text: /*
   * nghttp2 - HTTP/2 C Library
   *
   * Copyright (c) 2013 Tatsuhiro Tsujikawa
   *
   * Permission is hereby granted, free of charge, to any person obtaining
   * a copy of this software and associated documentation files (the
   * "Software"), to deal in the Software without restriction, including
   * without limitation the rights to use, copy, modify, merge, publish,
   * distribute, sublicense, and/or sell copies of the Software, and to
   * permit persons to whom the Software is furnished to do so, subject to
   * the following conditions:
   *
   * The above copyright notice and this permission notice shall be
   * included in all copies or substantial portions of the Software.
   *
   * 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 "nghttp2_frame.h"
  
  #include <string.h>
  #include <assert.h>
  #include <stdio.h>
  #include <errno.h>
  
  #include "nghttp2_helper.h"
  #include "nghttp2_net.h"
  #include "nghttp2_priority_spec.h"
  
  void nghttp2_frame_pack_frame_hd(uint8_t *buf, const nghttp2_frame_hd *hd) {
    nghttp2_put_uint32be(&buf[0], (uint32_t)(hd->length << 8));
    buf[3] = hd->type;
    buf[4] = hd->flags;
    nghttp2_put_uint32be(&buf[5], hd->stream_id);
    /* ignore hd->reserved for now */
  }
  
  void nghttp2_frame_unpack_frame_hd(nghttp2_frame_hd *hd, const uint8_t *buf) {
    hd->length = nghttp2_get_uint32(&buf[0]) >> 8;
    hd->type = buf[3];
    hd->flags = buf[4];
    hd->stream_id = nghttp2_get_uint32(&buf[5]) & NGHTTP2_STREAM_ID_MASK;
    hd->reserved = 0;
  }
  
  void nghttp2_frame_hd_init(nghttp2_frame_hd *hd, size_t length, uint8_t type,
                             uint8_t flags, int32_t stream_id) {
    hd->length = length;
    hd->type = type;
    hd->flags = flags;
    hd->stream_id = stream_id;
    hd->reserved = 0;
  }
  
  void nghttp2_frame_headers_init(nghttp2_headers *frame, uint8_t flags,
                                  int32_t stream_id, nghttp2_headers_category cat,
                                  const nghttp2_priority_spec *pri_spec,
                                  nghttp2_nv *nva, size_t nvlen) {
    nghttp2_frame_hd_init(&frame->hd, 0, NGHTTP2_HEADERS, flags, stream_id);
    frame->padlen = 0;
    frame->nva = nva;
    frame->nvlen = nvlen;
    frame->cat = cat;
  
    if (pri_spec) {
      frame->pri_spec = *pri_spec;
    } else {
      nghttp2_priority_spec_default_init(&frame->pri_spec);
    }
  }
  
  void nghttp2_frame_headers_free(nghttp2_headers *frame, nghttp2_mem *mem) {
    nghttp2_nv_array_del(frame->nva, mem);
  }
  
  void nghttp2_frame_priority_init(nghttp2_priority *frame, int32_t stream_id,
                                   const nghttp2_priority_spec *pri_spec) {
    nghttp2_frame_hd_init(&frame->hd, NGHTTP2_PRIORITY_SPECLEN, NGHTTP2_PRIORITY,
                          NGHTTP2_FLAG_NONE, stream_id);
    frame->pri_spec = *pri_spec;
  }
  
  void nghttp2_frame_priority_free(nghttp2_priority *frame _U_) {}
  
  void nghttp2_frame_rst_stream_init(nghttp2_rst_stream *frame, int32_t stream_id,
                                     uint32_t error_code) {
    nghttp2_frame_hd_init(&frame->hd, 4, NGHTTP2_RST_STREAM, NGHTTP2_FLAG_NONE,
                          stream_id);
    frame->error_code = error_code;
  }
  
