text: /*
   * Copyright 1995-2018 The Opentls Project Authors. All Rights Reserved.
   *
   * Licensed under the Apache License 2.0 (the "License").  You may not use
   * this file except in compliance with the License.  You can obtain a copy
   * in the file LICENSE in the source distribution or at
   * https://www.opentls.org/source/license.html
   */
  
  #include <stdio.h>
  #include <limits.h>
  #include <errno.h>
  #include "../tls_local.h"
  #include <opentls/evp.h>
  #include <opentls/buffer.h>
  #include <opentls/rand.h>
  #include "record_local.h"
  #include "internal/packet.h"
  
  #if     defined(OPENtls_SMALL_FOOTPRINT) || \
          !(      defined(AES_ASM) &&     ( \
                  defined(__x86_64)       || defined(__x86_64__)  || \
                  defined(_M_AMD64)       || defined(_M_X64)      ) \
          )
  # undef EVP_CIPH_FLAG_TLS1_1_MULTIBLOCK
  # define EVP_CIPH_FLAG_TLS1_1_MULTIBLOCK 0
  #endif
  
  void RECORD_LAYER_init(RECORD_LAYER *rl, tls *s)
  {
      rl->s = s;
      RECORD_LAYER_set_first_record(&s->rlayer);
      tls3_RECORD_clear(rl->rrec, tls_MAX_PIPELINES);
  }
  
  void RECORD_LAYER_clear(RECORD_LAYER *rl)
  {
      rl->rstate = tls_ST_READ_HEADER;
  
      /*
       * Do I need to clear read_ahead? As far as I can tell read_ahead did not
       * previously get reset by tls_clear...so I'll keep it that way..but is
       * that right?
       */
  
      rl->packet = NULL;
      rl->packet_length = 0;
      rl->wnum = 0;
      memset(rl->handshake_fragment, 0, sizeof(rl->handshake_fragment));
      rl->handshake_fragment_len = 0;
      rl->wpend_tot = 0;
      rl->wpend_type = 0;
      rl->wpend_ret = 0;
      rl->wpend_buf = NULL;
  
      tls3_BUFFER_clear(&rl->rbuf);
      tls3_release_write_buffer(rl->s);
      rl->numrpipes = 0;
      tls3_RECORD_clear(rl->rrec, tls_MAX_PIPELINES);
  
      RECORD_LAYER_reset_read_sequence(rl);
      RECORD_LAYER_reset_write_sequence(rl);
  
      if (rl->d)
          DTLS_RECORD_LAYER_clear(rl);
  }
  
  void RECORD_LAYER_release(RECORD_LAYER *rl)
  {
      if (tls3_BUFFER_is_initialised(&rl->rbuf))
          tls3_release_read_buffer(rl->s);
      if (rl->numwpipes > 0)
          tls3_release_write_buffer(rl->s);
      tls3_RECORD_release(rl->rrec, tls_MAX_PIPELINES);
  }
  
  /* Checks if we have unprocessed read ahead data pending */
  int RECORD_LAYER_read_pending(const RECORD_LAYER *rl)
  {
      return tls3_BUFFER_get_left(&rl->rbuf) != 0;
  }
  
  /* Checks if we have decrypted unread record data pending */
  int RECORD_LAYER_processed_read_pending(const RECORD_LAYER *rl)
  {
      size_t curr_rec = 0, num_recs = RECORD_LAYER_get_numrpipes(rl);
      const tls3_RECORD *rr = rl->rrec;
  
      while (curr_rec < num_recs && tls3_RECORD_is_read(&rr[curr_rec]))
          curr_rec++;
  
      return curr_rec < num_recs;
  }
  
  int RECORD_LAYER_write_pending(const RECORD_LAYER *rl)
  {
      return (rl->numwpipes > 0)
          && tls3_BUFFER_get_left(&rl->wbuf[rl->numwpipes - 1]) != 0;
  }
  
  void RECORD_LAYER_reset_read_sequence(RECORD_LAYER *rl)
  {
      memset(rl->read_sequence, 0, sizeof(rl->read_sequence));
  }
  
  void RECORD_LAYER_reset_write_sequence(RECORD_LAYER *rl)
  {
      memset(rl->write_sequence, 0, sizeof(rl->write_sequence));
  }
  
  size_t tls3_pending(const tls *s)
  {
      size_t i, num = 0;
  
      if (s->rlayer.rstate == tls_ST_READ_BODY)
          return 0;
  
      for (i = 0; i < RECORD_LAYER_get_numrpipes(&s->rlayer); i++) {
          if (tls3_RECORD_get_type(&s->rlayer.rrec[i])
              != tls3_RT_APPLICATION_DATA)
              return 0;
          num += tls3_RECORD_get_length(&s->rlayer.rrec[i]);
      }
  
      return num;
  }
  
  void tls_CTX_set_default_read_buffer_len(tls_CTX *ctx, size_t len)
  {
      ctx->default_read_buf_len = len;
  }
  
  void tls_set_default_read_buffer_len(tls *s, size_t len)
  {
      tls3_BUFFER_set_default_len(RECORD_LAYER_get_rbuf(&s->rlayer), len);
  }
  
  const char *tls_rstate_string_long(const tls *s)
  {
      switch (s->rlayer.rstate) {
      case tls_ST_READ_HEADER:
          return "read header";
      case tls_ST_READ_BODY:
          return "read body";
      case tls_ST_READ_DONE:
          return "read done";
      default:
          return "unknown";
      }
  }
  
  const char *tls_rstate_string(const tls *s)
  {
      switch (s->rlayer.rstate) {
      case tls_ST_READ_HEADER:
          return "RH";
      case tls_ST_READ_BODY:
          return "RB";
      case tls_ST_READ_DONE:
          return "RD";
      default:
          return "unknown";
      }
  }
  
  /*
   * Return values are as per tls_read()
   */
  int tls3_read_n(tls *s, size_t n, size_t max, int extend, int clearold,
                  size_t *readbytes)
  {
      /*
       * If extend == 0, obtain new n-byte packet; if extend == 1, increase
       * packet by another n bytes. The packet will be in the sub-array of
       * s->s3.rbuf.buf specified by s->packet and s->packet_length. (If
       * s->rlayer.read_ahead is set, 'max' bytes may be stored in rbuf [plus
       * s->packet_length bytes if extend == 1].)
       * if clearold == 1, move the packet to the start of the buffer; if
       * clearold == 0 then leave any old packets where they were
       */
      size_t len, left, align = 0;
      unsigned char *pkt;
      tls3_BUFFER *rb;
  
      if (n == 0)
          return 0;
  
      rb = &s->rlayer.rbuf;
      if (rb->buf == NULL)
          if (!tls3_setup_read_buffer(s)) {
              /* tlsfatal() already called */
              return -1;
          }
  
      left = rb->left;
  #if defined(tls3_ALIGN_PAYLOAD) && tls3_ALIGN_PAYLOAD!=0
      align = (size_t)rb->buf + tls3_RT_HEADER_LENGTH;
      align = tls3_ALIGN_PAYLOAD - 1 - ((align - 1) % tls3_ALIGN_PAYLOAD);
  #endif
  
      if (!extend) {
          /* start with empty packet ... */
          if (left == 0)
              rb->offset = align;
          else if (align != 0 && left >= tls3_RT_HEADER_LENGTH) {
              /*
               * check if next packet length is large enough to justify payload
               * alignment...
               */
              pkt = rb->buf + rb->offset;
              if (pkt[0] == tls3_RT_APPLICATION_DATA
                  && (pkt[3] << 8 | pkt[4]) >= 128) {
                  /*
                   * Note that even if packet is corrupted and its length field
                   * is insane, we can only be led to wrong decision about
                   * whether memmove will occur or not. Header values has no
                   * effect on memmove arguments and therefore no buffer
                   * overrun can be triggered.
                   */
                  memmove(rb->buf + align, pkt, left);
                  rb->offset = align;
              }
          }
          s->rlayer.packet = rb->buf + rb->offset;
          s->rlayer.packet_length = 0;
          /* ... now we can act as if 'extend' was set */
      }
  
      len = s->rlayer.packet_length;
      pkt = rb->buf + align;
      /*
       * Move any available bytes to front of buffer: 'len' bytes already
       * pointed to by 'packet', 'left' extra ones at the end
       */
      if (s->rlayer.packet != pkt && clearold == 1) {
          memmove(pkt, s->rlayer.packet, len + left);
          s->rlayer.packet = pkt;
          rb->offset = len + align;
      }
  
