circuitpython/shared-bindings/_bleio/PacketBuffer.c
Scott Shawcroft aa28d4f315
Allow setting max_packet_size for PacketBuffer
This is handy for remote characteristics because it allows for
the PacketBuffer binding code to have the correct max size. This
PR also adds checks so we don't write outside the outgoing buffer.
2021-04-14 17:09:48 -07:00

252 lines
11 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2019 Scott Shawcroft for Adafruit Industries
*
* 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
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* THE SOFTWARE.
*/
#include "py/mperrno.h"
#include "py/ioctl.h"
#include "py/objproperty.h"
#include "py/runtime.h"
#include "py/stream.h"
#include "shared-bindings/_bleio/__init__.h"
#include "shared-bindings/_bleio/PacketBuffer.h"
#include "shared-bindings/_bleio/UUID.h"
#include "shared-bindings/util.h"
//| class PacketBuffer:
//| """Accumulates a Characteristic's incoming packets in a FIFO buffer and facilitates packet aware
//| outgoing writes. A packet's size is either the characteristic length or the maximum transmission
//| unit (MTU) minus overhead, whichever is smaller. The MTU can change so check `incoming_packet_length`
//| and `outgoing_packet_length` before creating a buffer to store data.
//|
//| When we're the server, we ignore all connections besides the first to subscribe to
//| notifications."""
//|
//| def __init__(self, characteristic: Characteristic, *, buffer_size: int, max_packet_size: int = None) -> None:
//| """Monitor the given Characteristic. Each time a new value is written to the Characteristic
//| add the newly-written bytes to a FIFO buffer.
//|
//| Monitor the given Characteristic. Each time a new value is written to the Characteristic
//| add the newly-written packet of bytes to a FIFO buffer.
//|
//| :param Characteristic characteristic: The Characteristic to monitor.
//| It may be a local Characteristic provided by a Peripheral Service, or a remote Characteristic
//| in a remote Service that a Central has connected to.
//| :param int buffer_size: Size of ring buffer (in packets of the Characteristic's maximum
//| length) that stores incoming packets coming from the peer.
//| :param int max_packet_size: Maximum size of packets. Overrides value from the characteristic.
//| (Remote characteristics may not have the correct length.)"""
//| ...
//|
STATIC mp_obj_t bleio_packet_buffer_make_new(const mp_obj_type_t *type, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_characteristic, ARG_buffer_size, ARG_max_packet_size };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_characteristic, MP_ARG_REQUIRED | MP_ARG_OBJ },
{ MP_QSTR_buffer_size, MP_ARG_KW_ONLY | MP_ARG_REQUIRED | MP_ARG_INT },
{ MP_QSTR_max_packet_size, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none}},
};
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
const mp_obj_t characteristic = args[ARG_characteristic].u_obj;
const mp_int_t buffer_size = args[ARG_buffer_size].u_int;
if (buffer_size < 1) {
mp_raise_ValueError_varg(translate("%q must be >= 1"), MP_QSTR_buffer_size);
}
if (!MP_OBJ_IS_TYPE(characteristic, &bleio_characteristic_type)) {
mp_raise_TypeError(translate("Expected a Characteristic"));
}
size_t max_packet_size = common_hal_bleio_characteristic_get_max_length(characteristic);
if (args[ARG_max_packet_size].u_obj != mp_const_none) {
max_packet_size = mp_obj_get_int(args[ARG_max_packet_size].u_obj);
}
bleio_packet_buffer_obj_t *self = m_new_obj(bleio_packet_buffer_obj_t);
self->base.type = &bleio_packet_buffer_type;
common_hal_bleio_packet_buffer_construct(self, MP_OBJ_TO_PTR(characteristic), buffer_size, max_packet_size);
return MP_OBJ_FROM_PTR(self);
}
STATIC void check_for_deinit(bleio_packet_buffer_obj_t *self) {
if (common_hal_bleio_packet_buffer_deinited(self)) {
raise_deinited_error();
}
}
//| def readinto(self, buf: WriteableBuffer) -> int:
//| """Reads a single BLE packet into the ``buf``. Raises an exception if the next packet is longer
//| than the given buffer. Use `incoming_packet_length` to read the maximum length of a single packet.
//|
//| :return: number of bytes read and stored into ``buf``
//| :rtype: int"""
//| ...
//|
STATIC mp_obj_t bleio_packet_buffer_readinto(mp_obj_t self_in, mp_obj_t buffer_obj) {
bleio_packet_buffer_obj_t *self = MP_OBJ_TO_PTR(self_in);
check_for_deinit(self);
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(buffer_obj, &bufinfo, MP_BUFFER_WRITE);
mp_int_t size = common_hal_bleio_packet_buffer_readinto(self, bufinfo.buf, bufinfo.len);
if (size < 0) {
mp_raise_ValueError_varg(translate("Buffer too short by %d bytes"), size * -1);
}
return MP_OBJ_NEW_SMALL_INT(size);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(bleio_packet_buffer_readinto_obj, bleio_packet_buffer_readinto);
//| def write(self, data: ReadableBuffer, *, header: Optional[bytes] = None) -> int:
//| """Writes all bytes from data into the same outgoing packet. The bytes from header are included
//| before data when the pending packet is currently empty.
//|
//| This does not block until the data is sent. It only blocks until the data is pending.
//|
//| :return: number of bytes written. May include header bytes when packet is empty.