  void nghttp2_frame_rst_stream_free(nghttp2_rst_stream *frame _U_) {}
  
  void nghttp2_frame_settings_init(nghttp2_settings *frame, uint8_t flags,
                                   nghttp2_settings_entry *iv, size_t niv) {
    nghttp2_frame_hd_init(&frame->hd, niv * NGHTTP2_FRAME_SETTINGS_ENTRY_LENGTH,
                          NGHTTP2_SETTINGS, flags, 0);
    frame->niv = niv;
    frame->iv = iv;
  }
  
  void nghttp2_frame_settings_free(nghttp2_settings *frame, nghttp2_mem *mem) {
    nghttp2_mem_free(mem, frame->iv);
  }
  
  void nghttp2_frame_push_promise_init(nghttp2_push_promise *frame, uint8_t flags,
                                       int32_t stream_id,
                                       int32_t promised_stream_id,
                                       nghttp2_nv *nva, size_t nvlen) {
    nghttp2_frame_hd_init(&frame->hd, 0, NGHTTP2_PUSH_PROMISE, flags, stream_id);
    frame->padlen = 0;
    frame->nva = nva;
    frame->nvlen = nvlen;
    frame->promised_stream_id = promised_stream_id;
    frame->reserved = 0;
  }
  
  void nghttp2_frame_push_promise_free(nghttp2_push_promise *frame,
                                       nghttp2_mem *mem) {
    nghttp2_nv_array_del(frame->nva, mem);
  }
  
  void nghttp2_frame_ping_init(nghttp2_ping *frame, uint8_t flags,
                               const uint8_t *opaque_data) {
    nghttp2_frame_hd_init(&frame->hd, 8, NGHTTP2_PING, flags, 0);
    if (opaque_data) {
      memcpy(frame->opaque_data, opaque_data, sizeof(frame->opaque_data));
    } else {
      memset(frame->opaque_data, 0, sizeof(frame->opaque_data));
    }
  }
  
  void nghttp2_frame_ping_free(nghttp2_ping *frame _U_) {}
  
  void nghttp2_frame_goaway_init(nghttp2_goaway *frame, int32_t last_stream_id,
                                 uint32_t error_code, uint8_t *opaque_data,
                                 size_t opaque_data_len) {
    nghttp2_frame_hd_init(&frame->hd, 8 + opaque_data_len, NGHTTP2_GOAWAY,
                          NGHTTP2_FLAG_NONE, 0);
    frame->last_stream_id = last_stream_id;
    frame->error_code = error_code;
    frame->opaque_data = opaque_data;
    frame->opaque_data_len = opaque_data_len;
    frame->reserved = 0;
  }
  
  void nghttp2_frame_goaway_free(nghttp2_goaway *frame, nghttp2_mem *mem) {
    nghttp2_mem_free(mem, frame->opaque_data);
  }
  
  void nghttp2_frame_window_update_init(nghttp2_window_update *frame,
                                        uint8_t flags, int32_t stream_id,
                                        int32_t window_size_increment) {
    nghttp2_frame_hd_init(&frame->hd, 4, NGHTTP2_WINDOW_UPDATE, flags, stream_id);
    frame->window_size_increment = window_size_increment;
    frame->reserved = 0;
  }
  
  void nghttp2_frame_window_update_free(nghttp2_window_update *frame _U_) {}
  
  size_t nghttp2_frame_trail_padlen(nghttp2_frame *frame, size_t padlen) {
    return padlen - ((frame->hd.flags & NGHTTP2_FLAG_PADDED) > 0);
  }
  
  void nghttp2_frame_data_init(nghttp2_data *frame, uint8_t flags,
                               int32_t stream_id) {
    /* At this moment, the length of DATA frame is unknown */
    nghttp2_frame_hd_init(&frame->hd, 0, NGHTTP2_DATA, flags, stream_id);
    frame->padlen = 0;
  }
  
  void nghttp2_frame_data_free(nghttp2_data *frame _U_) {}
  
  size_t nghttp2_frame_priority_len(uint8_t flags) {
    if (flags & NGHTTP2_FLAG_PRIORITY) {
      return NGHTTP2_PRIORITY_SPECLEN;
    }
  
    return 0;
  }
  
  size_t nghttp2_frame_headers_payload_nv_offset(nghttp2_headers *frame) {
    return nghttp2_frame_priority_len(frame->hd.flags);
  }
  