      /*
       * For DTLS/UDP reads should not span multiple packets because the read
       * operation returns the whole packet at once (as long as it fits into
       * the buffer).
       */
      if (tls_IS_DTLS(s)) {
          if (left == 0 && extend)
              return 0;
          if (left > 0 && n > left)
              n = left;
      }
  
      /* if there is enough in the buffer from a previous read, take some */
      if (left >= n) {
          s->rlayer.packet_length += n;
          rb->left = left - n;
          rb->offset += n;
          *readbytes = n;
          return 1;
      }
  
      /* else we need to read more data */
  
      if (n > rb->len - rb->offset) {
          /* does not happen */
          tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_tls3_READ_N,
                   ERR_R_INTERNAL_ERROR);
          return -1;
      }
  
      /*
       * Ktls always reads full records.
       * Also, we always act like read_ahead is set for DTLS.
       */
      if (!BIO_get_ktls_recv(s->rbio) && !s->rlayer.read_ahead
          && !tls_IS_DTLS(s)) {
          /* ignore max parameter */
          max = n;
      } else {
          if (max < n)
              max = n;
          if (max > rb->len - rb->offset)
              max = rb->len - rb->offset;
      }
  
      while (left < n) {
          size_t bioread = 0;
          int ret;
  
          /*
           * Now we have len+left bytes at the front of s->s3.rbuf.buf and
           * need to read in more until we have len+n (up to len+max if
           * possible)
           */
  
          clear_sys_error();
          if (s->rbio != NULL) {
              s->rwstate = tls_READING;
              /* TODO(size_t): Convert this function */
              ret = BIO_read(s->rbio, pkt + len + left, max - left);
              if (ret >= 0)
                  bioread = ret;
          } else {
              tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_tls3_READ_N,
                       tls_R_READ_BIO_NOT_SET);
              ret = -1;
          }
  
          if (ret <= 0) {
              rb->left = left;
              if (s->mode & tls_MODE_RELEASE_BUFFERS && !tls_IS_DTLS(s))
                  if (len + left == 0)
                      tls3_release_read_buffer(s);
              return ret;
          }
          left += bioread;
          /*
           * reads should *never* span multiple packets for DTLS because the
           * underlying transport protocol is message oriented as opposed to
           * byte oriented as in the TLS case.
           */
          if (tls_IS_DTLS(s)) {
              if (n > left)
                  n = left;       /* makes the while condition false */
          }
      }
  
      /* done reading, now the book-keeping */
      rb->offset += n;
      rb->left = left - n;
      s->rlayer.packet_length += n;
      s->rwstate = tls_NOTHING;
      *readbytes = n;
      return 1;
  }
  
  /*
   * Call this to write data in records of type 'type' It will return <= 0 if
   * not all data has been sent or non-blocking IO.
   */
  int tls3_write_bytes(tls *s, int type, const void *buf_, size_t len,
                       size_t *written)
  {
      const unsigned char *buf = buf_;
      size_t tot;
      size_t n, max_send_fragment, split_send_fragment, maxpipes;
  #if !defined(OPENtls_NO_MULTIBLOCK) && EVP_CIPH_FLAG_TLS1_1_MULTIBLOCK
      size_t nw;
  #endif
      tls3_BUFFER *wb = &s->rlayer.wbuf[0];
      int i;
      size_t tmpwrit;
  
      s->rwstate = tls_NOTHING;
      tot = s->rlayer.wnum;
      /*
       * ensure that if we end up with a smaller value of data to write out
       * than the original len from a write which didn't complete for
       * non-blocking I/O and also somehow ended up avoiding the check for
       * this in tls3_write_pending/tls_R_BAD_WRITE_RETRY as it must never be
       * possible to end up with (len-tot) as a large number that will then
       * promptly send beyond the end of the users buffer ... so we trap and
       * report the error in a way the user will notice
       */
      if ((len < s->rlayer.wnum)
          || ((wb->left != 0) && (len < (s->rlayer.wnum + s->rlayer.wpend_tot)))) {
          tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_tls3_WRITE_BYTES,
                   tls_R_BAD_LENGTH);
          return -1;
      }
  
      if (s->early_data_state == tls_EARLY_DATA_WRITING
              && !early_data_count_ok(s, len, 0, 1)) {
          /* tlsfatal() already called */
          return -1;
      }
  
      s->rlayer.wnum = 0;
  
      /*
       * If we are supposed to be sending a KeyUpdate then go into init unless we
       * have writes pending - in which case we should finish doing that first.
       */
      if (wb->left == 0 && s->key_update != tls_KEY_UPDATE_NONE)
          otls_statem_set_in_init(s, 1);
  
      /*
       * When writing early data on the server side we could be "in_init" in
       * between receiving the EoED and the CF - but we don't want to handle those
       * messages yet.
       */
      if (tls_in_init(s) && !otls_statem_get_in_handshake(s)
              && s->early_data_state != tls_EARLY_DATA_UNAUTH_WRITING) {
          i = s->handshake_func(s);
          /* tlsfatal() already called */
          if (i < 0)
              return i;
          if (i == 0) {
              return -1;
          }
      }
  
      /*
       * first check if there is a tls3_BUFFER still being written out.  This
       * will happen with non blocking IO
       */
      if (wb->left != 0) {
          /* tlsfatal() already called if appropriate */
          i = tls3_write_pending(s, type, &buf[tot], s->rlayer.wpend_tot,
                                 &tmpwrit);
          if (i <= 0) {
              /* XXX should we tls3_release_write_buffer if i<0? */
              s->rlayer.wnum = tot;
              return i;
          }
          tot += tmpwrit;               /* this might be last fragment */
      }
  #if !defined(OPENtls_NO_MULTIBLOCK) && EVP_CIPH_FLAG_TLS1_1_MULTIBLOCK
      /*
       * Depending on platform multi-block can deliver several *times*
       * better performance. Downside is that it has to allocate
       * jumbo buffer to accommodate up to 8 records, but the
       * compromise is considered worthy.
       */
      if (type == tls3_RT_APPLICATION_DATA &&
          len >= 4 * (max_send_fragment = tls_get_max_send_fragment(s)) &&
          s->compress == NULL && s->msg_callback == NULL &&
          !tls_WRITE_ETM(s) && tls_USE_EXPLICIT_IV(s) &&
          (BIO_get_ktls_send(s->wbio) == 0) &&
          EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(s->enc_write_ctx)) &
          EVP_CIPH_FLAG_TLS1_1_MULTIBLOCK) {
          unsigned char aad[13];
          EVP_CTRL_TLS1_1_MULTIBLOCK_PARAM mb_param;
          size_t packlen;
          int packleni;
  
          /* minimize address aliasing conflicts */
          if ((max_send_fragment & 0xfff) == 0)
              max_send_fragment -= 512;
  
          if (tot == 0 || wb->buf == NULL) { /* allocate jumbo buffer */
              tls3_release_write_buffer(s);
  
              packlen = EVP_CIPHER_CTX_ctrl(s->enc_write_ctx,
                                            EVP_CTRL_TLS1_1_MULTIBLOCK_MAX_BUFSIZE,
                                            (int)max_send_fragment, NULL);
  
              if (len >= 8 * max_send_fragment)
                  packlen *= 8;
              else
                  packlen *= 4;
  
              if (!tls3_setup_write_buffer(s, 1, packlen)) {
                  /* tlsfatal() already called */
                  return -1;
              }
          } else if (tot == len) { /* done? */
              /* free jumbo buffer */
              tls3_release_write_buffer(s);
              *written = tot;
              return 1;
          }
  
          n = (len - tot);
          for (;;) {
              if (n < 4 * max_send_fragment) {
                  /* free jumbo buffer */
                  tls3_release_write_buffer(s);
                  break;
              }
  
              if (s->s3.alert_dispatch) {
                  i = s->method->tls_dispatch_alert(s);
                  if (i <= 0) {
                      /* tlsfatal() already called if appropriate */
                      s->rlayer.wnum = tot;
                      return i;
                  }
              }
  
              if (n >= 8 * max_send_fragment)
                  nw = max_send_fragment * (mb_param.interleave = 8);
              else
                  nw = max_send_fragment * (mb_param.interleave = 4);
  
