From 0193464f92e90f765242b6ce0837f009ee611cdb Mon Sep 17 00:00:00 2001 From: "J. Nick Koston" Date: Mon, 19 Jan 2026 17:34:49 -1000 Subject: [PATCH] [dsmr] Avoid std::string allocation for decryption key (#13375) --- esphome/components/dsmr/__init__.py | 22 +++------------------- esphome/components/dsmr/dsmr.cpp | 19 +++++++------------ esphome/components/dsmr/dsmr.h | 2 +- esphome/config_validation.py | 8 ++++---- 4 files changed, 15 insertions(+), 36 deletions(-) diff --git a/esphome/components/dsmr/__init__.py b/esphome/components/dsmr/__init__.py index 0ba68daf5d..386da3ce21 100644 --- a/esphome/components/dsmr/__init__.py +++ b/esphome/components/dsmr/__init__.py @@ -25,29 +25,13 @@ dsmr_ns = cg.esphome_ns.namespace("esphome::dsmr") Dsmr = dsmr_ns.class_("Dsmr", cg.Component, uart.UARTDevice) -def _validate_key(value): - value = cv.string_strict(value) - parts = [value[i : i + 2] for i in range(0, len(value), 2)] - if len(parts) != 16: - raise cv.Invalid("Decryption key must consist of 16 hexadecimal numbers") - parts_int = [] - if any(len(part) != 2 for part in parts): - raise cv.Invalid("Decryption key must be format XX") - for part in parts: - try: - parts_int.append(int(part, 16)) - except ValueError: - # pylint: disable=raise-missing-from - raise cv.Invalid("Decryption key must be hex values from 00 to FF") - - return "".join(f"{part:02X}" for part in parts_int) - - CONFIG_SCHEMA = cv.All( cv.Schema( { cv.GenerateID(): cv.declare_id(Dsmr), - cv.Optional(CONF_DECRYPTION_KEY): _validate_key, + cv.Optional(CONF_DECRYPTION_KEY): lambda value: cv.bind_key( + value, name="Decryption key" + ), cv.Optional(CONF_CRC_CHECK, default=True): cv.boolean, cv.Optional(CONF_GAS_MBUS_ID, default=1): cv.int_, cv.Optional(CONF_WATER_MBUS_ID, default=2): cv.int_, diff --git a/esphome/components/dsmr/dsmr.cpp b/esphome/components/dsmr/dsmr.cpp index 5c62aa93ab..c78d37bf5e 100644 --- a/esphome/components/dsmr/dsmr.cpp +++ b/esphome/components/dsmr/dsmr.cpp @@ -1,4 +1,5 @@ #include "dsmr.h" +#include "esphome/core/helpers.h" #include "esphome/core/log.h" #include @@ -294,8 +295,8 @@ void Dsmr::dump_config() { DSMR_TEXT_SENSOR_LIST(DSMR_LOG_TEXT_SENSOR, ) } -void Dsmr::set_decryption_key(const std::string &decryption_key) { - if (decryption_key.empty()) { +void Dsmr::set_decryption_key(const char *decryption_key) { + if (decryption_key == nullptr || decryption_key[0] == '\0') { ESP_LOGI(TAG, "Disabling decryption"); this->decryption_key_.clear(); if (this->crypt_telegram_ != nullptr) { @@ -305,21 +306,15 @@ void Dsmr::set_decryption_key(const std::string &decryption_key) { return; } - if (decryption_key.length() != 32) { - ESP_LOGE(TAG, "Error, decryption key must be 32 character long"); + if (!parse_hex(decryption_key, this->decryption_key_, 16)) { + ESP_LOGE(TAG, "Error, decryption key must be 32 hex characters"); + this->decryption_key_.clear(); return; } - this->decryption_key_.clear(); ESP_LOGI(TAG, "Decryption key is set"); // Verbose level prints decryption key - ESP_LOGV(TAG, "Using decryption key: %s", decryption_key.c_str()); - - char temp[3] = {0}; - for (int i = 0; i < 16; i++) { - strncpy(temp, &(decryption_key.c_str()[i * 2]), 2); - this->decryption_key_.push_back(std::strtoul(temp, nullptr, 16)); - } + ESP_LOGV(TAG, "Using decryption key: %s", decryption_key); if (this->crypt_telegram_ == nullptr) { this->crypt_telegram_ = new uint8_t[this->max_telegram_len_]; // NOLINT diff --git a/esphome/components/dsmr/dsmr.h b/esphome/components/dsmr/dsmr.h index 56ba75b5fa..b7e05a22b3 100644 --- a/esphome/components/dsmr/dsmr.h +++ b/esphome/components/dsmr/dsmr.h @@ -63,7 +63,7 @@ class Dsmr : public Component, public uart::UARTDevice { void dump_config() override; - void set_decryption_key(const std::string &decryption_key); + void set_decryption_key(const char *decryption_key); void set_max_telegram_length(size_t length) { this->max_telegram_len_ = length; } void set_request_pin(GPIOPin *request_pin) { this->request_pin_ = request_pin; } void set_request_interval(uint32_t interval) { this->request_interval_ = interval; } diff --git a/esphome/config_validation.py b/esphome/config_validation.py index 8e2fadbea8..b7ab02013d 100644 --- a/esphome/config_validation.py +++ b/esphome/config_validation.py @@ -1046,20 +1046,20 @@ def mac_address(value): return core.MACAddress(*parts_int) -def bind_key(value): +def bind_key(value, *, name="Bind key"): value = string_strict(value) parts = [value[i : i + 2] for i in range(0, len(value), 2)] if len(parts) != 16: - raise Invalid("Bind key must consist of 16 hexadecimal numbers") + raise Invalid(f"{name} must consist of 16 hexadecimal numbers") parts_int = [] if any(len(part) != 2 for part in parts): - raise Invalid("Bind key must be format XX") + raise Invalid(f"{name} must be format XX") for part in parts: try: parts_int.append(int(part, 16)) except ValueError: # pylint: disable=raise-missing-from - raise Invalid("Bind key must be hex values from 00 to FF") + raise Invalid(f"{name} must be hex values from 00 to FF") return "".join(f"{part:02X}" for part in parts_int)