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v5.9
  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 *	Handle incoming frames
  4 *	Linux ethernet bridge
  5 *
  6 *	Authors:
  7 *	Lennert Buytenhek		<buytenh@gnu.org>
 
 
 
 
 
  8 */
  9
 10#include <linux/slab.h>
 11#include <linux/kernel.h>
 12#include <linux/netdevice.h>
 13#include <linux/etherdevice.h>
 14#include <linux/netfilter_bridge.h>
 15#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
 16#include <net/netfilter/nf_queue.h>
 17#endif
 18#include <linux/neighbour.h>
 19#include <net/arp.h>
 20#include <net/dsa.h>
 21#include <linux/export.h>
 22#include <linux/rculist.h>
 23#include "br_private.h"
 24#include "br_private_tunnel.h"
 25
 
 
 
 
 26static int
 27br_netif_receive_skb(struct net *net, struct sock *sk, struct sk_buff *skb)
 28{
 29	br_drop_fake_rtable(skb);
 30	return netif_receive_skb(skb);
 31}
 32
 33static int br_pass_frame_up(struct sk_buff *skb)
 34{
 35	struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev;
 36	struct net_bridge *br = netdev_priv(brdev);
 37	struct net_bridge_vlan_group *vg;
 38	struct pcpu_sw_netstats *brstats = this_cpu_ptr(br->stats);
 39
 40	u64_stats_update_begin(&brstats->syncp);
 41	brstats->rx_packets++;
 42	brstats->rx_bytes += skb->len;
 43	u64_stats_update_end(&brstats->syncp);
 44
 45	vg = br_vlan_group_rcu(br);
 46	/* Bridge is just like any other port.  Make sure the
 47	 * packet is allowed except in promisc modue when someone
 48	 * may be running packet capture.
 49	 */
 50	if (!(brdev->flags & IFF_PROMISC) &&
 51	    !br_allowed_egress(vg, skb)) {
 52		kfree_skb(skb);
 53		return NET_RX_DROP;
 54	}
 55
 56	indev = skb->dev;
 57	skb->dev = brdev;
 58	skb = br_handle_vlan(br, NULL, vg, skb);
 59	if (!skb)
 60		return NET_RX_DROP;
 61	/* update the multicast stats if the packet is IGMP/MLD */
 62	br_multicast_count(br, NULL, skb, br_multicast_igmp_type(skb),
 63			   BR_MCAST_DIR_TX);
 64
 65	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
 66		       dev_net(indev), NULL, skb, indev, NULL,
 67		       br_netif_receive_skb);
 68}
 69
 70/* note: already called with rcu_read_lock */
 71int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 72{
 73	struct net_bridge_port *p = br_port_get_rcu(skb->dev);
 74	enum br_pkt_type pkt_type = BR_PKT_UNICAST;
 75	struct net_bridge_fdb_entry *dst = NULL;
 76	struct net_bridge_mdb_entry *mdst;
 77	bool local_rcv, mcast_hit = false;
 
 78	struct net_bridge *br;
 79	u16 vid = 0;
 80	u8 state;
 81
 82	if (!p || p->state == BR_STATE_DISABLED)
 83		goto drop;
 84
 85	state = p->state;
 86	if (!br_allowed_ingress(p->br, nbp_vlan_group_rcu(p), skb, &vid,
 87				&state))
 88		goto out;
 89
 90	nbp_switchdev_frame_mark(p, skb);
 91
 92	/* insert into forwarding database after filtering to avoid spoofing */
 93	br = p->br;
 94	if (p->flags & BR_LEARNING)
 95		br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, 0);
 96
 97	local_rcv = !!(br->dev->flags & IFF_PROMISC);
 98	if (is_multicast_ether_addr(eth_hdr(skb)->h_dest)) {
 
