[packet_transport] Extract packet encoding functionality (#8187)

esphome/components/packet_transport/__init__.py

@@ -0,0 +1,201 @@
+"""ESPHome packet transport component."""
+
+import hashlib
+import logging
+
+import esphome.codegen as cg
+from esphome.components.api import CONF_ENCRYPTION
+from esphome.components.binary_sensor import BinarySensor
+from esphome.components.sensor import Sensor
+import esphome.config_validation as cv
+from esphome.const import (
+    CONF_BINARY_SENSORS,
+    CONF_ID,
+    CONF_INTERNAL,
+    CONF_KEY,
+    CONF_NAME,
+    CONF_PLATFORM,
+    CONF_SENSORS,
+)
+from esphome.core import CORE
+from esphome.cpp_generator import MockObjClass
+
+CODEOWNERS = ["@clydebarrow"]
+AUTO_LOAD = ["xxtea"]
+
+packet_transport_ns = cg.esphome_ns.namespace("packet_transport")
+PacketTransport = packet_transport_ns.class_("PacketTransport", cg.PollingComponent)
+
+IS_PLATFORM_COMPONENT = True
+
+DOMAIN = "packet_transport"
+CONF_BROADCAST = "broadcast"
+CONF_BROADCAST_ID = "broadcast_id"
+CONF_PROVIDER = "provider"
+CONF_PROVIDERS = "providers"
+CONF_REMOTE_ID = "remote_id"
+CONF_PING_PONG_ENABLE = "ping_pong_enable"
+CONF_PING_PONG_RECYCLE_TIME = "ping_pong_recycle_time"
+CONF_ROLLING_CODE_ENABLE = "rolling_code_enable"
+CONF_TRANSPORT_ID = "transport_id"
+
+
+_LOGGER = logging.getLogger(__name__)
+
+
+def sensor_validation(cls: MockObjClass):
+    return cv.maybe_simple_value(
+        cv.Schema(
+            {
+                cv.Required(CONF_ID): cv.use_id(cls),
+                cv.Optional(CONF_BROADCAST_ID): cv.validate_id_name,
+            }
+        ),
+        key=CONF_ID,
+    )
+
+
+def provider_name_validate(value):
+    value = cv.valid_name(value)
+    if "_" in value:
+        _LOGGER.warning(
+            "Device names typically do not contain underscores - did you mean to use a hyphen in '%s'?",
+            value,
+        )
+    return value
+
+
+ENCRYPTION_SCHEMA = {
+    cv.Optional(CONF_ENCRYPTION): cv.maybe_simple_value(
+        cv.Schema(
+            {
+                cv.Required(CONF_KEY): cv.string,
+            }
+        ),
+        key=CONF_KEY,
+    )
+}
+
+PROVIDER_SCHEMA = cv.Schema(
+    {
+        cv.Required(CONF_NAME): provider_name_validate,
+    }
+).extend(ENCRYPTION_SCHEMA)
+
+
+def validate_(config):
+    if CONF_ENCRYPTION in config:
+        if CONF_SENSORS not in config and CONF_BINARY_SENSORS not in config:
+            raise cv.Invalid("No sensors or binary sensors to encrypt")
+    elif config[CONF_ROLLING_CODE_ENABLE]:
+        raise cv.Invalid("Rolling code requires an encryption key")
+    if config[CONF_PING_PONG_ENABLE]:
+        if not any(CONF_ENCRYPTION in p for p in config.get(CONF_PROVIDERS) or ()):
+            raise cv.Invalid("Ping-pong requires at least one encrypted provider")
+    return config
+
+
+TRANSPORT_SCHEMA = (
+    cv.polling_component_schema("15s")
+    .extend(
+        {
+            cv.Optional(CONF_ROLLING_CODE_ENABLE, default=False): cv.boolean,
+            cv.Optional(CONF_PING_PONG_ENABLE, default=False): cv.boolean,
+            cv.Optional(
+                CONF_PING_PONG_RECYCLE_TIME, default="600s"
+            ): cv.positive_time_period_seconds,
+            cv.Optional(CONF_SENSORS): cv.ensure_list(sensor_validation(Sensor)),
+            cv.Optional(CONF_BINARY_SENSORS): cv.ensure_list(
+                sensor_validation(BinarySensor)
+            ),
+            cv.Optional(CONF_PROVIDERS, default=[]): cv.ensure_list(PROVIDER_SCHEMA),
+        },
+    )
+    .extend(ENCRYPTION_SCHEMA)
+    .add_extra(validate_)
+)
+
+
+def transport_schema(cls):
+    return TRANSPORT_SCHEMA.extend({cv.GenerateID(): cv.declare_id(cls)})
+
+
+# Build a list of sensors for this platform
+CORE.data[DOMAIN] = {CONF_SENSORS: []}
+
+
+def get_sensors(transport_id):
+    """Return the list of sensors for this platform."""
