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 br_drop_fake_rtable(skb);
34 return netif_receive_skb(skb);
37 static int br_pass_frame_up(struct sk_buff *skb)
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);
44 u64_stats_update_begin(&brstats->syncp);
45 brstats->rx_packets++;
46 brstats->rx_bytes += skb->len;
47 u64_stats_update_end(&brstats->syncp);
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.
54 if (!(brdev->flags & IFF_PROMISC) &&
55 !br_allowed_egress(vg, skb)) {
62 skb = br_handle_vlan(br, NULL, vg, skb);
65 /* update the multicast stats if the packet is IGMP/MLD */
66 br_multicast_count(br, NULL, skb, br_multicast_igmp_type(skb),
69 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
70 dev_net(indev), NULL, skb, indev, NULL,
71 br_netif_receive_skb);
74 static void br_do_proxy_arp(struct sk_buff *skb, struct net_bridge *br,
75 u16 vid, struct net_bridge_port *p)
77 struct net_device *dev = br->dev;
83 BR_INPUT_SKB_CB(skb)->proxyarp_replied = false;
85 if ((dev->flags & IFF_NOARP) ||
86 !pskb_may_pull(skb, arp_hdr_len(dev)))
91 if (parp->ar_pro != htons(ETH_P_IP) ||
92 parp->ar_op != htons(ARPOP_REQUEST) ||
93 parp->ar_hln != dev->addr_len ||
97 arpptr = (u8 *)parp + sizeof(struct arphdr);
99 arpptr += dev->addr_len; /* sha */
100 memcpy(&sip, arpptr, sizeof(sip));
101 arpptr += sizeof(sip);
102 arpptr += dev->addr_len; /* tha */
103 memcpy(&tip, arpptr, sizeof(tip));
105 if (ipv4_is_loopback(tip) ||
106 ipv4_is_multicast(tip))
109 n = neigh_lookup(&arp_tbl, &tip, dev);
111 struct net_bridge_fdb_entry *f;
113 if (!(n->nud_state & NUD_VALID)) {
118 f = br_fdb_find_rcu(br, n->ha, vid);
119 if (f && ((p->flags & BR_PROXYARP) ||
120 (f->dst && (f->dst->flags & BR_PROXYARP_WIFI)))) {
121 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, skb->dev, tip,
123 BR_INPUT_SKB_CB(skb)->proxyarp_replied = true;
130 /* note: already called with rcu_read_lock */
131 int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
133 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
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 const unsigned char *dest;
139 struct net_bridge *br;
142 if (!p || p->state == BR_STATE_DISABLED)
145 if (!br_allowed_ingress(p->br, nbp_vlan_group_rcu(p), skb, &vid))
148 nbp_switchdev_frame_mark(p, skb);
150 /* insert into forwarding database after filtering to avoid spoofing */
152 if (p->flags & BR_LEARNING)
153 br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, false);
155 local_rcv = !!(br->dev->flags & IFF_PROMISC);
156 dest = eth_hdr(skb)->h_dest;
157 if (is_multicast_ether_addr(dest)) {
158 /* by definition the broadcast is also a multicast address */
159 if (is_broadcast_ether_addr(dest)) {
160 pkt_type = BR_PKT_BROADCAST;
163 pkt_type = BR_PKT_MULTICAST;
164 if (br_multicast_rcv(br, p, skb, vid))
169 if (p->state == BR_STATE_LEARNING)
172 BR_INPUT_SKB_CB(skb)->brdev = br->dev;
174 if (IS_ENABLED(CONFIG_INET) && skb->protocol == htons(ETH_P_ARP))
175 br_do_proxy_arp(skb, br, vid, p);
178 case BR_PKT_MULTICAST:
179 mdst = br_mdb_get(br, skb, vid);
180 if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
181 br_multicast_querier_exists(br, eth_hdr(skb))) {
182 if ((mdst && mdst->mglist) ||
183 br_multicast_is_router(br)) {
185 br->dev->stats.multicast++;
190 br->dev->stats.multicast++;
194 dst = br_fdb_find_rcu(br, dest, vid);
200 unsigned long now = jiffies;