  /*
   * Call this function after payload was serialized, but not before
   * changing buf->pos and serializing frame header.
   *
   * This function assumes bufs->cur points to the last buf chain of the
   * frame(s).
   *
   * This function serializes frame header for HEADERS/PUSH_PROMISE and
   * handles their successive CONTINUATION frames.
   *
   * We don't process any padding here.
   */
  static int frame_pack_headers_shared(nghttp2_bufs *bufs,
                                       nghttp2_frame_hd *frame_hd) {
    nghttp2_buf *buf;
    nghttp2_buf_chain *ci, *ce;
    nghttp2_frame_hd hd;
  
    buf = &bufs->head->buf;
  
    hd = *frame_hd;
    hd.length = nghttp2_buf_len(buf);
  
    DEBUGF(fprintf(stderr, "send: HEADERS/PUSH_PROMISE, payloadlen=%zu\n",
                   hd.length));
  
    /* We have multiple frame buffers, which means one or more
       CONTINUATION frame is involved. Remove END_HEADERS flag from the
       first frame. */
    if (bufs->head != bufs->cur) {
      hd.flags &= ~NGHTTP2_FLAG_END_HEADERS;
    }
  
    buf->pos -= NGHTTP2_FRAME_HDLEN;
    nghttp2_frame_pack_frame_hd(buf->pos, &hd);
  
    if (bufs->head != bufs->cur) {
      /* 2nd and later frames are CONTINUATION frames. */
      hd.type = NGHTTP2_CONTINUATION;
      /* We don't have no flags except for last CONTINUATION */
      hd.flags = NGHTTP2_FLAG_NONE;
  
      ce = bufs->cur;
  
      for (ci = bufs->head->next; ci != ce; ci = ci->next) {
        buf = &ci->buf;
  
        hd.length = nghttp2_buf_len(buf);
  
        DEBUGF(fprintf(stderr, "send: int CONTINUATION, payloadlen=%zu\n",
                       hd.length));
  
        buf->pos -= NGHTTP2_FRAME_HDLEN;
        nghttp2_frame_pack_frame_hd(buf->pos, &hd);
      }
  
      buf = &ci->buf;
      hd.length = nghttp2_buf_len(buf);
      /* Set END_HEADERS flag for last CONTINUATION */
      hd.flags = NGHTTP2_FLAG_END_HEADERS;
  
      DEBUGF(fprintf(stderr, "send: last CONTINUATION, payloadlen=%zu\n",
                     hd.length));
  
      buf->pos -= NGHTTP2_FRAME_HDLEN;
      nghttp2_frame_pack_frame_hd(buf->pos, &hd);
    }
  
    return 0;
  }
  
  int nghttp2_frame_pack_headers(nghttp2_bufs *bufs, nghttp2_headers *frame,
                                 nghttp2_hd_deflater *deflater) {
    size_t nv_offset;
    int rv;
    nghttp2_buf *buf;
  
    assert(bufs->head == bufs->cur);
  
    nv_offset = nghttp2_frame_headers_payload_nv_offset(frame);
  
    buf = &bufs->cur->buf;
  
    buf->pos += nv_offset;
    buf->last = buf->pos;
  
    /* This call will adjust buf->last to the correct position */
    rv = nghttp2_hd_deflate_hd_bufs(deflater, bufs, frame->nva, frame->nvlen);
  
    if (rv == NGHTTP2_ERR_BUFFER_ERROR) {
      rv = NGHTTP2_ERR_HEADER_COMP;
    }
  
    buf->pos -= nv_offset;
  
    if (rv != 0) {
      return rv;
    }
  
    if (frame->hd.flags & NGHTTP2_FLAG_PRIORITY) {
      nghttp2_frame_pack_priority_spec(buf->pos, &frame->pri_spec);
    }
  
    frame->padlen = 0;
    frame->hd.length = nghttp2_bufs_len(bufs);
  