 99		/* by definition the broadcast is also a multicast address */
100		if (is_broadcast_ether_addr(eth_hdr(skb)->h_dest)) {
101			pkt_type = BR_PKT_BROADCAST;
102			local_rcv = true;
103		} else {
104			pkt_type = BR_PKT_MULTICAST;
105			if (br_multicast_rcv(br, p, skb, vid))
106				goto drop;
107		}
108	}
109
110	if (state == BR_STATE_LEARNING)
111		goto drop;
112
113	BR_INPUT_SKB_CB(skb)->brdev = br->dev;
114	BR_INPUT_SKB_CB(skb)->src_port_isolated = !!(p->flags & BR_ISOLATED);
115
116	if (IS_ENABLED(CONFIG_INET) &&
117	    (skb->protocol == htons(ETH_P_ARP) ||
118	     skb->protocol == htons(ETH_P_RARP))) {
119		br_do_proxy_suppress_arp(skb, br, vid, p);
120	} else if (IS_ENABLED(CONFIG_IPV6) &&
121		   skb->protocol == htons(ETH_P_IPV6) &&
122		   br_opt_get(br, BROPT_NEIGH_SUPPRESS_ENABLED) &&
123		   pskb_may_pull(skb, sizeof(struct ipv6hdr) +
124				 sizeof(struct nd_msg)) &&
125		   ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) {
126			struct nd_msg *msg, _msg;
127
128			msg = br_is_nd_neigh_msg(skb, &_msg);
129			if (msg)
130				br_do_suppress_nd(skb, br, vid, p, msg);
131	}
132
133	switch (pkt_type) {
134	case BR_PKT_MULTICAST:
135		mdst = br_mdb_get(br, skb, vid);
136		if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
137		    br_multicast_querier_exists(br, eth_hdr(skb))) {
138			if ((mdst && mdst->host_joined) ||
139			    br_multicast_is_router(br)) {
140				local_rcv = true;
141				br->dev->stats.multicast++;
142			}
143			mcast_hit = true;
144		} else {
145			local_rcv = true;
146			br->dev->stats.multicast++;
147		}
148		break;
149	case BR_PKT_UNICAST:
150		dst = br_fdb_find_rcu(br, eth_hdr(skb)->h_dest, vid);
151	default:
152		break;
153	}
154
155	if (dst) {
156		unsigned long now = jiffies;
157
158		if (test_bit(BR_FDB_LOCAL, &dst->flags))
159			return br_pass_frame_up(skb);
160
161		if (now != dst->used)
162			dst->used = now;
163		br_forward(dst->dst, skb, local_rcv, false);
164	} else {
165		if (!mcast_hit)
166			br_flood(br, skb, pkt_type, local_rcv, false);
167		else
168			br_multicast_flood(mdst, skb, local_rcv, false);
169	}
170
171	if (local_rcv)
172		return br_pass_frame_up(skb);
173
174out:
175	return 0;
176drop:
177	kfree_skb(skb);
178	goto out;
179}
180EXPORT_SYMBOL_GPL(br_handle_frame_finish);
181
182static void __br_handle_local_finish(struct sk_buff *skb)
183{
184	struct net_bridge_port *p = br_port_get_rcu(skb->dev);
185	u16 vid = 0;
186
187	/* check if vlan is allowed, to avoid spoofing */
188	if ((p->flags & BR_LEARNING) &&
189	    nbp_state_should_learn(p) &&
190	    !br_opt_get(p->br, BROPT_NO_LL_LEARN) &&
191	    br_should_learn(p, skb, &vid))
192		br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, 0);
193}
194
195/* note: already called with rcu_read_lock */
196static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
197{
198	__br_handle_local_finish(skb);
199
200	/* return 1 to signal the okfn() was called so it's ok to use the skb */
201	return 1;
202}
203
204static int nf_hook_bridge_pre(struct sk_buff *skb, struct sk_buff **pskb)
205{
206#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
207	struct nf_hook_entries *e = NULL;
208	struct nf_hook_state state;
209	unsigned int verdict, i;
210	struct net *net;
211	int ret;
212
213	net = dev_net(skb->dev);
214#ifdef HAVE_JUMP_LABEL
215	if (!static_key_false(&nf_hooks_needed[NFPROTO_BRIDGE][NF_BR_PRE_ROUTING]))
216		goto frame_finish;
217#endif
218
219	e = rcu_dereference(net->nf.hooks_bridge[NF_BR_PRE_ROUTING]);
220	if (!e)
221		goto frame_finish;
222
223	nf_hook_state_init(&state, NF_BR_PRE_ROUTING,
224			   NFPROTO_BRIDGE, skb->dev, NULL, NULL,
225			   net, br_handle_frame_finish);
226
227	for (i = 0; i < e->num_hook_entries; i++) {
228		verdict = nf_hook_entry_hookfn(&e->hooks[i], skb, &state);
229		switch (verdict & NF_VERDICT_MASK) {
230		case NF_ACCEPT:
231			if (BR_INPUT_SKB_CB(skb)->br_netfilter_broute) {
232				*pskb = skb;
233				return RX_HANDLER_PASS;
234			}
235			break;
236		case NF_DROP:
237			kfree_skb(skb);
238			return RX_HANDLER_CONSUMED;
239		case NF_QUEUE:
240			ret = nf_queue(skb, &state, i, verdict);
241			if (ret == 1)
242				continue;
243			return RX_HANDLER_CONSUMED;
244		default: /* STOLEN */
245			return RX_HANDLER_CONSUMED;
246		}
247	}
248frame_finish:
249	net = dev_net(skb->dev);
250	br_handle_frame_finish(net, NULL, skb);
251#else
252	br_handle_frame_finish(dev_net(skb->dev), NULL, skb);
253#endif
254	return RX_HANDLER_CONSUMED;
255}
256
257/*
258 * Return NULL if skb is handled
259 * note: already called with rcu_read_lock
260 */
261static rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
262{
263	struct net_bridge_port *p;
264	struct sk_buff *skb = *pskb;
265	const unsigned char *dest = eth_hdr(skb)->h_dest;
 
