text: /*
   * This file is part of the MicroPython project, http://micropython.org/
   *
   * The MIT License (MIT)
   *
   * Copyright (c) 2016 Paul Sokolovsky
   *
   * 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 <stdio.h>
  #include <stdint.h>
  #include <string.h>
  
  #include "py/runtime.h"
  #include "py/stream.h"
  #include "extmod/moduwebsocket.h"
  
  #if MICROPY_PY_UWEBSOCKET
  
  enum { FRAME_HEADER, FRAME_OPT, PAYLOAD, CONTROL };
  
  enum { BLOCKING_WRITE = 0x80 };
  
  typedef struct _mp_obj_websocket_t {
      mp_obj_base_t base;
      mp_obj_t sock;
      uint32_t msg_sz;
      byte mask[4];
      byte state;
      byte to_recv;
      byte mask_pos;
      byte buf_pos;
      byte buf[6];
      byte opts;
      // Copy of last data frame flags
      byte ws_flags;
      // Copy of current frame flags
      byte last_flags;
  } mp_obj_websocket_t;
  
  STATIC mp_uint_t websocket_write(mp_obj_t self_in, const void *buf, mp_uint_t size, int *errcode);
  
  STATIC mp_obj_t websocket_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
      mp_arg_check_num(n_args, n_kw, 1, 2, false);
      mp_get_stream_raise(args[0], MP_STREAM_OP_READ | MP_STREAM_OP_WRITE | MP_STREAM_OP_IOCTL);
      mp_obj_websocket_t *o = mp_obj_malloc(mp_obj_websocket_t, type);
      o->sock = args[0];
      o->state = FRAME_HEADER;
      o->to_recv = 2;
      o->mask_pos = 0;
      o->buf_pos = 0;
      o->opts = FRAME_TXT;
      if (n_args > 1 && args[1] == mp_const_true) {
          o->opts |= BLOCKING_WRITE;
      }
      return MP_OBJ_FROM_PTR(o);
  }
  
  STATIC mp_uint_t websocket_read(mp_obj_t self_in, void *buf, mp_uint_t size, int *errcode) {
      mp_obj_websocket_t *self = MP_OBJ_TO_PTR(self_in);
      const mp_stream_p_t *stream_p = mp_get_stream(self->sock);
      while (1) {
          if (self->to_recv != 0) {
              mp_uint_t out_sz = stream_p->read(self->sock, self->buf + self->buf_pos, self->to_recv, errcode);
              if (out_sz == 0 || out_sz == MP_STREAM_ERROR) {
                  return out_sz;
              }
              self->buf_pos += out_sz;
              self->to_recv -= out_sz;
              if (self->to_recv != 0) {
                  *errcode = MP_EAGAIN;
                  return MP_STREAM_ERROR;
              }
          }
  
          switch (self->state) {
              case FRAME_HEADER: {
                  // TODO: Split frame handling below is untested so far, so conservatively disable it
                  assert(self->buf[0] & 0x80);
  
                  // "Control frames MAY be injected in the middle of a fragmented message."
                  // So, they must be processed before data frames (and not alter
                  // self->ws_flags)
                  byte frame_type = self->buf[0];
                  self->last_flags = frame_type;
                  frame_type &= FRAME_OPCODE_MASK;
  
                  if ((self->buf[0] & FRAME_OPCODE_MASK) == FRAME_CONT) {
                      // Preserve previous frame type
                      self->ws_flags = (self->ws_flags & FRAME_OPCODE_MASK) | (self->buf[0] & ~FRAME_OPCODE_MASK);
                  } else {
                      self->ws_flags = self->buf[0];
                  }
  
                  // Reset mask in case someone will use "simplified" protocol
                  // without masks.
                  memset(self->mask, 0, sizeof(self->mask));
  
                  int to_recv = 0;
                  size_t sz = self->buf[1] & 0x7f;
                  if (sz == 126) {
                      // Msg size is next 2 bytes
                      to_recv += 2;
                  } else if (sz == 127) {
                      // Msg size is next 8 bytes
                      assert(0);
                  }
                  if (self->buf[1] & 0x80) {
                      // Next 4 bytes is mask
                      to_recv += 4;
                  }
  
                  self->buf_pos = 0;
                  self->to_recv = to_recv;
                  self->msg_sz = sz; // May be overridden by FRAME_OPT
                  if (to_recv != 0) {
                      self->state = FRAME_OPT;
                  } else {
                      if (frame_type >= FRAME_CLOSE) {
                          self->state = CONTROL;
                      } else {
                          self->state = PAYLOAD;
                      }
                  }
                  continue;
              }
  
              case FRAME_OPT: {
                  if ((self->buf_pos & 3) == 2) {
                      // First two bytes are message length
                      self->msg_sz = (self->buf[0] << 8) | self->buf[1];
                  }
                  if (self->buf_pos >= 4) {
                      // Last 4 bytes is mask
                      memcpy(self->mask, self->buf + self->buf_pos - 4, 4);
                  }
                  self->buf_pos = 0;
                  if ((self->last_flags & FRAME_OPCODE_MASK) >= FRAME_CLOSE) {
                      self->state = CONTROL;
                  } else {
                      self->state = PAYLOAD;
                  }
                  continue;
              }
  
              case PAYLOAD:
              case CONTROL: {
                  mp_uint_t out_sz = 0;
                  if (self->msg_sz == 0) {
                      // In case message had zero payload
                      goto no_payload;
                  }
  
                  size_t sz = MIN(size, self->msg_sz);
                  out_sz = stream_p->read(self->sock, buf, sz, errcode);
                  if (out_sz == 0 || out_sz == MP_STREAM_ERROR) {
                      return out_sz;
                  }
  
                  sz = out_sz;
                  for (byte *p = buf; sz--; p++) {
                      *p ^= self->mask[self->mask_pos++ & 3];
                  }
  
                  self->msg_sz -= out_sz;
                  if (self->msg_sz == 0) {
                      byte last_state;
                  no_payload:
                      last_state = self->state;
                      self->state = FRAME_HEADER;
                      self->to_recv = 2;
                      self->mask_pos = 0;
                      self->buf_pos = 0;
  