+    return (
+        sensor
+        for sensor in CORE.data[DOMAIN][CONF_SENSORS]
+        if sensor[CONF_TRANSPORT_ID] == transport_id
+    )
+
+
+def validate_packet_transport_sensor(config):
+    if CONF_NAME in config and CONF_INTERNAL not in config:
+        raise cv.Invalid("Must provide internal: config when using name:")
+    CORE.data[DOMAIN][CONF_SENSORS].append(config)
+    return config
+
+
+def packet_transport_sensor_schema(base_schema):
+    return cv.All(
+        base_schema.extend(
+            {
+                cv.GenerateID(CONF_TRANSPORT_ID): cv.use_id(PacketTransport),
+                cv.Optional(CONF_REMOTE_ID): cv.string_strict,
+                cv.Required(CONF_PROVIDER): provider_name_validate,
+            }
+        ),
+        cv.has_at_least_one_key(CONF_ID, CONF_REMOTE_ID),
+        validate_packet_transport_sensor,
+    )
+
+
+def hash_encryption_key(config: dict):
+    return list(hashlib.sha256(config[CONF_KEY].encode()).digest())
+
+
+async def register_packet_transport(var, config):
+    var = await cg.register_component(var, config)
+    cg.add(var.set_rolling_code_enable(config[CONF_ROLLING_CODE_ENABLE]))
+    cg.add(var.set_ping_pong_enable(config[CONF_PING_PONG_ENABLE]))
+    cg.add(
+        var.set_ping_pong_recycle_time(
+            config[CONF_PING_PONG_RECYCLE_TIME].total_seconds
+        )
+    )
+    # Get directly configured providers, plus those from sensors and binary sensors
+    providers = {
+        sensor[CONF_PROVIDER] for sensor in get_sensors(config[CONF_ID])
+    }.union(x[CONF_NAME] for x in config[CONF_PROVIDERS])
+    for provider in providers:
+        cg.add(var.add_provider(provider))
+    for provider in config[CONF_PROVIDERS]:
+        name = provider[CONF_NAME]
+        if encryption := provider.get(CONF_ENCRYPTION):
+            cg.add(var.set_provider_encryption(name, hash_encryption_key(encryption)))
+
+    for sens_conf in config.get(CONF_SENSORS, ()):
+        sens_id = sens_conf[CONF_ID]
+        sensor = await cg.get_variable(sens_id)
+        bcst_id = sens_conf.get(CONF_BROADCAST_ID, sens_id.id)
+        cg.add(var.add_sensor(bcst_id, sensor))
+    for sens_conf in config.get(CONF_BINARY_SENSORS, ()):
+        sens_id = sens_conf[CONF_ID]
+        sensor = await cg.get_variable(sens_id)
+        bcst_id = sens_conf.get(CONF_BROADCAST_ID, sens_id.id)
+        cg.add(var.add_binary_sensor(bcst_id, sensor))
+
+    if encryption := config.get(CONF_ENCRYPTION):
+        cg.add(var.set_encryption_key(hash_encryption_key(encryption)))
+    return providers
+
+
+async def new_packet_transport(config):
+    var = cg.new_Pvariable(config[CONF_ID])
+    cg.add(var.set_platform_name(config[CONF_PLATFORM]))
+    providers = await register_packet_transport(var, config)
+    return var, providers

esphome/components/packet_transport/binary_sensor.py

@@ -0,0 +1,19 @@
+import esphome.codegen as cg
+from esphome.components import binary_sensor
+from esphome.const import CONF_ID
+
+from . import (
+    CONF_PROVIDER,
+    CONF_REMOTE_ID,
+    CONF_TRANSPORT_ID,
+    packet_transport_sensor_schema,
+)
+
+CONFIG_SCHEMA = packet_transport_sensor_schema(binary_sensor.binary_sensor_schema())
+
+
+async def to_code(config):
+    var = await binary_sensor.new_binary_sensor(config)
+    comp = await cg.get_variable(config[CONF_TRANSPORT_ID])
+    remote_id = str(config.get(CONF_REMOTE_ID) or config.get(CONF_ID))
