2 * Handle incoming frames
3 * Linux ethernet bridge
6 * Lennert Buytenhek <buytenh@gnu.org>
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.
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>
21 #include <linux/export.h>
22 #include <linux/rculist.h>
23 #include "br_private.h"
25 /* Hook for brouter */
26 br_should_route_hook_t __rcu
*br_should_route_hook __read_mostly
;
27 EXPORT_SYMBOL(br_should_route_hook
);
30 br_netif_receive_skb(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
)
32 br_drop_fake_rtable(skb
);
33 return netif_receive_skb(skb
);
36 static int br_pass_frame_up(struct sk_buff
*skb
)
38 struct net_device
*indev
, *brdev
= BR_INPUT_SKB_CB(skb
)->brdev
;
39 struct net_bridge
*br
= netdev_priv(brdev
);
40 struct net_bridge_vlan_group
*vg
;
41 struct pcpu_sw_netstats
*brstats
= this_cpu_ptr(br
->stats
);
43 u64_stats_update_begin(&brstats
->syncp
);
44 brstats
->rx_packets
++;
45 brstats
->rx_bytes
+= skb
->len
;
46 u64_stats_update_end(&brstats
->syncp
);
48 vg
= br_vlan_group_rcu(br
);
49 /* Bridge is just like any other port. Make sure the
50 * packet is allowed except in promisc modue when someone
51 * may be running packet capture.
53 if (!(brdev
->flags
& IFF_PROMISC
) &&
54 !br_allowed_egress(vg
, skb
)) {
61 skb
= br_handle_vlan(br
, vg
, skb
);
64 /* update the multicast stats if the packet is IGMP/MLD */
65 br_multicast_count(br
, NULL
, skb
, br_multicast_igmp_type(skb
),
68 return NF_HOOK(NFPROTO_BRIDGE
, NF_BR_LOCAL_IN
,
69 dev_net(indev
), NULL
, skb
, indev
, NULL
,
70 br_netif_receive_skb
);
73 static void br_do_proxy_arp(struct sk_buff
*skb
, struct net_bridge
*br
,
74 u16 vid
, struct net_bridge_port
*p
)
76 struct net_device
*dev
= br
->dev
;
82 BR_INPUT_SKB_CB(skb
)->proxyarp_replied
= false;
84 if ((dev
->flags
& IFF_NOARP
) ||
85 !pskb_may_pull(skb
, arp_hdr_len(dev
)))
90 if (parp
->ar_pro
!= htons(ETH_P_IP
) ||
91 parp
->ar_op
!= htons(ARPOP_REQUEST
) ||
92 parp
->ar_hln
!= dev
->addr_len
||
96 arpptr
= (u8
*)parp
+ sizeof(struct arphdr
);
98 arpptr
+= dev
->addr_len
; /* sha */
99 memcpy(&sip
, arpptr
, sizeof(sip
));
100 arpptr
+= sizeof(sip
);
101 arpptr
+= dev
->addr_len
; /* tha */
102 memcpy(&tip
, arpptr
, sizeof(tip
));
104 if (ipv4_is_loopback(tip
) ||
105 ipv4_is_multicast(tip
))
108 n
= neigh_lookup(&arp_tbl
, &tip
, dev
);
110 struct net_bridge_fdb_entry
*f
;
112 if (!(n
->nud_state
& NUD_VALID
)) {
117 f
= __br_fdb_get(br
, n
->ha
, vid
);
118 if (f
&& ((p
->flags
& BR_PROXYARP
) ||
119 (f
->dst
&& (f
->dst
->flags
& BR_PROXYARP_WIFI
)))) {
120 arp_send(ARPOP_REPLY
, ETH_P_ARP
, sip
, skb
->dev
, tip
,
122 BR_INPUT_SKB_CB(skb
)->proxyarp_replied
= true;
129 /* note: already called with rcu_read_lock */
130 int br_handle_frame_finish(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
)
132 struct net_bridge_port
*p
= br_port_get_rcu(skb
->dev
);
133 const unsigned char *dest
= eth_hdr(skb
)->h_dest
;
134 enum br_pkt_type pkt_type
= BR_PKT_UNICAST
;
135 struct net_bridge_fdb_entry
*dst
= NULL
;
136 struct net_bridge_mdb_entry
*mdst
;
137 bool local_rcv
, mcast_hit
= false;
138 struct net_bridge
*br
;
141 if (!p
|| p
->state
== BR_STATE_DISABLED
)
144 if (!br_allowed_ingress(p
->br
, nbp_vlan_group_rcu(p
), skb
, &vid
))
147 nbp_switchdev_frame_mark(p
, skb
);
149 /* insert into forwarding database after filtering to avoid spoofing */
151 if (p
->flags
& BR_LEARNING
)
152 br_fdb_update(br
, p
, eth_hdr(skb
)->h_source
, vid
, false);
154 local_rcv
= !!(br
->dev
->flags
& IFF_PROMISC
);
155 if (is_multicast_ether_addr(dest
)) {
156 /* by definition the broadcast is also a multicast address */
157 if (is_broadcast_ether_addr(dest
)) {
158 pkt_type
= BR_PKT_BROADCAST
;
161 pkt_type
= BR_PKT_MULTICAST
;
162 if (br_multicast_rcv(br
