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 /* note: already called with rcu_read_lock */
75 int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
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;
86 if (!p || p->state == BR_STATE_DISABLED)
89 if (!br_allowed_ingress(p->br, nbp_vlan_group_rcu(p), skb, &vid))
92 nbp_switchdev_frame_mark(p, skb);
94 /* insert into forwarding database after filtering to avoid spoofing */
96 if (p->flags & BR_LEARNING)
97 br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, false);
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;
107 pkt_type = BR_PKT_MULTICAST;
108 if (br_multicast_rcv(br, p, skb, vid))
113 if (p->state == BR_STATE_LEARNING)
116 BR_INPUT_SKB_CB(skb)->brdev = br->dev;
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;
130 msg = br_is_nd_neigh_msg(skb, &_msg);
132 br_do_suppress_nd(skb, br, vid, p, msg);
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)) {
143 br->dev->stats.multicast++;
148 br->dev->stats.multicast++;
152 dst = br_fdb_find_rcu(br, dest, vid);
158 unsigned long now = jiffies;
161 return br_pass_frame_up(skb);
163 if (now != dst->used)
165 br_forward(dst->dst, skb, local_rcv, false);
168 br_flood(br, skb, pkt_type, local_rcv, false);
170 br_multicast_flood(mdst, skb, local_rcv, false);
174 return br_pass_frame_up(skb);
182 EXPORT_SYMBOL_GPL(br_handle_frame_finish);
184 static void __br_handle_local_finish(struct sk_buff *skb)
186 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
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);
194 /* note: already called with rcu_read_lock */
195 static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
197 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
199 __br_handle_local_finish(skb);
201 BR_INPUT_SKB_CB(skb)->brdev = p->br->dev;
202 br_pass_frame_up(skb);
207 * Return NULL if skb is handled
208 * note: already called with rcu_read_lock
210 rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
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;
217 if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
218 return RX_HANDLER_PASS;
220 if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
223 skb = skb_share_check(skb, GFP_ATOMIC);
225 return RX_HANDLER_CONSUMED;
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)))
234 if (unlikely(is_link_local_ether_addr(dest))) {
235 u16 fwd_mask = p->br->group_fwd_mask_required;
238 * See IEEE 802.1D Table 7-10 Reserved addresses
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
246 * 802.1AB LLDP 01-80-C2-00-00-0E
248 * Others reserved for future standardization
250 fwd_mask |= p->group_fwd_mask;
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]))
259 __br_handle_local_finish(skb);
260 return RX_HANDLER_PASS;
262 case 0x01: /* IEEE MAC (Pause) */
265 case 0x0E: /* 802.1AB LLDP */
266 fwd_mask |= p->br->group_fwd_mask;
267 if (fwd_mask & (1u << dest[5]))
270 __br_handle_local_finish(skb);
271 return RX_HANDLER_PASS;
274 /* Allow selective forwarding for most other protocols */
275 fwd_mask |= p->br->group_fwd_mask;
276 if (fwd_mask & (1u << dest[5]))
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;
288 case BR_STATE_FORWARDING:
289 rhook = rcu_dereference(br_should_route_hook);
293 return RX_HANDLER_PASS;
295 dest = eth_hdr(skb)->h_dest;
298 case BR_STATE_LEARNING:
299 if (ether_addr_equal(p->br->dev->dev_addr, dest))
300 skb->pkt_type = PACKET_HOST;
302 NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING,
303 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
304 br_handle_frame_finish);
310 return RX_HANDLER_CONSUMED;