websocket_remove_frame() ToDo: Frame >= 32768 i.e len ==127 #47

int websocket_remove_frame(Network *n, unsigned char *framebuffer,
                           unsigned char *data, int framlen) {

  int bytepos = 0;
  int opcode;
  uint8_t mask_flag = 1;
  int mask_key[4] = {0x00, 0x00, 0x00, 0x00};
  int len;

  opcode = framebuffer[bytepos] & 0x0F;
  bytepos++;
  len = framebuffer[bytepos] & 0x7F;
  mask_flag = framebuffer[bytepos] >> 7;
  bytepos++;
  if (len == 126) {
    len = framebuffer[bytepos] << 8;
    bytepos++;
    len += framebuffer[bytepos];
    bytepos++;
  }
  if (len == 127) {
    len = 0; // ToDo : Frame >= 32768 i.e. len == 127
    goto exit;
  }

  if (len > framlen) {
    len = framlen;
  }
  if (mask_flag == 1) {
    mask_key[0] = framebuffer[bytepos];
    bytepos++;
    mask_key[1] = framebuffer[bytepos];
    bytepos++;
    mask_key[2] = framebuffer[bytepos];
    bytepos++;
    mask_key[3] = framebuffer[bytepos];
    bytepos++;
  }
  for (int i = 0; i < len; i++) {
    if (mask_flag == 1) {
      data[i] = framebuffer[bytepos + i] ^
                mask_key[i % 4]; // Bitwise XOR at index modulo 4
    } else {
      data[i] = framebuffer[bytepos + i];
    }
  }
  if (opcode == WEBSOCKET_CONNCLOSE || opcode == WEBSOCKET_PING) {
    if (opcode == WEBSOCKET_PING) {
      opcode = WEBSOCKET_PONG;
    }
    ESP_LOGD(TAG, "opcode %d websocket_mbedtls_write mqtt want %d", opcode,
             len);
    int framelen = websocket_create_frame(opcode, n->ws_sendbuf, data, len, 0);

    for (int i = 0; i < framelen; i++) {
      ESP_LOGD(TAG, "opcode websocket_mbedtls_write: %d %02X [%c]", i + 1,
               n->ws_sendbuf[i], n->ws_sendbuf[i]);
    }
    int ret = mbedtls_ssl_write(&n->ssl, n->ws_sendbuf, framelen);
    ESP_LOGD(TAG, "opcode mbedtls_ssl_write websocket %d from %d", ret, len);
  }

exit:
  return len;
}