, p
, skb
, vid
))
167 if (p
->state
== BR_STATE_LEARNING
)
170 BR_INPUT_SKB_CB(skb
)->brdev
= br
->dev
;
172 if (IS_ENABLED(CONFIG_INET
) && skb
->protocol
== htons(ETH_P_ARP
))
173 br_do_proxy_arp(skb
, br
, vid
, p
);
176 case BR_PKT_MULTICAST
:
177 mdst
= br_mdb_get(br
, skb
, vid
);
178 if ((mdst
|| BR_INPUT_SKB_CB_MROUTERS_ONLY(skb
)) &&
179 br_multicast_querier_exists(br
, eth_hdr(skb
))) {
180 if ((mdst
&& mdst
->mglist
) ||
181 br_multicast_is_router(br
)) {
183 br
->dev
->stats
.multicast
++;
188 br
->dev
->stats
.multicast
++;
192 dst
= __br_fdb_get(br
, dest
, vid
);
199 return br_pass_frame_up(skb
);
202 br_forward(dst
->dst
, skb
, local_rcv
, false);
205 br_flood(br
, skb
, pkt_type
, local_rcv
, false);
207 br_multicast_flood(mdst
, skb
, local_rcv
, false);
211 return br_pass_frame_up(skb
);
219 EXPORT_SYMBOL_GPL(br_handle_frame_finish
);
221 static void __br_handle_local_finish(struct sk_buff
*skb
)
223 struct net_bridge_port
*p
= br_port_get_rcu(skb
->dev
);
226 /* check if vlan is allowed, to avoid spoofing */
227 if (p
->flags
& BR_LEARNING
&& br_should_learn(p
, skb
, &vid
))
228 br_fdb_update(p
->br
, p
, eth_hdr(skb
)->h_source
, vid
, false);
231 /* note: already called with rcu_read_lock */
232 static int br_handle_local_finish(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
)
234 struct net_bridge_port
*p
= br_port_get_rcu(skb
->dev
);
236 __br_handle_local_finish(skb
);
238 BR_INPUT_SKB_CB(skb
)->brdev
= p
->br
->dev
;
239 br_pass_frame_up(skb
);
244 * Return NULL if skb is handled
245 * note: already called with rcu_read_lock
247 rx_handler_result_t
br_handle_frame(struct sk_buff
**pskb
)
249 struct net_bridge_port
*p
;
250 struct sk_buff
*skb
= *pskb
;
251 const unsigned char *dest
= eth_hdr(skb
)->h_dest
;
252 br_should_route_hook_t
*rhook
;
254 if (unlikely(skb
->pkt_type
== PACKET_LOOPBACK
))
255 return RX_HANDLER_PASS
;
257 if (!is_valid_ether_addr(eth_hdr(skb
)->h_source
))
260 skb
= skb_share_check(skb
, GFP_ATOMIC
);
262 return RX_HANDLER_CONSUMED
;
264 p
= br_port_get_rcu(skb
->dev
);
266 if (unlikely(is_link_local_ether_addr(dest
))) {
267 u16 fwd_mask
= p
->br
->group_fwd_mask_required
;
270 * See IEEE 802.1D Table 7-10 Reserved addresses
273 * Bridge Group Address 01-80-C2-00-00-00
274 * (MAC Control) 802.3 01-80-C2-00-00-01
275 * (Link Aggregation) 802.3 01-80-C2-00-00-02
276 * 802.1X PAE address 01-80-C2-00-00-03
278 * 802.1AB LLDP 01-80-C2-00-00-0E
280 * Others reserved for future standardization
283 case 0x00: /* Bridge Group Address */
284 /* If STP is turned off,
285 then must forward to keep loop detection */
286 if (p
->br
->stp_enabled
== BR_NO_STP
||
287 fwd_mask
& (1u << dest
[5]))
290 __br_handle_local_finish(skb
);
291 return RX_HANDLER_PASS
;
293 case 0x01: /* IEEE MAC (Pause) */
296 case 0x0E: /* 802.1AB LLDP */
297 fwd_mask
|= p
->br
->group_fwd_mask
;
298 if (fwd_mask
& (1u << dest
[5]))
301 __br_handle_local_finish(skb
);
302 return RX_HANDLER_PASS
;
305 /* Allow selective forwarding for most other protocols */
306 fwd_mask
|= p
->br
->group_fwd_mask
;
307 if (fwd_mask
& (1u << dest
[5]))
311 /* Deliver packet to local host only */
312 NF_HOOK(NFPROTO_BRIDGE
, NF_BR_LOCAL_IN
, dev_net(skb
->dev
),
313 NULL
, skb
, skb
->dev
, NULL
, br_handle_local_finish
);
314 return RX_HANDLER_CONSUMED
;
319 case BR_STATE_FORWARDING
:
320 rhook
= rcu_dereference(br_should_route_hook
);
324 return RX_HANDLER_PASS
;
326 dest
= eth_hdr(skb
)->h_dest
;
329 case BR_STATE_LEARNING
:
330 if (ether_addr_equal(p
->br
->dev
->dev_addr
, dest
))
331 skb
->pkt_type
= PACKET_HOST
;
333 NF_HOOK(NFPROTO_BRIDGE
, NF_BR_PRE_ROUTING
,
334 dev_net(skb
->dev
), NULL
, skb
, skb
->dev
, NULL
,
335 br_handle_frame_finish
);
341 return RX_HANDLER_CONSUMED
;