sw_ctx_tx(tls_ctx);

        set_bit(BIT_TX_CLOSING, &ctx->tx_bitmask);
        set_bit(BIT_TX_SCHEDULED, &ctx->tx_bitmask);
        disable_delayed_work_sync(&ctx->tx_work.work);
}

void tls_sw_release_resources_tx(struct sock *sk)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_sw_context_tx *ctx = tls_sw_ctx_tx(tls_ctx);
        struct tls_rec *rec, *tmp;

        /* Wait for any pending async encryptions to complete */
        tls_encrypt_async_wait(ctx);

        tls_tx_records(sk, -1);

        /* Free up un-sent records in tx_list. First, free
         * the partially sent record if any at head of tx_list.
         */
        if (tls_ctx->partially_sent_record) {
                tls_free_partial_record(sk, tls_ctx);
                rec = list_first_entry(&ctx->tx_list,
                                       struct tls_rec, list);
                list_del(&rec->list);
                sk_msg_free(sk, &rec->msg_plaintext);
                kfree(rec);
        }

        list_for_each_entry_safe(rec, tmp, &ctx->tx_list, list) {
                list_del(&rec->list);
                sk_msg_free(sk, &rec->msg_encrypted);
                sk_msg_free(sk, &rec->msg_plaintext);
                kfree(rec);
        }

        crypto_free_aead(ctx->aead_send);
        tls_free_open_rec(sk);
}

void tls_sw_free_ctx_tx(struct tls_context *tls_ctx)
{
        struct tls_sw_context_tx *ctx = tls_sw_ctx_tx(tls_ctx);

        kfree(ctx);
}

void tls_sw_release_resources_rx(struct sock *sk)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);

        if (ctx->aead_recv) {
                __skb_queue_purge(&ctx->rx_list);
                crypto_free_aead(ctx->aead_recv);
                tls_strp_stop(&ctx->strp);
                /* If tls_sw_strparser_arm() was not called (cleanup paths)
                 * we still want to tls_strp_stop(), but sk->sk_data_ready was
                 * never swapped.
                 */
                if (ctx->saved_data_ready) {
                        write_lock_bh(&sk->sk_callback_lock);
                        sk->sk_data_ready = ctx->saved_data_ready;
                        write_unlock_bh(&sk->sk_callback_lock);
                }
        }
}

void tls_sw_strparser_done(struct tls_context *tls_ctx)
{
        struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);

        tls_strp_done(&ctx->strp);
}

void tls_sw_free_ctx_rx(struct tls_context *tls_ctx)
{
        struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);

        kfree(ctx);
}

void tls_sw_free_resources_rx(struct sock *sk)
{
        struct tls_context *tls_ctx = tls_get_ctx(sk);

        tls_sw_release_resources_rx(sk);
        tls_sw_free_ctx_rx(tls_ctx);
}

/* The work handler to transmitt the encrypted records in tx_list */
static void tx_work_handler(struct work_struct *work)
{
        struct delayed_work *delayed_work = to_delayed_work(work);
        struct tx_work *tx_work = container_of(delayed_work,
                                               struct tx_work, work);
        struct sock *sk = tx_work->sk;
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct tls_sw_context_tx *ctx;

        if (unlikely(!tls_ctx))
                return;

        ctx = tls_sw_ctx_tx(tls_ctx);
        if (test_bit(BIT_TX_CLOSING, &ctx->tx_bitmask))
                return;

        if (!test_and_clear_bit(BIT_TX_SCHEDULED, &ctx->tx_bitmask))
                return;

        if (mutex_trylock(&tls_ctx->tx_lock)) {
                lock_sock(sk);
                tls_tx_records(sk, -1);
                release_sock(sk);
                mutex_unlock(&tls_ctx->tx_lock);
        } else if (!test_and_set_bit(BIT_TX_SCHEDULED, &ctx->tx_bitmask)) {
                /* Someone is holding the tx_lock, they will likely run Tx
                 * and cancel the work on their way out of the lock section.
                 * Schedule a long delay just in case.
                 */
                schedule_delayed_work(&ctx->tx_work.work, msecs_to_jiffies(10));
        }
}

static bool tls_is_tx_ready(struct tls_sw_context_tx *ctx)
{
        struct tls_rec *rec;

        rec = list_first_entry_or_null(&ctx->tx_list, struct tls_rec, list);
        if (!rec)
                return false;

        return READ_ONCE(rec->tx_ready);
}

void tls_sw_write_space(struct sock *sk, struct tls_context *ctx)
{
        struct tls_sw_context_tx *tx_ctx = tls_sw_ctx_tx(ctx);

