ip: add support for multicast rules

index e94981d..0d8ef9e 100644
@@ -7,6 +7,13 @@
 #include <linux/if_addr.h>
 #include <linux/neighbour.h>
 
+/* rtnetlink families. Values up to 127 are reserved for real address
+ * families, values above 128 may be used arbitrarily.
+ */
+#define RTNL_FAMILY_IPMR		128
+#define RTNL_FAMILY_IP6MR		129
+#define RTNL_FAMILY_MAX			129
+
 /****
  *		Routing/neighbour discovery messages.
  ****/

index e0cf175..9f29533 100644
@@ -42,7 +42,7 @@ static void usage(void)
 "Usage: ip [ OPTIONS ] OBJECT { COMMAND | help }\n"
 "       ip [ -force ] -batch filename\n"
 "where  OBJECT := { link | addr | addrlabel | route | rule | neigh | ntable |\n"
-"                   tunnel | tuntap | maddr | mroute | monitor | xfrm }\n"
+"                   tunnel | tuntap | maddr | mroute | mrule | monitor | xfrm }\n"
 "       OPTIONS := { -V[ersion] | -s[tatistics] | -d[etails] | -r[esolve] |\n"
 "                    -f[amily] { inet | inet6 | ipx | dnet | link } |\n"
 "                    -o[neline] | -t[imestamp] | -b[atch] [filename] |\n"

@@ -76,6 +76,7 @@ static const struct cmd {
 	{ "monitor",	do_ipmonitor },
 	{ "xfrm",	do_xfrm },
 	{ "mroute",	do_multiroute },
+	{ "mrule",	do_multirule },
 	{ "help",	do_help },
 	{ 0 }
 };

index c857667..a114186 100644
@@ -37,6 +37,7 @@ extern int do_iplink(int argc, char **argv);
 extern int do_ipmonitor(int argc, char **argv);
 extern int do_multiaddr(int argc, char **argv);
 extern int do_multiroute(int argc, char **argv);
+extern int do_multirule(int argc, char **argv);
 extern int do_xfrm(int argc, char **argv);
 
 static inline int rtm_get_table(struct rtmsg *r, struct rtattr **tb)

index 7140375..9c8c6ef 100644
@@ -436,3 +436,20 @@ int do_iprule(int argc, char **argv)
 	exit(-1);
 }
 
+int do_multirule(int argc, char **argv)
+{
+	switch (preferred_family) {
+	case AF_UNSPEC:
+	case AF_INET:
+		preferred_family = RTNL_FAMILY_IPMR;
+		break;
+	case AF_INET6:
+		preferred_family = RTNL_FAMILY_IP6MR;
+		break;
+	default:
+		fprintf(stderr, "Multicast rules are only supported for IPv4/IPv6\n");
+		exit(-1);
+	}
+
+	return do_iprule(argc, argv);
+}