Example of getting the IP and netmask of an interface with Golang

get-interface-ip-mask.go

package main

import (
    "fmt"
    "net"
    "os"
)

func main() {
    mgmtInterface, err := net.InterfaceByName("ens160")
    if err != nil {
        fmt.Println("Unable to find interface")
        os.Exit(-1)
    }

    addrs, err := mgmtInterface.Addrs()
    if err != nil {
        fmt.Println("Interface has no address")
        os.Exit(-1)
    }
    for _, addr := range addrs {
        var ip net.IP
        var mask net.IPMask
        switch v := addr.(type) {
        case *net.IPNet:
            ip = v.IP
            mask = v.Mask
        case *net.IPAddr:
            ip = v.IP
            mask = ip.DefaultMask()
        }
        if ip == nil {
            continue
        }
        ip = ip.To4()
        if ip == nil {
            continue
        }
        cleanMask := fmt.Sprintf("%d.%d.%d.%d", mask[0], mask[1], mask[2], mask[3])
        fmt.Println(ip, cleanMask)
    }
}