              memcpy(aad, s->rlayer.write_sequence, 8);
              aad[8] = type;
              aad[9] = (unsigned char)(s->version >> 8);
              aad[10] = (unsigned char)(s->version);
              aad[11] = 0;
              aad[12] = 0;
              mb_param.out = NULL;
              mb_param.inp = aad;
              mb_param.len = nw;
  
              packleni = EVP_CIPHER_CTX_ctrl(s->enc_write_ctx,
                                            EVP_CTRL_TLS1_1_MULTIBLOCK_AAD,
                                            sizeof(mb_param), &mb_param);
              packlen = (size_t)packleni;
              if (packleni <= 0 || packlen > wb->len) { /* never happens */
                  /* free jumbo buffer */
                  tls3_release_write_buffer(s);
                  break;
              }
  
              mb_param.out = wb->buf;
              mb_param.inp = &buf[tot];
              mb_param.len = nw;
  
              if (EVP_CIPHER_CTX_ctrl(s->enc_write_ctx,
                                      EVP_CTRL_TLS1_1_MULTIBLOCK_ENCRYPT,
                                      sizeof(mb_param), &mb_param) <= 0)
                  return -1;
  
              s->rlayer.write_sequence[7] += mb_param.interleave;
              if (s->rlayer.write_sequence[7] < mb_param.interleave) {
                  int j = 6;
                  while (j >= 0 && (++s->rlayer.write_sequence[j--]) == 0) ;
              }
  
              wb->offset = 0;
              wb->left = packlen;
  
              s->rlayer.wpend_tot = nw;
              s->rlayer.wpend_buf = &buf[tot];
              s->rlayer.wpend_type = type;
              s->rlayer.wpend_ret = nw;
  
              i = tls3_write_pending(s, type, &buf[tot], nw, &tmpwrit);
              if (i <= 0) {
                  /* tlsfatal() already called if appropriate */
                  if (i < 0 && (!s->wbio || !BIO_should_retry(s->wbio))) {
                      /* free jumbo buffer */
                      tls3_release_write_buffer(s);
                  }
                  s->rlayer.wnum = tot;
                  return i;
              }
              if (tmpwrit == n) {
                  /* free jumbo buffer */
                  tls3_release_write_buffer(s);
                  *written = tot + tmpwrit;
                  return 1;
              }
              n -= tmpwrit;
              tot += tmpwrit;
          }
      } else
  #endif  /* !defined(OPENtls_NO_MULTIBLOCK) && EVP_CIPH_FLAG_TLS1_1_MULTIBLOCK */
      if (tot == len) {           /* done? */
          if (s->mode & tls_MODE_RELEASE_BUFFERS && !tls_IS_DTLS(s))
              tls3_release_write_buffer(s);
  
          *written = tot;
          return 1;
      }
  
      n = (len - tot);
  
      max_send_fragment = tls_get_max_send_fragment(s);
      split_send_fragment = tls_get_split_send_fragment(s);
      /*
       * If max_pipelines is 0 then this means "undefined" and we default to
       * 1 pipeline. Similarly if the cipher does not support pipelined
       * processing then we also only use 1 pipeline, or if we're not using
       * explicit IVs
       */
      maxpipes = s->max_pipelines;
      if (maxpipes > tls_MAX_PIPELINES) {
          /*
           * We should have prevented this when we set max_pipelines so we
           * shouldn't get here
           */
          tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_tls3_WRITE_BYTES,
                   ERR_R_INTERNAL_ERROR);
          return -1;
      }
      if (maxpipes == 0
          || s->enc_write_ctx == NULL
          || !(EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(s->enc_write_ctx))
               & EVP_CIPH_FLAG_PIPELINE)
          || !tls_USE_EXPLICIT_IV(s))
          maxpipes = 1;
      if (max_send_fragment == 0 || split_send_fragment == 0
          || split_send_fragment > max_send_fragment) {
          /*
           * We should have prevented this when we set/get the split and max send
           * fragments so we shouldn't get here
           */
          tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_tls3_WRITE_BYTES,
                   ERR_R_INTERNAL_ERROR);
          return -1;
      }
  
      for (;;) {
          size_t pipelens[tls_MAX_PIPELINES], tmppipelen, remain;
          size_t numpipes, j;
  
          if (n == 0)
              numpipes = 1;
          else
              numpipes = ((n - 1) / split_send_fragment) + 1;
          if (numpipes > maxpipes)
              numpipes = maxpipes;
  
          if (n / numpipes >= max_send_fragment) {
              /*
               * We have enough data to completely fill all available
               * pipelines
               */
              for (j = 0; j < numpipes; j++) {
                  pipelens[j] = max_send_fragment;
              }
          } else {
              /* We can partially fill all available pipelines */
              tmppipelen = n / numpipes;
              remain = n % numpipes;
              for (j = 0; j < numpipes; j++) {
                  pipelens[j] = tmppipelen;
                  if (j < remain)
                      pipelens[j]++;
              }
          }
  
          i = do_tls3_write(s, type, &(buf[tot]), pipelens, numpipes, 0,
                            &tmpwrit);
          if (i <= 0) {
              /* tlsfatal() already called if appropriate */
              /* XXX should we tls3_release_write_buffer if i<0? */
              s->rlayer.wnum = tot;
              return i;
          }
  
          if (tmpwrit == n ||
              (type == tls3_RT_APPLICATION_DATA &&
               (s->mode & tls_MODE_ENABLE_PARTIAL_WRITE))) {
              /*
               * next chunk of data should get another prepended empty fragment
               * in ciphersuites with known-IV weakness:
               */
              s->s3.empty_fragment_done = 0;
  
              if (tmpwrit == n
                      && (s->mode & tls_MODE_RELEASE_BUFFERS) != 0
                      && !tls_IS_DTLS(s))
                  tls3_release_write_buffer(s);
  
              *written = tot + tmpwrit;
              return 1;
          }
  
          n -= tmpwrit;
          tot += tmpwrit;
      }
  }
  
  int do_tls3_write(tls *s, int type, const unsigned char *buf,
                    size_t *pipelens, size_t numpipes,
                    int create_empty_fragment, size_t *written)
  {
      WPACKET pkt[tls_MAX_PIPELINES];
      tls3_RECORD wr[tls_MAX_PIPELINES];
      WPACKET *thispkt;
      tls3_RECORD *thiswr;
      unsigned char *recordstart;
      int i, mac_size, clear = 0;
      size_t prefix_len = 0;
      int eivlen = 0;
      size_t align = 0;
      tls3_BUFFER *wb;
      tls_SESSION *sess;
      size_t totlen = 0, len, wpinited = 0;
      size_t j;
  
      for (j = 0; j < numpipes; j++)
          totlen += pipelens[j];
      /*
       * first check if there is a tls3_BUFFER still being written out.  This
       * will happen with non blocking IO
       */
      if (RECORD_LAYER_write_pending(&s->rlayer)) {
          /* Calls tlsfatal() as required */
          return tls3_write_pending(s, type, buf, totlen, written);
      }
  
      /* If we have an alert to send, lets send it */
      if (s->s3.alert_dispatch) {
          i = s->method->tls_dispatch_alert(s);
          if (i <= 0) {
              /* tlsfatal() already called if appropriate */
              return i;
          }
          /* if it went, fall through and send more stuff */
      }
  
      if (s->rlayer.numwpipes < numpipes) {
          if (!tls3_setup_write_buffer(s, numpipes, 0)) {
              /* tlsfatal() already called */
              return -1;
          }
      }
  
      if (totlen == 0 && !create_empty_fragment)
          return 0;
  
      sess = s->session;
  
      if ((sess == NULL) ||
          (s->enc_write_ctx == NULL) || (EVP_MD_CTX_md(s->write_hash) == NULL)) {
          clear = s->enc_write_ctx ? 0 : 1; /* must be AEAD cipher */
          mac_size = 0;
      } else {
          /* TODO(siz_t): Convert me */
          mac_size = EVP_MD_CTX_size(s->write_hash);
          if (mac_size < 0) {
              tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                       ERR_R_INTERNAL_ERROR);
              goto err;
          }
      }
  