    return frame_pack_headers_shared(bufs, &frame->hd);
  }
  
  void nghttp2_frame_pack_priority_spec(uint8_t *buf,
                                        const nghttp2_priority_spec *pri_spec) {
    nghttp2_put_uint32be(buf, pri_spec->stream_id);
    if (pri_spec->exclusive) {
      buf[0] |= 0x80;
    }
    buf[4] = pri_spec->weight - 1;
  }
  
  void nghttp2_frame_unpack_priority_spec(nghttp2_priority_spec *pri_spec,
                                          uint8_t flags _U_,
                                          const uint8_t *payload,
                                          size_t payloadlen _U_) {
    int32_t dep_stream_id;
    uint8_t exclusive;
    int32_t weight;
  
    dep_stream_id = nghttp2_get_uint32(payload) & NGHTTP2_STREAM_ID_MASK;
    exclusive = (payload[0] & 0x80) > 0;
    weight = payload[4] + 1;
  
    nghttp2_priority_spec_init(pri_spec, dep_stream_id, weight, exclusive);
  }
  
  int nghttp2_frame_unpack_headers_payload(nghttp2_headers *frame,
                                           const uint8_t *payload,
                                           size_t payloadlen) {
    if (frame->hd.flags & NGHTTP2_FLAG_PRIORITY) {
      nghttp2_frame_unpack_priority_spec(&frame->pri_spec, frame->hd.flags,
                                         payload, payloadlen);
    } else {
      nghttp2_priority_spec_default_init(&frame->pri_spec);
    }
  
    frame->nva = NULL;
    frame->nvlen = 0;
  
    return 0;
  }
  
  int nghttp2_frame_pack_priority(nghttp2_bufs *bufs, nghttp2_priority *frame) {
    nghttp2_buf *buf;
  
    assert(bufs->head == bufs->cur);
  
    buf = &bufs->head->buf;
  
    assert(nghttp2_buf_avail(buf) >= NGHTTP2_PRIORITY_SPECLEN);
  
    buf->pos -= NGHTTP2_FRAME_HDLEN;
  
    nghttp2_frame_pack_frame_hd(buf->pos, &frame->hd);
  
    nghttp2_frame_pack_priority_spec(buf->last, &frame->pri_spec);
  
    buf->last += NGHTTP2_PRIORITY_SPECLEN;
  
    return 0;
  }
  
  void nghttp2_frame_unpack_priority_payload(nghttp2_priority *frame,
                                             const uint8_t *payload,
                                             size_t payloadlen) {
    nghttp2_frame_unpack_priority_spec(&frame->pri_spec, frame->hd.flags, payload,
                                       payloadlen);
  }
  
  int nghttp2_frame_pack_rst_stream(nghttp2_bufs *bufs,
                                    nghttp2_rst_stream *frame) {
    nghttp2_buf *buf;
  
    assert(bufs->head == bufs->cur);
  
    buf = &bufs->head->buf;
  
    assert(nghttp2_buf_avail(buf) >= 4);
  
    buf->pos -= NGHTTP2_FRAME_HDLEN;
  
    nghttp2_frame_pack_frame_hd(buf->pos, &frame->hd);
  
    nghttp2_put_uint32be(buf->last, frame->error_code);
    buf->last += 4;
  
    return 0;
  }
  
  void nghttp2_frame_unpack_rst_stream_payload(nghttp2_rst_stream *frame,
                                               const uint8_t *payload,
                                               size_t payloadlen _U_) {
    frame->error_code = nghttp2_get_uint32(payload);
  }
  
  int nghttp2_frame_pack_settings(nghttp2_bufs *bufs, nghttp2_settings *frame) {
    nghttp2_buf *buf;
  
    assert(bufs->head == bufs->cur);
  
    buf = &bufs->head->buf;
  
    if (nghttp2_buf_avail(buf) < (ssize_t)frame->hd.length) {
      return NGHTTP2_ERR_FRAME_SIZE_ERROR;
    }
  
    buf->pos -= NGHTTP2_FRAME_HDLEN;
  
    nghttp2_frame_pack_frame_hd(buf->pos, &frame->hd);
  
    buf->last +=
        nghttp2_frame_pack_settings_payload(buf->last, frame->iv, frame->niv);
  
