MAC Address printing

Question

This is a code that gets some info about network the problem is when it prints the MAC address it prints it sometime normally and sometime with fff\'s like 00:21:84:a2:12:88

Answer 1

Although there is already an accepted answer here, there is a better solution in netinet/ether.h.

Given that Mac addresses are typically stored in u_int8_t types, as in the ether_addr struct:

You can simply do this:

printf("Mac Address: %s", ether_ntoa((struct ether_addr*)ar->sa));

in my Case ar is something that looks like this:

struct {
   u_int8_t sa[6];
}

You can easily copy this into another buffer with something like asprintf:

char *formatted_mac_address;
asprintf(formatted_mac_address, "Mac Address: %s", ether_ntoa((struct ether_addr*)ar->sa));

If you don't have a struct as I do, you can also just use the address of any u_int8_t in place of ar->sa.

Appropriate headers/etc should be pulled in, but that's going to look a lot neater than the accepted solution here.