+    cg.add(comp.add_remote_binary_sensor(config[CONF_PROVIDER], remote_id, var))

esphome/components/packet_transport/packet_transport.cpp

@@ -0,0 +1,534 @@
+#include "esphome/core/log.h"
+#include "esphome/core/application.h"
+#include "packet_transport.h"
+
+#include "esphome/components/xxtea/xxtea.h"
+
+namespace esphome {
+namespace packet_transport {
+/**
+ * Structure of a data packet; everything is little-endian
+ *
+ * --- In clear text ---
+ * MAGIC_NUMBER: 16 bits
+ * host name length: 1 byte
+ * host name: (length) bytes
+ * padding: 0 or more null bytes to a 4 byte boundary
+ *
+ * --- Encrypted (if key set) ----
+ * DATA_KEY: 1 byte: OR ROLLING_CODE_KEY:
+ *  Rolling code (if enabled): 8 bytes
+ * Ping keys: if any
+ * repeat:
+ *      PING_KEY: 1 byte
+ *      ping code: 4 bytes
+ * Sensors:
+ * repeat:
+ *      SENSOR_KEY: 1 byte
+ *      float value: 4 bytes
+ *      name length: 1 byte
+ *      name
+ * Binary Sensors:
+ * repeat:
+ *      BINARY_SENSOR_KEY: 1 byte
+ *      bool value: 1 bytes
+ *      name length: 1 byte
+ *      name
+ *
+ * Padded to a 4 byte boundary with nulls
+ *
+ * Structure of a ping request packet:
+ * --- In clear text ---
+ * MAGIC_PING: 16 bits
+ * host name length: 1 byte
+ * host name: (length) bytes
+ * Ping key (4 bytes)
+ *
+ */
+static const char *const TAG = "packet_transport";
+
+static size_t round4(size_t value) { return (value + 3) & ~3; }
+
+union FuData {
+  uint32_t u32;
+  float f32;
+};
+
+static const uint16_t MAGIC_NUMBER = 0x4553;
+static const uint16_t MAGIC_PING = 0x5048;
+static const uint32_t PREF_HASH = 0x45535043;
+enum DataKey {
+  ZERO_FILL_KEY,
+  DATA_KEY,
+  SENSOR_KEY,
+  BINARY_SENSOR_KEY,
+  PING_KEY,
+  ROLLING_CODE_KEY,
+};
+
+enum DecodeResult {
+  DECODE_OK,
+  DECODE_UNMATCHED,
+  DECODE_ERROR,
+  DECODE_EMPTY,
+};
+
+static const size_t MAX_PING_KEYS = 4;
+
+static inline void add(std::vector<uint8_t> &vec, uint32_t data) {
+  vec.push_back(data & 0xFF);
+  vec.push_back((data >> 8) & 0xFF);
+  vec.push_back((data >> 16) & 0xFF);
+  vec.push_back((data >> 24) & 0xFF);
+}
+
+class PacketDecoder {
+ public:
+  PacketDecoder(const uint8_t *buffer, size_t len) : buffer_(buffer), len_(len) {}
+
+  DecodeResult decode_string(char *data, size_t maxlen) {
+    if (this->position_ == this->len_)
+      return DECODE_EMPTY;
+    auto len = this->buffer_[this->position_];
+    if (len == 0 || this->position_ + 1 + len > this->len_ || len >= maxlen)
+      return DECODE_ERROR;
+    this->position_++;
+    memcpy(data, this->buffer_ + this->position_, len);
+    data[len] = 0;
+    this->position_ += len;
+    return DECODE_OK;
+  }
+
+  template<typename T> DecodeResult get(T &data) {
+    if (this->position_ + sizeof(T) > this->len_)
+      return DECODE_ERROR;
+    T value = 0;
+    for (size_t i = 0; i != sizeof(T); ++i) {
+      value += this->buffer_[this->position_++] << (i * 8);
+    }
+    data = value;
+    return DECODE_OK;
+  }
+
+  template<typename T> DecodeResult decode(uint8_t key, T &data) {
+    if (this->position_ == this->len_)
+      return DECODE_EMPTY;
+    if (this->buffer_[this->position_] != key)
+      return DECODE_UNMATCHED;
+    if (this->position_ + 1 + sizeof(T) > this->len_)
+      return DECODE_ERROR;
+    this->position_++;
+    T value = 0;
+    for (size_t i = 0; i != sizeof(T); ++i) {
