IPVS: Add function to determine if IPv6 address is local

Add __ip_vs_addr_is_local_v6() to find out if an IPv6 address belongs to a
local interface. Use this function to decide whether to set the
IP_VS_CONN_F_LOCALNODE flag for IPv6 destinations.
Signed-off-by: Vince Busam <vbusam@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>

net/ipv4/ipvs/ip_vs_ctl.c

@@ -35,6 +35,10 @@
 
 #include <net/net_namespace.h>
 #include <net/ip.h>
+#ifdef CONFIG_IP_VS_IPV6
+#include <net/ipv6.h>
+#include <net/ip6_route.h>
+#endif
 #include <net/route.h>
 #include <net/sock.h>
 #include <net/genetlink.h>
@@ -91,6 +95,26 @@ int ip_vs_get_debug_level(void)
 }
 #endif
 
+#ifdef CONFIG_IP_VS_IPV6
+/* Taken from rt6_fill_node() in net/ipv6/route.c, is there a better way? */
+static int __ip_vs_addr_is_local_v6(const struct in6_addr *addr)
+{
+	struct rt6_info *rt;
+	struct flowi fl = {
+		.oif = 0,
+		.nl_u = {
+			.ip6_u = {
+				.daddr = *addr,
+				.saddr = { .s6_addr32 = {0, 0, 0, 0} }, } },
+	};
+
+	rt = (struct rt6_info *)ip6_route_output(&init_net, NULL, &fl);
+	if (rt && rt->rt6i_dev && (rt->rt6i_dev->flags & IFF_LOOPBACK))
+			return 1;
+
+	return 0;
+}
+#endif
 /*
  *	update_defense_level is called from keventd and from sysctl,
  *	so it needs to protect itself from softirqs
@@ -751,6 +775,14 @@ __ip_vs_update_dest(struct ip_vs_service *svc,
 	conn_flags = udest->conn_flags | IP_VS_CONN_F_INACTIVE;
 
 	/* check if local node and update the flags */
+#ifdef CONFIG_IP_VS_IPV6
+	if (svc->af == AF_INET6) {
+		if (__ip_vs_addr_is_local_v6(&udest->addr.in6)) {
+			conn_flags = (conn_flags & ~IP_VS_CONN_F_FWD_MASK)
+				| IP_VS_CONN_F_LOCALNODE;
+		}
+	} else
+#endif
 		if (inet_addr_type(&init_net, udest->addr.ip) == RTN_LOCAL) {
 			conn_flags = (conn_flags & ~IP_VS_CONN_F_FWD_MASK)
 				| IP_VS_CONN_F_LOCALNODE;
@@ -803,9 +835,19 @@ ip_vs_new_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest,
 
 	EnterFunction(2);
 
+#ifdef CONFIG_IP_VS_IPV6
+	if (svc->af == AF_INET6) {
+		atype = ipv6_addr_type(&udest->addr.in6);
+		if (!(atype & IPV6_ADDR_UNICAST) &&
+			!__ip_vs_addr_is_local_v6(&udest->addr.in6))
+			return -EINVAL;
+	} else
+#endif
+	{
 		atype = inet_addr_type(&init_net, udest->addr.ip);
 		if (atype != RTN_LOCAL && atype != RTN_UNICAST)
 			return -EINVAL;
+	}
 
 	dest = kzalloc(sizeof(struct ip_vs_dest), GFP_ATOMIC);
 	if (dest == NULL) {