circuitpython/ports/nrf/common-hal/_bleio/PacketBuffer.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2019-2020 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
* 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 <string.h>
#include <stdio.h>
#include "ble_drv.h"
#include "ble_gatts.h"
#include "nrf_nvic.h"
#include "lib/utils/interrupt_char.h"
#include "py/runtime.h"
#include "py/stream.h"
#include "shared-bindings/_bleio/__init__.h"
#include "shared-bindings/_bleio/Connection.h"
#include "shared-bindings/_bleio/PacketBuffer.h"
#include "supervisor/shared/tick.h"
STATIC void write_to_ringbuf(bleio_packet_buffer_obj_t *self, uint8_t *data, uint16_t len) {
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if (len + sizeof(uint16_t) > ringbuf_capacity(&self->ringbuf)) {
// This shouldn't happen but can if our buffer size was much smaller than
// the writes the client actually makes.
return;
}
// Push all the data onto the ring buffer.
uint8_t is_nested_critical_region;
sd_nvic_critical_region_enter(&is_nested_critical_region);
// Make room for the new value by dropping the oldest packets first.
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while (ringbuf_capacity(&self->ringbuf) - ringbuf_num_filled(&self->ringbuf) < len + sizeof(uint16_t)) {
uint16_t packet_length;
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ringbuf_get_n(&self->ringbuf, (uint8_t *)&packet_length, sizeof(uint16_t));
for (uint16_t i = 0; i < packet_length; i++) {
ringbuf_get(&self->ringbuf);
}
// set an overflow flag?
}
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ringbuf_put_n(&self->ringbuf, (uint8_t *)&len, sizeof(uint16_t));
ringbuf_put_n(&self->ringbuf, data, len);
sd_nvic_critical_region_exit(is_nested_critical_region);
}
STATIC uint32_t queue_next_write(bleio_packet_buffer_obj_t *self) {
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// Queue up the next outgoing buffer. We use two, one that has been passed to the SD for
// transmission (when packet_queued is true) and the other is `pending` and can still be
// modified. By primarily appending to the `pending` buffer we can reduce the protocol overhead
// of the lower level link and ATT layers.
self->packet_queued = false;
if (self->pending_size > 0) {
uint16_t conn_handle = self->conn_handle;
uint32_t err_code;
if (self->client) {
ble_gattc_write_params_t write_params = {
.write_op = self->write_type,
.handle = self->characteristic->handle,
.p_value = self->outgoing[self->pending_index],
.len = self->pending_size,
};
err_code = sd_ble_gattc_write(conn_handle, &write_params);
} else {
uint16_t hvx_len = self->pending_size;
ble_gatts_hvx_params_t hvx_params = {
.handle = self->characteristic->handle,
.type = self->write_type,
.offset = 0,
.p_len = &hvx_len,
.p_data = self->outgoing[self->pending_index],
};
err_code = sd_ble_gatts_hvx(conn_handle, &hvx_params);
}
if (err_code != NRF_SUCCESS) {
// On error, simply skip updating the pending buffers so that the next HVC or WRITE
// complete event triggers another attempt.
return err_code;
}
self->pending_size = 0;
self->pending_index = (self->pending_index + 1) % 2;
self->packet_queued = true;
}
return NRF_SUCCESS;
}
STATIC bool packet_buffer_on_ble_client_evt(ble_evt_t *ble_evt, void *param) {
const uint16_t evt_id = ble_evt->header.evt_id;
bleio_packet_buffer_obj_t *self = (bleio_packet_buffer_obj_t *)param;
if (evt_id == BLE_GAP_EVT_DISCONNECTED && self->conn_handle == ble_evt->evt.gap_evt.conn_handle) {
self->conn_handle = BLE_CONN_HANDLE_INVALID;
}
// Check if this is a GATTC event so we can make sure the conn_handle is valid.
if (evt_id < BLE_GATTC_EVT_BASE || evt_id > BLE_GATTC_EVT_LAST) {
return false;
}
uint16_t conn_handle = ble_evt->evt.gattc_evt.conn_handle;
if (conn_handle != self->conn_handle) {
return false;
}
switch (evt_id) {
case BLE_GATTC_EVT_HVX: {
// A remote service wrote to this characteristic.
