2 files changed, 36 insertions, 1 deletions

diff --git a/sbin/ifconfig/ifconfig.8 b/sbin/ifconfig/ifconfig.8
index cd0c6c637b91..e56401008b5f 100644
--- a/sbin/ifconfig/ifconfig.8
+++ b/sbin/ifconfig/ifconfig.8
@@ -189,6 +189,16 @@ This action does not automatically disable routes using the interface.
 .\" IP encapsulation of
 .\" .Tn CLNP
 .\" packets is done differently.
+.It Cm lladdr Ar addr
+Set the link-level address on an interface. This can be used to
+e.g. set a new MAC address on an ethernet interface, though the
+mechanism used is not ethernet-specific. The address
+.Ar addr
+is specified as a series of colon-separated hex digits.
+If the interface is already
+up when this option is used, it will be briefly brought down and
+then brought back up again in order to insure that the receive
+filter in the underlying ethernet hardware is properly reprogrammed.
 .It Cm media Ar type
 If the driver supports the media selection system, set the media type
 of the interface to
diff --git a/sbin/ifconfig/ifconfig.c b/sbin/ifconfig/ifconfig.c
index a3c75ca8f89b..52d403d1a680 100644
--- a/sbin/ifconfig/ifconfig.c
+++ b/sbin/ifconfig/ifconfig.c
@@ -53,6 +53,7 @@ static const char rcsid[] =
 #include <sys/module.h>
 #include <sys/linker.h>
 
+#include <net/ethernet.h>
 #include <net/if.h>
 #include <net/if_var.h>
 #include <net/if_dl.h>
@@ -153,7 +154,7 @@ c_func	setifprefixlen;
 c_func	setip6flags;
 #endif
 c_func	setifipdst;
-c_func	setifflags, setifmetric, setifmtu;
+c_func	setifflags, setifmetric, setifmtu, setiflladdr;
 
 
 #define	NEXTARG		0xffffff
@@ -212,6 +213,7 @@ struct	cmd {
 	{ "compress",	IFF_LINK0,	setifflags },
 	{ "noicmp",	IFF_LINK1,	setifflags },
 	{ "mtu",	NEXTARG,	setifmtu },
+	{ "lladdr",	NEXTARG,	setiflladdr },
 	{ 0,		0,		setifaddr },
 	{ 0,		0,		setifdstaddr },
 };
@@ -815,6 +817,29 @@ setifmtu(val, dummy, s, afp)
 		warn("ioctl (set mtu)");
 }
 
+void
+setiflladdr(val, dummy, s, afp)
+	const char *val;
+	int dummy __unused;
+	int s;
+	const struct afswtch *afp;
+{
+	struct ether_addr	*ea;
+
+	ea = ether_aton(val);
+	if (ea == NULL) {
+		warn("malformed link-level address");
+		return;
+	}
+	strncpy(ifr.ifr_name, name, sizeof (ifr.ifr_name));
+	ifr.ifr_addr.sa_len = ETHER_ADDR_LEN;
+	ifr.ifr_addr.sa_family = AF_LINK;
+	bcopy(ea, ifr.ifr_addr.sa_data, ETHER_ADDR_LEN);
+	if (ioctl(s, SIOCSIFLLADDR, (caddr_t)&ifr) < 0)
+		warn("ioctl (set lladdr)");
+
+	return;
+}
 
 #define	IFFBITS \
 "\020\1UP\2BROADCAST\3DEBUG\4LOOPBACK\5POINTOPOINT\6SMART\7RUNNING" \