linux-kernel - [net-next v3 02/11] net: bridge: mcast: add wrappers for router node retrieval

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Date:   Thu, 13 May 2021 01:19:32 +0200
From:   Linus Lüssing <linus.luessing@...3.blue>
To:     netdev@...r.kernel.org
Cc:     Roopa Prabhu <roopa@...dia.com>,
        Nikolay Aleksandrov <nikolay@...dia.com>,
        Jakub Kicinski <kuba@...nel.org>,
        "David S . Miller" <davem@...emloft.net>,
        bridge@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Linus Lüssing <linus.luessing@...3.blue>
Subject: [net-next v3 02/11] net: bridge: mcast: add wrappers for router node retrieval

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@...3.blue>
---
 net/bridge/br_forward.c |  5 +++--
 net/bridge/br_private.h | 10 ++++++++++
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index eb9847a..4e591b1 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -276,7 +276,8 @@ 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->ip4_mc_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 +291,7 @@ 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;
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 26e91d2..5b9a6b2 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -864,6 +864,16 @@ static inline bool br_group_is_l2(const struct br_ip *group)
 #define mlock_dereference(X, br) \
 	rcu_dereference_protected(X, lockdep_is_held(&br->multicast_lock))
 
+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);
+}
+
 static inline bool br_multicast_is_router(struct net_bridge *br)
 {
 	return br->multicast_router == 2 ||
-- 
2.31.0