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ble_gattc_evt_hvx_t *evt_hvx = &ble_evt->evt.gattc_evt.params.hvx;
// Must be a notification, and event handle must match the handle for my characteristic.
if (evt_hvx->handle == self->characteristic->handle) {
write_to_ringbuf(self, evt_hvx->data, evt_hvx->len);
if (evt_hvx->type == BLE_GATT_HVX_INDICATION) {
sd_ble_gattc_hv_confirm(conn_handle, evt_hvx->handle);
}
}
break;
}
case BLE_GATTC_EVT_WRITE_CMD_TX_COMPLETE:
queue_next_write(self);
break;
case BLE_GATTC_EVT_WRITE_RSP:
queue_next_write(self);
break;
default:
return false;
break;
}
return true;
}
STATIC bool packet_buffer_on_ble_server_evt(ble_evt_t *ble_evt, void *param) {
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bleio_packet_buffer_obj_t *self = (bleio_packet_buffer_obj_t *)param;
switch (ble_evt->header.evt_id) {
case BLE_GATTS_EVT_WRITE: {
uint16_t conn_handle = ble_evt->evt.gatts_evt.conn_handle;
// A client wrote to this server characteristic.
ble_gatts_evt_write_t *evt_write = &ble_evt->evt.gatts_evt.params.write;
// Event handle must match the handle for my characteristic.
if (evt_write->handle == self->characteristic->handle) {
if (self->conn_handle == BLE_CONN_HANDLE_INVALID) {
self->conn_handle = conn_handle;
} else if (self->conn_handle != conn_handle) {
return false;
}
write_to_ringbuf(self, evt_write->data, evt_write->len);
} else if (evt_write->handle == self->characteristic->cccd_handle) {
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uint16_t cccd = *((uint16_t *)evt_write->data);
if (cccd & BLE_GATT_HVX_NOTIFICATION) {
self->conn_handle = conn_handle;
} else {
self->conn_handle = BLE_CONN_HANDLE_INVALID;
}
}
break;
}
case BLE_GAP_EVT_DISCONNECTED:
if (self->conn_handle == ble_evt->evt.gap_evt.conn_handle) {
self->conn_handle = BLE_CONN_HANDLE_INVALID;
}
break;
case BLE_GATTS_EVT_HVN_TX_COMPLETE:
queue_next_write(self);
break;
default:
return false;
break;
}
return true;
}
void common_hal_bleio_packet_buffer_construct(
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bleio_packet_buffer_obj_t *self, bleio_characteristic_obj_t *characteristic,
size_t buffer_size, size_t max_packet_size) {
self->characteristic = characteristic;
self->client = self->characteristic->service->is_remote;
bleio_characteristic_properties_t incoming = self->characteristic->props & (CHAR_PROP_WRITE_NO_RESPONSE | CHAR_PROP_WRITE);
bleio_characteristic_properties_t outgoing = self->characteristic->props & (CHAR_PROP_NOTIFY | CHAR_PROP_INDICATE);
if (self->client) {
// Swap if we're the client.
bleio_characteristic_properties_t temp = incoming;
incoming = outgoing;
outgoing = temp;
self->conn_handle = bleio_connection_get_conn_handle(MP_OBJ_TO_PTR(self->characteristic->service->connection));
} else {
self->conn_handle = BLE_CONN_HANDLE_INVALID;
}
// Cap the packet size to our implementation limits.
self->max_packet_size = MIN(max_packet_size, BLE_GATTS_VAR_ATTR_LEN_MAX - 3);
if (incoming) {
if (!ringbuf_alloc(&self->ringbuf, buffer_size * (sizeof(uint16_t) + self->max_packet_size), false)) {
mp_raise_ValueError(translate("Buffer too large and unable to allocate"));
}
}
if (outgoing) {
self->packet_queued = false;
self->pending_index = 0;
self->pending_size = 0;
self->outgoing[0] = m_malloc(self->max_packet_size, false);
self->outgoing[1] = m_malloc(self->max_packet_size, false);
} else {
self->outgoing[0] = NULL;
self->outgoing[1] = NULL;
}
if (self->client) {
ble_drv_add_event_handler(packet_buffer_on_ble_client_evt, self);
if (incoming) {
// Prefer notify if both are available.