+      value += this->buffer_[this->position_++] << (i * 8);
+    }
+    data = value;
+    return DECODE_OK;
+  }
+
+  template<typename T> DecodeResult decode(uint8_t key, char *buf, size_t buflen, T &data) {
+    if (this->position_ == this->len_)
+      return DECODE_EMPTY;
+    if (this->buffer_[this->position_] != key)
+      return DECODE_UNMATCHED;
+    this->position_++;
+    T value = 0;
+    for (size_t i = 0; i != sizeof(T); ++i) {
+      value += this->buffer_[this->position_++] << (i * 8);
+    }
+    data = value;
+    return this->decode_string(buf, buflen);
+  }
+
+  DecodeResult decode(uint8_t key) {
+    if (this->position_ == this->len_)
+      return DECODE_EMPTY;
+    if (this->buffer_[this->position_] != key)
+      return DECODE_UNMATCHED;
+    this->position_++;
+    return DECODE_OK;
+  }
+
+  size_t get_remaining_size() const { return this->len_ - this->position_; }
+
+  // align the pointer to the given byte boundary
+  bool bump_to(size_t boundary) {
+    auto newpos = this->position_;
+    auto offset = this->position_ % boundary;
+    if (offset != 0) {
+      newpos += boundary - offset;
+    }
+    if (newpos >= this->len_)
+      return false;
+    this->position_ = newpos;
+    return true;
+  }
+
+  bool decrypt(const uint32_t *key) {
+    if (this->get_remaining_size() % 4 != 0) {
+      return false;
+    }
+    xxtea::decrypt((uint32_t *) (this->buffer_ + this->position_), this->get_remaining_size() / 4, key);
+    return true;
+  }
+
+ protected:
+  const uint8_t *buffer_;
+  size_t len_;
+  size_t position_{};
+};
+
+static inline void add(std::vector<uint8_t> &vec, uint8_t data) { vec.push_back(data); }
+static inline void add(std::vector<uint8_t> &vec, uint16_t data) {
+  vec.push_back((uint8_t) data);
+  vec.push_back((uint8_t) (data >> 8));
+}
+static inline void add(std::vector<uint8_t> &vec, DataKey data) { vec.push_back(data); }
+static void add(std::vector<uint8_t> &vec, const char *str) {
+  auto len = strlen(str);
+  vec.push_back(len);
+  for (size_t i = 0; i != len; i++) {
+    vec.push_back(*str++);
+  }
+}
+
+void PacketTransport::setup() {
+  this->name_ = App.get_name().c_str();
+  if (strlen(this->name_) > 255) {
+    this->mark_failed();
+    this->status_set_error("Device name exceeds 255 chars");
+    return;
+  }
+  this->resend_ping_key_ = this->ping_pong_enable_;
+  this->pref_ = global_preferences->make_preference<uint32_t>(PREF_HASH, true);
+  if (this->rolling_code_enable_) {
+    // restore the upper 32 bits of the rolling code, increment and save.
+    this->pref_.load(&this->rolling_code_[1]);
+    this->rolling_code_[1]++;
+    this->pref_.save(&this->rolling_code_[1]);
+    // must make sure it's saved immediately
+    global_preferences->sync();
+    this->ping_key_ = random_uint32();
+    ESP_LOGV(TAG, "Rolling code incremented, upper part now %u", (unsigned) this->rolling_code_[1]);
+  }
+#ifdef USE_SENSOR
+  for (auto &sensor : this->sensors_) {
+    sensor.sensor->add_on_state_callback([this, &sensor](float x) {
+      this->updated_ = true;
+      sensor.updated = true;
+    });
+  }
+#endif
+#ifdef USE_BINARY_SENSOR
+  for (auto &sensor : this->binary_sensors_) {
+    sensor.sensor->add_on_state_callback([this, &sensor](bool value) {
+      this->updated_ = true;
+      sensor.updated = true;
+    });
+  }
+#endif
+  // initialise the header. This is invariant.
