Embedded sig | distributed soft bus

Embedded SIG

Distributed soft bus

- Feature introduction  -

background

openEuler Adhering to create “ Digital infrastructure operating system ” Vision , To promote and OpenHarmony Ecological cooperation and connectivity , Realize interoperability and collaboration in end-to-end fields , It is the first time to introduce distributed soft bus technology into the embedded field .

Distributed soft bus is OpenHarmony Community open source distributed device communication base , Provide unified distributed collaboration capability for interconnection between devices , Realize the senseless discovery and efficient transmission of devices .

OpenHarmony Mainly for intelligent terminals with strong interaction and other requirements 、 Internet of things terminals and industrial terminals .openEuler Mainly for high reliability 、 High performance servers 、 Edge of computing 、 Cloud and embedded devices , Both have their own emphases . Through the technology represented by distributed soft bus for ecological interoperability , With a view to achieving “1+1>2” The effect of , Support community users to develop a broader industry space .

framework

The main architecture of soft bus is as follows ：

The main functions of soft bus are divided into discovery 、 networking 、 Connect and transmit four basic modules , Realization ：

· Plug and play ： Quickly and conveniently discover peripheral devices .

· Free circulation ： Ad hoc network among equipment , Establish any business connection , Realize free communication .

· Efficient transmission ： adopt WIFI、 Under Bluetooth device, hardware and software cooperate to maximize hardware transmission performance .

Soft bus southbound supports standard Ethernet communication , At the same time, the follow-up sustainable development WIFI、 Bluetooth and other communication methods . And provide a unified API Interface , Shielding the underlying communication mechanism .

Soft bus depends on device authentication 、IPC、 Logs and system parameters （SN Number ） Wait for peripheral modules , These dependent modules are replaced by template in embedded system , To realize the basic functions of soft bus . The actual peripheral module function realization , Users also need to enrich and replace according to the actual business scenarios , To expand the soft bus capability .

- Application Guide  -

Deployment diagram

The soft bus supports the deployment of multiple devices in the LAN , The equipment communicates through Ethernet . Single equipment is divided into server and client, Both by IPC Modules interact .

Be careful ：

At present IPC Module and SN No. and other system parameters , The embedded version provides only reference templates , Multi node and multi client Deploy . Users can do it according to the actual business scenario IPC Module and SN No. 2 system parameters, rich functions , To expand the deployment capability of soft bus .

Server startup

The main program of the server is softbus_server_main, Executing the main program can pull up the soft bus server .

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```bashopeneuler ~ # softbus_server_main >log.file &```

When the server is pulled up , Will take the initiative to pass the name ethX Network equipment coap radio broadcast , If the presence of the opposite end device is detected, the ad hoc network will be started .

client API

Header file in sdk and initrd Are stored in /usr/include/dsoftbus/ Next , among ：

1. discovery\_service.h： Found module header file , Support application active detection and release API as follows ：

When the server is pulled up , Will take the initiative to pass the name ethX Network equipment coap radio broadcast , If the presence of the opposite end device is detected, the ad hoc network will be started .

2. softbus\_bus\_center.h： Networking module header file , Support to obtain equipment information in the network API as follows ：

3. session.h： Connect / Transfer module header file , Support the creation of session And data transfer API as follows ：

various API See the header file description for parameters .

Application example

1. Write client program

Writing client programs depends on Embedded Version released SDK, Follow these steps SDK Preparation for environmental use .

1.1 install SDK

perform SDK Self extracting installation script

```bashsh openeuler-glibc-x86_64-openeuler-image-aarch64-qemu-aarch64-toolchain-22.03.sh ```

Enter the installation path of the tool chain according to the prompt , The default path is /opt/openeuler//; If we do not set up , Then install according to the default path ; You can also configure relative path or absolute path .

Examples are as follows ：

```bashsh ./openeuler-glibc-x86_64-openeuler-image-armv7a-qemu-arm-toolchain-22.03.sh``openEuler embedded(openEuler Embedded Reference Distro) SDK installer version 22.03================================================================Enter target directory for SDK (default: /opt/openeuler/22.03): sdkYou are about to install the SDK to "/usr1/openeuler/sdk". Proceed [Y/n]? yExtracting SDK...............................................doneSetting it up...SDK has been successfully set up and is ready to be used.Each time you wish to use the SDK in a new shell session, you need to source the environment setup script e.g.. /usr1/openeuler/sdk/environment-setup-armv7a-openeuler-linux-gnueabi ```

1.2 Set up SDK environment variable

The execution of the previous step is over, and finally it has been printed source command , Can run .

```bash. /usr1/openeuler/myfiles/sdk/environment-setup-armv7a-openeuler-linux-gnueabi```

1.3 Check whether the installation is successful

Run the following command , Check whether the installation is successful 、 Environment setting succeeded .

```basharm-openeuler-linux-gnueabi-gcc -v```

Next write the client program .