if (incoming & CHAR_PROP_NOTIFY) {
self->write_type = BLE_GATT_HVX_NOTIFICATION;
common_hal_bleio_characteristic_set_cccd(self->characteristic, true, false);
} else {
common_hal_bleio_characteristic_set_cccd(self->characteristic, false, true);
}
}
if (outgoing) {
self->write_type = BLE_GATT_OP_WRITE_REQ;
if (outgoing & CHAR_PROP_WRITE_NO_RESPONSE) {
self->write_type = BLE_GATT_OP_WRITE_CMD;
}
}
} else {
ble_drv_add_event_handler(packet_buffer_on_ble_server_evt, self);
if (outgoing) {
self->write_type = BLE_GATT_HVX_INDICATION;
if (outgoing & CHAR_PROP_NOTIFY) {
self->write_type = BLE_GATT_HVX_NOTIFICATION;
}
}
}
}
mp_int_t common_hal_bleio_packet_buffer_readinto(bleio_packet_buffer_obj_t *self, uint8_t *data, size_t len) {
if (self->conn_handle == BLE_CONN_HANDLE_INVALID) {
mp_raise_ConnectionError(translate("Not connected"));
}
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if (ringbuf_num_filled(&self->ringbuf) < 2) {
return 0;
}
// Copy received data. Lock out write interrupt handler while copying.
uint8_t is_nested_critical_region;
sd_nvic_critical_region_enter(&is_nested_critical_region);
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// Get packet length, which is in first two bytes of packet.
uint16_t packet_length;
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ringbuf_get_n(&self->ringbuf, (uint8_t *)&packet_length, sizeof(uint16_t));
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mp_int_t ret;
if (packet_length > len) {
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// Packet is longer than requested. Return negative of overrun value.
ret = len - packet_length;
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// Discard the packet if it's too large. Don't fill data.
while (packet_length--) {
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(void)ringbuf_get(&self->ringbuf);
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}
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} else {
// Read as much as possible, but might be shorter than len.
ringbuf_get_n(&self->ringbuf, data, packet_length);
ret = packet_length;
}
// Writes now OK.
sd_nvic_critical_region_exit(is_nested_critical_region);
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return ret;
}
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mp_int_t common_hal_bleio_packet_buffer_write(bleio_packet_buffer_obj_t *self, uint8_t *data, size_t len, uint8_t *header, size_t header_len) {
if (self->outgoing[0] == NULL) {
mp_raise_bleio_BluetoothError(translate("Writes not supported on Characteristic"));
}
if (self->conn_handle == BLE_CONN_HANDLE_INVALID) {
return -1;
}
uint16_t outgoing_packet_length = common_hal_bleio_packet_buffer_get_outgoing_packet_length(self);
uint16_t total_len = len + header_len;
if (total_len > outgoing_packet_length) {
// Supplied data will not fit in a single BLE packet.
mp_raise_ValueError_varg(translate("Total data to write is larger than %q"), MP_QSTR_outgoing_packet_length);
}
if (total_len > self->max_packet_size) {
// Supplied data will not fit in a single BLE packet.
mp_raise_ValueError_varg(translate("Total data to write is larger than %q"), MP_QSTR_max_packet_size);
}
outgoing_packet_length = MIN(outgoing_packet_length, self->max_packet_size);
if (len + self->pending_size > outgoing_packet_length) {
// No room to append len bytes to packet. Wait until we get a free buffer,
// and keep checking that we haven't been disconnected.