+  add(this->header_, MAGIC_NUMBER);
+  add(this->header_, this->name_);
+  // pad to a multiple of 4 bytes
+  while (this->header_.size() & 0x3)
+    this->header_.push_back(0);
+}
+
+void PacketTransport::init_data_() {
+  this->data_.clear();
+  if (this->rolling_code_enable_) {
+    add(this->data_, ROLLING_CODE_KEY);
+    add(this->data_, this->rolling_code_[0]);
+    add(this->data_, this->rolling_code_[1]);
+    this->increment_code_();
+  } else {
+    add(this->data_, DATA_KEY);
+  }
+  for (auto pkey : this->ping_keys_) {
+    add(this->data_, PING_KEY);
+    add(this->data_, pkey.second);
+  }
+}
+
+void PacketTransport::flush_() {
+  if (!this->should_send() || this->data_.empty())
+    return;
+  auto header_len = round4(this->header_.size());
+  auto len = round4(data_.size());
+  auto encode_buffer = std::vector<uint8_t>(round4(header_len + len));
+  memcpy(encode_buffer.data(), this->header_.data(), this->header_.size());
+  memcpy(encode_buffer.data() + header_len, this->data_.data(), this->data_.size());
+  if (this->is_encrypted_()) {
+    xxtea::encrypt((uint32_t *) (encode_buffer.data() + header_len), len / 4,
+                   (uint32_t *) this->encryption_key_.data());
+  }
+  this->send_packet(encode_buffer);
+}
+
+void PacketTransport::add_binary_data_(uint8_t key, const char *id, bool data) {
+  auto len = 1 + 1 + 1 + strlen(id);
+  if (len + this->header_.size() + this->data_.size() > this->get_max_packet_size()) {
+    this->flush_();
+  }
+  add(this->data_, key);
+  add(this->data_, (uint8_t) data);
+  add(this->data_, id);
+}
+void PacketTransport::add_data_(uint8_t key, const char *id, float data) {
+  FuData udata{.f32 = data};
+  this->add_data_(key, id, udata.u32);
+}
+
+void PacketTransport::add_data_(uint8_t key, const char *id, uint32_t data) {
+  auto len = 4 + 1 + 1 + strlen(id);
+  if (len + this->header_.size() + this->data_.size() > this->get_max_packet_size()) {
+    this->flush_();
+  }
+  add(this->data_, key);
+  add(this->data_, data);
+  add(this->data_, id);
+}
+void PacketTransport::send_data_(bool all) {
+  if (!this->should_send())
+    return;
+  this->init_data_();
+#ifdef USE_SENSOR
+  for (auto &sensor : this->sensors_) {
+    if (all || sensor.updated) {
+      sensor.updated = false;
+      this->add_data_(SENSOR_KEY, sensor.id, sensor.sensor->get_state());
+    }
+  }
+#endif
+#ifdef USE_BINARY_SENSOR
+  for (auto &sensor : this->binary_sensors_) {
+    if (all || sensor.updated) {
+      sensor.updated = false;
+      this->add_binary_data_(BINARY_SENSOR_KEY, sensor.id, sensor.sensor->state);
+    }
+  }
+#endif
+  this->flush_();
+  this->updated_ = false;
+}
+
+void PacketTransport::update() {
+  auto now = millis() / 1000;
+  if (this->last_key_time_ + this->ping_pong_recyle_time_ < now) {
+    this->resend_ping_key_ = this->ping_pong_enable_;
+    this->last_key_time_ = now;
+  }
+}
+
+void PacketTransport::add_key_(const char *name, uint32_t key) {
+  if (!this->is_encrypted_())
+    return;
+  if (this->ping_keys_.count(name) == 0 && this->ping_keys_.size() == MAX_PING_KEYS) {
+    ESP_LOGW(TAG, "Ping key from %s discarded", name);
+    return;
+  }
+  this->ping_keys_[name] = key;
+  this->updated_ = true;
+  ESP_LOGV(TAG, "Ping key from %s now %X", name, (unsigned) key);
+}
+
+static bool process_rolling_code(Provider &provider, PacketDecoder &decoder) {
+  uint32_t code0, code1;
+  if (decoder.get(code0) != DECODE_OK || decoder.get(code1) != DECODE_OK) {
+    ESP_LOGW(TAG, "Rolling code requires 8 bytes");
+    return false;
+  }
+  if (code1 < provider.last_code[1] || (code1 == provider.last_code[1] && code0 <= provider.last_code[0])) {
+    ESP_LOGW(TAG, "Rolling code for %s %08lX:%08lX is old", provider.name, (unsigned long) code1,
+             (unsigned long) code0);
+    return false;
+  }
+  provider.last_code[0] = code0;
+  provider.last_code[1] = code1;
