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"
24 #include "br_private_tunnel.h"
26 /* Hook for brouter */
27 br_should_route_hook_t __rcu *br_should_route_hook __read_mostly;
28 EXPORT_SYMBOL(br_should_route_hook);
31 br_netif_receive_skb(struct net *net, struct sock *sk, struct sk_buff *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, NULL, 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_find_rcu(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_find_rcu(br, dest, vid);
198 unsigned long now = jiffies;
201 return br_pass_frame_up(skb);
203 if (now != dst->used)
205 br_forward(dst->dst, skb, local_rcv, false);
208 br_flood(br, skb, pkt_type, local_rcv, false);
210 br_multicast_flood(mdst, skb, local_rcv, false);
214 return br_pass_frame_up(skb);
222 EXPORT_SYMBOL_GPL(br_handle_frame_finish);
224 static void __br_handle_local_finish(struct sk_buff *skb)
226 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
229 /* check if vlan is allowed, to avoid spoofing */
230 if (p->flags & BR_LEARNING && br_should_learn(p, skb, &vid))
231 br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false);
234 /* note: already called with rcu_read_lock */
235 static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
237 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
239 __br_handle_local_finish(skb);
241 BR_INPUT_SKB_CB(skb)->brdev = p->br->dev;
242 br_pass_frame_up(skb);
247 * Return NULL if skb is handled
248 * note: already called with rcu_read_lock
250 rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
252 struct net_bridge_port *p;
253 struct sk_buff *skb = *pskb;
254 const unsigned char *dest = eth_hdr(skb)->h_dest;
255 br_should_route_hook_t *rhook;
257 if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
258 return RX_HANDLER_PASS;
260 if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
263 skb = skb_share_check(skb, GFP_ATOMIC);
265 return RX_HANDLER_CONSUMED;
267 p = br_port_get_rcu(skb->dev);
268 if (p->flags & BR_VLAN_TUNNEL) {
269 if (br_handle_ingress_vlan_tunnel(skb, p,
270 nbp_vlan_group_rcu(p)))
274 if (unlikely(is_link_local_ether_addr(dest))) {
275 u16 fwd_mask = p->br->group_fwd_mask_required;
278 * See IEEE 802.1D Table 7-10 Reserved addresses
281 * Bridge Group Address 01-80-C2-00-00-00
282 * (MAC Control) 802.3 01-80-C2-00-00-01
283 * (Link Aggregation) 802.3 01-80-C2-00-00-02
284 * 802.1X PAE address 01-80-C2-00-00-03
286 * 802.1AB LLDP 01-80-C2-00-00-0E
288 * Others reserved for future standardization
291 case 0x00: /* Bridge Group Address */
292 /* If STP is turned off,
293 then must forward to keep loop detection */
294 if (p->br->stp_enabled == BR_NO_STP ||
295 fwd_mask & (1u << dest[5]))
298 __br_handle_local_finish(skb);
299 return RX_HANDLER_PASS;
301 case 0x01: /* IEEE MAC (Pause) */
304 case 0x0E: /* 802.1AB LLDP */
305 fwd_mask |= p->br->group_fwd_mask;
306 if (fwd_mask & (1u << dest[5]))
309 __br_handle_local_finish(skb);
310 return RX_HANDLER_PASS;
313 /* Allow selective forwarding for most other protocols */
314 fwd_mask |= p->br->group_fwd_mask;
315 if (fwd_mask & (1u << dest[5]))
319 /* Deliver packet to local host only */
320 NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, dev_net(skb->dev),
321 NULL, skb, skb->dev, NULL, br_handle_local_finish);
322 return RX_HANDLER_CONSUMED;
327 case BR_STATE_FORWARDING:
328 rhook = rcu_dereference(br_should_route_hook);
332 return RX_HANDLER_PASS;
334 dest = eth_hdr(skb)->h_dest;
337 case BR_STATE_LEARNING:
338 if (ether_addr_equal(p->br->dev->dev_addr, dest))
339 skb->pkt_type = PACKET_HOST;
341 NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING,
342 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
343 br_handle_frame_finish);
349 return RX_HANDLER_CONSUMED;