软总线介绍
总线(Bus)是计算机各种功能部件之间传送信息的公共通信干线，软总线与总线协议类似存在相似的功能但又又差异。总线协议中多个设备通过公共通信干线来进行通信，设备需要具备收发数据功能。openharmony 软总线需要将不同设备整合到一起，由于不同的设备通信存在差异，如wifi与蓝牙之间通信存在差异，软总线(bus)需要具备有处理不同类型设备之间通信功能。connect 模块用于这种不同类型设备管理，当然也包含于不同模块的连接管理，如认证模块，
connection模块
connection 包含的文件类型如下：
- connection
- │
- ├── ble #低功耗蓝牙
- ├── br #蓝牙
- ├── common
- ├── interface #外部调用接口
- ├── manager #设备模块接入、启停管理
- └── tcp #tcp
当前设备需要支持的蓝牙/wifi/网口通信(目前蓝牙应该没有完善)，其他网口和wifi 都基于tcp协议。蓝牙BLE/BR 基于蓝牙协议，因此当设备A与设备B(wifi)tcp通信时，设备A与设备c(蓝牙)同时需要具备有蓝牙通信能力。
g_connManager
- ConnectFuncInterface *g_connManager[CONNECT_TYPE_MAX] = {0};
g_connManager 用于管理不同类型设备通信功能。其中支持的类似有CONNECT_TCP、CONNECT_BR及CONNECT_BLE。
- typedef enum {
- CONNECT_TCP = 1,
- CONNECT_BR,
- CONNECT_BLE,
- CONNECT_TYPE_MAX
- } ConnectType;
由于不同设备通信存在差异，需要通过回调来实现通信方式的配置，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;
设备启动时通ConnServerInit 函数进行初始化。ConnInitTcp、ConnInitBr、ConnInitBle 分别对应3种通信设备类型的初始化
- 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 接口为tcp 通信方式的配置，ConnectDevice 连接设备，DisconnectDevice 断开连接，PostBytes 发送数据，GetConnectionInfo 获取设备端信息，StartLocalListening 启动监听，StopLocalListening关闭监听，注意，设备通过g_tcpListener 将设备挂载到软总线(bus)上面。每个设备需要通过不同端口建立起服务端和客服端模式，服务端用于监听数据请求。当有数据到来时，总线上面触发，经过一系列处理，最终通过g_connManagerCb变量获取对应数据。
- 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;
数据接收函数
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;
- }
软总线通信模块由不同模块组合而成，如发现，认证等，当认证模块通过connect 接入总线时，数据获取流程为：softbus-> ConnManagerRecvData-> listener.callback.OnDataReceived，可以参考总线认证一块测试用例。
当然由于当前软总线功能不完善，部分数据流程存在不完善的情况。