      /*
       * 'create_empty_fragment' is true only when this function calls itself
       */
      if (!clear && !create_empty_fragment && !s->s3.empty_fragment_done) {
          /*
           * countermeasure against known-IV weakness in CBC ciphersuites (see
           * http://www.opentls.org/~bodo/tls-cbc.txt)
           */
  
          if (s->s3.need_empty_fragments && type == tls3_RT_APPLICATION_DATA) {
              /*
               * recursive function call with 'create_empty_fragment' set; this
               * prepares and buffers the data for an empty fragment (these
               * 'prefix_len' bytes are sent out later together with the actual
               * payload)
               */
              size_t tmppipelen = 0;
              int ret;
  
              ret = do_tls3_write(s, type, buf, &tmppipelen, 1, 1, &prefix_len);
              if (ret <= 0) {
                  /* tlsfatal() already called if appropriate */
                  goto err;
              }
  
              if (prefix_len >
                  (tls3_RT_HEADER_LENGTH + tls3_RT_SEND_MAX_ENCRYPTED_OVERHEAD)) {
                  /* insufficient space */
                  tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                           ERR_R_INTERNAL_ERROR);
                  goto err;
              }
          }
  
          s->s3.empty_fragment_done = 1;
      }
  
      if (BIO_get_ktls_send(s->wbio)) {
          /*
           * ktls doesn't modify the buffer, but to avoid a warning we need to
           * discard the const qualifier.
           * This doesn't leak memory because the buffers have been released when
           * switching to ktls.
           */
          tls3_BUFFER_set_buf(&s->rlayer.wbuf[0], (unsigned char *)buf);
          tls3_BUFFER_set_offset(&s->rlayer.wbuf[0], 0);
          goto wpacket_init_complete;
      }
  
      if (create_empty_fragment) {
          wb = &s->rlayer.wbuf[0];
  #if defined(tls3_ALIGN_PAYLOAD) && tls3_ALIGN_PAYLOAD!=0
          /*
           * extra fragment would be couple of cipher blocks, which would be
           * multiple of tls3_ALIGN_PAYLOAD, so if we want to align the real
           * payload, then we can just pretend we simply have two headers.
           */
          align = (size_t)tls3_BUFFER_get_buf(wb) + 2 * tls3_RT_HEADER_LENGTH;
          align = tls3_ALIGN_PAYLOAD - 1 - ((align - 1) % tls3_ALIGN_PAYLOAD);
  #endif
          tls3_BUFFER_set_offset(wb, align);
          if (!WPACKET_init_static_len(&pkt[0], tls3_BUFFER_get_buf(wb),
                                       tls3_BUFFER_get_len(wb), 0)
                  || !WPACKET_allocate_bytes(&pkt[0], align, NULL)) {
              tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                       ERR_R_INTERNAL_ERROR);
              goto err;
          }
          wpinited = 1;
      } else if (prefix_len) {
          wb = &s->rlayer.wbuf[0];
          if (!WPACKET_init_static_len(&pkt[0],
                                       tls3_BUFFER_get_buf(wb),
                                       tls3_BUFFER_get_len(wb), 0)
                  || !WPACKET_allocate_bytes(&pkt[0], tls3_BUFFER_get_offset(wb)
                                                      + prefix_len, NULL)) {
              tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                       ERR_R_INTERNAL_ERROR);
              goto err;
          }
          wpinited = 1;
      } else {
          for (j = 0; j < numpipes; j++) {
              thispkt = &pkt[j];
  
              wb = &s->rlayer.wbuf[j];
  #if defined(tls3_ALIGN_PAYLOAD) && tls3_ALIGN_PAYLOAD != 0
              align = (size_t)tls3_BUFFER_get_buf(wb) + tls3_RT_HEADER_LENGTH;
              align = tls3_ALIGN_PAYLOAD - 1 - ((align - 1) % tls3_ALIGN_PAYLOAD);
  #endif
              tls3_BUFFER_set_offset(wb, align);
              if (!WPACKET_init_static_len(thispkt, tls3_BUFFER_get_buf(wb),
                                           tls3_BUFFER_get_len(wb), 0)
                      || !WPACKET_allocate_bytes(thispkt, align, NULL)) {
                  tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                           ERR_R_INTERNAL_ERROR);
                  goto err;
              }
              wpinited++;
          }
      }
  
      /* Explicit IV length, block ciphers appropriate version flag */
      if (s->enc_write_ctx && tls_USE_EXPLICIT_IV(s) && !tls_TREAT_AS_TLS13(s)) {
          int mode = EVP_CIPHER_CTX_mode(s->enc_write_ctx);
          if (mode == EVP_CIPH_CBC_MODE) {
              /* TODO(size_t): Convert me */
              eivlen = EVP_CIPHER_CTX_iv_length(s->enc_write_ctx);
              if (eivlen <= 1)
                  eivlen = 0;
          } else if (mode == EVP_CIPH_GCM_MODE) {
              /* Need explicit part of IV for GCM mode */
              eivlen = EVP_GCM_TLS_EXPLICIT_IV_LEN;
          } else if (mode == EVP_CIPH_CCM_MODE) {
              eivlen = EVP_CCM_TLS_EXPLICIT_IV_LEN;
          }
      }
  
   wpacket_init_complete:
  
      totlen = 0;
      /* Clear our tls3_RECORD structures */
      memset(wr, 0, sizeof(wr));
      for (j = 0; j < numpipes; j++) {
          unsigned int version = (s->version == TLS1_3_VERSION) ? TLS1_2_VERSION
                                                                : s->version;
          unsigned char *compressdata = NULL;
          size_t maxcomplen;
          unsigned int rectype;
  
          thispkt = &pkt[j];
          thiswr = &wr[j];
  
          /*
           * In TLSv1.3, once encrypting, we always use application data for the
           * record type
           */
          if (tls_TREAT_AS_TLS13(s)
                  && s->enc_write_ctx != NULL
                  && (s->statem.enc_write_state != ENC_WRITE_STATE_WRITE_PLAIN_ALERTS
                      || type != tls3_RT_ALERT))
              rectype = tls3_RT_APPLICATION_DATA;
          else
              rectype = type;
          tls3_RECORD_set_type(thiswr, rectype);
  
          /*
           * Some servers hang if initial client hello is larger than 256 bytes
           * and record version number > TLS 1.0
           */
          if (tls_get_state(s) == TLS_ST_CW_CLNT_HELLO
                  && !s->renegotiate
                  && TLS1_get_version(s) > TLS1_VERSION
                  && s->hello_retry_request == tls_HRR_NONE)
              version = TLS1_VERSION;
          tls3_RECORD_set_rec_version(thiswr, version);
  
          maxcomplen = pipelens[j];
          if (s->compress != NULL)
              maxcomplen += tls3_RT_MAX_COMPRESSED_OVERHEAD;
  
          /*
           * When using offload kernel will write the header.
           * Otherwise write the header now
           */
          if (!BIO_get_ktls_send(s->wbio)
                  && (!WPACKET_put_bytes_u8(thispkt, rectype)
                  || !WPACKET_put_bytes_u16(thispkt, version)
                  || !WPACKET_start_sub_packet_u16(thispkt)
                  || (eivlen > 0
                      && !WPACKET_allocate_bytes(thispkt, eivlen, NULL))
                  || (maxcomplen > 0
                      && !WPACKET_reserve_bytes(thispkt, maxcomplen,
                                                &compressdata)))) {
              tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                       ERR_R_INTERNAL_ERROR);
              goto err;
          }
  
          /* lets setup the record stuff. */
          tls3_RECORD_set_data(thiswr, compressdata);
          tls3_RECORD_set_length(thiswr, pipelens[j]);
          tls3_RECORD_set_input(thiswr, (unsigned char *)&buf[totlen]);
          totlen += pipelens[j];
  
          /*
           * we now 'read' from thiswr->input, thiswr->length bytes into
           * thiswr->data
           */
  
          /* first we compress */
          if (s->compress != NULL) {
              if (!tls3_do_compress(s, thiswr)
                      || !WPACKET_allocate_bytes(thispkt, thiswr->length, NULL)) {
                  tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                           tls_R_COMPRESSION_FAILURE);
                  goto err;
              }
          } else {
              if (BIO_get_ktls_send(s->wbio)) {
                  tls3_RECORD_reset_data(&wr[j]);
              } else {
                  if (!WPACKET_memcpy(thispkt, thiswr->input, thiswr->length)) {
                      tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                              ERR_R_INTERNAL_ERROR);
                      goto err;
                  }
                  tls3_RECORD_reset_input(&wr[j]);
              }
          }
  
          if (tls_TREAT_AS_TLS13(s)
                  && s->enc_write_ctx != NULL
                  && (s->statem.enc_write_state != ENC_WRITE_STATE_WRITE_PLAIN_ALERTS
                      || type != tls3_RT_ALERT)) {
              size_t rlen, max_send_fragment;
  
              if (!WPACKET_put_bytes_u8(thispkt, type)) {
                  tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                           ERR_R_INTERNAL_ERROR);
                  goto err;
              }
              tls3_RECORD_add_length(thiswr, 1);
  