    return 0;
  }
  
  size_t nghttp2_frame_pack_settings_payload(uint8_t *buf,
                                             const nghttp2_settings_entry *iv,
                                             size_t niv) {
    size_t i;
    for (i = 0; i < niv; ++i, buf += NGHTTP2_FRAME_SETTINGS_ENTRY_LENGTH) {
      nghttp2_put_uint16be(buf, iv[i].settings_id);
      nghttp2_put_uint32be(buf + 2, iv[i].value);
    }
    return NGHTTP2_FRAME_SETTINGS_ENTRY_LENGTH * niv;
  }
  
  int nghttp2_frame_unpack_settings_payload(nghttp2_settings *frame,
                                            nghttp2_settings_entry *iv,
                                            size_t niv, nghttp2_mem *mem) {
    size_t payloadlen = niv * sizeof(nghttp2_settings_entry);
  
    if (niv == 0) {
      frame->iv = NULL;
    } else {
      frame->iv = nghttp2_mem_malloc(mem, payloadlen);
  
      if (frame->iv == NULL) {
        return NGHTTP2_ERR_NOMEM;
      }
  
      memcpy(frame->iv, iv, payloadlen);
    }
  
    frame->niv = niv;
    return 0;
  }
  
  void nghttp2_frame_unpack_settings_entry(nghttp2_settings_entry *iv,
                                           const uint8_t *payload) {
    iv->settings_id = nghttp2_get_uint16(&payload[0]);
    iv->value = nghttp2_get_uint32(&payload[2]);
  }
  
  int nghttp2_frame_unpack_settings_payload2(nghttp2_settings_entry **iv_ptr,
                                             size_t *niv_ptr,
                                             const uint8_t *payload,
                                             size_t payloadlen,
                                             nghttp2_mem *mem) {
    size_t i;
  
    *niv_ptr = payloadlen / NGHTTP2_FRAME_SETTINGS_ENTRY_LENGTH;
  
    if (*niv_ptr == 0) {
      *iv_ptr = NULL;
  
      return 0;
    }
  
    *iv_ptr =
        nghttp2_mem_malloc(mem, (*niv_ptr) * sizeof(nghttp2_settings_entry));
  
    if (*iv_ptr == NULL) {
      return NGHTTP2_ERR_NOMEM;
    }
  
    for (i = 0; i < *niv_ptr; ++i) {
      size_t off = i * NGHTTP2_FRAME_SETTINGS_ENTRY_LENGTH;
      nghttp2_frame_unpack_settings_entry(&(*iv_ptr)[i], &payload[off]);
    }
  
    return 0;
  }
  
  int nghttp2_frame_pack_push_promise(nghttp2_bufs *bufs,
                                      nghttp2_push_promise *frame,
                                      nghttp2_hd_deflater *deflater) {
    size_t nv_offset = 4;
    int rv;
    nghttp2_buf *buf;
  
    assert(bufs->head == bufs->cur);
  
    buf = &bufs->cur->buf;
  
    buf->pos += nv_offset;
    buf->last = buf->pos;
  
    /* This call will adjust buf->last to the correct position */
    rv = nghttp2_hd_deflate_hd_bufs(deflater, bufs, frame->nva, frame->nvlen);
  
    if (rv == NGHTTP2_ERR_BUFFER_ERROR) {
      rv = NGHTTP2_ERR_HEADER_COMP;
    }
  
    buf->pos -= nv_offset;
  
    if (rv != 0) {
      return rv;
    }
  
    nghttp2_put_uint32be(buf->pos, frame->promised_stream_id);
  
    frame->padlen = 0;
    frame->hd.length = nghttp2_bufs_len(bufs);
  
    return frame_pack_headers_shared(bufs, &frame->hd);
  }
  
  int nghttp2_frame_unpack_push_promise_payload(nghttp2_push_promise *frame,
                                                const uint8_t *payload,
                                                size_t payloadlen _U_) {
    frame->promised_stream_id =
        nghttp2_get_uint32(payload) & NGHTTP2_STREAM_ID_MASK;
    frame->nva = NULL;
    frame->nvlen = 0;
    return 0;
  }
  
