/*
 * $Id: getlladdr.c,v 1.1.1.1 2003/06/25 10:52:55 fjoe Exp $
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/sysctl.h>

#include <net/if.h>
#include <net/if_var.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/route.h>

#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void
getlladdr(const char *if_name)
{
	static int initialized = 0;
	static size_t needed;
	static char *buf;

	int found = 0;
	char *lim, *next;

	if (!initialized) {
		int mib[6];

		mib[0] = CTL_NET;
		mib[1] = PF_ROUTE;
		mib[2] = 0;
		mib[3] = AF_LINK;	/* address family */
		mib[4] = NET_RT_IFLIST;
		mib[5] = 0;

		if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
			errx(1, "iflist-sysctl-estimate");
		if ((buf = malloc(needed)) == NULL)
			errx(1, "malloc");
		if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0)
			errx(1, "actual retrieval of interface table");
		initialized = 1;
	}

	lim = buf + needed;
	next = buf;
	while (next < lim) {
		struct sockaddr_dl *sdl;
		struct if_msghdr *ifm;

		ifm = (struct if_msghdr *)next;
		if (ifm->ifm_type == RTM_IFINFO)
			sdl = (struct sockaddr_dl *)(ifm + 1);
		else {
			fprintf(stderr, "out of sync parsing NET_RT_IFLIST\n");
			fprintf(stderr, "expected %d, got %d\n", RTM_IFINFO,
				ifm->ifm_type);
			fprintf(stderr, "msglen = %d\n", ifm->ifm_msglen);
			fprintf(stderr, "buf:%p, next:%p, lim:%p\n", buf, next,
				lim);
			exit (1);
		}
		next += ifm->ifm_msglen;

		if (if_name == NULL ||
		    !strncmp(sdl->sdl_data, if_name, sdl->sdl_nlen)) {
			if (sdl->sdl_alen > 0) {
				int i;

				printf("%.*s: ", sdl->sdl_nlen, sdl->sdl_data);
				for (i = 0; i < sdl->sdl_alen; i++) {
					if (i > 0)
						putchar(':');
					printf("%02x", (u_int8_t) sdl->sdl_data[sdl->sdl_nlen + i]);
				}
				putchar('\n');
			} else {
				printf("%.*s: <no lladdr>\n",
				       sdl->sdl_nlen, sdl->sdl_data);
			}

			if (if_name != NULL) {
				found = 1;
				break;
			}
		}
	}

	if (if_name != NULL && !found)
		printf("%s: not found\n", if_name);
}

int
main(int argc, char *argv[])
{
	if (argc < 2)
		getlladdr(NULL);
	for (argv++; *argv; argv++)
		getlladdr(*argv);
	return 0;
}