golang modify local ip

When writing applications, we often need to use local IP addresses, and in some cases, we may need to modify the local IP address. How to achieve this? This article will introduce how to modify the local IP address using Go language.

Go language is an emerging programming language. It has the efficiency and portability of C language and the safety and ease of use of Java language. Therefore, it is becoming more and more popular among programmers. .

In Go language, we can use the net package to manage local IP addresses. Specifically, the net package provides some functions that can be used to find local IP addresses, add new IP addresses, modify IP addresses, and other operations.

The following are the steps to use Go language to modify the local IP address:

Step 1: Import the net package

Before using the net package, we need to import the net package into the program , as shown below:

import "net"

Step 2: Obtain the local IP address

Before modifying the local IP address, we need to obtain the local IP address first. You can use the functions provided by the net package to achieve this function. Among them, the net.InterfaceAddrs() function can return the IP address list of all network cards. We can find the IP address of the currently used network card in the list. The following is a sample code to obtain the local IP address:

addrs, err := net.InterfaceAddrs()
if err != nil {
    fmt.Println(err)
}
for _, addr := range addrs {
    if ipnet, ok := addr.(*net.IPNet); ok && !ipnet.IP.IsLoopback() && ipnet.IP.To4() != nil {
        fmt.Println(ipnet.IP.String())
    }
}

The above code traverses all network cards and returns the network card address that is not a loopback address and is IPv4.

Step 3: Modify the local IP address

After finding the local IP address, we can use the net.InterfaceAddrs() function to obtain the IP address of the currently used network card, and modify it. The following is a sample code to modify the local IP address:

iface, err := net.InterfaceByName("eth0") // 指定使用eth0口
if err != nil {
    fmt.Println(err)
}
ip, _, err := net.ParseCIDR("192.168.1.101/24") // 指定IP地址和掩码
if err != nil {
    fmt.Println(err)
}
addr := &net.IPNet{
    IP:   ip,
    Mask: net.IPv4Mask(255, 255, 255, 0),
}
err = netlink.AddrReplace(&netlink.Addr{
    IPNet: addr,
    Label: iface.Name,
})
if err != nil {
    fmt.Println(err)
}

In the above code, we use the net.InterfaceByName() function to find the network card, and then use net.ParseCIDR()The function parses the IP address and mask and creates a new IP address. Finally, we use the netlink.AddrReplace() function to apply the new address to the network card.

It should be noted that to modify the local IP address, you need to run it as the root user, otherwise an error will be reported. Therefore, when executing this program on a Linux platform, you need to use the sudo command or run it as the root user.

The above is how to modify the local IP address using Go language. Through the above steps, we can easily modify the local IP address to adapt to different network environments.

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