From: Stephen Hemminger <stephen@networkplumber.org>
Subject: bridge: allow receiption on disabled port

When an ethernet device is enslaved to a bridge, and the bridge STP
detects loss of carrier (or operational state down), then normally
packet receiption is blocked.

This breaks control applications like WPA which maybe expecting to
receive packets to negotiate to bring link up. The bridge needs to
block forwarding packets from these disabled ports, but there is no
hard requirement to not allow local packet delivery.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -231,7 +231,10 @@ static void __br_handle_local_finish(str
 /* note: already called with rcu_read_lock */
 static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
-	__br_handle_local_finish(skb);
+	struct net_bridge_port *p = br_port_get_rcu(skb->dev);
+
+	if (p->state != BR_STATE_DISABLED)
+		__br_handle_local_finish(skb);
 
 	/* return 1 to signal the okfn() was called so it's ok to use the skb */
 	return 1;
@@ -321,6 +324,17 @@ rx_handler_result_t br_handle_frame(stru
 
 forward:
 	switch (p->state) {
+	case BR_STATE_DISABLED:
+		if (ether_addr_equal(p->br->dev->dev_addr, dest))
+			skb->pkt_type = PACKET_HOST;
+
+		if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING,
+			dev_net(skb->dev), NULL, skb, skb->dev, NULL,
+			br_handle_local_finish) == 1) {
+			return RX_HANDLER_PASS;
+		}
+		break;
+
 	case BR_STATE_FORWARDING:
 		rhook = rcu_dereference(br_should_route_hook);
 		if (rhook) {
