UDP Client
Overview
The application creates a UDP socket and attempts to connect to the server using a predefined IP address and port number. Once the connection is successfully established, the application sends a message and waits for a response. After receiving the server’s reply, the application prints the received response as ASCII text, waits for 2 seconds, and sends another message. If there is no response from the server, the application waits for 10 seconds, prints “recvfrom failed: errno 11,” and resends the message. There are many host-side tools available to interact with UDP/TCP servers/clients. Only the netcat tool is used here as an example for send and receive many kinds of packets. Note: please replace “192.168.3.220 3333” with desired IPV4/IPV6 address and port number in the following command.
In addition, you can borrow some public servers to test the UDP connection function of the device. You can use the HeZhou TCP/UDP web testing tool Note that this server is not operated by Lianshengde and there may be scenarios where the service is unavailable. Users can search for available servers themselves to try.
Send UDP packet via netcat
echo "hello" | nc -w1 -u 192.168.3.220 3333
Receive UDP packet via netcat
echo "hello" | nc -w1 -u 192.168.3.220 3333
UDP server using netcat
nc -u -l 192.168.3.220 3333
Requirements
A working AP is required.
Configure WiFi SSID and WiFi Password in menuconfig.
Configure the IPV4 Address and Port in menuconfig.
Building and Flashing
Example Location： examples/network/sockets/udp_client
compile, burn, and more, see: Quick Start Guide
Running Result
Upon successful execution, it will output the following logs
[I] (3502) wm_nm_core: sta got ip: 192.168.3.82
[I] (3690) udp client: wifi station start success, network is ready!
[I] (3690) udp client: Socket created, sending to 192.168.3.72:3333
[I] (3690) udp client: Message sent
[E] (13692) udp client: recvfrom failed: errno 11
[E] (13692) udp client: Shutting down socket and restarting...
[I] (13692) udp client: Socket created, sending to 192.168.3.72:3333
[I] (13692) udp client: Message sent
[I] (17922) udp client: Received 8 bytes from 192.168.3.72:
[I] (17922) udp client: hello123
[I] (19922) udp client: Message sent