        /* Schedule the transmission if tx list is ready */
        if (tls_is_tx_ready(tx_ctx) &&
            !test_and_set_bit(BIT_TX_SCHEDULED, &tx_ctx->tx_bitmask))
                schedule_delayed_work(&tx_ctx->tx_work.work, 0);
}

void tls_sw_strparser_arm(struct sock *sk, struct tls_context *tls_ctx)
{
        struct tls_sw_context_rx *rx_ctx = tls_sw_ctx_rx(tls_ctx);

        write_lock_bh(&sk->sk_callback_lock);
        rx_ctx->saved_data_ready = sk->sk_data_ready;
        sk->sk_data_ready = tls_data_ready;
        write_unlock_bh(&sk->sk_callback_lock);
}

void tls_update_rx_zc_capable(struct tls_context *tls_ctx)
{
        struct tls_sw_context_rx *rx_ctx = tls_sw_ctx_rx(tls_ctx);

        rx_ctx->zc_capable = tls_ctx->rx_no_pad ||
                tls_ctx->prot_info.version != TLS_1_3_VERSION;
}

static struct tls_sw_context_tx *init_ctx_tx(struct tls_context *ctx, struct sock *sk)
{
        struct tls_sw_context_tx *sw_ctx_tx;

        if (!ctx->priv_ctx_tx) {
                sw_ctx_tx = kzalloc_obj(*sw_ctx_tx);
                if (!sw_ctx_tx)
                        return NULL;
        } else {
                sw_ctx_tx = ctx->priv_ctx_tx;
        }

        crypto_init_wait(&sw_ctx_tx->async_wait);
        atomic_set(&sw_ctx_tx->encrypt_pending, 1);
        INIT_LIST_HEAD(&sw_ctx_tx->tx_list);
        INIT_DELAYED_WORK(&sw_ctx_tx->tx_work.work, tx_work_handler);
        sw_ctx_tx->tx_work.sk = sk;

        return sw_ctx_tx;
}

static struct tls_sw_context_rx *init_ctx_rx(struct tls_context *ctx)
{
        struct tls_sw_context_rx *sw_ctx_rx;

        if (!ctx->priv_ctx_rx) {
                sw_ctx_rx = kzalloc_obj(*sw_ctx_rx);
                if (!sw_ctx_rx)
                        return NULL;
        } else {
                sw_ctx_rx = ctx->priv_ctx_rx;
        }

        crypto_init_wait(&sw_ctx_rx->async_wait);
        atomic_set(&sw_ctx_rx->decrypt_pending, 1);
        init_waitqueue_head(&sw_ctx_rx->wq);
        skb_queue_head_init(&sw_ctx_rx->rx_list);
        skb_queue_head_init(&sw_ctx_rx->async_hold);

        return sw_ctx_rx;
}

int init_prot_info(struct tls_prot_info *prot,
                   const struct tls_crypto_info *crypto_info,
                   const struct tls_cipher_desc *cipher_desc)
{
        u16 nonce_size = cipher_desc->nonce;

        if (crypto_info->version == TLS_1_3_VERSION) {
                nonce_size = 0;
                prot->aad_size = TLS_HEADER_SIZE;
                prot->tail_size = 1;
        } else {
                prot->aad_size = TLS_AAD_SPACE_SIZE;
                prot->tail_size = 0;
        }

        /* Sanity-check the sizes for stack allocations. */
        if (nonce_size > TLS_MAX_IV_SIZE || prot->aad_size > TLS_MAX_AAD_SIZE)
                return -EINVAL;

        prot->version = crypto_info->version;
        prot->cipher_type = crypto_info->cipher_type;
        prot->prepend_size = TLS_HEADER_SIZE + nonce_size;
        prot->tag_size = cipher_desc->tag;
        prot->overhead_size = prot->prepend_size + prot->tag_size + prot->tail_size;
        prot->iv_size = cipher_desc->iv;
        prot->salt_size = cipher_desc->salt;
        prot->rec_seq_size = cipher_desc->rec_seq;

        return 0;
}

static void tls_finish_key_update(struct sock *sk, struct tls_context *tls_ctx)
{
        struct tls_sw_context_rx *ctx = tls_ctx->priv_ctx_rx;

