SIOCGIFCONF return only loopback interface

I want to get all network interfaces names present on the system. For system portability (Android included) I decided to write a method that performs this task using ioctl because I think (probably wrongly) that ioctl is one of the best for this task. So I wrote this code

struct ifconf contr_req;
contr_req.ifc_ifcu.ifcu_req = NULL;
if(ioctl(sock,SIOCGIFCONF,&contr_req) < 0)
    return NULL;


contr_req.ifc_ifcu.ifcu_buf = malloc(contr_req.ifc_len);
register int len = contr_req.ifc_len/sizeof(struct ifreq);
char **names = malloc(sizeof(char*)*len);

if(ioctl(sock,SIOCGIFCONF,&contr_req) < 0)
    return NULL;

struct ifreq *ini;
for(int i = 0;i < len; i++){
    ini = contr_req.ifc_ifcu.ifcu_req +
                sizeof(struct ifreq)*i;

    register name_len = strlen(ini->ifr_ifrn.ifrn_name)+1;
    names[i] = malloc(name_len);
    memset(names[i],0,name_len);
    memcpy(names[i],ini->ifr_ifrn.ifrn_name,name_len-1);
}

return names;

But the problem is, that it returns only the loopback interface. Can anyone explain where is the mistake or if there is another ioctl entry to return all interfaces names on the system?

(I don’t want to use getifaddr or if_nameindex but ioctl.)

Answer

Finally i discovered that SIOCGIFCONF returns only the interfaces that are connected.

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Answer