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);
29 static int br_netif_receive_skb(struct sock *sk, struct sk_buff *skb)
31 return netif_receive_skb(skb);
34 static int br_pass_frame_up(struct sk_buff *skb)
36 struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev;
37 struct net_bridge *br = netdev_priv(brdev);
38 struct pcpu_sw_netstats *brstats = this_cpu_ptr(br->stats);
39 struct net_port_vlans *pv;
41 u64_stats_update_begin(&brstats->syncp);
42 brstats->rx_packets++;
43 brstats->rx_bytes += skb->len;
44 u64_stats_update_end(&brstats->syncp);
46 /* Bridge is just like any other port. Make sure the
47 * packet is allowed except in promisc modue when someone
48 * may be running packet capture.
50 pv = br_get_vlan_info(br);
51 if (!(brdev->flags & IFF_PROMISC) &&
52 !br_allowed_egress(br, pv, skb)) {
59 skb = br_handle_vlan(br, pv, skb);
63 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
64 dev_net(indev), NULL, skb, indev, NULL,
65 br_netif_receive_skb);
68 static void br_do_proxy_arp(struct sk_buff *skb, struct net_bridge *br,
69 u16 vid, struct net_bridge_port *p)
71 struct net_device *dev = br->dev;
77 BR_INPUT_SKB_CB(skb)->proxyarp_replied = false;
79 if (dev->flags & IFF_NOARP)
82 if (!pskb_may_pull(skb, arp_hdr_len(dev))) {
83 dev->stats.tx_dropped++;
88 if (parp->ar_pro != htons(ETH_P_IP) ||
89 parp->ar_op != htons(ARPOP_REQUEST) ||
90 parp->ar_hln != dev->addr_len ||
94 arpptr = (u8 *)parp + sizeof(struct arphdr);
96 arpptr += dev->addr_len; /* sha */
97 memcpy(&sip, arpptr, sizeof(sip));
98 arpptr += sizeof(sip);
99 arpptr += dev->addr_len; /* tha */
100 memcpy(&tip, arpptr, sizeof(tip));
102 if (ipv4_is_loopback(tip) ||
103 ipv4_is_multicast(tip))
106 n = neigh_lookup(&arp_tbl, &tip, dev);
108 struct net_bridge_fdb_entry *f;
110 if (!(n->nud_state & NUD_VALID)) {
115 f = __br_fdb_get(br, n->ha, vid);
116 if (f && ((p->flags & BR_PROXYARP) ||
117 (f->dst && (f->dst->flags & BR_PROXYARP_WIFI)))) {
118 arp_send(ARPOP_REPLY, ETH_P_ARP, sip, skb->dev, tip,
120 BR_INPUT_SKB_CB(skb)->proxyarp_replied = true;
127 /* note: already called with rcu_read_lock */
128 int br_handle_frame_finish(struct sock *sk, struct sk_buff *skb)
130 const unsigned char *dest = eth_hdr(skb)->h_dest;
131 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
132 struct net_bridge *br;
133 struct net_bridge_fdb_entry *dst;
134 struct net_bridge_mdb_entry *mdst;
135 struct sk_buff *skb2;
139 if (!p || p->state == BR_STATE_DISABLED)
142 if (!br_allowed_ingress(p->br, nbp_get_vlan_info(p), skb, &vid))
145 /* insert into forwarding database after filtering to avoid spoofing */
147 if (p->flags & BR_LEARNING)
148 br_fdb_update(br, p, eth_hdr(skb)->h_source, vid, false);
150 if (!is_broadcast_ether_addr(dest) && is_multicast_ether_addr(dest) &&
151 br_multicast_rcv(br, p, skb, vid))
154 if (p->state == BR_STATE_LEARNING)
157 BR_INPUT_SKB_CB(skb)->brdev = br->dev;
159 /* The packet skb2 goes to the local host (NULL to skip). */
162 if (br->dev->flags & IFF_PROMISC)
167 if (IS_ENABLED(CONFIG_INET) && skb->protocol == htons(ETH_P_ARP))
168 br_do_proxy_arp(skb, br, vid, p);
170 if (is_broadcast_ether_addr(dest)) {
173 } else if (is_multicast_ether_addr(dest)) {
174 mdst = br_mdb_get(br, skb, vid);
175 if ((mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) &&
176 br_multicast_querier_exists(br, eth_hdr(skb))) {
177 if ((mdst && mdst->mglist) ||
178 br_multicast_is_router(br))
180 br_multicast_forward(mdst, skb, skb2);
188 br->dev->stats.multicast++;
189 } else if ((dst = __br_fdb_get(br, dest, vid)) &&
192 /* Do not forward the packet since it's local. */
199 br_forward(dst->dst, skb, skb2);
201 br_flood_forward(br, skb, skb2, unicast);
205 return br_pass_frame_up(skb2);
213 EXPORT_SYMBOL_GPL(br_handle_frame_finish);
215 /* note: already called with rcu_read_lock */
216 static int br_handle_local_finish(struct sock *sk, struct sk_buff *skb)
218 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
221 /* check if vlan is allowed, to avoid spoofing */
222 if (p->flags & BR_LEARNING && br_should_learn(p, skb, &vid))
223 br_fdb_update(p->br, p, eth_hdr(skb)->h_source, vid, false);
224 return 0; /* process further */
228 * Return NULL if skb is handled
229 * note: already called with rcu_read_lock
231 rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
233 struct net_bridge_port *p;
234 struct sk_buff *skb = *pskb;
235 const unsigned char *dest = eth_hdr(skb)->h_dest;
236 br_should_route_hook_t *rhook;
238 if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
239 return RX_HANDLER_PASS;
241 if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
244 skb = skb_share_check(skb, GFP_ATOMIC);
246 return RX_HANDLER_CONSUMED;
248 p = br_port_get_rcu(skb->dev);
250 if (unlikely(is_link_local_ether_addr(dest))) {
251 u16 fwd_mask = p->br->group_fwd_mask_required;
254 * See IEEE 802.1D Table 7-10 Reserved addresses
257 * Bridge Group Address 01-80-C2-00-00-00
258 * (MAC Control) 802.3 01-80-C2-00-00-01
259 * (Link Aggregation) 802.3 01-80-C2-00-00-02
260 * 802.1X PAE address 01-80-C2-00-00-03
262 * 802.1AB LLDP 01-80-C2-00-00-0E
264 * Others reserved for future standardization
267 case 0x00: /* Bridge Group Address */
268 /* If STP is turned off,
269 then must forward to keep loop detection */
270 if (p->br->stp_enabled == BR_NO_STP ||
271 fwd_mask & (1u << dest[5]))
275 case 0x01: /* IEEE MAC (Pause) */
279 /* Allow selective forwarding for most other protocols */
280 fwd_mask |= p->br->group_fwd_mask;
281 if (fwd_mask & (1u << dest[5]))
285 /* Deliver packet to local host only */
286 if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN,
287 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
288 br_handle_local_finish)) {
289 return RX_HANDLER_CONSUMED; /* consumed by filter */
292 return RX_HANDLER_PASS; /* continue processing */
298 case BR_STATE_FORWARDING:
299 rhook = rcu_dereference(br_should_route_hook);
303 return RX_HANDLER_PASS;
305 dest = eth_hdr(skb)->h_dest;
308 case BR_STATE_LEARNING:
309 if (ether_addr_equal(p->br->dev->dev_addr, dest))
310 skb->pkt_type = PACKET_HOST;
312 NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING,
313 dev_net(skb->dev), NULL, skb, skb->dev, NULL,
314 br_handle_frame_finish);
320 return RX_HANDLER_CONSUMED;