Merge remote-tracking branch 'upstream/mdns-config-hash' into integration

esphome/components/mdns/mdns_component.cpp

@@ -39,7 +39,8 @@ MDNS_STATIC_CONST_CHAR(SERVICE_TCP, "_tcp");
 // Wrap build-time defines into flash storage
 MDNS_STATIC_CONST_CHAR(VALUE_VERSION, ESPHOME_VERSION);
 
-void MDNSComponent::compile_records_(StaticVector<MDNSService, MDNS_SERVICE_COUNT> &services, char *mac_address_buf) {
+void MDNSComponent::compile_records_(StaticVector<MDNSService, MDNS_SERVICE_COUNT> &services, char *mac_address_buf,
+                                     char *config_hash_buf) {
   // IMPORTANT: The #ifdef blocks below must match COMPONENTS_WITH_MDNS_SERVICES
   // in mdns/__init__.py. If you add a new service here, update both locations.
 
@@ -47,6 +48,7 @@ void MDNSComponent::compile_records_(StaticVector<MDNSService, MDNS_SERVICE_COUN
   MDNS_STATIC_CONST_CHAR(SERVICE_ESPHOMELIB, "_esphomelib");
   MDNS_STATIC_CONST_CHAR(TXT_FRIENDLY_NAME, "friendly_name");
   MDNS_STATIC_CONST_CHAR(TXT_VERSION, "version");
+  MDNS_STATIC_CONST_CHAR(TXT_CONFIG_HASH, "config_hash");
   MDNS_STATIC_CONST_CHAR(TXT_MAC, "mac");
   MDNS_STATIC_CONST_CHAR(TXT_PLATFORM, "platform");
   MDNS_STATIC_CONST_CHAR(TXT_BOARD, "board");
@@ -63,7 +65,7 @@ void MDNSComponent::compile_records_(StaticVector<MDNSService, MDNS_SERVICE_COUN
     bool friendly_name_empty = friendly_name.empty();
 
     // Calculate exact capacity for txt_records
-    size_t txt_count = 3;  // version, mac, board (always present)
+    size_t txt_count = 4;  // version, config_hash, mac, board (always present)
     if (!friendly_name_empty) {
       txt_count++;  // friendly_name
     }
@@ -91,6 +93,9 @@ void MDNSComponent::compile_records_(StaticVector<MDNSService, MDNS_SERVICE_COUN
     }
     txt_records.push_back({MDNS_STR(TXT_VERSION), MDNS_STR(VALUE_VERSION)});
 
+    // Config hash: passed from caller (either member buffer or stack buffer depending on USE_MDNS_STORE_SERVICES)
+    txt_records.push_back({MDNS_STR(TXT_CONFIG_HASH), MDNS_STR(config_hash_buf)});
+
     // MAC address: passed from caller (either member buffer or stack buffer depending on USE_MDNS_STORE_SERVICES)
     txt_records.push_back({MDNS_STR(TXT_MAC), MDNS_STR(mac_address_buf)});
 

esphome/components/mdns/mdns_component.h

@@ -1,7 +1,10 @@
 #pragma once
 #include "esphome/core/defines.h"
 #ifdef USE_MDNS
+#include <cinttypes>
+#include <cstdio>
 #include <string>
+#include "esphome/core/application.h"
 #include "esphome/core/automation.h"
 #include "esphome/core/component.h"
 #include "esphome/core/helpers.h"
@@ -70,6 +73,9 @@ class MDNSComponent final : public Component
   void setup() override;
   void dump_config() override;
 
+  /// Size of buffer required for config hash hex string (8 hex chars + null terminator)
+  static constexpr size_t CONFIG_HASH_STR_SIZE = 9;
+
 #ifdef USE_MDNS_EVENT_DRIVEN_POLLING
   // LEAmDNS has meaningful work only during the probe+announce phase (3×250ms probes +
   // 8×1000ms announces, ~9s). Afterwards every internal timer is resetToNeverExpires()
@@ -136,16 +142,21 @@ class MDNSComponent final : public Component
 #ifdef USE_MDNS_STORE_SERVICES
     get_mac_address_into_buffer(this->mac_address_);
     char *mac_ptr = this->mac_address_;
+    char *cfg_ptr = this->config_hash_str_;
 #else
     char mac_address[MAC_ADDRESS_BUFFER_SIZE];
+    char config_hash_str[CONFIG_HASH_STR_SIZE];
     get_mac_address_into_buffer(mac_address);
     char *mac_ptr = mac_address;
+    char *cfg_ptr = config_hash_str;
 #endif
+    snprintf(cfg_ptr, CONFIG_HASH_STR_SIZE, "%08" PRIx32, App.get_config_hash());
 #else
     char *mac_ptr = nullptr;
+    char *cfg_ptr = nullptr;
 #endif
 
-    this->compile_records_(services, mac_ptr);
+    this->compile_records_(services, mac_ptr, cfg_ptr);
     platform_register(this, services);
   }
 
@@ -159,6 +170,8 @@ class MDNSComponent final : public Component
 #if defined(USE_API) && defined(USE_MDNS_STORE_SERVICES)
   /// Fixed buffer for MAC address (only needed when services are stored)
   char mac_address_[MAC_ADDRESS_BUFFER_SIZE];
+  /// Fixed buffer for config hash hex string (only needed when services are stored)
+  char config_hash_str_[CONFIG_HASH_STR_SIZE];
 #endif
 #ifdef USE_MDNS_STORE_SERVICES
   StaticVector<MDNSService, MDNS_SERVICE_COUNT> services_{};
@@ -167,7 +180,8 @@ class MDNSComponent final : public Component
   // RP2040 defers MDNS.begin() until the first IP-up event; this tracks that.
   bool initialized_{false};
 #endif
-  void compile_records_(StaticVector<MDNSService, MDNS_SERVICE_COUNT> &services, char *mac_address_buf);
+  void compile_records_(StaticVector<MDNSService, MDNS_SERVICE_COUNT> &services, char *mac_address_buf,
+                        char *config_hash_buf);
 };
 
 }  // namespace esphome::mdns