Openharmony軟總線之連接模塊分析
軟總線介紹
總線(Bus)是計算機各種功能部件之間傳送信息的公共通信干線，軟總線與總線協議類似存在相似的功能但又又差異。總線協議中多個設備通過公共通信干線來進行通信，設備需要具備收發數據功能。openharmony 軟總線需要將不同設備整合到一起，由于不同的設備通信存在差異，如wifi與藍牙之間通信存在差異，軟總線(bus)需要具備有處理不同類型設備之間通信功能。connect 模塊用于這種不同類型設備管理，當然也包含于不同模塊的連接管理，如認證模塊，
connection模塊
connection 包含的文件類型如下：
- connection
- │
- ├── ble #低功耗藍牙
- ├── br #藍牙
- ├── common
- ├── interface #外部調用接口
- ├── manager #設備模塊接入、啟停管理
- └── tcp #tcp
當前設備需要支持的藍牙/wifi/網口通信(目前藍牙應該沒有完善)，其他網口和wifi 都基于tcp協議。藍牙BLE/BR 基于藍牙協議，因此當設備A與設備B(wifi)tcp通信時，設備A與設備c(藍牙)同時需要具備有藍牙通信能力。
g_connManager
- ConnectFuncInterface *g_connManager[CONNECT_TYPE_MAX] = {0};
g_connManager 用于管理不同類型設備通信功能。其中支持的類似有CONNECT_TCP、CONNECT_BR及CONNECT_BLE。
- typedef enum {
- CONNECT_TCP = 1,
- CONNECT_BR,
- CONNECT_BLE,
- CONNECT_TYPE_MAX
- } ConnectType;
由于不同設備通信存在差異，需要通過回調來實現通信方式的配置，通信接口如下：
- typedef struct {
- int32_t (*ConnectDevice)(const ConnectOption *option, uint32_t requestId, const ConnectResult *result);
- int32_t (*PostBytes)(uint32_t connectionId, const char *data, int32_t len, int32_t pid, int32_t flag);
- int32_t (*DisconnectDevice)(uint32_t connectionId);
- int32_t (*DisconnectDeviceNow)(const ConnectOption *option);
- int32_t (*GetConnectionInfo)(uint32_t connectionId, ConnectionInfo *info);
- int32_t (*StartLocalListening)(const LocalListenerInfo *info);
- int32_t (*StopLocalListening)(const LocalListenerInfo *info);
- } ConnectFuncInterface;
設備啟動時通ConnServerInit 函數進行初始化。ConnInitTcp、ConnInitBr、ConnInitBle 分別對應3種通信設備類型的初始化
- ConnectFuncInterface *ConnInitTcp(const ConnectCallback *callback)
- {
- if (callback == NULL) {
- SoftBusLog(SOFTBUS_LOG_CONN, SOFTBUS_LOG_ERROR, "ConnectCallback is NULL.");
- return NULL;
- }
- if (InitProperty() != SOFTBUS_OK) {
- SoftBusLog(SOFTBUS_LOG_CONN, SOFTBUS_LOG_ERROR, "Can not InitProperty");
- return NULL;
- }
- ConnectFuncInterface *interface = SoftBusCalloc(sizeof(ConnectFuncInterface));
- if (interface == NULL) {
- SoftBusLog(SOFTBUS_LOG_CONN, SOFTBUS_LOG_ERROR, "InitTcp failed.");
- return NULL;
- }
- interface->ConnectDevice = TcpConnectDevice;
- interface->DisconnectDevice = TcpDisconnectDevice;
- interface->DisconnectDeviceNow = TcpDisconnectDeviceNow;
- interface->PostBytes = TcpPostBytes;
- interface->GetConnectionInfo = TcpGetConnectionInfo;
- interface->StartLocalListening = TcpStartListening;
- interface->StopLocalListening = TcpStopListening;
- g_tcpConnCallback = callback;
- if (g_tcpConnInfoList == NULL) {
- g_tcpConnInfoList = CreateSoftBusList();
- if (g_tcpConnInfoList == NULL) {
- SoftBusLog(SOFTBUS_LOG_CONN, SOFTBUS_LOG_ERROR, "Create tcpConnInfoList failed.");
- SoftBusFree(interface);
- return NULL;
- }
- g_tcpConnInfoList->cnt = 0;
- }
- if (g_tcpListener == NULL) {
- g_tcpListener = (SoftbusBaseListener *)SoftBusCalloc(sizeof(SoftbusBaseListener));
- if (g_tcpListener == NULL) {
- SoftBusFree(interface);
- DestroySoftBusList(g_tcpConnInfoList);
- g_tcpConnInfoList = NULL;
- return NULL;
- }
- }
- g_tcpListener->onConnectEvent = TcpOnConnectEvent;
- g_tcpListener->onDataEvent = TcpOnDataEvent;
- return interface;
- }
interface 接口為tcp 通信方式的配置，ConnectDevice 連接設備，DisconnectDevice 斷開連接，PostBytes 發送數據，GetConnectionInfo 獲取設備端信息，StartLocalListening 啟動監聽，StopLocalListening關閉監聽，注意，設備通過g_tcpListener 將設備掛載到軟總線(bus)上面。每個設備需要通過不同端口建立起服務端和客服端模式，服務端用于監聽數據請求。當有數據到來時，總線上面觸發，經過一系列處理，最終通過g_connManagerCb變量獲取對應數據。
- typedef struct {
- void (*OnConnected)(uint32_t connectionId, const ConnectionInfo *info);
- void (*OnDisconnected)(uint32_t connectionId, const ConnectionInfo *info);
- void (*OnDataReceived)(uint32_t connectionId, ConnModule moduleId, int64_t seq, char *data, int32_t len);
- } ConnectCallback;
數據接收函數
ConnManagerRecvData
- void ConnManagerRecvData(uint32_t connectionId, ConnModule moduleId, int64_t seq, char *data, int32_t len)
- {
- ConnListenerNode listener;
- int32_t ret;
- char* pkt = NULL;
- int32_t pktLen;
- if (data == NULL) {
- return;
- }
- if (len <= (int32_t)sizeof(ConnPktHead)) {
- SoftBusLog(SOFTBUS_LOG_CONN, SOFTBUS_LOG_ERROR, "len %d \r\n", len);
- return;
- }
- ret = GetListenerByModuleId(moduleId, &listener);
- if (ret == SOFTBUS_ERR) {
- SoftBusLog(SOFTBUS_LOG_CONN, SOFTBUS_LOG_ERROR, "GetListenerByModuleId fail moduleId %d \r\n", moduleId);
- return;
- }
- pktLen = len - sizeof(ConnPktHead);
- pkt = data + sizeof(ConnPktHead);
- listener.callback.OnDataReceived(connectionId, moduleId, seq, pkt, pktLen);
- return;
- }
軟總線通信模塊由不同模塊組合而成，如發現，認證等，當認證模塊通過connect 接入總線時，數據獲取流程為：softbus-> ConnManagerRecvData-> listener.callback.OnDataReceived，可以參考總線認證一塊測試用例。
當然由于當前軟總線功能不完善，部分數據流程存在不完善的情況。