//| :rtype: int"""
//| ...
//|
// TODO: Add a kwarg `merge=False` to dictate whether subsequent writes are merged into a pending
// one.
STATIC mp_obj_t bleio_packet_buffer_write(mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_data, ARG_header };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_data, MP_ARG_REQUIRED | MP_ARG_OBJ },
{ MP_QSTR_header, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none}},
};
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
bleio_packet_buffer_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
check_for_deinit(self);
mp_buffer_info_t data_bufinfo;
mp_get_buffer_raise(args[ARG_data].u_obj, &data_bufinfo, MP_BUFFER_READ);
mp_buffer_info_t header_bufinfo;
header_bufinfo.len = 0;
if (args[ARG_header].u_obj != mp_const_none) {
mp_get_buffer_raise(args[ARG_header].u_obj, &header_bufinfo, MP_BUFFER_READ);
}
mp_int_t num_bytes_written = common_hal_bleio_packet_buffer_write(
self, data_bufinfo.buf, data_bufinfo.len, header_bufinfo.buf, header_bufinfo.len);
if (num_bytes_written < 0) {
// TODO: Raise an error if not connected. Right now the not-connected error
// is unreliable, because common_hal_bleio_packet_buffer_write()
// checks for conn_handle being set, but setting that
// can be delayed because conn_handle is discovered by spying on
// gatts write events, which may not have been sent yet.
//
// IDEAL:
// mp_raise_ConnectionError(translate("Not connected"));
// TEMPORARY:
num_bytes_written = 0;
}
return MP_OBJ_NEW_SMALL_INT(num_bytes_written);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bleio_packet_buffer_write_obj, 1, bleio_packet_buffer_write);
//| def deinit(self) -> None:
//| """Disable permanently."""
//| ...
STATIC mp_obj_t bleio_packet_buffer_deinit(mp_obj_t self_in) {
bleio_packet_buffer_obj_t *self = MP_OBJ_TO_PTR(self_in);
common_hal_bleio_packet_buffer_deinit(self);
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(bleio_packet_buffer_deinit_obj, bleio_packet_buffer_deinit);
//| incoming_packet_length: int
//| """Maximum length in bytes of a packet we are reading."""
//|
STATIC mp_obj_t bleio_packet_buffer_get_incoming_packet_length(mp_obj_t self_in) {
bleio_packet_buffer_obj_t *self = MP_OBJ_TO_PTR(self_in);
mp_int_t size = common_hal_bleio_packet_buffer_get_incoming_packet_length(self);
if (size < 0) {
mp_raise_ValueError(translate("No connection: length cannot be determined"));
}
return MP_OBJ_NEW_SMALL_INT(size);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(bleio_packet_buffer_get_incoming_packet_length_obj, bleio_packet_buffer_get_incoming_packet_length);
const mp_obj_property_t bleio_packet_buffer_incoming_packet_length_obj = {
.base.type = &mp_type_property,
.proxy = { (mp_obj_t)&bleio_packet_buffer_get_incoming_packet_length_obj,
(mp_obj_t)&mp_const_none_obj,
(mp_obj_t)&mp_const_none_obj },
};
//| outgoing_packet_length: int
//| """Maximum length in bytes of a packet we are writing."""
//|
STATIC mp_obj_t bleio_packet_buffer_get_outgoing_packet_length(mp_obj_t self_in) {
bleio_packet_buffer_obj_t *self = MP_OBJ_TO_PTR(self_in);
mp_int_t size = common_hal_bleio_packet_buffer_get_outgoing_packet_length(self);
if (size < 0) {
mp_raise_ValueError(translate("No connection: length cannot be determined"));
}
return MP_OBJ_NEW_SMALL_INT(size);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(bleio_packet_buffer_get_outgoing_packet_length_obj, bleio_packet_buffer_get_outgoing_packet_length);
const mp_obj_property_t bleio_packet_buffer_outgoing_packet_length_obj = {
.base.type = &mp_type_property,
.proxy = { (mp_obj_t)&bleio_packet_buffer_get_outgoing_packet_length_obj,
(mp_obj_t)&mp_const_none_obj,
(mp_obj_t)&mp_const_none_obj },
};
STATIC const mp_rom_map_elem_t bleio_packet_buffer_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&bleio_packet_buffer_deinit_obj) },
// Standard stream methods.
{ MP_OBJ_NEW_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&bleio_packet_buffer_readinto_obj) },
{ MP_OBJ_NEW_QSTR(MP_QSTR_write), MP_ROM_PTR(&bleio_packet_buffer_write_obj) },
{ MP_OBJ_NEW_QSTR(MP_QSTR_incoming_packet_length), MP_ROM_PTR(&bleio_packet_buffer_incoming_packet_length_obj) },
{ MP_OBJ_NEW_QSTR(MP_QSTR_outgoing_packet_length), MP_ROM_PTR(&bleio_packet_buffer_outgoing_packet_length_obj) },
};
STATIC MP_DEFINE_CONST_DICT(bleio_packet_buffer_locals_dict, bleio_packet_buffer_locals_dict_table);
const mp_obj_type_t bleio_packet_buffer_type = {
{ &mp_type_type },
.name = MP_QSTR_PacketBuffer,
.make_new = bleio_packet_buffer_make_new,
.locals_dict = (mp_obj_dict_t *)&bleio_packet_buffer_locals_dict
};