266
267	if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
268		return RX_HANDLER_PASS;
269
270	if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
271		goto drop;
272
273	skb = skb_share_check(skb, GFP_ATOMIC);
274	if (!skb)
275		return RX_HANDLER_CONSUMED;
276
277	memset(skb->cb, 0, sizeof(struct br_input_skb_cb));
278
279	p = br_port_get_rcu(skb->dev);
280	if (p->flags & BR_VLAN_TUNNEL) {
281		if (br_handle_ingress_vlan_tunnel(skb, p,
282						  nbp_vlan_group_rcu(p)))
283			goto drop;
284	}
285
286	if (unlikely(is_link_local_ether_addr(dest))) {
287		u16 fwd_mask = p->br->group_fwd_mask_required;
288
289		/*
290		 * See IEEE 802.1D Table 7-10 Reserved addresses
291		 *
292		 * Assignment		 		Value
293		 * Bridge Group Address		01-80-C2-00-00-00
294		 * (MAC Control) 802.3		01-80-C2-00-00-01
295		 * (Link Aggregation) 802.3	01-80-C2-00-00-02
296		 * 802.1X PAE address		01-80-C2-00-00-03
297		 *
298		 * 802.1AB LLDP 		01-80-C2-00-00-0E
299		 *
300		 * Others reserved for future standardization
301		 */
302		fwd_mask |= p->group_fwd_mask;
303		switch (dest[5]) {
304		case 0x00:	/* Bridge Group Address */
305			/* If STP is turned off,
306			   then must forward to keep loop detection */
307			if (p->br->stp_enabled == BR_NO_STP ||
308			    fwd_mask & (1u << dest[5]))
309				goto forward;
310			*pskb = skb;
311			__br_handle_local_finish(skb);
312			return RX_HANDLER_PASS;
313
314		case 0x01:	/* IEEE MAC (Pause) */
315			goto drop;
316
317		case 0x0E:	/* 802.1AB LLDP */
318			fwd_mask |= p->br->group_fwd_mask;
319			if (fwd_mask & (1u << dest[5]))
320				goto forward;
321			*pskb = skb;
322			__br_handle_local_finish(skb);
323			return RX_HANDLER_PASS;
324
325		default:
326			/* Allow selective forwarding for most other protocols */
327			fwd_mask |= p->br->group_fwd_mask;
328			if (fwd_mask & (1u << dest[5]))
329				goto forward;
330		}
331
332		/* The else clause should be hit when nf_hook():
333		 *   - returns < 0 (drop/error)
334		 *   - returns = 0 (stolen/nf_queue)
335		 * Thus return 1 from the okfn() to signal the skb is ok to pass
336		 */
337		if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
338			    dev_net(skb->dev), NULL, skb, skb->dev, NULL,
339			    br_handle_local_finish) == 1) {
340			return RX_HANDLER_PASS;
341		} else {
342			return RX_HANDLER_CONSUMED;
343		}
344	}
345
346	if (unlikely(br_mrp_process(p, skb)))
347		return RX_HANDLER_PASS;
348
349forward:
350	switch (p->state) {
351	case BR_STATE_FORWARDING:
 
