If there is only one NIC in the system that is up and running, the

interface specifier on the command line can be ommited.

Besides of this, the bpf is being reused for each machine
that has to be woken up.

Submitted by:	Marc Balmer <marc@msys.ch>

usr.sbin/wake/wake.8

@@ -1,7 +1,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.\" Copyright (c) 2009 Marc Balmer <marc@msys.ch>
+.\" Copyright (c) 2009, 2010 Marc Balmer <marc@msys.ch>
 .\"
 .\" Permission to use, copy, modify, and distribute this software for any
 .\" purpose with or without fee is hereby granted, provided that the above
@@ -23,7 +23,7 @@
 .Nd send Wake on LAN frames to hosts on a local Ethernet network
 .Sh SYNOPSIS
 .Nm
-.Ar interface
+.Op Ar interface
 .Ar lladdr
 .Op Ar lladdr ...
 .Sh DESCRIPTION
@@ -37,21 +37,27 @@ and can be used to power on machines from a remote system without
 having physical access to them.
 .Pp
 .Ar interface
-is a network interface of the local machine.
+is an Ethernet interface of the local machine and is used to send the
+Wake on LAN frames over it.
+If there is only one Ethernet device available that is up and running, then the
+.Ar interface
+argument can be omitted.
 .Ar lladdr
-are the link layer addresses of the remote machines
+is the link layer address of the remote machine.
-and can be specified as the actual hardware address
+This can be specified as the actual hardware address
 (six hexadecimal numbers separated by colons)
-or a hostname entry in
+or as a hostname entry in
 .Pa /etc/ethers .
-Link layer addresses can be determined and set on
+.Nm
-.Fx
+accepts multiple
-machines using
+.Ar lladdr
+addresses.
+Link layer addresses can be determined and set using
 .Xr ifconfig 8 .
 .Sh FILES
 .Bl -tag -width "/etc/ethers" -compact
 .It /etc/ethers
-Ethernet host name database.
+Ethernet host name data base.
 .El
 .Sh SEE ALSO
 .Xr ethers 5 ,

usr.sbin/wake/wake.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2006, 2007, 2008, 2009 Marc Balmer <marc@msys.ch>
+ * Copyright (C) 2006, 2007, 2008, 2009, 2010 Marc Balmer <marc@msys.ch>
  * Copyright (C) 2000 Eugene M. Kim.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -32,11 +32,14 @@ __FBSDID("$FreeBSD$");
 #include <sys/time.h>
 #include <net/bpf.h>
 #include <net/if.h>
+#include <net/if_dl.h>
+#include <net/if_types.h>
 #include <netinet/in.h>
 #include <netinet/if_ether.h>
 
 #include <err.h>
 #include <fcntl.h>
+#include <ifaddrs.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -53,38 +56,29 @@ __FBSDID("$FreeBSD$");
 #endif
 
 static int	bind_if_to_bpf(char const *ifname, int bpf);
+static int	find_ether(char *dst, size_t len);
 static int	get_ether(char const *text, struct ether_addr *addr);
 static int	send_wakeup(int bpf, struct ether_addr const *addr);
 static void	usage(void);
-static int	wake(const char *iface, const char *host);
+static int	wake(int bpf, const char *host);
 
 static void
 usage(void)
 {
 
-	(void)fprintf(stderr, "usage: wake interface lladdr [lladdr ...]\n");
+	(void)fprintf(stderr, "usage: wake [interface] lladdr [lladdr ...]\n");
 	exit(1);
 }
 
 static int
-wake(const char *iface, const char *host)
+wake(int bpf, const char *host)
 {
 	struct ether_addr macaddr;
-	int bpf, res;
 
