[PATCH 18/34] ipvs: prevent mixing heterogeneous pools and synchronization

[Pablo Neira Ayuso <pablo@netfilter.org>]

From: Alex Gartrell <agartrell@fb.com>

The synchronization protocol is not compatible with heterogeneous pools, so
we need to verify that we're not turning both on at the same time.

Signed-off-by: Alex Gartrell <agartrell@fb.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
---
 include/net/ip_vs.h            |    4 ++++
 net/netfilter/ipvs/ip_vs_ctl.c |   15 +++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h
index 7600dbe..576d7f0 100644
--- a/include/net/ip_vs.h
+++ b/include/net/ip_vs.h
@@ -990,6 +990,10 @@ struct netns_ipvs {
 	char			backup_mcast_ifn[IP_VS_IFNAME_MAXLEN];
 	/* net name space ptr */
 	struct net		*net;            /* Needed by timer routines */
+	/* Number of heterogeneous destinations, needed because
+	 * heterogeneous are not supported when synchronization is
+	 * enabled */
+	unsigned int		mixed_address_family_dests;
 };
 
 #define DEFAULT_SYNC_THRESHOLD	3
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 6bd2cc6..462760e 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -779,6 +779,12 @@ __ip_vs_update_dest(struct ip_vs_service *svc, struct ip_vs_dest *dest,
 	struct ip_vs_scheduler *sched;
 	int conn_flags;
 
+	/* We cannot modify an address and change the address family */
+	BUG_ON(!add && udest->af != dest->af);
+
+	if (add && udest->af != svc->af)
+		ipvs->mixed_address_family_dests++;
+
 	/* set the weight and the flags */
 	atomic_set(&dest->weight, udest->weight);
 	conn_flags = udest->conn_flags & IP_VS_CONN_F_DEST_MASK;
@@ -1061,6 +1067,9 @@ static void __ip_vs_unlink_dest(struct ip_vs_service *svc,
 	list_del_rcu(&dest->n_list);
 	svc->num_dests--;
 
+	if (dest->af != svc->af)
+		net_ipvs(svc->net)->mixed_address_family_dests--;
+
 	if (svcupd) {
 		struct ip_vs_scheduler *sched;
 
@@ -3256,6 +3265,12 @@ static int ip_vs_genl_new_daemon(struct net *net, struct nlattr **attrs)
 	      attrs[IPVS_DAEMON_ATTR_SYNC_ID]))
 		return -EINVAL;
 
+	/* The synchronization protocol is incompatible with mixed family
+	 * services
+	 */
+	if (net_ipvs(net)->mixed_address_family_dests > 0)
+		return -EINVAL;
+
 	return start_sync_thread(net,
 				 nla_get_u32(attrs[IPVS_DAEMON_ATTR_STATE]),
 				 nla_data(attrs[IPVS_DAEMON_ATTR_MCAST_IFN]),
-- 
1.7.10.4