 
 
 
 
 
 
 
 
352	case BR_STATE_LEARNING:
353		if (ether_addr_equal(p->br->dev->dev_addr, dest))
354			skb->pkt_type = PACKET_HOST;
355
356		return nf_hook_bridge_pre(skb, pskb);
 
 
 
357	default:
358drop:
359		kfree_skb(skb);
360	}
361	return RX_HANDLER_CONSUMED;
362}
363
364/* This function has no purpose other than to appease the br_port_get_rcu/rtnl
365 * helpers which identify bridged ports according to the rx_handler installed
366 * on them (so there _needs_ to be a bridge rx_handler even if we don't need it
367 * to do anything useful). This bridge won't support traffic to/from the stack,
368 * but only hardware bridging. So return RX_HANDLER_PASS so we don't steal
369 * frames from the ETH_P_XDSA packet_type handler.
370 */
371static rx_handler_result_t br_handle_frame_dummy(struct sk_buff **pskb)
372{
373	return RX_HANDLER_PASS;
374}
375
376rx_handler_func_t *br_get_rx_handler(const struct net_device *dev)
377{
378	if (netdev_uses_dsa(dev))
379		return br_handle_frame_dummy;
380
381	return br_handle_frame;
382}
v4.17
 
  1/*
  2 *	Handle incoming frames
  3 *	Linux ethernet bridge
  4 *
  5 *	Authors:
  6 *	Lennert Buytenhek		<buytenh@gnu.org>
  7 *
  8 *	This program is free software; you can redistribute it and/or
  9 *	modify it under the terms of the GNU General Public License
 10 *	as published by the Free Software Foundation; either version
 11 *	2 of the License, or (at your option) any later version.
 12 */
 13
 14#include <linux/slab.h>
 15#include <linux/kernel.h>
 16#include <linux/netdevice.h>
 17#include <linux/etherdevice.h>
 18#include <linux/netfilter_bridge.h>
 
 
 
 19#include <linux/neighbour.h>
 20#include <net/arp.h>
 
 21#include <linux/export.h>
 22#include <linux/rculist.h>
 23#include "br_private.h"
 24#include "br_private_tunnel.h"
 25
 26/* Hook for brouter */
 27br_should_route_hook_t __rcu *br_should_route_hook __read_mostly;
 28EXPORT_SYMBOL(br_should_route_hook);
 29
 30static int
 31br_netif_receive_skb(struct net *net, struct sock *sk, struct sk_buff *skb)
 32{
 33	br_drop_fake_rtable(skb);
 34	return netif_receive_skb(skb);
 35}
 36
 37static int br_pass_frame_up(struct sk_buff *skb)
 38{
 39	struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev;
 40	struct net_bridge *br = netdev_priv(brdev);
 41	struct net_bridge_vlan_group *vg;
 42	struct pcpu_sw_netstats *brstats = this_cpu_ptr(br->stats);
 43
 44	u64_stats_update_begin(&brstats->syncp);
 45	brstats->rx_packets++;
 46	brstats->rx_bytes += skb->len;
 47	u64_stats_update_end(&brstats->syncp);
 48
 49	vg = br_vlan_group_rcu(br);
 50	/* Bridge is just like any other port.  Make sure the
 51	 * packet is allowed except in promisc modue when someone
 52	 * may be running packet capture.
 53	 */
 54	if (!(brdev->flags & IFF_PROMISC) &&
 55	    !br_allowed_egress(vg, skb)) {
 56		kfree_skb(skb);
 57		return NET_RX_DROP;
 58	}
 59
 60	indev = skb->dev;
 61	skb->dev = brdev;
 62	skb = br_handle_vlan(br, NULL, vg, skb);
 63	if (!skb)
 64		return NET_RX_DROP;
 65	/* update the multicast stats if the packet is IGMP/MLD */
 66	br_multicast_count(br, NULL, skb, br_multicast_igmp_type(skb),
 67			   BR_MCAST_DIR_TX);
 68
 69	return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
 70		       dev_net(indev), NULL, skb, indev, NULL,
 71		       br_netif_receive_skb);
 72}
 73
 74/* note: already called with rcu_read_lock */
 75int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 76{
 77	struct net_bridge_port *p = br_port_get_rcu(skb->dev);
 78	enum br_pkt_type pkt_type = BR_PKT_UNICAST;
 79	struct net_bridge_fdb_entry *dst = NULL;
 80	struct net_bridge_mdb_entry *mdst;
 81	bool local_rcv, mcast_hit = false;
 82	const unsigned char *dest;
 83	struct net_bridge *br;
 84	u16 vid = 0;
 