while (self->pending_size != 0 &&
self->conn_handle != BLE_CONN_HANDLE_INVALID &&
!mp_hal_is_interrupted()) {
RUN_BACKGROUND_TASKS;
}
}
if (self->conn_handle == BLE_CONN_HANDLE_INVALID ||
mp_hal_is_interrupted()) {
return -1;
}
size_t num_bytes_written = 0;
uint8_t is_nested_critical_region;
sd_nvic_critical_region_enter(&is_nested_critical_region);
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uint8_t *pending = self->outgoing[self->pending_index];
if (self->pending_size == 0) {
memcpy(pending, header, header_len);
self->pending_size += header_len;
num_bytes_written += header_len;
}
memcpy(pending + self->pending_size, data, len);
self->pending_size += len;
num_bytes_written += len;
sd_nvic_critical_region_exit(is_nested_critical_region);
// If no writes are queued then sneak in this data.
if (!self->packet_queued) {
queue_next_write(self);
}
return num_bytes_written;
}
mp_int_t common_hal_bleio_packet_buffer_get_incoming_packet_length(bleio_packet_buffer_obj_t *self) {
// If this PacketBuffer is coming from a remote service via NOTIFY or INDICATE
// the maximum size is what can be sent in one
// BLE packet. But we must be connected to know that value.
//
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// Otherwise it can be as long as the characteristic
// will permit, whether or not we're connected.
if (self->characteristic == NULL) {
return -1;
}
if (self->characteristic->service != NULL &&
self->characteristic->service->is_remote &&
(common_hal_bleio_characteristic_get_properties(self->characteristic) &
(CHAR_PROP_INDICATE | CHAR_PROP_NOTIFY))) {
// We are talking to a remote service, and data is arriving via NOTIFY or INDICATE.
if (self->conn_handle != BLE_CONN_HANDLE_INVALID) {
bleio_connection_internal_t *connection = bleio_conn_handle_to_connection(self->conn_handle);
if (connection) {
return common_hal_bleio_connection_get_max_packet_length(connection);
}
}
// There's no current connection, so we don't know the MTU, and
// we can't tell what the largest incoming packet length would be.
return -1;
}
return self->characteristic->max_length;
}
mp_int_t common_hal_bleio_packet_buffer_get_outgoing_packet_length(bleio_packet_buffer_obj_t *self) {
// If we are sending data via NOTIFY or INDICATE, the maximum size
// is what can be sent in one BLE packet. But we must be connected
// to know that value.
//
// Otherwise it can be as long as the characteristic
// will permit, whether or not we're connected.
if (self->characteristic == NULL) {
return -1;
}
if (self->characteristic->service != NULL &&
!self->characteristic->service->is_remote &&
(common_hal_bleio_characteristic_get_properties(self->characteristic) &
(CHAR_PROP_INDICATE | CHAR_PROP_NOTIFY))) {
// We are sending to a client, via NOTIFY or INDICATE.
if (self->conn_handle != BLE_CONN_HANDLE_INVALID) {
bleio_connection_internal_t *connection = bleio_conn_handle_to_connection(self->conn_handle);
if (connection) {
return MIN(MIN(common_hal_bleio_connection_get_max_packet_length(connection),
self->max_packet_size),
self->characteristic->max_length);
}
}
// There's no current connection, so we don't know the MTU, and
// we can't tell what the largest outgoing packet length would be.
return -1;
}
// If we are talking to a remote service, we'll be bound by the MTU. (We don't actually
// know the max size of the remote characteristic.)
if (self->characteristic->service != NULL &&
self->characteristic->service->is_remote) {
// We are talking to a remote service so we're writing.
if (self->conn_handle != BLE_CONN_HANDLE_INVALID) {
bleio_connection_internal_t *connection = bleio_conn_handle_to_connection(self->conn_handle);
if (connection) {
return MIN(common_hal_bleio_connection_get_max_packet_length(connection),
self->max_packet_size);
}
}
}
return MIN(self->characteristic->max_length, self->max_packet_size);
}
bool common_hal_bleio_packet_buffer_deinited(bleio_packet_buffer_obj_t *self) {
return self->characteristic == NULL;
}
void common_hal_bleio_packet_buffer_deinit(bleio_packet_buffer_obj_t *self) {
if (!common_hal_bleio_packet_buffer_deinited(self)) {
ble_drv_remove_event_handler(packet_buffer_on_ble_client_evt, self);
}
}