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 return netif_receive_skb(skb);
35 static int br_pass_frame_up(struct sk_buff *skb)
37 struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev;
38 struct net_bridge *br = netdev_priv(brdev);
39 struct net_bridge_vlan_group *vg;
40 struct pcpu_sw_netstats *brstats = this_cpu_ptr(br->stats);
42 u64_stats_update_begin(&brstats->syncp);
43 brstats->rx_packets++;
44 brstats->rx_bytes += skb->len;
45 u64_stats_update_end(&brstats->syncp);
47 vg = br_vlan_group(br);
48 /* Bridge is just like any other port. Make sure the
49 * packet is allowed except in promisc modue when someone
50 * may be running packet capture.
52 if (!(brdev->flags & IFF_PROMISC) &&
53 !br_allowed_egress(vg, skb)) {
60 skb = br_handle_vlan(br, vg, skb);
64 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
65 dev_net(indev), NULL, skb, indev, NULL,
66 br_netif_receive_skb);
69 static void br_do_proxy_arp(struct sk_buff *skb, struct net_bridge *br,
70 u16 vid, struct net_bridge_port *p)
72 struct net_device *dev = br->dev;
78 BR_INPUT_SKB_CB(skb)->proxyarp_replied = false;
80 if (dev->flags & IFF_NOARP)
83 if (!pskb_may_pull(skb, arp_hdr_len(dev))) {
84 dev->stats.tx_dropped++;
89 if (parp->ar_pro != htons(ETH_P_IP) ||
90 parp->ar_op != htons(ARPOP_REQUEST) ||
91 parp->ar_hln != dev->addr_len ||
95 arpptr = (u8 *)parp + sizeof(struct arphdr);
97 arpptr += dev->addr_len; /* sha */
98 memcpy(&sip, arpptr, sizeof(sip));
99 arpptr += sizeof(sip);
100 arpptr += dev->addr_len; /* tha */
101 memcpy(&tip, arpptr, sizeof(tip));
103 if (ipv4_is_loopback(tip) ||
104 ipv4_is_multicast(tip))
107 n = neigh_lookup(&arp_tbl, &tip, dev);
109 struct net_bridge_fdb_entry *f;
111 if (!(n->nud_state & NUD_VALID)) {
116 f = __br_fdb_get(br, n->ha, vid);
117 if (f && ((p->flags & BR_PROXYARP) ||
118 (f->dst && (f->dst->flags & BR_PROXYARP_WIFI)))) {
119 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, skb->dev, tip,
121 BR_INPUT_SKB_CB(skb)->proxyarp_replied = true;
128 /* note: already called with rcu_read_lock */
129 int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
131 const unsigned char *dest = eth_hdr(skb)->h_dest;
132 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
133 struct net_bridge *br;
134 struct net_bridge_fdb_entry *dst;
135 struct net_bridge_mdb_entry *mdst;
136 struct sk_buff *skb2;
140 if (!p || p->state == BR_STATE_DISABLED)
143 if (!br_allowed_ingress(p->br, nbp_vlan_group(p), skb, &vid))
146 /* insert into forwarding database after filtering to avoid spoofing */
148 if (p->flags & BR_LEARNING)
149 br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, false);
151 if (!is_broadcast_ether_addr(dest) && is_multicast_ether_addr(dest) &&
152 br_multicast_rcv(br, p, skb, vid))
155 if (p->state == BR_STATE_LEARNING)
158 BR_INPUT_SKB_CB(skb)->brdev = br->dev;
160 /* The packet skb2 goes to the local host (NULL to skip). */
163 if (br->dev->flags & IFF_PROMISC)
168 if (IS_ENABLED(CONFIG_INET) && skb->protocol == htons(ETH_P_ARP))
169 br_do_proxy_arp(skb, br, vid, p);
171 if (is_broadcast_ether_addr(dest)) {
174 } else if (is_multicast_ether_addr(dest)) {
175 mdst = br_mdb_get(br, skb, vid);
176 if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
177 br_multicast_querier_exists(br, eth_hdr(skb))) {
178 if ((mdst && mdst->mglist) ||
179 br_multicast_is_router(br))
181 br_multicast_forward(mdst, skb, skb2);
189 br->dev->stats.multicast++;
190 } else if ((dst = __br_fdb_get(br, dest, vid)) &&
193 /* Do not forward the packet since it's local. */
200 br_forward(dst->dst, skb, skb2);
202 br_flood_forward(br, skb, skb2, unicast);
206 return br_pass_frame_up(skb2);
214 EXPORT_SYMBOL_GPL(br_handle_frame_finish);
216 /* note: already called with rcu_read_lock */
217 static int br_handle_local_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
219 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
222 /* check if vlan is allowed, to avoid spoofing */
223 if (p->flags & BR_LEARNING && br_should_learn(p, skb, &vid))
224 br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false);
225 return 0; /* process further */
229 * Return NULL if skb is handled
230 * note: already called with rcu_read_lock
232 rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
234 struct net_bridge_port *p;
235 struct sk_buff *skb = *pskb;
236 const unsigned char *dest = eth_hdr(skb)->h_dest;
237 br_should_route_hook_t *rhook;
239 if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
240 return RX_HANDLER_PASS;
242 if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
245 skb = skb_share_check(skb, GFP_ATOMIC);
247 return RX_HANDLER_CONSUMED;
249 p = br_port_get_rcu(skb->dev);
251 if (unlikely(is_link_local_ether_addr(dest))) {
252 u16 fwd_mask = p->br->group_fwd_mask_required;
255 * See IEEE 802.1D Table 7-10 Reserved addresses
258 * Bridge Group Address 01-80-C2-00-00-00
259 * (MAC Control) 802.3 01-80-C2-00-00-01
260 * (Link Aggregation) 802.3 01-80-C2-00-00-02
261 * 802.1X PAE address 01-80-C2-00-00-03
263 * 802.1AB LLDP 01-80-C2-00-00-0E
265 * Others reserved for future standardization
268 case 0x00: /* Bridge Group Address */
269 /* If STP is turned off,
270 then must forward to keep loop detection */
271 if (p->br->stp_enabled == BR_NO_STP ||
272 fwd_mask & (1u << dest[5]))
276 case 0x01: /* IEEE MAC (Pause) */
280 /* Allow selective forwarding for most other protocols */
281 fwd_mask |= p->br->group_fwd_mask;
282 if (fwd_mask & (1u << dest[5]))
286 /* Deliver packet to local host only */
287 if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
288 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
289 br_handle_local_finish)) {
290 return RX_HANDLER_CONSUMED; /* consumed by filter */
293 return RX_HANDLER_PASS; /* continue processing */
299 case BR_STATE_FORWARDING:
300 rhook = rcu_dereference(br_should_route_hook);
304 return RX_HANDLER_PASS;
306 dest = eth_hdr(skb)->h_dest;
309 case BR_STATE_LEARNING:
310 if (ether_addr_equal(p->br->dev->dev_addr, dest))
311 skb->pkt_type = PACKET_HOST;
313 NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING,
314 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
315 br_handle_frame_finish);
321 return RX_HANDLER_CONSUMED;