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
@@ -146,11 +146,13 @@ EXPORT_SYMBOL_GPL(br_handle_frame_finish
 static int br_handle_local_finish(struct sk_buff *skb)
 {
 	struct net_bridge_port *p = br_port_get_rcu(skb->dev);
-	u16 vid = 0;
+	if (p->state != BR_STATE_DISABLED) {
+		u16 vid = 0;
 
-	/* check if vlan is allowed, to avoid spoofing */
-	if (p->flags & BR_LEARNING && br_should_learn(p, skb, &vid))
-		br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false);
+		/* check if vlan is allowed, to avoid spoofing */
+		if (p->flags & BR_LEARNING && br_should_learn(p, skb, &vid))
+			br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false);
+	}
 	return 0;	 /* process further */
 }
 
@@ -224,6 +226,18 @@ 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, skb, skb->dev, NULL,
+			br_handle_local_finish))
+			break;
+
+		BR_INPUT_SKB_CB(skb)->brdev = p->br->dev;
+		br_pass_frame_up(skb);
+		break;
+
 	case BR_STATE_FORWARDING:
 		rhook = rcu_dereference(br_should_route_hook);
 		if (rhook) {