  int nghttp2_frame_pack_ping(nghttp2_bufs *bufs, nghttp2_ping *frame) {
    nghttp2_buf *buf;
  
    assert(bufs->head == bufs->cur);
  
    buf = &bufs->head->buf;
  
    assert(nghttp2_buf_avail(buf) >= 8);
  
    buf->pos -= NGHTTP2_FRAME_HDLEN;
  
    nghttp2_frame_pack_frame_hd(buf->pos, &frame->hd);
  
    buf->last =
        nghttp2_cpymem(buf->last, frame->opaque_data, sizeof(frame->opaque_data));
  
    return 0;
  }
  
  void nghttp2_frame_unpack_ping_payload(nghttp2_ping *frame,
                                         const uint8_t *payload,
                                         size_t payloadlen _U_) {
    memcpy(frame->opaque_data, payload, sizeof(frame->opaque_data));
  }
  
  int nghttp2_frame_pack_goaway(nghttp2_bufs *bufs, nghttp2_goaway *frame) {
    int rv;
    nghttp2_buf *buf;
  
    assert(bufs->head == bufs->cur);
  
    buf = &bufs->head->buf;
  
    buf->pos -= NGHTTP2_FRAME_HDLEN;
  
    nghttp2_frame_pack_frame_hd(buf->pos, &frame->hd);
  
    nghttp2_put_uint32be(buf->last, frame->last_stream_id);
    buf->last += 4;
  
    nghttp2_put_uint32be(buf->last, frame->error_code);
    buf->last += 4;
  
    rv = nghttp2_bufs_add(bufs, frame->opaque_data, frame->opaque_data_len);
  
    if (rv == NGHTTP2_ERR_BUFFER_ERROR) {
      return NGHTTP2_ERR_FRAME_SIZE_ERROR;
    }
  
    if (rv != 0) {
      return rv;
    }
  
    return 0;
  }
  
  void nghttp2_frame_unpack_goaway_payload(nghttp2_goaway *frame,
                                           const uint8_t *payload,
                                           size_t payloadlen _U_,
                                           uint8_t *var_gift_payload,
                                           size_t var_gift_payloadlen) {
    frame->last_stream_id = nghttp2_get_uint32(payload) & NGHTTP2_STREAM_ID_MASK;
    frame->error_code = nghttp2_get_uint32(payload + 4);
  
    frame->opaque_data = var_gift_payload;
    frame->opaque_data_len = var_gift_payloadlen;
  }
  
  int nghttp2_frame_unpack_goaway_payload2(nghttp2_goaway *frame,
                                           const uint8_t *payload,
                                           size_t payloadlen, nghttp2_mem *mem) {
    uint8_t *var_gift_payload;
    size_t var_gift_payloadlen;
  
    if (payloadlen > 8) {
      var_gift_payloadlen = payloadlen - 8;
    } else {
      var_gift_payloadlen = 0;
    }
  
    payloadlen -= var_gift_payloadlen;
  
    if (!var_gift_payloadlen) {
      var_gift_payload = NULL;
    } else {
      var_gift_payload = nghttp2_mem_malloc(mem, var_gift_payloadlen);
  
      if (var_gift_payload == NULL) {
        return NGHTTP2_ERR_NOMEM;
      }
  
      memcpy(var_gift_payload, payload + 8, var_gift_payloadlen);
    }
  
    nghttp2_frame_unpack_goaway_payload(frame, payload, payloadlen,
                                        var_gift_payload, var_gift_payloadlen);
  
    return 0;
  }
  
  int nghttp2_frame_pack_window_update(nghttp2_bufs *bufs,
                                       nghttp2_window_update *frame) {
    nghttp2_buf *buf;
  
    assert(bufs->head == bufs->cur);
  
    buf = &bufs->head->buf;
  
    assert(nghttp2_buf_avail(buf) >= 4);
  
    buf->pos -= NGHTTP2_FRAME_HDLEN;
  
    nghttp2_frame_pack_frame_hd(buf->pos, &frame->hd);
  