 85
 86	if (!p || p->state == BR_STATE_DISABLED)
 87		goto drop;
 88
 89	if (!br_allowed_ingress(p->br, nbp_vlan_group_rcu(p), skb, &vid))
 
 
 90		goto out;
 91
 92	nbp_switchdev_frame_mark(p, skb);
 93
 94	/* insert into forwarding database after filtering to avoid spoofing */
 95	br = p->br;
 96	if (p->flags & BR_LEARNING)
 97		br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, false);
 98
 99	local_rcv = !!(br->dev->flags & IFF_PROMISC);
100	dest = eth_hdr(skb)->h_dest;
101	if (is_multicast_ether_addr(dest)) {
102		/* by definition the broadcast is also a multicast address */
103		if (is_broadcast_ether_addr(dest)) {
104			pkt_type = BR_PKT_BROADCAST;
105			local_rcv = true;
106		} else {
107			pkt_type = BR_PKT_MULTICAST;
108			if (br_multicast_rcv(br, p, skb, vid))
109				goto drop;
110		}
111	}
112
113	if (p->state == BR_STATE_LEARNING)
114		goto drop;
115
116	BR_INPUT_SKB_CB(skb)->brdev = br->dev;
 
117
118	if (IS_ENABLED(CONFIG_INET) &&
119	    (skb->protocol == htons(ETH_P_ARP) ||
120	     skb->protocol == htons(ETH_P_RARP))) {
121		br_do_proxy_suppress_arp(skb, br, vid, p);
122	} else if (IS_ENABLED(CONFIG_IPV6) &&
123		   skb->protocol == htons(ETH_P_IPV6) &&
124		   br->neigh_suppress_enabled &&
125		   pskb_may_pull(skb, sizeof(struct ipv6hdr) +
126				 sizeof(struct nd_msg)) &&
127		   ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) {
128			struct nd_msg *msg, _msg;
129
130			msg = br_is_nd_neigh_msg(skb, &_msg);
131			if (msg)
132				br_do_suppress_nd(skb, br, vid, p, msg);
133	}
134
135	switch (pkt_type) {
136	case BR_PKT_MULTICAST:
137		mdst = br_mdb_get(br, skb, vid);
138		if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
139		    br_multicast_querier_exists(br, eth_hdr(skb))) {
140			if ((mdst && mdst->host_joined) ||
141			    br_multicast_is_router(br)) {
142				local_rcv = true;
143				br->dev->stats.multicast++;
144			}
145			mcast_hit = true;
146		} else {
147			local_rcv = true;
148			br->dev->stats.multicast++;
149		}
150		break;
151	case BR_PKT_UNICAST:
152		dst = br_fdb_find_rcu(br, dest, vid);
153	default:
154		break;
155	}
156
157	if (dst) {
158		unsigned long now = jiffies;
159
160		if (dst->is_local)
161			return br_pass_frame_up(skb);
162
163		if (now != dst->used)
164			dst->used = now;
165		br_forward(dst->dst, skb, local_rcv, false);
166	} else {
167		if (!mcast_hit)
168			br_flood(br, skb, pkt_type, local_rcv, false);
169		else
170			br_multicast_flood(mdst, skb, local_rcv, false);
171	}
172
173	if (local_rcv)
174		return br_pass_frame_up(skb);
175
176out:
177	return 0;
178drop:
179	kfree_skb(skb);
180	goto out;
181}
182EXPORT_SYMBOL_GPL(br_handle_frame_finish);
183
184static void __br_handle_local_finish(struct sk_buff *skb)
185{
186	struct net_bridge_port *p = br_port_get_rcu(skb->dev);
187	u16 vid = 0;
188
189	/* check if vlan is allowed, to avoid spoofing */
190	if (p->flags & BR_LEARNING && br_should_learn(p, skb, &vid))
191		br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false);
 
