m5stack · Forairaaaaa · Jul 2, 2026 · Jul 2, 2026
diff --git a/firmware/main/hal/hal_ble.cpp b/firmware/main/hal/hal_ble.cpp
@@ -7,38 +7,294 @@
 #include "utils/bleprph/bleprph.h"
 #include "utils/secret_logic/secret_logic.h"
 #include <ArduinoJson.hpp>
+#include <algorithm>
+#include <cstdint>
 #include <mooncake_log.h>
 #include <mooncake.h>
 #include <settings.h>
 #include <esp_mac.h>
 
-static const std::string_view _tag = "HAL-BLE";
+static const std::string_view _tag              = "HAL-BLE";
+static const uint8_t _ble_fragment_magic0       = 0xAA;
+static const uint8_t _ble_fragment_magic1       = 0x55;
+static const uint8_t _ble_fragment_magic2       = 0xC3;
+static const uint8_t _ble_fragment_version      = 1;
+static const uint16_t _ble_fragment_header_len  = 10;
+static const uint16_t _ble_fallback_payload_len = 20;
+static uint16_t _ble_dynamic_payload            = _ble_fallback_payload_len;
+
+using BleNotifyCallback = int (*)(const char*, uint16_t);
+
+static void _recordIncomingWritePayload(uint16_t len)
+{
+    if (len > _ble_dynamic_payload && len <= STACKCHAN_MAX_JSON_LEN) {
+        _ble_dynamic_payload = len;
+    }
+}
+
+static bool _sendFragmentedNotify(BleNotifyCallback notify, const char* json_data, uint16_t json_len, const char* tag)
+{
+    const uint16_t usable_payload = _ble_dynamic_payload;
+
+    if (json_data == nullptr || json_len == 0) {
+        return true;
+    }
+
+    if (json_len > STACKCHAN_MAX_JSON_LEN) {
+        mclog::tagWarn(_tag, "{} payload exceed max len: {}", tag, json_len);
+        return false;
+    }
+
+    if (json_len <= usable_payload) {
+        return notify(json_data, json_len) == 0;
+    }
+
+    if (usable_payload <= _ble_fragment_header_len) {
+        mclog::tagWarn(_tag, "{} mtu payload too small for fragmentation", tag);
+        return false;
+    }
+
+    const uint16_t max_chunk_payload = usable_payload - _ble_fragment_header_len;
+    const uint16_t total_packets     = (json_len + max_chunk_payload - 1) / max_chunk_payload;
+
+    if (total_packets == 0) {
+        mclog::tagWarn(_tag, "{} invalid packet count", tag);
+        return false;
+    }
+
+    mclog::tagInfo(_tag, "{} fragmented notify: total={}, mtu_payload={}, chunk_payload={}, packets={}", tag, json_len,
+                   usable_payload, max_chunk_payload, total_packets);
+
+    for (uint16_t idx = 0; idx < total_packets; idx++) {
+        const uint16_t start     = idx * max_chunk_payload;
+        const uint16_t chunk_len = std::min<uint16_t>(max_chunk_payload, json_len - start);
+
+        std::string packet;
+        packet.reserve(_ble_fragment_header_len + chunk_len);
+        packet.push_back(static_cast<char>(_ble_fragment_magic0));
+        packet.push_back(static_cast<char>(_ble_fragment_magic1));
+        packet.push_back(static_cast<char>(_ble_fragment_magic2));
+        packet.push_back(static_cast<char>(_ble_fragment_version));
+
+        packet.push_back(static_cast<char>((idx >> 8) & 0xFF));
+        packet.push_back(static_cast<char>(idx & 0xFF));
+        packet.push_back(static_cast<char>((total_packets >> 8) & 0xFF));
+        packet.push_back(static_cast<char>(total_packets & 0xFF));
+        packet.push_back(static_cast<char>((json_len >> 8) & 0xFF));
+        packet.push_back(static_cast<char>(json_len & 0xFF));
+
+        packet.append(json_data + start, json_data + start + chunk_len);
+
+        if (notify(packet.data(), static_cast<uint16_t>(packet.size())) != 0) {
+            mclog::tagWarn(_tag, "{} fragmented notify failed at packet={}", tag, idx);
+            return false;
+        }
+    }
+
+    return true;
+}
+
+class BleFragmentAssembler {
+public:
+    bool consume(const char* data, uint16_t len, std::string& out_data, uint16_t& out_len)
+    {
+        if (!isFragmentFrame(data, len)) {
+            out_data.assign(data, data + len);
+            reset();
+            out_len = len;
+            return true;
+        }
+
+        const auto* raw              = reinterpret_cast<const uint8_t*>(data);
+        const uint16_t packet_index  = (uint16_t(raw[4]) << 8) | uint16_t(raw[5]);
+        const uint16_t total_packets = (uint16_t(raw[6]) << 8) | uint16_t(raw[7]);
+        const uint16_t total_len     = (uint16_t(raw[8]) << 8) | uint16_t(raw[9]);
+        const uint16_t payload_len   = len - _ble_fragment_header_len;
+
+        if (total_packets == 0 || total_len == 0 || total_len > STACKCHAN_MAX_JSON_LEN) {