      Create a main.c file , Source code is as follows ：

```c    #include "dsoftbus/softbus_bus_center.h"    #include <stdio.h>    #include <stdlib.h>    int main(void){        int32_t infoNum = 10;        NodeBasicInfo **testInfo = malloc(sizeof(NodeBasicInfo *) * infoNum);        int ret = GetAllNodeDeviceInfo("testClient", testInfo, &infoNum);        if (ret != 0) {            printf("Get node device info fail.\n");            return 0;        }        printf("Get node num: %d\n", infoNum);        for (int i = 0; i < infoNum; i++) {            printf("\t networkId: %s, deviceName: %s, deviceTypeId: %d\n",            testInfo[i]->networkId,            testInfo[i]->deviceName,            testInfo[i]->deviceTypeId);        }        for (int i = 0; i < infoNum; i++) {            FreeNodeInfo(testInfo[i]);        }        free(testInfo);        testInfo = NULL;
        return 0;    }```

Create a `CMakeLists.txt` file , Source code is as follows ：

```bashproject(dsoftbus_hello C)add_executable(dsoftbus_hello main.c)target_link_libraries(dsoftbus_hello dsoftbus_bus_center_service_sdk.z)```

Compile client

 ```bashmkdir buildcd buildcmake ..make```

After compilation, you will get `dsoftbus_hello`.

2. structure QEMU Networking environment

stay host Create a bridge in br0

 ```bashbrctl addbr br0```

start-up qemu1

```bashqemu-system-aarch64 -M virt-4.0 -m 1G -cpu cortex-a57 -nographic -kernel zImage -initrd <openeuler-image-qemu-xxx.cpio.gz> -device virtio-net-device,netdev=tap0,mac=52:54:00:12:34:56 -netdev bridge,id=tap0```

Be careful

If the following error prompt appears during the first run ：

```bashfailed to parse default acl file `/usr/local/libexec/../etc/qemu/bridge.conf'qemu-system-aarch64: bridge helper failed ```

You need to add “allow br0”

```bashecho "allow br0" > /usr/local/libexec/../etc/qemu/bridge.conf```

start-up qemu2

```bashqemu-system-aarch64 -M virt-4.0 -m 1G -cpu cortex-a57 -nographic -kernel zImage -initrd openeuler-image-qemu-aarch64-20220331025547.rootfs.cpio.gz  -device virtio-net-device,netdev=tap1,mac=52:54:00:12:34:78 -netdev bridge,id=tap1```

Be careful

qemu1 And qemu2 Of mac The address needs to be configured with different values .

To configure IP

 To configure host Bridge address of ```bashifconfig br0 192.168.10.1 up```
 To configure qemu1 Network address of ```bashifconfig eth0 192.168.10.2```
 To configure qemu2 Network address of ```bashifconfig eth0 192.168.10.3```

Respectively in host、qemu1、qemu2 Use ping To test , Make sure qemu1 Sure ping through qemu2.

3. Start the distributed soft bus

 stay qemu1 and qemu2 Start the server of the distributed soft bus 
```bashsoftbus_server_main >log.file &```
 Distribute the compiled client to qemu1 and qemu2 In the root directory of 
```bashscp dsoftbus_hello [email protected]192.168.10.2:/scp dsoftbus_hello [email protected]192.168.10.3:/```

Respectively in qemu1 and qemu2 Run in the root directory of `dsoftbus_hello`, You'll get the following output ：

qemu1
```bash[LNN]NodeStateCbCount is 10[LNN]BusCenterClientInit init OK![DISC]Init success[TRAN]init tcp direct channel success.[TRAN]init succ[COMM]softbus server register service success!
[COMM]softbus sdk frame init success.Get node num: 1networkId: 714373d691265f9a736442c01459ba39236642c743a71750bb63eb73cde24f5f, deviceName: UNKNOWN, deviceTypeId: 0```
qemu2
```bash[LNN]NodeStateCbCount is 10[LNN]BusCenterClientInit init OK![DISC]Init success[TRAN]init tcp direct channel success.[TRAN]init succ[COMM]softbus server register service success!
[COMM]softbus sdk frame init success.Get node num: 1networkId: eaf591f64bab3c20304ed3d3ff4fe1d878a0fd60bf8c85c96e8a8430d81e4076,deviceName: UNKNOWN, deviceTypeId: 0```

qemu1 and qemu2 The basic information of the other party's equipment found is output respectively .

Compilation guide

Compilation depends on Embedded Container image of version release , Please refer to the container construction guide for container environment preparation .

Container build guide link ：

<https://docs.openeuler.org/zh/docs/22.03_LTS/docs/Embedded/ Container building instructions .html>

1. The warehouse where the script is downloaded （ For example, download to `src/yocto-meta-openeuler` Under the table of contents ）

```bashgit clone https://gitee.com/openeuler/yocto-meta-openeuler.git -b openEuler-22.03-LTS -v src/yocto-meta-openeuler```

2. Execute the download script

  Download the latest soft bus code :```bashsh src/yocto-meta-openeuler/scripts/download_code.sh dsoftbus```

The code is downloaded to and by default `yocto-meta-openeuler` Same level path , If you need to modify the soft bus or its dependent module code, you can find it in the corresponding path `dsoftbus/_standard` and `yocto-embedded-tools` Modify the warehouse accordingly .

3. Compiling scripts

 Compile the latest soft bus code :```bashsh src/yocto-meta-openeuler/scripts/compile.sh dsoftbus```

The compilation working directory is named dsoftbus/_build, The directory name of the compiled artifacts is dsoftbus/_output, Both default to yocto-meta-openeuler At the same level path .

- Restriction constraint  -

1. Only supported under LAN coap Find out .WIFI/BLE And other functions will continue to be supported in subsequent versions .

2. At present IPC、SN The dependent modules of soft bus such as No. are examples , Only dual device node deployment is supported ,client-server One to one deployment capability . Looking forward to the follow-up with community partners , These dependent modules are instantiated together according to the actual scenario .

-  Pay attention to our  -

Embedded Already in openEuler Community open source . A series of topics will be shared , If you are right about Embedded The construction of , Application is interested in , Welcome to watch and join .

Project address ：

<https://gitee.com/openeuler/yocto-meta-openeuler>

Welcome to star、fork, Get involved in community development , Contribute more .

-  Enter the communication group  -

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