        WRITE_ONCE(ctx->key_update_pending, false);
        /* wake-up pre-existing poll() */
        ctx->saved_data_ready(sk);
}

int tls_set_sw_offload(struct sock *sk, int tx,
                       struct tls_crypto_info *new_crypto_info)
{
        struct tls_crypto_info *crypto_info, *src_crypto_info;
        struct tls_sw_context_tx *sw_ctx_tx = NULL;
        struct tls_sw_context_rx *sw_ctx_rx = NULL;
        const struct tls_cipher_desc *cipher_desc;
        char *iv, *rec_seq, *key, *salt;
        struct cipher_context *cctx;
        struct tls_prot_info *prot;
        struct crypto_aead **aead;
        struct tls_context *ctx;
        struct crypto_tfm *tfm;
        int rc = 0;

        ctx = tls_get_ctx(sk);
        prot = &ctx->prot_info;

        /* new_crypto_info != NULL means rekey */
        if (!new_crypto_info) {
                if (tx) {
                        ctx->priv_ctx_tx = init_ctx_tx(ctx, sk);
                        if (!ctx->priv_ctx_tx)
                                return -ENOMEM;
                } else {
                        ctx->priv_ctx_rx = init_ctx_rx(ctx);
                        if (!ctx->priv_ctx_rx)
                                return -ENOMEM;
                }
        }

        if (tx) {
                sw_ctx_tx = ctx->priv_ctx_tx;
                crypto_info = &ctx->crypto_send.info;
                cctx = &ctx->tx;
                aead = &sw_ctx_tx->aead_send;
        } else {
                sw_ctx_rx = ctx->priv_ctx_rx;
                crypto_info = &ctx->crypto_recv.info;
                cctx = &ctx->rx;
                aead = &sw_ctx_rx->aead_recv;
        }

        src_crypto_info = new_crypto_info ?: crypto_info;

        cipher_desc = get_cipher_desc(src_crypto_info->cipher_type);
        if (!cipher_desc) {
                rc = -EINVAL;
                goto free_priv;
        }

        rc = init_prot_info(prot, src_crypto_info, cipher_desc);
        if (rc)
                goto free_priv;

        iv = crypto_info_iv(src_crypto_info, cipher_desc);
        key = crypto_info_key(src_crypto_info, cipher_desc);
        salt = crypto_info_salt(src_crypto_info, cipher_desc);
        rec_seq = crypto_info_rec_seq(src_crypto_info, cipher_desc);

        if (!*aead) {
                *aead = crypto_alloc_aead(cipher_desc->cipher_name, 0, 0);
                if (IS_ERR(*aead)) {
                        rc = PTR_ERR(*aead);
                        *aead = NULL;
                        goto free_priv;
                }
        }

        ctx->push_pending_record = tls_sw_push_pending_record;

        /* setkey is the last operation that could fail during a
         * rekey. if it succeeds, we can start modifying the
         * context.
         */
        rc = crypto_aead_setkey(*aead, key, cipher_desc->key);
        if (rc) {
                if (new_crypto_info)
                        goto out;
                else
                        goto free_aead;
        }

        if (!new_crypto_info) {
                rc = crypto_aead_setauthsize(*aead, prot->tag_size);
                if (rc)
                        goto free_aead;
        }

        if (!tx && !new_crypto_info) {
                tfm = crypto_aead_tfm(sw_ctx_rx->aead_recv);

                tls_update_rx_zc_capable(ctx);
                sw_ctx_rx->async_capable =
                        src_crypto_info->version != TLS_1_3_VERSION &&
                        !!(tfm->__crt_alg->cra_flags & CRYPTO_ALG_ASYNC);

                rc = tls_strp_init(&sw_ctx_rx->strp, sk);
                if (rc)
                        goto free_aead;
        }

        memcpy(cctx->iv, salt, cipher_desc->salt);
        memcpy(cctx->iv + cipher_desc->salt, iv, cipher_desc->iv);
        memcpy(cctx->rec_seq, rec_seq, cipher_desc->rec_seq);

        if (new_crypto_info) {
                unsafe_memcpy(crypto_info, new_crypto_info,
                              cipher_desc->crypto_info,
                              /* size was checked in do_tls_setsockopt_conf */);
                memzero_explicit(new_crypto_info, cipher_desc->crypto_info);
                if (!tx)
                        tls_finish_key_update(sk, ctx);
        }

        goto out;

free_aead:
        crypto_free_aead(*aead);
        *aead = NULL;
free_priv:
        if (!new_crypto_info) {
                if (tx) {
                        kfree(ctx->priv_ctx_tx);
                        ctx->priv_ctx_tx = NULL;
                } else {
                        kfree(ctx->priv_ctx_rx);
                        ctx->priv_ctx_rx = NULL;
                }
        }
out:
        return rc;
}