+  ESP_LOGV(TAG, "Saw new rolling code for %s %08lX:%08lX", provider.name, (unsigned long) code1, (unsigned long) code0);
+  return true;
+}
+
+/**
+ * Process a received packet
+ */
+void PacketTransport::process_(std::vector<uint8_t> &data) {
+  auto ping_key_seen = !this->ping_pong_enable_;
+  PacketDecoder decoder((data.data()), data.size());
+  char namebuf[256]{};
+  uint8_t byte;
+  FuData rdata{};
+  uint16_t magic;
+  if (decoder.get(magic) != DECODE_OK) {
+    ESP_LOGD(TAG, "Short buffer");
+    return;
+  }
+  if (magic != MAGIC_NUMBER && magic != MAGIC_PING) {
+    ESP_LOGV(TAG, "Bad magic %X", magic);
+    return;
+  }
+
+  if (decoder.decode_string(namebuf, sizeof namebuf) != DECODE_OK) {
+    ESP_LOGV(TAG, "Bad hostname length");
+    return;
+  }
+  if (strcmp(this->name_, namebuf) == 0) {
+    ESP_LOGVV(TAG, "Ignoring our own data");
+    return;
+  }
+  if (magic == MAGIC_PING) {
+    uint32_t key;
+    if (decoder.get(key) != DECODE_OK) {
+      ESP_LOGW(TAG, "Bad ping request");
+      return;
+    }
+    this->add_key_(namebuf, key);
+    ESP_LOGV(TAG, "Updated ping key for %s to %08X", namebuf, (unsigned) key);
+    return;
+  }
+
+  if (this->providers_.count(namebuf) == 0) {
+    ESP_LOGVV(TAG, "Unknown hostname %s", namebuf);
+    return;
+  }
+  ESP_LOGV(TAG, "Found hostname %s", namebuf);
+
+#ifdef USE_SENSOR
+  auto &sensors = this->remote_sensors_[namebuf];
+#endif
+#ifdef USE_BINARY_SENSOR
+  auto &binary_sensors = this->remote_binary_sensors_[namebuf];
+#endif
+
+  if (!decoder.bump_to(4)) {
+    ESP_LOGW(TAG, "Bad packet length %zu", data.size());
+  }
+  auto len = decoder.get_remaining_size();
+  if (round4(len) != len) {
+    ESP_LOGW(TAG, "Bad payload length %zu", len);
+    return;
+  }
+
+  auto &provider = this->providers_[namebuf];
+  // if encryption not used with this host, ping check is pointless since it would be easily spoofed.
+  if (provider.encryption_key.empty())
+    ping_key_seen = true;
+
+  if (!provider.encryption_key.empty()) {
+    decoder.decrypt((const uint32_t *) provider.encryption_key.data());
+  }
+  if (decoder.get(byte) != DECODE_OK) {
+    ESP_LOGV(TAG, "No key byte");
+    return;
+  }
+
+  if (byte == ROLLING_CODE_KEY) {
+    if (!process_rolling_code(provider, decoder))
+      return;
+  } else if (byte != DATA_KEY) {
+    ESP_LOGV(TAG, "Expected rolling_key or data_key, got %X", byte);
+    return;
+  }
+  uint32_t key;
+  while (decoder.get_remaining_size() != 0) {
+    if (decoder.decode(ZERO_FILL_KEY) == DECODE_OK)
+      continue;
+    if (decoder.decode(PING_KEY, key) == DECODE_OK) {
+      if (key == this->ping_key_) {
+        ping_key_seen = true;
+        ESP_LOGV(TAG, "Found good ping key %X", (unsigned) key);
+      } else {
+        ESP_LOGV(TAG, "Unknown ping key %X", (unsigned) key);
+      }
+      continue;
+    }
+    if (!ping_key_seen) {
+      ESP_LOGW(TAG, "Ping key not seen");
+      this->resend_ping_key_ = true;
+      break;
+    }
+    if (decoder.decode(BINARY_SENSOR_KEY, namebuf, sizeof(namebuf), byte) == DECODE_OK) {
+      ESP_LOGV(TAG, "Got binary sensor %s %d", namebuf, byte);
+#ifdef USE_BINARY_SENSOR
+      if (binary_sensors.count(namebuf) != 0)
+        binary_sensors[namebuf]->publish_state(byte != 0);
+#endif
+      continue;
+    }
+    if (decoder.decode(SENSOR_KEY, namebuf, sizeof(namebuf), rdata.u32) == DECODE_OK) {
+      ESP_LOGV(TAG, "Got sensor %s %f", namebuf, rdata.f32);
+#ifdef USE_SENSOR
+      if (sensors.count(namebuf) != 0)
+        sensors[namebuf]->publish_state(rdata.f32);
+#endif
+      continue;
+    }
+    if (decoder.get(byte) == DECODE_OK) {
+      ESP_LOGW(TAG, "Unknown key %X", byte);
+      ESP_LOGD(TAG, "Buffer pos: %zu contents: %s", data.size() - decoder.get_remaining_size(),
+               format_hex_pretty(data).c_str());
+    }
+    break;
+  }
+}
+
+void PacketTransport::dump_config() {
+  ESP_LOGCONFIG(TAG, "Packet Transport:");