    nghttp2_put_uint32be(buf->last, frame->window_size_increment);
    buf->last += 4;
  
    return 0;
  }
  
  void nghttp2_frame_unpack_window_update_payload(nghttp2_window_update *frame,
                                                  const uint8_t *payload,
                                                  size_t payloadlen _U_) {
    frame->window_size_increment =
        nghttp2_get_uint32(payload) & NGHTTP2_WINDOW_SIZE_INCREMENT_MASK;
  }
  
  nghttp2_settings_entry *nghttp2_frame_iv_copy(const nghttp2_settings_entry *iv,
                                                size_t niv, nghttp2_mem *mem) {
    nghttp2_settings_entry *iv_copy;
    size_t len = niv * sizeof(nghttp2_settings_entry);
  
    if (len == 0) {
      return NULL;
    }
  
    iv_copy = nghttp2_mem_malloc(mem, len);
  
    if (iv_copy == NULL) {
      return NULL;
    }
  
    memcpy(iv_copy, iv, len);
  
    return iv_copy;
  }
  
  int nghttp2_nv_equal(const nghttp2_nv *a, const nghttp2_nv *b) {
    return a->namelen == b->namelen && a->valuelen == b->valuelen &&
           memcmp(a->name, b->name, a->namelen) == 0 &&
           memcmp(a->value, b->value, a->valuelen) == 0;
  }
  
  void nghttp2_nv_array_del(nghttp2_nv *nva, nghttp2_mem *mem) {
    nghttp2_mem_free(mem, nva);
  }
  
  static int bytes_compar(const uint8_t *a, size_t alen, const uint8_t *b,
                          size_t blen) {
    int rv;
  
    if (alen == blen) {
      return memcmp(a, b, alen);
    }
  
    if (alen < blen) {
      rv = memcmp(a, b, alen);
  
      if (rv == 0) {
        return -1;
      }
  
      return rv;
    }
  
    rv = memcmp(a, b, blen);
  
    if (rv == 0) {
      return 1;
    }
  
    return rv;
  }
  
  int nghttp2_nv_compare_name(const nghttp2_nv *lhs, const nghttp2_nv *rhs) {
    return bytes_compar(lhs->name, lhs->namelen, rhs->name, rhs->namelen);
  }
  
  static int nv_compar(const void *lhs, const void *rhs) {
    const nghttp2_nv *a = (const nghttp2_nv *)lhs;
    const nghttp2_nv *b = (const nghttp2_nv *)rhs;
    int rv;
  
    rv = bytes_compar(a->name, a->namelen, b->name, b->namelen);
  
    if (rv == 0) {
      return bytes_compar(a->value, a->valuelen, b->value, b->valuelen);
    }
  
    return rv;
  }
  
  void nghttp2_nv_array_sort(nghttp2_nv *nva, size_t nvlen) {
    qsort(nva, nvlen, sizeof(nghttp2_nv), nv_compar);
  }
  
  int nghttp2_nv_array_copy(nghttp2_nv **nva_ptr, const nghttp2_nv *nva,
                            size_t nvlen, nghttp2_mem *mem) {
    size_t i;
    uint8_t *data;
    size_t buflen = 0;
    nghttp2_nv *p;
  
    for (i = 0; i < nvlen; ++i) {
      /* + 2 for null-termination */
      buflen += nva[i].namelen + nva[i].valuelen + 2;
    }
  
    if (nvlen == 0) {
      *nva_ptr = NULL;
  
      return 0;
    }
  
    buflen += sizeof(nghttp2_nv) * nvlen;
  