203 return br_pass_frame_up(skb);
205 if (now != dst->used)
207 br_forward(dst->dst, skb, local_rcv, false);
210 br_flood(br, skb, pkt_type, local_rcv, false);
212 br_multicast_flood(mdst, skb, local_rcv, false);
216 return br_pass_frame_up(skb);
224 EXPORT_SYMBOL_GPL(br_handle_frame_finish);
226 static void __br_handle_local_finish(struct sk_buff *skb)
228 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
231 /* check if vlan is allowed, to avoid spoofing */
232 if (p->flags & BR_LEARNING && br_should_learn(p, skb, &vid))
233 br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false);
236 /* note: already called with rcu_read_lock */
237 static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
239 __br_handle_local_finish(skb);
241 /* return 1 to signal the okfn() was called so it's ok to use the skb */
246 * Return NULL if skb is handled
247 * note: already called with rcu_read_lock
249 rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
251 struct net_bridge_port *p;
252 struct sk_buff *skb = *pskb;
253 const unsigned char *dest = eth_hdr(skb)->h_dest;
254 br_should_route_hook_t *rhook;
256 if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
257 return RX_HANDLER_PASS;
259 if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
262 skb = skb_share_check(skb, GFP_ATOMIC);
264 return RX_HANDLER_CONSUMED;
266 p = br_port_get_rcu(skb->dev);
267 if (p->flags & BR_VLAN_TUNNEL) {
268 if (br_handle_ingress_vlan_tunnel(skb, p,
269 nbp_vlan_group_rcu(p)))
273 if (unlikely(is_link_local_ether_addr(dest))) {
274 u16 fwd_mask = p->br->group_fwd_mask_required;
277 * See IEEE 802.1D Table 7-10 Reserved addresses
280 * Bridge Group Address 01-80-C2-00-00-00
281 * (MAC Control) 802.3 01-80-C2-00-00-01
282 * (Link Aggregation) 802.3 01-80-C2-00-00-02
283 * 802.1X PAE address 01-80-C2-00-00-03
285 * 802.1AB LLDP 01-80-C2-00-00-0E
287 * Others reserved for future standardization
290 case 0x00: /* Bridge Group Address */
291 /* If STP is turned off,
292 then must forward to keep loop detection */
293 if (p->br->stp_enabled == BR_NO_STP ||
294 fwd_mask & (1u << dest[5]))
297 __br_handle_local_finish(skb);
298 return RX_HANDLER_PASS;
300 case 0x01: /* IEEE MAC (Pause) */
303 case 0x0E: /* 802.1AB LLDP */
304 fwd_mask |= p->br->group_fwd_mask;
305 if (fwd_mask & (1u << dest[5]))
308 __br_handle_local_finish(skb);
309 return RX_HANDLER_PASS;
312 /* Allow selective forwarding for most other protocols */
313 fwd_mask |= p->br->group_fwd_mask;
314 if (fwd_mask & (1u << dest[5]))
318 /* The else clause should be hit when nf_hook():
319 * - returns < 0 (drop/error)
320 * - returns = 0 (stolen/nf_queue)
321 * Thus return 1 from the okfn() to signal the skb is ok to pass
323 if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
324 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
325 br_handle_local_finish) == 1) {
326 return RX_HANDLER_PASS;
328 return RX_HANDLER_CONSUMED;
334 case BR_STATE_FORWARDING:
335 rhook = rcu_dereference(br_should_route_hook);
339 return RX_HANDLER_PASS;
341 dest = eth_hdr(skb)->h_dest;
344 case BR_STATE_LEARNING:
345 if (ether_addr_equal(p->br->dev->dev_addr, dest))
346 skb->pkt_type = PACKET_HOST;
348 NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING,
349 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
350 br_handle_frame_finish);
356 return RX_HANDLER_CONSUMED;