Getting Ethernet interface speed on Linux using Go via cgo

ifspace.go

package main

/*

#include <stdio.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <linux/sockios.h>
#include <linux/if.h>
#include <linux/ethtool.h>
#include <string.h>
#include <stdlib.h>

int get_interface_speed(char *ifname){
	int sock;
    struct ifreq ifr;
	struct ethtool_cmd edata;
	int rc;
	sock = socket(AF_INET, SOCK_STREAM, 0);
	// string copy first argument into struct
	strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
	ifr.ifr_data = &edata;
    // set some global options from ethtool API
	edata.cmd = ETHTOOL_GSET;
    // issue ioctl
	rc = ioctl(sock, SIOCETHTOOL, &ifr);
	if (rc < 0) {
		perror("ioctl");        // lets not error out here
		// make sure to zero out speed
		return 0;
	}
    return edata.speed;
}

*/
import "C"

import (
	"fmt"
	"unsafe"
)

func main() {
	ifname := []byte("eth0\x00")
	sp := C.get_interface_speed((*C.char)(unsafe.Pointer(&ifname[0])))
	fmt.Println(sp)
}