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 "br_private.h"
21 /* Bridge group multicast address 802.1d (pg 51). */
22 const u8 br_group_address[ETH_ALEN] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
24 /* Hook for brouter */
25 br_should_route_hook_t __rcu *br_should_route_hook __read_mostly;
26 EXPORT_SYMBOL(br_should_route_hook);
28 static int br_pass_frame_up(struct sk_buff *skb)
30 struct net_device *indev, *brdev = BR_INPUT_SKB_CB(skb)->brdev;
31 struct net_bridge *br = netdev_priv(brdev);
32 struct br_cpu_netstats *brstats = this_cpu_ptr(br->stats);
34 u64_stats_update_begin(&brstats->syncp);
35 brstats->rx_packets++;
36 brstats->rx_bytes += skb->len;
37 u64_stats_update_end(&brstats->syncp);
42 return NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, indev, NULL,
46 /* note: already called with rcu_read_lock */
47 int br_handle_frame_finish(struct sk_buff *skb)
49 const unsigned char *dest = eth_hdr(skb)->h_dest;
50 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
51 struct net_bridge *br;
52 struct net_bridge_fdb_entry *dst;
53 struct net_bridge_mdb_entry *mdst;
56 if (!p || p->state == BR_STATE_DISABLED)
59 /* insert into forwarding database after filtering to avoid spoofing */
61 br_fdb_update(br, p, eth_hdr(skb)->h_source);
63 if (!is_broadcast_ether_addr(dest) && is_multicast_ether_addr(dest) &&
64 br_multicast_rcv(br, p, skb))
67 if (p->state == BR_STATE_LEARNING)
70 BR_INPUT_SKB_CB(skb)->brdev = br->dev;
72 /* The packet skb2 goes to the local host (NULL to skip). */
75 if (br->dev->flags & IFF_PROMISC)
80 if (is_broadcast_ether_addr(dest))
82 else if (is_multicast_ether_addr(dest)) {
83 mdst = br_mdb_get(br, skb);
84 if (mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) {
85 if ((mdst && mdst->mglist) ||
86 br_multicast_is_router(br))
88 br_multicast_forward(mdst, skb, skb2);
95 br->dev->stats.multicast++;
96 } else if ((dst = __br_fdb_get(br, dest)) && dst->is_local) {
98 /* Do not forward the packet since it's local. */
105 br_forward(dst->dst, skb, skb2);
107 br_flood_forward(br, skb, skb2);
111 return br_pass_frame_up(skb2);
120 /* note: already called with rcu_read_lock */
121 static int br_handle_local_finish(struct sk_buff *skb)
123 struct net_bridge_port *p = br_port_get_rcu(skb->dev);
125 br_fdb_update(p->br, p, eth_hdr(skb)->h_source);
126 return 0; /* process further */
129 /* Does address match the link local multicast address.
132 static inline int is_link_local(const unsigned char *dest)
134 __be16 *a = (__be16 *)dest;
135 static const __be16 *b = (const __be16 *)br_group_address;
136 static const __be16 m = cpu_to_be16(0xfff0);
138 return ((a[0] ^ b[0]) | (a[1] ^ b[1]) | ((a[2] ^ b[2]) & m)) == 0;
142 * Return NULL if skb is handled
143 * note: already called with rcu_read_lock
145 rx_handler_result_t br_handle_frame(struct sk_buff **pskb)
147 struct net_bridge_port *p;
148 struct sk_buff *skb = *pskb;
149 const unsigned char *dest = eth_hdr(skb)->h_dest;
150 br_should_route_hook_t *rhook;
152 if (unlikely(skb->pkt_type == PACKET_LOOPBACK))
153 return RX_HANDLER_PASS;
155 if (!is_valid_ether_addr(eth_hdr(skb)->h_source))
158 skb = skb_share_check(skb, GFP_ATOMIC);
160 return RX_HANDLER_CONSUMED;
162 p = br_port_get_rcu(skb->dev);
164 if (unlikely(is_link_local(dest))) {
165 /* Pause frames shouldn't be passed up by driver anyway */
166 if (skb->protocol == htons(ETH_P_PAUSE))
169 /* If STP is turned off, then forward */
170 if (p->br->stp_enabled == BR_NO_STP && dest[5] == 0)
173 if (NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_IN, skb, skb->dev,
174 NULL, br_handle_local_finish)) {
175 return RX_HANDLER_CONSUMED; /* consumed by filter */
178 return RX_HANDLER_PASS; /* continue processing */
184 case BR_STATE_FORWARDING:
185 rhook = rcu_dereference(br_should_route_hook);
189 return RX_HANDLER_PASS;
191 dest = eth_hdr(skb)->h_dest;
194 case BR_STATE_LEARNING:
195 if (!compare_ether_addr(p->br->dev->dev_addr, dest))
196 skb->pkt_type = PACKET_HOST;
198 NF_HOOK(NFPROTO_BRIDGE, NF_BR_PRE_ROUTING, skb, skb->dev, NULL,
199 br_handle_frame_finish);
205 return RX_HANDLER_CONSUMED;