s390/qeth: reject multicast rxip addresses

There exist different commands to add unicast and multicast addresses on
the OSA card. rxip addresses are always set as unicast addresses and
thus just unicast addresses should be allowed.

Adding a multicast address now fails and a grace message is generated.
Signed-off-by: Kittipon Meesompop <kmeesomp@linux.vnet.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/s390/net/qeth_l3_sys.c

@@ -895,9 +895,26 @@ static ssize_t qeth_l3_dev_rxip_add4_show(struct device *dev,
 static int qeth_l3_parse_rxipe(const char *buf, enum qeth_prot_versions proto,
 		 u8 *addr)
 {
+	__be32 ipv4_addr;
+	struct in6_addr ipv6_addr;
+
 	if (qeth_l3_string_to_ipaddr(buf, proto, addr)) {
 		return -EINVAL;
 	}
+	if (proto == QETH_PROT_IPV4) {
+		memcpy(&ipv4_addr, addr, sizeof(ipv4_addr));
+		if (ipv4_is_multicast(ipv4_addr)) {
+			QETH_DBF_MESSAGE(2, "multicast rxip not supported.\n");
+			return -EINVAL;
+		}
+	} else if (proto == QETH_PROT_IPV6) {
+		memcpy(&ipv6_addr, addr, sizeof(ipv6_addr));
+		if (ipv6_addr_is_multicast(&ipv6_addr)) {
+			QETH_DBF_MESSAGE(2, "multicast rxip not supported.\n");
+			return -EINVAL;
+		}
+	}
+
 	return 0;
 }