1 files changed, 441 insertions, 0 deletions

diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
new file mode 100644
index 000000000..6bb272894
--- /dev/null
+++ b/net/bridge/br_input.c
@@ -0,0 +1,441 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	Handle incoming frames
+ *	Linux ethernet bridge
+ *
+ *	Authors:
+ *	Lennert Buytenhek		<buytenh@gnu.org>
+ */
+
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#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 <net/dsa.h>
+#include <linux/export.h>
+#include <linux/rculist.h>
+#include "br_private.h"
+#include "br_private_tunnel.h"
+
+static int
+br_netif_receive_skb(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	br_drop_fake_rtable(skb);
+	return netif_receive_skb(skb);
+}
+
+static int br_pass_frame_up(struct sk_buff *skb)
+{
+	struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev;
+	struct net_bridge *br = netdev_priv(brdev);
+	struct net_bridge_vlan_group *vg;
+
+	dev_sw_netstats_rx_add(brdev, skb->len);
+
+	vg = br_vlan_group_rcu(br);
+
+	/* Reset the offload_fwd_mark because there could be a stacked
+	 * bridge above, and it should not think this bridge it doing
+	 * that bridge's work forwarding out its ports.
+	 */
+	br_switchdev_frame_unmark(skb);
+
+	/* Bridge is just like any other port.  Make sure the
+	 * packet is allowed except in promisc mode when someone
+	 * may be running packet capture.
+	 */
+	if (!(brdev->flags & IFF_PROMISC) &&
+	    !br_allowed_egress(vg, skb)) {
+		kfree_skb(skb);
+		return NET_RX_DROP;
+	}
+
+	indev = skb->dev;
+	skb->dev = brdev;
+	skb = br_handle_vlan(br, NULL, vg, skb);
+	if (!skb)
+		return NET_RX_DROP;
+	/* update the multicast stats if the packet is IGMP/MLD */
+	br_multicast_count(br, NULL, skb, br_multicast_igmp_type(skb),
+			   BR_MCAST_DIR_TX);
+
+	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
+		       dev_net(indev), NULL, skb, indev, NULL,
+		       br_netif_receive_skb);
+}
+
+/* note: already called with rcu_read_lock */
+int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	struct net_bridge_port *p = br_port_get_rcu(skb->dev);
+	enum br_pkt_type pkt_type = BR_PKT_UNICAST;
+	struct net_bridge_fdb_entry *dst = NULL;
+	struct net_bridge_mcast_port *pmctx;
+	struct net_bridge_mdb_entry *mdst;
+	bool local_rcv, mcast_hit = false;
+	struct net_bridge_mcast *brmctx;
+	struct net_bridge_vlan *vlan;
+	struct net_bridge *br;
+	u16 vid = 0;
+	u8 state;
+
+	if (!p)
+		goto drop;
+
+	br = p->br;
+
+	if (br_mst_is_enabled(br)) {
+		state = BR_STATE_FORWARDING;
+	} else {
+		if (p->state == BR_STATE_DISABLED)
+			goto drop;
+
+		state = p->state;
+	}
+
+	brmctx = &p->br->multicast_ctx;
+	pmctx = &p->multicast_ctx;
+	if (!br_allowed_ingress(p->br, nbp_vlan_group_rcu(p), skb, &vid,
+				&state, &vlan))
+		goto out;
+
+	if (p->flags & BR_PORT_LOCKED) {
+		struct net_bridge_fdb_entry *fdb_src =
+			br_fdb_find_rcu(br, eth_hdr(skb)->h_source, vid);
+
+		if (!fdb_src || READ_ONCE(fdb_src->dst) != p ||
+		    test_bit(BR_FDB_LOCAL, &fdb_src->flags))
+			goto drop;
+	}
+
+	nbp_switchdev_frame_mark(p, skb);
+
+	/* insert into forwarding database after filtering to avoid spoofing */
+	if (p->flags & BR_LEARNING)