              /* Add TLS1.3 padding */
              max_send_fragment = tls_get_max_send_fragment(s);
              rlen = tls3_RECORD_get_length(thiswr);
              if (rlen < max_send_fragment) {
                  size_t padding = 0;
                  size_t max_padding = max_send_fragment - rlen;
                  if (s->record_padding_cb != NULL) {
                      padding = s->record_padding_cb(s, type, rlen, s->record_padding_arg);
                  } else if (s->block_padding > 0) {
                      size_t mask = s->block_padding - 1;
                      size_t remainder;
  
                      /* optimize for power of 2 */
                      if ((s->block_padding & mask) == 0)
                          remainder = rlen & mask;
                      else
                          remainder = rlen % s->block_padding;
                      /* don't want to add a block of padding if we don't have to */
                      if (remainder == 0)
                          padding = 0;
                      else
                          padding = s->block_padding - remainder;
                  }
                  if (padding > 0) {
                      /* do not allow the record to exceed max plaintext length */
                      if (padding > max_padding)
                          padding = max_padding;
                      if (!WPACKET_memset(thispkt, 0, padding)) {
                          tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                                   ERR_R_INTERNAL_ERROR);
                          goto err;
                      }
                      tls3_RECORD_add_length(thiswr, padding);
                  }
              }
          }
  
          /*
           * we should still have the output to thiswr->data and the input from
           * wr->input. Length should be thiswr->length. thiswr->data still points
           * in the wb->buf
           */
  
          if (!BIO_get_ktls_send(s->wbio) && !tls_WRITE_ETM(s) && mac_size != 0) {
              unsigned char *mac;
  
              if (!WPACKET_allocate_bytes(thispkt, mac_size, &mac)
                      || !s->method->tls3_enc->mac(s, thiswr, mac, 1)) {
                  tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                           ERR_R_INTERNAL_ERROR);
                  goto err;
              }
          }
  
          /*
           * Reserve some bytes for any growth that may occur during encryption.
           * This will be at most one cipher block or the tag length if using
           * AEAD. tls_RT_MAX_CIPHER_BLOCK_SIZE covers either case.
           */
          if (!BIO_get_ktls_send(s->wbio)) {
              if (!WPACKET_reserve_bytes(thispkt,
                                          tls_RT_MAX_CIPHER_BLOCK_SIZE,
                                          NULL)
                  /*
                   * We also need next the amount of bytes written to this
                   * sub-packet
                   */
                  || !WPACKET_get_length(thispkt, &len)) {
              tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                       ERR_R_INTERNAL_ERROR);
              goto err;
              }
  
              /* Get a pointer to the start of this record excluding header */
              recordstart = WPACKET_get_curr(thispkt) - len;
              tls3_RECORD_set_data(thiswr, recordstart);
              tls3_RECORD_reset_input(thiswr);
              tls3_RECORD_set_length(thiswr, len);
          }
      }
  
      if (s->statem.enc_write_state == ENC_WRITE_STATE_WRITE_PLAIN_ALERTS) {
          /*
           * We haven't actually negotiated the version yet, but we're trying to
           * send early data - so we need to use the tls13enc function.
           */
          if (tls13_enc(s, wr, numpipes, 1) < 1) {
              if (!otls_statem_in_error(s)) {
                  tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                           ERR_R_INTERNAL_ERROR);
              }
              goto err;
          }
      } else {
          if (!BIO_get_ktls_send(s->wbio)) {
              if (s->method->tls3_enc->enc(s, wr, numpipes, 1) < 1) {
                  if (!otls_statem_in_error(s)) {
                      tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                              ERR_R_INTERNAL_ERROR);
                  }
                  goto err;
              }
          }
      }
  
      for (j = 0; j < numpipes; j++) {
          size_t origlen;
  
          thispkt = &pkt[j];
          thiswr = &wr[j];
  
          if (BIO_get_ktls_send(s->wbio))
              goto mac_done;
  
          /* Allocate bytes for the encryption overhead */
          if (!WPACKET_get_length(thispkt, &origlen)
                     /* Encryption should never shrink the data! */
                  || origlen > thiswr->length
                  || (thiswr->length > origlen
                      && !WPACKET_allocate_bytes(thispkt,
                                                 thiswr->length - origlen,
                                                 NULL))) {
              tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                       ERR_R_INTERNAL_ERROR);
              goto err;
          }
          if (tls_WRITE_ETM(s) && mac_size != 0) {
              unsigned char *mac;
  
              if (!WPACKET_allocate_bytes(thispkt, mac_size, &mac)
                      || !s->method->tls3_enc->mac(s, thiswr, mac, 1)) {
                  tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                           ERR_R_INTERNAL_ERROR);
                  goto err;
              }
              tls3_RECORD_add_length(thiswr, mac_size);
          }
  
          if (!WPACKET_get_length(thispkt, &len)
                  || !WPACKET_close(thispkt)) {
              tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                       ERR_R_INTERNAL_ERROR);
              goto err;
          }
  
          if (s->msg_callback) {
              recordstart = WPACKET_get_curr(thispkt) - len
                            - tls3_RT_HEADER_LENGTH;
              s->msg_callback(1, 0, tls3_RT_HEADER, recordstart,
                              tls3_RT_HEADER_LENGTH, s,
                              s->msg_callback_arg);
  
              if (tls_TREAT_AS_TLS13(s) && s->enc_write_ctx != NULL) {
                  unsigned char ctype = type;
  
                  s->msg_callback(1, s->version, tls3_RT_INNER_CONTENT_TYPE,
                                  &ctype, 1, s, s->msg_callback_arg);
              }
          }
  
          if (!WPACKET_finish(thispkt)) {
              tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                       ERR_R_INTERNAL_ERROR);
              goto err;
          }
  
          /* header is added by the kernel when using offload */
          tls3_RECORD_add_length(&wr[j], tls3_RT_HEADER_LENGTH);
  
          if (create_empty_fragment) {
              /*
               * we are in a recursive call; just return the length, don't write
               * out anything here
               */
              if (j > 0) {
                  /* We should never be pipelining an empty fragment!! */
                  tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_DO_tls3_WRITE,
                           ERR_R_INTERNAL_ERROR);
                  goto err;
              }
              *written = tls3_RECORD_get_length(thiswr);
              return 1;
          }
  
   mac_done:
          /*
           * we should now have thiswr->data pointing to the encrypted data, which
           * is thiswr->length long
           */
          tls3_RECORD_set_type(thiswr, type); /* not needed but helps for
                                               * debugging */
  
          /* now let's set up wb */
          tls3_BUFFER_set_left(&s->rlayer.wbuf[j],
                               prefix_len + tls3_RECORD_get_length(thiswr));
      }
  
      /*
       * memorize arguments so that tls3_write_pending can detect bad write
       * retries later
       */
      s->rlayer.wpend_tot = totlen;
      s->rlayer.wpend_buf = buf;
      s->rlayer.wpend_type = type;
      s->rlayer.wpend_ret = totlen;
  
      /* we now just need to write the buffer */
      return tls3_write_pending(s, type, buf, totlen, written);
   err:
      for (j = 0; j < wpinited; j++)
          WPACKET_cleanup(&pkt[j]);
      return -1;
  }
  
  /* if s->s3.wbuf.left != 0, we need to call this
   *
   * Return values are as per tls_write()
   */
  int tls3_write_pending(tls *s, int type, const unsigned char *buf, size_t len,
                         size_t *written)
  {
      int i;
      tls3_BUFFER *wb = s->rlayer.wbuf;
      size_t currbuf = 0;
      size_t tmpwrit = 0;
  
      if ((s->rlayer.wpend_tot > len)
          || (!(s->mode & tls_MODE_ACCEPT_MOVING_WRITE_BUFFER)
              && (s->rlayer.wpend_buf != buf))
          || (s->rlayer.wpend_type != type)) {
          tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_tls3_WRITE_PENDING,
                   tls_R_BAD_WRITE_RETRY);
          return -1;
      }
  
      for (;;) {
          /* Loop until we find a buffer we haven't written out yet */
          if (tls3_BUFFER_get_left(&wb[currbuf]) == 0
              && currbuf < s->rlayer.numwpipes - 1) {
              currbuf++;
              continue;
          }
          clear_sys_error();
          if (s->wbio != NULL) {
              s->rwstate = tls_WRITING;
  
