net: bridge: fdb: eliminate extra port state tests from fast-path (5d1fcaf3) · Commits · 戴 / test

When commit ("[BRIDGE]: Packets leaking out of disabled/blocked ports.") introduced the port state tests in br_fdb_update() it was to avoid learning/refreshing from STP BPDUs, it was also used to avoid learning/refreshing from user-space with NTF_USE. Those two tests are done for every packet entering the bridge if it's learning, but for the fast-path we already have them checked in br_handle_frame() and is unnecessary to do it again. Thus push the checks to the unlikely cases and drop them from br_fdb_update(), the new nbp_state_should_learn() helper is used to determine if the port state allows br_fdb_update() to be called. The two places which need to do it manually are: - user-space add call with NTF_USE set - link-local packet learning done in __br_handle_local_finish() Signed-off-by:

Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/bridge/br_fdb.c

+3 −5

Original line number	Diff line number	Diff line
		@@ -566,11 +566,6 @@ void br_fdb_update(struct net_bridge br, struct net_bridge_port source,
		if (hold_time(br) == 0)
		return;

		/* ignore packets unless we are using this port */
		if (!(source->state == BR_STATE_LEARNING \|\|
		source->state == BR_STATE_FORWARDING))
		return;

		fdb = fdb_find_rcu(&br->fdb_hash_tbl, addr, vid);
		if (likely(fdb)) {
		/* attempt to update an entry for a local interface */
		@@ -886,6 +881,9 @@ static int __br_fdb_add(struct ndmsg ndm, struct net_bridge br,
		br->dev->name);
		return -EINVAL;
		}
		if (!nbp_state_should_learn(p))
		return 0;

		local_bh_disable();
		rcu_read_lock();
		br_fdb_update(br, p, addr, vid, BIT(BR_FDB_ADDED_BY_USER));

net/bridge/br_input.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -182,6 +182,7 @@ static void __br_handle_local_finish(struct sk_buff *skb)

		/* check if vlan is allowed, to avoid spoofing */
		if ((p->flags & BR_LEARNING) &&
		nbp_state_should_learn(p) &&
		!br_opt_get(p->br, BROPT_NO_LL_LEARN) &&
		br_should_learn(p, skb, &vid))
		br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, 0);

net/bridge/br_private.h

+5 −0

Original line number	Diff line number	Diff line
		@@ -500,6 +500,11 @@ static inline bool br_vlan_should_use(const struct net_bridge_vlan *v)
		return true;
		}

		static inline bool nbp_state_should_learn(const struct net_bridge_port *p)
		{
		return p->state == BR_STATE_LEARNING \|\| p->state == BR_STATE_FORWARDING;
		}

		static inline int br_opt_get(const struct net_bridge *br,
		enum net_bridge_opts opt)
		{

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