+		br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, 0);
+
+	local_rcv = !!(br->dev->flags & IFF_PROMISC);
+	if (is_multicast_ether_addr(eth_hdr(skb)->h_dest)) {
+		/* by definition the broadcast is also a multicast address */
+		if (is_broadcast_ether_addr(eth_hdr(skb)->h_dest)) {
+			pkt_type = BR_PKT_BROADCAST;
+			local_rcv = true;
+		} else {
+			pkt_type = BR_PKT_MULTICAST;
+			if (br_multicast_rcv(&brmctx, &pmctx, vlan, skb, vid))
+				goto drop;
+		}
+	}
+
+	if (state == BR_STATE_LEARNING)
+		goto drop;
+
+	BR_INPUT_SKB_CB(skb)->brdev = br->dev;
+	BR_INPUT_SKB_CB(skb)->src_port_isolated = !!(p->flags & BR_ISOLATED);
+
+	if (IS_ENABLED(CONFIG_INET) &&
+	    (skb->protocol == htons(ETH_P_ARP) ||
+	     skb->protocol == htons(ETH_P_RARP))) {
+		br_do_proxy_suppress_arp(skb, br, vid, p);
+	} else if (IS_ENABLED(CONFIG_IPV6) &&
+		   skb->protocol == htons(ETH_P_IPV6) &&
+		   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) {
+			struct nd_msg *msg, _msg;
+
+			msg = br_is_nd_neigh_msg(skb, &_msg);
+			if (msg)
+				br_do_suppress_nd(skb, br, vid, p, msg);
+	}
+
+	switch (pkt_type) {
+	case BR_PKT_MULTICAST:
+		mdst = br_mdb_get(brmctx, skb, vid);
+		if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
+		    br_multicast_querier_exists(brmctx, eth_hdr(skb), mdst)) {
+			if ((mdst && mdst->host_joined) ||
+			    br_multicast_is_router(brmctx, skb)) {
+				local_rcv = true;
+				DEV_STATS_INC(br->dev, multicast);
+			}
+			mcast_hit = true;
+		} else {
+			local_rcv = true;
+			DEV_STATS_INC(br->dev, multicast);
+		}
+		break;
+	case BR_PKT_UNICAST:
+		dst = br_fdb_find_rcu(br, eth_hdr(skb)->h_dest, vid);
+		break;
+	default:
+		break;
+	}
+
+	if (dst) {
+		unsigned long now = jiffies;
+
+		if (test_bit(BR_FDB_LOCAL, &dst->flags))
+			return br_pass_frame_up(skb);
+
+		if (now != dst->used)
+			dst->used = now;
+		br_forward(dst->dst, skb, local_rcv, false);
+	} else {
+		if (!mcast_hit)
+			br_flood(br, skb, pkt_type, local_rcv, false);
+		else
+			br_multicast_flood(mdst, skb, brmctx, local_rcv, false);
+	}
+
+	if (local_rcv)
+		return br_pass_frame_up(skb);
+
+out:
+	return 0;
+drop:
+	kfree_skb(skb);
+	goto out;
+}
+EXPORT_SYMBOL_GPL(br_handle_frame_finish);
+
+static void __br_handle_local_finish(struct sk_buff *skb)
+{
+	struct net_bridge_port *p = br_port_get_rcu(skb->dev);
+	u16 vid = 0;
+
+	/* 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);
+}
+
+/* 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);
+
+	/* 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;
+}
+
+/* Return 0 if the frame was not processed otherwise 1
+ * note: already called with rcu_read_lock
+ */
+static int br_process_frame_type(struct net_bridge_port *p,
+				 struct sk_buff *skb)
+{
+	struct br_frame_type *tmp;
+
+	hlist_for_each_entry_rcu(tmp, &p->br->frame_type_list, list)
+		if (unlikely(tmp->type == skb->protocol))
+			return tmp->frame_handler(p, skb);
+
+	return 0;
+}
+
+/*
+ * Return NULL if skb is handled
+ * note: already called with rcu_read_lock
+ */
+static rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
+{
+	struct net_bridge_port *p;
+	struct sk_buff *skb = *pskb;
+	const unsigned char *dest = eth_hdr(skb)->h_dest;
+