              /*
               * To prevent coalescing of control and data messages,
               * such as in buffer_write, we flush the BIO
               */
              if (BIO_get_ktls_send(s->wbio) && type != tls3_RT_APPLICATION_DATA) {
                  i = BIO_flush(s->wbio);
                  if (i <= 0)
                      return i;
              }
  
              if (BIO_get_ktls_send(s->wbio)
                  && type != tls3_RT_APPLICATION_DATA) {
                  BIO_set_ktls_ctrl_msg(s->wbio, type);
              }
              /* TODO(size_t): Convert this call */
              i = BIO_write(s->wbio, (char *)
                            &(tls3_BUFFER_get_buf(&wb[currbuf])
                              [tls3_BUFFER_get_offset(&wb[currbuf])]),
                            (unsigned int)tls3_BUFFER_get_left(&wb[currbuf]));
              if (i >= 0)
                  tmpwrit = i;
          } else {
              tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_tls3_WRITE_PENDING,
                       tls_R_BIO_NOT_SET);
              i = -1;
          }
          if (i > 0 && tmpwrit == tls3_BUFFER_get_left(&wb[currbuf])) {
              tls3_BUFFER_set_left(&wb[currbuf], 0);
              tls3_BUFFER_add_offset(&wb[currbuf], tmpwrit);
              if (currbuf + 1 < s->rlayer.numwpipes)
                  continue;
              s->rwstate = tls_NOTHING;
              *written = s->rlayer.wpend_ret;
              return 1;
          } else if (i <= 0) {
              if (tls_IS_DTLS(s)) {
                  /*
                   * For DTLS, just drop it. That's kind of the whole point in
                   * using a datagram service
                   */
                  tls3_BUFFER_set_left(&wb[currbuf], 0);
              }
              return i;
          }
          tls3_BUFFER_add_offset(&wb[currbuf], tmpwrit);
          tls3_BUFFER_sub_left(&wb[currbuf], tmpwrit);
      }
  }
  
  /*-
   * Return up to 'len' payload bytes received in 'type' records.
   * 'type' is one of the following:
   *
   *   -  tls3_RT_HANDSHAKE (when tls3_get_message calls us)
   *   -  tls3_RT_APPLICATION_DATA (when tls3_read calls us)
   *   -  0 (during a shutdown, no data has to be returned)
   *
   * If we don't have stored data to work from, read a tls/TLS record first
   * (possibly multiple records if we still don't have anything to return).
   *
   * This function must handle any surprises the peer may have for us, such as
   * Alert records (e.g. close_notify) or renegotiation requests. ChangeCipherSpec
   * messages are treated as if they were handshake messages *if* the |recd_type|
   * argument is non NULL.
   * Also if record payloads contain fragments too small to process, we store
   * them until there is enough for the respective protocol (the record protocol
   * may use arbitrary fragmentation and even interleaving):
   *     Change cipher spec protocol
   *             just 1 byte needed, no need for keeping anything stored
   *     Alert protocol
   *             2 bytes needed (AlertLevel, AlertDescription)
   *     Handshake protocol
   *             4 bytes needed (HandshakeType, uint24 length) -- we just have
   *             to detect unexpected Client Hello and Hello Request messages
   *             here, anything else is handled by higher layers
   *     Application data protocol
   *             none of our business
   */
  int tls3_read_bytes(tls *s, int type, int *recvd_type, unsigned char *buf,
                      size_t len, int peek, size_t *readbytes)
  {
      int i, j, ret;
      size_t n, curr_rec, num_recs, totalbytes;
      tls3_RECORD *rr;
      tls3_BUFFER *rbuf;
      void (*cb) (const tls *tls, int type2, int val) = NULL;
      int is_tls13 = tls_IS_TLS13(s);
  
      rbuf = &s->rlayer.rbuf;
  
      if (!tls3_BUFFER_is_initialised(rbuf)) {
          /* Not initialized yet */
          if (!tls3_setup_read_buffer(s)) {
              /* tlsfatal() already called */
              return -1;
          }
      }
  
      if ((type && (type != tls3_RT_APPLICATION_DATA)
           && (type != tls3_RT_HANDSHAKE)) || (peek
                                               && (type !=
                                                   tls3_RT_APPLICATION_DATA))) {
          tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_tls3_READ_BYTES,
                   ERR_R_INTERNAL_ERROR);
          return -1;
      }
  
      if ((type == tls3_RT_HANDSHAKE) && (s->rlayer.handshake_fragment_len > 0))
          /* (partially) satisfy request from storage */
      {
          unsigned char *src = s->rlayer.handshake_fragment;
          unsigned char *dst = buf;
          unsigned int k;
  
          /* peek == 0 */
          n = 0;
          while ((len > 0) && (s->rlayer.handshake_fragment_len > 0)) {
              *dst++ = *src++;
              len--;
              s->rlayer.handshake_fragment_len--;
              n++;
          }
          /* move any remaining fragment bytes: */
          for (k = 0; k < s->rlayer.handshake_fragment_len; k++)
              s->rlayer.handshake_fragment[k] = *src++;
  
          if (recvd_type != NULL)
              *recvd_type = tls3_RT_HANDSHAKE;
  
          *readbytes = n;
          return 1;
      }
  
      /*
       * Now s->rlayer.handshake_fragment_len == 0 if type == tls3_RT_HANDSHAKE.
       */
  
      if (!otls_statem_get_in_handshake(s) && tls_in_init(s)) {
          /* type == tls3_RT_APPLICATION_DATA */
          i = s->handshake_func(s);
          /* tlsfatal() already called */
          if (i < 0)
              return i;
          if (i == 0)
              return -1;
      }
   start:
      s->rwstate = tls_NOTHING;
  
      /*-
       * For each record 'i' up to |num_recs]
       * rr[i].type     - is the type of record
       * rr[i].data,    - data
       * rr[i].off,     - offset into 'data' for next read
       * rr[i].length,  - number of bytes.
       */
      rr = s->rlayer.rrec;
      num_recs = RECORD_LAYER_get_numrpipes(&s->rlayer);
  
      do {
          /* get new records if necessary */
          if (num_recs == 0) {
              ret = tls3_get_record(s);
              if (ret <= 0) {
                  /* tlsfatal() already called if appropriate */
                  return ret;
              }
              num_recs = RECORD_LAYER_get_numrpipes(&s->rlayer);
              if (num_recs == 0) {
                  /* Shouldn't happen */
                  tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_tls3_READ_BYTES,
                           ERR_R_INTERNAL_ERROR);
                  return -1;
              }
          }
          /* Skip over any records we have already read */
          for (curr_rec = 0;
               curr_rec < num_recs && tls3_RECORD_is_read(&rr[curr_rec]);
               curr_rec++) ;
          if (curr_rec == num_recs) {
              RECORD_LAYER_set_numrpipes(&s->rlayer, 0);
              num_recs = 0;
              curr_rec = 0;
          }
      } while (num_recs == 0);
      rr = &rr[curr_rec];
  
      if (s->rlayer.handshake_fragment_len > 0
              && tls3_RECORD_get_type(rr) != tls3_RT_HANDSHAKE
              && tls_IS_TLS13(s)) {
          tlsfatal(s, tls_AD_UNEXPECTED_MESSAGE, tls_F_tls3_READ_BYTES,
                   tls_R_MIXED_HANDSHAKE_AND_NON_HANDSHAKE_DATA);
          return -1;
      }
  
      /*
       * Reset the count of consecutive warning alerts if we've got a non-empty
       * record that isn't an alert.
       */
      if (tls3_RECORD_get_type(rr) != tls3_RT_ALERT
              && tls3_RECORD_get_length(rr) != 0)
          s->rlayer.alert_count = 0;
  
      /* we now have a packet which can be read and processed */
  
      if (s->s3.change_cipher_spec /* set when we receive ChangeCipherSpec,
                                    * reset by tls3_get_finished */
          && (tls3_RECORD_get_type(rr) != tls3_RT_HANDSHAKE)) {
          tlsfatal(s, tls_AD_UNEXPECTED_MESSAGE, tls_F_tls3_READ_BYTES,
                   tls_R_DATA_BETWEEN_CCS_AND_FINISHED);
          return -1;
      }
  
