Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index 7207427..09b1dd8 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -1,14 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	Handle incoming frames
  *	Linux ethernet bridge
  *
  *	Authors:
  *	Lennert Buytenhek		<buytenh@gnu.org>
- *
- *	This program is free software; you can redistribute it and/or
- *	modify it under the terms of the GNU General Public License
- *	as published by the Free Software Foundation; either version
- *	2 of the License, or (at your option) any later version.
  */
 
 #include <linux/slab.h>
@@ -16,6 +12,9 @@
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/netfilter_bridge.h>
+#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
+#include <net/netfilter/nf_queue.h>
+#endif
 #include <linux/neighbour.h>
 #include <net/arp.h>
 #include <linux/export.h>
@@ -23,10 +22,6 @@
 #include "br_private.h"
 #include "br_private_tunnel.h"
 
-/* Hook for brouter */
-br_should_route_hook_t __rcu *br_should_route_hook __read_mostly;
-EXPORT_SYMBOL(br_should_route_hook);
-
 static int
 br_netif_receive_skb(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
@@ -79,7 +74,6 @@
 	struct net_bridge_fdb_entry *dst = NULL;
 	struct net_bridge_mdb_entry *mdst;
 	bool local_rcv, mcast_hit = false;
-	const unsigned char *dest;
 	struct net_bridge *br;
 	u16 vid = 0;
 
@@ -97,10 +91,9 @@
 		br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, false);
 
 	local_rcv = !!(br->dev->flags & IFF_PROMISC);
-	dest = eth_hdr(skb)->h_dest;
-	if (is_multicast_ether_addr(dest)) {
+	if (is_multicast_ether_addr(eth_hdr(skb)->h_dest)) {
 		/* by definition the broadcast is also a multicast address */
-		if (is_broadcast_ether_addr(dest)) {
+		if (is_broadcast_ether_addr(eth_hdr(skb)->h_dest)) {
 			pkt_type = BR_PKT_BROADCAST;
 			local_rcv = true;
 		} else {
@@ -122,7 +115,7 @@
 		br_do_proxy_suppress_arp(skb, br, vid, p);
 	} else if (IS_ENABLED(CONFIG_IPV6) &&
 		   skb->protocol == htons(ETH_P_IPV6) &&
-		   br->neigh_suppress_enabled &&
+		   br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED) &&
 		   pskb_may_pull(skb, sizeof(struct ipv6hdr) +
 				 sizeof(struct nd_msg)) &&
 		   ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) {
@@ -150,7 +143,7 @@
 		}
 		break;
 	case BR_PKT_UNICAST:
-		dst = br_fdb_find_rcu(br, dest, vid);
+		dst = br_fdb_find_rcu(br, eth_hdr(skb)->h_dest, vid);
 	default:
 		break;
 	}
@@ -188,20 +181,72 @@
 	u16 vid = 0;
 
 	/* check if vlan is allowed, to avoid spoofing */
-	if (p->flags & BR_LEARNING && br_should_learn(p, skb, &vid))
+	if ((p->flags & BR_LEARNING) &&
+	    !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, false);
 }
 
 /* note: already called with rcu_read_lock */
 static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
-	struct net_bridge_port *p = br_port_get_rcu(skb->dev);
-
 	__br_handle_local_finish(skb);
 