+            mclog::tagWarn(_tag, "ignore invalid fragment header: total_packets={}, total_len={}", total_packets,
+                           total_len);
+            reset();
+            return false;
+        }
+
+        if (!_assembling) {
+            if (packet_index != 0) {
+                mclog::tagWarn(_tag, "unexpected fragment index {}", packet_index);
+                return false;
+            }
+            start(total_len, total_packets);
+        } else if (packet_index == 0) {
+            // Allow the sender to resend the first packet and restart assembly.
+            start(total_len, total_packets);
+        } else if (packet_index != _expected_packet_index || total_packets != _expected_total_packets ||
+                   total_len != _expected_total_len) {
+            mclog::tagWarn(_tag, "fragment sequence mismatch: idx={} expected={}", packet_index,
+                           _expected_packet_index);
+            reset();
+            return false;
+        }
+
+        if (payload_len == 0) {
+            if (_expected_total_packets > 1) {
+                mclog::tagWarn(_tag, "empty fragment payload, total_packets={}", total_packets);
+                reset();
+                return false;
+            }
+            out_data = "";
+            out_len  = 0;
+            reset();
+            return true;
+        }
+
+        if (_buffer.size() + payload_len > _expected_total_len) {
+            mclog::tagWarn(_tag, "fragment payload overflow: idx={} expected_len={} current_len={} frag_len={}",
+                           packet_index, _expected_total_len, _buffer.size(), payload_len);
+            reset();
+            return false;
+        }
+
+        _buffer.append(reinterpret_cast<const char*>(raw + _ble_fragment_header_len), payload_len);
+        _expected_packet_index++;
+
+        if (_expected_packet_index < _expected_total_packets) {
+            if (_buffer.size() < _expected_total_len) {
+                return false;
+            }
+            mclog::tagWarn(_tag, "fragment frame too short before completion: expected_len={} received={}",
+                           _expected_total_len, _buffer.size());
+            reset();
+            return false;
+        }
+
+        if (_buffer.size() != _expected_total_len) {
+            mclog::tagWarn(_tag, "fragmented frame incomplete: expected={}, received={}", _expected_total_len,
+                           _buffer.size());
+            reset();
+            return false;
+        }
+
+        _buffer.push_back('\0');
+        out_data = _buffer.substr(0, _expected_total_len);
+        out_len  = _expected_total_len;
+        reset();
+        return true;
+    }
+
+private:
+    bool isFragmentFrame(const char* data, uint16_t len) const
+    {
+        if (len <= _ble_fragment_header_len || data == nullptr) {
+            return false;
+        }
+
+        const auto* raw = reinterpret_cast<const uint8_t*>(data);
+        return raw[0] == _ble_fragment_magic0 && raw[1] == _ble_fragment_magic1 && raw[2] == _ble_fragment_magic2 &&
+               raw[3] == _ble_fragment_version;
+    }
+
+    void start(uint16_t total_len, uint16_t total_packets)
+    {
+        _assembling             = true;
+        _expected_total_len     = total_len;
+        _expected_total_packets = total_packets;
+        _expected_packet_index  = 0;
+        _buffer.clear();
+        _buffer.reserve(total_len);
+    }
+
+    void reset()
+    {
+        _assembling             = false;
+        _expected_total_len     = 0;
+        _expected_total_packets = 0;
+        _expected_packet_index  = 0;
+        _buffer.clear();
+    }
+
+    bool _assembling                 = false;
+    uint16_t _expected_total_len     = 0;
+    uint16_t _expected_total_packets = 0;
+    uint16_t _expected_packet_index  = 0;
+    std::string _buffer;
+};
+
+static BleFragmentAssembler _motion_assembler;
+static BleFragmentAssembler _avatar_assembler;
+static BleFragmentAssembler _config_assembler;
+static BleFragmentAssembler _rgb_assembler;
+static std::string _motion_payload_cache;
+static std::string _avatar_payload_cache;
+static std::string _config_payload_cache;
+static std::string _rgb_payload_cache;
+
+static const char* _cachePayload(std::string& cache, const std::string& payload)
+{
+    cache = payload;
+    return cache.c_str();
+}
 