                      // Handle control frame
                      if (last_state == CONTROL) {
                          byte frame_type = self->last_flags & FRAME_OPCODE_MASK;
                          if (frame_type == FRAME_CLOSE) {
                              static const char close_resp[2] = {0x88, 0};
                              int err;
                              websocket_write(self_in, close_resp, sizeof(close_resp), &err);
                              return 0;
                          }
  
                          // DEBUG_printf("Finished receiving ctrl message %x, ignoring\n", self->last_flags);
                          continue;
                      }
                  }
  
                  if (out_sz != 0) {
                      return out_sz;
                  }
                  // Empty (data) frame received is not EOF
                  continue;
              }
  
          }
      }
  }
  
  STATIC mp_uint_t websocket_write(mp_obj_t self_in, const void *buf, mp_uint_t size, int *errcode) {
      mp_obj_websocket_t *self = MP_OBJ_TO_PTR(self_in);
      assert(size < 0x10000);
      byte header[4] = {0x80 | (self->opts & FRAME_OPCODE_MASK)};
      int hdr_sz;
      if (size < 126) {
          header[1] = size;
          hdr_sz = 2;
      } else {
          header[1] = 126;
          header[2] = size >> 8;
          header[3] = size & 0xff;
          hdr_sz = 4;
      }
  
      mp_obj_t dest[3];
      if (self->opts & BLOCKING_WRITE) {
          mp_load_method(self->sock, MP_QSTR_setblocking, dest);
          dest[2] = mp_const_true;
          mp_call_method_n_kw(1, 0, dest);
      }
  
      mp_uint_t out_sz = mp_stream_write_exactly(self->sock, header, hdr_sz, errcode);
      if (*errcode == 0) {
          out_sz = mp_stream_write_exactly(self->sock, buf, size, errcode);
      }
  
      if (self->opts & BLOCKING_WRITE) {
          dest[2] = mp_const_false;
          mp_call_method_n_kw(1, 0, dest);
      }
  
      if (*errcode != 0) {
          return MP_STREAM_ERROR;
      }
      return out_sz;
  }
  
  STATIC mp_uint_t websocket_ioctl(mp_obj_t self_in, mp_uint_t request, uintptr_t arg, int *errcode) {
      mp_obj_websocket_t *self = MP_OBJ_TO_PTR(self_in);
      switch (request) {
          case MP_STREAM_CLOSE:
              // TODO: Send close signaling to the other side, otherwise it's
              // abrupt close (connection abort).
              mp_stream_close(self->sock);
              return 0;
          case MP_STREAM_GET_DATA_OPTS:
              return self->ws_flags & FRAME_OPCODE_MASK;
          case MP_STREAM_SET_DATA_OPTS: {
              int cur = self->opts & FRAME_OPCODE_MASK;
              self->opts = (self->opts & ~FRAME_OPCODE_MASK) | (arg & FRAME_OPCODE_MASK);
              return cur;
          }
          default:
              *errcode = MP_EINVAL;
              return MP_STREAM_ERROR;
      }
  }
  
  STATIC const mp_rom_map_elem_t websocket_locals_dict_table[] = {
      { MP_ROM_QSTR(MP_QSTR_read), MP_ROM_PTR(&mp_stream_read_obj) },
      { MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&mp_stream_readinto_obj) },
      { MP_ROM_QSTR(MP_QSTR_readline), MP_ROM_PTR(&mp_stream_unbuffered_readline_obj) },
      { MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&mp_stream_write_obj) },
      { MP_ROM_QSTR(MP_QSTR_ioctl), MP_ROM_PTR(&mp_stream_ioctl_obj) },
      { MP_ROM_QSTR(MP_QSTR_close), MP_ROM_PTR(&mp_stream_close_obj) },
  };
  STATIC MP_DEFINE_CONST_DICT(websocket_locals_dict, websocket_locals_dict_table);
  
  STATIC const mp_stream_p_t websocket_stream_p = {
      .read = websocket_read,
      .write = websocket_write,
      .ioctl = websocket_ioctl,
  };
  
  STATIC const mp_obj_type_t websocket_type = {
      { &mp_type_type },
      .name = MP_QSTR_websocket,
      .make_new = websocket_make_new,
      .protocol = &websocket_stream_p,
      .locals_dict = (void *)&websocket_locals_dict,
  };
  
  STATIC const mp_rom_map_elem_t uwebsocket_module_globals_table[] = {
      { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_uwebsocket) },
      { MP_ROM_QSTR(MP_QSTR_websocket), MP_ROM_PTR(&websocket_type) },
  };
  
  STATIC MP_DEFINE_CONST_DICT(uwebsocket_module_globals, uwebsocket_module_globals_table);
  
  const mp_obj_module_t mp_module_uwebsocket = {
      .base = { &mp_type_module },
      .globals = (mp_obj_dict_t *)&uwebsocket_module_globals,
  };
  
  #endif // MICROPY_PY_UWEBSOCKET
  