-	BR_INPUT_SKB_CB(skb)->brdev = p->br->dev;
-	br_pass_frame_up(skb);
-	return 0;
+	/* return 1 to signal the okfn() was called so it's ok to use the skb */
+	return 1;
+}
+
+static int nf_hook_bridge_pre(struct sk_buff *skb, struct sk_buff **pskb)
+{
+#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
+	struct nf_hook_entries *e = NULL;
+	struct nf_hook_state state;
+	unsigned int verdict, i;
+	struct net *net;
+	int ret;
+
+	net = dev_net(skb->dev);
+#ifdef HAVE_JUMP_LABEL
+	if (!static_key_false(&nf_hooks_needed[NFPROTO_BRIDGE][NF_BR_PRE_ROUTING]))
+		goto frame_finish;
+#endif
+
+	e = rcu_dereference(net->nf.hooks_bridge[NF_BR_PRE_ROUTING]);
+	if (!e)
+		goto frame_finish;
+
+	nf_hook_state_init(&state, NF_BR_PRE_ROUTING,
+			   NFPROTO_BRIDGE, skb->dev, NULL, NULL,
+			   net, br_handle_frame_finish);
+
+	for (i = 0; i < e->num_hook_entries; i++) {
+		verdict = nf_hook_entry_hookfn(&e->hooks[i], skb, &state);
+		switch (verdict & NF_VERDICT_MASK) {
+		case NF_ACCEPT:
+			if (BR_INPUT_SKB_CB(skb)->br_netfilter_broute) {
+				*pskb = skb;
+				return RX_HANDLER_PASS;
+			}
+			break;
+		case NF_DROP:
+			kfree_skb(skb);
+			return RX_HANDLER_CONSUMED;
+		case NF_QUEUE:
+			ret = nf_queue(skb, &state, i, verdict);
+			if (ret == 1)
+				continue;
+			return RX_HANDLER_CONSUMED;
+		default: /* STOLEN */
+			return RX_HANDLER_CONSUMED;
+		}
+	}
+frame_finish:
+	net = dev_net(skb->dev);
+	br_handle_frame_finish(net, NULL, skb);
+#else
+	br_handle_frame_finish(dev_net(skb->dev), NULL, skb);
+#endif
+	return RX_HANDLER_CONSUMED;
 }
 
 /*
@@ -213,7 +258,6 @@
 	struct net_bridge_port *p;
 	struct sk_buff *skb = *pskb;
 	const unsigned char *dest = eth_hdr(skb)->h_dest;
-	br_should_route_hook_t *rhook;
 
 	if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
 		return RX_HANDLER_PASS;
@@ -225,6 +269,8 @@
 	if (!skb)
 		return RX_HANDLER_CONSUMED;
 
+	memset(skb->cb, 0, sizeof(struct br_input_skb_cb));
+
 	p = br_port_get_rcu(skb->dev);
 	if (p->flags & BR_VLAN_TUNNEL) {
 		if (br_handle_ingress_vlan_tunnel(skb, p,
@@ -278,32 +324,28 @@
 				goto forward;
 		}
 
-		/* Deliver packet to local host only */
-		NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, dev_net(skb->dev),
-			NULL, skb, skb->dev, NULL, br_handle_local_finish);
-		return RX_HANDLER_CONSUMED;
+		/* The else clause should be hit when nf_hook():
+		 *   - returns < 0 (drop/error)
+		 *   - returns = 0 (stolen/nf_queue)
+		 * Thus return 1 from the okfn() to signal the skb is ok to pass
+		 */
+		if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
+			    dev_net(skb->dev), NULL, skb, skb->dev, NULL,
+			    br_handle_local_finish) == 1) {
+			return RX_HANDLER_PASS;
+		} else {
+			return RX_HANDLER_CONSUMED;
+		}
 	}
 
 forward:
 	switch (p->state) {
 	case BR_STATE_FORWARDING:
-		rhook = rcu_dereference(br_should_route_hook);
-		if (rhook) {
-			if ((*rhook)(skb)) {
-				*pskb = skb;
-				return RX_HANDLER_PASS;
-			}
-			dest = eth_hdr(skb)->h_dest;
-		}
-		/* fall through */
 	case BR_STATE_LEARNING:
 		if (ether_addr_equal(p->br->dev->dev_addr, dest))
 			skb->pkt_type = PACKET_HOST;
 
-		NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING,
-			dev_net(skb->dev), NULL, skb, skb->dev, NULL,
-			br_handle_frame_finish);
-		break;
+		return nf_hook_bridge_pre(skb, pskb);
 	default:
 drop:
 		kfree_skb(skb);