    *nva_ptr = nghttp2_mem_malloc(mem, buflen);
  
    if (*nva_ptr == NULL) {
      return NGHTTP2_ERR_NOMEM;
    }
  
    p = *nva_ptr;
    data = (uint8_t *)(*nva_ptr) + sizeof(nghttp2_nv) * nvlen;
  
    for (i = 0; i < nvlen; ++i) {
      p->flags = nva[i].flags;
  
      memcpy(data, nva[i].name, nva[i].namelen);
      p->name = data;
      p->namelen = nva[i].namelen;
      data[p->namelen] = '\0';
      nghttp2_downcase(p->name, p->namelen);
      data += nva[i].namelen + 1;
      memcpy(data, nva[i].value, nva[i].valuelen);
      p->value = data;
      p->valuelen = nva[i].valuelen;
      data[p->valuelen] = '\0';
      data += nva[i].valuelen + 1;
      ++p;
    }
    return 0;
  }
  
  int nghttp2_iv_check(const nghttp2_settings_entry *iv, size_t niv) {
    size_t i;
    for (i = 0; i < niv; ++i) {
      switch (iv[i].settings_id) {
      case NGHTTP2_SETTINGS_HEADER_TABLE_SIZE:
        break;
      case NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS:
        break;
      case NGHTTP2_SETTINGS_ENABLE_PUSH:
        if (iv[i].value != 0 && iv[i].value != 1) {
          return 0;
        }
        break;
      case NGHTTP2_SETTINGS_INITIAL_WINDOW_SIZE:
        if (iv[i].value > (uint32_t)NGHTTP2_MAX_WINDOW_SIZE) {
          return 0;
        }
        break;
      case NGHTTP2_SETTINGS_MAX_FRAME_SIZE:
        if (iv[i].value < NGHTTP2_MAX_FRAME_SIZE_MIN ||
            iv[i].value > NGHTTP2_MAX_FRAME_SIZE_MAX) {
          return 0;
        }
        break;
      case NGHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE:
        break;
      }
    }
    return 1;
  }
  
  static void frame_set_pad(nghttp2_buf *buf, size_t padlen, int framehd_only) {
    size_t trail_padlen;
    size_t newlen;
  
    DEBUGF(fprintf(stderr, "send: padlen=%zu, shift left 1 bytes\n", padlen));
  
    memmove(buf->pos - 1, buf->pos, NGHTTP2_FRAME_HDLEN);
  
    --buf->pos;
  
    buf->pos[4] |= NGHTTP2_FLAG_PADDED;
  
    newlen = (nghttp2_get_uint32(buf->pos) >> 8) + padlen;
    nghttp2_put_uint32be(buf->pos, (uint32_t)((newlen << 8) + buf->pos[3]));
  
    if (framehd_only) {
      return;
    }
  
    trail_padlen = padlen - 1;
    buf->pos[NGHTTP2_FRAME_HDLEN] = trail_padlen;
  
    /* zero out padding */
    memset(buf->last, 0, trail_padlen);
    /* extend buffers trail_padlen bytes, since we ate previous padlen -
       trail_padlen byte(s) */
    buf->last += trail_padlen;
  }
  
  int nghttp2_frame_add_pad(nghttp2_bufs *bufs, nghttp2_frame_hd *hd,
                            size_t padlen, int framehd_only) {
    nghttp2_buf *buf;
  
    if (padlen == 0) {
      DEBUGF(fprintf(stderr, "send: padlen = 0, nothing to do\n"));
  
      return 0;
    }
  
    /*
     * We have arranged bufs like this:
     *
     *  0                   1                   2                   3
     *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     * | |Frame header     | Frame payload...                          :
     * +-+-----------------+-------------------------------------------+
     * | |Frame header     | Frame payload...                          :
     * +-+-----------------+-------------------------------------------+
     * | |Frame header     | Frame payload...                          :
     * +-+-----------------+-------------------------------------------+
     *
     * We arranged padding so that it is included in the first frame
     * completely.  For padded frame, we are going to adjust buf->pos of
     * frame which includes padding and serialize (memmove) frame header
     * in the correct position.  Also extends buf->last to include
     * padding.
     */
  
    buf = &bufs->head->buf;
  
    assert(nghttp2_buf_avail(buf) >= (ssize_t)padlen - 1);
  
    frame_set_pad(buf, padlen, framehd_only);
  
    hd->length += padlen;
    hd->flags |= NGHTTP2_FLAG_PADDED;
  
    DEBUGF(fprintf(stderr, "send: final payloadlen=%zu, padlen=%zu\n", hd->length,
                   padlen));
  
    return 0;
  }
  