github/esphome
2
0
Fork 0
mirror of https://github.com/esphome/esphome.git synced 2026-06-24 12:17:23 +00:00
Code Issues Packages Projects Releases Wiki Activity

[esp32_ble_server] Honor client offset and MTU in long reads (#16458)

Browse Source
This commit is contained in:
J. Nick Koston
2026-05-19 10:14:15 -07:00
committed by GitHub
parent 80ed541032
commit 863af482ec
2 changed files with 20 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

48
esphome/components/esp32_ble_server/ble_characteristic.cpp
View File

@@ -196,43 +196,35 @@ void BLECharacteristic::gatts_event_handler(esp_gatts_cb_event_t event, esp_gatt
(*this->on_read_callback_)(param->read.conn_id);
}
uint16_t max_offset = 22;
// Use the client-supplied offset for long reads; short reads always start at 0.
// The Bluedroid stack truncates ATT_READ_RSP / ATT_READ_BLOB_RSP to MTU-1, so we
// just provide as much data as we have from the requested offset and let the stack
// handle framing. The client issues subsequent blob reads with increasing offsets
// until it has received the whole value.
const uint16_t offset = param->read.is_long ? param->read.offset : 0;
esp_gatt_status_t status = ESP_GATT_OK;
esp_gatt_rsp_t response;
if (param->read.is_long) {
if (this->value_read_offset_ >= this->value_.size()) {
response.attr_value.len = 0;
response.attr_value.offset = this->value_read_offset_;
this->value_read_offset_ = 0;
} else if (this->value_.size() - this->value_read_offset_ < max_offset) {
// Last message in the chain
response.attr_value.len = this->value_.size() - this->value_read_offset_;
response.attr_value.offset = this->value_read_offset_;
memcpy(response.attr_value.value, this->value_.data() + response.attr_value.offset, response.attr_value.len);
this->value_read_offset_ = 0;
} else {
response.attr_value.len = max_offset;
response.attr_value.offset = this->value_read_offset_;
memcpy(response.attr_value.value, this->value_.data() + response.attr_value.offset, response.attr_value.len);
this->value_read_offset_ += max_offset;
}
response.attr_value.offset = offset;
if (offset > this->value_.size()) {
status = ESP_GATT_INVALID_OFFSET;
response.attr_value.len = 0;
} else {
response.attr_value.offset = 0;
response.attr_value.len = this->value_.size();
if (response.attr_value.len > ESP_GATT_MAX_ATTR_LEN) {
ESP_LOGW(TAG, "Characteristic length %u exceeds buffer size of %u, truncating", response.attr_value.len,
ESP_GATT_MAX_ATTR_LEN);
response.attr_value.len = ESP_GATT_MAX_ATTR_LEN;
size_t remaining = this->value_.size() - offset;
if (remaining > ESP_GATT_MAX_ATTR_LEN) {
ESP_LOGW(TAG, "Characteristic length %u exceeds buffer size of %u, truncating",
static_cast<unsigned>(remaining), ESP_GATT_MAX_ATTR_LEN);
remaining = ESP_GATT_MAX_ATTR_LEN;
}
memcpy(response.attr_value.value, this->value_.data(), response.attr_value.len);
this->value_read_offset_ = 0;
response.attr_value.len = remaining;
memcpy(response.attr_value.value, this->value_.data() + offset, remaining);
}
response.attr_value.handle = this->handle_;
response.attr_value.auth_req = ESP_GATT_AUTH_REQ_NONE;
esp_err_t err =
esp_ble_gatts_send_response(gatts_if, param->read.conn_id, param->read.trans_id, ESP_GATT_OK, &response);
esp_ble_gatts_send_response(gatts_if, param->read.conn_id, param->read.trans_id, status, &response);
if (err != ESP_OK) {
ESP_LOGE(TAG, "esp_ble_gatts_send_response failed: %d", err);
}

1
esphome/components/esp32_ble_server/ble_characteristic.h
View File

@@ -79,7 +79,6 @@ class BLECharacteristic {
esp_gatt_char_prop_t properties_;
uint16_t handle_{0xFFFF};
uint16_t value_read_offset_{0};
std::vector<uint8_t> value_;
std::vector<BLEDescriptor *> descriptors_;