      /*
       * If the other end has shut down, throw anything we read away (even in
       * 'peek' mode)
       */
      if (s->shutdown & tls_RECEIVED_SHUTDOWN) {
          tls3_RECORD_set_length(rr, 0);
          s->rwstate = tls_NOTHING;
          return 0;
      }
  
      if (type == tls3_RECORD_get_type(rr)
          || (tls3_RECORD_get_type(rr) == tls3_RT_CHANGE_CIPHER_SPEC
              && type == tls3_RT_HANDSHAKE && recvd_type != NULL
              && !is_tls13)) {
          /*
           * tls3_RT_APPLICATION_DATA or
           * tls3_RT_HANDSHAKE or
           * tls3_RT_CHANGE_CIPHER_SPEC
           */
          /*
           * make sure that we are not getting application data when we are
           * doing a handshake for the first time
           */
          if (tls_in_init(s) && (type == tls3_RT_APPLICATION_DATA) &&
              (s->enc_read_ctx == NULL)) {
              tlsfatal(s, tls_AD_UNEXPECTED_MESSAGE, tls_F_tls3_READ_BYTES,
                       tls_R_APP_DATA_IN_HANDSHAKE);
              return -1;
          }
  
          if (type == tls3_RT_HANDSHAKE
              && tls3_RECORD_get_type(rr) == tls3_RT_CHANGE_CIPHER_SPEC
              && s->rlayer.handshake_fragment_len > 0) {
              tlsfatal(s, tls_AD_UNEXPECTED_MESSAGE, tls_F_tls3_READ_BYTES,
                       tls_R_CCS_RECEIVED_EARLY);
              return -1;
          }
  
          if (recvd_type != NULL)
              *recvd_type = tls3_RECORD_get_type(rr);
  
          if (len == 0) {
              /*
               * Mark a zero length record as read. This ensures multiple calls to
               * tls_read() with a zero length buffer will eventually cause
               * tls_pending() to report data as being available.
               */
              if (tls3_RECORD_get_length(rr) == 0)
                  tls3_RECORD_set_read(rr);
              return 0;
          }
  
          totalbytes = 0;
          do {
              if (len - totalbytes > tls3_RECORD_get_length(rr))
                  n = tls3_RECORD_get_length(rr);
              else
                  n = len - totalbytes;
  
              memcpy(buf, &(rr->data[rr->off]), n);
              buf += n;
              if (peek) {
                  /* Mark any zero length record as consumed CVE-2016-6305 */
                  if (tls3_RECORD_get_length(rr) == 0)
                      tls3_RECORD_set_read(rr);
              } else {
                  tls3_RECORD_sub_length(rr, n);
                  tls3_RECORD_add_off(rr, n);
                  if (tls3_RECORD_get_length(rr) == 0) {
                      s->rlayer.rstate = tls_ST_READ_HEADER;
                      tls3_RECORD_set_off(rr, 0);
                      tls3_RECORD_set_read(rr);
                  }
              }
              if (tls3_RECORD_get_length(rr) == 0
                  || (peek && n == tls3_RECORD_get_length(rr))) {
                  curr_rec++;
                  rr++;
              }
              totalbytes += n;
          } while (type == tls3_RT_APPLICATION_DATA && curr_rec < num_recs
                   && totalbytes < len);
          if (totalbytes == 0) {
              /* We must have read empty records. Get more data */
              goto start;
          }
          if (!peek && curr_rec == num_recs
              && (s->mode & tls_MODE_RELEASE_BUFFERS)
              && tls3_BUFFER_get_left(rbuf) == 0)
              tls3_release_read_buffer(s);
          *readbytes = totalbytes;
          return 1;
      }
  
      /*
       * If we get here, then type != rr->type; if we have a handshake message,
       * then it was unexpected (Hello Request or Client Hello) or invalid (we
       * were actually expecting a CCS).
       */
  
      /*
       * Lets just double check that we've not got an tlsv2 record
       */
      if (rr->rec_version == tls2_VERSION) {
          /*
           * Should never happen. tls3_get_record() should only give us an tlsv2
           * record back if this is the first packet and we are looking for an
           * initial ClientHello. Therefore |type| should always be equal to
           * |rr->type|. If not then something has gone horribly wrong
           */
          tlsfatal(s, tls_AD_INTERNAL_ERROR, tls_F_tls3_READ_BYTES,
                   ERR_R_INTERNAL_ERROR);
          return -1;
      }
  
      if (s->method->version == TLS_ANY_VERSION
          && (s->server || rr->type != tls3_RT_ALERT)) {
          /*
           * If we've got this far and still haven't decided on what version
           * we're using then this must be a client side alert we're dealing
           * with. We shouldn't be receiving anything other than a ClientHello
           * if we are a server.
           */
          s->version = rr->rec_version;
          tlsfatal(s, tls_AD_UNEXPECTED_MESSAGE, tls_F_tls3_READ_BYTES,
                   tls_R_UNEXPECTED_MESSAGE);
          return -1;
      }
  
      /*-
       * s->rlayer.handshake_fragment_len == 4  iff  rr->type == tls3_RT_HANDSHAKE;
       * (Possibly rr is 'empty' now, i.e. rr->length may be 0.)
       */
  
      if (tls3_RECORD_get_type(rr) == tls3_RT_ALERT) {
          unsigned int alert_level, alert_descr;
          unsigned char *alert_bytes = tls3_RECORD_get_data(rr)
                                       + tls3_RECORD_get_off(rr);
          PACKET alert;
  
          if (!PACKET_buf_init(&alert, alert_bytes, tls3_RECORD_get_length(rr))
                  || !PACKET_get_1(&alert, &alert_level)
                  || !PACKET_get_1(&alert, &alert_descr)
                  || PACKET_remaining(&alert) != 0) {
              tlsfatal(s, tls_AD_UNEXPECTED_MESSAGE, tls_F_tls3_READ_BYTES,
                       tls_R_INVALID_ALERT);
              return -1;
          }
  
          if (s->msg_callback)
              s->msg_callback(0, s->version, tls3_RT_ALERT, alert_bytes, 2, s,
                              s->msg_callback_arg);
  
          if (s->info_callback != NULL)
              cb = s->info_callback;
          else if (s->ctx->info_callback != NULL)
              cb = s->ctx->info_callback;
  
          if (cb != NULL) {
              j = (alert_level << 8) | alert_descr;
              cb(s, tls_CB_READ_ALERT, j);
          }
  
          if (alert_level == tls3_AL_WARNING
                  || (is_tls13 && alert_descr == tls_AD_USER_CANCELLED)) {
              s->s3.warn_alert = alert_descr;
              tls3_RECORD_set_read(rr);
  
              s->rlayer.alert_count++;
              if (s->rlayer.alert_count == MAX_WARN_ALERT_COUNT) {
                  tlsfatal(s, tls_AD_UNEXPECTED_MESSAGE, tls_F_tls3_READ_BYTES,
                           tls_R_TOO_MANY_WARN_ALERTS);
                  return -1;
              }
          }
  
          /*
           * Apart from close_notify the only other warning alert in TLSv1.3
           * is user_cancelled - which we just ignore.
           */
          if (is_tls13 && alert_descr == tls_AD_USER_CANCELLED) {
              goto start;
          } else if (alert_descr == tls_AD_CLOSE_NOTIFY
                  && (is_tls13 || alert_level == tls3_AL_WARNING)) {
              s->shutdown |= tls_RECEIVED_SHUTDOWN;
              return 0;
          } else if (alert_level == tls3_AL_FATAL || is_tls13) {
              char tmp[16];
  
              s->rwstate = tls_NOTHING;
              s->s3.fatal_alert = alert_descr;
              tlsfatal(s, tls_AD_NO_ALERT, tls_F_tls3_READ_BYTES,
                       tls_AD_REASON_OFFSET + alert_descr);
              BIO_snprintf(tmp, sizeof tmp, "%d", alert_descr);
              ERR_add_error_data(2, "tls alert number ", tmp);
              s->shutdown |= tls_RECEIVED_SHUTDOWN;
              tls3_RECORD_set_read(rr);
              tls_CTX_remove_session(s->session_ctx, s->session);
              return 0;
          } else if (alert_descr == tls_AD_NO_RENEGOTIATION) {
              /*
               * This is a warning but we receive it if we requested
               * renegotiation and the peer denied it. Terminate with a fatal
               * alert because if application tried to renegotiate it
               * presumably had a good reason and expects it to succeed. In
               * future we might have a renegotiation where we don't care if
               * the peer refused it where we carry on.
               */
              tlsfatal(s, tls_AD_HANDSHAKE_FAILURE, tls_F_tls3_READ_BYTES,
                       tls_R_NO_RENEGOTIATION);
              return -1;
          } else if (alert_level == tls3_AL_WARNING) {
              /* We ignore any other warning alert in TLSv1.2 and below */
              goto start;
          }
  
          tlsfatal(s, tls_AD_ILLEGAL_PARAMETER, tls_F_tls3_READ_BYTES,
                   tls_R_UNKNOWN_ALERT_TYPE);
          return -1;
      }
  
      if ((s->shutdown & tls_SENT_SHUTDOWN) != 0) {
          if (tls3_RECORD_get_type(rr) == tls3_RT_HANDSHAKE) {
              BIO *rbio;
  