 static int _handle_ble_motion_write(const char* json_data, uint16_t len, uint16_t conn_handle)
 {
-    // mclog::tagInfo(_tag, "on motion:\n{}", json_data);
-    GetHAL().onBleMotionData.emit(json_data);
+    std::string payload;
+    uint16_t payload_len = len;
+    (void)conn_handle;
+    _recordIncomingWritePayload(len);
+    if (!_motion_assembler.consume(json_data, len, payload, payload_len)) {
+        return 0;
+    }
+    if (payload_len == 0) {
+        return 0;
+    }
+    GetHAL().onBleMotionData.emit(_cachePayload(_motion_payload_cache, payload));
     return 0;
 }
 
 static int _handle_ble_avatar_write(const char* json_data, uint16_t len, uint16_t conn_handle)
 {
-    // mclog::tagInfo(_tag, "on avatar:\n{}", json_data);
-    GetHAL().onBleAvatarData.emit(json_data);
+    std::string payload;
+    uint16_t payload_len = len;
+    (void)conn_handle;
+    _recordIncomingWritePayload(len);
+    if (!_avatar_assembler.consume(json_data, len, payload, payload_len)) {
+        return 0;
+    }
+    if (payload_len == 0) {
+        return 0;
+    }
+    GetHAL().onBleAvatarData.emit(_cachePayload(_avatar_payload_cache, payload));
     return 0;
 }
 
 static int _handle_ble_config_write(const char* json_data, uint16_t len, uint16_t conn_handle)
 {
-    // mclog::tagInfo(_tag, "on config:\n{}", json_data);
-    GetHAL().onBleConfigData.emit(json_data);
+    std::string payload;
+    uint16_t payload_len = len;
+    (void)conn_handle;
+    _recordIncomingWritePayload(len);
+    if (!_config_assembler.consume(json_data, len, payload, payload_len)) {
+        return 0;
+    }
+    if (payload_len == 0) {
+        return 0;
+    }
+    GetHAL().onBleConfigData.emit(_cachePayload(_config_payload_cache, payload));
     return 0;
 }
 
 static int _handle_ble_rgb_write(const char* json_data, uint16_t len, uint16_t conn_handle)
 {
-    // mclog::tagInfo(_tag, "on rgb:\n{}", json_data);
-    GetHAL().onBleRgbData.emit(json_data);
+    std::string payload;
+    uint16_t payload_len = len;
+    (void)conn_handle;
+    _recordIncomingWritePayload(len);
+    if (!_rgb_assembler.consume(json_data, len, payload, payload_len)) {
+        return 0;
+    }
+    if (payload_len == 0) {
+        return 0;
+    }
+    GetHAL().onBleRgbData.emit(_cachePayload(_rgb_payload_cache, payload));
     return 0;
 }
 
@@ -238,7 +494,16 @@ class WifiConfigServer {
 
         std::string json_str;
         ArduinoJson::serializeJson(doc, json_str);
-        stackchan_ble_notify_config(json_str.c_str(), json_str.length());
+        if (json_str.length() > UINT16_MAX) {
+            mclog::tagWarn(_tag, "Config notify payload too large: {}", json_str.length());
+            return;
+        }
+
+        const auto notify_ok = _sendFragmentedNotify(stackchan_ble_notify_config, json_str.c_str(),
+                                                     static_cast<uint16_t>(json_str.length()), "Config notify");
+        if (!notify_ok) {
+            mclog::tagWarn(_tag, "Config notify fragmented send failed");
+        }
     }
 };