compat_ip{,v6}_setsockopt(): enumerate MCAST_... options explicitly

We want to check if optname is among the MCAST_... ones; do that as
an explicit switch.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

net/ipv4/ip_sockglue.c

@@ -1272,9 +1272,17 @@ int compat_ip_setsockopt(struct sock *sk, int level, int optname,
 	if (level != SOL_IP)
 		return -ENOPROTOOPT;
 
-	if (optname >= MCAST_JOIN_GROUP && optname <= MCAST_MSFILTER)
+	switch (optname) {
+	case MCAST_JOIN_GROUP:
+	case MCAST_LEAVE_GROUP:
+	case MCAST_JOIN_SOURCE_GROUP:
+	case MCAST_LEAVE_SOURCE_GROUP:
+	case MCAST_BLOCK_SOURCE:
+	case MCAST_UNBLOCK_SOURCE:
+	case MCAST_MSFILTER:
 		return compat_mc_setsockopt(sk, level, optname, optval, optlen,
 			ip_setsockopt);
+	}
 
 	err = do_ip_setsockopt(sk, level, optname, optval, optlen);
 #ifdef CONFIG_NETFILTER

net/ipv6/ipv6_sockglue.c

@@ -973,9 +973,17 @@ int compat_ipv6_setsockopt(struct sock *sk, int level, int optname,
 	if (level != SOL_IPV6)
 		return -ENOPROTOOPT;
 
-	if (optname >= MCAST_JOIN_GROUP && optname <= MCAST_MSFILTER)
+	switch (optname) {
+	case MCAST_JOIN_GROUP:
+	case MCAST_LEAVE_GROUP:
+	case MCAST_JOIN_SOURCE_GROUP:
+	case MCAST_LEAVE_SOURCE_GROUP:
+	case MCAST_BLOCK_SOURCE:
+	case MCAST_UNBLOCK_SOURCE:
+	case MCAST_MSFILTER:
 		return compat_mc_setsockopt(sk, level, optname, optval, optlen,
 			ipv6_setsockopt);
+	}
 
 	err = do_ipv6_setsockopt(sk, level, optname, optval, optlen);
 #ifdef CONFIG_NETFILTER