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 const unsigned char *dest = eth_hdr(skb)->h_dest;
135 enum br_pkt_type pkt_type = BR_PKT_UNICAST;
136 struct net_bridge_fdb_entry *dst = NULL;
137 struct net_bridge_mdb_entry *mdst;
138 bool local_rcv, mcast_hit = false;
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 if (is_multicast_ether_addr(dest)) {
157 /* by definition the broadcast is also a multicast address */
158 if (is_broadcast_ether_addr(dest)) {
159 pkt_type = BR_PKT_BROADCAST;
162 pkt_type = BR_PKT_MULTICAST;
163 if (br_multicast_rcv(br, p, skb, vid))
168 if (p->state == BR_STATE_LEARNING)
171 BR_INPUT_SKB_CB(skb)->brdev = br->dev;
173 if (IS_ENABLED(CONFIG_INET) && skb->protocol == htons(ETH_P_ARP))
174 br_do_proxy_arp(skb, br, vid, p);
177 case BR_PKT_MULTICAST:
178 mdst = br_mdb_get(br, skb, vid);
179 if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
180 br_multicast_querier_exists(br, eth_hdr(skb))) {
181 if ((mdst && mdst->mglist) ||
182 br_multicast_is_router(br)) {
184 br->dev->stats.multicast++;
189 br->dev->stats.multicast++;
193 dst = br_fdb_find_rcu(br, dest, vid);
199 unsigned long now = jiffies;
202 return br_pass_frame_up(skb);
204 if (now != dst->used)
206 br_forward(dst->dst, skb, local_rcv, false);
209 br_flood(br, skb, pkt_type, local_rcv, false);
211 br_multicast_flood(mdst, skb, local_rcv, false);
215 return br_pass_frame_up(skb);
223 EXPORT_SYMBOL_GPL(br_handle_frame_finish);
225 static void __br_handle_local_finish(struct sk_buff *skb)
227 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
230 /* check if vlan is allowed, to avoid spoofing */
231 if (p->flags & BR_LEARNING && br_should_learn(p, skb, &vid))
232 br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false);
235 /* note: already called with rcu_read_lock */
236 static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
238 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
240 __br_handle_local_finish(skb);
242 BR_INPUT_SKB_CB(skb)->brdev = p->br->dev;
243 br_pass_frame_up(skb);
248 * Return NULL if skb is handled
249 * note: already called with rcu_read_lock
251 rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
253 struct net_bridge_port *p;
254 struct sk_buff *skb = *pskb;
255 const unsigned char *dest = eth_hdr(skb)->h_dest;
256 br_should_route_hook_t *rhook;
258 if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
259 return RX_HANDLER_PASS;
261 if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
264 skb = skb_share_check(skb, GFP_ATOMIC);
266 return RX_HANDLER_CONSUMED;
268 p = br_port_get_rcu(skb->dev);
269 if (p->flags & BR_VLAN_TUNNEL) {
270 if (br_handle_ingress_vlan_tunnel(skb, p,
271 nbp_vlan_group_rcu(p)))
275 if (unlikely(is_link_local_ether_addr(dest))) {
276 u16 fwd_mask = p->br->group_fwd_mask_required;
279 * See IEEE 802.1D Table 7-10 Reserved addresses
282 * Bridge Group Address 01-80-C2-00-00-00
283 * (MAC Control) 802.3 01-80-C2-00-00-01
284 * (Link Aggregation) 802.3 01-80-C2-00-00-02
285 * 802.1X PAE address 01-80-C2-00-00-03
287 * 802.1AB LLDP 01-80-C2-00-00-0E
289 * Others reserved for future standardization
292 case 0x00: /* Bridge Group Address */
293 /* If STP is turned off,
294 then must forward to keep loop detection */
295 if (p->br->stp_enabled == BR_NO_STP ||
296 fwd_mask & (1u << dest[5]))
299 __br_handle_local_finish(skb);
300 return RX_HANDLER_PASS;
302 case 0x01: /* IEEE MAC (Pause) */
305 case 0x0E: /* 802.1AB LLDP */
306 fwd_mask |= p->br->group_fwd_mask;
307 if (fwd_mask & (1u << dest[5]))
310 __br_handle_local_finish(skb);
311 return RX_HANDLER_PASS;
314 /* Allow selective forwarding for most other protocols */
315 fwd_mask |= p->br->group_fwd_mask;
316 if (fwd_mask & (1u << dest[5]))
320 /* Deliver packet to local host only */
321 NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, dev_net(skb->dev),
322 NULL, skb, skb->dev, NULL, br_handle_local_finish);
323 return RX_HANDLER_CONSUMED;
328 case BR_STATE_FORWARDING:
329 rhook = rcu_dereference(br_should_route_hook);
333 return RX_HANDLER_PASS;
335 dest = eth_hdr(skb)->h_dest;
338 case BR_STATE_LEARNING:
339 if (ether_addr_equal(p->br->dev->dev_addr, dest))
340 skb->pkt_type = PACKET_HOST;
342 NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING,
343 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
344 br_handle_frame_finish);
350 return RX_HANDLER_CONSUMED;