Wanted to share a few updates and tweaks to the original Get Interface name by hardware address code. The below is broken up in to functions to help with code re-useability .
If also prints all interface names and hardware address when no command line argument are present.
package main
import (
"net"
"fmt"
"os"
"strings"
)
// Use the net library to return all Interfaces
// and capture any errors.
func getInterfaces() ([]net.Interface) {
interfaces, err := net.Interfaces()
if err != nil {
panic("Unable to get interfaces.")
}
return interfaces
}
// Use the net library to get Interface by Index number
// and capture any errors.
func getInterfaceByIndex(index int) (*net.Interface) {
inter, err := net.InterfaceByIndex(index)
if err != nil {
panic("Unable to get interface by index")
}
return inter
}
// Use the net library to get Interface by Name
// and capture any errors
func getInterfaceByName(name string) (*net.Interface) {
inter, err := net.InterfaceByName(name)
if err != nil {
panic("Unable to get interface by name")
}
return inter
}
// Using the net library we will loop over all interfaces
// looking for the interface with matching mac_address.
func getInterfaceByHardwareAddress(mac string) (net.Interface) {
interfaces := getInterfaces()
for _, inter := range interfaces {
if strings.ToUpper(mac) == strings.ToUpper(inter.HardwareAddr.String()) {
return inter
}
}
panic("Unable to find interface with Hardware Address.")
}
func main() {
args := os.Args
// If we have only 2 arguments we will assume the
// second is mac_address.
if len(args) == 2 {
mac_address := args[1]
inter := getInterfaceByHardwareAddress(mac_address)
fmt.Println(inter.Name)
// If no arguments were passed in lets just return
// a list of all interface names and hardware addresses.
} else if len(args) == 1 {
for _, inter := range getInterfaces() {
fmt.Println(inter.Name, inter.HardwareAddr)
}
// If the number of command line arguments are not expected
// lets panic and explain why.
} else {
panic("We require one (mac_address) or no command line arguments.")
}
}
Usage looks something like this:
$ go build get_interface.go
$ ./get_interface
lo
en0 12:34:56:68:90:00
$ ./get_interface 12:34:56:68:90:00
en0