+  ESP_LOGCONFIG(TAG, "  Platform: %s", this->platform_name_);
+  ESP_LOGCONFIG(TAG, "  Encrypted: %s", YESNO(this->is_encrypted_()));
+  ESP_LOGCONFIG(TAG, "  Ping-pong: %s", YESNO(this->ping_pong_enable_));
+#ifdef USE_SENSOR
+  for (auto sensor : this->sensors_)
+    ESP_LOGCONFIG(TAG, "  Sensor: %s", sensor.id);
+#endif
+#ifdef USE_BINARY_SENSOR
+  for (auto sensor : this->binary_sensors_)
+    ESP_LOGCONFIG(TAG, "  Binary Sensor: %s", sensor.id);
+#endif
+  for (const auto &host : this->providers_) {
+    ESP_LOGCONFIG(TAG, "  Remote host: %s", host.first.c_str());
+    ESP_LOGCONFIG(TAG, "    Encrypted: %s", YESNO(!host.second.encryption_key.empty()));
+#ifdef USE_SENSOR
+    for (const auto &sensor : this->remote_sensors_[host.first.c_str()])
+      ESP_LOGCONFIG(TAG, "    Sensor: %s", sensor.first.c_str());
+#endif
+#ifdef USE_BINARY_SENSOR
+    for (const auto &sensor : this->remote_binary_sensors_[host.first.c_str()])
+      ESP_LOGCONFIG(TAG, "    Binary Sensor: %s", sensor.first.c_str());
+#endif
+  }
+}
+void PacketTransport::increment_code_() {
+  if (this->rolling_code_enable_) {
+    if (++this->rolling_code_[0] == 0) {
+      this->rolling_code_[1]++;
+      this->pref_.save(&this->rolling_code_[1]);
+      // must make sure it's saved immediately
+      global_preferences->sync();
+    }
+  }
+}
+
+void PacketTransport::loop() {
+  if (this->resend_ping_key_)
+    this->send_ping_pong_request_();
+  if (this->updated_) {
+    this->send_data_(this->resend_data_);
+  }
+}
+
+void PacketTransport::send_ping_pong_request_() {
+  if (!this->ping_pong_enable_ || !this->should_send())
+    return;
+  this->ping_key_ = random_uint32();
+  this->ping_header_.clear();
+  add(this->ping_header_, MAGIC_PING);
+  add(this->ping_header_, this->name_);
+  add(this->ping_header_, this->ping_key_);
+  this->send_packet(this->ping_header_);
+  this->resend_ping_key_ = false;
+  ESP_LOGV(TAG, "Sent new ping request %08X", (unsigned) this->ping_key_);
+}
+}  // namespace packet_transport
+}  // namespace esphome

esphome/components/packet_transport/packet_transport.h

@@ -0,0 +1,155 @@
+#pragma once
+
+#include "esphome/core/component.h"
+#include "esphome/core/preferences.h"
+#ifdef USE_SENSOR
+#include "esphome/components/sensor/sensor.h"
+#endif
+#ifdef USE_BINARY_SENSOR
+#include "esphome/components/binary_sensor/binary_sensor.h"
+#endif
+#
+#include <vector>
+#include <map>
+
+/**
+ * Providing packet encoding functions for exchanging data with a remote host.
+ *
+ * A transport is required to send the data; this is provided by a child class.
+ * The child class should implement the virtual functions send_packet_ and get_max_packet_size_.
+ * On receipt of a data packet, it should call `this->process_()` with the data.
+ */
+
+namespace esphome {
+namespace packet_transport {
+
+struct Provider {
+  std::vector<uint8_t> encryption_key;
+  const char *name;
+  uint32_t last_code[2];
+};
+
+#ifdef USE_SENSOR
+struct Sensor {
+  sensor::Sensor *sensor;
+  const char *id;
+  bool updated;
+};
+#endif
+#ifdef USE_BINARY_SENSOR
+struct BinarySensor {
+  binary_sensor::BinarySensor *sensor;
+  const char *id;
+  bool updated;
+};
+#endif
+
+class PacketTransport : public PollingComponent {
+ public:
+  void setup() override;
+  void loop() override;
+  void update() override;
+  void dump_config() override;
+
+#ifdef USE_SENSOR
+  void add_sensor(const char *id, sensor::Sensor *sensor) {
+    Sensor st{sensor, id, true};
+    this->sensors_.push_back(st);
+  }
+  void add_remote_sensor(const char *hostname, const char *remote_id, sensor::Sensor *sensor) {
+    this->add_provider(hostname);
+    this->remote_sensors_[hostname][remote_id] = sensor;
+  }
+#endif
+#ifdef USE_BINARY_SENSOR
+  void add_binary_sensor(const char *id, binary_sensor::BinarySensor *sensor) {
+    BinarySensor st{sensor, id, true};
+    this->binary_sensors_.push_back(st);
+  }
+