-	bpf = open(_PATH_BPF, O_RDWR);
+	if (get_ether(host, &macaddr) == -1)
-	if (bpf == -1) {
-		warn("no bpf");
 		return (-1);
-	}
+
-	if (bind_if_to_bpf(iface, bpf) == -1 ||
+	return send_wakeup(bpf, &macaddr);
-	    get_ether(host, &macaddr) == -1) {
-		(void)close(bpf);
-		return (-1);
-	}
-	res = send_wakeup(bpf, &macaddr);
-	(void)close(bpf);
-	return (res);
 }
 
 static int
@@ -94,25 +88,49 @@ bind_if_to_bpf(char const *ifname, int bpf)
 	u_int dlt;
 
 	if (strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)) >=
-	    sizeof(ifr.ifr_name)) {
+	    sizeof(ifr.ifr_name))
-		warnx("interface name too long: %s", ifname);
 		return (-1);
-	}
+
-	if (ioctl(bpf, BIOCSETIF, &ifr) == -1) {
+	if (ioctl(bpf, BIOCSETIF, &ifr) == -1)
-		warn("ioctl(%s)", "BIOCSETIF");
 		return (-1);
-	}
+
-	if (ioctl(bpf, BIOCGDLT, &dlt) == -1) {
+	if (ioctl(bpf, BIOCGDLT, &dlt) == -1)
-		warn("ioctl(%s)", "BIOCGDLT");
 		return (-1);
-	}
+
-	if (dlt != DLT_EN10MB) {
+	if (dlt != DLT_EN10MB)
-		warnx("incompatible media");
 		return (-1);
-	}
+
 	return (0);
 }
 
+static int
+find_ether(char *dst, size_t len)
+{
+	struct ifaddrs *ifap, *ifa;
+	struct sockaddr_dl *sdl = NULL;
+	int nifs;
+
+	if (dst == NULL || len == 0)
+		return 0;
+
+	if (getifaddrs(&ifap) != 0)
+		return -1;
+
+	/* XXX also check the link state */
+	for (nifs = 0, ifa = ifap; ifa; ifa = ifa->ifa_next)
+		if (ifa->ifa_addr->sa_family == AF_LINK &&
+		    ifa->ifa_flags & IFF_UP && ifa->ifa_flags & IFF_RUNNING) {
+			sdl = (struct sockaddr_dl *)ifa->ifa_addr;
+			if (sdl->sdl_type == IFT_ETHER) {
+				strlcpy(dst, ifa->ifa_name, len);
+				nifs++;
+			}
+		}
+
+	freeifaddrs(ifap);
+	return nifs == 1 ? 0 : -1;
+}
+
 static int
 get_ether(char const *text, struct ether_addr *addr)
 {
@@ -165,14 +183,31 @@ send_wakeup(int bpf, struct ether_addr const *addr)
 int
 main(int argc, char *argv[])
 {
-	int n;
+	int bpf, n;
+	char ifname[IF_NAMESIZE];
 
-	if (argc < 3)
+	if (argc < 2)
 		usage();
 
-	for (n = 2; n < argc; n++)
+	if ((bpf = open(_PATH_BPF, O_RDWR)) == -1)
-		if (wake(argv[1], argv[n]))
+		err(1, "Cannot open bpf interface");
-			warnx("error sending Wake on LAN frame over %s to %s",
+
-			    argv[1], argv[n]);
+	n = 2;
+	if (bind_if_to_bpf(argv[1], bpf) == -1) {
+		if (find_ether(ifname, sizeof(ifname)))
+			err(1, "Failed to determine ethernet interface");
+		if (bind_if_to_bpf(ifname, bpf) == -1)
+			err(1, "Cannot bind to interface `%s'", ifname);
+		--n;
+	} else
+		strlcpy(ifname, argv[1], sizeof(ifname));
+
+	if (n >= argc)
+		usage();
+	for (; n < argc; n++)
+		if (wake(bpf, argv[n]))
+			warn("Cannot send Wake on LAN frame over `%s' to `%s'",
+			    ifname, argv[n]);
+
 	return (0);
 }