 
 
192}
193
194/* note: already called with rcu_read_lock */
195static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
196{
197	struct net_bridge_port *p = br_port_get_rcu(skb->dev);
198
199	__br_handle_local_finish(skb);
 
 
200
201	BR_INPUT_SKB_CB(skb)->brdev = p->br->dev;
202	br_pass_frame_up(skb);
203	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
204}
205
206/*
207 * Return NULL if skb is handled
208 * note: already called with rcu_read_lock
209 */
210rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
211{
212	struct net_bridge_port *p;
213	struct sk_buff *skb = *pskb;
214	const unsigned char *dest = eth_hdr(skb)->h_dest;
215	br_should_route_hook_t *rhook;
216
217	if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
218		return RX_HANDLER_PASS;
219
220	if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
221		goto drop;
222
223	skb = skb_share_check(skb, GFP_ATOMIC);
224	if (!skb)
225		return RX_HANDLER_CONSUMED;
226
 
 
227	p = br_port_get_rcu(skb->dev);
228	if (p->flags & BR_VLAN_TUNNEL) {
229		if (br_handle_ingress_vlan_tunnel(skb, p,
230						  nbp_vlan_group_rcu(p)))
231			goto drop;
232	}
233
234	if (unlikely(is_link_local_ether_addr(dest))) {
235		u16 fwd_mask = p->br->group_fwd_mask_required;
236
237		/*
238		 * See IEEE 802.1D Table 7-10 Reserved addresses
239		 *
240		 * Assignment		 		Value
241		 * Bridge Group Address		01-80-C2-00-00-00
242		 * (MAC Control) 802.3		01-80-C2-00-00-01
243		 * (Link Aggregation) 802.3	01-80-C2-00-00-02
244		 * 802.1X PAE address		01-80-C2-00-00-03
245		 *
246		 * 802.1AB LLDP 		01-80-C2-00-00-0E
247		 *
248		 * Others reserved for future standardization
249		 */
250		fwd_mask |= p->group_fwd_mask;
251		switch (dest[5]) {
252		case 0x00:	/* Bridge Group Address */
253			/* If STP is turned off,
254			   then must forward to keep loop detection */
255			if (p->br->stp_enabled == BR_NO_STP ||
256			    fwd_mask & (1u << dest[5]))
257				goto forward;
258			*pskb = skb;
259			__br_handle_local_finish(skb);
260			return RX_HANDLER_PASS;
261
262		case 0x01:	/* IEEE MAC (Pause) */
263			goto drop;
264
265		case 0x0E:	/* 802.1AB LLDP */
266			fwd_mask |= p->br->group_fwd_mask;
267			if (fwd_mask & (1u << dest[5]))
268				goto forward;
269			*pskb = skb;
270			__br_handle_local_finish(skb);
271			return RX_HANDLER_PASS;
272
273		default:
274			/* Allow selective forwarding for most other protocols */
275			fwd_mask |= p->br->group_fwd_mask;
276			if (fwd_mask & (1u << dest[5]))
277				goto forward;
278		}
279
280		/* Deliver packet to local host only */
281		NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, dev_net(skb->dev),
282			NULL, skb, skb->dev, NULL, br_handle_local_finish);
283		return RX_HANDLER_CONSUMED;
 
 
 
 
 
 
 
 
284	}
285
 
 
 
286forward:
287	switch (p->state) {
288	case BR_STATE_FORWARDING:
289		rhook = rcu_dereference(br_should_route_hook);
290		if (rhook) {
291			if ((*rhook)(skb)) {
292				*pskb = skb;
293				return RX_HANDLER_PASS;
294			}
295			dest = eth_hdr(skb)->h_dest;
296		}
297		/* fall through */
298	case BR_STATE_LEARNING:
299		if (ether_addr_equal(p->br->dev->dev_addr, dest))
300			skb->pkt_type = PACKET_HOST;
301
302		NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING,
303			dev_net(skb->dev), NULL, skb, skb->dev, NULL,
304			br_handle_frame_finish);
305		break;
306	default:
307drop:
308		kfree_skb(skb);
309	}
310	return RX_HANDLER_CONSUMED;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
311}