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/export.h>
20 #include <linux/rculist.h>
21 #include "br_private.h"
23 /* Hook for brouter */
24 br_should_route_hook_t __rcu *br_should_route_hook __read_mostly;
25 EXPORT_SYMBOL(br_should_route_hook);
27 static int br_pass_frame_up(struct sk_buff *skb)
29 struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev;
30 struct net_bridge *br = netdev_priv(brdev);
31 struct br_cpu_netstats *brstats = this_cpu_ptr(br->stats);
33 u64_stats_update_begin(&brstats->syncp);
34 brstats->rx_packets++;
35 brstats->rx_bytes += skb->len;
36 u64_stats_update_end(&brstats->syncp);
38 /* Bridge is just like any other port. Make sure the
39 * packet is allowed except in promisc modue when someone
40 * may be running packet capture.
42 if (!(brdev->flags & IFF_PROMISC) &&
43 !br_allowed_egress(br, br_get_vlan_info(br), skb)) {
48 skb = br_handle_vlan(br, br_get_vlan_info(br), skb);
55 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL,
59 /* note: already called with rcu_read_lock */
60 int br_handle_frame_finish(struct sk_buff *skb)
62 const unsigned char *dest = eth_hdr(skb)->h_dest;
63 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
64 struct net_bridge *br;
65 struct net_bridge_fdb_entry *dst;
66 struct net_bridge_mdb_entry *mdst;
70 if (!p || p->state == BR_STATE_DISABLED)
73 if (!br_allowed_ingress(p->br, nbp_get_vlan_info(p), skb, &vid))
76 /* insert into forwarding database after filtering to avoid spoofing */
78 br_fdb_update(br, p, eth_hdr(skb)->h_source);
80 if (!is_broadcast_ether_addr(dest) && is_multicast_ether_addr(dest) &&
81 br_multicast_rcv(br, p, skb))
84 if (p->state == BR_STATE_LEARNING)
87 BR_INPUT_SKB_CB(skb)->brdev = br->dev;
89 /* The packet skb2 goes to the local host (NULL to skip). */
92 if (br->dev->flags & IFF_PROMISC)
97 if (is_broadcast_ether_addr(dest))
99 else if (is_multicast_ether_addr(dest)) {
100 mdst = br_mdb_get(br, skb);
101 if (mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) {
102 if ((mdst && mdst->mglist) ||
103 br_multicast_is_router(br))
105 br_multicast_forward(mdst, skb, skb2);
112 br->dev->stats.multicast++;
113 } else if ((dst = __br_fdb_get(br, dest)) && dst->is_local) {
115 /* Do not forward the packet since it's local. */
122 br_forward(dst->dst, skb, skb2);
124 br_flood_forward(br, skb, skb2);
128 return br_pass_frame_up(skb2);
137 /* note: already called with rcu_read_lock */
138 static int br_handle_local_finish(struct sk_buff *skb)
140 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
142 br_fdb_update(p->br, p, eth_hdr(skb)->h_source);
143 return 0; /* process further */
147 * Return NULL if skb is handled
148 * note: already called with rcu_read_lock
150 rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
152 struct net_bridge_port *p;
153 struct sk_buff *skb = *pskb;
154 const unsigned char *dest = eth_hdr(skb)->h_dest;
155 br_should_route_hook_t *rhook;
157 if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
158 return RX_HANDLER_PASS;
160 if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
163 skb = skb_share_check(skb, GFP_ATOMIC);
165 return RX_HANDLER_CONSUMED;
167 p = br_port_get_rcu(skb->dev);
169 if (unlikely(is_link_local_ether_addr(dest))) {
171 * See IEEE 802.1D Table 7-10 Reserved addresses
174 * Bridge Group Address 01-80-C2-00-00-00
175 * (MAC Control) 802.3 01-80-C2-00-00-01
176 * (Link Aggregation) 802.3 01-80-C2-00-00-02
177 * 802.1X PAE address 01-80-C2-00-00-03
179 * 802.1AB LLDP 01-80-C2-00-00-0E
181 * Others reserved for future standardization
184 case 0x00: /* Bridge Group Address */
185 /* If STP is turned off,
186 then must forward to keep loop detection */
187 if (p->br->stp_enabled == BR_NO_STP)
191 case 0x01: /* IEEE MAC (Pause) */
195 /* Allow selective forwarding for most other protocols */
196 if (p->br->group_fwd_mask & (1u << dest[5]))
200 /* Deliver packet to local host only */
201 if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
202 NULL, br_handle_local_finish)) {
203 return RX_HANDLER_CONSUMED; /* consumed by filter */
206 return RX_HANDLER_PASS; /* continue processing */
212 case BR_STATE_FORWARDING:
213 rhook = rcu_dereference(br_should_route_hook);
217 return RX_HANDLER_PASS;
219 dest = eth_hdr(skb)->h_dest;
222 case BR_STATE_LEARNING:
223 if (ether_addr_equal(p->br->dev->dev_addr, dest))
224 skb->pkt_type = PACKET_HOST;
226 NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
227 br_handle_frame_finish);
233 return RX_HANDLER_CONSUMED;