How to set the IP address of the network interface in golang

Golang is an efficient, concise and fast-developing programming language with many popular features. One of them is its network programming capabilities. Through its network programming package, we can realize the connection of TCP/IP protocol and UDP protocol. At the same time, you can also use Golang to set the network card IP address, which is an important function of network programming.

In Linux systems, we often need to use the command line to configure network interfaces. Correspondingly, when writing network applications using Golang, we can use similar commands to set the network interface. In this article, we will introduce how to set the IP address of a network interface using Golang.

1. Import the required packages

When writing a Golang program, the first step is to import the required packages. In this example, we will need to import the "net" package and the "os/exec" package because they contain the functions we need to use. Use the following command to import the required packages:

import (
    "net"
    "os/exec"
)

2. Get the network interface

Before setting the IP address of the network interface, we need to obtain the relevant information of the network interface to be set. We can use the following code to get the information of the network interface:

iface, err := net.InterfaceByName("eth0")
if err != nil {
    log.Fatalf("Failed to get interface: %v", err)
}

Here, we get the information of the eth0 network interface and store it in the iface variable. If we don't find the network interface, an error will be thrown here.

3. Generate ip command

By running the specified command line command, we can achieve the purpose of setting the IP address of the network interface. On Linux systems, we can use the ip command to set the IP address by executing the following command:

ip addr add 192.168.0.100/24 dev eth0

Here, we use the ip command to assign an IP address of 192.168.0.100 to the eth0 interface and subtitle it. The netmask is set to a 24-bit mask (i.e. 255.255.255.0). To generate this command we can use the following code:

cmd := exec.Command(
    "ip", "addr", "add", "192.168.0.100/24", "dev", iface.Name,
)

This command will be executed in our Golang program. After completing the command, we will successfully set a new IP address for the eth0 interface.

4. Set IP address

With the generated command, we can now start setting the IP address in Golang. We can use the following code to execute the previously generated command:

if err := cmd.Run(); err != nil {
    log.Fatalf("Failed to set ip address: %v", err)
} else {
    log.Println("IP address set successfully")
}

Here, we use the "cmd.Run()" method to execute the previously generated ip command. If an error occurs when executing the command, we will throw An error occurs and exits; if the command execution is successful, log information is output.

5. Test setting results

Does the IP address we set take effect? We can check if the new IP address has taken effect using the following code:

addrs, err := iface.Addrs()
if err != nil {
    log.Fatalf("Failed to get iface addresses: %v", err)
}

for _, addr := range addrs {
    if ipnet, ok := addr.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
        if ipnet.IP.To4() != nil {
            log.Printf("IP address is set to %v", ipnet.IP.String())
        }
    }
}

Here we retrieve all IP addresses on the eth0 interface and check if one has been set to the new IP address. If any setting is successful, we can see it from the log information.

Summary

In this article, we learned how to set the IP address of a network interface using Golang. We used the "net" package and the "os/exec" package, which contain the functions we need to use. We started with the network interface information, generated the ip command, used the generated command to set the IP address, and finally checked whether the new IP address took effect. Typically, this technology is a basic skill in network programming and is also very important for professional system administrators and network engineers.

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