1. AliOS Things Wi-Fi networking background

Connecting to a Wi-Fi network is the first step for most IoT devices to connect to the Internet.

Access to Wi-Fi generally requires two stages: network distribution and network connection.

1.1 Introduction to Netmgr

The Netmgr module introduced in this article abstracts the Wi-Fi-driven network distribution and networking capabilities to facilitate IoT devices to quickly access the network and connect to the cloud.

Wi-Fi devices need to be connected to Wi-Fi hotspots (Wi-Fi AP) before they can communicate with other devices based on IP. We call the step of Wi-Fi devices obtaining the SSID/password of Wi-Fi hotspots as Wi-Fi. Fi distribution network. For mobile phones/computers/tablets, users can enter the SSID/password of the Wi-Fi hotspot through the keyboard or touch screen. But for IoT devices with no keyboard and no touch screen, how to obtain the SSID/password of the Wi-Fi hotspot is the first key step to realize device network management.

1.2 Distribution network

Briefly introduce the following two network distribution methods:

1. Zero configuration : A network configuration solution that does not require users to input hotspot information. It allows a device connected to the Internet hotspot to send the hotspot's SSID/password to the device to be configured.

2. One-click network configuration : The mobile phone APP packs the corresponding information into a specific area of the 802.11 data packet and sends it to the surrounding environment; the Wi-Fi module of the smart device is in the Promiscuous Model and monitors all messages in the network , Until the required information is parsed (the two parties agreed on the data format before).

For more information about the distribution network, please refer to the article:

N ways of Wi-Fi Internet of Things device network distribution

1.3, network connection

Either way, the ultimate goal is to get the SSID/PASSWORD, connect to the AP, and access the network.

The terminal device needs to go through three stages to successfully connect to Wi-Fi:

1) Scanning phase (SCAN);

2) Authentication phase (Authentication);

3) Association (Association).

After the association is successful, the terminal device initiates a DHCP request or uses a static IP address, which means that the network is successfully connected.

2. Important Netmgr API

Netmgr provides a set of API support to facilitate users to quickly access AP.

2.1、netmgr_init

Initialize the netmgr module

Function prototype

int netmgr_init(void);

parameter name	Parameter Description	Parameter example
`无`	no	no

Return parameter

0, success

Less than 0, failure

2.2 、 netmgr_deinit

Uninitialize netmgr

Function prototype

void netmgr_deinit(void);

parameter list

parameter name	Parameter Description	Parameter example
`无`	no	no

Return parameter

2.3、netmgr_start

Start netmgr

Function prototype

int netmgr_start(bool autoconfig);

parameter list

parameter name	Parameter Description	Parameter example
`autoconfig`	Whether to automatically initiate Wi-Fi connection	no

Return parameter

0, success

Less than 0, failure

note:

When the parameter autoconfig is true, the automatic Wi-Fi connection function is enabled. If the device has a record of successfully connecting to an AP, it will automatically connect to the SSID and Password in the record of the successfully connected AP.

If the device does not successfully connect to the AP, it will not automatically initiate a network connection. When the parameter autoconfig is false, the function of automatically connecting to the AP is disabled and the AP will not be connected.

2.4、netmgr_connect

Connect Network

Function prototype

int32_t netmgr_connect(const char *ssid, const uint8_t *password, uint32_t timeout);

parameter list

parameter name	Parameter Description	Parameter example
`ssid`	Wi-Fi SSID	to
password	password	123456
timeout	Timeout (milliseconds)	100

Return parameter

0, success

Other, fail

2.5、netmgr_stats

Get network statistics, now mainly IP address.

Function prototype

void netmgr_stats(int32_t interface, netmgr_stats_t *stats);

parameter list

parameter name	Parameter Description	Parameter example
`interface`	NIC name	INTERFACE_WIFI
stats	Network card statistics	/

Return parameter

3. API usage example

3.1, direct connection

#include "netmgr.h"
#include "aos/yloop.h"

static void wifi_service_event(input_event_t *event, void *priv_data)
{
    if (event->type != EV_WIFI) {
        return;
    }

    if (event->code != CODE_WIFI_ON_GOT_IP) {
        return;
    }
    
    // add application start logic here
}

void start_netmgr(void) {
    netmgr_init();
    aos_register_event_filter(EV_WIFI, wifi_service_event, NULL);
    netmgr_start(false);
    netmgr_connect("Test_WiFi", "123456", 10000);
}

3.2. Use history to connect to the Internet

#include "netmgr.h"
#include "aos/yloop.h"

static void wifi_service_event(input_event_t *event, void *priv_data)
{
    if (event->type != EV_WIFI) {
        return;
    }

    if (event->code != CODE_WIFI_ON_GOT_IP) {
        return;
    }
    
    // add application start logic here
}

void start_netmgr(void) {
    netmgr_init();
    aos_register_event_filter(EV_WIFI, wifi_service_event, NULL);
    netmgr_start(true);
}

3.3, use netmgr example

In the above example, a wifi_service_event event is registered to monitor the event. When the type is EV_WIFI and the code is CODE_WIFI_ON_GOT_IP, it means that the IP address is successfully obtained.

