[net-next v2 02/11] net: bridge: mcast: add wrappers for router node retrieval

["Linus Lüssing" <linus.luessing@c0d3.blue>]

In preparation for the upcoming split of multicast router state into
their IPv4 and IPv6 variants and to avoid IPv6 #ifdef clutter later add
two wrapper functions for router node retrieval in the payload
forwarding code.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
---
 net/bridge/br_forward.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index 3b67184..b5ec4f9 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -264,6 +264,16 @@ static void maybe_deliver_addr(struct net_bridge_port *p, struct sk_buff *skb,
 	__br_forward(p, skb, local_orig);
 }
 
+static inline struct hlist_node *
+br_multicast_get_first_rport_node(struct net_bridge *b, struct sk_buff *skb) {
+	return rcu_dereference(hlist_first_rcu(&b->ip4_mc_router_list));
+}
+
+static inline struct net_bridge_port *
+br_multicast_rport_from_node(struct hlist_node *rp, struct sk_buff *skb) {
+	return hlist_entry_safe(rp, struct net_bridge_port, ip4_rlist);
+}
+
 /* called with rcu_read_lock */
 void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
 			struct sk_buff *skb,
@@ -276,7 +286,8 @@ void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
 	bool allow_mode_include = true;
 	struct hlist_node *rp;
 
-	rp = rcu_dereference(hlist_first_rcu(&br->router_list));
+	rp = br_multicast_get_first_rport_node(br, skb);
+
 	if (mdst) {
 		p = rcu_dereference(mdst->ports);
 		if (br_multicast_should_handle_mode(br, mdst->addr.proto) &&
@@ -290,7 +301,7 @@ void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
 		struct net_bridge_port *port, *lport, *rport;
 
 		lport = p ? p->key.port : NULL;
-		rport = hlist_entry_safe(rp, struct net_bridge_port, ip4_rlist);
+		rport = br_multicast_rport_from_node(rp, skb);
 
 		if ((unsigned long)lport > (unsigned long)rport) {
 			port = lport;
-- 
2.31.0