Phonet: error on broadcast sending (unimplemented)

If we ever implement this, then we can stop returning an error.

Signed-off-by: Rémi Denis-Courmont <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/linux/phonet.h

···
 #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

···
 		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));