Phonet: error on broadcast sending (unimplemented)

If we ever implement this, then we can stop returning an error.
Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/phonet.h

@@ -38,6 +38,7 @@
 #define PNPIPE_IFINDEX		2
 
 #define PNADDR_ANY		0
+#define PNADDR_BROADCAST	0xFC
 #define PNPORT_RESOURCE_ROUTING	0
 
 /* Values for PNPIPE_ENCAP option */

net/phonet/af_phonet.c

@@ -168,6 +168,12 @@ static int pn_send(struct sk_buff *skb, struct net_device *dev,
 		goto drop;
 	}
 
+	/* Broadcast sending is not implemented */
+	if (pn_addr(dst) == PNADDR_BROADCAST) {
+		err = -EOPNOTSUPP;
+		goto drop;
+	}
+
 	skb_reset_transport_header(skb);
 	WARN_ON(skb_headroom(skb) & 1); /* HW assumes word alignment */
 	skb_push(skb, sizeof(struct phonethdr));