Reading the HARDWARE ethernet address from a program?

[Matt Thomas]

In article <19290 at dime.cs.umass.edu> williams at cs.umass.edu writes:
>We have a need to obtain the hardware ethernet address within a program.
>We can obtain this address on a Sun using an ioctl call on /dev/nit
>([sun-spots program] getaddr.c ) Does anyone know how one could obtain the
>physical ethernet address in ultrix, in particular for the dec5000, MIPS
>based workstation?
>
>If this is not of general interest, you can email to ralf at aai.com.  I will
>also check for followups.
>
>Thanks for any help!
>
>Leo	leo at aai.com   leo%aai at uunet.uu.net   ...uunet!aai!leo

#include <stdio.h>			/* standard I/O */
#include <errno.h>			/* error numbers */
#include <time.h>			/* time definitions */
#include <sys/types.h>			/* system types */
#include <sys/socket.h>			/* socket stuff */
#include <sys/ioctl.h>			/* ioctls */
#include <net/if.h>			/* generic interface structs */

extern	char	*optarg;
extern	int	optind;
extern	char	*sys_errlist[];

main( argc, argv )
	int argc;
	char *argv[];
{
    struct ifdevea devea;
    struct ifreq *ifr, ifreqs[32];
    struct ifconf ifc;
    int s, i;

    bzero(&devea, sizeof(devea));

    /*  we need a socket -- any old socket will do.  */
    s = socket(AF_UNIX, SOCK_DGRAM, 0);
    if (s < 0) {
	perror("socket");
	exit(1);
    }

    ifc.ifc_req = ifreqs;
    ifc.ifc_len = sizeof(ifreqs);
    if (ioctl(s, SIOCGIFCONF, &ifc) < 0) {
	perror("siocgifconf");
	exit(1);
    }

    for (ifr = ifreqs; ifc.ifc_len > 0; ifr++, ifc.ifc_len -= sizeof(*ifr)) {
	if (strcmp(devea.ifr_name, ifr->ifr_name)) {
	    (void) strcpy(devea.ifr_name, ifr->ifr_name);
	    /* read the address of the interface */
	    if (ioctl(s, SIOCRPHYSADDR, &devea) < 0)  {
		/* error? */
		if  (errno != EOPNOTSUPP && errno |= EINVAL) {
		    /* unexpected error */
		    perror(devea.ifr_name);
		}
		continue;
	    }
	    printf("%s: ", devea.ifr_name);
	    printf("current = %02x-%02x-%02x-%02x-%02x-%02x, ",
		devea.current_pa[0], devea.current_pa[1], devea.current_pa[2], 
		devea.current_pa[3], devea.current_pa[4], devea.current_pa[5]
		);
	    printf("default = %02x-%02x-%02x-%02x-%02x-%02x\n",
		devea.default_pa[0], devea.default_pa[1], devea.default_pa[2], 
		devea.default_pa[3], devea.default_pa[4], devea.default_pa[5]
		);
	}
    }
}
Matt Thomas                     Internet:   thomas at wrl.dec.com
DECnet-ULTRIX Development       UUCP:       ...!decwrl!thomas
Digital Equipment Corporation   Disclaimer: This message reflects my own
Littleton, MA                               warped views, etc.