+  void add_remote_binary_sensor(const char *hostname, const char *remote_id, binary_sensor::BinarySensor *sensor) {
+    this->add_provider(hostname);
+    this->remote_binary_sensors_[hostname][remote_id] = sensor;
+  }
+#endif
+
+  void add_provider(const char *hostname) {
+    if (this->providers_.count(hostname) == 0) {
+      Provider provider;
+      provider.encryption_key = std::vector<uint8_t>{};
+      provider.last_code[0] = 0;
+      provider.last_code[1] = 0;
+      provider.name = hostname;
+      this->providers_[hostname] = provider;
+#ifdef USE_SENSOR
+      this->remote_sensors_[hostname] = std::map<std::string, sensor::Sensor *>();
+#endif
+#ifdef USE_BINARY_SENSOR
+      this->remote_binary_sensors_[hostname] = std::map<std::string, binary_sensor::BinarySensor *>();
+#endif
+    }
+  }
+
+  void set_encryption_key(std::vector<uint8_t> key) { this->encryption_key_ = std::move(key); }
+  void set_rolling_code_enable(bool enable) { this->rolling_code_enable_ = enable; }
+  void set_ping_pong_enable(bool enable) { this->ping_pong_enable_ = enable; }
+  void set_ping_pong_recycle_time(uint32_t recycle_time) { this->ping_pong_recyle_time_ = recycle_time; }
+  void set_provider_encryption(const char *name, std::vector<uint8_t> key) {
+    this->providers_[name].encryption_key = std::move(key);
+  }
+  void set_platform_name(const char *name) { this->platform_name_ = name; }
+
+ protected:
+  // child classes must implement this
+  virtual void send_packet(std::vector<uint8_t> &buf) const = 0;
+  virtual size_t get_max_packet_size() = 0;
+  virtual bool should_send() { return true; }
+
+  // to be called by child classes when a data packet is received.
+  void process_(std::vector<uint8_t> &data);
+  void send_data_(bool all);
+  void flush_();
+  void add_data_(uint8_t key, const char *id, float data);
+  void add_data_(uint8_t key, const char *id, uint32_t data);
+  void increment_code_();
+  void add_binary_data_(uint8_t key, const char *id, bool data);
+  void init_data_();
+
+  bool updated_{};
+  uint32_t ping_key_{};
+  uint32_t rolling_code_[2]{};
+  bool rolling_code_enable_{};
+  bool ping_pong_enable_{};
+  uint32_t ping_pong_recyle_time_{};
+  uint32_t last_key_time_{};
+  bool resend_ping_key_{};
+  bool resend_data_{};
+  const char *name_{};
+  ESPPreferenceObject pref_{};
+
+  std::vector<uint8_t> encryption_key_{};
+
+#ifdef USE_SENSOR
+  std::vector<Sensor> sensors_{};
+  std::map<std::string, std::map<std::string, sensor::Sensor *>> remote_sensors_{};
+#endif
+#ifdef USE_BINARY_SENSOR
+  std::vector<BinarySensor> binary_sensors_{};
+  std::map<std::string, std::map<std::string, binary_sensor::BinarySensor *>> remote_binary_sensors_{};
+#endif
+
+  std::map<std::string, Provider> providers_{};
+  std::vector<uint8_t> ping_header_{};
+  std::vector<uint8_t> header_{};
+  std::vector<uint8_t> data_{};
+  std::map<const char *, uint32_t> ping_keys_{};
+  const char *platform_name_{""};
+  void add_key_(const char *name, uint32_t key);
+  void send_ping_pong_request_();
+  void process_ping_request_(const char *name, uint8_t *ptr, size_t len);
+
+  inline bool is_encrypted_() { return !this->encryption_key_.empty(); }
+};
+
+}  // namespace packet_transport
+}  // namespace esphome

esphome/components/packet_transport/sensor.py

@@ -0,0 +1,19 @@
+import esphome.codegen as cg
+from esphome.components.sensor import new_sensor, sensor_schema
+from esphome.const import CONF_ID
+
+from . import (
+    CONF_PROVIDER,
+    CONF_REMOTE_ID,
+    CONF_TRANSPORT_ID,
+    packet_transport_sensor_schema,
+)
+
+CONFIG_SCHEMA = packet_transport_sensor_schema(sensor_schema())
+
+
+async def to_code(config):
+    var = await new_sensor(config)
+    comp = await cg.get_variable(config[CONF_TRANSPORT_ID])
+    remote_id = str(config.get(CONF_REMOTE_ID) or config.get(CONF_ID))
+    cg.add(comp.add_remote_sensor(config[CONF_PROVIDER], remote_id, var))