Add the start_netmgr function in the above example to the file application/example/helloworld_demo / appdemo.c.

Note that two header files, netmgr.h and aos/yloop.h, need to be added at the same time.

int application_start(int argc, char *argv[])
     int count = 0;
     printf("nano entry here!\r\n");
 
     start_netmgr();

     while(1) {
        printf("hello world! count %d \r\n", count++);

        aos_msleep(1000);
    };
}

3.4, add netmgr module

在application/example/helloworld_demo/Config.in里增加"select AOS_COMP_NETMGR if !AOS_CREATE_PROJECT"

config AOS_APP_HELLOWORLD_DEMO
    bool "Helloworld Demo"
    select AOS_COMP_OSAL_AOS if !AOS_CREATE_PROJECT
    select AOS_COMP_NETMGR if !AOS_CREATE_PROJECT
    help
        helloworld demo

if AOS_APP_HELLOWORLD_DEMO
# Configurations for app helloworld_demo
config SYSINFO_APP_VERSION
    string "Firmware Version"
    default "app-1.0.0-20200214.140831"
    help
        application main firmware version
endif

4. Netmgr command

4.1. Command introduction

Supports Wi-Fi connection-related operations using commands, such as:

-Read/write/delete the stored connection information

-Print the information of all APs in the current network,

-Connect AP, disconnect AP

-Query network status, etc.

Command Line	Description
netmgr -t wifi -i	initialization
netmgr -t wifi -a [0/1]	Set whether to automatically reconnect. 0, do not automatically reconnect; 1, automatically reconnect.
netmgr -t wifi -b [0/1]	Whether to save historical connection records. 0, do not save historical connection records. 1. Save historical connection records.
netmgr -t wifi -c [ssid] [password]	Use ssid password to connect to the Internet
netmgr -t wifi -e	Disconnect Wi-Fi connection
netmgr -t wifi -w [wifi_config]	Write Wi-Fi configuration files. wifi_config format, such as network={\\nssid=\"aos\"\\npassword=\"123456\"\\nchannel=\"0\"\\n}\\n
netmgr -t wifi -r	Read Wi-Fi profile
netmgr -t wifi -d	Delete Wi-Fi profile
netmgr -t wifi -p	Print current network status
netmgr -t wifi -s	Print AP information on the current network

4.2. Command example

Use the following command to quickly connect to the AP whose SSID is "aos" and password is "123456".

netmgr -t wifi -i
netmgr -t wifi -b 1
netmgr -t wifi -a 1
netmgr -t wifi -c aos 123456

You can also write the configuration commands manually, and use the following commands to connect to the network. Among them, if the channel information of the AP cannot be determined, use 0 to scan the entire network segment.

netmgr -t wifi -i
netmgr -t wifi -w network={\\nssid=\"aos\"\\npassword=\"123456\"\\nchannel=\"0\"\\n}\\n
netmgr -t a 1

4.3, Netmgr command use case

Build smart home applications based on HaaS 100

If you want to learn more about the above functions, welcome to visit the AliOS Things Github project homepage and use the latest open source version of AliOS Things.

More functions will be launched in the follow-up open source version of AliOS Things.

5. Developer technical support

If you need more technical support, you can join the Dingding Developer Group

For more technology and solution introduction, please visit the Aliyun AIoT homepage https://iot.aliyun.com/

AliOS Things Wi-Fi connected to those things

1. AliOS Things Wi-Fi networking background

1.1 Introduction to Netmgr

1.2 Distribution network

1.3, network connection

2. Important Netmgr API

2.1、netmgr_init

2.2 、 netmgr_deinit

2.3、netmgr_start

2.4、netmgr_connect

2.5、netmgr_stats

3. API usage example

3.1, direct connection

3.2. Use history to connect to the Internet

3.3, use netmgr example

3.4, add netmgr module

4. Netmgr command

4.1. Command introduction

4.2. Command example

4.3, Netmgr command use case

5. Developer technical support

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