ESP32/main/network/mdns_airplay.c

#include "esp_log.h"
#include "esp_mac.h"
#include "mdns.h"
#include <stdio.h>
#include <string.h>

#include "hap.h"
#include "mdns_airplay.h"
#include "rtsp_handlers.h"
#include "wifi.h"
#include "settings.h"

static const char *TAG = "mdns_airplay";

// Feature flags are defined in rtsp_handlers.h (shared with /info handler)

// Protocol version
#ifdef CONFIG_AIRPLAY_FORCE_V1
#define AIRPLAY_PROTOCOL_VERSION "1"
#else
#define AIRPLAY_PROTOCOL_VERSION "2"
#endif
#define AIRPLAY_SOURCE_VERSION "377.40.00"

// Flags: 0x4 = audio receiver
#define AIRPLAY_FLAGS "0x4"

// Metadata types advertised in the "md" txt record:
//   0 = text (track title/artist/album), 1 = artwork (cover art images),
//   2 = progress.
// When artwork is disabled, drop "1" so senders do not transmit cover art
// (which can stall the audio pipeline and cause drop-outs on realtime
// streams) while still sending text and progress metadata.
#ifdef CONFIG_ENABLE_AIRPLAY_ARTWORK
#define AIRPLAY_METADATA_TYPES "0,1,2"
#else
#define AIRPLAY_METADATA_TYPES "0,2"
#endif

// Model identifier - AudioAccessory for speaker appearance
// AppleTV3,2 = Apple TV, AudioAccessory5,1 = HomePod mini (speaker)
#define AIRPLAY_MODEL "AudioAccessory5,1"

void mdns_airplay_init(void) {
  char mac_str[18];
  char device_id[18];
  char features_str[32];
  char service_name[80];
  char pk_str[65]; // 32 bytes = 64 hex chars + null
  char device_name[65];

  // Get device name from settings
  settings_get_device_name(device_name, sizeof(device_name));

  // Get MAC address
  wifi_get_mac_str(mac_str, sizeof(mac_str));
  strncpy(device_id, mac_str, sizeof(device_id));

  // Get real Ed25519 public key from HAP module
  const uint8_t *pk = hap_get_public_key();
  for (int i = 0; i < 32; i++) {
    snprintf(pk_str + (size_t)i * 2, 3, "%02x", pk[i]);
  }

  // Format features as "hi,lo" hex string
  snprintf(features_str, sizeof(features_str), "0x%X,0x%X", AIRPLAY_FEATURES_LO,
           AIRPLAY_FEATURES_HI);

  // Create service name for RAOP: <mac>@<name>
  uint8_t mac[6];
  esp_read_mac(mac, ESP_MAC_WIFI_STA);
  snprintf(service_name, sizeof(service_name), "%02X%02X%02X%02X%02X%02X@%s",
           mac[0], mac[1], mac[2], mac[3], mac[4], mac[5], device_name);

  // Initialize mDNS
  ESP_ERROR_CHECK(mdns_init());

  // Set hostname
  ESP_ERROR_CHECK(mdns_hostname_set(device_name));

#ifndef CONFIG_AIRPLAY_FORCE_V1
  // ========================================
  // _airplay._tcp service (port 7000)
  // Only registered for AirPlay 2 mode
  // ========================================
  mdns_txt_item_t airplay_txt[] = {
      {"deviceid", device_id},
      {"features", features_str},
      {"flags", AIRPLAY_FLAGS},
      {"model", AIRPLAY_MODEL},
      {"pk", pk_str},
      {"pi", "00000000-0000-0000-0000-000000000000"}, // Pairing identity UUID
      {"srcvers", AIRPLAY_SOURCE_VERSION},
      {"vv", AIRPLAY_PROTOCOL_VERSION},
      {"acl", "0"},
  };

  esp_err_t err =
      mdns_service_add(device_name, "_airplay", "_tcp", 7000, airplay_txt,
                       sizeof(airplay_txt) / sizeof(airplay_txt[0]));
  if (err != ESP_OK) {
    ESP_LOGE(TAG, "Failed to add _airplay._tcp service: %s",
             esp_err_to_name(err));
  }
#endif

  // ========================================
  // _raop._tcp service (port 7000)
  // RAOP = Remote Audio Output Protocol
  // Service name format: <MAC>@<DeviceName>
  // ========================================
#ifdef CONFIG_AIRPLAY_FORCE_V1
  // AirPlay v1 (classic RAOP): match squeezelite-esp32 txt record format.
  // No features, no pk, no HAP pairing — just classic RAOP fields.
  mdns_txt_item_t raop_txt[] = {
      {"am", AIRPLAY_MODEL},
      {"tp", "UDP"},                  // Transport protocol
      {"sm", "false"},                // Sharing mode
      {"sv", "false"},                // Server version (unused)
      {"ek", "1"},                    // Encryption key available
      {"et", "0,1"},                  // Encryption types: none, RSA
      {"md", AIRPLAY_METADATA_TYPES}, // Metadata types
      {"cn", "0,1"},                  // Audio codecs: PCM, ALAC
      {"ch", "2"},                    // Channels
      {"ss", "16"},                   // Sample size (bits)
      {"sr", "44100"},                // Sample rate
      {"vn", "3"},                    // Version number
      {"txtvers", "1"},               // TXT record version
  };
#else
  // Dual-mode: include et=1 (RSA) so RAOP-only clients (TuneBlade, AirMusic,
  // shairtunes2, etc.) accept the advertisement, while keeping et=3,5 for
  // AirPlay 2 FairPlay/MFi-SAP. ek=1 advertises that an RSA-encrypted key
  // can be supplied via SDP rsaaeskey: at ANNOUNCE time.
  mdns_txt_item_t raop_txt[] = {
      {"am", AIRPLAY_MODEL},
      {"cn", "0,1,2,3"},              // Audio codecs: PCM, ALAC, AAC, AAC-ELD
      {"da", "true"},                 // Digest auth
      {"ek", "1"},                    // Encryption key available (RSA)
      {"et", "0,1,3,5"},              // Encryption types
      {"ft", features_str},           // Features (same as airplay)
      {"md", AIRPLAY_METADATA_TYPES}, // Metadata types
      {"pk", pk_str},                 // Public key
      {"sf", AIRPLAY_FLAGS},          // Status flags
      {"tp", "UDP"},                  // Transport protocol
      {"vn", "65537"},                // Version number
      {"vs", AIRPLAY_SOURCE_VERSION},
      {"vv", AIRPLAY_PROTOCOL_VERSION},
  };
#endif

  esp_err_t err_raop =
      mdns_service_add(service_name, "_raop", "_tcp", 7000, raop_txt,
                       sizeof(raop_txt) / sizeof(raop_txt[0]));
  if (err_raop != ESP_OK) {
    ESP_LOGE(TAG, "Failed to add _raop._tcp service: %s",
             esp_err_to_name(err_raop));
  }
}