+	if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
+		return RX_HANDLER_PASS;
+
+	if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
+		goto drop;
+
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	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)
+		br_handle_ingress_vlan_tunnel(skb, p, nbp_vlan_group_rcu(p));
+
+	if (unlikely(is_link_local_ether_addr(dest))) {
+		u16 fwd_mask = p->br->group_fwd_mask_required;
+
+		/*
+		 * See IEEE 802.1D Table 7-10 Reserved addresses
+		 *
+		 * Assignment		 		Value
+		 * Bridge Group Address		01-80-C2-00-00-00
+		 * (MAC Control) 802.3		01-80-C2-00-00-01
+		 * (Link Aggregation) 802.3	01-80-C2-00-00-02
+		 * 802.1X PAE address		01-80-C2-00-00-03
+		 *
+		 * 802.1AB LLDP 		01-80-C2-00-00-0E
+		 *
+		 * Others reserved for future standardization
+		 */
+		fwd_mask |= p->group_fwd_mask;
+		switch (dest[5]) {
+		case 0x00:	/* Bridge Group Address */
+			/* If STP is turned off,
+			   then must forward to keep loop detection */
+			if (p->br->stp_enabled == BR_NO_STP ||
+			    fwd_mask & (1u << dest[5]))
+				goto forward;
+			*pskb = skb;
+			__br_handle_local_finish(skb);
+			return RX_HANDLER_PASS;
+
+		case 0x01:	/* IEEE MAC (Pause) */
+			goto drop;
+
+		case 0x0E:	/* 802.1AB LLDP */
+			fwd_mask |= p->br->group_fwd_mask;
+			if (fwd_mask & (1u << dest[5]))
+				goto forward;
+			*pskb = skb;
+			__br_handle_local_finish(skb);
+			return RX_HANDLER_PASS;
+
+		default:
+			/* Allow selective forwarding for most other protocols */
+			fwd_mask |= p->br->group_fwd_mask;
+			if (fwd_mask & (1u << dest[5]))
+				goto forward;
+		}
+
+		/* 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;
+		}
+	}
+
+	if (unlikely(br_process_frame_type(p, skb)))
+		return RX_HANDLER_PASS;
+
+forward:
+	if (br_mst_is_enabled(p->br))
+		goto defer_stp_filtering;
+
+	switch (p->state) {
+	case BR_STATE_FORWARDING:
+	case BR_STATE_LEARNING:
+defer_stp_filtering:
+		if (ether_addr_equal(p->br->dev->dev_addr, dest))
+			skb->pkt_type = PACKET_HOST;
+
+		return nf_hook_bridge_pre(skb, pskb);
+	default:
+drop:
+		kfree_skb(skb);
+	}
+	return RX_HANDLER_CONSUMED;
+}
+
+/* This function has no purpose other than to appease the br_port_get_rcu/rtnl
+ * helpers which identify bridged ports according to the rx_handler installed
+ * on them (so there _needs_ to be a bridge rx_handler even if we don't need it
+ * to do anything useful). This bridge won't support traffic to/from the stack,
+ * but only hardware bridging. So return RX_HANDLER_PASS so we don't steal
+ * frames from the ETH_P_XDSA packet_type handler.
+ */
+static rx_handler_result_t br_handle_frame_dummy(struct sk_buff **pskb)
+{
+	return RX_HANDLER_PASS;
+}
+
+rx_handler_func_t *br_get_rx_handler(const struct net_device *dev)
+{
+	if (netdev_uses_dsa(dev))
+		return br_handle_frame_dummy;
+
+	return br_handle_frame;
+}
+
+void br_add_frame(struct net_bridge *br, struct br_frame_type *ft)
+{
+	hlist_add_head_rcu(&ft->list, &br->frame_type_list);
+}
+
+void br_del_frame(struct net_bridge *br, struct br_frame_type *ft)
+{
+	struct br_frame_type *tmp;
+
+	hlist_for_each_entry(tmp, &br->frame_type_list, list)
+		if (ft == tmp) {
+			hlist_del_rcu(&ft->list);
+			return;
+		}
+}