[lotest] Add option to use broadcast packets for loopback testing

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/hci/commands/lotest_cmd.c

 struct lotest_options {
 	/** MTU */
 	unsigned int mtu;
+	/** Broadcast */
+	int broadcast;
 };
 
 /** "lotest" option list */
 static struct option_descriptor lotest_opts[] = {
 	OPTION_DESC ( "mtu", 'm', required_argument,
 		      struct lotest_options, mtu, parse_integer ),
+	OPTION_DESC ( "broadcast", 'b', no_argument,
+		      struct lotest_options, broadcast, parse_flag ),
 };
 
 /** "lotest" command descriptor */
 		opts.mtu = ETH_MAX_MTU;
 
 	/* Perform loopback test */
-	if ( ( rc = loopback_test ( sender, receiver, opts.mtu ) ) != 0 ) {
+	if ( ( rc = loopback_test ( sender, receiver, opts.mtu,
+				    opts.broadcast ) ) != 0 ) {
 		printf ( "Test failed: %s\n", strerror ( rc ) );
 		return rc;
 	}

src/include/usr/lotest.h

 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 
 extern int loopback_test ( struct net_device *sender,
-			   struct net_device *receiver, size_t mtu );
+			   struct net_device *receiver,
+			   size_t mtu, int broadcast );
 
 #endif /* _USR_LOTEST_H */

src/usr/lotest.c

  * @v sender		Sending network device
  * @v receiver		Received network device
  * @v mtu		Packet size (excluding link-layer headers)
+ * @v broadcast		Use broadcast link-layer address
  * @ret rc		Return status code
  */
 int loopback_test ( struct net_device *sender, struct net_device *receiver,
-		    size_t mtu ) {
+		    size_t mtu, int broadcast ) {
 	uint8_t *buf;
 	uint32_t *seq;
 	struct io_buffer *iobuf;
+	const void *ll_dest;
 	unsigned int i;
 	unsigned int successes;
 	int rc;
 		return -ENOMEM;
 	seq = ( ( void * ) buf );
 
+	/* Determine destination address */
+	ll_dest = ( broadcast ? sender->ll_broadcast : receiver->ll_addr );
+
 	/* Print initial statistics */
-	printf ( "Performing loopback test from %s to %s with %zd byte MTU\n",
-		 sender->name, receiver->name, mtu );
+	printf ( "Performing %sloopback test from %s to %s with %zd byte MTU\n",
+		 ( broadcast ? "broadcast " : "" ), sender->name,
+		 receiver->name, mtu );
 	ifstat ( sender );
 	ifstat ( receiver );
 
 
 		/* Transmit packet */
 		if ( ( rc = net_tx ( iob_disown ( iobuf ), sender,
-				     &lotest_protocol, receiver->ll_addr,
+				     &lotest_protocol, ll_dest,
 				     sender->ll_addr ) ) != 0 ) {
 			printf ( "\nFailed to transmit packet: %s",
 				 strerror ( rc ) );