Openeuler 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 .

openeuler ~ # 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 ：

• discovery_service.h： Found module header file , Support application active detection and release API as follows ：

Among them, the service capacity passes

g\_capabilityMap

To define an array , If you want to add new capabilities, you need to customize and modify the array , And recompile the soft bus server and client programs to take effect .

• softbus_bus_center.h： Networking module header file , Support to obtain equipment information in the network API as follows ：

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

Application example

Use QEMU Deploy distributed soft bus , Write client program , Enable it to list all found device information .

• Write client program

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

• install SDK

perform SDK Self extracting installation script

sh 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/<openeuler version>/

; 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 ：

sh ./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): sdk
You are about to install the SDK to "/usr1/openeuler/sdk". Proceed [Y/n]? y
Extracting SDK...............................................done
Setting 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

• Set up SDK environment variable

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

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

• Check whether the installation is successful

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

arm-openeuler-linux-gnueabi-gcc -v

Next write the client program .

Create a

main.c

file , Source code is as follows ：

#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(&quot;testClient&quot;, testInfo, &infoNum);
 if (ret != 0) {
 printf(&quot;Get node device info fail.\n&quot;);
 return 0;
 }
 printf(&quot;Get node num: %d\n&quot;, infoNum);
 for (int i = 0; i < infoNum; i++) {
 printf(&quot;\t networkId: %s, deviceName: %s, deviceTypeId: %d\n&quot;,
 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 ：

project(dsoftbus_hello C)
add_executable(dsoftbus_hello main.c)
target_link_libraries(dsoftbus_hello dsoftbus_bus_center_service_sdk.z)

Compile client

mkdir build
cd build
cmake ..
make

After compilation, you will get

dsoftbus_hello

.

• structure QEMU Networking environment

stay host Create a bridge in br0

brctl addbr br0

start-up qemu1

qemu-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 ：

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

You need to add “allow br0”

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

start-up qemu2

qemu-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

ifconfig br0 192.168.10.1 up

To configure IP

To configure host Bridge address of

ifconfig eth0 192.168.10.2

To configure qemu2 Network address of

ifconfig eth0 192.168.10.3

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

• Start the distributed soft bus

stay qemu1 and qemu2 Start the server of the distributed soft bus

softbus_server_main >log.file &

Distribute the compiled client to qemu1 and qemu2 In the root directory of

scp dsoftbus_hello [email protected]:/
scp dsoftbus_hello [email protected]:/

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

qemu1

[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: 1
 networkId: 714373d691265f9a736442c01459ba39236642c743a71750bb63eb73cde24f5f, deviceName: UNKNOWN, deviceTypeId: 0


qemu2

[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: 1
 networkId: 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

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

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

• Execute the download script

Download the latest soft bus code :

sh 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 :

sh 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

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

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, Participate in community development and contribution .

If you are interested in embedded applications , Welcome to join  openEuler Embedded&Yocto SIG , Discuss  Embedded  and  Yocto  And other related technologies .