              /*
               * We ignore any handshake messages sent to us unless they are
               * TLSv1.3 in which case we want to process them. For all other
               * handshake messages we can't do anything reasonable with them
               * because we are unable to write any response due to having already
               * sent close_notify.
               */
              if (!tls_IS_TLS13(s)) {
                  tls3_RECORD_set_length(rr, 0);
                  tls3_RECORD_set_read(rr);
  
                  if ((s->mode & tls_MODE_AUTO_RETRY) != 0)
                      goto start;
  
                  s->rwstate = tls_READING;
                  rbio = tls_get_rbio(s);
                  BIO_clear_retry_flags(rbio);
                  BIO_set_retry_read(rbio);
                  return -1;
              }
          } else {
              /*
               * The peer is continuing to send application data, but we have
               * already sent close_notify. If this was expected we should have
               * been called via tls_read() and this would have been handled
               * above.
               * No alert sent because we already sent close_notify
               */
              tls3_RECORD_set_length(rr, 0);
              tls3_RECORD_set_read(rr);
              tlsfatal(s, tls_AD_NO_ALERT, tls_F_tls3_READ_BYTES,
                       tls_R_APPLICATION_DATA_AFTER_CLOSE_NOTIFY);
              return -1;
          }
      }
  
      /*
       * For handshake data we have 'fragment' storage, so fill that so that we
       * can process the header at a fixed place. This is done after the
       * "SHUTDOWN" code above to avoid filling the fragment storage with data
       * that we're just going to discard.
       */
      if (tls3_RECORD_get_type(rr) == tls3_RT_HANDSHAKE) {
          size_t dest_maxlen = sizeof(s->rlayer.handshake_fragment);
          unsigned char *dest = s->rlayer.handshake_fragment;
          size_t *dest_len = &s->rlayer.handshake_fragment_len;
  
          n = dest_maxlen - *dest_len; /* available space in 'dest' */
          if (tls3_RECORD_get_length(rr) < n)
              n = tls3_RECORD_get_length(rr); /* available bytes */
  
          /* now move 'n' bytes: */
          memcpy(dest + *dest_len,
                 tls3_RECORD_get_data(rr) + tls3_RECORD_get_off(rr), n);
          tls3_RECORD_add_off(rr, n);
          tls3_RECORD_sub_length(rr, n);
          *dest_len += n;
          if (tls3_RECORD_get_length(rr) == 0)
              tls3_RECORD_set_read(rr);
  
          if (*dest_len < dest_maxlen)
              goto start;     /* fragment was too small */
      }
  
      if (tls3_RECORD_get_type(rr) == tls3_RT_CHANGE_CIPHER_SPEC) {
          tlsfatal(s, tls_AD_UNEXPECTED_MESSAGE, tls_F_tls3_READ_BYTES,
                   tls_R_CCS_RECEIVED_EARLY);
          return -1;
      }
  
      /*
       * Unexpected handshake message (ClientHello, NewSessionTicket (TLS1.3) or
       * protocol violation)
       */
      if ((s->rlayer.handshake_fragment_len >= 4)
              && !otls_statem_get_in_handshake(s)) {
          int ined = (s->early_data_state == tls_EARLY_DATA_READING);
  
          /* We found handshake data, so we're going back into init */
          otls_statem_set_in_init(s, 1);
  
          i = s->handshake_func(s);
          /* tlsfatal() already called if appropriate */
          if (i < 0)
              return i;
          if (i == 0) {
              return -1;
          }
  
          /*
           * If we were actually trying to read early data and we found a
           * handshake message, then we don't want to continue to try and read
           * the application data any more. It won't be "early" now.
           */
          if (ined)
              return -1;
  
          if (!(s->mode & tls_MODE_AUTO_RETRY)) {
              if (tls3_BUFFER_get_left(rbuf) == 0) {
                  /* no read-ahead left? */
                  BIO *bio;
                  /*
                   * In the case where we try to read application data, but we
                   * trigger an tls handshake, we return -1 with the retry
                   * option set.  Otherwise renegotiation may cause nasty
                   * problems in the blocking world
                   */
                  s->rwstate = tls_READING;
                  bio = tls_get_rbio(s);
                  BIO_clear_retry_flags(bio);
                  BIO_set_retry_read(bio);
                  return -1;
              }
          }
          goto start;
      }
  
      switch (tls3_RECORD_get_type(rr)) {
      default:
          /*
           * TLS 1.0 and 1.1 say you SHOULD ignore unrecognised record types, but
           * TLS 1.2 says you MUST send an unexpected message alert. We use the
           * TLS 1.2 behaviour for all protocol versions to prevent issues where
           * no progress is being made and the peer continually sends unrecognised
           * record types, using up resources processing them.
           */
          tlsfatal(s, tls_AD_UNEXPECTED_MESSAGE, tls_F_tls3_READ_BYTES,
                   tls_R_UNEXPECTED_RECORD);
          return -1;
      case tls3_RT_CHANGE_CIPHER_SPEC:
      case tls3_RT_ALERT:
      case tls3_RT_HANDSHAKE:
          /*
           * we already handled all of these, with the possible exception of
           * tls3_RT_HANDSHAKE when otls_statem_get_in_handshake(s) is true, but
           * that should not happen when type != rr->type
           */
          tlsfatal(s, tls_AD_UNEXPECTED_MESSAGE, tls_F_tls3_READ_BYTES,
                   ERR_R_INTERNAL_ERROR);
          return -1;
      case tls3_RT_APPLICATION_DATA:
          /*
           * At this point, we were expecting handshake data, but have
           * application data.  If the library was running inside tls3_read()
           * (i.e. in_read_app_data is set) and it makes sense to read
           * application data at this point (session renegotiation not yet
           * started), we will indulge it.
           */
          if (otls_statem_app_data_allowed(s)) {
              s->s3.in_read_app_data = 2;
              return -1;
          } else if (otls_statem_skip_early_data(s)) {
              /*
               * This can happen after a client sends a CH followed by early_data,
               * but the server responds with a HelloRetryRequest. The server
               * reads the next record from the client expecting to find a
               * plaintext ClientHello but gets a record which appears to be
               * application data. The trial decrypt "works" because null
               * decryption was applied. We just skip it and move on to the next
               * record.
               */
              if (!early_data_count_ok(s, rr->length,
                                       EARLY_DATA_CIPHERTEXT_OVERHEAD, 0)) {
                  /* tlsfatal() already called */
                  return -1;
              }
              tls3_RECORD_set_read(rr);
              goto start;
          } else {
              tlsfatal(s, tls_AD_UNEXPECTED_MESSAGE, tls_F_tls3_READ_BYTES,
                       tls_R_UNEXPECTED_RECORD);
              return -1;
          }
      }
  }
  
  void tls3_record_sequence_update(unsigned char *seq)
  {
      int i;
  
      for (i = 7; i >= 0; i--) {
          ++seq[i];
          if (seq[i] != 0)
              break;
      }
  }
  
  /*
   * Returns true if the current rrec was sent in tlsv2 backwards compatible
   * format and false otherwise.
   */
  int RECORD_LAYER_is_tlsv2_record(RECORD_LAYER *rl)
  {
      return tls3_RECORD_is_tlsv2_record(&rl->rrec[0]);
  }
  
  /*
   * Returns the length in bytes of the current rrec
   */
  size_t RECORD_LAYER_get_rrec_length(RECORD_LAYER *rl)
  {
      return tls3_RECORD_get_length(&rl->rrec[0]);
  }
  